Morphometric Analysis of Offin River Basin using Remote Sensing and GIS Technology in Ghana

Abstract

The paper examined morphometric characteristics of Offin River Basin in Ghana using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data with 30 m spatial resolution was used for the study. Different morphometric parameters including stream order, stream length, bifurcation ratio, relief ratio, drainage density, stream frequency, drainage texture, form factor, circularity ratio, elongation ratio, infiltration number and ruggedness number and their impact on hydrological processes such as infiltration, runoff, peak flow, overland flow and erosion in the Offin River Basin were discussed. The result revealed that Offin River Basin exhibited a dendritic drainage pattern with higher values of drainage density (13.02 km/km2), drainage texture (9.60), infiltration number (8.07) and ruggedness number (7.26). These values make the basin prone to structural control, high surface runoff and more susceptible to soil erosion and recurrent flooding. Morphometric study of the five major watersheds in the basin also indicated that the watersheds are prone to soil erosion and high runoff generation associated with flatter peak flow creating conductive environment for watershed conservation measures. The results obtained in the Offin River Basin and it watersheds could serve as a valuable empirical data for building a robust physical soil and water resources conservation structures and management plan for sustainable basin and watershed management.