Digital Elevation Model-Derived Morphometric Indices for Physical Characterization of the Issen Basin (Western High Atlas of Morocco)

Abstract

This study attempts to describe the physical characteristics of the Issen basin (western High Atlas of Morocco) to represent the factors affecting water flow and volumes that may increase water erosion risk. By using ALOS-DEM of moderate resolution spatial (12,5 m) and GIS platform, it was possible to provide a joint set of morphometric indices of the stud area. The obtained results reveal the mountainous symptom of its relief and the state of maturity of its basin. The contrasting topography (625m to 3528m), a specific unevenness of the order of 612 m, highlights a strong relief. 94% of the watershed area has a slope of over 3%. The mean elongation of the basin is 1.74, with a fairly long water concentration time of about 7.5 hours and an average drainage density of 0.85 km-¹. The combination of tectonics, lithology, and external geodynamics determines a strongly contrasted morphology characterizing the Issen basin. This situation also favors an increase in the volumes of water and the addition of sediments mobilized by the Issen Wadi which can increase the risks of soil loss and flooding.

Keywords

• watershed
• morphometric indices
• topography
• gis
• wadi issen
• argana corridor
• morocco