Spokane, WA, is yet another American city plagued with combined sewer overflows (CSOs). Its older infrastructure is inadequate to keep up with its growth. During heavy storms, neighborhoods with combined storm and sanitary sewers experience overflows that dump untreated water into the Spokane River.
The city of Spokane spent about $200 million over a dozen years upgrading its infrastructure to reduce CSOs. Officials had developed a plan to spend another $300 million, but they scrapped that plan in favor of a different approach. That’s because, in Spokane, it’s all about a cleaner Spokane River and the sooner, the better.
The Spokane River, a tributary of the Columbia River, runs for 112 miles through northern Idaho and eastern Washington. Three of the river’s seven dams—Upriver, Upper Falls, and Monroe Street—are in its namesake city.
In the downtown area the river flows over the Spokane Falls. Other tributaries join the river on the western side of the city. The river follows the southern edge of the Selkirk Mountains and the Spokane Indian Reservation. It joins the Columbia River at the site of historic Fort Spokane.
Managing stormwater runoff is critical to improving the quality of water in the Spokane River. Years ago, mining operations in Idaho sent hazardous metals down the river’s course to impair its waters. In more recent years PCBs, or polychlorinated biphenyls, have become the chief pollutant.
Spokane’s city council approved the new plan in 2014. The city changed its course for managing stormwater. Now it set sail with a very different strategy called the Integrated Clean Water Plan.
“One thing that makes us unique [in stormwater management] is the pursuit of an integrated approach. We’re doing it with no consent decree and doing it on a voluntary basis,” says Rick Romero, utilities director for the City of Spokane until his recent retirement.
Various factors led to the creation of Spokane’s new approach to managing its stormwater. Romero says, “It was a convergence of several things: new leadership at the city, which happened to come with a lot of pressure put on the EPA from the Conference of US Mayors [whose members were] facing large price tags for dealing with CSOs.”
He notes that another factor was “my going into Public Works in 2012” from a background in business management at a university.
When he attended an EPA conference with newly elected Spokane Mayor David Condon, the two new Spokane officials were convinced that “we’ve got to find a smarter way to do this, and the integrated way is best.”
When the mayor took office, on his desk were two contracts to sign—contracts, Romero says, “that would have committed us to gray solutions. We said ‘Let’s sit back and rethink this.'”
He adds, “We created a team of five or six members from the city and five or six members from our regulators, the Washington State Department of Ecology.”
The team took a year to develop the new plan for Spokane. “We had three goals that we established out of the gate, and we never deviated from them,” says Romero.
Unlike many other cities with CSO problems, “We weren’t looking to buy time. Buying time was more the enemy than it was the ally,” he notes.
The first goal was funding projects “that had the greatest impact on [reducing] pollution to the river. Second, we realized that big gray tanks probably were not the most cost effective, so we had to look for innovative ways to bring the price [of projects] down.”
With the second goal in mind, “we had to be both environmentally responsible for our city and financially responsible for our city.”
The third goal was taking “a holistic, integrated approach with all of our infrastructure in the city. We had to look at everything that impacted stormwater or might mitigate stormwater,” says Romero.
“We had no idea how far we could go with integrating things, but it ended up being the key. We’re getting better parks, better streets, and better stormwater management.”
Romero calls the new Integrated Clean Water Plan “a game changer for the city.” To develop this innovative plan, he says, “First we had to look at risk—environmental risk and business risk. The plan we inherited in 2012 called for 31 million gallons of gray storage infrastructure for CSO [abating] projects. The cost would have been $320 million.”
Noting that many people assume Spokane has the same rainy climate that Seattle does, Romero says, “We’re 300 miles from Seattle, but in terms of weather patterns, it might as well be 3,000 miles. We have much more snow and occasional intense storms.”
With the local weather in mind, he says, “We graphed our overflow and storm events. The most significant events, every three or four years, were rain that fell on snow. We had to ask ourselves, ‘What are we getting for [paying for] that 31 million gallons of stormwater storage?'”
