Morphometric And Drainage Characteristics of Selected Sub-Basins in The Lower Benue Basin, Nigeria
Solomon Terlumun Kwaghkule, Patricia Ali, Monday Akpegi ONAH* and Johnson Orfega Mage
This study analysed the morphometric and drainage characteristics of six selected sub-basins of the Lower Benue Basin, Nigeria, namely Katsina-Ala, Mada, Farin Ruwa, Dep, Mu and Shemankar, to assess their drainage organisation, geomorphic development and implications for runoff response and flood management. Digital Elevation Model (DEM) data were processed using Geographic Information System (GIS) techniques to delineate drainage networks and derive linear, areal, relief and hypsometric parameters. Results revealed substantial spatial variation in drainage characteristics. Katsina-Ala was the largest sub-basin (12,139 km²), with 14,861 stream segments, seven stream orders and a total channel length of 1,623.83 km, while Shemankar was the smallest (298.41 km²), with 369 streams and five orders. Drainage density varied markedly from 0.134 km/km² in Katsina-Ala to 4.697 km/km² in Dep, with Shemankar also recording a relatively high value of 2.475 km/km². Form factor (0.16–0.27), elongation ratio (0.45–0.58) and circularity ratio (0.24–0.39) indicate predominantly elongated basin forms. Dep recorded the highest ruggedness number (10.01) and shortest overland-flow length (0.11 km), indicating high potential for rapid runoff concentration, whereas Katsina-Ala exhibited lower runoff concentration potential. The findings demonstrate considerable morphometric heterogeneity and provide a useful basis for sub-basin-specific flood and water-resource management.
