Modeling Land-use and Non-point Source Pollution: Assessing Impacts of Land-use Change on Non-point Source Pollution of Lake Victoria Using Swat Model

Pollutant loading in Lake Victoria is resulting from a wide range of human activities. Most attention has however been drawn to the pollution caused by point- sources like industries and sewerage works. Other land-based activities which are generally referred to as non-point sources of pollution have not received adequate attention. This book identified major sources of NPS pollution in the Simiyu catchment of Lake Victoria and using land-uses of 1975 and 2006 compared the relative impact of land-use change on nutrient load (P and N) into the Lake. Possible BMP were also identified for those sub-basins with the highest pollution yield. Remote sensing was used to identify and charaterize the land-use and the Soil and Water Assessment Tool was used to quantify sediment and nutrient load from these two different land-use scenarios. It was found- out that there was an expansion of agricultural land at an annual change rate of 2.9%. If pollution processes per sub-catchement could be understood, BMP could be deviced depending on the sub-basin which would have a big collective reduction in NPS pollution in the whole catchment.