Jornal de Hidrogeologia e Engenharia Hidrológica

Numerical Model for Flood Hazard Forecasting in an Urban River of Taza City, Morocco

Badr Layan, Mahmoud Zemzami and Brahim Bougdira

Forecasting flood hazards is essential for locating vulnerable places, measuring flood effects, anticipating possible damages, and investigating mitigation options. Attempting to anticipate flood dynamics at various return periods, this work employed the river simulation model over the highly populated section of the Jaouna Wadi (River) in Taza city. The model's inputs included future floods calculated utilizing a rational method, physical variables approximated using standardized tables (Manning coefficient), and other inputs directly measured in the field. The stability of the model demonstrated that its parameters had been precisely assessed. The outputs were compared to the observed floods during the calibration phase, and any necessary corrections were performed to guarantee that the model reproduced results within a reasonable range. Our findings revealed that the covered channel was insufficient for evacuating water during decadal floods. Aside from this section, the 10-year floods flowed through the opened channel without spilling over its banks. The 100-year floods ran over the channel's banks, spreading large amounts of water to inhabited zones and cultivated fields. These results were in accordance with recent floods and also supported evidence from previous observations, indicating the accuracy of the prediction of the Wadi’s behavior. The study signifies that the model is a powerful tool for detailed flood risk assessment, especially in limited areas.