Groundwater recharge - replenishment above extraction rates - is linked to infrequent extreme precipitation events, reports work published online this week in Nature Climate Change. At present, intense rainfall is associated with negative socio-economic consequences, such as crop and property loss. However, these findings suggest these events could have a benefit, with groundwater becoming a vital future water resource as climate change depletes other water supplies.

Richard Taylor and colleagues examined a newly compiled 55-year record of groundwater-level observations in an aquifer in central Tanzania. They show that the highly episodic occurrence of recharge is a result of anomalously intense rainfall associated with major events of the dominant modes of tropical climate variability in the region. It is predicted that incidence of these events may increase in the future as model projections show a shift towards more intense monthly rainfall.