Los Angeles, CA, is a city famous for its pavement. What other city lauds a mere concrete slab as a notable tourist attraction? However, apart from the landmark Hollywood Walk of Fame, life, like the concrete, can be a little harder. Mile upon mile of freeways and boulevards, punctuated by parking lots and service facilities, sprawl over the region, distancing residents from the pleasures and benefits only nature can provide.
The Needs of the People
In his successful mayoral bid, Antonio Villaraigosa pointed to the need for green space as an important campaign issue. On his campaign Web site, he noted that Los Angeles (L.A.) has “the least accessible park system of any major city in America. Only 30% of Angelenos live within a quarter of a mile of a park, compared with between 80% and 90% in Boston [MA] and New York. Here in Los Angeles, more than 700,000 children do not live within walking distance of a park.”
Jan Perry says before she was elected to the Los Angeles City Council, she would ride through South Los Angeles with a good friend, looking for ways to improve the district. Five miles south of downtown and a half-mile east of the I-110 freeway, South Los Angeles is a community of single-family homes, duplexes, mid-rise apartments, and light industrial development. But Perry noticed that one thing was absent–nature. With the verdant hills in the distance obscured by haze, and the coastal beaches inaccessible to many residents for lack of transportation, Perry says it became clear to her that in this area, “There just weren’t enough parks to meet the needs of the population.”
Until recently, public works departments across the country have shown a similar affinity for pavement, as have the road builders and developers. Sean Vargas, senior project manager with Psomas Engineering, says the rationale “was basically flood control. You were just trying to prevent a capital flood from causing damage to public health and safety. They were just draining these very highly urbanized watersheds to paved channels and discharging directly into the ocean, with no treatment.” The same was true in Los Angeles.
Thus, untreated stormwater, carrying with it metals from the roadways, nutrients, bacteria, and other contaminants, flowed right to the oceanfront beaches, making the region’s parks even less safe and less accessible.
Los Angeles was saddled with two major quality of life problems: a critical parks deficit within the city, and severely polluted stormwater flowing from city streets and storm drains into the rivers and beaches.
Though the wetland at Hawkins Park treats only the runoff from the park’s 4.5-acre footprint, Perry says that as a demonstration project it performs a role in educating the community on water-quality issues while building public support for stormwater initiatives. It has also enabled the technical leap to the South Los Angeles Wetlands Park project, which, by contrast, will treat not only the runoff from its own 9-acre footprint, but also a portion of the runoff from the 525-acre tributary watershed of the surrounding community.
Drilling Down
Upon the approval of the Citizens Oversight Advisory Committee, the concept reports completed by the city were forwarded to Psomas Engineering to begin preliminary design work.
Vargas says the firm’s experience with bond-funded sustainability programs allowed it to “step in seamlessly and act as an extension of the city for stormwater-related projects.” This arrangement, he says, “allows the firm to do anything from administrative support to construction management–basically whatever they need us to do, they can hire us as experts.”
The obvious place to start was to go out and survey the site. “It was a pretty involved effort,” says Vargas–which included geotechnical exploration, environmental exploration, topographic surveys, boundary surveys, and title report research–“just so we could know everything that we could know about the site.”
He says the utility mapping effort was a critical early piece that had to be done in advance of some of the geotechnical work, “because you don’t want to be drilling down and breaking a utility line.”
The use of the site as a transit facility dates back to 1901, when it serviced the city’s fleet of trolley cars. These deep historical roots posed a challenge for the site survey team. “For something that was built in the last 10 years or so, you would have the “˜as built’ documentation to refer to,” says Vargas. “You could pull up the drawings, and they would indicate to you exactly how it was built. You might also survey manhole lids and handhole pull-boxes, to correlate the recorded plans with what is actually on the ground.” But in this case, because of the age of the installation, there was very little information available.
However, he says, “Invariably, there’s somebody on site who’s been there for 30 years and knows where all the buried bodies are.” And, he adds, thanks to the close partnership between the MTA, the council members’ office, and the other members of the task force, “They knew exactly who to send us to. In fact, he was out there waiting for us when we showed up.”
Besides the lack of information, the site presented a few other drawbacks. “There were rail spurs, because they’ve been doing maintenance in that area,” says Vargas, which could have resulted in surface contamination. He anticipates there will a need for be some remediation, particularly “taking out some of the soils that may be adjacent to some of the clarifiers.”
He also notes, “There’s always that little twinge, when you’re dealing with a brownfield site–it’s the unknowns that could get you. That’s why we’ve done all this exhaustive preliminary design report work, to try and know as much about that as we can.”
