If you're open to naked theft as so much of the US and world is today, that's going to have long term consequences you won't like. Water rights are a real thing in US jurisprudence, their abrogation by Federal judges, especially I assume in the 9th Circuit doesn't make them any less so. As I said, "if the rule of law still means something...."
So, uh, I don't think that property rights should extend to a large share of all water produced in the state in perpetuity. It's been bad law from the beginning and we should not be stuck with it forever. Fortunately, California never really went down this path.
In California, the State Water Resources Control Board issues water right permits, and can modify them. They have a "senior interest" in property law to the individual holders of these permits.
Of course, snatching back water rights isn't necessary for sanity to prevail. All that has to happen is the state needs to start moving to charging a true market cost for agricultural water use, and this is well within the state's taxation powers. One of the most commonly agreed legitimate uses of governmental power is to allocate the cost of externalities.