Nitrogen and the Great Bay

The Great Bay estuary

Great Bay is a tidal estuary that straddles Rockingham and Strafford counties, stretching from the mouth of the Piscataqua River through Little Bay and into Great Bay at Furbur Strait, the drainage confluence of the Lamprey, Squamscott and Winnicut rivers. The Cochecho, Salmon Falls, Bellamy and Oyster rivers flow into the system between the Furber Strait and the open coast. Dover's Middle Road Wastewater Treatment plant discharges effluent into the Cochecho River. 

Often dubbed New Hampshire’s “hidden coast,” the Great Bay is unique because it is both a saltwater and freshwater system, or estuary, set apart from the coastline. The Piscataqua River brings salt water into the bay with the tides, an essential element for the growth of plant and animals that live in estuaries. Water levels in the bay are heavily influenced by these daily tides, which expose mudflats at low tide, providing important feeding grounds for birds. In recognition of Great Bay’s beauty, diversity and productivity, the U.S. Environmental Protection Agency has afforded special protection to it as one of only 28 “estuaries of national significance.”

Since the passage of the Clean Water Act in 1972, wastewater treatment plants, like Dover's, have been regulated by the U.S. Environmental Protection Agency through its National Pollutant Discharge Elimination System (NPDES), which regulates point sources of pollution. The NPDES regulates pollutants such as bacterial toxins, biochemical oxygen demand, metals, industrial pre-treatment, pH Scale and bacteria.

Discharging treated, clean effluent that meets or exceeds regulations is a top policy for the city. Through leveraging taxpayer dollars, federal and state grants, the city has invested millions into its wastewater infrastructure, such as building the wastewater treatment plant on Middle Road that began operation on June 24, 1991, moving it from its previous location in downtown Dover. Currently, work is underway to upgrade the sewer pump station at Payne Street (formerly River Street), which the workhorse of the wastewater system. 

Dover lead the region with improving wastewater treatment system, being among the first to separate stormwater from its sanitary sewer system. The city continues to invest  It continues to seek to reduce stormwater into it system so its not overwhelmed during storm events. 

With the issuance of the Great Bay Total Nitrogen Permit, the EPA also began to regulate nitrogen discharges from the 13 wastewater treatment facilities in New Hampshire within the Great Bay watershed. The permit was issued on Nov. 24, 2020, effective on Feb. 1, 2021 for five years.

The state Department of Environmental Services maintains a page dedicated to the Great Bay estuary. That site includes numerous reports and studies pertaining to the health of Great Bay.

Nitrogen and the Great Bay

The City of Dover recognizes that increased nitrogen levels in the Great Bay estuary are a concern. The City’s approach, along with coalition communities, is to reduce nitrogen levels.

An estuary is where fresh water and sea water mix. It is a dynamic, nutrient rich, diverse environment where many juvenile fish live before venturing into the ocean.

To protect and enhance this important resource, the City of Dover and coalition communities and stakeholders continue efforts lead watershed-wide nitrogen reduction effort.

Researchers estimate that 25 percent of the nitrogen reaching the estuary comes from the wastewater treatment plants.

What can you do to help? 

Seventy five percent of the nitrogen is believed to come from nonpoint sources such as septic systems, fertilizers applied for agricultural and landscaping purposes and stormwater runoff during rain events.

The City of Dover recognizes that action is needed, which is why it supports the AMP and additional scientific solutions to the problem, but at a cost significantly less than what would result from new EPA regulations.

Other science continues to support the City of Dover’s position.

Among the scientific data that aligns with the case made by the Great Bay Municipal Coalition is the recent State of the Estuaries Report by the Piscataqua Region Estuaries Partnership (PREP). PREP is part of the U.S. Environmental Protection Agency’s National Estuary Program, which is a joint local, state and federal program established under the Clean Water Act. PREP's goal is to protect and enhance nationally significant estuarine resources. PREP receives its funding from the EPA and is administered by the University of New Hampshire.

The report affirms the scientific analysis and continuing concerns of the Great Bay Municipal Coalition. In particular, the PREP report makes note of the fact that although dissolved inorganic nitrogen levels have shown a significant increasing trend at Adam’s Point since the mid 1970’s, there are no consistent patterns at other locations. The report shows that although the nitrogen load coming from wastewater treatment facilities within the estuary has remained relatively unchanged over the years there does appears to be a relationship between changing nitrogen load and rainfall.

