ABSTRACT
ABSTRACT: The groundwater resources of northeastern Ghana have been assessed based on the interpretation of existing hydrogeological and water quality data from 2458 boreholes drilled throughout the region between 1954 and 2004 for domestic water supply. Single parameter groundwater and hydrochemical maps were developed to show the spatial distribution of groundwater and the geochemical characteristics for the region. Groundwater occurrence in the area is largely influenced by rainfall, topography, overburden thickness and geology. Aquifers are discrete, localised and discontinuous and groundwater flow is controlled by fracture intensity and the degree of interconnections. The recorded data indicate an average success rate of approximately 65%. Borehole depths range from 28 to 60 m. Groundwater was encountered at a mean depth of 30 m (range 13-42 m), and static waterlevels stood at a mean depth of 8 m below ground level. Estimated yields of successful boreholes averaged 0.8 l/s and varied between 0.1 and 6 l/s, with higher yields occurring in the highly-fractured granitic and metamorphic rock areas. The total annual groundwater abstraction comprises approximately 74% of the total domestic water requirement of the region. Concentrations of nitrate, fluoride and manganese higher than WHO guideline levels were recorded in some boreholes in the Bongo, Bolgatanga and Kassena-Nankana districts.
