GIS & Remote Sensing Based Morphometric Parameters and Topographic Changes of the Lower Orashi River in Niger Delta

Abstract

In watershed hydrology, the morphometric features of a river basin are vital to examine the lower Orashi River basin morphological and hydrological aspects, as well as its flood potential, based on their morphometric characteristics using remotely sensed SRTM data that was analyzed with ArcGIS software. The areal, linear, and relief aspects of the Orashi River basin were examined as morphometric parameters. The lower Orashi river basin, according to the findings, has a total size of 625.61 km2 and a perimeter of 307.98 km, with a 5th order river network based on Strahler categorization and a dendritic drainage pattern. Because of low drainage density, the drainage texture is very fine, the relief is low, and the slope is very low. Bifurcation ratio, circularity ratio, drainage density aspect ratio, form factor, and stream frequency values indicate that the basin is less elongated and would produce surface runoff for a longer period, while topographic changes show that the river is decreasing with depth in the land area at about the same elevation as a result of sand deposited due to lack of maintenance by dredging, which implies that the basin is morphometrically elevated and sensitive to erosion and flooding. To understand geohydrological features and to plan and manage watersheds, morphometric analysis based on geographic information systems and remote sensing techniques is beneficial.