There is consensus among the communities surrounding the Great Bay, including the Great Bay Municipal Coalition communities, that environmental signs indicate a decline in the Great Bay’s water quality and excess nutrients are a contributing factor. It is also apparent that there is agreement among the Great Bay communities, New Hampshire Department of Environmental Services (DES), and the Environmental Protection Agency (EPA) that the science performed to date contains inherent uncertainty and that refinement is needed to better understand the true nature of the water quality problems and identify the actual sources of nutrient pollution.
As an alternative to challenging the uncertainty, Durham has chosen to build on areas of agreement to find common ground and work within the existing regulatory framework to develop an integrated watershed management approach following the EPA’s October 2011 policy on Achieving Water Quality Through Integrated Municipal Stormwater and Wastewater Plans. The Town of Durham has reached out to DES and the EPA to work collaboratively on developing an integrated watershed management plan for the Oyster River Watershed in accordance with this new policy, and based on our recent discussions with them we are encouraged that through cooperation and innovation we will successfully improve water quality and economically meet our Clean Water Act obligations.
As host community to the University of New Hampshire (UNH), the Town of Durham will be partnering with UNH in this endeavor to reduce its shared discharge of excess nutrients and other pollutants from both point and non-point sources while being economically and socially responsible to the community. Assessing and quantifying the progress along the way through a comprehensive water quality monitoring plan will be a critical step in determining compliance with both Durham’s NPDES wastewater permit and the town’s and UNH’s MS4 stormwater permits while continuing to refine the science.
Shortly after Durham’s last NPDES wastewater permit was issued in 1999, the town started taking proactive measures at its wastewater treatment plant by going beyond its NPDES permit requirements and incorporating nutrient removal capabilities through a series of infrastructure and operational upgrades. As a result, Durham’s treatment plant now removes nitrogen to levels below 8 miligrams per liter on average and plans are underway to design and implement another set of upgrades to remove Nitrogen to levels below 5 mg/l.
The EPA has indicated that in order to reverse the Great Bay’s water quality decline, a nitrogen discharge limit of 3 mg/l will be necessary for the Durham treatment plant as well as all other treatment plants discharging into the Great Bay. While a seemingly small difference, the physical and technological reality is that reducing nitrogen levels from 5 mg/l to 3 mg/l is exponentially more expensive and pushes the limits of treatment technology.
And because this small, incremental step typically requires the use of large quantities of expensive chemicals which also are hazardous to transport and store on site, it is not considered a sustainable practice.
As an alternative, Durham has proposed to the EPA to allow the equivalent of the balance of nitrogen between 5 and 3 mg/l in the wastewater treatment plant effluent to be removed through non-point source improvements in the Oyster River watershed. This equates to removing about 1.5 tons of nitrogen annually from the watershed, and we are in the process of hiring a team of engineers and scientists to ensure that this can be done economically. This approach satisfies the intent of the Clean Water Act and is consistent with nutrient trading programs in other New England areas such as Long Island Sound and the Connecticut River Valley.
We believe it should not matter how and where exactly the pollutants are removed as long as the necessary overall reduction is achieved to protect the Great Bay. The EPA is currently evaluating how this innovative approach might be written into the NPDES permits and we are extremely encouraged by the agreeable discussions we have had recently with the EPA staff. Durham and UNH believe that the combination of advanced and technically reasonable wastewater treatment and watershed non-point source management is a balanced approach to protecting and sustaining the Great Bay habitat and we hope that this approach could be easily translated throughout the Great Bay Watershed.
Regardless of which solutions are ultimately adopted by communities within the Great Bay Estuary region, we believe that implementation must occur sooner rather than later to preserve a cherished natural resource.
Todd I. Selig has been administrator for the Town of Durham since 2001.