干旱区生态环境知识资源中心

Water supply for the arid irrigated plains in Morocco depends largely on the upper mountainous basins where significant amounts of precipitation fall as snow. In the Oum Er-Rbia River Basin (OER), snow covers the highest elevations from November to April. Despite the importance of this component in the hydrological cycle, snowmelt contribution to streamflow is still poorly understood and no monitoring stations exist in this zone. Therefore, studying the spatiotemporal change of snow cover through satellite observations to investigate its influence on the hydrological response of this scarce region is thus required to better manage water resources. This chapter explores basic characteristics of snow cover area (SCA) in the upstream area of the OER River (Tillouguite sub-basin) using MODIS daily snow cover products (MOD10A1). Correspondence between streamflow, accumulated air temperature and SCA changes during the winter and spring periods was examined from 2001 to 2009 at a weekly time step. The result shows an inverse linear relation between the maximum SCA and the mean normalized stream flow values, and a significant relation between the relative streamflow and cumulated temperature, especially during spring melt season depending on the length of the melt period. These primary results could be used to develop simplified predictable models for spring discharge in ungauged watershed using remote sensing and accumulated air temperature.