ROUTING BLACK FLOOD HYDROGRAPH OF RIVER NIGER INTO KAINJI RESERVOIR

Abstract

Flood routing and hydrograph generation form key elements of Flood plain management. Flood routing reveals the magnitude of peak discharge, the time of the peak discharge and depth. Flooding along the river plain, especially river Niger and Benue is annual event. This attributed to both inflows within the country and transboundary flow. This study routed the inflow during the dry season at Jiderebode to Kainji reservoir. The study was carried out using kinematic wave model approach for flow between Jiderebode and Kainji on River Niger. The period of data gaps in flow record (2002-2012) was filled using recession equation. Advection equation and Kinematic wave model were coded in Microsoft excel. The length between Jiderebode and Kainji was divided into 21 sub reaches, each sub reach is 10 km. The catchment characteristics such as vegetation, topography and soil (manning’s roughness coefficient) were captured. The study revealed that kinematic wave model could be used to route the flow in river Niger. The Nash-Sutcliffe Efficiency (NSE) is 0.009, indicating that it is closely match with the observed inflow record at Kainji. The findings of these work would give better understand of the contribution of flow from upper and middle Niger Basins into Nigeria, during the dry season (black flood).