This case study explored the resilience of shallow groundwater supplies (borehole depth <50 m) to climate variability.
Boreholes of this depth are often the only sources that are operational during the dry season, and are widespread throughout Africa.
Download the Case Study NoteGroundwater was sampled from shallow groundwater supplies (<50 m deep) in West Africa comprising four study areas with different climates, from humid near Lagos in coastal Nigeria to semi-arid climate in Mali.
Each study area contained a weathered basement aquifer and a sandstone aquifer, and samples were taken from both.
Only shallow boreholes with handpumps were sampled at each location to minimise sampling bias.
Groundwater was sampled for:
These sampling techniques are a novel way of estimating groundwater residence time, and enabled useful results from one round of sampling — essential to the short (one year) research programme.
A short discussion was also held with village elders and representatives of the community at each sampling site to gather information about water use.
Fifty-six boreholes were sampled in total: seven in each aquifer type in each of the four climate zones.
The results of the case study demonstrated a high degree of resilience to climate change for hand pump supplies across the range of climate zones and aquifers sampled (mean annual rainfall 400–2000 mm):
Contact Dr Alan MacDonald or Dan Lapworth for further information