*3.2.1.2 Consideration of slope gradient nature*

To understand the impact of topography, the map of slope gradient of Gishwati watershed using ArcGIS spatial analysis tools has been generated from the Digital Elevation Model (DEM −30 m resolution), accessed from the United States Geological Survey (USGS) database (http://earthexplorer.usgs.gov/). Digital representation topography (DTM) generated from DEM helped to calculate five slope classes (0–6, 6–16, 16–40, 40–60 and > 60%) (**Figure 4**).

Outputs of the slope map generated provided distribution of slope classes as follow: 50% of the Gishwati area (3290 ha) are located within 16–40%, 23% (1491 ha) within 40–60%, 13% (895 ha) within 6–16%, 10% (659 ha) within 0–6%, and finally 4% (279 ha) is above 60%. However, the forms of slope are so complex so that the slope criterion was not easy for defining recommendation zones [17]. Thus, scientists managed to agree on the approach for protecting this complex biophysical environment. RUSLE model helped to develop erosion risk assessment whereby slope factor contributed more (**Figure 4**).
