A dry river sparks a fight over water where LA, Pasadena and South Pasadena meet

Along the Arroyo Seco, on a strip of land where three cities come together, a fight is escalating over water.

Pasadena and South Pasadena are proposing to clean contaminated water from the channelized stream, but to build the necessary infrastructure, they’d have to remove nearly 140 mature trees, more than half of which are invasive and highly flammable.

And a portion of the cleaner water would end up irrigating a public golf course.

That fact has been a major point of contention raised by a group of residents on the Los Angeles side of the Arroyo. They have campaigned on social media and in weekly stakeouts to stop the project, which would significantly alter a small creek near the popular San Pascual Park.

Leaders of the Gabrieleño Band of Mission Indians-Kizh (Quiichi) Nation have also rejected the Arroyo Seco Water Reuse Project because the area is sacred and home to burial sites, said tribal chairman Andrew Salas. The tribe has opposed the project since its inception and sent a formal opposition letter last year.

“Long before the channeling of the Arroyo Seco, the natural springs, the sacred springs that were there, it was a traditional gathering place,” he said.

Though the city of L.A. itself has no financial stake in the project, one City Council member has called for the project to be abandoned.

The backlash has been so intense that the city of Pasadena recently hired a local nonprofit, Active San Gabriel Valley, to help with public outreach (the group supported the project when it was first proposed.)

Most everyone agrees that the Arroyo Seco’s water needs to be cleaned and that nature around it should be restored. But how to do that — well, there’s the rub.

Opponents of the project are hoping to protect a small creek in a densely wooded area that straddles L.A. and South Pasadena, near San Pascual and Arroyo parks.

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How we got here

The Arroyo Seco — or “dry stream” in Spanish — is a 25-mile winding stream that has little water much of the year but can swell to a torrent with rains. That’s why, in the late 1930s and '40s after devastating floods, the U.S. Army Corps of Engineers lined much of the channel with concrete.

Pollutants flow into the Arroyo from millions of homes and businesses and miles of freeways and streets that crisscross the watershed. The river has repeatedly received an “F” grade for bacteria contamination in report cards by nonprofit Heal the Bay.

Federal and state law requires California to identify and clean up water bodies that don’t meet quality standards. In 2010, the state adopted bacteria limits for the Arroyo Seco, and identified outfalls (essentially drains) with high levels of contamination. One of those spots was where the San Rafael creek flows into the channelized Arroyo, and it was within Pasadena’s city limits.

Over the years, Pasadena and cities along the upper Arroyo worked to develop a management plan — by 2016, it was approved by the state. In 2019, the cities of Pasadena and South Pasadena secured an initial grant for a joint project to clean water from the arroyo.

This spot where the San Rafael creek flows into the Arroyo Seco has been identified as having high bacteria levels.

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What will the project look like? 

The cities’ engineers identified two sites, both largely inaccessible or unused by the public. They dubbed the first the San Rafael site — about 1.4 acres in Pasadena where the San Rafael creek empties into the Arroyo Seco.

Just downstream, they identified a sliver of densely wooded open space in South Pasadena they thought could be rehabilitated. They called those 2 acres the San Pascual site. They developed plans for both areas to build wetlands with native trees and plants, walking paths, as well as underground infrastructure to treat the water for zinc and E. coli and filter out trash. Construction, they said, would take less than two years.

In recent years, Pasadena and South Pasadena secured nearly $15 million for the project.

Renderings of the Arroyo Seco Water Reuse Project

Renderings and maps from the draft environmental impact report show how the cities of Pasadena and South Pasadena plan to carry out the Arroyo Seco Water Reuse Project, if it goes forward.

Renderings show what the proposed San Rafael site, in Pasadena, could look like. At the bottom left, is what the site currently looks like. This site has little opposition, and would open a space currently inaccessible to the public.

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Courtesy City of Pasadena

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A rendering shows what the San Pascual site is proposed to look like. About a half acre of the site is within L.A. city limits, sparking controversy. At bottom left is what the site looks like now.

