Cappaert v. United States
United States Supreme Court
426 U.S. 128 (1976)
President Truman designated Devil's Hole, a Nevada limestone cavern with a pool containing unique desert fish, as a national monument under the Antiquities Act because of its scientific importance. The Cappaerts (defendants), ranchers nearby, began pumping groundwater from a shared underground basin 2.5 miles away starting in 1968, which lowered the pool's water level; when the federal government (plaintiff) objected to the Cappaerts' request to expand their state-permitted water use, the Nevada state engineer sided with the Cappaerts anyway. The government sued for an injunction, and the district court, finding the president's proclamation intended to reserve the pool's water, granted it; the court of appeals affirmed, and the Cappaerts and intervening State of Nevada sought Supreme Court review.
Whether, under public land law, the federal government retains an implied right to unappropriated water located on land that is reserved for a federal purpose.