Salt intrusion and suspended material dynamics at a river-seawater interface: Flood- and low-water stages in the Qued Mazafran (West Algeria)

In the lowest part of the Oued Mazafran Valley, the entry of saltwater creates a salt wedge. This structure can be found upstream as far away as 5 km from the river mouth during the low water stage when the river flow is zero. The river-seawater interface is indicated by the water reverse ionic composition. The river suspensions react to this salt wedge in two ways: First, from a dynamic point of view, the flow becomes equal to zero at the upstream limit of the salt wedge, inducing the deposition of part of the suspension due to excess load. The second is an electrochemical reaction which causes the finest and reactive part of the suspended material to flocculate through the interface.