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Courtesy City of Pasadena

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This map shows the proximity of the two sites that make up the Arroyo Seco Water Reuse project proposed by Pasadena and South Pasadena.

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Courtesy City of Pasadena

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Opposition grows

One problem? About a half an acre of the San Pascual site is within the city of Los Angeles.

And about 10% of the water captured and treated would end up irrigating the nearby public golf course in South Pasadena, according to the draft environmental impact report. Today, water from the arroyo already helps keep fairways green at the golf course through a diversion that’s been in place since the stream was channelized nearly a century ago, officials said.

“It should be noted that the amount of water supplied to the Golf Course for irrigation will remain the same pre- and post-construction,” the draft environmental impact report states.

The blue icon on this map from L.A. County land records marks the strip of land that has generated the most controversy about the Arroyo Seco Water Reuse Project. These 2.2 acres straddle both L.A. and South Pasadena. There are no plans to alter the surrounding parks and baseball fields.

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The cities put together their first plans for the project in late 2023. But early on they did little community outreach on the L.A. side, and none in Spanish, and soon passionate opposition arose.

In 2024, Los Angeles resident Clara Solis sued the cities to stop the project. To avoid litigation, Pasadena agreed to do a full environmental impact report. In early May, the city released a draft for public comment.

But opponents like Solis say the revised plan is essentially the same and doesn’t go far enough to protect mature trees and existing wildlife habitat.

A few planks of wood and metal casing mark where water has been diverted from the Arroyo Seco to irrigate a downstream public golf course. The diversion has existed since the mid-20th century, when the arroyo was first channelized.

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A diversion from the Arroyo Seco that's existed since the late 1940s sends water from the river to this creek, which eventually goes underground to irrigate a downstream golf course.

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A wild haven in the city 

The San Pascual site is surrounded by several parks — the main section of San Pascual Park, on the L.A. side, just across the channelized river from the proposed project site, and Arroyo Park on the South Pasadena side.

On a recent weekend, the parks were full — people set up picnics on the grass, parents cheered as their kids played baseball. Runners made their rounds.

Solis has lived nearby for more than 20 years. When her children were growing up, they’d spot fish and frogs in the creek and sit under the trees, listening to the birds. Today, she and her dog, Summer, often see a blue heron.

Clara Solis, along with her dog Summer, picks up trash along the Arroyo Seco in June.

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To her, unlike the more manicured parks surrounding it, this spot is a rare wild gem in the middle of the city.

“ There's one huge oak, we call it the mother because it's so big, and she's going to get cut down, and it's just heartbreaking to us,” Solis said.

And construction will undoubtedly affect L.A. residents, whose neighborhoods are closest to the San Pascual project site.

“South Pasadena and Pasadena are not sensitive to the people of Los Angeles,” said Robert Acosta, who lives across the street on the L.A. side. “No one ever sent notification to me that they were going to do this.”

The mother oak.

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Small fish and tadpoles can be found in the creek running through the proposed project site near San Pascual Park.

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That’s why Solis and other volunteers launched the group Save San Pascual Park.

With the help of social media and local organizing, they built a movement and collected signatures. The group has accused Pasadena and South Pasadena of using the project to steal water and land from L.A. and say it's a case of environmental injustice.

The all-volunteer group Save San Pascual Park has been posting signs at the San Pascual site.

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In late May, the group successfully urged L.A. City Councilmember Ysabel Jurado, who represents the area, to formally oppose the project. The L.A. City Council sent her resolution back to committee.

L.A. County Supervisor Hilda Solis and state Sen. María Elena Durazo had more success — they both sent letters requesting Pasadena extend public comment, which the city granted for 30 days.

But not everyone is against the project. Pilar Reynaldo, who has lived in nearby Garvanza for 14 years, fully supports it.

“ I have reimagined the Arroyo many times with the removal of invasives and the plantings of natives,” said the avid walker and certified master gardener, “and I'm really excited about this project because it would do exactly that.”

She argued that the planned sites would ultimately better support local wildlife — and nearby residents.

