Heres why its dry.
During the gulf we attacked alot of water depots to starve of water to military bases and some civilian sectors that we knew miltary was stationed in. It was also devised that during the cold war cuting of water supplies to nuclear powerplants would force them to shut down the reactor. Disabaling but not Destroying electricity.
That was then. Theres no reason to hit water depots and pumping stations now since there is no real enemy base of opperations.
Our military is still sticking with the gulf war plan of attack.
Ask your self. How would you like to drink the same water you just used to defacte? Good movie.