To build on what Spindok said -
The real expertise that the Israelis can furnish isn’t so much in desalination (which can be acquired from many sources), but low-water agriculture. In an ideal world, the Syrians would be learning from the Israelis how to farm using less water. Judging from what the Gazans did with the greenhouses that were furnished to them free of charge, that doesn’t seem likely.
There’s a separate but related issue with the Dead Sea, and Israel, Jordan, and the PA are working cooperatively to deal with that. It’s not as simple as it appears, because adding sea water will upset the unique mineral composition of the Dead Sea, so ironically, the water to be added will have to be desalinated.
In the long run, the entire region is going to have to both conserve, and desalinate more. This will probably mean that Israel will have to either expand Dimona, or build a second nuke power plant. The alternative is more coal. No matter what they do, somebody’s going to object. So as always, Israel will ignore the objections, and do what she has to.
