resource allocation and optimisation model raom october 2003

Resource allocation and optimisation model

Resource allocation and optimisation model

RAOMOctober 2003

2

Resource allocation and optimisationResource allocation and optimisation

What is the best way to allocate water in the LMB, to meet agreed planning objectives?

Assessment criteria– define what is “best” (optimal)

in economic, social and environmental terms

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Many possible scenarios– combinations of external conditions and

interventions

RAOM is rapid appraisal to narrow down options– identify feasible and “optimal” combinations

DSF provides detailed analysis of most promising options

RAOM is NOT a substitute for DSF

Scenario-based planningScenario-based planning

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Resource Allocation and Optimisation Model

Resource Allocation and Optimisation Model

Simplified hydrological model plus optimisation tool

Model being developed for BDP by Halcrow– spreadsheet based (Excel plus “What’s Best”®)

– fast and easy to run

– “lumped” model – NOT DETAILED

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RAOMRAOM 10 sub-basins (BDP sub-areas)

Monthly time-step

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OptimsationOptimsation

Values can be assigned to each water use Can optimise for different values

– economic return

– environmental values

– combination

Optimiser allows us to identify the “best” mix of uses to meet agreed objectives– within identified constraints

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Storage

Irrigation

Water supply

Hydropower

Flow from catchment

INFLOW

OUTFLOW

$

In-stream use

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Storage

Irrigation

Water supply

Hydropower

Flow from catchment

INFLOW

OUTFLOW

Z

$Zenv

Zfish

Zflood

In-stream use

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1

2

3

10

....

Optimisation

$ Economic

Z Environment

$+Z Combined

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Data required - hydrologyData required - hydrology

Derived from DSF– Inflow from upper basin

– Inflows from each sub-area

Model runs for single year – June – May

Representative “wet”, “medium”, “dry” years

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0

20000

40000

60000

80000

100000

120000

140000

Jan-

91

Jul-9

1

Jan-

92

Jul-9

2

Jan-

93

Jul-9

3

Jan-

94

Jul-9

4

Jan-

95

Jul-9

5

Jan-

96

Jul-9

6

Jan-

97

Jul-9

7

Jan-

98

Jul-9

8

Jan-

99

Jul-9

9

Jan-

00

Jul-0

0

Means: Chiang Khan: Flow

Means: Chiang Saen: Flow

Means: Kho Khel: Flow

Means: Kratie: Flow

Means: Luang Prabang: Flow

Means: Mukdahan: Flow

Means: Neakluong: Flow

Means: Pak Mun: Flow

Means: Pakse: Flow

Means: Phnom Penh (Bassac): Flow

Means: Phnom Penh (Mekong): Flow

Means: Stung Treng: Flow

1999medium

1998low

2000high

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Data required - damsData required - dams

Size of reservoirsPurpose

– Irrigation, hydropower, mixed

Water release pattern– from hydrological records, or calculated

Value of power production

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Data required - irrigationData required - irrigation

Areas irrigated– Source of water (unregulated

catchment flow, mainstream river, irrigation or hydropower reservoir)

Crop water requirements (by month)Crop value

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Basin 4 km2crop 1

crop 2

crop 3

crop 4

Value ($/km2) 100 220 300 300

Unregulated 1000

Regulated Irrigation 200

Hydropower etc 20

Main river reach 50

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0.00

0.05

0.10

0.15

0.20

0.25

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

Crop 1

Crop 2

Crop 3

Crop 4

Crop water requirements

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Basin 4 km2crop 1

crop 2

crop 3

crop 4

Value ($/km2) 100 220 300 300

Unregulated 1000 250 400

Regulated Irrigation 200 200

Hydropower etc 20 20

Main river reach 50 50

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0

20000

40000

60000

80000

100000

120000

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

1998/9

1999/2000

2000/01

Baseline

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Scenario 1: increased irrigationScenario 1: increased irrigation

Sub-area Baseline Scenario 1

Area Irrigated km2

1 100 400

2 2020 2222

3 5100 5600

4 1270 2750

5 15000 16500

6 400 900

7 1500 3500

8 200 2150

25590 34022

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Dry year 1998

Medium year 1999

Wet year2000

June 1% 0% 0%

July 0% 0% 0%

August 0% 0% 0%

September 0% 0% 0%

October 0% 0% 0%

November 0% 0% 0%

December 3% 3% 3%

January 5% 5% 5%

February 10% 10% 10%

March 11% 11% 10%

April 8% 8% 10%

May 1% 1% 1%

Flow decrease at Kratie with increased irrigation

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RAOMRAOM

Rough scenario analysis Allows user to identify resource constraints

eg– minimum or maximum allocations for irrigation

– minimum flows for environment

Comparison of values for different uses

Not enough water

70

Not enough land

Total flow = 100I + E = 100

Irrigation limited by land availabilityI < 70

100

100

Minimum flows for environmentE > 20

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Ba

se fl

ow

sWater forIrrigation

I

Water for environmental flows

E

But which allocation is optimal?

100

100

70

20

Water forIrrigation

I


E

INFEASIBLE

FEASIBLE

AssumeV = 2*I + E

100

100

70

20

Water forIrrigation

I


E

V=100

V=170

V=160

“Optimum”I=70, E=30V = 170

Objective function

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Data inputsData inputs

Hydrological data from WUP DSF– inflows– catchment flows– storage for irrigation, hydropower– extraction for irrigation, water supply– outflows

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Hydrological data from WUP DSFEconomic data compiled by BDP

– crop types and gross margins

– value of hydropower production

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Hydrological data from WUP DSFEconomic data compiled by BDPBDP and IBFMP will assess “values”

of different uses– input from EP, FP, FMP, AIFP, NP

– need to develop links between river flows and environment (flood extent, wetland quality, fish productivity etc)

environmental indices

– costs / value of environmental flows and floods

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Hydrological data from WUP DSFEconomic data compiled by BDPBDP and IBFMP will assess “values”

of different uses

Hydrological modeling in RAOM is consistent with the WUP Basin Models,

but much simplified

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WUP DSFWUP DSF

DSF analyses impacts of particular scenarios

– detailed hydrological model

– environmental (and social) impacts

– detailed spatial and temporal analysis

– complex

– time-consuming

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ISIS (below Kratie)> 800 sub-basinsHourly time-step

SWAT 172 sub-basinsDaily time-step

DSF

resource allocation and optimisation model raom october 2003

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