|from Jackson and Kang|
While this is good news for California, the findings do not solve California’s water problems. First, much of the water is 1,000 - 3,000 feet or deeper below grade, so pumping it will be more expensive. Without proper management, tapping these deeper aquifers might also exacerbate the subsidence, the sinking of the land, that is has been happening throughout the Central Valley. Groundwater pumping from shallow aquifers has already caused some regions to drop by more than 75 feet. Secondly, groundwater salinity increases with depth and some of the deep aquifer water is as expected, higher in salt concentration than shallower groundwater, so desalination or other treatment will be necessary before it can be used for either drinking or irrigation for agriculture in the state.
The scientists used data from oil and gas production provided by the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR) that contained information on formation water salinity and total dissolved solids, TDS, from oil and gas pools and records of wells drilled to depths of a several thousand meters. A concern that the Stanford scientists point out is that oil and gas drilling activities are occurring directly into as much as 30 % of the sites where the deep groundwater resources are located. In Kern County near Bakersfield where much of California’s oil and gas industry is centered, one of every six oil and gas wells was drilled directly into freshwater aquifers. For potentially useable water, water that the U.S. Environmental Protection Agency deems drinkable if treated, the number was one in three.
As Dr. Jackson points out in the linked video, the oil and gas industry is the only industry that is allowed to inject chemicals directly into potential drinking water sources. The more we learn about the fate of these chemicals, the greater the concern. With California in its fifth year of drought and the growing need for water in California, we need to reconsider these practices. We need to better characterize and protect deep groundwater aquifers not only in California but in other parched regions where these water resources will be needed before too long.