This Colorado River dam feeds a 67-milelong canal system that irrigates the Grand Valley, as the valley of the Colorado River between Palisade and the Utah border is called. The first set of imported German rollers (the huge cylinders that control the flow at the top of the dam) lies at the bottom of the Atlantic Ocean, part of a cargo sunk by British warships during World War I. Graceful arches above the seven German-made roller gates support a bridge and four tile-roofed towers containing the mechanisms to raise and lower the rollers. The dam diverts water into irrigation canals cut through sandstone cliffs. The $4.5 million project, the third roller dam in the United States, was begun in 1909 by the Bureau of Reclamation, but a clash between Secretary of the Interior Richard Ballinger and conservationist Gifford Pinchot held up the project for years.