Water Allocation Scenarios to explore Green Water Credits opportunities Peter Droogers, SEI Holger Hoff, SEI

Water Evaluation & Planning System  SWAT Supply analysis, basin scale Supply analysis, basin scale  WOFOST Detailed crop analysis Detailed crop analysis  WEAP Demand size allocation and benefits Demand size allocation and benefits

 Possible questions to be answered How is blue water currently allocated between different uses? How is blue water currently allocated between different uses? What unmet demands can be expected if current trends are projected into the future? What unmet demands can be expected if current trends are projected into the future? What are alternative allocations to maximize benefits? What are alternative allocations to maximize benefits?

 Possible alternatives How should reservoirs be operated to maximize benefits? How should reservoirs be operated to maximize benefits? What would be the downstream effects of additional reservoirs (Mutonga-Grand Falls) ? What would be the downstream effects of additional reservoirs (Mutonga-Grand Falls) ? What is the effect of erosion control on reservoir siltation and hydropower generation? What is the effect of erosion control on reservoir siltation and hydropower generation?

What is WEAP  Old: Water Evaluation and Allocation Program  Water Evaluation And Planning system

Data Requirements  Water supply, provided by SWAT model Time series data of riverflows for Tana and tributariesTime series data of riverflows for Tana and tributaries River network (connectivity)River network (connectivity) Reservoir and hydropower generationReservoir and hydropower generation  Water demand, to be provided by national partners Time series data of sectoral demandsTime series data of sectoral demands Trends in population, economic development etcTrends in population, economic development etc  Complementary data householdshouseholds poverty rates in the upstream areaspoverty rates in the upstream areas

Data Requirements (continued)  Sectoral water demands Municipal, hydropower and other demand Municipal, hydropower and other demand Aggregated by sectorAggregated by sector Disaggregated by population (e.g., use/capita, use/socio-economic group)Disaggregated by population (e.g., use/capita, use/socio-economic group) Agricultural demands Agricultural demands Aggregated by area (# hectares, annual water- use/hectare)Aggregated by area (# hectares, annual water- use/hectare) Disaggregated by crop water requirementsDisaggregated by crop water requirements Ecosystem demands (in-stream flow requirements) Ecosystem demands (in-stream flow requirements)

SWAT: Supply site

Conclusion  Models: SWAT SWAT Supply (generation of green water credits)Supply (generation of green water credits) WEAP WEAP Demand (benefits from green water credits)Demand (benefits from green water credits) Explore scenarios Explore scenarios Proof of green water concept Proof of green water concept  SWAT, WEAP only support tools: Socio-economic analysis Socio-economic analysis Policy support Policy support

Thank You