Soil erosion is a complex phenomenon, which particularly influences water and soil potentials. In the mountainous areas, water erosion phenomenon is accentuated by steep slopes and the degradation of vegetation cover. soil erosion is a worldwide phenomenon threatening the social, environmental and the economic life. In Morocco, fluvial erosion is one of the issues that affects the national territory. The location of Morocco, in the south of Mediterranean region provides remarkable climatic and ecological diversity. Located in the Moroccan High Atlas, El Abid basin belongs to a semi-arid climate. It is characterized by steep slopes and abundant precipitation which gives mountain flows a torrential characteristic. The discharge can reach very important values. Long term hydrological records for El Abid river demonstrate the annual and seasonal variability in discharge with winter and spring periods typically representing 87% of the flow. Soils are increasingly degraded and sediments from erosion contribute to the siltation of Bin Ouidane dam. This siltation is the result of deposits of soil erosion. During flood periods this dam is silted by the sediment transport. This article aims to quantify the rate of fluvial erosion in the upstream section of the Bin El Ouidane dam. Then, to understand the process of river dynamics and its impact on silting issue, through the application of an approach technique based on the realization of several cross profiles, and with a main objective being to compare the results of the river dynamics of the two campaigns during 2016 and 2017. In addition, the measurements taken were supplemented by qualitative observations, particularly during the baseflow of the river, the incision of the bed (or stream), the regressive erosion of the banks, the apparent nature of the substrate, and certain anthropogenic actions.

Dynamic of landscapes related to climate change and modification of land uses are the crucial elements that controlling hydrological responses within basins. Besides, in the Mediterranean areas, most of the authors indicate the role played by dynamic and change of land cover, and climate characteristics for determining and generating the hydrological processes and the resulting alterations of the surface at spatial and temporal scales and subsurface flow patterns. The purpose of this article is to compare the dynamic of both rating curves in order to extract the discharge for understanding the response and hydrological behaviour of the two selected headwaters (i.e., area = Kousser 311.09 km2 and Annergui 69.81 km2), which are situated within middle part of high Atlas Mountains (Morocco) at central part of Assif Melloul River basin. The dynamic of rainfall, and land cover dynamics were been considered in order to extract their observed changes in discharge at the studied headwaters. Besides, the estimation of the discharge in the outlet of both catchments is based on monitoring of the water level by limnimeter. The value of the obtained discharge is extracted by the rating curve method. The obtained results show a clear seasonality of the Assif Melloul basin, which is characterized by variability of the hydrological regime with high inter-annual in space and time. The maximum water level-discharge value at the two catchments is recorded during wet periods (19 m3/s-1 at Annergui and 1m3/s-1 at Kousser catchments), while the minimum level is registered during dry seasons (0.46 m3/s1 and 0.21 m3/s-1). Consequently, this presented work will be a good investigation for managers to decrease the future impacts and risks related to flash flood events at catchment scale.