In a shady stretch of the Arroyo Seco near San Pascual Park, three cities and a tight-knit group of neighbors are locked in a fight over how to clean up a polluted creek without tearing up a beloved, and for some, sacred grove.
Pasadena and South Pasadena are pushing a stormwater project that would turn underused open space near the channel into treatment wetlands and infiltration basins. Neighbors and Tribal leaders counter that the plan would level mature trees and drop new infrastructure onto land they view as a cultural landscape. The clash has already triggered lawsuits, a Los Angeles City Council resolution and a full environmental review that will decide whether the compact project actually gets built.
According to the Draft Environmental Impact Report (DEIR), the plan would create two stormwater-capture sites totaling about 3.6 acres: a 1.4-acre San Rafael site and a 2.2-acre San Pascual site. Those areas would be reshaped into treatment wetlands and basins designed to grab and clean stormwater before it flows farther downstream.
The DEIR estimates an average annual water-supply benefit of roughly 320 acre-feet, with about 258 acre-feet recharging local groundwater and roughly 30 acre-feet captured for irrigation at the South Pasadena golf course. Project documents say the work is intended to cut bacteria loads entering the Arroyo and downstream reaches of the Los Angeles River while improving habitat and trail access.
Trees, Habitat and Sacred Ground
Opponents say the math on paper ignores what will be lost on the ground. Reporting by LAist notes that nearly 140 mature trees would be removed within the San Pascual project footprint, more than half of them classified as invasive and highly flammable. The project's appendices from City of Pasadena include an i-Tree planting and benefit analysis that calls for replanting new trees.
Neighbors argue that replacement saplings will not bring back the deep shade, habitat or long-established sense of place that has grown up around the Arroyo banks. Tribal leaders and longtime residents say the groves shelter springs and burial sites that were significant long before the channel was lined with concrete.
Who Is Opposing the Plan
Grassroots groups have turned the narrow strip into a kind of living picket line. Save San Pascual Park has organized weekly stakeouts, circulated petitions and pursued legal action aimed at stopping work in the wooded corridor, according to community materials from Save San Pascual Park.
The coalition argues its lawsuit and persistent outreach helped force the move from a shorter environmental review to a full EIR. Organizers also stress the odd geography of the site: it sits right on the border of Pasadena, South Pasadena and Los Angeles, a three-way split that has complicated public outreach and deepened skepticism about the engineers' design.
Politics at the Border of Three Cities
Pasadena is the lead agency on the project, but Los Angeles officials have not exactly rolled out the welcome mat. Councilmember Ysabel Jurado introduced a City Council resolution calling on the three cities to walk away from the proposal and to protect City-owned parkland until government-to-government consultation with Tribal representatives can take place, according to the Councilmember's office.
The resolution warns of the potential loss of century-old trees and permanent impacts to recreation and habitat on Los Angeles parkland next to San Pascual Park. Pasadena and South Pasadena officials, for their part, maintain that the project will boost water quality, add trail connections and expand public access. Pasadena says it has widened its outreach by hiring a local nonprofit to help explain the plan, according to LAist.
What’s Next: Comments and Court History
Pasadena has formally extended the Draft EIR public review period, with written comments now accepted through 11:59 p.m. on August 1, 2026, according to the city's extension notice. That extra time follows earlier litigation: in 2024, resident Clara Solis and allied neighbors filed a case pressing the city to prepare a full EIR instead of relying on a prior mitigated negative declaration, a move reflected in local meeting records.
Once the comment window closes, city staff will compile responses, prepare a Final EIR and use that document to guide decisions on project approvals and any easements needed for work on Los Angeles parkland.
The choice in front of the three cities is small on a map but big on symbolism: move ahead with a project that would capture stormwater and recharge groundwater while permanently altering a stretch of the Arroyo, or keep a compact stand of mature canopy and open space that many neighbors and Tribal members say cannot be replaced. With the DEIR comment period now extended through August 1, what ultimately gets built will depend as much on lawyers, elected officials and public pressure as on any engineering model.