Spokane’s new team considered what risk tolerance it was willing to accept. “With 14 million gallons of storage capacity we could [handle] a two-year stormwater event; 99.87% of the time that extra 17 million gallon space would be empty, so was it worth $150 million extra to get to zero risk?” says Romero.
Because Spokane’s state regulatory partner agencies allow for one CSO event per year, Spokane’s team “designed everything around a two-year storm event,” he says. “We sized everything according to basin and outflow data collected over 10 years.”
The next step was explaining the reasons for the team’s design standard to environmental interest groups “so that they understood what choices we were making and why,” says Romero. “We did so much public outreach, and it paid huge dividends. People became advocates instead of objectors. We asked them, ‘For an additional 1.3% risk [reduction], are you willing to pay an additional $150 million?'”
As if those figures were not convincing enough of the value of the new approach, there was the 2011 rate study to compare with new projected rates. The study called for double-digit rate increases for each of the next three or four years, then a drop to single-digit increases, he says.
Spokane River
“We committed to holding increases to 2.9% per year for at least the next three to five years. That’s a huge rate reduction to the citizens, and a much quicker solution to clean up the river at a much more cost-effective rate,” says Romero.
The new Integrated Clean Water Plan increases cooperation between various departments within Spokane’s city government. As an example, Romero cites the good working relationship between the parks and the utilities departments.
“The majority of our stormwater storage tanks are on parks department property, below ground. “We pay them a lease, but it’s cheaper than using private land. We give the parks either parking or park-like amenities.”
Critical to making the new integrated plan a success was the creation of an Integrated Capital Department.
“We manage it with our own engineers,” says Romero, adding that he was fortunate to have “the most talented engineers. They’ve embraced this plan and they’ve been able to find creative ways to maximize pollution reduction and minimize cost by bringing it in house.”
Also essential to the plan’s success was moving city staff (chiefly engineers) into the same building. “People started to look at themselves as city engineers who solve the city’s problems, not as departmental engineers who protect [the interests of] one department,” says Romero.
“You’d think it was a line of authority problem, but it was the [separate] money accounts. I was blessed with really smart, good people, and when we took away having to worry about their own departments’ money, they began working together,” he adds.
Spokane’s mayor and city council had to approve the new plan. The water and wastewater departments’ funds were combined by themselves. Other departments were able to share by exchanging benefits.
“Streets were the key to all of this,” says Romero. “When we downsize our stormwater storage tanks, we’re taking some risk. Every time we touch a street now we make a commitment to take stormwater off of that street.”
In the past, he notes, “Every department did its own work. Streets were torn up repeatedly. Now we do only full-scale street projects—bike lanes, repaving, permeable pavers, stormwater features, utility line upgrades. We tackle a street holistically, with careful planning and sequence of operation, so that a street is torn up only once.”
There is no doubt that an overwhelming majority of Spokane’s resident approve of the new Integrated Clean Water Plan. In November 2014, 78% of the voters approved a 20-year street levy of $5 million. The city would match this levy and then use the total to secure more funding from state and federal sources.
Storm Gardens
What residents of other parts of the US call rain gardens, Spokane citizens term storm gardens. That’s because runoff derives from both rain and snow, a total of about 16 inches of precipitation annually.
The nonprofit environmental organization The Lands Council works to educate Spokane residents about stormwater issues. The group actively promotes storm gardens and has partnered with the city on a pilot storm garden project in the Shadle Park neighborhood. This neighborhood has had to cope with CSOs for years. Fortunately it has the advantage of having soils that infiltrate runoff well.
The storm gardens between the sidewalk and street feature native plants and biochar—highly porous activated carbon, produced from crop and seed-milling residue—that has been shown to be effective at removing PCBs and heavy metals from stormwater.
