Scientists find ‘Water windfall’ beneath California’s Central Valley, making the state’s water supply three times larger than previously estimated

This is great news for an area suffering a prolonged drought, however accessing this water in a financially sensible way and safeguarding it from possible contamination from oil and gas activities will be challenging

This is great news for an area suffering a prolonged drought, however accessing this water in a financially sensible way and safeguarding it from possible contamination from oil and gas activities will be challenging

Groundwater withdrawals are increasing across the US, and particularly in California, due to the state’s growing population and prolonged drought. Stanford scientists focused their research on deep groundwater aquifers, believing they could be of use in the future and worth protecting them. According to their findings, in the Central Valley alone, estimates of fresh groundwater volumes can be increased almost threefold, and those of useable groundwater volumes fourfold for depths up to 3 km. However, some of these deep groundwater resources are vulnerable to contamination from oil, gas and other human activities. Their research was published earlier this week in the journal Proceedings of the National Academy of Sciences, showing the need to better characterize and protect deep groundwater aquifers. “What we are saying is that no one is monitoring deep aquifers. No one’s following them through time to see how and if the water quality is changing,” study co-author Mary Kang said. “We might need to use this water in a decade, so it’s definitely worth protecting.”

Up until now, it was thought that California's Central Valley had less than 1,000 km³ of water below it, because only groundwater within 300m of the surface was taken into account. Stanford scientists, analyzing data from more than 34,000 oil and gas wells in California, and for depths down to 3 km, estimated the reservoir’s water volume to 2,700 km³ - almost triple the initial estimations. Thanks to new technology, it is now possible to extract water from such depths, even though pumping it will be expensive, and some of the deepest water might be salty, so would need to be treated before use. Even worse, the newly found groundwater is already at risk of contamination from oil and gas extraction (around 30% of the supplies are close to drilling sites).

Source: Stanford News