Final Report Upper Raghughat

7/17/2019 Final Report Upper Raghughat

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Tundi Power CompanyKathmandu, Nepal

Volume OneMain ReportMay, 2012

Feasiility !tudy

"pper Rahu#hat $ydroele%tri% Pro&e%t

'pe( )ner#y P*t+ imited

2-. Ka/an%ho inaya/ Mar#, Taha%hal, Chhauni,Kathmandu1, Nepal Tel3 -4415242 Fa(3 -4415261-5.



Upper Rahughat Hydroelectric ProjectTable of Contents

Tale o7 Contents

Table of Contents............................................................................................................................1

List of Tables...................................................................................................................................1

List of Figures.................................................................................................................................1

List of Drawings..............................................................................................................................1

List of Annexes...............................................................................................................................2

Salient Features of the Project........................................................................................................1

1.0 !T"#D$CT#!............................................................................................................1%1

1.1 &eneral.......................................................................................................................1%11.2 'ac(groun)................................................................................................................1%2

1.* Location an) Access..................................................................................................1%2

1.+ Sco,e an) #bjecti-e..................................................................................................1%*

1. Project De-elo,/ent Strateg...................................................................................1%*

1. Stu) xecution.........................................................................................................1%+

2.0 DSC"PT#! #F P"#3CT A"A.............................................................................2%1

2.1 &eneral.......................................................................................................................2%1

2.2 Location.....................................................................................................................2%12.* Phsical Features.......................................................................................................2%1

2.+ Accessibilit..............................................................................................................2%2

*.0 T#P#&"AP4CAL S$"56 A!D 7APP!&............................................................*%1

*.1 ntro)uction................................................................................................................*%1

*.2 Sco,e of 8or(...........................................................................................................*%1

*.* A-ailable nfor/ation an) Data.................................................................................*%1

*.+ &eneral.......................................................................................................................*%2

*. 7etho)olog..............................................................................................................*%2*..1 Des( Stu).............................................................................................................*%2

*..2 "econnaissance Sur-e.........................................................................................*%2

*..* 7onu/entation of &roun) Control Points............................................................*%2

*..+ Control Tra-ersing.................................................................................................*%2

*.. 4ori9ontal an) 5ertical Control.............................................................................*%+

*. Data Processing.........................................................................................................*%

*.: Detaile) To,ogra,hical Sur-e.................................................................................*%*.; 7a,,ing.....................................................................................................................*%

*.< "i-er Cross Sections..................................................................................................*%

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*.10 Annexes.....................................................................................................................*%

+.0 46D"#L#&CAL ST$DS.........................................................................................+%1

+.1 Phsiogra,hical Characteristics of the 'ale,hi 'asin...............................................+%1+.1.1 "i-er an) Catch/ent Characteristics.....................................................................+%1

+.1.2 The Cli/ate...........................................................................................................+%2

+.2 Strea/ Flows.............................................................................................................+%+

+.2.1 'asic 4istoric Data................................................................................................+%+

+.2.2 7etho)olog..........................................................................................................+%

+.2.2.1 "egional Analsis A,,roach..........................................................................+%

+.2.* Strea/ flow Analsis at nta(e site on 'agar =hola...........................................+%11

+.2.+ "i,arian "elease..................................................................................................+%12

+.* Flow Duration Cur-e...............................................................................................+%12

+.+ Floo) Flows.............................................................................................................+%1+

+.+.1 'ac(groun)..........................................................................................................+%1+

+.+.2 "egional Floo) Fre>uenc Analsis....................................................................+%1+

+.+.* Dr Season Di-ersion Floo)................................................................................+%1<

+.+.+ stablish/ent of &auging Station an) Discharge 7easure/ent.........................+%20

.0 SD7!T#! ST$DS..............................................................................................%1.1 &eneral.......................................................................................................................%1

.2 4i/alaan Se)i/ent 6iel) Techni>ues.....................................................................%1

.* Se)i/ent Data #btain fro/ "ahughat Project..........................................................%2

.0 &#L#&CAL A!D &#TC4!CAL ST$DS......................................................%1

.1 ntro)uction................................................................................................................%1

.2 #bjecti-es..................................................................................................................%1

.* Literature "e-iew......................................................................................................%2

.+ 7etho)olog..............................................................................................................%2.+.1 &eological stu)....................................................................................................%2

.+.2 &eotechnical stu).................................................................................................%2

.+.2.1 "oc( /ass an) soil classification...................................................................%2

.+.2.2 "oc( su,,ort )esign.......................................................................................%*

.+.2.* Slo,e stabilit analsis...................................................................................%*

. "egional &eolog......................................................................................................%*

. Seis/icit..................................................................................................................%+

.: &eolog of the Project Area......................................................................................%

.:.1 &eneral &eolog....................................................................................................%





.:.2 4ea)wor(s Area.....................................................................................................%:

.:.* 4ea)race Tunnel....................................................................................................%;

.:.*.1 "oc( 7ass Classification.............................................................................%11.:.*.2 "oc( 7ass Su,,ort......................................................................................%1*

.:.*.* "oc( 7ass Strength......................................................................................%1+

.:.+ Construction A)it.................................................................................................%2*

.:. Surge shaft...........................................................................................................%2*

.:. Penstoc( Align/ent.............................................................................................%2*

.:.: Powerhouse Area.................................................................................................%2+

.; Construction 7aterial..............................................................................................%2

.< Du/,ing ? 7uc( Dis,osal Sites..............................................................................%2

.10 Conclusions an) "eco//en)ations........................................................................%2

.10.1 Conclusions..........................................................................................................%2

.10.1.1 4ea)wor(s....................................................................................................%2

.10.1.2 Desan)ing 'asin...........................................................................................%2

.10.1.* 4ea)race Tunnel an) A)it............................................................................%2

.10.1.+ Surge Shaft...................................................................................................%2

.10.1. Penstoc( align/ent.......................................................................................%2:

.10.1. Powerhouse..................................................................................................%2:

.10.2 "eco//en)ations for Sub Surface &eological n-estigation.............................%2:

:.0 ALT"!AT5 ST$DS..............................................................................................:%1

:.1 ntro)uction................................................................................................................:%1

:.2 Casca)e De-elo,/ent...............................................................................................:%2

:.* Power &eneration fro/ 'agar =hola........................................................................:%2

:.+ The Choice of the Con-eance Sste/.....................................................................:%*

:. Location an) Choice of the Powerhouse...................................................................:%*

;.0 P"#3CT #PT7@AT#!............................................................................................;%1

;.1 ntro)uction an) #bjecti-e........................................................................................;%1

;.2 Project De-elo,/ent Strateg an) Alternati-e Stu)...............................................;%1

;.* Design Discharge ? nstalle) Ca,acit #,ti/i9ation.................................................;%2

;.*.1 Assu/,tions..........................................................................................................;%*

;.*.2 A,,roach an) 7etho)olog..................................................................................;%*

;.*.* "ange of #,tions...................................................................................................;%+;.+ "i-er Flows................................................................................................................;%

;.+.1 7ini/u/ #,erating Le-el an) Tail 8ater Le-el..................................................;%





;.+.2 4igh Floo) Le-el at 'agar =hola 4ea)wor(s......................................................;%

;. Conce,tual Laout an) Design..................................................................................;%:

;..1 Di-ersion 8eir at 'agar =hola..............................................................................;%:;..2 "i-er nta(e at 'agar =hola..................................................................................;%;

;..* Desan)ing 'asin at 'agar =hola...........................................................................;%;

;..+ Concrete 'ox Cul-ert............................................................................................;%<

;.. Collection Cha/ber...............................................................................................;%<

;.. 4ea)race Tunnel Penstoc( an) Dro, shaft...........................................................;%<

;..: Surge Tan(...........................................................................................................;%11

;..; Powerhouse an) Tailrace.....................................................................................;%11

;..< Access "oa).........................................................................................................;%11

;..10 Trans/ission Line................................................................................................;%12

;. sti/ate of nerg an) Ca,acit Potential.............................................................;%1*

;.: Cost sti/ate...........................................................................................................;%1*

;.; Financial Analsis....................................................................................................;%1

;.< Analsis an) "esults................................................................................................;%1;

;.10 Conclusion an) "eco//en)ation...........................................................................;%1<

<.0 P"#3CT DSC"PT#! A!D DS&!.....................................................................<%1<.1 &eneral.......................................................................................................................<%1

<.2 Project Configuration.................................................................................................<%1

<.2.1 &eneral Arrange/ent of the Project Co/,onents.................................................<%2

<.2.1.1 4ea)wor(s &eneral Arrange/ent..................................................................<%2

<.2.1.2 #-erflow 8eir................................................................................................<%*

<.2.1.* $n)ersluice.....................................................................................................<%+

<.2.1.+ nta(e..............................................................................................................<%

<.2.1. Desan)ing 'asin an) Flushing Structure.......................................................<%

<.2.1. Foreba...........................................................................................................<%

<.2.1.: Power &eneration at 'agar =hola..................................................................<%:

<.2.1.; Cut an) Co-er 'ox Cul-ert............................................................................<%<

<.2.1.< Collection Cha/ber........................................................................................<%<

<.2.1.10 4ea)race Tunnel.............................................................................................<%<

<.2.1.11 Surge Tan(....................................................................................................<%10

<.2.1.12 Surface Penstoc(..........................................................................................<%1*<.2.1.1* Powerhouse..................................................................................................<%1





<.2.1.1+ Tailrace Channel an) #utlet Structure.........................................................<%1

<.2.1.1 Switchar)....................................................................................................<%1:

<.2.1.1 Access "oa).................................................................................................<%1:<.2.2 4)raulic Steel Structures...................................................................................<%1;

<.2.2.1 &eneral.........................................................................................................<%1;

<.2.2.2 Design Criteria.............................................................................................<%1;

<.2.2.* $n)er Sluice &ate B'agar =hola................................................................<%1;

<.2.2.+ $n)er Sluice Sto,log B'agar =hola............................................................<%1<

<.2.2. &ra-el Tra, &ate B'agar =hola..................................................................<%20

<.2.2. &ra-eltra, Sto,log B'agar =hola...............................................................<%20<.2.2.: nta(e Trashrac( B'agar =hola...................................................................<%21

<.2.2.; nta(e Sluice &ate B'agar =hola................................................................<%22

<.2.2.< nta(e Sto,log B'agar =hola.......................................................................<%22

<.2.2.10 Desan)er Flushing &ate B'agar =hola.......................................................<%2*

<.2.2.11 Penstoc( nlet &ates.....................................................................................<%2+

<.2.2.12 Tailrace #utlet Sto,logs B'agar =hola.......................................................<%2+

<.2.2.1* Tailrace outlet Sto,log B"ahughat 7angale................................................<%2

<.2.2.1+ Collection Cha/ber Trashrac( B$,,er "ahughat.......................................<%2

<.2.2.1 Tunnel nlet &ate B$,,er "ahughat............................................................<%2

<.2.2.1 /ergenc Closing 5al-e B$,,er "ahughat..............................................<%2:

<.2.2.1: Tailrace outlet Sto,log B$,,er "ahughat....................................................<%2:

<.2.* 8ater 8as..........................................................................................................<%2;

<.2.*.1 Steel Penstoc( B'agar =hola.......................................................................<%2;

<.2.*.2 Steel Penstoc( an) Steel Liner B$,,er "ahughat.......................................<%2<

<.2.*.* 'ifurcation Pi,e............................................................................................<%*0

<.2.+ Powerhouse lectro 7echanical >ui,/ent.......................................................<%*0

<.2.+.1 Plant Ca,acit...............................................................................................<%*0

<.2.+.2 !u/ber of $nits an) $nit Ca,acit.............................................................<%*1

<.2.+.* Selection of the Turbine T,e.......................................................................<%*1

<.2.+.+ S,ecific S,ee) an) Snchronus S,ee).........................................................<%*1

<.2.+. Descri,tion of the Turbines..........................................................................<%*2

<.2.+. Princi,al Characteristics...............................................................................<%*2

<.2.+.: Descri,tion of 7ain Parts.............................................................................<%**





<.2.+.; Turbine &o-ernor.........................................................................................<%*

<.2.+.< Pressure #il Su,,l Sste/.........................................................................<%*

<.2.+.10 Turbine nlet 5al-e.......................................................................................<%*<.2.+.11 Station 8ater Sste/...................................................................................<%*

<.2.+.12 Drainages an) Dewatering Sste/...............................................................<%*:

<.2.+.1* &rease Su,,l Sste/..................................................................................<%*;

<.2.+.1+ 'ra(es an) 3ac(ing Sste/..........................................................................<%*;

<.2.+.1 Co/,resse) Air Sste/...............................................................................<%*;

<.2.+.1 #il 4an)ling Sste/....................................................................................<%*<

<.2.+.1: Air%Con)itioning an) 5entilation Sste/....................................................<%*<<.2.+.1; Fire Protection Sste/.................................................................................<%*<

<.2.+.1< 7echanical 8or(sho,..................................................................................<%*<

<.2.+.20 le-ator........................................................................................................<%+0

<.2.+.21 Powerhouse #-erhea) Tra-eling Crane.......................................................<%+0

<.2. Power &eneration at 'agar =hola.......................................................................<%+1

<.2..1 Plant Ca,acit...............................................................................................<%+1

<.2..2 !u/ber of $nits an) $nit Ca,acit.............................................................<%+1

<.2..* Selection of Turbine T,e............................................................................<%+1

<.2..+ S,ecific S,ee) an) Snchronus S,ee).........................................................<%+1

<.2.. Descri,tion of Turbines................................................................................<%+2

<.2.. Princi,al Characteristics...............................................................................<%+2

<.2..: Descri,tion of the 7ain Parts.......................................................................<%+2

<.2..; Turbine &o-ernor.........................................................................................<%+*

<.2..< Pressure #il Su,,l Sste/.........................................................................<%++

<.2..10 Turbine nlet 5al-e.......................................................................................<%++

<.2..11 Station 8ater Sste/...................................................................................<%++

<.2..12 Drainages an) Dewatering Sste/...............................................................<%+

<.2..1* &rease Su,,l Sste/..................................................................................<%+

<.2..1+ 'ra(es an) 3ac(ing Sste/..........................................................................<%+

<.2..1 Co/,resse) Air Sste/...............................................................................<%+

<.2..1 #il 4an)ling Sste/....................................................................................<%+

<.2..1: Air%Con)itioning an) 5entilation Sste/....................................................<%+

<.2..1; Fire Protection Sste/.................................................................................<%+

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<.2..1< Powerhouse 4oisting Sste/.......................................................................<%+:

<.2. Powerhouse lectrical >ui,/ent.......................................................................<%+:

<.2..1 &enerator xcitation an) Ancillaries...........................................................<%+:<.2..2 7ain Power Transfor/ers............................................................................<%+<

<.2.: Powerhouse lectrical Auxiliaries.......................................................................<%+<

<.2.:.1 AC Powerhouse Auxiliaries.........................................................................<%+<

<.2.:.2 DC Powerhouse Auxiliaries.........................................................................<%1

<.2.:.* /ergenc Diesel &enerator........................................................................<%1

<.2.:.+ Control an) Protection..................................................................................<%2

<.2.:. 45 Switchgear an) Trans/ission Line Protection......................................<%2<.2.:. &roun)ing Barthing...................................................................................<%*

<.2.:.: 45 Switchar)?Substation...........................................................................<%*

<.2.:.; Control an) n)ication at the 4ea)wor(s.....................................................<%*

<.2.:.< Co//unication Sste/...............................................................................<%+

<.2.; Trans/ission Line................................................................................................<%+

<.2.< Construction Power.............................................................................................<%+

<.2.10 Power &eneration at 'agar =hola.......................................................................<%

10.0 P#8" 5AC$AT#! ST$D6..................................................................................10%1

10.1 ntro)uction..............................................................................................................10%1

10.2 xisting Trans/ission Sste/.................................................................................10%1

10.* Trans/ission Line in the 5icinit............................................................................10%2

10.+ Trans/ission 5oltage selection................................................................................10%2

10. 5oltage Selection $sing /,irical For/ula...........................................................10%2

10. 5oltage Selection 'ase) $,on 5oltage of the Local Substation.............................10%*

10.: 5oltage Selection $sing Ca,itali9e) Cost...............................................................10%*10.:.1 7etho) 1..............................................................................................................10%+

10.:.1.1 Plant Costs....................................................................................................10%+

10.:.1.2 Plant Loss Duration......................................................................................10%+

10.:.1.* nerg Cost..................................................................................................10%

10.:.1.+ #,eration an) 7aintenance..........................................................................10%

10.:.1. Discount Factor............................................................................................10%

10.:.2 7etho) 2..............................................................................................................10%

10.:.* Alternati-e Sche/e..............................................................................................10%

10.:.*.1 Technical Analsis........................................................................................10%:

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10.:.*.2 cono/ic Analsis.......................................................................................10%:

10.:.*.* cono/ic n-est/ent Cost...........................................................................10%;

10.:.*.+ "esult of Analsis.........................................................................................10%;10.; Conclusions an) "eco//en)ations........................................................................10%;

11.0 C#7P$TAT#! #F P"#3CT #$TP$TS A!D "LATD '!FTS.................11%1

11.1 ntro)uction..............................................................................................................11%1

11.2 De,en)able Flow.....................................................................................................11%1

11.* &ross 4ea) an) !et 4ea)........................................................................................11%2

11.+ #-erall fficienc....................................................................................................11%2

11. nerg Co/,utation................................................................................................11%2

11. nerg &eneration fro/ 'agar =hola.....................................................................11%*12.0 C#!ST"$CT#! PLA!!!&....................................................................................12%1

12.1 &eneral.....................................................................................................................12%1

12.2 Site Con)ition..........................................................................................................12%1

12.2.1 To,ogra,h an) Lan) $se...................................................................................12%1

12.2.2 Cli/atic Con)itions.............................................................................................12%1

12.* Access to the Site.....................................................................................................12%1

12.+ Construction of $,,er "ahughat 4)roelectric Project..........................................12%2

12.+.1 Construction Ca/,..............................................................................................12%*

12.+.2 Project Construction 8or( an) Construction Planning.......................................12%*

12.+.* 'asic Assu/,tions...............................................................................................12%+

12.+.+ Di-ersion During Construction............................................................................12%+

12.+. 7ain "i-er nta(e $n)ersluice an) the /ergenc S,illwa............................12%

12.+. 8eir......................................................................................................................12%

12.+.: Desan)er an) Flushing structure.........................................................................12%

12.+.; Foreba................................................................................................................12%12.+.< Collection Cha/ber.............................................................................................12%

12.+.10 Cut an) Co-er 'ox Cul-ert.................................................................................12%:

12.+.11 A)it Tunnels.........................................................................................................12%:

12.+.12 4ea)race Tunnel #utlet Portal.............................................................................12%;

12.+.1* 4ea)race Tunnel..................................................................................................12%;

12.+.1+ Surge Tan(...........................................................................................................12%;

12.+.1 Surface Penstoc(..................................................................................................12%;

12.+.1 Dro,Shaft.............................................................................................................12%;

12.+.1: 4igh Pressure Tunnel...........................................................................................12%<

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12.+.1; Powerhouse..........................................................................................................12%<

12.+.1< Tailrace Pon) an) #utlet Structure......................................................................12%<

12.+.20 lectro%7echanical >ui,/ent...........................................................................12%<12.+.21 Switchar)...........................................................................................................12%<

12.+.22 Testing an) Co//issioning..............................................................................12%10

12.+.2* Conclusions........................................................................................................12%10

1*.0 'ASL! !5"#!7!TAL ST$D6 B..........................................................1*%1

1*.1 &eneral.....................................................................................................................1*%1

1*.2 &eneral ntro)uction of the Project.........................................................................1*%1

1*.* Data "e>uire/ent an) Stu) 7etho)olog............................................................1*%2

1*.+ "e-iew of Plans?Policies Acts "ules "egulations &ui)elines Strategies 7anualsan) Con-entions......................................................................................................1*%*

1*. Descri,tion of the xisting n-iron/ent................................................................1*%*

1*..1 Phsical n-iron/ent..........................................................................................1*%*

1*..1.1 To,ogra,h...................................................................................................1*%*

1*..1.2 Cli/ate an) 4)rolog................................................................................1*%*

1*..1.* 8atershe).....................................................................................................1*%*

1*..1.+ Slo,e Stabilit an) Lan) Sli)e.....................................................................1*%+

1*..1. &eolog........................................................................................................1*%+

1*..2 'iological n-iron/ent.......................................................................................1*%+

1*..2.1 Forest an) 5egetation...................................................................................1*%+

1*..2.2 8il)life.........................................................................................................1*%

1*..2.* A-ian Fauna..................................................................................................1*%

1*..2.+ A>uatic Fauna...............................................................................................1*%

1*..2. "are en)angere) an) ,rotecte) s,ecies of Flora an) Fauna........................1*%

1*..* Socio%econo/ic an) Cultural n-iron/ent.........................................................1*%

1*..*.1 5DC Profile..................................................................................................1*%

1*. n-iron/ental /,act.............................................................................................1*%:

1*..1 'eneficial /,act.................................................................................................1*%:

1*..2 A)-erse /,act....................................................................................................1*%;

1*..2.1 Phsical........................................................................................................1*%;

1*..2.2 'iological.....................................................................................................1*%<

1*..2.* Socio%econo/ic an) Cultural n-iron/ent...............................................1*%101*.: Alternati-e analsis...............................................................................................1*%1*

1*.:.1 Design Alternati-e.............................................................................................1*%1*

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1*.:.1.1 Casca)e )e-elo,/ent.................................................................................1*%1*

1*.:.1.2 Power generation fro/ 'agar =hola..........................................................1*%1+

1*.; 7itigation an) nhance/ent 7easures.................................................................1*%11*.;.1 nhance/ent 7easures.....................................................................................1*%1

1*.;.1.1 Phsical n-iron/ent.................................................................................1*%1

1*.< 'iological n-iron/ent.........................................................................................1*%1:

1*.10 Socio%econo/ic an) cultural en-iron/ent............................................................1*%1<

1*.11 7itigation nhance/ent an) Cor,orate Social "es,onsibilit Costs..................1*%22

1*.12 7onitoring Plan.....................................................................................................1*%22

1*.1* Conlcusion.............................................................................................................1*%22

1+.0 C#ST ST7AT..........................................................................................................1+%11+.1 &eneral.....................................................................................................................1+%1

1+.2 Criteria Assu/,tions an) cost co/,onents............................................................1+%1

1+.* sti/ating /etho)olog..........................................................................................1+%1

1+.*.1 Ci-il 8or(s..........................................................................................................1+%1

1+.*.2 "esource Costs.....................................................................................................1+%2

1+.*.2.1 Labour "ates.................................................................................................1+%2

1+.*.2.2 Construction >ui,/ent "ate......................................................................1+%2

1+.*.2.* Construction 7aterial...................................................................................1+%*

1+.*.* $nit Costs............................................................................................................1+%*

1+.*.+ n)irect Costs.......................................................................................................1+%*

1+.*. Preli/inar 8or(s...............................................................................................1+%*

1+.*. Access "oa).........................................................................................................1+%+

1+.+ Ci-il 8or( Cost.......................................................................................................1+%+

1+. 4)ro/echanical 8or(s Cost.................................................................................1+%+

1+. lectro/echanical >ui,/ent.................................................................................1+%+1+.: Trans/ission Line Substations an) Switchar).....................................................1+%

1+.; ngineering an) 7anage/ent Cost.........................................................................1+%

1+.< Contingencies..........................................................................................................1+%

1+.10 "esettel/ent an) n-iron/ental 7itigation 8or(.................................................1+%

1+.11 #wners cost.............................................................................................................1+%

1+.12 Project Cost..............................................................................................................1+%

1.0 DS'$"S7!T SC4D$L....................................................................................1%1

1.1 "esettle/ent Su,,ort Facilities Access "oa) an) Pre,arator 8or(s..................1%21.2 Ci-il 8or(s..............................................................................................................1%2

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1.* &ates 5al-es an) Steel Line...................................................................................1%*

1.+ Turbine an) &enerator.............................................................................................1%*

1. Trans/ission Line an) Substation...........................................................................1%*1. Detaile) ngineering an) Construction Su,er-ision...............................................1%*

1.0 P"#3CT 5AL$AT#!.............................................................................................1%1

1.1 &eneral.....................................................................................................................1%1

1.2 7etho)olog............................................................................................................1%1

1.2.1 sti/ation of Project Costs.................................................................................1%1

1.2.2 sti/ation of Project 'enefits.............................................................................1%2

1.2.* Decision 7a(ing Tools........................................................................................1%2

1.* Assu/,tions............................................................................................................1%*1.+ "esult of the Analsis..............................................................................................1%+

1. Discussion of the "esult........................................................................................1%10

1:.0 '!FTS F"#7 CLA! D5L#P7!T 7C4A!S7...................................1:%1

1:.1 'ac(groun)..............................................................................................................1:%1

1:.2 'enefit fro/ CD7 to $,,er "ahughat 4)ro lectric Project..............................1:%2

1;.0 C#!CL$S#!S A!D "C#77!DAT#!S..........................................................1;%1




Upper Rahughat Hydroelectric ProjectList of Tables

ist o7 Tales

Table *%1 List of 'asic Control Points...................................................................................*%*Table *%2 Co%or)inates an) ele-ation of tra-erse ,oints.......................................................*%*Table +%1 7onthl Data for Te/,erature an) "elati-e 4u/i)it........................................+%*Table +%2 Characteristics of Strea/gauge Stations BSource D47.....................................+%Table +%* Long Ter/ 7ean 7onthl Flows..........................................................................+%Table +%+ Long Ter/ 7ean 7onthl Flows........................................................................+%11Table +% 7ean 7onthl Flows of "ahughat =hola at 3hi..................................................+%11Table +% Ti/e xcee)ence of Discharges at 7angale Da/site.........................................+%12Table +%: Ti/e xcee)ence of Discharges at 'agar Da/site.............................................+%12Table +%; "egional Floo) Analsis E &an)a(i 'asin..........................................................+%1Table +%< sti/ate) Floo)s for $,,er "ahughat 4)roelectric Project B/*?s..................+%1<

Table +%10 Dr Season Floo)s at 5arious Projects................................................................+%1<Table %1 "oc( /ass classification along hea)race tunnel align/ent.................................%12Table %2 Distribution of roc(?su,,ort t,e along hea)race tunnel....................................%12Table %* Su//ar of su,,ort length for hea)race tunnel..................................................%12Table %+ "oc( /ass su,,ort for tunnel..............................................................................%1+Table % n,ut -alues ? ,ara/eters for calculation of roc( /ass strength ,ara/eters.......%1Table % #ut,ut roc( /ass strength ,ara/eters.................................................................%1Table %: n,ut -alues ? ,ara/eters for calculation of roc( /ass strength ,ara/eters.......%1Table %; #ut,ut roc( /ass strength ,ara/eters.................................................................%1:Table ;%1 "ange of #,tions...................................................................................................;%Table ;%2 fficiencies............................................................................................................;%

Table ;%* A-erage 7onthl Flows........................................................................................;%Table ;%+ Features of nta(e for ach #,tion........................................................................;%;Table ;% Features of the Desan)ing 'asins for ach Ca,acit #,tion................................;%<Table ;% Features of Collection Cha/ber............................................................................;%<Table ;%: cono/ic Para/eters use) in #,ti/i9ation........................................................;%10Table ;%; Features of 4ea)race Tunnel Surface Penstoc( an) Steel Line) Dro, Shaft.....;%10Table ;%< sti/ate) Dia/eter of Surge Tan(......................................................................;%11Table ;%10 Features of Powerhouse an) Tailrace Channel for ach Ca,acit #,tion..........;%11Table ;%11 Trans/ission Line Alternati-es...........................................................................;%12Table ;%12 Su//ar of Power an) Annual nerg for Different Design Discharge............;%1*Table ;%1* $nit "ates of 7ajor Ci-il 8or( te/s.................................................................;%1+Table ;%1+ Su//ar of Cost for Different #,tions..............................................................;%1Table ;%1 Su//ar of Total Financial Cost B7illion "s...................................................;%1:Table ;%1 Su//ar of the "esult........................................................................................;%1;Table <%1 Details of Anchor 'loc(s.....................................................................................<%1+Table <%2 Preli/inar Para/eters of the &enerators...........................................................<%+;Table <%* Preli/inar Para/eters for the Transfor/ers......................................................<%+<Table <%+ 7ain Para/eters for &enerators an) Transfor/ers.............................................<%Table 10%1 Plant Loss Duration.............................................................................................10%Table 11%1 Su//ar of the 4ea) Loss Bin /eters...............................................................11%2Table 11%2 7onthl nerg &eneration fro/ $,,er "ahughat 4P....................................11%*

Table 11%* 7onthl nerg &eneration fro/ 'agar =hola..................................................11%+Table 1+%1 $nit "ates............................................................................................................1+%*Table 1+%2 Su//ar of the Project Cost...............................................................................1+%Table 1%1 Disburse/ent of Costs Accor)ing to Acti-ities...................................................1%2

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Upper Rahughat Hydroelectric ProjectList of Tables

Table 1%2 Cost Allocation for Ci-il Co/,onents................................................................1%2Table 1%* Disburse/ent Sche)ule for the Project................................................................1%+Table 1%1 Su//ar of Total Financial Cost for $,,er "ahughat"ahughat 4P...............1%

Table 1%2 Disburse/ent of >uit an) Debt for $,,er "ahughat 4P..............................1%Table 1%* Financial Analsis wirh "es,ect to >uit n-este/ent.....................................1%Table 1%+ Su//ar of the "e>uire) A-erage Tariff for Different Cases.......................1%10Table 1:%1 nerg De/an) Projection $, to 20:1?:2..........................................................1:%2Table 1:%2 Power De/an) Projection $, to 20:1?:2.........................................................1:%2Table 1:%* Para/eters for the -aluation of the /ission Cre)it.........................................1:%+Table 1:%+ Para/eters for the -aluation of the /ission Cre)it.........................................1:%+Table 1:% 'enefit -aluation fro/ 'agar =hola Power Plant............................................1:%+

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Upper Rahughat Hydroelectric Project List of Figures

ist o7 Fi#ures

Figure +%1 7ean 7onthl "ainfall at Lete..............................................................................+%+Figure +%2 7ean 7onthl "ainfall at 'ega............................................................................+%+Figure +%* Flow Duration Cur-e at 'agar nta(e site...........................................................+%1*Figure +%+ Long%ter/ 7ean 7onthl Flow at 'agar nta(e site /*?s.................................+%1*Figure %1 &rain Si9e Distribution Cur-e...............................................................................%2Figure %1 Location of ,roject area in regional geological /a,.............................................%*Figure %2 Seis/icit /a, of !e,al........................................................................................%Figure %* Stereogra,hic Projection of Discontinuities Bnta(e Portal Area.........................%<Figure %+ Stereogra,hic Projection of )iscontinuities BA)it !o. 1 Area............................%10

Figure % Stereogra,hic Projection of Discontinuities BSurge Tan( Area..........................%11Figure % sti/ate) su,,ort categories base) on -alues.................................................%1*Figure %: Tunnel )efor/ation -ersus roc( /ass strength to in%situ stress..........................%1;Figure %; Finite ele/ent /esh generate) for stress analsis...............................................%1<Figure %< Plot of 7ajor Princi,al Stress BG 1.....................................................................%20Figure %10 Plot of Strength Factor Contour.......................................................................%20Figure %11 $se of roc( su,,ort consisting of roc( bolt an) liner Bshotcrete....................%21Figure %12 Strength factor contour )istribution aroun) exca-ation boun)ar...................%22Figure %1* Plot of ,ercentage of iel)e) ele/ents after using su,,ort.............................%22Figure ;%1 #,ti/i9ation of Design Discharge......................................................................;%1<Figure <%1 #,ti/i9ation of Surface Penstoc( for 'agar =hola Powerhouse..........................<%:

Figure <%2 #,ti/i9ation of the Conrete Line) 4ea)race Tunnel..........................................<%10Figure <%* Full Loa) "ejection.............................................................................................<%12Figure <%+ Full Loa) Acce,tance after i//e)iate the Full Loa) "ejection B1 $nit...........<%12Figure <% #,ti/i9ation of the Surface Penstoc(.................................................................<%1*Figure 10%1 Chart for StillHs For/ula for Trans/ission......................................................10%*Figure 10%2 Ca,itali9e) Cost -ersus nstalle) Ca,acit Cur-e...........................................10%Figure 12%1 Construction Sche)ule.........................................................................................12%11

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Upper Rahughat Hydroelectric ProjectList of Annexes

ist o7 8rawin#s

1 Location 7a, L7%012 &eneral Project Laout $"%PL%01* &eneral Project Laout of "ahughat 7angale An)

$,,er "ahughat 4P $"%PL%02+ &eological 7a, of Project Area $"%&%PA%01 &eological 7a, of 4ea)wor(s Area $"%&%48%01 &eological Profile I "oc( 7ass Classification

Along 4ea)race Tunnel $"%&%4"T%1?2: &eological Profile I "oc( 7ass Classification $"%&%4"T%2?2

Along 4ea)race Tunnel

; &eological 7a, of Powerhouse Area $"%&%P4%01< &eological Section along Penstoc( Align/ent $"%&%P4%0210 Location 7a, for 'orrow Area an) 7uc(

Dis,osal BDu/,ing Sites $"%&%7D%0111 Pro,ose) lectrical "esisti-it Lines B4ea)wor(s $"%"%0112 Pro,ose) lectrical "esisti-it Lines BPowerhouse $"%"%021* 4ea)wor(s Laout at 'agar =hola $"%48%011+ 4ea)wor(s Section $"%48%021 4ea)wor(s Section $"%48%0*1 L%Profile of Desan)er $"%48%0+

1: Profile of Flushing Channels $"%48%01; Details of 'ox Cul-ert $"%48%01< 'agar =hola Powerhouse $"%'P4%0120 Longitu)inal Profile of 4ea)race Tunnel $"%4"T%0121 Longitu)inal Profile of 4ea)race Tunnel $"%4"T%0222 4ea)race Tunnel Sections $"%4"T%0*2* &eneral Arrange/ent of Powerhouse An)

A,,urtenant Structures $"%P4P%012+ Surge Tan( Cross Sections $"%ST%012 Longitu)inal Profile of Surge Tan( Penstoc(

an) Dro, Shaft $"%PS%012 T,ical Penstoc( Cross Sections $"%PS%022: Cross Sections of Dro, Shaft an) A)it Tunnel $"%PS%0*2; Anchor 'loc(s Plan an) Sections $"%PS%0+2< &eneral Laout of Powerhosue $"%P4%01*0 Powerhouse Floor Plans $"%P4%02*1 Cross Section of Powerhouse $"%P4%0**2 Longitu)inal Section of Powerhouse $"%P4%0+** Single Line Diagra/ of Powerhouse $"%L%01*+ Single Line Diagra/ of Auxiliar Su,,l $"%L%02* Laout of Switchar) an) $,,er "ahughat P4 $"%L%0** nterconnection Sche/es of Trans/ission Line $"%L%0+*: "esult of Loa) Flow Stu) $"%L%0

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Upper Rahughat Hydroelectric ProjectList of Annexes

*; Align/ent of Trans/ission Line $"%L%0

ist o7 'nne(es

Annex A To,ogra,hic Sur-eAnnex ' 4)rological an) Se)i/ent Stu)iesAnnex C #,ti/i9ation of Design DischargeAnnex D Project DesignAnnex Power -acuationAnnex F Project nerg 'enefit Co/,utationAnnex & T#" for nitial n-iron/ental xa/inationAnnex 4 Cost sti/ation

Annex Financial -aluation

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Upper Rahughat Hydroelectric ProjectSalient Features

!alient Features o7 the Pro&e%t

o%ation Pa(ha,ani 5DC Chi/(ola 5DCan) Dagna/ Dar/ija 5DC of 7ag)i District8estern De-elo,/ent "egion of

!e,alLongitu)e ;*0*0J00K to ;*0*1J0K Latitu)e 2;02J+K ! to 2;02;J*0 !

Type "#" 4)ro BCasca)e De-elo,/ent8ith "ahughat 7angale at$,strea/

$ydrolo#y

Catch/ent Area of 'agar =hola +.0 (/ 2 Design Discharge 1.2 /*?s B12.0 /*?s fro/ "ahughat%

7angale 4P an) *.2 /*?s fro/'agar =hola

Design Floo) B1100rs at 'agar =hola 2*0.< /*?sAnnual Floo) B12rs at 'agar =hola +;.< /*?s

9eir at a#ar Khola

T,e Concrete &ra-it Da/Crest le-ation 1;.0 /asl

Crest Length 20.0 /4igh Floo) le-el 1:0.; /aslSluice Si9e BLength x 4eight *.0 / x 2.1 /Discharge Ca,acit of $n)ersluice at !8L +<.<+ /*?s

:nta/e at a#ar Khola

T,e Si)e nta(eSi9e B8i)th x 4eight .0 / M 2. /

Crest Le-el 1.0 /asl !or/al 8ater Le-el 1;.0 /aslSi9e of nta(e Sluice BLength x 4eight *. / x 0. /

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Crest Le-el #f Sluice 1.0 /asl

7axi/u/ Dischage through Sluice .; /*?s

8esander at a#ar Khola

T,e Dufour ?nter/ittent Flushing T,eDesign Discharge *.2 /*?s

!u/ber of 'as 1Length *.0 /Si9e B8i)th x 4eight .0 / x *.0 /Flushing Si/,le 4ea) cutting

!or/al 8ater Le-el 1:. /asl7axi/u/ 8ater Le-el 1;.0+ /asl

Foreay at a#ar Khola

Si9e BLength x 8i)th x De,th 11. / x .0 / x *.0 /

!ur7a%e pensto%/ 7or a#ar Khola P;$

Si9e BLength x 8i)th x 4eight 1;.0 / x <.0 / x ;.: / !o of $nit 2Turbine T,e Francis Turbine B4ori9ontal AxisTailrace BLength x 8i)th x 4eight 2+.0 / x 2.0 / x 1.0 /

Power and )ner#y <a#ar Khola=

&ross hea) 1*.0 / !et hea) 12.< /nstalle) Ca,acit *2+ =wAnnual A-erage nerg 2.0+ &8hA-erage Dr Season nerg 0.** &8hA-erage 8et Season nerg 1.:1 &8h

9ater Con*eyan%e !ystem <Cut and Co*ered o( Cul*ert=

Si9e BLength x 8i)th x 4eight 0.0 / x *.2; / x *.2 /

9ater Con*eyan%e !ystem <$eadra%e Tunnel=

T,e Concrete Line) Stan)ar) 4orseshoe





8ith Circular Finishe)

Length +:*< /#,t. Finishe) Dia/eter *.+ /

!ur#e Tan/

Dia/eter <.0 /4eight *;.:; /

!or/al 8ater Le-el 11.:2 /asl7axi/u/ 8ater Le-el 1:.1 /asl7ini/u/ 8ater Le-el 1*.2; /asl

!ur7a%e Pensto%/

Length *:.* /Dia/eter 2.+ /Steel Lining Thic(ness ;%2+ //

8rop !ha7t and $i#h Pressure Tunnel

Dia/eter 2.+ /Dro, Shaft ncline) Length 22*.0 /Steel Lining Thic(ness 2+%*2 //Length of Steel Line) 4ori9ontal Tunnel 10<. /Steel Lining Thic(ness *2 //

Powerhouse

T,e SurfaceSi9e BLength x 8i)th x 4eight +*.0 / x 1.0 / x 22.0 /

!o of $nit 2Turbine T,e Pelton Turbine B5ertical Axis

!wit%hyard

Si9e BLength x 8i)th 0.0 / x +0.0 /

'%%ess and Pro&e%t Roads

Access "oa) 20 =/





Project "oa) ; (/

Transmission ine Fa%ilities

Sub Station "ahughat B!ALength an) Ca,acit ; (/ B1*2 (5

Power and )ner#y < From Rahu#hat Powerhouse =

&ross hea) *:;.0 / !et hea) *:2.* /nstalle) Ca,acit +;. 78Annual A-erage nerg 2;+.+1 &8h

A-erage Dr Season nerg +1.; &8hA-erage 8et Season nerg 2+2.1 &8h

Total Annual A-erage nerg 2;.+ &8hA-erage Annual Saleable nerg 2+.<: &8h

Saleable Dr Season nerg *;.<: &8hSaleable 8et Season nerg 22.0 &8h

Pro&e%t Cost

Project Cost *.;** 7illion $SNCost ,er (8 1*0* $SN

Finan%ial indi%ators

Total Financial Cost ;0.;+ 7!"sDebt >uit "atio :0 *0Total >uit 2+1:.0 7!"sTotal Debt *<.:< 7!"s

nterest on Debt 12.0 O"eturn on >uit 1;.0 OA-erage nerg Cost .*; !"s?(8h B2012 Price Le-el7axi/u/ nerg Cost .;* !"s?(8h BFro/ 2020 #nwar)Debt Ser-ice "atio Bn 1st 6ear 1.1'?C "atio 1.2+F"" 1*.+; OPabac( Perio) ;.*2 6rs








Upper Rahughat Hydroelectric Project ntroduction

1+0 :NTRO8"CT:ON

1+1 >eneral

!e,alHs h)ro,ower ,otential is -ast an) can be )e-elo,e) for the generation of re-enues tofun) )e-elo,/ent ,rogra/s an) contribute to the o-erall )e-elo,/ent of the countr. Des,iteha-ing an esti/ate) ,otential of ;*000 78 an) an econo/icall feasible ,otential of about+2000 78 !e,alHs current total installe) generation ca,acit in the ntegrate) !ational Power Sste/ is /erel ;< 78 out of which h)ro,ower has a share of onl * 78. There areso/e ** h)ro,ower ,lants in o,eration 20 in the ,ublic sector 1* in the ,ri-ate sector an)so/e *0 s/all h)ro,ower ,lants in isolate) o,eration. #nl about 1: O of the total ,o,ulationhas access to electricit. The >ualit of su,,l is relati-el ,oor the )r season generationca,acit is ina)e>uate sste/ losses are fairl high at 2 O an) outages are >uite fre>uent.

"ecogni9ing the nee) to a))ress these issues an) to )e-elo, its water resources ,otential&o-ern/ent of !e,al has )efine) a ,ower )e-elo,/ent ,lan BShort Ter/ 7e)iu/ Ter/ an)Long Ter/ as ,er !e,al 8ater Plan 200*. The strateg in the ,ower sector is two fol) to see( )onor financing for large h)ro,ower ,rojects while encouraging ,ri-ate financing for /e)iu/

an) s/all ,rojects. The &o-ern/ent of !e,al is encouraging ,ri-ate in-est/ent in this sector.Potential h)ro,ower ,rojects are generall ran(e) on the basis of technical econo/ical socialan) en-iron/ental criteria. n or)er to attract ,ri-ate sector in-est/ent in this sector the&o-ern/ent of !e,al has for/ulate) se,arate ,olicies an) legal fra/ewor( in this sector whichare as follows

• 4)ro,ower De-elo,/ent Polic 1<<2 an) 2001• lectricit Act 1<<2 B "egulations 1<<* which is now un)er a/en)/ent• !e,al lectricit "egulator Co//ission Act BDraft with in)e,en)ent regulator

/echanis/

As state) abo-e although nature has en)owe) !e,al with a -er -ast networ( of ri-ers resultingin a -er high ,otential for h)ro,ower generation?)e-elo,/ent onl a -er negligible ,ortionof this -ast ,otential has been ex,loite). The )e-elo,/ent of h)ro,ower in !e,al too( rootal/ost a centur ago with the construction of the 00 (8 Phar,ing 4)roelectric Project.4owe-er serious atte/,ts at ta,,ing the countrHs -ast h)ro,ower ,otential began onl in thesecon) half of the ,re-ious centur with the co//issioning of Trishuli 4)roelectric Project in

!uwa(ot District. Since then a nu/ber of h)ro,ower ,rojects /ostl of run%of%ri-er t,eha-e been built in !e,al through the concerte) efforts of &o-ern/ent of !e,al !e,allectricit Authorit B!A an) the ,ri-ate sector. These ,rojects generate a total of ;< 78

constituting of about ;; O of the countrHs total installe) ca,acit of * 78. B!A Fiscal 6ear 200<?2010 E A 6ear in "e-iew

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Chapter One

:NTRO8"CT:ON




8ith no substantial a))ition to the sste/ since the co//issioning of the 1++ 78 =ali&an)a(i A 4)roelectric Project in 2001 an) the recentl co/,lete) :0 78 7i))le7arshang)i 4)roelectric Project in 200< an) so/e s/all ,rojects in the ,ri-ate sector the

countr is struggling to /eet the < O annual increase in electricit )e/an) with its ,resentgeneration resources. Currentl the countr is reeling un)er a ,er,etual state of loa) she))ingwhich is ha/,ering not onl the )ail acti-ities of the general ,eo,le but also has seriousi/,acts on the in)ustrial an) econo/ic growth of the countr.

n or)er to )eal with the i/,en)ing crisis !e,al i//e)iatel nee)s both short an) long ter//easures for aug/enting its electricit su,,l sste/. The feasibilit stu) of $,,er "ahughat4)roelectric Project an) its subse>uent co//issioning is an effort being /a)e b Tun)i Power Co/,an in whate-er s/all wa it can to counter this situation an) u,lift the o-erall

)e-elo,/ent of the countr.

1+2 a%/#round

This Feasibilit Stu) "e,ort for $,,er "ahughat 4)roelectric Project has been ,re,are) for Tun)i Power Co/,an entruste) for the )e-elo,/ent of this ,roject b the De,art/ent of lectricit De-elo,/ent BD#D 7inistr of 8ater "esource B7o8" &o-ern/ent of !e,alB&o! to /eet the increasing ,ower )e/an) of !e,al.

Tun)i Power Co/,an recei-e) the license to carr out the sur-e an) the feasibilit stu) of

this ,roject an) has engage) APM nerg BP Lt). to loo( into the technical an) financial-iabilit of the ,roject an) to ,re,are the o-erall feasibilit stu) re,ort for the ,roject.

This feasibilit stu) re,ort has been co/,ile) to ,resent the fin)ings of the stu) for the ,roject. All wor(s carrie) out towar)s the fulfill/ent of the stu) has been ,resente) in thefollowing cha,ters.

1+ o%ation and '%%ess

$,,er "ahughat 4)roelectric Project is locate) in Pa(ha,ani 5DC Chi/(ola 5DC an)Dagna/ Dar/ija 5DC of 7ag)i District in 8estern !e,al. The site is locate) about **+ (/northwest of =ath/an)u an) about ;* =/ west of Po(hara.

"ahughat "i-er is a /ajor tributar of =ali &an)a(i "i-er an) /eets the =ali &an)a(i "i-er near the ,lace calle) &aleshwor of &hatan 5DC. The ,roject site lies between latitu)es of 2;02J+K an) 2;02;J*0 !orth an) between longitu)es ;*0*0J00K an) ;*0*1J0K ast. The

,ro,ose) hea)wor(s site is locate) about 10 / u,strea/trea/ fro/ the confluence of 'agar =hola an) "ahughat "i-er near Chi/(hola 5illage. The ,owerhouse is ,ro,ose) to be locate)on the left ban( of "ahughat "i-er a,,roxi/atel :00 / u,strea/ fro/ the hea)wor(s of the"ahughat 4)ro,ower Project being constructe) b !e,al lectricit Authorit.

$,,er "ahughat 4)roelectric Project is a casca)e )e-elo,/ent ,roject an) )oes not ha-e a/otorable access roa) at ,resent. The nearest roa)hea) to this ,roject is an earthen roa) at=ha,sin)a)a originating fro/ &aleshor. This roa) is about (/ long. &aleshwor lies about *





(/ north of 'eni on the 'eni % 3o/so/ roa). 'eni the )istrict hea) >uarter of 7ag)i Districtis accessible b a 1* (/ long gra-el roa) that originates fro/ 7al Dhunga on Po(hara 'aglung4ighwa. About 20 (/ of access roa) will be re>uire) to reach the hea)wor( site fro/ the

nearest roa) hea) at 7auwa,hant. Si/ilarl a,,roxi/atel ; (/ of ,roject roa)s will also bere>uire) for this ,roject.

1+5 !%ope and O&e%ti*e

Tun)i Power Co/,an has entruste) A,ex nerg P-t. Lt). to carr out the full sco,e of thestu)ies inclu)ing the to,ogra,hical sur-e surface geological in-estigation h)rologicalstu)ies an) the initial en-iron/ental exa/ination of this ,roject. The Feasibilit Stu) "e,ortinclu)es the results of the to,ogra,hical sur-e an) /a,,ing the results fro/ the relate)h)rological an) geological stu)ies an) the o-erall )esign of the ,roject at the feasibilit le-el of stu).

The feasibilit le-el )esign of the ,roject thus inclu)es the following

• To,ogra,hical Sur-e an) the ,re,aration of the /a,s• 4)rological stu)ies• Surface geological /a,,ing an) geological stu)ies• Pre,aration of the o-erall ,lan an) conce,t of the ,roject• Feasibilit le-el )esign of the in)i-i)ual structures• sti/ation of ,ower an) energ generation• Cost esti/ation• Construction ,lanning an)• Project e-aluation

1+? Pro&e%t 8e*elopment !trate#y

The ,roject site of $,,er "ahughat 4)roelectric Project is bestowe) with a high hea)/o)erate )ischarge an) /o)erate geological con)itions. As /entione) earlier this ,roject islocate) -er close to the h)ro,ower ,roject being )e-elo,e) b !e,al lectricit Authorit.

!A has alrea) initiate) the i/,le/entation of this ,roject. A,art fro/ these two ,rojectsanother h)ro,ower ,roject on the "ahughat "i-er is also being stu)ie) in the -icinit. t is

(nown as "ahughat E 7angale 4)ro,ower Project an) is license) to an PP. This ,roject liesi//e)iatel u,strea/ of $,,er "ahughat 4)roelectric Project. The hea)wor( of this ,rojecthas been ,ro,ose) to be locate) at a ,lace) calle) Dhar an) the ,owerhouse has been ,ro,ose)on the right ban( of 'agar =hola a tributar of "ahughat =hola about 10 / u,strea/ fro/ theconfluence of "ahughat "i-er an) 'agar =hola an) also the hea)wor(s of $,,er "ahughat4)roelectric Project. Thus it can be seen that $,,er "ahughat 4)roelectric Project is situate)i//e)iatel a)jacent to an) in between two h)ro,ower ,rojects "ahughat E 7angale4)ro,ower Project on the u,strea/ si)e an) !A "ahughat 4)ro,ower ,roject on the)ownstrea/ si)e.

Due to the -irtue of the location of this ,roject $,,er "ahughat 4)roelectric Project can be

)e-elo,e) in two was one as an in)e,en)ent ,ower ,roject with an in)e,en)ent hea)wor(salong the "ahughat "i-er an) the secon) as a casca)e ,roject of "ahughat E 7angale4)ro,ower Project. f )e-elo,e) in the secon) wa the tail water of "ahughat E 7angale4)ro,ower Project will nee) to be )i-erte) into the hea)race tunnel of $,,er "ahughat





4)roelectric Project b constructing an interconnection sste/ at the ,owerhouse of "ahughat7angale 4)ro,ower Project at 'agar =hola. This sche/e will not nee) the construction of ase,arate hea)wor(s an) )esan)ing basin. 4owe-er in or)er to collect the )ischarge fro/ 'agar

=hola a s/all )i-ersion weir an) an inta(e will be nee)e) in a))ition to the other regular structures.

Since )e-elo,ing this ,roject as a casca)e sche/e will ha-e higher financial benefits thisfeasibilit stu) has been un)erta(en as a casca)e )e-elo,/ent of "ahughat E 7angale4)ro,ower Project with the inclusion of the annual flows fro/ 'agar =hola. n this wa the

,roject cost has been significantl re)uce) while /aintaining the sa/e >uantu/ of energgeneration.

1+. !tudy )(e%ution

The )es( stu) ,re,are) for the ,roject was re-iewe) to un)erstan) the basic features of the ,roject ,rior to the -isit to the site. Subse>uentl a site -isit was con)ucte) b a tea/ of ex,erts)uring the /onth of Februar 200< to exa/ine the to,ogra,hical geological an) h)rologicalfeatures of the site. All ,ossible align/ents location of ,roject structures an) other i/,ortantas,ects of the ,roject features were obser-e). 'ase) on these obser-ations an) the generalre>uire/ents of the stu) to,ogra,hical sur-e re>uire/ents were )eci)e).

The to,ogra,hical sur-e of the ,roject area was co//ence) i//e)iatel an) the sur-e /a,s

were ,re,are) accor)ingl.

Following the co/,letion of the ,re,aration of the /a,s h)rological an) geological stu)ies of the ,roject were carrie) out. This was followe) b a full fle)ge) feasibilit stu) of the ,rojectinclu)ing the engineering an) h)raulic )esigns ,re,aration of the costruction sche)ule an) thecost esti/ate of the ,roject. A financial analsis of the ,roject was finall carrie) out to chec( the financial -iabilit of the ,roject.

This Feasibilit Stu) "e,ort has been organi9e) as shown below

Cha,ter 1 ,ro-i)es an intro)uction to the stu) bac(groun) sco,e of wor( an) also ,resents the organi9ation of the re,ort

Cha,ter 2 ,resents the )escri,tions regar)ing the ,roject area an) its location

Cha,ter * ,resents the )etails regar)ing the to,ogra,hical sur-e an) /a,,ing carrie) outfor the ,roject

Cha,ter + ,resents the h)rological stu)ies carrie) out for the ,roject

Cha,ter ,resents the se)i/ent stu)ies carrie) out for the ,roject

Cha,ter ,ro-i)es the geological )etails inclu)ing the )etails regar)ing the geological/a,,ing carrie) out for the ,roject





Cha,ter : )iscusses the alternati-es consi)ere) for the )esign of the ,roject

Cha,ter ; ,resents the o,ti/i9ation stu)ies carrie) out for the ,roject

Cha,ter < ,resents the )escri,tion of the basic ,roject laout the locations si9ing an)interfaces of the in)i-i)ual ,roject co/,onents inclu)ing the )esign conce,tscriteria etc.

Cha,ter 10 ,resents the ,ower e-acuation stu) carrie) out for the ,roject.

Cha,ter 11 )eals with the co/,utations of the out,uts an) relate) benefits fro/ the ,roject

Cha,ter 12 ,resents the construction ,lanning acti-itiesCha,ter 1* ,resents the en-iron/ental stu) carrie) out for the ,roject

Cha,ter 1+ )eals with the esti/ate) cost for the ,roject basis for the calculation of the ratesan) other issues relate) to the cost esti/ate of the ,roject.

Cha,ter 1 shows the )isburse/ent sche)ule.

Cha,ter 1 ,resents the e-aluation of the ,roject inclu)ing the econo/ic in)icators such asthe '?C "atio "" etc.

Cha,ter 1: ,resents the conclusions an) reco//en)ations.

'nne(es

Annex A To,ogra,hic Sur-eAnnex ' 4)rological an) se)i/entation Stu)iesAnnex C #,ti/i9ation of Design DischargeAnnex D Project DesignAnnex Power -acuation

Annex F Project nerg 'enefit Co/,utationAnnex & T#" for nitial n-iron/ental xa/inationAnnex 4 Cost sti/ationAnnex Financial -aluation

The feasibilit re,,ort is )i-i)e) into three -olu/es an) are as follows

5olu/e #ne 7ain "e,ort5olu/e Two Drawings5olu/e Three Annexes




Upper Rahughat Hydroelectric Project !escriptionof Project Area

2+0 8)!CR:PT:ON OF PRO@)CT 'R)'

2+1 >eneral

!e,al lies in the la, of the highest areas of the &reat 4i/alaan "ange. t exten)s fro/ the"e,ublic of n)ia in the south to the high Tibetan Plateau of the Peo,leHs "e,ublic of China in

the north. t is roughl rectangular in sha,e. !e,al e/braces within itself a uni>ue -ariet of geogra,hical settings ranging fro/ the southern lowlan)s at a,,roxi/atel 00 /asl to thehighest ,ea(s in the worl) in its northern ,arts. 'etween these /arginal 9ones there are threerichl -arie) regions na/el the Terai "egion in the south the 7i))le 4ill "egion in betweenan) the Trans 4i/alaan "egion in the north.

2+2 o%ation

The stretch of "ahughat =hola ,ro,ose) for the )e-elo,/ent of the ,roject lies along a -erstee, ,art of this ri-er.

"ahughat "i-er is a /ajor tributar of =ali &an)a(i "i-er an) /eets the =ali &an)a(i "i-er near the ,lace calle) &aleshwor of &hatan 5DC. The ,roject site lies between latitu)es of 2;02J+K an) 2;02;J*0 !orth an) between longitu)es ;*0*0J00K an) ;*0*1J0K ast.

2+ Physi%al Features

#wing to the three richl -arie) regions !e,al lies in an area with a great )ifference inele-ation fro/ the north to the south. As a result !e,al ex,eriences an exce,tional -ariation incli/ate. Fro/ south to north fi-e )efine) cli/atic 9ones exist in the countr these are

• Tro,ical• Subtro,ical• Te/,erate• Al,ine• Sub Arctic

The )o/inant cli/atic influence is that of the south east /onsoon. The cli/ate of the &an)a(i'asin is influence) b the ,hsiogra,h of the region. The )ifference between the war/ hu/i)su//er an) the se-ere col) winter beco/es /ore /ar(e) with the increase in altitu)e. The

south east /onsoon is res,onsible for al/ost all of the rainfall in the basin. The /onsoon startsin /i) 3une an) continues until late Se,te/ber. This is followe) b a )r ,erio) an) the winterwhich starts in !o-e/ber an) lasts until Februar. A short winter rainfall characteri9es the


Chapter Two

8)!CR:PT:ON OF T$) PRO@)CT 'R)'



Upper Rahughat Hydroelectric Project !escriptionof Project Area

winter. The cli/ate beco/es ,rogressi-el war/er fro/ 7arch until the beginning of the next/onsoon.

2+5 '%%essiility

$,,er "ahughat 4)roelectric Project is a run%off%ri-er ,roject an) )oes not ha-e a /otorableaccess roa) at ,resent. The nearest roa)hea) to this ,roject is an earthen roa) at =ha,sin)a)aoriginating fro/ &aleshor. This roa) is about (/ long. &aleshwor lies about * (/ north of 'eni on the 'eni % 3o/so/ roa). 'eni the )istrict hea) >uarter of 7ag)i District is accessible

b a 1* (/ long gra-el roa) that originates fro/ 7al Dhunga on Po(hara 'aglung 4ighwa.About 20 (/ of access roa) will be re>uire) to reach the hea)wor( site fro/ the nearest roa)hea). 4owe-er if the access roa) u, to the hea)wor(s site of the "ahughat 4)roelectricProject being i/,le/ente) b !A is built earlier onl about 2 (/ of access roa) will nee) to

be built to reach the ,owerhouse site of this ,roject.




Upper Rahughat Hydroelectric Project Topographical Sur"ey and #apping

+0 TOPO>R'P$:C' !"RV)A 'N8 M'PP:N>

+1 :ntrodu%tion

The sur-e wor(s for the ,ro,ose) ,roject were con)ucte) fro/ /i) 7arch to the en) of A,rilin the ear 200<. Pro,er sur-e an) le-eling wor(s are necessar to )esign the co/,onents to

,re,are )rawings an) to calculate the >uantities of the ,roject co/,onents. The sur-e )atagreatl influences the >ualit of )esign. Therefore all the sur-e wor(s were carrie) out

,recisel an) correctl.

+2 !%ope o7 9or/

The sur-e wor(s were carrie) out with the objecti-e of ,re,aring /a,s of the hea)wor(s areainta(e site )esan)er area tunnel align/ent ,owerhouse an) tailrace sites at a,,ro,riate scalesto enable structural laouts to be ,re,are). The following wor(s were ,erfor/e) )uring this

,hase of sur-e

• All the sur-e wor(s were un)er ta(en using $T7 co%or)inates an) ele-ations carrie)out fro/ existing control ,oints.

• Close tra-erse sur-e was carrie) out to establish re>uire) groun) control ,oints at-arious locations in the ,roject area.

• All the /ajor groun) control ,oints were /onu/ente) with /ar(e) on ,er/anent boul)ers.

• To,ogra,hical /a,s of hea)wor(s inta(e )esan)er surgetan( ,owerhouse an) tailrace

sites were ,re,are) in a,,ro,riate scales.

• Different cross%sections of "ahughat "i-er were ta(en at e-er 100 / inter-al.

+ '*ailale :n7ormation and 8ata

The infor/ation a-ailable for carring out the feasibilit stu) of $,,er "ahughat 4)roelectricProject is as follows

i. To,ogra,hic 7a,s fro/ the De,art/ent of Sur-e To,ogra,hic Sur-e 'ranch.Scale 12000Sheet !o 2;;* 11A

ii. Digital )ata of To,o sheet 2;;* 11Aiii. Project )entification re,ort ,re,are) b the client.


Chapter Three

TOPO>R'P$:C' !"RV)A 'N8 M'PP:N>




+5 >eneral

The senior sur-eor an) a tea/ of sur-eors carrie) out the )etaile) to,ogra,hical sur-e of theselecte) sche/es. All the )ata necessar to )eter/ine the locations coor)inates an) le-els wereobtaine) b )irect /easure/ent in the fiel). To achie-e the re>uire) accurac an) stan)ar)sPentax "*2M an) =oli)a =TS ++0 total stations with least count of were use).

+? Methodolo#y

The /etho)olog use) for the entire sur-e wor(s was )e-elo,e) as ,er the sco,e of wor(swhich inclu)es )es( stu) reconnaissance sur-e an) /onu/entation of control ,oints controltra-ersing hori9ontal an) -ertical control an) to,ogra,hic sur-e.

+?+1 8es/ !tudy

Prior to the fiel) sur-e )es( stu) was carrie) out b using the /ost recent to,ogra,hical /a,sBScale 12000. Detaile) infor/ation about the ,roject area for the sur-e wor( was note).Finall all the a-ailable ,lans ,rofiles an) location /a,s ,re,are) )uring the ,re%feasibilitstu) were collecte).

+?+2 Re%onnaissan%e !ur*ey

After finali9ing the )es( stu) a tea/ of /ulti%)isci,linar ex,erts were /obili9e) for fiel)-erification. After finali9ing the ,roject site an) before the )etaile) sur-e wor( a brief reconnaissance sur-e was carrie) out with flagging at necessar ,oints aroun) the entire ,rojectarea to be /a,,e). All the flagging ,oints were /ar(e) b rea) ena/el ,aint. The first ste, of the sur-e was to fix the control ,oints aroun) the ,roject area with res,ect to existingto,ogra,hical /a,s.

+?+ Monumentation o7 >round Control Points

All the /ajor control ,oints were /a)e cons,icuous in the fiel) b /onu/entation of control ,oints with an iron ,in set in roc( or boul)er or with crosses chisele) on the boul)ers. The werealso /a)e noticeable in the fiel) b /ar(ing with re) ena/el ,aint. Altogether ,er/anent

bench/ar(s were establishe) at the ,roject area a/ong which three bench/ar(s T% T%A an)T%' were establishe) at the ,owerhouse site an) * bench/ar(s '7%1 '7%2 an) '7%* wereestablishe) at hea)wor(s site. Descri,tion car) of each of the control ,oints will be gi-en inAnnex A*.

+?+5 Control Tra*ersin#

The basic control tra-erse sur-e was carrie) out fro/ existing control ,oints RK52 and RK

55 establishe) b !A at its hea)wor(s site with the following -alues of coor)inates an)ele-ations in $T7 coor)inate sste/





Tale 1 ist o7 asi% Control Points

!+No+ BNorthin# A)astin# )le*ation Remar/s

"=%+2 *1++<::.2+: +*:11.< 120*.1 stablishe) b !A

"=%++ *1+0*;.;< +*+.2: 12*.< stablishe) b !A

A close) tra-erse was carrie) out fro/ ,owerhouse site to hea)wor(s site. Then se-eral another

re>uire) control ,oints were establishe) b con-entional tra-erse sur-e co-ering the entire areato be /a,,e) fro/ the hea)wor(s site to the ,owerhouse site.

Tale 2 Coordinates and ele*ation o7 tra*erse points

!tation BNorthin# A)astin# )le*ation Remar/s

C=+ *1+2:0.0: +++02.*: 1*.: Powerhouse SiteC=+: *1+;:.;2: +++0<.110 1:2<.0*+ Powerhouse Site

C=+< *1+<:.1< +*<*:.;*2 1;;+.0:C=0 *1+:102.;** +*::+.;: 1;:.10C=1 *1+:1::.**; +*:1.;<2 1;;0.:01C=2 *1+:1<0.;0+ +*:0+.;2 1;;+.C=* *1+:22:.20 +*<2.+: 1;;;.<2;C=+ *1+:<2.0: +*2:1.0+; 1;0.0C= *1+;02.2+ +*2:.+2 1;0.:0C= *1+<21.;:; +*1:.1<0 1;0.0 4ea)wor(s SiteC=: *11112.;+ +*1++.:*0 1:.:: 4ea)wor(s Site

C=:A *10<<*.*0 +*220.*20 1:+;.*:0 4ea)wor(s SiteC=A *1+<1;.++ +*1:1.2+ 1;0.:C=A *1+;01<.< +*2::.1:: 1;0:.2:C=+A *1+:<<.<1 +*2:1.+2: 1;0;.+1*C=*A *1+:22+.<:2 +*;:.<++ 1;;<.+10C=2A *1+:1<*.:0* +*<:.<: 1;;+.::C=1A *1+:1:;.<1: +*:0:.;* 1;;0.;12C=0A *1+:101.+: +*:<.;* 1;:.:;C=+<A *1+<.1+0 +*<*2.20 1;;+.2:

C=+;A *1+;:+.1; +++22.< 1:*.;2:C=+:A *1+2<;.<2* +++;0.2*0 1:.12C=+A *1+1.+<; +++1:.2+ 1*0.+12





All tra-erses for/e) b the con-entional sur-e were close) loo,s or close) on existing tra-erse ,oints. The tra-erse legs were /a)e as long as ,ossible an) a fixe) tri,o) sste/ was use) for all reflecting ,ris/s to achie-e better accurac. The tra-erse networ( is gi-en in Annex A1.

The sub%tra-erses were carrie) out using the starting an) closing bearing of the ,ointsestablishe) fro/ the /ain tra-erse. All the offset ,oints were establishe) b carring out thetra-erse sur-e fro/ two /ain control ,oints where-er necessar.

+?+? $oriontal and Verti%al Control

The control ,oints were establishe) b the tra-erse /etho). The tra-erse was con)ucte) alongthe left ban( of "ahughat "i-er an) then close) to the (nown station co-ering the necessar areaof the hea)wor(s site an) ,owerhouse area. =oli)a Total Station with a least count of Q wasuse) for /easuring hori9ontal an) -ertical angles. #ne co/,lete set of hori9ontal an) -erticalangles were obser-e) )uring the control tra-ersing.

For hori9ontal control the following /easure/ents were ta(en

% 7ean angle an) )istance co/,utation was chec(e) ,recisel.

% Angular closure was chec(e) for close) loo,s.% A9i/uth was chec(e) between tra-erse ,oints% Angular /isclosures were a)juste) an)% RM an) R6 were co/,ute) for ,lani/etric closure.

n the tra-erse sur-e the hori9ontal angles were obser-e) in one co/,lete roun) within a /eanof 1Q. Distance was /easure) in the fore an) bac( sights )irections an) the /ean )istancea)o,te). The closing errors were )istribute) accor)ing the co//on sur-e stan)ar)s.

Altogether 2; control ,oints were establishe) in the /ain%tra-erse line 12.< (/ in length.Si/ilarl 1< offset ,oints were establishe) where-er necessar aroun) the ,roject area.

For -ertical control the following /easure/ents were ta(en

% Co/,utation for ∑ 'ac( sight ∑ Foresight an) ∑ Difference of height were chec(e) ,recisel.

% Co/,utation of Rh for each loo, was chec(e) an)% All the loo,s were a)juste) b the Dell /etho) so as to ,ro-i)e consistent heights for

use in s,ot sur-eing.

8hile sur-eing a tra-erse line all angles an) )istances were /easure) b a,,ling the force

centering /etho). Distance /easure/ent was ,erfor/e) using Pentax an) =oli)a total stationswith stan)ar) reflecting ,ris/ with an accurac of // ,,/. 'oth bac( sighting an) foresighting of )irect )istance were /easure). A reasonable closing error was achie-e).

Tundi Power Company ! Apex Energy Pvt. Ltd.




+. 8ata Pro%essin#

All the sur-e )ata were co/,ute) in the fiel) as well as in the =ath/an)u office. Si/ilarlso/e fiel) )ata were e-aluate) an) hori9ontal )istances an) ele-ations were calculate)reci,rocall. All the coor)inates an) ele-ations of each station an) sur-e ,oint were thenco/,ute) with res,ect to the gi-en $T7 coor)inates an) ele-ation of the control ,oint RK52

and RK55 establishe) b !A. After co/,letel chec(ing the )ata entr /a,,ing Softwarewas use) for /a, ,re,aration. Finall the to,ogra,hic /a, was ,re,are) in AutoCAD 200:for/at.

+4 8etailed Topo#raphi%al !ur*ey

The features of ht terrain were sur-ee) b /eans of s,ot sur-eing. S,ot ,ositions were ta(en b the tacho/etric /etho) fro/ )ifferent tra-erse ,oints. naccessible ,oints li(e roc( faces to,of cliff lan)sli)e e)ge etc. were sighte) fro/ at least two (nown ,oints b rea)ing both thehori9ontal an) -ertical angles.

Features such as ri-erban(s high floo) le-el lan)sli)es cliff house culti-ate) lan)s roa)scanal e/ban(/ent boul)ers etc. were recor)e).

