A complex, $15 million plan to re-use water in the Arroyo Seco has closed its public comment review period, setting the stage for the city of Pasadena’s responses to comments in the coming months.
The Arroyo Seco Water Reuse plan — a collaborative project between Pasadena (the lead agency) and South Pasadena — is facing pressure from a state mandate, a Los Angeles City Council member and a coalition of local residents.
The main goal? It’s about water quality. The mission is to address California state officials’ concerns spurred by bacteria levels from tributaries – including the Arroyo Seco channel – that flow into the Los Angeles River. The project will be captured and treated via man-made wetlands and infiltration basins across two sites to filter out E. coli bacteria and heavy metals from urban runoff before they reach the river.
The plan targets key water discharge points, called outfalls, where those bacterial levels exceed limits set by the L.A. Regional Water Quality Control Board.
But the project has spurred concerns from various corners:
–An L.A. City Council member and nearby residents fear the project’s impact on a neighborhood park considered by many to be a beloved green retreat;
–Tribal leaders fear the city will move forward with the project, causing destruction of possible ancestral remains and artifacts, after they provided substantial evidence of their presence.
–Some critics demand a more “nature-based” approach, decrying tree removal, industrial applications on public park land and the impact of excavation on a wild, wooded area beloved by park users.
The plan’s organizers say the result will be cleaner, healthier water and that park areas will be even more accessible.
Here is a breakdown of top questions about the project.
What is the Arroyo Seco Water Reuse project?
Facing pressure from the state, the main goal for local officials is to address bacteria levels from tributaries that flow into the L.A. River, which includes the Arroyo Seco channel.
The project comprises two locations: the San Rafael and San Pascual sites. The San Rafael site is 1.4 acres in Pasadena southwest of the San Rafael overpass and to the west of the channel. Another 2.2 acres of land is at the San Pascual site — 1.7 acres in South Pasadena and 0.5 acres in L.A.’s San Pascual Park, near San Pascual Avenue and Stoney Drive.
Through diverting dry weather flows, infiltrating and treating water from the Arroyo Seco channel, 157 pounds of zinc will be removed per year at the San Pascual site and 12.5 pounds per year at San Rafael. Less than 10% of water would be captured for irrigation at the nearby Arroyo Seco Golf Course in South Pasadena, part of an “existing, historic irrigation system that captures water runoff,” according to a Pasadena city document.
Nearly 140 trees would be removed from both sites — 82 non-native Mexican palms, 29 protected trees and 14 trees deemed significant under city ordinances. The city also cites some of the non-native trees particularly the palms as fire risks.
The project would plant 216 trees; the city of Pasadena purchased native sycamores and is currently propagating 52 native oaks.
New pathways would increase walkability and invasive species would be replaced with native plants aligned with the chaparral, sage-scrub and riparian habitat, according to the plan.
The city’s draft environmental impact report states that construction would begin in fall 2026 and would last for 17 months, with completion in June 2028.
How did we get here?
The project has been in motion since 2019, but the issues go back earlier. In 2010, the L.A. Regional Water Quality Board — an agency that addresses water quality concerns — established a total maximum daily load (TMDL), the capacity for water to absorb pollutants including E. coli bacteria and metals.
Both cities have been out of compliance since September 2023 and face potential fees — at least $10,000 a day, according to city of Pasadena’s project manager, Christina Monde.
A spokesperson from the L.A. Water Board confirmed that no fees have been levied against the cities.
Recent data from the two cities’ 2025 stormwater permit reports “show that the bacteria standards are still being exceeded,” according to the board’s spokesperson.
The project is in its public review period for the EIR, a result from settled litigation in 2024 from a local resident who urged for a higher level of review from Pasadena’s previous mitigated negative declaration. The deadline was extended twice; the last day to submit comments was Saturday, Aug. 1.
The cities obtained more than $14 million through a grant from California’s Department of Parks and Recreation, L.A. County’s Safe Clean Water program (Measure W) and local return dollars.
How does the project work?
The project is considered a constructed wetland, defined by the U.S. Environmental Protection Agency as a treatment system that uses “natural processes” to improve water quality.
“You can think of it as like a filter and as the water moves through that filter,” Richard Ambrose, a professor at UCLA’s Institute of the Environment and Sustainability, said. “The pollutants get removed out and then when the water gets through on the other side, it’s cleaner.”
Pasadena’s City Engineer Brent Maue explained the process at each site in an email. At the San Rafael site, dry-weather flows and stormwater would flow by gravity from San Rafael Creek and through a rock-lined channel. A forebay would remove sediment before entering the treatment wetland, with water both infiltrating into the soil or moving through a filtration system before returning to the channel.
