The East Hampton Town Trustees were agreeable to the proposed rebuilding of a bulkhead on Three Mile Harbor when they met on Monday.
They were also amenable to a proposed installation, behind that bulkhead, of a permeable reactive barrier — typically a long, narrow trench filled with a material such as iron, limestone, carbon, or mulch to remove contaminants as groundwater passes through it — that would prevent an estimated 500 pounds of nitrogen from entering the water body annually.
Peter Mendelman, who with his family owns several marinas on Three Mile Harbor, seeks an emergency bulkhead replacement at 60 Harbor View Lane, a residential parcel adjacent to Harbor Marina, one of his family’s businesses.
The bulkhead, John Aldred of the trustees said, is effectively attached to that of the Harbor Marina. The existing bulkhead at 60 Harbor View Lane is old and failing, he said, and Mr. Mendelman would like to rebuild it one foot taller to reach the height of the Harbor Marina’s bulkhead.
Mr. Mendelman was not at the meeting, but Ron Paulsen, a hydrogeologist and groundwater specialist with Cornell Cooperative Extension of Suffolk County’s Marine Program, has discussed the installation of a permeable reactive barrier behind the rebuilt bulkhead with the applicant and with officials in the town’s Natural Resources Department.
Mr. Paulsen has been conducting surveys of embayments in the town for the past five years, he told the trustees. As part of that effort, he has surveyed different areas in Three Mile Harbor. The area by the Harbor Marina “was very high in nitrogen coming through” via groundwater discharge, he said. Follow-up survey work in the spring confirmed “really high groundwater discharge rates” and “a lot of nitrogen” at the failing bulkhead. A colleague, he said, estimated 500 pounds of nitrogen per year coming through the bulkhead by way of groundwater.
It “really became obvious” that behind the bulkhead was an ideal location for a permeable reactive barrier, Mr. Paulsen said. Kim Shaw and Mellissa Winslow in the Natural Resources Department are supportive of the proposal, he told the trustees.
Replacing the bulkhead, which would require the trustees’ approval, would be the property owner’s financial responsibility, he said, but funding for the installation of the barrier could come from the 20 percent of community preservation fund proceeds that can be used for water quality initiatives annually, as approved by voters in a 2016 referendum.
The next round of grant applications for water quality improvement projects are due on Aug. 1, after which the town’s water quality technical advisory committee will consider the merits of each application and issue recommendations to the town board, which votes on approval of the expenditures.
Mr. Mendelman “wants to get going this fall, as soon as possible,” said Mr. Aldred, who serves on the technical advisory committee and indicated that he would recuse himself from the trustees’ vote on the bulkhead replacement. “We can put this up for a vote at the next meeting,” on July 24, he said.