Perhaps of most significance in the report is the acknowledgement of recent gains in eel grass growth. A declining trend in eelgrass was one of the main indicators upon which the NH Department of Environmental Services identified nitrogen as causing water quality impairment. Throughout the report, the need for additional research and data collection to understand cause and effect relationships impacting various indicators of water quality and the more recent trends and patterns of those indicators in Great Bay is noted.

The State of the Estuaries Report can be viewed here.

All of the most recent PREP reports, including a guide for citizens, can be found at the PREP website at www.stateofourestuaries.org

The Great Bay estuary

Great Bay is a tidal estuary that straddles Rockingham and Strafford counties, stretching from the mouth of the Piscataqua River through Little Bay and into Great Bay at Furbur Strait, the drainage confluence of the Lamprey, Squamscott and Winnicut rivers. The Cochecho, Salmon Falls, Bellamy and Oyster rivers flow into the system between the Furber Strait and the open coast. 

Often dubbed New Hampshire’s “hidden coast,” the Great Bay is unique because it is both a saltwater and freshwater system, or estuary, set apart from the coastline. The Piscataqua River brings salt water into the bay with the tides, an essential element for the growth of plant and animals that live in estuaries. Water levels in the bay are heavily influenced by these daily tides, which expose mudflats at low tide, providing important feeding grounds for birds. In recognition of Great Bay’s beauty, diversity and productivity, the U.S. Environmental Protection Agency has afforded special protection to it as one of only 28 “estuaries of national significance.”

The state Department of Environmental Services maintains a page dedicated to the Great Bay estuary. That site includes numerous reports and studies pertaining to the health of Great Bay.

EPA Nitrogen regulation

Since the passage of the Clean Water Act in 1972, wastewater treatment plants, like Dover's, have been regulated by the U.S. Environmental Protection Agency through its National Pollutant Discharge Elimination System (NPDES), which regulates point sources of pollution. The NPDES regulates pollutants such as bacterial toxins, biochemical oxygen demand, metals, industrial pre-treatment, pH Scale and bacteria.

With the issuance of the Great Bay Total Nitrogen Permit, the EPA also began to regulate nitrogen discharges from the 13 wastewater treatment facilities in New Hampshire within the Great Bay watershed. The permit was issued on Nov. 24, 2020, effective on Feb. 1, 2021 for five years.

The GTNP allowed an adaptive management approach, long championed by Dover and other communities within the Great Bay watershed. In April 2021, the cities of Dover, Portsmouth and Rochester formed Municipal Alliance for Adaptive Management (MAAM) – the same communities that banded together before as the Great Bay Municipal Coalition. The Municipal Alliance allows the members to collaborate with each other, regulators and stakeholders to improve water quality and reduce total nitrogen in the Great Bay estuary, sharing costs and reducing monitoring redundancy. The towns of Newington, Milton, Exeter and Rollinsford have also signed onto the agreement. The Municipal Alliance is open to all communities in the Great Bay watershed.

The Municipal Alliance for Adaptive Management submitted it's Joint Adaptive Management Plan to the EPA in July 2021.

History

In 1998, the EPA published the Clean Water Action Plan: Restoring and Protecting America's Waters to improve the water quality in the nation’s lakes, rivers and estuaries, finding that "polluted runoff is now the leading cause of water quality degradation in most of our surface waters" and that 70% of [the country's] impaired rivers and streams are polluted by agricultural runoff or discharges." The Clean Water Action Plan was to be a "blueprint for restoring and protecting [the country's] water resources. One component of this plan was developing a numeric criteria for nutrients (i.e., nitrogen and phosphorous) in water bodies. The EPA requested each state to develop numeric nutrient criteria for its own water bodies. 

In New Hampshire, the Department of Environmental Services (NHDES) published the "Numeric Nutrient Criteria for the Great Bay Estuary" in June 2009. At the time, the state's water quality standards contained only a narrative criteria for nutrients to protect designated sites. The Piscataqua Region Estuaries Partnership (PREP) facilitated the nutrient criteria development process, forming a technical working group in 2005 to provide input on the methods, and supporting additional research to assist in the development of the criteria. PREP is part of the EPA's National Estuary Program, a joint local/state/federal program established under the Clean Water Act with the goal of protecting and enhancing nationally significant estuarine resources. PREP receives its funding from the EPA and is hosted and administered by the University of New Hampshire.

