Causes of Nun River Bank Erosion at Okoloba in Kolokuma-Opokuma Local Government Area, Bayelsa State, Nigeria

Abstract

This study is aimed at identifying the causes of the Nun River bank erosion at Okoloba. With respect to the concept of geomorphic and anthropogenic interrelationship, the study employed a direct field contact methodology which led to the application of field measurements, soil sample analysis, and personal observation and interview. Following this, the study discovered that, the Nun River bank erosion at Okoloba is a function of un-consolidated bank materials , sinuous meandering at the Okoloba reach, high stream velocity, presence of underground erosion induced by groundwater flow from the backswamps, steep gradient of the bank, run-off pattern to the river and, effects of such anthropogenic activities as building and cropping near the banks and sand-mining near the banks and along the stream channel .In conclusion, the work recommended a professional and comprehensive assessment of the study area, as well as public enlightenment of the inhabitants as surrogates of mitigation in the area.

Keywords: Riverbank, erosion, stream velocity, bank gradient, geomorphic factor and anthropogenic factor