Flood Hazard Assessment and Risk Management in Dar Belamri: A Hydrological and Hydraulic Approach for Effective Urban Development and Slum Reduction

Abstract

Dar Belamri is considered one of the emerging centers in the Sidi Slimane region, but it suffers from the spread of slums in the center, especially in the Ouled Abdel Sadek area, part of which is located on the edge of a cliff near scattered quarries, in addition to the Fajr area, which is located near the Beht River. What distinguishes these areas is that they are located in a natural flood zone, which requires proactive management of these risks by local planners and decision-makers. This study provides a flood risk assessment tool that is adapted to the conditions of these specific areas. The methodology combines flood frequency and flood impacts using a hydrological and hydraulic approach. This approach uses a hydrological model to analyze the spatio-temporal evolution of hydraulic properties (such as flow rate, velocity, water height, and inundated areas) during design flood events, while assessing the effects of hydraulic developments on flow dynamics. The study focuses on two main watercourses, Wadi Beht and Wadi Oum El Zein. Comprehensive topographic surveys provided detailed morphological data, allowing for accurate hydraulic simulation of floods at different return periods. This helped accurately identify flood zones and contributed decisively to the delineation of areas suitable for urbanization and construction, thus producing a flood risk map. It is a crucial tool for targeted flood risk management and mitigation efforts, ultimately supporting the development of a final urban suitability map and, through it, identifying appropriate solutions for informal housing and avoiding various risks in the center of Dar Belamri, with the potential for application across other high-risk areas.