“The South Pasadena site has only been inhabited by unhoused people who have set many fires, which presents a real danger to the community,” she said. “ I've never seen anybody other than unhoused people and a man masturbating.”

Catching pollution at the source

On a recent tour hosted by Save San Pascual Park, a group of about a dozen people walked along the Arroyo Seco toward the San Rafael site upstream. Clara Solis pointed out a small pipe leading out of the San Pascual horse stables into the Arroyo.

Solis argues that stopping pollution starts at the source — such as the stables, Johnston Lake and a golf course upstream — not through large infrastructure projects after the fact.

A pipe and ditch directs water from the San Pascual stables towards the Arroyo Seco. It's one of many likely sources of high bacteria levels in the stream.

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Pasadena, though, argued that’s impossible — and that state law restricts their options. The city has tested San Rafael Creek and fixed leaky sewer mains, Pasadena city engineer Brent Maue said. Still, fecal bacterial levels remained high.

“We're forced under the law to reduce pollutants, and unless you can find the point source that's causing it, then you have to build a project at the compliance point, and that is where the water comes into the Arroyo Seco,” he said.

For decades residents, engineers, scientists and environmentalists have debated how to balance engineered flood and pollution control with restoring the Arroyo to a more natural state.

Tim Brick, executive director of nonprofit Stewards of the Arroyo Seco, has long pushed for restoring the stream to largely its original state to support wildlife and recreation. That could in turn improve water quality, as plants, trees and soils can filter out pollution.

Some projects have helped, he said.

“But the city [of Pasadena], particularly in recent years, has not done a good job of following through with maintaining the restoration projects,” Brick said.

An egret stalks food in the Arroyo Seco on a recent weekend.

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Clean water for a golf course?

On their recent tour, the Save San Pascual Park group carefully made their way along the dirt path within the proposed San Pascual site. They ducked under branches and warned each other of poison oak. Under the trees, the sounds of the city faded, replaced by chirping birds, rustling leaves and flowing water.

The group walked past a huge oak — Solis’s “mother tree” — as well as invasive and highly flammable tree of heaven and Mexican fan palms, many charred by a recent fire. Several ducks drifted in the creek. Some trash peppered the greenery.

“ I don't see the neglect,” said Mount Washington resident Yael Pardess. “I see the beauty. I see the potential, and I think it's a place that really makes you forget you're in L.A.”

Most of this spot is technically in South Pasadena, but Pardess said the community alongside L.A. City Council District 14 has hosted cleanups here and removed “truckloads” of trash.

Mexican fan palms dominate the San Pascual site. Many are charred black from a recent human-caused fire.

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Pardess contends that the area just needs maintenance.

“There's so much life in here, and we cannot eliminate this gem, even for the sake of clean water,” she said. “The solution for a park that is neglected is not to destroy it, it is to restore it. They don't have the money for that. They have the money to destroy it.”

The group reached the end of the trail, where the water pooled into a small pond. This is where the creek goes underground to the downstream Arroyo Seco Golf Course, a public and popular course owned by the city of South Pasadena with green fees of $29 or less.

Water not used for irrigating the golf course would go into the project’s infiltration basins, where it would seep underground.

“Depending on local geologic conditions, infiltrated water may contribute to groundwater storage, support downstream aquifers, or reemerge elsewhere as groundwater seepage over time,” Maue said. “In other words, the project changes the pathway the water takes, but it does not simply remove that water from the watershed.”

The proposed project calls for planting only native trees, unlike these towering Mexican fan palms.

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The creek running through the proposed San Pascual site.

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What happens next? 

For now, water quality regulators are not imposing fines, which could be as much as $10,000 per day, while they review the latest plans.

Reynaldo, the Garvanza resident, said she hopes a middle ground can be reached.

“It would've been great had the channel never been filled with concrete, but it was,” she said. “Now there are so many communities that have been built on the floodplain.  I think that perfect is the enemy of the good, and these projects do not impede on the possibilities of, maybe in the future, they are able to take some concrete out.”

LAist intern Sena Chang contributed to this report.