Sediment Removal Project Returning to Court for Hearing on June 25

Lawyers for the county and local preservationists opposing the size of a Devil’s Gate Dam sediment removal project will return to court for a hearing on June 25, Pasadena Now has learned.

The Flood Control District is currently in the early stages of removing 1.7 million cubic yards of sediment and debris that has accumulated in the dam’s reservoir — a project that could last four years and require daily hauling of up to 475 truckloads of dirt.

Settlement talks are ongoing.

According to LA County Public Works officials, the purpose of the project is to increase flood protection for communities downstream of Devil’s Gate Dam by removing 1.7 cubic yards of sediment.

County officials say the project will also restore habitat within a popular section of the Arroyo Seco Watershed.

Preservationists do not oppose the sediment removal, but are concerned about the size of the project and the pollution that will be caused by 450 truck trips into the Lower Arroyo everyday once the sediment removal begins.

“We filed this lawsuit to force the agency to manage the Devil’s Gate Dam reservoir in a way that not only preserves flood protections provided by the dam and its reservoir, but also considers traffic, air quality, natural communities, and water resources to create an integrated and sustainable approach that will benefit all residents of Los Angeles County,” the Save Hahamongna website states.

Three years ago, 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 regarding air pollution, necessary mitigation and cumulative impacts.

The ruling forced the county to rework portions of the environmental documents, and the county scaled back the project reducing the amount of sediment removal from 2.4 million cubic yards to 1.7 million.

In July, Los Angeles Superior Court Judge James Chalfant postponed the trial to allow the two sides to have settlement talks.

The Devil’s Gate Reservoir Restoration Project is a four-year effort

Los Angeles County Public Works will remove 1.7 million cubic yards of sediment from the reservoir immediately behind the nearly 100-year-old dam. In addition to providing flood relief to communities that have endured nearly 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 for local communities.

A large amount of sediment has not been removed from Devil’s Gate since 1994, when workers hauled out 160,000 cubic yards of soil and debris. An additional 1 million cubic yards of soil and debris were dumped into the basin by the Station fire in 2009, which burned more than 160,000 acres in Altadena.