The to,ogra,hical sur-e an) le-eling wor(s were carrie) out for hea)wor(s site )esan)er areainta(e site surge tan( area ,enstoc( route align/ent an) the ,owerhouse an) tailrace sites.

+6 Mappin#

The )etaile) to,ogra,hical /a,,ing of hea)wor(s inta(e )esan)er hea)race tunnel surge tan( ,enstoc( alig/ent ,owerhouse an) tailrace area were carrie) out in the re>uire) scale as gi-en below.

Pro,ose) 4ea)wor(s site Scale 11000 ; sheets BA* si9ePro,ose) Powerhouse Site Scale 12000 Sheets BA* si9eProject Laout 7a, Scale 110000 2 sheets BA* si9e

All the /a,s ,rescribe) abo-e were ,re,are) in the scales as /entione) in the sco,e of wor(.Altogether 0 ha of lan) was co-ere) in the groun) sur-e at hea)wor(s site an) about +0 ha atthe ,owerhouse site. All the to,ogra,hical /a,s are gi-en in Annex A1 in a,,ro,riate scales.

+- Ri*er Cross !e%tions

Se-eral cross%sections of the "ahughat "i-er an) 'agar =hola were ta(en for h)rologicalstu)ies. Altogether 1 cross%sections of 'agar =hola were ta(en at hea)wor(s site an) ; sections

Tundi Power Company # Apex Energy Pvt. Ltd.




were ta(en at ,owerhouse site. All the ri-er cross%sections are ta(en at 100 / inter-al an) allsection )ata will be gi-en in Annex A2.

+10 'nne(es

All the To,ogra,hical /a,s ri-er cross%section )ata an) )escri,tion car)s of ,er/anent bench/ar(s are gi-en in following Annexes

Annex A%1 To,ogra,hical 7a,sAnnex A%2 "i-er Cross%section Data

Annex A%* Descri,tion Car)s of Per/anent 'ench/ar(s




Upper Rahughat Hydroelectric ProjectHydrological Studies

5+0 $A8ROO>:C' !T"8:)!

5+1 Physio#raphi%al Chara%teristi%s o7 the alephi asin

5+1+1 Ri*er and Cat%hment Chara%teristi%s

The "ahughat =hola constitutes one of the /ajor tributaries of =ali &an)a(i an) the =ali&an)a(i is one of the /ajor ri-ers of the Sa,ta &an)a(i 'asin. The "ahughat 'asin is locate) in

between latitu)es 2;o 22 an) 2;o +2 ! an) longitu)es ;*o * an) ;*o 2: an) lies in 7ag)iDistrict of 8estern De-elo,/ent "egion.

The "ahughat =hola catch/ent is bor)ere) b Dhaulagiri range to the north =ali &an)a(i"i-er 'asin to the east 7ag)i ri-er basin to the west an) /i))le hills to the south. Thecatch/ent area of "ahughat =hola an) 'agar =hola is shown in the satellite i/age below.

The snow co/,onent in the ri-er flow /a(es it a ,erennial ri-er with sustaine) )r season flow.The u,,er ,art of the catch/ent has large glaciers which contribute to sustaine) flow )uring the)r season.

The hea)waters of "ahughat =hola flow north%south fro/ the 4igh 4i/alaan "ange through)ee,l incise) gorges. The ri-er originates fro/ the Dhaulagiri "ange an) its catch/ent area is


Chapter Four

$A8ROO>:C' !T"8:)!




/ountainous with a wi)e -ariation in ele-ations ranging fro/ ;1: / BDhaulagiri Pea( an)100 / at weir site. The Sani =hola a /ajor tributar of "ahughat =hola originates at aboutl. :2; /. //e)iatel )ownstrea/ of the Sani%"ahughat =hola confluence lies the ,ro,ose)

weir site of "ahughat 7angale 4)roelectric Project. The other /ajor tributar 'agar =holaoriginates at an ele-ation of about l. +:: /. The ,ro,ose) ,owerhouse site of "ahughat7angale 4)roelectric Project lies on the right ban( of 'agar =hola about 20 / u,strea/ of the confluence with "ahughat =hola.

t is ,ro,ose) to )i-ert the tailwater of "ahughat 7angale 4)roelectric Project an) also ta,a))itional flow fro/ 'agar =hola b constructing a weir across 'agar =hola at this location.The ,ro,ose) weir site is locate) at about l. 100 /.

The catch/ent area is characteri9e) b )ee, gorges. The basin ,hsiogra,h ranges fro/ higher to lesser 4i/alaas. The total )rainage area of 'agar =hola at the ,ro,ose) weir site of $,,er "ahughat 4)roelectric Project is about + (/2. The catch/ent area at the ,ro,ose)

,owerhouse site of $,,er "ahughat 4)roelectric Project is about *12 (/2 out of which 202(/2 is below l. *000 /. The a-erage gra)ient of the ri-er in between the ,ro,ose) weir sitean) ,owerhouse site is about ;.0 O.

The ,ro,ose) ,owerhouse site of $,,er "ahughat 4)roelectric Project lies at *1+00 !orthing an) +*:00 asting on the left ban( of "ahughat =hola an) locate) .0 (/)ownstrea/ of the ,ro,ose) weir site an) about . (/ u,strea/ of the =ali%"ahughatconfluence.

All of the abo-e /entione) )rainage areas ha-e been esti/ate) base) on the latest 10000 an)12000 scale to,ogra,hical /a,s co/,ile) fro/ aerial ,hotogra,h of 1<< b the Sur-eDe,t.

5+1+2 The Climate

As is t,ical of watershe)s of !e,al the "ahughat 'asin co-ers a wi)e range of cli/ates.Cli/atic con)itions of "ahughat =hola basin -ar with altitu)e. Substantial )ifferences occur o-er -er short )istances an) are strongl influence) b altitu)e. Two )istinct /eteorologicalregions exist in the basin. The basin at the u,,er reaches is surroun)e) b high /ountains thusha-ing an al,ine cli/ate. The lower catch/ent below l. 2000 / has a te/,erate an) also war/cli/ate in the region.

The "ahughat =hola basin ex,eriences the effects of the n)ian southwest /onsoon. The onsetof /onsoon co//ences fro/ 3une till Se,te/ber occasionall exten)ing to /i) #ctober.During this ,erio) relati-e hu/i)it is at their /axi/u/ high te/,eratures are less extre/eco/,are) to the ,erio) i//e)iatel ,rior to the /onsoon an) the rainfall a/ounts toa,,roxi/atel ;0O of the annual rainfall.





The 4igh 7ountain "ange in the north essentiall for/s a barrier forcing the /onsoon broughtabout b orogra,hic effects to ,our )own south of this range. "ainfall intensit -aries

throughout the basin accor)ing to the )egree of ex,osure with /axi/u/ intensities occurring onthe south facing slo,es. "ainfall intensit also -aries in the catch/ent with ele-ation. n generalthe a/ount of ,reci,itation is highest in the south at the lower ele-ations an) gra)uall)ecreases to the north with increase in ele-ation.

8inter ,reci,itation in the region is s,arse an) falls as snow on the higher ,ea(s. The ,erio)fro/ #ctober to !o-e/ber re,resents a general cli/atic transition to winter con)itions. "ainfallis rare )uring this ,erio). Fro/ the en) of 3anuar until 7a the region beco/es ,rogressi-elwar/er. The ,er/anent snow line is at l. 000 /. Fro/ 7arch onwar)s the snow line shiftsu,war)s resulting in a gra)ual increase in ri-er flows )ue to snow/elt.

7onthl rainfall su//aries an) cli/atological )ata were collecte) fro/ the De,art/ent of 4)rolog an) 7etereolog BD47. There is a rainfall station at 'ega 5illage to the easta)jacent to "ahughat =hola basin at l. 1::0 / which shows annual a-erage ,reci,itation 20;*// an) 1 )a /axi/u/ rainfall of 1+< //. Another rainfall station to the north Lete islocate) in the a)jacent basin of =aligan)a(i at l. 2*;+ / an) its recor)s show an a-erageannual ,reci,itation of about 12+* //.

The nearest /eteorological station re,resentati-e to the ,roject area is locate) at 'eni 'a9aar l;* / Latitu)e 2;o 21 ! an) Longitu)e ;*o *+ . The /ean annual ,reci,itation recor)e) atthis station is 10 // an) the /onsoon ,reci,itation is about 1*00 //.

Tale 5 Monthly 8ata 7or Temperature and Relati*e $umidity,

eni !tation, :nde( No+ 0.0-

'ir Temperature

<oC=

Relati*e $umidity

<D=

)(treme Ma( )(treme Min@anuary 2*.2 *.1 :*Feruary 2.0 .2 :0Mar%h **.1 :.< 0'pril *.1 11.1 May *:.1 1.0 :0@une *.1 1.1 ;@uly **.0 1<.2 ;'u#ust **.* 1;.1 ;!eptemer **.0 1:.1 ;O%toer *1.1 12. ;1No*emer *0.0 ;. :8e%emer 2*.0 .0 ::'nnual 4+1 +1 4.





The catch/ent area at the ,ro,ose) )a/site lies in the te/,erate region. The ,roject areaex,eriences war/ an) wet cli/ate )uring 3une to Se,te/ber an) col) cli/ate )uring !o-e/ber

to A,ril. Figure +%1 an) Figure +%2 below show the -ariation of long ter/ /ean /onthl ,reci,itation at Lete an) 'ega o-er the ear.

Fi#ure 51 Mean Monthly Rain7all at ete





Fi#ure 52 Mean Monthly Rain7all at e#a

5+2 !tream Flows

5+2+1 asi% $istori% 8ata

There are fi-e gauging stations that ha-e been consi)ere) to esti/ate the flows at the ,ro,ose)weir site at $,,er "ahughat 4)roelectric Project.

• 7o)i =hola at 3ha,hre 'agar St. !o +0.• Seti =hola at &ahachow( St. !o +2:

• Seti !a)i at Patan Da/auli St. !o +*0.• 7a)i !a)i at Sishaghat St. !o +*;• "ahughat =hola at 3hi St. !o. +0+

7o)i =hola Seti an) 7a)i originate fro/ the Anna,urna 4i/alaan "ange. "ahughat =holaoriginates fro/ the Dhaulagiri "ange. 4ence the ,hsiogra,hic characteristics of these four

ri-ers are si/ilar to each other. The h)rological )ata of the fi-e gauging stations B+0. +2:+*0. +*; an) +0+ are use) to assess the flows of 'agar =hola at the weir site. Table +%+ showsthe characteristics of the strea/ gauge stations use) for analsis. The satellite i/ager belowalso shows the si/ilar ,hsiogra,hic characteristics.

Tale 55 Chara%teristi%s o7 !tream#au#e !tations <!our%e3 8$M=

>au#e !ite!tn

Code

'rea

</m2=

'nnual

Flow

$ypsometri% 8ata

Km2

Period

Re%ord

B/*?s U*000/ U000/7o)i =hola +0. +: 2.: *+ +2 1<<+%200

Seti =hola +2: **+ *. 1* 2;: 2000%200+





Seti !a)i +*0. 1*0 1* 1120 1*0* 2000%200+

7a)i !a)i +*; ;:< :0.< 00 ;0+ 1<<*%2001

"ahughat =hola +0+ *2 +0. 202 *20 2000%200

5+2+2 Methodolo#y

5+2+2+1 Re#ional 'nalysis 'pproa%h

A regional analsis a,,roach was ta(en to assess the long ter/ /ean /onthl flow at the inta(esite of "ahughat 7angale 4)roelectric Project. The result of the sa/e regional analsis wasalso use) to assess the flows of "ahughat =hola at the 'agar%"ahughat confluence. The)ifference between the flows of "ahughat =hola at 7angale an) at the 'agar confluence gi-esthe flow esti/ate contribute) b the inter/e)iate catch/ent. The /ean )ail flows of 'agar =hola at ,ro,ose) weir site are esti/ate) b the following e>uation.

Ea#ar E:nt ( <'reaa#ar;'rea:nt=

8here'agar is the esti/ate) flow of 'agar =hola

nt is the esti/ate) flow fro/ the inter/e)iate catch/entArea'agar is the catch/ent area of 'agar =hola + (/2Areant is the catch/ent area of the inter/e)iate catch/ent < (/2





' is a factor which -aries fro/ /onth to /onth an) is obtaine) using the(nown /onthl flows an) catch/ent areas at 7angale an) 'agar confluence.

Accor)ing to the h)rolog re,ort of "ahughat 7angale 4)roelectric Project the long ter//ean /onthl flows of the fi-e gauging stations B+0. +2: +*0. +*; an) +0+ were ,lotte)against their corres,on)ing total catch/ent areas on a log%log scale. Plots were /a)e for each/onth of the ear B3anuar to Dece/ber. The a-ailable long ter/ /ean /onthl flows for eachgauging station are gi-en below in Table +%.

Tale 5? on# Term Mean Monthly Flows

Ri*er Modi Khola !eti Khola !eti Nadi Madi Nadi Rahu#hat

@an 11. .<1 22.: 1.** :.+

Fe 10.12 .++ 1<.1; 1*.0 .Mar <.;; .:; 1:.2; 1+.<1 .2+'pr 12.0 <.0 20.: 1;.< <.:May 20.:; 1:.* +:.* *0.20 22.:+@un :1.*0 +1.+ 1:;.1 <*.;; +:.:2@ul 201.< 11.1 +0*.0: 1;;.+ 10:.'u# 1<;.01 10<.+1 +1.+ 222.+2 12+.!ep 1*.<0 :;.0+ 2:;.1 1+*.;+ :;.*;O%t +0.+; 2.2; 112.*: <.+ 2.2No* 2*.<; 1*.0 2.<1 2<.2+ 1+.:*

8e% 1.+ ;.<< *0.*: 20.* <.*'nnual 2.: *.1 1*.1< :0.;< *:.:0

The relationshi,s obtaine) between the long ter/ /ean /onthl flows an) the catch/ent areasfor each /onth are shown below in the following figures.









Tundi Power Company 1! Apex Energy Pvt. Ltd.




Tundi Power Company 1# Apex Energy Pvt. Ltd.




The )eri-e) regional relationshi, between the catch/ent area an) the long ter/ /ean /onthlflows for each /onth )escribe) b regression e>uations are gi-en in the abo-e figures alongwith their corres,on)ing coefficient of correlation " 2

8here 6 V long ter/ /ean /onthl flow in /*?s an) M V )rainage area in (/2.

The " 2 for all the abo-e relationshi,s are /ore than 0.; which show a goo) fit between the )ata ,oints an) hence the regression e>uations can gi-e reliable results.

The abo-e regression e>uations were use) to esti/ate the long ter/ /ean /onthl flow at theinta(e site of "ahughat 7angale 4)roelectric Project an) at 'agar%"ahughat =hola

confluence. The catch/ent area at the inta(e site of "ahughat 7angale 4)roelectric Project isesti/ate) to be 1 (/2. The catch/ent area at 'agar%"ahughat =hola confluence is about 22(/2. Therefore the inter/e)iate catch/ent is < (/2.





Table +% shows the )eri-e) long ter/ /ean /onthl flows at the inta(e site of "ahughat7angale 4)roelectric Project an) at 'agar%"ahughat confluence. The long ter/ /ean /onthlflows for the inter/e)iate catch/ent is also gi-en as well as the calculate) factor ' for each

/onth.

Tale 5. on# Term Mean Monthly Flows

@an Fe Mar 'pr May @un @ul 'u# !ep O%t No* 8e%

a#ar

%on7luen .0 .1 .2 ;.+; 1.*< *.+; ;<.< <*.* 0.00 1<.<* 11.1: :.*Man#ale

:nta/e +.0< *. *.1 +.+ 10.2: 22.;0 .2< +.: +2.<1 12.:2 .<0 +.:nter

Cat%hm 2.1 1.; 2.+ *.;+ .12 12.; 2*.*0 2;.< 1:.10 :.21 .2: 2.<:Fa%tor

1.0+: 0.;< 1.2* 1.*21 1.02+ 0.<< 0.0 0.;0 0.:* 0.<;+ 1.+00 1.0;0

5+2+ !tream 7low 'nalysis at :nta/e site on a#ar Khola

The /ean )ail flows at 7angale inta(e site were obtaine) fro/ /ean )ail flows of "ahughat=hola at 3hi gauging station b using /onthl con-ersion ratios. The sa/e /etho)olog wasuse) to obtain the /ean )ail flows of "ahughat =hola at 'agar confluence. The )ifference

between the /ean )ail flows at these two sites ga-e the /ean )ail flows for the inter/e)iatecatch/ent. The e>uation )iscusse) abo-e was use) to obtain the /ean )ail flows of 'agar =hola at inta(e site. Table +%: gi-en below shows the esti/ate) /ean /onthl flows of 'agar =hola at inta(e site.

Tale 54 Mean Monthly Flows o7 Rahu#hat Khola at @hi

@an+ Fe+ Mar+ 'pr+

Ma

y @un+ @ul+ 'u#+ !ep+ O%t+ No*+ 8e%+ Aear

:nta/

e 1.*: 1.10 1.1< 1.;0 *.*< :.2 1.2; 1;.;2 11.21 +.0< 2.* 1.0 .:<

5+2+5 Riparian Release

The long ter/ /ean /onthl flow for the )riest /onth Februar at the inta(e site is 1.10/*?sec. As a general ,ractice a flow e>ui-alent to 10O of this /onth i.e. 0.11 / *?sec will berelease) )ownstrea/ as the ri,arian release for fish an) a>uatic life.

5+ Flow 8uration Cur*e

The flow )uration table for the flows at 7angale inta(e site is gi-en in Table +%;.

Tale 56 Time )(%eeden%e o7 8is%har#es at Man#ale 8amsite

Time )(%eeden%e

<D=

8ays per Aear 8aily 8is%har#e )Gualled

Or )(%eeded <m;s=

2 <1 2.;0*0 110 20.*1





* 12; 1+.21+0 1+ 10.:;+ 1+ ;.;+0 1;* :.0 201 .:;0 21< +.<* 2*: +.*<:0 2 *.<: 2:+ *.<;0 2<2 *.+;; *10 *.2<0 *2< *.0;< *+: 2.;

100 * 1.+

The flow )uration cur-e for 'agar =hola was constructe) fro/ the generate) )ail ,rojectinflow ti/e series 2000%200 an) is shown in Figure +%*. The )ail flows )e,en)ing on gi-enti/e excee)ence are also tabulate) in Table +%:.

Tale 5- Time )(%eeden%e o7 8is%har#es at a#ar 8amsite

Time )(%eeden%e <D= 8ays per Aear 8aily 8is%har#e )Gualled

Or )(%eeded <m;s=

2 <1 :.::*0 110 .0:* 12; +.2

+0 1+ *.1+ 1+ *.0*0 1;* 2.+: 201 2.000 21< 1.:1 2*: 1.:0 2 1.+0: 2:+ 1.2<;0 2<2 1.2*; *10 1.1+<0 *2< 1.0;< *+: 0.<<

100 * 0.:

Fro/ the abo-e flow )uration tables the +0O )e,en)able flow at 7angale is 10.; /*?s an) for 'agar =hola is esti/ate) to be *. /*?s gi-ing a total of 1+.+ /*?s. The flow )uration cur-e isshown in Figure +%* an) long ter/ /ean /onthl flows in Figure +%+.





Fi#ure 5 Flow 8uration Cur*e at a#ar :nta/e site

Fi#ure 55 on#term Mean Monthly Flow at a#ar :nta/e site, m;s





5+5 Flood Flows

5+5+1 a%/#round

Te/,orar structures li(e the coffer)a/s will be )esigne) to resist floo) e-ents with a rather short recurrence inter-al e.g. to 20 ears. Designs of ,er/anent structures ha-e to consi)er the 1 in 100 ear to 1 in 10000 ear floo) e-ents )e,en)ing on the ris( in-ol-e). The selectionof the )esign floo) in-ol-es consi)erations as gi-en below

• ffect of o-erto,,ing on the structure

• Cost of structure reconstruction

• Potential loss of life an) cost of )ownstrea/ )a/age

• Cost of loss of re-enue while the structure is out of co//ission

The objecti-e of the floo) analsis was therefore to esti/ate the ,roject inflow floo)s u,to 00ear return ,erio)s. These ,ea( floo) -alues are re>uire) to )eter/ine the s,illwa )esign floo)an) for )a/ stabilit analsis. #wing to the negligible storage ca,abilit of $,,er "ahughat4)roelectric Project infor/ation on the sha,e of the floo) h)rogra,hs is of less i/,ortance.

t is e/,hasi9e) that the ,roject will ha-e a relati-el low )a/ so that a ,otential h)rologicfailure woul) har)l cause catastro,hic conse>uences in ter/s of hu/an life an) consi)erable

loss of ,ro,ert. This is a fact which was ta(en into consi)eration when selecting the return ,erio) for s,illwa )esign floo).

To o-erco/e ob-ious shortages such as the non%a-ailabilit of )ata base at the weir site an) theuncertainties in-ol-e) in the historic )ata series the esti/ation of floo) )ischarges necessitate)a,,lication of a regional floo) fre>uenc analsis.

5+5+2 Re#ional Flood FreGuen%y 'nalysis

A stu) on 7etho)ologies for sti/ating 4)rologic Characteristics of $ngauge) Locations in !e,al B3ul 1<<0 was carrie) out b 8CS an) D47. This stu) uses the a,,roach of "egional Floo) Fre>uenc Analses for floo) stu)ies.

Two /etho)s which were in-estigate) in the abo-e stu) are the in)ex floo) /etho) an) thefre>uenc )istribution ,ara/eter ,re)iction /etho). t was foun) that the in)ex floo) /etho)was not suitable for !e,al because there is not ho/ogeneit throughout the countr. !or/allwhen non%ho/ogeneit is )isco-ere) the region is sub)i-i)e) into s/aller ho/ogeneousregions.

The stu) shows the results fro/ the fre>uenc )istribution ,ara/eter ,re)iction /etho) whichis a -ariation of the /ulti,le regression /etho). The in)e,en)ent -ariable which was foun) to

be /ost significant in all of the regression analses was the area of the basin below le-ation





*000 /. This area re,resents the ,ortion of the basin that is influence) b /onsoon ,reci,itation.

4ence in the following regional analsis the ,ortion of the area falling below l. *000 / isuse). The following regional analsis was carrie) out for the &an)a(i 'asin as "ahughat =holalies in the &an)a(i 'asin.

Annual floo) )ata for 1* gauging stations that lie within &an)a(i 'asin were collecte). Floo)fre>uenc analsis was ,erfor/e) using the co/,uter ,rogra/ CFA;; for each gauging station.Table +%10 below shows the results of fre>uenc analsis for each gauging station an) thecorres,on)ing catch/ent area below l. *000 / for each gauging station.

Tale 510 Re#ional Flood 'nalysis H >anda/i asin

Ri*er

!t+

No+ 2 ? 10 20 ?0 100 200 ?00 1000 10000

'rea

/m2

=ali 510

1;0

2*0 2:10

*00 *10 *;0 +220 +:20 100 00 224

'a)iga) 514

120

1:<0 210

200 2<:0 ***0 *:00 +210 +00 000 1-50

=ali 520

+:0

*0 :0

;:10 10200

11+00

1200

1+100

1**0 1<20 402.

Seti 50 *; 1* ;0* << 12: 10* 1:+; 2100 2*;: *+<+ ?2

7a)i 56 :: ;2 10;01**

0 1:00 2010 2*0 2;:0 **00 00 .00

7arsang)i 5-+6

1*0

1:00 1<0

2210 20 2;+0 *1*0 *+0 *;0 00 120

7o)i 50.+? +< 2: : <22 11:0 1*;0 120 1<<0 2*00 *+0 .5

Trisuli 554

10<0

110 1:<0

200 2+00 20 2<*0 *2;0 *0 +00 650

'urhi &. 55? :;1100

0 11:01*+

0 1;0 1:;0 1<;0 22;0 220 *+*0 42

An)hi 51? +1 ;00 <;011

0 1+00 100 1;00 20;0 2*00 *000 54.

Phalan(hu 55.+6 1 20 *22 +00 2* 2; :++ <1: 10 1:+ 121

Ta)i 556 1 :+ <+; 11+0 1+0: 120 1;0 21:* 2+*+ *+1: ??2

7ar)i 526 1* 20< 2:1 *+ +; 2 :1 ;+* 1000 12 11.

Fro/ the abo-e results the following relationshi,s were obtaine) as shown in the figures below.

















The )eri-e) regional relationshi, between the catch/ent area an) the floo) /agnitu)e for eachreturn ,erio) )escribe) b regression e>uations are gi-en below along with their corres,on)ingcoefficient of correlation " 2.

2 6r Floo) 6 V *.0:<1W M0.;* " 2 V 0.<:*

10 6r Floo) 6 V ;.22:W M0.:2< " 2 V 0.<;2

20 6r Floo) 6 V 11.:+*W M0.:*+ " 2 V 0.<;11

100 6r Floo) 6 V 2+.*<;W M0.:+ " 2 V 0.<:+1

200 6r Floo) 6 V *2.<*:W M0.+;2 " 2 V 0.<<

00 6r Floo) 6 V +.<21W M0.1;* " 2 V 0.<1;

8here 6 V Floo) flow in /*?s an) M V )rainage area below *000 / in (/2.

The " 2 for all the abo-e relationshi,s are /ore than 0.< which show a -er goo) fit between the)ata ,oints an) hence the regression e>uations can gi-e reliable results.

The abo-e regression e>uations were use) to esti/ate the floo) flows at the inta(e site an) ,owerhouse site of $,,er "ahughat 4)roelectric Project. The catch/ent area below l.*000 /at the 'agar =hola inta(e site of $,,er "ahughat 4)roelectric Project is esti/ate) to be 2;

(/2

an) 202 (/2

at the ,owerhouse site.

shows the )eri-e) floo) flows at the inta(e site an) ,owerhouse site of $,,er "ahughat4)roelectric Project.

Tale 511 )stimated Floods 7or "pper Rahu#hat $ydroele%tri% Pro&e%t <m;s=

Return Period Ars Flood at :nta/e site Flood at Powerhouse2 +;.< 2210 10+. +:220 1*.; ;0

100 2*0.< ;:200 2;. 102;00 *;.* 120

5+5+ 8ry !eason 8i*ersion Flood

For the ri-er )i-ersion )uring the )r season it will be crucial to co/e to a co//on

un)erstan)ing as to the co//ence/ent of this season. For the $,,er "ahughat 4)roelectricProject the ,erio) fro/ !o-e/ber to 7a has been en-isage) as the )r season ,erio) for ri-er )i-ersion.





nfor/ation on recor)e) instantaneous floo) ,ea(s )uring the )r season is not a-ailable at thissite. Therefore to esti/ate the )r season floo) ,ea(s at the ,ro,ose) inta(e site a regional

a,,roach has been consi)ere) using the a)o,te) )r season )i-ersion floo)s at the h)ro,ower ,rojects in the -icinit of "ahughat =hola basin.

The following infor/ation in Table +%12 was use) to construct the regional relationshi,.

Tale 512 8ry !eason Floods at Various Pro&e%ts

Pro&e%t Name Cat%hment 'rea

/m2

1310 yr 8i*ersion

$,,er 7o)i A 4P B+2 78 **0 *0 /*?s=aruwa 4P B*0 78 2*+ 20 /*?s"ahughat 4P B2: 78 *0 2: /*?s

7o)i =hola 4P B1+ 78 10 +: /*?s

The following relationshi, was obtaine) as shown in the figure below.





4ence for an catch/ent area of + (/2 the 1 10 ear )r season floo) is esti/ate) as +.0 / *?s base) on the abo-e )eri-e) regional relationshi, which is reco//en)e) as the )i-ersion floo)for 'agar =hola inta(e site )uring the )r season.

5+5+5 )stalishment o7 >au#in# !tation and 8is%har#e Measurement

A gauging station was establishe) to /easure the flows in "ahughat. The gauging station islocate) just u,strea/ of the confluence of "ahughat =hola an) 'agar =hola. Dail/easure/ents are being ta(en fro/ this gauge. n a))ition to staff gauge /easure/ents flow/easure/ents ha-e also been carrie) out at this location an) at 'agar =hola. The /easure/entas ta(en on A,ril +th 2012 in)icates that the flow in "ahughat =hola is .;1 / *?s an) that in'agar =hola is 0.:0: /*?s. The gauge is being /aintaine) an) rea) b a local hel,er b thena/e of Dhurba =u/ar Paija. The )ischarge /easure/ent )ata an) the staff gauge recor)s are

,resente) in the Annex.




Upper Rahughat Hydroelectric ProjectSedi$entation Studies

?+0 !)8:M)NT:ON !T"8:)!

?+1 >eneral

The se)i/ent concentration an) the ,article si9e )istribution are re>uire) to )esign the)esan)ing basin. The cost of the )esan)ing basin is base) on the se)i/ent%la)en flow which hasto be flushe) out at the ti/e of ,ower ,lant o,eration. #therwise se)i/ent hea-il )a/ages theturbine bla)es scroll casing an) other /echanical ,arts.

t is -er )ifficult to esti/ate the se)i/ent concentration in a ri-er without an /easure/ents.f se)i/ent )ata is not a-ailable in the ri-er 4i/alaa Se)i/ent 6iel) Techni>ue is use) toesti/ate the se)i/ent iel).

?+2 $imalayan !ediment Aield Te%hniGues

'ase) on se)i/ent )ata for stations in !e,al n)ia an) Pa(istan 5.3. &ala Bsti/atingSe)i/ent 6iel) in 4i/alaan "i-ers ,ointe) out that the current se)i/ent ,ro)uction is lin(e)to )istinct geological 9ones. The @one S,ecific Se)i/ent 6iel) B@SS6 has )i-i)e) the se)i/entiel) areas into fi-e regions. Accor)ing to this theor the fi-e regions are as follows

Re#ions Ran#e o7 yield <t;/m2;year=

Tibetan Plateau 00%10004igh 4i/alaan *00%10004igh 7ountain 1000%+0007i))le 7ountain *000%;000Siwali( 000%1000

De,en)ing u,on the con)ition of the watershe) the iel) fro/ these areas is either low or high.For "ahughat =hola basin where the catch/ent area lies at 4igh 7ountain an) 7i))le7ountain areas the iel) esti/ate is carrie) out in the following wa.

Re#ions '*era#e Aields <t;/m2;year= Cat%hment area </m2=

4igh 7ountain 2000 *12 X +

The 4i/alaan se)i/ent iel) techni>ues use the ,ro,erties of Phsiogra,h of the ri-er basin.This /etho) ten)s to esti/ate the se)i/ent in conser-ati-e si)e Bhigher iel).

As $,,er "ahughat =hola 4)roelectric Project is a -er s/all ,roject in nature it is en-isage)that local factors coul) be /ore )ecisi-e in assessing the se)i/ent con)itions in the $,,er


Chapter Fi*e

!)8:M)NT'T:ON !T"8:)!



Upper Rahughat Hydroelectric ProjectSedi$entation Studies

"ahughat =hola. t is reco//en)e) that a /ore in )e,th stu) of the u,,er catch/ent areas bestu)ie) along the analsis of se)i/ent sa/,les collecte) at the fiel).

For the ,resent stu) the )esan)er has been base) on the re/o-al of a se)i/ent ,article si9e of 0.1 //. The fre>uenc of the flushing of the )esan)er has been base) on a se)i/ent iel) of 2000 t ? (/2 ?ear. The )esign of the )esan)er is )iscusse) in /ore )etail in Cha,ter < of thisre,ort.

?+ !ediment 8ata Otain 7rom Rahu#hat Pro&e%t

Se)i/ent )ata of 20+ an) 20 collecte) at &alehshor in the "ahughat ri-er has been obtaine)fro/ the "ahughat ,roject. These )ata are shown in the Annex of this re,ort. &rain si9e)istribution cur-e is shown in Figure .1. The se)i/ent /easure/ent an) sa/,ling ,rogra/ will

be continue) )uring this rainn season as well.

Fi#ure ?? >rain !ie 8istriution Cur*e

0 0.01 0.1 1 10 100 10000

10

20

*0

+0

0

0

:0

;0

<0

100

Dia/eter in //




Upper Rahughat Hydroelectric Project%eological Studies

.+0 >)OO>:C' 'N8 >)OT)C$N:C' !T"8:)!

.+1 :ntrodu%tion

$,,er "ahughat 4)roelectric Project is a run%off%ri-er h)ro,ower ,roject locate) in 7ag)iDistrict of Dhaulagiri @one in 8estern De-elo,/ent "egion !e,al. The ,roject area is locate)a,,roxi/atel one )as wal(ing )istance fro/ the roa) hea) at &aleshwor 'a9aar. &aleshwor islocate) on the right ban( of the confluence of =ali &an)a(i an) "ahughat =hola a,,roxi/atel* (/ north of 'eni 'a9aar which is )istrict hea)>uarters of 7ag)i )istrict. The recentlco/,lete) 'eni E 3o/so/ highwa ,asses through &aleshwor 'a9aar. The fiel) wor( for the geological an) geotechnical in-estigation of the ,roject has been carrie)out in the /onth of 3ul % August 200< an) geological an) all the necessar geotechnicalinfor/ation was collecte) fro/ this fiel) -isit. The /ain h)raulic structures of the ,roject are the hea)wor(s interconnection structure with"ahughat 7angale 4P a weir across 'agar =hola to ta, its water a surface )esan)ing basin

on the left ban( of 'agar =hola for the a))itional )ischarge fro/ 'agar =hola a hea)racetunnel surge shaft ,enstoc( ,i,e an) a surface ,owerhouse. xce,t for the )i-ersion weir thathas been ,ro,ose) across 'agar =hola all other structures are locate) on the left ban( of 'agar =hola. The ,roject area exten)s between a,,roxi/ate altitu)es of 100 / an) 2000 /.

.+2 O&e%ti*es

The /ain objecti-e of the geological an) geotechnical in-estigation was to carr out

- A regional geological as well as seis/icit stu) of the ,roject areaY

- Assess/ent of general geological con)ition of the ,roject areaY- &eological /a,,ing an) ,re,aration of /a,s of the ,roject area an) i/,ortant structurelocations in )ifferent scales 1 1000 an) 12000 as re>uire) for the )esign wor(s.

- "eco//en)ation of geotechnical ,ara/eters of soil an) roc( for slo,e stabilit an)foun)ation.

- Discontinuit sur-e slo,e stabilit analsis an) ,resentation of the result in gra,hicalfor/at.

- "oc( /ass classification an) su,,ort )esign for un)ergroun) structures. Analsis of thereco//en)e) su,,ort sste/ base) on fiel) obser-ations an) results.

- Assess/ent of a-ailabilit of construction /aterial )e,osit an) /uc( )is,osal sites in the ,roject area. The results obtaine) fro/ the geological an) geotechnical in-estigation

wor( shall be a ,art of the feasibilit le-el stu) of the ,roject.- "eco//en)ation for further in-estigation.


Chapter !i(

>)OO>:C' 'N8 >)OT)C$N:C' !T"8:)!




.+ iterature Re*iew

!o ,roject s,ecific geological an) geotechnical stu) has et been carrie) out for this ,roject inthe ,ast. #nl a few literature relate) to the geolog of the ,roject area is a-ailable. Thea-ailable literature an) other infor/ation were re-iewe) an) useful infor/ation was extracte)an) incor,orate) in the re,ort. So/e of the /aterials referre) to for the stu) are as follows

- To,ogra,hical /a, of the ,roject area BSheet !o. 2;;* 11A I 2;;* 0: in scale 1 0000 ,re,are) b Sur-e De,art/ent &o-ern/ent of !e,al.

- To,ogra,hical /a, in )igital for/at of the ,roject area at scale 1 10000

- Sur-e /a,Y scale 11000 ,re,are) )uring feasibilit stu).- Arial ,hotogra,h B'?8 ,airY scale 1 100000 of the ,roject area.- #ther rele-ant re,orts? )ocu/ents useful for the ,re,aration of the re,ort.-

.+5 Methodolo#y

The /etho)olog a)o,te) for the geological an) geotechnical stu) of the ,roject is )escribe) briefl in the following sections.

.+5+1 >eolo#i%al study

&eological /a,s of the ,roject area an) sites for the /ain structure ha-e been ,re,are) b/a,,ing the surface outcro,s using a geological co/,ass a geological ha//er an alti/eter a/easuring ta,e an) other necessar e>ui,/ents with the ai) of geo/or,hologic featuresa-ailable in the site. Di, )irection an) )i, a/ount of the structural features of the roc(s outcro,ssuch as be))ing foliation joint fault an) shear 9ones were note). The geological contact

between )ifferent roc( an) soil units were also trace) on the a-ailable to,ogra,hical /a,.

The /uc( )is,osal sites an) borrow areas for construction /aterial ha-e been reco//en)e) onthe basis of geological nature of a-ailable groun) haulage )istance fro/ the /ain consu/,tion

,oint ? tunnel outlet an) a-ailable -olu/e.

.+5+2 >eote%hni%al study

.+5+2+1 Ro%/ mass and soil %lassi7i%ation

"oc( /ass an) soil classification of the ,roject area has been ,erfor/e) to generali9e the roc( an) soil /aterial into )ifferent classes using internationall acce,te) /etho)s such as $nifie)Soil Classification B$SC sste/ for soil an) 'artons roc( >ualit in)ex QQ sste/ for roc( /ass. Also intact roc( an) roc( /ass ,ara/eters such as &eo/echanical Strength n)ex B&S

an) roc( /ass constants ha-e also been esti/ate) as ,ro,ose) b -arious authors for roc( /echanical analsis.





.+5+2+2 Ro%/ support desi#n

"oc( /ass su,,orts for un)ergroun) exca-ations ha-e been reco//en)e) using the abo-ee/,irical /etho)s. Further analsis has been carrie) out b finite ele/ent analsis to chec( thereaction of the reco//en)e) su,,ort sste/ for the antici,ate) roc( /ass. Possibilit of thefor/ation of un)ergroun) we)ge for existing )iscontinuit sste/ an) tunnel si9e ? orientationhas been e-aluate).

.+5+2+ !lope staility analysis

7easure) )iscontinuities were ,lotte) on the lower he/is,here of the stereonet. #rientationB)i, an) )i, )irection of /ain )iscontinuit were obtaine) statisticall for the analsis of thesurface ? slo,e stabilit.

.+? Re#ional >eolo#y

Accor)ing to the geological )i-ision of !e,al the ,roject area lies in the Lesser 4i/alaan unitwhich is occu,ie) b low gra)e /eta/or,hic roc(s such as slate ,hllite >uart9ite etc. Thelocation of ,roject area has been shown in the regional /a,.

Fi#ure .. o%ation o7 pro&e%t area in re#ional #eolo#i%al map

!e,al has been broa)l )i-i)e) into fi-e lithologic units fro/ north to south the are % TibetanTeths unit 4igher 4i/alaan unit Lesser 4i/alaan unit Siwali( unit an) Terai ,lain. TheTibetan Teths $nit is ex,ose) onl occasionall within the territor of !e,al while the other


"pper Rahu#hat $)P




four units are )istribute) fro/ east to west throughout the countr. The Tibetan%Teths @one begins at the to, of the 4igher 4i/alaan @one an) exten)s to the north in Tibet. This 9one isco/,ose) of se)i/entar roc(s such as shale li/estone an) san)stone ranging in age fro/

Lower Paleo9oic to Paleogene.

The 4igher 4i/alaan $nit inclu)es the roc(s ling north of the 7CT an) below thefossiliferous Tibetan%Teths @one. This 9one consists of an a,,roxi/atel 10 (/ thic( succession of crstalline roc(s also (nown as the Tibetan Slab. The crstalline unit of the higher 4i/alaa exten)s continuousl along the entire length of the countr an) its wi)th -aries fro/

,lace to ,lace. The high%gra)e (anite%silli/anite bearing gneisses schists an) /arbles of the9one for/ the base/ent of the Tibetan Teths 9one. &ranites are foun) in the u,,er ,art of theunit. The Lesser 4i/alaan @one is bor)ere) in the south b the 7'T an) in the north b the 7ain

Central Thrust B7CT. The Lesser 4i/alaan roc(s throughout the 4i/alaas consist of twose>uences allochthonus an) autochthonus. The 7'T itself is a fault 9one that has brought ol)er Lesser 4i/alaan roc(s o-er the Siwali(. The Lesser 4i/alaas are /ostl co/,rise) of unfossiliferous se)i/entar an) /eta%se)i/entar roc(s such as slate ,hllite schist >uart9iteli/estone )olo/ite etc. ranging in age fro/ Preca/brian to ocene. There are also so/egranitic intrusions in this 9one.

$,,er "ahughat 4)roelectric ,roject area lies in the Lesser 4i/alaan $nit of 8estern !e,al.Phllite an) >uart9ite are the /ain roc( t,es ,resent in the ,roject area. Detaile) geological)escri,tions of the s,ecific structural locations of the )ifferent ,roject co/,onents ha-e been

,resente) in Section .: of this cha,ter. The Siwali( is boun)e) in the north b the 7ain 'oun)ar Thrust B7'T an) in the south bthe 7ain Frontal Thrust B7FT. t consists basicall of flu-ial )e,osits of the !eogene age. TheLower Siwali( consists of finel la/inate) san)stone siltstone an) /u)stone. The /i))leSiwali( are co/,rise) of /e)iu/ to coarse graine) salt an) ,e,,er t,e san)stones. The $,,er Siwali( is co/,rise) of conglo/erates an) boul)er be)s. The )un -alles within the Siwali( consist of uatenar flu-ial se)i/ents. The Terai @one re,resents the northern e)ge of the n)o%&angetic allu-ial ,lain an) is thesouthern/ost tectonic )i-ision of !e,al. Though ,hsiogra,hicall this 9one )oes not belong to

the /ain ,art of the 4i/alaas it is a forelan) basin an) owes its origin to the rise of the4i/alaas it is thus geneticall relate). To the north this 9one is often )elineate) b an acti-efault the 7ain Frontal Thrust B7FT. The Siwali( roc(s are foun) to rest o-er the se)i/ents of the Terai in /an ,laces along this thrust. The Terai is co-ere) b Pleistocene to recentallu-iu/. The a-erage thic(ness of the allu-iu/ is about 100/. The base/ent to,ogra,h of the Terai is not unifor/. The Terai region contributes significant >uantit of goo) >ualitconstruction /aterial an) groun)water in !e,al.

.+. !eismi%ity

The 4i/alaa seis/icit in general owes its origin to the continue) northwar) /o-e/ent of

n)ian ,late after continental collision between n)iana ,late an) urasian ,late. The /agnitu)erecurrence an) the /echanis/ of continental collision )e,en) u,on the geo/etr an) ,late-elocit of n)ian ,late in relation to southern Tibet Burasian Plate. "ecent results suggest thatthe con-ergence rate is 20// ,er ear an) the n)ian ,late is sub%hori9ontal below the Sub%





4i/alaa an) the Lesser 4i/alaa. !e,al 4i/alaa occu,ies the central one%thir) ,ortion of 4i/alaan arc. nterseis/ic /onitoring of )efor/ation in)icates that the 7ain 4i/alaanThrust B74T is loc(e) along the 4i/alaa of !e,al an) that stress buil) u, at the ti, of the

loc(e) 9one is res,onsible for the belt of /icroseis/icit acti-it that runs along the front of the

high range BPan)e et. al. 1<<<Y Cattin an) A-ouac 2000. The interface between the n)ian base/ents along a sub hori9ontal )ecolle/ent is (nown as 7ain 4i/alaa Thrust. 7otionalong the 74T is thus ,robabl stic(%sli, an) /ust ,ro)uce recurring large earth>ua(es si/ilar to the 1<*+ 'ihar%!e,al e-ent. The /o)erate /agnitu)e earth>ua(e is generate) fro/ thrustfaults which originate within the /icroseis/ic belt in the front of high 4i/alaan in the ra/,an) ra/, flat transition -icinit. The result of /icro seis/ic in-estigation geo)etic /onitoringan) /or,hotectonic stu) of the Central !e,al has )e,icte) that /ore fre>uent /e)iu/ si9e)earth>ua(e of to : /agnitu)e are confine) either to flat )ecolle/ent beneath the lesser

4i/alaa or the u,,er ,art of the /i))le crustal ra/,. The ra/, is occurring at about 1 (/)e,th below the foothills of the 4igher 4i/alaa in the south of 7CT surface ex,osure. 'ige-ents of /agnitu)e greater than eight are nucleate) near the ra/, flat transition an) ru,ture thewhole ra/,%flat sste/ u, to the 7'T of the Sub%4i/alaa BPan)e et. al. 1<<. Anearth>ua(e is characteri9e) b a uni>ue /agnitu)e but it can gi-e rise to a range of intensit.The highest intensit is generall obser-e) in the e,icenter area. t )ecreases ra,i)l beon) theru,ture area as we /o-e awa fro/ the e,icenter.

Fi#ure .4 !eismi%ity map o7 Nepal

Project s,ecific seis/ic stu)ies ha-e not been carrie) out for the ,roject. The recor)s of seis/ic

acti-ities are li/ite) in !e,al 4i/alaas an) hence correlation of seis/ic e-ents with a)jacent4i/alaan "egion woul) be a useful source of infor/ation for )esigning such h)raulicstructures. Se-eral seis/icit stu)ies ha-e been carrie) out b Seis/icit De,art/entDe,art/ent of 7ines an) &eolog BD7& !e,al. The D7& has ,ro)uce) a -er useful /a,


P"#3C




QSeis/icit 7a, of !e,alQ showing the le-el of seis/icit contours within the countr. The /a,re-eals that the ,roject area is locate) at a contour with hori9ontal seis/icit coefficient of 20gal e>ui-alent to 0.2 g.Consi)ering the ratio of hori9ontal to -ertical seis/ic coefficient to be

1. the -ertical seis/ic coefficient will be 0.1:. Since an earth>ua(e can oscillate in an)irection the worst case scenario shoul) be consi)ere). 4ence the reco//en)e) seis/iccoefficient for this ,roject is 0.2.

.+4 >eolo#y o7 the Pro&e%t 'rea

.+4+1 >eneral >eolo#y

The ,roject area is locate) in Lesser 4i/alaan unit in /i)%western !e,al. The /ain roc( t,esfoun) in the ,roject area are ,hllite an) >uart9ite belonging to =unchha For/ation an) Fagfoguart9ite res,ecti-el /entione) b Stoc(lin an) 'hattarai elsewhere in the literatures ongeolog of !e,al 4i/alaas. Towar)s the )ownstrea/ area near 'u(ula 5illage highl Bcube

jointe) E crushe) /o)eratel to highl weathere) )ar(%blac( slate is ,resent an) can be seenalong roa) cuts. Fre>uent lan)sli)es are foun) to occur in this area an) it is attribute) to ,oor roc( /ass >ualit. Lan)sli)es are usuall foun) to occur in areas with a relati-el stee, naturalslo,e.

Co/,arati-el wea( ,hllite roc( is un)erlain b -er co/,etent >uart9ite roc( thus ,ro)ucingse-eral s/all an) large scale )efor/ations Bfol)ing in the roc( /ass. The >uart9ite is onlslightl weathere) green E white an) strong E -er strong. Two E three sets of joints inclu)ingfoliation ,lane are ,resent in the >uart9ite. n ,laces natural slo,e is controlle) b secon)ar

joints. Con-ersel ,hllite is /o)eratel to highl weathere) gre E greenish blue colore) softto /e)iu/ strong. t is ,re)o/inantl thinl to /e)iu/ foliate).

n general the be)roc( )i,s towar)s the u,strea/ )irection an) the /ain un)ergroun) structureof the ,roject which is the hea)race tunnel will ha-e a fa-orable orientation with res,ect to the/ain )iscontinuit orientation. The hea)race tunnel will be exca-ate) al/ost ,er,en)icular tothe stri(e of the foliation ,lane BDrawings. $"%&%PA1.

Slo,e stabilit of the ,roject area is such that the left ban( of "ahughat =hola is relati-elstable co/,are) to the right ban(. Large scale) lan)sli)es B200 /2 are ,resent along the right

ban( o,,osite to the location of Chi/(hola 5illage. A /o)erate lan)sli)e was also obser-e)

further )ownstrea/ of the ,ro,ose) ,owerhouse site. Few s/aller lan)sli)es were seen to existalong the cree(s aroun) Dagna/ an) Asi/a -illage area which is the area of the location of the ,owerhouse. "elati-el big lan)sli)es are attribute) to an unfa-orable relation between the be)roc( foliation an) the natural slo,e of the groun). n a lan)sli)e area the angle of the )i,,ing be) roc( is also the )i,,ing angle of the /ain )iscontinuit set Bthe foliation ,lane. 8hen thisstructure is not abutte) to the botto/ of the -alle sli)ing is aggra-ate) )ue to the scouring of the toe of the slo,e. !ext to the foliation the other /ajor )iscontinuit set runs al/ost ,arallel tothe -alle slo,e thus cutting the roc( /ass into bloc(s easing the sli)ing ,rocess towar)s the)ownhill slo,e. n case of the left ban( the situation is al/ost o,,osite. The be) roc( )i,s intothe hillsi)e creating a relati-el stable situation. This has been e-i)ence) b the ,resence of -erfew slo,e instabilit features along the left ban(.

The geological features of the sites for the location of the )ifferent structures ha-e beenelaborate) in the following sections. /,hasis has been gi-en to the geotechnical ,ro,erties of





the roc( /ass existing con)itions of the groun) /aterial relate) to the foun)ation of thestructures stabilit of the slo,es an) con)itions regar)ing the un)ergroun) exca-ation wor(s.

.+4+2 $eadwor/s 'rea

The ,ro,ose) hea)wor(s structure for $,,er "ahughat 4)roelectric Project basicall consistsof structures interconnecting the tailrace of "ahughat 7angale 4)ro,ower Project B"74P a

ri-er )i-ersion structure for 'agar =hola an) the inta(e for $,,er "ahughat 4)roelectricProject B$"4P. The tailwater fro/ "74P is ,ro,ose) to be brought across 'agar =hola toits left ban( si)e with the ,ro-ision of an in-erte) si,hon. The )ischarge fro/ 'agar =hola willalso be )i-erte) with the ,ro-ision of a s/all weir across the (hola an) will use) for ,ower generation before being ta(en into a collection cha/ber locate) just before the inta(e ,ortal for the hea)race tunnel of $"4P. The in-erte) si,hon carring the )ischarge fro/ the tailwater of "74P will also be connecte) to this collection cha/ber so that the flows fro/ both "74Pan) 'agar =hola tailrace can collecti-el be release) into the inta(e ,ortal of the hea)racetunnel for $"4P. xce,t for the in-erte) si,hon an) the weir across 'agar =hola all of thesestructures will be locate) on the left ban( of 'agar =hola an) will be foun)e) on the allu-ial)e,osit ,resent in the area.

The allu-ial )e,osit is /a)e u, of strong big boul)ers of gneiss >uart9ite an) schist etc.inclu)ing silt an) can thus be )escribe) as coarse graine) boul)er /ixe) soil E silt gra-el. The/axi/u/ si9e of the boul)er is /easure) to be about / BDrawing $"%&%48%01.

The inta(e weir across 'agar =hola as well as the ,owerhouse will howe-er be exca-ate) an)foun)e) ,artl on allu-ial an) ,artl on collu-ial )e,osit. The thic(ness of the collu-ial )e,osithas been esti/ate) to be about : /. The cut slo,e gra)ient on left ban( of the )esan)ing basin isreco//en)e) to be 1 B41.; B5 to 1 2.0.





Photo 5+13 Proposed headwor/s inter%onne%tion area around a#ar Khola, loo/in#

7rom ri#ht an/

.+4+ $eadra%e Tunnel

The a,,roxi/atel +;:2 / long hea)race tunnel is ,ro,ose) to be locate) along the left ban( of "ahughat =hola. 7ainl two t,es of roc( /ass are ,resent along the align/ent of the hea)racetunnel the are ,hllite an) >uart9ite. Phllite occu,ies a,,roxi/atel : O of the total lengthof the tunnel. The rest of the tunnel length is occu,ie) b >uart9ite. uart9ite occu,iesa,,roxi/atel 1*00 / of the length of the tunnel between A)it !o. 1 an) A)it !o. 2. 8hiteslightl weathere) fresh strong to -er strong /e)iu/ foliate) >uart9ite roc( is ,resent alongthe length of the tunnel aroun) A9ingar 5ir area. This roc( t,e is ,rojecte) at the section

between A)it !o. 1 an) A)it !o. 2. The for/ation of the stee, cliff aroun) A9ingar 5ir near

Dagna/ 5illage is )ue to the strong resisti-e >ualities of the >uart9ite roc( against weatheringan) erosion. n other ,laces aroun) Dar/ija 5illage the greenish >uart9ite is ,resent in the for/of interbe))ing with ,hllite. The ,hllite is gre colore) slightl to /o)eratel weathere) thinto /e)iu/ foliate) slightl to /o)eratel weathere) soft to /e)iu/ strong. Sncline an)anticline structures are ,resent in A9ingar 5ir area where wea( ,hllite roc( is ,resent alongwith strong >uart9ite roc(. The fol)ing in roc( /ass is attribute) to )ifferent )egrees of )efor/abilit un)er the sa/e loa)ing ? en-iron/ental con)ition for )ifferent roc( t,es.


'>'R K$O'




Photo 5+23 Conta%t etween thinly 7oliated phyllite and medium to thi%/ly 7oliated

Guartite as seen on the way throu#h 'in#ar Vir+ Conta%t is mar/ed withdotted line+

Discontinuit /easure/ents were carrie) out to (now the orientation of the /ain )iscontinuitsets in the ,roject area. The ,resence an) orientation of ,ersistent )iscontinuit sets ,la a -italrole in the tunnel stabilit thus influencing the ,rogress of the wor(. The ,ro,ose) )irection of

the exca-ation of the tunnel along with the )iscontinuit sets ha-e been ,lotte) in the sa/estereonet to gra,hicall -isuali9e their relationshi,. n general the be)roc( )i,s u,strea/ at anangle of about 20 )egrees.


P46LLT

$A"T@T



!

S

8

4"T BT0%T1

!u/ber of Poles

1 ,ole

>ual Angle

Lower 4e/is,here

; Poles

; ntries


Fi#ure .6 !tereo#raphi% Pro&e%tion o7 8is%ontinuities <:nta/e Portal 'rea=

Stereogra,hic ,rojection of )iscontinuities /easure) in the hea)race tunnel align/ent aroun)the inta(e ,ortal area. The hea)race tunnel )ri-e )irection for the first stretch BT0 to T1 has been shown in the figure. Concentration of ,lanes )i,,ing )ue ! re,resents the /ain)iscontinuit set E foliation ,lane.

The abo-e ,lot shows that the tunnel align/ent is obli>ue to the /ain )iscontinuit set which isa fair con)ition for tunneling.

The hea)race tunnel exca-ation )irection an) )iscontinuit orientation has also been ,lotte) for the hea)race tunnel in the area aroun) A)it !o. 1.




!

S

8

4"T a)it 1 area

Poles

>ual AngleLower 4e/is,here

20 Poles20 ntries


Fi#ure .- !tereo#raphi% Pro&e%tion o7 dis%ontinuities <'dit No+ 1 'rea=

Stereogra,hic ,rojection of )iscontinuities along the hea)race tunnel align/ent aroun) A)it !o.1 area. The hea)race tunnel )ri-e )irection has also been shown in the figure. Concentration of

,lanes )i,,ing )ue !8 re,resents /ain )iscontinuit set E foliation ,lane.

The abo-e ,lot shows that the tunnel align/ent is obli>ue to the /ain )iscontinuit set %foliation ,lane which is a fair con)ition for tunnel exca-ation. Co/,are) to the foliation other )iscontinuities are -er few in the /easure) area.




!

S

8

4"T Bu?s surge shaft

""T B)?s surgeshaft

Poles

>ual Angle

Lower 4e/is,here

Poles

ntries


Fi#ure .10 !tereo#raphi% Pro&e%tion o7 8is%ontinuities <!ur#e Tan/ 'rea=

Stereogra,hic Projection of )iscontinuities /easure) along the hea)race tunnel align/ent in thesurge shaft area. Straight line insi)e the circle re,resents hea)race tunnel )ri-e )irection. PlanesH)i,,ing )ue ! an) !8 re,resents /ain )iscontinuit set E foliation ,lane which is fol)e).

.+4++1 Ro%/ Mass Classi7i%ation

"oc( /ass classification of the areas ,ro,ose) for the location of the )ifferent structureses,eciall along the hea)race tunnel has been /a)e accor)ing to internationall acce,te)/etho) the (nown as the QQ sste/ )e-elo,e) at the !orwegian &eotechnical nstitute B!&in 1<:+ an) later u,)ate) in 1<<*. t is a >uantitati-e classification sste/ for the esti/ate of the

tunnel su,,ort base) on a nu/erical assess/ent of the roc( /ass >ualit using the followingrelationshi, of six ,ara/eters

8here V roc( /ass >ualit in)ex"D V roc( >ualit )esignation3n V joint set nu/ber 3r V joint roughness nu/ber

3a V joint alteration nu/ber 3w V joint water re)uction factor S"F V stress re)uction factor





n fiel) the "D has been esti/ate) using the following relation"D V B11 E *.*W3- O

8here 3- is the total nu/ber of )iscontinuities ,er /* BV su/ of nu/ber of )iscontinuities ,er /eter length of all )iscontinuit sets.

Tale .1 Ro%/ mass %lassi7i%ation alon# headra%e tunnel ali#nment

From To len#th, m E Value Ro%/ mass %lass

0 200 200 0.0+ E 1.21 5er ,oor E ,oor

200 12: 10: 0.1 E *.* Poor E fair

12: 2000 :2 0.0 E :.0+ 5er ,oor E fair

2000 **00 1*00 *.: E 2:.;: Fair E goo)

**00 +2;0 <;0 2.; E 1*.2 Fair E goo)

+2;0 +0 +0 0.2; E 1.: Poor E fair

+0 +;00 1< 0.0: E 2.2 5er ,oor E ,oor !ote "1 stan)s for -er goo) roc( "2 stan)s for goo) roc( "* stan)s for fair roc( "+ stan)s for ,oor roc( an) " stan)s

for -er ,oor roc(. Si/ilarl roc( su,,ort t,es S1 to S ha-e been reco//en)e) for corres,on)ing roc( /ass classes"1 to ".

Tale .15 8istriution o7 ro%/;support type alon# headra%e tunnel

7rom to len#th, mRo%/; support type D

"1?S1 "2?S2 "*?S* "+?S+ "?S

0 200 200 0 0 *0 0 10

200 12: 10: 1 * *0 1

12: 2000 :2 0 1 +0 *0 1

2000 **00 1*00 *0 0 1 0

**00 +2;0 <;0 0 20 2 +0 1+2;0 +0 +0 0 *0 + 20

+0 +;00 1< 0 0 20 +0 +0

Tale .1? !ummary o7 support len#th 7or headra%e tunnel

Ro%/ Class ; !upport Type

"1?S1 "2?S2 "*?S* "+?S+ "?S Total

en#th,m *1* 11*2 1*02 1+0 + +;00

en#th, D . 2*. 2:.1 2<.* 1*. 100





.+4++2 Ro%/ Mass !upport

The roc( su,,orts ha-e been esti/ate) on the basis of the abo-e classification of the roc( /ass.For )i/ension of roc( su,,ort sste/ such as roc( bolt length s,acing of roc( bolt an)thic(ness of shotcrete a built%in%chart suggeste) b 'arton has been use).

Fi#ure .11 )stimated support %ate#ories ased on E *alues

<a7ter >rimstad and arton 1--=

The tunnel su,,orts ha-e been reco//en)e) on the basis of the -alue an) e>ui-alent

)i/ension BDe. The -alue De is )efine) b the ratio of the exca-ation s,an either the)ia/eter or the height B/ of the tunnel to the xca-ation Su,,ort "atio BS". 4ere for thehea)race tunnel the tunnel s,an is +.0 / an) the S" has been ta(en as 1.0 gi-ing the -alue of De to be +.0.

"oc( bolts ha-e been the /ost effecti-e su,,ort sste/ in a tunnel whose length )e,en)s on thetunnel s,an ra)ius of ,lastic 9one aroun) the tunnel ,eri/eter an) the -alue of S" in)icate)abo-e. The bolt length L for hea)race tunnel Bs,an +.0 has been co/,ute) as

L V B2 X 0.1W'?S"

Thus L V 2./

Altogether fi-e )ifferent categories of su,,orts ha-e been reco//en)e) for the hea)race tunnel)e,en)ing on the roc( /ass classes. Details of the su,,ort classes for each categor S1 S2 S*


De for 4"T V +




S+ an) S ha-e been shown in the )rawings. The actual )istribution of the )ifferent t,e of roc(

/ass an) su,,ort t,es along the hea)race tunnel an) the construction a)it can howe-er be)eci)e) onl after the actual exca-ation of the tunnel )uring the construction of the ,roject.Tentati-e locations of the roc( /ass class an) their corres,on)ing su,,ort t,es are elaborate)in the following text as well as in )rawings. The roc( su,,ort wor( is nor/all carrie) out in two stagesY the initial su,,ort stage an) the ,er/anent su,,ort stage. The initial su,,ort is installe) to secure safe wor(ing con)itions for thetunneling crews. The initial su,,ort is usuall )esigne) to constitute a ,art of the ,er/anent roc( su,,ort.

The ,er/anent su,,ort is installe) to /eet the re>uire/ent for satisfactor functioning of the

,roject )uring its life. The final su,,ort for )ifferent roc( /ass classes has been reco//en)e)to be as followingY

Tale .1. Ro%/ mass support 7or tunnel

Ro%/ mass %lass R1 R2 R R5 R?

Rock support class &1 &2 &3 &4 &5

Rock bolt

diam.

Length, m 2.5 2.5 2.5 2.5 -

Spacing, m

&pot 1.5'2 1.5'1 1.$'1 -

Shotcrete Thickness, A( !5 12$ 15$ -Steel rib

Spacing, m - - - - 1.$

"oncrete lining on roo# and

- - - - 2$$

In%ert concrete lining, mm 2$$ 2$$ 2$$ 2$$ 3$$

Pre%exca-ation su,,ort co/,rising of s,ile bolts or grouting or a co/bination of both )e,en)ingon the site con)ition /a be necessar in tunnel stretches occu,ie) b -er ,oor roc( /ass. Thes,ile bolt shoul) be +.0 / long with an o-erla, of 0 O of its length an) s,ace) at 0 c/ aroun)the tunnel contour.

.+4++ Ro%/ Mass !tren#th

The 4oe( 'rown classification sste/ has been use) to fin) out the roc( /ass ,ara/eters for the analsis of the strength of the roc(. n,ut ,ara/eters ha-e been esti/ate) on the basis of

built%in charts an) tables base) on roc( t,e an) geological con)itions in the stu) area.7ainl two t,es of roc( /ass are ,resent in the stu) area the are >uart9ite an) ,hllite.Thus the analsis has been carrie) out for both of these roc( t,es.

Euartite

For >uart9ite the in,ut ,ara/eters an) the resulting out,ut in the for/ of roc( /ass ,ara/etersha-e been tabulate) below. 7axi/u/ roc( co-er an) a resulting in%situ stress of +10 7,a will

be a-ailable at Chainage 2<00 / of hea)race tunnel.





Tale .14 :nput *alues ; parameters 7or %al%ulation o7 ro%/ mass stren#th parameters

Input parameters Input %alue Remarks

*nta+t uniaxia, +ompre((ive

1$$ E(timated in 0e,d

eo,ogi+a, (trengt index 55 E(timated u(ing ui,t-

o+ ma(( +on(tant mi 2$ E(timated

i(turan+e 6a+tor 78 $.5 E(timated

9nit weigt o6 ro+ ma(( 7g:+m38 $.$2 E(timated

App,i+ation Tunne,

ept to tunne, m 41$

*nta+t modu,u( 7Ei8 3!5$$

/odu,u( atio 7/8 3!5 E(timated

The results fro/ the abo-e calculation ha-e been tabulate) below.





Tale .16 Output ro%/ mass stren#th parameters

Criteria Parameters &alue

;oe <rown m 3.!!"

( $.$$#4

a $.5$2

/or-Cou,om %it Coe(ive (trengt = + /pa 2.4#1%ri+tion ang,e = > 7$8 5$.12

o+ /a(( 9niaxia, +ompre((ive (trengt 7?+m8 #.$"

Ten(i,e (trengt /pa

,oa, ro+ ma(( +ompre((ive

2.55

/odu,u( o6 de6ormation /pa 13221

Phyllite

For ,hllite the in,ut ,ara/eters an) the resulting out,ut in the for/ of roc( /ass ,ara/etersha-e been tabulate) below. 7axi/u/ roc( co-er of ++0 / has been use) for this co/,utationwhich is ,resent at Chainage 0 X *:00/.

Tale .1- :nput *alues ; parameters 7or %al%ulation o7 ro%/ mass stren#th parameters

Input parameters Input Remarks

*nta+t uniaxia, +ompre((ive

5$ E(timated in 0e,d

eo,ogi+a, (trengt index 45E(timated u(ing ui,t-in-

o+ ma(( +on(tant mi ! E(timated

i(turan+e 6a+tor 78 $.5 E(timated

9nit weigt o6 ro+ ma(( 7g:+m38 $.$2 E(timated

App,i+ation Tunne,

ept to tunne, m 44$

*nta+t modu,u( 7E8 /Pa 2!5$$

/odu,u( atio 7/8 55$ E(timated





The results fro/ the abo-e calculation ha-e been tabulate) below.

Tale .20 Output ro%/ mass stren#th parameters

Criteria Parameters &alue

;oe <rown

Criterion

m $.51$

( $.$$$!

a $.5$"

/or-Cou,om %it Coe(ive (trengt - + /Pa $.#12

%ri+tion ang,e - > 7$8 2!."29niaxia, +ompre((ive (trengt 7?+m8 1.2





Ten(i,e (trengt /Pa

,oa, ro+ ma(( +ompre((ive

4.

/odu,u( o6 de6ormation /Pa 2#12

'nalysis o7 Ro%/ !tresses

The roc( /ass aroun) the tunnel contour fails )ue to -arious reasons such as when the tangentialstresses a,,roaches or excee)s the ,re-ailing roc( /ass strength. Tunnel exca-ation results inthe re)istribution of stresses aroun) the tunnel. An e-aluation on the ,ossibilit of roc( /assfailure )ue to roc( stress ,roble/s has been /a)e using a co/,uter ,rogra/. Since no in%situroc( stress /easure/ent has been ,erfor/e) in this ,roject the /ajor ,rinci,le stress has beenassu/e) to be cause) b the roc( co-er abo-e the tunnel roof. The /axi/u/ roc( co-er alongthe hea)race tunnel is about ++0 / at a )istance of about *:00 / fro/ the inta(e ,ortal at asection where ,hllite roc( is ,resent. Consi)ering the unit weight 0.02 =g?c/ * for ,hlliteroc( the roc( co-er ,ro)uces a -ertical stress of 11. 7Pa. The corres,on)ing roc( /assstrength has been co/,ute) to be a,,roxi/atel +. 7Pa lesser than the -ertical stress. Thus it

can be ex,ecte) that the roc( /ass fails in the tunnel boun)ar when it is exca-ate). The failuresto,s further ,ro,agation when the roc( /ass strength excee)s the in)uce) stresses insi)e thetunnel wall.





Fi#ure .12 Tunnel de7ormation *ersus ro%/ mass stren#th to insitu stress

The ratio of the roc( /ass strength to the in%situ stress is 0.+0. For a tunnel )ia/eter of +.0 / theabo-e figure shows that the tunnel )efor/ation in ,ercent strain will be about 2 O i.e. there will

be a tunnel closure of about ; c/.

'nalysis o7 ro%/ mass eha*ior and support response usin# 7inite element analysis

$sing the abo-e roc( /ass ,ara/eters the in%situ stress con)ition an) the tunnel )i/ensions afinite ele/ent analsis has been carrie) out to assess the roc( /ass res,onse after the tunnelexca-ation of the tunnel an) after the installation of the su,,orts. The /aterial is consi)ere) to

be ,lastic in nature an) the stress is )ue to roc( co-er as well as h)rostatic ,ressure. ThePoissonHs ratio for the roc( /ass has been ta(en as 0.2.





Fi#ure .1 Finite element mesh #enerated 7or stress analysis





Fi#ure .15 Plot o7 Ma&or Prin%ipal !tress <I 1=

BAlong exca-ation boun)ar for assu/e) stress en-iron/ent

Fi#ure .1? Plot o7 !tren#th Fa%tor Contour

BShowing iel)e) ele/ents aroun) hea)race tunnel at /axi/u/ roc( co-er area





The abo-e ,lot shows that the roc( /ass aroun) the tunnel boun)ar iel)s a,,roxi/atel atunnel )ia/eter awa fro/ the tunnel wall )e/an)ing an a,,lication of a)e>uate su,,ort.

A))itional analsis was carrie) out for con)itions using a))itional roc( su,,ort. The a))itionalsu,,ort use) for the analsis consiste) of roc( bolts an) shotcrete. The )i/ension of the roc(

bolt an) the thic(ness of the shotcrete use) for this analsis are ,resente) below.

Rock bolt properties<o,t type@ %u,,y onded

Lengt@ 2.5 - 3.$ m

iameter@ 25 mm

&pa+ing 7+:+8@ 1.$ ' 1.5 m<o,t modu,u( 7E8@ 2$!$$$ /Pa

Ten(i,e +apa+ity@ $.2 /

e(idua, ten(i,e +apa+ity@ $.2 /

Fi#ure .1. "se o7 ro%/ support %onsistin# o7 ro%/ olt and liner <shot%rete=


Shotcrete properties

Boung( modu,u( 7E8@ 2$$$$

/Pa

Poi((on( ratio@ $.25

/ateria, type@ P,a(ti+

Compre((ive (trengt 7pea8@ 3$

/Pa

Compre((ive (trengt 7re(idua,8@ 5

/Pa




Fi#ure .14 !tren#th 7a%tor %ontour distriution around e(%a*ation oundary+

"oc( /aterials fail unifor/l aroun) tunnel contour

Fi#ure .16 Plot o7 per%enta#e o7 yielded elements a7ter usin# support+

!o bolts are iel)e). #nl four liner ele/ents are iel)e) at botto/? in-ert corner. The bolts areexten)e) beon) the iel)e) 9one.





