Environmentalists on Thursday won a temporary halt to a project to remove millions of cubic yards of sediment from behind Devil's Gate Dam, a project they said was so big it would harm air quality and wildlife habitat in the Hahamongna Watershed Park in the north end of Pasadena.
Los Angeles Superior Court Judge James Chalfant ruled LA County's environmental impact report on the project was insufficient.
Opponent of the plan were pleased with the decision.
"A lot of these flood control areas that they manage are, in fact, bird habitat," said Laura Garrett of Pasadena Audubon Society, which sued LA County to reduce the scope and pace of the sediment removal project. "In fact, sometimes it's the only bird habitat because everything else has been developed."
The county Flood Control District had sought approval to take out up to 2.4 million cubic yards of sediment behind the dam to remove the threat that heavy rainstorms could inundate the dam and flood homes along the Arroyo Seco Channel. The dam's capacity to hold stormwater coming out of the mountains is limited because so much sediment has built up over decades.
In staying the sediment-removal project Thursday, Judge Chalfant ruled that the Flood Control District's environmental impact report was deficient in three areas.
The proposal failed to describe how the county would deal with the impact of the air pollution that would come from the excavation of dirt that has built up behind the dam. The county must rewrite its EIR to clarify that dump trucks on the project meet 2010 AQMD emissions standards.
The county's EIR also did not make clear how the county would replace the habitat that would be removed by the excavation with an equal amount elsewhere, so that will have to be revised, said Mitchell Tsai, attorney for the plaintiffs.
Garrett said that one-to-one ratio of finding new habitat for what's torn out could limit how much habitat the county ultimately removes.
"They're going to have to find so much habitat to mitigate this project, that it would be very smart of them to shrink the footprint of the project and that would make it easier for them to mitigate the habitat," Garrett said.
"Birds like that vast expanse of willow and mulefat forest, and that's where a lot of really special birds nest," Garrett said. "If they carve out the heart of that, then all that habitat is lost."
The judge also ruled the county's environmental impact report did not take into account the accumulated effects of the dirt-removal when combined with a separate project to pipe water from the Devil's Gate Dam reservoir area to a flood control project near Eaton Canyon in the east end of Pasadena.
Thursday's action keeps intact the judge's finding at a February hearing that the county could remove as much as 2.4 million cubic yards of sediment if it ultimately produces an adequate EIR and receives other necessary permits from state and federal regulators.
Under Chalfant's order, the county has to revise the portions of the EIR covering the project's impacts on wildlife habitat and air quality. After a 45-day public comment period, the county can then submit the plan to the LA County Board of Supervisors for approval and file the amended document with the court.