Impact of land use change on surface runoff and stream discharges in Luvuvhu River Catchment

Abstract

Luvuvhu River catchment in Limpopo Province of South Africa experiences floods resulting from heavy rainfall of intensities exceeding 15 mm per hour associated with the Intertropical Convergence Zone. The generation of runoff is triggered by the rainfall intensity and soil moisture status. Runoff was calculated as a product of the net precipitation and a curve number coefficient. It was then routed using the Muskingum-Cunge method through the basin along flow paths determined by the topography using a diffusive wave transfer model that enabled the calculation of response functions between start and end point, depending upon slope, flow velocity and dissipation characteristics along the flow lines. Results showed that the simulated discharges closely compared with the measured discharges without the need for model optimization. It was concluded that simulation techniques had the potential to determine the influence of changes in land use to the hydrologic response of the catchment.