Thus the reco//en)e) su,,ort >uantit shoul) be sufficient for the antici,ate) roc( /asscon)ition. The actual roc( /ass su,,ort can be )eci)e) onl at the ti/e of exca-ation of thetunnel )uring the construction of the ,roject.

.+4+5 Constru%tion 'dit

Two construction a)its ha-e been ,ro,ose) at )ifferent locations to )i-i)e the hea)race tunnelinto three ,arts thus easing its exca-ation an) su,,ort wor(. A)it !o1 has a length of 1; / an)is locate) 1+:: / )ownstrea/ of the inlet ,ortal. Si/ilarl A)it !o 2 with a length of 212 / islocate) 22;< / )ownstrea/ of A)it !o 1. The length of the hea)race tunnel )ownstrea/ of A)it

!o 2 is 10*+ /. Thus the hea)race tunnel ha-ing a total length of +;00 / has been )i-i)e) into

three stretches with a total of six wor(ing faces to ease the construction of the hea)race tunnel.

The construction a)its will onl be ,ro-i)e) with te/,orar initial su,,orts to ,ro-i)e safewor(ing con)ition )uring the construction ,erio).

!%alin#

Scaling is re>uire) after each blasting. For a tunnel of this si9e it will be )one /anuall using acrowbar. Perio)ic scaling Bonce a wee( will be re>uire) to re/o-e the stress relie-e) loose roc(

bloc(s. The scaling constitutes a ,art of su,,ort wor( in a tunnel.

.+4+? !ur#e sha7t

The surge shaft will be constructe) in the area of Asi/a an) Dagna/ -illage a,,roxi/atel 200/ u,strea/ of the tunnel outlet. The surge shaft will be exca-ate) in be)roc( consisting of

,hllite. The roc( /ass in the ,ro,ose) location of the surge shaft is gre E )ar( slightl E /o)eratel weathere) fine graine) soft E /e)iu/ strong ,hllite.

The su,,ort sste/ ,ro,ose) for the surge shaft also consists of a co/bination of roc( bolts an)shotcrete. The reco//en)e) roc( su,,ort for the surge shaft is as follows.

Ro%/ olt

Dia/eter 2//Length /S,acing 2/ W 2/

!hot%rete

Fibre reinforce) shorcrete thic(ness 10 E 200//

.+4+. Pensto%/ 'li#nment

A surface ,enstoc( has been ,ro,ose) fro/ the en) of the hea)race tunnel u,to the ,owerhouse.The surface ,enstoc( will be su,,orte) b a nu/ber of anchor bloc(s an) sa))le su,,orts. So/eof the sa))le su,,orts an) anchor bloc(s will be foun)e) on soil an) so/e will be foun)e) on





be)roc( Bsee geological ,rofile along ,enstoc( align/ent. The be) roc( ex,ose) in so/e ,lacesalong the ,ro,ose) ,enstoc( align/ent is bluish /o)eratel E highl weathere) fine graine)

wea( E strong ,hllite. The /ajor )iscontinuit set in the roc( /ass is the foliation ,lane with a)i, )irection of 2:0 0 an) a )i, a/ount of 1 0. A few lan)sli)es ha-ing s/all areas are ,resentalong the cree( in the area of Asi/a -illage where the be)roc( )i,s with the natural slo,e. Thegeneral tren) of roc( /ass howe-er is )i,,ing against the hill slo,e at a shallow angleBDrawing $"%&%P4%02.

.+4+4 Powerhouse 'rea

A surface ,owerhouse has been ,ro,ose) on the left ban( of "ahughat =hola below Asi/a-illage near Dagna/. A /e)iu/ slo,e consisting of collu-ial )e,osit will be exca-ate) to for

the construction of the ,owerhouse. The ,owerhouse will be ,lace) as close to the stee, roc( face as ,ossible. The ,hllite roc( in ,owerhouse area is gre E )ar( slightl E /o)eratelweathere) fine graine) soft E /e)iu/ strong ,hllite.

Photo 5+3 Pensto%/ ali#nment, powerhouse area loo/in# downstream 7rom 'in#ar Vir

The roc( /ass classification accor)ing to 'ieniaws(iHs roc( /ass rating sste/ in)icates the"7" -alue to be a,,roxi/atel +* which shows that the roc( /ass is fair in >ualit. Thefriction angle an) cohesi-e ,ro,ert for this roc( /ass is suggeste) to be about * )egrees an)*00 =Pa res,ecti-el.

The bac( slo,e of the roc( /ass can be exca-ate) at a slo,e B5 4 1 0. E 1 1.2 for soft roc( an) 1 0.* E 1 0.; for har) roc(. Thus actual cut slo,e angle can be )eci)e) at the ti/e of


P#8"4#$S ST

"A4$&4AT =4#LA

P!ST#C= PP




exca-ation )e,en)ing on roc( /ass >ualit encountere). Successi-e benching is re>uire) withabout 1. / wi)e ber/ for e-er :./ height. Pattern roc( bolting an) shotcrete su,,ort shall bea))e) to increase the stabilit of cut slo,e. The roc( bolt length )e,en)s on roc( /ass >ualit

Bstrength jointing etc. an) cut slo,e height. For the feasibilit )esign ,ur,ose bolt )i/ensionhas been reco//en)e) to be as following

Dia/ater 2//Length /S,acing 1. E 2.0/ ,attern

Li(ewise the shotcrete thic(ness shall be 10 % 1c/.The tail water will be release) into "ahughat =hola. Allu-ial )e,osit is ,resent along ban(s of

the ri-er in this area.

.+6 Constru%tion Material

Possibilit of locating areas with ,otential )e,osits of construction /aterial within the ,rojectarea were in-estigate) an) stu)ie). t is foun) that the ,roject area is )eficit in construction/aterial es,eciall in the a-ailabilit of natural aggregate san) an) gra-el. #nl a few siteswithin the hea)wor(s area along 'agar =hola ha-e been i)entifie) that /a be suitable for

borrowing construction /aterial. The i)entifie) sites ha-e been shown in )rawing 7D%01.Sa/,ling an) testing of a-ailable /aterial shall be carrie) out in the next stage of the

geotechnical in-estigation.

n the hea)wor(s area stones an) s/all >uantities of san) are a-ailable in its natural for/ asallu-ial )e,osits along 'agar =hola. The exca-ate) /aterial fro/ the hea)wor(s an) the)esan)ing basin can also be use) as san) an) aggregate.

'etween the ,ro,ose) hea)wor(s an) the ,owerhouse sites "ahughat =hola flows along a -ernarrow an) stee, channel. This ,art of the (hola is not accessible. The ,ossibilit of construction/aterial existing in this stretch of ,roject area is thus -er negligible. 4owe-er s/all >uantitiesof natural aggregates can be obtaine) fro/ the hea)wor(s an) ,owerhouse sites at the ti/e of exca-ation.

The ,ossibilit of using tunnel /uc( as stones for ri,ra, an) /asonr structures also exists.There are a few ,otential locations for >uarring stones in the area of a)it ,ortals. Crushing

,lants can be establishe) to ,ro)uce coarse aggregates in such areas. Thus san) which is one of the /ajor construction /aterials /a ha-e to be trans,orte) fro/ further )ownstrea/ of the

,roject area such as fro/ the ban(s of the =aligan)a(i "i-er. San) an) natural aggregates arefoun) in abun)ance along the =aligan)a(i "i-er -alle. The suitabilit of the /aterial shoul)howe-er be confir/e) ,rior to using such /aterial.

.+- 8umpin# ; Mu%/ 8isposal !ites

During the construction of the ,roject the exca-ation of the hea)race tunnel the surge shaft the ,enstoc( anchor bloc(s an) sa))le su,,orts an) ,owerhouse will ,ro)uce an a,,reciable>uantit of exca-ate) /aterial as /uc(. 'oth surface an) sub%surface exca-ate) /aterial re>uire





geologicall a,,ro,riate locations for their )is,osal. As far as ,ossible these areas shoul) belocate) as near as ,ossible to the location fro/ the tunnel outlet a)it ,ortals an) exca-ation

,oints to re)uce the haulage )istance an) ti/e.

The /aterial exca-ate) fro/ the hea)wor(s site can be ,artl use) for ,ro)ucing construction/aterial such as san) aggregate an) stones. 'oul)ers can also be use) for ri, ra, an) ri-er training wor(s. t is en-isage) that the construction of the hea)wor(s for this ,roject willin-ol-e the construction of relati-el s/aller structures an) the a/ount of exca-ation is alsoex,ecte) to be relati-el s/all. Thus the s/all >uantities of exca-ate) /aterial for theconstruction of the hea)wor(s can be )u/,e) along the ban(s of 'agar =hola.

Dis,osal of /uc( fro/ the exca-ation of both the a)its will be )one in the -icinit of ,ortal area

of these a)its. A)it !o. 1 is locate) in the -icinit of Dar/ija -illage an) the A)it !o. 2 islocate) in the -icinit of Al)u -illage. 'oth of these areas are consi)ere) to be suitable for the)is,osal of the tunnel /uc( fro/ the res,ecti-e tunnel faces. Dis,osal of the exca-ate) /aterialfro/ the ,enstoc( align/ent area Bachor bloc(s sa))le su,,orts the surgeshaft an) the tunneloutlet area /a re>uire the ac>uisition of so/e lan) in these areas.

.+10 Con%lusions and Re%ommendations

The following conclusions an) reco//en)ations ha-e been /a)e on the basis of the geologicalan) geotechnical stu)ies carrie) out for the ,roject.

.+10+1 Con%lusions

.+10+1+1 $eadwor/s

The hea)wor(s for $"4P consist of two ,arts a )i-ersion weir for 'agar =hola an) aninterconnecting structure to con-e the water fro/ the tailrace of "74P. 'oth of thesestructures will be locate) across 'agar =hola. All of these structures as well as other relate)structures are ex,ecte) to be foun)e) on allu-ial soil.

.+10+1+2 8esandin# asin

The )esan)ing basin will be foun)e) ,artl on allu-ial an) ,artl on collu-ial )e,osits. 'oth of these are boul)er /ixe) soil. The thic(ness of the collu-ial )e,osit is esti/ate) to be about /an) hence the )esan)ing basin will be foun)e) on boul)er /ixe) soil.

.+10+1+ $eadra%e Tunnel and 'dit

The total length of the hea)race tunnel is ex,ecte) to be +;00 / an) the total length of the twoconstruction a)its is ex,ecte) to be a,,roxi/atel +00 /. Thus the total length of theun)ergroun) structures for the ,roject will be about 200 /. The roc( /ass along the hea)racetunnel has been )i-i)e) into fi-e classes E "1 to " with corres,on)ing reco//en)e) su,,ortt,es fro/ S1 to S.

The construction a)its will be ,ro-i)e) with te/,orar initial su,,orts onl to ,ro-i)e safewor(ing con)ition )uring the construction ,erio).





.+10+1+5 !ur#e !ha7t

The surge shaft is ,ro,ose) to be locate) on fair >ualit ,hllite roc( in the area of Asi/a

-illage. nterbe))ing of >uart9ite is ,resent in the ,hllite roc(.

.+10+1+? Pensto%/ ali#nment

The ,enstoc( ,i,e will be lai) on surface in the area of Asi/a -illage fro/ the en) of hea)racetunnel to the ,owerhouse. 7ajor stretch of the ,enstoc( ,i,e will be locate) on collu-ial soil.#nl a s/all stretch at )ifferent ,arts es,eciall in stee,l slo,ing sections the anchor bloc( an) sa))le will be foun)e) on be)roc( % ,hllite.

.+10+1+. Powerhouse

The ,owerhouse will be foun)e) on ,hllite roc( on the left ban( of "ahughat =hola.

.+10+2 Re%ommendations 7or !u !ur7a%e >eolo#i%al :n*esti#ation

The following are the reco//en)ations that ha-e been /a)e on the basis of the geological an)geotechnical sur-e an) stu).

$eadwor/s area

• Drilling is reco//en)e) to confir/ the )e,th )own to the le-el of the be)roc( an) toconfir/ the nature of the /aterial an) roc( at the ,ro,ose) weir site an) the )esan)ing

basin area. A )e,th of *0 / of )rilling has been reco//en)e) for the in-estigation at thehea)wor(s site.

• t is reco//en)e) that )rilling be acco/,anie) b in%situ ,er/eabilit an) strength testssuch as the SPT DCPT to (now the ,er/eabilit con)itions an) the geotechnical

,ro,erties of the soil an) roc(.• &eo,hsical sur-e electricit resisti-it to/ogra,h is reco//en)e) to exa/ine the

subsurface strata between the hea)wor(s an) the hea)race tunnel inta(e ,ortal areas.

!ur#e sha7t and pensto%/ area

• Drilling is reco//en)e) in the ,ro,ose) surge shaft location to in-estigate the )e,th of the o-erbur)en /aterial an) other relate) tests. t is reco//en)e) that the surge tan( area be in-estigate) b )rilling )own to a )e,th of *0 /.

• &eo,hsical in-estigation such as electricit resisti-it to/ogra,h will be re>uire) to(now the nature of the sub surface /aterial along the ,ro,ose) align/ent of the ,enstoc( align/ent an) to confir/ the geotechnical ,ro,erties of this subsurface /aterial for slo,estabili9ation ,ur,oses.

Powerhouse area





• Driling is reco//en)e) in the ,ro,ose) ,owerhouse area to exa/ine the nature of the/aterial for the )esign of the foun)ation. t is rco//en)e) that the ,owerhouse area bein-estigate) with two )rill holes each ha-ing a )e,th of *0 /.

• &eo,hsical in-estigation such as electricit resisti-it to/ogra,h will be re>uire)along the ,owerhouse an) the tailrace axis to confir/ the geotechnical ,ro,erties of thesubsurface /aterial for the ,ro,er )esign of the foun)ations.

The ,ro,ose) electrical resisti-it lines for the hea)wor(s an) ,owerhouse areas are shown inDrawings $"%"%01 an) 02.

:nsitu and laoratory tests on soil and ro%/ sample

Detaile) in-estigations consisting of test ,itting sa/,ling of soil an) roc( sa/,les for laborator tests will be re>uire) to (now the /echanical ,ro,erties of the soil an) the roc( for the )esign of the foun)ations as well as to chec( the suitabilit of the construction /aterials.




Upper Rahughat Hydroelectric Project Alternati"e Studies

4+0 'T)RN'T:V) !T"8:)!

4+1 :ntrodu%tion

The stretch of the align/ent of $,,er "ahughat =hola ,ro,ose) for ,ower )e-elo,/ent is fairlstee, an) the to,ogra,h in general is >uite rugge). As )escribe) in the ,re-ious cha,ters it isen-isage) that flows fro/ 'agar =hola will also contribute in the generation of ,ower not onl

b contributing flows for the generation of ,ower -ia the ,owerhouse of $,,er "ahughat 4P but also b /eans of constructing a s/all ,owerhouse in the hea)wor(s area of this ,roject. Dueto the necessit of these arrange/ents the laout for $,,er "ahughat =hola 4)roelectricProject is slightl )ifferent fro/ an arrange/ent ,ro,ose) for con-entional h)ro,ower ,rojects.

The ,roject will thus consist of a hea)wor(s structure locate) at the confluence of "ahughat=hola an) 'agar =hola.The ,ro,ose) hea)wor(s structure for $,,er "ahughat 4)roelectricProject basicall consists of structures interconnecting the tailrace of "ahughat 7angale4)ro,ower Project B"74P a ri-er )i-ersion structure a )esan)er an) a s/all ,owerhouse

for 'agar =hola an) the inta(e for $,,er "ahughat 4)roelectric Project B$"4P. Thetailwater fro/ "74P is ,ro,ose) to be brought across 'agar =hola to its left ban( si)e withthe ,ro-ision of a cut an) co-er box cul-ert structure. The )ischarge fro/ 'agar =hola will also

be )i-erte) with the ,ro-ision of a s/all weir across the (hola as well as a )esan)er an) a ,owerhouse for ,ower generation before being )i-erte) into a collection cha/ber locate) just before the inta(e ,ortal for the hea)race tunnel of $"4P. The cut an) co-er box cul-ertcarring the )ischarge fro/ the tailwater of "74P will also be connecte) to this collectioncha/ber so that the flows fro/ both "74P an) 'agar =hola tailrace can collecti-el berelease) into the inta(e ,ortal of the hea)race tunnel for $"4P.

The flow fro/ the collection cha/ber will be con-ee) to the surgetan( locate) at an

a,,roxi/ate ele-ation of L 1;0 /asl. The surgetan( will be connecte) to the surface ,owerhouse b /eans of a ,enstoc( that is locate) un)ergroun) at it u,strea/ an) )ownstrea/en)s. The ,enstoc( align/ent will surface in the /i))le of the align/ent. The ,owerhouse will

be locate) on the left ban( of "ahughat at an a,,roxi/ate ele-ation of L 11:.;2.

As /entione) earlier "ahughat 7angale 4)ro,ower Project lies i//e)iatel u,strea/ of $,,er "ahughat 4)roelectric Project. The ,owerhouse of this ,roject has been ,ro,ose) on theright ban( of 'agar =hola a tributar of "ahughat =hola about 10 / u,strea/ fro/ theconfluence of "ahughat "i-er an) 'agar =hola. Due to its location $,,er "ahughat4)roelectric Project can be )e-elo,e) in two was one as an in)e,en)ent ,ower ,roject withan in)e,en)ent hea)wor(s along the "ahughat "i-er an) the secon) as a casca)e ,roject of

"ahughat 7angale 4)ro,ower Project.


Chapter !e*en

'T)RN'T:V) !T"8:)!




#n this basis the alternati-e arrange/ents consi)ere) for the ,roject are as follows

• Consi)eration of a casca)e )e-elo,/ent instea) of an) in)e,en)ent ,roject• Consi)eration of ,ro)ucing ,ower locall at 'agar =hola instea) of ,ro-i)ing it with

energ )issi,ation structures• The choice of the con-eance sste/ fro/ the inta(e at "ahughat =hola u,to the

,ro,ose) surgetan(• Location an) choice of the ,owerhouse

4+2 Cas%ade 8e*elopment

f "ahughat 7angale was to be )e-elo,e) as an in)e,en)ent ,roject a se,arate hea)wor(s witha )esan)er woul) ha-e to be built across "ahughat so/ewhere )ownstrea/ of the confluence of "ahughat an) 'agar =hola. Since there is a ,ossibilit of using the )ischarge fro/ the tailraceof "ahughat 7angale 4P buil)ing a se,arate ha)wor(s woul) result in unnecessar extracosts. Further/ore o,ting for the first wa of )e-elo,/ent woul) result in the loss of hea) thatexists between the ,ro,ose) ,owerhouse of "ahughat 7angale an) the su,,ose) location of thehea)wor(s of $,,er "ahughat 4P if it were built.

Alternati-el the secon) wa to )e-elo, the ,roject woul) be to )i-ert the tail water of "ahughat 7angale 4)ro,ower Project into the hea)race tunnel of $,,er "ahughat

4)roelectric Project b constructing an interconnection sste/ at the ,owerhouse of "ahughat7angale 4)ro,ower Project at 'agar =hola. This sche/e will not nee) the construction of ase,arate hea)wor(s an) )esan)ing basin. 4owe-er in or)er to collect the )ischarge fro/ 'agar =hola a s/all )i-ersion weir an inta(e an) a )esan)er will be nee)e) at the 'agar =holau,strea/ fro/ the ,owerhouse of "ahughat 7angale ,roject. The )ischarge fro/ 'agar =holawill be a))e) to the )ischarge fro/ "ahughat 7angale in the collection cha/ber an) thencon-ee) to the hea)race tunnel of the ,roject.

t is >uite ob-ious fro/ the abo-e argu/ents that the secon) alternati-e is /uch /ore attracti-ein ter/s of cost as well as benefits. The secon) alternati-e has therefore been consi)ere) for theo,ti/i9ation stu) of the ,roject.

The onl )rawbac( of this sche/e is that $,,er "ahughat ,roject cannot be co//issione) ,rior to the co//issioning of "ahughat 7angale Project.

As ,er the )iscussions hel) with the client an) )ue to the ob-ious benefits attribute) to thecasca)e )e-elo,/ent o,tion the feasibilit stu) has been carrie) out for this o,tion. #-erall

,roject laout showing the Casca)e De-elo,/ent of two ,rojets is shown in Drawing !o. $"%PL%02.

4+ Power >eneration 7rom a#ar Khola

The choice for the secon) alternati-e is further strengthene) b the )ecision to utili9e the flowfro/ 'agar =hola for the ,ro)uction of ,ower locall as well as ,ro)uction of ,ower b a))ingit to the $,,er "ahughat 4P.





The )ecision to ta, the flow fro/ 'agar =hola for ,ower generation re>uires the construction of a )i-ersion weir with a )esan)er. 'agar =hola at this location is fairl stee, an) will re>uire ,ro/inent energ )issi,ation structures to con-e the flow fro/ the )esan)er to the collectioncha/ber before it is con-ee) to the hea)race tunnel. The )ifference in hea) a/ounts to so/e

1 /. t was agree) between the client an) the consultant that instea) of ,ro-i)ng energ)issi,ation structures it woul) be /ore a,,ro,riate to )e-elo, this stretch of the configurationfor the ,ro)uction of energ. n or)er to )o this the construction of a s/all ,owerhouse withtwo Francis Turbines an) a ,air of ,enstoc( ,i,es fro/ the en) of the )esan)er u, to the

,owerhouse woul) be re>uire) instea) of the construction of the energ )issi,ation structures.The arrange/ent for the rest of the structures woul) re/ain the sa/e. t is >uite ob-ious that the

benefit fro/ this arrange/ent far outweighs the o,tion of wasting the ,otential b theconstruction of energ )issi,ation structures which woul) also re>uire a consi)erable a/ount of cost.

t was thus )eci)e) that arrange/ents shoul) be /a)e to ,ro)uce ,ower fro/ 'agar =holalocall before )i-erting its flow into the collection cha/ber an) then on to the hea)race tunnelof $"4P.

A )etaile) )escri,tion of this arrange/ent is gi-en in Section <.2 of this re,ort.

4+5 The Choi%e o7 the Con*eyan%e !ystem

4)ro,ower ,rojects usuall consist of either a ,ressure ? free flow tunnel or an o,en canalstructure as the hea)race con-eance structure. De,en)ing u,on the nature an) /aterial of theterrain one of the abo-e choices woul) be a,,ro,riate in ter/s of to,ogra,h as well asecono/.

f the terrain is relati-el flat along the align/ent of the con-eance an o,en canal coul) be ,referre) in the econo/ic ter/s. 4owe-er in the absence of such terrain a con-eance willusuall consist of an un)ergroun) tunnel. $n)ergroun) tunnels are usuall ,ressuri9e) instea)of free flowing.

n the case of $,,er "ahughat =hola 4)roelectric Project se-eral conce,tual co/,arisionswere /a)e regar)ing the a,,ro,riate choice for the con-eance. The terrain along the ,ro,ose)align/ent for the con-eance fro/ the "ahughat hea)wor(s u, to the 'agar =hola hea)wor(s is>uite stee, an) unsuitable for an o,en canal. An un)ergroun) tunnel has thus been ,ro,ose) for this ,art of the align/ent.

4+? o%ation and Choi%e o7 the Powerhouse

The location for the ,owerhouse is to a large extent )ictate) b the terrain. Preferabl a surface ,owerhouse is usuall ,ro,ose) the construction /etho) for which is usuall /ore si/,le an)

econo/ic. Co/,lications in ter/s of access an) )rainage tunnels along with co/,licationsregar)ing the soun)ness of the >ualit of the roc(s are usuall encountere) in un)ergroun) ,owerhouses. These co/,lications usuall ten) to /a(e the ,owerhouse /ore ex,ensi-e an)co/,licate) to construct.





$n)ergroun) ,owerhouses are onl consi)ere) when no suitable areas are a-ailable for thelocation of a surface ,owerhouse. A surface ,owerhouse has thus been ,ro,ose) for this ,roject.




Upper Rahughat Hydroelectric ProjectProject &pti$i'ation

6+0 PRO@)CT OPT:M:J'T:ON

6+1 :ntrodu%tion and O&e%ti*e

4)ro,ower is the /ajor source of electricit generation in !e,al. The )e/an) is characteri9e)

b the )istinct ,ea( )e/an) )uring the e-ening an) the co/,arati-el s/all )e/an) in the/orning. These ,ea(s beco/e ,ro/inent in the winter season. At the sa/e ti/e the flow in theri-er )ecreases consi)erabl. Although fro/ the loa) characteristic ,oint of -iew a storage

,roject woul) be nee)e) to stri(e a balance between the su,,l an) )e/an) es,eciall )uringthe winter ,ea( the ex,ensi-e nature of a storage ,lant cou,le) with the en-iron/ent i/,actscause) b it the construction of storage ,lants has been li/ite) to one at the ,resent. The run off the ri-er ,lant an) ,on)age run off the ri-er ,lant ha-e been consi)ere) as a /ore affor)ableo,tion for /e)iu/ range ,ower )e-elo,/ent b PP in !e,al.

The installe) ca,acit of a run of ri-er ,roject is usuall fixe) b o,ti/i9ing it on the basis of the to,ogra,h the ,ro-i)e) structures an) the econo/ic characteristics of the ,roject.

The ,rinci,le objecti-e of the o,ti/i9ation stu) was thus to o,ti/i9e the following ,rojectco/,onents

• The )esign )ischarge an) the corres,on)ing installe) ca,acit

• The )ia/eter of the /ajor ele/ents of the water con-eance sste/ co/,rising of

% 4ea)race tunnelY% Surge tan(Y an)% Penstoc(Y

6+2 Pro&e%t 8e*elopment !trate#y and 'lternati*e !tudy

$,,er "ahughat 4)roelectric Project is locate) -er close to "ahughat 4)ro,ower Project being )e-elo,e) b !e,al lectricit Authorit. !A has alrea) initiate) the i/,le/entation of this ,roject. A,art fro/ these two ,rojects another h)ro,ower ,roject is also being stu)ie) inthis localit along the "ahughat "i-er. t is "ahughat 7angale 4)ro,ower Project an) islicense) to an PP b the na/e of 7anju Achara. This ,roject lies i//e)iatel u,strea/ of $,,er "ahughat 4)roelectric Project. The hea)wor( of "ahughat 7angale ,roject is ,ro,ose)to be locate) at a ,lace calle) Dhar an) the ,owerhouse has been ,ro,ose) to be locate) on theright ban( of 'agar =hola about 10 / u,strea/ fro/ the confluence of "ahughat "i-er an)


Chapter )i#ht

PRO@)CT OPT:M:J'T:ON




'agar =hola. The ,roject area of $,,er "ahughat 4)roelectric Project is situate) i//e)iatela)jacent to an) in between two h)ro,ower ,rojects "ahughat 7angale 4)ro,ower Project atu,strea/ si)e an) !A "ahughat 4)ro,ower ,roject at the )ownstrea/ en).

Due to the -irtue of the location of this ,roject $,,er "ahughat 4)roelectric Project can be)e-elo,e) in two was one as an in)e,en)ent ,ower ,roject with in)e,en)ent hea)wor(s alongthe "ahughat "i-er an) the secon) as a casca)e ,roject of "ahughat 7angale 4)ro,ower Project. The location selecte) for the ,owerhouse for "ahughat 7angale 4)ro,ower Project isalong the right ban( of 'agar =hola. n general 'agar =hola can be consi)ere) as the boun)ar

between "ahughat 7angale 4P an) $,,er "ahughat 4P.

f "ahughat 7angale was to be )e-elo,e) as an in)e,en)ent ,roject a se,arate hea)wor(s with

a )esan)er woul) ha-e to be built across "ahughat so/ewhere )ownstrea/ of the confluence of "ahughat an) 'agar =hola. Since there is a ,ossibilit of using the )ischarge fro/ the tailraceof "ahughat 7angale 4P buil)ing a se,arate ha)wor(s woul) result in unnecessar extracosts. Further/ore o,ting for the first wa of )e-elo,/ent woul) result in the loss of hea) thatexists between the ,ro,ose) ,owerhouse of "ahughat 7angale an) the su,,ose) location of thehea)wor(s of $,,er "ahughat 4P if it were built.

Alternati-el the secon) wa to )e-elo, the ,roject woul) be to )i-ert the tail water of "ahughat 7angale 4)ro,ower Project into the hea)race tunnel of $,,er "ahughat4)roelectric Project b constructing an interconnection sste/ at the ,owerhouse of "ahughat7angale 4)ro,ower Project at 'agar =hola. This sche/e will not nee) the construction of ase,arate hea)wor(s an) )esan)ing basin. 4owe-er in or)er to collect the )ischarge fro/ 'agar =hola a s/all )i-ersion weir an inta(e an) a )esan)er will be nee)e) at the 'agar =holau,strea/ fro/ the ,owerhouse of "ahughat 7angale ,roject. The )ischarge fro/ 'agar =holawill be a))e) to the )ischarge fro/ "ahughat 7angale in the collection cha/ber an) thencon-ee) to the hea)race tunnel of the ,roject.

t is >uite ob-ious fro/ the abo-e argu/ents that the secon) alternati-e is /uch /ore attracti-ein ter/s of cost as well as benefits. The secon) alternati-e has therefore been consi)ere) for theo,ti/i9ation stu) of the ,roject.

Due to the nature of the )e-elo,/ent strateg of the ,roject the o,ti/i9ation of the )esign)ischarge an) the esti/ation of the o,ti/u/ installe) ca,acit of this ,roject will be carrie) out b consi)ering the fixe) )esign )ischarge of 7angale "ahughat Project ,lus the series of )ischarges on the basis of the flow )uration cur-e fro/ 'agar =hola for the )ifferent o,tions.The )esign )ischarge fro/ 7angale "ahughat ,roject is 12 /*?sec. The -arious )ischarges for the )ifferent o,ti/i9ation scenarios fro/ 'agar =hola will thus be a))e) to this )esign)ischarge to obtain the #,ti/u/ )esign )ischarge for this ,roject.

6+ 8esi#n 8is%har#e ; :nstalled Capa%ity Optimiation

The o,ti/i9ation of the ,lant installe) ca,acit is inherentl )one with the o,ti/i9ation of the)esign )ischarge. As this ,roject is ,ro,ose) to be )e-elo,e) as a casca)e ,roject of "ahughat





7angale Project the )esign )ischarge of "ahughat 7angale ,lus the )ischarge fro/ the 'agar =hola is use) to o,ti/i9e the )ischarge of the $,,er "ahughat Project. The )esign )ischargefro/ "ahughat 7angale ,roject has been fixe) at 12 / *?sec. 4ence to obtain the o,ti/u/

)esign )ischarge for $,,er "ahughat ,roject fixe) )ischarge fro/ the "ahughat 7angale ,roject ,lus -arious )ischarges fro/ 'agar =hola were consi)ere) for the )ifferent o,tions for the o,ti/i9ation stu).

n case of the o,ti/i9ation of the run%of ri-er sche/e the height of the )a/ /ini/u/ o,eratingle-el an) high floo) le-el are all irrele-ant to the )esign )ischarge. These ele/ents are /oreinfluence) b the general to,ogra,h of the )a/ site )esign floo) /agnitu)e an) the ri-er characteristics which are co//on to all installe) ca,acit o,tions. Therefore all the o,tionswere base) on the res,ecti-e )ischarge an) subse>uent h)raulic )esign of the water con-eance sste/ fro/ the ri-er inta(e to the ,owerhouse.

6++1 'ssumptions

n the ,rocess of carring out the o,ti/i9ation of the ,roject the /o)e of energ benefit whichcan be )eci)e) onl at the ti/e of the ,ower ,urchase agree/ent ,las a -ital role. n theabsence of a PPA the ,roject o,ti/i9ation exercise can be con)ucte) with the con-entional PPA/o)el use) for )o/estic su,,l. For the installe) ca,acit of u, to 2 78 !A has ,oste) the

energ ,rice offere) to the )e-elo,er for )r season an) wet season. For the installe) ca,acitabo-e 2 78 the a-erage energ rate is fixe) b assu/ing a 1O return on e>uit.

4ence the o,ti/i9ation stu) for this ,roject uses the following two conce,ts for calculating the benefits

• nerg rate s,lit into )r season an) wet season an)

• Flat energ rate for annul a-erage energ

The o,ti/i9ation of the ,lant installe) ca,acit was base) on the following assu/,tions

• Dr season corres,on)s to !e,ali /onth starting fro/ Poush to Chaitra BFour /onths an)

generation )uring re/aining eight /onths is ter/e) as wet season energ

• Poste) rate for the )r season energ is "s. :.00 ,er (8h where as that for wet season energ is

"s. +.00 ,er (8h.

• x,ecte) rate on return on e>uit is 1O

• The runners will be re,lace) after e-er 10 ears.

• A co/,ensation flow of 0.+: /*?s is re>uire) to be release) )ownstrea/ of the hea)wor(s. This

flow corres,on)s to a 10O of the /ini/u/ /onthl flow Bbase) on !e,ali Calen)ar.

• All energ benefits will be reali9e).





6++2 'pproa%h and Methodolo#y

The o,ti/i9ation of the )esign )ischarge was un)erta(en through a financial analsis.

Conce,tual laouts were )e-elo,e) for each alternati-e for which cost esti/ates were ,re,are).ach of the co/,onents of the con-eance sste/ was o,ti/i9e). The ,ower benefits were)eter/ine) for each alternati-e an) co/,are) with the corres,on)ing financial costs. The seriesof cost an) benefits were )iscounte) in or)er to esti/ate the ,resent -alues. The objecti-e is to)eter/ine the o,ti/u/ )esign )ischarge. The installe) ca,acit corres,on)ing to a )ischargeother than the o,ti/u/ )esign )ischarge woul) result in lower return on e>uit for fixe) energrates or higher energ rate for fixe) ex,ecte) return on e>uit.

The o,ti/i9ation ,roce)ure in this stu) follows the general a,,roach outline) below

• stablish a series of )ischarge o,tions base) on the h)rolog

• sti/ate the /ini/u/ o,erating le-el base) on the flushing re>uire/ent of the )esan)ing basin

an) the location of the ,ro,ose) surface )esan)er at 'agar =hola. This will be the sa/e for allo,tions. 4owe-er the o,erating le-el for the ,ower generation is base) on the tail water le-el of the "ahughat 7angale Project at the collection cha/ber where both the flow fro/ tail water of "ahughat 7angale ,roject an) )ischarge fro/ 'agar =hola inta(e are /ixe) an) is )ifferent for )ifferent o,tions.

• sti/ate the si9e of the free flow s,illwa an) un)er sluice Bbotto/ outlet to ,ass the )esign

floo) of 1100 ear an) chec( for floo) occurrence of 100 ear. This too will be co//on for all o,tions.

• sti/ate the )i/ensions of inta(e inta(e channel )esan)ing basins an) flushing structure for

each ca,acit o,tion at 'agar =hola

• #,ti/i9e the hea)race tunnel surge tan( ,enstoc( an) )ro, shaft for each ca,acit o,tion

• sti/ate the ,owerhouse an) tailrace )i/ensions for each ca,acit o,tion

• Pre,are the conce,tual laout an) )esign an) esti/ate the costs of the in)i-i)ual structures for

each ca,acit o,tion

• Deter/ine the )r season energ wet season energ an) a-erage annual energ an) esti/ate thecorres,on)ing benefit for each of the ca,acit o,tion.

• Co/,ute the return on e>uit assu/ing the energ rates an) co/,ute a-erage energ rate

assu/ing the ex,ecte) return on e>uit.

• Discharge corres,on)ing to highest return on e>uit is the o,ti/u/ )esign )ischarge in case the

energ rates are fixe) whereas )ischarge corres,on)ing to lowest energ rate is the o,ti/u/)esign )ischarge in case the ex,ecte) return on e>uit is fixe).

Laouts of the in)i-i)ual structures concei-e) in the o,ti/i9ation stu) /a -ar an) can be

/o)ifie) in the feasibilit )esign. 4owe-er the general laout an) the /ain conce,t of the ,roject will re/ain the sa/e. All )etails of #,ti/i9ation that inclu)es )esign cost esti/ationenerg co/,utation an) financial analsis of all o,tions are shown in Annex C.





6++ Ran#e o7 Options

n or)er to )eter/ine the o,ti/al installe) ca,acit it is necessar to stu) a range of ca,acities

within which the o,ti/al solution can be foun). Stu)ies of the "o" ,rojects in !e,al in)icatethat the o,ti/u/ ,lant ca,acit usuall lies in the range of *0O to 0 O of the exce)ence flow.To obtain the o,ti/u/ )esign )ischarge for the $,,er "ahughat ,roject fixe) )esign )ischargefro/ the "ahughat 7angale ,roject ,lus -arious exce)ence flows fro/ 'agar =hola areconsi)ere) in o,tions stu). These are shown Table ;%1. The corres,on)ing ,lant ca,acities asliste) in Table ;%1 are consi)ere) to be a)e>uate to )efine the tren) of the benefit cost analsis.

Tale 621 Ran#e o7 Options

#,tions Percentage

xce)ence

DesignDischarge

fro/"ahughat7angale

B/*?s

"ate)Discharge

fro/ 'agar =hola B/*?s

Co/bine)Discharge

B/*?s

Ca,acit consi)ere)B78

A *0O 12.0 .0: 1;.0: ;.0' +0O 12.0 *.1 1.1 0.0C 0O 12.0 2.+: 1+.+: +:.0D 0O 12.0 1.:1 1*.:1 ++.0

The installe) ca,acities gi-en abo-e were )eri-e) for each of the flows assu/ing an o-erallefficienc of the turbine generator an) transfor/er e>ui-alent to ;;.+1O. The se,arateefficiencies are shown in Table ;%2. The total hea) loss in the water con-eance sste/ wasesti/ate) on the basis of the o,ti/u/ si9e of the tunnels an) ,enstoc(.

Tale 622 )77i%ien%ies

S.!o. >ui,/ent fficienc1 Turbine <* O2 &enerator <; O* Transfor/er <: O

#-erall ;;.+1O

6+5 Ri*er Flows

The ca,acit an) energ ,otential of a ,articular o,tion is )e,en)ent on the ri-er flows. The

/ean /onthl flows at the inta(e sites of "ahughat 7angale ,roject at "ahughat "i-er an)'agar =hola are shown in Table ;%*. These flows are use) in the co/,utations of )r seasonenerg wet season energ an) a-erage annual energ.





To /aintain a>uatic life in the )ewatere) reach of the ri-er 10O of the /ini/u/ /onthla-erage flow fro/ each ri-er totaling to 0.+: cu/ecs is ,ro,ose) to be release) fro/ thehea)wor(s. This has been )e)ucte) fro/ the ri-er flows while assessing the ca,acit an) energ

,otential of the )ifferent o,tions.

Tale 62 '*era#e Monthly Flows

)n#lish

Month

'*era#e Monthly

Flows 7rom

Rahu#hat Ri*er at

:nta/e o7

Rahu#hat

Man#ale $)P

<m;s=

'*era#e

Monthly

Flows

7rom

a#ar

Khola

<m;s=

Comined

Monthly

Flows 7rom

oth Ri*ers

<m;s=

Nepali

Month

Comined

Monthly

Flows

7rom oth

Ri*ers

<m;s=

@anuary *.: 1.*: .1* aisa/h <.+Feruary *. 1.10 +.: @estha 1.:*

Mar%h *.1 1.1< +.* 'sar 2+.0'pril +.+ 1.;0 .++ !hrawan *0.02May 10.2; *.*< 1*.: hadra 2:.:2@une 22.:< :.2< 1<.; 'shwin 1<.:@uly .22 1.2; 2:.0 Karti/ 11.<<

'u#ust +.:1 1;.;2 *1.1+ Mansir :.0+!epteme

r

+2.:* 11.212*.*

Poush

.1

O%toer 12.:* +.0< 1.+1 Ma#h +.;No*eme

r

.<0 2.*;.2

Fal#un

+.:8e%emer +. 1.0 .2 Chaitra .1

'nnual 20.+ .:< 1*.<* 'nnual 1*.<*

6+5+1 Minimum Operatin# e*el and Tail 9ater e*el

Since $,,er "ahughat ,roject a casca)e )e-elo,/ent of "ahughat 7angale Project the/ini/u/ o,erating le-el for all o,tions )e,en)s on the Tail 8ater Le-el of "ahughat 7angaleProject. 'ase) on these criteria the 7ini/u/ #,erating Le-el for all o,tions was fixe) at an

ele-ation of 12.0 /asl accor)ing to the Tail 8ater Le-el of "ahughat 7angale 4P.

The setting of the turbine for the ,owerhouse for $,,er "ahughat 4P has been base) on awater le-el corres,on)ing to the 1100 ear floo). The calculation of the ,otential gross hea) for





the esti/ation of the energ generation is therefore also base) on this ele-ation. 'ase) on thisthe tail water le-el is fixe) at 11:;.0 /asl. Pelton turbines ha-e been ,ro,ose) for the ,roject)ue to the high hea). Since the )ifference in the calculate) ele-ation of the turbine centerline for

the )ifferent ca,acit o,tions is negligible co/,are) to the o-erall gross hea) of the ,roject L11;0 was use) as the centerline of the turbine for all of the ca,acit o,tions. This is 2 / higher than the tail water le-el. This le-el was therefore use) to calculate the gross an) effecti-e hea)sof the ,lant for all the ca,acit o,tions.

6+5+2 $i#h Flood e*el at a#ar Khola $eadwor/s

During the ti/e of floo)s the ri-er carries /ore )ischarge than the )esign )ischarge an) thewater le-el thus rises abo-e the /ini/u/ o,erating le-el. The si9ing of the free o-erflows,illwa an) the un)er sluice for all ca,acit o,tions are influence) /ore b ,hsical constraintsrelate) to the abilit to ,ass floo) flows an) ri-er gra)ient at the )a/ site than the res,ecti-e

)esign )ischarge. The free flow s,illwa without o,erating the un)er sluice is )esigne) to ,assthe )ischarge of 2*1.0 cu/ecs which corres,on)s to the floo) of 1100 ears return ,erio). Thefloo) le-el at the ti/e of 1100 ear return ,erio) will be 1;.0 /asl. During the e-ent of the100 ear floo) the high floo) le-el is esti/ate) to be 1<.:* /asl. The high floo) le-el is

use) to )esign the )ec( le-el of the )i-ersion weir an) other surface water con-eance structuresat the 'agar =hola hea)wor(s.

6+? Con%eptual ayout and 8esi#n

The $,,er "ahughat Project consists of a hea)wor(s structure at 'agar =hola to ta, the)ischarge fro/ 'agar =hola an interconnection sste/ at 'agar =hola to )i-ert the water fro/"ahughat 7angale 4P a collecting ,on) at 'agar =hola a hea)race tunnel a surge tan( asurface ,enstoc( an incline) )ro, shaft an) a surface ,owerhouse.

The hea)wor(s at 'agar =hola co/,rises of a )i-ersion weir to )i-ert flows into a surface)esan)er locate) on the left ban( of the (hola. The )esign flow is con-ee) to the )esan)er fro/an inta(e structure locate) a)jacent to the weir -ia the inta(e channel. The flow fro/ the)esan)er is then con-ee) to the collecting ,on) where the )ischarge fro/ the "ahughat7angale Project is /ixe). Si/ilarl the flow fro/ the ,owerhouse of "ahughat 7angale 4P iscon-ee) to the collecting ,on) locate) on the left ban( of 'agar =hola through a concrete box

cul-ert locate) across an) below the 'agar =hola. Discharges fro/ both 'agar =hola an)"ahughat 7angale 4P are collecte) in the collecting ,on) locate) on the left ban( of 'agar =hola Fro/ the collecting ,on) the )ischarge is con-ee) to the surface ,owerhouse -ia thehea)race tunnel surge tan( surface ,enstoc( an) incline) )ro, shaft.

The si9es of all in)i-i)ual structures for each ca,acit o,tion were co/,ute). The features of structures an) s,ecific )esign consi)erations for each of the /ain structures for each ca,acito,tion are elaborate) un)er their res,ecti-e hea)ings. The )esign of the structures an) other )etails of the o,ti/i9ation stu)ies are shown in Annex C.

6+?+1 8i*ersion 9eir at a#ar Khola

For all ca,acit o,tions the )i-ersion weir will be of concrete gra-it structure with gate) un)er sluice an) a free o-erflow ogee s,illwa section along the weir axis built across the ri-er





channel of 'agar =hola. The )i-ersion weir will be foun)e) on allu-ial be). 4owe-er curtaingrouting is ,ro,ose) along the axis of the )a/.

As /entione) abo-e the si9ing of the free o-erflow s,illwa an) the un)er sluice for allca,acit o,tions are influence) /ore b ,hsical constraints relate) to the abilit to ,ass floo)flows ri-er gra)ient at the weir site an) stabilit of the section than the res,ecti-e )esign)ischarge. Therefore the si9e of the )i-ersion weir will be the sa/e for all ca,acit o,tions.

Following )esign criteria were use) in the )esign of the )i-ersion weir an) stilling basins

• base) on the in-ert le-el of the inta(e an) 7ini/u/ #,erating le-el of 1 /asl the crest

ele-ation of the free o-erflow s,illwa was fixe) at 1 /asl

• The free o-erflow s,illwa is )esigne) for the 1100 ear floo).

• the un)er sluice will be (e,t at 1*. /asl 1.0 / below the in-ert le-el of the inta(e an) willha-e a ca,acit to ,ass the annual floo) at 7#L.

• the )ec( le-el of the weir will be base) on the 7axi/u/ Floo) Le-el corres,on)ing to the

100 ears floo)

• the sha,e of the o-erflow crest an) the ca,acit of the s,illwa are )esigne) in accor)ance with

the reco//en)ations of the $nite) States 'ureau of "ecla/ation

The )i-ersion weir has been )esigne) on the basis of the abo-e assu/,tions. The )i-ersion weir will ha-e * /eter wi)e gate) un)er sluice at left ban( a)jacent to the inta(e an) a 1 /eter wi)efree o-erflow ogee s,illwa section along the re/aining wi)th of the ri-er channel. The un)er sluice will be e>ui,,e) with a * / wi)e b 2. / high -ertical lift gate.

6+?+2 Ri*er :nta/e at a#ar Khola

To )i-ert the water fro/ )i-ersion weir to the )esan)er an inta(e is ,ro,ose) on the left ban(.The inta(e of each o,tion was )esigne) to ,ass the res,ecti-e )esign flows at their

corres,on)ing /ini/u/ o,erating le-el with a flow -elocit of 0.: /?sec. Dec( le-el of inta(ein all o,tions are (e,t at 1:0 /asl which is abo-e the 4FL corres,on)ing to 100 ears floo).Fro/ the /ain inta(e the )ischarge is con-ee) to the )esan)er -ia the inta(e channel with a)ro, structure ha-ing -ariable lengths. The )ro, structure is ,ro-i)e) )ue to the )ifference in thewater le-el at the inta(e to the water le-el at collecting cha/ber. Table ;%+ gi-es the features of the inta(e an) inta(e channel for each ca,acit o,tion.

Tale 625 Features o7 :nta/e 7or )a%h Option

Descri,tion ? #,tions A ' C D !o of nta(e #,enings 1 1 1 1Design Discharge /*?sec .0: *.1 2.+: 1.:1Clear 8i)th of each inta(e in / *.0 *.0 *.0 *.0





6+?+ 8esandin# asin at a#ar Khola

De,en)ing on the )ischarge a surface )esan)ing basin with one or /ore cha/bers is consi)ere)

for each o,tion. The effecti-e )e,th an) wi)th of the basin were fixe) at *. / an) *.0 /res,ecti-el but the length of the )esan)er is )esign to extract <O of the 0.20 // )ia/eter ,articles at the /ini/u/ o,erating le-el.

The result of the h)raulic )esign calculations for all of the ca,acit o,tions are gi-en inA,,en)ix ' an) Table su//ari9es the /ain features of the )esan)ing basins for the )ifferento,tions. The )esan)ing basin for each o,tion is )esigne) for their res,ecti-e )esign )ischarge.The )esan)ing basin is )esigne) fro/ concentration a,,roach using Ca/,Hs re/o-al factor Bbase) on cur-es assu/ing a /ean se)i/ent concentration of 2*;0 ,,/. Due to theuna-ailabilit of se)i/ent )ata grain si9e )istribution of 7arsang)i "i-er at Phalia SanguB)a/ site of 7i))le 7arshang)i 4P was use) for this exercise. Fall -elocit of the ,articles

is esti/ate) for >uart9 s,heres in water at 1 )egree centigra)e. 4ori9ontal flushing ,roce)urethrough the flushing con)uit was assu/e) for all the cases.

Tale 62? Features o7 the 8esandin# asins 7or )a%h Capa%ity Option

Descri,tion ? #,tions A ' C D

!o of 'asin * 2 1 1ffecti-e )e,th of the 'asin in / *. *. *. *.

!u/ber of cha/ber in the 'asin 1 1 1 2ffecti-e wi)th of the Cha/ber in / *.0 *.0 *.0 *.0ffecti-e length of the 'asin in / + +0 ; *

6+?+5 Con%rete o( Cul*ert

The water fro/ the ,owerhouse of "ahughat 7angale is con-ee) to the $,,er "ahughat -ia acut an) co-er concrete box cul-ert. The )esign )ischarge of the box cul-ert for all o,tions is thesa/e an) is 12 /*?sec. Part of the box cul-ert crosses 'agar =hola. A,,roxi/atel 20 / of the

box cul-ert ,asses below the ri-er an) will nee) to be ,rotecte) fro/ the ri-er b two laers of 1. / thic( ,lu/b concrete an) a laer of 0. / thic( structure concrete. t will also be ,rotecte)

b u,strea/ an) )ownstrea/ concrete a,rons. These a,rons will consist of 0. / thic( ,lu/bconcrete. The total length of the box cul-ert is 2 / an) will ha-e internal )i/ensions of *. /

b *./.

6+?+? Colle%tion Chamer

8ater fro/ "ahughat 7angale will be con-ee) to the collection cha/ber locate) on the left ban( of the ri-er -ia a box cul-ert an) -ia a )esan)ing basin. The 7ini/u/ #,erating Le-el atthe collection cha/ber is fixe) with res,ect to tail water le-el of "ahughat 7angale which is12 /asl. 7#L is fixe) at 12 /asl for all o,tions. 8ater fro/ collection cha/ber iscon-ee) to the hea)race tunnel. The hea)race tunnel will be a ,ressure tunnel an) will the nee)-ortex hea) for safe h)raulic o,erating con)itions. The collection cha/ber has been )esigne)





to ,ro-i)e this -ortex hea). The /ini/u/ wi)th of the collection cha/ber was (e,t e>ui-alentto / or a wi)th base) on the wi)th of the 'agar =hola )esan)ing basin of the res,ecti-eo,tion whiche-er was higher. The )i/ensions of the collection cha/ber for each ca,acit

o,tions are ,resente) in Table ;% below

Tale 62. Features o7 Colle%tion Chamer

Descri,tion ? #,tions A ' C DLength 8i)th an) De,th in / 1;?10?; 1:.?.?:.

10.*??:.+ ;.<??:.+

6+?+. $eadra%e Tunnel, Pensto%/ and 8rop sha7t

The water con-eance sste/ of the ,roject consists of hea)race tunnel surface ,enstoc( followe) b )ro, shaft before it reaches to the surface ,owerhouse. The hea)race tunnelconnecting the ,ower inta(e at its u,strea/ en) an) the surge tan( at the )ownstrea/ en) isa,,roxi/atel +.; (/ long. The section of the hea)race tunnel assu/e) for the o,ti/i9ation of the tunnel )ia/eter will be circular in sha,e. The o,ti/i9ation ,roce)ure for each o,tion was

,erfor/e) on the basis of the following assu/,tions su//ari9e) in Table ;%:.

Tale 624 )%onomi% Parameters used in Optimiation

Para/eter 5aluecono/ic Life ti/e 2 earsConstruction Ti/e for waterwas + ear Discount "ate 10ODr Season nerg "s. :.00 ,er (8h8et Season nerg "s. +.00 ,er (8h

The construction cost co/,rises of the )irect cost onl. #,ti/i9ation of the hea)race tunnel was)one b using the in%house co/,uter ,rogra/ )e-elo,e) in a s,rea)sheet. The o,ti/i9ations for

all cases were carrie) out se,aratel. t was assu/e) that the /ajor length of the tunnel will beunline).

A co/bination of surface ,enstoc( /a)e u, of /il) steel ,i,es an) a )ro, shaft has been ,ro,ose) to )i-ert the water to the turbines fro/ the surge tan(. The initial ,art of the ,enstoc( will be locate) on the surface. This ,art is :* / long. Due to the ,resence of a stee, cliff 20*/ long incline) )ro, shaft is ,ro,ose) at the )ownstrea/ ,art of the ,enstoc( reaching thesurface ,owerhouse. These ,enstoc(s are o,ti/i9e) for all o,tions. The results of theo,ti/i9ations of the hea)race tunnels an) ,enstoc(s for each case are attache) in Annex C.Table ;%; shows the /ain features of the o,ti/u/ )ia/eters for the )ifferent tunnel sections an)ca,acit o,tions.

Tale 626 Features o7 $eadra%e Tunnel, !ur7a%e Pensto%/ and !teel ined 8rop !ha7t





Descri,tion ? #,tions A ' C D

Design )ischarge in /*?sec 1;.0: 1.1 1+.+: 1*.:1

#,ti/u/ finishe) )ia. of $nline)4ea)race Tunnel in / +.* +.0 *.< *.;

#,ti/u/ finishe) )ia. of Surface ,enstoc( an) incline) steel line) )ro,shaft in /Thic(ness of Steel in //

2.:10

2.10

2.10

2.10

The hea)race tunnel is +.; (/ long an) is assu/e) to be ,artl unline). t has two inter/e)iateconstruction a)its ha-ing lengths of 1; an) 21* /. The roc( /ass along the hea)race tunnelhas been )i-i)e) into fi-e classes "1 to " with corres,on)ing su,,ort t,es fro/ S1 to S.Percentage of the tunnel length for the S1 to S su,,ort sste/ reco//en)e) on the basis of thefiel) in-estigation an) utili9e) in the tunnel costing are . 2*. 2:.10 2<.*0 an) 1*.res,ecti-el.

A surge tan( is ,ro-i)e) at the en) of the hea)race tunnel. t is followe) b a *< / long surface ,enstoc( 1<0 / long incline) steel line) )ro, shaft an) / long hori9ontal steel line) ,ressure tunnel. The steel line) ,ressure tunnel will be branche) off to fee) the two turbineunits.

6+?+4 !ur#e Tan/

The ,hsical )i/ensions of the surge tan( ha-e been )eter/ine) using the Tho/a criteria for h)raulic stabilit. The si9e of the surge tan( has been fixe) so that it is as s/all as ,ossibleco//ensurate with construction constraints. The surge tan( will be o,en at the to,. Table <su//ari9es the )i/ensions of the surge tan( for the )ifferent ca,acit o,tions.

Tale 62- )stimated 8iameter o7 !ur#e Tan/

Descri,tion ? #,tions A ' C DFinishe) Dia/eter of Surge Tan( in / 11.0 10. 10.0 10.04eight of the Surge Tan( in / 2:. 2:.0 2:.0 2.+

6+?+6 Powerhouse and Tailra%e

The ,owerhouse will be an enclose) structure of reinforce) concrete substructure with gableroof. The ,owerhouse will be foun)e) entirel on be) roc(. The bac( slo,e for the ,owerhouse

will be benche) an) cut to an o-erall slo,e of 15 0.*4 with 1 c/ thic( shotcrete an) / longroc( bolt on the slo,e surface to assure stabilit on the be)roc(.





The ,owerhouse for all ca,acit o,tions contains two Pelton units an) all /iscellaneouselectrical an) /echanical e>ui,/ent re>uire) for the o,eration an) /aintenance of the facilit.Selection of two units is for the o,ti/isation ,ur,ose onl an) coul) be change) in the

feasibilit )esign. The ,owerhouse contains the generating unit bas an erection area an) anunloa)ing area. The general )i/ensions of the ,owerhouse for all of the ca,acit o,tions areshown in Table ;%10.

Tale 60 Features o7 Powerhouse and Tailra%e Channel 7or )a%h Capa%ity Option

Descri,tion ? #,tions A ' C DLength of the Powerhouse in / + +* *< *8i)th of the Powerhouse in / 1 1 1+ 1+

The water co/ing out of the ,owerhouse after generation of ,ower will be channelle) bac( intothe "ahughat "i-er. The tailrace consists of concrete box cul-erts e/erging fro/ each uniti//e)iatel )ownstrea/ of the ,owerhouse an) con-erging into a single cul-ert.

6+?+- '%%ess Road

$,,er "ahughat 4)roelectric Project )oes not ha-e a /otorable access roa) at ,resent. Thenearest roa) hea) to this ,roject is an earthen roa) at =ha,sin)a)a originating fro/ &aleshor.This roa) is about (/ long. &aleshor lies about * =/ north of 'eni on the 'eni % 3o/so/roa). 'eni the )istrict hea) >uarter of 7ag)i District is accessible b a 1* (/ long gra-el roa)that originates fro/ 7al Dhunga on Po(hara 'aglung 4ighwa.

Since $,,er "ahughat 4P is a casca)e ,roject of "ahughat 7angale 4P it will beconstructe) onl after the construction of "ahughat 7angale 4P. The access roa) built for "ahughat 7angale ,roject fro/ =ha,sin)a)a shall be use) for the construction of $,,er "ahughat Project. 4owe-er a))itional ,roject roa) will be re>uire) to reach the ,owerhousesurge tan( an) the inlet ,ortals of the two construction a)it tunnels. For this about (/ ,rojectroa) is esti/ate) an) consi)ere) in the o,ti/i9ation stu). The cost of the access roa) in theo,ti/i9ation stu) is consi)ere) to be ta(en b "ahughat 7angale 4P. 4oweer this

assu/,tion woul) be change) in the feasibilit )esign an) cost esti/ation.6+?+10 Transmission ine

As /entione) in Section 1. there are three ,rojects along the stretch of "ahughat =hola wherethis ,roject is being consi)ere). "ahughat 7angale 4P being )e-elo,e) b PP 7anju Acharais locate) at the /ost u,strea/ ,art. This ,roject is i//e)iatel followe) b $,,er "ahughat4P for which this current stu) is being carrie) out. The thir) ,roject "ahughat 4P islocate) )ownstrea/ of $,,,er "ahughat 4P ,roject an) is currentl being )e-elo,e) b !Aan) this ,roject en-isages the construction of a trans/ission line fro/ its ,owerhouse u, to the

,owerhouse of 7o)i 4P. Since the construction of this !A "ahughat 4P ,roject has alrea)

been initiate) it is un)erstoo) that this stretch of the trans/ission line will be in ,lace in the near future. The stu) for "ahughat 7angale 4P en-isages that its ,ower e-acuation will be carrie)out fro/ its ,owerhouse u, to the ,owerhouse of "ahughat 4P being built b !A -ia a singlecircuit line an) fro/ here u, to the ,owerhouse of 7o)i 4P -ia another single circuit line. t is





also en-isage) that the secon) circuit fro/ the ,owerhouse of "ahughat 4P u, to the ,owerhouse of 7o)i 4P will ha-e the ca,acit to e-acuate the ,ower ,ro)uce) b both"ahughat 7angale 4P as well as $,,er "ahughat 4P. Cost of this secon) circuit is

consi)ere) in the trans/ission line of "ahughat 7angale 4P. The ,ower generate) b thisB$,,er "ahughat 4P ,roject can therefore be e-acuate) in the switchar) of "ahughat 4PBbeing built b !A the i/,le/entation of which has alrea) been starte) b !A. Therefore$,,er "ahughat 4P will re>uire the construction of onl a single circuit line u, to theswitchar) of "ahughat 4P.

The e-acuation of ,ower fro/ this ,roject will thus be carrie) out b constructing an ; (/ long1*2 (5 single circuit trans/ission line with ACS" 'ear con)uctors on steel lattice towers

between $,,er "ahughat an) "ahughat 4P. The ,owerhouse substation at $,,er "ahughat4P will ha-e two nu/bers of 11?1*2 (5 ste, u, three ,hase out)oor ,ower transfor/ers twonu/bers of 1*2 (5 transfor/er bas an) one nu/ber of 1*2 (5 line ba. Li(ewise one nu/ber

of 1*2 (5 trans/ission line ba shall be exten)e) at the switchar) of "ahughat 4P. Theabo-e trans/ission line arrange/ent is -ali) for all four ca,acit o,tions of the #,ti/i9ationStu). The co/,onent of trans/ission sche/e is shown in Table ;%11.

Tale 61 Transmission ine 'lternati*es

S. !o.

Detail $nit t $nit rate 7$SN Total a/ount 7$SN

1 1*2 (5 SC line with'A" con)uctor onlattice towers

(/ ; 0.0;0 0.+

2 1*2 (5 line ba nos. 2 0.: 1.1+* 1*2 (5 transfor/er ba nos. 2 0.+* 0.;

Total 2.+

Total cost of this sche/e is about $SD 2+0000.00. t has been consi)ere) that all necessarelectrical facilities )eter/ine) b !A for gri) connection will be ,ro-i)e) b $,,er "ahughat4P.

6+. )stimate o7 )ner#y and Capa%ity Potential

n or)er to esti/ate the ca,acit an) energ ,otential of the )ifferent o,tions being consi)ere) as,rea)sheet /o)el was )e-elo,e). Following are the assu/,tions /a)e for the esti/ation

• The full su,,l le-el of 12 /asl an) turbine setting at 11;0 /asl ,ro)ucing *:2 /eter of

gross hea).

• #-erall efficienc is ;.00O

• Pro,ortionate total hea) loss for -aring ,ower )ischarge to esti/ate net hea) for )ifferent

)ischarges.

• 7ini/u/ release of 0.+: /*?s corres,on)ing to the 10O of the /ini/u/ /onthl flow.

• The /o)el calculates the following ,ara/eters

• the installe) ca,acit





• the a-erage )r season energ

• the a-erage wet season energ

• the a-erage annual energ

The results of the esti/ates of ca,acit an) energ ,otential for all four o,tions are su//ari9e)in Table ;%12. Details of the energ calculation are gi-en in Annex C.

Tale 62 !ummary o7 Power and 'nnual )ner#y 7or 8i77erent 8esi#n 8is%har#e

#,tions $nitDesign Discharge B/*?s

16+04 1?+.1 15+54 1+41

nstalle) Ca,acit 78 ; 0 +: ++7axi/u/ Power 78 :.1: +<.* +.: +*.*;Annual Dr Season nerg BPoush to Chaitra

&8h +2.0; +2.0 +2.0 +2.0+

Annual 8et Season nergB'aisa(h to 7ansir

&8h 2:*.1 2+:.< 2*+.+1 22.+;

Annual A-erage nerg &8h *1.2+ 2<0.02 2:.+: 2:.2

For the esti/ation of the salable energ the sche)ule) an) unsche)ule) outage self consu/,tion an) trans/ission loss is esti/ate) to be ;O.

6+4 Cost )stimate

For the ,roject cost esti/ation of )ifferent ca,acit o,tions unit rates for /ajor wor( ite/s were base) on those use) for si/ilar h)roelectric ,rojects ,resentl un)er construction or recentlstu)ie) to feasibilit le-el in !e,al. These unit rates were use) for o,ti/i9ation ,ur,ose onl.

uantities of the /ajor ci-il wor( ite/s were /anuall calculate) fro/ the laouts ,re,are) for each o,tion. The weight of the gates an) trash rac(s were )eri-e) fro/ stan)ar) for/ulae.Li(ewise the cost of the electro/echanical e>ui,/ent an) the transfor/ers were calculate)

base) on the ,re-ailing international cost. Cost of trans/ission line an) sub%station is base) on

the ,re-ailing /ar(et ,rice ,resente) in Annex C.Annex C.

Details of the unit rates of ci-il wor( ite/s an) h)raulic steel structures are gi-en in Annex C.Su//ar of the unit rates of ci-il wor(s are su//ari9e) in Table ;%1*.

Tale 6 "nit Rates o7 Ma&or Ci*il 9or/ :tems

te/ $nit "ate in $S N

#-erbur)en xca-ation

4ar) "oc( xca-ationSteel "einforce/entSteel "einforce/ent for un)ergroun)structure

/*

/*

/*

/*

*

1*1001<0





For/wor( For/wor( for tunnelSteel "ibs

Steel Liner Concrete wor(sConcrete lining on roof an) walln-ert ConcreteShotcrete"oc( boltarth bac(fillTunnel exca-ationSurgetan( roc( exca-ation&ranular 'ac( filling

/2

/2

ton

ton/*

/*

/*

/*

//*

/*

/*

/*

121

1;00

*00101;0120*00

0<0;

uantities of the ci-il wor( ite/s of the in)i-i)ual structures an) res,ecti-e costs weight of theh)raulic steel structures an) the res,ecti-e costs an) the cost of the electro/echanicale>ui,/ent are gi-en in Annex C. #n these )irect costs following ,hsical contingencies wereuse). Table ;%*+ shows the su//ar of the total ,roject cost of )ifferent o,tions.

Physi%al %ontin#en%ies used3

• Surface Ci-il Structures 1O

• $n)ergroun) Ci-il Structures 1O

• 4)raulic Steel Structures O• lectro/echanical >ui,/ent O

• Trans/ission line O

Mis%ellaneous :tems3

• Cost of engineering a)/inistration an) construction su,er-ision assu/e) as ;O of the total

)irect cost.• n-iron/ental an) /itigation cost as *O of the total )irect cost.

• #wnerHs cost as *O of the total cost

Tale 65 !ummary o7 Cost 7or 8i77erent Options

!erial

No

:nstalled Capa%ity <M9= ?6 ?0 54 55

8es%ription Total Cost "!

1 Preli/inar x,enses :2;;100 <*:00 1:*00 120200

2 Access "oa)s an) 'ri)ge 2*00000 2*00000 2*00000 2*00000* 8eir I S,illwa +;<0< +;<0< +;<0< +;<0<

+ 'ox Cul-ert 0:2<: 0:2<: 0:2<: 0:2<:

nta(e I nta(e Channel ::<;: ::1 :*; ;201





A,,roach Canal 12+2 2:: 2+0

: Desan)er I )ownstrea/ canal +*+0;0 *0<;1 *11;;; 21;**+

; Su/, 200 22+*; 10;0: <<*;

< 4ea)raceTunnel 10**2<+ <**+:++ <011<:; ;:21;10 A)it Tunnel ;;12; ;;12; ;;12; ;;12;

11 Surge Tan( ::*0< :*<0; 2<<*; 1:1<

12 Dro, Shaft I Penstoc( ;;<11+ ;1;0 ;10:2; ;0<:*

1* Powerhouse *:;:;*0 **::< *12*21; 2<:2<2*

1+ Tailrace Pon) an) Canal an) switchar) 1*:1; 12:::< 11<;0 11;:

1 &ates 5al-es I Steel liner *1:*:0 *0:;;0 2<<0+0 2<;<0

1 Turbines &enerators I Accessories 2*200000 20000000 1;;00000 1:00000

1: Trans/ission Substations I Switchar) 2+0000 2+0000 2+0000 2+0000

T#TAL B'ase Cost :22+;+< 02+*+ +:<;*00 +1;<

ngineering 7anage/ent B;O of base +::<;; +0+<<:1 *;*;+0 *<2;

"esettle/ent an) n-iron/ent *O 1:1:+ 11;:*< 1+*<+<0 1*;+::

#wners cost *O 1:1:+ 11;:*< 1+*<+<0 1*;+::

Contingencies1O of Ci-il wor(s I Preli/inar

8or(sB1 %2 1+*;21 11<<0 111;< 111*0*0

1O of un)ergroun) wor( B *% 1+ 2:<*20: 2*:10; 2+1+20 2*2<02O of lectro/echanical an)

Trans/ission B1 % 1: 1+0:< 12;;++ 1221*2 1112;

Total Contingencies ;21<0 02200: +:+*;: +0121

&"A!D T#TAL :0<1;1; 2:*+0<0 <+012 :221<;"#$!DD &"A!D T#TAL :0<1<000 2:*+000 <+000 :222000

nstalle) Ca,acit B(8 ;000 0000 +:000 ++000

Cost ? (8 122* 12 12 1*01

6+6 Finan%ial 'nalysis

There are )ifferent /o)es of financing a h)ro,ower ,roject. 7ost of the ,rojects )e-elo,e) b !e,al lectricit Authorit B!A are finance) through the subsi)iar loan agree/ent with

&o-ern/ent of !e,al B&o! using )e-elo,/ent loan or foreign grants. The other /o)e of financing is through the ,ri-ate sector b in-ol-ing financing institutions. n this /o)e certain ,ortions of the cost are finance) through the e>uit an) re/aining ,ortions are finance) fro/ ban( loans. Foreign financing institutions are in-ol-e) for ,rojects of consi)erable si9e where aslocal institutions are in-ol-e) for s/all ,rojects. This ,roject is assu/e) to be finance) b the

,ri-ate sector b /obili9ing fun)s fro/ local financing institutions. 4ence the entire cost isesti/ate) in the local currenc. 4owe-er the cost corres,on)ing to electro/echanicale>ui,/ents inclu)ing -al-es an) h)raulic structures are esti/ate) in $S N an) is con-erte) tolocal currenc at the a,,ro,riate exchange rate.

Following are the basic assu/,tions /a)e for esti/ating financial cost

• 'ase ear for the cost an) benefit is 3anuar 2011.• Construction ,erio) is + ears. 4ence the Construction cost are )isburse) in four ears

• Co//ercial o,eration )ate is assu/e) to be 3anuar 1 201:.





