Spatio-Temporal Land Use Land Cover Changes in Moiben River Watershed (1990–2021) and Impacts on Hydrology

Abstract

This paper investigates the spatio-temporal changes in land use and land cover (LULC) and their hydrological implications in the Moiben River Watershed, Kenya, from 1990 to 2021. Remote sensing and GIS tools were used to map LULC for 1990, 2005, and 2021, while hydrological simulation was conducted using the Soil and Water Assessment Tool (SWAT). The findings show that land use and land cover in the Moiben River watershed shifted significantly between 1990 and 2021. Over this period, agricultural land increased by 78.7%, primarily at the expense of natural forests, grasslands and bushlands, which declined by 40.9%, 38.8%, and 38.4% respectively. Hydrological modeling reveals a strong connection between these LULC changes and river flow dynamics. A simulated scenario converting 50% of agricultural land back to plantation forest demonstrated a beneficial impact on the watershed's hydrology, increasing dry-season base flow and moderating wet-season peak flows. These results suggest that LULC changes, particularly agricultural expansion, have significantly altered hydrological responses in the watershed. Sustaining the watershed’s ecological and hydrological integrity therefore requires integrated land management that balances agricultural production with conservation, supported by strong policy action and collaborative engagement among government agencies, communities and conservation partners