ASSESSMENT OF WATER DEMAND AND SUPPLYUNDER FUTURE CLIMATIC CHANGE CONDITIONS

IN THE MAE KLONG RIVER BASIN, THAILAND

Presented by

Chollada Rojrungtavee

Thesis Advisor: Dr. Mukand S. Babel

FoS: Water Engineering and Management

INTRODUCTION

Climate change impacts on water resources

• Hydrological uncertainties

• Uncertainties in water availability and demand

• Hydroelectric power production

• Water quality

• Habitats to living organisms

Objectives:

• To estimate the current and future water demand of the main water consumption sector in Mae KIong River Basin under climate change conditions

• To evaluate water balance situation and power production under climate change condition using reservoir operation

INTRODUCTION: Scopes of Study

Study Area• Mae Klong River Basin

Reservoirs• Srinagarind reservoir• Vajiralongkorn reservoir

Main Water Consumption Sector• Irrigation sector (GMKIP)• Inter-basin transfer sector• Salinity control sector

Years of Consideration• Base year 2005• Future years 2025, 2050 and 2095

Greater Mae Klong Irrigation Project

• Total area– 4,833.44 km2

• Provinces– Suphanburi– Nakornpathom– Karnchanaburi– Samutsakorn– Petchburi

Water Consumptions

Domestic Industrial IrrigationInter-basin transfer to Ta-Chin

Total

Water Requirement (MCM/year)

47.04 64.42 2,276.32 4,270.04 6,657.82

Percentage of Water Requirement

0.71 0.97 34.19 64.13 100

• Main water requirements• Irrigation• Inter-transfer to Ta-Chin River Basin

• Domestic and industrial together is less than 2%• Salinity control requirement at estuary

• 1,571 MCM/year

METHODOLOGY

Study Area Identification

Future Irrigation Water Requirements in the Greater Mae Klong Irrigation Project for 2025, 2050 and 2095

Future inflows into Vajiralongkorn and Srinagarind reservoirs for 2025,

2050 and 2095

Reservoir Operation Model(HEC-ResSim)

Future water balance situation in Mae Klong River Basin

Irrigation Water Requirement

Irrigation Requirement Estimation

Calculation of Reference Crop Evapotranspiration (ETo)

Calculation of Effective Rainfall

Upland Crops

USDA Soil Conservative Service Method

For Ptot < 250 mm:Peff = Ptot (125 – 0.2 Ptot)/125

For Ptot > 250 mm:Peff = 125 + 0.1 Ptot

Lowland Paddy Rice

Soil-Water Balance Method

Penman-Monteith Method

)34.01(

)(273

900)(48.0

2

2

u

eeuT

GRET

asn

o

• The estimation of irrigation water requirements is separated into two methods for upland crops and lowland paddy

Inputs: Maximum and minimum temperature, relative humidity, sunshine hours and windspeed

Irrigation Water Requirement

Upland Crops

Calculation of Reference Crop Evapotranspiration (ETo)

Calculation of Actual Crop Evapotranspiration (ETc)

Calculation of Effective Rainfall

Calculation of Irrigation Requirement

Penman-Monteith Method

ETcrop = Kc . ETo

USDA Soil Conservative Service Method

IRReq = ETcrop - Peff

Irrigation Water Requirement

Lowland Paddy

Irrigation Requirement

IR = U + LP + WL + P – ER + S2 – S1

Where IR = irrigation requirement

U = crop water requirement

LP = land preparation

WL = normal water level

P = percolation

ER = effective rainfall

S1, S2 = storages

Irrigation Water RequirementData Requirement

Comparison of Average Monthly Rainfall over the Great Mae Klong Irrigation Area

0

100

200

300

400

500

600

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

Month

Ave

rag

e M

on

thly

R

ain

fall

(m

m)

2005_ECHAM4A2 2025_ECHAM4A2 2050_ECHAM4A2

2005_OBS 2095_ECHAM4A2

Rainfall

Irrigation Water RequirementData Requirement

Paddy_wet44.2%

Sugarcane22.7%

Sweet corn2.6%

Maize6.8%

Green bean0.4%

Mango23.4%

Paddy_dry61.3%

Sugarcane5.1%

Sweet corn13.3%

Maize0.5%

Asparagus7.7%

Green bean12.1%

Wet Season Crops• Paddy = 1170.3 km2

• Sugarcane = 600.5 km2

• Sweet corn = 67.7 km2

• Maize = 179.4 km2

• Green bean = 11.7 km2

• Mango = 618.6 km2

Dry Season Crops• Paddy = 1208.7 km2

• Sugarcane = 100.3 km2

• Sweet corn = 263.3 km2

• Maize = 9.1 km2

• Green bean = 239.5 km2

• Asparagus = 151.9 km2

Cropping area

Irrigation Water RequirementData Requirement

Cropping Pattern

Reservoir Operation Simulation

Vajiralongkorn dam Srinagarind dam

GMKIP

Inter-basin transfer to Ta-Chin River Basin

Salinity control

Gulf of Thailand

Figure 3.5 Configuration diagram for simulation of Mae Klong river basin – minor demand tributaries not included

