Well, in California they could build additional reservoirs in the Northern part of the state to hold water that currently is far in excess of what they have the capacity to store, and goes into the Pacific as a result. It's an anti-growth state, and attempts to look at building more reservoirs has been shot down due to protest from environmentalists. For example, the push to build the Sites reservoir started over a dozen years ago, and has gone nowhere: https://norcalwater.org/efficient-water-management/sites-reservoir/

In central California, there are underground storage basins. The concern is that this has been possible only through Saudi investment.

But whether doing this for continued irrigation of crops makes sense, I'm not the expert to say that. I suspect some areas, particularly those using water from the Colorado rivers, will see less agriculture.

In the Great Plains, there is a minimal amount of aquifer recharge happening. There's potential for a canal (with a lot of pumping), to move water from where there's way more than enough to where they draw from the aquifers.

I've no idea what happens next with that. The current political climate would rather have us learn to eat the bugs than to see water resources go to increasing production for us meat eaters.