Hydrological investigation and hydraulic modeling of floodable areas in the Aghbar center, Al Haouz province, Morocco, using HEC-RAS (1D, 2D)

Abstract

The study presents flood modeling of Aghbar's center, which is part of Al Haouz province, and the basin of N’Fis, using HEC-RAS one-dimensional and bidimensional models. The research's aims are to designate flood-prone zones at the study area level of 94.3 HA in order to provide the center with all of the essential facilities for the upgrading of its local population. The hydrological study of the basin was carried out in order to calculate the flood flows according to the various periods of return (10years, 20years, 50years, 100years) using several methods, the Gradex method provided a good finding, where the centennial peak flow was 1151.55 m3/s. During the hydraulic phase, the Wadi's water height and flow velocity were computed using one-dimensional modeling (1D) with a 100-year flow as a reference flow using HEC-Ras 5.0.7. These two parameters were also calculated using a two-dimensional modeling (2D) that allowed the fluvial flows to be modeled, resulting in a comparative synthesis between the two models, with the goal of proposing subsequent schemes of flood protection for the Aghbar Center and reinforcing the already existing hydraulic works. The one-dimensional modeling at the end of the mapping of floodprone areas at the level of the center of Aghbar shows that Douar LAMKAYT is protected from the risk of flooding, whereas the center of Aghbar will be affected, allowing us to propose protective measures at the level of this center such as gabions and protective walls.