DOVER — Nitrogen levels in the Great Bay Estuary have risen to a point that puts vital plant life at risk, and state officials and environmental experts say action needs to be taken.
The primary solution under consideration, however, is expensive — many towns are facing wastewater plant upgrades that could cost up to $100 million, a bill municipal officials say local taxpayers can't afford.
Nitrogen levels in Great Bay need to be cut by half, according to numbers provided by the New Hampshire Department of Environmental Services for the Piscataqua Region Estuaries Partnership 2009 State of the Estuaries report.
Nitrogen has been shown to affect the growth of eelgrass, a significant contributor to Great Bay's ecosystem, said Fred Short, a research professor at the University of New Hampshire's Department of Natural Resources and the Environment.
Beginning at the mouth of the Piscataqua River, the Great Bay Estuary is one of the largest estuaries on the Atlantic Coast, according to the Great Bay National Estuarine Research Reserve website. An estuary is a closed body of water with rivers and streams flowing into it, and Great Bay's waters mix with Atlantic Ocean waters through its various rivers. The Estuary consists of several habitats that include eelgrass, mud flats and salt marshes.
The Partnership's research shows wastewater treatment plants contribute 31 percent of the nitrogen in the bay, with 65 percent coming from "non-point sources" like runoff or exhaust fumes in the atmosphere. But federal Environmental Protection Agency and state DES officials, as well as local experts, say the focus is on new rules for treatment plants because the technology exists to improve their output and upgrades could produce a more immediate nitrogen reduction.
The new regulations could affect wastewater treatment plants in 21 communities along the estuary, which include Dover, Durham, Exeter, Newfields, Rochester, Newington, Portsmouth, Farmington, Epping and Somersworth. Maine's Berwick, Eliot and Kittery plants could also be facing upgrades.
The new rules would be based on numbers establishing nutrient criteria for a body of water, which is based on many factors, including oxygen levels and turbidity — or cloudiness — in the water that can prevent sunlight penetration, and therefore plant growth.
Once the nutrient criteria is established, the level of nutrients released at each treatment plant is determined, which in turn sets the criteria for upgrades the treatment plants must do to achieve the appropriate reduction.
"Then it becomes the EPA's issue to start doling out permits," said Ted Diers, program manager for the DES Coastal Program, adding that the reduction refers to the amount of effluent released from each plant.
But achieving lower effluent levels can mean expensive upgrades to treatment plants. DES-proposed regulations would bring effluent levels down to 8, 5 or 3 milligrams per liter. The lower the number, the more costly the upgrade, said Dover City Manager Mike Joyal, adding that Dover would be looking at a cost of $20 million and Portsmouth $100 million to reach a 3 milligrams per liter amount.
"We're looking at a lot of money," said Rochester Director of Public Works Melody Esterberg. "What (the upgrade) does for Rochester is that we would have to do another upgrade to the wastewater plant on the same scale, from a monetary perspective, as what we did 10 years ago. And on top of that, the operation and maintenance cost would go up $1 (million) or $2 million a year depending on final limit of nitrogen. That's almost double what ratepayers are paying. People can't afford that."
It is these costs that have communities wondering if such upgrades are really necessary.
The Great Bay Water Quality Coalition, formed by residents, municipal officials and others, is focusing on sources of nitrogen other than wastewater treatment plants, arguing that upgrades may not solve the problem.
The upgrades "would require us to remove significant amounts of nitrogen from the effluent," said Joyal. "The science we've been reviewing suggests that the (nitrogen) levels may not be what's causing" increased turbidity.
The science at the core of the debate shows, among other issues, that eelgrass populations are declining due to nitrogen levels, but Joyal said some areas with high turbidity have healthy eelgrass populations.
UNH Research Professor Fred Short has been studying eelgrass at the Jackson Estuarine Laboratory in Durham for many years.
He has flown over Great Bay annually to monitor its prevalence and thickness in the water since 1984. He said the lab began to see an eelgrass decline in 2004, and in 2006, eelgrass was completely gone from Little Bay and the Piscataqua River. In Great Bay, Short said, eelgrass is also in decline. The reason, he said, is increasing turbidity in the water that blocks the light.
