Impacts of land use and land cover changes on Chepkaitit and Moiben rivers’ watershed along Trans nzoia, Uasin Gishu and Elgeyo Marakwet Counties, Kenya

Abstract

ncluding watershed degradation. The major causes of watershed degradation are extensive deforestation and poor soil and water conservation measures. River flow discharge is influenced by LULC changes, soil and water conservation measures and managerial practices applied by farmers and further compounded by the growing human population. This study was conducted in Chepkaitit and Moiben Rivers‘ watershed located along Trans Nzoia, Uasin Gishu and Elgeyo-Marakwet counties in Kenya. The specific objectives were to establish LULC changes in the years1980, 2000 and 2020; so as to determine how change in LULC types influences river flow and to analyze the kinds and level of soil and water conservation measures applied by residents. The common property Theory was used to guide the study. The study used descriptive and correlational research design and the data was both primary and secondary. The target population under study was 96,746 household heads and a sample size of 383 household heads was used to fill in the paperless questionnaires developed and deployed in the kobo toolbox. Stratified random sampling technique was employed for the survey and the cleaned data was analyzed using SPSS software. The LULC change analysis used data from Landsat satellite imagery downloaded from United States Geological Survey website while the Soil and Water Assessment Tool model was used to quantify the impacts of river discharge variability under base scenario (1980 LULC), scenario 2 (100% agriculture LULC) and scenario 3 (100% Forest). The SWAT model used weather data downloaded from the ―Global Weather data for SWAT‖ website and DEM (slope data) downloaded from USGS website while model output calibration used SWAT-CUP. The study found out that there were great changes on LULC on the study area within the period of study. The natural forest, bush land and wetland had reduced by 13%, 95% and 67% respectively while cropland and plantation forest had increased by 69% and 32% respectively. The study also found out that changes in the LULC types significantly influenced the river discharge with R 2 of 0.89 at p= 0.00001 with a significant level of 0.05. The change in river discharge was more pronounced in April where scenario 2 river discharge varied by -28.51% and 19.57% for scenario 3. The research further established the soil and water conservation measures as contours, gabions, minimum tillage, tree planting and strip cropping. The study concluded that there were significant changes in LULC types in the study periods, the LULC changes influence on river discharge was significant with synchronized flow under forest cover and all farmers were applying some form of water and soil conservation measures in their farms. The study recommends that afforestation be prioritized especially in the steep slopes, while the riparian vegetation should be conserved as required by the policy guidelines and farmers to be encouraged to practice conservation agriculture.