The Los Angeles County Department of Public Works will start work in July to remove 25,000 cubic yards of sediment from the basin behind Devil’s Gate Dam in Hahamongna Watershed Park.
The project is a stopgap measure to prevent valves and other dam works from becoming clogged this coming winter while the county studies options for the eventual removal of roughly 1.5 million cubic yards of mud and debris, most of it deposited after the August 2009 Station fire.
Excavation work, which could begin as early as July 5, would be limited to within about 100 feet of the face of the dam — leaving all wooded areas in the basin intact and eliminating the need for dirt-hauling trucks to pass through La Cañada Flintridge, said Chris Stone, assistant deputy director of Public Works’ Water Resources Division.
“We need to remove sediment that’s accumulated around intake structures to make sure they remain operational over the next one or two winters while we pursue [a study] for the larger project. If we couldn’t operate the valves, we could no longer discharge water downstream, and then it could build up and go over the stow-way” — flooding unchecked into areas below the dam, Stone said.