Assessing Water Erosion Vulnerability in the Lower Ziz Watershed: Integrating PAP/RAC methodology with Remote Sensing and GIS

Abstract

Degradation presents a significant challenge, particularly exacerbated by current climate change. Our study focuses on the Lower Ziz watershed, located in southeastern Morocco, which is characterized by a semi-desert climate and is at high risk of land degradation due to water and wind erosion. Natural factors such as precipitation intensity and frequency, slope inclinations, low vegetation cover density, and soil characteristics, combined with anthropogenic activities, contribute to increasing the erosion risk within this watershed. The use of unsustainable agricultural practices has also contributed to this growing vulnerability. To investigate this phenomenon, we adopted the PAP/CAR method, a qualitative approach for mapping and assessing vulnerability to water erosion in the watershed. This method integrates essential physical data such as topography, lithology, soil types, and vegetation cover, facilitating a comprehensive analysis of erosion risk. Through the use of remote sensing tools and geographic information systems (GIS), we have generated detailed thematic maps, streamlined the mapping process, and improved data management. The findings of this research provide valuable insights for sustainable land and natural resource management in the Lower Ziz watershed and can aid in the formulation of prevention and mitigation strategies for water erosion in similar contexts globally. Our predictive mapping approach indicates that 37.34% of the watershed exhibits low to very low susceptibility to water erosion, while 55.96% experiences moderate erosion, with the remaining 6.7% being highly erodible. Additionally, our descriptive analysis highlights the prevalence of gully and surface gullying erosion, encompassing 49.32% of the area, as well as deep gully erosion, affecting 41.89%.”