Major John Wesley Powell led scientific exploration parties down the Green and Colorado Rivers in 1869 and in 1871-72. Years later he became a leader in government science programs, headed the U.S. Geological Survey and the Bureau of American Ethnology, and advocated enlightened land and water conservation policies that resulted in the passage of the Reclamation Act of 1902. In commemoration of his courage, his wisdom, and his years of public service, the reservoir behind Glen Canyon Dam was named Lake Powell.