Required inputs for the simulation:

• Inflows into reservoirs

• Reservoir characteristics

• Operation rule curves

• Basin water demand

Reservoir Operation SimulationData Requirement

Inflows into the reservoirs

Comparison of estimated and predicted inflows into Srinagarind reservoir

0200400600800

1000120014001600180020002200

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

Month

Vo

lum

e (M

CM

)

SN_estimated2005 SN_predicted2025

SN_predicted2050 SN_predicted2095

Comparison of estimated and predicted inflows into Vajiralongkorn reservoir

0200400600800

1000120014001600180020002200

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

Month

Vo

lum

e (M

CM

)

VJK_estimated2005 VJK_predicted2025

VJK_predicted2050 VJK_predicted2095

Wet Dry Wet Dry Wet Dry Wet Dry

Volume (MCM) 3728 996 3583 1290 3605 1459 4074 1500Relative Change (%) -3.89 29.52 -3.30 46.49 9.28 50.60

Volume (MCM) 5057 413 4587 382 4799 484 4924 469Relative Change (%) -9.29 -7.51 -5.10 17.19 -2.63 13.56

2095205020252005

Srinagarind Dam

Vajiralongkorn Dam

Scenarios

Reservoir Operation SimulationData Requirement

Highest water level 180 m MSL

Lowest water level 159 m MSL

Tail water 55.5 m MSL

Highest storage 17,745 MCM

Lowest Storage 10,265 MCM

Surface area 418.8 km2

Annual evaporation 351.1 MCM

Power Plant

Installed capacity 360 MW

Spillway

Type Chute

Crest elevation 171 m MSL

Control gates 3 radial gates

Capacity 2,420 m3/s

Highest water level 155 m MSL

Lowest water level 135 m MSL

Tail water 87 m MSL

Highest storage 8,860 MCM

Lowest Storage 3,012 MCM

Surface area 388 km2

Annual evaporation 210 MCM

Power Plant

Installed capacity 300 MW

Spillway

Type Chute

Crest elevation 146 m MSL

Control gates 2 radial gates

Capacity 3,200 m3/s

Reservoir Characteristics

Srinagarind Reservoir Vajiralongkorn Reservoir

Reservoir Operation SimulationData Requirement

Water Levels of Srinagarind Reservoir

155

160

165

170

175

180

185

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08

Month

Ele

vati

on

(m

. M

SL

)

Water Level Upper Rule Curve Low er Rule Curve Flood Control Curve Minimum Water Level

Existing Rule Curves and Water Level – Srinagarind Reservoir

Reservoir Operation SimulationData Requirement

Existing Rule Curves and Water Level – Vajiralongkorn Reservoir

Water Levels of Vajiralongkorn Reservoir

130

135

140

145

150

155

160

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08

Month

Ele

vati

on

(m

. MS

L)

Water Level Upper Rule Curve Low er Rule Curve Flood Control Curve Minimum Water Level

RESULTS AND DISCUSSIONIrrigation Requirements

Monthly Crop Irrigation Requirement_Upland Crops Only

0

100

200

300

400

500

600

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

Month

Cro

p Ir

rig

atio

n R

equ

irem

ent

(mm

)

Yr2005

Yr2025

Yr2050

Yr2095

Monthly Crop Irrigation Requirement_Paddy Only

0

50

100

150

200

250

300

350

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

Month

Cro

p Ir

rig

atio

n R

equ

irem

ent

(mm

)

Yr2005

Yr2025

Yr2050

Yr2095

Upland Crops

Lowland Paddy

RESULTS AND DISCUSSIONIrrigation Requirements

Monthly Crop Irrigation Requirement_TOTAL

0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

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

Month

Cro

p Ir

rig

atio

n R

equ

irem

ent

(mm

)

