If L.A. County Department of Public Works officials can procure the necessary permits by late-July, they expect work can begin on the Devil’s Gate Reservoir Sediment Removal and Management Project in October, according to George De La O, a senior civil engineer with the Watershed Management Division.
Work to remove 1.7 million cubic yards of sediment — reduced from 2.4 million cubic yards last year by the L.A. County Board of Supervisors — over the course of four years, hinges on four key permits from the California Department of Fish and Wildlife, Regional Water Quality Control Board and Army Corps of Engineers, De La O said Tuesday at a public informational session at the L.A. River Center and Gardens.
The project’s initial excavation area will be 64 acres, he said, bordered by slopes where vegetation can grow.
Once the permits are granted, the department can hire contractors to do the work of hauling as much as 800,000 cubic yards (but more likely to be 500,000) of sediment per year from the Hahamongna Watershed area behind Devil’s Gate Dam to locations in Sun Valley or Irwindale. The contract, he said, will be for the total removal of 2 million cubic yards and to cover any potential sediment that could come down from the mountains during the duration of the project.
“We get questions, ‘Why the shape?’ or ‘Why the need for the extent?’” said De La O, who frequents the area as a member of the Pasadena Pacers running club. “There’s a certain capacity that we’re trying to get, and after the Station Fire in 2009, when we got 1.3 million cubic yards coming down into the reservoir, we’re really hoping to get more out.
“We have 650 parcels downstream on the Arroyo Seco that could be flooded, 447 residences and businesses, plus we have the freeway and local roads that could be impacted by a large flood,” he added.
“We’re concerned about something like what happened in Santa Barbara when we had those mudslides … and you had multiple deaths and property damage. We hope it never gets to that point here, and we’re really hoping that the regulatory agencies can see that and work with us to expedite those permits.
“This isn’t just that we want to clean out the reservoir because we like our bed made and our room clean, this is because it’s needed for flood protection.”
But Tim Brick, managing director of the Arroyo Seco Foundation, said he continues to have concerns about the scope of the project.
“The supervisors instructed it to be reduced by 30%, and that was a big accomplishment, but that needs to be translated into not just reducing the overall size, but reducing the impact of the project,” said Brick, whose organization has teamed with the Pasadena Audubon Society to file a second lawsuit to alter the project. “They’re still planning to use the same number of trucks, the same dirty diesel trucks and to destroy the same amount of habitat.”
De La O said the project will require 300-400 trips per day by trucks required to meet 2010 Environmental Protection Agency emission standards, and that those haulers will use a new to-be-built access road to avoid residential areas.
The project — nicknamed “The Big Dig” by some — will run from October through January 2019 for the vegetation removal to avoid bird-nesting season, De La O said. Then the sediment excavation will be conducted annually beginning in 2019, from April 15 through Nov. 30, weather permitting.
Trucks will queue up exclusively in the reservoir. During the school year, the hauling trucks will exit and enter the 210 freeway east of the reservoir via Windsor Avenue from 7-10 a.m. After 10 a.m., they’ll exit on Windsor but will use Berkshire Place to enter the freeway. (Caltrans has informed the Department of Public Works that it will not be working on ramps being used for the sediment removal.)
During the summer months when there is less school-related traffic, trucks exclusively will use Berkshire, De La O said.
No work will be done on weekends, holidays or when a special weekday event is happening at the Rose Bowl. The project will affect some of the trails in the vicinity, but the goal is for many to remain accessible, especially after work hours, he said.
When the project is completed, department officials have said they plan to institute a regular maintenance schedule. That could help to remove some 10,000 cubic yards per year.
“By doing it every year, we hope to avoid having to do such large projects where you have so many trucks,” De La O said. “You don’t want your garden to grow a bunch of weeds and then two years later say, ‘OK, now I’m ready.’ Your weeds will be [so] tall. So we’re just going to try to stay on top of it.”
The permitting process was slowed by the lawsuit, which resulted in some court-ordered modifications. Then, when county supervisors agreed to reduce the amount of sediment that could be removed, it meant Public Works engineers had to recalculate many aspects of the plan.
Now, De La O said, they hope to advertise the project within two weeks — and to then to receive permits in time to select a contractor to begin working this year.
“I find it ironic that we’re eight years into this process and they’re still trying to get their permits,” Brick said. “They were declaring this an emergency in 2010 and here we are in 2018 and they’re still working on permits.”
A couple of those permits relate to wildlife management, according to De La O, who said the Public Works Department plans to create wetland spaces in addition to enacting a 1-to-1 biological mitigation plan.
Brick said he finds the mitigation ratio, approved by a judge and county supervisors, insufficient.
“Usually mitigation plans are 2-to-1 or even 5-to-1,” Brick said. “If you’re replacing large willow trees with little willow saplings, it’s going to take a long time for those saplings to grow in and have the same impact that the current habitat has.
“We’re not trying to stop the project,” he added. “We’re just trying to reduce the impacts of the project.”