MIDDLESEX - A little over two years ago, Woburn residents caught a glimpse of a phenomenon that hadn’t been recorded for generations: The return of Atlantic Ocean herring to Horn Pond.
Now, as area environmentalists track growing populations of native Blueback and Alewife Herring species returning to the area after being absent for a century, city leaders hope funding set aside to tackle climate change can improve the spawning habitat all while reducing large-scale flooding events around a residential neighborhood off of Lake Avenue.
Earlier this summer, during a virtual gathering via video-conferencing service Zoom, city officials joined with environmental activists and representatives from engineering firm Weston & Sampson to unveil a proposed restoration of a bottlenecked stream of the Horn Pond Brook.
The small tributary, fed by the Abjerona River, winds from the Aberjona River to Horn Pond by Scalley Dam, where a fish ladder opened two years ago allowed running herring to end their annual miles-long spawning run that crescendos in May and early June.
“This project has two components,” Corey explained during the public forum. “One is to alleviate flooding in the area and the other is to provide better fish migration to Horn Pond.”
“There’s been some major flooding there over the past decade or so,” Justin Gould, a project manger from Weston & Sampson, later elaborated. “[The city engineer] has sent us some pictures from 2010 of some crazy flooding. There’s a manmade jut in the stream that narrows the brook where it flows into the dam.”
The recent workshop, held to solicit feedback from area abutters, was called after the community studied three options for alleviating the flooding by improving the flow of water along the stream. The analysis was conducted after the city received $235,000 in Municipal Vulnerability Preparedness Grant (MVP) funding that is aimed at helping cities and towns combat the future challenges of climate change.
Under the preferred brook restoration scenario selected by the study team, the river bed would be restored by cutting back a bottleneck nearby the University Avenue apartment complex. Though the residential complex itself dates back to 1982, the land topography was altered decades earlier when a previous owner filled in a low-lying area by the brook.
The fill, added right near a natural bend in the waterway, apparently blocks excess brook flows from running into a natural wetlands area beside the river bed. The elevated terrain, now the site of nine parking spaces for tenants, is commonly left underwater following severe storms.
According to Gould, to fix that problem, the team would remove part of that fill and widen the green-space along the stream. Weston & Sampson also proposes building back up the opposite side of the brook, where flood-surged water flows have slowly eroded away from the bank over the past decade.
“That [edge of the parking area] is there from fill that was brought in decades ago, and with that built up area, everything bottlenecks at one of the sharpest bends [of the brook],” Gould said. “So by easing that bend and reducing that fill area, when you have a high-flow or flooding stream, the water can make it over to [the natural low-lying green-space].”
“There’s parking provided there and this bump out would be substantially reduced in size, if not eliminated entirely,” furthered the Weston & Sampson engineer, who believes four spaces could be recreated in a new parallel parking arrangement. “The reduction of the other five spaces is what we’re focusing on right now, so there’s no loss in parking.”
Though city officials looked at another alternative which would also presumably alleviate the flooding by shoring up the brook banks and removing downed trees and debris further downstream, that cheaper project option would do nothing to increase flood storage.
According to Weston & Sampson representative Amanda Cohen, an urban planner who focuses on climate resilience projects, based on her research of climate change forecasts, the community should certainly expect to need that extra excess flood capacity.
Specifically, climate scientists say that average temperatures around New England have been rising by roughly one-half of a degree Fahrenheit each decade. By the middle of this century, should those models prove accurate, state residents should be seeing hot summers with more than a five-fold increase in the number of days with 90 degree or higher temperatures. There will also be milder winters marked by a drop in the frequency of below-freezing weather.
Perhaps more importantly, those changes are expected to bring a greater incidence of drought conditions during the summer months and a spike in the number of severe rainfall or high impact storms where more than 2 inches of precipitation is dropped.
“We’re expecting an increase an extreme participation. And when we look at the data from the 1950’s and 1970s, we can see its increased. What we’ll really see is an increase in is the intensity of those storms,” she said.
Those looking at restoring the Horn Pond Brook area say the project is exactly the type of improvement envisioned under the state’s MVP program.
Established in 2017 by Mass. Governor Charles Baker, the MVP initiative is managed by the state’s Executive office of Environment of Energy and Environmental Affairs (EOEEA) as a way to help cities and towns take proactive steps towards managing the expected weather chaos.
In 2018, Woburn received a planning grant after defining a list of community vulnerabilities and proposing several local strategies for adapting to those challenges. Ultimately, protecting electrical infrastructure and flood management, particularly around the Four Corners area, sections of East Woburn, and the Horn Pond region, featured prominently in the city’s initial MVP assessment.
To date, funding from the MVP program has helped nearly 200 communities across Massachusetts with the development of similar climate change strategies. As of last spring, nearly $10 million was allocated to the handful of cities and towns that have applied for funding and obtained approval of MVP action plans.
Woburn has thus far qualified for $235,000 in grants to further plan some of its MVP plan initiatives. Now that the funding has been used for preliminary design of the brook restoration, the city now hopes to seek construction monies.
According to Corey and other city officials, though the flooding around the University Apartment complex is not the worst experienced in the city, the Horn Pond Brook restoration plays into the community’s larger strategy of managing stormwater by repairing stormwater culverts and restoring blocked flows to wetlands and river/streams.
For well over a decade, environmentalists have been focusing on adding fish ladders and other waterway improvements in order to facilitate the annual herring run from the Atlantic Ocean to Horn Pond and other area water bodies, such as the Mystic Lakes by Winchester, Medford, and Arlington.
For centuries, the two species of herring native to the area swam up the Mystic River from the Atlantic Ocean to spawn in the lake and ponds, which is situated as far as seven-miles away from their natural salt-water environment.
The herring, which when fully matured can grow to as long as 10-inches long, are considered essential to the survival of various other fish and bird species. However, for about a century, the herring were cut-off from Horn Pond and the Mystic Lakes in Winchester due to manmade dams and other obstacles.
Two years ago, Woburn residents were able to see herring return to the waters for the first time in 100 years after a fish ladder was added. Since that time, as many as 10,000 herring have been counted heading into the pond during the annual run.
According to the Mystic River Watershed Association, a non-profit dedicated to protecting regional waterways that include the Aberjona River, since 2012, activists have observed herring numbers in the tributaries increase from 199,000 to 630,000 in 2017.