PRELIMINARY ENGINEERING REPORTWELK DAM IMPROVEME]VT

swc # 4ooEMMOAI,S COUNTY

NORTH DAKOTASTATE WATER COMMI,S,S/OAI

JULY I99I

iCT LOCATION.ROJ

83

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in-./_-l

PRELIUTNARY ENGINEERING REPORT

WEI¡K DÀI{ Tì{PROVE¡íENTSswc PRoJECT #400

No¡:th Dakota State lûater Commission900 East Boulevard

Bismarck, l{orth Dakota 58505-0850

Prepared by:

IlansonResource Engineer

Subnitted by:

L. Frink, DirectorWater Development Division

by:

À. ,State Eng

r.rr.

III.

PI'RPOSE .AND

BACKGROT'I[D

DESCRTPTION

LocatÍon and

TÀBI,B OF CONTEIITS

scoPE.

aaaa

OF .àREÀ.

Basin Description

Pace

I3

4

10

101010L2L2L2L414L41515161520202323232426313234

3s

36

37

42

444566I

Climate. . . .Geolog-y. .Hydrolog'y.Dam Description. .Dam Design ClassificatÍon.Sedimentation. .

rV. DESCRIPTIOII OF PRO.]ECTDiscussion of ÀlternativesÀIternat,ive One.

Breaching the Embanlsnent.Cost Est,imateAlternativeTwo.. ..Rehabilitating Spillway . .Cost EstimateAlternative Three. . .Construction of a New Spillway.Hydrology . . .Hydraulics.......Preliminary Design. . . . . . .

CI'tp SpillwayCost Estimate - Àlternative 3À.Concrete ChuteCost Estimate - Àlternative 38.Àlternat,iveFour ...Construction of New DamHydrology :Principat Spillway.EmergencySpillway... ..Embankment DesignCost Est,i¡nate

BIIVIRONUENTÀL ÀSSESSIiENT

I,AND RTGHTS.

slnftfÀRY.

RECO}O,IEIIDÀTTON

v.vr.

VII.VIII.

(.

Cost Estimate.

I

42

TÀBI_,8 OF CONTENTS (CO¡IT. )

FIGI'RES

-LocationMap.. ....SÍte Topography . .- Prof ile - 6 feet C¡fP.- Plan View - Two 6 feet CI,IP. . . . .- Profile - Concrete Chute. .- Plan View - Concrete Chute. . . . .- New Dam Location. .25- and 100-year Rainfall Hydrograph0.3 PMP Hydrograph. . . .- Traverse Profile of Dam at Principal- Emergency Spillway Proposed Dam :

Spillway

Paoe

27

18192L222528293033

1516

2626

27

FÍgure 1Figure 2Figure 3FÍgure 4Figure 5Figure 6Figure 7Figure IFigure 9FÍgure 10Figure 11

Table 1Table 2Table 3Table 4Table 5

TÀBLES

- Peak Inflows and volumes for DesignSO-Year Event

- Area-Capacity Curve. . . .- Peak Inflows and Volumes for DesignFrequency 6-hour Rainfall Event-NgwDamSite.... .. ...- Result,s of Hydrology StudyProposed 5 Lf2-foot Diameter RCP.

ÀPPEIIDICES

ÀPPENDIX À - ÀGREEMENTAPPENDTX B - WÀTER QUÀLITY ÀNÀLYSIS

, -J.I-

t

r PT'RPOSE À¡ID SCOPE

In January of 1991, the North Dakota State lvater Commissionentered into an agreement with the Emmons County Water ResourceDistrict to investigate the feasibílity of repairÍng or replacingof I{elk Dam. A copy of the agreement is incruded Ín AppendÍx A.Figure 1 shows the location of I{eIk Dam within the state.

This report contains a history of activÍty related to WelkDamr a description of the study area, hydrologic and hydraulÍcanalysis of the drainage basin, a su¡nmary of the preliminarydesign of the project, a cost estimate based on the preliminarydesÍgn alternativesr ân environment,al assessment, descript,ion ofland rights and finarry, a statement of conclusíons, andreconmendations regarding the project.

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PROPOSED DAM SITE

EXISTIN GDAMSITE

¿

^\\

ONS

LINTot{

EMM

FIG 1 LOCATION MAP-2-

IT. BÀCKGROITITD

WeIk Dam was constructed by the Ilork Progress Àdministrationin the mid-1930s to provide fish habitat and recreation. The damwas fi-rst referred to as Meier Dam, until the name was changed toIüelk Dam in the late 1940s. SÍnce its const,ructÍon, theprincipal spillway has required periodic repair work consistÍngmainly of guniting concrete on the spillway. RepaÍrs andmodifications to the principal spillway occurred in 1945, 1950,1955, and 1958.

In ltarch L975, a meeting was held with the Emmons Countyl[ater llanagement District in discussion of designing a downstreamdam site. The State l{ater Commission presented prelÍminaqf datafor the proposed downstream site. The nerÍ site would have acontrol elevat,Íon of 1840 feet (msl), an 8?-acre pool, and a23-foot, average depth. The prelÍminary data presented was from aquadrangular map of the area. There was discussion on the amountof farm land that needed to be acguired and concluded that atopographic map clearly defining the tracts of land wourd berequired. No further progress was made on the project.

The St,ate I{ater Commission's inspect,ion of I{eIk Dam in 1990,noted the poor condition of the spillway and undermining,cracking and deterioration of the wingwalls. For safety reasons,the Emmons County lfater Resource District has requested aninvestigation on Welk Dam to provide alternatives for repairingor replacing the dam.

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t_

ITI. DESCRTPTIO¡Ü OF ÀREÀ

Locat,ion and Basin Description:!{elk Dam is located in the SEL/4 of Section 33, Township 131

North, Range 77 West,. The site is seven miles west andone-half-mile south of Strasburg, in Emmons County (see Figure1). The embankment lies across Little Beaver Creek approximately11 miles above entry with Oahe Reservoir.

The drainage area above I{elk Dam Ís 16 square miles, TheLittle Beaver Creek valley flattens and widens upstream of thereservoir. The bluffs rise to elevation 2100 mean sea level(msl). !Íost, of the upstrearn drainage area is under cultivationwÍth the exception of the steep slopes of the buttes and theirtops.

Climate:Precipitation for crop production is adequate during normal

years, although occasionally the area suffers from periods ofdrought,. The tot,al annual precipitation is L7 .3 inches . Ofthis, L4 inches or 82 percent usually falls in AprÍI throughSeptember, which includes the growÍng season for most crops. Theaverage temperature is 13 degrees Fahrenheit during the winterand 69 degrees Fahrenheit during the surnmer.

