Drinking Fountain?
From our Indian Garden campsite, we hiked 1.5 miles out to Plateau Point, on the edge of a cliff overlooking the river. We passed evidence of a water system going all the way out to the point, including this drinking fountain. It didn't work, of course. It turns out the water pipes are part of the trans-canyon water delivery system that supplies the entire South Rim with water from a spring on the north side of the canyon.