Environmental indicators of recharge to basement aquifers of Tanzania

One of the main uncertainties surrounding the impact of climate change in
Africa is its effect on water supplies. Adding to this uncertainty is a lack of
information on recharge to the weathered basement aquifers and how these
aquifers respond to rainfall and abstraction.
Residence time indicators (such as CFCs) which can indicate the amount of
modern recharge in abstracted groundwater, can be a helpful first step in
identifying whether active recharge is occurring. Simple chloride balance
techniques are also useful to provide an indication of the proportion of
recharge. We report the results of using these environmental indicators in
the Singida area of Central Tanzania as part of a wider study of groundwater
chemistry in the basement aquifers.