GeologrX':

I{elk Dam, and its drainage area, lie within the MissourÍPlateau in the Great Plains Province. It is on the óoteau slope,

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which is the glaciated section of the Missouri plateau. soilformat,ions are Bearpaw and vebar series which consist of deep,well-drained, srowly permeable soils on gracial tilr plains.Slope ranges from 1 to 50 percent.

Hvdrolomz:

--

À hydrologic analysÍs of the watershed tras performed usingthe HEc-1 computer model, deveroped by the u.s. Ànny corps ofEngineers. It was used to determine the peak discharges and flowvolumes of varÍous frequency storms. rt formurates amathematical hydrotogic model of the watershed based on thefollowing data: The amount of rainfall, the rainfalldistribution, soíl type, land use, and the hydrauliccharacterÍst,ics of channeLs and drainage areas. The HEc-l modelis designed Lo calculate the surface runoff of the watershed, inreration to precipit,ation, by representing the basin as aninterconnected system of hydrologic and hydraulic components.Each component of the nodel represents an aspect of theprecipitation-runoff process within a portion of the subbasÍn.These components were put into the model to determine themagnit'ude and duration of runoff from hydrologic events with arange of frequencÍes.

The model was developed to determine the hydrologic responseof I{eIk Dam watershed. The results gained fro¡n the nodelincrudeds (1) infrow hydrographs, (2) reservoir stagehydrographs, and (3) out,flow hydrographs.

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Dam Description:The lfelk Dam embanlrcnent is a rolled earth-filted type whose

top elevation is 1849 msl. The 24-foot. high embanJ,cnent has a3H:1v (3 horizontar to 1 vert,icar) sropes for both upstream anddownstream faces with riprap on the upstream slope. The top ofthe embankment is 400 feet rong and 20 feet wÍde. À row-leveldrawdown pÍpe is not incruded as part of the structure.

The prÍncipal spirlway consists of an approach channer, ogeeconcrete spillway, and a plunge pool. The approach channelconsist,s of a flat curved earth channel approximately 50 feet,rong at the same elevation as the principar spillway (1939 msr).The princÍpar spirlway is 42 feet wide wÍth a face slope oflH:lV. The st,illing basÍn consists of the original l0-foot long,flat rubble masonry apron and a secondary drop 10 feet long and 3feet, deep. The crest, elevation of the principal spillway Ís lg40msl. The reservoir's water surface is at 1B4o msl, covers 29.!acresr and the capacity is 205 acre-feet. The average depth is7.3 feet and maximum depth is 19.? feet (see Figure 2 siteTopography l{ap).

Dam Desigm Classification:Dams are classified according to their potential hazard to

property and potential for ross of life, íf the dam shourdsuddenly fail. Ifelk Dam is located in a rural area where thereis little probability of future residential developmentdownstream of the dam site. Failure of t,hÍs dam could result in

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EXISTING DÀM

5' CONTOAR INTERUALS

FIG 2SITE TOPOGRAPTIY-7-

INORMAL POOL ELEVATTON IA4OTOP OF DAM ELEUATION

'A49LOTEST ELEUATION I A2 '.9

VOLAME(a,cl"'e feeC)6a195205s79

604

AREA(o.orec)22II4

gat6

2A4t.60-,

ELEV.(tnsL),a26tago,aa6,440ta46,450

AREA CAPACITY TAELE

damage to agriculturar land and townshÍp roads, however, no lossof life would be expected. Therefore, I{eIk Dam is considered a.lor hazard dam. The embankment heÍght, is 24 feet, classifyingI{elk Dam as classification IT, according to the North Dakota DamDesign Handbook.

Sedinentation:The rate of sedÍmentation in reservoirs is dependent upon

the amount, of soil eroded from the watershed and transported intothe reservoÍr. There are several factors which determine theamount, of sediment that is carried by surface runoff. Àmong themare soil type amount, of runoff, slope of land, land use, andconservation pract,ices used. ÀIso contributing to the sedimentaccumulation is the organíc material that, is generated withÍn thereservoÍr itself.

SedimentatÍon in the Ìlelk Dam could be reduced by examinÍngthe watershed to determine land treatment measures which couldreduce the erosion rate. Treatment pracÈices includeconservation croppÍng systems, crop residue use, stubblemulching, strip cropping, contour plowing, grassed waterways,windbreaks and buffers, and sediment catching ponds.

There is limited data available on the total sedimentaccumulation in the reservoir. An original topographic map ofthe reservoir area is not available and no sedimentation surveysof the reservoir have been completed. Comparing the elevations

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ù

uPst,ream and downst,ream of the dam, sedimentation has occurredand is estímated at 2 feet, deep.

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IV. DESCRIPTION OF PROJECT

Discussion of Àlterrrat,ives :Àct,ion must be taken to prevent Welk Dam from failing due to

a high runoff event. The existing spillway is Ín poor condit,ion.The spillway has incurred extensive undermining wÍth cracking anddeterioration of the wingwalls.

There are four alternatives considered that, will eit,herÍmprove the existing spillway or construct a nen dam downstrea¡n.The first, alternat,ive consists of breaching the existÍngembankment, and drainíng the reservoir. The second alternativeconsists of restoring the existing spillway. The thirdalternat,ive is replacing the spÍllway with a new outletstructure. The outlet, structures to be considered are corrugatedmetll pipes and a concrete chute. À nen dam constructeddownstream will be the fourth alternat,ive.

ÀIternative OneBreaching the Embanlment,:

The first, alternative is breaching the embankment anddraining the reservoir. This could be done immediately,preferably in the fall before the next spring runoff. Dependingon the level of the reservoir, Ít may be necessary to síphon orpump the level of the reservoir down a few feet prior tobreaching the embankment. Lowering the reservoir level prior tobreaching the embankment would reduce the risk of damagingdownstream areas.

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Àn option to draÍn the reservoÍr would be to excavate anotch in the do¡vnstream half of the embankment, Ínstall a gatedcurvert, backfilr around the culvert, and excavate the upst,reamside of the embankment allowing the reservoir to drain throught,he culvert at an orderly rate. The controlled releases throughthe culvert would help prevent downstream erosion and decreasethe sediment, load of the rereased flows. Breaching theembankment. would provide less control over the releases and couldresult in downstream flooding, erosion, and sedimentatÍonproblems.

À channel, with a maxÍmum depth of approximately 4 feet,would be required upstream and downstream of the embanl

circumstances. The breached area would be available as a site fora new spillway which might be built, at some later date. The cost,sunmary for breaching and draining Welk Dam is provided in Table1. The tot,al cost for this alternative is $181000.

