Erosion susceptibility assessment through morphometric analysis and sub-watershed prioritization in the nyong watershed, Southern Cameroon

The Nyong River sub-watershed in the southern Cameroon plateau has been prioritized for urgent conservation action due to its erodibility, using the morphometric and hydrological criteria. Six sub -watershed were delimited from the Shuttle Radar Topography Mission (SRTM) data in a geographic information system environment. The Sub-Watershed Prioritization Tool (SWPT) was used to analyze the weighted sum (WSA) parameters of these sub-watersheds. Field investigations, including river water sampling, were carried out from January to August 2024 to estimate the suspended solids (SS) rate in each sub-catchment. Key morphometric parameters, such as compactness index, drainage density and form factor, were calculated and weighed. Based on the results, particularly the CPV, the Ayos, Mbalmayo and Olama sub-watersheds with CPV ranging between − 853 to -3.6 were classed as high priority and therefore most erodible. On the contrary, Abong-Mbang, Akonolinga, and Pont So’o sub-catchments with CPV of -275.27, -311.36 and − 33.86, respectively, showed moderate vulnerability. The CPV results were generally coherent with suspended solid content from river water samples in the area. The suspended solids content (in mg/l) obtained from river water samples was as follows in the sub-catchments: Ayos (18.12); Mbalmayo (14.24); So’o (10.1); Olama (6.24); Abong-Mbang (6.17), and Akonolinga (2.81). Except for Pont Soo, the sub-basin prioritization CPV ranking ties closely with the SS values. This study provides decision-makers with strategic information for land and water resource management in tropical ecosystems.