Word of warning....many years ago the late JC and I had been rock climbing down Paradise Valley south of Livingston. Hot day, crossed a small creek on the way back to the pick-up, stopped for a nice drink. Next day we were both in the Emergency Room with really bad cramps, diarrhea and vomiting. Giardia. About 10 days later we went back to the creek and hiked up-stream because we really wanted to know. In the creek a large, very bloated, very dead, extremely smelly cow. From then on we always carried water or GatorAid in the truck.