City of Marysville’s focus on green infrastructure produces multiple benefits
Adam Benton, project engineer with the City of Marysville, has seen firsthand what an accumulated flow of polluted stormwater runoff looks like. Back when he worked in the city’s surface water division, he saw what happened when the first fall rainstorms hit the pavement after everything had been dry during the summer months. “You will see a plume and it’s comprised of petroleum and heavy metals from your brake calipers and every other thing that comes off your vehicle when you’re driving down the road,” he said. “That’s the visual I have in my mind when I envision what we’re doing with these projects.”
The projects Benton’s talking about are part of the City of Marysville’s focus on including elements of green infrastructure in their large-scale infrastructure and road improvement projects. This approach helps control and treat polluted stormwater runoff before it reaches Ebey Slough — part of the Snohomish River estuary — and Puget Sound.
When stormwater flows off buildings and over roads and parking lots, it can pick up chemicals, oils, and other contaminants — as Benton’s experience illustrates — and carry those pollutants into rivers, streams, lakes, and coastal waters, where it degrades water quality and damages both wildlife and habitat. Green infrastructure or low-impact development (LID) helps reduce the volume of stormwater that flows into drains during a rainstorm. Green infrastructure uses plant or soil systems, permeable surfaces, stormwater harvesting and re-use systems, and landscaping to store, filter, and reduce the flow of stormwater.
In 2017, Marysville, along with the Washington State Department of Ecology (Ecology)’s Water Quality Combined Funding Program, funded the design and construction of improvements for First Street and Third Street, which are two of the city’s main downtown corridors. In 2018, the city and Ecology partnered on additional green infrastructure projects, which will be located on both Second Street and Cedar Avenue. The design phase for these projects has already started. Construction for the Cedar Avenue projects will begin in summer 2021. Construction on Second Street will follow in spring or summer of 2022 and continue through June 2023.
Marysville is also in the planning phase of building a regional stormwater treatment facility, with grants from Ecology’s Water Quality Combined Funding Program. The facility will be located on the former Geddes Marina site, close to the city’s waterfront, and it will be incorporated into the site of a future city park. When completed, the facility will treat runoff from more than 460 acres of pollution-generating surface.
Brooke Ensor, National Pollutant Discharge Elimination System coordinator with the City of Marysville, thinks that addressing stormwater runoff has become a priority for the city because momentum has been building for these types of projects over the last few years, and they improve the quality of life for residents. “We’re always looking for opportunities for dual uses,” she said. “The downtown has been a very big planning focus for the city. And so the idea of greening it and adding more walkability and stormwater features at the same time is appealing.”
First Street and Third Street
Marysville’s First and Third Streets are in the downtown area that sits close to Ebey Slough. Both Benton and Ensor mentioned that the city has been working on improvements to the downtown area, and that the recent green infrastructure projects have yielded impressive results and produced multiple benefits for residents.
For both First Street and Third Street, the city installed bulb-outs, or curb extensions. On Third Street, the bulb-outs contain bioretention cells, or rain gardens, to filter stormwater runoff. First Street has bioretention cells installed in sections parallel to the road. The bioretention cells are filled with a treatment media — compost soil — in the bottom, and vegetation that includes native plants. These improvements slow down the flow of stormwater runoff and filter pollutants from the water as well. “The city as a whole decided that’s how we want to handle stormwater down here in the downtown core — take it offline, put it back in the ground, and not have it go out to Ebey Slough,” Benton said.
Besides the green infrastructure improvements, the city’s use of bulb-outs, high visibility pedestrian crossings, roundabouts, and medians has slowed traffic and improved the walkability along First and Third.
But even beyond these projects’ primary benefits — of treating stormwater runoff and improving safety for drivers and pedestrians — there have been other benefits for Marysville residents, and particularly those who live on Third Street.
“There was some apprehension in the lead-up to the project,” Benton said. “We did a lot of public outreach and it was fun to watch everybody come around to this project as they saw it being built and then lived with it, because they realized the benefits of the beautification. They realized the benefits of the surface water improvements for the Sound and Ebey Slough.”
