LOS ANGELES — To many locals, the Los Angeles River — hugged by concrete embankments and heavy vehicle traffic — hardly seems like a river at all.
The waterway bisecting the city was converted to a giant storm drain nearly a century ago to contain flood waters. Today, it's an extension of the urban network of concrete, running beneath freeways and bridges as it collects all kinds of refuse: spent tires, scrap metal, trash thrown from car windows.
But when Doug Rosenberg came upon a shopping cart tipped over in the river's shallow waters back in 2020, he saw the potential to meet nature halfway.
"It had begun to bloom some greenery around it, and there was a great blue heron perched on the cart, hunting in this little spot," Rosenberg recalled. "That was when it clicked for me — that any 3D geometry at all in that river channel will trap sediment, will begin a micro-bloom of ecosystem."
The 36-year-old artist saw an amusing paradox — life sprouting from the metal cart — that planted the seed for his next project: a pop-up wetland in the middle of the LA River.
In a desolate part of downtown, he pushed large rocks from the riverbanks into the water and arranged them in loose, concentric circles. The structure would trap sediment, allowing life to take root.
In other words, Rosenberg produced a patch of watery land — like a marsh or swamp — to support plants and animals.
Over the course of 10 weeks, the simple assemblage of rocks spawned a totally new 10-by-20-foot green island in the middle of the 100-foot-wide channel.
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Rosenberg calls it performance art: a visual statement that carries a call to action. The wetland installation isn't quite what he'd call "impactful ecology," but rather a work of art to show environmental good can be low-tech and small-scale.
"The impetus behind this project is to show that the barrier to entry doesn't exist. To basically provide a simple format for action," he said.
Guerrilla gardeners
It's not so much that the barriers don't exist — they do — he's just flouting them, city officials say. Despite his good intentions, none of this is legal. He's a guerrilla gardener: someone who plants where they're not supposed to. The federal government deems this flood control channel "navigable water," providing protections under the Clean Water Act and making any unauthorized changes to its course illegal. That includes obstructions and modifications in the channel, such as dredging or disposal of materials like rocks.
Across the country, as urban development replaces tree cover and natural landscapes with buildings and parking lots, guerrilla gardeners flout local ordinances to disperse seeds or otherwise alter their environment, usually with an overriding mission to reclaim underused public spaces. They seek to grow healthy produce in urban food deserts, capture greenhouse gases and beautify their neighborhoods.
The movement has taken many forms, from creating a verdant oasis for the nation's largest housing project in New York City, to planting a front-yard vegetable garden in defiance of state law in Florida, to grooming a busy bike path in Seattle.
Here in LA, Rosenberg's guerrilla tactics include trespassing and planting without permits in the publicly managed waterway. Getting to his wetland requires jumping railroad tracks and scaling down the steep side of the channel to the riverbed. But as far as he's concerned, it's open to the public.
"I feel like it's possible to relate to a city the way we're used to relating to nature — or as we imagine we could relate to unspoiled wilderness," he said.
But officials and longtime river advocates say people can't plant wherever they want, and that guerrilla actors have the potential to do more harm than good.
"Even small changes can affect water quality, habitat, and safety downstream," said Ben Orbison, a spokesman for Friends of the LA River, an advocacy group focused on revitalization efforts, including cleanups along the waterway. "Restoration is incredibly important, but works best when guided by ecology and collaboration," with local and federal agencies to prioritize safety, he added.
Chief among the concerns is flooding.
"If you have rocks, if you have vegetation, if you have other things that slow the water down then it builds up faster. That's where you get the overtopping of the channel," said Ben Harris, an attorney with Los Angeles Waterkeeper, an environmental watchdog group.
The whole reason the Los Angeles River became a concrete straightjacket was to prevent a repeat of the city's devastating floods in the 1930s. The Army Corps of Engineers channelized and paved the once-meandering river. The roughly 51-mile channel continues to serve as a hydro-highway shuttling stormwater runoff from the mountains to the sea.
Generally, local officials and river advocates are far ahead of Rosenberg in revitalizing the channel. In recent years, the city has built several projects under a master plan designed to resurrect some of the river's natural habitat and expand public access. But progress is slow. Legal roadblocks and budget constraints have delayed the implementation of many proposals.
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Beyond the bike paths and trails lining the waterway, the efforts are most visible in parts of the river where the soil was left unpaved. Willows, egrets and frogs populate soft-bottom sections where springs and a high water table would reject a concrete casing. And, upstream from Rosenberg's wetland, there's a plan in the works to build what's essentially a larger, permanent version of the artist's project. Long before Rosenberg plunked his first rock into its waters, the city adopted a plan to turn an 11-mile section of the river into a wetland to allow the safe passage of salmon.
Still, some city staff give guerrilla artists a lot of credit for laying the groundwork.
"The biggest shift points in the river's history were made, in my opinion, not necessarily the legal way," said Kat Superfisky, an urban ecologist with the city, but from "the community advocate, artist, guerrilla kind of efforts."
