Gis tools and numeric model to forecast the floods extend along the Rhouireg river, city of Taza, Morocco

Abstract

Combining GIS tool with physical-based model is one of the most effective ways to locate flood-prone zones. In this study, we used a 1D hydrodynamic model to predict the extent of future floods and eventually present the floodable areas on a satellite image covering a densely populated section of the Rhouireg river, located in the eastern part of Taza city. We fed the model with peak flows calculated using the Rational method, estimated variables using standard tables (Manning's coefficient), and other field-measured parameters. We calibrated the model with minor adjustments that were necessary to accurately match the observed floods. Our findings revealed that the covered canal was sufficient to evacuate water during 10- and 20-year floods. The 50- and 100-year floods overflowed the canal and affected National Road No. 6, posing a danger to road traffic. Like this section, the upstream part demonstrated that the decadal frequency flowed through the channel without overflowing its banks. The centennial flood inundated the riverbeds, spreading large amounts of water into inhabited areas and cultivated fields. These results align with the flood that occurred on January 14, 2010, and confirm our previous observations, indicating that the model precisely anticipated the river's behavior. The numeric simulations have also proven to be an incredibly powerful tool for conducting a detailed assessment of flood risks along this small wadi.