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County Public Works officials reach out about coming work around Devil’s Gate Dam

Engineers and employees from Los Angeles County Public Works Department use a pop-up van Saturday to
Los Angeles County Public Works employees use a pop-up van Saturday to reach out to recreational users of Devil’s Gate dam area and surrounding Arroyo Seco about a four-year sediment removal project expected to start in late October.
(Sara Cardine)

A four-year effort to remove 1.7 million cubic yards of sediment from behind Devil’s Gate Dam in the Arroyo Seco will begin this month with restoration of a wildlife habitat area, Los Angeles County Public Works Department officials announced last week.

In the Oct. 5 news release the department stated the first phase of the project will center on a 70-plus acre restoration area, where invasive plant species will be removed and replaced with native plants to make the sloped area around the dig site more habitable for wildlife.

Soon after that work begins, access roads to and from the nearly 50-acre hauling site will be built to reduce traffic on nearby streets in Altadena and La Cañada and accommodate an estimated 425 round-trip daily truck trips. The removal of trees and brush in the project area could start as early as November, engineers confirmed.

“The vegetation removal will likely start toward the end of November or December,” said county engineer George De La O. “That will be one of the biggest changes.”


De La O and colleagues hit the streets Saturday, setting up a Public Works education and outreach van on an access road by Devil’s Gate Dam to reach out to recreational users of the area about some of the work they might see and anticipated temporary trail closures.

County engineer George De La O explains to a cyclist near Devil's Gate Dam on Saturday where access roads will be built to accommodate sediment-hauling trucks in a four-year removal project,
(Photo by Sara Cardine)

“The goal for today is to get to people who use the area recreationally,” department spokesman Kerjon Lee said Saturday, as hikers, bicyclists and parents pushing strollers stopped by to learn more. “People know even more than we knew about the history of the dam and the flooding that’s happened — we’re learning as much as we’re teaching.”

The flood-prevention project has been debated in public forums since first proposed following the 2009 Station fire, which was a contributing factor to the buildup of debris behind the concrete dam. A 2014 lawsuit by Pasadena environmentalists stalled the work and successfully reduced its original scope by 700,000 cubic acres.


Sediment removal is expected to begin next April, with trucks running Monday through Friday, from 7 a.m. to 3:30 p.m. Hauling will take place each year from April to October, or November, through 2022.

A 24-hour hotline, (800) 675-4357, has been established for the project.

Twitter: @SaraCardine