• scalation rate on the local currenc is assu/e) to be O

• xchange rate for 1 $S N is :.00.

• Custo/ of 1.0O is assu/e) to be a,,licable on the electro/echanical an) trans/ission linecosts.

• Local taxes of 1.O are assu/e) to be a,,licable on entire ,roject co/,onents exce,t on the

electro/echanical trans/ission line ,roject engineering co/,ensation I /itigation an)ownerHs costs.

• 5alue) a))e) taxes of 1*.0O are assu/e) to be a,,licable on entire ,roject co/,onents exce,t

on the electro/echanical trans/ission line co/,ensation I /itigation an) ownerHs costs.

• )ebt e>uit ratio is :0*0

• ntire loan will be in local currenc.

• stablish/ent fee ,aable to co//ercial ban( is 0.0O on total )ebt co//it/ent at the ti/e of signing.

• Co//it/ent fee ,aable to co//ercial ban( is 0.0O ,er annu/ on unuse) )ebt )uring

construction ,erio).

• interest on loan are assu/e) to be 10.0O ,er annu/ an) the interest )uring construction are

ca,itali9e)

Detail brea()own of the total financial cost of the )ifferent o,tions consi)ere) for the )esign)ischarge o,ti/i9ation are ,resente) in Table !o. 1.

Tale 6? !ummary o7 Total Finan%ial Cost <Million Rs+=

!+

No+

:tems Cost 7or Rated 8is%har#e <%ume%s=

16+04 1?+.1 15+54 1+41

1. 'ase Cost as of 6ear 2011 +;<2.:* +*2;.+1 +102. *<+.2. Phsical Contingenc +2.1 *:. *.; *+.0<+ Total Cost as o7 Aear 2011 ?,16+6- 5,40?+0. 5,5?-+1 5,2-1+.?

+. Taxes an) Duties +<.2: +0;.1 *;:.+* *::.1?+ Total Finan%ial Cost as o7 Aear 2011 ?,446+1. ?,11+.4 5,65.+?. 5,..6+60

. Price Contingenc 111+.; <;.<2 <*+.01 ;<;.1:. Loan Processing Fees ;;.< :;.+ :+.*2 :1.+:;. nterest During Construction <2<.+ ;2*.* :;0.<1 :+.+1-+ Total Finan%ial Cost at the end o7

Constru%tion 4,-11+04 4,001+51 .,.?+60 .,-2+65

n or)er to co/,are the )ifferent o,tions on the basis of internal rate of return the ,resent -alueof the costs an) benefits of all the o,tions were )eter/ine) to the first ear of construction.





'enefit an) cost strea/s of each ca,acit o,tion for all the cases are as /entione) in Table !o.11 an) Table !o. 1+ res,ecti-el. The analsis was carrie) out for following two o,tions

Option H ' n this o,tion the entire energ is assu/e) to be sol) at the ,oste) rate of "s. :.00 ,er (8h for )r season an) "s. +.0 ,er (8h for wet season. Financial rate of return for )ifferent )esign )ischarges were esti/ate) in this o,tion.

Option H n this o,tion the ex,ecte) return on e>uit is assu/e) to be 1O. The re>uire)a-erage tariffs for )ifferent )esign )ischarges were esti/ate) in this o,tion.

The financial analses were base) on the following assu/,tions

• cono/ic life of the ,roject is * ears after co//ercial o,eration

•

Annual 'enefit starts fro/ the first ear of co//ercial o,eration• Annual cost of o,eration an) /aintenance is ta(en as 1.O of the ,roject cost an) )isburse/ent

of this starts fro/ fifth ear.

• Discount rate of 10O is use) to esti/ate benefit cost ratio

• A-erage energ cost is base) on 3anuar 2011 ,rice le-el an) is escalate) annuall at the rate of

*O ,er annu/ for first 10 ears of o,eration.

• x,ecte) return on e>uit is not less than 1O while esti/ating re>uire) energ rate.

• nterest on loan )uring o,eration is assu/e) to be 10.0O ,er annu/ an) the loan along with the

interest will be re,ai) in e>ual install/ents >uarterl.

• Loan )uration for co//ercial loan is 1 ears after the ear of co//ercial o,eration.

• Di/inishing balance /etho) with annual )e,reciation at the rate of +O ,er annu/ is a)o,te).

• Annual o,eration an) /aintenance cost is assu/e) to be 1O of the total construction cost an) is

escalate) at the rate of O.

• Annual insurance cost is 1.0O of the construction cost an) is escalate) at the rate of O.

• 'onus an) welfare fun) of 2O of net ,rofit annuall.

• "unner re,lace/ent cost is assu/e) to be 10O of the electro/echanical cost an) is assu/e) to

be re,lace) once in ten ears.• "oalt on installe) ca,acit is "s. 10 ,er (8 ,er annu/ for first 1 ears an) "s. 1200 ,er

(8 ,er annu/ then after.

• Ca,acit roalt will be escalate) at the rate of O ,er annu/ assu/ing 2001 as base ear.

• "oalt on re-enue is 1.;O on total re-enue for first 1 ears an) 10O on total re-enue then

after.

• cor,orate tax is 20O with no tax holi)a.

• ntire energ is assu/e) to be use) in )o/estic /ar(et.

6+- 'nalysis and Results





The )etails of the analsis are ,resente) in A,,en)ix . The su//ar of the results of thefinancial analsis for all cases of )ifferent ca,acit o,tions are shown in Table ;%1 an)A,,en)ix . The result of the analsis is ,resente) in Figure ;%1.

Tale 6. !ummary o7 the Result

!+

No

+

Rated 8is%har#e

<%ume%s=

:nstalled

Capa%ity <M9=

Finan%ial

Cost

<Million Rs+=

Option '

Return on

)Guity

<D=

Option

Tari77

as o7 2014

<Rs+;/9h=

1. 1;.0: ;.0 :<11.0: 11.01 .212. 1.1 0.0 :001.+1 1+.: +.<+*. 1+.+: +:.0 *0.: 1.0 +.<2+. 1*.:1 ++.0 *.;0 1.2; +.<0

t is seen that if the energ is assu/e) to be sol) at the ,oste) rate of "s. :.00 ,er (8h for )rseason an) "s. +.0 ,er (8h for wet season the return on e>uit of the ,roject is between11.01O to 1.2;O. Si/ilarl if the ex,ecte) return on e>uit is assu/e) to be 1O the a-eragetariff of the energ as of the ear 201: will be between "s. +.<0 ,er (8h to "s. .21 ,er (8h.





Fi#ure 61- Optimiation o7 8esi#n 8is%har#e

1$

1

4.$$

.$$

".$$

1$.$$

12.$$

14.$$

1.$$

OptimiCation o7 8esi#n 8is%har#e"pper Rahu#hat $ydroele%tri% Pro&e%t

eturn on E)uity 7D8 Average Energy ate 7(.:8

8esi#n 8is%har#e <%ume%s= L

Return on )Guity <D= ; '*era#e )ner#y Rate <Rs+; /9h= L

6+10 Con%lusion and Re%ommendation

The results of the o,ti/i9ation stu) are shown in Table 1 an) Figure 1. The results of theo,ti/i9ation stu) ha-e been base) on two scenarios. #ne has been base) on the fixe) ,oste)PPA rates b !A for ,rojects with an installe) ca,acit of below 2 78. The stu) on this

basis uses the fixe) rates of !"s :.00 an) !"s +.00 for the energ ,ro)uce) )uring the )r an)wet seasons res,ecti-el an) calculates the resulting return on e>uit. The secon) scenario





calculates the re>uire) /ini/u/ tariff rates for the energ generate) for the ,roject to iel) a/ini/u/ return on e>uit of 1 O.

Co/,arison of -arious alternati-e ca,acit o,tions as ,resente) in Table ;%* an) Figure ;%1shows that the o,ti/u/ )esign )ischarge lies between 1*.: cu/ecs an) 1. cu/ecs. As all theo,tions consi)ere) for the o,ti/i9ation stu) for the $,,er "ahughat 4)roelectric Project are/ore than 2 78 the o,ti/i9ation scenario base) on the return on e>uit on the basis of the

,oste) fixe) PPA rate is less a,,licable. 4ence the o,ti/i9ation scenario base) on the /ini/u/tariff rate for a fixe) return of e>uit of 1O is /ore reliable in this case. #n the base of thesha,e of the abo-e cur-e of tariff rate o,ti/u/ )esign )ischarge is esti/ate) to be 1.2 cu/ecs.This -alue is slightl less than the +0O )e,en)able flow. This woul) corres,on) to the installe)ca,acit of about +< 78. The o,ti/i9ation stu) therefore reco//en)s the ,roject to be)esigne) for the )esign )ischarge of 1.2 cu/ecs. The feasibilit )esign of the ,roject thus will

be )one for this )ischarge.




Upper Rahughat Hydroelectric Project Project !escription and !esign

-+0 PRO@)CT 8)!CR:PT:ON 'N8 8)!:>N

-+1 >eneral

The "ahughat =hola is one of the /ajor tributaries of =ali &an)a(i "i-er an) =ali &an)a(i"i-er is again one of the /ajor ri-ers of the Sa,ta &an)a(i 'asin. The "ahughat 'asin islocate) in between latitu)es 2;o 22 an) 2;o +2 ! an) longitu)es ;*o * an) ;*o 2: an) liesin 7ag)i District of 8estern De-elo,/ent "egion.

The ,roject site ,ro,ose) for the )e-elo,/ent of $,,er "ahughat 4)roelectric Project is bestowe) with a high hea) /o)erate )ischarge an) /o)erate geological con)itions. This ,roject is locate) i//e)iatel u,strea/ of the h)ro,ower ,roject being )e-elo,e) b !e,allectricit Authorit. !A has alrea) initiate) the i/,le/entation of this ,roject. A,art fro/these two ,rojects another h)ro,ower ,roject is also being stu)ies along this stretch of "ahughat "i-er an) it is locate) i//e)iatel u,strea/ of $,,er "ahughat 4)roelectricProject. This is "ahughat 7angale 4)ro,ower Project an) it is also license) to an PP. The

hea)wor( of this ,roject has been ,ro,ose) to be locate) at a ,lace) calle) Dhar an) the ,owerhouse has been ,ro,ose) on the right ban( of 'agar =hola a tributar of "ahughat=hola about 10 / u,strea/ fro/ the confluence of "ahughat "i-er an) 'agar =hola. This isalso the location for the hea)wor(s of $,,er "ahughat 4)roelectric Project. t can be seenthat $,,er "ahughat 4)roelectric Project is situate) in between two h)ro,ower ,rojects"ahughat 7angale 4)ro,ower Project on the u,strea/ si)e an) !A "ahughat 4)ro,ower

,roject on the )ownstrea/ si)e. Due to the -irtue of its location this ,roject is thus ,ro,ose) to be )e-elo,e) as a casca)e )e-elo,/ent to "ahughat 7angale 4)ro,ower Project.

-+2 Pro&e%t Con7i#uration

$,,er "ahughat 4)roelectric Project falls in the lesser than 100 78 categor un)er thegui)elines set forth b D#D. The general )esign ,rinci,les for the ,roject ha-e therefore beencarrie) out accor)ing to the gui)eline for this categor.

The ,roject structures ha-e been )esigne) accor)ing to the to,ogra,hical con)itions of the sitean) where-er ,ossible /easures ha-e been ta(en to /ini/i9e the cost. Since this ,roject is

being )e-elo,e) as a casca)e )e-elo,/ent the location of the hea)wor(s has been chosen sothat it co/,lies with location of the other structures es,eciall the location of the ,ower houseof "ahughat 7angale 4)ro,ower Project. The laout of the hea)wor(s of this ,roject has also

been influence) b the ,ro,osal to ,ro)uce ,ower fro/ 'agar =hola a tributar of "ahughat

=hola. The laout of the con-eance sste/ has to a great extent been )ictate) b theto,ogra,hical an) geological con)itions. The o-erall laout of the ,roject is shown in Dwg. !o.$"%PL%01.

Tundi Power Company 1 %ea(ii,ity &tudy

Chapter Nine

PRO@)CT 8)!CR:PT:ON 'N8 8)!:>N




-+2+1 >eneral 'rran#ement o7 the Pro&e%t Components

$,,er "ahughat =hola 4)roelectric Project with an installe) ca,acit of +;. 78 has its ,roject co/,onents locate) along the left ban( of "ahughat =hola. The ,roject basicallconsists of the hea)wor(s co/,lex with its interconnection sste/ to "74P an) thearrange/ent for the ,ro)uction of ,ower fro/ 'agar =hola locate) a,,roxi/atel 10 /u,strea/ fro/ the confluence of 'agar =hola an) "ahughat =hola a hea)race tunnel a surgetan( a surface ? un)ergroun) ,enstoc( a ,owerhouse an) a tailrace.

As /entione) earlier since this ,roject is being )e-elo,e) as a casca)e )e-elo,/et of "74Pthe two ,rojects are connecte) b /eans of an interconnection structure consisting of a cut an)co-er box cul-ert that ,asses beneath an) across 'agar =hola. The u,strea/ en) of this

interconnection structure is the tailrace of "74P ,owerhouse while at the )ownstrea/ en) itis connecte) to the collection su/, locate) a)jacent to the inta(e ,ortal of the hea)race tunnelof $"4P. 8hile this interconnection sste/ co/,rises of one ,art of the hea)wor(s structurethe basic ,roject co/,onents for the inta(e of a))itional )ischarge fro/ 'agar =hola alsoco/,rises as an i/,ortant ,art of the hea)wor(s co/,lex.

The arrange/ents /a)e for the extraction of the )esign )ischarge fro/ 'agar =hola basicallconsists of a weir inclu)ing an un)ersluice a gra-el ejector an) an e/ergenc s,illwa an) a)esan)er with a foreba at its )ownstrea/ en). Pro-ision has also been /a)e to ,ro)uce ,ower locall b /eans of intro)ucing a ,owerhouse with two units an) a ,air of twin surface

,enstoc(s connecte) to the foreba. The tailrace fro/ this ,owerhouse is connecte) to the

collection su/, locate) a)jacent to the inta(e ,ortal of the hea)race tunnel of $"4P.

n general the ,roject co/,onents ha-e been )i-i)e) broa)l as follows.

The weir the un)ersluice an) the e/ergenc s,illwa structure The )esan)er the foreba an) flushing structure The twin surface ,enstoc( for 'agar =hola Powerhouse The surface ,owerhouse for generation of ,ower fro/ 'agar =hola locall The tailrace connecting canal between the ,owerhouse an) the collection su/, The cut an) co-er box cul-ert

The collection su/, an) the ,ortal of the hea)race tunnel The hea)race tunnel The surge tan( The surface ? un)ergroun) ,enstoc( The surface ,owerhouse for $"4P The tailrace outlet

The general arrange/ent of the ,roject co/,onents are shown in Drawing !o. $"%48%01 an)$"%P4%01. Detail calculation of )esign of h)raulic structures an) o,ti/i9ation of tunnel an)

,enstoc( )ia/eters an) etc are shown in Annex D.





-+2+1+1 $eadwor/s >eneral 'rran#ement

The hea)wor(s site is locate) a,,roxi/atel 10 / fro/ the confluence of "ahughat an) 'agar

=holas. The to,ogra,h of the (hola ban(s in this area is relati-el flat with /o)erateexca-ation re>uire/ents. The hea)wor(s arrange/ent at 'agar =hola has been arrange) to ta(einto consi)eration the following factors

• Safe ,assage of the 1 in 100 ear floo) as ,er the re>uire/ents set forth in the

D#D gui)elines.

• A)e>uate flushing ,ro-isions through the un)ersluice.

• Controlle) flow to safeguar) the con-eance fro/ ingress of flow )uring the high

flow ,erio)s.• Pre-ention of entr of gra-el an) coarse be) /aterial into the con-eance.

The hea)wor(s co/,rises of a 20 / wi)e o-erflow weir )esigne) to ,ass the 1 in 100 ear )esign floo) at an ele-ation of L 1:0.;0 /asl. The right ban( is ,rotecte) b a 2 /eter thic( abut/ent wall raise) u, to an ele-ation of L 1:1.* /asl.

The weir has been ,ro-i)e) in such a wa that the original con)itions of the flow ,re-ail in thearea as /uch as ,ossible. A 1.0 / wi)e concrete gui)e wall has been ,ro-i)e) along the left

ban( of the o-erflow weir to gui)e the )esign floo) o-er the ogee sha,e) weir. The gui)e wall

will also hel, in gui)ing the low flows towar)s the inta(e area.

Details of the hea)wor( at 'agar =hola are shown in )rawings Dwg. !o. $"%48%01 to Dwg. !o. $"%48%0.

-+2+1+2 O*er7low 9eir

A 20 / wi)e b a,,roxi/atel . / high o-erflow weir has been ,ro-i)e) to gui)e the )esignflow into the inta(e an) also to ,ass the )esign floo) )uring the ti/es of high floo)s. The sha,eof the weir has been ,ro-i)e) to confor/ to an ogee sha,e. This ungate) o-erflow weir has

been locate) in the /ain section of the ri-er so as to /aintain the original waterwa of the ri-er to the extent ,ossible. The surcharge reaches a le-el of L 1:0.;0 /asl )uring ti/es of highfloo) while the crest of the s,illwa has been fixe) at an ele-ation of L 1;.00.

The o-erflow weir will consist of a concrete gra-it o-erflow section along the /ajor ,art of itsaxis an) an un)ersluice on the left ban( se,arate) b a 1.0 / wi)e gui)e wall. The si9ing of the free o-erflow weir an) the un)ersluice is -er /uch influence) b ,hsicalconstraints relate) to the abilit to ,ass floo) flows ri-er gra)ient at the weir site an) thestabilit of the section.

Due to the ri-er gra)ient an) the lac( of storage -olu/e at the weir site an uncontrolle) ogeeo-erflow section has been ,ro,ose) throughout the length of the )i-ersion weir.





'ase) on the arrange/ent ,ro-i)e) at the hea)wor(s the le-el of the crest of the inta(e has been set at an ele-ation of L 1.0 /asl while the crest ele-ation of the free o-erflow weir has been fixe) at L 1;.00 /asl.

Due to the nature of the ri-er in the hea)wor(s area it has been en-isage) that as far as ,ossible the original flow ,rofiles will ,re-ail. The ogee sha,e) s,illwa weir is foun)e) onallu-ial )e,osit an) has been )esigne) accor)ingl. t has an a,,roxi/atel 1 / long 72concrete )own strea/ a,ron with a concrete cut off structure which is about 2 / )ee,. Theu,strea/ concrete a,ron which is < /eter long has been ,ro-i)e) with a 2 / )ee, concrete cutoff. Stabilit analsis of the o-erflow weir has been carrie) out to chec( the safet of thestructure fro/ sli)ing an) o-erturning. The exit gra)ient has been chec(e) to safe guar) thestructure against u,lift. n or)er to ,rotect the outer surface of the s,illwa the entire s,illwa

surface u, to the )ownstrea/ a,ron will ha-e a har) stone ,itching surface.

The uncontrolle) s,illwa is )esigne) to ,ass the 1100 ears return ,erio) floo) e>ual to 2*1/*?sec.

Abut/ents on either si)e of the =hola an) the )ec( le-els ha-e been ,ro-i)e) abo-e the floo)water le-el corres,on)ing to the 1100 ears floo).

The sha,e of the o-erflow crest an) the ca,acit of the s,illwa ha-e been )esigne) inaccor)ance with the reco//en)ations of the $nite) States 'ureau of "ecla/ation. t isassu/e) that the u,strea/ ,ortion of the weir will be gra)uall fille) u, with se)i/ent )uringits o,eration in the subse>uent ears. An) hence it is en-isage) that the be) le-el at the ,art of the ri-er i//e)iatel u,strea/ of the s,illwa will ulti/atel be fixe) at L 1;.00 /asl.

The )i-ersion structure consists of a 1.0 / wi)e gui)e wall which se,arates the un)ersluicefro/ the o-erflow weir. This gui)e wall starts fro/ the beginning of the inta(e structure at theu,strea/ si)e an) en)s at the slo,ing glacis of the s,illwa at the )ownstrea/ en). The to,ele-ation of the gui)e wall is L 1:1.*. /asl.

The to, le-el of the abut/ent walls on either si)e of the weir an) the )ec( abo-e the un)er%sluice is locate) at an ele-ation of L 1:1.*0 /asl which is abo-e the high floo) le-el

corres,on)ing to the 100 ears return ,erio) floo).The o-erflow weir occu,ies /ost of the length of the )i-ersion structure an) it is . / highwhen /easure) fro/ the botto/ of the foun)ation. The weir will consist of a soli) reinforce)concrete structure foun)e) a,,ro,riatel 2 / below the original ri-er be) le-el to ensure itsstructural safet against sli)ing as well as o-erturining. The s,illwa will ,ass the )esign floo)of 2*1 /*?s at an ele-ation of l 1:0.;0 /asl. This gi-es a 0.0 / freeboar) to the abut/entan) )ec( le-el.

-+2+1+ "nderslui%e

The un)ersluice in-ert le-el has been fixe) at L 1*.0 /asl. The wi)th of the un)ersluice ba will be * / while its height will be 2.1 /. These o,enings will be create) b ,ro-i)ing a breast wall abo-e the o,enings. Sto, log gui)es will be ,ro-i)e) at the u,strea/ si)e of the breast wall to allow /aintenance of the un)ersluice gate an) e/be))e) /echanical ,arts. The

Tundi Power Company ! %ea(ii,ity &tudy




)ownstrea/ channel be) slo,e of the un)ersluice is stee, to facilitate flushing through theun)ersluice. The un)ersluice is )esigne) to ,ass the 12 ears floo) e>ui-alent to +;.< / *?sec.This flow corres,on)s to the annual floo).

-+2+1+5 :nta/e

The /ain ,ower inta(e has been locate) i//e)iatel u,strea/ an) a)jacent to the un)ersluiceto facilitate the safe with)rawal of the turbine flow of *.2 / *?sec at an ele-ation of L 1;.00/asl. The inta(e has been ,ro-i)e) with a narrow weir the crest le-el of which has been (e,tat L 1.00 / which is 2. /eter higher than the in-ert le-el of the un)ersluice. This woul)

,re-ent the intrusion of the be) loa) into the ,ower inta(e )uring floo). The inta(e )ec( has been )esigne) for the high floo) le-el corres,on)ing to the 1100 ears floo).

The ,ower inta(e is locate) just u,strea/ fro/ the un)ersluice. The inta(e has been set at anangle of <0 )egrees to the weir axis to facilitate the flushing of the be) /aterial an) to ensure as/ooth flow into the inta(e. The orientation of the inta(e channel an) the inta(e has beenarrange) so that a fa-orable flow con)ition ,re-ails in the hea)wor(s. The )i/ension of theri-er inta(e o,ening has been selecte) to /aintain a -elocit of a,,roxi/atel 0. /?s throughthe net area of the trash rac(s at the )esign )ischarge at the o,erating le-el of L 1;.00 /aslat the hea)wor(. This arrange/ent is ex,ecte) to ensure the flow of the )esign )ischarge intothe inta(e e-en )uring ti/es of /ini/u/ flow an) will also ,re-ent the intrusion of be) loa)

into the inta(e fro/ the ri-er )uring floo). The trash rac( will be (e,t at an inclination of :o

with the hori9ontal in or)er to ,re-ent the intrusion of floating /aterial.

A gra-el tra, has been ,ro-i)e) )ownstrea/ of inta(e to exclu)e the larger ,articles of theinflowing se)i/ent. &ra-el will be extracte) an) flushe) into the "ahughat =hola with theoutlet gate an) the flusing channel ,ro,ose) on left si)e of the un)ersluice.

The in-ert le-el of the gra-el tra, locate) i//e)iatel )ownstrea/ of the ,ower inta(e has been fixe) at an ele-ation L 1+.00 /asl. A sluice o,ening is ,ro-i)e) between the gra-eltra, an) the )esan)ing basin. The o,ening is *. /eter wi)e an) 0.0 /eter high. The crestle-el of the sluice is fixe) at L 1.00 /asl which is one /eter higher than the botto/ le-elof gra-el tra,. This will ensure the ,re-ention of intrusion of gra-el into the )esna)ing basin.Sub/erge) flow is ensure) through the sluice o,ening b ,ro-i)ing a baffle just )ownstrea/ of the sluice gate in or)er to control the excess )ischarge e-en at high floo) le-el. Dischargethrough the sluice at the nor/al o,erating le-el of L 1<;.00 /asl at hea) wor( is esti/ate)to be about *.* /*?sec if the water le-el at )esan)ing basin is L 1:.0 /asl. 4owe-er thewater le-el at )esan)ing basin will be slightl higher if the turbine flow at 'agar =hola is *.2/*?sec. At high floo) le-el of L 1:0.;0 /asl at hea)wor( /axi/u/ flow through the sluiceis esti/ate) to be :.+1 /*?sec for the /axi/u/ water le-el of L 1;.1 /asl at )esan)ing

basin. $ncontrolle) s,illwa is ,ro-i)e) just )ownstrea/ of the sluice in or)er to control thewater le-el at )esan)ing basin. The crest length of the s,illwa is /eter an) the crest le-el is

fixe) at L 1:.0 /asl.

Tundi Power Company # %ea(ii,ity &tudy




The wor(ing ,latfor/ for the trash rac( cleaning /achine an) the hoist for the inta(e sto, logsas well as the sto,logs locate) at the orifice inta(e will be at L 1:1.*0 /asl. The )ec( le-elof the inta(e is abo-e the 4FL corres,on)ing to the 1100 ears floo).

-+2+1+? 8esandin# asin and Flushin# !tru%ture

n or)er to re)uce the erosion of the gui)e -anes an) runners of the Francis turbines an) ,eltonturbines b sus,en)e) se)i/ents a )esan)ing basin is re>uire). The )i/ensions of the

)esan)ing basin )e,en) on the characteristics of the ri-er the )esign )ischarge an) the ,articlesi9e to be re/o-e) which is t,icall 0.2 // for ,rojects on the 4i/alaan "i-ers. Thegeneral tren)s with recent stu)ies carrie) out on h)roelectric ,rojects in !e,al show that the)esan)ing basin in general is )esigne) to tra, <O of the 0.2 // )ia/eter ,articles entering

the basin fro/ the ri-er. Due to the si9e of the ,roject a single ba )esan)ing basin with a singlecha/ber has been ,ro-i)e). The )esan)ing basin has been )esigne) for a )ischarge of *.2/*?sec. The settling -elocit for the critical grain si9e is 0.02 /?sec. The wi)th of the singlecha/ber is .0 /. Li(ewise the )e,th of flow -aries fro/ *.0 / at the u,strea/ en) to *.: / atthe )ownstrea/ en).

The effecti-e length of the )esan)ing basin will be *.0 /. The basin will a ha-e flushingcon)uit with a botto/ wi)th of 1.0 / an) a trans-erse slo,e of 1 in 1 on both the si)es. Thelongitu)inal slo,e of the flushing channel will be 2O. The flushing con)uit will be ,lace) at theen) of the )esan)ing basin to ensure co/,lete flushing of the basin. A weir li(e structure is

,ro-i)e) at the en) of the )esan)ing basin. The crest le-el of this structure is fixe) at an

ele-ation of L 1.0 /asl. This structure will ,re-ent the intrusion of the se)i/ent collecte)in the )esan)ing basin to the )ownstrea/.

The nor/al water le-el in the )esan)ing basin will be /aintaine) at an ele-ation of L 1:.0/asl. The si)e walls of the basin will be exten)e) u, to L 1;.0 /asl. This will gi-e a 1.00/eter free boar) in the )esan)ing basin )uring nor/al flows. The flow into the )esan)ing basinwill be controlle) b the ,ro-ision of an orifice o,ening locate) in the inta(e channnel. Thiswill hel, to facilitate the control of flow into the )esan)er e-en )uring ti/es of floo).

At the lower en) the )esan)ing basin en)s at the flushing channel. The control gate to o,eratethe flushing con)uit is ,ro-i)e) at the )ownstrea/ en) of the con)uit just as it e/erges fro/

below the )esan)ing cha/ber. The flushing channel will be a,,roxi/atel 1. / wi)e an) 1 /high an) a,,roxi/atel 2 / long. nter/ittent flushing is ,ro,ose) in the )esan)ing basins.Flushing of the )esan)ing basin will be acco/,lishe) b using a hea) cutting ,rocess for whichit is essential to ha-e su,ercritical flow along the basin floor )uring the o,eration. To obtain there>uire) h)raulic con)ition the be) slo,e of the )esan)ing basin flushing con)uit an) theflushing channel are all (e,t at a /ini/u/ slo,e of of 2O. The flushing channel will flush these)i/ent la)en water bac( into 'agar =hola.

Flushin# Operation

The flushing o,eration will be initiate) with the closing of the )esan)er outlet gates. Then theflushing gates will be full o,ene) an) the water le-el in the basin will be allowe) to )ro, untilhea) cutting ,rocess starts in the basin. The inta(e gate will be (e,t full o,en throughout theflushing ,rocess to allow a constant flow to continue the hea) cutting ,rocess. After re/o-al of





all the se)i/ent in the basin the flushing gate will be close) for the refilling of the )esan)ing basin. At the en) of the refilling ccle when the water le-el in the )esan)er ba is the sa/e asin the collection cha/ber the outlet gate is o,ene) un)er balance) con)itions.

-+2+1+. Foreay

The foreba acts as a regulating ,on)age to cushion the i/,act of su))en loa) rejection or loa)acce,tance. The foreba is also ,ro-i)e) to function as a balancing reser-oir in case of thesu))en )e/an) in the ,ressure con)uit. Due to the si9e of the ,roject the cha/ber locate) at

the )ownstrea/ en) of the )esan)er will act as the foreba for this ,roject. 8ater ha//ering isex,ecte) )uring the su))en closure of the /ain inlet -al-e at the ,owerhouse an) this forebacha/ber will act to cushion the effect.

2This foreba cha/ber will be locate) at the en) of the )esan)ing basin at the outsi)e ben) of the hillsi)e. The sha,e of the surface area of the foreba has been ,ro-i)e) to blen) in with theto,ogra,hical con)itions at this location. This cha/ber has a net length of 11.+ / an) has aheight of .20 /. The inlet to the twin surface ,enstoc( ,i,es will be ,ro-i)e) on the right ban( si)e of the foreba an) hence the le-el of the to, of this inlet has been fixe) such that asufficient )e,th will be /aintaine) to ta(e care of the -ortex consi)erations. The location for the inlet has been gui)e) b the to,ogra,h an) the location of the ,owerhouse.

-+2+1+4 Power >eneration at a#ar Khola

As /entione) earlier a surface ,owerhouse has been ,ro,ose) in the hea)wor(s area togenerate ,ower locall. This arrange/ent will consist of two surface ,enstoc(s )i-erting thewater fro/ the foreba )own to the ,owerhouse an) then )ischarging the flow into thecollection su/,.

Two ex,ose) surface ,enstoc( ,i,es ha-e been ,ro-i)e) fro/ the foreba )own to the ,owerhouse. The )ia/eter of the ,i,e has been o,ti/i9e) an) the whole stretch of the ,i,e has been )esigne) as a high ,ressure con-eance sste/. 'ase) on the o,ti/i9ation stu) the)ia/eter of the ,i,e has been fixe) at 1.2 /.





0.00

0.0

0.10

0.1

0.20

0.2

P5 of Loss P5 of Cost P5 of Total Loss

Finish 8iameter <m=

Present 9orth o7 oss <Million "! =

Fi#ure -20 Optimiation o7 !ur7a%e Pensto%/ 7or a#ar Khola Powerhouse

The surface ,enstoc( starts out fro/ the outlet at the foreba. The align/ent follows the)ownhill slo,e after e/erging fro/ the foreba outlet. The to,ogra,h is co/,arati-el gentleat this location.

ach of the surface ,enstoc( ,i,es will be su,,orte) on two anchor bloc(s. #ne anchor bloc( will be locate) at the u,strea/ en) while the other one will be locate) at the )ownstrea/ en)an) connecte) to the ,owerhouse. ach of the ,enstoc( will be ,ro-i)e) with an ex,ansion

joints locate) i//e)iatel )ownstrea/ of the u,,er anchor bloc(.

The ,ro,ose) surface ,owerhouse will also be locate) on the left ban( of 'agar =hola in the-icinit of the other structues. The ,owerhouse will acco//o)ate two hori9ontal axis FrancisTurbines an) generators each with a ca,acit of 12 =8 an) ancillar facilities for control an)

,rotection. The location of the ,owerhouse is such that it re>uires -er little exca-ation an)slo,e ,rotection wor(s.The unit si9e of 12 =8 is base) on a /ini/u/ of two nu/bers of units in the ,owerhouse sothat ,ower ,ro)uction can be continue) with higher efficiencies )uring the low flows. Althoughthe installation of onl one unit of *2+ =8 is ,ossible /aintenance re>uire/ents alsonecessitates the installation of two units.

The s,acing of the turbine?generator units is go-erne) b the si9e of the generator inclu)ingthe exciter s,ace re>uire) between the generator an) turbine enclosures. A unit s,acing of :.0 /has been ,ro-i)e) for the 'agar =hola Powerhouse. A hori9ontal turbine%generator align/enthas been a)o,te) as it ,ro-i)es eas access to the e>ui,/ent an) the ,owerhouse laout is





si/,le thereb econo/i9ing the costs. The turbine setting has been /aintaine) at an ele-ationof L 1.0 so as to ,rotect the ,owerhouse fro/ high floo)s.

The o-erall length of the ,owerhouse is go-erne) b the unit s,acing of turbine?generator an)the s,ace re>uire) for the erection ba. An o-erall length of 1; / has been ,ro-i)e) to cater tothese re>uire/ents. The control roo/ an) wor(sho,s are locate) towar)s the north east en) of the ,owerhouse. The wi)th of the ,owerhouse hall is go-erne) b the )ia/eter of the FrancisTurbine inclu)ing the s,ace re>uire/ents for ancillaries li(e the /ain inlet -al-es generator control ,anel etc. The wi)th of the /ain hall has been fixe) at ;.+0 /. The height of the

,owerhouse /ain hall is go-erne) b the -ertical )istance re>uire) for the trans,ortation of thegenerator stator height of gantr crane an) the height re>uire) for the roof. The o-erall heightof the ,owerhouse is thus esti/ate) to be 10. /.

The erection ba also lies on the northern en) of the /ain hall. The ,owerhouse acco//o)ates

a control roo/ an) a wor(sho, on its north eastern si)e. The ,enstoc(s fee) the )esign flowinto the turbines through butterfl -al-es on the eastern si)e of the ,owerhouse. The two )raft%tubes )ischarge into a single tailrace con)uit. This single tailrace con)uit )ischarges the flowfro/ the ,owerhouse through an outlet structure bac( into the collection cha/ber locate)a)jacent to the ,ortal of the hea)race tunnel for $"4P.

n -iew of the econo/ic re>uire/ents the generators an) turbines inclu)ing the erection ba aswell as the e>ui,/ent roo/s ha-e all been locate) at an ele-ation of L 1.00 /asl. Thecontrol roo/ will also be locate) on this sa/e floor so that it can ,ro-i)e a clear -iew of theo-erall ,owerhouse.

The ,owerhouse consists of one /ain floor at an ele-ation of L 1.00 /asl. The /ain floor

consists of the erection ba which acco//o)ates the turbine an) generator co/,onents )uringinitial an) consecuti-e erection of the units an) )uring future /aintenance ,erio)s. S,ace isalso ,ro-i)e) for -ehicular access asse/bl of the )raft tube liner turbine sta ring an) hea)co-er /ain shaft gui)e bearing an) rotor. This area ser-es as a la )own area for the runner.The wor(sho, will also be locate) at the erection ba le-el.

The tailrace for the 'agar =hola ,owerhouse consists of an a,,roxi/atel 2 / long o,en

canal ha-ing a si9e of 1 / in )e,th an) 2 / wi)th.This tailrace canal collects the )ischargefro/ the )raftubes an) con-es it into the collection su/, locate) at the inlet to the hea)racetunnel.

The o-erall laout of the arrange/ent for ,ower generation at 'agar =hola is shown inDrawing !o. $"%48%01 an) the section across the foreba ,enstoc( an) ,owerhouse isshown in Drawing !o. $"%'P4%01.

-+2+1+6 Cut and Co*er o( Cul*ert

A cut an) co-er box cul-ert section will )eli-er the )ischarge fro/ the ,owerhouse of "74P

to the collection cha/ber locate) on the left ban( of 'agar =hola. This cut an) co-er sectionwill ,ass fro/ beneath an) across 'agar =hola ri-er be). A,,ro,riate ,rotection will be ,ro-i)e) o-er the to, of the cut an) co-er section so that it will be ,rotecte) against the scour of the ri-er be) e-en at ti/es of high floo)s. The cut an) co-er section will be .0 / in length

Tundi Power Company 1! %ea(ii,ity &tudy




an) will ha-e a si9e of *.2 / b *.2 / an) will consist of reinforce) ce/ent concrete boxstructure. This cut an) co-er box cul-ert has been )esigne) as a ,ressure flow con)uit.

-+2+1+- Colle%tion Chamer

A collection cha/ber locate) on the left ban( of 'agar =hola i//e)iatel )ownstrea/ of the'agar =hola ,owerhouse will act as the interface in between the cut an) co-er box cul-ert an)the hea)race tunnel. This collection cha/ber will also collect the flow fro/ the 'agar =hola

,owerhouse as /entione) earlier. This collection su/, will be constructe) of reinforce)ce/ent concrete an) its length brea)th an) height will be 12.0 / b ;.0 / b 10.: /res,ecti-el.

-+2+1+10 $eadra%e Tunnel

The hea)race tunnel starts fro/ the )ownstrea/ en) of the collection su/, an) en)s at the botto/ of the surgetan(. The total length of the hea)race tunnel is a,,roxi/atel +;: /eters.The si9e of the hea)race tunnel was o,ti/i9e) as ,er the nor/al ,roce)ure in )eter/ining thesi9e of the tunnels of h)ro,ower ,rojects. A,art fro/ the basic assu/,tions the followingassu/,tions were also /a)e for the o,ti/i9ation of the hea)race tunnel

• The tunnel is full concrete line).

• The /axi/u/ -alue of /anningHs coefficient for concrete lining is 0.01+ where as the

/ini/u/ -alue is 0.01.

• The /ini/u/ thic(ness of the lining is 20 c/.

• Cost of )r season energ is 0.0< $SN ,e =8h whereas that of wet season energ is0.0$SN ,er =wh

The total length of the hea)race tunnel fro/ the inlet at the collection su/, u, to the ,ro,ose)location of the botto/ of the surge tan( is esti/ate) to be +;: /eters. The o,ti/u/ )ia/eter of the hea)race tunnel is esti/ate) to be *.+ /eters. The tunnel is horse shoe sha,e) on theoutsi)e while the inner section is circular. The result of the o,ti/i9ation stu) of the hea)racetunnel is shown in Figure !o. <%2. The exca-ate) )ia/eter of the tunnel -aries a,,roxi/atelfro/ *.< /eters for areas in stronger roc( t,es while it is +.10 in the wea( roc( 9one t,e.The in-ert le-el of the hea)race tunnel at the entrance is L 1+.*0 /asl an) the in-ert le-elof the hea)race tunnel at the location of the surge tan( is esti/ate) to be L 12.<+ /asl. Thea-erage slo,e in the hea)race tunnel is a,,roxi/atel 1 20. The longitu)inal ,rofile of thehea)race tunnel is ,resente) in the Drawing !os. $"%4"T%01 an) $"%4"T%02.

Tundi Power Company 1# %ea(ii,ity &tudy




0.00

20.00

+0.00

0.00

;0.00

100.00

120.00

P5 of Loss P5 of Cost P5 of T otal Loss

Finish 8iameter <m=

Present 9orth o7 oss <Million "! =

Fi#ure -21 Optimiation o7 the Conrete ined $eadra%e Tunnel

-+2+1+11 !ur#e Tan/

The si9ing of the surge tan( was )one b using the Tho/a relationshi, which consi)ers the ,ressure ,ara/eters of the ,ower tunnels. The surge tan( is ,lace) as far )ownstrea/ as ,ossible in or)er to /axi/i9e the effecti-e controlling in the high ,ressure section of tunnel.The location of the surge tan( is chosen in such a wa that the /axi/u/ ex,ecte) water le-el)uring u, surge is near to the original groun) le-el. The si9e of the surge tan( has been)eter/ine) to satisf the following con)itions

• The cross section of the surge tan( is not less than the Tho/a Cross Section area buthowe-er it shoul) be a ,ractical )ia/eter to facilitate construction.

•A)e>uate freeboar) shoul) be ,ro-i)e) abo-e an) below the /axi/u/ u,surge an)/ini/u/ )own surge le-els. This shoul) also ta(e into consi)eration the to,ogra,hicalfeatures of the area.

A /ini/u/ hea) loss in the hea)race tunnel was assu/e) to esti/ate the /axi/u/ u,surgewhereas a /axi/u/ hea) loss in the hea)race tunnel was assu/e) to esti/ate the /axi/u/)own surge. The )ia/eter of the surge tan( is fixe) in such a wa that the ratio of the frictionloss to the /axi/u/ surge neglecting friction is less than 0.; for the u,surge an) )own surgecalculations. 3aegerHs e>uation was use) to esti/ate the /axi/u/ u,surge an) Cala/e an)&a)enHs relationshi, was use) to esti/ate the /axi/u/ )own surge.

The oscillation of water le-el in the surge tan( )uring the u,surge an) )own surge wasesti/ate) using an arith/etical integration /etho). The basic assu/,tions for thesecalculations are as follows





• For u,surge full loa) rejection i.e. )ischarge at the turbines )ecreases fro/ 1.2/*?sec to 0 /*?sec an) the hea) loss in the tunnel is /ini/u/.

• For )own surge full loa) increase i.e. )ischarge at the turbines increases fro/ 0 /*?sec

to 1.2 /*?sec an) the hea) loss in the hea)race tunnel is /axi/u/ .• As there are two units installe) in this ,roject the scenario with a su))en consecuti-e

starting of the secon) unit i//e)iatel after the o,eration of the first unit was alsoexa/ine).

• Si/ilarl a su))en start of the one unit i//e)iatel after the full loa) rejection wasalso anal9e).

A,art fro/ the assu/,tions /a)e for the o,ti/i9ation of the hea)race tunnel the followingassu/,tions were also /a)e to fix the si9e of the surge tan(

• 7ini/u/ free boar) for the surge tan( shoul) at least be * /eter.• 7ini/u/ co-er for the surge tan( orifice shoul) at least be /eter.

'ase) on the results of the )esign a restricte) orifice surge tan( with a <.0 /eter internal)ia/eter will be ,ro-i)e) at the en) of the hea)race tunnel at a )istance of a,,roxi/atel +;:/eters fro/ the ,ortal face of the tunnel at the collection cha/ber. n or)er to ta(e intoconsi)eration the )na/ic ,ressure exerte) b the su))en loa) acce,tance an) rejection thesurge tan( has been ,lace) a,,roxi/atel 10 / u,strea/ of the -al-e cha/ber. The orifice)ia/eter is esti/ate) to be 2.0 / where as the )e,th of the orifice is esti/ate) to be 2 /. Thenor/al water le-el at the surge tan( is L 11.:2 /asl. The /axi/u/ water le-el in the surge

tan( is esti/ate) to reach L 1:.1 /asl at loa) rejection an) the /ini/u/ water le-el isesti/ate) to reach L 1*.2; /asl )uring /axi/u/ )own surge. The /axi/u/ )own surgele-el corres,on)s to the consecuti-e full loa) acce,tance fro/ the secon) unit i//e)iatelafter the full loa) acce,tance b the first unit.





0 200 400 600 800 1000 1200 1400

1530.00

1535.00

1540.00

1545.00

1550.00

1555.00

1560.00

1565.00

1570.00

Variation of Water Surface in Surge Tank with Time

Water Surf ace in Surge Tank

Time (seconds) ----->

Water Le vel at Surge Tank (m asl) ----->

Fi#ure -22 Full oad Re&e%tion

0 200 400 600 800 1000 1200 1400

1532.00

1534.00

1536.00

1538.00

1540.00

1542.00

1544.00

1546.00

Variation of Water Surface in Surge Tank with Time

Water Surf ace in Surge Tank

Time (seconds) ----->

Water Le vel at Surge Tank (m asl) ----->

Fi#ure -2 Full oad '%%eptan%e a7ter immediate the Full oad Re&e%tion <1 "nit=

The le-el of the to, o,ening of the surge tan( has been fixe) at L 1:0.1 /asl. The totalheight of the surge tan( fro/ the crown of the hea)race tunnel u,to the to, inclu)ing thefreeboar) is a,,roxi/atel *;.;: /eter. The in-ert le-el of the hea)race tunnel at the surge

tan( location is esti/ate) to be L 12.;; /asl. The surge tan( will ha-e a 20 c/ thic( shotcrete an) a 0. /eter thic( reinforce) concrete lining. The exca-ate) )ia/eter of the surgetan( is esti/ate) to be 10. /.





A gate -al-e cha/ber a,,roxi/atel 12 / in length with a butterfl -al-e will be ,lace) in between the surge tan( an) the hea)race tunnel outlet ,ortal. The ,ro-ision of this -al-e will

facilitate the e/,ting of the water in the surface ,enstoc( the incline) shaft an) the high ,ressure tunnel without ha-ing to e/,t the water in the surge tan(.

Details of the surge tan( are ,resente) in the Drawing !o. $"%ST%01.

-+2+1+12 !ur7a%e Pensto%/

An ex,ose) surface ,enstoc( ,i,e has been ,ro-i)e) fro/ the hea)race tunnel outlet ,ortal)own to the ,owerhouse. The total length of this surface ,enstoc( ,i,e is a,,roxi/atel **: /.The )ia/eter of the ,i,e has been o,ti/i9e) an) the whole stretch of the ,i,e has been)esigne) as a high ,ressure con-eance. The result of the o,ti/i9ation of the ,enstoc( )ia/eter

is shown in the Figure <%. 'ase) on the o,ti/i9ation stu) the )ia/eter the ,i,e has beenfixe) at 2.+ /. The thic(ness of the ,enstoc( ,i,es -aries fro/ ; // at the to, to 2+ // at theen). . Details of the steel t,e are shown in section <.2.*.2.





0.00

2.00

+.00

.00

;.00

10.00

12.00

P5 of Loss P5 of Cost P5 of Total Loss

Finish 8iameter <m=

Present 9orth o7 ,oss <Million "! K=

Fi#ure -25 Optimiation o7 the !ur7a%e Pensto%/

The surface ,enstoc( starts out fro/ the outlet ,ortal. The align/ent follows the )ownhill slo,eafter e/erging fro/ the outlet ,ortal. The o-erall align/ent follows the to,ogra,h with-ertical ben)s at locations.

The entire length of the surface ,enstoc( is su,,orte) on anchor bloc(s an) sa))le bloc(s. Theanchor bloc(s ha-e been a,,ro,riatel locate) at hori9ontal an) -ertical ben)s. x,ansion

joints shall be ,ro-i)e) at a,,ro,riate locations with res,ect to these anchor bloc(s. Thesurface ,enstoc( is connecte) to the un)ergroun) incline) )ro, shaft. The last anchor bloc( will

be the connection ,oint between the surface ,enstoc( an) incline) )ro, shaft.





!addle !upport

These are the reinforce) ce/ent concrete sa))le bloc(s unifor/l s,ace) at e-er / along

the length of the ,enstoc(. n general the s,acing of the sa))les for such t,e of )e-elo,/ent is(e,t at a )istance of + to : / )e,en)ing u,on the si9e an) t,e of ,enstoc( an) the to,ogra,hof the groun). The si9e of sa))les is about 1.0 / long x 1. / wi)e x 1.; / high. The sa))lesu,,ort is not a unifor/ rectangular bloc( % the height -aries fro/ 1 / to * / fro/ the stabilit

,oint of -iew.

The ,enstoc( rests clear off *0 c/ on the to, of the sa))les. "ing stiffeners are use) to hol) the ,enstoc( in ,osition. The stabilit of the sa))le bloc( at the groun) ,rofile ha-ing such slo,ean) )e,th of be)roc( is a critical issue. The sa))les cannot be foun)e) on be)roc( in all thelocations as the assu/e) roc(line along the ,enstoc( line falls at a )e,th of a,,roxi/atel * to

+ / fro/ the to, surface. 'ut re/o-ing the to,soil an) ,utting the foun)ation o-er it brings outrelati-el goo) footing con)ition for the sa))le su,,orts. So in /ost locations the are foun)e)on the inter/e)iate laer of san) an) cla.

'n%hor lo%/s

An anchor bloc( generall consists of a /ass of reinforce) concrete structure surroun)ing the ,enstoc(. Anchor bloc(s are ,ro-i)e) where there is a change in align/ent either -erticall or hori9ontall an) where there is a long tangent along the stretch. There are fi-e -ertical ben)salong the )ownhill slo,e. Li(ewise there are two hori9ontal ben)s at /anifol). The final ben)is locate) where it enters the groun) an) joins the incline) )ro, shaft. Altogether there are :anchor bloc( an) their )etails are as follows

Tale -4 8etails o7 'n%hor lo%/s

'n%hor

lo%/

No+

"pstream

pensto%/

len#th <m=

Verti%al

end 'n#le

$oriontal

end 'n#le

'n%hor lo%/ !ieRemar/s

en#th 9idth $ei#ht

1 .< 21 .1 *. .;:

2 ;< 0 .2 *. .:*

<0.: ** .+ *. :.;:

5 ::.* 1 .*: *. *.*;

? +. 21 +.< *. 2.

. 0 0 *< .** *. +.1

4ighPressuretunnel at

$?S

4 ;.; 0 *< +.+ 2.: *.1

The ,enstoc( ,asses through the anchor bloc(s. For goo) stabilit the anchor bloc(s arereco//en)e) to be foun)e) on be) roc(. 'ut in so/e cases when the be) roc( is locate) at a)e,th of + to / or /ore below the surface the )esire) con)ition for a goo) footing /a not





be a-ailable. 8hen the assu/e) bearing ca,acit for the inter/e)iate laer of soil is relati-ellow in the range of 20 tons? s> / or lower then in such cases the anchor bloc( is ,ro,ose) to

be tie) to the be)roc( with the hel, of tie ro)s )rille) to the be)roc( fro/ the base of the

anchor bloc(. This strengthens the anchorage between the be)roc( an) the anchor bloc( .

The longitu)inal ,rofile of the ,enstoc( is shown in Drawing $"%PS%1 to . Section is sown in)rawing $"%PS%02. Drawing $"%PS%0+ shows the )etails of anchor bloc(.

-++ :n%lined 8rop !ha7t and $i#h Pressure Tunnel

The incline) )ro, shaft an) the steel line) high ,ressure tunnel sections are circular in sha,e.The incline) shaft starts fro/ the en) of the surface ,enstoc( section an) is also circular in

section an) also has a finishe) )ia/eter of 2.+ /eters. The total length of the incline) shaft is22* / exclu)ing the length of the transition. ts angle of inclination of is 0 o )egrees to thehori9ontal. This incline) shaft is followe) b a 110 / long 2.+ / )ia/eter circular steel line)high ,ressure tunnel. The whole of the length of the surface as well as un)ergroun) ,enstoc( will be steel line). The steel lining of the incline) )ro,shaft an) the high ,ressure tunnel has

been )esigne) to resist the full loa) without transferring it to the surroun)ing be) roc(.

The o,ti/u/ finishe) )ia/eter of the steel line) tunnel is 2.+ /eters. The thic(ness of the steellining is 2+ to *2 // whereas that of the concrete lining is *0 c/ for the fro, shaft. The

shotcrete thic(ness is esti/ate) to be 10 //. The high ,ressure tunnel is horse shoe sha,e)on the outsi)e while the inner section is circular. The steel lining is *2 // in case of high ,ressure tunnel.

Mani7olds

7anifol)s will be ,ro-i)e) at the en) of the high ,ressure tunnel. This will fee) the )ischargeinto each turbine. Si9es of these /anifol)s were fixe) in such a wa that the -elocit of flowre/ains the sa/e as the -elocit in the high ,ressure steel line) tunnel. .

The ,enstoc( branches into two units near the ,owerhouse area in or)er to fee) the )ischargeinto two )ifferent turbines. This /anifol) is (e,t in the sa/e hori9ontal ,lane the centerline being at L 11:.0 /asl. The )ia/eter of each branch is 1.: / so that the -elocit is sa/ethroughout the length an) e>ual )i-ision of water is ,ossible. The total length of ,enstoc( in the/anifol) is 22.00 / each. The )istance between the two )istributors at the /anifol) is 1;.0 /.The thic(ness of the steel lining in this ,ortion is esti/ate) to be *2 //.

The longitu)inal ,rofile of the )ro,shaft an) high ,ressue tunnel is shown in Drawing $"%PS%1to . Section is sown in )rawing $"%PS%0*.





-+2+1+1 Powerhouse

The ,ro,ose) surface ,owerhouse for $,,er "ahughat =hola 4)roelectric Project is locate)

on the left ban( of "ahughat =hola in the -icinit of Dagna/ -illage. The ,owerhouse site issituate) in an ex,ose) area along the hillsi)e. The area co/,rises of thic( allu-ial )e,osits onthe surface. The ,owerhouse will be foun)e) on be)roc( with a rather stee, hill slo,e. The

,owerhouse will acco//o)ate two -ertical axis ,elton turbines an) generators each with aca,acit of +;.0 78 an) ancillar facilities for control an) ,rotection. The location of the

,owerhouse is such that it re>uires a fairl large >uantit of o-erbur)en an) roc( exca-ationan) slo,e ,rotection wor(s. The geolog of the area in)icates that the be)roc( )i,s into thehillsi)e gi-ing the area a relati-el stable status.

The o-erall laout of the ,owerhouse co/,lex inclu)ing the high ,ressure tunnel an) tailrace is ,resente) in Drawing !o. $"%P4%01.

The unit si9e of 2+.2 78 is base) on two nu/bers of units in the ,owerhouse so that ,ower ,ro)uction can be continue) with higher efficiencies )uring low flows.

The s,acing of the turbine?generator units is go-erne) b the si9e of the generator inclu)ingthe exciter s,ace re>uire) between the generator an) turbine enclosures. A unit s,acing of 1; /has been ,ro-i)e) for the $,,er "ahughat =hola 4P ,owerhouse. A -ertical turbine%generator align/ent has been a)o,te) as this t,e of arrange/ent is /ore a,,ro,riate for bigger units.The turbine setting has been /aintaine) at an ele-ation so as to ,rotect the ,owerhouse fro/

high floo)s.

The o-erall length of the ,owerhouse is go-erne) b the unit s,acing of the turbine an) thegenerator an) the s,ace re>uire) for the erection ba. An o-erall length of +* / has been

,ro-i)e) to cater to these re>uire/ents. The control roo/ an) wor(sho,s are locate) on theu,strea/ en) of the ,owerhouse. The wi)th of the ,owerhouse hall is go-erne) b the )ia/eter of the ,elton turbine inclu)ing the s,ace re>uire/ents for ancillaries li(e the /ain inlet -al-esgenerator control ,anel etc. The wi)th of the /ain hall has been fixe) at 1 /. The height of the

,owerhouse /ain hall is go-erne) b the -ertical )istance re>uire) for the trans,ortation of thegenerator stator height of gantr crane an) the height re>uire) for the roof. The o-erall heightof the ,owerhouse is thus esti/ate) to be 22 / when /easure) fro/ the in-ert le-el of thetailrace u, to the botto/ of the crane rail.

The erection ba also lies on the southern en) of the /ain hall. The ,owerhouse acco//o)atesa control roo/ an) a wor(sho, on its u,strea/ si)e. The ,enstoc(s fee) the )esign flow intothe turbines through butterfl -al-es along the eastern si)e of the ,owerhouse. The )raft%tubes)ischarge into a tailrace ,on) that )ischarges flow )irectl into "ahughat =hola. Thisarrange/ent has been a)o,te) to ta(e into consi)eration the to,ogra,h of the area.

n -iew of the econo/ic re>uire/ents the /ain ,art of the ,owerhouse consists of three floorsacco//o)ating the turbines at the floor at an ele-ation of L 11: /asl. This floor will also be

use) for the ins,ection of the turbine shaft. The generator floor will be locate) at an ele-ationof L 11:<.;0 The /ain floor at the ele-ation L 11;*.;1 will consists of the erection bawhich facilitates the asse/bl an) erection of the turbine an) generator co/,onents )uring theconstruction ,erio) an) also )uring future o,eration an) /aintenance ,erio)s. S,ace is also





,ro-i)e) at this le-el for -ehicular access asse/bl of the )raft tube liner turbine staring an)hea) co-er /ain shaft gui)e bearing an) rotor. This area ser-es as a la )own area for therunner. The wor(sho, will also be locate) at the erection ba le-el on the south eastern si)e of

the ,owerhouse. The control roo/ will be locate) at an ele-ation of L 11;*.;1.

-+2+1+15 Tailra%e Channel and Outlet !tru%ture

The tailrace of $,,er "ahughat 4)roelectric Project will consist of a tailrace ,on) locate)i//e)iatel )ownstrea/ of the ,owerhouse which will channeli9e the flow into the (hola. This

tailrace ,on) will be +. / wi)e an) a,,roxi/atel * / long. A -er short channel aligne)with the )ownstrea/ unit will then )irectl )ischarge the flow into "ahughat =hola.

-+2+1+1? !wit%hyard

A surface switchar) has been ,ro,ose) on a co/,arati-el less stee, area abo-e the ,owerhouse so that the length of the ,ower cable an) ancillar e>ui,/ent will be short. Theswitchar) will be 0 / in length an) +0 / in wi)th.

-+2+1+1. '%%ess Road

$,,er "ahughat 4)roelectric Project is a casca)e )e-elo,/ent ,roject an) )oes not ha-e a

/otorable access roa) at ,resent. The nearest roa)hea) to this ,roject is an earthen roa) thatstarts fro/ &aleshor an) en)s at =ha,sin)a)a -ia 7auwa,hant. This roa) is about (/ long.There is an existing roa) fro/ 'eni to 3o/so/. &aleshwor lies about * (/ north of 'eni onthis 'eni % 3o/so/ roa). t lies at the confluence of "ahughat =hola an) =aligan)a(i "i-er.'eni the )istrict hea) >uarter of 7ag)i District is accessible b a 1* (/ long gra-el roa) thatoriginates fro/ 7al Dhunga on Po(hara 'aglung 4ighwa.

As /entione) earlier !A is currentl constructing "ahughat 4)roelectric Project thehea)wor(s structure of which is locate) about :00 / )ownstrea/ of the ,owerhouse site

,ro,ose) for this ,roject. t is en-isage) that the access roa) u, to the hea)wor(s site of this"ahughat 4)roelectric Project being i/,le/ente) b !A will alrea) be in ,lace before thei/,le/entation of $,,er "ahghat 4)roelectric Project. A -illage roa) which is fairl wi)eexists at ,resent fro/ 7awa,hant?=ha,si)an)a u, to Chi/ =hola -illage which is locate) atthe confluence of 'agar =hola an) "ahughat =hola. The length of this roa) is a,,roxi/atel20 (/. The area u,strea/ of 'agar =hola an) "ahughat =hola is the ,ro,ose) site for thehea)wor(s of $"4P an) the ,owerhouse site of "74P. t is therefore en-isage) thata,,roxi/atel 20 (/ of access roa) will be re>uire) for the i/,le/entation of the ,roject.

A,art fro/ this access roa) ,roject roa)s will be re>uire) to gain access to the following ,roject areas.





• The ,owerhouse area

• The switchar) area

• The )ro, shaft ,ortal area• The hea)race tunnel outlet ,ortal area

• The to, of the surgetan( area

• The hea)wor(s area at 'agar =hola

t is en-isage) that about ; (/ of internal ,roject roa) will nee) to be constructe) to ha-eaccess to these sites. t is also en-isage) that a further 1 (/ of ,roject roa) will be re>uire) to

reach the inlet ,ortals of the three a)it tunnels.

The ,roject will therefore nee) to construct 2; (/ of roa) out of which 20 (/ will consist of anew access roa) an) a further ; (/ will consist of ,roject roa)s to access the )ifferentconstruction sites.

-+2+2 $ydrauli% !teel !tru%tures

-+2+2+1 >eneral

4)raulic steel structures of the Project /ainl consist of the following

% Di-ersion structure co/,rising of an un)er sluice gate an) sto,log B'agar (hola% "i-er nta(e structures co/,rising of gra-el tra, trashrac( inta(e gate an) sto,log

B'agar (hola% Flushing gates at )esan)er B'agar (hola% Penstoc( nlet &ates B'agar (hola% Penstoc( ,i,es B'agar (hola% Tailrace outlet Sto,logs B'agar (hola% Tailrace outlet Sto,log B"ahughat 7angale% Trashrac( 4ea)race tunnel inlet gate B$,,er "ahughat% /ergenc closing 5al-e B$,,er "ahughat% Penstoc( ,i,e an) accessories B$,,er "ahughat% Power house outlet Sto,log B$,,er "ahughat

-+2+2+2 8esi#n Criteria

The )esign an) stu)ies for the h)raulic steel structures of the ,roject were carrie) out inconjunction with the )esign of the ci-il wor(s the electrical an) /echanical e>ui,/ent. The





basis for )esign was a set of )esign criteria which will ensure that each structure will /eetstringent safet stan)ar)s an) confir/ to the associate) ci-il structures electrical an)/echanical e>ui,/ent.

The h)raulic steel structures were )esigne) in accor)ance with the ,re-ailing stan)ar)s an)co)es of ,ractice such as S D! etc. The ,rinci,al )i/ensions an) )etails of each of theh)raulic steel structures are ,resente) in the following.

-+2+2+ "nder !lui%e >ate <a#ar Khola=

As the un)er sluice gate is loa)e) fro/ the u,strea/ face an) is conse>uentl re>uire) to o,enan) close un)er unbalance) con)itions as well as for floo) releasing an) water le-el regulation)uring wet an) )r season -ertical lift wheel gate is ,ro,ose). The un)er sluice of the)i-ersion weir structure will be e>ui,,e) with one set of * / wi)e an) 2.1 / high -ertical lift

gate.

The gate will be of wel)e) construction t,e -ertical lift wheel gate. The gate consists of u,strea/ s(in ,late /ain bea/s wheel asse/blies sealing arrange/ent gui)e shoesrollers lifting bea/ an) other necessar co/,onents. All the steel /aterials co/,onents

bolts gui)e fra/es will be of corrosion resistant steel. The gate shall o,erate at the /osta)-erse con)ition of loa)s. The gate will be o,erate) b electricall o,erate) screw s,in)let,e with ,ro-ision of /anual o,eration.

The ,rinci,le characteristics of the inta(e gates are as follows

T,e of gate 5ertical lift wheel gate

!u/ber of gate #ne B1 setClear s,an of o,ening *.0 /Clear height of o,ening 2.1 /Design water le-el 1:0.; /aslSill le-el 1*. /aslDesign hea) Full )esign water hea) of :.* / an)

se)i/entar loa)8ater tightness + )ges seal at u,strea/4oist t,e lectrical screw s,in)le hoist with ,ro-ision

of /anual o,eration7aterial 3S % SS+1 S7+1 or e>ui-alent





-+2+2+5 "nder !lui%e !toplo# <a#ar Khola=

#ne set of sto,log will be ,ro-i)e) for closing the un)er sluice gate for /aintenance an)

re,airing of the un)er sluice gate. The sto,log is locate) at an a,,ro,riate )istance u,strea/ of the -ertical lift gate to ,er/it access to the u,strea/ face of gate. This o,eration will beeffecti-e un)er balance) u,strea/ an) )ownstrea/ water ,ressure.

The sto,log will be of wel)e) construction. The s(in ,late an) seal arrang/ent will be ,ro-i)e)on u,strea/ si)e. The sto,log will be store) ,artl in the u,,er section of the sto,log slot an)in se,arate ,its near sto,log slot at weir structure. The e/be))e) ,arts will inclu)e the gui)ean) seal fra/es as well as )ogging )e-ice for storage in the slots an) in the res,ecti-e storage.

The sto,log will ha-e /usic note seals against the e/be))e) -ertical /etal gui)es an)hori9ontal co/,ression rubber seals between the sto,log ,anels. All the sealing faces will be

/a)e of corrosion resisting steel.

The ,rinci,le characteristics of the un)er sluice sto,log are as follows

T,e of sto,log 5ertical lift sli)e sto,log !u/ber of sto,log #ne B1 set !u/ber of sto,log ,anels Two to threeClear s,an *.0 /Clear height 2.1 /Design water le-el 1:0.; /aslSill le-el 1*. /asl

Design hea) :.* /8ater tightness + )ges seal at u,strea/4oist t,e lectrical /otor o,erate) /ono rail hoist

with ,ro-ision of /anual o,eration7aterial 3S % SS+1 S7+1 or e>ui-alent

t is ex,ecte) that the nu/ber of sto,log ,anel will be between 2 an) * an) the actual heightwill be )e,en)ent u,on the hoisting arrange/ent an) ca,acit on site storage facilities an)trans,ortation li/itations. n -iew of the high hea) to which the lower sto,log ,anel will besubjecte) it is antici,ate) that the -arious ,anels will be )esigne) to be installe) in a

,articular or)er. n this wa the u,,er ,anels can be )esigne) for a lower loa)ing.

lectrical /otor o,erate) /ono rail hoist with ,ro-ision of /anual o,eration with asu,,orting structure anchore) to the )ec( will be ,ro-i)e) for the sto,log.

-+2+2+? >ra*el Trap >ate <a#ar Khola=

#ne set of -ertical sli)e gate will be ,ro-i)e) at gra-el flushing structure for flushing gra-elan) hea- san) ,articles to the ri-er an) to ,re-ent the hea- ,articles to ,ass to the inta(estructure. The gate will consist of gate leaf gui)e fra/e hoisting e>ui,/ent. The gate leaf will consist of hea- s(in ,late u,strea/ rubber seals lifting attach/ents an) other necessar co/,onents.





The gate leaf will be /a)e of single structural steel ,late. The thic(ness of the ,late will besufficient to withstan) the re>uire) loa). The gui)e fra/e of gate will consists of a sill bea/two si)e fra/es an) lintel bea/.

The gate will be o,erate) b electricall o,erate) screw s,in)le t,e with ,ro-ision of /anual o,eration.

The ,rinci,le characteristics of the gates are as follows

T,e of gate Sli)e gate !u/ber of gate #neClear s,an 1.0 /Clear height 1. /Design water le-el 1:0.; /asl

Sill le-el 1*. /aslDesign hea) :.* /8ater tightness + )ges seal at u,strea/4oist t,e lectric /otor o,erate) s,in)le hoist with

,ro-ision of /anual o,eration7aterial 3S % SS+1 S7+1 or e>ui-alent

-+2+2+. >ra*eltrap !toplo# <a#ar Khola=

#ne set of sto,log will be ,ro-i)e) for closing the gra-eltra, gate for /aintenance an)

re,airing of the gate. The sto,log is locate) at an a,,ro,riate )istance u,strea/ of the -erticallift gate to ,er/it access to the u,strea/ face of gate. This o,eration will be effecti-e un)er

balance) u,strea/ an) )ownstrea/ water ,ressure.

The sto,log will be of wel)e) construction. The s(in ,late an) seal arrang/ent will be ,ro-i)e)on u,strea/ si)e. The sto,log will be store) ,artl in the u,,er section of the sto,log slot an)in se,arate ,its near sto,log slot at weir structure. The e/be))e) ,arts will inclu)e the gui)ean) seal fra/es as well as )ogging )e-ice for storage in the slots an) in the res,ecti-e storage.

The sto,log will ha-e /usic note seals against the e/be))e) -ertical /etal gui)es an)hori9ontal co/,ression rubber seals between the sto,log ,anels. All the sealing face will be/a)e of corrosion resisting steel.

The ,rinci,le characteristics of the un)er sluice sto,log are as follows

T,e of sto,log 5ertical lift sli)e sto,log !u/ber of sto,log #ne B1 set !u/ber of sto,log ,anels #ne to twoClear s,an 1.0 /Clear height 1. /Design water le-el 1:0.; /asl

Sill le-el 1*. /aslDesign hea) :.* /8ater tightness + )ges seal at u,strea/





4oist t,e lectrical /otor o,erate) /ono rail hoistwith ,ro-ision of /anual o,eration

7aterial 3S % SS+1 S7+1 or e>ui-alent

t is ex,ecte) that the nu/ber of sto,log ,anels will be between 1 an) 2 the actual heightwill be )e,en)ent u,on the hoisting arrange/ent an) ca,acit on site storage facilities an)trans,ortation li/itations. n -iew of the high hea) to which the lower sto,log ,anel will besubjecte) it is antici,ate) that the -arious ,anels will be )esigne) to be installe) in a



-+2+2+4 :nta/e Trashra%/ <a#ar Khola=

To chec( the floating )ebris an) sus,en)e) /aterials fro/ entering into the inta(e water wasthe whole length of inta(e is co-ere) with one set of trashrac( with a clear wi)th of / an) aheight of 2. /.

The trashrac( will also ,rotect the hu/an or ani/al life if the acci)entall fall in the ri-er.The clear o,ening of the bars will be sufficient to ,ass the flow into the canal an) will ,re-entthe flow of unwante) /atter such as logs trees branch etc. The screen will be of the non%with)rawal t,e consisting of fixe) installe) screen ,anels su,,orte) b a strea/line)trans-erse bea/. The co/,lete trashrac(s an) e/be))e) ,arts will be /a)e of nor/al steel

,ro-i)e) with a suitable ,rotection coat.

The trash rac( will be )esigne) to withstan) the i/,act forces static loa) an) -ibration

,heno/enon which are li(el to occur )ue to the flow of water through the trash rac(.

