Binny, I totally understand where you're coming from, but the nature of the INT is that you sort of have to bend your mentality to fit it, not the other way around. It would be great if you could just travel the whole trail without having to rely on any outside assistance, but it's not really designed for you to "go it alone." In the Negev, water really is so scarce that it's best to err on the side of caution.
I wouldn't consider any stream in the Negev to be reliable, especially during the time you're planning on going. And even if you found water,
a) it probably wouldn't be that good to drink;
b) there likely wouldn't be enough available to give you what you needed;
c) even if there were, you'd be drinking it at the expense of animals that need the water to survive.
I mean, given the choice between a cache of bottled water and this:
[IMG]http://i248.photobucket.com/albums/gg187/redharen/INTDP%20Southern%20Negev%20Hike%202008/IMG_0017.jpg[/IMG]
wouldn't you rather drink some bottled water?