Report on ‘Big Dig’ Project Pulled From Public Safety Committee Meeting

A report on sediment removal from Devil’s Gate dam which was to go before the Public Safety Committee Wednesday has been removed from the agenda.

The report said that sediment removal resumed in Hahamongna Watershed Park Monday, and that this time, according to the L.A. County Department of Public Works, steps are being taken to lessen the negative impacts on neighbors living near the project.

The report also said the department has upgraded its 2021 sediment hauling fleet in an effort to improve truck emissions performance.

Other steps taken include pre-watering sediment prior to the loading of the trucks, watering all loaded trucks before they leave the reservoir to control material from blowing out of truck beds, maintaining tire wash stations to remove dirt from tires and undercarriages of trucks, and using street sweepers to continuously sweep paved surfaces, including the truck access ramp and the local sediment hauling routes.

Ninety-five Trucks are scheduled to be used to make a maximum of 425 roundtrips daily, according to a report in the City Council’s Public Safety Committee (PSC).

Hauling hours are from 7 a.m. to 3:30 p.m. Monday through Friday.

The committee had been scheduled to discuss the project at 4 p.m. Wednesday.

“L.A. County Public Works listened to and worked with community stakeholders and implemented mitigation measures to further reduce the impacts of the project on the communities surrounding Devil’s Gate Reservoir. We have implemented the measures below and will continue to work with the communities to implement other enhancements as needed,” according to a prepared statement issued prior to the removal of the report from the Committee agenda.

The county Public Works Department is removing 1.7 million cubic yards of sediment from the reservoir immediately behind the 100-year old dam.
According to a report in the PSC agenda, 532 cubic yards of sediment were removed in 112 hauling days last year. In total, 980,000 cubic yards of sediment hav been hauled away.

The project is scheduled to be completed ahead of fall 2022 and could be finished in November, according to the staff report.

In addition to providing flood relief to communities that have endured more than a decade of elevated flood risk along the Arroyo Seco, the project will establish a permanent stormwater maintenance area that allows for the creation of 70 acres of enhanced habitat and recreational opportunities.

In correspondence to a joint meeting between the City Council and Supervisor Kathryn Barger, local residents told Barger that there is still a problem with trucks idling as they wait to enter Hahamongna Watershed Park to remove sediment as part of the local Devil’s Gate Restoration Project, also known as “The Big Dig.”

Dust pollution is also an ongoing problem.

“Many diesel trucks arrived at the project at the first hour of each project day resulting in a number of diesel trucks that were delayed and were idling for long periods of time,” according to resident Nina Chomsky.

Chomsky said some of the trucks were idling for 25 to 30 minutes, instead of the expected four minutes laid out in the environmental impact report.

“Idling must be reduced, or better eliminated, for the remainder of the project,” Chomsky wrote to the City Council.

Barger told the council that she drives by the area constantly and takes pictures and sends them to the county’s public works department.

“I am closely monitoring this. The bad news is when I see a truck without a tarp or idling I will be the first one to bring it to the attention of Public Works,” Barger said.

The project is a four-year effort to increase flood protection for communities downstream of Devil’s Gate Dam and restore habitat within a popular section of the Arroyo Seco Watershed.

According to Barger, the project is ahead of schedule and native plants are already being replanted.

Devil’s Gate is the oldest dam constructed by the L.A. County Flood Control District, providing flood protection for Pasadena, South Pasadena and Los Angeles.

A large amount of sediment had not been removed from Devil’s Gate since 1994 when workers hauled out 160,000 cubic yards. The Station Fire in 2009 then dumped a million cubic yards of soil and debris into the basin.

The Board of Supervisors voted on July 7 to approve a settlement between L.A. County, the Arroyo Seco Foundation (ASF) and the Pasadena Audubon Society (PAS) that reduced the negative impacts of the project on endangered bird species within the area.

There was no immediate explanation of why the item was pulled from the agenda.