Abstract: “Soil loss from one area is normally transferred to and deposited in another by flow processes. The direction of flow, specifically overland flow or runoff, can be determined by finding the direction of steepest descent from each point on the terrain surface. This study aims to determine the flow direction using GIS or, in the case of a raster, digital elevation model (DEM), from each cell in the DEM. The soil flow directions are determined to identify areas from which the soil erodes and where it deposits. In areas such as tropical forest, trees located on the area where the soil erodes should not be harvest as this will accelerate erosion.”

Keywords: soil erosion, flow direction, Geographic Information System (GIS), programming, tropical forest