Mapping of Soil Water Erosion and Prioritization of Conservation Measures in the Noun Watershed (West Cameroon Highlands)

Abstract

Soil erosion is a natural hazard that is exacerbated by human activities in the West Cameroon highlands. However, there is little information on the spatialization of this phenomenon at the territorial scale. This study is based on the use of the Universal Soil Loss Equation (USLE) model and open access data to map areas at risk of erosion and prioritize areas for soil conservation in the Noun watershed. According to the results, 22.61% of the territory is characterized by a low risk of erosion while 77.39% faces a risk of soil loss higher than the tolerable limit of 11 t/ha/year in the context of tropical and mountainous landscapes. This risk is accentuated by the loss of vegetation cover in favor of the expansion of urban and agricultural areas. The low level of sensitivity to erosion is found in the lowlands, while the areas located in the plateaus present a high level of sensitivity due to their rugged terrain and high rainfall. Statistical analysis of landslide frequency ratios shows a relationship between landslide occurrence and erosion intensity zones. Modeling of soil loss as a function of different soil protection methods shows that the strip-grass approach and terracing are the most appropriate for reducing erosion risk in this area. These methods can be combined with afforestation efforts for effective soil protection.