Erosion and solid transport processes in the Isser Wadi watershed, Algeria

The aim of this study was to find a significant relationship between the concentration of suspended sediments and the instantaneous liquid flow in the Isser Wadi watershed, northern Algeria. The study was performed using a dataset containing 5838 values on water height, instantaneous liquid flow (Q(l); in m(3)/s) and concentration of suspended sediments (C; in g/l) during the period 1978-2002. The results showed a slight correlation between the parameters C and Q(l) even after combining the series by class and determining the median concentration and the median liquid flow. Analysis of the evolution of sediment concentration in the stream and the quantification of sediment fluxes showed that the sediment supply occurs mainly during floods. Three periods of active erosion were identified, with one period of intense erosion occurring in the winter and two periods of lesser erosion occurring in the spring and autumn, respectively. A very significant relationship (Q(s) = 1.24 x Ql1.34, R = 0.72) was found between solid and liquid flows in suspension (Q(s) and Q(l), respectively). This relationship was used to estimate the solid transport in this basin. This case study provides a qualitative approach to solid transport across the catchment of Isser Wadi that could support reliable database in a semi-arid environment.