Park’s Stormwater Innovation Centered On Reducing Polluted Runoff
July 2, 2020
Stormwater runoff pollution is a big problem for cities like Providence, where asphalt and pavement reign supreme. More than 30 percent of Providence is covered in impervious surfaces, according to a 2007 study, which means that stormwater runoff rarely gets the filtration it needs.
But in Roger Williams Park, the newly launched Providence Stormwater Innovation Center (SIC) hopes to change that.
The 435-acre park, in addition to housing a zoo, carousel, and tended green space, is now home to a project designed to reduce pollution from stormwater runoff and provide valuable insight into the methods and maintenance of these sites.
The installations, which include rain gardens, bioretention systems, infiltration basins, and sand filters, among other methods, were originally required as part of a consent agreement signed with the Rhode Island Department of Environmental Management (DEM) in 2017.
The water quality of the ponds in the city-owned park have long been a concern. Twenty-five percent of the total acreage of Roger Williams Park is ponds. Because of the park’s location within a highly urbanized setting, the ponds have become polluted with nitrogen and phosphorus. They are typically included on DEM’s list of impaired waters.
“Due to the elevated bacteria measurements…the Roger Williams Park Ponds do not meet Rhode Island’s bacteria water quality standards,” according to a DEM document on the health of the park’s watershed.
On a recent Monday, Brian Byrnes, deputy superintendent of parks and recreation for the city of Providence, and Ryan Kopp, Stormwater Innovation Center coordinator, gave a tour of some of the 42 eco-friendly stormwater filtration sites that were installed during the past two years.
“This one is called an infiltration basin, so the manhole cover over there used to be a catch basin that would take in stormwater off the street and it would flow directly into the pond through a pipe,” said Kopp, pointing to what looks like a shallow dirt well sparsely populated with a few small plants.
He went on to explain how it was modified so the stormwater runoff comes into the basin, slows down on a weir, and sediment drops out.
“We want to get rid of the contaminates and pollutants, but also the sediment, because it fills up the pond and makes it shallower and more susceptible to algae,” Kopp said.
Byrnes noted that maintenance crews can drive by, and from the seat of their truck, see if there is sediment present.
We walked onward, as Kopp and Byrne rattled off the different kinds of stormwater-mitigation techniques.
“Wet swale, dry swale, infiltration basin, bioretention, vegetated swale … ” said Kopp, counting on his fingers.
“There’s like eight or nine kinds,” said Byrnes, as we reached a lush overlook on the banks of Polo Lake. “But the work continues. We’re going to add a tree filter, which is a very common one, and we’re also going to do a tree trench.”
While installation of these physical projects is essential to stormwater treatment, Byrnes and Kopp noted that maintenance is a key piece of the puzzle that is often overlooked. It’s why the University of Rhode Island and the University of New Hampshire Stormwater Center were excited to be a part of the project.
“I think one of the things that attracted the UNH Stormwater Center was a missing a piece in the data, and that piece was the cost of construction and maintenance of these things,” Byrnes said. “How do you design them so they’re less expensive to construct and maintain? And when the people from UNH came down and saw this, they said this is the piece we’re missing.”
The SIC will also enlist volunteers through URI’s Watershed Watch program to help collect water data, and as part of their partnership with URI and the UNH Stormwater Center, the park’s closed Seal House is being converted into SIC’s unofficial headquarters.
“We want to take the Seal House and turn it into an information kiosk, and that’s where we will house some of URI and UNH’s water-quality monitoring equipment,” Kopp said. “We’re going to be able to measure real-time water quality and have it displayed.”
Byrnes, Kopp, and the project’s slew of other collaborators hope that over time others will look to Roger Williams Park as a model of what works, what doesn’t, and what it takes to commit to better stormwater management.
As we finished the recent tour, Byrnes pointed to a group of people cruising on swan boats on Willow Lake.
“That’s why we’re doing this,” he said.