Modeling of groundwater potential in Kericho County, Kenya, using GMS_MODFLOW

Groundwater is a major source of water supply in Kericho County, Kenya. However, this water source is threatened by the rise in the human population and climate change. Under these conditions, it is crucial to assess the sustainability of the groundwater resource in Kericho County. Thus, this study aimed to investigate the potential of groundwater in Kericho County, Kenya. Groundwater Modelling System (GMS) software was used to develop a conceptual model to aid in the assessment of groundwater. Results from calibration showed hydraulic conductivity values varying from 0.279 to 1.12 m/d, while the recharge rates ranged from 0.5 to 0.00022 m/d. Also, a predictive run was conducted in the calibrated model to examine the aquifer's response to abstractions under three different scenarios. Scenario 1 assessed the impacts of population growth on groundwater resources; scenario 2 evaluated the effects of climate change on groundwater; scenario 3 assessed the effect of population growth and climate change on groundwater in the study area. The results showed that excessive pumping rates interfere with the surface water and groundwater interactions. There was slight decline in constant head for location near the river. However, the recharge rate was higher than the abstraction, indicating that groundwater will remain sustainable as the primary source of water supply for the residents. In conclusion, the volumetric budget for the three scenarios shows that the aquifer has sufficient water supply to be used by the population despite the effects of climate change and population growth. Despite the availability of adequate water supply from the aquifer, there is a need for an effective and sustainable use of water from the aquifer, especially in the face of climate change and population increase.