Some things in life are best lingered over: a good meal, a glass of wine, a hot bubble bath. But the list of slow-laners includes less sensual candidates, too, such as urban runoff—the grease, oil, pesticides, sediment, and other pollutants flooded into our waterways in storms or hosed down the drain when your neighbor washes his car.
We used to think that we should get that water out of sight as quickly as possible; rather than flooding streets, send it off to the bay lickety-split. But now we know that the gunk in that runoff causes problems for everyone, especially fish. Take copper, leaching from worn brake pad linings, roofing materials, algaecides, and fungicides. Copper can cause salmon to lose their sense of smell, so they aren’t as alert to the presence of predators or able to find their natal stream. Some pesticides have the same effect.
So how do we deal with stormwater? Rechanneling it into our aging sewer systems is not an option. The problem only gets worse as we add impervious surfaces with parking lots and new housing. A recent visit to Seattle convinced me that there is a better way.
Using a revolutionary series of “natural drainage systems,” Seattle is attempting to detain and slow stormwater by trying to mimic the forest floor and pasture that once covered its landscape. Bit by bit, the city rips out pavement and pipes in suburban and urban neighborhoods, replacing concrete and asphalt with swales, rain gardens, and other soft surfaces.
California is starting to think in this direction: The state and regional water boards, the agencies with jurisdiction over water quality in the state’s streams, rivers, and bay, have begun requiring large new developments to capture most of their runoff on-site with grassy swales and porous pavement. But a lot of urban runoff comes from cities that are already built-out—San Francisco, Berkeley, Oakland, Richmond, to name just a few culprits. Although the Bay Area has been a leader in restoring urban streams, when it comes to retrofitting older cities with greener “pipes,” it is far behind the Pacific Northwest and elsewhere in the US and around the world.
Seattle’s first project, called SEA Street (for Street Edge Alternative Street) was put in the ground in 2000 in an older neighborhood northwest of downtown. The city’s transportation and public utilities departments worked with neighbors to replace an old “unimproved” gutter and ditch stormwater system with a series of connected, vegetated swales. The swales resemble the understory of a Pacific Northwest forest. “We’re trying to make an urbanized environment think like it’s still forested,” says Bob Spencer, the city’s Creek Steward. The ground is soft and covered with leaf litter; trees and shrubs glisten in the damp air. Most of the vegetation is native, but some drought-tolerant non-natives are included; neighbors were given a range of choices. Looking at other streets nearby, I can see that SEA Street (aka 2nd Avenue NW between 120th and 119th streets), was previously an “anywhere USA” older suburb. SEA Street now has a vivid sense of place, and songbirds and butterflies flit among the shrubs and trees.
“People who didn’t even know each other before come out of their houses and talk to each other now,” says Spencer. He helps organize occasional “mulch” parties to keep down weeds—the neighbors took over maintenance of the swales after the first three years. Many of them have incorporated the swales into their own gardens so that the swales look like an extension of their own yards—but a little wilder. Another benefit is slower traffic—the curvy, narrower street discourages speeding. Spencer tells me foot traffic has quadrupled. As if to validate his statement, a jogger trots by, followed by a woman pushing a baby carriage and a teenager walking his dog.
Fire trucks gain access via flat, jumpable curbs. The narrower, curved street means that less pavement can be used, says the city’s Jim Johnson. The project cost $850,000 and was funded through the city’s stormwater drainage fees. Most importantly, SEA Street led to several similar projects on a larger scale, and to huge public awareness. I ask Kevin Olson, who lives on the street, his understanding of the swales’ function. “They hold and slow down the stormwater so it doesn’t race into Pipers’ Creek and hurt the salmon,” he replies. Recent studies by the University of Washington confirm Olson: the swales are reducing runoff from two-year storms (storms that occur on average every two years and do the most damage to local creeks) by 99 percent.
Two years following SEA Street, the city ripped out four blocks of a ditch and culvert system a few blocks to the south and replaced it with a series of vegetated pools that stair-step down a fairly steep hill. This project, known as 110th Cascade, drains 21 acres of the Pipers Creek watershed. The next project, Broadview Green Grid, is larger still, draining 32 acres of the Pipers Creek watershed. Encompassing 15 city blocks and completed in 2004 at a cost of $5.1 million funded by drainage fees, it built upon what was learned at SEA Street and 110th Cascade. It incorporates swales on the north-south oriented streets and cascade step pools at the east-west boundary streets. Last October, another similarly sized project—called Pinehurst Green Grid—was put in the ground.
