Evaluating ephemeral watercourse discharges by hydrologic-hydraulic modelling: application to the Kert River basin, Morocco

Abstract

Studying ephemeral watercourses situated in semiarid Mediterranean climate zones is a challenge in hydraulic and hydrological studies. Using SOBEK-River one-dimensional (1D) software, we modelled rainfall-runoff in rural areas, specifically in a portion of the Kert River basin near its mouth, to study its upstream hydrographic network and produced valuable modelled data for the torrential flood of 26 October 2008. This study is the result of a research project aimed at estimating the discharge on a coastline designed for the construction of a big harbor in Morocco. The use of SOBEK River 1D was necessary to make a decision on the direction of opening of the quays of this harbor. The watercourses studied were located in an ungauged basin, therefore, the need to use other methods to make a comparison. We compared the results obtained with the flows calculated by index flood assessments. The modelled discharges of the creeks were similar to the estimates of the discharges recorded elsewhere during this flood event; thus, similar models could be applied to similar semiarid climates worldwide. Our results show that rainfall-runoff modelling can be useful for approximating discharges in ephemeral watercourses.