Yr2005

Yr2025

Yr2050

Yr2095

2005 2025 2050 2095

Wet Dry Wet Dry Wet Dry Wet Dry

Volume (MCM) 637.48 1597.60 235.97 1739.82 302.94 1721.72 82.94 1814.85

Total 2235.08 1975.78 2024.66 1897.80

Relative change (%) -62.98 8.90 -52.48 7.769 -86.99 13.60

Total Irrigation Requirement

RESULTS AND DISCUSSIONWater Balance Situation

Control Points Available at CP Shortage at CP

  Wet Dry Wet Dry

VJK 7182.29 335.92 0.00 0.00

SNR 5893.38 788.88 0.00 0.00

GMKIP 8339.69 5110.97 30.21 85.89

DIV to Ta-Chin 7067.24 1989.22 0.00 0.00

Salinity Control 6571.18 1596.34 125.28 212.44

Total 155.49 298.33

Control Points Available at CP Shortage at CP

  Wet Dry Wet Dry

VJK 5467.98 385.31 0.00 0.00

SNR 4992.02 1436.55 0.00 0.00

GMKIP 5319.60 5591.04 0.01 23.41

DIV to Ta-Chin 4840.03 2204.15 0.00 0.00

Salinity Control 4282.82 1784.94 105.59 141.02

Total 105.60 164.43

Control Points Available at CP Shortage at CP

  Wet Dry Wet Dry

VJK 6144.27 332.64 0.00 0.00

SNR 5188.08 858.62 0.00 0.00

GMKIP 5447.91 5417.17 0.05 7.68

DIV to Ta-Chin 4828.62 1973.80 0.00 0.00

Salinity Control 4289.92 1520.11 97.20 132.38

Total 97.25 140.06

Control Points Available at CP Shortage at CP

  Wet Dry Wet Dry

VJK 6082.53 581.48 0.00 0.00

SNR 5853.01 1550.27 0.00 0.00

GMKIP 7211.38 5795.71 0.00 52.58

DIV to Ta-Chin 7037.53 2208.76 0.00 0.00

Salinity Control 6478.27 1757.59 12.01 97.47

Total 12.01 150.05

Year 2005 Year 2025

Year 2050 Year 2095

RESULTS AND DISCUSSIONWater Balance Situation

Monthly inflow and release_Sringarind dam

0

200

400

600

800

1000

1200

1400

1600

1800

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

Month

Vo

lum

e (M

CM

)

Inf low

Release

Monthly inflow and release_Vajiralongkorn dam

0

500

1000

1500

2000

2500

3000

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

MonthV

olu

me

(MC

M)

Inflow

Release

Year 2005 • Inflow and release

RESULTS AND DISCUSSIONWater Balance Situation

Water availability, supply and requirement at Irrigation CP_2005

0

200

400

600

800

1000

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

Month

Vo

lum

e (M

CM

)

Supply at CP Requirement at CP

Water availability, supply and requirement at Inter-transfer CP_2005

020406080

100120140160

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

Month

Vo

lum

e (M

CM

)

Supply at CP Requirement at CP

Year 2005 • Water supply and requirement at each control point

Water availability, supply and requirement at salinity control CP_2005

020406080

100120140160

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

Month

Vo

lum

e (M

CM

)

Supply at CP Requirement at CP

RESULTS AND DISCUSSIONHydroelectric Power Production

Power production of VJK

0

1000

2000

3000

4000

5000

6000

7000

8000

January-02 January-03 January-04 January-05 January-06 January-07 January-08

Month

Po

wer

(M

Wh

)

Pow er_act

Pow er_sim

2005_act 2005_sim 2025_sim 2050_sim 2095_simPower (MWh) 17878.38 16931.81 19200.26 28023.38 22335.88Relative Change (%) - - 13.40 65.51 31.92

Total Power Production (MWh)

Vajiralongkorn Reservoir

CONCLUSIONS AND RECOMMENDATIONS

• CONCLUSIONS• Rainfall tends to increase in large amount in wet season, but dry season

rainfall remains more or less similar to the present amount.• With climate change condition, the total irrigation requirements in Greater Mae

Klong Irrigation Project decrease significantly during the wet season and some increment during the dry season

• Large amount of water is available within the basin, but still small shortages occur for the dry season irrigation requirement and at the salinity control point

• RECOMMENDATIONS• Proper water management measures should be proposed to allocate enough

amount of water to each water demand points to avoid shortages• Further studies on estimating the impacts of climate change on inter-basin

transfer and salinity control demands could be done and included in the reservoir operation

• Land use and irrigation area changes could be considered for the future development in the basin

• Operation rule curves could be considered for the changes over the next 100 years

THANK YOU