Strafford News

The Conservation Law Foundation recently submitted a petition to the U.S. Environmental Protection Agency for the agency to exercise its residual designation authority to regulate stormwater discharges into the Great Bay Estuary. The CLF alleges that non-point stormwater discharges are contributing to the violations of water quality standards in the Great Bay Estuary watershed.

The CLF’s petition and statements of fact, filed on Feb. 15, 2023, is available here. By law, the EPA is required to respond to the petition within 90 days. The City of Dover is currently studying the petition and has not taken a position.

The EPA’s “residual designation” authority stems from the federal Clean Water Act. It allows the agency to regulate stormwater discharges on a case-by-case basis if it determines the discharges contribute to a violation of water quality standards, is a significant contributor of pollutants to federally protected surface waters, or controls are needed for the discharge based on the waste load allocations that are part of “total maximum daily loads” that address the pollutant(s) of concern.

“Exercising its residual designation authority will allow EPA to regulate currently unregulated discharges of nitrogen that are harming the estuary,” the CLF states. “Existing mechanisms, including the Great Bay Total Nitrogen General Permit and New Hampshire Small Municipal Separate Storm Sewer System General Permit, control for some nitrogen in the estuary, but are limited in scope and application and do not address most of the nitrogen affecting the estuary.”

Non-point sources would include stormwater runoff from impervious surfaces. CLF, in its statement of facts, states, “the average annual nitrogen loading from impervious surfaces ranges from 10.5 to 17 pounds per acre per year, depending on land use type.” Impervious surfaces can also absorb and emit heat and increase the stormwater runoff temperature, thereby “heating the water in the estuary,” the CLF states.

If the EPA agrees to exercise its residual designation authority, the regulation is not expected to affect the Great Bay Total Nitrogen General Permit (GBTNP) the EPA issued in January 2021. The City of Dover agreed to be covered by the permit, which measures point sources of nitrogen, specifically from the city’s wastewater treatment plant on Middle Road. With the cities of Portsmouth and Rochester and the towns of Exeter, Rollinsford, and Milton, and in collaboration with CLF, Dover is participating in the development and execution of an adaptive water quality management plan based on science-based protocols to improve the health of Great Bay.

As it has for years, the City of Dover continues to invest in its wastewater infrastructure to improve the water quality discharging from the wastewater treatment plant. In addition to wastewater plant upgrades, the city continues to seek and fix the inflow and infiltration of stormwater into the sanitary sewer system. The city also regularly evaluates and implements innovative best management practices with stormwater to filter and treat stormwater where it occurs. These ongoing efforts have significantly reduced the amount of nitrogen and other pollutants entering Great Bay.

As part of being covered by the GBTNP, the cities of Dover, Portsmouth, and Rochester committed to the CLF through a settlement agreement to improve water quality in Great Bay, specifically through increased investment in stormwater treatment. At the direction of the City Council, city staff is creating a framework for a stormwater utility to generate a stable source of revenue to improve stormwater infrastructure through user fees and incentivize prudent onpremise stormwater management to reduce pollutants entering Great Bay. As currently envisioned, revenue would be collected through user fees based on a property’s stormwater management practices that could only be spent on stormwater and flood resilience-related activities. A draft ordinance of a stormwater utility is anticipated later this year.

Original source can be found here.