Analysis of Watershed Attributes for Water Resources Management Using GIS: The Case of Chelekot Micro-Watershed, Tigray, Ethiopia

Abstract

This study identified the importance of watershed attributes for water resource management using ArcGIS software, ASTER DEM and satellite images for the Chelekot micro-watershed, Tigray, Ethiopia. The study also evaluate the different hydrological parameters which are significant for the water resource management within the micro-watershed and finds the alternative solutions for water harvesting in the study area through the introduction of suitable soil and water conservation structures based on the finding. Principal watershed attributes including drainage pattern, topographic parameters, land use types, and soil types were evaluated and interpreted for the study micro-watershed. ArcGIS software was used for the computation, delineation of the boundary and morphometric analysis of the micro-watershed using topographical maps and ASTER DEM data. Results indicate that the micro-watershed has classified as a dendritic pattern with stream orders ranging from first to fifth order. The micro-watershed has homogeneity in texture and lack of structural control of surface flow. The drainage density is medium which indicates the area contains soils with medium infiltration rates and moderate relief. Drainage texture, stream frequency and the form factor of the micro-watershed are 4.1, 1.7 and 0.4 respectively. The bifurcation ratio of the micro-watershed ranges from 1 to 4.5 and the elongation ratio is 0.7 which reveals that the micro-watershed belongs to the less elongated shaped micro-watershed category. The mean bifurcation ratio of the whole micro-watershed is 3.3 indicating that the drainage pattern is not greatly influenced by geological structures. The micro-watershed land covers includes: cultivated land (75.8%), settlement and open land (10.5%), shrubs and plantation (13.2%), and water body (0.4%). The major soil types are Vertisol (58%), Camisole (32%), Regosol (9.5%) and Luvisol (0.7%). The textural classes are clay (5%), silty clay (22%), clay loam (17%), sandy loam (21%) and loam (35%) based on the soil textural map of the micro-watershed. Our results revealed that using GIS and ASTER DEM data based watershed morphometric analysis and hydrological evaluation at watershed scale is more applied and precise compared to other available techniques .