At the San Pascual site, water moves through an existing diversion and an underground separator to remove sediments. A pump station lifts the water into an upper level of the constructed wetlands, with the lower level serving as a shallow pond for wildlife during dry weather. After treatment, water would be “conveyed to the existing golf-course irrigation system or allowed to infiltrate through the unlined portions of the treatment basins,” Maue wrote.
Is the project sufficiently ‘natural’?
Based on discussions with residents and submitted public comments, some foes of the project seek a more nature-based approach – including removing the engineered aspects or targeting sources of pollution specifically.
“Water-quality mandates can be met without resorting to bulldozing and installing industrial infrastructure in these sites,” Barbara Eisenstein, the founder of Friends of South Pasadena Nature Park, said at a community rally in June.
Some critics argue it is too engineered, utilizing industrial processes to do what nature can do itself. The city argues that the project is nature-based and that the engineered aspects focus on moving water while still letting natural processes clean it.
Maue, Pasadena’s engineer, said that the project is best described as an “engineered, nature-based treatment system.” He wrote that the engineered infrastructure “provides the control and reliability needed for the natural systems to function as intended.”
Infrastructure such as diversion structures, forebays, separators, pumps, pipes, valves and outlets regulate water amounts, control movement and remove sediments. Concrete and lined channels “are used only where necessary” to move water, maintain habitat ponds and do not line areas used for infiltration, according to the city.
UCLA professor Ambrose said the L.A. River watershed is not his expertise but based on his research background in wetland restoration and work as a past consultant for other Southern California cities on similar projects, he said the cities’ project aligns with his expectations for a nature-based solution.
“One thing that’s complicated — it’s in this project and virtually every other project — is that the water doesn’t just magically go into the wetland and magically leave,” Ambrose said. “Oftentimes, there are construction elements that you have to put into it in order to get the water to move through, so that it can be treated by these natural processes.”
He added: “That might be where some of the discrepancy in the views of this project come in, is like how much is engineered by traditional hard engineering versus how much is letting nature do the work.”
Maue explained that the city took effort to identify and eliminate potential upstream sources but ultimately “did not identify a single, consistent bacteria source whose correction alone would achieve the required reduction.”
“Even though addressing pollution at the source is good, it’s challenging because so many dispersed actions by so many different entities have to be employed,” UCLA professor Ambrose said. “Often the larger regional projects are the most efficient and cost-effective ways to remove pollutants and infiltrate stormwater. This is why the Safe Clean Water program is largely funding these.”
How is Los Angeles involved?
The San Pascual site of the project includes 0.5 acres of L.A. parkland – in San Pascual Park, which covers about two and a half acres in total. The two cities would need to enter into an agreement with the city for property use, construction and maintenance of that portion.
Pasadena’s engineer Maue wrote that “no agreement has been finalized or approved at this time.”
In late May, L.A. City Councilmember Ysabel Jurado, who represents the areas of Boyle Heights, Downtown and northeast L.A., introduced a resolution in opposition to Pasadena and South Pasadena’s project. A City Council vote on July 1 was delayed after the resolution’s language was amended and it was referred back to the Rules, Elections and Intergovernmental Relations committee.
A spokesperson from Councilmember Jurado’s office said her office “has not negotiated or agreed to terms granting the project use of this land.”
The resolution cites the destruction of trees and other environmental impacts, the Gabrieleño Band of Mission Indians-Kizh Nation’s call for “full avoidance” of the site and “failure to engage in meaningful community dialogue.” It would also declare that “no San Pascual parkland be used for industrial infrastructure.”
When asked, Pasadena’s project manager Monde has not responded to specific concerns about Councilmember Jurado’s resolution. The city, however, will respond to any public comments sent in the coming months, as part of the review process.
If the L.A. City Council votes on Councilmember Jurado’s resolution, the city will likely have to respond or negotiations may be impacted.
How have local tribes weighed in?
Under AB 52 of the California Environmental Quality Act, agencies are required to consult with tribes during the environmental review of projects. Pasadena’s EIR states that a sacred lands file search came back positive for the project’s area, meaning there are records of ceremonial, cultural or religious sites.
According to the draft EIR, the city of Pasadena reached out to the Gabrieleño Band of Mission Indians-Kizh Nation and the Gabrielino-Tongva Nation. The Gabrielino-Tongva nation did not respond and the city continued consultation with the Gabrieleño Band of Mission Indians–Kizh Nation. The following mitigation measures were included: designate the Gabrieleño Band of Mission Indians–Kizh Nation as the tribal monitor during ground disturbing activities and cease activities upon unanticipated discovery of tribal cultural resource objects, human remains or ceremonial objects.