Amanda Parrish, The Lands Council’s watershed program director, says homeowners are enthusiastic about the storm gardens and that the native plants have done well. They include Idaho fescue, camas, red osier dogwood, purple sage, and scarlet gilia.
“We went door to door in the Shadle Park neighborhood, not just to show the city that people were interested in the project, but to educate people about what stormwater does,” recalls Parrish. “We have a good working relationship with the city and we’re a trusted source of stormwater information.”
She notes, “We used two types of biochar—a wood chip–based one from western Washington and a Kentucky Bluegrass–based one from eastern Washington.” Both types of biochar are working well. “The big question is how long before the biochar reaches some point of saturation and needs to be replaced,” she adds.
Construction on the three storm gardens was completed in November 2014, and the plants were installed in the spring of 2015. Two of the gardens measure about 6 feet by 40 feet, and the third one is 6 feet by 120 feet. Together they handle 335,144 gallons of stormwater each year.
Storm garden in the Shadle Park neighborhood
“We weed and replace plants as needed now. Eventually the responsibility for maintenance will probably pass to the homeowners. If the city decides to do storm gardens on a large scale, I hope they will do maintenance twice a year,” says Parrish.
Another joint stormwater project that The Lands Council and the city are working on involves growing oyster and other types of mushroom mycelium. The mycelium, or root section, of the fungi is known to break down PCBs.
The city will collect vactor waste from within storm drains. This waste is high in PCBs. Staff members at The Lands Council will add the vactor waste to jars containing the mushroom roots and monitor how well the various fungi chemically break down the PCBs.
If the oyster mushrooms grown in the lab work as expected, Parrish says, “we’ll incorporate [the residue] into bioswales. We’ll know by the end of 2016 if the project is successful or not.”
This green strategy looks promising for removing PCB pollution from stormwater in urban areas, even on a large scale. Straw mats, easily portable, could be inoculated with the mushroom mycelium and placed where they would be most effective.
“Our philosophy is that we do things pretty low tech, based on natural processes. This is a green alternative that’s pretty progressive,” says Parrish.
The cost for this city-funded operation was a modest $50,000: $20,000 to build and equip the lab space and $30,000 for paying staff members. Parrish describes the trial of this green strategy as “a low-risk investment” that could prove to be very cost effective.
The Gateway: Lincoln Street
Romero describes Spokane’s Lincoln Street as “a gateway to our city—an attractive park-like street.”
Eleven blocks of the older residential street were a fine setting for a green stormwater management project that’s a good example of Integrated Clean Water Plan projects, even though it was done before the plan was finalized. The street itself was resurfaced, and while that work was being done a stormwater facility was installed.
The Spokane landscape architecture firm of AHBL designed the stormwater project on Lincoln Street in 2009. It was installed in 2010.
“We moved the curb out seven or eight feet toward the center of the street. There wasn’t much need for on-street parking, so we turned that into a storm garden,” says Craig Anderson, project manager and landscape architect at AHBL.
Lincoln Street is on a hill. All along the right of way are storm gardens with check dams of recycled plastic timber between them.
“Two years after installation we had a 10-year storm event,” says Anderson. “One of our engineers had his wife drive down Lincoln Street during the storm, and he watched out the car window as water entered at the top of the street. It ponded through the first couple of biocells, but at the bottom there was no ponding. All of the water had infiltrated.”
The neighborhood has silty clay soil on top of basalt—not favorable for infiltration. Anderson says, “We suspect we tapped into some fissures in the basalt. The project has performed better than expected.”
The biofiltration soil added to a depth of 18 inches was the mix developed by the Washington State Department of Ecology, a sandy loam and compost mix. Plants installed included dwarf Oregon grape, dwarf blue fescue, may night salvia, yellow day lilies, and shasta daisies.
“We put in a mix of evergreen plants and plants from a successively flowering palette so that from late spring to early fall something is blooming in the storm gardens,” says Anderson.
