Evaluation of flood protection measures: case study of the Aït Athmane Center in the Draa-Tafilalet region (Morocco)

The risks associated with climate change are increasingly threatening the development of poor and marginalized populations. Extreme climatic events like floods can affect vital sectors such as water, agriculture, infrastructure, and ecosystems. Our study focuses on the risk of flooding in Aït Athmane, located 28 km north of Errachidia, Morocco. This region is particularly vulnerable to flooding and overflows from the Ziz Wadi tributary that crosses the Aït Athmane territory. The specific aim of this study is to assess the consequences of flooding in this locality and to propose several adaptation measures. The methodology followed consisted of GIS processing for hydrological analysis of the basin and statistical analysis of maximum daily rainfall at the “Foum Tillicht” rainfall station using HyfranPlus software and applying various empirical formulas to estimate peak flow. A hydraulic simulation was then carried out, which is a crucial step in interpreting these values for Aït Athmane Wadi, a tributary of the Ziz Wadi, using the “HEC-RAS” hydraulic modeling software. Maps were generated using GIS software, and their superimposition was used to locate potentially flood-prone areas. The results show flows ranging from 60.13 to 92.69 m³/s for different return periods, with a main river length of 10.08 km and a concentration time of 125.55 min. Hydraulic analysis shows a risk of overflow, threatening local populations and their crops. These floods can reach 3 m in some places. Several measures have been identified and proposed to mitigate the impact of this significant hazard. These mainly involve simple mechanical corrections such as raising retaining walls along the banks of the Wadi, installing gabion weirs, and designing crossing structures.