Characterisation and quality assessment of surface and groundwater in and around Lake Bosumtwi impact craton (Ghana)

Abstract

Conventional graphical methods have been used to classify water in Lake Bosumtwi and groundwater around the lake. The study also assessed the suitability of these water resources for agricultural use. Results indicate slightly acidic, moderately hard to very hard groundwater with alkaline earth concentrations exceeding alkali metals. In contrast, the lake water is alkaline, showing alkalis in excess over alkaline earth metals. Weak acids exceed strong acids in both lake/groundwater. Rock weathering largely controls groundwater and lake water chemical compositions, resulting mainly in Ca–Mg–HCO3 groundwater and Na–HCO3 lake water types. Thus, suggesting that there is no apparent incipient relationship, which benefits the primary aquifer system in terms of recharge. Water quality indices suggest groundwater of good to excellent quality for human consumption and other domestic use. An evaluation of lake/groundwater based on salinity, sodicity and bicarbonate hazard reveals that the groundwater is generally suitable for irrigation whiles the lake water is not suitable for irrigation. However, the lake water may be used in generous amounts on highly permeable soils and salt-tolerant crops under special soil and water management practices.