Waquoit Bay Watershed Ecological Risk Assessment: the Effect of Land-Derived Nitrogen Loads on Estuarine Eutrophication
Contact
- Patti Tyler
- by phone at: 303-312-6081
- by email at: tyler.patti@epa.gov
- by email at: tyler.patti@epa.gov
A nitrogen loading model (NLM) was used to estimate the amount and sources of nitrogen entering the watershed, and an estuarine loading model (ELM) was used to estimate the nitrogen available to producers in shallow estuaries. The NLM indicates that atmospheric deposition is the largest source of nitrogen, but because more atmospheric nitrogen than wastewater nitrogen is intercepted in the watershed, wastewater becomes the largest contributor of nitrogen reaching the bay. By comparing increases in nitrogen loads to losses in the area of eelgrass cover over the last 60 years, it appears that eelgrass disappears once nitrogen loads reach 20 kg/ha/yr. Both the increase in nitrogen load and the decrease in eelgrass can be correlated to decreases in the annual harvest of scallops. The models provide the opportunity for managers to assess a variety of options to reduce nitrogen loads to their estuaries and to achieve the loads that could allow the return of eelgrass to the target area.
Downloads/Related Links
- Waquoit Bay Watershed Ecological Risk Assessment: the Effect of Land-Derived Nitrogen Loads on Estuarine Eutrophication (PDF) (NA pp, 2 MB, about PDF)
Related Link(s)
Additional Information
The U.S. Environmental Protection Agency thanks the following for their participation in this case study:
- Waquoit Bay National Estuarine Research Reserve
- Association for the Preservation of Cape Cod
- Cape Cod Commission
- Citizens for the Protection of Waquoit Bay
- Massachusetts Coastal Zone Management
- Massachusetts Dept of Environmental Protection
- National Marine Fisheries Service
- National Oceanic and Atmospheric Administration
- US Army Corps of Engineers
- US Fish and Wildlife Service
- Waquoit Bay Watershed Intermunicipal Committee
- US Geological Survey
- Massachusets Division of Fisheries and Wildlife
- Buzzards Bay Project
- Town of Mashpee
- Town of Falmouth
Citation
U.S. EPA. Waquoit Bay Watershed Ecological Risk Assessment: the Effect of Land-Derived Nitrogen Loads on Estuarine Eutrophication. U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Washington Office, Washington, DC, 600/R-02/079, 2002.