Spatial Modeling of Water Erosion and Sediment Transport Using Geographic Information Systems (GIS) (Case of Boughezoul Watershed)

Abstract

The present study employs an integrated spatial approach, combining Geographic Information Systems (GIS) and the Revised Universal Soil Loss Equation (RUSLE) to assess water erosion and sediment transport in the Boughezoul watershed, located in semi-arid Algeria. The RUSLE factors (R, K, LS, C, and P) were mapped using a Digital Elevation Model (DEM), rainfall data, land cover information (ESA WorldCover), and soil data (FAODSMW).The

Sediment Delivery Ratio (SDR) was estimated using empirical methods to address RUSLE’s limitations in modeling sediment transport. Results indicate that approximately 17% of the mobilized sediments reach the watershed outlet. In addition, several morphometric and hydrological indices (SPI, TRI, CTI, SDI) were calculated to enhance the spatial characterization of erosive processes.Thematic layers were integrated through raster algebra to generate a composite erosion risk map. This final map highlights a marked variability in soil loss, ranging from 0.213 to over 186 t/ha/year. It illustrates a higher concentration of erosion risk on agricultural slopes with steep gradients and sparse vegetation cover. The map helps identify the most vulnerable zones, which may serve as priority areas for the implementation of soil conservation measures. It serves as a valuable decision-support tool for sustainable soil management in semi-arid environments. I