Relationship between River Flow Volumes and Changes in Land Cover, Land Use and Climate in the Mara Basin (1983- 2014)
Isaac Ayuyo
Faculty of Biological and Physical Sciences, Tom Mboya University, Kenya.
Clifford Okembo *
Department of Physics, Earth and Environmental Sciences, Technical University of Kenya, Kenya.
*Author to whom correspondence should be addressed.
Abstract
The Mara River Basin, a critical transboundary system within the Lake Victoria and Nile basins, sustains the globally renowned Mara–Serengeti ecosystem and diverse indigenous livelihoods. Land cover change, land use dynamics, and climate variability are recognized globally as the major drivers of hydrological instability and ecosystem stress. Africa is particularly vulnerable to climate change impacts due to widespread poverty and reliance on rain-fed agriculture. In East Africa, recurrent droughts and floods have been widely reported, with climate variability exerting strong pressure on water resources. The Mau Forest Complex in Kenya is facing deforestation despite being a vital water tower regulating flows into the Mara River thus, further destabilizes the Mara River hydrological regimes. Rapid population growth and land use conversion have driven forest excision and encroachment into fragile ecosystems, directly reducing river flow volumes. This study employed the use of Soil and Water Assessment Tool (SWAT) hydrological model, Multiple Regression and Correlation analysis, ANOVA, and scatter plot visualization to examine relationships between water yields and predictor variables of land use, land cover, and climate using long-term datasets (1983–2014) and projections to 2030. Results revealed a perfect model fit (R² = 1.000), with rainfall explaining 93% of river flow variability (r = 0.939, p = 0.010). Temperature (r = 0.061, p = 0.461) and forest cover (r = -0.670, p = 0.108) showed weaker, non-significant effects, though forest cover exhibited an inverse relationship with flows due to infiltration and evapotranspiration dynamics. ANOVA confirmed significant differences in water yields across land cover scenarios, while scatter plots provided visual validation of rainfall’s dominant influence. In summary, rainfall is the primary driver of flow variability, while land use and cover changes exacerbate extremes. Sustaining the Mara River’s ecological and hydrological functions requires urgent conservation measures, integrated watershed management, and climate adaptation strategies informed by both global science and local realities.
Keywords: Mara river basin, river flow volumes, land cover land use, climate variability, climate change, correlation, regression, sensitivity indices