To cap off its investigations, Psomas brought in a subsurface detection unit to probe the underground terrain and validate what it had learned. According to Vargas, the survey uncovered nothing particularly alarming. Nonetheless, as part of the project’s collaborative arrangement, the MTA committed $900,000 for site remediation and cleanup. Council member Perry says, however, she is hopeful that some of the remaining rail artifacts could be preserved to find a second life as historic design elements for the future park, while some of the antiquated structures might be rehabbed for use as public space.
Artist’s rendition of the South Los Angeles Wetland Park
The park will feature trails, boardwalks, and observation decks.
Monitoring the storm drain at San Pedro Street adjacent to the Wetland Park project, Psomas was able to confirm, during a particularly dry season of September 2007, an average flow of approximately 14,000 gallons per day (gpd), a quantity of water that Vargas says would be sufficient to sustain the wetland habitat during periods between rains.
Target Funding
In addition to the $900,000 the MTA plans to contribute for site remediation, Psomas estimates the total project cost at about $24 million. Assembling this funding, Perry says, has been the toughest challenge in putting together the wetland project.
A recent bond issue, Proposition O, is expected to provide $8 million, but the balance must be stitched together from wherever the money can be found. “Some of it’s grant money, some of it’s brownfields money; it just depends,” says Perry.
According to John Saldin, senior civil engineer with the Los Angeles Department of Public Works, the initiative is being funded via numerous sources, including a Baykeeper settlement; Proposition K, which targets park improvements through a competitive grant process; Proposition 50, which focuses on protecting drinking water supplies; and Proposition 40, a measure broadly targeting air, water, parks, and resource protection.
As project manager for the South Los Angeles Wetlands, Saldin says the cooperation between various agencies involved in the project has been key in overcoming the funding hurdles. “We interact with a number of other groups in the city. They are the grant holders, but we provide them with the documentation to get the grant money.”
But according to Vargas, Proposition O has been the key measure facilitating the effort. Had it not been for the passage of Proposition O in 2004, authorizing the city to issue up to $500 million in bonds for “green stormwater solutions,” Vargas says, getting the wetlands project started “would have been an uphill battle.”
He explains, “I’m working on a number of projects for other municipalities, for nonprofits that are real advocates for sustainable stormwater solutions, and without a measure like Proposition O, the money is really not there. You’ve got to get people excited about it generally to get a donor.
“Some of the backing that the council member wields is the ability to round up the funding and get the project going,” says Saldin. “It takes some coordination, but once it’s all lined up and each group knows what it needs to do, then we just do it.”
And they are making progress. With the property transfer yet to be finalized, and with time still to go before the Bureau of Sanitation finally takes occupancy of the site, design work is already more than 50% complete.
Bottom Feeders and Larvae Eaters
As specified in Psomas’s preliminary design report, the wetlands will comprise three individual cells covering a total area of between 4 and 4.5 acres. According to the report, the division of a constructed wetland into individual cells increases the treatment efficiency and may also allow for easier repairs, cleanout, and general maintenance. At high water level, the total volume is 7.5 acre-feet. To prevent groundwater infiltration, the treatment area will be contained within a clay liner.
Although the facility will be designed to manage an average baseflow of 80,000 gpd, to achieve maximum treatment, Vargas says, “We’re putting in systems to divert the entire dry-weather flow into the wetlands. We’re breaking into the pipe, and all of that runoff that’s running in the very bottom of the pipe–the very low-flow–we’re diverting to the wetland.”
Public access will allow people to learn about native habitat and species.
The new 9-acre park will treat runoff from more than 500 acres of the surrounding community.
During this low-flow regime, water captured from the storm drain will pass through a hydraulic separator to remove grease and particulates. The pretreated water will then be pumped up and discharged at the headworks of the wetland.
During the high-flow regime surrounding a storm event, a larger pump and diversion system will direct a flow of up to 16 cubic feet per second to the headworks, filling out the wetland to its maximum extent of 4 to 4.5 acres to achieve a treatment volume of 2.1 acre-feet.
“We can divert water very quickly out of the storm drain and get the most polluted water, the first flush, into the wetland very quickly, and then we can shut the pumps down and let the wetland’s biological process take its time as that water is slowly discharged,” says Vargas.
After passing through the wetland with a residency period of between 50 and 120 days, the water will exit the wetland at the western portion of cell 3 through an outlet structure and discharge into the storm drain main in San Pedro Street.
“The way the hydrology of the basin works, currently, all of the water that we will be treating onsite would have bypassed the site, because it’s already in the storm drain,” says Vargas. With the new design, however, “We take out as much as we can and fill the wetland. That gives us our treatment volume; when that is full, everything else goes by like it did before. You don’t want to wash your wetland out.
