Case study note : groundwater residence times for rural groundwater supplies across different climate zones, West Africa

In 2010 the Department for International Development (DFID) commissioned a BGS-led team to undertake a one-year study aimed to improve understanding of the resilience of groundwater in Africa to climate change and links to livelihoods. As part of this project, the research team undertook hydrogeological field studies in West and East Africa, examined the linkages between water use and household economy, and developed an aquifer resilience map for Africa using existing hydrological maps and data. This is one of a series of technical notes which describes the studies carried by the research team under this project. This report describes the methodology, and results of the West Africa hydrogeological case study, undertaken within the one-year project. Groundwater residence times were assessed in both high and low storage aquifers across 4 different climate zones in a sampling transect from southern Nigeria to central Mali. Groundwater residence times were assessed through the use of multiple tracers: chlorofluorocarbons (CFCs), sulphur hexafluoride (SF6) and tritium (3H/3He). The purpose of the case study was to identify how vulnerable rural water supplies may be to climate change.