Cost, Estimate - Àlterrrative OneTtam IIni t llot-aI

Ìlobilization LSTravel LSCoffer Dam LSDemolish Structure LSExcavate Notch LSDrain Lake LSI{iden and Stabilize Notch LSSeeding and Cleanup LS

SubtotalEngineering 10tÀdministration 10tContÍngenciesTotaI

$ 1r500.001r500.001,500.003,500 . 003,000.001,000.001, 000 . 00

500.00$13,500.00

1, 350 . 00I,350.00]- 800.00

$18,000.00

ÀIternatiwe TnoRehabilitatíng Spillwav:

The second alternative would consist ofspillway through the use of g,trnite. There hasundermÍning to the spillway creating large voidsconcrete. Gunite would be pumped into the voidsand st,abilize the spillway.

restoring thebeen excessiveunderneath theto add support

An inspection of the spillway was performed by boring holesÍnto the concrete floor. The borings consisted of 2-inch holesdrilled at random throughout the face of the spillway. Thedepths of the voids were measured in each hole and recorded. The

o

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¿t

Ìargest voÍd found was 27 inches below the 12-ínch concrete slab.This void was located on the west, side of the weÍr watlapproximately halfway down. Borings on the bottom of thespillway face revealed void depths of L7 inches and 9 inchesbelow the concrete slab. The voids were rocated on the west,harf, there ïrere no voids discovered on the east harf of theweir. The thickness of the concrete slab varied from L2 to 16inches thick throughout the face of the spillway.

Holes were drilled on the crest of the spillway, but novoÍds were found. Therefore, it does not, appear that the seepageis entering directly in front of the spitlway. since the voidsrùere only found on the west harf of the weir, it has beenconcluded that the water is entering from under the westwingwall

Several holes Ìtere drilled randomly across the first 8-incht,hick concrete apron. The depths of the voids below the concreteapron ranged from 10 to 13 inches. The second apron was L2Ínches thick with voids ranging from 5 to 10 inches. Thesecondary drop Just below the toe of the dam had l8-inch holesbored which revealed a voÍd with a 6-inch depth, with waterfilling the void.

The amount of gunite needed to fill the voids is estimatedat 75 cubic yards. The total cost estimate for rehabititation is$25r000. Rehabirítation wourd not include wingwall repair.

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RehabÍlitation of the wingrvalls would be difficult because oftheir deteriorated condition. The wingwalls courd probably bereplaced, but the problem would be tying them into the weÍr andproviding stability for the spiltway. This alternatÍve doesaddress the undermining of the spillway, but the wingnvalls would.not be improved.

Cost Estimate - Àlternative Ttro

MobilizationTraveISI{C LaborSWC EquipmentGroutMÍsc. Materials

I LS $1,500.001 LS 2,000.001 LS 7,000.001 LS 2,500.007s cY 80.00I LS 500.00Subt,otalEngineerÍng 10tÀdmÍnístration 10tContingencÍesTotal

$ 1,500.002,000.007,000.002,500.006,000.00

500. oo$19,500.00

1r950.001r950.001,600.00

$25, 000 . 00

Àlternative ThreeConstmction of a New Spil]-way:

The third alternative consists of replacing the existingspilrway with a new outret structure. A corrugated metal pipeand concrete chute r'rere analyzed. The outlet structure desÍgnwill be addressed in the fórrowing sections of hydrorogy,hydraulics, and prelimi-nary design. A preliminary cost estimatewill be also provided for each structure.

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Ilvdroloov:PrecipÍt,at,ion design amounts were determined

was classified. Outlet, works are requiredcapacities such that they pass the runoff fromevents as suggested by its classificatÍon.

once the damto have flow

precipitation

Based on the North Dakota Dam Design Handbook, therequirement for a class rr dan is t,hat the dam is to withst,andthe S0-year event without overtopping. A 6-hour rainfall, 10-dayrainfa1I, 24-hour rainfall, and 10-day snowmelt precipitationtables were used for the 50-year event. The 6-hour raÍnfallevent lras found to be the critical event for the watershed andwas used for dam design crÍterÍa. Table 3 shows the resultingpeak inflows and total volumes for a S0-year event.

Table 1 - Peak fnflows and Voh¡mes for Design50-Year EventTotaIFreguency Peak fnflows fnflo¡r Volume peak Stage(cfs) (acre-feet) (fr) ms1

6241010

-hour rainfall-hour rainfali-day rainfall-day snowmelt

L9241601L7 441304

756149826442424

1845.441844.901845.131844.33

Ilydraulics:Àn area-capacity curre for the reservoir vras developed

through a fÍeld survey. The normal surface pool elevation is1840 msl which covers 28.L acres, a vorume of 2os acre-feet,maximum depth of L8.7 feet, and an averaqe depth of 7.3 feet. The

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mini¡num lake elevation recorded is 1821.3 msl. The top of theemban}¡nent, is at an elevat,ion of 1849 nsl.

The normal surface pool elevatÍon will be constant for eachof the proposed outlet structures. The exÍsting dam does not,have an emergency spillway and based on the classificatíon, anemergiency spillway is not required. Table 2 shows the areacapacity for the new dam site.

Tab].e 2Àrea-Capacity Cunre

( feet) (acres) (ac-ft)L8251830183s184018451850

229I41

3I15284150

63495

2053?9508

The elevation capacity curve and the inflorr hydrographs rúerethen used to determine rese:¡¡oir stages and outflow hydrographsby routing the inflows through the reservoir using the HEC-Imodel. Th3 outflow hydrographs were used to determine the desÍgncriteria for the outlet structures.

Preliminar¡r DesignÀ. Ct-fP Spillway.

Two corrugated metal pÍpes L20 feet in length and 6 feet indÍameter will be considered as a replacement for the deterioratedspillway. The inlet would have a l2-foot. drop and a 96-inch

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intake opening with trash guard. The inlet will have a crestelevation of 1840 msl with the invert, of the cMP's at, elevation1828 msI. The cMP's will be laid at a slope of 3.33 percent withthe outlet at elevatÍon L824 msl. The outlet structure consÍst,sof a standard cantilevered oútlet wíth st,Ítting basin (See Figure3). The embankment would have a 14-foot wide top at, 1849 msl,with 3:1 s j-de slopes that will tie into the existing e¡nbanl¡cnent(See Figure 4).

The deteriorated spillway would be removed and disposedon-site or haured avray. The oLd spillway rocation would beplugged wíth earth-filled material. A soil investigat,ion may berequired to find proper filt material for the embankment.Àdditional riprap wiII be needed on the face of the embankmentfor erosion protectÍon.

The critical event, for design criteria nas the 6-hourrainfall 50-year event. The peak outflow through the pipes wasL245 cubic feet per second (cfs). fnflow from the 50-yearraÍnfall event will cause the reservoir to rise to an elevationof L847.4 nsl. The top of the embanlrcnent (f849 mst) would not beovertopped by the S0-year rainfall event.

