Driving on route 5 in California one sees the signs of conflict over water. It has been going on here for a long time. It is a battle the rest of the world will face in the coming years. As far as I can tell the issue in California remains unresolved. Even no action is an action; and there will be consequences.
An example of early planning is Valencia Spain where the water board dates from the 14th century and are tasked with the responsibility of regulating the water and it’s use in the region.