The /ain characteristics of the inta(e trashrac(s will be as follows

T,e Fixe) trash rac( !u/ber of trashrac(s #ne set'ar ,itch 0 //Clear s,an .0 /

Clear height 2. /nclination angle :° Sill le-el 1 /asl8ater loa) on bar ele/ent 1. (g?c/Corrosion allowance 2 // for all ex,ose) surfaces in water 7aterial 3S % SS+1 or other e>ui-alent

-+2+2+6 :nta/e !lui%e >ate <a#ar Khola=

The /ain ,ur,ose of the inta(e gate is to regulate the flow )uring the rain season. t alsoregulates the )ischarge in the con)uit an) to close the flow )uring the /aintenance of the sa/e.

The gate will be of wel)e) construction t,e -ertical lift sluice gate. The gate consist of )ownstrea/ s(in ,late /ain bea/s wheel asse/blies sealing arrange/ent gui)e shoes





rollers lifting bea/ an) other necessar co/,onents. All the steel /aterials co/,onents bolts gui)e fra/es will be of corrosion resistant steel. The gate will be o,erate) belectricall o,erate) screw s,in)le t,e with ,ro-ision of /anual o,eration.


T,e of gate 5ertical lift sluice gate !u/ber of gate #neClear s,an *. /Clear height 0. /Design water le-el 1:0.; /aslSill le-el 1 /aslDesign hea) .; /8ater tightness + )ges seal at u,strea/

4oist t,e lectrical screw s,in)le hoist with ,ro-ision of/anual o,eration


-+2+2+- :nta/e !toplo# <a#ar Khola=

#ne set of sto,log will be ,ro-i)e) at inta(e in or)er to isolate the ri-er an) ,ower flows for re,airing an) /aintenance of inta(e gate.

The sto,log will be of wel)e) construction. The s(in ,late an) seal arrang/ent will be ,ro-i)e)

on u,strea/ si)e The sto,logs will ha-e /usic note seals against the e/be))e) -ertical /etalgui)es an) hori9ontal co/,ression rubber seals between the sto,log ,anels an) at the botto/.

The sto,log will be store) ,artl in the u,,er section of the sto,log in )ogging )e-ice. Thee/be))e) ,arts will inclu)e the gui)e an) seal fra/es as well as )ogging )e-ice for storage inthe slots an) in the res,ecti-e storage.

t is ex,ecte) that the nu/ber of sto,log ,anels will be between 1 an) 2 the actual heightwill be )e,en)ent u,on the hoisting arrange/ent an) ca,acit on site storage facilities an)trans,ortation li/itations. n -iew of the high hea) to which the lower sto,log ,anel will be

subjecte) it is antici,ate) that the -arious ,anels will be )esigne) to be installe) in a ,articular or)er. n this wa the u,,er ,anels can be )esigne) for a lower loa)ing.


The ,rinci,le characteristics of the inta(e sto,log are as follows

T,e of gate 5ertical lift sto,log

!u/ber of sto,log #ne set !u/ber of sto,log ,anels #ne to twoClear s,an *. /Clear height 0. /





Design water le-el 1:0.; /aslSill le-el 1 /aslDesign hea) .; /

8ater tightness + )ges seal at u,strea/4oist t,e lectrical /otor o,erate) /ono rail hoistwith ,ro-ision of /anual o,eration


-+2+2+10 8esander Flushin# >ate <a#ar Khola=

#ne set of -ertical lift sli)e t,e flushing gate with its gui)e fra/e hoist an) a,,urtenant ,artsco/,lete with all necessar accessories will be ,ro-i)e) in the )esan)er flushing structure. The/ain function of this gate is to be use) for flushing of the san) )uring regular inter-al an)

/aintenance ,erio).

The flushing gate is re>uire) to be o,en against an unbalance) hea) to initiate the flushing ,rocess an) to be close) at the en) of the flushing ,rocess when the )esan)er is e/,t.

The gate will be of wel)e) construction. The s(in ,late an) sealing arrange/ent will be onu,strea/ si)e. The four wa seal will be such that there will be no water lea(age )uring the fullswing o,eration of the )esan)er.

The gate will be electricall o,erate) screw s,in)le t,e with ,ro-ision of /anual o,eration.The ,rinci,le characteristics of the gates are as follows

T,e of gate 5ertical lift sli)e gate !u/ber of gate #ne setClear s,an 1.0 /Clear height 1. /Design water le-el 1;.2 /aslSill le-el 11.*; /aslDesign hea) .< /8ater tightness + )ges seal at u,strea/4oist t,e lectric /otor o,erate) s,in)le hoist


-+2+2+11 Pensto%/ :nlet >ates

To regulate the flow in to the steel ,enstoc( ,i,es an) e/ergenc shut off the water inflow tothe ,enstoc( ,i,es a -ertical lift wheel gates will be ,ro-i)e) at inlet ,ortal.

The gate will be of wel)e) construction t,e -ertical lift wheel gates. The gates consist of )ownstrea/ s(in ,late /ain bea/s wheel asse/blies sealing arrange/ent gui)e shoesrollers lifting bea/ an) other necessar co/,onents. All the steel /aterials co/,onents

bolts gui)e fra/es will be of corrosion resistant steel. The gate shall o,erate at the /osta)-erse con)ition of loa)s. The gate will be o,erate) b electricall o,erate) screw s,in)let,e with ,ro-ision of /anual o,eration.





The /ain characteristics of the gate are as follows

T,e of gate 5ertical Lift 8heel &ates !u/ber of gates Two B2 setsClear s,an 1.2 /Clear height 1.2 /Design water le-el 1;.2 /aslSill le-el 11.;1 /asl.Design water hea) .+ /8ater tightness + )ges seal at u, strea/4oist t,e lectric /otor o,erate) s,in)le hoist


-+2+2+12 Tailra%e Outlet !toplo#s <a#ar Khola=

Two sets of sto,logs will be ,ro-i)e) at tailrace outlet for /aintenance ,ur,oses.

The sto,log will be of wel)e) construction. The s(in ,late an) seal arrange/ent will be ,ro-i)e) on u,strea/ si)e. Sto,logs will ha-e /usic note seals against the e/be))e) -ertical/etal gui)es an) hori9ontal co/,ression rubber seals between the sto,log ,anels an) at the

botto/. The sto,log will be store) ,artl in the u,,er section of the sto,log in a )ogging)e-ice. The e/be))e) ,arts will inclu)e the gui)e an) seal fra/es as well as )ogging )e-icefor storage in the slots an) in the res,ecti-e storage.

t is ex,ecte) that the nu/ber of sto,log ,anels will be between 1 an) 2 the actual heightwill be )e,en)ent u,on the hoisting arrange/ent an) ca,acit on site storage facilities an)trans,ortation li/itations. n -iew of the high hea) to which the lower sto,log ,anel will besubjecte) it is antici,ate) that the -arious ,anels will be )esigne) to be installe) in a


A ,er/anent /onorail electric hoist co/,lete with a su,,orting structure anchore) to the ,ower house wall an) s,anning across will be ,ro-i)e) for the gates.


T,e of gate 5ertical lift sto,lag !u/ber of sto,log Two sets !u/ber of sto,log ,anels one to twoClear s,an 2.2 /Clear height 0. /

Design water le-el 1+. /aslSill le-el 1++.* /aslDesign hea) 10.2 /8ater tightness + )ges seal at u,strea/





4oist t,e lectrical /otor o,erate) /ono railhoist with ,ro-ision of /anualo,eration


-+2+2+1 Tailra%e outlet !toplo# <Rahu#hat Man#ale=

#ne set of sto,log will be ,ro-i)e) at tailrace outlet in or)er to sto, flow into the collectionsu/,?cha/ber at the ti/e of shut)own of the ,ower ,lant an) for /aintenance ,ur,oses.

The sto,log will be of wel)e) construction. The s(in ,late an) seal arrange/ent will be ,ro-i)e) on u,strea/ si)e. Sto,log will ha-e /usic note seals against the e/be))e) -ertical/etal gui)es an) hori9ontal co/,ression rubber seals between the sto,log ,anels an) at the

botto/. The sto,log will be store) ,artl in the u,,er section of the sto,log in )ogging )e-ice.The e/be))e) ,arts will inclu)e the gui)e an) seal fra/es as well as )ogging )e-ice for storage in the slots an) in the res,ecti-e storage.

t is ex,ecte) that the nu/ber of sto,log ,anels will be between * an) the actual heightwill be )e,en)ent u,on the hoisting arrange/ent an) ca,acit on site storage facilities an)trans,ortation li/itations. n -iew of the high hea) to which the lower sto,log ,anel will besubjecte) it is antici,ate) that the -arious ,anels will be )esigne) to be installe) in a




T,e of gate 5ertical lift sto,lag !u/ber of sto,log #ne B1 set !u/ber of sto,log ,anels Three to fi-eClear s,an *.2 /Clear height *.2 /Design water le-el 1+.; /asl

Sill le-el 1+<.; /aslDesign hea) /8ater tightness * )ges seal at u,strea/4oist t,e lectrical /otor o,erate) /ono rail

hoist with ,ro-ision of /anualo,eration






-+2+2+15 Colle%tion Chamer Trashra%/ <"pper Rahu#hat=

To chec( the floating )ebris an) sus,en)e) /aterials fro/ entering into the waterwas the

inlet of hea)race tunnel is co-ere) with one set of trashrac( with a clear wi)th *.+ / an) heightof *.+ /.

The trashrac( will also ,rotect the hu/an or ani/al life if the acci)entall fall in thewaterwa. The clear o,ening of the bars will be sufficient to ,ass the flow into the cul-ert an)will ,re-ent the flow of unwante) /atter such as logs trees branch etc. The screen will be of the non%with)raw t,e consisting of fixe) installe) screen ,anels su,,orte) b a strea/line)trans-erse bea/. The co/,lete set of trashrac( an) e/be))e) ,arts will be /a)e of nor/alsteel ,ro-i)e) with a suitable ,rotection coat. The trash rac( will be )esigne) to withstan) the static loa) an) -ibration ,heno/enon which

are li(el to occur )ue to the flow of water through the trash rac(.

The /ain characteristics of the trashrac(s will be as follows

T,e Fixe) trash rac( !u/ber of trashrac(s #ne set'ar ,itch :0 //Clear s,an *.+ /Clear height *.+ /nclination angle :° Sill le-el 1+.* /asl8ater loa) on bar ele/ent 1. (g?c/Corrosion allowance 2 // for all ex,ose) surfaces in water 7aterial 3S % SS+1 or other e>ui-alent

-+2+2+1? Tunnel :nlet >ate <"pper Rahu#hat=

The /ain ,ur,ose of the inlet gate is to regulate the flow in the water was an) to close theflow )uring the /aintenance of the sa/e.

The gate will be of wel)e) construction t,e -ertical lift wheel gates. The gate consist of u,strea/ s(in ,late /ain bea/s wheel asse/blies sealing arrange/ent gui)e shoesrollers lifting bea/ an) other necessar co/,onents. All the steel /aterials co/,onents

bolts gui)e fra/es will be of corrosion resistant steel. The gate will be o,erate) belectricall o,erate) screw s,in)le t,e with ,ro-ision of /anual o,eration.


T,e of gate 5ertical lift wheel gates !u/ber of gate #neClear s,an *.+ /Clear height *.+ /





Design water le-el 1+. /aslSill le-el 1+.* /aslDesign hea) <.2 /

8ater tightness + )ges seal at u,strea/4oist t,e lectrical screw s,in)le hoist with ,ro-ision of/anual o,eration


-+2+2+1. )mer#en%y Closin# Val*e <"pper Rahu#hat=

An e/ergenc closing -al-e will be ,ro-i)e) in a -al-e cha/ber locate) a,,roxi/atel 12 /)ownstrea/ of the surgetan( for e/ergenc closure of water flow in case of turbine /ain inlet-al-e failure or colla,sing of the ,enstoc( ,i,e the -al-e will be use) as well to e/,t the

,enstoc( ,i,e without re>uiring the )e%watering of the hea)race tunnel. The -al-es shall be of

the lattice bla)e butterfl t,e with a )ia/eter of 2+00 //.

5al-e control will nor/all be carrie) out b o-er%s,ee) )etection with a ,ro-ision for localcontrol or b re/ote control b a ,ush button locate) in the ,owerhouse control roo/. The-al-e closure will be )one b a counterweight. #,ening of the -al-e will be )one b ah)raulic clin)er. !or/al -al-e closure will be controlle) b the o-er%s,ee) )etector an) willoccur against the flow. The -al-e will be o,ene) un)er balance) con)itions onl.

The connection ,i,e will be ,ro-i)e) with a /anhole 00 // in )ia/eter the co-er of whichshall be securel bolte) to the /anhole flange with a watertight joint an) ,ro-i)e) witha,,ro,riate facilities for o,ening.

A b%,ass -al-e will be ,ro-i)e) to fill the ,enstoc( ,i,e.

Air inlet?relief -al-e will be ,ro-i)e) with an isolating -al-e. The air -al-e will be of a suitable)ia/eter for allowing high ,ressure ,i,e )e%watering within the guarantee) ti/e.

The ,rinci,le characteristics of the -al-e is as follows

nternal )ia/eter 2.+ /Design )ischarge 1.2 /*?secFSL at hea) ,on) l.1+. /asl5al-e center le-el l. 12:. /asl4ighest u,surge le-el in the surge tan( l. 1:.12 /aslStatic hea) 2.< /

-+2+2+14 Tailra%e outlet !toplo# <"pper Rahu#hat=

#ne set of sto,log will be ,ro-i)e) at tailrace outlet in or)er to ,re-ent the high floo) of theri-er entering into the ,owerhouse an) for /aintenance ,ur,oses.

The sto,log will be of wel)e) construction. The s(in ,late an) seal arrang/ent will be ,ro-i)e)on the u,strea/ si)e. The sto,logs will ha-e /usic note seals against the e/be))e) -ertical/etal gui)es an) hori9ontal co/,ression rubber seals between the sto,log ,anels an) at the

botto/. The sto,log will be store) ,artl in the u,,er section of the sto,log in )ogging )e-ice.





The e/be))e) ,arts will inclu)e the gui)e an) seal fra/es as well as )ogging )e-ice for storage in the slots an) in the res,ecti-e storage.

t is ex,ecte) that the nu/ber of sto,log ,anels will be between * an) the actual heightwill be )e,en)ent u,on the hoisting arrange/ent an) ca,acit on site storage facilities an)trans,ortation li/itations. n -iew of the high hea) to which the lower sto,log ,anel will besubjecte) it is antici,ate) that the -arious ,anels will be )esigne) to be installe) in a




T,e of gate 5ertical lift sto,lag !u/ber of sto,log Two set !u/ber of sto,log ,anels Three to sixClear s,an *. /Clear height *. /Design water le-el 11:.; /aslSill le-el 11;.:< /aslDesign hea) ;.:+ /8ater tightness + )ges seal at u,strea/4oist t,e lectrical /otor o,erate) /ono rail hoist with

,ro-ision of /anual o,eration7aterial 3S % SS+1 S7+1 or e>ui-alent

-+2+ 9ater 9ays

-+2++1 !teel Pensto%/ <a#ar Khola=

Penstoc( inlets will be ,ro-i)e) at the en) of the foreba to fee) the 'agar =hola ,owerhouse.Two surface steel ,enstoc( ,i,es will be ,ro-i)e) to con-e water un)er ,ressure to theturbines in)i-i)uall. The steel ,enstoc( consists of straight ,i,es ben) ,i,es stiffener ringssee,age rings thrust rings )rain ,i,es /anholes an) all other necessar accessories. The

insi)e )ia/eter of the ,enstoc( ,i,es are 1.2 / an) the thic(ness of the steel ,i,e will be ; //.The thic(ness of the ,i,e shell shall be )esigne) to resist both the internal an) external ,ressurean) other loa)s. The thic(ness of ,enstoc( ,i,e is /ainl go-erne) b han)ling re>uire/ent asco/,are) to internal ,ressure an) external ,ressure so ta(ing into this consi)eration intoaccount. The steel /aterials use) will be 3S S7+1' or e>ui-alent.

The length of each ,enstoc( ,i,e is a,,roxi/atel 20 /.Anchor bloc(s will be ,ro-i)e) at theto, an) the botto/ of the ,enstoc( ,i,e to ,ro-i)e necessar weight to counteract the resultantto all forces an) to trans/it then safet to the groun).

The thrust rings will be wel)e) to the ,i,es an) will ha-e the strength sufficient enough for transferring axial thrust to the surroun)ing concrete. Three see,age rings shall be ,ro-i)e) at





the beginning ,ortion of a ,enstoc(. A /anhole of 00 // )ia/eter in si9e will be ,ro-i)e) onthe ,enstoc( at suitable locations for ins,ection an) /aintenance of ,i,es.

The ,enstoc( ,rofile is shown in Drawing !o. $"%'P4%1.

The ,rinci,le characteristics of the steel ,enstoc(

T,e Surface T,euantit #ne laneLength of ,enstoc( ,i,e 20 /7aterial Steel 3S S7+1' or e>ui-alentAllowable stress 1200 (g?c/2

nternal )ia/eter Penstoc( 1.2 /Design )ischarge *.2 /*?sec

!et hea) 12.< /Static hea) 12. /Shell Thic(ness Penstoc( ; // BS7+1S,iral case inlet center le-el 1+.< /aslFull Su,,l Le-el 1:. /asl

-+2++2 !teel Pensto%/ and !teel iner <"pper Rahu#hat=

Fro/ the collection su/,?cha/ber the water is con-ee) to the ,owerhouse through thehea)race tunnel surge tan( ,enstoc( an) steel line) )ro, shaft. A steel ,enstoc( ,i,e an) steelliner is ,ro-i)e) to con-e water un)er ,ressure to the turbine. The steel ,enstoc( an) liner

consist of straight ,i,es ben) ,i,es bifurcation re)ucing ,i,es ex,ansion joints stiffener rings see,age rings thrust rings )rain ,i,es /anholes an) all other necessar accessories. The

insi)e )ia/eter of ,enstoc( ,i,e an) steel liner will be 2.+ / u, to the bifurcation an) thic(nessof steel ,enstoc( -aries fro/ ; // to 2+ // an) those of steel liner -aries fro/ 2+ // to//. The thic(ness of the ,i,e shell shall be )esigne) to resist both the internal an) external

,ressure an) other loa)s. The thic(ness is calculate) ta(ing into account the water ha//er effects. The steel /aterials use) will be 3S S7+1' an) S70' or e>ui-alent.

The length of the ,enstoc( ,i,e is about *; / length of steel liner is *** an) a-erage lengthof the bifurcation ,i,es will be about 22 /eter each.

A total of nu/bers of anchor bloc(s will be ,ro-i)e) at each change of )irection of the ,enstoc( ,i,e an) steel liner to ,ro-i)e necessar weight to counteract the resultant to all forcesan) to trans/it then safet to the groun). x,ansion joints are ,ro-i)e) just )ownstrea/ of each anchor bloc(s to co,e the ,roble/ cause) b ther/al ex,ansion. The thrust rings will be wel)e) to the ,i,es an) ha-e sufficient strength for transferring axialthrust to surroun)ing concrete. Three see,age rings shall be ,ro-i)e) at the beginning ,ortionof a ,enstoc(. A circular /anhole of 0 // )ia/eter in si9e will be ,ro-i)e) on the ,enstoc( at e-er anchor bloc( location or other suitable locations for ins,ection an) /aintenance of the

,i,es.





-+2++ i7ur%ation Pipe

A s//etrical 6 bifurcation will be ,ro-i)e) ,arallel to the )irection of the /ain ,i,e to fee)

the ,owerhouse. The internal angle between the two branching ,i,es will be a,,roxi/atel ;0)egrees. The ,enstoc( an) steel liner ,rofile is shown in Drawing !o. $"%PS%01.

The ,rinci,le characteristics of the steel lining an) ,enstoc(

T,e Surface ,enstoc( an) e/be))e)

T,e steel liner uantit #ne lane

Length of ,enstoc( ,i,e *; /Length of steel liner **: /7aterial Steel 3S S7+1' S70' an)

or e>ui-alentAllowable stress 1200 1:0 (g?c/2

nternal )ia/eter Penstoc( 2.+ /Steel liner 2.+ /Design )ischarge 1.2 /*?sec

!et hea) *:2.* /

Static hea) *:;.0 /7axi/u/ )esign hea) +*+.: / Binclu)ing water ha//er

Shell Thic(nessPenstoc( 10 // to 2 // BS7+1'Steel liner 1< // to * // BS70'

'ifurcation ,i,en) ,i,e )ia/eter 1.: /Length 22 / B2 lanesThic(ness *0 // BS70'

Full Su,,l Le-el 1+. /aslTurbine center le-el 11:. /asl

-+2+5 Powerhouse )le%tro Me%hani%al )Guipment

-+2+5+1 Plant Capa%ity

The installe) ca,acit of the ,roject is calculate) to be +;00 (8 at the generator ter/inal. Theinstalle) ca,acit is base) on the results of the o,ti/i9ation stu) an) is an a,,roxi/ate -alue.De,en)ing on the efficienc of the su,,lie) /achiner the calculate) out,ut ca,acit coul)show /inor )ifferences.





-+2+5+2 Numer o7 "nits and "nit Capa%ity

Se-eral ele/ents affect the nu/ber of units chosen for h)ro ,ower ,rojects such as the

characteristic of the interconnecting sste/ the /aintenance /etho)s an) the total costin-este) in the ,roject. The nor/al )ecision for the nu/ber of units to be chosen is bcon)ucting an econo/ic analsis. A single unit is not ,referre) )ue to the fact that generationloss will occur )uring unit brea()own or /aintenance of the units. $nit ca,acit is generall)eter/ine) b consi)ering the a-ailable )ischarge throughout the seasons loa) )e/an) t,e of o,erations efficienc of the /achine etc. The selection of two units is /ore suitableconsi)ering the )ischarge )uring the )r season. So a two unit installation has been a)o,te).

'ase) on the o,ti/u/ ca,acit of +;00 (8 an) the two nu/ber of units the rate) out,ut of each unit has been selecte) at 2+20 =8 with a rate) net hea) of *:2.1 / an) a rate) flow of :. /*?sec.

n calculating the re>uire) turbine an) generator ,ower out,uts for this stu) the following-alues of efficienc were assu/e) on the basis of the su,,lierHs )ata a-ailable for si/ilar si9e)units.

Turbine <0 O&enerator <: O

-+2+5+ !ele%tion o7 the Turine Type

n ,ractice -arious ,roce)ures are use) for the selection of the t,e of turbines. Fro/ $S'"

turbine selection gra,h of hea) -erses )ischarge the selection of a -ertical axis ,elton turbinewith four jets constitutes the best o,tion for this ,roject on the basis of a rate) net hea) of *:2.* / an) a )ischarge of :. /*?sec.

The ,elton turbine with + jets ha-e the following a)-antages

% Less s,ace is re>uire) for installation with s/aller si9e of units )ue to higher s,ee)selection.

% The a-erage efficienc is high in general an) /ost suitable for ,art loa) o,eration.% The o,eration an) /aintenance of the ,lant is easier.

-+2+5+5 !pe%i7i% !peed and !yn%hronus !peed

The calculate) s,ecific s,ee) li/it ,er jet for the gi-en rate) hea) is 21.*2 (8%/. Thecorres,on)ing turbine s,ee) li/it is ++1.+2 r,/. The snchronous s,ee) /ust be selecte) onthe basis of the nu/ber of the generator ,oles an) the networ( fre>uenc. "ecent ,ractice is toa)o,t higher s,ecific s,ee)s an) this will also increase the snchronous s,ee). The e>ui,/entsi9e will be s/aller an) its weight will be re)uce) thereb /a(ing it /ore econo/ical. 'ase)on the abo-e criteria the rate) snchronous s,ee) is calculate) to be +2;.: r,/ which is ahigher a,,licable s,ee) within the li/it of the turbine s,ee). So the corres,on)ing actuals,ecific s,ee) of the turbine at the rate) hea) is 20.: (8%/.





-+2+5+? 8es%ription o7 the Turines

The turbines will be of the -ertical shaft single runner ,elton t,e with four jets. The turbinewill be e>ui,,e) with no99les an) )eflectors for regulation of ,ower out,ut an) control of s,ee) for starting snchroni9ing an) shut )own.

The ,elton runner will be cou,le) to the A.C. generators shaft through the turbine shaft. The ,elton turbine will be of four no99le t,e an) the no99le will be actuate) b oil ,ressure sste/which will be /a)e of -er high >ualit stainless steel. The water jet in the turbine will be)eflecte) b a )eflector which will act -er fast. The turbine will be e>ui,,e) with turbinehousing which will gui)e the ,ressure release) water fro/ the runner to the tailrace safel. Theturbine?generator unit will be sto,,e) with the hel, of bra(e no99le ,ro-i)e) at the turbine

housing an) a h)raulic or ,neu/atic bra(e ,ro-i)e) in the generator.

All the turbine instru/entation such as the unit control boar)s an) the go-ernor controlcabinets will be locate) close to the rele-ant units on the turbine floor. This is a)-antageous for co//issioning ser-ice an) /aintenance.

-+2+5+. Prin%ipal Chara%teristi%s

The ,rinci,al characteristics of the selecte) hori9ontal shaft t,e ,elton turbines are as follows

!u/ber of turbine Two B2

!u/ber of no99le Four B+Shaft arrange/ent 5erticalnstalle) ca,acit of each turbine 2+<<: (8nstalle) ca,acit of each unit 2+20 (8Turbine fficienc <0O"ate) )ischarge for each unit :. /*?s&ross hea) *:;.00 /"ate) net hea) *:2.* /"ate) s,ee) +2;.: r,/S,ecific S,ee) ,er jet 20.: (8%/."unwa s,ee) ::0 r,/

"unner Pitch circle )ia/eter 1.:: /#uter wheel Dia/eter 2.*2 /nlet Dia/eter of Distributor 1.12 /Full su,,l le-el l 1+.0 /aslTailrace water le-el B4FL l 11:*.:1 /asl"unner center line l 11:.0 /aslPower house Crane S,an 1*. /





-+2+5+4 8es%ription o7 Main Parts

The /ain ,arts of the turbine are )escribe) below in brief.

Runner3

The turbine will be a single runner attache) with a turbine shaft for cou,ling with the flange at

the en) of the generator shaft. The /etho) of attach/ent will be )esigne) to ,er/it con-enientre/o-al of the runner. The runner will be of an integrall soli) casting steel ha-ig a /ini/u/

content of 1*O Cr an) +O !i.

The runner will be )esigne) an) constructe) to safel withstan) the stresses )ue to o,eration atrunwa s,ee) an) un)er the /ost se-ere con)itions. The h)raulic surfaces of buc(ets will becarefull groun)e) an) finishe) s/oothl.

The s,litters will be finishe) so that the will rotate in the sa/e ,lane that ,asses through thecenters of the no99le o,ening.

'olte) connection will be ,ro-i)e) for attaching the runner to the shaft. The bolts shall beloc(e) in ,osition to ,re-ent loosening )uring o,eration.

!ha7t3

The turbine shaft which will connect the runner to the generator will be /a)e of forge) steelwith ,ro,erl heat treate). The turbine will ha-e integrall forge) flanges at the en) for theconnection to a si/ilar flange on the generator shaft an) for its connection to the runner. t will be)esigne) to o,erate safel at an s,ee) u, to the /axi/u/ runwa s,ee) without )etri/ental-ibration or )istortion.

!ha7t !ealin# !ystem

The shaft seal will ,re-ent the entering of water fro/ the turbine housing into the gui)e bearing. The shaft seal will be of the axial sli)ing ring t,e or ,referabl a co/bination of labrinth t,e an) axial sli)ing ring t,e.

>uide earin#3

The turbine will be e>ui,,e) with a self lubricating oil t,e gui)e bearing without the use of external ,u/,s. The bearing house will be s,lit -erticall to ,er/it re/o-al without )is/antlingthe shaft. The bearing surfaces will be for/e) b white /etal linings either e/be))e) )irectlinto the bearing house or in re/o-able bearing seg/ents. The gui)e bearing will be of water

coole) t,e an) co/,lete with oil reser-oir an) water cooling coil. 'earing an) bearing housingwill be )esigne) to su,,ort the ra)ial loa)s at an con)ition of o,eration inclu)ing the runawas,ee).

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Power Noles and Needles3

No99les for su,,ling water to the turbine runner will be ,ro-i)e) for a )esigne) h)raulic ,ressure an) will be constructe) to ,ro)uce the /ost unifor/ jet ,ossible. The no99le bo) will be of the stress relie-e) cast steel. The bo)ies will be flange) for bolting to )istributor ,i,ing

an) to the no99le ti,s. ach no99le ti, will be ,ro-i)e) with a renewable seat ring at the final ,oint of water )ischarge. The nee)le ti, will be re,laceable an) /a)e of stainless steel an)securel loc(e) to the ste/s.

@et 8e7le%tor3

n or)er to ,re-ent excessi-e ,ressure rise in the ,enstoc( an) to ensure >uic( res,onse an) ,ower s,ee) regulation of the unit each no99le will be e>ui,,e) with a jet )eflector. This will be actuate) b an oil ser-o/otor. The )eflector will be of the cut in t,e an) will be /a)e of steel with stainless steel o-erla cutting e)ge inclu)ing the h)raulic ,assage. t will be)esigne) to safel withstan) the /axi/u/ )ischarge fro/ the no99le.

Needle and 8e7le%tor !er*omotors

The nee)le an) )eflector ser-o/otors will be of the oil ,ressure actuate) )ouble%acting t,eha-ing sufficient ca,acit to o,erate the jet )eflectors an) nee)les un)er all h)rauliccon)itions with /ini/u/ oil ,ressure fro/ the go-ernor oil sste/. A suitable fee)bac( /echanis/ will be ,ro-i)e) to trans/it the ser-o/otor /o-e/ent to the s,ee) go-ernor.

ra/e nole assemly3

ach runner will be e>ui,,e) with a bra(e no99le arrange) to )irect a strea/ of water againstthe bac(s of the buc(ets to restrain the rotating ,art of the turbine an) generator after the unit ista(en off the line. The water for the bra(ing no99le will be ta(en fro/ the turbine inlet -al-e

bo) u,strea/ of the ser-ice seal.!piral 8istriutor3

nta(e ,i,e an) the )istributor ,i,e will be /a)e of high stress steel an) will be wel)e)construction. The )istributor will be )esigne) to withstan) the /axi/u/ )esigne) ,ressure.

The )istributor inclu)ing no99le bo) extension will be ,ro-i)e) with stiffness an) anchoragessufficient to ensure that no )efor/ation will ta(e ,lace )uring erection. The )istributor will berigi)l connecte) to the inlet -al-e b /eans of flange. A water tight /anhole co-er not lessthan 00 // in )ia/eter will be ,ro-i)e so as to ,er/it con-enient ins,ection of the interior of

the inlet -al-e fro/ )own%strea/ si)e.





Turine $ousin#3

The turbine housing will consist of thei. $,,er turbine housing Brunner ,it housing The runner ,it housing ser-ing as

su,,ort for the turbine co-er with gui)e bearing will be fabricate) of ,late steel.ii. Lower turbine housing Brunner ,it liner The runner ,it will be fabricate) of

,late steel an) e>ui,,e) with a)e>uate baffles to )issi,ate the energ of /axi/u/continuous )ischarge of the jets un)er /axi/u/ hea).

iii. Accessories li(e runner re/o-al )oor /anhole ser-ice ,latfor/ runner han)ling cart etc.

Pit housing an) ,it liner will be asse/ble) on site b wel)ing an) e/be))e) in concrete.

Turine Co*er3

The turbine co-er will be a stationar re/o-able co/,onent flange) to the u,,er turbinehousing. t will ser-e as su,,ort an) casing for the turbine gui)e bearing an) shaft seal. Theco-er will ha-e a)e>uate strength an) rigi)it to trans/it safel all forces fro/ the gui)e

bearing to the runner ,it housing without un)ue stresses or )efor/ations.

The co-er has to su,,ort the weight of the runner an) turbine shaft when the turbine shaft is)isconnecte) fro/ the generator shaft. The lower ,art of the turbine co-er will be ,ro-i)e) withstiffeners an) fixe) on the runner ,it housing.

-+2+5+6 Turine >o*ernor

ach generating unit will be e>ui,,e) with a go-erning sste/ of the )igital /icro%,rocessingcontrolle) soli) state electro%h)raulic PD control for fast res,onse an) stable loa) control

,er/itting in)e,en)ent unit o,eration.

The go-ernors will ensure stable go-erning in ,arallel o,eration. n co/bine) o,eration thecan regulate the re>uire) ,ower e-en )uring fluctuation of the water le-el. n case of fre>uencfluctuation in the sste/ an auto/atic switch o-er to s,ee) control will be initiate) to stabili9ethe ,ower sste/ fre>uenc. The go-ernor is selecte) to ha-e sufficient ca,acit to su,,l theoil re>uire) for the gui)e -ane ser-o/otors to co/,letel o,en or close the gui)e -anes.

The go-ernor is ,ro-i)e) with the electronic s,ee) signal )e-ice for s,ee) )etection an)reference. t /ust often be ca,able of control b fre>uenc an) out,ut water le-el an) ,ower flow in the interconnections. n a))ition a si/,lifie) o,ening controlle) i.e /anual control willenable a continuation of the turbine o,eration if the s,ee) an) ,ower controller with theelectronic fee)%bac( )e-ice fail. This function shall be in)e,en)ent of the other go-ernor functions.

The go-ernor regulation )ata will be as follows

S,ee) rise )uring full loa) rejection Z +O





Pressure rise )uring full loa) rejection Z 20OTurbine closing ti/e 7ain nlet 5al-eB75 Z 0 secon)sDeflector closing ti/e Z 2. secon)s

!o99le closing ti/e Z 2 secon)s

-+2+5+- Pressure Oil !upply !ystem

The oil ,ressure unit for the go-ernor sste/ will be suitabl selecte) so that the unit hassufficient ca,acit to )ri-e the go-ernor an) actuate the oil%,ressure sste/. The go-ernor will

be locate) on the turbine floor near to the turbine.

The ,ressure oil su,,l sste/ of each unit consists of an oil su/, tan( ,ressure accu/ulator for go-ernor oil ser-o/otor /echanis/ two /otor )ri-en oil ,u/,s control -al-es ,i,ing

/onitoring sste/ an) other accessories.

The ,ressure re>uire/ent will )e,en) u,on the a/ount of energ re>uire) to /o-e the turbine

no99les )eflector inlet -al-e etc. #il ,ressure sste/ is arrange) as a single sste/ for thego-ernor an) inlet -al-e an) b%,ass -al-e actuators of the unit. The oil ,ressure sste/ willha-e sufficient ca,acit for o,erating the turbine ser-o/otors inlet -al-e an) other necessarsste/.

-+2+5+10 Turine :nlet Val*e

#ne inlet -al-e will be ,ro-i)e) for each ,ower unit. The -al-e will be of the s,herical t,e.For safet reason an) to re)uce the re>uire) ca,acit of the )rainage an) )ewatering sste/each -al-e will be e>ui,,e) with s/aller b%,ass -al-e for the filling ,roce)ure for the turbine)istributor ,i,ing. The b%,ass -al-es will be close) an) o,ene) b /eans of oil h)raulic

,ressure.

'olting flanges to the )istributor ,i,e an) ,enstoc( ,i,e will connect the /ain inlet -al-e. The-al-e will be o,en in balance) con)ition b oil ,ressure an) will be close) b counter weightfor safet reason. The nlet -al-e will o,erate un)er the following con)itions

Normal Operatin# Conditions3

5al-e o,ening will be initiate) after 0O ,ressure balancing between the u,strea/ an))ownstrea/ si)e is reache) whereas -al-e closing will ta(e ,lace un)er no%flow con)itionsBturbine no99les close)

)mer#en%y Operatin# Conditions3

n case failure of )eflector an) no99les ta(es ,lace the -al-e will close un)er the /axi/u/turbine flow con)ition an) the hea) at the turbine inlet in the shortest ti/e without causing the

,ressure in the ,enstoc( to rise abo-e its )esign -alue.

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-+2+5+11 !tation 9ater !ystem

The station water sste/s inclu)e the cooling water sste/ an) ser-ice an) )o/estic water

su,,l.

'+ Coolin# water supply system

Pro-ision of cooling water su,,l sste/ will be ,ro-i)e) for generator air cooler bearing oilcoolers etc. The C8 su,,l sste/ will consist of tailrace water ,u/,e) to the C8 su,,lhea)ers b base) /ounte) ,u/,s installe) in the ,owerhouse interior. Fro/ the hea)ersse,arate risers will con-e Cooling 8ater to the air coolers an) oil heat exchangers of thegenerating units through coarse an) fine filters an) will be )ischarge) to the tailrace.

The )rainage of the bac(wash water fro/ the auto/atic self cleaning strainers will )ischargeinto the tailrace.

Cooling water su,,l sste/ will consist of• Btwo cooling water su,,l ,u/,s base /ounte) co/,lete with electric

/otors.• Co/,lete ,i,ing sste/s for the C8 su,,l circuit.• Btwo auto/atic self cleaning strainers each co/,lete with electrical control

,anel with the ,ro-ision of /anual cleaning also.• Btwo )u,lex coarse strainers co/,lete with acessories.

+ !tation !er*i%e 9ater !ystem

A water storage tan( installe) at the suitable location of the ,owerhouse will ser-e as the sourcefor the ser-ice water. The source of ser-ice water is untreate) )e%san)e) water fro/ the tailrace or ,enstoc( ta,,ing or near b ri-er ta,,ing. The station ser-ice water a,,urtenancesconsists of hose bibbs an) water hoses.

Ser-ice water will be use) for wash )own of floor areas an) for general cleaning fire fighting.For )rin(ing ,ur,ose the necessar treat/ent of water will be re>uire).

-+2+5+12 8raina#es and 8ewaterin# !ystem

The water fro/ all coolers bearings lea(age fro/ turbine ,arts as well as all water see,agethrough the ,owerhouse walls an) joints in the station collecte) in gutters on each floor le-elshall be )ischarge) to the exterior of tailrace b gra-it through ,i,ing e/be))e) in the

,owerhouse )ownstrea/ wall.

The water in the ,enstoc( shall be )ischarge) to the tailrace b the )rain ,i,e. !ecessar -al-esan) ,i,e shall be ,ro-i)e).

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!o ,u/,s are re>uire) with this alternati-e as woul) be the case if the tail water le-el is higher than the )ischarge le-el.

-+2+5+1 >rease !upply !ystem

n recent ,ractice an oil%less bearing sste/ are use) so centrali9e) grease su,,l sste/ coul) be s(i,,e). f grease has to be use in certain ,arts a /anual han) grease ,u/, will be

reco//en)e). This results in a cost re)uction as well as sa-ing in s,aces.-+2+5+15 ra/es and @a%/in# !ystem

&enerating unit will be e>ui,,e) with a set of co/bine) ,neu/atic or h)raulic o,erate) bra(es an) jac(s. The bra(es an) jac(ing sste/ is re>uire) for bringing large /achines to restin a reasonabl short ti/e an) for /ini/i9ing wear on the bearing b ,rotracte) slow runningwhen shutting )own. Air bra(e or h)raulic oil ,ressure bra(e can be use. f air being use) itwill be su,,lie) b the co/,resse) air sste/. f air co/,ressor unit is not use) then h)raulicoil ,ressure bra(e will be use). The bra(e linings shall be of non%asbestos t,e.

The bra(e clin)er shall also ser-e h)raulic jac(s for lifting the turbine an) generator rotating ,arts as re>uire) for ins,ection an) re/o-al of the thrust bearing. For this ,ur,ose high ,ressure is re>uire) an) generall ,ro-i)e) b an external oil ,u/, unit.

-+2+5+1? Compressed 'ir !ystem

n the ,owerhouse co/,resse) air will be use) for generator air bra(es go-ernor sste/ser-ice air connections for air%)ri-en tools ,neu/aticall controlle) -al-es. This sste/ isco//on to both units an) co/,rises two air coole) co/,ressors one on )ut an) other stan)

b which fee) the /ain air recei-er tan(. The sste/ also consists of air filter air recei-er

/oisture tra,s ,ressure re)ucing -al-e control sste/ ,i,ing etc

Two t,es of co/,resse) air sste/ are use)

A. $i#h pressure air system

4igh ,ressure co/,resse) air will be use) for the go-ernor oil ,ressure sste/. A high ,ressureco/,resse) air su,,l sste/ co/,rising of two in)e,en)ent co/,ressors ser-ing all h)raulicunits will be installe). An auto/atic change o-er switch will select the /ain an) stan)%bco/,ressor. The co/,resse) air su,,l will be co/,lete in all res,ects containing all controlan) ,rotecti-e )e-ices li(e air safet -al-es after coolers /oisture se,arators shut%off -al-e

auto/atic /oisture )rain tra,s air )rers etc.

'. ow pressure air system

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Low ,ressure co/,resse) air is use) for station ser-ice ,ur,oses an) generator air bra(esste/. Low%,ressure sste/ is ta,,e) fro/ high ,ressure sste/ b ,ressure re)ucing -al-einto other low ,ressure tan(. As alternati-e se,arate low ,ressure co/,ressor unit sste/ can

be installe).

-+2+5+1. Oil $andlin# !ystem

The oil han)ling sste/ is utili9e) for storing conta/inate) lubricating oil fro/ the bearing

,ots of the generating units clean an) ,urifie) lubricating oil an) for filling the bearing ,otswith ,urifie) oil an) local treat/ent of oil at the go-ernor oil su/,s an) at bearing oil.

The ,ortable oil treat/ent unit is use) for local recon)itioning an) filtering of oil at the locationof go-ernor oil su/,s an) at each generating unit. The ,ortable unit inclu)es flexible oil hoseswith hose to ,i,e fittings.

-+2+5+14 'irConditionin# and Ventilation !ystem

The ,owerhouse air%con)itioning sste/ is use) to ,ro-i)e fresh filtere) an) coole) air to theControl roo/ office roo/s an) other i/,ortant areas. S,lit t,e air con)itioner with heat ,u/,

will be use) for such roo/s.

Fresh air su,,l -entilation sste/ is installe) in the ,ower house to )is,ose conta/inate) air an) to excess heat ,ro)uce) fro/ the o,eration of generating units. The -entilation sste/ will/ainl consist of necessar nu/bers of axial -entilation fans air su,,l )ucts with air )iffusers. The -arious ,owerhouse roo/s an) areas whose a/bient are not air con)itione) arecontinuousl su,,lie) with fresh filtere) outsi)e air li(e switch%gear roo/ office floor/achine hall generator floor turbine floor.

Air fro/ the toilets (itchen roo/ storage roo/ wor(sho,s batter roo/ )iesel generator roo/ is continuousl exhauste) out of the ,lant b se,arate wall /ounte) exhaust fans.

!u/ber of air exhaust fans of a,,ro,riate ca,acit will be installe).

-+2+5+16 Fire Prote%tion !ystem

A co/,lete set of fire ,rotection sste/ will be installe) in the ,owerhouse. The fire fightingsste/ will consist of

i. A water hose sste/ will be ,ro-i)e) at -arious location of the ,owerhouse. The sste/will consist of fire hose of a,,ro,riate si9e with a)justable s,ra no99le.

iii. Sufficient nu/ber of ,ortable )r che/icals an) C#2 clin)er will be ,ro-i)e) at-arious locations. The )r che/icals shoul) be )esigne) for fighting fires in soli)s oil





an) electrical e>ui,/ent. The C#2 units shoul) be )esigne) for fighting fires in oil an)electrical installations.

-+2+5+1- Me%hani%al 9or/shop

The /echanical wor(sho, will be e>ui,,e) with /achine tools an) )e-ices a,,ro,riate for the/aintenance an) re,air of all /echanical co/,onents an) /achining of the s/aller co/,onents of the /echanical electrical e>ui,/ent an) h)raulic steel structure. The wor( sho, will ser-ice the ,ower ,lant for /inor re,air an) /aintenance wor( at the site an) thiscoul) re)uce the outage ti/e.

The /echanical wor(sho, will be e>ui,,e) with following /ajor /achine tools an) )e-ices

• $ni-ersal lathe• Pillar%/ounte) )rilling /achine• Table )rilling /achine• Double%wheel rough%grin)ing /achine• Tool%grin)ing /achine• 7etal ,ower hac(saw /achine• 7anual bench%t,e shears• 7obile co/,ressor• lectric wel)ing /achine

• &as%wel)ing e>ui,/ent• 8or( benches• 4an)%)rilling /achines

#ne co/,lete set of basic tools inclu)ing ha//er chisels ,liers screw)ri-ers wrenchs,anners jac(s chain bloc(s etc. will be ,ro-i)e).

-+2+5+20 )le*ator

The le-ator will be ,ro-i)e) for 10 to12 ,ersons with :00 (g to 1000 (g ca,acit co/,letewith all accessories necessar for /eeting all a,,licable ,erfor/ance an) safet re>uire/ents.The s,ee) of the car will be 1 /?sec with le-eling accurac of //.

ts o,erational /o)e will be with 555F )ri-e control an) it will be )esigne) for nor/al an)e/ergenc ,ower con)itions. t will also be ,ro-i)e) with Auto/atic "escue De-ise BA"D.

An le-ator which will sto, at all floors starting fro/ Ser-ice 'a?Control "oo/ #,erating'a? LT "oo/ Cable S,rea) Area an) $tilit "oo/ will be ,ro-i)e).

-+2+5+21 Powerhouse O*erhead Tra*elin# Crane

For unloa)ing an) erection of e>ui,/ent in the ,owerhouse an o-erhea) tra-eling crane withsingle bea/ will be ,ro-i)e). The crane will be electricall )ri-en an) furnishe) with a singletra-eling trolle for the /ain hoist. The o,eration range of the crane will ensure erection of all





/ajor e>ui,/ent ,arts inclu)ing the turbine inlet -al-e. The ca,acit of the /ain hoist is)eter/ine) b the weight of the hea-iest ,art i.e. generator. The crane will be e>ui,,e) withtwo s,ee)s one for longitu)inal tra-el an) the other for cross tra-els.

The crane will be o,erate) s/oothl e-en at the /ost a)-erse con)ition. The crane will becontrolle) b re/ote or fro/ a cabin arrange) on the crane bri)ge.

Following are the ,rinci,al characteristics of the o-erhea) tra-eling crane

#-erhea) tra-eling crane 'ri)ge t,e wel)e) constructionCrane S,an 1*. /7ini/u/ /ain hoist ca,acit tons

Bor hea-iest ,art to be han)le )uringo-erhauling

Auxiliar 4oist Ca,acit 10 tonsLength of runwa +* /

-+2+? Power >eneration at a#ar Khola

The following sections )eal with the ,owerhouse electro/echanical e>ui,/ent for ,ower generation at 'agar =hola.

-+2+?+1 Plant Capa%ity

The installe) ca,acit of the ,roject is calculate) to be *2+ (8 at the generator ter/inal. The installe)ca,acit is base) on the results of the o,ti/i9ation stu)ies an) is an a,,roxi/ate -alue. De,en)ing onthe efficienc of the su,,lie) /achiner the calculate) out,ut ca,acit coul) show /inor )ifferences.

-+2+?+2 Numer o7 "nits and "nit Capa%ity

Se-eral ele/ents affect the nu/ber of units chosen for a h)raulic ,ower ,lant such as thecharacteristic of the interconnecting sste/ the /aintenance /etho)s an) the total cost in-este) in the

,roject. As single unit is not ,referre) )ue to fact that generation loss will occur in ti/e of the unit brea(%)own or /aintenance as well as )uring low )ischarge ,erio) ,artial loa) o,eration of generatingunit is not ,referre). The selection of two units is /ore suitable than a single unit for flexibilit of

o,eration an) /aintenance sche)ule of units. Therefore two units of generator E turbine of e>ualca,acit ha-e been selecte).

'ase) on the o,ti/u/ ca,acit of *2+ (8 an) the nu/ber of units of two the rate) out,ut of each unitof the ,roject has been selecte) at 12 (8 with a rate) net hea) of 12.< / an) a rate) flow of 1.

/*?sec.

n calculating the re>uire) turbine an) generator ,ower out,uts for this stu) the following -alues of efficienc are assu/e) base) on the ex,erience )ata a-ailable.

Turbine ;O&enerator <*O

Tundi Power Company "! %ea(ii,ity &tudy




-+2+?+ !ele%tion o7 Turine Type

n ,ractice -arious ,roce)ures are use) for the selection of the t,e of turbines. Fro/ $S'" turbine

selection gra,h of hea) -erses )ischarge the selection of a hori9ontal axis Francis turbine constitutes agoo) o,tion consi)ering eas /aintenance in co/,arison to =a,lan turbine with a rate) hea) of 12.< /an) )ischarge of 1. /*?sec for the ,roject.

-+2+?+5 !pe%i7i% !peed and !yn%hronus !peed

The calculate) s,ecific s,ee) li/it for the gi-en rate) hea) is *:.< (8%/. The corres,on)ing turbines,ee) li/it is 11;1 r,/ for Francis turbine. The snchronous s,ee) /ust be selecte) base) on thenu/ber of the generator ,oles an) the networ( fre>uenc as well as turbine setting with res,ect to tailwater le-el for hori9ontal shaft unit nor/al ,ractice is to set turbine abo-e tail water le-el. 'ase) on theabo-e criteria the rate) snchronous s,ee) is 1000 r,/ which is best a,,licable s,ee) for the turbines,ee). So the corres,on)ing actual s,ecific s,ee) of the turbine at rate) hea) is *<.: (8%/.

-+2+?+? 8es%ription o7 Turines

The turbines will be of the hori9ontal shaft single runner Francis t,e with s,iral case an) elbow t,e)raft tube. The turbine will be e>ui,,e) with wic(et gates for regulation of ,ower out,ut an) control of s,ee) for starting snchroni9ing an) shut )own.

The runner will be )irectl cou,le) to the A.C. &enerators shaft. The turbine will be e>ui,,e) withturbine housing which will gui)e the ,ressure release) water fro/ the runner to the tailrace safel.

All turbine instru/entation such as unit control boar)s an) go-ernor control cabinets will be locate)close to the rele-ant units on the turbine floor. This is a)-antageous for co//issioning ser-ice an)/aintenance.

-+2+?+. Prin%ipal Chara%teristi%s

The ,rinci,al characteristics of the selecte) hori9ontal shaft t,e Francis turbines are as follows

!u/ber of turbine Two B2Shaft arrange/ent 4ori9ontalnstalle) ca,acit for each unit 12 (8Turbine fficienc ;O"ate) )ischarge for each unit 1. /*?s&ross hea) 1* /"ate) net hea) 12.< /"ate) s,ee) 1000 r,/S,ecific S,ee) *<.: (8%/"unwa s,ee) 1<; r,/"unner Discharge Dia/eter 0+ //

!or/al water le-el at foreba L 1:. /aslTailrace water L 1+. /asl

"unner center line L 1.: /asl

Penstoc( or s,iral casing center line L 1+.< /aslTurbine center line to in-ert of )raft tube 2.+ /Draft tube exit )ia/eter 1.01 /

Tundi Power Company "# %ea(ii,ity &tudy




-+2+?+4 8es%ription o7 the Main Parts

The /ain ,arts of the turbine are )escribe) below in brief.

Runner

The turbine will be a single runner attache) )irectl to the flange at the en) of the generator shaft. The/etho) of attach/ent will be )esigne) to ,er/it con-enient re/o-al of the runner. To a-oi) ca-itationan) erosion the runners will be /a)e of integrall cast or wel)e) stainless steel with a,,ro,riate blen)of chro/iu/ an) nic(el 1*O Cr an) +O !i well suite) for site re,air wel)ing. All runners are )esigne)to be interchangeable.

The runner will be )esigne) an) constructe) to safel withstan) the stresses )ue to o,eration at runwas,ee) an) un)er the /ost se-ere con)itions. The h)raulic surfaces of runner will be carefull groun)e)an) finishe) s/oothl.

'olte) connection will be ,ro-i)e) for attaching the runner to the shaft. The bolts shall be loc(e) in ,osition to ,re-ent loosening )uring o,eration.

!piral Casin# and !tay Rin#

The s,iral case will be /a)e of high >ualit steel ,late with wel)e) ra)ial joint )i-i)e) into sufficientnu/ber of sections. The s,iral case shall safel carr the /axi/u/ internal ,ressure resulting fro//axi/u/ hea) an) ,ressure rise )ue to surge an) water ha//er. A suitable si9e of /anhole will

,ro-i)e access to the s,iral casing fro/ the turbine floor. The sta ring shall be /a)e of hea- wel)e)

steel ,late an) wel)e) into integral ,art with s,iral case. The turbine )istributor will also e>ui,,e) withthe turbine u,strea/ si)e co-er an) )ownstrea/ si)e co-er.

>uide Vanes

The gui)e -ane will be /a)e of chro/iu/ an) nic(el 1*O Cr an) +O !i an) thus highl resistant toca-itation san) erosion an) shall be rigi) enough to withstan) )eflection. The gui)e -ane will be

,ro-i)e) with oil less self%lubricating bearings for turbine si)e co-er an) for )raft tube si)e co-er.

8ra7t Tue

Draft tube will be /a)e of wel)e) steel ,late an) /a)e of steel liner. The )raft tube shall be )is/antableto enable an eas re,lace of the runner. nterior of the )raft tube shall be s/ooth an) exterior shall beribbe) for reinforce/ent an) sufficient nu/ber of wel)e) anchors to establish fir/ gri, to surroun)ingconcrete. A )raft tube will be e>ui,,e) with two hinge )oor /anholes an) accessible all aroun).

!ha7t

f se,arate turbine shaft is re>uire) to cou,le with generator shaft the shaft will be /a)e of ,ro,erlheat treate) forge) steel. t will be )esigne) to o,erate safel at an s,ee) u, to the /axi/u/ runwas,ee) without )etri/ental -ibration or )istortion.

>uide earin#

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The turbine will be e>ui,,e) with a self lubricating oil t,e gui)e bearing. The bearing will consist of su,,ort or housing an) a re/o-able bearing sheet. The gui)e bearing will be of self lubricate) an) water coole) an) co/,lete with oil reser-oir an) water cooling coil.

-+2+?+6 Turine >o*ernor

ach generating unit will be e>ui,,e) with a go-erning sste/ of the )igital /icro%,rocessingcontrolle) soli) state electro%h)raulic PD control for fast res,onse an) stable loa) control ,er/ittingin)e,en)ent unit o,eration.

The go-ernors will ensure stable go-erning in ,arallel o,eration. n co/bine) o,eration the canregulate the re>uire) ,ower e-en )uring fluctuation of the water le-el. n case of fre>uenc fluctuationin the sste/ an auto/atic switch o-er to s,ee) control will be initiate) to stabili9e the ,ower sste/fre>uenc. The go-ernor is selecte) to ha-e sufficient ca,acit to su,,l the oil re>uire) for the gui)e-ane ser-o/otors to co/,letel o,en or close the gui)e -anes.

The go-ernor is ,ro-i)e) with the electronic s,ee) signal )e-ice for s,ee) )etection an) reference. t/ust often be ca,able of control b fre>uenc an) out,ut water le-el an) ,ower flow in theinterconnections. n a))ition a si/,lifie) o,ening controlle) i.e /anual control will enable a

continuation of the turbine o,eration if the s,ee) an) ,ower controller with the electronic fee)%bac( )e-ice fail. This function shall be in)e,en)ent of the other go-ernor functions.

The go-ernor regulation )ata will be as follows

S,ee) rise )uring full loa) rejection Z +O

Pressure rise )uring full loa) rejection Z *O7ain nlet 5al-eB75 closing ti/e Z 0 secon)s&ui)e -ane closing ti/e Z10 secon)s

-+2+?+- Pressure Oil !upply !ystem

The oil ,ressure unit for the go-ernor sste/ will be suitabl selecte) so that the unit has sufficientca,acit to )ri-e the go-ernor an) actuate the oil%,ressure sste/. The go-ernor will be locate) on theturbine floor near to the turbine.

The ,ressure oil su,,l sste/ of each unit consists of an oil su/, tan( ,ressure accu/ulator for go-ernor oil ser-o/otor /echanis/ two /otor )ri-en oil ,u/,s control -al-es ,i,ing /onitoringsste/ an) other accessories.

The ,ressure re>uire/ent will )e,en) u,on the a/ount of energ re>uire) to /o-e the turbineregulating sste/ i.e. gui)e -anes inlet -al-e etc. #il ,ressure sste/ is arrange) as a single sste/ for the go-ernor an) inlet -al-e an) b%,ass -al-e actuators of the unit. The oil ,ressure sste/ will ha-esufficient ca,acit for o,erating the turbine ser-o/otors inlet -al-e an) other necessar sste/.

-+2+?+10 Turine :nlet Val*e

#ne inlet -al-e will be ,ro-i)e) for each ,ower unit. The -al-e will be of the 'utterfl t,e. For safetreason each -al-e will be e>ui,,e) with s/aller b%,ass -al-e for the filling ,roce)ure for the turbine

)istributor ,i,ing. The b%,ass -al-es will close an) o,en b /eans of oil h)raulic ,ressure.





'olting flanges to the )istributor ,i,e an) ,enstoc( ,i,e will connect the /ain inlet -al-e. The -al-ewill be o,en in balance) con)ition b oil ,ressure an) will be close) b counter weight for safetreason. The nlet -al-e will o,erate un)er the following con)itions

Normal Operatin# Conditions

5al-e o,ening will be initiate) after 0O ,ressure balancing between the u,strea/ an) )ownstrea/ si)eis reache) whereas -al-e closing will ta(e ,lace un)er no%flow con)itions Bturbine gui)e -anes close)

)mer#en%y Operatin# Conditions

n case failure of gui)e -anes to wor( the -al-e will close un)er the /axi/u/ turbine flow an) hea) atthe turbine inlet in the shortest ti/e without causing the ,ressure in the ,enstoc( to rise abo-e its )esign-alue.

-+2+?+11 !tation 9ater !ystem

The station water sste/s inclu)e the cooling water sste/ an) ser-ice an) )o/estic water su,,l.

'+ Coolin# water supply system

Pro-ision of cooling water su,,l sste/ will be ,ro-i)e) for generator air cooler bearing oil coolersetc. f the water >ualit is goo) free fro/ silt an) soil cooling water sste/ will be ta,e) fro/

,enstoc(s just u,strea/ of the inlet -al-e. The water fro/ an in)i-i)ual ta,,ing is firstl ,ressurere)uce) an) then ,asse) through a coarse /esh filter one on )ut an) one stan)b an) then through afine rotar strainer one on )ut an) one stan)b an) ulti/atel to the heat exchangers.

+ !tation !er*i%e 9ater !ystem

A water storage tan( installe) at the suitable location of the ,owerhouse will ser-e as the source for theser-ice water. The source of ser-ice water is untreate) )e%san)e) water fro/ the tail race or ,enstoc( ta,,ing or near b ri-er ta,,ing. The station ser-ice water a,,urtenances consist of hose bibbs an)water hoses.

Ser-ice water will be use) for wash )own of floor areas an) for general cleaning fire fighting. For )rin(ing ,ur,ose the necessar treat/ent of water will be re>uire).

-+2+?+12 8raina#es and 8ewaterin# !ystem

The water fro/ all the coolers bearing etc. will be )ischarge) to tail race through e/be))e) ,i,ing.The water below tailrace le-el will be collecte) in the su/, ,it b o,ening )rain -al-e connecte) to thelowest ,oint through the e/be))e) stainless steel ,i,ing locate) in the )e%watering su/,. Collecte)water will be then )ischarge) to tailrace b ,u/,ing.

The lea(age water fro/ the turbine shaft seal an) gate control /echanis/ an) walls of ,owerhouse buil)ing will be )ischarge) abo-e floo) le-el of tail%race fro/ there the water will flow b gra-it intothe tailrace if gra-it flow is not ,ossible for )ischarging water will be collecte) in the )rainage su/,.The sub/ersible t,e )rainage ,u/,s are use to ,u/,e) it through e/be))e) ,i,ing to the tail%race.The water shall be )ischarge) abo-e floo) le-el of tail%race fro/ there the water will flow b gra-it

into the tailrace.The water in the ,enstoc( shall be )ischarge) to the tailrace b the )rain ,i,e. !ecessar -al-es an)

,i,e shall be ,ro-i)e).





The sste/ shall be )esigne) so that the ex,ose) ,i,ing can be rea)il )is/antle) for cleaning.

-+2+?+1 >rease !upply !ystem

n recent ,ractice an oil%less bearing sste/ is use) so that the centrali9e) grease su,,l sste/ can bes(i,,e). f grease has to be use) in certain ,arts a /anual han) grease ,u/, will be reco//en)e). Thisresults in a cost re)uction as well as sa-ing in s,aces.

-+2+?+15 ra/es and @a%/in# !ystem

&enerating unit will be e>ui,,e) with a set of co/bine) ,neu/atic or h)raulic o,erate) bra(es an) jac(s. The bra(es an) jac(ing sste/ is re>uire) for bringing large /achines to rest in a reasonablshort ti/e an) for /ini/i9ing wear on the bearing b ,rotracte) slow running when shutting )own. Air

bra(e or h)raulic oil ,ressure bra(e can be use. f air is being use) it will be su,,lie) b the

co/,resse) air sste/. f air co/,ressor unit is not use) then h)raulic oil ,ressure bra(e will be use).The bra(e linings shall be of non%asbestos t,e.

The bra(e clin)er shall also ser-e h)raulic jac(s for lifting the turbine an) generator rotating ,arts asre>uire) for ins,ection an) re/o-al of the thrust bearing. For this ,ur,ose high ,ressure is re>uire)an) generall ,ro-i)e) b an external oil ,u/, unit.

-+2+?+1? Compressed 'ir !ystem

n the ,owerhouse co/,resse) air will be use) for generator air bra(es go-ernor sste/ ser-ice air connections for air%)ri-en tools ,neu/aticall controlle) -al-es. This sste/ is co//on to both unitsan) co/,rises two air coole) co/,ressors one on )ut an) other stan) b which fee) the /ain air recei-er tan(. The sste/ also consists of air filter air recei-er /oisture tra,s ,ressure re)ucing -al-econtrol sste/ ,i,ing etc

Two t,es of co/,resse) air sste/ are use)

A. 4igh ,ressure air sste/ % is use) for go-ernor oil ,ressure sste/'. Low ,ressure air sste/ % is use) for station ser-ice ,ur,oses an) generator air bra(e sste/.

Low%,ressure sste/ is ta,,e) fro/ high ,ressure sste/ b ,ressure re)ucing -al-e into other low ,ressure tan(. As alternati-e se,arate low ,ressure co/,ressor unit sste/ can be installe).

-+2+?+1. Oil $andlin# !ystem

The oil han)ling sste/ is utili9e) for storing conta/inate) lubricating oil fro/ the bearing ,ots of thegenerating units clean an) ,urifie) lubricating oil an) for filling the bearing ,ots with ,urifie) oil an)local treat/ent of oil at the go-ernor oil su/,s an) at bearing oil.

#ne ,ortable oil treat/ent ,lant is furnishe) installe) on a ,latfor/ truc(. The oil store) in the )irt%oiltan( is filtere) through the ,er/anent oil treat/ent ,lant an) store) in the clean oil tan(. The ,ortable

oil treat/ent ,lant is use) for local recon)itioning an) filtering of oil at the location of go-ernor oilsu/,s an) at each generating unit. The ,ortable unit inclu)es flexible oil hoses with hose to ,i,efittings.

Tundi Power Company #! %ea(ii,ity &tudy




-+2+?+14 'irConditionin# and Ventilation !ystem

The ,owerhouse air%con)itioning sste/ is use) to ,ro-i)e fresh filtere) an) coole) air to the Control

roo/ office roo/s an) other i/,ortant areas. Pac(age) t,e air con)itioner will be use) for suchroo/s. t will consist of ,ac(age) t,e in)oor air%con)itioners unit on the roo/s unit of the air coole)

con)ensing units on the exterior or roof an) refrigerant ,i,e.

Fresh air su,,l -entilation sste/ is installe) in the ,ower house to )is,ose conta/inate) air an) toexcess heat ,ro)uce) fro/ the o,eration of generating units. The -entilation sste/ will /ainl consistof necessar nu/bers of axial -entilation fans air su,,l )ucts with air )iffusers. The -arious

,owerhouse roo/s an) areas whose a/bient are not air con)itione) are continuousl su,,lie) withfresh filtere) outsi)e air li(e switch%gear roo/ office floor /achine hall generator floor turbine floor)raft tube floor.

-+2+?+16 Fire Prote%tion !ystem

The fire fighting sste/ will consist of water )eluge an) s,rin(le sste/ an) ,ortable )r che/icals an)C#2 clin)ers.

A water hose sste/ will be ,ro-i)e) at -arious locations of the ,owerhouse. The sste/ will consist of a fire hose of a,,ro,riate si9e with a)justable s,ra no99le.

Sufficient nu/ber of ,ortable )r che/icals an) C#2 clin)er will be ,ro-i)e) at -arious locations. The

)r che/icals shoul) be )esigne) for fighting fires in soli)s oil an) electrical e>ui,/ent. The C#2 unitsshoul) be )esigne) for fighting fires in oil an) electrical installations.

-+2+?+1- Powerhouse $oistin# !ystem

For unloa)ing an) erection of e>ui,/ent in the ,owerhouse ton ca,acit han) ,ulling bloc( will beuse) for hoisting ,ro,ose b using tri,o) stan).

-+2+. Powerhouse )le%tri%al )Guipment

-+2+.+1 >enerator, )(%itation and 'n%illaries

-+2+.+1+1 8esi#n Criteria

The unit rating of the turbine%generator has been selecte) base) on the criterion that the/ini/u/ two units an) ca,acit of each unit )oes not excee) 10O of the total !AHsforecaste) loa) of the sste/. This assu/,tion is base) on the following consi)eration

a. to li/it the trans,ortation si9es an) weightsY b. to /ini/i9e the ,ower shortage )uring /aintenance or force) outage of a unitYc. to ,ro-i)e sufficient flexibilit )uring o,erationY). to be able to /aintain the sste/ stabilit )uring the tri,,ing of a unit.

'ase) on o,ti/u/ ca,acit of +;. 78 an) abo-e /entione) criteria the generating unit rate)out,ut has been selecte) at 2+.2 78.

Tundi Power Company ## %ea(ii,ity &tudy




The generator in the surface ,owerhouse will be a snchronous -ertical shaft unit cou,le) to itsassociate) -ertical Pelton turbine. The rating of generator will be 2120 (8 which will slightlexcee) the turbine out,ut un)er /ean reser-oir le-el an) hea) con)itions. For the ,ur,ose of

this stu) the generator rate) -oltage is selecte) to be 11 (5 0 49 an) at 0.; ,ower factor.The s,ee) will /atch the turbine snchronous s,ee) which is +2;.: "P7. t has beenassu/e) that the ,ur,ose of these stu)ies that snchronous con)enser o,eration will not bere>uire).

The rotor an) stator win)ings will be insulate) at class F howe-er the te/,erature rise will beli/ite) to ;0 )egree Celsius o-er a /axi/u/ cooling air te/,erature of +0 )egree Celsius.

The generator will be totall enclose) air an) water coole) with air to water heat exchangerslocate) in the generator ,it. The generator fire ,rotection will be ,ro-i)e) b a C# 2 )eluge

sste/. The acti-ation of the C#2 fire ,rotection sste/ will be con)itional to the o,eration of the fla/e or s/o(e )etectors in the generator ,it co/bine) with the o,eration of the generator )ifferential ,rotection.

The generator will be e>ui,,e) with a set of co/bine) ,neu/atic or h)raulic o,erate) bra(esan) jac(s.

For the fast res,onse to assist with the sste/ reliabilit flexibilit an) /aintainabilit of the ,ower sste/ )uring )isturbances it is ,ro,ose) to ha-e the generator e>ui,,e) with staticexcitation sste/ an) ,ower sste/ stabili9er.

The ,reli/inar /ain ,ara/eters of the generators are su//ari9e) in the following table

Tale -6 Preliminary Parameters o7 the >enerators

Parameters Value

!u/ber of units 2"ating 2+20 (8 hori9ontal axisPower factor 0.;

!or/al ca,abilit 2;2<.+1 (5A Bstan)ar) si9e

Cooling 8ater ?Air CoolingSnchronouss,ee)

+2;.: r?/in

!u/ber of ,oles 1+Fre>uenc 0 49"ate) -oltage 11 (5fficienc 0.<

-+2+.+1+2 )(%itation !ystem

The selecte) excitation for the generator is a Static xcitation sste/. The re>uire) ).c.

excitation is ,ro-i)e) through a bri)ge rectifier an) filtering arrange/ent. Auto/atic 5oltage"egulator BA5" will be use) for the generator.

Tundi Power Company 1$1 %ea(ii,ity &tudy




-+2+.+1+ !wit%h#ear and 'sso%iated )Guipment

The no/inal current rating of the connection of the each generator ter/inals to the switchgear

at 11 (5 is 1+<:.+ A. To /eet this current rating it is ,ossible an) the suitable solution to use ,arallel 12 (5 MLP insulate) cables without affecting the reliabilit of the installation. The bus will connect the generator ter/inals to11 (5 generator switchgear which will be locate) inthe generator floor. The ta,s connection fro/ /ain bus to the xciter will be through7arshalling cubicle B7C a)jacent to the xcitation Transfor/er of each unit. The excitationtransfor/er an) the cubicle will be installe) at the generator floor next to the 7C.

The neutral si)e of the generator will connect the generator neutral ter/inals to generator neutral groun)ing cubicle through a high -oltage ,ower cable.

The connections between 11 (5 switchgears for ,ower transfor/ers locate) in the generator

floor an) the /ain ste,%u, transfor/er locate) at out)oor switchar) is also selecte) b 12 (5cables. n or)er to /eet this current re>uire/ent single core two ,arallel co,,er con)uctor ,ower cables are enough for each ,ower transfor/er which is co//erciall a-ailable.

