Impact of Climate Change on Hydrological Regime

and its consequences in Hydropower Production in

Dudhkoshi Basin, Nepal

JAYA R. PUDASHINE (Research Associate, Geoinformatics Center, AIT)

Prof Mukund.S Babel

Dr. Sangam Shrestha

Dr. Akiyuki Kawasaki

Email : jaya@ait.asia

Presentation Outline

Introduction

Study Area

Methodology

Results and discussion

Conclusion

2

Introduction

• Most economic, eco-friendly, mature and reliable renewable

energy source.

• Untapped hydropower potential need to be assessed and utilized.

• Traditional approach of HP planning /assessment provokes many

problems

• Climate change effect in hydropower planning

• Rapidly growing energy demand

• Green house gas emission

• Need of renewable energy source

Hydropower :

3

Objective

To assess the impact of future climate on hydropower

production in the Dudh Koshi Basin using GIS and

hydrological modeling

• To identify the potential sites for different type of HP plant

• To assess spatial and temporal availability of flow at

potential HP sites

• To develop high resolution future climate data for the study

basin

• To analyze the current and future energy production of the

basin

Specific objectives :

4

Study Area

Sapta Koshi Basin

Dudh Koshi basin

• Latitude : 2709’03” - 2806’24”N

• Longitude: 8626’2” - 8642’52” E

• Drainage area : 3718 km2

• Elevation ranges :436 m to 8848 m

• Average rainfall : 2000 mm/year

• Dry Season (Dec-May), Wet Season (Jun-Nov)

• Land use : Forest (31 %) , Snow (21%)

• Soils : LPi (44%), RGe (24%)

Dudh Koshi basin

5

Data Collected

Data Frequency Duration Resolution Source

Hydro-meteorological Daily 1976-2009 - DHM, Nepal

DEM 30m, 90m Aster GDEM, SRTM

Land use map - 2009 1:300 European Space Agency

Soil map - - 1:1,00,000 SOTER

Glacier map - - - Department of

Survey/ICIMOD

Inhabitant, Conserved

area map - 2004 -

Department of Survey,

Nepal

Glacier Information - - - http://www.rrcap.ait.asia/is

sues/glof/glof/Nepal/

Hydropower feasibility

report - 2010 -

Department of Electricity

Development, Nepal

6

Methodological Framework

INPUT

DEM, LU, soil and hydro-

meteorological data

PRE-PROCESSING PHASE

DEM processing, FDR,

FAC, stream definition and

stream order

Setting up criteria to identify

hydropower location

Storage capacity, inundation

area, HH affected, LU affected

Overlay DEM and stream

network

Ranking of the reservoir

sites

Estimate gross head, distance

between weir and HP

Analysis of the result POTENTIAL HP LOCATIONS

(ROR and Reservoir type HPP)

Setting up calibration and

validation of hydrological model

Daily discharge at all

potential location

Energy production estimation

for ROR and Reservoir HP

CURRENT AND FUTURE BASIN

ENERGY PRODUCTION

Reservoir simulation

Future climate data

FDC at 40, 50, 60, 95%

exceedance

Current climatic data

7

Bias correction of

RCM/GCMs

Criteria for site selection

ROR hydropower site:

• Minimum bed slope

• Distance between weir and hydropower plant

• Minimum drainage area

Reservoir hydropower site : o Physical criteria

• Order of stream

• Dam height

• Interval between reservoirs

• Storage capacity and inundation area

o Social criteria

• Number of household inundated

o Environmental criteria

• Area of forest inundated

8

Site selection hydropower

OUTPUT

Potential Location of ROR

9

OUTPUT

Potential Location of Dam/Reservoir

100 ROR and 3 Reservoir type Hydropower Potential Locations were identified

Hydrological Model : SWAT Setup

• Basin Area : 3718 Sq.km

• Sub basins : 102

• HRU : 1121

• 5 Rainfall station & 1 climatic station

• Elevation Band : 4-6

• Warm up period : 1977-1980

• Calibration Period : 1981-1990

• Validation period : 1991-1997

10

SWAT Model : Calibration and validation

Daily flow calibration result (NS=0.72, PBIAS=2.89, R2==0.75)

Daily flow validation result (NS : 0.70, PBIAS:6.27, R2=0.77)

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Basin Power Potential

Type No. of sites IC (MW)

ROR 97 2355

Reservoir 3 375

Total 100 2730

Type Avg Energy (GWh)

Dry Season Energy 3684

Wet Season Energy 10962

Total 14,646

Basin Energy Production

12

Total Basin Potential

Climate change analysis

RCM/GCMs Resolution Historical Run Future Simulation Scenarios

HADGM3-RA 0.440.44 1950-2005 2006-2100 Historical , RCP 4.5 & RCP 8.5

CSIRO-MK3 1.8751.875 1900-2005 2006-2100 Historical, RCP 4.5 & RCP 8.5

MRI-CGCM3 1.8751.875 1900-2005 2006-2100 Historical, RCP 4.5 & RCP 8.5

IPCC AR5 Models

Bias correction of RCM/GCMs (Quantile Mapping Method)

Base period ( 1976-2005) Future time period: 2030s ( 2011-2040) 2060s (2041-2070) 2090s (2071-2100)

13

Bias Correction of Temperature

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 11 12

Max

imum

Tem

per

ature

(°C

)

Month

'Obs Raw Corrected

0

3

6

9

12

15

18

21

1 2 3 4 5 6 7 8 9 10 11 12

Min

. T

emp

erat

ure

(°C

)

