The Dynamics of Suspended Particulate Matter in the Oued Nachef (Tafna Basin, Algeria): Typology of Flood Events and Contribution to Sediment Transport

Abstract

This article focuses on the study of sediment transport during flood events in the Oued Nachef watershed that feeds the Mefrouche dam. To understand the sediment dynamics in this watershed, ANRH data on instantaneous water discharges and the respective concentrations of suspended particulate matter were used. This enabled the selection of some of the largest flood events over a 24-year period in order to establish the log-log relationships between sediment load (concentration and flux) and water discharge. However, the discharge-concentration relationships revealed hysteresis phenomena that enabled a flood typology to be established and classified into seven categories, thus showing very different transfer dynamics in relation to flood events. The results showed that Category 6 floods presenting hysteresis in the form of a figure of eight exported almost 44% of the suspended particulate matter load while representing just 29% of the flow discharge.