Also, if you don't want the detour into the Little Yosemite Valley campground, there are easy river access spots shortly after you leave the Nevada Fall restroom at the Mist trail/JMT junction. Just watch for when the trail gets near to the river, and get it there. If you go too far and get away from the river, you can still take the Little Yosemite Valley campground fork and fill up.
I'd be sure to have at LEAST a half gallon from there, after you've drank your fill. When we went up during a hot spell in late May, I used pretty close to a gallon including a bottle of Gatorade (for the whole hike from Happy Isles and back).
For the spring I'm thinking of, after you pass the 2 mile to Half Dome trail junction and get past the first zigzags (~10 min), look for a big downed tree/log on the left...one that might look inviting to sit on. It's just behind that log, and you can't see it from the trail. As others said, don't depend on anything past the Merced in this dry year. Even if you have water, if that spring is flowing you might want to stop; that icy cold water tasted absolutely wonderful on our way down.
Post Edited (07-27-07 14:15)
Gary
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