Estimation of suspended sediment transport in the Kebir drainage basin, Algeria

摘要

Sediment load and sediment concentration are highly important variables that may play a key role in environment quality assessment and help to evaluate the extent of potential adverse impacts. This paper introduces a methodology to predict sediment loads in the Kebir drainage basin (681 km~2). The methodology is developed by a conventional sediment rating curve and a multiple regression model. The former method is investigated with the mean discharge classes derived from the recorded instantaneous suspended sediment concentrations and water discharges for the Kebir basin, prior to the Mexa reservoir construction. The latter is based on rock type erodibility, mean annual runoff and basin area variables, and which is applied for the ungauged Mexa reservoir basin located upstream of the Kebir gauging station (651 km~2). The mean annual suspended sediment yield of both Kebir drainage basin and Mexa reservoir basin conducted during the 24 years (1975/1976-1998/1999) and the 9 years (1999/2000 -2007/2008) are respectively 895 T km~2 year-1 and 572 T km~2 year-1. Despite the decline in sediment load during the reservoir period due mainly to disturbance in climatic regime, the basin is suffering severe soil loss, and currently 0.42% y-1 in loss of storage in the reservoir due to sedimentation has been evaluated. The high amount of sediment produced from the study drainage basin is a function of climatic and several physical factors including the high proportion of argillaceous materials and the amount of bare soil exposed.