Assessing soil erosion vulnerability through geospatial morphometric analysis in the Oued Amter Basin (Northwest Morocco)

Sustainable development is threatened by soil erosion. Since it takes over 300 years for a centimeter of soil to form, preventing soil erosion is essential to safeguarding priceless resources. In any hydrological analysis, morphometric analysis is a relevant scientific method that is essential to the development and management of drainage basins. The main objectives of this study were (i) to analyze the morphometric parameters of the Oued Amter Basin using geographic information systems (GIS) and remote sensing (RS) (geospatial tools) and (ii) to prioritize sub-basins and identify the major morphometric parameters that influence soil erosion in the Oued Amter Basin. Morphometric analysis of the Oued Amter Basin (300 km²) was performed to prioritize sub-basins based on their susceptibility to erosion by water using geospatial tools (remote-sensing-based data and a GIS). The linear, relief, and shape morphometric parameters of the drainage network were calculated using data from the Advanced Land Observing Satellite (ALOS) phased-array L-type synthetic-aperture radar (PALSAR) digital elevation model (DEM) with a spatial resolution of 12.5 m. These parameters revealed the network’s texture, morpho-tectonics, geometry, and relief characteristics (including stream length (Lu) and mean stream length (Lsm), stream length ratio (RL), bifurcation ratio (Rb), average bifurcation ratio (RBM), drainage density (Dd), drainage texture (T), flow frequency (Fs), elongation rate (Re), circularity ratio (Rc), form factor (Ff), relief, and relief ratio). Using the array of compound (Cp) values that were computed, we set the priority ranks and divided the sub-watershed into four priority-rank groups: (i) low, which represents 5% of the basin surface; (ii) moderate, which represents 30%; (iii) high, which represents 35%; and (iv) extremely high, which represents 30% of the basin surface. The results show that this classification is valuable for prioritizing and planning interventions focused on addressing soil erosion and mitigating natural hazard risks within the watershed. The method tested here has been shown to be an effective tool to improve sustainable soil management.