Журнал географии и стихийных бедствий
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Hypsometric Curve of Watersheds in Southern Part of Al Jabal-Al Akhdar Area, North-East Libya

Jamal Zamot*, Mohammed Afkareen

Hypsometric analysis is the study of the relationship between horizontal cross-sectional drainage basin area and elevation. The hypsometry of drainage basins has been assessed in an attempt to simulate the stages of geological maturation and to study the influence of varying forcing factors (i.e., tectonics, climate, lithology) on watersheds. The shape of the hypsometric curve provides valuable information on the erosional stage of the basin, and also on the tectonic factors controlling it. Comparisons of the shape of the hypsometric curve for different drainage basins under similar hydrologic conditions provides a relative insight into the past soil movement of basins. In addition, calculating the Hypsometric Integral (HI) is a suitable method to describe the form of the hypsometric curve for a particular drainage basin. In this study, hypsometric analysis of four sub- basins in southern part of Al Jabal Al Akhdar area, NE of Libya, is carried out using DEM of 90 m resolution by SRTM. The elevation ratio was used to evaluate various hypsometric integral and establish the geological stage of water development. According to generated results shape of hypsometric curves of four hydraulic sub- basins significantly differs from each other. The geological stages of water developments in these sub-basins are ranging from the young to the old stage. HI values are ranging from 0.28 to 0.56 show different stages of watershed erosion; from fully stabilized to highly susceptible of erosion. Differences on hypsometric curve and HI values may provide information about tectonic effect on the given hydraulic basins.