Both Benton and Ensor mentioned that residents, particularly on Third Street, have been grateful for the improvements, and the city has heard a lot of positive feedback. Benton explained that some of the long-time Third Street residents were so inspired by the bioretention cells and other infrastructure that they decided to spruce up their own houses, improve their landscaping, and plant annuals on the medians along the street.
Amy Waterman, a municipal stormwater grant specialist with Ecology, has worked with the city on these projects. She emphasized that the improvements in Marysville have had numerous effects beyond their initial implementation. “There’s a lot of discussion about the secondary benefits of green infrastructure,” she said. “And I think this is an interesting example that you don’t often hear about — it’s beyond the actual plantings or the low-impact development itself. It’s what happens to the existing neighborhood.”
Plans for Second Street and Cedar Avenue
This summer, Ecology announced that it awarded more than $226 million in grants and loans to improve water quality for communities across the state and support more than 2,500 jobs.
The City of Marysville was awarded a grant to do more green infrastructure projects on Second Street and Cedar Avenue, as a follow-up to the projects that happened on First and Third. The projects will treat stormwater runoff that enters Ebey Slough, in addition to providing a number of other benefits to the downtown corridor in Marysville. Both Second Street and Cedar Avenue have a mix of commercial and residential properties, like First and Third streets.
“We’re going to see the same types of treatments on Second and Cedar, just because of the nature of the roadways,” Benton said. “Second will look just like Third. Cedar will be a bit of a mix between First and Third where we’ll have some of those more linear bioretention vertical-walled cells. And then we’ll also have the bulb-outs.”
Marysville’s stormwater treatment facility
When asked about what Marysville has been doing with green infrastructure and stormwater runoff treatment, Ensor doesn’t hesitate to show her enthusiasm for the city’s initiative. “We’re proactively doing all these retrofits, because waiting for redevelopment to fix problems of the past is not going to be a quick solution,” she said. “We’re not going to get to our recovery goals if we wait for redevelopment. So I think it’s great that the city has taken such a proactive approach to doing some of these big projects.”
One of the city’s biggest projects is the construction of a stormwater treatment facility that will be located close to the waterfront. As part of the city’s plans to revitalize the downtown area, it purchased the Geddes Marina site in 2010 and the neighboring Welco Mill site in 2016, both of which are on First Street and near Ebey Slough. Marysville purchased the Geddes Marina property with plans to make stormwater improvements and add park facilities. With the help of grants from the EPA, the city is engaged in ongoing remediation at both sites due to their historic industrial uses. Remediation and capping work is due to be completed in 2022.
Inspired by the City of Tacoma’s Point Defiance Regional Stormwater Treatment Facility, Marysville partnered with Ecology to formulate the best design for the new stormwater treatment facility. The city and Ecology arrived at a design that reduced the potential size of the facility and increased the amount of runoff from the basin that could be treated.
“Between these rain garden projects that we’re scattering throughout downtown and this large treatment facility, we’re going to be able to treat a lot of the stormwater from the downtown area that comes into that discharge location,” Ensor said.
The design and construction of the stormwater treatment facility has been split into two phases, with existing funding covering the design of both phases and the construction of the first phase. According to the city, the first phase facility will treat runoff from 231 acres of pollution-generating surface, and site preparation for the first phase has already started, with construction expected to finish in 2022. The second phase of the facility will treat runoff from another 231 acres of pollution-generating surface. Marysville has applied for fiscal year 2022 funding for the construction of the facility’s second phase.
The stormwater treatment facility will be entirely located at the Geddes Marina site and will be incorporated into a future park that the city’s designing. This means that instead of industrial concrete structures, the stormwater treatment facility will be realized as accessible park elements that will enhance the park’s landscape.
“Marysville is one of the few smaller jurisdictions that are doing these types of projects,” Ensor said. “It’s more common for bigger jurisdictions to have retrofit programs. And I think it is also a little unique that we’re putting in rain gardens. There’s not a lot of smaller jurisdictions that are electing to put in these types of facilities.”
Why is it important to treat polluted stormwater runoff?
Polluted stormwater runoff degrades water quality and damages habitat. The contaminants in polluted stormwater runoff harm salmon and other wildlife. As Ecology outlines, unmanaged stormwater runoff can also contaminate swimming areas, pollute shellfish beds, and contaminate groundwater.
