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Arroyo Seco Foundation

News of the Arroyo


Bulldozers ready: Temporary dig planned behind Devil's Gate Dam in Pasadena





<b>September 14, 2017</b> - LA County Flood Control will begin an annual maintenance program at Devil's Gate Dam that will involve ten trucks a day and 4,000 cubic, less than 1% of the still pending Big Dig.


Steve Scauzillo


Pasadena Star-News


PASADENA >> Bulldozers will begin scooping sediment from behind Devil’s Gate Dam starting Friday as part of a temporary dig in the Hahamongna Watershed Park wilderness area, the county announced this week.

An interim project will remove 4,000 cubic yards of dead trees, muck and debris washed down from higher elevations from last winter’s storms, enough to reduce the potential of dangerous debris flows during the coming winter, according to the county.

“Dead tree branches and other vegetative matter will also be removed from the work area immediately in front of the dam,” the county’s Department of Public Works announced in a statement Wednesday.

The work is expected to take four weeks to complete, the county reported. Some material will be stored in the Upper Arroyo Seco at Johnson Field, after the county received permission from the city of Pasadena. The green waste will be hauled to Scholl Canyon Landfill near Glendale in dump trucks at a rate of about 10 per day for four weeks.

Public Works stressed that this is only a temporary measure and is not part of the larger sediment removal project approved by the county Board of Supervisors in 2014 that has been tied up in court over environmental concerns. The county wants to remove 2.4 million cubic yards of sediment, dirt and plants that would take five years using 425 trucks a day.

That project was dealt a blow in February when Superior Court Judge James Chalfant agreed in part with the Arroyo Seco Foundation and the Pasadena Audubon Society that the final environmental impact report was deficient in three areas.

The county has reworked portions of the environmental documents that challenged whether replacing wildlife habitat that will be destroyed on a 1 acre-for-1 acre ratio is satisfactory. The area is home to 206 bird species and the endangered least Bell’s vireo, a songbird on both federal and state endangered species lists. The county’s environmental analysis said there were only 50 bird species.

While the two plaintiffs oppose the main project as excessive, they see the interim cleanup behind Devil’s Gate Dam, about 1 percent of the planned main project, as a prudent approach to flood control.

“Ten trucks a day sounds a lot better than 425,” said Tim Brick, managing director of the Arroyo Seco Foundation. “Another comparison: 4,000 cubic yards as compared to 2.4 million. That is less than 1 percent of what they are talking about in the big dig.”

Brick said the two groups want to see regular maintenance involving small amounts of sediment removal instead of the much larger project that the groups contend will badly damage an area used for hiking, bird watching and education field trips.

“We’ve always encouraged ongoing maintenance at the dam. That is what we wish they were doing — removing some more every year,” Brick said.

Steve Scauzillo
Reach the author at or follow Steve on Twitter: @stevscaz.




Arroyo Seco Foundation, PO Box 91622, Pasadena, CA 91109-1622 (323) 405-7326