Month

Obs Raw Corrected0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25 30 35C

um

ula

tiv

e D

istr

ibu

tio

n F

un

cti

on

Maximum Temperature (°C)

Raw RCM

Corrected

Observed

GCM/RCM HADGEM3 CSIRO MRI-CGCM3

Temperature Max Min Max Min Max Min

R2 0.79 0.94 0.74 0.95 0.75 0.94

RMSE (mm) 1.81 1.09 2.03 0.99 2.04 1.11

Performance of bias correction

Comparison of observed max & min temp with Raw and corrected RCM

14

Precipitation correction

Comparison of observed, raw and bias corrected GCM/RCM for station 1202

Comparison of observed and bias corrected mean monthly precipitation for station 1202

0

2

4

6

8

10

12

14

16

18

20

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mea

n ra

infa

ll(m

m/d

ay)

Obs

Raw HADGEM3

Corrected

0

2

4

6

8

10

12

14

16

18

20

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mea

n r

ain

fall (m

m/d

ay

)

Observed

Raw CSIRO

Corrected

0

5

10

15

20

25

30

35

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mea

n ra

infa

ll(m

m/d

ay)

Obs

Raw CGCM3

Corrected

0

200

400

600

800

1000

1200

Jan-76 Jan-78 Jan-80 Jan-82 Jan-84 Jan-86 Jan-88 Jan-90 Jan-92 Jan-94 Jan-96 Jan-98 Jan-00 Jan-02 Jan-04

Bias Corrected Observed

15

0.0

1.0

2.0

3.0

4.0

5.0

2030s 2060s 2090s

Rel

ati

ve

cha

ng

e in

Tem

p (°C

)

HADGEM3 CSIRO CGCM3

Future climate prediction

0.0

1.0

2.0

3.0

4.0

5.0

2030s 2060s 2090s

Rel

ati

ve

cha

ng

e in

Tem

p (°C

)

HADGEM3 CSIRO CGCM3

Change in average temperature for different future period

Change in average basin precipitation for different future period

0

2

4

6

8

10

12

14

16

18

20

2030s 2060s 2090s

Rel

ati

ve(

%)

cha

ng

e in

pre

cip

ita

tio

n HADGEM3 CSIRO CGCM3

0

2

4

6

8

10

12

14

16

18

20

2030s 2060s 2090s

Rel

ati

ve(

%)

cha

ng

e in

pre

cip

ita

tio

n HADGEM3 CSIRO CGCM3

16

RCP 4.5 RCP 8.5

Future climate prediction

Relative change in seasonal mean precipitation for 2030s, 2060s and 2090s under RCP 4.5 and RCP 8.5 scenarios

-150

-100

-50

0

50

100

150

200

250

DJF MAM JJAS ON Annual

Ch

an

ge

in P

reci

pit

ati

on

(m

m)

-150

-100

-50

0

50

100

150

200

250

DJF MAM JJAS ON Annual

Ch

an

ge i

n P

recip

ita

tio

n (

mm

)

-150

-100

-50

0

50

100

150

200

250

DJF MAM JJAS ON Annual

Ch

an

ge

in P

reci

pit

ati

on

(m

m)

-200

-100

0

100

200

300

400

DJF MAM JJAS ON Annual

Ch

an

ge

in P

reci

pit

ati

on

(m

m)

-200

-100

0

100

200

300

400

DJF MAM JJAS ON Annual

Ch

an

ge

in P

reci

pit

ati

on

(m

m)

-200

-100

0

100

200

300

400

DJF MAM JJAS ON Annual

Ch

an

ge i

n P

recip

ita

tio

n (

mm

)

2030s 2060s 2090s RCP 4.5

RCP 8.5

2030s 2060s 2090s

17

SWAT simulation for future climate

Average monthly flow projected during 2030s under RCP 4.5 and 8.5

0

100

200

300

400

500

600

700

J F M A M J J A S O N D

Flo

w(c

um

/s)

Baseline

HADGEM3

CSIRO

CGCM3

0

100

200

300

400

500

600

700

J F M A M J J A S O N D

Flo

w(c

um

/s)

18

RCP 4.5 RCP 8.5

CC impact on basin power potential

During 2030s (2011-2040)

RCM/GCMs

RCP 4.5 RCP 8.5

2030s 2060s 2090s 2030s 2060s 2090s

HADGEM 3 5.06 % 0.41 % -7.80 % 10.54 % 6.25 % -5.49 %

CSISO 2.76 % 20.86 % 8.71 % 14.46 % 16.77 % 18.37 %

CGCM3 2.90 % 3.90 % 1.03 % 10.07 % 7.49 % 27.11 %

0

10

20

30

40

50

60

70

Dry Wet Total

% c

ha

ng

e i

n e

ne

rgy p

rod

ucti

on

HADGEM3

CSIRO

CGCM3

0

10

20

30

40

50

60

70

Dry Wet Total

% c

han

ge i

n e

nerg

y p

rod

ucti

on

HADGEM3

CSIRO

CGCM3

Relative change in seasonal energy production of total basin under climate change scenarios

Relative change (%) in total basin energy production relative to baseline for future period

19

RCP 4.5 RCP 8.5

Summary and Conclusion

• Total basin power potential : 2730MW (97 ROR and 3 reservoir hydropower plants)

• Temperature is predicted to increase up to 1C and precipitation is

predicted to increase up from 2 to 12 percent during 2011-2040.

• Total basin energy production is predicted to increase until 2040 by 5 % under RCP 4.5 ,14 % under RCP 8.5 and up to 23 percent until

the end of this century

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THANK YOU

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