Lake Powell is a reservoir on the Colorado River in Utah and Arizona, United States. It is a major vacation destination visited by approximately two million people every year. It holds 24,322,000 acre-feet of water when full, second in the United States to only Lake Mead - though Lake Mead has fallen below Lake Powell in size several times during the 21st century in terms of volume of water, depth and surface area.  Lake Powell was created by the flooding of Glen Canyon by the Glen Canyon Dam, which also led to the 1972 creation of Glen Canyon National Recreation Area, a popular summer destination of public land managed by the National Park Service. The reservoir is named for John Wesley Powell, a civil war veteran who explored the river via three wooden boats in 1869. It lies primarily in southern Utah, with a small portion in northern Arizona.  Lake Powell is a water storage facility for the Upper Basin states of the Colorado River Compact (Colorado, Utah, Wyoming and New Mexico). The Compact specifies that the Upper Basin states are to provide a minimum annual flow of 7,500,000 acre-feet to the Lower Basin states (Arizona, Nevada, and California).  According to US Geological Survey and the Bureau of Reclamation report, in addition to water loss, Lake Powell faced an average annual loss in storage capacity of about 33,270 acre-feet, or 11 billion gallons, per year between 1963 and 2018 because of sediments flowing in from the Colorado and San Juan rivers. Those settle at the bottom of the reservoir and decrease the total amount of water the reservoir can hold. Environmentalists have pushed to drain Lake Powell and restore Glen Canyon to its natural, free-flowing state.