Review: Approaches to groundwater exploration and resource evaluation in the crystalline basement aquifers of Zimbabwe

Abstract

Assessment of the groundwater potential of crystalline basement aquifers is challenging. These systems can be highly spatially variable, as indicated by the drilling of numerous dry boreholes and seasonal variation in discharge rates. This paper reviews methodologies applied for the evaluation of groundwater occurrence and yield estimation in the crystalline basement aquifers of Zimbabwe. These aquifers underlie much of the country and are described in terms of low yield owing to low recharge potential in the semiarid climate. In such regions, exploitable groundwater forms a strategic supply of potable water used to meet the socio-economic needs of the local population. Case studies are used to show how remote sensing and geophysical methods are integrated to improve borehole success rates in the basement aquifers of Zimbabwe. Potential threats to groundwater resources and quality within crystalline basement aquifers are discussed. It can be concluded that major issues remain to be addressed if sustainable use of the water resources of crystalline basement aquifers in Zimbabwe is to be achieved, especially with respect to borehole-siting approaches and prevention of groundwater contamination. The key recommendation is to address the paucity of primary groundwater monitoring data within the crystalline basement aquifers at the national level, thereby creating a technical groundwater management framework.