While generally I don't like the idea of water desalination (I'm a fan of learning how to make the most of what's available instead of forcing the system to work for you) I recognize that at least in the short term it may become a necessary part of life around the world. To that end, why not try to make this process as benign as possible?
I found a company, Water Standard
, who is trying to do exactly that. Their idea is to get a tanker-type ship, have it sweep through the sea and return to port loaded with freshwater. The advantage of this approach is that instead of a stationary desalination plant which would cause a considerable portion of a coastline to experience extremely salty conditions, the Water Standard method spreads the effect over a much wider area, helping to minimize the impact such activities have on local ecosystems. This, along with the mobility of the system in the even of an emergency, makes it a very interesting approach.