Using GIS to develop a management plan for Tana river basin in Embu and Mbeere districts

Abstract

This study revolves around Ena River Basin, one of the significant basins on the Eastern side of the renowned Mt. Kenya that lies between 00E, 330N and 00E, 370N, and contributes to the catchment for Tana River, Kenya’s largest river that is used for among other purposes, hydroelectric power generation. In the recent past, the Tana basin has experienced significant flow reductions, caused by among other issues, massive degradation in the basin area. The objective of the study is to therefore identify causes to this issue, and to use a GIS based analytical model to spatially analyze the basin, with a particular emphasis on the coffee zone that falls in the middle stage of the Ena River development. Using the Ena River Basin Management Model (ERIBAM), a GIS based management tool that combines River flow data, Sediment Load, Soil pH and Slope and Elevation units, the study results spatially represent in a cellular form areas affected by this degradation, with suggested recommendations on how to deal with the resultant issues. This model has borrowed heavily from the Revised Universal Soil Loss Equation (RUSLE), developed by Renard et al, in 1991 and is an accepted worldwide GIS-based analytical model. As with process-based models however, the ERIBAM model has limitations due to temporal variations in its inputs as discussed in the study.