Monday, February 23, 2009

Stormwater and Great Bay

The Newington Conservation Commission meets jointly this evening with the Planning Board and the UNH Stormwater Center to discuss amending Newington's site plan regulations to address pollution from storm water runoff in the Piscataqua River and the Great Bay estuary.

Storm water runoff is likely the leading cause of pollution in Great Bay and in New Hampshire in general, which has caused declines in the health of the Great Bay estuary. The problem is significant: According to one indicator, eel grass populations have declined by 97% in recent years.

The problems caused by Storm Water pollution are well documented. Below is an excerpt from the Conservation Commission report which will be published in the 2008 Town Report:

Stormwater Pollution.
Stormwater runoff from urbanized (i.e. paved) areas is the leading source of non-point pollution in New Hampshire.[1] Stormwater causes pollutants and particulate matter containing heavy metals, hydrocarbons (oil and grease) and organic waste to flow directly to surface waters with little or no treatment. It also increases temperature, nutrient, turbidity and bacteria levels and reduces dissolved oxygen. Studies cited by the NH Department of Environmental Services (NHDES) indicated that surface water quality declines sharply when as little as 10% of a watershed is covered by impervious surfaces.[2] In sections of Newington’s commercial and industrial zones, such as in the Paul’s Brook Watershed, imperviousness already exceeds 40%.

In August of 2008, the NHDES determined that water quality in the Great Bay estuary, and in particular the Piscataqua River and Little Bay, is impaired due to the loss of eelgrass habitat due to high nitrogen and turbidity levels.[3] In addition, 2.6 square miles of tidal estuary in New Hampshire does not meet Class B standards due to stormwater pollution.[4]
Amendments to site plan regulations effect only commercial and industrial development, and should not impact residential development in Newington.

The Planning Board is the agency that will adopt the final regulations and has the final authority to approve any regulations. However, the Planning Board has asked the Conservation Commission to take the lead in developing the proposed regulations. Any person wishing to comment on storm water issues should contact the Newington Conservation Commission or come to our meetings, normally held the second thursday each month.


[1] See e.g., Nonpoint Source Management Plan, Table 2.3, Page 2.2.4 (October 1999).
[2] See e.g., Best Management Practices to Control Nonpoint Source Pollution: A Guide for Citizens
and Town Officials, Page 9 (January 2004); NH Estuaries Project State of the Estuaries 2006; Deacon et al., Effects of Urbanization on Stream Quality at Selected Sites in the Seacoast Region in New Hampshire, 2001–03.
[3] Methodology and Assessment Results related to Eelgrass and Nitrogen in the Great Bay Estuary
for Compliance with Water Quality Standards for the New Hampshire 2008 Section 303(d) List, NHDES WD Doc R-WD-08-18 (August 2008).
[4] 2004 Section 305(b) and 303(d)Surface Water Quality Report, Table 3-5, Page 3-10 (March 31, 2004).