Évolution de la concentration des sédiments en suspension et du débit liquide durant les crues et le phénomène d’Hystérésis dans le sous bassin de l’Oued Djdiouia (Nord-ouest algérien)

Abstract

The sub-basin of the Djdiouia wadi, tributary of the left bank of the Cheliff near Oued Rhiou north of Relizane, covers 835 km². This basin is quite representative of many basins of the semi-arid northern fringe of Algeria. In this paper, we are interested in the analysis of the discharge/concentration relationship at the scale of individualized floods, which is much more oriented to the graphs that give the framework presented in the chronological order C and Q. Thus, the analysis of the evolution of the concentrations of the suspensions according to the discharge during the floods of the sub-basin of wadi Djdiouia showed three models of curves (hourly loop, anti-clockwise loop and a form of eight). The models of classes III and V are the most frequent, reflecting a high availability of sediments after a dry season when the soil is particularly weakened and the appearance of a peak discharge before the maximum concentration, reflects a net deposition of sediments in the stream. We cannot neglect the Class II model, which is also necessary. It reflects a supply of sediment even during the flood.