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Research & Monitoring

Status & Trends

LISS Ecosystem Targets and Supporting Indicators

Nitrogen Loading

Attain wastewater treatment facility nitrogen loading at the recommended 2000 Dissolved Oxygen Total Maximum Daily Load allocation level by 2017 and maintain the loading cap. Have all practices and measures installed to attain the allocations for stormwater and nonpoint source inputs from the entire watershed by 2025.

* Click labels in legend to hide data and adjust scale
Progress

The progress bar refers to the first half of the target. Data is not yet available for the second half of the target – reducing nitrogen from nonpoint source and stormwater inputs.

Trade Equalized (TE) Nitrogen Loads Discharged from CT/NY Wastewater Treatment Plants
Connecticut New YorkTotal (TE Pounds/Day)2017 CT/NY Goal
Baseline26,04333,10559,14822,775
199519,56123,66043,22122,775
199621,28728,66249,94922,775
199720,26929,24049,50922,775
199821,71824,26145,97922,775
199921,50823,32444,83222,775
200020,26223,66043,99222,775
200117,10124,34541,44622,775
200215,85523,32639,18122,775
200316,57426,00742,58122,775
200414,34525,62139,96622,775
200515,05526,64941,70422,775
200614,73826,29841,03622,775
200713,49525,37639,23122,775
200813,31127,12840,43922,775
200911,81927,19239,01122,775
20109,99123,79233,70322,775
201111,01422,86433,87822,775
20128,51320,32528,83822,775
20138,44618,70227,14822,775
20148,89915,96224,96122,775
20158,37814,51322,89122,775
20167,17113,22920,40022,775
20177,23312,32419,55722,775

Status and Trends

The 2000 Total Maximum Daily Load (TMDL) agreement between EPA and the states of Connecticut and New York called for a 60 percent reduction from the baseline level of 59,000 trade equalized pounds per day of nitrogen. As of 2017 this goal has been met and even exceeded. Total nitrogen loading to Long Island Sound also has been reduced by more than 45 million pounds per year.

Challenges

The second half of the target addressing stormwater and nonpoint source inputs will be more challenging since such inputs are widely dispersed.

An expanded EPA nitrogen strategy for Long Island Sound focuses not only on the nitrogen inputs from wastewater treatment plants, but also on the nonpoint contributions from tributaries and embayments. It also looks at ecological endpoints beyond hypoxia, such as eelgrass acreage, as increased eelgrass coverage is dependent on good water quality. An initial effort to develop nonpoint source tracking was summarized in a 2014 report (see Final Report link, data notes below)  which evaluates existing nonpoint source tracking tools for their applicability to Long Island Sound. This report suggested the adoption of the Chesapeake Bay Assessment and Tracking Tool (CAST) for use in Long Island Sound.  The report also outlines four tasks to be completed to allow CAST to be applied to the various sub-basins of the Long Island Sound watershed.

How is This Target Measured?

Nitrogen loading from wastewater treatment facilities is reported by the states of Connecticut and New York.

The nitrogen loading reported by Connecticut and New York is called trade-equalized because the amounts are corrected for the impacts of particular wastewater treatment facilities based on their location (see trade equalized nitrogen zones, sidebar).  The information needed for nonpoint nitrogen source controls will be produced by the tracking tools and models currently under development as described under Challenges.

Importance

Nitrogen is a plant nutrient. Large amounts of nitrogen loads into Long Island Sound can stimulate an excessive growth of plant plankton and macroalgae in a process called eutrophication.  

When plankton or microorganisms that eat the plankton decay, oxygen is consumed by bacteria and the bottom waters can become “hypoxic,” with less than 3.0 mg/l of oxygen. This can lead to stress or suffocation for slow moving animals, and cause other animals to scatter. Harmful algal blooms, some of which are toxic to humans, are another potential result of eutrophication.

Nitrogen typically comes from point sources, large fixed sources like wastewater treatment or industrial plants, or non-point sources, smaller diffuse sources like septic systems, stormwater, and agricultural runoff.

Contact

Dr. James Ammerman, Long Island Sound Study james.ammerman@longislandsoundstudy.net

 

Source of Data

Connecticut Department of Energy and Environmental Protection (CTDEEP) and New York State Department of Environmental Conservation (NYSDEC).

 

 

Data Notes

  • The technical explanation on how the target was selected is found in Appendix B of the Comprehensive Conservation and Management Plan.
  • 2014 Final Report: An Evaluation of Nonpoint Source Pollution Control Measure Tracking Systems for Long Island Sound, prepared for the New England Interstate Water Pollution Control Commission by WaterVision, LLC, 30 pages.Open pdf.
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Related Ecosystem Targets

Learn More

Trade equalized nitrogen zones in CT and NY. The calculated impact of nitrogen inputs declines with increased distance from the Western Sound. see tmdl map description

 

Spotlight

Hunts Point wwtp: 42″ sludge pipe at West Aeration Tanks  Credit: NYCDEP

New York City has spent $1 billion to upgrade four wastewater treatment plants that has resulted in a 60 percent reduction in the amount of nitrogen being discharged into the Upper East River. These significant upgrades are helping the states of New York and Connecticut to meet their goal of preventing more than 45 million pounds of nitrogen a year from being discharged into Long Island Sound. See Jan. 5, 2017 news release from New York City Department of Environmental Protection. 

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