For most of the three decades Rosendo Mendez has lived in his South Los Angeles bungalow, the alley behind it had been a problem. The strip of asphalt that neighbors used to access their garages was riddled with potholes that attracted all kinds of garbage and became massive puddles whenever it rained. “A lot of water and a lot of trash,” Mendez says. Then, about 15 years ago, the city came to Mendez with a proposition: Let a team of civic engineers and landscape architects tear up the asphalt and replace it with a “green alley”: A smoothly paved corridor with brightly painted murals, new greenery, and more places to stroll. These changes, beyond making the alleys beautiful, would help drain rain away from Mendez’s and his neighbor’s homes after storms, recharge the groundwater system that would keep the neighborhood cool, and could even be used as a local water source in times of drought.
The project, built in collaboration with the Trust for Public Land, was part of a bigger vision for a network of similar infrastructure throughout the neighborhood. South L.A. has about 300 miles of alleyways — about one-third of all the alleys in the city — and due to the combination of low-lying land, paved-over surfaces, and aging sewer infrastructure, it also has the city’s second-highest rate of flooding complaints. The green alleys, once there were enough of them, could help. Mendez said yes, his neighbors did the same, and within two years, the muddy, uneven asphalt was gone. Now just beyond Mendez’s back fence is an attractive right-of-way signified by green-and-white-striped poles planted with citrus trees at each entrance. Students from the elementary school across the street help maintain the alley through regular clean-ups, and Mendez says he feels comfortable walking his dog there, even late at night.
As wave after wave of atmospheric river storms slammed the city over the last month, green alleys like Mendez’s were put to their first real test. The city received as much rainfall between the start of the rainy season in October and the end of January as it usually gets by the end of April. But as that deluge pummeled South L.A., the resulting stormwater had more opportunities to sink back into the earth: filtering through a row of permeable pavers, directing to pocket planters where creeping fig vines twirl up garage walls, or vanishing into grates labeled “drains to groundwater.” One alley even has a center-running bioswale where tiny notches along the curbs nudge water into rectangles of drought-tolerant landscaping. Mendez’s corner of the neighborhood fared well — no water issues, he said: “Right now, it’s okay.”
Before the interventions made by the city and the Trust for Public Land, the alleys were designed to flush water away using a center-running gutter, but most of what those hardscape surfaces ended up doing was transferring water to the street, where it was just as likely to encounter pothole puddles and blocked drainage on its journey downhill. But a single green alley is able to capture enough stormwater per year to store it in dry wells below the pavers where it can slowly percolate into the groundwater, says Allen Compton, founder of the landscape architecture firm SALT, which designed these alleys. (One small challenge has been maintenance related, he says: Even the permeable pavers sometimes get clogged.)
In addition to absorbing water better, the alleys also zigzag around another notable piece of green infrastructure that collects water from the neighborhood: the South L.A. Wetlands Park, a ten-acre former transit yard transformed in 2013 into a marshy lake frequented by both joggers and turtles. Compton, whose firm is at work on another batch of alleys about a mile away, says projects like this are creating a new “urban vocabulary” for L.A., putting the focus on not only water but also wildlife habitats and walking networks. “Every project we touch has some stormwater strategy to it now,” he says. This is more or less the gold standard for withstanding the extremes of California weather to come: a network of lush, green, and porous blocks that feed into what is essentially a big, beautiful sponge.
What happens in the absence of such drainage networks became frustratingly clear in the last month: Widespread flooding closed roads. Sinkholes swallowed cars. L.A.’s Union Station filled like a wading pool. (The danger of these floods is also not borne equally — L.A. County’s Black residents are 79 percent more likely to experience waist-high flooding than white residents.) There’s also a tremendous amount of water wasted: Most of the rain that falls is sent surging through the city’s over 1,000 miles of drains and channels — including the most famous one, the L.A. River — carrying a stew of plastic bags, oil slicks, dog poop, discarded antibiotics, and tiny chunks of car tires to the Pacific Ocean.