At the bottom of the hill an underdrain system is beneath part of the installation. It takes runoff to the pond at Cannon Hill Park.
“This was the first project of its type that the city had done. It was a steep learning curve for the engineering and design staff. It was also a learning curve on the public’s side. Some people wanted only [traditional] turf and trees,” says Anderson.
Residents had to be educated about how the storm gardens would look and be maintained and realize that their earlier perceptions were not accurate. For example, some residents confused species of Oregon grape and thought the species that grows several feet tall would be planted along the street and cause major maintenance problems.
Anderson says it took two full growing seasons for the plants to become established. “We’ve had very positive feedback from the public. The residents like how the curb extension has slowed down traffic.”
Hazel’s Creek
Hazel’s Creek Drainage and Conservation Facility is a regional stormwater management project that comprises about 10 acres of open area with native vegetation. It collects and treats stormwater in Hazel’s Creek sub-basin, which is part of the Glenrose watershed.
Once a farm (whose last owner was named Hazel), the park-like facility is located in the midst of a suburban residential neighborhood on the south side of Spokane. The soils here rest atop basalt and don’t infiltrate runoff well. However, there are paleo channels within the layers of basalt that allow runoff to filter through. Spokane requires that all new development infiltrate its stormwater onsite. Because of these paleo channels, commercial and residential development is possible on this side of the city.
Signage at Olmsted Green Park
“The city brings an alternative to the developers. They can develop more projects. They don’t have responsibility for their stormwater, but they have to pay the city a fee,” explains Romero.
Hazel’s Creek serves as a demonstration site for various low-impact-development (LID) technologies. These demo sites, placed along the walking trails and wetlands, were designed by AHBL.
Anderson says the LID features include bioinfiltration areas, mulching with different materials for comparison, pin foundations that allow shallow groundwater to pass through, areas of different plant palettes suitable for very wet or very dry conditions, and constructed and natural wetlands.
Hazel’s Creek has interpretative signage by various features. Anderson likes the additional QR code scanners that allow visitors to “get on their phones and scan to read about the history or geology or stormwater management. Unlike signs, the city can quickly change the copy at no cost.”
Earlier this spring the city announced plans to expand Hazel’s Creek. This will allow more development in the area, with stormwater flowing through more paleo channels.
Kendall Yards, the former site of railroad yards, is a housing and commercial development right on the Spokane River. This public-private partnership includes park-like open areas for infiltration and stormwater ponds. A stormwater storage tank lies beneath the park area.
Michael Terrell-Landscape Architecture designed the grounds of the 77-acre infill project.
Other green features at Kendall Yards include permeable paving with KloroStone and native plant landscaping.
Construction will begin this summer on an integrated street project on 37th Avenue. Other projects with integrated features, such as those on Havana and Sharp Avenues, are in various stages of development. Romero’s favorite project, though, is what he calls his “legacy project.”
This innovative project is now in design. Two big CSO basins adjoin the beautiful downtown Spokane Falls. “We’ll turn ordinary concrete tanks into a phenomenal public asset,” he says. One stormwater tank will be on each side of the falls, like bookends. Atop them will be park-like settings, with trailheads leading down to the river. There will be plantings, outdoor art exhibits, and other amenities. The plaza space over the 2-million-gallon tank will measure 330 feet long by 50 feet wide, great for concerts and public gatherings.
“We’ll have to close down Spokane Falls Boulevard for a year and a half, but this project will give the public multiple benefits for their money,” he says.
Romero admits that the integrated approach isn’t easy. “You have to make a bigger commitment. It’s easier for all [the departments] to do their own projects.” The major challenge is “finding ways to keep from working against ourselves on the dollar side.”
The results are worth it, though. “One construction contract saves 30 to 40% over each department running their own capital funds.” Looking ahead, Romero predicts that “over the next 20 years for stormwater management, streets, and utilities, we’ll save half a billion dollars.”