By Steve Scauzillo, October 24, 2013
The Devil’s Gate reservoir basin including the Devil’s Gate Dam and
Hahamonga Watershed Natural Park in Pasadena, Monday, Sept. 14, 2009.
PASADENA >> A long-awaited environmental review of the Devil’s
Gate Dam project released Thursday estimates the removal of between 2.4
million and 4 million cubic yards of backed-up sediment will require a
maximum of 400 truck trips per day for five years.
environmental impact report for the Devil’s Gate Dam sediment removal
project says the project, which may begin in 2015, will pollute the
local air, cause aesthetic impacts and add to traffic — impacts listed
However, the 675-page EIR released by the Los
Angeles County Department of Public Works also says the $70 million
project will not have any significant environmental impacts in 14 other
areas, including the habitat behind the dam that is home to birds, bats
Pasadena environmental groups and residents have opposed the
sediment-removal plan, saying the mule fat and willow ecosystem that has
sprung up as a result of debris flows since the last dredging project
in 1994 serves as a natural part of the Hahamongna Watershed Park
enjoyed by joggers, walkers, hikers and birders.
Although county engineers say they are proposing an alternative that
would leave an island of natural area but clear out additional edges for
more effective flows, the early reviews of the complicated report
reflect deep concerns.
“This is not a good plan for the environment nor for the birds,”
said Laura Garrett, conservation chairwoman for Pasadena Audubon.
Garrett had attended numerous scoping meetings in 2011 with the county
and asked that some of the area be left with water for birds and
wildlife to thrive.
“Instead, there will be between 50 and 60
acres that they want to keep permanently clear cut. You would only have
rodents and lizards there. This is a much more severe plan than we saw
during the public scoping time.”
After the 2009 Station Fire burned 160,000 acres of Arroyo Seco
watershed, more than 1 million cubic yards of debris came to rest at
Devil’s Gate Dam.
To some, the debris launched a verdant plant
ecosystem and attracted a nesting pair of least bell’s vireo, a bird
listed as a national endangered species, as well as state listed species
including the western pond turtle and the coast range newt, according
to the report.
But county engineers say the project is a matter of
public safety. They say the debris flow may clog the valves and gates
of the dam, rendering it unable to protect the downstream communities of
Pasadena, South Pasadena, Highland Park, Hermon, Montecito Heights,
Mount Washington and Cypress Park, as well as the 110 Parkway and the
Rose Bowl during a 50-year storm.
“If we had a big storm event we would have some flooding down in
the Arroyo Seco,” said Keith Lilley, principal engineer on the project
with the county DPW.
County workers have removed small amounts of sediment each year since 2010 to keep the dam operating, he said.
The amount of debris to be removed will be at least 2.9 million cubic
yards, or more, depending on debris amounts from future storms, Lilley
said. The amount of debris will equal millions of tons, he said.
order to remove the sediment from the reservoir, trees and vegetation
growing within the excavation areas will need to be removed,” according
to the EIR.
Most of the time, the area behind the dam will be scraped by
bulldozers and debris will be loaded onto double-dump trucks that will
travel to three sites: the Waste Management facility in Azusa, the
Vulcan Materials Reliance facility in Irwindale or the Manning Pit near
Vincent Avenue and Arrow Highway in Irwindale, the report stated.
The trucks will also remove sediment temporarily stored behind Hahamongna Park at a defunct spreading ground.
county is hosting three meetings on the project: 6-8 p.m. Nov. 6 at the
Rose Bowl Stadium Visitors’ Locker Room, 1001 Rose Bowl Drive, Pasadena
(enter at Gate A, Park in Lot F); 6:30-8:30 p.m. Nov. 14 at Jackson
Elementary School Auditorium, 593 West Woodbury Road, Altadena; and 2-4
p.m. Nov. 16 at Community Center of La Cañada Flintridge, 4469 Chevy
The comment period has been extended until Jan. 6. Send email comments to firstname.lastname@example.org.
To view the EIR online, go to www.LASedimentManagement.com/DevilsGate.