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County to remove sediment from Devil's Gate Dam as interim measure





<b>August 22, 2014</b> - While the public anxiously awaits LA County's Big Dig Plan for sediment accumulated behind Devil's Gate Dam in Hahamngna Watershed Parks, the County announces small-scale sediment removal plan for October.


By Lauren Gold


Pasadena Star-News


PASADENA >> Trucks will remove 5,000 cubic yards of sediment from behind Devil’s Gate Dam this October as an interim measure while the Los Angeles County Department of Public Works studies a larger sediment removal plan.

County officials said the project will begin Oct. 6 and be completed in about a month. The sediment will be temporarily dumped at Johnson Field and green waste will be taken to Scholl Canyon Landfill. County Public Works spokesman Kerjon Lee said the department has conducted minor sediment removal for the last three years as a way to ensure public safety.

“Removing this 5,000 cubic yards will ensure our ability to operate the dam this storm season,” Lee said. “It’s certainly not our intention to be alarmist when we talk about the need for removal but there is a significant increase of risk with the reservoir having the additional sediment in it.”

The county is due to release a final environmental report on the much larger sediment removal plan before the end of the year. The plan deals with excess settlement that has built up behind the dam since the last removal in 1994. The proposed project options, one of which involves removing 4 million cubic yards of sediment, created a fire storm among residents, environmental advocacy groups and city officials when the draft report was released last year.

In response, the city council appointed a group of residents and experts to draft an alternative that more fit the needs of the city. The council approved that plan in May.

City Manager Michael Beck said the city has had meetings with the county officials since May about the new proposal.

“We are continuing to have discussions between our public works staff and the county public works staff to see if we can get the preferred alternative to more closely match something that the county can support and that the city can support,” Beck said. “The meetings have been going well, very good sort of dialogue and understanding.”

Locals said they are generally supportive of the interim sediment removal, and are more focused on the county’s bigger project.

“It’s only 5,000 cubic yards, and that’s really a very small amount compared to what they are talking about doing, they are talking about doing as much as 4 million,” said Tim Brick, of the Arroyo Seco Foundation. “We don’t have any trouble with them taking immediate steps to make sure that the dam valves are operating effectively. And from our read of it, it seems they are trying to be responsive to truck issues and such.”

Many local environmental groups raised concerns that some of the proposals in the county’s draft environmental report would be harmful to the treasured natural resources of the Hahamongna Watershed Park and that the trucks required to remove a large amount of sediment would be harmful to the surrounding neighborhoods.

“I’m very anxious about the EIR,” said Laura Garrett, conservation chairwoman for the Pasadena Audubon Society. “I’m worried about what we are going to see at the end of the year when the final EIR is released.”

The sediment removal project is scheduled to begin in 2015 after final approval from the Los Angeles County Board of Supervisors, and will last for at least five years.

For more information on the Devil’s Gate Reservoir sediment removal, visit

Lauren Gold
Reach the author at or follow Lauren on Twitter: @laurenkgold.




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