Morphometric analysis of wadi Khumal basin, western coast of Saudi Arabia, using remote sensing and GIS techniques

Wadi Khumal, a triangular drainage system basin located at the Radwa Mountains of the south Red Sea, Saudi Arabia, has been chosen to assess certain morphometric parameters that influence water supply for basin hydrology. Shuttle Radar Topographic Mission (SRTM) information was used to produce Digital Elevation Model (DEM), aspect network, and descent graphs. Geographic Information System (GIS) is utilized for the assessment of linear, areal, and relief landmarks of morphometric aspects. Morphometric analysis of the drainage system network and the Khumal basin showed it has fifth-order wadi network with an elongated shape and possesses dendritic to sub-dendritic drainage pattern. These pattern points in the Khumal basin have similarity of lithology, moderate to steep slope, and an effective structural system. The various values of bifurcation ratios (Rb) versus low form factor results with circularity ratio (Rc) and elongation ratio (Re) highly suggested a geologically higher permeability and a structurally planned drainage system through intermediate to low drainage density (Dd), moderate stream frequency (Fs); moderately coarse drainage texture (Rt) with high relief indicates tectonic activity with high slope terrain made from loose materials with good permeability efficient for the recharging of ground water. The low value of asymmetrical factor (AF) showed great distortion quotient of the lithology in all sub-basins proving the great and broad tectonic influence in the Khumal basin. A high relief ratio (Rh) of 0.028, with low zigzag path and a highly steep ridge during the Khumal basin indicated a continuation of youth of the basin with continuously local uplifting. A very low value Rt of 0.646 versus a very low Fs of 0.177 and a Dd of 556.33 m/km2 demonstrated that the basin was having extremely resistant rocks in a very high relief ground which indicates late tectonic activity.