Add bioswales up and down James Street. Convert a portion of Exchange Street into a linear trail park. And always keep parking lot dumpsters closed to avoid stormwater runoff contamination.
Those are among dozens of environmentally-conscious recommendations included in the new Mill River Watershed Plan, a 142-page comprehensive review of the current state of one of the city’s three rivers and an action plan for how to improve that river’s water quality and community accessibility.
On Tuesday afternoon, environmental activists and water pollution experts from the regional nonprofit Connecticut Fund for the Environment/Save the Sound unveiled the plan during a celebratory event held at the Eli Whitney Museum just across the Hamden-New Haven border in East Rock.
Around 40 local and state officials and concerned citizens showed up for the event, which was held just a few dozen feet away from Lake Whitney and the mouth of the Mill River stretch that runs through New Haven and down to the Long Island Sound.
“The biggest finding is that we want to capture as much stormwater coming off of paved surfaces as possible,” said Nicole Davis, Save the Sound’s Mill River Watershed coordinator. She said that Save the Sound’s next steps are to figure out how to implement some of the many recommendations included in the report.
Davis said that Save the Sound started drafting the report back in March with the support of a planning grant from the state Department of Energy and Environmental Protection (DEEP) through its federal Environmental Protection Agency (EPA) Clean Water Section 319 funding program.
Since March, she said, the regional nonprofit has held seven project steering committee and community meetings to identify current problems with and potential solutions for the river’s contaminated stretches.
The group also held a volunteer stream walk during which participants walked the entire stretch of the Mill River’s 38 square-mile watershed from Cheshire to the Long Island Sound.
Davis said that one of the primary goals of putting together the plan was to bring together interested stakeholders from the seven different towns through which the Mill River runs: Cheshire, Wallingford, Prospect, Bethany, Hamden, North Haven, and New Haven.
“The results weren’t surprising,” she said about the problems that they found with the Mill River.
Specifically, the river is contaminated with too much bacteria, primarily as a result of stormwater runoff, agriculture, combined sewer overflows, and other side effects from the past century of transportation, residential, and commercial development on the land around the river.
“Urban stormwater runoff is a significant source of pollutants and a leading cause of water quality impairments in the Mill River,” the final report reads. “Stormwater runoff from developed areas and other nonpoint sources of pollution in the watershed are major contributors of bacteria, sediment, and nutrients.”
Click here to read the full Mill River Watershed Plan.
Save the Sound President Curt Johnson, who grew up in Spring Glen and was East Rock Park’s first ever park ranger, said that the challenge now is to figure how to capture some of that stormwater runoff, get it back into the ground with gardens and other natural filters, and thereby reduce flooding and the level of bacteria getting into the river.
Which is where the watershed plan comes in. Thirty pages of the document are dedicated to recommended green infrastructure improvements that, Johnson said, would reduce the current bacteria load into the river by up to 40 percent.
Those recommendations include 10 specific projects that Save the Sound scoped out by location, recommended improvement, and estimated expense. Seven of those recommended projects are for sites in the Elm City.
At Elm City College Preparatory School at 407 James St., the report recommends planting a tree and installing a tree box filter just outside of the school’s parking lot and converting five feet of sidewalk adjacent to the street into a bioswale or rain garden with native grasses and other plantings that would help filter stormwater runoff into the ground and away from the sewer system.
“These bioretention areas could be integrated into the curriculum as demonstration sites to supplement lessons on science and the environment,” the report reads.
Estimated cost: $9,000 for the tree box filter, $20,000 for each bioswale.
The report also recommends that the school always keep its parking lot dumpsters closed to minimize trash’s exposure to stormwater.
The plan suggests converting James Street between Lombard Street and Chapel Street into a demonstration site for a “‘green streets’ approach to stormwater retrofit in the road right-of-way.”
That would mean adding one tree box filter and 13 bump-outs and curbside bioswales up and down James Street, for an estimated cost of $263,000.
“Bump-outs would replace a portion of the existing road shoulder with bioretention areas,” the report reads, “utilizing ‘No Standing’ zones near intersections to intercept stormwater runoff from the road. Bump-outs serve a dual purpose as traffic calming features, which can make residential streets more friendly to pedestrians and bicycles.”
And the report also recommends closing off a portion of Exchange Street near John S. Martinez School and converting four blocks of degraded roadway and vacant land into a linear trail park, building parklet next to the school’s playing fields, and expanding the Mill River Trail, several miles of riverfront walking and biking paths that will connect the Whitney Dam on Whitney Avenue to Criscuolo Park on James Street.
This project would remove 9,000 square feet of impervious surface from a portion of Exchange Street west of Haven Street and would help manage runoff from over 120,000 square feet of surrounding roadway and parking lots through 42,000 square feet of green infrastructure sites, thereby diverting over 3 million gallons of stormwater from the combined sewer system each year.
The Mill River Trail extension and Exchange Street conversion would cost around $300,000.
Davis said that Save the Sound has already submitted three grant applications to the state, the Great Urban Parks campaign, and a private foundation to raise money for some of the specific projects detailed in the watershed plan.
“Let’s all be a voice for getting people to experience the river,” Johnson said. “Not just to restore it, but to have trails, opportunities to go up and down the river and enjoy it.
“We can bring this back from the way it was when I was a kid,” he continued. “We can start halting a lot of that sediment and bacteria load.”
Davis said that next public meeting of the watershed plan steering committee will take place on Nov. 13 at 6 p.m. at the Eli Whitney museum.