استخدام نموذج الارتفاع الرقمي DEM في تحليل المتغيرات المورفومترية لحوض وادي لبدة

Abstract

This study dealt with the Lebda Wadi Basin located in the Northwestern Libya. The study analyzed the Digital Elevation Model (DEM) of the Wadi Basin. The study aimed at identifying the natural characteristics as well as the morphometric features of the basin. The results obtained have shown that the length of the basin was found to be (21.35 Km), and its maximum width was (9) km. The total area of the basin was found(189.579) km²). The analysis of the digital elevation model showed that the prevailing direction of the slope in the basin is northeast by (25.5%) and the drainage network in the Lebda Wadi Basin consists of 693 water courses, with a total length of (444.53) km and one (1) streams for the sixth class. There were two (2) watercourses for the fifth, (7) water streams of the fourth rank, and (540) water streams for the first order. The roundness ratio of the basin was (0.35), which indicates that the shape of the basin is far from the circular shape, and the ratio of the dentition was (14.71 m/km). The response time (concentration) reached(4.5) hours, which, means that the time needed for the water to reach the exit of the valley from its farest point is four and a half hours. This is a clear indicates the high speed of the water flow, due to the short distance and steepness of the valley slope or gradient.