There are areas of turbidity in Great Bay where the eelgrass is not affected, he said, because it's "intertidal" and exposed at low tide.
"It gets a lot of sun and doesn't need clear water to survive," he said.
Turbidity can be caused by suspended sediments such as sand and runoff matter, or by an overgrowth of other plants like plankton and certain seaweeds that, Short said, feed on nitrogen.
"Both factors are an issue in parts of the Bay," he said.
Eelgrass decline is devastating, he said, as snails and fish lay eggs in it and it is food for ducks, geese and swans. It also buffers acidification from rain to help organisms thrive.
"Habitat value is its best known quality," he said.
Joyal said storm runoff from land and storm drains picks up nutrients on the ground and washes them out to Great Bay and the ocean. Fertilizers and other agricultural applications also are "by all indications" impeding the quality of Great Bay, Joyal said.
It is this information that has communities asking for another look at the science behind possible new regulations.
"It would be nice to have an independent study look at it," said Jamie Wood, director of the Somersworth Wastewater Treatment Plant, which went through an upgrade in 2005. "Someone neutral to look at it and ensure everything's right and go from there."
For Short, the science is clear: Increasing nitrogen is affecting eelgrass, and improvements need to be made as soon as possible.
"The technology is there to improve wastewater treatment plants," Short said. "And that's why they're feeling a lot of pressure. We don't know how to reduce non-point sources. We have to work together to reduce runoff. It's so bad now because we let it go for so many years."
Diers at the DES said that while "eelgrass certainly magnified the issue," the DES has been working on nutrient criteria for a number of years.
Diers said, "I would respectfully disagree with some of the statements that have been made that we don't have exact science on what is going on. We do."
He added that among these other issues, all the tributaries and rivers that flow into Great Bay have a dissolved oxygen problem. Ultimately, Diers said, the federal Clean Water Act, which governs water pollution, "sets up the process" for achieving improved water quality.
"It doesn't matter what I think or what the DES thinks," he said. "If the water is impaired, that means it has too much of something in it. The law says people have to reduce in order to meet that standard. Almost all of those wastewater treatment plants are up for permit renewal anyways. They know there's going to be nutrient removal, the question is how low is it going to be."
Short stressed that while improvements to treatment plants will help, it won't solve the problems in Great Bay and surrounding waters, and as a whole, people need to find realistic ways to reduce contamination.
"We have to develop better methods," he said, noting that people can't simply be told to stop using fertilizer.
Portsmouth already has upgrades on the horizon for the Pease Tradeport and Pierce Island treatment plants, which City Engineer Peter Rice said would bring nitrogen effluent down to 8 milligrams per liter at Pease if their consent decree is accepted. Piece Island's plant now releases 13 milligrams per liter.
But Rice maintains better science needs to be done to prove upgrades will make an impact.
"Nitrogen is the wrong thing to go after," he said. "It's only going to impact a small portion of the turbidity. By going after treatment plants ... it's easy, but we don't believe you're going to see a cost-effective solution because of that."
Diers contends they are not "picking on" wastewater treatment plants, but that change has to happen and will be a multi-decade process. Currently, the Southeast Watershed Alliance, a regional organization formed in 2009, is working to improve the state's coastal water conditions. Portsmouth is also undergoing $15 million in sewer work, investing in storm-water treatment and improve the stormwater drainage system, according to Rice.
Dover's Joyal said, "We would prefer there be a coordinated, holistic approach to solving this problem. We think there's an opportunity to generate some more reliable science to justify whatever solution will be imposed. We believe there's a willingness within the communities involved to do the right thing."
John Huff/Staff photographer
Graduate student Jonathan Felch, left, and his lab assistant Dylan Randazzo work on an environmental experiment involving life found in Great Bay at the Jackson Estuarine Laboratory in Durham.
Click here to view Foster's prints for sale
|
