Assessing Impact of Land Use and Climate Changes on River

Flow and Electricity Generation: Case Study at Citarum Watershed

of Bandung DistrictRizaldi Boer, Delon Martinus, Ahmad Faqih and Perdinan

Laboratory of Climatology,Department of Geophysics and Meteorology,

Bogor Agricultural UniversityE-mail: rizaldiboer@gmail.com

Study Site: Upper Citarum

• Covering an area of about 720 thousand ha• There are three dams ~ vital for meeting water demand of about

11 districts within watershed and 5 districts outside the watershed (north coast of West Java)

Cirata Dam

Saguling Dam

Jatiluhur Dam

Upper Citarum

05

1015202530354045

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

MonthIn

flow

(m3/

s)

El-NinoNormalLa-Nina

0

40

80

120

160

200

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

Month

Inflo

w (m

3/s)

El-NinoNormalLa-Nina

0

40

80

120

160

200

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

Month

Inflo

w (m

3/s)

El-NinoNormalLa-Nina

Monthly Average: Inflows to the three Dams in El-

Nino, Normal and La-Nina years

SAGULING

CIRATA

JATILUHUR/H. JUANDA

Inflow Local Inflows

Local Inflows

Sea level87.5 m

107 m

206 m220 m

625 m

643 m

Outflow from Jatiluhur

0

50

100

150

200

250

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

MonthIn

flow

(m3/

s)

Dry yearsNormal years

Outflow from Cirata

0

50

100

150

200

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

Month

Inflo

w (m

3/s)

Dry yearsNormal years

Outflow from Saguling

020406080

100120140

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

Month

Inflo

w (m

3/s)

Dry yearsNormal years

Outflows from the three dams in normal

and dry years

SAGULING

CIRATA

JATILUHUR/H. JUANDA

outflow

Inflowoutflow

Inflow

Sea level87.5 m

107 m

206 m220 m

625 m

643 m

outflow

Outflow and power generation

y = 2.2137x

y = 0.6942x

y = 0.4578x0

100

200

300

400

500

600

0 50 100 150 200 250

Outflow (m3/s)

Pow

er (G

Wh)

SagulingCirataJatiluhur

In extreme drought years the minimum

outflow from the dams were less than 50

m3/s)

Contribution of Saguling, Cirata and Jatiluhur HEP to Total Electricity

Production of HEPs in Jamali

The three HEPs contributes to about 74% of the Total HEPs of Jamali. The decrease in electricity production from these three HEPs will

have serious effect on economic activities. In drought years, HEPscapacity drops by about 60%. Many people believes that the

decrease in forest cover has deteriorate the impact

HEP Saguling28%

HEP Jatiluhur7%

HEP Cirata39%

HEP Area 35%

HEP Sutami4%

HEP Area 42%

HEP Brantas Non-Sutami

5%

HEP Area 22%

HEP Area 11%

HEP Mrica7%

Total HEPscapacity about

2520 MW

Total HEPscapacity about

2520 MW

Historical Land Use ChangesArea (ha) Percent change

‘89 ‘93 ‘99 ‘01 89-93 93-99 99-01 89-01

Bare land and shrub land 2694 5105 10469 11860 89.5 105.1 13.3 340.3

Agriculture area1/ 126536 124755 126501 126335 -1.4 1.4 -0.1 -0.2

Forest & vegetation covers2/ 46105 44182 34928 31951 -4.2 -20.9 -8.5 -30.7

Settlements 2639 3429 4547 5522 29.9 32.6 21.4 109.2

Urban and Industries 9030 9597 10627 11426 6.3 10.7 7.5 26.5

Dam/Lakes 312 247 243 223 -20.9 -1.5 -8.5 -28.7

TOTAL 187316 187316 187316 187316

Land Use

Change of Forest Cover in the Upper Citarum

0

10000

20000

30000

40000

50000

1989 1993 1999 2001

Year

Fore

st A

rea

(ha)

0

5

10

15

20

25

30

Percent of Total AreaForest AreaPercent of total Area

Critical Land in Citarum

0

30000

60000

90000

120000

150000

180000C

ritic

al L

and

(ha)

Ban

dung

*

Cia

njur

Kar

awan

g

Pur

wak

arta

Ban

dung

City Kot

aC

imah

i

Source: BP-DAS Citarum-Ciliwung (2003)

Community Perception• About 85% of respondents

stated that there is an increase in drought and flood frequency and intensity (Sulandari et al., 2004)

• Dialog between stakeholders and scientist at Bandung, it was suggested that at least 40% of watershed area should be maintained as conservation zone (forest cover) ~ It is believed that increasing forest cover will diminish the damage of flood and drought risk

• In 2010, government targeted to increase forest cover up to 48% of the total areas

0

10000

20000

30000

40000

50000

1989 1993 1999 2001

Year

Fore

st A

rea

(ha)

0

5

10

15

20

25

30

Percent of Total Area

Forest AreaPercent of total Area

Objectives• To evaluate impact of land use and

climate changes scenarios on river flow at Nanjung (Upper watershed) and on electricity generation

Citarum UpperCatchments

Step of Analysis

Historical Land Use

Observed Stream flow

VIC-BASIN Model

Historical Climate

data

Good?

