Meeting on Big Dig Concerns Draws Diverse Crowd

A Los Angeles County official told a crowd of more than 250 people at a recent meeting that his agency will consider monitoring possibly toxic particulate matter and gases that some community members believe will pose a health hazard during of the Devil’s Gate Dam sediment removal project.
“We will take a look at if there’s a possibility to do a kind of stack-type monitoring or tailpipe-type monitoring and then come back with those results,” said Dan Lafferty, an interim deputy director for the county Department of Public Works, following the meeting at the La Cañada High School auditorium. “Just because we have approval to move forward with the project, and the project is configured the way it is now, doesn’t mean that we are not considering additional mitigation measures or that we would not entertain suggestions from others on how to mitigate this project even further.”
A group of La Cañada Unified School District parents, including the LCHS PTSA president, helped put together the meeting last week. The group aims to inform residents about what it says are the potential pollution and negative health impacts of the sediment removal project, nicknamed the Big Dig.
The group has been emphasizing its concerns about trucks that are expected to make 425 daily diesel truck round trips at the site, traveling through the intersection at Berkshire Place and Oak Grove Avenue and onto 210 Freeway entrances in both directions.
Lafferty was among the officials who took part toward the end of the meeting with LCUSD Superintendent Wendy Sinnette.
Sinnette said in a question-and-answer period that the district is looking at replacing filters at school sites and has hired an environmental consultant to conduct an independent analysis of health risks from the project. She added her district is also looking ahead to summer school and the possibility of holding a PE class indoors.
“As all of this unfolds, we’re engaging in ongoing analysis to make sure that our priority is the health and safety of our students and staff,” Sinnette said. “That’s simply our No. 1 priority.”
District parent Elizabeth Krider, who holds a Ph.D in chemistry and has worked at Caltech, and LCHS PTSA leader Tamar Tujian spoke at the meeting. Both have said they want answers to their concerns.
The project includes an initial process of removing sediment behind the dam at Hahamongna Watershed Park to increase flood protection and restore habitat within the Arroyo Seco Watershed.
Phase 1 work to clear out trees and vegetation began in late November, and the portion of the project that will include truck traffic is set for April of next year, officials have said.
In November 2017, the county Board of Supervisors approved a scaled-down project to remove 1.7 million cubic yards of sediment. The project began after a nine-year process that included feedback from local residents, environmental groups, the cities of La Cañada Flintridge and Pasadena and the community of Altadena.
During the meeting, slides and maps were shown of the proposed truck hauling schedule and speakers.
Heather Wipfli, a district parent, assistant professor in the Department of Preventive Medicine at the Keck School of Medicine at USC and associate director for the university’s Institute for Global Health, said the particulates caused by the truck traffic were a health risk to children and adults.
“The point is that diesel emissions have a very high percentage of very, very small particles,” Wipfli said. “These particles go very, very deep in our lungs and therefore cause the most health effects, the most damage to our lungs.”
Krider, in her presentation, added there is no current smog check for heavy-duty vehicles to check for hazardous emissions and said the U.S. Environmental Protection Agency had shown the trucks’ emission control systems had failed previously.
After the Wednesday meeting, a woman passed out a business card of the Pasadena activist group “Save Hahamongna” that refers to the website at The site has a petition to “save Hahamongna watershed for the future” by means including a “slow, steady sediment removal plan” that reduces the acreage to be excavated and other negative impacts by 30%.
Attendees were asked to fill out an “interest card” to help participate. Some of the ways to help included attending an event or a Board of Supervisors meeting.
The goal of the parent group, organizers said, was to encourage supervisors to adhere to air quality standards set in a 2017 environmental impact report approved last year to create safeguards for children.
“We really hope the county representatives who are here tonight will listen to our concerns and act on them,” said Kelly Davis of the LCHS 7/8 PTA.
Claudia Joe, who has two children attending district schools and lives in LCF, said after the meeting she didn’t believe anything could alter the project.
“It’s the first time I’ve been to a meeting and everything feels like once it starts, and there’s no regulation, you cannot stop it,” Joe said. “Unless [the county] tries hard to put some regulation in place before April, I would not feel comfortable with the project at all.”
Lafferty, however, said the project was not going to stop despite the concerns.
“At the end of the day, we do have to address the flood risk to those downstream residents,” Lafferty said. “So we do have to move along with the project, but if there are things that we can incorporate to make it a better project, and we can do so without breaking the bank, we would absolutely incorporate those things.”
More information on the project can be found at, or via email at

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