'He's onto something'
On social media, Rosenberg shares his art with a wider audience than was made available to his artist-activist predecessors. People curious about his project have reached out to him, asking how they can help support it. He's invited them to join him on his visits to the wetland, where he's put them to work. Others have taken issue with Rosenberg's accommodation of an invasive plant species in his wetland. It's mostly populated by Goodding's willow, a native species, and creeping water primrose, a non-native invasive. Those non-native plants tend to crowd out native habitat, drink more water and lead to increased use of toxic pesticides.
Some people accustomed to reading the river's currents say the wetland will be gone before it can cause any lasting harm to the river. In the likely event of a heavy rain, the rising tide in the river channel could wipe out the wetland, washing it into the ocean.
From an ecological standpoint, Superfisky says "he's onto something," in terms of thinking about how to recreate conditions found in a natural, sprawling river using the impractical medium he's given.
The channel functions like a straight, unobstructed tube, she said. But the placement of rocks allow sediment buildup and produce varied flow patterns — much like grooves in braiding streams — to set up stiller pockets where wildlife can thrive.
But it all falls apart if he's not accounting for flood risk, the ecologist said.
Harris, of the watchdog LA Waterkeeper, thinks flood management and ecological values can coexist in a concrete channel.
Removing the concrete would open up more possibilities, he said, adding that there are "a variety of nature-based solutions" for the channel that support flood management.
But an overhaul of the existing concrete flood management system would also require big shifts in mindset.
"It's kind of a scary thought," he said. "If you imagine being a policymaker in government and you're trying to do that, you have to turn things on its head."
The Army Corps of Engineers has not responded to requests for comment. According to its website, the agency works to clear vegetation it warns can clog the channel and hamper flood control. But the agency has recently prioritized the removal of non-native species due to lack of funding, the site notes.
"They probably would just talk to him and explain rather than prosecute anything, or they might just go in and take it away," said Felicia Marcus, a fellow at Stanford University's Water in the West program and a former head of the city of Los Angeles' public works department.
Rosenberg says he understands the consequences.
"If they throw a book at me, it'll be quite a big book, but I'm at the point where that's less urgent to me than making art that obviously deserves to get made," he said.
Guerrillas lay the groundwork to rewrite the rules
Artists have long exploited that legal gray area around what's considered public land.
Historically, it was the late Lewis MacAdams, a poet and activist, whose guerrilla tactics expanded public access to the LA River. In 1985, MacAdams and friends cut open a fence blocking its entry and declared the river open to the people.
Through Friends of the LA River, the advocacy group he founded, MacAdams made sure the city wouldn't forget the river that birthed it. He promoted it as a resource that people should protect, restore and enjoy.
During a meeting with the county, as MacAdams told it, whenever the head of the public works department referred to the waterway as a "flood control channel," he would shoot back with "river." In 2008, kayakers carried the baton, when writer George Wolfe led a scofflaw fleet of paddlers down the entire waterway to prove that it was "navigable waters" so it could keep its Clean Water Act protections. Two years later, the Environmental Protection Agency agreed with what MacAdams had started and designated the river as navigable.
"He didn't know jack doodle scratch about the river or river ecosystems at that time. He led with his artistic passion," Superfisky said. "But then, my golly, he is the one guy that really got us to start calling it a river again."
Superfisky says Rosenberg is having his "Lewis MacAdams moment."
Knowing his wetland experiment could wash away in an instant, Rosenberg said he feels there's some wiggle room to experiment and make mistakes.
Rosenberg acknowledges the dangers that can spring from an uneducated approach. "I wouldn't push back on someone calling it reckless, to be honest," he said.
But he's more focused on the good he says can come from "vigorous action." He says that, among his millennial peers and younger generations, "a sense of attainability and agency" is lacking when it comes to helping chip away at big-picture issues like climate change.
He's aware that there are legal avenues available to produce ecological art. He appreciates that artist Lauren Bon, for example, has secured more than 70 permits as part of an ongoing project to divert water from the river that could irrigate a state park nearby. But Rosenberg thinks there's room for some freewheeling.
"Maybe it's not about waiting for permits or even about waiting to feel like you've mastered the material," he said. "There's a long history in ecological actions of perfect being an argument against the good happening at all."
Nature bats last
On a recent Saturday evening, during one of his public tours, Rosenberg handed out scythes and an agenda to whack away the invasive plants.
Allie Baron, a lifelong LA resident, brought her two sons with her after reaching out to Rosenberg on Instagram.
As she gleefully tore out a creeping primrose, the 36-year-old said, "All I can do is try to make my community better and make the river pretty. You do what you can to try to restore life to things that need help."
Caught in the wetland brush was a blue rubber bullet — just like the ones LAPD officers had deployed during the anti-ICE protests held in downtown LA this summer, over immigration raids.
"One of the cool things about a structure like this is that it's trapping that stuff," Rosenberg said. "The rubber bullet was here and not in the ocean yet."
That and some oily sheen on the watery patch of willows were another reminder of the intensely urban environment.
Later, the guerrilla group witnessed a hawk snatch its dinner from the water.
A few days after that, the forecast from river pundits proved accurate. It rained, filling the channel with a fast-moving current.
"The garden is gone," Rosenberg said.
He says he'll start gardening again in the spring.
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