Devil's Gate Sediment Clearance Starts in June

County engineers delivered an update on the clearing of debris from Devil's Gate Dam at a Crescenta Valley Community Association meeting on Wednesday May 25, 2011 in La Crescenta.

The plan is to haul 25,000 cubic yards of dirt out of the Hahamongna Watershed Park starting June 17 and ending Aug. 15. Forty trucks will haul dirt and debris on weekdays from 7:30 a.m. to 4 p.m. Each truck will make four trips to and from the site per day and holds as much as 10 cubic yards.

The preferred route uses Windsor Avenue and Arroyo Boulevard in Altadena, said Public Works Department engineer Grace Yu. There are "wide enough roads ... [on Windsor] ... for trucks of the size we have now, and there will be minimal impact to residents and recreational users of the reservoir."

See a map of the preferred route and the entire presentation in the attachments above.

In all, the operation will involve water trucks, haul trucks with tarps, metal shaker plates, street sweepers, flagmen directing trucks along the haul route and an on-site supervisor.

"There is a possibility that we may not need to haul on public roads," Public Works engineer Keith Tang said Thursday. "In that case, we would opt to use off-road dump trucks of slightly larger capacity in order to further cut down on the hauling duration."

Tang said street-legal hauling vehicles are equivalent in size to a Peterbilt 10-yard-capacity dump truck.

Trucks will deposit organic Devil's Gate sediment at the Scholl Canyon Landfill, which is on North Figueroa Street in Glendale. Inorganic matter will go to the Manning Pit Sediment Placement Site in Irwindale.

In March the county Board of Supervisors voted to go ahead with an environmental impact study, a two-year process that includes "interim operational measures [to] maintain, restore and rehabilitate Devil's Gate Dam," said Yu. "The project will satisfy safety requirements we received from the state Water Resources Department."

Yu said this summer's project also involves fixing parts of the dam in disrepair, and that the last major renovation to the dam occurred in the mid-1990s.

A meeting on the county's Sediment Management Strategic Plan will take place June 29, 2:30 p.m. at the Public Works building, 900 S. Fremont Ave. in Alhambra.