No Blockbuster Wastewater Projects For Brewster

BREWSTER – Thanks partly to lucky topography and partly to careful planning by the town, Brewster taxpayers don’t need to brace for any blockbuster wastewater treatment projects like those underway in Chatham, Orleans and Harwich. That was the news the select board and health board heard from a town water resources consultant this week.

 Mark Nelson of Horsley Witten Group provided the update on the implementation of the town’s integrated water resource management plan Monday, focusing on the watershed permits the town must obtain to avoid requiring large numbers of residents to upgrade their septic systems. Updates to the state’s Title 5 regulations in 2022 stipulated that all septic systems in the region must be upgraded to treat nitrogen within five years, unless the town obtains a watershed permit exemption or files plans to do so. 

In Brewster, groundwater in the northern half of town flows toward the bay, where vigorous tidal flushing washes away nutrients from septic systems before they can harm ponds and estuaries. The southern half of town sees groundwater flowing toward four water bodies: Pleasant Bay, the Herring River in Harwich, and Bass River and Swan Pond River in Dennis.

 To meet nitrogen management goals in each area, the town must not only control the nutrients present when the permit was first obtained, but also that from new and possible development. The goal is to remove 75 percent of the overall nitrogen load in the first 20 years of the permit.

 The Pleasant Bay watershed, which includes Brewster neighborhoods around Freeman’s Way and Route 39, contributes about 13 percent of the nitrogen entering the bay. Brewster is a member of the Pleasant Bay Alliance, which secured a watershed permit years ago and is in the process of revising it. Much of the watershed in Brewster is open space, thanks to Nickerson State Park and large tracts of land preserved to protect the town’s drinking water wells, and that undeveloped area is part of the reason the watershed only contributes 13 percent of the nitrogen load, though a quarter of the Pleasant Bay watershed is in Brewster. In this part of town, controlling fertilizer use at Captains Golf Course has been key.

 “The primary driver why we’re not looking at some of these much costlier wastewater solutions in the Pleasant Bay watershed is because of the great work they've done to modify their practices,” Town Manager Peter Lombardi said. Grounds crews stopped fertilizing certain areas of the rough and replaced annual granular fertilizer applications with targeted applications using a GPS-guided sprayer that only applies fertilizer when, and exactly where, it is needed. 

“And it hasn’t really negatively impacted the course,” he said. Nearby Cape Cod National Golf Course has also reduced its fertilizer use. In all, the town is already removing 74.5 percent of the nitrogen load, and expects to reach 97 percent with additional measures.

 One of those additional measures involves challenging the assumptions about how much fertilizer applied to the golf course actually leaches into the groundwater. “A couple years ago, we went to town meeting and got approval for funding to install the measuring devices to look at the leaching rate assumptions,” Lombardi said. The equipment is showing that the nitrogen impact on the watershed is actually less than anticipated, and town officials hope the difference will be credited toward Brewster’s reduction target.

 On the other side of town, a small sliver of Brewster off Slough Road contributes to the Swan Pond and Bass River watersheds in Dennis and Yarmouth. The town task force working on water quality recognized early on that Brewster’s contribution to the pollution here was a tiny fraction of that coming from Dennis and Yarmouth, and lobbied successfully for a provision in the new Title 5 regs exempting the permit requirement for such minimal amounts. 

“It’s a handful of residents in the southwest corner of town, but they have certainty now” that they won’t need to install expensive nitrogen-removing septic systems, Lombardi said. 

 Some creativity might be needed to meet nitrogen removal targets in the final watershed, the Herring River system that covers the area north of Long Pond and between Hinckley’s Pond and the Harwich line. In this area, the town is responsible only for removing nitrogen from new development after 2004, and Long Pond, Sheep Pond and the other surface water bodies here remove much of the nitrogen through natural processes, Nelson said. Still, the town will need to remove nitrogen associated with the 35 remaining buildable lots in the area, which could accommodate 73 homes. The number includes the planned housing development at the Sea Camps Pond Property. 

  A number of strategies are possible to meet that target, including the restoration of the Warens cranberry bog at Hinckley’s Pond, where fertilizer is no longer being applied. A credit for this restoration would reduce almost a third of the watershed’s nitrogen load. Meeting the target likely means some upgrades to residential septic systems. 

 “It would be between 40 and 45 homes, you’d have to treat to 10 milligrams per liter,” but if the bog restoration is credited, the number might be as small as 32 homes, Nelson said. That could be accomplished by individual septic system upgrades, or by installing a cluster septic system for a neighborhood like the one planned for the Sea Camps property. A neighborhood sewer system here might also be used to connect existing neighbors in the area, causing a potential reduction in nitrogen pollution over existing conditions, he said.

 “The other option is, could there be a deal struck with the town of Harwich?” Nelson said. A nitrogen “trade” could provide a better outcome for the Herring River at less expense to Brewster taxpayers, he noted. “That discussion is something that hasn’t begun yet, but should stay on the table,” he said. When it comes to finding ways to meet the nitrogen targets in the Herring River watershed, “further public discussion on this is going to be important,” he said.

 The town’s integrated water resource management plan takes a broader look at water quality in town, and will include updates on northside estuaries, freshwater ponds, drinking water and stormwater. The current 2013 version of the plan is now being updated using funds authorized in this year’s annual town meeting.