A low-level drawdown system will also be implemented. Àrow-Ievel (hlpotimnetic) water guality contror structure wouldimprove the water quality by removÍng stagnant water from the

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Its@I

i!l

2:1

tocAtBTRîI

a:lztttto

PROFILE 6' CMP

tæ Lr. cr DlA c.rP. !.o¡ g.oFE

IO æ¡t¡Figure 3

181

1

3:1

3:l1834

1840

1840

18341828

1822

J:1

NO SC,AI.EFioure 4

P

PLAN VIEII TIIO 6' CMP

bottom of the reservoir. The total cost of for ClfP spillway is$145,000.

Cost Estimate'- ÀIternative 3À

Mobilization![ater ControlDenolish SpillwayExcavation72-inch Dia. CIIP96-inch DiameterInlet StructureEmbankmentRR Filter MaterialRock RiprapCathodic Protect,ÍonLow-L,evel Drawdown

SystemSeedÍng

1I1

5r000240

28r0oo

L20400

1

LSLSLSCYLF

$10,000.00 $15 r 000.0010,000. 00

1.5075.00

10,000. 0015,000. 0010,000.00

7 r 500. 0018,000. 00L216

110

3

EaCYCYCYLS

6 r 000. 002.OO

15.0025.00

3,700.00

,000 .00,000 . 00,800.00,000.00,700 .00

6,000.001,000.00

s111,000.0011r 000.0011r000.0012 ,000 .00

1 LS 6,000.001 LS 11000.00SubtotalEngineering 10tAdministration 10tContingenciesTotal $145,000 . 00

B. Concrete Chute.À concrete chute would be another opt,ion for replacement of

the deterÍorated spillnay. The chute would be located in thesame area as the original spillway. The concrete chute would be30 feet wide' 150 feet in length, and have a crest el-evation of1840 msl (See Figure 5). The concrete chute would have a heightof I feet. The wingwalls on the concrete chute wourd be at a3H¡1V slope tying into the top of the embankment at 1849 msl (SeeFigure 6). This alternative also includes a low-level drawdown.

t

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It\)F

I

1r

l:1 -zN

CONCRETE CHUTElr0 sGA¡l

PROFILEFigure 5

INJN)I

181

1

1834

1840

1840

J:1

3:l 18341828

1822

CONCRETE CHIJTENO SCALE

Figure 6

PLA}I VIEII

The crit,ical event for design crit,eria was the 6-hour50-year rainfall event. The peak outflow over the chute was 1887cfs. Inflow from the 50-year event, will cause the reservoir torise to an elevation of L843,2 msl. The top of the enbanlsnent(1849 msl) would not be overtopped by the S0-year event. Theprelininary estimated cost' for a concrete chute is $315r000.

Cost Estímate - Alternative 38Ttern Ouanti t-¡z IIn i t- Cost- ]Fotal

ÌlobilizationI{ater ControlDemolish SpillwayExcavationConcreteResteelEmbankmentRRR FilterRock RiprapLow-Level DrawdownMisc. MetalsSeedingSteel Sheet Piling

4 ,36s

73,0004,000

200600

11I

360Subtotal

$15,000. 0025,000.0010,000.00

r..502s0.00

0.502.00

15.0025.00

I,000. 0012,000.001,000.00

25.00

,000.00,000.00,000.00,750.00,250.00,500 . 00,000.00,000.00,000.00,000.00,000 . 00,000 . 0o

9 ,000 . 00$240 ,000 . 0024,000.00

24,000.0027 . OO0. OO

152510

59136I

315It2

1

$11I

500

LSLSLScvCYCYCYCYCYLSLSLSLF

EngineerÍng 10tÀùninistration 10tCont,ÍngenciesTotaI $315 r 000.00

Àlternative FourConstruction of New Dan:

The fourth alternative would be to construct a new damdownstream from the existing dam and use the existing enrbanl¡cnentfor a settling basin. The dam would be located one miledownstream from the existing dan site. The new dam location isin a rural area where there is little probability of futureresÍdential development downstream of the dam site. FaÍlure of

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this dam could result in damage to agricultural land and townshÍproads, however, no loss of life ¡could be expected. Therefore,the new dam is considered a low hazard dam. The embankmentheight is 36 feet, classifying the dam as classÍfication IfI,according to t,he North Dakota Dam Design Handbook (see Figure 71.

Hwdroloar¡:Precipitat,íon design amounts were determined once the dam

was classified. Outlet, works of a dam are requÍred to have flowcapacities such that they pass the runoff from precipitationevents as suggested by its classi-fÍcation.

Based on the North Dakota Dam Design Handbook, therequirements for a class rrr dam are: 1) the principal spilrwaymust pass the flows of a 25-year event without the use of anon-structural emergency spillway, 2) the emergency spiltwaymust pass the flows of a 100-year event within accept,ablevelocity limÍts | 3) the dam is to withst,and the 0.3 pMp event,without overtopping. À 10-day rainfall, 24-hour rainfall, 6-hourrainfall, and 10-day snowmelt precipitation tables were used forthe 25-year and 100-year events, and a 0.30 p!{p event. The6-hour rainfall event was found to be the critical event for thewatershed and rras used for dam design cri-teria. Table 3 showsthe resulting peak inflows and total volumes for 6-hour rainfallevent,s.

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10' CDNTOUR INTERVALSA

PROPOSED DAM

¡IIN)(¡

I

D

ELEV,791t796îaootao6taîo,af6ta20,425I ¿'30ta36ta40

ACRESo,.o5.9

14.626.Ogf.95î.156.29l.47t.2ao.o

AC.FT.o.o2.O

t 9.g70.3t71.89f6.4

624.9749.7I OAA.7t427.7f 805.7

.ÅREA CAPACITY TABLEPROPOSED DAM

F

Tab1e 3 - Peak fnflows and Volumes for DesignFrequency 6-Hour Rainfall EventEvent Peak Inflows Total ïnflow Volune

(cfs)25-year

10O-year0.3 PTIPL42722845783

( acre-feet )754

12083203

An atea-capacity curve for the neril dam site nas developedthrough a field survey. The elevation capacity curve and theinflow hydrographs were then used to determine reservoir stagesand outflow hydrographs by routing the inflows through thereservoir using the HEC-I rnodel. Table 4 shows the area capacityfor the new dam site.

Table 4 - Ne¡r Dam Sítelll av.af inn Àrea Vrrl rrma(feet) (acres) (ac-ft)L79L179518001805181018151820L8251830183s1840

1.5.

L4.26.O31. 951.155.264.47L.280. 0

003354977

0095

2.19.70.

L7L.315.523.789.