During a City Council meeting on July 1, Councilmember Jurado amended her resolution to make it “consistent with our land acknowledgement policies.” Conversations with residents and public comments indicated the amendment was unexpected; members of the Gabrieleño Band of Mission Indians-Kizh Nation opposed the amended language, arguing that other tribes “were not involved in those years of consultation.”
Several comments submitted by tribal representatives of the San Gabriel Band of Mission Indians, Gabrieleno Tongva asked for Councilmember Jurado’s resolution to be withdrawn from consideration or amended “to ensure that all culturally affiliated tribes identified through the Native American Heritage Commission have been afforded an opportunity to participate in meaningful consultation.”
Last July, tribal Chairperson Andrew Salas of the Kizh Nation submitted a letter to the city of Pasadena urging for “full avoidance” of the area due to substantial evidence of encountering ancestral human remains.
“The substantial evidence, that component, is something as to why there were no other tribes involved in this process,” Matthew Teutimez, the Kizh Nation’s tribal biologist, said in an interview. “Our tribe was the only one that possessed the substantial evidence of the burials that were found of tribal cultural resource objects that we find in similar locations.”
Salas discussed feeling like “all we are is a check box.” He added: “(The city) can check off a box saying that they reached out to consult. However, when they’re provided substantial evidence, they avoid it — they ignore it.”
Pasadena’s project manager Monde said that after tribal consultation, there was no opposition to the project until Salas’ letter of full avoidance. She discussed that his letter was “not so much opposing the project as requesting specific environmental issues to be studied in the EIR.”
Because the Gabrieleño Band of Mission Indians–Kizh Nation is the tribal monitor for the project, the city will continue to work with the tribe moving forward, Monde said.
What do community members say?
During a San Pascual site walkthrough with organizers of the group Save San Pascual Park in May, many discussed how they value the green space, especially next to the 110 freeway. They fear losing a safe haven of trees amidst an urban landscape with thousands of cars driving by each day.
Of the entire San Pascual Park, however, only a small portion – approximately 0.5 acres located near San Pascual Avenue and Stoney Drive – would be impacted by the two cities’ project, project officials say.
“Every time we’re down there, it feels like our lungs are asking for deeper breaths,” Amada Segura, a resident involved in the group, said. “It’s just so enriching for me to be able to, in the city of Los Angeles, have that connection with nature.”
Clara Solis, the resident who filed the lawsuit to establish the EIR and organizes with Save San Pascual Park, shared a similar sentiment to what the area means to her.
“My kids, as toddlers, would go and see the fish and we’d walk here all the time,” she said. “Now they’re adults and they still enjoy the outdoors — and I think it’s partly because we were able to enjoy this wildlife.”
According to 150 public comment files received from the city by Pasadena Star-News in June, a majority opposed the project. Many shared concerns about the environmental impact, the removal of trees, the diversion of water to Arroyo Seco Golf Course and the presence of sacred burial sites.
A coalition of more than 20 organizations oppose the project, including the neighborhood councils of Arroyo Seco, Eagle Rock, Highland Park, Lincoln Heights and Los Feliz.
Some residents argue that the sites have been neglected, referencing leftover trash, past fires set by homeless people and a makeshift hill for bikes that obstruct accessibility at San Pascual.
“The palms that are in there are charred to a crisp and a few of the native trees are also beyond saving,” L.A. resident Pilar Reynaldo said. “I don’t see how leaving it in that state of real neglect is beneficial.”
Reynaldo expressed disappointment in Councilmember Jurado’s resolution, arguing that the L.A. City Council doesn’t have jurisdiction over the two cities’ project. She was also concerned about the potential fees both cities are facing.
“None of our taxpayer dollars should be going to paying compliance fees on a $10,000 a day basis because disinformed people are trying to stop this project,” Reynaldo said.
The city of Pasadena has been working with local nonprofit Active San Gabriel Valley to provide community outreach and engagement including site tours and canvassing.
What’s next?
Since Councilmember Jurado’s resolution opposing the project is still in committee review, it’s unclear when a vote by the L.A. City Council will take place.
The Arroyo Seco Water Reuse project concluded its public review comment period on Aug. 1. The city of Pasadena, as the lead agency, will have to respond to each comment received, which could take months. According to the city’s timeline, a future public outreach meeting could take place before proposed construction.
Camelia Heins is a correspondent with the Southern California News Group.