Effect of land use/land cover changes on water quality in the Upper Athi River sub-catchment in Kenya

The unprecedented pollution of Athi River has negatively impacted the downstream communities who depend on the river's waters. Moreover, the Upper Athi River Catchment has recently experienced an increase in human population coupled with rapid industrialisation, which has led to encroachment of wetlands, riparian areas and forests. The objective of the present study was to investigate the impact of land use/land cover changes (LULCC) on the spatial-temporal distribution of water quality (WQ) in the Upper Athi River Catchment. The research stations were each allocated a GPS position, overlaid onto a 2018 LULCC map of the area. WQ data were analysed using PCA and further subjected to Kruskai-Wallls tests that resulted in six significant WQ parameters at (p < 0.05). The multiple regression model output showed that EC, DO, Zn and Pb, with R-2 values of 0.983, 0.918, 0.938 and 0.961 respectively, were significantly associated with urban area land use (p < 0.009, p < 0.042, p < 0.031 and p < 0.02 respectively). The results of our study suggest that significant land cover degradation is expected to occur in the Upper Athi River Catchment in future if mitigation activities are not undertaken, posing a great threat to biodiversity conservation, and the survival of local communities and urban dwellers in Athi River town.