1088.L427.71805.7

Principal Spíllway:Several alternatives were evaluated for the desÍgn of the

princÍpal spillway. The alternatives included a 6-foot diameterreinforced concrete pipe (RCP), a 5 tf2-foot RCP, a S-foot RCP,

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and a concrete chute. The alternatives were evaluated byconsidering flow capacity, hydraulÍc efficiency, and preliminaryconstruction costs. Based upon the criteria, the 5 Lf2-fooE RCPwas chosen for the principal spillway design. Table 5 shows theresults of the hydrologíc study for Èhe proposed 5 Lf2-footdiameter RCP (See Figure I and 9 for Hydrographs).

Table 5 - Results of Hydrologic StudyProposed 5 Lf2-f:oot Diameter RCPEvent fnfl-ow Out.flow Staqe

(cfs ) (cfs) (feet)25-year 6-hour rainfall

100-year 6-hour rainfall0.3 PTIPL42722845826

73319385823

1835.001836.511838.07

The principal spillway inlet will be at an elevation of 1830msl. The proposed reservoir will have a surface area of 64.4acres, and a volume of 1088.7 acre-feet. The maximum depth ofthe resen¡oir wÍll be 39 feet and have an average depth of 15.9feet.

With the normal surface level at 1830 msl, an island will beformed on the reservoir. The island wiII have a peak elevationof 1845.5 msl, and cover an area of 3.2 acres at, the normal watersurface Ievel.

The principal spillway will consist, of a inlet. boxstructure, 5 I/2 foot RCP, and plunge pool (See Figure 10). Thespillway would have a 24-fooX drop inlet with the pipe invert at

-27-

- inflowoutflow

WeLk Dum Hydrogrrylls25 Yecr 6-Hour Roinfoll

1 600

1 400

1 200

1 000

800

600

400

200

0

F

L

0W

I

N

C

FS

FL0

2400

2200

2000

1 800

0 5 r0 t5 20 25TIME IN HOURS

100 Yeor 6-Hour Roinfoll

15 20 25TI]\/|E IN HOURS

-28-

J0 J5 40

\/v 1600

I

N

CF

S

1 400

1 200

1 000

800

600

400

200

0

0 5 10 i0 J5 40

- inflowoutflow

FL0W

I

N

cF

6000

5500

5000

4500

400¡

J500

J000

2500

2000

r500

Welk Dam Hydrogrwh0.3 PMP

15 20 25TIMT IN HOURS

5 1000500

0 05r0 30 J5 40

- inflow--' outflow

-29-

I(,oI

e

I

18,t0

6'

JÉt

qJrcfT CüIAR

20t LF. 8t'RCP

r820

LOCAL 8ERil

1Eot

CRO'ND

?t t: :l

L,I.J \conr ÏRENCil

TRANTSVERSE PROFILE OF DAMAT PRINCIPAL SPILL1VAY

\,TELK DAM SIVC# 400

1806 msl. The RCP Ís 208 feet, in length wit,h a 2.5 percent slopewith the outlet invert, at elevation 1801 msl. The reinforcedconcrete pipe will consist of thirteen - 16-foot sections. Withinthe length of the spillway there wiII be 6 reinforced concreteant,i-seep collars. The outlet structure consists of a st,andardcantilevered out,let with st,illing basin.

A low-level drawdown pipe will be implemented to dischargewater into the - principal spillway structure. The low-leveldrawdown structure or hlrpolirnnetic discharge structure isdesigned t,o counteract accelerated aging in reservoirs. TheIow-level drawdown structure removes nutrient-rich water from thebottom of a thermally stratified rese:rroir, J.eaving the betterquality water behind, and thus increasing the usefulness and lifespan of the reservoir. Improved water quality conditions result,in a posit,ive benefit to the fishery and to all otherrecreational uses.

Emergency Spillway:A grassed emergency spillway will be located on the west,

side of the reservoir discharging to a separate drainage basin tothe west. The emergency spillway will have a bottom width of 200feet and a crest elevation of 1835.5 msl. The reservoir covers72.L acres and the capacity is 1463.5 acre-feet at the emergencyspillway crest. The suggested design criteria for establishingthe crest of the emergency spillway is based on the 25-yearevent,.

-31-

The location of the emergency spillway is a natural swalethat, will dÍscharge to the west of the reservoir. The existingpeak elevation is 1837.3, with a base width of 20O feet,. Thespillway crest would be excavated to 1835.5 msl, with the sídeslopes of 3:1, and tying into the existing contours to preservethe natural ground wÍth the minimum amount of disturbance. A onepercent, slope 5-s designed for the downstream and upstream channeltying Ínto existing ground at 1830 msl (See Figure 11). Seedingthe excavated area would be required to prevent soil erosion tothe emergency spillway channel.

Enbanlment Desigm:The nen dam embankment would be a rolled earth-fill type

whose top elevation is 1840 msl. The 49-foot high embanlcrnentwill have 3H:1V upstream slope and the downstream face will havea slope of 3H:1V. The top of the embankment Ís 800 feet long andL7 feet wide. The criteria for the dan is prelim5-nary and a soilinvest,igation will be needed to verify site and constructiondata.

Rock riprap will be provided for protection to the upstreamface of the dam. ft would be placed from 5 feet, below thepermanent pool elevation to 5 feet above. Flood resistantveget,at,ion would need to be planted above the riprap to protectthe emban}cnent, for those days that the water is more than 5 feetabove the permanent pool elevation. Rock riprap would consist ofhard, durable rock, well graded; placed at a thickness of 18

-32-

EMERGENCY SHLLVAYPROPOSED ÐAM o

NO SCALE

200.

.$¡

t882

-33-11

inches on 6 inches of well-graded gravel fÍIter material. Theembanlrcnent would need 500 cubic yards of riprap and 300 cubicyards of filter material to be placed for vert,ical heÍght of 10feet along the ent,ire dam face. Rock riprap will also be placeddownstream from the outlet structure and in other areas whereerosion may occur.

The existing embankment from the dam upstream would bebreached and the dam would be used as sedÍmentation pond.Lowering the embanl¡ment to an elevat,ion of 1830 msl would leavethe reservoir with a depth of 8.7 feetr ên area of 8.2 acres, anda total volume of 34 acre-feet,.

Cost, Estimate - Àlternative 4Tt-e-m Ouantitw Unit Cost lfotal

ltobilizatÍonWater ControlStripping TopsoilCore Trench

ExcavationEmbankmentI{ater for

CompactionConcreteReinforcing Steel66-inch RCPLow-I¡evel DrawdownDrainage PipingDrain F111Rock Riprap FilterRock RiprapMisc. Met,alsSeeding

2,000 II GÀL400 cY40,000 LBs208 I,F1.- LFlLS500 cY800 cY3,000 cY1LS20 Ac.

