Scraping the bottom
City officials and local residents join forces against sediment removal plans for Devil’s Gate Dam
By André Coleman 01/02/2014
Pasadena officials opposed to a five-year, $70-million sediment clean-up of Devil’s Gate Dam in Hahamongna Watershed Park, which they say could increase health risks and negatively impact local traffic, are making their feelings known in a letter to Los Angeles County officials pushing the controversial project.
County Public Works Department officials want to remove up to 4-million cubic yards of sediment and build up around Devil’s Gate Dam, located in the southern portion of the park, but the excavation would also force workers to remove trees and vegetation in the area.
Along with ordering the drafting of a letter expressing their concerns about the project, on Dec. 16 the Pasadena City Council instructed City Manager Michael Beck to hire a private environmental consultant to conduct an independent analysis of the county plans and create a task force to further explore the issue.
The revelations were made in an environmental impact report (EIR), which was pushed by Supervisor Michael Antonovich. According to Antonovich’s Director of Communications Tony Bell, no decisions have been made yet on how to remove the sediment.
“Our position has always been to discuss the issue with the community,” Bell said. “The community’s position is the highest priority.”
Antonovich insisted on a meeting at Jackson Elementary School in Altadena with environmental consultant Brian Mooney of the Chambers Group, a firm contracted by the county to conduct the EIR. The report states that four of the five options, with option no. 4 including sluicing or wincing away the debris over 150 years, would require 50 trips by dirt-hauling trucks every hour six days a week between the dry period of April 15 and Dec. 15 for five years.
Two days before the council met, dozens of residents from Pasadena, La Cañada Flintridge and La Crescenta linked hands and stood on the bridge overlooking the dam in protest of the project.
The public comment period for the draft environmental report ends Monday. The sediment removal project is scheduled to begin in 2015 and will last for at least five years.
“He has seen all of the alternatives,” said Antonovich’s Planning Director Edel Vizcarra. “The process is not over yet. We are very concerned with one truck trip per minute ratio. It has got to get cleaned up. We cannot just sit back [and do nothing]. The valves have to be unclogged. The purpose of the dam is for flood control. We were getting letters from the Rose Bowl and the Rose Parade committee. We have heard from the Altadena Town Council and La Cañada residents. There are a lot of interests out there, but the one thing that everybody agrees on is something needs to be done.”
The last time the county removed a significant amount of sediment from the area was in 1994, when workers hauled out 160,000 cubic yards of soil. Since that time, about 2.7 million cubic yards have built up around the dam. An additional 1 million cubic yards of debris was dumped into the area by the Station Fire in 2009, which burned 160,000 acres in Altadena, Pasadena, La Cañada Flintridge and Acton.
“They have not been maintaining this reservoir,” said Pasadena Councilman Victor Gordo. “They are trying to play catch-up at our expense, and they’re trying to play catch-up in a way that potentially destroys both a riparian and ecological resource, not to mention all of the recreational aspects of Hahamongna.”
The county contends sediment compromises the dam’s ability to contain debris and floodwaters. If it is not removed, locations along the Arroyo Seco downstream from the dam — including the Rose Bowl, the Pasadena (110) Freeway and neighborhoods in West Pasadena — could be in danger of flooding.
Despite those dangers, limited options to remove the sediment have left many people worried about the potential impacts on Hahamongna Watershed Park. Local residents have long been fighting to maintain the 1,300-acre park as green space for families and hikers. Located between Altadena and Pasadena in the Upper Arroyo Seco, Hahamongna provides access to foothill trails in La Cañada Flintridge and US Forest Service property further north, into the San Gabriel Mountains.
The park is managed by the city under guidelines laid out in the Hahamongna Watershed Park Master Plan, which calls for the city to restore, enhance and reestablish the historic native plants of the Arroyo Seco. In April, the city abandoned plans to use a state grant to place a soccer field in the park.
The property, which gets its name from the Native American Tongva people who lived in the Arroyo Seco hundreds of years ago and means “flowing water, fruitful valley,” was sold to the Metropolitan Water District in 1970 for $490,000. The land was sold with a stipulation that its usage would support open space and recreational activities. In 2005, MWD sold the land back to the city for $1.2 million after the agency admitted that it had no plans for its use.
“When I speak to people in the park about this project they are horrified,” said Altadena biologist Lori Paul. “There has not been proper notification. The whole area is going to be scraped. It goes from the dam to [nearby Jet Propulsion Laboratory] and turns it into a large scraped crater. It is going to be useful to JPL for testing moon rovers, but not for much else. It is going to take out the trees and shrubbery that slow flood waters. It will destroy Hahamongna as we know it.”
The EIR states:
“The storms that occurred in the two wet seasons after the [Station] fire increased sediment accumulation in the reservoir by more than 1 million cubic yards. This major sediment inflow significantly reduced the reservoir’s capacity and also buried a large portion of the reservoir vegetation, although significant amounts of vegetation, including numerous mature willow trees remain present. In its current condition, the reservoir no longer has the capacity to safely contain another major debris event; and the outlet works have a risk of becoming clogged and inoperable.”
The EIR does not mention potential health and traffic impacts of the five-year project.
“[The city] needs us to get the county’s attention,” said Laura Garrett, who chairs Pasadena’s Environmental Advisory Committee. “The county has made no scientific case for removing this sediment.
They are using fear-mongering and the press when they say the Rose Bowl would be washed away if they don’t remove sediment. It will increase cancer, emphysema and asthma rates across the city, not just the neighborhood around the Hahamongna where trucks will be driving by once per minute.”
Several local schools are close to Hahamongna, including Cleveland Elementary School, Flintridge Prep, and La Cañada and John Muir high schools. Officials with the Pasadena and La Cañada Unified school districts have expressed concern along with eight other city agencies in Pasadena.
“We have a responsibility as the owners of the property to properly measure whether or not the county is overburdening the easement and I think in this case there’s clear evidence they intend to do that,” Gordo said.