Our Estuaries Story...
Our estuaries have declined due to stress and are losing resilience to sustain themselves in the face of growing pressures. There are a number of contributing factors to consider; some are due to human activity while others are the result of natural processes beyond our immediate control. We must continue to work collaboratively to make our estuaries more resilient to the changes they are experiencing now, and those to come. To explore what makes our estuaries complex and interesting places along with data from our 23 indicators on the health of the Great Bay and Hampton-Seabrook estuaries, scroll down to view more on the pressures facing our system, the conditions of critical resources and water quality, and our management/social responses to these issues.
STRESS & RESILIENCE
Resilience: The capacity of an ecosystem to absorb repeated disturbances or shocks and adapt to change without continually degrading and fundamentally switching to an alternative stable state.
Climate Change
Driving warming waters, sea-level rise, more extreme storms, coastal acidification, and more.
Population Growth
Increasing populations impact our environment in many ways including demand for resources, loss of open space, and increased pollution.
Land Use
Changes in the natural landscape for commercial, residential, and industrial purposes impact our environment. How we make those changes makes all the difference.
The ecosystem stressors above and others will continue. Focusing on resilience means pro-actively looking for ways to strengthen our ecosystem so that, when these stressors occur, our estuaries are better able to resist and recover from disturbance. Learn more in “The Big Picture.”
To help monitor the changes and stresses in the estuary, PREP collects over 1 million data points annually that we combine into a series of indicators that are organized into Pressure, Condition and Response.
PRESSURE INDICATORS
Pressure indicators measure some of the key human stresses on our estuaries.
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Impervious SurfacesImpervious SurfacesIn 2015, 5.6% of the land area of the Piscataqua Region watershed was covered by impervious surfaces. This is an increase of 1,257 acres of impervious cover or 0.2% of the land area since 2010. -
Total Suspended SolidsTotal Suspended SolidsSuspended solids at Adams Point have increased since 1989, but they have decreased at the Great Bay Station since 2002. -
Nutrient LoadingNutrient LoadingSignificant reductions in point source nitrogen loading have and are continuing to occur at municipal wastewater treatment facilities. Non-point source loading has decreased, but low rainfall is a contributing factor.
CONDITION INDICATORS
Condition indicators measure the current state of the conditions in our estuaries.
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Nutrient ConcentrationNutrient ConcentrationTotal nitrogen decreased at Adams Point but increased at the Chapman’s Landing and Lamprey River stations. DIN decreased at the Oyster River and Upper Piscataqua stations while Chapman’s Landing indicates an increasing trend. -
PhytoplanktonPhytoplanktonBased on monthly sampling at low tide, four of the eight stations periodically—though infrequently—exhibit high (>20 ug/L) levels for chlorophyll-a. There are no statistically significant trends. -
Dissolved OxygenDissolved OxygenIn 2015, at the Great Bay and Coastal Marine Laboratory datasondes, dissolved oxygen levels never fell below 6 mg/L. Low dissolved oxygen events occur in all the tidal rivers. There are no clear trends. -
Salt MarshSalt MarshBetween the early 1900s and 2010, over a thousand acres of salt marsh area was lost in the Piscataqua Region watershed. As of 2017, approximately 5,521 acres of salt marsh habitat remain. -
Shellfish Harvest OpportunitiesShellfish Harvest OpportunitiesThe percentage of possible acre-days between 2012 and 2016 was 80% and 66% for the Great Bay and Hampton-Seabrook estuaries, respectively, continuing the long-term trend of gradual increase in acre-days. -
Beach AdvisoriesBeach AdvisoriesAcross the 17 tidal beaches in the Piscataqua Region watershed, beach advisory days occurred less than 1% of beach-days from 2012 to 2016. There are no statistically significant trends. -
Toxic ContaminantsToxic ContaminantsMost concentrations of measured metals and organic chemicals in blue mussel tissue from 1991-2016 are declining or not changing. Mercury and PCB levels remain high enough to merit continued concern. Many emerging contaminants are not yet monitored consistently. -
Migratory FishMigratory FishMigratory river herring returns to the Great Bay Estuary increased 69% between 2012 and 2016; however, river herring returns have sharply declined for the Oyster and Taylor Rivers. No statistically significant trends.
RESPONSE INDICATORS
Response indicators track some key actions we are taking to restore our estuaries.
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Conservation Lands (General)Conservation Lands (General)As of May 2017, 130,302 acres have been conserved (15.5% of the total land area) representing an increase of 5% in new land area coming under conservation (41,555 acres) since 2011. -
Conservation Lands (Focus)Conservation Lands (Focus)In 2017, 34.4% of Conservation Focus Areas (CFAs) in New Hampshire and 14.2% of CFAs in Maine were conserved, for a combined impact of 40.9% of progress toward the PREP goal. -
Oyster RestorationOyster RestorationMore than 26 acres of oyster restoration efforts have taken place since 2011. For recent efforts, the actual area covered by oyster shell has decreased by an average of 63%, while one site increased by 30%. -
Migratory Fish RestorationMigratory Fish RestorationIn 2016, 42% of the historical distribution for river herring in the Piscataqua Region has been restored. Additionally, removal of the Great Dam in Exeter in July 2016 has improved/enhanced river herring passage on the Exeter River.
SOCIAL INDICATORS
Social indicators measure the social landscape that could impact environmental indicators.
