RE: Keeping Meat Cool
If you're going to use a stream to cool meat, please put it in a garbage bag first. I have done this once. I recommend putting it in the stream in big garbage bags in shade in the heat of the day, IF NEEDED. Then take it out during the cool hours, out of the water AND out of the garbage bags. (It's generally a bad idea to put meat in garbage bags.)
I once put in my backstrap and tenderloin cuts in the water w/o protecting them, and returned in horror to find all the color leached out of the meat. It wassickening blond color. A few hours out of the water and the normal coloring came back.
Anyhow, the meat really doesn't have to be submerged, just a little flow of water underneath will do the trick. I put it more on the cool, mossy rocks with just a small percentage of the underside touching actual water.