Hydrologic and morphometric analysis of Ofu River Sub-Basin using remote sensing and Geographic Information System

Abstract

The morphometric characteristics of a river basin are very important factors in watershed hydrology. The morphometric analysis of the Ofu River sub-basin was carried out in this study to assess its morphologic and hydrological characteristics as well as its flood potentials based on the morphological characteristics. The study was carried out using remotely sensed spatial data analysed using Geographical Information Systems (GIS). The morphometric parameters analysed were the areal, linear, and relief aspects of the sub-basin. The results showed that Ofu river sub-basin covers a total area of 1604.56 km 2 and a perimeter of 556.98 km covering parts of Kogi and Enugu States in Nigeria. The sub-basin has 3rd order river network based on the Strahler's classification with a dendritic drainage pattern and moderate drainage texture. The values of bifurcation ratio, drainage density, circularity ratio, elongation ratio, form factor, stream frequency and drainage intensity indicate that the sub-basin is elongated and would produce a flatter peak of direct runoff for a longer duration implying that the sub-basin is morphometrically less susceptible to flood and that any flood flow that may emanate from it would be easy to manage.

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“…These imply that while it takes a drop of water about 6.17 hours to flow from the remotest part of the catchment to the outlet, it will take almost 4 days for flood water to recede from the watershed. The detailed morphometric characteristics of the watershed have, however, been previously reported in Alfa et al (2019).…”

“…The main river within the sub-basin (Ofu) is perennial and parallel in pattern to the Imabolo and Okura rivers, which are close to the study area. It took its root from Ojofu, in the Dekina Local Government area of Kogi State, flowing in an eastward direction with a catchment area 2 amounting to about 1,604 km most of which is covered by dense forest (Alfa et al, 2019). The Okura River joined the Imabolo River in Egabada (Kogi State) and further flowed southward before joining the Ofu River, and the 'three-in-one' river empties into the famous Anambra River in Anambra State (Gideon et al, 2013).…”

Assessment of stream order and drainage pattern of flood prone areas of Ebonyi State Southeastern Nigeria

“…The drainage network is the fundamental hydrologic and geomorphic areal unit through which a detailed description of the geometry of landforms where data are collected, organized, and analyzed (Chorley, 1969). The systematic description of the geometry of a drainage basin and its stream channel requires measurement of linear aspects of the drainage network, areal aspects of the drainage basin, and relief (gradient) aspects of the channel network and contributing ground slopes (Alfa et al, 2019;Salvi et al, 2017). Therefore, the usefulness of the stream order system depends on the premise that, on average, if a su ciently large sample is treated, the order number is directly proportional to the size of the contributing watershed, to channel dimensions, and to stream discharge at that place in the system (Shankar et al, 2014).…”

Mapping of GIS-Flood Hazard Using the Geomorphometric-Hazard Model: Case Study of the Al-Shamal Train Pathway in the City of Qurayyat, Kingdom of Saudi Arabia

“…The higher the morphometric number of the basin, the higher the basin's hazards. Several studies have used the geomorphological ranking method to determine the drainage basins exposed to flood hazards [10][11][12][13][14][15][16][17][18].…”