The Auxiliar Ser-ice Transfor/er 12 (5 /ain Switchgears an) will be locate) on thegenerator floor an) 1*2 (5 control ,anels will be locate) in the control roo/. Si/ilarl Localsu,,l transfor/er L5 switchgears an) the /otor control centres B7CC will be locate) at theturbine floor.

The outgoing fee)ers of the 11 (5 switchgears will be aligne) with /ain switchgear locate) atgenerator floor.

The ,owerhouse sche/e is as shown on the single line )iagra/ in Drawing !o. $"%P4%01.

-+2+.+2 Main Power Trans7ormers

ach generating unit will be se,aratel connecte) to its in)i-i)ual ,ower transfor/er. ach of the unit ,ower transfor/ers will be three ,hase oil i//erse) force) oil cooling sste/. Theoutgoing 11 (5 switchgear bus of each unit will be connecte) to three%,hase ste,%u, ,ower

transfor/ers which will be locate) at out)oor switchar). #n the low -oltage si)e thetransfor/er will be e>ui,,e) with flange for cable connections an) on the high -oltage si)e 1*2(5 bushings will be ,ro-i)e).

Connections of high -oltage ter/inals of the transfor/ers switchgear an) ,rotectione>ui,/ent locate) at the switchar) will be /a)e b ACS" bear con)uctors. The neutral of the45 si)e of the transfor/er will be soli)l groun)e).

The three ,hase *0000 (5A 0 49 ,ower transfor/ers will ste,%u, the 11 (5 of generator -oltage to 1*2 (5. This transfor/er rating is stan)ar) si9e an) consistent to the rating of thegenerators. Although the -ariation in -oltage can be acco/,lishe) b the -oltage a)just/ent of the generator it is reco//en)e) that an off%loa) ta,%changer will be ,ro-i)e) to co/,ensatefor changes in the sste/ o,erating characteristics throughout the life of the ,lant. The





,ro,ose) ta, range is X?% 2 x 2.O. The cooling shall be #!A!. This cooling /etho) will notre>uire fans which eli/inate fans controls an) /eets the o,erating con)itions.

The transfor/er ,ara/eters are su//ari9e) as follows

Tale -- Preliminary Parameters 7or the Trans7ormers

"ating *0000 (5A Bstan)ar)Cooling #!A!Pri/ar -oltage 11 (5Secon)ar -oltage 1*2 (55ector grou, D6n%11 BSoli)l groun)e) neutralFre>uenc 0 49Ta,s %OY %2.OY 0Y X2.OY XO on the 1*2 (5 win)ings/,e)ance less than 12 O

fficienc << O

-+2+4 Powerhouse )le%tri%al 'u(iliaries

-+2+4+1 'C Powerhouse 'u(iliaries

AC ,owerhouse auxiliaries fall into two /ain grou,s essential ser-ices auxiliaries an)co//on ser-ices auxiliaries. These are )iscusse) se,aratel below.

-+2+4+1+1 )ssential 'C 'u(iliaries+

ssential unit auxiliaries are those without which the unit cannot be (e,t in o,eration na/elgo-ernor an) transfor/er oil ,u/,s the cooling water ,u/,s the lubrication oil ,u/,s an)the xcitation sste/s. For the ,ower house the essential ser-ices )ouble en)e) switchgear su,,l the ,ower house essential ser-ices. The ssential ser-ices switchgear is fe) fro/ twoalternate sources na/el fro/ auxiliar ser-ice or as )escrie) below in section Bb or fro/ thee/ergenc )iesel generator as )escribe) in following section. The two inco/ing circuit

brea(ers are interloc(e) to ,re-ent ina)-ertent ,aralleling of two alternate sources.

-+2+4+1+2 Common !er*i%es 'C 'u(iliaries+

The co//on ser-ices auxiliaries can be )i-i)e) into three sub%grou,s as follows

• Nonessential %ommon ser*i%e au(iliaries are those which are less affecte) b the loss of su,,l o-er a short ,erio) of ti/e. These auxiliaries inclu)e co//unication e>ui,/ent an)lighting. These loa)s will be fe) -ia the 7otor Control Centres B7CC which in turn fe)fro/ the Co//on Auxiliar Ser-ices Switchgear.

• Operational %ommon ser*i%es au(iliaries are those without which o-er a longer ,erio) of

ti/e the ,owerhouse will cease to be o,erational such as )ewatering ,u/,s switchgear an) go-ernor air co/,ressors Bif re>uire) an) batter chargers. These loa)s will benor/all fe) through the +00?2*05 7otor Control Centres B7CC.





• Maintenan%e %ommon ser*i%es au(iliaries can be )is,ense) with occasionall. T,icalones are station cranes the /ajorit of air con)itioning co/,resse) air for tools an) oilfiltering e>ui,/ent. These loa)s will be fe) -ia the Co//on Auxiliar Ser-ices

Switchgear.

The selecte) sche/e for the auxiliar ser-ices is shown in the Single Line Diagra/ of

Auxiliar Ser-ices BDwg no. $"%L%02 is base) on the following criteria 1. Failure of Auxiliar Ser-ices transfor/er or L5 /ain fee)er bus or circuit brea(er shoul)

not cause the failure of the unit auxiliar sste/Y

2. 7aintenance on Auxiliar Ser-ices Switchgear will be ,ossible without interru,tion to

essential auxiliar ser-icesY

*. Phsical laout of the ,owerhouse shoul) be ta(en into account so that the suggeste)sche/e is both ,ractical an) cost effecti-e

'ase) on the abo-e criteria se-eral alternati-e sources of su,,l are ,ro-i)e). The sources an)their interconnections to the -arious le-el of su,,l are )iscusse) below

• The ,ri/ar of the )r t,e auxiliar transfor/ers is connecte) to the 11 (5 switchgear an) the secon)ar to the +00?2*0 5 auxiliar ser-ices switchgear. The inco/ing circuit

brea(ers of the Auxiliar Ser-ices Switchgear are interloc(e) thus ,re-enting the

• ina)-ertent ,aralleling of two units on the low -oltage si)e. The outgoing circuit brea(er for the L5 switchgear fee)s the 7CCs of unit an) ,owerhouse co//onauxiliaries.

• The e/ergenc ser-ices switchgear is nor/all fe) fro/ the +00?2*05 Low 5oltageCo//on Auxiliar Ser-ice Switchgear. The auto/atic transfer is /a)e to thee/ergenc )iesel generator u,on loss of the /ain su,,l -oltage.

• n case of the /ain su,,l failure the )iesel e/ergenc generator will auto/aticallstart an) fee) the ssential Ser-ices Switchgear. n such an e-entualit the circuit

brea(er to the Auxiliar Ser-ices Switchgear will o,en to ,re-ent o-erloa)ing of )ieselgenerating unit.

• A )iesel generator si9e) to fee) the essential loa)s will ,ro-i)e station e/ergenc ,ower su,,l in the e-ent of una-ailabilit of the generating units an) an o-erall sste/outage.

• #ne of the fee)ers of the co//on auxiliar ser-ices switchgear will fee) the outsi)e

switchar) the tailrace an) hea)wor(s auxiliaries the lighting aroun) the ,owerhouseentrance.

Tundi Power Company 1$! %ea(ii,ity &tudy




-+2+4+2 8C Powerhouse 'u(iliaries

For the ut/ost reliabilit the Control Protection Alar/ an) Tele/etering e>ui,/ent will be

fe) fro/ a DC su,,l. The DC su,,l is ,ro-i)e) b /ain an) re)un)ant batter sets an) eachset su,,lie) b )ouble batter chargers. The basic conce,t being that the failure of a single DCsu,,l sste/ shoul) not ,ut into jeo,ar) the o,eration of the control an) ,rotection relasste/ an) conse>uentl the ,owerhouse. The e/ergenc lighting can be DC autono/ousin)i-i)ual units or with $PS Buninterru,table ,ower su,,l. For the ,ur,ose of this stu) aDC batter su,,lie) e/ergenc lighting has been selecte). The 110 5 DC ,anels will belocate) in the batter charger next to the batter roo/. 'atter an) charger si9es will be

)eter/ine) )uring subse>uent )esign ,hase. The batteries for the control ,rotection an)

e/ergenc lighting will be 110 5 DC an) those for co//unication sste/s will be at 2+ 5 or +; 5 DC.

An uninterru,tible ,ower su,,l B$PS will also ,ro-i)e the AC su,,l )eri-e) fro/ 110 5 )csu,,lie) static in-erters for the SCADA sste/.

-+2+4+ )mer#en%y 8iesel >enerator

t is ,ro,ose) that one e/ergenc generator set be installe) in the )iesel generator buil)ing to ,ro-i)e an e/ergenc source of ,ower in the e-ent of a sste/ an) ,ower outage. The )ieselgenerator will be locate) at the switchar). The )iesel generating set alternati-e was a)o,te) as

the ,referre) stan)b ,ower su,,l on the basis of cost ta(ing into consi)eration its antici,ate)li/ite) usage an) guarantee) a-ailabilit. Since there is onl one hea)race tunnel if this is)raine) no water woul) be a-ailable for generation ,ur,ose.

The )iesel generator woul) be of a)e>uate rating to su,,l sufficient ,ower to enable the blac( starting of one unit an) the o,eration of )rainage ,u/,s a go-ernor oil ,u/, a bearing oil

,u/, an air co/,ressor for go-ernor sste/ an) fee) the batter chargers. The stan)bgenerator ca,acit is esti/ate) to be about 20 (8 at 0.; ,ower factor. The ter/inal -oltage of the generator will be +00?2*05.

The ,ro,ose) sche/e shown in Dwg no. $"%L%02 is )esigne) to ,ro-i)e /axi/u/ flexibilitin /aintaining a secure an) reliable auxiliar su,,l sste/.

The /ain )istribution sste/ for auxiliar electrical su,,lies will be as follows

• +00?2*0 5 ac * ,hase + wire 0 49 with earthe) neutral for station lighting an) ,ower auxiliariesY

• 110 5 )c unearthe) for unit control ,rotection /etering an) for e/ergenc lightingY• 110 5 ac 0 49 B)eri-e) fro/ 110 5 )c su,,lie) static in-erters for e>ui,/ent which

re>uires a reliable ac su,,lY

• 2+ 5 or +; 5 )c for co//unications.

Tundi Power Company 1$# %ea(ii,ity &tudy




-+2+4+5 Control and Prote%tion

A control roo/ for the ,owerhouse the /e)iu/ -oltage switchgear an) the associate) wor(s

will be locate) within the ,owerhouse. t will be ,ossible to control the units an) the auxiliarsste/ fro/ this control roo/.

The unit electronic go-ernors an) the unit control ,anels will be arrange) on the generator floor. 'oth /anual an) auto/atic control will be ,ro-i)e). For the testing of the unit )uringco//issioning an) /aintenance it will be ,ossible to control a unit in either auto/atic or /anual /o)e fro/ the ,anel. 4owe-er unit snchroni9ation will not be ,er/itte) fro/ the unitcontrol ,anel. 8hen the unit is rea) for snchroni9ing the auto/atic or /anualsnchroni9ation will be ,ossible onl fro/ the Control "oo/.

The ,owerhouse an) switching e>ui,/ent will be controlle) fro/ the control )es( locate) in

the Control "oo/. The station control console with its own control an) /onitoring instru/ents

the snchroni9er the station annunciators the /etering ,anels the ,rotecti-e rela ,anels an)the te/,erature recor)ers will be locate) in the ,owerhouse Control "oo/. The unit ,rotectionwill inclu)e the following rela functions generator earth fault o-er -oltage un)er -oltage-oltage restraine) o-er current re-erse ,ower un)er?o-er%fre>uenc loss of excitationnegati-e se>uence stator o-er%te/,erature o-er%s,ee) o-er%current an) earth fault for 1*2 (5an) transfor/er ,rotections.

-+2+4+? $V !wit%h#ear and Transmission ine Prote%tion

The basic conce,t of ,rotecti-e rela sche/es on a high -oltage sste/ is to /ini/i9e )a/ageto sste/ e>ui,/ent to /ini/i9e the effects of the sste/ )isturbances an) to ensure that nosingle contingenc will )isable the ,rotection on an ele/ent of the sste/. Thus ,rotecti-erelas /ust be ca,able of reliable o,eration to sense an) isolate all faults ra,i)l. The /ustalso ,ossess a high )egree of securit against unwante) o,erations. For /axi/u/ reliabilit

all circuits of the sste/ shoul) be ,rotecte) b ,rotecti-e sche/es which is ca,able of in)e,en)ent )etection an) isolation of all faults without un)ue )isturbance to the sste/.

'rea(er failure ,rotection shoul) be ,ro-i)e) to tri, all necessar local an) re/ote circuit brea(ers or the unit in the e-ent of a ,articular brea(ers failure to clear the fault.

A basic conce,t of full local bac(%u, ,rotection co/,rising )u,licate high s,ee) line ,rotection using )istance relas o-er current an) earth fault relas ,lus se>uential tri,,ingsche/es for brea(er failure is reco//en)e) for the 1*2 (5 trans/ission lines The associate)rela an) control ,anels will be locate) in the ,owerhouse control roo/.

-+2+4+. >roundin# <)arthin#=

The basic objecti-e of the ,owerhouse transfor/er galler switchar) /ergenc &enerator

buil)ing an) of the re/ote installations groun)ing is

• to ,ro-i)e low resistance groun)ingY





• to li/it the ste, an) touch ,otentials within the acce,table li/its as in)icate) in ;0Y

• to li/it the groun) ,otential rise )uring groun) fault occurrence an) to li/it

o-er-oltagesY• to assure the ,ro,er o,eration of the ,rotecti-e rela sste/.

To be able to obtain the low groun)ing resistance -alue it /ight be necessar to interconnectthe ,owerhouse groun) sste/ to switchar) groun) sste/ an) to tailrace ,on). During)etaile) )esign ,hase groun) resisti-it /easure/ents will ha-e to be )one for the )esign of the groun)ing gri).

S,ecial attention shoul) be ,ai) for the groun)ing of the large /etal objects within 0 /etres of the trans/ission line. The fences surroun)ing the substation will be groun)e) at a,,roxi/ateinter-als of *0 /etres.

-+2+4+4 $V !wit%hyard;!ustation

The ,ro,ose) ,owerhouse is consi)ere) that the su,,l for sste/ as well as for local nee)s.#nl the excess ,ower can be use) for ex,ort fro/ the existing interconnecte) ,ower sste/

,oints to n)ian gri).

For the installation of the 45 switching e>ui,/ent the con-entional out)oor switchar)conce,t is consi)ere). The switchar) will be locate) u,strea/ on the south%east si)e of the

,owerhouse buil)ing. The switchar) has been ,ositione) such a wa to /ini/ise the a/ountof exca-ation necessar for the installation of e>ui,/ent. The generate) ,ower will bee-acuate) at the 1*2 (5 switchar) of "ahughat ,ower station.

The laout of ,owerhouse switchar) is in Dwg no. $"%P4,%01.

-+2+4+6 Control and :ndi%ation at the $eadwor/s

#nl e>ui,/ent failure alar/s at essential gates gate ,osition in)ication water le-els trash%rac( )ifferential in)ications will be trans/itte) to the ,owerhouse Control "oo/.

-+2+4+- Communi%ation !ystem

!A ,resentl has a co//unication sste/ between ,owerhouses the loa) )is,atch centreBLDC an) substations which is acco/,lishe) b three basic /eans na/el ,ower line carrier BPLCC fibber o,tical networ(s an) Trun( Dialing tele,hone sste/.

Two co//unication sste/s centre) in the ,ower station Control "oo/ can be en-isage)

• #,tical fibre circuits for co//unications fro/ the ,owerhouse to "aughat through 7o)isubstation an) to the Loa) Dis,atch Centre BLDC. 'oth sste/s can carr s,eech an) )ata.

• A Trun( Dialing tele,hone ser-ice in the Control "oo/ for co//unication with the LDCan) $,,er "aughat 4P.





Pro-ision for trans/ission of )ata an) sste/ status to the SCADA sste/ at !AHs LDC in=ath/an)u shoul) also be consi)ere).

An internal tele,hone sste/ is foreseen for the ,owerhouse its offices an) wor(sho,s thee/ergenc generator buil)ing the resi)ence of o,erational ,ersonnel guar) houses an) thehea)wor(s control roo/. A tele,hone sste/ with two external lines will also be ,ro-i)e).

-+2+6 Transmission ine

A )etaile) ,ower e-acuation stu) was carrie) out for $,,er "aughat 4)ro,ower Project inconsi)eration of three alternati-e sche/es. All the alternati-e sche/es were co/,are) on theas,ect of technical an) econo/ical analsis results. The )etails regar)ing the analsis of thesethree sche/es are ,resente) in Cha,ter 10 of this re,ort.

A/ong the anal9e) cases base) on technical an) econo/ical analsis -iew of constructiono,eration s,ace constrains an) /aintenance of substation facilit in connection ,oint an)

,ower losses on line an) e>ui,/ent Sche/e%1 i.e. the sche/e with an ; (/ long 1*2 (5 singlecircuit trans/ission line on lattice structures with 'ear con)uctors fro/ $,,er "ahughat4)roelectric Project to "aughat 4P being constructe) b !A is reco//en)e) for the

,ower e-acuation sste/.

The )etails of the stu) regar)ing the choice of the a,,ro,riate alternati-e are )escribe) inCha,ter 10 Power -acuation Stu).

-+2+- Constru%tion Power

Alternati-es for the su,,l of construction ,ower )uring the construction of $,,er "ahughat4P ,roject are as follows

• Pre%buil)ing of 1*2 (5 trans/ission line fro/ "ahughat 4P to the $,,er "ahughat ,roject site. This will re>uire installation of 1*2 (5 line ba at theswitchar) of "ahughat 4P an) a 1*2?11 (5 substation at $,,er "ahughat

• ,owerhouse an) 11?0.+ (5 * ,hase ste,%)own )istribution transfor/ers at theconstruction sites.

• Construction of a ** (5 trans/ission line fro/ the nearest **?11 (5 substation at$,,er "ahughat 4P or the construction of a 11 (5 )istribution line to the ,rojectsite. Fre>uenc of tri,,ing in 11 (5 fee)ers /a be significantl high.

• Pro-ision of a )iesel generator on site. De,en)ing on the loa) it will be necessar toinstall a )iesel generator unit an) a L5 )istribution boar) for ,ower )istribution tothe )ifferent loa) centres aroun) the construction site. Although the unit installation

ti/e is shorter the o-erall cost for o,eration an) /aintenance are high. Due to ,roble/s relate) to fuel su,,l trans,ort han)ling this solution is not consi)ere) to be the best o,tion.





For the construction site essential loa)s a bac(%u, e/ergenc )iesel generator unit isreco//en)e). This e/ergenc )iesel set woul) be ,ro-i)e) b the general contractor.

-+2+10 Power >eneration at a#ar Khola

As /entione) in the ,re-ious sections the ,owerhouse ,ro,ose) to be locate) at 'agar =holawill be consist two nu/bers of 10 =8 generators. The generator -oltage will be +00 5. #nethree ,hase 0.+?11 (5 ste,%u, transfor/er will be ,ro-i)e) for ,ower e-acuation in 11 (5 local)istribution sste/s. A 00 5 7e)iu/ -oltage switchgear will be ,ro-i)e) for control an)

,rotection of generator an) low -oltage si)e of the transfor/er. A 12 (5 -acuu/ circuit brea(er switchgear will be ,ro-i)e) for control an) ,rotection of the line. This switchgear will ,rotectthe 11 (5 line )uring an earth fault o-erloa)ing an) to ,ro-i)e safet.

The /ain ,reli/inar ,ara/eters of the generator an) ,ower transfor/er are su//ari9e) in the

following table

Tale -50 Main Parameters 7or >enerators and Trans7ormers

Para/eter 5alue"ating generator 10 (8Power factor 0.;Fre>uenc 0"ate) -oltage Three ,hase +00 5

"ating Transfor/er +00 (5A

"ate) -oltage at 45 11 (5"ate) -oltage at L5 +00 5Phase Three ,hase star?)elta




Upper Rahughat Hydroelectric Project Po(er )"acuation Study

10+0 PO9)R )V'C"'T:ON !T"8A

10+1 :ntrodu%tion

The ,owerhouse of $,,er "ahughat 4)roelectric Project has been ,ro,ose) on the left ban( of "ahughat =hola in the -icinit of Dagna/ 5illage De-elo,/ent Co//ittee of 7ag)i District.The ca,acit of the ,ower ,lant is ex,ecte) to be +;. 78. The generate) electric ,ower will be

)eli-ere) to ntegrate) !e,al Power Sste/ B!PS through a 1*2 (5 high -oltage trans/issionline. A *20 =8 ,owerhouse has also been ,lanne) at 'agar =hola an) it is ex,ecte) that theenerg generatie) fro/ this ,owerhouse will be e-acuate) to the nearest )istribution line.

The ,roject is sche)ule) to be co//issione) a,,roxi/atel ears fro/ its )ate of i/,le/entation. For the ,ur,ose of this ,ower e-acuation stu) it has been assu/e) that this

,roject will be co//issione) b F6 201;%1<. There are other s/all ,ower ,rojects being ,lanne) in the close -icinit of this ,roject an) the ,robabilit of their being co//issione) atabout the sa/e ti/e is fairl high therefore the generation ex,ansion ,lan reco//en)s the

buil)ing of a co//on trans/ission sste/ to e-acuate ,ower in !PS. The /ain objecti-e of the ,ower e-acuation stu) of this ,roject is thus to i)entif the least%cost se>uence of

trans/ission line sche/es.

The selection of trans/ission lines for the loa)s as well as the ,lanne) ,ower ,lants in !e,al are base) on the econo/ic e-aluation of )ifferent line?tower solutions o-er the lifeti/e of the ,roject. The o,ti/i9ation of the trans/ission line sche/es ta(es into account the in-est/entcost cost of trans/ission losses an) o,eration an) /aintenance costs.

10+2 )(istin# Transmission !ystem

The ,resent trans/ission line -oltages use) in the countr for ,ower e-acuation are 1*2 (5

(5 an) ** (5. Presentl the !PS trans/ission sste/ is )o/inate) b an east%west 1*2 (5 tiefro/ Anar/ani in the east to 7ahen)ranagar in the west. The /ajor ,art of this tie has a singlecircuit stringing on )ouble circuit towers exce,t for 4etau)a E Dhal(ebar E Lahan sectionwhich has a )ouble circuit. The stringing of the secon) circuit in these existing towers wasco/,lete) last ear.

To e-acuate the generation fro/ the countrHs biggest ,ower ,roject =ali &an)a(i [AH )oublecircuit lines were constructe) fro/ =ali &an)a(i 4)roelectric Project to 'utwal an) a singlecircuit line fro/ =ali &an)a(i to Le(hnath near Po(hara.

=ath/an)u 5alle is the countrHs biggest loa) center an) is ,resentl su,,lie) through aco/bination of an) 1*2 (5 lines. Trisuli De-ighat Sun(oshi an) =ule(hani su,,l ,ower at (5 while =ule(hani 7arsang)i 7i))le 7arsang)i =hi/ti an) 'hote(oshi Projects


Chapter Ten

PO9)R )V'C"'T:ON !T"8A




su,,l ,ower at 1*2 (5. Siuchatar 'ha(ta,ur an) 'alaju are the /ajor gri) substations of the-alle. nterconnection between 1*2 an) (5 is ,ro-i)e) through 1*2? (5 transfor/ers

locate) in these substations.

So/e 1*2 (5 lines are connecte) with the 1*2 (5 n)ian sste/s i.e. &an)a( 4PS to "a/nagar Bn)iaY Duhabi to 'hantabari Bn)ia an) 7ahen)ranagar to Tana(,ur Bn)ia.

The ** (5 sub trans/ission sste/s are in use to )eli-er ,ower fro/ 3hi/ru( An)hi(hola an)Puwa =hola 4)ro,ower Stations to the nearest gri).

De/an) is ex,ecte) to grow at a higher rate in the future since the electrification ratio is stilllow an) there is a large ,otential for ,ower )e/an). !A has ta(en the initiati-e to electrif all

the : )istricts in the countr. !A is also co//itte) to /eet the target of &o-ern/ent of !e,alto increase the electrification ratio.

10+ Transmission ine in the Vi%inity

The nearest substation in the !PS for ,ower e-acuation of $,,er "ahughat 4)roelectricProject is "ahughat 4)roelectric Project B*0 78 which is being constructe) b !A. The

,owerhouse of this ,roject is locate) about ; (/ south fro/ $,,er "ahughat 4)roelectricProject. The e-acuation of ,ower fro/ $,,er "aughat 4P will re)uce ,ower )eficit an) lossesin the !A sste/ an) is ex,ecte) to i/,ro-e -oltage ,rofile in that region.

Se-eral h)ro,ower ,rojects ha-e been i)entifie) along the "ahughat "i-er 'asin an) the total ,otential in the -icinit of this region is esti/ate) to be a,,roxi/atel 10 78. 7ost of thei)entifie) ,otential generation ,lants are within 1 (/ fro/ "ahughat 4P B!A. t isen-isage) that the ,ro,ose) trans/ission line of this ,roject will be the bac(bone of e-acuationsste/ for future generation in this region.

10+5 Transmission Volta#e sele%tion

This ,ower e-acuation stu) is inten)e) to i)entif techno%econo/icall -iable trans/issionsste/ to e-acuate the ,ower fro/ the ,rojects in this region to the !PS gri). n or)er to selectthe best o,tion se-eral sche/es were for/ulate) an) anal9e).

10+? Volta#e !ele%tion "sin# )mpiri%al Formula

#ne of the >uic( /etho)s to esti/ate trans/ission lines -oltage is b Stills For/ula

5V. W \ B0.WL X P?100

whereL % Length ](/^P % Power to trans/it ](8^





Fi#ure 102? Chart 7or !tills Formula 7or Transmission

The chart ,re,are) base) on StillHs for/ula for trans/ission -oltage selection is shown abo-e.Accor)ing to the chart the a,,ro,riate trans/ission -oltage for +;. 78 is 1*0 (5. 4ence thenearest stan)ar) of trans/ission -oltage le-el is 1*2 (5.

10+. Volta#e !ele%tion ased "pon Volta#e o7 the o%al !ustation

The selection of the trans/ission -oltage is also influence) b -oltage use) in neighboringsubstations where sste/ interconnection /a be )esire). The sste/ -oltage at the nearest

,oint or neighboring stations where ,ower will be e-acuate) is ** (5 or 1*2 (5. The existing** (5 )istribution line )oes not ha-e enough ca,acit to transfer +;. 78. Secon)l a 1*2 (5trans/ission sste/ will be a-ailable at the un)er construction "aughat 4P which is ; (/south fro/ the ,roject. The ,ro,ose) 1*2 (5 trans/ission line with 'ear con)uctor has enoughther/al ca,acit to e-acuate +;. 78 of ,ower.

10+4 Volta#e !ele%tion "sin# Capitalied Cost

The e-acuation stu) inclu)ing for/ulation of the sche/es was con)ucte) with the co/bine)use of two )ifferent ,lanning /etho)s

7etho) 13

Direct s,rea)sheet calculation for )eter/ining the o,ti/u/ con)uctor si9e an) -oltage le-el. tis base) on ca,itali9e) cost ,er (/ of trans/ission line.

7etho) 23





Sste/ stu)ies using loa) flow software. 4ere o,ti/i9ation is base) on costs an) benefits for the sste/ with substation%wise loa) forecast an) generation ,roject.

10+4+1 Method 1

#,ti/u/ con)uctor si9e an) -oltage le-el is calculate) base) on ca,itali9e) cost ,er (/trans/ission line length using a s,rea)%sheet. This /etho) is a,,licable to trans/ission linesthat are not subjecte) to loa) growth.

The selection of trans/ission lines for the ,lanne) ,ower ,lants in !e,al are base) on econo/ic

e-aluation ta(ing into account trans/ission sste/ ,lanning focusing on the establish/ent of necessar extension to the integrate) sste/ in or)er to connect new generation ,lants an)transfer the ,ower fro/ the ,lants to the loa) center in an econo/ic an) reliable /anner.

The -oltage is selecte) for the stan)ar) trans/ission line -oltage use) in ,ower sste/ for /e)iu/ ,ower ,rojects i.e. (5 or 1*2 (5 )e,en)ing u,on >uantu/ of ,ower to betrans/itte).

#,ti/i9ation stu) of trans/ission -oltage le-el is carrie) out base) on ca,itali9e) cost ,er (/line using s,rea)%sheet for )ifferent -oltage an) con)uctor si9e. The o,ti/i9ation ta(es intoaccount in-est/ent cost cost of trans/ission losses an) o,eration an) /aintenance cost. Thefollowing for/ulae a,,l to the calculation.

= total V = in-est/ent X= loss X = #I7 ]1000 $SD?(/^

= loss V BP ,ea( ? $ rate)2 W " W T loss W ( e W D

= #I7 V C in-est/ent W C #I7 ? 100 W D ]1000 $SD?(/^

8here

P ,ea( % 7axi/u/ trans/itte) Power ]78^

$ rate) % "ate) trans/ission 5oltage ](5^

" % AC "esistance of con)uctor ]#h/?(/^

T loss % Loss Duration ]4our^

( e % nerg Cost ]$Sc?(8h^

D % Discount Factor

C #I7 % Annual #,eration I 7aintenance Cost BO of initial in-est/ent

10+4+1+1 Plant Costs

Trans/ission line costs are state) in the Annex 4. The s,rea)sheet o,ti/i9ation is carrie) out base) on the trans/ission line costs alone but the substation costs are a))e) before a finalreco//en)ation is gi-en.





10+4+1+2 Plant oss 8uration

The e>ui-alent loss )uration is calculate) fro/ the ,lant factors. The e>ui-alent loss )uration

shoul) be un)erstoo) as the ti/e the ,lant will ha-e to be o,erate) on rate) ca,acit in or)er to ,ro)uce the annual losses an) is calculate) below

Tale 1051 Plant oss 8uration

Location Plant Total annual Full Energ Plant Plant lo!!

"i!trict #a$acit Energ Factor %uration

&W 'W( 'W( (r!.

)$$er *aug(at +EP 48.5 284.41 42,.24 0.664 4463

10+4+1+ )ner#y Cost

The energ cost nor/all to be use) for o,ti/i9ation of trans/ission lines is the long run/arginal cost of generation. n !e,al it has been agree) that an a-erage incre/ental cost of generation better reflects the real -alue an) is therefore use) for the o,ti/i9ation stu). Thea-erage incre/ental cost of generation is

A-erage ncre/ental Cost total .02 $Sc?(8h

#nl the total AC will be use) in the o,ti/i9ation of trans/ission lines.

10+4+1+5 Operation and Maintenan%e

The o,eration an) /aintenance cost of trans/ission line is set to 1.O of the initial in-est/entuse) in !A. T,ical figures range fro/ 0.O to 1.O an) !e,al /a well be in the u,,er range of this )ue to the recurring /onsoon an) fre>uent lan)sli)es. An annual o,eration an)/aintenance cost of 1.O has therefore been use) in the o,ti/i9ation.

10+4+1+? 8is%ount Fa%tor

The )iscount factor re,resents the )iscounte) -alue of fixe) annual ,a/ents of one unit eachear of the lifeti/e. 8ith *0 ears technical lifeti/e an) 10 O )iscount rate the )iscount factor is <.+*.

The result of ,ure s,rea)sheet o,ti/i9ation for the ,roject is )escribe) below. The result of thes,rea)sheet econo/ic o,ti/i9ation of trans/ission lines fro/ the ,rojects are also shownsche/aticall in figure.





Fi#ure 102. Capitalied Cost *ersus :nstalled Capa%ity Cur*e

Figure 10%2 abo-e shows the ca,itali9e) cost -s. the installe) ca,acit cur-e. This figure showsthat the o,ti/u/ sste/ is a single circuit 1*2 (5 line with 'ear BACS" 1x20 s>.//con)uctor for the ,ower e-acuation of +;. 78 for a loss )uration of ++* hrs. This -oltage

will be a-ailable in the -icinit of the ,roject soon. A 1*2 (5 line with ACS" B1x20 s>.//con)uctor follows !AHs stan)ar) con)uctor si9e co)e 'A". Consi)ering this gui)elinese-eral alternati-e sche/es for connecting $,,er "ahughat 4P to the !PS sste/ ha-e beenfor/ulate).

10+4+2 Method 2

The o,ti/i9ation is carrie) out b calculating total ca,itali9e) costs for the entire hori9on fro/F6 201+%1 u, to F6 20*2%**. The cost ele/ents consi)ere) are in-est/ent o,eration an)/aintenance an) sste/ losses. The technical an) econo/ical analses of )ifferent sche/esstu)ie) are as follows





10+4+ 'lternati*e !%heme

Altogether three alternati-e sche/es were )e-elo,e) for the loa) flow acti-ities in the

e-acuation stu). The are as follows

!%heme13

Construction of a ; (/ long 1*2 (5 S?C trans/ission line with 'ear B20 s>. // ACS"con)uctors fro/ $,,er "ahughat 4P to "ahughat 4P B!A an) one 1*2 (5 line baextension at "ahughat 4P B!A. The cost of the sche/e with ,roject co/,onents is esti/ate)to be ($SN +:.+

!%heme23

Construction of a ; (/ long 1*2 (5 S?C trans/ission line with Duc( B*00 s>. // ACS"con)uctors fro/ $,,er "ahughat 4P to "ahughat 4P B!A an) one 1*2 (5 line baextension at "ahughat 4P B!A. The cost of the sche/e with ,roject co/,onents is esti/ate)to be ($SN +:.+

!%heme3

Construction of a ; (/ long 1*2 (5 D?C trans/ission line with 'ear B20 s>. // ACS"con)uctors fro/ $,,er "ahughat 4P to "ahughat 4P B!A an) one 1*2 (5 line baextension at "ahughat 4P B!A. The cost of the sche/e with ,roject co/,onents is esti/ate)to be ($SN 1;+.+

10+4++1 Te%hni%al 'nalysis

n,ut )ata for loa) flow stu) are calculate) on 100 75A base an) line ,ara/eters " M an) 'are calculate) ,er 100 (/ consi)ering sste/ ,ower factor of 0.<.

Loa) flow stu) was carrie) out for the three alternati-e sche/es for/e) for the ,ower e-acuation of $,,er "ahughat 4)roelectric Project. The si/ulations were carrie) out with thehel, of a co/,uter ,rogra/. The stu) is base) on the substation wise loa) forecast an) generation ,lan as in)icate) in

!As ,re-ious re,orts. The stu) is carrie) out onl for the sste/ ,ea( ,erio) as this is the/ost se-ere situation.

The stu)ies for all the sche/es were )one for the ,erio) fro/ F6 201+%1 Bco//issioning earto F6 20*2%**.

8hile si/ulating the loa) flow the out,ut results were chec(e) for o-erloa)ing of trans/issionlines or transfor/ers -oltage li/its at all buses reacti-e ,ower li/its in generator etc.

t is obser-e) that loa)ing on /ost of the 1*2 (5 lines are in or)er un)er nor/al con)ition. Theloa) flow results are gi-en in Annex . The sste/ losses obtaine) fro/ the loa) flow stu)ieswith -arious sche/es are use) for econo/ical analsis.

The loss figures are utili9e) in the cono/ic Analsis which is ex,laine) below





10+4++2 )%onomi% 'nalysis

The e-acuation of ,ower fro/ the )ifferent alternati-es has been )iscusse) earlier. An analsis

in econo/ic ter/s has to be carrie) out to choose the best alternati-e a/ong the )ifferentalternati-es loo(e) into. This i/,lies that for foreign cost co/,onent bor)er ,rices ,lus localcosts to the site ha-e to be use). The local cost co/,onent is con-erte) into econo/ic cost ba,,ling the stan)ar) con-ersion factor of 0.< to the /ar(et ,rices. The factor of 0.< isco//onl use) for ,ower sector ,rojects in the countr an) is a generali9e) factor ex,ressingthe o,,ortunit cost of local resources. Local taxes )uties an) subsi)ies that )istort trueecono/ic costs are re/o-e) fro/ the /ar(et ,rices.

The econo/ic analsis is carrie) out b the usual )iscounte) cash flow techni>ue. The toola,,lie) is the Present 5alue 7etho). An alternati-e with the least cost in the ,resent -alue is

ob-iousl the best alternati-e.

The rele-ant s,ecific econo/ic ,ara/eters that will be a,,lie) for the econo/ic analsis ha-e been ex,laine) earlier.

All ,rices an) calculations are ex,resse) in constant ter/s.

10+4++ )%onomi% :n*estment Cost

The cost esti/ate for all the alternati-es are base) on calculate) unit rates. These unit rates )onot inclu)e taxes an) )uties. Local cost co/,onent is assu/e) to be 20 ,ercent of the total cost.

To reflect o,,ortunit cost of local resources a)just/ents to local cost b a,,ling the stan)ar)con-ersion factor of 0.< has been )one.

The construction of trans/ission line an) substation is assu/e) to be co/,lete) in two ears.The ,ercentage ,roject cost )isburse/ent is assu/e) to be :0O an) *0 O in the first an) secon)res,ecti-el.

The construction of a substation is assu/e) to be co/,lete) in two ears. The ,ercentage ,roject cost )isburse/ent is assu/e) to be *0 O an) :0 O in the first an) secon) ear res,ecti-el

10+4++5 Result o7 'nalysis

The ,resent ca,itali9e) cost calculate) for each of the trans/ission line alternati-e sche/essu//ari9e) cost is gi-en in Annex . The )etail econo/ic analses wor(e) out aresubse>uentl gi-en in Annex .

10+6 Con%lusions and Re%ommendations

'ase) on the abo-e technical an) financial stu)ies the following conclusions are )rawn

• Technicall a 1*2 (5 line is a)e>uate for the ,ower e-acuation of :0 78 in one circuit

an) no o-erloa)ing is obser-e).

• cono/icall all the alternati-e Sche/es un)er all con)itions that are anal9e) an)ran(e) on the ratio of o,ti/u/ cost.





• The ,resent ca,itali9e) cost of Sche/e%1 is the least cost co/,are) to Sche/e%2 an)Sche/e%*. The ca,itali9e) cost of Sche/e%2 an) Sche/e%* are 1 O an) 2; O /oreres,ecti-el than the cost of Sche/e%1.

• There is a ,ossibilit of other h)ro ,ower ,rojects being)e-elo,e) or ,lanne) b PPs in the -icinit of $,,er "ahughat 4P. The ,ro,ose)single circuit 1*2 (5 line with 'A" con)uctor has a trans/ission ca,acit of :0 78which is ca,able of catering to the a))itional ,ower of other h)ro,ower ,rojects in thefuture.

• The ,ro,ose) *20 (8 ,owerhouse at 'agar (hola will be e-acuate) at the nearest 11?0.+(5 )istribution line.

Fro/ the abo-e technical an) financial analsis as well as fro/ a ,oint of -iew of o,eration an)/aintenance of the line an) the substation an) a consi)eration of /ini/u/ losses in the line an)e>ui,/ent of $,,er "ahughat 4P it is reco//en)e) that alternati-e Sche/e%1 i.e.construction of an ; (/ long 1*2 (5 single circuit line fro/ $,,er "ahughat 4P to "ahughat4P B!A with 'ear con)uctors be selecte).

As /entione) in the ,re-ious cha,ters the construction of "ahughat 4P B!A has alrea) been initiate) an) it is un)erstoo) that this ,roject en-isages the construction of a trans/issionline fro/ its ,owerhouse u, to the ,owerhouse of 7o)i 4P an) it can also be en-isage) thatthis stretch of the trans/ission line will be in ,lace in the near future. The stu) for "ahughat

7angale 4P en-isages that its ,ower e-acuation will be carrie) out fro/ its ,owerhouse u, tothe ,owerhouse of "ahughat 4P being built b !A -ia a single circuit line an) fro/ here u,to the ,owerhouse of 7o)i 4P -ia another single circuit line. t is also en-isage) that thesecon) circuit fro/ the ,owerhouse of "ahughat 4P u, to the ,owerhouse of 7o)i 4P willha-e the ca,acit to e-acuate the ,ower ,ro)uce) b both "ahughat 7angale 4P as well as$,,er "ahughat 4P. t is also un)erstoo) that the cost of this secon) circuit will be consi)ere)in the cost for the trans/ission line of "ahughat 7angale 4P. The ,ower generate) b thisB$,,er "ahughat 4P ,roject can therefore be e-acuate) in the switchar) of "ahughat 4PBbeing built b !A. Therefore $,,er "ahughat 4P will re>uire the construction of onl asingle circuit line u, to the switchar) of "ahughat 4P B!A.

The e-acuation of ,ower fro/ this ,roject will thus be carrie) out b constructing an ; (/ long1*2 (5 single circuit trans/ission line with ACS" 'ear con)uctors on steel lattice towers

between $,,er "ahughat an) "ahughat 4P B!A. The ,owerhouse substation at $,,er "ahughat 4P will ha-e two nu/bers of 11?1*2 (5 ste, u, three ,hase out)oor ,ower transfor/ers two nu/bers of 1*2 (5 transfor/er bas an) one nu/ber of 1*2 (5 line ba.Li(ewise one nu/ber of 1*2 (5 trans/ission line ba shall be exten)e) at the switchar) of "ahughat 4P B!A.




Upper Rahughat Hydroelectric ProjectProject &utputs and Related *ene+ts

11+0 COMP"T'T:ON OF PRO@)CT O"TP"T! 'N8 R)'T)8

)N)F:T!

11+1 :ntrodu%tion

The )ischarge hea) an) the efficienc are the ,ri/e factors res,onsible for the ,ower generationfro/ a ,lant. Discharge through the turbine )e,en)s on the a-ailabilit of water in the ri-er.4ence it -aries consi)erabl at )ifferent ti/es of a ear. A-ailable hea) )e,en)s on the le-el of water in the ri-er which )e,en)s on the ri-er flow. 'ecause of this fact the a-ailable gross hea)for the generation -aries in accor)ance with the a-ailable flow in the ri-er. 'ut in the case of $,,er "ahughat 4P the go-erning water le-el is at the collection cha/ber at 'agar =holawhich to a great extent re/ains constant throughout the ear. Si/ilarl the go-erning hea))e,en)s on the tail water le-el of "ahughat at ,owerhouse site. As ,elton turbine is use) in the

,ower house the turbine axis will go-ern the gross hea) of the ,roject. 4ence the gross hea) of $,,er "ahughat 4P will re/ain constant throughout the ear. The last ,ara/eter is theefficienc which is )irectl relate) to the e>ui,/ent >ualit an) the generation ca,acit.

fficienc of an e>ui,/ent changes if the flow an) hea) is change) to other than the )esigne) ,ara/eters. For this le-el of stu) the o-erall efficienc of the ,lant is assu/e) to be constant.&eneration ,ara/eters of the ,lant are esti/ate) on the basis of the following

• Power flow of "ahughat 7angale

• A-erage /onthl flow at the 'agar =hola hea)wor(s site.

• !or/al o,erating le-el at the collection cha/ber which is constant. Si/ilarl theturbine axis is fixe). 4ence the gross hea) is assu/e) to re/ain constant throughout the

ear.

• The o-erall efficienc of the ,ower ,lant re/ains constant throughout the ear.

11+2 8ependale Flow

Discharge is a ,ri/e co/,onent for the ,ower generation. Discharge rate is res,onsible for the ,ower whereas the )ischarge -olu/e is relate) to the energ. As the ,roject un)er consi)erationis a run of ri-er t,e there is no ,ro-ision of storage. 4ence energ generation is )irectl

,ro,ortional to the )ischarge rate. The energ generation ,attern follows the )ischarge ,attern of the ri-er. A-erage /onthl flow is use) to esti/ate the /onthl energ of the ,roject. Design

flow of the ,lant is base) on the o,ti/i9ation of )esign flow. #,ti/u/ )esign flow is 1.20 / *?swhich corres,on) to )esign flow of "ahughat 7angale an) the +0O )e,en)able flow of 'agar =hola.


Chapter )le*en

COMP"T'T:ON OF PRO@)CT O"TP"T! 'N8

R)'T)8 )N)F:T!




11+ >ross $ead and Net $ead

The gross hea) is base) on the nor/al water le-el at the collection cha/ber an) the turbine axisle-el. !or/al o,erating le-el at the collection cha/ber is 1+.0 /asl whereas the turbine axisle-el is 11:.0 /asl. 4ence the gross hea) of the ,roject is esti/ate) to be *:;.00 /eters. Thea-erage hea) loss which corres,on)s to the )esign )ischarge is esti/ate) to be .+: /eters. #utof this the total frictional loss is +.* /eters an) a loss of 1.11 /eters constitutes of other losses.The a-erage hea) loss -aries fro/ 0.+2 /eters )uring the )r season to .+: /eters )uring thewet season. This woul) gi-e a /ini/u/ net hea) of *:*.2* /eters )uring the wet season an) a/axi/u/ of *:;.2; /eters )uring the )r season.

The )etails of the hea) loss calculation are ,resente) in Annex F of this re,ort. A su//ar of

the esti/ate) hea) losses fro/ the foreba to the turbine corres,on)ing to the )esign )ischargeis ,resente) in the Table !o. 11%1.

Tale 1152 !ummary o7 the $ead oss <in meters=

8es%ription $ead oss <m=

A. 4ea) "ace Tunnel1 Trashrac( Loss 0.002 ntrance Loss 0.02<* Friction Loss 2.:*++ 'en) Loss 0.011

!u Total 2+44-

+ Dro, Shaft an) Penstoc( 1 Friction Loss 1.2*2 'en) Loss 0.<* 5al-e Loss 0.11+

!u Total 2+.-

Total $ead oss ?+542

11+5 O*erall )77i%ien%y

The o-erall efficienc of a ,ower ,lant )e,en)s on the_ efficienc of the transfor/er generator an) the turbine. A/ong these three efficienc of the turbine -aries with the hea) an) )ischargewhen these -alues ha-e -alues other than the )esigne) ,ara/eter. For this stage of stu) the-ariation of the turbine efficienc is not consi)ere). 4ence the o-erall efficienc of the ,ower

,lant is assu/e) to re/ain constant throughout the ear an) is e>ual to ;.+*O. This -aluecorres,on)s to the following efficiencies

• Transfor/er efficienc % <<.0O• &enerator efficienc % <:.0O• Turbine efficienc % <0.0O.





11+? )ner#y Computation

A s,rea)sheet /o)el was use) in or)er to ,ro-i)e the necessar in,ut into the energco/,utation analsis. Assu/,tions /a)e )uring the esti/ation are as follows

• The water le-el at the collection cha/ber re/ains constant at L 1+.0 /asl throughout the ear

• Turbine axis is fixe) at L 11:.0 /asl. As ,elton turbine is ,ro,ose) the tail water willha-e no effect on generation.

• The gross hea) is *:;.00 /eter throughout the ear.• A-erage hea) loss corres,on)ing to the )esign )ischarge of the ,roject is .+: /eters.• The total hea) loss for the ,ower )ischarge other than the )esign )ischarge is esti/ate)

,ro,ortionatel.• 7ini/u/ )ownstrea/ release of 0.+: /*?s corres,on)ing to the 10 O of the /ini/u/

/onthl flow is consi)ere) as co/,ensation flow.• Sche)ule) an) unsche)ule) outages are not consi)ere) while esti/ating the energ. This

will be consi)ere) in the financial analsis.

'ase) on the abo-e assu/,tions the installe) ca,acit of $,,er "ahughat 4P is esti/ate) to be +;. 78. Total annual energ of 2;+.+1 &8h has been esti/ate) to be generate). This -alueis base) on the a-erage /onthl flow. Assu/ing Poush to Chaitra BTotal Four 7onths as )rseason the total )r season energ is esti/ate) to be +1.;0 &8h where as the total wet seasonenerg is 2+2.1 &8h. 7ini/u/ ,ower generate) fro/ the ,lant is esti/ate) to 1*.+ 78.

The su//ar of the /onthl generation fro/ the ,roject is ,resente) in the Table !o. 11%2.A-erage /onthl ,ower generation shown in this table is esti/ate) on the basis of the a-erage/onthl flows .The )etails of the energ calculation is ,resente) in Annex F.

Tale 115 Monthly )ner#y >eneration 7rom "pper Rahu#hat $)P


'*era#e '*era#e

Month Power )ner#y

<M9= <>9h=

Shrawan +;.01 *.2

'ha)ra +;.01 *.::Ashwin +;.01 *.0;=arti( *.1 2.2:7ansir 21.00 1+.;+Poush 1.1* 11.+;7agh 1+.02 <.:<Falgun 1*.+ <.Chaitra 1+.<; 10.;;'aisa(h 2<.2* 21.:3estha +;.01 *.1<Asar +;.01 *.1<

Total 265+51




11+. )ner#y >eneration 7rom a#ar Khola

'ecause of the to,ogra,h an) the location of the hea)wor( at 'agar =hola it has beenen-isage) that a s/all ,ower generation facilit has also been ,ro,ose) in the hea)wor(s area.'ase) on the o,ti/i9ation stu) the )esign )ischarge fro/ 'agar =hola inta(e is esti/ate) to

be *.20 cu/ecs. The gross hea) is base) on the nor/al water le-els at the )esan)ing basin an)the collection cha/ber. Assu/,tions /a)e )uring the esti/ation of energ fro/ 'agar =hola

,owerhouse are as follows

• The nor/al water le-el at the )esan)ing basin is L 1:.0 /asl where as that incollection cha/ber re/ains constant at L 1+.0 /asl through out the ear

• The gross hea) is 1*.0 /eter throughout the ear.

• A-erage hea) loss corres,on)ing to the )esign )ischarge of the ,roject is 0.10 /eter.• The total hea) loss for the ,ower )ischarge other than the )esign )ischarge is esti/ate)

,ro,ortionatel.• 7ini/u/ )ownstrea/ release of 0.12 /*?s corres,on)ing to the 10 O of the /ini/u/

/onthl flow is consi)ere) as co/,ensation flow.• Sche)ule) an) unsche)ule) outages are not consi)ere) while esti/ating the energ. This

will be consi)ere) in the financial analsis.

'ase) on the abo-e assu/,tions the installe) ca,acit of the ,owerhouse at 'agar =hola isesti/ate) to be 0.*2 78. Total annual energ of 2.0+ &8h has been esti/ate) to be generate).

This -alue is base) on the a-erage /onthl flow. Assu/ing Poush to Chaitra BTotal Four 7onths as )r season the total )r season energ is esti/ate) to be 0.** &8h where as thetotal wet season energ is 1.:1 &8h. 7ini/u/ ,ower generate) fro/ the ,lant is esti/ate) to0.10 78.

The su//ar of the /onthl generation fro/ the ,roject is ,resente) in the Table !o. 11%*.

Tale 1155 Monthly )ner#y >eneration 7rom a#ar Khola


'*era#e '*era#e

Month Power )ner#y

<M9= <>9h=Shrawan 0.*2 0.2+'ha)ra 0.*2 0.2+Ashwin 0.*2 0.2+=arti( 0.*0 0.217ansir 0.1; 0.1*Poush 0.1* 0.0<7agh 0.11 0.0;Falgun 0.10 0.0:Chaitra 0.1* 0.0<

'aisa(h 0.2+ 0.1:3estha 0.*2 0.2+Asar 0.*2 0.2+Total 2+05



Upper Rahughat Hydroelectric ProjectConstruction Planning

12+0 CON!TR"CT:ON P'NN:N>

12+1 >eneral

Construction ,lanning is one of the /ajor co/,onents of the ,roject stu) that trans,ires intothe successful )e-elo,/ent of the ,roject within the sti,ulate) ti/e an) the esti/ate) bu)get.

$,,er "ahughat 4)roelectric Project is locate) in Pa(ha,ani 5DC Chi/(ola 5DC an)Dagna/ Dar/ija 5DC of 7ag)i District in 8estern !e,al. The site is locate) about **+ (/northwest of =ath/an)u an) about ;* =/ west of Po(hara.

"ahughat "i-er is a /ajor tributar of =ali &an)a(i "i-er an) /eets the =ali &an)a(i "i-er near the ,lace calle) &aleshwor of &hatan 5DC. The ,roject site lies between latitu)es of 2;02J+K an) 2;02;J*0 !orth an) between longitu)es ;*0*0J00K an) ;*0*1J0K ast. The

,ro,ose) hea)wor(s site is locate) about 10 / u,strea/ fro/ the confluence of 'agar =holaan) "ahughat "i-er near Chi/(hola 5illage. The ,owerhouse is ,ro,ose) to be locate) on theleft ban( of "ahughat "i-er a,,roxi/atel :00 / u,strea/ fro/ the hea)wor(s of the "ahughat

4)ro,ower Project being constructe) b !e,al lectricit Authorit.The laout of the ,roject is shown in Dwg. !o. $"%PL%01.

12+2 !ite Condition

12+2+1 Topo#raphy and and "se

The ,roject site is locate) in the /i) hill region at ele-ations ranging fro/ 100 to 1100 /asl.Although $,,er "ahughat 4P is a casca)e )e-elo,/ent of "ahughat 7angale 4P it isen-isage) that the )ischarge fro/ 'agar will also be use) for the generation of ,ower in)i-i)uall as well as b /eans of a))ing it to the )esign flow fro/ "ahughat 7angale 4P.

The inta(e site for the ,roject at 'agar =hola is locate) at a relati-el le-el terrain on the left ban( of the =hola while the ,owerhouse site is locate) on a stee, stretch of the ri-er along theleft ban( of "ahughat =hola.

12+2+2 Climati% Conditions

The ,roject area has hot su//er season with /axi/u/ te/,eratures ranging fro/ * oC to+1oC. The /ini/u/ te/,erature )uring winter ranges fro/ 1. oC to :oC. The a-erage annualrainfall is a,,roxi/atel *000 // which occurs )uring the /onth of 3ul%Se,te/ber.

12+ '%%ess to the !ite


Chapter Twel*e

CON!TR"CT:ON P'NN:N>




$,,er "ahughat 4)roelectric Project is a casca)e )e-elo,/ent of "ahughat 7angale 4P ,roject an) )oes not ha-e a /otorable access roa) at ,resent. The nearest roa)hea) to this ,roject is an earthen roa) originating fro/ &aleshor u, to =ha,sin)a)a. This roa) is about (/

long. &aleshwor lies about * (/ north of 'eni on the 'eni % 3o/so/ roa). 'eni the )istricthea) >uarter of 7ag)i District is accessible b a 1* (/ long gra-el roa) that originates fro/7al Dhunga on Po(hara 'aglung 4ighwa.

As /entione) earlier !A is currentl constructing "ahughat 4)roelectric Project thehea)wor(s structure of which is locate) about :00 / )ownstrea/ of the ,owerhouse site

,ro,ose) for this ,roject. t is en-isage) that the access roa) u, to the hea)wor(s site of the"ahughat 4)roelectric Project being i/,le/ente) b !A will alrea) be in ,lace before thei/,le/entation of this ,roject. A -illage roa) which is fairl wi)e exists at ,resent fro/ a ,lacecalle) 7awa,hant u, to Chi/ =hola -illage. The length of this roa) is a,,roxi/atel 20 (/.Chi/ =hola -illage is locate) a)jacent to 'agar =hola which is site for the hea)wor(s of $"4P an) the ,owerhouse site of "74P. t is therefore en-isage) that a,,roxi/atel 20 (/of access roa) will nee) to be constructe) b the ,roject.

A,art fro/ this access roa) ,roject roa)s will be re>uire) to gain access to the following ,rojectareas.

• The ,owerhouse area

• The switchar) area

• The )ro, shaft ,ortal area

• The hea)race tunnel outlet ,ortal area

• The to, of the surgetan( area

• The hea)wor(s area at 'agar =hola

t is en-isage) that about ; (/ of internal ,roject will nee) to be constructe) to ha-e access tothese sites as well as ,ro-i)e access to the three a)it tunnel ,ortals. t is therefore en-isage) thata total length of 2; (/ of roa)s will be nee)e) for the ,roject.

12+5 Constru%tion o7 "pper Rahu#hat $ydroele%tri% Pro&e%t

As /entione) in the ,re-ious cha,ters "ahughat 7angale 4P is locate) i//e)iatel u,strea/of this ,roject an) $,,er "ahughat 4)roelectric Project is being )e-elo,e) as a casca)e)e-elo,/ent to this ,roject. t is en-isage) that the i/,le/entation of these two ,rojects will be

carrie) out in such a wa that both of the/ will start their co//ercial o,eration at the sa/eti/e. As a result the se>uencing of the costruction of the two ,rojects is lin(e) to each other.This is true es,eciall in the construction of the access roa) an) the trans/ission lines. The





)e-elo,ers of the two ,rojects will nee) to wor( in close coor)ination for the i/,le/entation of the two ,rojects.

The 20 (/ of access roa) fro/ the hea)wor(s structure of "ahughat 4P B!A u, to thehea)wor(s structure of this ,roject which is also the ,owerhouse site of "ahughat 7angale 4Pwill be a ,art of this ,roject. n other wor)s the cost for the construction this stretch of theaccess roa) will be inclu)e) in the cost for $,,er "ahughat 4P an) conse>uentl will beconstructe) b the )e-elo,er of this ,roject. t is en-isage) that a ,erio) of a,,roxi/atel twoears will be re>uire) for this acti-it. Since both of these ,rojects are being ,lanne) so that theconstruction of both of the/ finish at a,,roxi/atel the sa/e ti/e the construction of this

,roject will ha-e to be )elae) b a,,roxi/atel one ear. During this one ear it is ex,ecte)

that the construction of the access roa) re>uire) for the access to the hea)wor(s of "ahughat

7angale 4P will be finishe). 8ith this arrange/ent it is en-isage) that both "ahugaht7angale an) $,,er "ahughat 4Ps will be co/,lete) at about the sa/e ti/e.

The total construction ,erio) for this ,roject will therefore be a,,roxi/atel ears. Theconstruction of the access roa) will therefore be the /ajor acti-it )uring the first two ears of the construction of this ,roject. t will also inclu)e acti-ities such as the ac>uisition of lan) an)the )etaile) engineering )esign of the ,roject. #nce the access roa) has reache) the confluenceof 'agar =hola an) "ahughat =hola the construction of the access roa) for the access to thehea)wor(s site of "ahughat 7angale 4P will be initiate) b the )e-elo,er of this ,roject. The

,erio) re>uire) for the costruction of this roa) is esti/ate) to be at least one ear.

This one ear ,erio) will be use) for finishing of the )etaile) engineering )esign ten)ering an)awar) of constracts inclu)ing h)ro/echanical electro/echanical an) the trans/ission line. twill also inclu)e the construction of ca/, facilities an) the /obili9ation of the ci-il wor(s.

The construction ,erio) of this ,roject can thus be categori9e) into two )istinct stages. The firststage will be the construction of the access roa) an) other ,re,arator wor(s while the secon)stage will consist of the actual construction of the ,roject. These will tentati-el )i-i)e) into

,erio)s of three ears. The total )uration for the construction of this ,roject inclu)ingengineering construction of access roa) an) other ,re,arator wor(s is therefore about :2/onths.

The first stage of the ,roject consisting of acti-ities such as the )etaile) )esign inclu)ing the ,re,aration of ten)er )ocu/ents ten)ering lan) ac>uisition construction of infrastructureinclu)ing the access roa) an) other initial wor(s will last for a,,roxi/atel three ears while theactual construction of the ,roject after /obili9ation will also re>uire a ,erio) of a,,roxi/atelthree ears.

12+5+1 Constru%tion Camp

A construction ca/, will be re>uire) to house both the e/,loers staff an) contractors staff.The ca/,site will be locate) near the ,ro,ose) surge tan( site of $,,er "ahughat =hola 4P

towar)s the -illage of Dagna/ B3ethi. The ca/, will co/,rise of office li-ing >uarters storewor(sho, etc. t is en-isage) that ,er/anent structures of the ca/, will be use) for acco//o)ation of the o,eration an) /aintenance staff once the construction is co/,lete).About /onths ti/e will be re>uire) to co/,lete the construction of ca/,s.





12+5+2 Pro&e%t Constru%tion 9or/ and Constru%tion Plannin#

All construction acti-ities for $,,er "ahughat =hola 4P will /ainl be concentrate) at six

locations na/el the 'agar =hola hea)wor(s site the to, of the surgetan( the hea)race tunneloutlet ,ortal the )ro,shaft outlet ,ortal an) the ,owerhouse area. The following are the /ainacti-ities antici,ate) for the construction of the ,roject.

• Construction of the access roa) u, to the ,roject sites• Construction of the ca/, facilities• Construction of the weir un)ersluice inta(e )esan)er foreba ,owerhouse collection

su/, an) cut an) co-er box cul-ert at 'agar =hola hea)wor(s site

• Construction of A)it !o. 1 2 an) *.

• Construction of the hea)race tunnel• Construction of the surgetan( • Construction of the surface ,enstoc( an) anchor bloc(s• Construction of the incline) )ro, shaft an) high ,ressure tunnel• Construction of the ,owerhouse inclu)ing the electro/echanical facilities• Construction of the tailrace an) the switchar)• Construction of the trans/ission line

The laout of the ,roject is shown in Dwg. !o. $"%PL%01 an) the construction sche)ule isshown in Figure 12.1. The wor( in-ol-e) for each of the acti-ities is outline) below.

The access roa) will be constructe) to ,ro-i)e access to the )ifferent ,roject sites as well asother necessar wor( areas ca/, sites borrow areas an) )is,osal areas. The basic assu/,tionsfor the construction of the ,rinci,al ,roject co/,onents an) their se>uence of acti-ities an)construction wor(s to be execute) in the ,roject area are ,resente) in the following sections.

12+5+ asi% 'ssumptions

The following are the basic assu/,tions use) for the construction ,lanning

• 8or( will be )one se-en )as a wee(.

• ight hours ,er shift is assu/e).

• Detaile) engineering wor( is assu/e) to re>uire a,,roxi/atel one ear.

• Financial arrange/ent inclu)ing the ten)ering of the /ain contract an) the

construction of the access roa) will be finali9e) ,rior to the co//ence/ent of theactual construction wor(s.

• Lan) ac>uisition construction of ca/,s an) other ,re,arator wor(s will be

co/,lete) ,rior to the beginning of the construction wor(s of the actual ,rojectco/,onents.

• The exca-ation of the hea)race tunnel will be starte) fro/ six faces.





n or)er to ta(e into consi)eration the econo/ic as,ects with res,ect to the cost re>uire) for thefinancing of the ,roject the construction of the )ifferent ,roject co/,onents within thehea)wor(s co/,lex has been se>uence) such these structures are co/,lete) about the sa/e

ti/e as the co/,letion )ate of other structures es,eciall the hea)race tunnel. n this wa thecost of ca,ital re>uire) for these structures can be /ini/i9e).

12+5+5 8i*ersion 8urin# Constru%tion

8ith new tren)s in the i/,le/entation of h)ro ,rojects in !e,al it is ex,ecte) that theconstruction of the ,roject will in-ol-e local /eans an) /an,ower to a great extent. "i-er )i-ersion wor(s will be carrie) out b channeli9ing one ban( of the ri-er while constructionwor(s on the other ban( will be carrie) out. Due to the -er stee, nature of the ri-er the)i-ersion floo) can be containe) b constructing a -er low coffer)a/. The 110 ear annual

)r season floo) has been consi)ere) for the )i-ersion wor(s.

The )i-ersion ,roce)ures for the construction of the weir the un)ersluices an) the gra-elejector all of which are locate) along the left ban( of 'agar =hola will be un)erta(en b theconstruction of a longitu)inal coffer)a/ an) )i-erting the flow along the right ban( of the /ainri-er channel while the construction of the structures on the left ban( of the channel ta(es ,lace.The construction of the hea)wor(s can start as soon as the /onsoon flows start to rece)e at theen) of the fifth ear an) the longitu)inal coffer)a/ is in ,lace. The construction of the ,rojectwill therefore co//ence towar)s the en) of the fifth ear an) continue right through to the sixthear. Following the co/,letion of the construction of the un)ersluice an) the /ain gui)ewallthe initiall constructe) coffer)a/ will be realigne) so that it is in align/ent with the gui)e wall

se,arating the un)ersluice an) the /ain weir. The u,strea/ an) )ownstrea/ ,arts of this secon)stage coffer)a/ will butt against the u,strea/ an) )ownstrea/ en)s of the gui)e wall an) willcut off the flow fro/ the /ain ri-er channel an) gui)e it through the un)ersluice. Theconstruction of the /ain weir an) the gui)e wall will then be carrie).

The construction of the hea)wor(s will thus be carrie) out in two stages. During the first stagethe start of the construction of a longitu)inal coffer)a/ will be constructe) in the /ain ri-er channel closing off the flow in the left ban( area. This coffer)a/ will be a,,roxi/atel 0 /long an) will ha-e a height of a,,roxi/atel 2 /. This coffer)a/ will close off the left ban( of the channel of 'agar =hola an) the flow will be channeli9e) along the right half of the (hola.So/e exca-ation wor(s will be re>uire) along the right ban( of the (hola to ensure the safe

,assage of the 110 ear )i-ersion floo). The construction of the /ain gui)e wall se,arating theweir an) un)ersluice the left ban( wing wall locate) along the left ban( of the un)ersluice will

be gi-en ,riorit. Si/ilarl the u,strea/ ,arts of the /ain ri-er inta(e an) the un)ersluice will be constructe) while the first stage coffer)a/ is in ,lace. The construction of the secon) stagecoffer)a/ will ta(e ,lace as soon as the construction of the un)ersluice the gra-el ejector an)the /ain gui)e wall are co/,lete) an) sto,logs are ,lace) at the inlet to the /ain inta(e. Thecoffer)a/ will then be rearrange) so that it will cor)on off the area for the construction of the/ain weir across 'agar =hola. This will consist of the secon) stage )i-ersion an) will in-ol-ethe construction of the u,strea/ an) the )ownstrea/ coffer)a/s. These coffer)a/s willa,,roxi/atel ha-e a total length of *0 / in the u,strea/ ,art an) +0 / in the )ownstrea/ ,art

an) will also ha-e a height of 2 /. 'oth of these u,strea/ an) )ownstrea/ coffer)a/s will buttagainst the u,strea/ an) )ownstrea/ en)s of the /ain gui)e wall se,arating the un)ersluice an)the weir. During this stage of the )i-ersion the construction of the /ain weir an) the re/aining





,arts of the construction of the inta(e inclu)ing the abut/ent wall on the right ban( will ta(e ,lace. During the secon) stage )i-ersion the entire ri-er flow will ,ass through the un)er sluice.

12+5+? Main Ri*er :nta/e, "nderslui%e and the )mer#en%y !pillway

The exca-ation wor(s for the inta(e the /ain gui)e wall the un)ersluice an) the gra-el ejector will all start )uring the first stage of the )i-ersion. The longitu)inal coffer)a/ will cut off theflow in 'agar =hola longitu)inall lea-ing sufficient s,ace in the (hola channel for the )r?wetseason flows.

As soon as the exca-ation wor( is co/,lete) the construction of the gui)e wall the left ban( abut/ent walls the /ain ri-er inta(e the gra-el tra, the un)ersluice etc. will be co//ence).The o-erall construction ,erio) for the inta(e the weir an) other surroun)ing structures

inclu)ing the un)ersluice the gra-el ejector an) the e/ergenc s,illwa will be a,,roxi/atelnine /onths.

12+5+. 9eir

The construction of the weir will co//ence )uring the secon) stage )i-ersion i//e)iatelafter the co/,letion of the first stage )i-ersion. The first stage coffer)a/ will be )is/antle) an)rearrange) so that the area for the construction of the weir is free fro/ the flow fro/ 'agar =hola. The )r?wet season flow will be allowe) to flow through the un)ersluice. The water le-el

is ex,ecte) to rise so/e 1 /eters fro/ the ri-er be) )uring the secon) stage )i-ersion. Thechannel allowing the flow into the un)ersluice an) the gra-el ejector will nee) to be wi)ene).

nitiall the exca-ation will be carrie) out to the foun)ation le-el of the weir. The ,re,aratorwor(s such as stone soling an) the PCC laer will then be carrie) out. The concrete laers will

be coor)inate) u, to the a,ex of the weir. The construction of the right ban( abut/ent wall willalso be carrie) out si/ultaneousl. The o-erall construction of the 20 / wi)e weir inclu)ing theun)ersluice an) the gra-el ejector will be a,,roxi/atel nine /onths.

12+5+4 8esander and Flushin# stru%ture

The )esan)ing basin will consist of a single / wi)e basin the effecti-e length of which will be* /. The basin will ha-e flushing con)uits with botto/ wi)th of 1.0 / an) a trans-erse slo,eof 1 in 1 on both the si)es. The longitu)inal slo,e of the flushing channel will follow theto,ogra,h along the length of the flushing channel. The single flushing con)uit will be ,lace)at the en) of the )esan)ing basin to ensure co/,lete flushing of the basins.

The construction of the )esan)er will start with the exca-ation wor(s i//e)iatel after theco/,letion of the access roa) an) /obili9ation. #nce the exca-ation is co/,lete the concretewor(s will start. The )esan)er will be finishe) off with the installation of the )ownstrea/ gatesan) the bac(filling wor(s. The o-erall construction of the )esan)er will ta(e a little o-er /onths.





12+5+6 Foreay

The construction of the foreba will be carrie) out along with the construction of the )esan)er as

it is essentiall an extension of the )esan)er. The construction of the foreba will be co//ence)as soon as the /obili9ation of the ,roject is starte). The exca-ation will be followe) b the ,re,aration of the foun)ation laer. The /ain walls of the foreba will be constructe) of concrete. The will be constructe) in tan)e/ with the construction of the )esan)er walls. Thetotal esti/ate) )uration that will be re>uire) for the construction of the foreba will be about */onths. This inclu)es the construction of its interface with the )esan)ing basin an) the inlet tothe surface ,enstoc( ,i,e connecte) to the 'agar =hola ,owerhouse.

