Abstract:
In this study, surface runoff and evapotranspiration, simulated by the Soil and Water Assessment Tool (SWAT) for Narok North Constituency, Narok Town, are analysed at the spatial level of hydrologic response unit (HRU).The three set objectives were fulfilled. HRU analysis involved preparation of 12.5m of DEM data which delienated the basin and generated slope, FAO soil, meteorological data and remote-sensed landsat images classified to produce land use land cover. Surface run-off was found to vary reasonably with land use, soil types and slope. Correlating surface run-off and land use produced positive results for bareland and built –up while producing almost negative results for plantations, forest and riverine vegetation. Some of the factors influencing storm water occurrence and run-off were characterised as social-cleared land for settlement purposes, economic-cleared land for agriculture, overgrazing and climatic-for climatic changes over time. Management of water impacts using SWAT analysis is important since multiple environmental processes are integrated which support more effective watershed management and the development of better‐informed policy decisions.