Farmers in California are literally pumping the aquifers dry. There are already people who have had to abandon their homes because you can't just dig the wells deeper to hit water anymore.
>A frenzy of well drilling by California farmers leaves taps running dry
https://www.latimes.com/projects/california-farms-water-well...
Ground water is a limited public resource. Farmers do not have the right to pump the aquifers dry and render the area uninhabitable.
I would imagine that you could require a license to pump ground water in areas where the ground water level has already dropped dangerously low.
>Water rights east of the Mississippi work differently than water rights to the west. In the west, they are based on seniority.
That applies to water on top of the ground (lakes, rivers, streams), not the water under the ground.
Farmers in California were running out of water 100 years ago too, and people responded with massive engineering projects to regulate water throughout the year and move it from places that were at the time water-rich to places where more water would allow using the extremely fertile land with favorable weather for agriculture.
It’s not insane to consider doing the same again.
The idea that californias water projects only direct water downhill is invalid anyway - the California aqueduct flows uphill quite a lot, and over mountains.
https://en.m.wikipedia.org/wiki/Edmonston_Pumping_Plant is one of at least 5 pumping plants along the aqueduct.