The use of remote sensing and gis in assessing the impact of land use change on soil erosion of Mhlathuze catchment, South Africa

South Africa is generally a water poor country with a mean annual rainfall of 464 mm. The low rainfall regime has exacerbated the water demand to surpass the supply in many areas causing hydrological consequences. Increasing signals of environmental degradation such as erosion is one of the biggest problems that the country is currently grappling with. Mhlathuze Catchment, one of the small catchments in the province of KwaZulu Natal, has been faced with erosion and sedimentation problems that have largely been attributed to agricultural activities and industrial development. Water quality studies have been conducted in this catchment, but the changes of land use has never received much attention. This study aimed to assess the impact that the changes in land use have on the erosion in the catchment. A time-series (1992, 2000 and 2014) of satellite images was classified using the Maximum Likelihood Classifier in order to distinguish between the different features in the catchment. The most glaring land use changes were the increases in cultivated land and commercial forest. Erosion estimation was carried out using the classified images in RUSLE model. The mean annual soil loss for the year 1992 was found to be 32.12 t/ha compared to 16.08 t/ha and 15.25 t/ha for 2000 and 2014 respectively. The study found that the most vulnerable areas are the ones under cultivation as the top soil is loosened by the agricultural activities. From these results, and in view of the damage that the changes in land use are envisaged, it was recommended that a GIS database system is established and kept up-to-date.