Contribution of GIS and Remote Sensing in the Physical and Geomorphological Characterization of the Addouz Watershed, a Tributary of the Chichaoua River, to Enhance the Management of Hydrological Risks, Morocco.

Abstract

The analysis of various physical and geomorphological characteristics of the watershed aims at a quantitative evaluation of its shape, slope, orientation, relief, as well as the quantity and arrangement of the hydrographic network. A thorough understanding of these aspects will lead to a better grasp of the factors responsible for variations in hydrological regimes, thus contributing to the genesis of natural hazards and their temporal and spatial variability. Given the high frequency of flood risks in the Tensift basin, especially in its mountainous part, this study focuses on a comprehensive analysis of the ADDOUZ watershed. The objective is to determine the physical and morphological characteristics of the basin, a crucial step in understanding flow patterns and constituting a fundamental element before implementing flood protection projects. The results indicate that the Addouz river has a small watershed, with an estimated perimeter of 61.47 kilometers and an area of 69.34 square kilometers. Physical characteristics show an elongated shape with an equivalent rectangle of 24.90 km in length and 5.79 km in width. Hypsometric and slope analysis reveals flow oriented towards the north of the basin along the Addouz river valley. As for morphological parameters, they are used to understand flow and sedimentation patterns: depressional areas slow down flow, thus promoting deposition, while open slope areas act as catalysts for the risk of water erosion. The outcome of this characterization can guide hydrological stimulation efforts and assist decision-makers in choosing appropriate interventions for the development of flood-prone and erosion-sensitive areas. It provides an overall understanding of the behavior of the Addouz river during peak flow exceedances for given return periods.