One of the things being done in California currently is mapping all of these water deposits.
New desalination technology, has caused some rethinking.
Some Central Valley Aquifers are only slightly saline so could be made fit for farming at far less cost than ocean water - plus this water already lies below farming areas.
As a result these slightly-saline aquifers will probably no longer be available to oil drillers to discharge saline water pumped up with the crude oil and gas. Drilling operation using them will have to choose a different aquifer at a different depth, or install a pipeline to carry the brine to an injection well in an area with a highly saline aquifer.
Subsidence from ground water depletion was one of the reasons behind the California Aqueduct. Palm Springs paid for a lot of the project, and continues to pay annual costs.
Los Angeles receives the water Palm Springs pays for and some coastal cities have been using their allocation to refill their aquifers they depleted in previous years, which was leading to salt water intrusion.
Palm Springs, with no connection to the aqueduct they paid for, receives an equal amount of water from the nearby Colorado River aqueduct which Los Angeles built between 1933 and 1938 to bring water to Los Angeles. Palm Springs injects all of this water into their aquifer.
But Colorado River water is slightly more saline than the existing aquifer, so the Indian Tribe who own half of the land there are suing to have the Palms Springs water authority use RO to bring down the salinity of the river water to that of the aquifer, and I'm sure they'll win that lawsuit shortly.
We've run out of other people's Social Security taxes needed to subsidize our low income tax rates.
