Application of Remote Sensing and Runoff Modelling to Identify Environmental Conservation and Water Harvesting Sites

Land cover has changed variably in Athi Catchment Area as a result of environmental and human activities. The Catchment hydrological response has also changed resulting in high surface runoff, depleted ground water, flash floods and soil erosion during rainfall events. This study assesses the land cover change extent and its impact on surface runoff in upper Athi Catchment Area, between 1990 and 2013, using remote sensing, GIS and hydrological modelling in order to advice on catchment conservation options and identify areas water harvesting potential. Satellite images from Landsat 7 ETM+ and Landsat 8 were classified using ERDAS Imagine, change detection analysis in Terrset and runoff modelling using ArcSWAT Model. The study results showed overall decrease of forest cover and an increase of settlement and grassland and increased runoff values in the areas that experienced conversion forests to cropland, shrubland and grassland. Areas with increased forests with reduced shrubland and cropland recorded decreased runoff values in some cases. This study aims at opening viewpoints concerning land cover change impact on runoff, and alternatives that can be adopted for sustainable land and water resource use