Environmental groups that have long pushed to bring down a huge Colorado River dam along the Arizona-Utah border are suing the federal government.
They say in a lawsuit filed Tuesday in U.S. District Court in Arizona that the U.S. Bureau of Reclamation ignored climate science when approving a 20-year operating plan for Glen Canyon Dam. The dam holds back Lake Powell, one of the largest man-made reservoirs in the country.
Powell and Lake Mead are key to delivering Colorado River water to millions in the southwestern states.
Save the Colorado, the Center for Biological Diversity and Living Rivers want the plan redone and the removal of the dam listed as an option.
The Bureau of Reclamation has said that option wouldn't comply with water delivery requirements or other federal regulations.