National groundwater recharge assessment under climate change
This study investigates replenishment of groundwaters and how climate change might alter this in the future.
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This study investigates replenishment of groundwaters and how climate change might alter this in the future. Around a third of public drinking water supplies come from groundwater and, in parts of the country, this proportion is far higher. Potential recharge is the water that percolates down from the base of the soil zone and has the potential to recharge groundwater aquifers, depending upon the properties of the underlying geology. Groundwater recharge is very difficult to measure directly and is often estimated using models. To determine the amount of groundwater that can be abstracted and used for water supply, it is first necessary to understand how much potential recharge is available to replenish the underlying aquifers.
The study found very little coherence in modelled potential recharge between different climate models during the 2050s. However, by the 2080s there is much more consistency in the recharge signal and there is evidence of a shortening of the recharge season from between 5 and 7 months to 3 to 4 months in future. The total volumes of annual potential recharge remain broadly the same between historic and future scenarios.
Understanding these changes will help people involved in the management of water resources develop management options to ensure the resilience of future water supplies.
The full research report can be accessed on the NERC Open Research Archive from 9am on 29 August 2019.