Subtotal

$10,000.0020,000.000.252.25L.20s.00

300.000. s0

25.006,000.00

12,000.0020.0012 .5020.00

10,000.00300.00

s.10,000.0020,000.006,800.00

18r000.00180,000.00

10 r 000.00L20 | 000.0020,000.005,200.006,000.00

12,000.0010,000.0010,000.0060,000.0010,000.00

6 ,000.00s504,000.00

50,400.0050,400 . 00so .200.00

11

27 ,2008r000

150 r 000

LSLSSY

CYCY

Engineering 10tÀdministration 10tContingenciesTotal

-34-

s655,000.00

V. EMIIRONUENTÀL ÀSSBSSI{EI{T

The project would have minÍmal environmental impacts.Replacing the principal spillway as in Àlternative Three wouldimprove the safety due to preventÍon of structural failure andsoil erosion. Iûhile breaching the embanlrcnent would provide lessflood protection for downstream areas and leave the surroundingarea short of water supply during drought times, construction ofa new dam downstream would alter the landscape in certain areas.Àreas affected by the construction of the embanlcnent, would needto be re-landscaped and reseeded to native g:rass.

Loca1 changes in air quality and noise levels would benoticeable during the construction phase of the proJect. rf theproJect, is pursued, the State Historical Society should becontacted concerning any historical, archaeologicalr or culturalresources that nay be affected.

-35-

VI. IJAI{D RTGITTS

The Emmons County Ì{ater Resource District and the State ofl{orth Dakotá obtained the easements for the land to be flooded orinundated by the construction of Welk Dam in 1936. No additionalland will need to be obtaíned in Alternative One, T!Ío, and Three.Land rights, either by purchase or easement, will be required forÀlternative Four, the construction of a new dan. The neÌr sitewill consist, of approximately 82.7 acres in section 33, Township131 North, Range 77 l{est. The cost for this land acquÍsition isnot, figured into the cost estimate proposal for the alternative.rf the alternative for constructÍon of a new dam is pursued, it,is recommended that the ent,ire reservoir be fenced. Fencing willgreatly enhance the recreational aspect,s of the project,Íncluding improved water quality conditions.

-3 6-

VII. SUUT.ÍARY

Welk Dam was constructed in 1935 and the last recordedrepair work that has been done on the spillway was in 1958. Thus,the exÍsting spillway is in poor condition due to the extensiveundermining, cracking, and deterioration of the wingwalls. TheEmmons County IÍater Resource DistrÍct entered into an agreement,wíth the North Dakot,a State Water Commission and the North Dakot,aState Game and FÍsh Department to investigate the feasibílity ofrepairing or replacing Welk Dam.

Four alternatives are considered that, will either improvethe existing spillway or construction of a nerr darn downstream.The first alternative consists of breaching the existingembanlrcnent and draining the resen¡oir. The second alternat,iveconsists of the use of guníte to restore the existing spillway.Replacing the spillway with a new outlet structure is the thirdalternative. The fourth alternative to be considered will be theconstructÍon of a new dam downstream.

Às part, of the agreement, the North Dakota State IùaterCommÍssion's survey crew did a field survey of the existÍng site,and the proposed downstream dam site for area capacity data. IlelkDam has a normal pool surface of 1840 msl, with a Ogee weír asthe princÍpal outlet structure. At this elevation the reservoircovers 28.2 acres, maximum depth of 18.7 feet,, a total volume of205 acre-feet, and with an average depth of 7.3 feet. The top of

-37-

the embankment is at an elevat,ion of 1849 msl, with no emerçfencyspillway available.

An on-site structural investigation Ìùas done by the StateIlater Commission's construct,ion creïr to provide information toamount, of undennining that has occurred to the spillway.InspectÍon of the spÍllway was performed by drilling borings(2-inch holes) across the face of the spillway. The largest voidÍs 27 inches deep, with an average void depth of 13 inchesthroughout the spillway. The voids r{ere located on the west halfof t,he spillway. There nere no voids discovered on the easthalf.

The first alternative dÍscussed is the breaching of theembankment and drainÍng the reservoir. This could be donei¡nmedÍately, preferably in the fall before the next springrunoff.

Breaching the embankment and draining the rese¡r¡oir wouldeliminate the risk of damage caused by a danr failure. However,the loss of the reservoir for water supply duríng drought,conditions and recreatÍon may not outweigh the circumstances. Thebreached area would be available as a site for a netr spittway¡vhich might be built at some later date. The total cost, for thisalternat,ive is $18,000.

-38-

The second alternative consists of the use of gunite torestore the spillway. The amount of gunite that would be neededto fill the voids is est,Ímated at ?5 cubic yards. The total costestimate for rehabilitation is $25r000. This rehabilitationwould not, include work done on the wingwalls of the spÍllway.RehabilÍtation of the wingwalls would be impossÍble because oftheir deteriorated condition. The wing-wa1ls could probably bereplaced, but the probrem wourd be tyÍng them into the weir andproviding st,abilizat,Íon for the spillway.

The third arternative is repracing the spiltway with a newoutlet structure. The out,let st,ructures to be considered arecorrugated metal pipes and a concrete chute. The deterioratedspillwa1r would be removed and disposed on-site or haured away.The outlet structure would be located in the same location as theexist,Íng ogee weir. Because of the classificationr'an emergencyspillway is not, required for the dam. À tow-rever drawdownsystem wiII be implemented for removing stagnant water to improvewater quality.

Two corrugated metal pipes L20 feet in length and 5 feet indiameter, will be consÍdered as a repracement for thedeteriorated spillway. The inlet ¡uitt have a crest elevation of1840 ms1, with the invert of the CMP's at elevation 1828 msl. Thepipes wirr be laid at a srope of 3.33 percent wíth the out,let atelevation L824 msl. The outlet structure consists of a standardcant,ilevered outlet wÍth stilling basin. The embankment would

-39-

have a L4-foot wide top at 1849 msl, with 3:1 side slopes thatwill tie into the existing emban}cnent. The total cost forreplacing the spillway with two CMp,s is $1451000.

À concrete chute would be another option for replacement ofthe deteriorated spillway. The chute would be located in thesame area as the original spillway. The concrete chute would be30 feet wide, 150 feet, Ín length, and have a crest elevation of1840 msl. The concrete chute would have a height of I feet. Thewingwalls on the concrete chute would be at a 3H:1V slope tyingint,o the top of the embankment at 1849 msl. The preliminaryestÍmated cost for a concrete chute is $3151000.

' The fourth alternative would be to construct a nen damdownstream from the exÍstin*g dam and use the exist,ing embankmentfor a settling basin. The nen dam,s height 'is 36 feetclassifying the dam as classification IfI, according to the NorthDakota Dam Design Handbook.

The principal spillway inlet will be at an elevation of 1830msl. The nevr formed reservoir will have a surface area of 64.4acres, a volume of 1088.7 acre-feet. The maximum depth of thereservoir will be 39 feet and have an average depth of 16.9 feet,.I{ith the normal surface level at 1830 msl, an island wilt beformed on the reservoir. The island wilt have a peak elevationof 1845.5 msl and cover an area of 3.2 acres at the normal ¡ratersurface level.

