*2.3.1.1 Topography*

The topographic factor that reveals the slope is one of the first criteria for conditioning runoff. The slope greatly influences the importance of erosion by its gravitational action and provides its erosive energy to water. Thus, the action of erosion increases strongly with slope. Slope steepness acts directly on runoff velocity. When it increases, the kinetic energy of runoff increases and accelerates the transportation of solid objects downwards, increasing the impact of the ablation. According to Refs. [18, 19], the transportation of particles increases exponentially with a percentage inclination of the slope. Topography shows the inclination of relief and the length of the slope. These criteria are very important and directly influence the phenomenon of erosion because it conditions the speed of runoff. In the context of this study, we will retain only the inclination of slope, through its preponderance in the topographic parameter. To this effect, a topographic map of Bafoussam 1c at 1/50,000 provided by the National Institute of Cartography made it possible to digitalize the contour lines. ArcGIS 10.3 made it possible to establish in a precise manner, the interpolation of side points resulting from the contour lines on the slopes map of the basin. These slopes were ordered into five classes (**Table 1**).

## *2.3.1.2 Land use*

The erosion process is closely linked to the mode of land use, which largely contributes either to its aggravation or attenuation. Land use determines the degree of soil protection. This factor is a measure of the relative effectiveness of soil and crop management systems in preventing or reducing soil loss [20]. In terms of soil protection, vegetation is essential because foliage, tree trunks, and roots constitute obstacles that slow down the speed of runoff through the phenomenon of "stem-flow." It also protects against the phenomenon of rain splashing, prolongs the permeability of soils, and reduces the volume of runoff. The degradation of woodlands leads to a profound disturbance in the hydrological regime of the basin and exposes soils, leading to


**Table 1.** *Slope classification.*
