Quantification of Morphometric Analysis using Remote Sensing and GIS Techniques in the Qa’ Jahran Basin, Thamar Province, Yemen

Abstract

Demand for irrigation water increases day by day along with meteorological vagaries and extension of irrigated area in the drought-prone Jahran district. The study is aimed at studying the morphometric parameters of the Qa#39 Jahran basin in Jahran district and on their relevance in water resource management. The drainage network was prepared from the ASTER (DEM) and verified with survey and mineral resources board of Yemenrsquos maps in GIS environment.Quantitative morphometric analysis was carried out for different sub basins for linear aspects, areal aspects and relief aspects.The results of the morphometric analysis reveal that the QarsquoJahran basin is of dendritic pattern, high erosion activity, basin is underlined by uniform materials, basin is flat, Drainage density is moderate spacing streams, permeable sub soil materials with dense vegetated cover and low relief (alluvial plain), susceptible to flooding, gully erosion, enhanced ground water recharge potentiality, Form factor and circularity ratio results represent an elongated shape, have a flatter peak flow for longer duration and drainage system were subject to less structurally controlled on the drainage development in over all the basin, low relief for most portion of the basin, high surface runoff and high susceptibility of the basin for both soil erosion and flooding.The higher slope gradient in the study area is contributed by the eruption of basaltic flow in northern, eastern and western parts. Higher slope gradient results in rapid runoff with potential soil loss or erosion. The Qa#39 Jahran basin relief value is 110m for sub basin 1 to 640m for sub basin 2 indicates low infiltration and high runoff conditions. The ruggedness number ofthe subbasins 1 and 2 indicates higher soil erosion susceptibility