-40-

The prÍncipal spillway wÍll consist of a inlet, boxstructure, 5 Lf2-foot RcP, and prunge pool. The spÍllway wouldhave a 24-foot drop inlet with the pipe invert at 1806 msl. TheRcP is 208 feet in length with a 2.5 percent srope with theoutlet invert at elevat,ion 1801 msl.

À low-level drawdown pipe will be ímplemented to dischargewater into the principal spillway structure. An emergencyspillway will be located on the west side of the reservoirdischarging to a separate drainage basin to the west. ThecriterÍa for the dam is prelinÍnary and a soÍl invest,igation wiltbe needed to verify site and construct,ion data.

The existing embanlcnent, from the dam upstream would bebreached and the dam would be used as sedimentation pond.Lowering the embanlcnent to an elevation of 1830 msi would leavethe reservoir with a depth of 8.7 feetr ôn area of 8.2 acres, anda total volume of 34 acre-feet.

The cost estimate for a new dam would be $6551000. Landacquisition and the soÍI investigation are not figured into theengineer's cost estimate.

-4L-

VIIT. RECOüTTEIÙDATION

The existíng spirlway is in poor condition. Extensiveundermining to the weir and deteriorating wingwalls is affectingthe integrity of the dam. The spillway should be eitherrepaired, replaced, or the dam breached. Several alternat,iveshave been studied and are being proposed as solutions to preventthe collapse of welk Dam due to a high runoff event. The repaÍrof the existing spillway, construction of a nerr spÍllwayr o! newdam locat,ed imnediately downstream are acceptable from anengÍneering standpoint. The estÍmated construction costs foreach alternative are substant,iatly dj-f ferent,.

Cost, Estimate - AlternativesLife

Breach DamRepair of Existing SpillwayNew Spillwaya) ClrP SpÍllwayb) Concrete ChuteNew Embanl¡cnent,

$12

8r0005r000

145, 000315, 000655, 000

(years )Life5-10

20-30s0-60s0-60

ff the Emmons County Ttater Resource District, does not repairor replace the spillway, it Ís recommended the embanlment bebreached this falr at a cost of $18r000.00. The decision toproceed with one of the alternatives is the responsibitity of theEmmons County I{ater Resource District.

-42-

TìI8ITAEE)V - V XIgNãddTI

SI{C Project #400January 11, 1991ÀGREEUENT

fnvestigation of Repairing or ReplacingÌfelk Dan.. .?

I. PÀRTIESTIIIS àGREExEI{[T is between the North Dakota State Water

commission, hereinafter conmission, through its secrétary, Davidsprynczynatyk; the North Dakota state Game and Fish Department,,hereinafter Department, through its commissioner, Lloyd Jones;and the Emmons County Water Resource District,, hereinafterDistrict, through its Chairman, Glen McCrory.

II. PROJECT, pttRpOSE, ÀtID LOCÀTIONThe District, and the Department have requested the

comnission to 'investigate the feasibility of repairing orreplacÍng of ltelk Dam. The darn is located in sect,ion 33,Township 131 North, Range 77 lüest, near strasburg, Nort,h Dakota.The purpose of this agreement is to acquire the propertopographic data necessary for preliminary design to repair andimprove the existing dam, and a prelÍmÍnary design for a new damdownstream.

IIT. PRELIT,ÍINÀRY I}T\IESTIGÀTIONThe parties agree that further information is necessary

concerRing the proposed project. Therefore, the CommÍssion shallconduct the following:

1

1

3

2

A field survey of the existing embankment,and the proposed new dam site whichtopographic data and area-capacity data;À- study of the hydrorogy of the watershed upstream ofthe dam;

reservoirincludes

necessary toflood throughA prelininary design of the outlet workssafely and effS-ciently pass the designthe existing dam and the proposed new darn;Preliminary cost estimates for thereplacing of the dam; and

4. repairing orç Prepare a prgliminary engineering report presenting theresults of the investigatÍon.

rv. cosrsThe District and Department shalr each deposit SlrB00 with

the Com¡¡ission prior to investigation commencement to help defraythe cournissions costs assocÍated ¡vith this invest,igation.

V. RIGIITS-OF ENTRYThe District agrees to obtain written permíssion from any

affected landowners for any fíeld Ínvestigat,ions by theCommission, which are required for the preliminary investigation.

V. INDEMIIFICATTONThe District hereby accepts respons5-bility for and holds the

commissÍon, the Department, their emproyees, their agent,s, theSt'ate Engineer, and the Corunissioner free from all claims anddamages to pubric or private property, rightsr or persons arisingout of -this investigatÍon. In the event a suit is initiated orJudgment rendered against the Commission, the Department, their

-2-

employees, or agents, the District shall indennify them for anyJudgment arrived at or Judgement satisfied.

VTT. CHÀ¡IGES TO Tffi ÀGREET{ENTChanges to any contractual provisions herein wilt not be

effective or binding unless such changes are made in writing,signed by aJ.I parties and attached hereto.

NORMI DÀKOTÀ STÀTE TIÀTERcoulrrssloNBy:

NORTH DÀKOTÀ GÀ¡TB ÀND FISHDEPÀRTMENTBy:

(ù"ilU*r-t*,rxÁDÀvr D' tr/' SÉsyfl(zyNfrfKSecretary

DÀTE:

l8 i",^ ll

LLOYDCommis

DÀTE:

s

L 4

wTTNESS:^^[ü; & F;ü

WITNESS:

EUIIONS COTINTT I{ÀTER RESOT]RCEDISTR,ICTBy:

c

GLENChairman

DÀTE:

t f zr/ qtWITNES

-3-

ÀPPENDIX B - IÍÀTBR QUÀLIrr ÀNÀI,YSIS

"r'.iiiiìr¡

NORTH DAKOTASTATE DEPARTMENT OF HEALTHAND CONSOLIDATED LABORATORIESSlate Capitol6O0 E. Bouleva¡d AvenueEismarck. Noth oakota 5g50$0200 ENVIRONMENTAL HEALTH SECTION

120O Missouri AvenueP.O. Box 5520Bisrna¡ck, Norúr Dakota SSSOZ-SSZOFax S701-258{052

