In this Oct. 29, 2019, file photo, University of New Hampshire scientists monitor the health of seagrass in the Great Bay in Durham, N.H. Federal officials have finalized a plan in November 2020 to reduce pollution in one of the largest estuaries in the Northeast. Credit: Michael Casey / AP

Federal officials finalized a plan Tuesday to reduce pollution in one of the largest estuaries in the Northeast with an approach that gives surrounding communities greater flexibility to address the problem.

The Environmental Protection Agency, in the Clean Water Permit for the Great Bay in New Hampshire, calls for a dozen communities that ring the bay to reduce the amounts of nitrogen going into the waters. It allows them to reduce nitrogen by treating sources like storm water runoff and septic tanks, rather than making costly upgrades to their wastewater treatment plants.

“This permit is an important and innovative approach for a significantly cleaner, healthier Great Bay and reflects many years of hard work among federal, state and local governments to address a critical environmental problem,” EPA New England Regional Administrator Dennis Deziel said in a statement. “The permit is part of a federal and state approach that will reduce nitrogen in Great Bay in a cost-effective way, allowing municipal leaders the flexibility to make local decisions that are good for the environment and work for their communities. This is good news for New Hampshire communities and their ratepayer customers.”

The communities said they support a goal of improving the health of the bay, which has seen an increase in algae blooms and decline in eelgrass beds by 80 percent since the 1990s. Eelgrass beds are important because they have been found to provide food and shelter for fish, shellfish and sea turtles. Eelgrass also reduces coastal erosion and keeps the water clean by filtering out excessive nutrients.

Seven rivers carry pollution from 52 communities in New Hampshire and Maine into the 1,020-square-mile watershed for the bay.

New Hampshire Gov. Chris Sununu, a Republican, praised the EPA’s approach as allowing communities to manage their cost while being good stewards of the environment.

“This permit is a product of years of careful and deliberative collaboration between the communities it affects, the Environmental Protection Agency, and the New Hampshire Department of Environmental Services,” Sununu said in a statement. “Since this problem was identified over a decade ago, community stakeholders have worked hand-in-hand to develop this solution, which serves to benefit the environment, the economy, and New Hampshire’s communities.”

Some critics have questioned this approach, saying it allows communities to avoid costly upgrades to their water treatment plants and won’t reduce nitrogen levels low enough for the bay to fully recover.

Communities along the bay have spent more than $200 million reducing nitrogen from their wastewater treatment plants. Those moves have cut nitrogen releases by 70 percent, but the EPA says more needs to be done.

During a public hearing earlier this year, some municipal officials complained they have done enough and the additional requirements in this permit would be impractical and costly. They also warned that the reductions would limit their potential to grow, unfairly impact private property owners and were based on questionable science.

Communities have until April to decide if they want to opt-in to the permit. If they don’t, then the EPA would work with them to address nitrogen limits in their individual clean water permits when they come up for renewal.

A similar approach was taken in Connecticut, where a state permit calls for dozens of communities to reduce nitrogen from their wastewater treatment plans into the Long Island Sound.

Story by Michael Casey.