You could probably also do it without directly interacting with the farmers at all, by putting a water tax, similar to a carbon tax, on products that are produc

You could probably also do it without directly interacting with the farmers at all, by putting a water tax, similar to a carbon tax, on products that are produced in areas with non-abundant water resources. So, rice from Arkansas would remain the same price, but almonds from California might get a little more expensive. This could lead farmers to start making more rational choices with their water supplies out of their own self-interest, or investing in water-preserving technologies.