EPA draft permit 2012

In January 2012, the EPA proposed adding nitrogen discharge limits to Dover's NPDES wastewater treatment plant permit with the issuance of the draft permit. City officials were concerned that city's sewer rates would increase significantly, depending on the nitrogen limit established in the new permit. 

While objecting to the nitrogen limit, the City of Dover continued to encourage, support and lead further study of the science upon which the proposed discharge limits are based. To that end, the City of Dover joined with the cities of Portsmouth and Rochester also affected by the proposed discharge limits, and formed the Great Bay Municipal Coalition. Its goal was to ensure the discharge limits were based on sound science. The Coalition raised concerns about the analysis performed by the NHDES used to establish the “nutrient criteria,” which is the primary document referenced in the EPA mandate to reduce the nitrogen discharge at the Dover wastewater treatment plant to 3 milligrams per liter.

Peer review

In April 2013, the cities of Dover, Portsmouth and Rochester, reached an agreement with NHDES in April 2013 to conduct an independent review of the 2009 DES Nutrient Criteria document that largely influenced the EPA’s proposed significant nitrogen discharge limits for wastewater treatment plants. The DES document, “Numeric Nutrient Criteria for Great Bay Estuary”, analyzes available water quality data from the Great Bay estuary, and proposes nitrogen water quality standards for estuary waters.

The peer review is based on questions posed jointly by all three cities, as well as DES. In framing the review, all parties agreed on the scope of work and jointly selected four recognized experts with extensive expertise on estuarine ecology with no conflicts of interest or previous studies of the Great Bay estuary. In addition, public comments were encouraged from other interested parties, including the EPA and the Conservation Law Foundation.

The final report of the peer review panel was issued on Feb. 13, 2014. The complete report can be viewed here.

The Coalition communities are meeting with NHDES representatives in a cooperative effort to determine how best to move forward based on the conclusions presented in the Peer Review Report.

Before the EPA's issuance of the GBTN, the last permit was issued by the EPA was in 2006, which did not regulate nitrogen. At the time, Dover's wastewater treatment plant nitrogen discharge was 22.5 milligrams per liter (mg/L). 

In 2012, EPA released a draft of a new permit for review. The draft permit included total nitrogen d

Under the terms of the permit, which EPA developed in close coordination with the New Hampshire Department of Environmental Services (NHDES), 13 wastewater treatment plants in 12 New Hampshire communities are eligible for coverage. Those that voluntarily choose to opt into the permit, including Dover, Portsmouth and Rochester, are required to meet seasonal average load limits for total nitrogen designed to protect the estuary from water quality impairments due to excess nutrient loading. As envisioned, the permit is part of a comprehensive federal and state approach that will over time dramatically reduce nitrogen levels in Great Bay.

The Great Bay estuary is composed of a complex network of tidal rivers, inland bays, and coastal harbors. The estuary receives treated wastewater effluent containing nitrogen from 17 WWTFs located in New Hampshire and Maine. Additionally, the estuary receives a significant nitrogen load from a variety of nonpoint sources and stormwater point sources throughout the watershed. Upon an evaluation of years of ambient monitoring data and other relevant technical and scientific information, EPA has determined that the nitrogen load is exceeding the assimilative capacity of the estuary and is causing or contributing, or has the reasonable potential to cause or contribute, to pervasive nutrient-related impairments and violations of water quality standards.

for Dover and other area wastewater plants ot  which seeks to improve water quality and restore damaged ecosystems in the Great Bay estuary by establishing effluent limitations and enhancing monitoring and reporting at 13 wastewater treatment plants in 12 New Hampshire communities to reduce overall levels of nitrogen discharge.

This innovative permit and its adaptive management approach provide flexibility to the municipalities around the Great Bay estuary to reduce nitrogen discharge from both point sources, such as wastewater treatment facilities, and nonpoint sources, such as runoff from lawns and parking lots. This flexible permitting structure allows the municipalities to be good stewards of their financial resources while they continue to make strides to preserve the environment and restore the estuary.