Commission leaning into up-Island nitrogen remediation

The MVC is looking into the best ways to improve water quality throughout up-Island watersheds, including Chilmark Pond, seen here. —MV Times

The Martha’s Vineyard Commission is recommending a number of options for the up-Island towns to address nitrogen pollution in local waterways, including the installation of so-called innovative/alternative (I/A) septic systems.

Commission staff on Wednesday presented wastewater planning focused on Chilmark, in anticipation of pressure from the state government to implement remediation.

The presentation came Wednesday at a Chilmark board of health meeting.

Commission executive director Adam Turner said the state gave the commission funding two years ago to develop wastewater management plans for each up-Island town. Turner also said that he is interested in involving the Wampanoag Tribe of Gay Head in the process.

On Wednesday, Rachel Sorrentino of RJS Development Solutions presented background information and nitrogen-reduction goals for Chilmark’s four watersheds — Chilmark Pond, Tisbury Great Pond, Menemsha Pond, and Squibnocket Pond.

Sorrentino presented the board of health with estimates of nitrogen loads entering the town’s ponds, and the impacts possible solutions could have.

In order to meet the total maximum daily load (TMDL) of nitrogen provided by the state Department of Environmental Protection, the lower section of Chilmark Pond would require a 53 percent reduction from 2023 levels. For Menemsha Pond, Sorrentino said a 33 percent reduction is required; Chilmark is responsible for four-fifths of that pond’s nitrogen load, with the rest coming from neighboring communities.

For possible solutions to nitrogen loading, Sorrentino focused on reduction, remediation, and restoration. Each pond will require a different approach, largely depending on where the nitrogen comes from.

Solutions presented at the meeting were meant to serve as a menu for Chilmark to consider and choose from, before forming a plan and seeking funding opportunities.

Reduction, which involves addressing nutrients at their sources, includes managing or limiting development, and managing household and other waste. This could mean reviewing certain projects to maintain nitrogen load limits, as well as land preservation and growth control. At households, this could involve installing I/A septic systems and waste-reduction toilets. Nonagricultural fertilizer could also be a management target.

Remediation includes stormwater management, installing permeable reactive barriers (PRBs), and utilizing green infrastructure. For stormwater management, this could include vegetative swales, gravel wetland, and soil media filters that keep nutrients from getting into the groundwater. For green infrastructure, Sorrentino said, constructed wetlands could extract nitrogen from an environment. Afterward, plants can be removed and reused as fertilizer or compost.

Possible restoration solutions include shellfish and seaweed harvesting, as well as habitat alteration and restoration. That could involve dredging and channel widening, and coastal habitat restoration.

Sorrentino hopes that applying these “if/then” solutions — that is, determining which of the options best match each watershed — could occur by the end of January. 

“A lot of the heavy lifting for those has already been done,” Sorrentino said.

At the meeting, Turner responded to questions about the funding required to implement solutions. 

“I don’t want to act like somehow there isn’t going to be any cost to the communities,” Turner said. “But the communities could bond or do other things, and set up enterprise funds. There are a lot of different ways … We’ll get as much as we can, and again, those costs and those programs are going to be your decisions.”

Turner also stated that costs will vary depending on what solutions Chilmark chooses, and a plan will be required in order to attract state funding. “In a shallow pond, a dredge might be something that you need to do. Then that’s a different kind of a cost,” said Turner. He said there were also regional funds that could be available to Chilmark.

Though MassDEP has not mandated nitrogen remediation on the Vineyard, it did do so on the Cape, in July. Regulations for the Cape state that if pollution is not remediated, residents could be forced to install nitrogen-removing technology in their backyards.

Board member Matthew Poole agreed with the commission that now is the right time to focus on wastewater management. “Right now, we’re not under an order from the state,” said Poole. “It’s coming. I think we need to get ahead of it, but right now, our clock is not officially ticking.”

The board of health tentatively set a follow-up discussion for its Feb. 7 meeting.



    problem solved
    as if any affluent privileged people would actually deal with their crap.
    But good news– your Immigrant house cleaners would
    be more than happy to take the tray out of your composting
    toilet every 4 months and put it on your flower beds.
    And your gardener will be very happy about it also.

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