In this February 22, 2005, file photo, with the North Rim in the background, tourists hike along the South Rim of the Grand Canyon in Grand Canyon, Ariz. National Park officials plan to replace much of the decades-old and problem-plagued pipeline that plunges down into the canyon and backs up the other side to supply water to South Rim hotels, campgrounds, and other facilities at the northern Arizona park. (Photo by Rick Hossman/AP Photo)
