Controlled water supply it is. Israel controls it. Who and where it goes will be determined by Israel. Let's say it's one hour per day, they'll be standing in line fighting over it like dogs over a bone. Collective punishment, by that you must mean the Kassams bombardments of Sderot or the homicide bombings of a full load of bus passengers or all the diners eating peacefully in a restaurant. Collective punishment is in the eyes of the beholder.
Egypt says verdict in Al-Jazeera case expected Saturday (AP)
from the article: U.S. lauds Israeli restraint in face of Qassam rocket attacks