Watershed Modeling

The unique dataset generated by the project, which to date includes 5-year long runoff, sediment yield, and nutrient loss series, along with socio-economic baseline data collected at household level, is being used to develop and calibrate hydrological and bio-economic models. Global climate change scenarios are also being downscaled and analyzed. These models will be used to analyze system dynamics, productivity and constraints at the watershed scale, and to simulate the hydrological and socio-economic impacts determined by varying climate and land use scenarios. The models’ results will show how different spatial arrangement of the soil conservation measures and of the improved management options may generate different hydrological and economic impacts. This will indicate how a better integrated watershed management can be achieved, and will create a sound basis to draft recommendations for up-scaling.

SWAT Model and Simulations

Researchers combined the field data with digital data using the SWAT model. A preliminary version of the calibrated model was used to simulate surface runoff and sediment yield under two different land use scenarios.

  • Scenario 1: Slopes greater than 50% in the northern part of the watershed are forested, and soil and water conservation are applied to the rest of the watershed.
  • Scenario 2: A small area in the northern part of the watershed is forested and soil and water conservation are applied to the rest of the watershed, including the outlet of the watershed.

The simulations showed that soil and water conservation and afforestation of areas with slopes greater than 50% could reduce sediment yield by 79-86% compared to the present situation.