President William Howard Taft set aside the bridge as a national monument in 1910. For many years it was one of the most isolated and hard-to-reach units of the National Park Service. However, in 1956 Congress passed an act authorizing the construction of Glen Canyon Dam. Suddenly Rainbow Bridge, which would be on the projected shoreline of the reservoir to be named Lake Powell, became controversial. The act decreed that barrier dams had to be built to keep the lake out of the monument, but the U.S. Court of Appeals ruled in 1973 that since Congress had repeatedly refused to appropriate funds for these barrier dams, that special provision of the act pertaining to them had been abrogated.
*Navajo Indians maintain that Rainbow Bridge figures prominently in their religion as a symbol of rainfall and fertility. The Navajos were unable to halt the rise of Lake Powell to the bridge, but the National Park Service agreed to prohibit "disrespectful" acts--such as swimming under the bridge.