Growing Threats

Regrettably, as a result of multiple stressors – primarily related to population growth and low-density sprawl – the health of the estuary is in jeopardy. There is concern among scientists that Great Bay is approaching a tipping point which, once crossed, will make its recovery incredibly challenging and costly. The indicators of decline include:

• Nitrogen pollution from sewage treatment plants, stormwater and other sources, which has increased significantly in recent years, and which causes algae blooms and loss of water clarity;

• Eelgrass, the cornerstone of the ecosystem, which has declined substantially in Great Bay in the past decade, which in recent years has virtually disappeared in the Piscataqua River and Little Bay, and which is no longer present in places it historically existed in the Squamscott, Oyster, Bellamy and Lamprey Rivers;

• Oysters, which are important for water quality and recreational harvesting, which were decimated by harmful pathogens in the 1990s and which have been very slow to recover; and

• Impervious surfaces, such as roads and parking lots, which, as a result of intense sprawl development, have increased substantially in New Hampshire’s coastal watershed (from 28,710 acres in 1990 to 50,351 acres in 2005).

CLF has been working to reverse these trends and has, in some key areas, advanced strong solutions. To find out more about CLF’s success, click here.