Quantitative Analysis of Watershed Geomorphology and its Hydrological Implications Using GIS: Case Study of Billi Drainage Basin, Egypt
Abstract
Since there is a direct relation between the geomorphological characteristics and the hydrological processes within the drainage basin, it’s important to develop a morphometric database as a primary step to understand the context of landform development; its characteristics; and the pattern of its contribution to the hydrological system, especially when there is a lack in the hydrological data. Several studies cited conventional approaches of field investigation or using topographic maps to derive the necessary parameters. However, using of Digital Elevation Model integrated with GIS environment can save time, effort, and provides accurate results. The aim of this paper is to analyse numerically the geomorphological characteristics of Billi drainage basin, Egypt, and its sub-basins in details through deriving more than 80 morphometric parameters of all aspects and evaluate their hydrological implications, to develop deep understanding of the main differences and similarities with other regions in term of flow generation processes. The results refer to monadnock stage of development cycle indicating the attainment of a stable state in the processes of erosion and transportation within the drainage network and its contributing slopes, and a system of channel slopes and valley wall slopes has been developed. The range of values of the sub-basins shows moderate to high drainage density indicating gullied slopes and surface of low permeability. So, it’s recommended to implement a detail hydrological study, followed by a statistical analysis to evaluate quantitively the weight of each morphometric parameters and analyse its contribution. This paper offers a morphometric database that can be used in sustainable management of water resources and future planning applications of rain water harvesting and flash flood risk assessment.