The city-as-sponge plan will take time, but L.A. is making strides: Preventing the local flooding that used to plague Mendez’s alley is a microcosm of the changes the region is trying to make to its flood-control infrastructure, only on a bigger scale — a delicate balance of collecting and storing water in reservoirs and releasing it to other facilities that allow it to infiltrate underground aquifers. The Big Tujunga Dam, for example, which prevents the northern part of L.A. from being overwhelmed by runoff from the San Gabriel Mountains, is able to divert stormwater into the nearby Tujunga Spreading Grounds, replenishing a critical groundwater reserve in the San Fernando Valley instead of flushing it out to sea. And now, like other flood-prone parts of the U.S., L.A. County is doubling down on major flood-control projects that double as parks or recreational areas, like Houston’s Buffalo Bayou and Atlanta’s Rodney Cook Sr. Park (though the best examples are still outside of the U.S.).
This is the direction L.A. needs to be moving, especially as our water sources are drying up. Officials are recognizing the importance of conserving water locally and making the region as a whole more climate-resilient. But stormwater capture projects have, historically, taken a very long time. Outreach for the green alleys in South L.A. began in 2008 with the first alley completed in 2015. Nearly a decade after the first project was permitted, a majority of the six-block area envisioned in the plan still does not have the recommended stormwater improvements. Other water improvements in the neighborhood have been just as slow. Teresa McDonald, the founder of the South L.A. organization Ultimate Restoration Unlimited, is part of a coalition doing outreach for water projects in underserved neighborhoods. The projects were eligible for funding through a 2014 state ballot proposition that allocated $7.1 billion for these updates, and McDonald wanted to ensure that money helped transform her own neighborhoods. “We wanted to get into this idea of healing our communities through water,” she says. In the end, McDonald’s work helped to get funding for two stormwater projects at an elementary school and community garden — both of which still have yet to break ground.
But other work is happening around the neighborhood; it’s just not the kind of storm-resilient transformation it so desperately needs. McDonald looks around the surrounding area where city crews are repairing streets and sidewalks to last-century standards — adding concrete, more concrete, and piles of river rocks set in concrete — without adding interventions like more trees or bioswales that the residents now know will also protect them from extreme heat and pollution from adjacent freeways, she says. It’s like the city draws up ambitious sustainability plans and puts out calls for big projects but isn’t taking its own advice to implement crucial infrastructure to prepare for its water future block by block.
Because stormwater is still erroneously classified as a waste product, its management is handled by the same department that picks up the trash. And the fact that L.A.’s stormwater interventions are mostly concentrated in places like parks or spreading grounds instead of the places where people live is largely due to the lack of coordination between agencies. The city is working on streamlining this process in the form of an interagency stormwater plan that would require better coordination with the Department of Water and Power and the Bureau of Street Services, says Michael Scaduto, senior civil engineer at the Department of Sanitation. “Wherever we can collaborate, we can make our stormwater funds go much further,” he says. “If we can find a project that they’re willing to do the paving or they’re willing to resurface, then we just bring in the stormwater funding.” More of that funding is coming, too: a 2018 L.A. County ballot measure placed a small tax on impermeable surfaces that prevent proper drainage. If homeowners replace them with infrastructure that aids in water capture — permeable pavers or drought-tolerant gardens — their tax rate goes down. The funds are then put towards 100 stormwater projects, including new green alleys in L.A. city. By Measure W’s own estimates, L.A. County’s captured stormwater could provide 70 percent of its water needs locally, yet it will take decades to achieve this goal.
Which means how the city prioritizes projects is crucial, says Melanie Winter, founder and director of The River Project. Winter envisions a new strategy in which every community gets its own neighborhood project similar in scale to the South L.A. Wetlands, but where more focus is on the city’s streets, medians, and sidewalks, which are arguably its biggest and best-distributed assets: “Every parkway becomes a habitat that recharges groundwater, mitigates flood risk, and supports street trees without potable water.” Winter’s team worked with the city to transform nearly a mile of parkway near the Tujunga Wash from a concrete median into a naturalized bioswale that opened in 2015. (Like the alleys, the process also took a long time — about five years.) The most important technology deployed here is not a complex underground cistern or even interlocking permeable pavers, says Winter, it’s those tiny notches in the curb that allow runoff from the gutter to filter over some stones and into a native-planted garden with decomposed granite and sycamore trees. These projects can cost a few thousand dollars and be completed in a matter of months. The smaller interventions have also been proven to work — the city of San Francisco reported that its bioswales helped to mitigate flooding after the recent storms — and when put to the test in a bigger storm, they can also save lives. But Winter says there’s only one median like this in all of L.A. city. “It’s probably the most cost-effective project in that vein that’s been done,” she says. “They’ve not replicated it because it’s too simple — simple scares them. Hell, nature scares them.”