New York, like many other states, is working with the United States Environmental Protection Agency (USEPA) to develop more specific numeric criteria that better define the levels of nutrients that result in impairment of water uses. Numeric criteria provide more definitive nutrient thresholds for the regulation of nutrients in NYS waters.
Nutrients: The Problem
Nutrients (phosphorus and nitrogen) are a natural part of healthy lakes, rivers, streams and estuary ecosystems. However, excessive nutrients can cause water quality problems that negatively affect water supplies, recreational uses and aquatic life.
Nutrient enriched river with floating algae mats.
Photo: Jim Swart, DEC
High levels of nitrogen and phosphorus in waters can produce nuisance algal blooms and increase aquatic weed growth.
Excessive algal and weed growth reduces:
- water clarity
- recreational value of a waterbody
- oxygen in the water and can produce "dead zones" where dissolved oxygen levels drop so low that aquatic life cannot survive
Point and nonpoint sources of nutrient enrichment and eutrophication to streams, lakes, and estuaries include:
- Agricultural activities that result in animal waste and sediments washing into waterbodies
- Urban runoff from impervious surfaces (parking lots, lawns, rooftops, roads)
- Inadequate onsite septic system
- Municipal wastewater treatment plant discharges
- Atmospheric deposition
Nutrients are regulated in New York State Waters by a narrative water quality standard rather than a numeric standard. A numeric standard provides a specific numeric threshold (e.g., mercury not more than 0.0007 ug/L), and a narrative standard lays out a descriptive condition that needs to be met. The narrative standard for phosphorus and nitrogen is: None in amounts that result in the growths of algae, weeds and slimes that will impair the waters for their best usages.
Developing specific numeric criteria for nutrients is complicated by a number of factors:
- Nutrients are naturally occurring and everywhere in our environment, so more stringent criteria are expected to affect many activities, stakeholders, and regulatory programs.
- Some level of nutrients is necessary for a healthy ecosystem and appropriate levels of nutrients vary from waterbody to waterbody, depending on a variety of characteristics (for example, depth, streamflow, water temperature, etc).
- Elevated nutrient levels by themselves do not normally cause direct impairment (except at extremely high levels), but rather they can produce conditions, such as reduced clarity, weed/algal growth, and low dissolved oxygen, that can impair aquatic life, water supplies and recreational uses.
Because of these complicating factors and the impact numeric nutrient criteria are likely to have across the state, New York is taking an intentionally deliberate approach to developing these criteria. DEC will evaluate and communicate the implications, to insure that the final plan will be effectively and successfully implemented.
Current Nutrient Reduction Efforts
The Numeric Nutrient Criteria will build on work that New York has already taken to reduce nutrients in lake, rivers, streams and estuaries:
- Total Maximum Daily Load (TMDL) plans are watershed-based pollutant reduction strategies that have been established for many high-profile nutrient-impacted watersheds, such as Lake Champlain, Susquehanna (Chesapeake Bay), and Long Island Sound.
- Municipal Separate Storm Sewer Systems (MS4) program requires practices to reduce nutrients and other pollutants from stormwater discharges and impervious surface runoff.
- Concentrated Animal Feeding Operations (CAFO) program requires best management practices to limit nutrient runoff from agricultural activity.
- The State Pollutant Discharge Elimination System (SPDES) regulates all discharges of wastewater to lakes, rivers and streams and requires all dischargers to meet standard treatment levels.
- Water Quality Based Effluent Limits (WQBELs) can require dischargers to reduce nutrients beyond standard treatment levels where necessary to protect water quality and recreational uses.
- Numeric guidance for total phosphorus, a value of 20 ug/L, is already in place for most lakes and reservoirs in the state.
- Dishwasher Detergent and Nutrient Runoff Law are in place banning phosphorus-based detergents and lawn fertilizers statewide.
NYSDEC is currently working to identify nutrient criteria values - initially focusing on phosphorus in fresh waters-that are protective of water quality in New York State. The Department is aware of the impact that more strict nutrient controls could have on the regulated community and will develop an implementation strategy that recognizes the need to phase in new criteria over time. We are working toward release of the scientific and technical basis for the draft specific criteria as well as related implementation plans sometime in 2013, with release of a formal nutrient criteria proposal possible in late 2013. As these efforts move forward, NYSDEC will conduct public outreach to inform stakeholders and solicit their feedback.
The current version of the New York State Nutrient Standards Plan (PDF) (127 KB)for the development of numeric nutrient criteria can be found on the NYSDEC website. This Plan, initially focusing on phosphorus in fresh waters, has been developed in consultation with, and mutually agreed upon by the USEPA. A Table of Milestones for Nutrient Criteria, revised June 16, 2015 (25 KB)addends and updates the milestones in the 2011 plan.