Africa Soil Information Service (AfSIS): Specific Catchment Area (SCA)

The Africa Soil Information Service (AfSIS): Specific Catchment Area (SCA) is a 90m raster dataset showing local flow accumulation and flow direction using the formula SCA = A/I, where A is unit contributing area of land upslope of a length of contour I. The specific catchment area contributing to flow at any given location can be used to determine relative saturation and water runoff and, together with other topographic factors, can be used to model erosion and landslides.

The digital elevation model used to construct this dataset is AfHydSRTM, which is based on the CGIAR-SRTM 90m Version 4. The dataset was produced at the World Agroforestry Centre (ICRAF) in Nairobi, Kenya and is distributed by the Africa Soil Information Service. The specific catchment area is a useful parameter for modeling of runoff, soil erosion and sediment yield.The images and data are available from the Africa Soil Information Service (AfSIS) in Geographic Tagged Image File Format (GeoTIFF) format via download at africasoils.net/.