Contractors for the Sacramento District prepare for concrete placements at the Folsom Dam auxiliary spillway project April 29, 2015, in Folsom, California. Preparations include survey work, surface cleaning and installation of groundwater drainage systems (underneath black fabric in background). The U.S. Army Corps of Engineers Sacramento District, together with the U.S. Bureau of Reclamation and state and local partners, is building the spillway to reduce flood risk throughout the Sacramento region.