Temporal quantification and variability of sediment discharge in a semiarid area in northern Algeria

In semiarid areas, the temporal irregularity of flow poses serious problems to the engineers responsible for the evaluation of the sediment discharge into the basin. Further, to decide on a methodology to calculate specific erosion, the flow at two gauging stations in adjacent sub-basins is examined; the water of the two sub-basins is combined a few kilometres downstream in an exploitation dam. Twenty-two years of fine suspended sediment records are studied (1973/74-1994/95). The statistical approach consists of homogenizing the records by means of a statistical regressive model at different temporal scales which allows the evaluation of erosion and enables the productive sediment season to be identified. The monthly approach with the power model is the most significant, explaining, on average, 80% of the total variation. Autumn is particularly productive in sediment, providing an average of more than 50% of the average annual flow of solids.