Herring River Watershed Report ID’s Solution To Nitrogen Issue

BREWSTER – A report presented to the select board Monday found a unique, cost-effective way to mitigate nitrogen in the town’s nitrogen sensitive Herring River Watershed and fulfill state requirements: buy a conservation restriction on land in neighboring Harwich. 

 In 2023, Massachusetts released a new set of regulations for nitrogen-sensitive watersheds. In an effort to reduce the amount of nitrogen seeping into these watersheds, the state set an aggressive five-year timeline to get permits in place. Because the town began work on the permitting process to comply, the requirement that residents update Title 5 septic systems to expensive nitrogen-reducing systems was suspended. 

 Last year, the town applied for state grant funds to focus on its water resource planning, specifically concerning the Herring River watershed. This year, the town applied for the same funding, around $130,000, to assist in developing the watershed permit. In addition, the funding would help to look at the feasibility of wastewater management on the Sea Camps Pond Property if a proposed housing development is approved. Officials would also generate wastewater solutions for the pond property. 

 The Herring River watershed makes up a large portion of the southern area in Brewster, including Long Pond, Sheep Pond and Seymour Pond. 

 The ponds help to reduce the amount of nitrogen in the watershed due to attenuation, which helps filter out the nutrient. Some 90 percent of the nitrogen that goes to Sheep Pond is attenuated, 69 percent of the nitrogen that goes to Seymour Pond and 73 percent of the nitrogen that goes to Long Pond is absorbed. 

 Based on the new regulations, the town only has to manage the nitrogen loads from development after 2004. Between 2004 and 2024, 60 available parcels saw construction of 86 homes which have produced 105 kilograms of nitrogen a year.

 A remaining 35 buildable lots, including the Sea Camps Pond Property, could see an addition of 73 homes, which would equal another 40 kilograms of nitrogen a year.

Given these figures, Brewster must account for 145 kilograms of nitrogen a year to receive the Herring River watershed permit. In comparison, Harwich is responsible for 5,400 kilograms of nitrogen a year for the Herring River. 

 Currently, the town is already contributing to nitrogen mitigation tactics including innovative or alternative septic systems, adhering to a fertilizer bylaw, limiting fertilization of Warners Bog due to restoration efforts and public water connections. These practices are removing 87 kilograms of nitrogen a year, which will be added to the permit application. 

 Mark Nelson of the Horsley Witten Group, a consultant the town has worked with on the permit, suggested a unique way to cover the remaining requirements of nitrogen mitigation. 

 Nelson proposed purchasing a deed restriction prohibiting further fertilizer application of Thacher’s Bog in Harwich. The Harwich Conservation Trust (HCT) recently purchased the bog. In conversations with the HCT, Nelson said there was an opportunity to purchase the deed restriction covering 16 acres of the bog that would meet the full requirements, removing 150 kilograms of nitrogen from the Herring River.

 Based on a state figure of around $15,000 per acre, Nelson suggested the full price would be $241,000. The purchase would require a town meeting vote, which could come as soon as November.

 While this is the preferred solution, the permit application requires backup options. The report specified two such strategies, including connecting a 20-home neighborhood to a treatment system or creating a wastewater treatment plant for a 44-home neighborhood. The cost of these projects ranged from about $1.4 million to $4.8 million and included yearly maintenance of up to $100,000. 

 If the deed restriction is purchased and the permit application is approved, the town will only have to provide five-year updates on the permit status to the department of environmental protection. 

 Town Manager Peter Lombardi said the town has developed a water stabilization fund which receives around 15 percent of the estimated short-term rental revenues each year. The current balance of the fund sits at $250,000, enough to cover the cost of the deed restriction. 

 “Once we satisfy the requirement of our state-level permits for the Herring River Watershed, it does not mean our work is done in terms of water quality and wastewater management,” said select board member Amanda Bebrin. “But my understanding is that it does mean we have more control over which strategies we use and where we might like to put them. The state is dictating the checklist of things we need to complete, and once those are completed, we can do more of a bottom-up community, town-generated [decision on] where we think things should be located and what strategies we pursue.” 

 Because the Herring River is largely located in Harwich, Nelson said completing those obligations for the watershed will open Brewster up to focus more on the town’s own integrated water resource management plan.