Groundwater hydrochemistry evaluation in rural Botswana: A contribution to integrated water resources management

Abstract

Groundwater is one of the major sources of exploitation in arid and semi -arid regions. To protect this scarce resource information on its quality status over time is important. This paper examines the quality of groundwater from domestic water supply boreholes across rural Botswana. Ionic concentrations of K+, Na+, Ca2+, Mg2+, F-, Cl-, SO4 2-, HCO3
-, Fe3+, Mn-, and N. Parameters such as pH, total dissolved solids (TDS), and electrical conductance (EC) were correlated and their levels compared to international standards. Levels of various physico-chemical parameters were also analyzed for temporal trends for in the various districts across the country and those with significant trends were then contoured to determine areas at risk of groundwater contamination. Groundwater in rural Botswana is generally suitable for human consumption despite high levels of cations. Nevertheless, levels of Na+, Ca2+, EC and TDS are showing
increasing trends in some parts of the country highlighting the need for periodic monitoring of groundwater quality to isolate and possibly advise on discontinuation of polluted boreholes.

Key words: Groundwater, Rural, Physico-chemical, Water Resources, Botswana