The potential benefits ofGreen Water Credits

Part 2:Quantifying profits for

downstream water usersPeter Droogers

Wilco TerinkJohannes Hunink

Sjef KauffmanGodert van Lynden

WHAT to quantify?

• Supply Biophysicial assessment

• Supply vs. Demand Cost-benefit analysis

OVERALL BENEFIT-COST ANALYSIS

Recall: changes in supply

Required: an integrating tool

• Impact of changes in water-soil dynamics on:– upstream

• rainfed improved production– downstream

• hydropower• domestic water supply• irrigation

• Benefit-cost analysis

• Integrations tool: WEAP

WEAP Tool

WEAP: Validation

Masinga Inflow

Masinga Outflow

Kamburu Outflow

Gitaru Inflow

Kindaruma Outflow

Kiambere Outflow

Changes reservoir storage

00_Base 01_Bench 02_ConsTill 03_ContTill 04_FanyaJuu 05_GrassStrips 06_MicroCatchments 07_Mulching 08_Rangelands 09_Ridging 10_Riverine 11_TrashLines

Reservoir Storage VolumeAll Reservoirs (9), All months (12)

Jan2005

Mar2005

May2005

Jul2005

Sep2005

Nov2005

Jan2006

Mar2006

May2006

Jul2006

Sep2006

Nov2006

Milli

on C

ubic

Met

er

60

55

50

45

40

35

30

25

20

15

10

5

0

Results: Reduction in water shortage

00_Base 01_Bench 02_ConsTill 03_ContTill 04_FanyaJuu 05_GrassStrips 06_MicroCatchments 07_Mulching 08_Rangelands 09_Ridging 10_Riverine 11_TrashLines

Unmet DemandAll Demand Sites (13), All months (12)

2005

Milli

on C

ubic

Met

er

0.0-0.5-1.0-1.5-2.0-2.5-3.0-3.5-4.0

-4.5-5.0-5.5-6.0-6.5-7.0

Results: Increase in hydropower

00_Base 01_Bench 02_ConsTill 03_ContTill 04_FanyaJuu 05_GrassStrips 06_MicroCatchments 07_Mulching 08_Rangelands 09_Ridging 10_Riverine 11_TrashLines

Hydropow er GenerationAll Reservoirs (9), All months (12)

2005

Thou

sand

Gig

ajou

le

180

160

140

120

100

80

60

40

20

0

Results: Increase in Benefits

Results: Benefit-Cost Analysis

• 20% of area ~ 100,000 smallholders

Benefits Costs mUS$/y ha 01_Bench 9.9 92,865 02_ConsTill 1.0 52,766 03_ContTill 4.9 52,766 04_FanyaJuu 9.0 92,865 05_GrassStrips 5.3 92,865 06_MicroCatch 1.6 1,000 07_Mulching 5.1 92,865 08_Rangelands 0.8 136,916 09_Ridging 8.9 52,766 10_Riverine 2.0 10,000 11_TrashLines 3.4 92,865

Costs Construction Maintenance

ha US$/ha US$/ha /y mUS$/y 92,865 100 20 2.8 52,766 0 0 0.0 52,766 0 0 0.0 92,865 200 20 3.7 92,865 50 20 2.3 1,000 500 20 0.1

92,865 0 0 0.0 136,916 50 0 0.7 52,766 100 20 1.6 10,000 100 20 0.3 92,865 50 20 2.3

B/C

mUS$/y mUS$ 2.8 7.1 0.0 1.0 0.0 4.9 3.7 5.3 2.3 3.0 0.1 1.5 0.0 5.1 0.7 0.1 1.6 7.3 0.3 1.7 2.3 1.1

DISCUSSIONS, CONCLUSIONS

Wrapping up

• GWC beneficial for:– upstream– downstream

• Analysis tools:– SWAT: (upstream) supply– WEAP: (downstream) demand

• Steps– Understand current situation– Explore options

• GWC– Biophysical component– Socio-economics– Institutional– Financial

Discussion / conclusions

• Smaller focus area– Current study: 1.8 million ha total; 0.5 million ha rainfed– Target areas– C/B analysis

• Definition of GWC options– Practical WOCAT expertise in implementation phase

• Monitoring network– Update according to recently finished survey– Indicators to evaluate effectiveness of implementation

THANK YOU