Assessment of land use land cover change and water physical parameters in River Rwizi Cachment, Mbarara District

Abstract

The Rwizi river catchment is a high value landscape covering 10 districts of western Uganda. The catchment has faced large scale human induced land use and land cover changes, which has led to loss of vegetation cover and its effect on water parameters. This study was aimed at assessing land use and land cover, community perceptions on these changes and the association between these changes with water physical parameters in the catchment. A combination of satellite imagery were interpreted to construct LULC cover dynamics in the catchment for the years 1999, 2010 and 2020. The results from both satellite image analysis and community perceptions showed large trends of LULC changes, which have occurred rapidly over the last 20 years. The most dominant LULC changes were a net gain in built up/ bare land from 29% to 36% between 1999 and 2010, and a reduction in grassland from 29% to 22% between 2010 and 2020. Restoration of wetlands and afforestation efforts resulted into an increase in dense vegetation between 2010 and 2020. This is one of the few studies in River Rwizi catchment scale that combines multi-source spatio-temporal data on land cover to enable long-term quantification of land cover changes. The findings demonstrate the need for restoring wetlands and afforestation and as well as research to quantify sediment load and deposition in this river catchment. The findings might be used by relevant authorities for informed decision making on planning for erosion and sediment control interventions and improving the productivity of the River Rwizi.