The impact of land use change on runoff and peak flood discharges for the Nyando River in Lake Victoria drainage basin, Kenya

Abstract

The effects of land use changes on the characteristics of floods in the Nyando River basin were investigated. Historical changes in the state of land cover were derived by processing multi-temporal Landsat images. The detected changes, together with other spatial datasets were subsequently used to estimate the physically based catchment and hydrologic model parameters for runoff generation and transformation, and for channel flow routing. The results obtained indicated that the basin experienced significant increases in peak discharge values, especially in the upstream areas where higher rates of deforestation were detected. Over the study period, the peak discharges increased by 16% in all of the 14 sub-catchments in the basin. Simulated flood volumes in the basin also increased by 10% over the same period. Based on the results obtained, the study outlined the consequences of land use change for flood events in the basin. © 2011 WIT Press.