Abhatoo - Centre Nationale de Documentation

In the High Atlas of Marrakech, the watershed areas are submitted to important and frequent floods, associated with landslide and rockslide. Morphological and lithological characteristics of the basins watershed have a clear influence on the rising waters strength and the hydrogram’s shape. The products of erosion accumulated in the upstream part as gravity accumulation and fans are remobilised during high floods when the discharges increase. This situation make flows muddy and torrential. The consequences of these natural risks can be grave in term of damage and cost. In the Ourika valleys, we are confronted to the amplification and repetition of this process owing to its deepness and narrowness. Furthermore, the degradation of environment speeds up because of the development of tourist activities. All these conclusions suggest the management of these suddenly beating of flows.