Geophysical exploration for groundwater in limestone aquifers of the Republic of Zambia

Seismic refraction and geoelectrical depth soundings were employed in Lusaka District of Zambia. Another survey was conducted in Kabwe District using resistivity mapping and depth sounding techniques. The purpose of these surveys was to evaluate the effectiveness of the methods in locating potable groundwater. Whereas the seismic method was re¬stricted in use to areas with no thick soil cover, it was found that resistivity mapping and depth soundings using the Schlumberger array can localize and partially determine the depth of fractured water-bearing limestone. The low resis¬tivity zones appeared connected in some areas but in other regions the low zones were isolated.Whereas it was generally believed that Kabwe limestone was impermeable at depths of 60 metres, wells drilled to depths in excess of 100 metres based on the results of this study gave improved yields as high as 150%.