The conservation commission has approved the eco-restoration of the Robert F. Smith Cold Brook Preserve along Bank Street. WILLIAM F. GALVIN PHOTO

HARWICH — The conservation commission last week approved the eco-restoration project planned for the Robert F. Smith Cold Brook Preserve. The project proposes major alterations to approximately 49 acres of fallow cranberry bogs through which Cold Brook passes off Bank Street, with the goal of reducing nitrogen levels in Saquatucket Harbor.

Commission members raised questions about how nitrogen attenuation will work under the proposal, which calls for developing small ponds and wetlands designed to remove nitrogen from groundwater before it reaches the harbor.

Commission members were also concerned about the protection of wildlife and plants during the major earth moving and water flow alterations in the construction process.

The preserve is owned by the Harwich Conservation Trust, and the non-profit is working with the town to restore the former wetlands. HCT Executive Director Michael Lach said the project has three major components: to enhance wildlife habitat, to improve water quality, and to allow visitors to experience the natural area. But he said the town's “primary interest is improving water quality by naturally reducing nitrogen, requiring less of a need for sewer infrastructure.”

Last Wednesday’s hearing was the second conducted on the notice of intent permit filed by the trust . Lach explained that there have since been three meetings to address issues raised in the first hearing. One was to address channel restoration and fish passage; another and onsite meeting held by the commission; and a meeting with commission member Brad Chase in his capacity as diadromous fisheries project leader with the state Division of Marine Fisheries about fish passage through the preserve to Grassy Pond.

As a result of the meetings, adjustments in design were made to improve stream flow for fish passage, said Nick Nelson, a senior geomorphologist with Inter-fluve of Cambridge, an aquatic engineering and ecosystem restoration firm retained for the project.

Commission member Mark Coleman sought assurances that nitrogen attenuation will work, and there will be a cost savings to the town through the reduction in sewering infrastructure.

“ I’m not necessarily opposed to it, but when I look at risk versus reward, I’m not really there,” Coleman said.

Eduard Eichner, principal of Tmdl Solutions, a consultant on the project, said the plan is to increase habitat through eco-restoration that will attenuate nitrogen. The town has a baseline on the nitrogen coming into the preserve now. Working with the state Division of Ecological Restoration, different strategies have been examined to increase nitrogen attenuation. There are different cells proposed in the restoration plan, including ponds that nitrogen-laden groundwater will seep into. Over time the conversion to saltwater marsh will increase the nitrogen removal, Eichner added.

“ We’re increasing habitat that will attenuate nitrogen,” assured Eichner. “The watershed flows from the north, almost up to Long Pond. It has the potential to treat a large portion of the (Saquatucket) watershed.”

  Chase said he understands the project will remove between 40 to 60 percent of the nitrogen in the groundwater before it reaches the harbor.

Nelson said the restoration will jump start recovery of what once was a salt marsh. Coleman wanted to know how much of a jump start is expected. The report said it would be in the 70-year range, he said.

Conservation Administrator Amy Usowski said the commission has not yet received the project approval letter from the state Natural Heritage and Endangered Species (NHES) Program.

Nelson said they have been working with NHES staff and there is a cell included in the project in which water willow is located and serves to support a moth population. No work will be conducted in that area. He also said they are tracking box turtles with radio tags to better understand their movement and working with Natural Heritage to develop a protection plan. He added that machine operators for the construction company will have to keep an eye out for the turtles and move them by hand. 

Conservation Commission Chairman Ernest Crabtree said an operator getting off a machine to move a turtle by hand “seems awfully casual.” He stressed the need to develop a plan that identifies the flora and fauna there now so there is information about “what we have today and what we’ll have there tomorrow.”

Nelson said seeds from all the plants will remain in the ground and will grow back rapidly. Usowski said the NHES program will oversee the protection of flora and fauna.

“ We don’t have a formal OK from Natural Heritage, and we will need it before a machine hits the ground out there,” said Usowski.

Coleman also expressed concerns about the absence of public participation in such a large project. He said many people he talks with about the proposal are not aware of it. Lach said there have been many news stories, meetings, and two lengthy pamphlets mailed out to the residents of the community keeping them informed. Coleman was reluctant to support the project, suggesting there are issues that need more clarifying.

“ It’s about the general ecological degradation of Cape Cod,” said commission member John Ketchum. “This is a well defined opportunity to address some of that, to counter some of the extensive development on Cape Cod. This is an opportunity to introduce a different independent approach [to sewering] to a means of nitrogen attenuation. I’m not sure what it will get us, but I think it’s very important to pursue that diversity.”

Usowski said that the charge before the commission is whether there will be any adverse impact on the wetlands from the eco-restoration project. The nitrogen attenuation issue is not part of the board’s deliberations, she said.

In the end, the commission voted 5-0 to approve the project. The conditions to be added to the will be clearly defined over the next two weeks and are expected to be approved in the Aug. 17 meeting.  

“ Harwich Conservation Trust looks forward to finalizing the Cold Brook eco-restoration project with the select board,” Lach said after the commission issued its approval.

Jesse Lewis Tuttle delivering coal to Stage Harbor Chatham, 1919. PHOTO COURTESY OF JOHN TUTTLE

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