Benton said that the downtown area of Marysville had old stormwater infrastructure, which meant that, before the green infrastructure improvements and retrofits, stormwater runoff was directly discharged into Ebey Slough and into the Sound.
“By taking these LID approaches that we all know work and using the infiltration and the bioretention soils and the vegetation, we’re removing that negative input, small basins at a time,” he said. “The more the city does this, and the more that we can achieve these projects, the less of a negative impact we’re having on the environment and the waterway.”
Waterman explained how beneficial it is that Marysville’s retrofit projects are capturing stormwater runoff, especially since retrofitting existing development is not required by Marysville’s Phase II permit at this time. “It’s very important to be able to capture stormwater runoff that’s not currently being treated,” she said. “These particular projects are treating for total suspended solids, oil, dissolved copper and zinc, and total phosphorus. And a lot of it comes from the infiltration — Marysville is very lucky to have this great soil that a lot of communities would die for. The native soil is providing a lot of that treatment, and by slowing it down, it gives the stormwater a chance to be filtered before it gets to the Slough.”
Like Benton, Waterman had an experience that shaped the way she thinks about stormwater runoff. Waterman did some volunteer work about 10 years ago with a National Oceanic and Atmospheric Administration (NOAA) project that was sampling coho salmon in Pipers Creek, in Seattle, and looking at pre-spawn mortality, a phenomenon where coho salmon die before spawning when they return to freshwater. “It was really sad,” she said. “Every single salmon that we found was dead and full of eggs, just one after the other. We also saw fish flopping around in the water, swimming oddly. It was a pretty stark image.
“Even at that time, researchers knew that road runoff was the culprit — the going theory at that time was that a component of brake dust might be causing the mortality,” she said. “And now, we have the results announced just last week in Science, “A ubiquitous tire rubber–derived chemical induces acute mortality in coho salmon,” from WSU, UW, NOAA, and others. The researchers have found a specific chemical compound in tires that causes pre-spawn salmon mortality. This was some very impressive scientific sleuthing built on previous research of Jenifer McIntyre that clearly demarcated the lethal impact of highway runoff and the clear benefit of filtering stormwater through soil. All this is more evidence of the importance of the green infrastructure approaches incorporated into Marysville and other communities’ stormwater management. Of course, it is too early to know if any BMP [best management practice] currently in use specifically prevents this tire compound from reaching waterways. That would be a great next research endeavor.”
“Our creeks, although they’re small, are definitely providing spawning and rearing habitat for salmonids,” Benton added. “And so, if we are polluting those waterways, which we all know that we are, then we are polluting those spawning and rearing habitats. So if we can do more of these LID projects where we’re infiltrating where we can, or we’re retaining that water for longer and treating it, then we’re improving the water quality in those habitats.”
Green infrastructure improvements are attainable for cities and towns throughout the state
Although doing retrofit projects and installing green infrastructure might seem like a tall order for a lot of cities and towns, Benton and Ensor both stressed that the city’s partnership with Ecology has made it easier to embark on these projects and less burdensome financially for Marysville.
Discussing the projects on First Street and Third Street, Benton said, “It was really nice to have the opportunity to have a project that was, in large part, funded by Ecology. That took some of that pain off the city and allowed us to realize that these projects are relatively easy to construct and they have all of these myriad benefits.”
Waterman explained that there’s a lot of opportunity for local governments to take advantage of the grants that Ecology offers. “I’d love communities to see that it’s very much worth it, and they can create some great projects and great partnerships. We look forward to seeing more projects like this.”
She mentioned that Ecology is also seeking out pilot projects that involve community public-private partnerships. Waterman said that these types of public-private projects sometimes include private capital as part of a funding package. With ecological restoration projects or green infrastructure improvements, the public-private projects often have goals related to environmental justice and job training for locals. “There’s a really interesting project in Prince George County [Maryland] called the Clean Water Partnership,” she said. “They have a dashboard where they document not only water quality goals but community goals as well. We’re encouraging folks to look at those potential public-private partnerships as another way to fund these retrofits.”