e area of Nylon represents a sensible and vulnerable environment where water erosion is the cause of many soil losses contributing to the production and movement of sediments from the upstream to the lowest depths. e high level of rainfall in this town, soil texture (sand-clay-silt), and the anarchic occupation of the area play a part in the important deterioration of the bare ground on the upstream of the catchment area. is causes with time an instability of structures and living places which can lead to their progressive disappearance. In order to assess the quantities of displaced sediments, the studies on the quantification of soil moved annually by water erosion are carried out. A direct method is used consisting in using a minisimulator of rain (NEME) in order to understand the phenomena involved and assess the quantity of sediments which can be moved. It helps in assessing erosion caused by the rain and extrapolating results over the catchment area of the chosen field of study. USLE relation has permit to make an extrapolation of the quantity of soil affected, and the result shows that the average potential of loss of soil is 153.57 t/ha/annum.

Our study is being carried out in the Wouri Estuary more precisely in the Nylon area, Douala. This area is influenced by abundant rainfall which promotes the phenomenon of rain erosion. This erosion contributes to the degradation of structures and soils. To better understand and predict this phenomenon of rainfall erosion, we set out to establish a mathematical model that takes into account precipitation and topography. To this end, the data collected in the field and in the laboratory made it possible. First, we graphically modeled the variation of the potential as a function of the intensity of rainfall and the slope of the ground. Next, we identified a mathematical model from cubic spline surface interpolation. Finally, we obtained the mathematical model which makes it possible to evaluate and predict the erosion potential. The results obtained allowed to have an erosion potential of 153.67 t/ha/year with field data and 153.94 t/ha/year with laboratory data. We compared the results obtained with those existing in the literature on the same study site. This comparison made it possible to validate the established mathematical model. This mathematical model is a decision support tool and can predict problems related to water, erosion and the environment.