Evaluating the Effect of Absolute and Barometric Pressures on Borehole Performance in Tolon and Wa West Districts of Northern Ghana

Abstract

Groundwater is a very important asset to the people of Northern Ghana where majority are farmers as its used for many domestic and agricultural activities. The research evaluated the effects of absolute and barometric pressures on water-table fluctuations of boreholes in Wa West and Tolon Districts of Northern Ghana. Pumping tests, absolute and barometric pressures were monitored using non-vented water level sensors for one year, from 2015-2016. The results of the research indicate that, the aquifer of the Kpaligung borehole is of Voltaian province while that of Baleofili is Granitoid intrusions. The yield of the Baleofili borehole is 1.8 m3/h (30 l/min), while that of the Kpaligung borehole yields 1.4 m3/h (23 l/min). Rainfall regime has considerable effects on Kpaligung and Baleofili boreholes` recharge and water-table fluctuation due to the effects of both absolute and barometric pressure throughout the year. The relationship between barometric pressure and water pressure for the Kpaligung borehole shows positive, but weak correlation value (0.2) that is, increase in barometric pressure leads to an increase in water level and vice versa. The Baleofili borehole shows an inverse relationship between barometric pressure and water level pressure with the coefficient of correlation being 0.5. The relationship between the changes in water level of the boreholes with the corresponding change in rainfall amount suggests that the groundwater recharge of the boreholes depends considerably on annual rainfall variation in the study areas considered.