Interim Devil’s Gate Plan to Remove 3,000 Cubic Yards

Before the controversial Devil’s Gate Reservoir Sediment Removal and Management Project begins in earnest, the County of Los Angeles Department of Public Works was set to begin interim measures meant to reduce the potential impact of debris on flood control during upcoming storm seasons.
The immediate work is anticipated to last four weeks. During that time, about 3,000 cubic yards of sediment will be removed from behind Devil’s Gate Dam.
According to a release from the Department of Public Works, the sediment is being transported to Johnson Field in Pasadena, where it will remain temporarily. Green waste will be hauled to Scholl Canyon Landfill in Glendale at a rate of no more than 10 trucks per day to avoid impacts to the neighborhood along the Windsor Avenue haul route.
A biologist will be onsite during the ongoing work and no live trees are to be removed, officials said.
The larger project — in which 2.4 million cubic yards of sediment are to be removed over a span of three to five years — is expected to begin after the construction contract is awarded early next year. The specific timing and how much sediment is removed in 2017 will depend on when permits are issued.
When the project was introduced in 2013, area residents expressed concerns about increased truck traffic, pollution and potential harm to wildlife in Hahamongna Watershed Park. In response, officials modified the plan.
In an address to the La Cañada Flintridge City Council in June, principal engineer Keith Lilley reported that less sediment than the initially anticipated 4 million cubic yards will be removed. The update also calls for a 71-acre footprint, reduced from the original proposal of 120 acres.
Also, Lilley said the 400 truck trips per day along LCF streets near the worksite will be made by only low-emission trucks (or those meeting 2007 emission standards). Lilley also told LCF council members that about 70 acres of habitat will be restored, about 50 of which will be perpetually maintained.
He described a future of smaller sediment removal projects such as the ongoing work. The massive sediment removal, he said, was made necessary by the 1.3 million cubic yards of sediment that entered the reservoir following the Station Fire in 2009.
“After the project, every year we’re going to come in and remove that sediment,” he said in June. “We won’t be in this position again, where we’re put over the edge by a large sediment inflow. This will allow us to manage annual smaller amounts of sediment and not go through another major sediment project like this in the future.”
For information, visit or contact Steve Sheridan of Public Works Flood Maintenance Division at (626) 445-7630.

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