Photo of Howard A. Hanson Dam, a U.S. Army Corps of Engineers dam, located near the headwaters of the Green River in King County. The dam is an earth and rockfill structure with inclined core drain and filters. Outlet works on the left bank consist of an approach channel, an intake structure providing upstream control, a 19-foot diameter horseshoe concrete-lined tunnel, a stilling basin, and an auxiliary 48-inch diameter bypass pipe.