Representatives from Massachusetts Department of Transportation (MassDOT) gave a presentation Tuesday evening on the state’s proposed drainage and stormwater improvements to at-risk areas in Tisbury.
The project, which focuses on a small strip of road between Causeway Road and Beach Street Extension, and includes the municipal lot at 21 Beach St., aims to address the area’s chronic flooding and drainage issues.
Absent from the MassDOT plan were long-term solutions directly impacting the most problematic area affected — the Five Corners intersection.
Five Corners experiences frequent and severe flooding caused by extensive “impervious cover,” MassDOT project manager Hung Pham explained, in addition to it being the lowest-lying area within the watershed. Impervious cover — a surface that doesn’t allow for water absorption, such as roads and parkings lots — increases the rate and volume of runoff during storms, he said.
In what he called a “Band-Aid approach” to the drainage and flooding problem, Pham said the goal is to reroute stormwater runoff away from both Five Corners and Beach Street Extension, the current stormwater outfall location.
The plan proposed by MassDOT consists of installing additional catch basins along the project site, which would then be directed to underground infiltration chambers at 21 Beach St.
Up to 150,000 gallons of discharge could be stored there, Pham said, preventing flow to Five Corners. A catch basin at the intersection of State Road and Causeway Road would also be installed to reroute drainage towards the latter.
“No work is being proposed at the Beach Street Extension outfall at this time,” Pham said, adding that there is a potential to address both the extension outfall and Five Corners at a later date.
Following the presentation, Martha’s Vineyard Commission director Adam Turner said he was disappointed that the drainage plan excludes Beach Road Extension and Five Corners. Direct improvements “need to be done” to address those areas, he said, noting increasing severity and frequency of storms on the Island.
Five Corners, he said, “that’s a critical intersection … it’s important to the town of Tisbury, and it’s important to the Island.” Turner asked when that could be addressed; Pham could not offer a timeline.
“We know this will mitigate the problem,” Tisbury town administrator Jay Grande said, “but [it] doesn’t represent a total response to sea level rise and so forth.
“There’s much more work to be done,” Grande continued; “the Island has positioned itself to explore those strategies and make recommendations in the future.”
A handful of Islanders present at the forum also expressed concern about the plan.
“It seems to me that extending the Beach Road Extension outfall is the most direct and impactful solution to the flooding problem,” Geoffrey White said. “Why is that solution not being implemented?”
An extension of the outfall pipe at Beach Street Extension was considered, but deemed not feasible, Pham said, as it would need to be extended significantly further into the harbor to prevent clogging and maintain a positive flow. He said it could negatively impact Vineyard Haven Harbor and abutting properties. It would require extensive environmental permitting, and exceed any preferred timeline, he said.
Pham mentioned other alternative solutions to the problem that had been nixed, including a suggestion put forth by the EPA to direct water flow to Veterans Memorial Park. But that idea was quickly tossed; Pham said it would be impossible to direct stormwater runoff into the park “without significant impacts to the park.”
Overall, Pham said, “The project itself will be a drainage improvement project where we are improving the pipes up to Five Corners … [Beach Street Extension] is not being considered.”
Ben Robinson asked how much runoff would potentially be diverted from entering the Five Corners intersection through the Causeway and 21 Beach St. improvements, and whether it would “be enough to alleviate the flooding.”
Greenman-Pedersen Inc. project engineer Lindsey DiTonno, whose company is providing MassDOT with engineering and construction services, said that the storage chambers would fill as quickly as they infiltrate, best helping to mitigate inundation during smaller storms. In bigger storms, “it would be different,” she said.
The proposed system will be “as large as possible,” DiTonno said, “knowing that there’s not a large enough volume to solve this problem right now.”
MassDOT’s plan for Tisbury was developed through review of the 2018 Tisbury drainage master plan and studies by the Environmental Protection Agency and the University of New Hampshire in 2020.
By using data from those reports, Pham said, MassDOT was able to craft what they believe is a feasible plan. But the scope of the project is limited, Pham said, because of constraints of the existing drainage infrastructure and other challenges.
DOT just completed a big road and sidewalk project there and they’re just now thinking about dealing with the drainage? SMH
Has anyone suggested that this could be a losing battle: man vs nature? The flooding at Five Corners is a fairly recent occurrence and has been exacerbated by the recent work done in the area. We never saw anything remotely like this when I was younger.
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