June LL, 1991

Stan HansonDivision of EngineeringNorth Dakota State Water Commission900 East BoulevardBismarck, ND 58505Dear Mr. Hanson:Enclosed are the results of the water quality samples collectedat tfelk Dam on May r4r 1991. These results are typical for mostsma1l reservoirs in the state. Please note the gieater ammoniaand phosphate concentratÍons at the five met,er-dépth interval.These greater concentrations are likery caused by the low dis-sorved oxygen at thÍs de¡lth. These results suggést a hlpo-limnetic wi.thdrawar wourd be a practical compoñent of aáy aamrest,oration effort on Welk Dam.For your informatÍon, Ilelk Dam will continue to be sampred thissummer as one of 30 lakes which will be assessed as part of theDepartment's Lake Vüater Quality Assessment Project. This assess-ment wiII also include a characterization of the lake's watershedin addit'ion to describing the current trophic stat,e of the lake.rf you have any questÍons concerning these results or the lakeassessment effort, please feel free to contact me ax 22L-s2I4.Sincerely,

ïü*ö-? cQ\)Michael J. EIIEnvironmental ScientistDivision of Water eualityMJE:krhEnc.cc: Fred Ryckman, Game and Fish Department - Bismarck

Gene Van Eckout, Game and FÍsh Department - Jamestown

EnvironnrentalEnforcement

701-?,2.4-32U

EnvironmentialEngineering

701-224-2U8

MunkipalFaclities

701-224-2J54

WasteÑ4anagom€nt701-224-23æ

WatorOuality

701-224-2354

North Dakota State Department of HealthDivision of t{ater Quality

Date {-tq -clt4

'rke or River Namen ?,i0-'-serverStoret No.

Time

-t'317L{t'4 :3

l.lor'th Dakota Stat e Depar.t ment of He¿r1thand Consolidated Labor.ator.ies

6/ 6/9LEmmons Cor-rnty

Log Number.: 91-RËgS Type: ÉDate Collected z 3/L4/9LTime CoIIec.ted: 14:3tZrSite: ¿813É5 t^leIk Dam

St^¡ of spillway deepesttrollected by: Mike EI1Comment s:

Result

Dat eTime

Rece i ved :Reee i ved :

=r/ t=/gLo-qE

at'e å

fttalyte llncertainty Date Tire AnalystCopper (Cu) (Zinc (Znl tBeriur (Ba) (Sodiur (Na) (llagnesiur (üq) (Potassiru (Kl tCalciu¡ {Ce) (Hanganese (!tn) (Iron (Fe) (Chro¡iur (Cr) (fusenic (As) (Seleniur (Sel {Cadriur (Cd) (Lead (Pbl {$loride {Depth {A¡ronia fi) {pll {Cartonate (C03) tBicarbon¡te (!Etll) {llydroxide (flll ,{Total ßlkalinity (CaC{l3l tCondrctivity (Fto:phatr (Totall (Pl {$¡lfate as (Sl{l (l{itrate + llitrite {N} Tot {Total Kjetdahl Nitrtqen (Total llardness (as CåC03) tCetion Sur (0nion Sur (Difference (Percent Difference {Fercent Sodiur {Sodiur Adsorption Ratio (Total Dissolved Solids(C) t

uæ)u3B)u56)t¿il)tere]te19)re?0)læ5)ræ6)4te4l{133}413414148){t8e}5e17)9050)9085)93ffi)9310)9r'1,5)93ee)93¿51933r19{15}9{4e}95Ft)9fi5l9840)996)99le)9915Ì99e0)99e519930)9935)

(1443.æË¡TJ. rJ

3å7.39. eæ'ø49.30.0400. te6L,t7

13.3t

( 0.e?.?

13.01.90.@8.9ø

5e.sil.

0.505.

t907.0.6{8

5e3.0.015e.63

¿95.æ'¿3¿r.370.8561.96

73.69.46

læ0

9.04,5. t6

t

l,lor.ttr D;tkota State Depar-tment of Healthand Consr:Iicl .rted Labonatories

6/ 6/9tEmmon= Co'unty

9 1-RË31¿ì Ty Fe : Ê

Analyt e

Lo g ltlumber' :Date Col lected: 3/14/9LTime Collected: 14:31ãSite: 3813É5 tJeIk Dam

St¡ of spillway deepestColleeted by¡ Mike OlEsnComments:

Result

Dat eTime

at'ea

tlncertainty

Reee i ved :Rece i .¡ ed : =/

r3/9L6:55

5/?¿/911t?219t5tæ.1913t2Ll9Ls/ell915/e1/911t?vitst?u9Lst?vit61 3l9L5/30/9 I5t?IliL5t¿4t911t?øt9t5tæt9t5n4t9l5^6t915/15/915/t5/913/15/9 Ig/t5/9r5/15/915/15/915/15/913tt¿.t9t5/êr /9 I6t 4t9l

Date Ti¡e flnalystCopper (Cu)iinc (Zn)Bariu¡ {BalSodiur (l{a)llagnesiur {l{g)Potassiur (KlCalciur (Ca)lhnganese (l{n)Iron (Fe)$rroriu¡ (CrlArsenic (As)Seleniur (Se)Cadriur (Cd)Lead (Pb)ChlorideDepthÊ¡ronia (NlÉlCarbonete (fr131Bicarbonate (lEflillHydroxide ($l)Tatal ßlkalinity (Caü13)ConductivityPhosphate (Total) (FlSulfate as (S0{}Nitrate + l{itrite {Nl TotTotal Kjeldahl Nitr-ogenTotal llardness (as CaC03)Cation Su¡Anion Sur0ifferenceFertent DifferenceFercent SodiurSodiur f,dsorption RatioTotal Dissolved Solids{CI

( il39){ il30}( u56)( telllt tele){ t¿t9}( teze){ 1¿?5}( tæ6){ {te{}( 4133Ì{ 4134}t {l{8}( {l8e}( 5¿17)( gffi)t 9005){ 93ffi}t 9310)t 93151{ 9æ0}t 9335)t 9330Ìt 9+151t 9¡i0){ 9S7}{ 9515}{ 984e}( 996]{ 9910}t 99t5){ 9930}{ 99e5}{ 9930}{ 9935}

(1431.Êe.3

339.36.019.7{5.00.0810,145t.6t

t{. a4,

( 0.e1.9

13.65.00.Ê538.71

n.5{3.

e.806.

1796.0.79e

497,0.0{3¿t9

e6l.e0.49e0. g7

-e.3s5-0.9373.8

9. 13te50

ug/Lug/Luq/Lrg/Lrq/LtglLrg/Lrg/Lrg/Luq/luq/ Iug/Iuq/lug/Lrg/l!let ersrq/ I

rg/ I

5.03.5.79

æ.4e.9l:â

4. t50.0060.0130.503.0ó-.

0. e01.01.7

0.@

uq/Lug/Lug/Lrq/Lrg/Lrg/Lrg/Lrg/Lrg/Lug/lug/lug/lug/ Iug/Lrg/l!{et ersrq/I

rg/lrq/lrg/lrg/lrg/lrcllre/ Ire/ ItIrg/l

l0:51l0:51t0:El9: lZ9: t39: l€9: l?9:1?9: l2

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