Assessment of Groundwater Sustainability in the Bawku East Municipality of Ghana

The sustainability of groundwater, which is the major source of potable water due to its general superiority in terms of natural quality and reliability in the semi-arid Bawku municipality had been assessed quantitatively using data on 760 boreholes, 79 hand-dug wells (HDWs), 8 mechanized boreholes, and water quality analysis of 25 boreholes and 10 HDWs. Analysis of drill logs revealed the existence of granitoids and Birimian metavolcanics as the main geological formations hosting structurally controlled aquifers. The estimated current annual water demand and abstraction were 6.52×106 and 2.8×106 m3 respectively while the estimated annual recharge rate, permanent groundwater reserve and recoverable water reserve were 20.6×106 m3, 799.02×106 m3 and 319.61×106 m3 respectively. The study showed that the current groundwater abstraction constitute only 13.6% of annual groundwater recharge, 35.02% of permanent groundwater reserve and meets only 42.9% of groundwater demand leaving a deficit of about 57.1% (3.72×106m3/yr). Thus, aquifers meet current demand and have the capacity to be further developed to meet future needs sustainably. The observed gradual decrease in groundwater levels, annual rainfall figures and a corresponding increase in temperature (unfavourable climate change effects) coupled with the ever-increasing population may impact negatively on groundwater reserve in the near future if adaptive measures are not put in place. We recommend for further and more detailed studies including but limited to continuous monitoring of groundwater levels, yield, quality and isotopic studies of the resource in the municipality so as to ensure sustainable management to meet the socio-economic needs of the inhabitants.