Visitors stand atop newly dredged river sand at the

Visitors stand atop newly dredged river sand at the Antioch Dunes National Wildlife Refuge in Antioch, Calif., Nov. 9, 2013, the result of a unique partnership among the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers Sacramento District and the Port of Stockton. The sand – dredged from the Stockton Deep Water Ship Channel to ensure navigability – will help restore the Antioch Dunes ecosystem, creating habitat on the refuge for such endangered species as the Lange’s metalmark butterfly, the Antioch Dunes Evening Primrose and the Contra Costa Wallflower.