CALIFORNIA — Christopher Abela, a civil engineer with the U.S. Army Corps of Engineers Sacramento District ascends a climbing rope during an inspection of the tainter gates at New Hogan Dam near Valley Springs, Calif., April 10, 2012. Tainter gates are a type of flood gate used in dams to control water flow. New Hogan Dam reduces flood risk to the city of Stockton and stores water used for irrigation, drinking and hydroelectric power.