Develop relationship between % forest

cover and base flow

Select the base flow

Change base flow and run off parameters

Land Use Scenarios

Downscaled GCM to

Study sites

Estimate base flow parameter

VIC-BASIN Model

Climate Scenarios

GCM

CLIMGEN

Evaluate the impact and develop

recommendation

Critical Land and Rehabilitation Plan for the Four Land Use Scenario for Upper

Citarum Watershed

0

20000

40000

60000

80000

100000

120000

140000

160000

2003 Mitigation 1 Mitigation 2 Mitigation 3 Government

Critical land Rehabilitation

Area

(ha)

Land Use Scenarios

LU-2001 MIT-1 MIT-2 MIT-3 RUTRShrubs 11862 9578 5 0 0Agriculture 126494 118465 124167 115736 77426Forest/Agroforest 31825 35921 45990 54445 89426City/Industrial areas 16912 22849 16931 16912 20016Dam/Lakes 223 503 223 223 448TOTAL 187316 187316 187316 187316 187316Percent forest cover (%) 17 19 25 29 48

Land use categoryArea (ha)

1989

ShrubsDam/LakeForest/AgroforestAgricultureCity/Industrial Area

Land Use Scenarios

17%: Baseline

19%: MIT-1

25%: MIT-2

29%: MIT-3

48%: RTRW

y = 0.521Ln(x) - 1.2047R2 = 0.9553

0

0.1

0.2

0.3

0.4

0.5

0.6

10 15 20 25 30Percent Forest Cover (%)

Bas

eflo

w P

aram

eter

Relationship between base flow parameter and forest cover

Citarum

Sumber Jaya

Comparison between observed and Downscaled

0

100

200

300

400

500

600

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

TIME (Month)

RAI

NFA

LL (m

m)

Observed DataDownscaled Data

Comparison between Observed (Above) and Downscaled Rainfall (Below)

DJF baseline rainfall from downscaling (1961-1990)

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

DJF baseline rainfall from observation (1961-1990)

MAM baseline rainfall from observation (1961-1990)

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

MAM baseline rainfall from downscaling (1961-1990)

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

JJA baseline rainfall from observation (1961-1990)

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

JJA baseline rainfall from downscaling (1961-1990)

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

SON baseline rainfall from observation (1961-1990)

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

SON baseline rainfall from downscaling (1961-1990)

106.6 106.8 107 107.2 107.4 107.6 107.8 108 108.2

-7.4

-7.2

-7

-6.8

-6.6

-6.4

-6.2

-6

-5.8

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

DJF MAM JJA SON

DJF MAM JJA SON

Projected Annual Rainfall at Citarum Watershed

2000

2100

2200

2300

2400

2500

2600

2700

Baseli

neA2 2

020

A2 205

0A2 2

080

B2 202

0B2 2

050

B2 208

0

Annu

al ra

infa

ll

Low Scenario

High Scenario

050

100150200250300350400

0 1 2 3 4 5 6 7 8 9 10 11 12

Month

Rai

nfal

l (m

m)

BaselineLow-ScenarioHigh-Scenario

GCM outputs from ECHAM model downloaded from Data Distribution Centre

Result of Validation Using CLIMGEN

050

100150200250300350

1 37 73 109

145

181

217

253

289

325

361

Julian DaySt

ream

flow

(m3/

s) Mean SS_UGCDObserved Streamflow

020406080

100120140

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

Stre

amflo

w (m

3/s)

Mean SS_UGDCObserved Streamflow

Distribution of stream flow under different land use and climate scenarios

0

0.2

0.4

0.6

0.8

1

1.2

0 200 400 600Discharge (m3/s)

Cum

ulat

ive

Pro

babi

lity

(%)

2001Mit-1Mit-2Mit-3RUTR

0

0.2

0.4

0.6

0.8

1

1.2

0 200 400 600Discharge (m3/s)

Cum

ulat

ive

Prob

abili

ty (%

)

2001Mit-1Mit-2Mit-3RUTR

0

0.2

0.4

0.6

0.8

1

1.2

0 200 400 600Discharge (m3/s)

Cum

ulat

ive

Prob

abili

ty (%

)

2001Mit-1Mit-2Mit-3RUTR

Baseline climate

Low Scenario High Scenario

Under baseline and low climate scenarios, increasing forest cover more than 20% and up to 47% of the total land areas would not change the distribution of stream flow Under high climate scenario, the distribution of stream flow under baseline and mitigation 1 land use scenario (percent land use cover is between 17% and 19%) was different from those under Mitigation 2 and 3 scenarios (percent forest cover is between 25% and 29%) and under RTRW (percent forest cover is 48%).

Relationship between Inflow, Outflow and Electricity Generation

y = 2.2137xR2 = 0.9903

0

50

100

150

200

250

300

350

0 20 40 60 80 100 120 140

Outflow (m3/s)P

ower

(GW

h)

y = 0.5693x + 42.757R2 = 0.99

y = 0.831x - 14.992R2 = 0.94

020406080

100120140160

0 20 40 60 80 100 120 140 160 180

Inflow (m3/s)

Out

flow

(m3/

s)

The result of analysis suggested that If the forest cover were not increased to more than 25%, the frequency of producing electricity power of less than 100 GWhduring dry season will increase under the three climate scenarios. The operation of this HEP in the dry season in critical to meet electricity demand during peak load