Brewster buying conservation Restriction In Thacher Bogs

HARWICH – The Harwich Conservation Trust is working with the town of Brewster to reduce nitrogen input in the Herring River Watershed. Brewster is willing to purchase a deed restriction in Thacher’s bogs, owned by the trust, prohibiting the use of nitrogen.

Harwich Conservation Trust Executive Director Michael Lach and Mark Nelson, a principal hydrogeologist with Horsley Witten Group, made a presentation to the select board Monday defining Brewster’s plans to meet its nitrogen reduction obligations in the Herring River Watershed as it prepares to file the town’s watershed permit with the Massachusetts Department of Environmental Protection.

The Brewster Watershed Management plan calls for the reduction of 145 kilograms of nitrogen from the Herring River watershed, Nelson said.  

The Massachusetts Estuaries Project in 2013 established nitrogen reduction assessments, he said. At that time Brewster’s nitrogen load met the threshold goals for its portion of the watershed, and no nitrogen mitigation was required.

  However, Nelson said, the nitrogen loads from development from 2004 to 2024 and for future buildout must be offset to keep the town’s nitrogen load at or below the required threshold. Overall, this means that Brewster must reduce nitrogen loads in the Herring River Watershed by 145 kilograms a year.

Brewster has no connection to the Herring River, but its development has an impact on the watershed. The ground water moves north to south, noted Select Board Chair Donald Howell.

“Your water becomes our water,” he said.

Brewster is proposing to purchase a 16-acre conservation restriction in the 50-acre Thacher bog complex, which was recently purchased by the trust, with a deeded fertilizer use prohibition. The restriction is expected to result in a 150 kg annual reduction in nitrogen, thus exceeding Brewster’s management goal for the watershed.

Brewster would pay the trust $241,000 for the fertilizer restriction. The price was established on a per acre value of $15,000 established by the commonwealth for such activities, Nelson said. The funds would be used by the trust for eco-restoration planned for the bogs. 

Lach said the HCT board is scheduled to approve the agreement at its next meeting