“After about 6 inches have discharged back into the storm drain,” continues Vargas, “the pumps will be reactivated, filling that portion back up” with the remaining storm flow.
Vector control, of course, is an important design consideration for any constructed wetland. Saldin says keeping the water moving is the key to controlling pests such as mosquitoes. “That is a question of maintaining drainage inflow and outflow so that there is never a condition that the water would be stagnant.”
According to Saldin, 72 hours is the longest period of time the water can remain standing before there is the risk of a vector problem. “This design would not allow for the flow to stop for anything near that long,” he says.
Tam says vector control experts, whom he consulted, confirmed the design would meet mosquito control requirements. Nevertheless, Tam says, “We’ll probably take the precaution of putting in mosquito fish to help out by eating the larvae.”
The upland areas will be landscaped with “native high-desert type vegetation that will require about a third of the irrigation that would normally be required by a public park with turfed lawns,” says Vargas, and, as a result, the park’s irrigation requirements will be minimal.
Psomas’s intense planning effort leaves no detail to chance, be it aesthetic or operational. The design even specifies white, weather-resistant “split-rail style” fencing around the wetland itself, to provide a necessary modicum of safety while maintaining the rustic flavor desired by the community. And, Vargas says, in keeping with the city council’s request not to have another chain link fence imposed upon the neighborhood, the park will be bounded by an “architecturally substantial” tubular steel fence. “That’s the level of detail they wanted to really make sure it was a great facility,” says Vargas.
“It’s incredibly complex the way that this has come together, with different funding sources and different milestones that the project has to hit in order to retain that funding,” says Vargas. “It’s going to be done in segments in order to get the demolition to happen, the remediation happening, and the construction to begin, while the rest of it is being demolished, remediated, and constructed.”
The completed park is slated to open by late 2010.
But the partners plan to continue the collaborative effort beyond the ribbon cutting. In accord with negotiations settled during the early stages of planning, management responsibilities for the park will be split between two of the partner agencies. The wetlands portions of the park will be maintained by Bureau of Sanitation, while the upland portions will be managed by the Bureau of Parks and Recreation.
Vargas envisions the finished park with such features as a rock garden outdoor classroom, boardwalks, and observation decks. Adding to this list, Tam foresees trails and “picnic areas consistent with all of the other wetland park development that’s going on throughout the country.” Further, he believes the park “can serve as a public education tool.”
Perry says the wetland concept has already proven itself in this community, on a smaller scale, at Augustus Hawkins Park. During the 18 months of construction, she says there was one surprise: “How quickly the plants grew. It looks like it’s been there forever now. It’s extremely attractive.”
“It was instructive, in that you see what was successful, and what was not, both from the wetlands standpoint, and from the appurtenant facilities,” says Vargas. “We were able to learn some good things about how the wetland park wanted to behave locally.”
“When I was there, I was amazed at how many tours they did,” says Tam. “They actually bring in schoolchildren and community groups to look at what’s there.
“You would not expect to see anything like that in Los Angeles,” he continues. “That’s the perspective you have–and that’s why we’re trying to change that a little bit here.”
Just a Beginning
Perry says these two wetlands parks will form part of a chain in South Los Angeles “to remediate and remove contaminants in a natural and holistic way that would benefit people directly.”
And, Perry says, it’s good policy. “As a city we have matured; we understand that wetlands assist us in dealing with urban runoff. When we capture stormwater flow, there’s an opportunity to clean it.
“There are a lot of layers to this park,” she adds. “I think it’s a wonderful opportunity for young people to learn about ecosystems, to learn about native habitat and native species, an opportunity to take a property that may have been blighted in the past and turn it into something that is hands-on and friendly, that can not only provide an aesthetic benefit but also a community benefit.”
Perry makes perhaps the strongest case for the South Los Angeles Wetland Park by simply describing an afternoon visit to the wetland shores of Augustus Hawkins Park. “I’ve personally observed herons and egrets and shore birds that live in the vegetation along the water,” she says. “And it’s pretty amazing. The kids really love it. We have lots of pollywogs, and all sorts of things, swimming in the water. If you go down there at four o’clock in the afternoon you can really hear the birds in a big way.
“It has a calming effect,” continues Perry. “It’s a different kind of park. It’s not the kind of park where you go and they have soccer, baseball, and all those types of things. It’s a passive park where people come in, and they have picnics, sit down, relax, and watch their kids while they ride their bicycles on the path. People really seem to be happy and peaceful when they’re in there.
“People really enjoy that park, and to know that another one is coming that’s bigger and better–that’s something people seem pretty happy about.”
