The cities of Pasadena and South Pasadena have proposed a restoration project along the Arroyo Seco aimed at addressing water quality issues caused by E. coli bacteria and zinc pollution. The plan focuses on reshaping two parcels of land near San Pascual Park, a green space located between South Pasadena and Highland Park. The project involves removing several hundred trees, including a significant number of invasive Mexican fan palms, creating infiltration basins, and widening the stream to improve groundwater recharge and reduce contaminants flowing into the Los Angeles River.

Pasadena officials say the project is necessary to comply with a 2010 resolution by the Los Angeles Regional Water Quality Control Board, which set limits for bacteria levels in the watershed. The cities have secured nearly $15 million to fund the initiative, which Pasadena says could help avoid fines of up to $10,000 per day for failing to meet water quality standards. City engineers consider the San Pascual site one of the few local areas suitable for wetland restoration and water filtration, while project managers emphasize that the improvements will increase public access, safety, and aesthetic value.

However, the proposal has sparked strong opposition from local community groups, environmental activists, and some elected officials. Opponents argue that the existing vegetation, though dense and unmanicured, provides much-needed green space in an urbanized area and serves as a natural refuge for residents, especially those without air conditioning. Some have highlighted concerns about the project's impact on tribal sites, citing potential disturbance to ancestral human remains connected to the Gabrieleño Band of Mission Indians — Kizh Nation. The tribe’s representative called for a full avoidance of the area due to its cultural and historical significance.

Community advocates also criticize the city’s communication efforts, saying initial notices about the project were limited in scope and only distributed in English, leaving many nearby residents uninformed. A lawsuit was filed in 2024 challenging Pasadena’s environmental review process and pushing for a comprehensive impact report. Protesters and grassroots organizers have launched campaigns on social media and held public demonstrations opposing tree removal and construction activities. Some describe the area as a cool, shaded space offering relief from surrounding urban heat, while others express worry that the planned changes will erase a natural, untamed landscape.

In response, city officials dispute claims that the area is pristine, citing issues such as overgrowth, unauthorized trails, graffiti, presence of unhoused individuals, and fire hazards posed by invasive palm species. They maintain that the project will enhance the site’s accessibility and community usability while addressing environmental and safety concerns.

The draft environmental impact report is currently open for public comment through Saturday, and a community meeting to discuss the project will be scheduled. Residents and stakeholders continue to weigh the goals of environmental restoration and cultural preservation against those of maintaining existing green space within a rapidly urbanizing region.