Assessing the effect of agricultural practices on the stream flow with in River Manafwa catchment.

Abstract

Land use plays an important role in controlling hydrologic response of catchment, particularly in terms of the nature and magnitude of surface water and ground water interactions and surface water availability. The change in land use controls the water yield of surface streams and ground water aquifers and thus the amount of water available in a watershed. In the Manafwa watershed located in eastern Uganda, agriculture land use has been noticed to be highly practiced, river. This study therefore focused on assessing the impact of water abstractions on the streamflow and also suggested better management measures for sustainability of River Manafwa Soil and Water Assessment Tool(SWAT) was applied for determining agricultural Water requirement and Hydrologic Engineering Centre Hydrological Modelling System (HEC- HMS) was also applied to develop a precipitation run off model for Manafwa catchment. The Stream flow response to different land use changes was also simulated using HEC-HMS and the land use changes included restoration of wetlands and reforestation agriculture water demand for paddy rice was found to have 5.3% and.5.2% effect on the stream flow of river Manafwa for season one and two respectively. Restoration of wet lands and reforestation would be better management strategies within Manafwa catchment as they would positively Influence the hydrology of River Manafwa hence sustainability.