Groundwater resources assessment in the Densu Basin: A review

Study region: Densu River Basin in Ghana, West Africa. Study focus: This paper reviews aquifers and groundwater resources in the Densu River Basin based on several past studies which adopted hydrochemical, numerical modelling, geostatistical techniques, and several other conventional methods with particular focus on the hydrogeological and hydrochemical characteristics, general water quality and quantity challenges, and the projections thereof. New hydrological insights: Groundwater recharge was revealed to far exceed the abstraction and offer great potential for other uses. However, the recharge rate is at the risk of diminishing due to climate change threats such as falling runoff and rainfall amounts, rising atmospheric temperatures, and population growth. The groundwater is generally of acceptable quality for domestic, agricultural and industrial purposes. The hydrochemistry of the groundwater is principally controlled by silicate weathering, ion exchange and sea water intrusion. Groundwater contamination due to domestic waste discharge, mining and agricultural activities also feature significantly in the basin. The emerging issues identified in this review include rising water demands, impacts of climate change on groundwater resources, anthropogenic effects on groundwater quality and inadequate knowledge of the underlying aquifers. Integrated hydrogeological assessment of the basin conducted in a holistic manner will therefore be necessary to properly understand the aquifers and groundwater resources in the basin for informed water management decisions.