12+5+- Colle%tion Chamer

A collection cha/ber has been ,ro-i)e) i//e)iatel )ownstrea/ of the 'agar =hola

Powerhouse. This collection cha/ber will ser-e as the collection of water fro/ the ,owerhouseof "74P an) the ,owerhouse of 'agar =hola ,owerhouse an) )ischarging it into the hea)racetunnel.

As with the other structures in the hea)wor(s co/,lex the construction of this structure willalso co//ence with the /obili9ation of the ci-il wor(s an) will start off with its o-erbur)en

exca-ation. The foun)ation ,re,aration an) concreting will follow with a,,ro,riate ,ro-isionsfor its interconnections with the inlets fro/ the cut an) co-er box cul-ert an) the tailrace of 'agar =hola ,owerhouse.

Since the collection cha/ber is connecte) to the inlet ,ortal to the hea)race tunnel this area willfro/ one of the faces of the tunnel exca-ation. t is therefore en-isage) after the exca-ationwor(s for this structure is co/,lete) this area will be use) for the exca-ation of the tunnel. Theconcreting an) other finishing wor(s for this structure will be co/,lete) onl after the all thewor(s in the hea)race tunnel en-isage) to be carrie) out fro/ this face are ter/inate). Thereforealthough the exca-ation for this structure is co//ence) with the /obili9ation of the ci-il wor(sit will be co/,lete) onl after the co/,letion of the wor(s ,ro,ose) to be co/,lete) fro/ thisface of the tunnel.

12+5+10 Cut and Co*er o( Cul*ert

A,art fro/ the hea)wor(s arrange/ent at 'agar =hola the co/,lex will also consist of a cutan) co-er box cul-ert ,ro,ose) to be constructe) across 'agar =hola.

The construction of the cut an) co-er box cul-ert will also re>uire so/e )i-ersion )uringconstruction. This will be )one in conjunction with the )i-ersion of flows for the construction of the hea)wor(s. The (hola will be channeli9e) along the right ban( an) the construction of thecut an) co-er box cul-ert ling along the /ain (hola flow area as well the length ling along theleft ban( will be co/,lete). #nce the /ain ,art of the box cul-ert is co/,lete) the (hola will

be allowe) to flow o-er the box cul-ert an) its ,rotection laer abo-e it an) the construction of the structures locate) on the right ban( will be carrie) out.

As /entione) abo-e since the flows in 'agar =hola are co/,arati-el >uite s/all the)i-ersion wor(s is en-isage) to be relati-el si/,le. t is assu/e) that channeli9ing the flows





towar)s one si)e of the (hola with the hel, of si/,le coffer)a/s will be sufficient enough to)ewater the area. xca-ation of the ri-erbe) /aterial for the cut an) co-er box cul-ert willco//ence as soon as the flows are )i-erte) along the right ban(. #nce the exca-ation is

co/,lete) the construction of the box cul-ert structure will ta(e ,lace. The construction of the box cul-ert will also inclu)e the ,rotection /easures. The o-erall construction of the cut an)co-er box cul-ert will re>uire a ,erio) of a,,roxi/atel 10 /onths.

12+5+11'dit Tunnels

Since the hea)race tunnel is consi)erabl long three a)it tunnels ha-e been ,ro,ose) for theexca-ation of the hea)race tunnel. The a)it tunnels will be *.0 / in )ia/eter an) a,,roxi/atel1; 21 an) 10 / long. The thir) a)it tunnel will be locate) towar)s the botto/ of thesurgetan(. The thir) a)it has been ,ro-i)e) so that the exca-ation of the hea)race tunnel an)surgetan( can be carrie) out se,aratel an) in)e,en)entl. The exca-ations for these tunnels will

co//ence as soon as the access roa) is in ,lace. t is en-isage) that the tunnel exca-ation willstart towar)s the beginning of the secon) ear. A ,erio) of a,,roxi/atel * /onths will bere>uire) for the construction of these a)it tunnels.

12+5+12 $eadra%e Tunnel Outlet Portal

The hea)race tunnel outlet ,ortal will be locate) a,,roxi/atel 1*0 / )ownstrea/ fro/ thesurgetan(. This outlet will for/ one of the faces for the exca-ation of the hea)race tunnel. Thethir) a)it tunnel will be use) for the exca-ation of the surgetan(.

The construction of this outlet ,ortal will co//ence as soon as the access roa) is in ,lace. 8ithan o-erbur)en -olu/e of al/ost 11000 /* an) a roc( -olu/e of a,,roxi/atel 1+*00 /* it isen-isage) that the o,en cut exca-ation for the outlet ,ortal will re>uire a ,erio) of at least 12/onths.

12+5+1 $eadra%e Tunnel

The hea)race tunnel has a finishe) )ia/eter of *.+ / an) will be concrete line). The total lengthof the tunnel fro/ the inta(e u, to the surgetan( will be +:*< /. The tunnel will be exca-ate)fro/ six wor( faces. The /axi/u/ length of exca-ation fro/ one face will thus be about ;00/. Drill an) blast /etho) will be use) for the exca-ation of the tunnel. The tunnel exca-ationwill be carrie) out using )rilling ju/bo while )u/, truc(s an) wheel loa)ers will be use) for /uc(ing. The tunnel will ha-e ,i,elines for -entilation )ewatering co/,resse) air su,,l ina))ition to the low -oltage ,ower su,,l for lighting -ent fan ,u/,ing. The antici,ate)

,rogress rate of tunnelling is 1. / ,er )a ,er face. The tunnel will be concrete line). Thetunnel exca-ation is en-isage) to be co/,lete) o-er a ,erio) of 2+ /onths which inclu)es

,ro-ision of shotcreting as well. t will be starte) towar)s the en) of the fourth ear after the

outlet ,ortals an) the three a)it tunnels are co/,lete).





12+5+15 !ur#e Tan/

The surge shaft has a finishe) )ia/eter of < / an) a height of *< /. The surge tan( is o,en at

the to, so an access roa) will be ,ro-i)e) to the to, ,ortion. Drill an) blast /etho) will be use)for the exca-ation. 7uc(ing in the u,,er ,ortion will be carrie) out fro/ the to, while that of the lower ,ortion will be carrie) out through the botto/ si)e using A)it !o. *. The ,ilot shaftwill be exca-ate) fro/ the botto/ using a raise) boring an) subse>uentl full )ia/eter exca-ation will be carrie) out in the lower ,ortion. Finall concrete lining will be ,ro-i)e) inthe shaft fro/ the botto/ to the to, ,ortion. xca-ation will be co/,lete) o-er a ,erio) of 1/onths while concrete lining will re>uire a ,erio) of 12 /onths.

12+5+1? !ur7a%e Pensto%/

The construction of the *< / long steel ,enstoc( ,i,e with a )ia/eter of 2.+ / will re>uire a

,erio) of a,,roxi/atel 12 /onths. The construction of the anchor bloc(s will be starte)si/ultaneousl after the co/,letion of exca-ations wor(s at its s,ecifie) locations. Theconstruction of all anchor bloc(s an) sa))le bloc(s will i//e)iatel be followe) b the ,lacingof the surface ,enstoc( ,i,es inclu)ing the ex,ansion joints an) other bearing /aterial.

12+5+1. 8rop!ha7t

The 0o incline) shaft has a finishe) )ia/eter of 2.+ / an) a length of 22* /. The ,re%re>uisitefor this acti-it is the exca-ation of the high ,ressure tunnel. The incline) shaft will beexca-ate) in the botto/ to to, /anner using raise) cli/ber. The incline) shaft will be full

line) with concrete of 0.* / thic(ness in a))ition to roc( bolt an) shotcrete su,,ort. xca-ationis esti/ate) to re>uire a ,erio) of nine /onths while lining will re>uire a ,erio) of another six/onths.

12+5+14 $i#h Pressure Tunnel

The high ,ressure tunnel has a total length of 110 /. The whole of the high ,ressure tunnel will be steel line). The ,ressure tunnel will be exca-ate) fro/ the ,ortal ,ro-i)e) b the exca-ationof the ,owerhouse b )rilling an) blasting /etho) si/ilar to that of the hea)race tunnel. Steelliner will be /a)e fro/ ,enstoc( sections wel)e) at the site an) concrete lining of the *0 c/

thic(ness will be ,ro-i)e) in the ,ressure tunnel. t is esti/ate) that the ,ressure tunnelexca-ation an) co/,letion of the wor( will re>uire a ,erio) of a,,roxi/atel four /onths.

12+5+16 Powerhouse

The surface ,owerhouse has a )i/ension of 1 / x +* / x 22 / The ,owerhouse will housetwo -ertical axis ,elton turbines generators an) ancillar e>ui,/ent for control an) ,rotection.

The exca-ation of the ,owerhouse will be carrie) out through a benching ,roce)ure. Theco/,letion of the exca-ation will be followe) b foun)ation ,re,aration wor(s an) theconcreting of the foun)ation an) the substructure. A,,ro,riate bloc( outs will be left for the

,lace/ents of the e/be))e) ,arts for the foun)ation an) the o-erall ,lace/ent of the ,eltonturbines an) other generating an) ancillar e>ui,/ent. The su,erstructure inclu)ing the colu/nssu,,orting the o-erhea) crane inclu)ing the se,aration walls will be constructe) with structural





concrete. The construction of the ci-il wor(s for the ,owerhouse is ex,ecte) to ta(e so/e */onths. t is en-isage) that roc( exca-ation will re>uire the longest ,erio).

12+5+1- Tailra%e Pond and Outlet !tru%ture

The tailrace of $,,er "ahughat =hola 4)roelectric Project will consist of a tailrace ,on)locate) i//e)iatel )ownstrea/ of the two units in the ,owerhouse an) an outlet structure thatallows the )ischarge to flow bac( into the (hola. The construction of the tailrace channel will becarrie) out in a con-entional /anner. xca-ation wor(s will be carrie) out along with theexca-ation of the ,owerhouse. The concreting of the channel will also be carrie) out in ,arallelto the construction of the ,owerhouse. The o-erall construction of the tailrace will be co/,lete)with the co/,letion of the ,owerhouse.

12+5+20 )le%troMe%hani%al )Guipment

The ,re,aration of the )esign an) s,ecification ten)ering an) awar)ing /anufacturingforwar)ing an) the installation of the electro /echanical e>ui,/ent will re>uire a ,erio) of atleast *< /onths.

12+5+21 !wit%hyard

An out)oor switchar) will be locate) at an a,,roxi/ate ele-ation of 1*00. t will be locate)well abo-e the location of the ,owerhouse at a relati-el higher location )ue to lac( of s,ace inthe -icinit of the ,owerhouse. The switchar) will be 0 / in length an) +0 / in wi)th. Theswitchar) will also nee) significant roc( exca-ation the )uration of which will be about 12

/onth.

12+5+22 Testin# and Commissionin#

This acti-it will re>uire a ,erio) of two /onths. t shall co/,rise of wet testing an) generationtesting.

12+5+2 Con%lusions

t is en-isage) that the ,roject will be i/,le/ente) un)er stan)ar) '# contract ,roce)ures.The ,re,arator acti-ities li(e A arrange/ent an) construction of site roa) u,gra)ing of existing roa)s construction of ,ower an) ca/, facilities shoul) be ta(en u, on a ,riorit basis.So/e acti-ities in these tas(s coul) be )one in ,arallel. The total ti/e )uration re>uire) for theactual ci-il wor(s construction after the start of the /obili9ation is esti/ate) to be * /onths.The ,re,arator wor(s inclu)ing es,eciall the 20 (/ long access roa) is ex,ecte) to re>uire a

,erio) of * /onths. The total )uration fro/ the start of the )etaile) engineering u, to theco//issioning of the two units will re>uire a total ,erio) of a,,roxi/atel :2 /onths. Theconstruction sche)ule is shown in Figure 12.1.





Fi#ure 1224 Constru%tion !%hedule




Upper Rahughat Hydroelectric Project *aseline)n"iron$ental Study

1+0 '!):N) )NV:RONM)NT' !T"8A <:))=

1+1 >eneral

$,,er "ahughat 4)roelectric Project is situate) i//e)iatel a)jacent to an) in between twoh)ro,ower ,rojectsY "ahughatE7angale 4)roelectric Project at the u,strea/ si)e an)"ahughat 4)ro,ower Project being constructe) b !A at the )ownstrea/ si)e. The ,rojectsite lies between latitu)es of 2;02;J*0K an) 2;02J+ !orth an) between longitu)es ;*0*1J0Kan) ;*0*0J00K ast.

As ,er n-iron/ent Protection "ules 1<<: it is legall bin)ing for a ,roject of this si9e to carrout an stu). As ,er the P" 1<<: Bnliste) in Sche)ule%1 Pertaining to "ule * an) itsa/en)/ent ga9ette) on Februar 2 200< an stu) has to be carrie) out for a h)ro,ower

,roject ha-ing a ca,acit fro/ 178 to 078.

The To" for of the ,ro,ose) ,roject was a,,ro-e) on 20:?0<?2 fro/ the 7inistr of

nerg. This stu) is -ali) for electricit generation onl an) )oes not inclu)e the trans/issionline. The ,ro,ose) ,roject )oes not lie in an of the national ,ar(s conser-ation areas wil)lifesanctuaries or in an of the en-iron/entall an) sociall sensiti-e areas. Since the ,ro,ose)

,roject has an installe) ca,acit of +;. 78 onl an stu) nee)s to be carrie) out for the ,roject.

Tun)i Power Co/,an BP-t. Lt). is the ,ro,onent of $,,er "ahughat 4)roelectric Project.The ,ro,onent is a ,ri-ate sector h)ro,ower )e-elo,er of !e,al. The ,ro,onent is res,onsiblefor generating the electricit an) trans/iting it u, to the !e,al lectrict Authorit owne)substation at 7ag)i District. The ,ro,onent has entruste) A,ex nerg BP. Lt).to carr out thefeasibilit an) en-iron/ental stu)ies of the ,ro,ose) ,roject.

The ,roject ,ro,onent has obtaine) a sur-e license of installe) ca,acit 2<. 78 BAnnexE1fro/ the 7inistr of nerg to carr out the technical an) en-iron/ental stu). The license wasissue) on 20?0*?0 'S an) its -ali)it ,erio) has been exten)e) u, to 20;?0*?0+ 'S.

The Detaile) fiel) in-estigation for the stu) was carrie) out fro/ 2 th 7a to 2n) A,ril2011B20;?02?12 to 20;?02?1< to collect the baseline infor/ation on ,hsical biologicalsocio%econo/ic an) cultural en-iron/ent. !ow the )raft re,ort is un)er ,re,aration.Following shows the content of the )raft re,ort un)er ,re,aration.

1+2 >eneral :ntrodu%tion o7 the Pro&e%t


Chapter Thirteen

'!):N) )NV:RONM)NT' !T"8A <:))=




The ,ro,ose) ,roject is locate) in Chi/(hola B,rdv6Fn6 Dagna/ Bug6d Pa(ha,ani

B6v66gL an) 3hi BemL 5DCs of 7ag)i District 8estern De-elo,/ent "egion of

!e,al.Chi/(hola an) Dagna/ 5DCs are locate) along the left ban( of "ahughat =hola whereasPa(ha,ani an) 3hi 5DCs area locate) along the right ban(. The tunnel inlet site is ,ro,ose) onthe left ban( of 'agar(hola BChi/(hola 5DC%+ about 10/ u,strea/ fro/ the confluence of "ahughat "i-er an) 'agar =hola. The ,owerhouse is ,ro,ose) on the left ban( of "ahughat"i-er at Lagar/a of Dagna/ 5DC%. ' location the ,roject is situate) i//e)iatel a)jacentto an) in between two h)ro,ower ,rojects na/el "ahughat 7angale 4)roelectric ProjectB1.;78 at u,strea/ si)e an) !A owne) "ahughat 4)ro,ower Project B*0 78 at the)ownstrea/ si)e. Following the o,ti/i9ation stu) the ,roject has been )esigne) with aninstalle) ca,acit of +;.78 Bhowe-er the sur-e license has been grante) for 2<.; 78 onl.

t will generate 2;+.+1&8h of energ anuall. The esti/ate) ,roject cost is "s. *.;** /illion$SN inclu)ing the cost of ci-il an) electro/echanical wor(s but exclu)ing the cost of thetrans/ission line.

The ,ro,ose) ,roject )oes not ha-e a /otorable access roa) at ,resent. The nearest roa) hea) tothis ,roject is an earthen roa) that originates fro/ &aleshwor an) reaches =ha,si)an)a. Thisroa) is (/ long. &aleswhor lies about * (/ north of 'eni on the 'eni%3o/song roa). 'eni the)istrict hea)>uarter of 7ag)i )istrict is accessible b a 1* (/ long gra-el roa) that originatesfro/ 7al)hunga on Po(hara%'aglung 4ighwa.

About 20 (/ of access roa) will be re>uire) to reach the hea)wor(s site fro/ the nearest roa)

hea) at =ha,si)an)a BDagna/ 5DC. 4owe-er if the access roa) u, to the hea)wor(s site of the "ahughat 4)roelectric Project being i/,le/ente) b !A is built earlier onl about 2 (/of access roa) will nee) to be built to reach the ,owerhouse site of the ,ro,ose) ,roject.Si/ilarl a,,roxi/atel ;(/ of ,roject roa) will also be re>uire) for this ,roject.

The ,roject will re>uire 2*.2 ha of lan) for construction ,ur,oses. The lan) use ,attern for theconstruction ,ur,ose of this ,roject consists of forest B.01 ha culti-ate) lan) B.11 ha an)

barren lan) B12. ha. The nu/ber of wor(force re>uire) for the ,roject construction isesti/ate) to be 20 ,ersons. #f the total B20 wor(force 1: ,ersons will be selecte) fro/ thelocal area. The actual construction ,erio) of the ,roject is esti/ate) to be :2 /onths. Thus the

,roject is en-isage) to be co/,lete) b the en) of 201 if construction wor( is co//ence) bthe beginning of 2012.

1+ 8ata ReGuirement and !tudy Methodolo#y

The baseline infor/ation was collecte) on ,hsical biological an) socio%econo/ic an) culturalen-iron/ent of the ,roject area. The /eteorological )ata such as air water te/,eraturehu/i)it lan) use ,attern an) other infor/ation concerning ,hsical en-iron/ent of the ,rojectarea was collecte) as secon)ar infor/ation )uring the )es( stu).

Consi)ering the co/,onents of the ,roject the total stu) area of the ,roject is )i-i)e) into twocategories Core Project Area an) Surroun)ing Area. The ter/ ,roject in)icates the

,ro,ose) $,,er "ahughat 4)roelectric Project an) area inclu)e) the core ,roject area an)surroun)ing area. The ter/ ,roject area is also referre) to as stu) area for .





A tea/ of /ulti%)isci,linar ex,erts -isite) the ,roject site fro/ 2 th 7a to 2n) A,ril2011B20;?02?12 to 20;?02?1< to collect the baseline infor/ation on ,hsical biological

socio%econo/ic an) cultural en-iron/ent. Si/ilarl secon)ar infor/ation was obtaine) fro/

the re-iew of literature an) other /aterial relate) to the ,roject area. After the ,re,aration of the)raft re,ort as ,er the P" 1<<: a fifteen )as ,ublic notice will be ,ublishe) in national)ail re>uesting for suggestions fro/ the concerne) 5DCs local ,eo,le schools sub%health

,ost an) co//unit forest users grou, an) other local sta(ehol)ers on the ,otential i/,acts )ueto the i/,le/entation of the ,roject.

The )raft re,orts along with a co-ering letters will be sent to the concerne) local an) )istrictle-el go-ern/ent offices for re-iew an) suggestions. n this regar) res,onses are to be obtaine)

fro/ )ifferent sta(ehol)ers about the re,ort. Public /eetings with ,roject affecte) ,eo,lean) other sta(ehol)ers are to be con)ucte) in the ,roject affecte) 5DC. The sta(ehol)ers are to

be gi-en o,,ortunities to ,ut forwar) their i)eas an) concerns in relation to the re,ortthrough a ,ublic relation officer. "eco//en)ation letters fro/ the ,roject affecte) 5DC an)co//unit forest offices will be collecte) an) incor,orate) in the re,ort.

1+5 Re*iew o7 Plans;Poli%ies, '%ts, Rules, Re#ulations, >uidelines, !trate#ies, Manuals

and Con*entions

As ,er the /an)ator ,ro-ision set forth in the P" 1<<: an extensi-e re-iew of rele-ant PlansActs "ules Policies &ui)elines Con-entions Strategies an) Stan)ar)s ha-e been )one )uring

the ,re,aration of the re,ort.

1+? 8es%ription o7 the )(istin# )n*ironment

1+?+1 Physi%al )n*ironment

1+?+1+1 Topo#raphy

"ahughat =hola the tributar of =ali &an)a(i "i-er flows fro/ the north to the south. Thealtitu)e of the terrain -aries fro/ 1:0.; /asl to 11:<.; /asl. The to,ogra,h is generallfa-ourable for the i/,le/entation of a h)ro,ower ,roject.

1+?+1+2 Climate and $ydrolo#y

The a-erage /axi/u/ an) /ini/u/ te/,eratures of 7ag)i )istrict is *:.1 0C an) *.10Cres,ecti-el. Si/ilarl the a-erage /axi/u/ an) /ini/u/ rainfall of 7ag)i )istrict is+0:// an) 2<// res,ecti-el. Cli/atic con)itions of "ahughat =hola watershe) area -arwith altitu)e. The lower catch/ent below ele-ation 2000/asl has a te/,erate an) also war/cli/atewith the region. The ,roject area ex,eriences wet cli/ate )uring 3une to Se,te/ber an)col) cli/ate )uring !o-e/ber to A,ril.

1+?+1+ 9atershed

The ,roject area is locate) in &an)a(i "i-er 'asin watershe) area. The to,ogra,h of the ,roject area shows /i))le /ountainous lan)for/s with -aring ele-ation. The "ahughat =hola





flows north%south fro/ the 4igh 4i/alaan "ange through )ee,l incise) gorges. The"ahughat =hola originates fro/ the Dhaulagiri range an) its catch/ent area is /ountainouswith a wi)e -ariation in ele-ations ranging fro/ ;1: / BDhaulagiri Pea( an) 100/ at the

weir site.

1+?+1+5 !lope !taility and and !lide

Slo,e stabilit of the ,roject area is such that the left ban( of "ahughat =hola is relati-elstable co/,are) to the right ban(. Large scale lan)sli)es B200/2 are ,resent along the right

ban( o,,osite to the location of Chi/(hola 5illage. A /o)erate lan)sli)e was also obser-e)further )ownstrea/ of the ,ro,ose) ,owerhouse site.

Few s/aller lan)sli)es were seen to exist along the cree(s aroun) Dagna/ an) Asi/a 5illagearea which is the area of the location of the ,owerhouse. "elati-el big lan)sli)es are attribute)to an unfa-orable relation between the be)roc( foliation an) the natural slo,e of the groun).

1+?+1+? >eolo#y

The ,roject area is locate) in Lesser 4i/alaan $nit. The /ain roc( t,es foun) in the ,rojectarea are ,hllite an) >uart9ite belonging to =unchha For/ation an) Fagfog uart9iteres,ecti-el /entione) b Stoc(lin an) 'hattarai elsewhere in the literatures on geolog of

!e,al 4i/alaas.

Towar)s the )ownstrea/ area near 'u(ula 5illage highl Bcube jointe)%crushe) /o)eratel tohighl weathere) )ar(%blac( slate is ,resent an) these can also be seen along the roa) cuts.Fre>uent lan)sli)es are foun) to occur in this area an) it is attribute) to ,oor roc( /ass >ualit.n general the be)roc( )i,s towar)s the u,strea/ )irection an) the /ain un)ergroun) structuresof the ,roject which is the hea)race tunnel will ha-e a fa-orable orientation with res,ect to the/ain )iscontinuit orientation. The hea)race tunnel will be exca-ate) al/ost ,er,en)icular tothe stri(e of the foliation ,lane.

xce,t for the in-erte) si,hon an) the weir across 'agar =hola all of the structures will belocate) on the left ban( of 'agar =hola an) will be foun)e) on the allu-ial )e,osit ,resent in thearea. The allu-ial )e,osit is /a)e u, of strong big boul)ers of gneiss >uart9ite an) schist etc

inclu)ing silt an) can thus be )escribe) as coarse graine) boul)er /ixe) soil%silt gra-el. The/axi/u/ si9e of the boul)er is /easure) to be about /. The inta(e weir across 'agar =holaas well as the ,owerhouse will howe-er be exca-ate) an) foun)e) ,artl on allu-ial an) ,arton collu-ial )e,osit. The thic(ness of the collu-ial )e,osit has been esti/ate) to be about :/.

1+?+2 iolo#i%al )n*ironment

1+?+2+1 Forest and Ve#etation

The ,ro,ose) ,roject area is characteri9e) b sub%tro,ical to te/,erate ecological 9one. The ,roject area co-ers ,ri-ate an) co//unit forests. The ,ro,ose) ,roject will affect 2

co//unit forests na/el =a/i(hor Co//unit Forest an) Chi/(hola "aniban Co//unitForest.The tunnel inlet is locate) in Chi/(hola "aniban Co//unit Forest at SisneriChi/(hola 5DC%+.The /ajor tree s,ecies of the area are $tis B Alnus nepalensis Tuni BToona

Ciliata an) =aulo B Persea odoratissima. Si/ilarl the /ajor shrub an) herb s,ecies in the





area are &hunguro B Pyrancaltha crenulata) 3ina/a)ro &ul)ung BViburnum nervosum ChhutroB Berberis asiatica) Allo BGirardina palmata Shar(ull Sisnu BUrtuca dioica a/ongst /an.

The /ajor floras of the area are $tis B Alnus nepalensis Tuni BToona Ciliata =aulo B Persea

odoratissima 'ilaune B Maesa chisia 7alato B Macaranga indica #(har B Juglans regiaPatle =atush BCastonopsis hystri Chilaune B!chima "allichi Sallo B Pinus roburghiiTushare B #ebregeasia salici$olia =o,,a B %icus auriculata) an) Du)hilo B %icus neri$olia.

The ,ro,ose) foreba is locate) at Dagna/ 5DC% the ,lace is locall calle) $,allo Al)i(a.The foreba location is a culti-ate) lan) with scattere) in)i-i)uals of $tis B Alnus nepalensis"an(uli Chilaune B!chima "allicii an) Du)hilo B %icus neri$olia.

The ,enstoc( ,asses through ,ri-ate forest an) culti-ate) lan) on to the ,owerhouse locationwhere the )o/inant s,ecies are Sallo B Pinus roburghii Chilaune BSchi/a wallichii $tisB Alnus nepalnensis Dar B Boehmeria rugulosa an) 'ilaune B Maesa chisia.

The ,lant s,ecies of ethno%botanical i/,ortance in the ,roject area are Tite,ati &Artimesia

vulgaris)' Sallo BPinus roxburghii &urans B (hododendron spp)' etc. Si/ilarl ,lant s,eciesli(e Chutro B Berberis asiatica)'Sallo BPinus roxburghii #(har B3uglans regia Pa(han-e)B Bergenia ciliate 'o(e Ti/ur B *anthoylum armatum) ha-e /e)icinal -alue.

!o ,art of the ,ro,ose) ,roject falls in national ,ar( en-iron/entall sensiti-e area wil)lifesanctuar buffer 9one an) conser-ation area.

1+?+2+2 9ildli7e

The )i-ersit in the terrain /a(es a )i-erse habitat in the ,roject area that su,,orts a wi)e rangeof ani/als. The ani/als re,orte) in the area are "atuwa 7riga B Muntiacus munt+a,)' ChituwaB Panthera pardus)' Du/shi B -ystri indica)' Seto%'an)ar B Presbytis entellus "ato%'an)ar B Macaca mulata)' Chari 'agh &Prionailurus bengalensis)' Sal &Canis aureus)' 7alsa,roB Martin $lavigula)' !auri &-erpestis ed"ardsi)' 'agh &Panthera tigris)' 'halu &!elenarctos

tibetanus)' and 'an 'iralo &%eli chaus)

1+?+2+ '*ian Fauna

The bir) s,ecies recor)e) in the ,roject area are 'an =hu(hura BGallus gallus)' 'hangeraB Passer domesticus)' 'ha(ura BTurdoides s,s. Chil B A.uila heliacal)' Dhu((ur &!treptopelia

chinensis)' &aunthali &Apus a$$inis)' 3ureli &Pycnonotus ca$er)' =ag BCrovus splendens)'

=alchu)a B Myiophonus caeruleus)' =alij &/ophura leucomelana)' 7aina &Acridotheses $uscus)'

and !il(antha &Coracias benghalensis)

1+?+2+5 'Guati% Fauna

The fish s,ecies foun) in the "ahughat =hola are Asala B!chi0othoraichthys sps =abre

BGlyptothora trilineatus an) =hu(huri 'ene.





1+?+2+? Rare endan#ered and prote%ted spe%ies o7 Flora and Fauna

5egetations li(e #(har B Juglans regia are ,rotecte) ,lant s,ecies of !e,al. A-ian faunas li(e

Chil BA>uila heliacal an) 3ureli B Pycnonotus ca$er are ,rotecte) bir)s of !e,al. Se-eralwil)life s,ecies of the ,roject area are liste) in CTS% an) an) hence re>uire high concernfor ,rotection )uring an) after construction.

1+?+ !o%ioe%onomi% and Cultural )n*ironment

1+?++1 V8C Pro7ile

Population %hara%teristi%s

The ,ro,ose) ,roject area co-ers + 5DCs na/el Chi/(hola Dagna/ Pa(ha,ani an) 3hin.Accor)ing to the !ational Census 2001 the total ,o,ulation of the ,roject affecte) 5DCs is:01* with a /ale ,o,ulation consisting of *21: B+.<O an) a fe/ale ,o,ulation consisting of *:< B+.1*O. The ,o,ulation of the ,roject area co-ers .12:O of the )istrict ,o,ulationB11+++:. The a-erage ,o,ulation )ensit of the ,roject affecte) 5DCs is high B.11

,ersons?s>. (/ as co/,are) to the )istrict a-erage of 0 ,ersons?s>.(/. Si/ilarl the totalnu/ber of househol)s an) a-erage househol)s si9e are 1:0 an) +.+: res,ecti-el.

The /ajorit of the ,o,ulation is 7agar B:.1;O followe) b =a/i B;.:1O an) Chhantel

B:.;O. !e,ali B;<.2O is the wi)el s,o(en language in the ,roject area. The other s,o(enlanguages are Chhantel B:.;<O 7agar B2.;1O an) others B0.0+O.

The a-erage literac rate B,o,ulation ears an) abo-e of the ,roject area is O with a /aleliterac rate of .O an) a fe/ale literac rate of +.+O Bthe )istrict literac rate is .:O witha /ale literac rate of :.;O an) a fe/ale literac rate of +.O.

About :+O of the ,o,ulation in the ,roject area is econo/icall acti-e. The ,ercentageco/,osition of econo/icall acti-e fe/ale ,o,ulation is higher B:.:O than the /ale

,o,ulation B:2.1O.

The econo/ic acti-it in the ,roject area is low. #nl .2O of the househol)s in the ,rojectaffecte) 5DCs are engage) in econo/ic acti-it. The econo/ic acti-it is /ostl characteri9e)

b /anufacturing tra)e?business ser-ice an) trans,ort an) other. The ,ercentage co/,ositionof tra)e an) business sector is higher B**.O followe) b ser-ice B2.<O /anufacturingB11.+O trans,ort B0.<O an) other B2.<O.

'#ri%ulture

$, lan) BPa(ho 'ari is the )o/inant culti-ate) lan) in the ,roject area. t co-ers <0.O of thetotal culti-ate) lan). #nl <.O of the culti-ate) lan) is categori9e) as =het. #ut of the totalculti-ate) lan) B1+ha onl +1ha B2.+O of lan) has ear roun) irrigation facilit. Theirrigation sste/ is being /anage) b the local ,eo,le. 7ost of the househol)s culti-ate their own lan) an) -er little culti-ate others. The lan) transaction is not ,ractice) in the ,roject area.7ai9e rice /illet an) wheat are the /ain cro,s grown in the ,roject area.

Tundi Power Company %ea(ii,ity &tudy




About 1.:O of the househol)s in the ,roject area ha-e agriculture lan) onl. Si/ilarl about+;.;O of the househol)s ha-e their own culti-ate) lan) with li-estoc( an) ,oultr.

$istori%al, Reli#ious and 'r%heolo#i%al !ite

There is a hot water ,on) BTato,ani =un)a in Dar/ija of Dagna/ 5DC%:. Peo,le fro/neighbouring 5DCs li(e Chi/(hola Pa(ha,ani 3hin an) =uhine 7angale gather for the fete

B7ela which is organi9e) fro/ Februar to 7a of each ear. Si/ilarl there are 'hu/e ThanBTe/,le locate) in each 5DC of the ,roject area. There is a Church in =hola,ari -illage of Chi/(hola 5DC%1. A cre/ator site is also locate) in Lewang Puchhar of Chi/(hola 5DC%1.This site is being use) b the local 4in)u co//unit of Chi/(hola 5DC.

!ettlement Pattern

The /ain settle/ents of the ,roject area are Chi/(hola Dar/ija 3hin an) Pa(ha,ani. 7ost of the houses are constructe) using /u) stones an) woo). "oofs are /ostl /a)e u, of slates an)gal-ani9e) sheets. 7igration in search of job is co//on in the settle/ents of the ,rojectaffecte) 5DCs. 7an /ale ,eo,le fro/ 7agar co//unit are re,orte) to be wor(ing in then)ian an) 'ritish ar/. #thers /igrate te/,oraril to =ath/an)u Po(hara 'utwal e-en toArab countries an) 7alasia to see( e/,lo/ent.

)le%tri%ity

Till )ate onl 22O of the total ,o,ulation ha-e been benefite) b the electricit facilit in7ag)i )istrict. Tato,ani S/all 4)roelectric Plant with a ca,acit of 2 78 is the onl ,ower

,roject of this )istrict. The ,ower centre is integrate) in the !ational &ri) Sste/ an) ,ro-i)es aser-ice to a ,o,ulation of 2;:+ B12O of the 1+ 5DCs BThere is a total of +0 5DCs in 7ag)i.Peltric sets solar ,anels bio gas ,lants an) so/e other /icro%h)ro electric centres ,ro-i)eelectricit to the general ,ublic in the )istrict. The ,roject affecte) 5DCs are not ,ro-i)e) withelectricit through the national gri).

8rin/in# water and !anitation !ituation

Pi,e) water su,,l s,ring an) strea/ are the sources of )rin(ing water. =u/bha =hola is the/ain source of )rin(ing water in Dagna/ 5DC. So/e of the houses are e>ui,,e) with toiletfacilities in the ,roject affecte) 5DCs. 4eart )iseases asth/a tuberculosis an) )iabetics areso/e of the co//on )iseases that were note) )uring the fiel) -isit.

1+. )n*ironmental :mpa%t

1+.+1 ene7i%ial :mpa%t

The i/,le/entation of this h)ro,ower ,roject will to so/e extent lea) towar)s the creation of

econo/ic )e-elo,/ent o,,ortunities in the 8estern De-elo,/ent "egion. The /ain areas of benefit )uring the construction ,erio) will be the o,ening u, of the area to /ar(et forces goo)/obilit an) the creation of jobs. The region will benefit initiall )uring the :2 /onthsconstruction ,erio) through the creation of aroun) 20 e/,lo/ent o,,ortunities for local





,eo,le an) the secon)ar )e/an) for goo)s an) ser-ices to be su,,lie) to all as,ects of the ,roject. Peo,lesH )e/an)s for goo)s an) ser-ices ten) to change with change in -olu/e. 8iththe rise in inco/e the ten)enc of the ,eo,le to loo( for better >ualit goo)s an) ser-ices will

also increase thereb facilitating the /ar(et for external su,,liers an) retailers which in turn ,ro-i)e ex,osure to larger /ar(et forces. There will be econo/ic s,in offs in the ,roject i/,actarea.

#-erall the region is ex,ecte) to enjo econo/ic benefits fro/ the i/,le/entation of the ,roject in such fiel) as e/,lo/ent o,,ortunities a-ailabilit of ,ower /ar(et facilitates for local

,ro)ucts flow of goo)s an) ser-ices roa) access an) o,,ortunit to enhance -arious s(ills.Due to eas accessibilit better /ar(et o,,ortunities an) rural electrification econo/ic

acti-ities /a still continue in this area. Further/ore )ue to the construction of 20 (/ of newaccess roa) the existing touris/ in)ustr /a flourish. 8ith the construction of this ,roject the)istrict will recei-e /ore re-enue which can be utili9e) in -arious acti-ities such as ruralelectrification /icro an) ,eltric set /il( chilling centre rural roa)s )rin(ing water wo/ene/,ower/ent ,rogra/s etc. The i/,act is ex,ecte) to be high long ter/ an) regional.

1+.+2 'd*erse :mpa%t

1+.+2+1 Physi%al

'+ Constru%tion Phase

Topo#aphy, land use and landta/e

A total of 2*.2 ha of lan) will be ac>uire) b the ,roject ,ro,onent for )ifferent ,rojectstructures an) facilities. #ut of the total lan) 10.2 ha will be ac>uire) ,er/anentl an) 1* hawill be ac>uire) for te/,orar use )uring the ,roject construction. The lan) use ,attern for construction ,ur,ose are forest B.01 ha culti-ate) lan) B.11 ha an) barren lan) B12. ha.Lan) use changes will /ostl occurr along the tunnel inlet /uc( )is,osal site ca/, site >uarrsite ,owerhouse an) the sites for other /ajor ,roject structures. All lan) to be ac>uire) or use)falls in the Chi/(hola an) Dagna/ 5DCs. The ,er/anent lan) use change is li(el to result in a

,er/anent loss of ,ro)uction resources base ,articularl of the culti-ate) lan) co//unit

forest an) ,ri-ate forest. 4owe-er the ,roject will also ac>uire 12. ha of barren lan) for the)is,osal site.

'ir Guality, noise and *iration

The i/,act on a/bient air >ualit will be generate) fro/ acti-ities such as blasting >uarringexca-ation site clearance /uc( )is,osal e/ission fro/ -ehicles an) construction e>ui,/entswhich will generate fugiti-e )ust ,articulate /atter carbon /onoxi)e oxi)es of nitrogen an)sul,hur )ioxi)e. The fugiti-e )ust ,ollution will be /ore acute )uring the )r season co/,are)to the wet /onths in the construction ,hase

Ri*er morpholo#y

Tundi Power Company " %ea(ii,ity &tudy




Construction /aterials a-ailable in 'agar =hola will be use) an) a te/,orar ,roject roa) willalso be built on the floo) ,lain. 4ence the ri-er /or,holog is also li(el to be change) )uringthe construction ,erio).

9ater Euality

The nu/ber of wor(ers will increase )uring the ,ea( construction ,erio). ncrease) nu/ber of wor(force in a li/ite) area will li(el in)uce sewerage )is,osal ,roble/. n -iew of existingwater >ualit of "ahughat =hola this a))itional waste /a accelerate ,ollution of ri-er water

,articularl )uring the )r season. Though the )uration is short /agnitu)e of the i/,act isconsi)ere) to be /e)iu/ an) the extent will be local. 'esi)es this so/e sanitation wastes fro/labor ca/,s are li(el to ,ollute the water /icrobiologicall an) a)) inorganic ele/ents li(ecarbon nitrogen an) ,hos,horous.

ea/a#e o7 oil and #rease and other liGuid materials

A nu/ber of light an) hea- -ehicles will be re>uire) for the construction of the ,roject. These-ehicles will use )iesel an) ,etrol engine oil bra(e oil etc. There will be a li(el i/,act )ue tolea(age of oil an) grease an) other /aterials. The oil if s,ille) will easil s,rea) o-er the groun)

,ro)ucing ,otential ,ollution ha9ar)s. The oil s,ill ,ollutes the water surface an) the )issol-e)oxgen content of the strea/ water /ight be re)uce). + Operation Phase

Topo#raphy, land use and land ta/e

The /ajor ,roject structures fall on the barren an) culti-ate) lan)s. The exca-ation wor( re>uire) for the ,roject construction lea)s to the change in the existing to,ogra,h. The

,er/anent ac>uisition of lan) for tunnel inlet ,owerhouse roa) an) ,i,e align/ent etc causesthe change in lan)sca,e.

Ri*er morpholo#y and draina#e

Di-ersion of water )uring the lean flow ,erio) is li(el to create )ewatere) 9one fro/ tunnelinlet to the tailrace which coul) lea) to the change in the ri-er /or,holog. The )rainage ,attern

at the -icinit of the ,roject area is unli(el to change.!poil handlin# and disposal

The ,er/anent ,resence of s,oil ban(s will create ris(s of scour un)er floo) con)itions thatexcee) the )esign assu/,tions an) safet factors. This /a result in su))en influx of roc(gra-el an) se)i/ent to the ri-er water that will trans,ort this /aterial )own the ri-er course witha)-erse i/,acts on water >ualit an) fish. The i/,act is ex,ecte) to be /o)erate in /agnitu)esite s,ecific an) of short )uration.

:mpa%t on mi%ro%limate in redu%ed 7low one in d;s and impoundment area in u;s

The )i-ersion of flow will e-entuall result in so/e i/,acts on u,strea/ an) )ownstrea//icrocli/ate. The low -olu/e of water to the )ownstrea/ )uring the )r season /a cause





)eficienc of water to so/e a>uatic life. Si/ilarl change in the )issol-e) oxgen le-el )ue tolow -olu/e of water will also create )ifficulties for a>uatic ,o,ulation.

1+.+2+2 iolo#i%al


Forest Resour%es

The esti/ate) area of forest loss )ue to the construction wor( alone is .01 hectare B+.< ha of co//unit forest an) 0.0 ha of ,ri-ate forest. Due to the i/,le/entation of ,roject there will

be a loss of ;+ ,lants B`10 c/ D'4 of )ifferent s,ecies. #f the total ,lant loss ,ole class an)ti/ber si9e class constitute +* an) 20* res,ecti-el. Si/ilarl there will be loss of :1see)lings an) +< sa,lings in the ,roject area.

9ildli7e

The /ajor sources of i/,act to the wil)life an) their habitat )uring the construction ,erio) is)ue to the high inflow of wor(ers their /o-e/ent their ca/, sites ,ossible illegal hunting

,ractices blasting an) exca-ation )is,osal all of which can (ill frighten or )is,lace thewil)life.

Again the /ajor i/,act )ue to the ,ro,ose) ,roject in o,eration will be of in)uce) t,e. Theincrease) acti-ities in the -icinit of the ,roject area /a fa-or illegal hunting an) ,oaching.

4ence the i/,act )uring the o,eration of the ,ro,ose) ,roject ,ri/aril )ue to the in)uce)acti-ities will be in)irect low significance local an) long ter/.

Fish and other aGuati% li7e

The li(el i/,act on fish ,o,ulation will be )ue to the )i-ersion of water that will increase theacti-it in the ri-er. 'ecause the water flow in the ri-er will not be re)uce) before it goes intoo,eration. This i/,act will be low local an) long ter/ in nature. A/,hibian s,ecies #wntB /utra lutra will be -ulnerable in all the stages of wor( in the ,roject.

C+ Operation Phase

Forest Resour%es

The forest resources )e,letion is li(el to occur )ue to /uc( an) s,oil )is,osal )isturbances tonatural slo,es )uring construction of canal which /a in)uce slo,e failure in future. Thein)uce) acti-ities such as restaurants hotels cottage in)ustries are li(el to exert ,ressure onforest an) e-entuall )e,lete the forest resources.

9ildli7e

The increase) acti-ities in the -icinit of the ,roject area /a fa-or illegal hunting an) ,oaching.

Fish

Tundi Power Company 1$ %ea(ii,ity &tudy




The )ownstrea/ section of low flow along the ri-er channel will greatl ha/,er regular fish/o-e/ent. The u,strea/ as well as )ownstrea/ fish co/,osition will be greatl altere) )ue to

the low flow in the )ownstrea/ reaches. The i/,act is high local an) long ter/ in nature.

1+.+2+ !o%ioe%onomi% and Cultural )n*ironment


oss o7 a#ri%ultural land

The total culti-ate) lan) to be affecte) )ue to the i/,le/entation of the ,roject is .11 ha B*.0

ha of te/,orar lan) an) *.11 ha of ,er/anent lan). 4owe-er altogether 2* househol)s willlose *.11 ha of culti-ate) lan) ,er/anentl.

The a/ount of culti-ate) lan) nee)e) for the ,roject i/,le/entation is 2.;O of the total lan)B2*.2 ha. 7oreo-er the total culti-ate) lan) a-ailable in ,roject affecte) 5DCs is ::0 ha.4ence the loss of lan) )ue to ,roject construction is onl 0.0+O.

oss o7 house and other properties

Altogether houses belonging to househol)s will be affecte) )ue to the i/,le/entation of the ,roject. All affecte) houses are of (achchi t,e. 4owe-er none of the other t,es of structures

will be affecte) )ue to the i/,le/entation of the ,roject. !one of the co//unit structures will be affecte) )ue to the i/,le/entation of the ,roject.

oss o7 %rop produ%tion

The total ,ro)uction loss )ue to the ,roject i/,le/entation in .11 ha of lan) is 1:.<+7TB*:.0*2 7T of ,er/anent loss an) 1+.0* 7T of te/,orar loss.

Puli% $ealth and !anitation

ncrease in outsi)erHs influence )uring construction ,hase is li(el to a)) further stress on thelocal health an) sanitation situation. Pollution of lan) water an) air )ue to constructionacti-ities causes i/,act on the health to the local co//unit.

9ater !upply

8ith the increase in ,o,ulation along with the construction acti-ities a ,otential )ecline of theaccess to the )rin(ing water an) existing sanitation con)ition will occur in the ,roject area. Theo-erall i/,act on water su,,l an) sanitar situation will be the shortage of )rin(ing waterincrease) ,ressure on the existing water su,,l sste/ increase) )istance to the safe )rin(ingwater increase in )isease -ectors an) re)uce) water >ualit )ue to increase) sanitation

,roble/s etc.!o%ial, Cultural and Reli#ious Pra%ti%e





There are so/e li(el i/,acts es,eciall the a)-erse ones that are /ost li(el to occur on thesocial structures nor/s an) cultural ,ractices of the co//unities locate) close to theconstruction area. During the ,roject construction the influence of the outsi)e wor(force on the

local wa of life an) tra)itional cultural ,ractice can result into cultural erosion un)esire) social ,ractices )is,utes conflicts an) ,ossible )ilution of social bon)s a/ong the local ,eo,le.

!o%ial !er*i%e Fa%ilities

De/olition of social ser-ice facilities an) infrastructures such as schools health ,osts water su,,l ,i,es ta,s an) wells an) others will not be re>uire) for site clearance. 4ence thisi/,act will occur in the ,roject area. 'ut the wor(force of the ,roject will re>uire thee)ucational facilities for their chil)ren if the sta with the/ for a long ti/e. n this case

,ressure on the local schools will be increase) as the local schools are run with li/ite)resources. Si/ilarl the construction wor( an) relate) influx of ,o,ulation in the ,roject area

will /a(e the existing institutions regar)ing health water su,,l teleco//unication electricitetc. unable to )eli-er the re>uire) le-el of ser-ice. 'esi)es existing /ar(et an) hotels will co/eun)er ,ressure.

aw and Order !ituation

The acci)ents in-ol-ing local ,eo,le an) structure ha-e alwas been sensiti-e issues )uring theconstruction ,hase of a ,roject often lea)ing to wor( bloc(a)e. An acci)ents in-ol-ing theconstruction wor(ers are ,otential to generate conflict between the contractor an) wor(ers witha)-erse i/,act on the construction wor( ,rogress.

O%%upational $ealth and !a7ety

na,,ro,riate was of construction an) fault )esigns can be the cause of acci)ents a/ong the ,roject wor(ers. The acci)ents can ha,,en )ue to the lac( of (nowle)ge training use of safettools etc.

>ender and Vulnerale #roup

7ajorit of the /en of the ,roject area are li(el to be in-ol-e) in the construction acti-itiescreating shortage of labor re>uire) for agricultural an) other househol) acti-ities. The shortage/a ha-e to be fulfille) b wo/en an) chil)ren. This will gi-e the/ a))itional bur)en of wor(loa). 4owe-er use of chil) labor is legall ,rohibite) in !e,al.

Rural )%onomy due to :n%reased )%onomi% '%ti*ities

Project acti-ities create so/e sort of e/,lo/ent o,,ortunities an) use of local resourceswhich su,,ort the rural econo/. Such acti-ities that float so/e /one locall can lea) to

inflation in the local /ar(et. Such i/,act is howe-er low with regar)s to the si9e of the ,rojectan) the origin of wor(force.

+ Operation Phase





Peoples eha*ior due to stoppa#e o7 %ash 7low

During the o,eration ,hase as the nu/ber of hire) labor force with)raws fro/ the site alongwith the su))en )eclining of cash flow in the local area the local ,eo,le will ha-e little sourceof cash inco/e whereas their s,en)ing ten)enc will re/ain the sa/e as it was )uring theconstruction ,hase. The therefore /a suffer a su))en financial )e,ression.

9ithdrawal o7 e%onomi% a%ti*ities and employment

First an) fore/ost i/,act of o,eration ,hase is the with)rawal of econo/ic acti-ities thatflourishe) )uring the construction ,hase. As /ost of the construction relate) wor(force lea-e the

,roject area the facilities an) /ar(ets )e-elo,e) to /eet their )e/an) will fin) the/sel-es)is,lace) with low -olu/e of /one flow an) less econo/ic growth.

8isturan%e due to permanent stru%tures

Due to the ,resence of ,er/anent structures of tunnel inlet ,enstoc( ,i,e surge tan( ,owerhouse etc there can be crossing o-er of )isturbance to both locals an) wil)life. Si/ilarlfar/ing hin)rance occurs while ,loughing the agro%fiel)s if the ,er/anent structures are ,lace)at the /i))le of an fiel) boun)aries.

Visual :mpa%t

The /ajor -isual i/,act on the lan)sca,e )ue to the ,resence of ,roject structures will occur in ,roject area. The i/,act cannot be /itigate).

o%al )%onomy

8hen construction wor(s will be co/,lete) al/ost all of the wor(ers will lea-e the area exce,ta few staff an) wor(ers re>uire) for the o,eration of the ,roject. This su))en fall in the nu/ber

of ,eo,le will )ecrease )e/an)s for co//o)ities )ra/aticall. 7ar(et for local ,ro)uces will be lost. 7an local ,eo,le will be out of wor(. All these will )ecrease inco/e of local ,eo,lese-erel )ue to loss of business jobs an) /ar(et. The su))en )ecline of econo/ic acti-ities /alea) to )e,ression a/ong local ,eo,le.

:mpa%t on mo*ement and sa7ety o7 peoples and wildli7e due to sudden release o7 water d;s

o7 dam in lean season

Chil)ren /a go for swi//ing local ,eo,le /a cross the ri-er an) fisher/en /a go for fishing in "ahughat =hola. The /a not be aware about the su))en release of water fro/ thehea)wor(s area. t is therefore en-isione) that acci)ents /ight occur often )uring the su))en

release of water.





1+4 'lternati*e analysis

An alternati-e analsis of the ,ro,ose) ,roject has been carrie) out base) on ,roject locationan) )esign. The t,e of turbines an) thereb the si9e of the ,owerhouse were )eter/ine) on the

basis of the )esign )ischarge an) rate) hea).

Due to the "ahgughat 7angale 4P in the u,strea/ ,art of the ri-er $,,er "ahughat4)ro,ower Project can be )e-elo,e) in two was one as an in)e,en)ent ,ower ,roject with anin)e,en)ent hea)wor(s structure along the "ahughat =hola an) the secon) as a casca)e of "ahughat 7angale 4P. #n this basis the alternati-e arrange/ents consi)ere) for the ,rojectare as follows.

1+4+1 8esi#n 'lternati*e

1+4+1+1 Cas%ade de*elopment

f $,,er "ahughat 4P is )e-elo,e) as an in)e,en)ent ,roject a se,arate hea)wor(s structurewith a )esan)er will ha-e to be built across "ahughat =hola so/ewhere )ownstrea/ of theconfluence of "ahughat an) 'agar =hola. Since there is a ,ossibilit of using the )ischargefro/ the tailrace of "ahughat 7angale 4P buil)ing a se,arate hea)wor(s structure woul)result in unnecessar extra costs.

Further/ore o,ting for the first wa of )e-elo,/ent woul) result in the loss of hea) that exists between the ,ro,ose) ,owerhouse of "ahughat 7angale 4P an) the su,,ose) location of thehea)wor(s of $,,er "ahughat 4P if it were built.

Alternati-el the secon) wa to )e-elo, the ,roject woul) be to )i-ert the tail water of "ahughat 7angale 4P into the hea)race tunnel of $,,er "ahughat 4P b constructing aninterconnection sste/ at the ,owerhouse of "ahughat 7angale 4P at 'agar =hola. Thissche/e will not re>uire the construction of a se,arate hea)wor(s an) )esan)ing basin. 4owe-erin or)er to collect the )ischarge fro/ 'agar =hola a s/all )i-ersion weir an inta(e an) a)esan)er will be nee)e) at 'agar =hola u,strea/ fro/ the ,owerhouse of "ahughat 7angale4P. The )ischarge fro/ 'agar =hola will be a))e) to the )ischarge fro/ "ahughat 7angale inthe collection cha/ber an) then con-ee) to the hea)race tunnel of the ,roject.

t is >uite ob-ious fro/ the abo-e argu/ents that the secon) alternati-e is /uch /ore attracti-ein ter/s of cost as well as benefits. The secon) alternati-e was therefore consi)ere) for the)esign of the ,roject.

The onl )rawbac( of this sche/e is that the $,,er "ahuhgat 4P cannot be co//issione) ,rior to the co//issioning of "ahughat 7angale 4P.

1+4+1+2 Power #eneration 7rom a#ar Khola

The )ecision to ta, the flow fro/ 'agar =hola for ,ower generation re>uires the construction of a )i-ersion weir with a )esan)er. 'agar =hola at this location is fairl stee, an) will re>uire

,ro/inent energ )issi,ation structures to con-e the flow fro/ the )esan)er to the collectioncha/ber before it is con-ee) to the hea)race tunnel. The )ifference in hea) a/ounts to so/e1/.





o%ation 'lternati*e

The ,roject will consist of hea)wor(s structures locate) at the confluence of "ahughat =hola

an) 'agar =hola. The ,ro,ose) hea)wor(s structure for $,,er "ahughat 4P basicall consistsof structures interconnecting the tailrace of "ahughat 7angale 4P a ri-er )i-ersion structure a)esan)er an) a s/all ,owerhouse for 'agar =hola in the inta(e for u,,er "ahuhgat 4P. Thetail water fro/ "ahughat 7angale 4P is ,ro,ose) to be brought across 'agar =hola site to itsleft ban( si)e with the ,ro-ision of a cut an) co-er box cul-ert structure. The )ischarge fro/'agar =hola will also be )i-erte) with the ,ro-ision of a s/all weir across the =hola as well asa )esan)er an) a ,owerhouse for ,ower generation before being )i-erte) into a collectioncha/ber locate) just before the inta(e ,ortal for the hea)race tunnel of $,,er "ahughat 4P.

n case of $,,er "ahughat 4P se-eral conce,tual co/,arisons were /a)e regar)ing thea,,ro,riate choice for the con-eance. The terrain along the ,ro,ose) align/ent for the

con-eance fro/ the hea)wor(s u, to the 'agar =hola hea)wor(s is >uite stee, an) unsuitablefor an o,en canal. An un)ergroun) tunnel has thus been ,ro,ose) for this ,art of the align/ent.

"egar)ing the location of ,owerhouse the ,ossibilit of locating it along the left ban( of "ahughat =hola was also stu)ie). $n)ergroun) ,owerhouse is onl consi)ere) when no suitableareas are a-ailable for the location of a surface ,owerhouse. A surface ,owerhouse has thus been

,ro,ose) for this ,roject.

No '%tion 'lternati*e

This alternati-e a-oi)s the i/,le/entation of the ,roject. This alternati-e has beneficial as wellas a)-erse i/,acts. Do nothing alternati-e will conser-e so/e of the en-iron/ental a)-ersei/,acts at the cost of continuit of ,o-ert in the region.

No Forest Option

!o forest o,tion for the ,ro,ose) ,roject was also anal9e) so as to alter the location of ,rojectco/,onents such that /ini/u/ forest woul) be )isturbe). The currentl selecte) tunnel inletlocation tunnel surge tan( ,enstoc( an) ,owerhouse are the /ost suitable.

1+6 Miti#ation and )nhan%ement Measures

1+6+1 )nhan%ement Measures

The construction of the ,ro,ose) ,roject will ,ro-i)e the local co//unities an) the regionitself with nu/erous o,,ortunities for socio%econo/ic )e-elo,/ent. The ,ro,ose)enhance/ent /easures inclu)e technical an) s(ill orient training local co//unit )e-elo,/ent

,rogra//e inco/e generating e)ucation lea)ershi, )e-elo,/ent training to i/,ro-e the ,ositi-e attitu)e towar)s the ,roject i/,le/entation training on intensi-e ,ro)ucti-it of agricultural acti-ities an) fresh -egetable en-iron/ental awareness ,rogra/ Binclu)ing healthsanitation safet etc. The technical training inclu)es ,lu/bing /echanical training account

(ee,ing house wiring etc. Si/ilarl s(ill orient training inclu)es off season -egetable far/ingani/al rearing installation of bio%gas sste/ i/,ro-e) sto-e B!udharia,o Chulo) herbsi)entification collection an) far/ing sste/ touris/ relate) training li(e tre((ing hotel/anage/ent etc. Local resources will be use) to execute the enhance/ent ,rogra//es. The





,roject affecte) 5DCs will recei-e /ost of the benefits fro/ the ,roject. /,acts of the roaltgrowth social e>uit an) en-iron/ental justice woul) be /onitore) regularl.

1+6+1+1 Physi%al )n*ironment


Topo#raphy, landuse and land ta/e

Fertile agricultural lan) is -er li/ite) in the ,roject i/,act area. Therefore efforts will be/a)e to /ini/i9e the ,er/anent an) te/,orar lan) ta(e )uring the construction ,erio).8here-er ,ossible lower -alue ,ro)uction lan) will be utili9e) for ,roject facilities in

,reference to higher -alue lan).

'ir Euality

"egular chec(ing an) /aintenance of the e>ui,/ents will be carrie) out which will lower thegaseous ,ollutants li(e carbon /onoxi)e oxi)es of nitrogen lea) etc. Si/ilarl regular s,rin(ling of water on ,roject construction sites will also be carrie) out to re)uce the fugiti-e)ust e/ission. C& sheets will be use) to ,rotect so/e sensiti-e sites. 7as(s will be ,ro-i)e)for those wor(ers who wor( in crusher ,lant an) other )ust areas. 'roa) leaf local an)e-ergreen s,ecies ,lants will be ,lante) near the ca/, site an) office as )ust screens or arrester.

Noise and *iration

ar ,rotection e>ui,/ent will be ,ro-i)e) to the o,erators an) wor(ers who o,erate the/achines such as co/,ressors crushing ,lants roc( )rilling /achines an) concrete roc(

brea(ers which usuall e/it /ore than ; )' noise le-els at a )istance of / or less.Pro-isions will be /a)e to use light e>ui,/ent less ex,losi-es /aterials an) to control blastingto /ini/i9e the -ibration as /uch as ,ossible. All -ehicles ,ling in the construction area will

be /aintaine) regularl as ,er the /anufactureHs reco//en)ations.

$ydrolo#y and Ri*er morpholo#y

Acti-ities within the ri-er be) such as construction of )i-ersion weir extraction of construction/aterial etc will ha-e so/e i/,acts on ri-er /or,holog. The ri-er be) will be (e,t as in

,re-ious con)ition. Si/ilarl the construction of the )i-ersion weir will be ,lanne) in such awa that concentrate) flow or the )i-erte) flow )oes not /a(e ban( erosion as such.

9ater Guality

Possibilit of water >ualit )eterioration fro/ sanitation wastes an) other inorganic ele/entswill be /ini/i9e). All rubbish an) sewerage )is,osal will be (e,t well awa fro/ the anwatercourses to a-oi) conta/ination through see,age or )irect runoff. uarr sites an) gra-el

,lants will be built in such a wa that there is no )irect runoff to watercourses.

:mpa%t on stru%tures and houses due to *iration and %onstru%tion a%ti*ities





Pre%/onitoring of structures in the close ,roxi/it of the construction area will be /a)e in ,resence of the owner of the structures. n )oing so it will be /ore easier to )ealt with the/ if i/,act is foun) on the structuresY blasting acti-ities will be a-oi)e) )uring night ti/eY a

co/,ensation will be ,ro-i)e) or re,airing of structure will be )one if an )a/age occurs )ueto blasting acti-itiesY blasting acti-ities will be a-oi)e) near the slo,e structures ha-ing crac(e)an) unstable roc( cliffY local ,eo,le will be infor/e) about the sche)ule of blasting to ,re-ent

,robable acci)ents.

!to%/pilin# o7 %onstru%tion materials and disposal o7 spoils

S,oil )is,osal will not be thrown in the strea/ an) it will be safel )e,osite) in the )esignate)area awa fro/ water bo)ies. This area will be reclai/e) using bioengineering treat/ents. Thelease) area will be ,ro,erl le-ele) an) reclai/e) for re%use an) restore) to original sha,e as far as ,ossible. Pits an) latrines will be /a)e at labor ca/,s which are essential to re)uce the

,ossible i/,acts create) b the i/,ro,er )is,osal of soli) wastes. Construction /aterial such asunuse) concrete an) gra-el woul) be )is,ose) in unstable roa) si)es. The )eco/,osable wastesgenerate) fro/ the ca/,s woul) be )u/,e) in a confine) ,it /aintaine) within the ,re/ises.

Potential landslide and draina#e pattern

A )rainage ,lan will be )e-elo,e) for safe ,assage of the strea/ water e-en )uring the rainseason without causing erosion in the )is,osal site. A ,eri,heral )rainage sste/ aroun) the

,owerhouse will be constructe) to tra, surface run off an) )ischarge in safe ,lace. The hill si)eof the ,owerhouse will be ,ro-i)e) with catch )rains to ta, surface runoff that woul) otherwise

be a ,roble/ to the ,owerhouse buil)ing. Slo,e ,rotection structures such as re-et/ent walls inthe for/ of gabion walls chec( )a/s retaining walls benches or terraces ri,ra, an) s,urs will

be built at a,,ro,riate locations in or)er to retain unstable soil /asses es,eciall at the )is,osalareas an) along the critical areas along the ,roject an) access roa).

Operation o7 Guarry site

#nl two sites ha-e been i)entifie) for >uarr site in the tunnel inlet location along the 'agar =hola an) the other at =aligan)a(i "i-er an) "ahughat =hola confluence. After co/,letion of

the ,roject the >uarr site will be bac(fille) an) will be re%-egetate) b ,lanting the fastgrowing local ,lants. The erosion an) )rainage ,attern will be ,re-ente) b constructing the)rain ,i,es or causewas where necessar. 7asonr wall will be constructe) to /ini/i9e theaesthetic as,ect fro/ the /ain access roa).

Mu%/ disposal

Slo,e surface will be ,ro,erl ,rotecte) against erosion with ,articular reference to fills near thetributaries ensuring in ,articular that sus,en)e) se)i/ents )o not increase )uring )r seasonwhen turbi)it is low.

+ Operation Phase

During this stage the following /itigation /easures will be i/,le/ente) to /itigate thei/,acts





Ri*er Morpholo#y and 8raina#e

The )ownstrea/ release for the )riest /onth 7arch at the inta(e site will be 0.+:/*

?s.

!poil handlin# and disposal

S,oil )is,osal sites will be rehabilitate) b using suitable bio%engineering /easures where-er feasible u, to the ,oint in ti/e when a -egetation co-er can be classifie) as ,er/anent.

!lope staility

'ioengineering wor(s will be carrie) out to stabili9e the construction site ,articularl inaccess?,roject roa) construction.

1+- iolo#i%al )n*ironment


Forest and Ve#etation

The loss of forest lan) belongs to co//unit an) ,ri-ate forests. This loss is ine-itable as it is a ,art of site clearance. The )irect an) significant i/,act on forest loss can neither be ,re-ente)nor correcte) an) hence will be co/,ensate). The co/,ensation for the loss of ;+ ,lants isesti/ate) to be "s. <0+;1.12 B-alue of ti/ber loss will a,,roxi/atel be "s. ;1210Y -alue of fuel woo) loss will a,,roxi/atel be "s.1:02+<.0; an) the -alue of fo))er loss will

a,,roxi/atel be "s.221:1.:+.

The total area for ,lantation wor( will be 1;.0 ha. Si/ilarl for this ,ur,ose :<* ,lants will be ,lante) in +.< ha of lan). The nurser )e-elo,/ent cost for 2;;; see)lings is calculate)to be "s. 102:1<. The regular ins,ection an) /aintenance of the ,lantation wor( will becarrie) out b ,roject itself. For this ,ur,ose one [4eraloHBwatch/an will be a,,ointe) for ears at the rate "s. 000?/onth.

The ,roject will )iscourage the construction of huts?houses for the laboures using the local forest ,ro)ucts. The ,roject will (ee, recor)s about the energ use) b the construction wor(ers an))ocu/ent it in the /onitoring re,orts. t will also instruct the contractor to )iscontinue wor(ersHser-ice in-ol-e) in illegal collection an) sale of forest ,ro)ucts. !ecessar bu)get for this

,ur,ose will be allocate) )uring the construction ,erio) ta(ing note of the total energre>uire/ent of the construction wor(ers an) the ,roject staffs.

9ildli7e

Conser-ation an) en-iron/ental awareness ,rogra/s will be gi-en to staff an) wor(force. Localwor(force who will be /e/bers of local CF$&s will act as regulators. S,ecial instruction an)training will be ,ro-i)e) to the entire wor(force for not to in)ulge in the acti-ities that ,ro/otesloss of wil)life. Prohibition will be /a)e on wil)life hunting an) acti-ities that ,ro/ote wil)life

hunting in the ,roject area. n-iron/ental Awareness Progra/ will be launche) for the ,rojectwor(force local wo/en an) stu)ents to /ini/i9e the a)-erse i/,acts on the local fauna. n the ,rogra/ i/,acts )ue to slash an) burn ,ractices hunting of ani/als an) bir)s an) thosein)irect i/,acts )ue to )eforestation lan)sli)es an) se)i/entation will be a))resse).

Tundi Power Company 1" %ea(ii,ity &tudy




'Guati% resour%es

Destructi-e fishing b wor(force an) technicians with a,,lication of techni>ues li(e blastingche/ical ,oisoning an) electric shoc( will be strictl restricte).The s,oil an) constructionwastes will not be )irectl )is,ose) off into the ri-er. 8ater >ualit ,rotection /easures will bea,,lie) )uring construction ,hase. The )ownstrea/ release will be ensure) b the )esign of the

,roject itself the ,roject inta(e will be )esigne) an) gate) such that the state) )ownstrea/release of 0.+:/*?sec will be /aintaine) through the si/,le o-erflow weir.

'. Operation Phase

Forest Resour%es

The ,ressure on the forest resources will be sorte) b encouraging as well as su,,orting locals b ,ro/oting alternati-e sources of fuel. Su,,ort will be ,ro-i)e) to local co//unities for ,reser-ing their forest. "egular /onitoring of ,lantation site will be )one until han) o-er to theres,ecti-e forest usersH grou,. "ehabilitation an) forestation will be )one in the >uarr site s,oil)is,osal site ,owerhouse site ,enstoc( align/ent an) ,roject roa) b en)e/ic s,ecies.

9ildli7e

Location of ,roject structures in forest area can be a ,roble/ for wil)life as well as )o/esticani/al /o-e/ent. 4ence to /ini/i9e the i/,acts of canal in ,lace co-ere) canal will be use)throughout the length of the canal align/ent.

'Guati% li7e

The ,ossibilit of water >ualit )eterioration fro/ sanitation wastes an) other inorganicele/ents will be /ini/i9e) so that )ownstrea/ settle/ent an) fish ,o,ulation )o not getsuffere) fro/ water ,ollution. The construction of water )i-ersion structures will be )esigne) soas to release a /ini/u/ of 10O of the )r season )ischarge ,lus )ischarge for water /ill to the)ownstrea/.

1+10 !o%ioe%onomi% and %ultural en*ironment

'+ Constru%tion phase

Compensation 7or a#ri%ultural land

The lan) will be ac>uire) )uring ,re%construction ,hase. The total co/,ensation for *.11 ha of culti-ate) lan) to be ac>uire) ,er/anentl is esti/ate) to be "s. 100000.

Compensation 7or leased land

About * ha of culti-ate) lan) will be ta(en on lease for :2 /onths. Co/,ensation for lease)lan) will be ,ro-i)e) to the res,ecti-e lan) owners base) on the ,ro)uction loss. $n)er this

,ro-ision the co/,ensation a/ount ,er ear for lease) lan) is esti/ate) to be "s. ;;0*1*.2+





Bcost for *:.0+ 7T of cro,s annuall. 4ence the total co/,ensation a/ount for :2 /onthsB)uring construction ,erio) onl for the loss of 1+ 7T is "s. *00+<.

Compensation 7or house and other stru%tures

Altogether houses belonging to househol)s with *1 ,eo,le will be affecte) )ue to thei/,le/entation of the ,roject. All affecte) houses are of =achchi%Pa((i t,e. About "s.*00000 has been allocate) as co/,ensation for the loss of houses.

