Morphometric Features Analysis of Al-Sahol Valley ( North of Ibb city) Using GIS and Remote Sensing

Abstract

This study aims to analyze the formal and geometric characteristics of Wadi Al-Sahol Basin, using the digital modeling system with a spatial resolution of 30 meters, and relying on the Geographic Information Systems (GIS). The research location is Wadi Al-Sahol Basin, which is located southwest of Yemen, within the highlands region. The Western Mountain District is bordered to the north by the Wassab District in Dhamar Governorate, to the south by Al-Dhehar District, to the east by the districts of Hobeesh and Hazm Al-odin, and to the west by the districts of Yarim, Al-Makhader and Baadan.The study concluded that using spectral indices, that most of the basin is located within the dry zone, and the basin area is still in the early stage of its geomorphological cycle, and that the basin formed a fifth-order drainage network according to the Strahler classification. The study figured out that the basin was classified as within the rectangular-shaped basins, the majority of the sub-basins of all levels also tend to be elongated, which means a low probability of major floods occurring. This is due to the large area of ​​the basin, the nature of the terrain and slope, in addition to the permeability of surface materials and vegetation, and the widening of river courses, especially in the upper levels. The study recommended to rely on geographic information systems technology in modeling and analyzing drainage basins, because they provide less effort and cost in applying geomorphological studies as well as providing accurate and easy spatial and three-dimensional analysis.