
Scope of SWAT modeling to support catchment area management in Nepal
The purpose of the proposed Soil and Water Assessment Tool (SWAT) modeling in Nepal will be to provide baseline hydrologic information on daily flow and sediment loads in selected watersheds, and results from selected land management scenarios. The International Water Management Institute (IWMI) project team will conduct rigorous sensitivity analyses, calibration, and where data allows, validation of the SWAT model in the selected watersheds. Scenarios assessment will be performed with the calibrated model to compare runoff and sediment under baseline conditions to alternative land cover configurations that allow assessment of the marginal contribution of natural land covers to avoided erosion and sediment delivery to streams. The number of scenarios required will depend on the further elaboration of the approach, but between 3 and 6 scenarios per study watershed will probably be sufficient. Model outputs (daily flow, sediment loads) for the selected watersheds and delineated sub-watersheds will be shared with the broader team and included in a final modeling report to World Bank. The team will work closely with broader NatCap/World Bank team to ensure that SWAT outputs are in the appropriate scale, resolution and format for use with the RIOS models, and that scenarios developed using the RIOS model are appropriately represented in the SWAT model to allow for assessment of the marginal contribution of land covers to avoided erosion and sedimentation. A final report will also detail the results of model calibration, validation, and summarize the results.