Compensation 7or loss o7 a#ri%ulture produ%tion

There will be a loss of *;.;; 7T of agriculture ,ro)uction ,er/anentl in *.11 ha of lan). Theco/,ensation for the loss of agriculture ,ro)uction is "s. <222+.:.

Relo%ation !%heme 7or oss o7 !tru%tures

Altogether houses will be relocate). The ,roject affecte) househol)s ha-e ex,resse) their interest for -oluntar resettle/ent in the surroun)ing ,roject area Bwithin the sa/e 5DC.

Puli% $ealth and !anitation

The existing health facilit in the ,roject area is ,oor. 4ence the existing sub%health ,ost of ,roject affecte) 5DC will be su,,orte) through the /e)icine an) e>ui,/ents )uring theconstruction ,erio).

9ater supply and sanitation

xisting water su,,l sste/ will not be use) for the /anage/ent of new water su,,l sste/.The water su,,l of the ,roject area will be i/,ro-e) b installation of /ore ,i,e lines (ee,ingta,s at a regular inter-al an) b i/,ro-ing the storage of water at the source. The >uantit of )rin(ing water can be increase) b )istributing the water of existing ,erennial strea/.

!o%io%ultural and reli#ious pra%ti%e

Co)e of con)uct will be enforce) to /ini/i9e the i/,acts on socio%cultural an) religious ,ractice of 7agar an) Chhanthel co//unities. nstruction will be gi-en to all wor(ers to act inres,onsible /anner )uring an) after the wor(ing hours res,ecting the rights ,ro,erties an)

,ractices of local ,eo,leY ,rohibition of using alcohol or )rug b the ,roject staff in ca/, an)nearb -illage. The use of local wor(ers will be /axi/i9e) in or)er to /aintain the socio%cultural an) religious har/on.

!o%ial ser*i%e 7a%ility

Se,arate ,ro-ision on co//unication lighting an) coo(ing energ )rin(ing water su,,l etcwill be /a)e in the ,roject area. Si/ilarl a))itional su,,ort ,olice force if re>uire) will be/aintaine) through coor)ination with )istrict a)/inistrati-e office. Financial su,,ort to existing

Tundi Power Company 2$ %ea(ii,ity &tudy




sub%health ,ost an) schools will be ,ro-i)e). Da/age to the co//unit infrastructures such asroa)s foot trails etc. )ue to construction acti-ities will be /ini/i9e).


The ,roject will run an awareness ,rogra/ to infor/ the local ,eo,le on the effecti-e an) ti/eluse of the cash an) ,rioriti9ing nee)s. The will also be /a)e aware of the in-est/ento,,ortunities li(el to generate )ue to the ,roject an) encourage the/ to ex,loit theo,,ortunities for long ter/ inco/e source.

Rural e%onomy due to in%rease e%onomi% a%ti*ities

To /ini/i9e the i/,acts of loss of agricultural ,ro)ucts )ue to the lan) ac>uisition an) anaffect on the occu,ation will be co/,ensate) through a,,ro,riate agricultural extension

,rogra/ li-elihoo) s(ill training ,rogra/ arrange/ent of /icro%cre)it fun) to establish s/all business or cottage in)ustries etc. 7axi/u/ job o,,ortunities will be ,ro-i)e) to the local ,eo,le in a ,ru)ential /anner an) assistance will also be ,ro-i)e) to local co//unities in the ,lanning of settle/ent )e-elo,/ents through coor)ination with the local )e-elo,/ent office.

>ender and *ulnerale #roup

Training ,ac(age for inco/e generating acti-ities will be ,ro-i)e) to the ,roject affecte)wo/an hea)e) househol)s. n a))ition wo/en in-ol-e/ent ,rogra/s such as non%for/ale)ucation cottage in)ustr ,ro/otion of i/,ro-e) coo(ing sto-es safe /aternit wo/enentre,reneurshi, an) other acti-ities contributing to the wo/en e/,ower/ent will be su,,orte)

b the ,roject.

O%%upational health and sa7ety haards

The contractor will be infor/e) to a)o,t safe construction ,ractices to /ini/i9e constructionrelate) acci)ents. Post warning signs barriers an) guar)s will be installe) to restrict access of

unauthori9e) ,ersons to the construction sites. nfor/ation will be gi-en to resi)ents for ,otentiall )angerous an) acti-e objects such as blasting sites an) high -oltage lines. Safete>ui,/ent such as hel/ets boots glo-es safet glasses an) /as(s will be ,ro-i)e) for wor(ersthose wor(ing in the tunnel wor( an) other construction site.

aw and order

District Police #ffice 7ag)i will be re>ueste) to establish a te/,orar $nit Police Post inDagna/ 5DC. A strict co)e of con)uct for the wor(force will be for/ulate) an) enforce).

'+ Operation phase






Training ,rogra/s will be organi9e) ,articularl targeting s(ille) labour force willing toestablish their own entre,reneurshi, where the can utili9e their s(ills an) earn so/e /one.The training sessions will be con)ucte) at least * /onths ,rior to the ,roject co/,letion so that

the s(ille) labour force will be able to start their business i//e)iatel u,on the ter/ination of their jobs.

9ithdrawal o7 e%onomi% a%ti*ities and employment

n or)er to /ini/i9e the a)-erse i/,acts on the local econo/ in this critical con)ition an)enhance the li-ing stan)ar) of the affecte) co//unities a training ,rogra/ will be organi9e)

,articularl for s(ille) labor force willing to establish their own entre,reneurshi, where thecan utili9e their s(ill an) earn /one an) training ,ac(ages will be )e-elo,e) to suit /ajorit of the s(ille) labor force an) encourage the/ to initiate their business.

Visual impa%t

&reener will be /aintaine) b ,lantation wor( in /ajor ,roject location sites ,articularl in the ,roject roa) align/ent ,owerhouse site canal align/ent site etc. This acti-it will hel, inre)uction of -isual i/,act to so/e extent.

:mpa%t on mo*ement and sa7ety o7 peoples and wildli7e due to sudden release o7 water d;s

o7 dam in lean seasons

As a /itigation /easure a siren sste/ will be establishe) at the hea)wor(s site to /a(e awarethe )ownstrea/ ,eo,le about the ti/ing of the release of water. Si/ilarl local ,eo,le will be/a)e aware about the siren sste/.

1+11 Miti#ation, )nhan%ement and Corporate !o%ial Responsiility Costs

The total cost for ,hsical biological an) socio%econo/ic an) cultural en-iron/ental i/,act/itigation an) enhance/ent /easures is esti/ate) to be "s. 2;;+<10<.

1+12 Monitorin# Plan

The /onitoring ,lan s,ecifies the ,hsical biological an) socio%econo/ic an) culturalen-iron/ent in ter/s of ,ara/eters in)icators /etho)s sche)ule location ti/ing sa/,lingan) /easure/ent -ariables.The ,roject ,ro,onent will be res,onsible for carring out all/onitoring acti-ities as ,er /onitoring ,lans /entione) in the re,ort. 4owe-er 7inistr of nerg District Forest #ffice an) other rele-ant agencies will also be consulte) )uring

/onitoring acti-ities. The ,ro,onent has ,lanne) to /onitor the co/,liance b establishing an)n-iron/ental 7onitoring $nit B7$ within the ,roject which will ha-e the o-erallres,onsibilit of /onitoring an) re,orting.





/,act /onitoring will be use) to /easure the ,hsical biological socio%econo/ic an) culturalen-iron/ental ,ara/eters within the ,roject area )uring the ,roject construction an) o,eration

,hase.

Monitorin# Cost

The lu/, su/ /onitoring cost is esti/ate) to be !"s. 1+;000 for 2 ears.

!ummary o7 total en*ironmental %ost

The total en-iron/ental cost inclu)ing /onitoring cost of the ,ro,ose) ,roject is esti/ate) to be"s. *0**+10< which is 0.0+ O of the total ,roject cost. So/e of the acti-ities an) costs arealrea) inclu)e) in the ,roject cost an) hence such cost is not inclu)e) here.

1+1 Conl%usion

Physi%al )n*ironment

Change in lan) use ,attern will occur )ue to the location of ,roject structures. The ,ro,ose) ,roject nee)s 2*.2 ha. #f the total lan) agriculture forest an) barren lan)s constitute .11ha.01 ha an) 12.0 ha res,ecti-el.

iolo#i%al )n*ironment

'iologicall the trees shrubs an) herbs that are to be cleare) are /ostl co//on s,ecies in

fre>uenc )ensit an) abun)ance. There are ;+ trees to be cleare) fro/ co//unit an) ,ri-ateforest lan)s. Therefore a relati-el less nu/ber of trees an) -egetation is affecte) )uring theconstruction. The ,ro,ose) ,roject site is ecologicall justifie) with /ini/u/ i/,act on the

bio)i-ersit as the ,roject has been )esigne) for tunnel o,tion. The /itigation /easures ,ro,ose) to sustain an) conser-e the en-iron/ent es,eciall the floral )i-ersit is a)e>uate an)in confor/ation with the existing Acts "ules "egulations an) Policies of the !e,al&o-ern/ent.

!o%ioe%onomi% and %ultural en*ironment

The stu) on the existing en-iron/ental con)itions an) li(el a)-erse an) beneficiali/,acts of the ,ro,ose) ,roject in)icate /o)erate le-el of a)-erse i/,acts on socio%econo/ic

an) cultural en-iron/ent which are of re-ersible in nature an) can be easil /itigate) where as/o)erate to high le-el of beneficial i/,acts. Due to the i/,le/entation of the ,roject houseswill ha-e to be relocate). Si/ilarl ,roject re>uires .11 ha of culti-ate) lan) of which *.11 ha

belongs to ,er/anent ac>uisition an) * ha for lease) lan).




Upper Rahughat Hydroelectric ProjectCost )sti$ate

15+0 CO!T )!T:M'T)

15+1 >eneral

This cost re,ort )escribes the /etho)olog use) in esti/ating the ,roject cost of the +;. 78$,,er "ahughat 4)roelectric Project locate) in 7ag)i )istricts Dhaulagiri @one of 8esternDe-elo,/ent "egion of !e,al. The esti/ate) ,roject cost is base) on the >uantities esti/ate)on the basis of the feasibilit stu) of the ,roject an) its )rawings. The unit rates of )ifferentite/s are base) on existing labour an) /aterial cost at ,resent with current the 2011 le-el ,rices.

15+2 Criteria, 'ssumptions and %ost %omponents

The following criteria an) assu/,tions are the basis of the cost esti/ateAll costs are in 3une 2011 )ollars.

• For currenc con-ersion rate of exchange rate is as follows

• $S N1 V !"s :

A (e assu/,tion is that the ,roject /anage/ent an) ,rocure/ent ,olic will stress u,onco/,etiti-e bi))ing an) that go-ern/ent ,olicies will not hin)er cost%effecti-e construction.Contractors will be free to e/,lo labour fro/ !e,al an) other neighbouring countries as)ee/e) cost effecti-e.

15+ )stimatin# methodolo#y

The /ajor co/,onent brea()own for the esti/ating ,rocess is

• su,,ort facilities access roa)s an) other general ite/s• electro/echanical e>ui,/ent• /ain ci-il construction wor(s inclu)ing on%site access• ca/, an) housing acco//o)ation facilities• engineering /anage/ent a)/inistration an) other ownerHs costs• contingencies

15++1 Ci*il 9or/s

The cost esti/ate was ,re,are) with the following a,,roaches. A >uantit esti/ate re>uires these>uential execution of the following ste,s


Chapter Fourteen

CO!T )!T:M'T)




• Sub)i-ision of the total ,roject into a nu/ber of )istinct structures Bweir an) un)ersluiceinta(e hea)race tunnel box cul-ert )esan)er foreba surgetan( ,enstoc( ,owerhouse

• an) tailrace etc..

• 'rea(ing )own of structures into a nu/ber of )istinct construction tas(s or /easurable ,a ite/s. These are o-erbur)en exca-ation roc( exca-ation fill wor( concrete wor(setc..

• Calculation of the a,,ro,riate >uantit of each ite/ esti/ate) fro/ )esign )rawings as ,resente) in the stu).

• Selection of the labour /aterial an) construction e>ui,/ent resources re>uire) for allconstruction wor(.

• sti/ating the unit costs for the ,roject b using the cost of the co/bine) resources use)an) their ex,ecte) ,ro)uction rates.

• Su//ation of all the ,ro)uct of the >uantities an) the unit costs iel)s the total cost of construction.

• The su//ation with allowances for contractors ,rofit contingenc an) allowances for engineering an) /anage/ent an) ,ro-ision for ca/, facilities gi-es the total ,rojectcost.

n a,,lication of this a,,roach contractors o-erhea) an) ,rofits /ar(%u,s is a,,lie) )uring theunit rate )e-elo,/ent.

15++2 Resour%e Costs

15++2+1 aour Rates

For esti/ating ,ur,oses the labour force was sub)i-i)e) into four categories of wor(ersuns(ille) se/is(ille) s(ille) an) highl s(ille). These categories were use) to )e-elo, the unit

rates as ,er crew re>uire/ents.

Consi)ering the o-erall construction re>uire/ents for the ,roject hourl rates of labour were)e-elo,e) base) on ,re-ailing labour rates of the ,roject site. Since the ,roject site will beaccessible a-ailabilit of labour in the local area is consi)ere). The calculate) rates of wor(erson an hourl basis are as follows

• $ns(ille) labour !"s +.;; ? hr • Se/is(ille) labour !"s 2.<+ ? hr • S(ille) labour !"s ;.0 ? hr

• 4ighl s(ille) labour !"s <;.*1 ? hr





15++2+2 Constru%tion )Guipment Rate

t is ,ro,ose) that /ajor co/,onents of ci-il wor(s will be constructe) b using stan)ar)

construction /etho)s e/,loing -arious construction /achines an) e>ui,/ent as far as ,ossible. >ui,/ent o,erating an) owing cost ,er hour is referre) to fro/ si/ilar nu/ber of ,rojects which are un)er stu) b !e,al lectricit Authorit. The re,resentati-e o,erating an)owning cost of hea- e>ui,/ent an) tools are as follows.

• Ti,,er Truc( !"s 1*;*.:; ? hr • 8heel Loa)er 4P 10 !"s 2;::.; ? hr • Concrete 7ixer 0. /*?hr !"s *<0. ? hr • 'ull)o9er 4P 1 !"s *2.<* ? hr • Air Co/,ressor 10 CF7 !"s 01.0 ? hr

15++2+ Constru%tion Material

7ost of the construction /aterial inclu)ing reinforce/ent bar will ,robabl be su,,lie) an) ,rocesse) fro/ !e,al. "e>uire) a/ount of ce/ent will be su,,lie) fro/ the nearest co//ercial/ar(et Po(hara. Construction /aterial cost is a)o,te) fro/ the cit ,rice.

• T#" Steel "einforce/ent !P" ;0000 ?ton• Ce/ent !P" 1000?ton• &elatine !P" 200?(g

15++ "nit Costs

After co/bining the re>uire) resources /ix an) a,,ling the ex,ecte) crew ,ro)uction rate thetotal cost of an acti-it is calculate) an) hence the unit rate is )eri-e) fro/ the cost."e,resentati-e unit rates for ,roject construction are ,resente) in Table 1+%2.

Tale 155? "nit Rates

!+No. :tem "nit Rate "!

1 "oc( xca-ation m 1.002 #,en Cut xca-ation m *.00* Tunnel xca-ation m +:.0+ Concrete Lining in Tunnel B72 m 1<.0 Concrete Lining B72 m 12.00 Lean concrete m 10<.00: "einforce/ent B$n)ergroun) T 1;0.00

15++5 :ndire%t Costs

ach of the unit rates for the ci-il wor(s inclu)e the contractorHs o-erhea) an) ,rofit which areassu/e) to be 20O of the )irect cost. #ut of this 10 O is consi)ere) as o-erhea) an) 10 O as

,rofit in the )irect cost.





15++? Preliminary 9or/s

A su/ of $S N *.:;* /illion is ,ro-i)e) for the ,reli/inar wor(s for $,,er "ahughat 4P.

This wor( inclu)es /obili9ation an) )e/obili9ation costs. Pro-ision for construction ,ower )uring ,roject is also /a)e in this hea)ing.

15++. '%%ess Road

A total of 2; (/ of access roa) is to be constructe) for access to the hea)wor(s site an)construction sites of the ,roject. A length of 20 (/ will be constructe) for ,roject access an) ;(/ of roa) wil be constructe) within the ,roject area as ,roject roa)s. A total su/ of $S N *.2;/illion has been ,ro-isione) for the access roa).

15+5 Ci*il 9or/ Cost

The total esti/ate) cost for the ci-il wor(s for $,,er "ahughat 4P inclu)ing access roa) is$SN 2:.+; /illion. This a/ount is * O of the total 'ase Construction Cost.

15+? $ydrome%hani%al 9or/s Cost

The total a/ount re>uire) for the h)raulic steel structures such as the sto,logs gates -al-esinclu)ing steel ,enstoc( an) accessories is $S N *.1*1 /illion.

15+. )le%trome%hani%al )Guipment

The cost re>uire) for the electro/echanical e>ui,/ent was esti/ate) b a co/bination of /etho)s inclu)ing the following

• inter,retation of bu)get ,rices su,,lie) b ,otential su,,liers /ainl for the larger an)/ore ex,ensi-e e>ui,/ent such as turbines generators ,ower transfor/ers an) /aininlet -al-esY

• in%house esti/ates using establishe) international ,rices an)?or relationshi,s for /oreroutine ite/s the in%house infor/ation being base) on ears of collection of ,rice )ataan) often eli/inates the errors of -ariations of ,rices occurring )ue to abru,t changes insu,,l an) )e/an)Y

• ,ercentage of lu/, su/ ,ro-isions on a ratio basis base) on ex,erience for lesser /iscellaneous ite/sY

• in /echanical ser-ices the e/,irical relation )e-elo,e) for esti/ation inclu)es heating-entilation air con)itioning )rainage )ewatering oil storage cooling waterco/,resse) air e/be))e)?ex,ose) ,i,ing )ucts ele-ator )iesel generator /aintenancee>ui,/ent an) water le-el /easure/entsY an)





• in electrical ser-ices the e/,irical relation )e-elo,e) for esti/ation inclu)es low-oltage switching control e>ui,/ent DC sste/ e>ui,/ent sste/ transfor/ersco//unication e>ui,/ent an) station ser-ice e>ui,/ent.

The total cost for the set of two units of electro/echanical e>ui,/ents for ,ower generation at'agar =hola an) the two units of turbine%generators an) all ancillar e>ui,/ents re>uire) in the

,owerhouse of $,,er "ahughat 4P is esti/ate) to be $S N 1. /illion.

15+4 Transmission ine, !ustations and !wit%hyard

The ,ower generate) fro/ $,,er "ahughat 4P ,roject will be e-acuate) in the switchar) of the substation of "ahughat 4P B!A through a 1*2 (5 single circuit trans/ission line withACS" 'ear con)uctors on steel lattice towers. The length of the trans/ission line between$,,er "ahughat 4P an) "ahughat 4P Substation B!A is about ; (/. The total cost for theselecte) trans/ission line for $,,er "ahughat 4P is about $S N .*: /illion. The costinclu)es all necessar accessories an) line bas.

15+6 )n#ineerin# and Mana#ement Cost

A ,ro-ision of $S N +.1*0 /illion which is ; O of the total construction base cost has been/a)e for engineering an) /anage/ent inclu)ing the )etaile) engineering )esign an)su,er-ision cost.

15+- Contin#en%ies

Contingencies ha-e been a,,lie) to -arious areas of wor( to co-er costs )ue to changes in the ,hsical sco,e which cannot be i)entifie) at this stage. The following allowances will bea,,lie)

10O on ,reli/inar wor(s an) access roa)1O on all ci-il wor(

O on electro%/echanical e>ui,/ent an) trans/ission line wor(s.The following contingencies ha-e been assu/e) for $,,er "ahughat 4)roelectric Project.

Contingencies for Preli/inar an) access roa) is $S N 0.:0 /illion

Contingencies for ci-il wor( $S N *.00 /illion

4)ro/echanical electro/echanical an) trans/ission line $S N 1.20; /illion

Total ,ro-ision /a)e for contingencies $S N +.<: /illion





15+10 Resettelment and )n*ironmental Miti#ation 9or/

A,,ro,riate su/s ha-e been allocate) for en-iron/ental co/,ensation an) /itigation ,ur,oses. A ,ro-ision for the resettle/ent en-iron/ental /itigation an) /anage/ent coste>ui-alent to )S - 1.+; /illion has been /a)e for $,,er "ahughat 4P.

15+11 Owners %ost

A ,ro-ision of *O of the base cost e>ual to $S N1.+; /illion has been ,ro-i)e) as the ownerscost.

15+12 Pro&e%t Cost

The total esti/ate) ,roject costs for $,,er "ahughat 4P is $S N *.;** /illion.

The su//ar of the esti/ate) total ,roject costs for the ,roject is tabulate) below

Tale 155. !ummary o7 the Pro&e%t Cost

UPP! !"#U$#"T #%&!'LT! P!'*T

SU++"!% ', P!'*T 'ST

Serial o nstalled a.acit/ (+W) 0123

&escri.tion "mount in US 4

1 Preliinar E/$en!e! 3783200

2 cce!! *oa%! 3280000

3 +ea%ork! at agar (ola 8506644 "e!an%er an% Flu!(ing at agar (ola 427801

5 Forea at agar (ola 181326

6 #ollection #(aer at nter#onnection agar (ola 384015

7 Pen!tock Poer(ou!e Tailrace at agar (ola 675,8

8 #ut an% #o9ere% o/ #ul9ert at nter#onnection 227331

, +ea%raceTunnel 10771251

10 %it Tunnel! 1411130

11 Surge Tank ,,7611

12 Pen!tock "ro$!(aft an% +ig( Pre!!ure Tunnel 7,764,

13 Poer(ou!e 3766378

14 Tailrace Pon% an% #anal 138354

15 Sitc( ar% 384110

15 'ate! :al9e! an% Steel liner 313050,

16 Turine! 'enerator! cce!!orie! 15655000

17 Tran!i!!ion Su!tation! Sitc(ar% 5376000

T'T"L 'ST!UT' 5"S 'ST 36789:7:9;

Engineering &anageent ;8< of a!e= 41303,4

*e!ettleent an% En9ironent 3< 15488,8

>ner! co!t 3< 15488,8

T'T"L P!'*T 5"S 'ST 317131766;

#ontingencie!?

10< of Preliinar Work! an% cce!! *oa% ;1 2= 706320

15< of #i9il ork ; 3 15= 3060783





5< of Electroec(anical an% Tran!i!!ion ;15 17= 1208075

Total #ontingencie! 4,75178

$!"& T'T"L 8<71<<79:3

!'U&& $!"& T'T"L 8<71<<7===

n!talle% #a$acit ;kW= 4,000

#o!t @ kW 1303




Upper Rahughat Hydroelectric Project!isburse$ent Schedule

1?+0 8:!"R!)M)NT !C$)8")

'ase) on the construction sche)ule the following )isburse/ent sche)ule has been a)o,te) for the econo/ic e-aluation of $,,er "ahughat 4)roelectric Project.

The construction ,erio) of the ,roject has basicall been )i-i)e) into two stages. The first stageconsists of the construction of the access roa) an) other ,re,arator wor(s while the secon)stage consists of the actual construction of the ,roject. The total )uration for the construction of $,,er "ahughat 4P inclu)ing engineering an) other ,re,arator wor(s will be :2 /onths.This )uration is longer than the nor/al )uration for ,rojects of a si/ilar nature an) is /ail )ueto the costruction of the access roa) an) the re>uire/ent to construct this ,roject as a casca)e)e-elo,/ent to "ahughat 7angale 4P. The )etails are gi-en in Cha,ter 12 of this re,ort.

The first stage of the ,roject will consist of acti-ities such as the )etaile) engineering )esigninclu)ing the ,re,aration of ten)er )ocu/ents ten)ering lan) ac>uisition construction of infrastructure inclu)ing an) es,eciall the construction of the access roa) an) other initial

wor(s. This stage of the )e-elo,/ent of the ,roject can be un)erta(en in a,,roxi/atel */onths.

The actual construction of the ,roject will consist of the construction of the ci-il wor(selectro/echanical wor(s h)ro%/echanical wor(s an) the trans/ission lines. The actualconstruction of $,,er "ahughat 4P will also ta(e about * /onths res,ecti-el.

The )istribution of the ,roject cost within these ,erio)s are as shown below.

Aear 8istriution o7 Pro&e%t Cost

First ear 2 OSecon) 6ear 2 OThir) 6ear OFourth 6ear *; OFifth 6ear 2; OSixth 6ear 2 O

Due consi)eration has been gi-en to a)-ance ,a/ent for /anufacturing /obili9ation an))e/obili9ation while )i-i)ing the cash flows for each ear. The )etails of the )isburse/ent of costs of )ifferent wor( ite/s on the basis of the base cost for the two ,rojects are gi-en in Tables

1%2 an) are also )escribe) in brief in the following sections. Table 1%1 shows the )isburse/entof costs accor)ing to acti-ities.


Chapter Fi7teen

8:!"R!)M)NT !C$)8")




Tale 1?54 8isursement o7 Costs '%%ordin# to '%ti*itiesS.!o. Acti-it Percentage of the

Total Cost for "ahughat 4P

1 "esettle/ent n-iron/ental Access "oa) an) #wnerHs Cost 1: O2 Ci-il 8or(s * O* &ates 5al-es an) Steel Liner O+ Turbines an) &enerators 2: O Trans/ission Lines an) Substation ; O: ngineering an) 7anage/ent ; O

1?+1 Resettlement, !upport Fa%ilities, '%%ess Road and Preparatory 9or/s

7itigation costs ha-e been allocate) as a,,ro,riate to ta(e care of socio en-iron/ental i/,actswithin the ,roject area. !ecessar lan) ac>uisition costs ha-e been inclu)e) un)er this hea)ing.The cost for the access roa) has also been inclu)e) un)er this hea)ing. About 12 O of the total

,roject cost has been allocate) un)er this hea)ing. Since the bul( of the ex,en)itures will be inthe initial ,hases of the ,roject the total of this co/,ensation an) /itigation an) other

,re,arator wor(s will be s,ent in the first 12 /onths. So/e ,art of it will be s,rea) outthroughout the construction ,erio) for en-iron/ental /itigation /easures.

1?+2 Ci*il 9or/s

The ci-il wor(s cost co/,rises the bul( of the ,roject cost a/ounting to +1 O of the total ,roject cost. Construction of all of the ci-il structures exce,t for the access roa) will ta(e ,lace)uring the last two ears. Cost allocation for all of the ci-il co/,onents is su//ari9e) asfollows

Tale 1?56 Cost 'llo%ation 7or Ci*il Components

Project Co/,onent Percentage of Ci-il Cost

'agar =hola 4ea)wor(s +.20Desan)er an) Flushing Structure at 'agar =hola 2.10Foreba 0.<0Collection Cha/ber 1.<0Penstoc( Powerhouse an) Tailrace at 'agar =hola 0.*0Cut an) Co-er 'ox Cul-ert 1.14ea)raceTunnel 2.;0A)it Tunnels .<0Surge Tan( +.<0Penstoc( an) Dro, Shaft *.<0

Powerhouse 1;.0Tailrace Canal 0.:0Switch ar) 1.<0





1?+ >ates, Val*es and !teel ine

The h)ro /echanical ,arts consist of the s/allest largest co/,onent of the total cost of the ,roject. Along with the cost of the gates -al-es an) steel ,enstoc( this ite/ co/,rises of Oof the total cost of the ,roject cost.

1?+5 Turine and >enerator

The total cost for the ,rocure/ent an) erection of the turbine an) generator will be 2 O of thetotal ,roject cost. The erection of the turbine an) generator at the site will start towar)s the en)of the fifth ear once the ,ri/ar concrete of the ,owerhouse has been co/,lete). Theasse/bl an) finishing of the turbine an) generator ,lace/ent will be co/,lete) b the /i))leof the sixth ear of the construction.

1?+? Transmission ine and !ustation

Construction of the 1*2 (5 Trans/ission Line an) Switchar) will cost ; O of the total ,rojectcost. Construction of the trans/ission line an) substation will co//ence towar)s the en) of thefourth ear an) will be conclu)e) a,,roxi/atel before the )ate of co//issioning of the

,roject.

1?+. 8etailed )n#ineerin# and Constru%tion !uper*ision

About ; O of the construction cost has been allotte) for the engineering a)/inistration an) the/anage/ent inclu)ing the cost for construction su,er-ision for the ,roject. The )isburse/ent sche)ule for the ,rojects is gi-en in Tables 1%*.





Tale 1?5- 8isursement !%hedule 7or the Pro&e%t

S 6ear 6ear 6ear 6ear 6ear 6ear

!o Particular 1 2 * +

1 Preli/inar x,enses *0 O *0 O *0 O 10 O

2 Access "oa)s +0 O * O 2 O

* 'agar =hola 4ea)wor(s +0 O 0 O

+ Desan)er an) Flushing Structure at 'agar =hola +0 O 0 O

Foreba +0 O 0 O Collection Cha/ber +0 O 0 O

:Penstoc( Powerhouse an) Tailrace at 'agar=hola +0 O 0 O

; Cut an) Co-er 'ox Cul-ert +0 O 0 O

< 4ea)raceTunnel +0 O *0 O *0 O

10 A)it Tunnels 100 O

11 Surge Tan( +0 O +0 O 20 O

12 Penstoc( an) Dro, Shaft * O *0 O * O

1* Powerhouse +0 O +0 O 20 O

1+ Tailrace Canal 20 O ;0 O

1 Switch ar) 20 O ;0 O

1 &ates 5al-es an) Steel Liner +0 O *0 O *0 O

1: Turbines &enerators I Accessories +0 O *0 O *0 O

1;Trans/ission Substations I Switchar)lectrical +0 O *0 O *0 O

1< ngineering 7anage/ent B;O of base +0 O *0 O *0 O

20 "esettle/ent an) n-iron/ent +0 O 20 O 20 O 20 O

21 #wners cost 20 O +0 O 20 O 20 O




Upper Rahughat Hydroelectric ProjectProject )"aluation

1.+0 PRO@)CT )V'"'T:ON

1.+1 >eneral

The /ain ,ur,ose of the ,roject e-aluation is to ,ro-i)e financial infor/ation facilitating ,ricing as well as in-est/ent an) financing )ecision. t is necessar to exa/ine the ,rojectthoroughl ,rior to its i/,le/entation to ensure the )e-elo,er that the ris( is worth ta(ing.-aluation of ,roject in ter/s of financial ris( an) return is i/,ortant consi)eration for in-est/ent an) financial co//it/ent to the ,roject. At ,resent !A is a single buer of theenerg to be ,ro)uce) fro/ the ,roject. t has fixe) the seasonal rates to be ,urchase) fro/ thein)e,en)ent ,ro)ucers for the installe) ca,acit u, to 2 78. 4owe-er for the ,roject withinstalle) ca,acit excee)ing 2 78 ,ower ,urchase agree/ent will be carrie) out between the

,ro)ucer an) !A to fix the energ rate. 4ence the /ain objecti-e of the e-aluation is to attractfinancing institution for in-est/ent an) to ascertain that the ,roject is worthwhile to un)erta(efor the )e-elo,er.

1.+2 Methodolo#y

Financial analsis ta(es the -iew of the in)i-i)ual ,roject ,artici,ants. The financial costsassociate) with ,roject are base) on nor/al accounting con-entions. Thus assets are -alue) inter/s of their financing costs an) are )e,reciate) o-er their lease) ,erio).

Financial ,lanning is concerne) with the esti/ation of the financial i/,lications of a ,ro,ose))e-elo,/ent. t is base) on the use of /ar(et ,rices an) therefore inclu)es an taxes or roalties which will be le-ie) on the factors of ,ro)uction an) an subsi)ies ca,ital or o,erating which /a be recei-e) as ,art of the )e-elo,/ent. All costs are charge) an) allre-enues cre)ite) to the analsis in the actual a/ounts ex,en)e) or recei-e) an) in the case of

foreign costs con-erte) at the antici,ate) official exchange rate at the ti/e of ex,en)iture. For this analsis the financial rate of return an) cash flow is assesse) fro/ the ,ers,ecti-e of autilit owner?o,erator.

The e-aluation /etho)olog follows the tra)itional ,ractice in ,roject analsis where benefitsan) cost strea/s are first esti/ate). For a ,roject to be acce,table ,roject benefits shoul)outweigh costs.

n general ter/s financial e-aluations in-ol-e the following tas(s

1.+2+1 )stimation o7 Pro&e%t Costs

Cost co/,onents inclu)e hea)wor(s an) ,owerhouse construction costs water con-eancecosts )i-ersions an) other ci-il wor(s electro /echanical h)ro /echanical trans/ission an)


Chapter !i(teen

PRO@)CT )V'"'T:ON




sub%station costs ,roject en-iron/ental i/,act /itigation /anage/ent an) /onitoring costs.

7ain access to the ,roject area which is 20 (/ is assu/e) to be borne) b this ,roject. Annualo,erating an) /aintenance ex,en)itures an) re,lace/ent cost for electro%/echanical e>ui,/entare also inclu)e). The costs are allocate) to the ear of ex,en)iture. The financial analsisexten)s the costing to inclu)e taxes an) )uties insurances escalation loan ,rocessing feesinterest )uring construction ca,ital re,a/ent an) interest on )ebt. The /ajor ,ortions of the

,roject cost are )isburse) within the construction ,erio). 4owe-er annual cost inclu)ingo,eration an) /aintenance cost is s,rea) o-er the analsis )uration.

1.+2+2 )stimation o7 Pro&e%t ene7its

For the esti/ation of saleable energ generate) fro/ the ,roject trans/ission loss self consu/,tion an) outages Bsche)ule) an) unsche)ule) are )e)ucte) fro/ the annual generation.For the financial analsis the ,rinci,le ,roject benefits are re-enues which can be )eri-e) fro/the o,eration of the ,roject. A-erage energ rate is esti/ate) ensuring 20O return on e>uit."eturn on e>uit sought b the in-estor is generall O higher than the ,re-ailing interest rateon )ebt. The ,roject benefits are recei-e) )uring the o,eration ,erio) onl.

1.+2+ 8e%ision Ma/in# Tools

n the analsis ,roject costs an) benefits are co/,are) using )iscounte) /easure) of ,roject

worth. Discounting is the techni>ue use) to con-ert a strea/ of benefits or costs to its Present5alue to account for the ti/e -alue of /one. Following are the )ecision /a(ing ,ara/etersesti/ate) )uring this analsis

• '*era#e )ner#y Rate is the (e ,ara/eter use) for /a(ing )ecision. This rate isesti/ate) assu/ing that the Return on )Guity of the ,roject is at the acce,table le-el of the )e-elo,er so that the in-estor are encourage) to in-est in the ,roject. Further thea-erage energ rate shoul) be co/,atible with the ,re-ailing energ tariff.

• The Finan%ial :nternal Rate o7 Return <F:RR= is the )iscount rate corres,on)s to the

9ero !et Present 5alue. That is the )iscounte) rate at which the ,resent -alue of the benefits e>uals the ,resent -alue of costs. The F"" in)icates the financial ,rofitabilitof the in-est/ent ,roject. The F"" is use) to assess whether a ,roject /eets a /ini/u/threshol) or not. f the F"" is less than the )iscount rate which has been use) the

,roject is thought to be unecono/ical as the )iscounte) benefits )o not outweigh the)iscounte) costs. Projects are attracti-e if the calculate) F"" excee)s the cut%off%rate or o,,ortunit cost of ca,ital.

• The ene7it Cost Ratio <;C= is the ratio of the ,resent -alue of the benefit strea/ tothe ,resent -alue of the cost strea/. The '?C "atio in)icates the extent to which the)iscounte) strea/ of benefits excee)s the )iscounte) strea/ of costs. A ratio greater than

one in)icates that benefits excee) costs while a ratio that is less than one in)icates thatcosts excee) benefits.





• 8et !er*i%e Ratio is the ,ara/eter which )e/onstrates the re,a/ent ca,abilit of the ,roject. Financial soun)ness of a ,roject coul) be e-aluate) fro/ this ,ara/eter.

• &enerall )ebt ser-ice ratio of 1. is )esire). 4owe-er for the h)ro,ower ,rojectswhere the /ar(et is guarantee) for its entire econo/ic life through ,ower ,urchaseagree/ent )ebt ser-ice ratio of 1.* shoul) be acce,table.

• Paya%/ Period is the )uration in ear within which entire in-est/ent on the ,roject isreco-ere). Shorter the ,abac( ,erio) better is the ,roject. This ,ara/eter is -eri/,ortant in the countr where the long ter/ go-ern/ent ,olic is not stable.

'ase) on the abo-e financial ,ara/eters in-est/ent )ecision is /a)e b the )e-elo,er as wellas b the financing institutions.

1.+ 'ssumptions

Financial analsis of the ,roject is carrie) out to assess the financial -iabilit of the ,roject. nthis stu) the ,roject is assu/e) to be )e-elo,e) b in-esting its e>uit an) arranging loan fro/co//ercial ban(s.

Following are the basic assu/,tions /a)e for financial analsis

• base ear for the cost an) benefit is 3anuar 2012.

• ntire cost is assu/e) to be local co/,onent. 4owe-er the cost corres,on)ing to ,owerhouse an) generating e>ui,/ents are foreign co/,onent ex,resse) in ter/s of local currenc for this analsis.

• construction ,erio) is ears exclu)ing )etail engineering. The construction wor( in thefirst two ears is li/ite) to the access roa) an) ca/, construction.

• co//ercial o,eration )ate is assigne) to be 3anuar 1 201<.

• escalation rate on the local co/,onent of the cost is assu/e) to be O.

• custo/ of 1O an) local tax of 1.O are assu/e) to be a,,licable on h)ro /echanicalelectrical an) generating e>ui,/ents as these will be i/,orte) fro/ thir) countr usingforeign currenc. Custo/ an) local taxes are not consi)ere) on re/aining ite/s of the

,roject.

• -alue a))e) tax B5AT of 1*O is consi)ere) on entire ,roject cost exce,t on the h)ro/echanical electrical trans/ission line generating e>ui,/ents resettle/ent Ien-iron/ent an) ownerHs cost.

• interest on loan is assu/e) to be 12.0O ,er annu/ an) the interest will be re,ai) ine>ual install/ents an) >uarterl.





• interest )uring construction is ca,itali9e).

• )ebt e>uit ratio is :0*0 for the in-est/ent.

• x,ecte) return on e>uit is 1; O

• stablish/ent fee is assu/e) to be 0.0O of the total loan ,ai) )uring the signing of theloan contract.

• loan )uration is 10 ears after the ear of co//ercial o,eration.

• financial analsis )uration is assu/e) to be *0 ears after the co//ercial o,eration.

• Straight line /etho) with annual )e,reciation rate of +O ,er annu/ is a)o,te).

• annual o,eration an) /aintenance cost is assu/e) to be 1.0O of the total constructioncost an) is escalate) at the rate of O.

• annual insurance cost is 0.O of the construction cost I the total re-enue of three/onths

• insurance cost on the construction cost is escalate) at the rate of O ,er annu/.

• 5AT at the rate of 1*O is a,,licable on the insurance ,re/iu/.

• runner re,lace/ent cost is assu/e) to be *0O of the electro/echanical cost an) isassu/e) to be re,lace) once in ten ears. As of 3anuar 2012 ,rice le-el this cost woul)

be "s. +0+.+* 7illion.

• bonus an) welfare fun) of 2O of net ,rofit annuall.

• roalt on installe) ca,acit is "s. 100 ,er (8 ,er annu/ for first 1 ears an) "s. 1000 ,er (8 ,er annu/ then after. roalt on re-enue is 2.0O on total re-enue for first 1ears an) 10O on total re-enue then after.

• cor,orate tax rate is 20O through out the o,eration ,erio).

• the entire energ is assu/e) to be ,urchase) b !e,al lectricit Authorit through ,ower ,urchase agree/ent in a ta(e or ,a basis for entire ,roject life.

• Sche)ule) an) unsche)ule) outage is assu/e) to be :.O for the esti/ation of thesalable energ.





Disburse/ent of the ca,ital cost is base) on the ,ro,ose) construction sche)ule. For each of theite/s 20O a)-ance is assu/e) to be release) in the first ear i//e)iatel after sigining thecontract for construction. Assu/e) )isburse/ent of the ca,ital cost is ,resente) in Table 1%+<.

1.+5 Result o7 the 'nalysis

Total financial cost of the ,roject inclu)e ,rice escalation taxes an) )uties loan ,rocessing feean) interest )uring construction on )ebt ,ortion of the cost. 'ase) on the assu/e) )isburse/ent

of the cash flow the total financial cost of the ,roject is esti/ate) to be "s. ;0.;+ 7illion.The su//ar of the total financial cost is shown in Table !o. 1 1. #ut of this total cost thee>uit ,ortion is esti/ate) to be "s. 2+1:.0 7illion an) )ebt is "s. *<.:< 7illion. Detail

)isburse/ent of )ifferent costs )uring construction ,erio) is shown in Table !o. 1%2.

Tale 1.?0 !ummary o7 Total Finan%ial Cost 7or "pper Rahu#hatRahu#hat $)P

!+ No+ :temsTotal Cost in

<Million Rs+=1. 'ase Cost as of 6ear 2012 +:0;.2. Phsical Contingenc *<;.01*. Total Cost as of 6ear 2012 10.+. Taxes an) Duties +1;.;

. Total Financial Cost as of 6ear 2012 2.1. Price Contingenc 1+0+.::. Loan Processing Fee 2;.20;. nterest During Construction 10<;.*:-+ Total Finan%ial Cost at the )nd o7 Constru%tion 6,0?.+65

Tale 1.?1 8isursement o7 )Guity and 8et 7or "pper Rahu#hat $)P

Aear Pro&e%t Cost <Million Rs=

)Guity 8et Total

201* :.+2 <.1 1:0.;

201+ +*.*; <;.;+ 1+2.22201 10:.2+ 2*<.*; *+.2201 ;:.;2 1;1.<2 2<2.:+201: ;<.*: 1<.22 2*+;.<201; 2.;2 1:*0.2: 2*.0<Total 2,514+0? ?,.-+4- 6,0?.+65

Long ter/ loan will be ,ai) in 10 ears. nterest as well as loan will be ,ai) in >uarterl basis. tis esti/ate) that e>ual >uarterl install/ent will be "s. 2+*.<< 7illion will be re>uire) to be

,ai) for 10 ears. This is e>ual to the e>ual annual install/ent of "s. <:.< 7illion.

The analsis is carrie) out assu/ing the entire energ will be sol) at the flat rate throughout theear. The rate corres,on)s to the base ear 2012 an) is escalate) at the rate of *O ,er annu/ for nine ears. Accor)ing to the analsis the re>uire) energ rate to ensure 1;O return on e>uit is





"s. .*; ,er (8h B,rice le-el of the 6ear 2012. This rate corres,on)s to "s. .1 ,er (8h for co//ercial o,eriation )ate B6ear 201< an) will be fro9en at "s. .;* ,er (8h fro/ the ear 2020 on war). The F"" of the ,roject is esti/ate) to be 1*.+; O. The corres,on)ing )ebt

ser-ice ratio in the first ear of co//ercial o,eration is 1.1. The benefit cost ratio is 1.*+.Pabac( ,erio) after the co//ercial o,eration for the total in-est/ent is esti/ate) to be ;.*2ears. Detail of the analsis is shown in Table !o.1%*.

Sensiti-it analsis is carrie) out for abo-e scenarios assu/ing the following





Tale 1.?2 Finan%ial 'nalysis with Respe%t to )Guity :n*estement













Case % A Project cost is increase) b 10OCase % ' 'enefit is Decrease) b 10O

Case E C ntire nerg is Sol) at Poste) Seasonal nerg "ates

Details of sensiti-it analsis are ,resente) in the Table !o. 1.* BA 1.* B' I 1.* BC an) inAnnex . The su//ar of the result is ,resente) in the Table 1%+ below

Tale 1.? !ummary o7 the ReGuired '*era#e Tari77 7or 8i77erent Cases

!+ No+ Cases

's o7 2012

<Rs+;/9h=

's o7 201-

<Rs+;/9h=

's o7 2021

<Rs+;/9h=

1+ ase Case .*; .1 .;*

2+ Case H ' 3 Pro&e%t %ost :nreased y10D .<1 :.1 :.1+ Case H 3 ene7it is 8e%reased y

10D

.<: :.22 :.;

5+ Case H C 3 )ntire )ner#y !old at

Posted !easonal )ner#y Rates

;.+0 ? +.;0BDr ? 8et

1.+? 8is%ussion o7 the Result

Fro/ the su//ar of the sensiti-it analsis ,resente) in the Table !o. 1%* it is e-i)ent thatthe total financial cost of the $,,er "ahughat 4P ,roject inclu)ing ,rice escalation taxes an)

)uties loan ,rocessing fee an) interest )uring construction is "s. ;0.;+ 7illion. This gi-esthe a-erage installation cost BFinancial of "s. 10<< ,er (8. The a-erage energ rate of the

,roject woul) be "s. .*; ,er (8h to ensure 1;O return on e>uit. f the ,roject cost isincrease) b 10O the re>uire) a-erage energ rate woul) be "s. .<1 ,er (8h. Decrease ingeneration b 10O woul) result in increase in a-erage energ rate to "s. .<: ,er (8h. Theseenerg rates corres,on) to the base ear 2012 an) will be escalate) at the rate of *O ,er annu/for nine ears. 4igher -alue of energ rate is the result of the higher cost of ca,ital as well as thehigher ex,ecte) return on the in-est/ent because of the higher o,,ortunit cost. The F"" of the ,roject is in the range of 1*.+O. The )ebt ser-ice ratio for the first ear of o,eration is in therange of 1.. This woul) insure ti/el ,a/ent of interest as well as )ebt of the in-estors. The'?C ratio of the ,roject at 10O )iscount rate is in the range of 1.2. This figure shoul) be able toattract the ,ros,ecti-e in-estor. Further the ,abac( ,erio) of the ,roject is in the range of ;.*ears. f the energ is assu/e) to be sol) at the ,oste) rates which are "s. ;.+0 ,er (8h for )r seasonan) "s. +.;0 ,er (8h for wet season the return on e>uit is esti/ate) to be 1+.;;O. Theseenerg rates corres,on) to the base ear of 201< which is the co//ercial o,eration )ate. Thecorres,on)ing )ebt ser-ice ratio for the first ear of o,eration is 1.2< where as the benefit costratio at 10O )iscount rate is 1.1. The F"" of the ,roject is 12.11O an) ,abac( ,erio) is10.1* ears.




Upper Rahughat Hydroelectric Project *ene+ts Fro$ Clean!e"elop$ent #echanis$

14+0 )N)F:T! FROM C)'N 8)V)OPM)NT M)C$'N:!M

14+1 a%/#round

The Clean De-elo,/ent 7echanis/ BCD7 is one of the QflexibilitQ /echanis/s )efine) inthe =oto Protocol . t is )efine) in Article 12 of the Protocol an) is inten)e) to /eet twoobjecti-es B1 to assist ,arties not inclu)e) in Annex in achie-ing sustainable )e-elo,/ent an)in contributing to the ulti/ate objecti-e of the $nite) !ations Fra/ewor( Con-ention onCli/ate Change B$!FCCC which is to ,re-ent )angerous cli/ate changeY an) B2 to assist

,arties inclu)e) in Annex in achie-ing co/,liance with their >uantifie) e/ission li/itationan) re)uction co//it/ents Bgreenhouse gas B&4& e/ission ca,s. QAnnex Q ,arties are thosecountries that are liste) in Annex of the treat an) are the in)ustriali9e) countries. !on%Annex ,arties are )e-elo,ing countries. #bjecti-e B2 is achie-e) b allowing the Annex countries to/eet ,art of their ca,s using QCertifie) /ission "e)uctionsQ fro/ CD7 e/ission re)uction

,rojects in )e-elo,ing countries. This is subject to o-ersight to ensure that these e/issionre)uctions are real an) Qa))itional.Q The CD7 is su,er-ise) b the CD7 xecuti-e 'oar)BCD7 ' an) is un)er the gui)ance of the Conference of the Parties BC#P?7#P of the $nite)

!ations Fra/ewor( Con-ention on Cli/ate Change B$!FCCC.

The ,ur,ose of the CD7 is to ,ro/ote clean )e-elo,/ent in )e-elo,ing countries i.e. theQnon%Annex Q countries Bcountries that arent liste) in Annex of the Fra/ewor( Con-ention.The CD7 is one of the Protocols Q,roject%base)Q /echanis/sY in that the CD7 is )esigne) to

,ro/ote ,rojects that re)uce e/issions. The CD7 is base) on the i)ea of e/ission re)uctionQ,ro)uctionQ. These re)uctions are Q,ro)uce)Q an) then subtracte) against a h,otheticalQbaselineQ of e/issions. The e/issions baselines are the e/issions that are ,re)icte) to occur in

the absence of a ,articular CD7 ,roject. CD7 ,rojects are Qcre)ite)Q against this baseline inthe sense that )e-elo,ing countries gain cre)it for ,ro)ucing these e/ission cuts.

The econo/ic basis for inclu)ing )e-elo,ing countries in efforts to re)uce e/issions is thate/ission cuts are thought to be less ex,ensi-e in )e-elo,ing countries than )e-elo,e) countries.For exa/,le in )e-elo,ing countries en-iron/ental regulation is generall wea(er than it is in)e-elo,e) countries. Thus it is wi)el thought that there is greater ,otential for )e-elo,ingcountries to re)uce their e/issions than )e-elo,e) countries.

The A)a,tation Fun) was establishe) to finance concrete a)a,tation ,rojects an) ,rogra//es in)e-elo,ing countries that are Parties to the =oto Protocol. The Fun) is to be finance) with ashare of ,rocee)s fro/ clean )e-elo,/ent /echanis/ BCD7 ,roject acti-ities an) recei-efun)s fro/ other sources.


Chapter !e*enteen

)N)F:T! FROM C)'N 8)V)OPM)NT

M)C$'N:!M

http://en.wikipedia.org/wiki/Flexibility_mechanisms

http://en.wikipedia.org/wiki/Kyoto_Protocol


http://en.wikipedia.org/wiki/Sustainable_development


http://en.wikipedia.org/wiki/United_Nations_Framework_Convention_on_Climate_Change



http://en.wikipedia.org/wiki/Climate_change

http://en.wikipedia.org/wiki/Greenhouse_gas

http://en.wikipedia.org/wiki/Certified_Emission_Reduction

http://en.wikipedia.org/wiki/Flexibility_mechanisms





http://en.wikipedia.org/wiki/Climate_change

http://en.wikipedia.org/wiki/Greenhouse_gas

http://en.wikipedia.org/wiki/Certified_Emission_Reduction




14+2 ene7it 7rom C8M to "pper Rahu#hat $ydro )le%tri% Pro&e%t

Currentl !A is facing a )ail energ shortage of 00 78h an) a ,ower shortage of 2078. 8estern astern an) Central regions ha-e ,ower shortages of * 78 78 an) +2078 res,ecti-el. As a result the countr is going through a loa) she))ing of 1+ hours. -enthough the )eclare) loa) she))ing hours in the central region is 1+ hours !A has been force)to resort to unsche)ule) ,ower cuts to /anage the )e/an). #ut of the total installe) ca,acit of ;: 78 onl *0; 78 was a-ailable )uring the winter of 200<%10. -en with a /axi/u/a-ailable i/,ort ca,acit of ;0 78 a )eficit of o-er 0O of )e/an) was ine-itable.

The ,ea( energ )e/an) is growing at an a-erage annual rate of about 10O.Thus each ear the

)e/an) increases b 100 78. Shortage of energ an) ca,acit is ex,ecte) to continue for >uiteso/e ti/e to co/e as there is no significant a))ition of generating ,lants. The shortage hasforce) !A to resort to loa) she))ing. The ,rojection of )e/an) an) su,,l for the next earsis as gi-en below

Tale 14?5 )ner#y 8emand Pro&e%tion "p to 2041;42

Fis%al Aear

)ner#y <M9h= oad

!heddin#

<hrs=8emand '*ailale !urplus

20:?;

8et Season 12;1* 122 %2;; 2

Dr 7axi/u/ 1+*< ;+: %<02 1+

20;?<8et Season 1*<02 1*000 %<02 *Dr 7axi/u/ 1<0 ;+: %<+* 20

20<?:08et Season 1+;: 1*1*0 %1:+ Dr 7axi/u/ 1;2 ;+: %;0* 20

20:0?:18et Season 1<1 1+<*0 %<; Dr 7axi/u/ 1:;+< <;+: %;002 20

20:1?:28et Season 1:0*1 2+;;2 :;1 0Dr 7axi/u/ 1<0<< 12;1 %2+; 1+

Tale 14?? Power 8emand Pro&e%tion "p to 2041;42

Fis%al AearPower <M9=

8emand '*ailale !urplus

20:?;8et Season ;:1 00 %2:1Dr 7axi/u/ <0 0 %+++

20;?<8et Season <+0 ;2 %2;Dr 7axi/u/ 102 22 %0+

20<?:08et Season 101 :*; %2:;Dr 7axi/u/ 110; 22 %;

20:0?:18et Season 10<: ;*0 %2:Dr 7axi/u/ 11<: ; %*<Dr !or/al 11:2 2* %+<

20:1?:2 8et Season 11; 12; 101





Dr 7axi/u/ 12<2 ;** %+<

At ,resent !e,al is un)ergoing a huge ,ower shortage e>ui-alent to al/ost 1+ hours )uring the)r season an) about + hours )uring the wet season. This situation will (ee, on increasing to 22hours )uring the )r season an) about 10 to 12 hours )uring the wet season ,rior to theco//issioning of new h)ro,ower ,rojects li(e $,,er Ta/a(oshi so/eti/e in 201;?1<.

-en after the co//issioning of $,,er Ta/a(oshi 4)roelectric Project the countr will facethe sa/e loa) she))ing situation as it is facing at the ,resent )ue to the constant increase in the)e/an). n other wor)s there will be a huge i/,ort of ,etrol an) )iesel fuel fro/ n)ia for thegeneration of electricit b /eans of using generators ha-ing s/all as well as large ca,acities.As ,er the i/,le/entation sche)ule of $,,er "ahugaht 4P it can start generating ,ower fro/the ear 201< onwar)s. ' this ti/e the )eficit of ,ower will ha-e grown /uch /ore than the

installe) ca,acit of this ,roject which is +< 78. Co//issioning of this ,roject b the ear 201< will re,lace the re>uire) generation of an e>ui-alent ca,acit of ,ower fro/ )iesel ,lants.This can be consi)ere) as a benefit to the countr in ter/s of a-oi)ing the nee) to i/,ort fuelfro/ a thir) countr. !e,al being a signator countr of =oto Protocol can be inclu)e) in the

benefits an) $,,er "ahugaht 4P can be an eligible can)i)ate for CD7 benefit.

The benefit strea/ for the ,roject is base) on the sale of ,ower an) >uantification of the benefit b re)ucing e/issions fro/ an e>ui-alent ther/al generation alternati-e. This ,roject locate) inthe 8estern De-elo,/ent "egion shall )irectl re)uce the nee) to o,erate gas%turbine /ulti%fuel)iesel ,lant locate) in this region. This re)uction will be e>ui-alent to the actual generation fro/

$,,er "ahughat 4)ro,ower Project. The assess/ent of the e/ission benefits Bcre)it is ,resente) below





Tale 14?. Parameters 7or the )*aluation o7 the )mission Credit

8es%ription )mission

<#;/9h=

rate, )(ternal Cost

<"!8;ton=

)(ternal Cost

<"!%;/9h=

C#2 &as Turbine :0 10 0.:S#2 &as Turbine * +00 0.12

!#x &as Turbine 1 20 0.02C#2 7ulti Fuel Diesel 00 10 0.S#2 7ulti Fuel Diesel *. +00 0.1+

!#x 7ulti Fuel Diesel 0.* 20 0.00:

WSource !A Sste/ Planning De,art/ent 7i))le 7arsang)i Project -aluation "e,ort.

Tale 14?4 Parameters 7or the )*aluation o7 the )mission Credit

8es%riptio

n

)(ternal

Cost

<"!%;/9h

=

Redu%ed

/9h <8ry

!eason=

Redu%ed

/9h <9et

!eason8ry

!eason=

)mission

Credit

<"!8=

7rom 8ry

!eason

)ner#y

)mission

Credit

<"!8= 7rom

9et !eason

)ner#y

C#2 7ulti FuelDiesel 0.

+1;00000.00

2+210000.00

20;00.00

1+0.00

S#2 7ultiFuel Diesel 0.1+

+1;00000.00

2+210000.00 ;20.00 **<+.00

!#x 7ulti FuelDiesel 0.00:

+1;00000.00

2+210000.00 *1*.00 1;1<.:

Total /ission Cre)it in

$SD

*12+.0

0

1;1*0<.:

Tale 14?6 ene7it )*aluation 7rom a#ar Khola Power Plant

8es%ription )(ternal

Cost<"!%;/9h=

Redu%ed

/9h <8ry

!eason=

Redu%ed

/9h <9et

!eason 8ry

!eason=

)mission

Credit

<"!8= 7rom

8ry !eason

)ner#y

)mission

Credit

<"!8= 7rom

9et !eason

)ner#y

C#2 7ultiFuel Diesel 0. **0000.00 1:10000.00 1<;0.00 1020.00

S#2 7ultiFuel Diesel 0.1+ **0000.00 1:10000.00 +2.00 2*<+.00

!#x 7ulti 0.00: **0000.00 1:10000.00 2+.: 12;.2





Fuel DieselTotal /ission Cre)it in$SD

2+.: 12:;2.2

The e/ission cre)it has been esti/ate) se,aratel for the )r season Bfour /onths fro/ /i)Dece/ber to /i) A,ril an) the wet season for energ generation fro/ $,,er "ahughat4)roelectric Project an) the ,ower ,lant at 'agar =hola an) is shown in Table 1:.+ an) 1:..n the ,resent context !e,al cannot a-oi) the re>uire/ent to fulfill its )r season energ)e/an) which will /ost ,robabl be /et b the o,eration of /ulti%fuel ,lant. !A can thusclai/ a))itional e/ission cre)it e-en )uring the wet%season b selling energ to n)ia if a))itional ,ower ,lants in this region will be a))e) to the !PS sste/.

The e/ission cre)it has not been consi)ere) in the financial e-aluation of the ,roject. 'esi)eswhile negotiating for the PPA !A /a negotiate the energ rates acce,table to the )e-elo,er an) ta(e the benefits of the e/ission cre)it to his organi9ation.








Upper Rahughat Hydroelectric Project Conclusions andReco$$endations

16+0 CONC"!:ON! 'N8 R)COMM)N8'T:ON!

The ,ower sste/ of !e,al has grown to a /uch bigger ca,acit now an) is still continuing togrow. The ,ercentage share of ,ri-ate ,ower generation in the ,ower sste/ has beenincreasing. Polic of !e,al lectricit Authorit to encourage the ,ri-ate ,ower ,ro)ucer b

,urchasing energ through the Power Purchase Agree/ent has ,ro-e) to be a new /ilestone inthe )e-elo,/ent of h)ro,ower in !e,al.

Tun)i Power Co/,an an in)e,en)ent ,ower ,ro)ucer BPP is ,lanning to i/,le/ent $,,er "ahughat 4)roeletric Project an) for this ,ur,ose the PP has obtaine) the license to carr outthe sur-e an) the feasibilit stu) of this ,roject. The T#" for the stu) of the ,roject hasalrea) been a,,ro-e) b the concerne) authorit. The PP entruste) A,ex nerg P-t. Lt) toloo( into the technical an) financial -iabilit of the ,roject an) to ,re,are the o-erall feasibilitstu) re,ort for the ,roject.

$,,er "ahughat 4)roelectric Project is locate) in Pa(ha,ani 5DC Chi/(ola 5DC an)Dagna/ Dar/ija 5DC of 7ag)i District in 8estern !e,al. The site is locate) about **+ (/northwest of =ath/an)u an) about ;* (/ west of Po(hara.

Due to the -irtue of the location of this ,roject $,,er "ahughat 4)roelectric Project can be)e-elo,e) in two was one as an in)e,en)ent ,ower ,roject with an in)e,en)ent hea)wor(salong the "ahughat "i-er an) the secon) as a casca)e ,roject of "ahughat E 7angale4)ro,ower Project.

f "ahughat 7angale was to be )e-elo,e) as an in)e,en)ent ,roject a se,arate hea)wor(s witha )esan)er woul) ha-e to be built across "ahughat so/ewhere )ownstrea/ of the confluence of "ahughat an) 'agar =hola. Since there is a ,ossibilit of using the )ischarge fro/ the tailraceof "ahughat 7angale 4P buil)ing a se,arate hea)wor(s woul) result in unnecessar extracosts. Further/ore o,ting for the first wa of )e-elo,/ent woul) result in the loss of hea) thatexists between the ,ro,ose) ,owerhouse of "ahughat 7angale an) the su,,ose) location of thehea)wor(s of $,,er "ahughat 4P if it were built.

Alternati-el the secon) wa to )e-elo, the ,roject woul) be to )i-ert the tail water of "ahughat 7angale 4)ro,ower Project into the hea)race tunnel of $,,er "ahughat

4)roelectric Project b constructing an interconnection sste/ at the ,owerhouse of "ahughat7angale 4)ro,ower Project at 'agar =hola. This sche/e will not nee) the construction of ase,arate hea)wor(s an) )esan)ing basin. 4owe-er in or)er to collect the )ischarge fro/ 'agar =hola a s/all )i-ersion weir an inta(e an) a )esan)er will be nee)e) along 'agar =hola


Chapter )i#hteen

CONC"!:ON! 'N8 R)COMM)N8'T:ON!




u,strea/ fro/ the location for the ,owerhouse of "ahughat 7angale 4P ,roject. The)ischarge fro/ 'agar =hola will be a))e) to the )ischarge fro/ "ahughat 7angale 4P in thecollection cha/ber an) then con-ee) to the hea)race tunnel of $,,er "ahughat 4P.

t is >uite ob-ious fro/ the abo-e argu/ents that the secon) alternati-e is /uch /ore attracti-ein ter/s of cost as well as benefits. Since )e-elo,ing this ,roject as a casca)e sche/e will ha-ehigher financial benefits this feasibilit stu) for $,,er "ahughat 4P has been un)erta(en asa casca)e )e-elo,/ent of "ahughat E 7angale 4)ro,ower Project with the inclusion of theannual flows fro/ 'agar =hola.

The choice for the secon) alternati-e is further strengthene) b the )ecision to utili9e the flowfro/ 'agar =hola for the ,ro)uction of ,ower locall as well as ,ro)uction of ,ower b a))ing

it to the )esign flow of $,,er "ahughat 4P.

The ,roject will thus consist of a hea)wor(s structure locate) at the confluence of "ahughat=hola an) 'agar =hola.The ,ro,ose) hea)wor(s structure basicall consists of structuresinterconnecting the tailrace of "ahughat 7angale 4)ro,ower Project B"74P a ri-er )i-ersion structure a )esan)er an) a s/all ,owerhouse for generation of ,ower at 'agar =holaan) the inta(e for $,,er "ahughat 4)roelectric Project B$"4P. The tailwater fro/ "74Pis ,ro,ose) to be brought across 'agar =hola to its left ban( si)e with the ,ro-ision of a cut an)co-er box cul-ert structure. The )ischarge fro/ 'agar =hola will also be )i-erte) with the

,ro-ision of a s/all weir across the (hola as well as a )esan)er an) a ,owerhouse for ,ower

generation before being )i-erte) into a collection cha/ber locate) just u,strea/ fro/ the inta(e ,ortal for the hea)race tunnel of $"4P. The cut an) co-er box cul-ert carring the )ischargefro/ the tailwater of "74P will also be connecte) to this collection cha/ber so that the flowsfro/ both "74P an) 'agar =hola tailrace can collecti-el be release) into the inta(e ,ortal of the hea)race tunnel for $"4P.

The flow fro/ the collection cha/ber will be con-ee) to the surgetan( -ia a low ,ressurehea)race tunnel. The surge tan( will be connecte) to the surface ,owerhouse b /eans of aco/bination of a surface ,enstoc( an incline) )ro,shaft an) a high ,ressure tunnel. The

,owerhouse will be locate) on the left ban( of "ahughat =hola.

$,,er "ahughat 4)roelectric Project )oes not ha-e a /otorable access roa) at ,resent. Thenearest roa)hea) to this ,roject is an earthen roa) that starts fro/ &aleshor an) en)s at=ha,sin)a)a -ia 7auwa,hant. A -illage roa) which is fairl wi)e exists at ,resent fro/7awa,hant?=ha,si)an)a u, to Chi/ =hola -illage which is locate) at the confluence of 'agar =hola an) "ahughat =hola an) is also the ,ro,ose) location for the hea)wor(s of this ,roject.The length of this roa) is a,,roxi/atel 20 (/. t is therefore en-isage) that a,,roxi/atel 20(/ of access roa) will be re>uire) for the i/,le/entation of the ,roject while a further ; (/ of

,roject roa)s will be re>uire) to access the )ifferent ,roject sites.

!A is currentl constructing "ahughat 4)roelectric Project the hea)wor(s structure of whichis locate) about :00 / )ownstrea/ of the ,owerhouse site ,ro,ose) for this ,roject. t isen-isage) that the access roa) u, to the hea)wor(s site of "ahughat 4)roelectric Project beingi/,le/ente) b !A will alrea) be in ,lace before the i/,le/entation of this ,roject.





The o,ti/i9ation stu) carrie) out for "ahughat 7angale 4P shows that the o,ti/u/ )esign)ischarge is esti/ate) to be 1*.0 /*?s. The )esign flow a-ailable fro/ 'agar =hola is *.2 /*?s.

Since $"4P is a casca)e )e-elo,/ent of "74P the su/ total of these flows e>ui-alent to1.2 /*?s has been consi)ere) for the )e-elo,/ent of the ,roject. For the a-ailable gross hea)of *:; / an) a hea) loss of .+: / the installe) ca,acit of the ,roject co/es out to be +;.078. Si/ilarl for a )esign flow of *.2 /*?s a gross hea) of 1* / an) with a hea)loss of 0.1 /the installe) ca,acit for ,ower generation at 'agar =hola co/es out to be 0.*2 78.

A total annual energ of 2;+.+1 &8h is esti/ate) to be generate) fro/ this ,roject. Assu/ingPoush to Chaitra Ba total of four /onths as the )r season the total )r season energ isesti/ate) to be +1.;0 &8h whereas the total wet season energ is esti/ate) to be 2+2.1 &8h.7ini/u/ ,ower generate) fro/ the ,lant is esti/ate) to 1*.+ 78.

Si/ilarl a total of 2.0+ &8h of annual energ is esti/ate) to be generate) fro/ the ,ower generation facilit at 'agar =hola. #ut of this the total )r season energ is esti/ate) to be 0.**&8h whereas the total wet season energ is esti/ate) to be 1.:1 &8h. 7ini/u/ ,ower generate) fro/ the ,lant is esti/ate) to 0.10 78.

The construction ,erio) of this ,roject can be categori9e) into two )istinct stages. The first stagewill be the construction of the access roa) an) other ,re,arator wor(s while the secon) stagewill consist of the actual construction of the ,roject. The )urations for these stages area,,roxi/atel three ears each. The total )uration for the construction of this ,roject inclu)ingengineering construction of access roa) an) other ,re,arator wor(s is therefore about :2

/onths.

The total esti/ate) cost of the ,roject inclu)ing the ,hsical contingenc is $S N *.;** at the3anuar 2012 ,rice le-el.

The total financial cost of the ,roject inclu)es ,rice escalation taxes an) )uties loan ,rocessingfee an) interest )uring construction on )ebt ,ortion of the cost. 'ase) on the assu/e))isburse/ent of the cash flow the total financial cost of the ,roject is esti/ate) to be "s.;0.;+ 7illion. #ut of the total cost the e>uit ,ortion is esti/ate) to be "s. 2+1:.0 7illionan) )ebt is "s. *<.:< 7illion.

Long ter/ loan will be ,ai) bac( in 10 ears. The interest rate on the )ebt will be 12O. nterestas well as loan will be ,ai) on a >uarterl basis. t is esti/ate) that e>ual >uarterl install/entswill be "s. 22. 7illion an) this will be re>uire) to be ,ai) for 10 ears. This is e>ual to thee>ual annual install/ent of "s. 11:+.<* 7illion.

The financial analsis has been carrie) out assu/ing that the entire energ will be sol) at a flatrate throughout the ear. The rate corres,on)s to the base ear 2012 an) is escalate) at the rateof *O ,er annu/ for nine ears. Accor)ing to the analsis the re>uire) energ rate to ensure a1;O return on e>uit is "s. .*; ,er (8h B,rice le-el of the 6ear 2012. This rate corres,on)sto "s. .1 ,er (8h for co//ercial o,eriation )ate B6ear 201< an) will be fro9en at "s. .;*

,er (8h fro/ the ear 2020 onwar). The F"" of the ,roject is esti/ate) to be 1*.+; O. Thecorres,on)ing )ebt ser-ice ratio in the first ear of co//ercial o,eration is 1.1. The benefitcost ratio is 1.2+. Pabac( ,erio) after the co//ercial o,eration for the total in-est/ent is





esti/ate) to be ;.*2 ears. f the energ is assu/e) to be sol) at the ,oste) rates which are "s.;.+0 ,er (8h for )r season an) "s. +.;0 ,er (8h for wet season the return on e>uit isesti/ate) to be 1+.;;O. The corres,onsing F"" of the ,roject will be 12.11O. The benefit cost

ratio at the 10O )iscount rate woul) be 1.1.

The feasibilit )esign of the ,roject has been carrie) out on the basis of -er li/ite)t h i l i ti ti All ) ti ) i S ti 10 2 ) t b ) i

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Final Report Upper Raghughat

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