Seattle is also going natural in neighborhoods with straight, wide streets and conventional curbs. The first phase of the largest such project to date has just been completed—redevelopment of High Point, 130 acres of World War II housing south of downtown Seattle. The project—a collaboration among the Seattle Housing Authority, Seattle Public Utilities, and other city agencies—followed the city’s new low impact development guidelines, using porous pavement, disconnected downspouts, rain gardens, and swales; existing large trees were saved. But its most impressive feature is the series of vegetated swales—modeled after SEA Street but straighter since they run along traditional streets—between the sidewalk and street. “The idea here was to fit natural drainage systems into a new urbanist framework,” says landscape architect Peg Staeheli, who designed the swales.
Even downtown, stormwater gets a nod. With help from a one percent art tax, several stormwater treatment “installations” were put in a few years ago. One is a 10-foot-high, 6-foot diameter cistern that takes roof runoff from the downspout and stores rainwater that can later be used for landscape irrigation. Another is a series of “cistern steps,” adjacent to a downtown community garden called P-Patch. A series of terraced water gardens follows a series of pedestrian steps. Rain and runoff flow from one garden to the next (at each retained for awhile) before flowing into a small jade pool at the bottom of the hill. Part of the idea behind this project, says Staeheli, was to reintroduce the concept of the hydrologic cycle to city dwellers.
If our neighbors to the north can get on board with stormwater, why does the Bay Area and most of the rest of the state lag so far behind? We require that sprawling new developments treat their runoff on-site, but older urban areas—most of our cities—seem to have been forgotten. I posed this question to Shin Rae Lee of the San Francisco Bay Regional Water Quality Control Board.
Lee says that improving stormwater runoff is a priority for her agency but that it’s hard to make things happen here. “When we first issued our stormwater permit [to cities] to deal with new and redevelopment in 2003, this was such a big issue. We realized we cannot touch existing neighborhoods, just go in and say ‘fix it,'” says Lee. Her agency has tried to be flexible, and when a site is being redeveloped, she says, it will often allow developers to retrofit “the low hanging fruit,” such as install a stormwater swale in a nearby parking lot, for example, instead of on the site being developed. But more often, she says, cities argue against doing anything at all. “The 2003 requirements just became effective,” she adds. “We gave them a schedule for planners to be trained, for contractors and developers to be educated, to slowly bring them on board.” In other words, cities and developers leaned on the board to get a four-year extension.
Lee wishes local city and flood control agencies would realize that if they would use natural biofiltration systems such as swales, they might slow runoff and avoid widening creeks and turning them into ugly flood control channels. Part of the problem, says Lee, is that her agency’s authority over the cities is indirect and limited. The regional board is focusing now on a more stringent creek protection policy that will keep development farther from creek banks, which should lesson impacts. “We do have control over development close to creeks, so we’re trying to tie that to stormwater runoff to protect the creeks,” says Lee.
Another perceived obstacle in California, she points out, is that Prop 218, passed in 1996, required that any increase in stormwater fees be approved by two-thirds of California’s voters. Yet, she adds, several bond measures recently passed here contain money for stormwater projects, and cities, counties, and others can apply under a competitive grants program. “We need to push people to think in a more integrated creative way, to put stormwater into the grants,” says Lee. “If you do a project, it should serve multiple objectives.” Lee hopes that with better public awareness about climate change and sea level rise and the impacts they could have on storms and flows, that more cities, counties, and developers will want to do more about stormwater.
I ask Greg Gearheart, a stormwater engineer with the State Water Resources Control Board (the next level above the nine regional boards) the same question I posed to Lee. Gearheart points out that while California is ahead of other states in restoring streams and rivers, the state—and the regional water boards—may need to push harder to get local agencies to do something about stormwater. “It took a series of enforcement actions to get San Francisco to finally realize that it was in their interest to treat stormwater,” he says. Although San Francisco has not yet implemented many innovative stormwater projects, it employs a full-time staff person who is actively seeking opportunities for pilot projects.
Gearheart says California has been more focused on educating the public about not polluting downstream—stenciling storm drains, for instance, and going after industry polluters—than on looking upstream and trying to intercept and treat stormwater throughout the entire watershed. What’s sad about that is that in many of our urban areas, where creeks are underground, people have no clue about where their stormwater is going. “It means that people don’t get that there was once a natural system before they moved there,” says Gearheart, who thinks visible stormwater treatment projects—like Seattle’s swales and Portland’s rain gardens—educate people who live in cities. “Subtle landscape features are hard to understand in the first place. It’s hard to get to ‘what used to be here?’, but stormwater projects like swales and rain gardens could help with that,” he says. “California gets hung up on the big icons—the salmon in the north; the beaches in Southern California.” But, as Seattle has shown, sometimes little, slow, and green can go a long way.