Suspended sedimentary dynamics under Mediterranean semi-arid environment of Wadi El Maleh watershed, Algeria

Soil degradation due to erosion by water is a serious environmental problem for the integrated management of basins, affecting the soil and water resources in Algerian region. Pluvial flood has been increasingly understood as a major threat that has presented a significant risk for many watersheds worldwide, estimation of runoff and sediment yield is primarily required for watershed development planning involving soil and water conservation measures, considering runoff is responsible for sediment detachment and their transport during the erosion processes. In this context, the phenomenon reaches spectacular values in many Algerian watersheds; in this case, it is very severe in flood period, many models have been developed and their application has been spread. In this study, water flow discharge and suspended sediment concentration have been modelled using sediment rating curve approach, this model is the large discussed model; it is the best significant equation for the majority of Algerian basins, this equation which has a power law form (i.e. C = aQ b , where a and b are fitted parameters), explains, more than 72% for the whole floods observed during 17 years in Wadi El Maleh watershed, the flood contribution in annual suspended yield is variable; it can reach more than 92%, which is the case of flood; January 19, 1985, while, at inter-annual scale, the percentage is 24% and 43% in total water and suspended sediment yields, respectively; for all studied floods, a good logarithmic correlation between sediment rating curve parameters is observed, this outcome can help to extrapolate this model to other events.