Assessment of Water Erosion by Integrating RUSLE Model, GIS and Remote Sensing – Case of Tamdrost Watershed (Morocco)

Abstract

Water erosion caused by rainfall and runoff, in the Morocco is the main threat of fertile agricultural soil losses causing important silting-up of dams. Most watersheds are characterized by excessive values of Soil Specific Degradation (Average annual soil loss per year and per km2), exceeding in many regions 2000 T/km2/year. The main objective of this study is to investigate this phenomenon in the Tamdrost watershed located in northwest-ern Morocco. The methodology is based on integrating water erosion RUSLE model to Geographic Information System and satellite image processing. The aim of the study is to develop digital mapping for the main factors involved in the erosion processes as well as the variation of the average annual quantity of soil losses. The results outcome are: (i) the average value of the specific degradation is about 80 (T/ha/year), reaching a maximum value of 800 T/ha/year and a minimum value of 3 T/ha/year; (ii) The main factors that control water erosion by order of importance are successively: R, LS, K, and C factors. Finally, different maps representing erosion and the main factors involved, are be very helpful for decision makers to better assess this phenomenon and to implement anti-erosion measures in the threatened areas to support and control the water erosion.