1. New Hampshire Estuaries Project September 30, 2005 Estuarine Nutrient Criteria Presentation to New Hampshire Estuaries Project Technical Advisory Committee Matthew Liebman, EPA New England

2. New Hampshire Estuaries Project September 30, 2005 “We have a lot of problems, so let’s get started” EPA’s Nutrient strategy –Nutrients are a problem –Identify nutrient and biological levels below which nuisance or impaired conditions are unlikely to occur; thus designated uses are protected –Apply ecoregional reference condition approach, or effects based approach –Adopt criteria into state water quality standards Examples from lakes and streams Factors to think about in developing nutrient criteria Expectations from EPA, a national perspective, and examples from regional/state workgroups

3. New Hampshire Estuaries Project September 30, 2005 Fortunately, there’s a lot of good work in developing lakes and streams ecoregional-based criteria Lakes and streams ecoregional-based criteria (reference conditions) published in 2000 and 2001 EPA established RTAGS to gather data and develop criteria with states, federal agencies and academics EPA/NEIWPCC published more specific recommended ecoregional criteria for lakes and streams in New England www.neiwpcc.orgwww.neiwpcc.org States have developed nutrient criteria plans (mutually agreed to with EPA), they are currently being updated to include estuarine criteria

4. New Hampshire Estuaries Project September 30, 2005

5. New Hampshire Estuaries Project September 30, 2005 The statistical reference condition approach assumes that the reference condition protects uses

6. New Hampshire Estuaries Project September 30, 2005 States can adjust the reference condition with additional information, such as “use impairment”, or effects information [TP] Final State/ Tribal Criterion State/Tribal Refinements Through RTAG Progression from Reference Condition to Criterion Reference Conditions Expert Judgment Modeling Historical Information Downstream Effects

7. New Hampshire Estuaries Project September 30, 2005 Example of effects-based approach for streams: literature nutrients and periphyton biomass regression equations General nutrient-periphyton regression equations were backcalculated to provide TP and TN levels resulting in <100 mg/m 2 chl a biomass: TP = 47 ug/L TN < 0.97 mg/L

8. New Hampshire Estuaries Project September 30, 2005.1 1 10 100 1000 open closed Reference Moderately Impaired Milligrams per meter squared Example of effects-based approach for streams: Periphyton chlorophyll a (10) (10) Number of samples (Source: USGS, EPA)

9. New Hampshire Estuaries Project September 30, 2005 0.1.2.3.4.5.6 0 1 2 3 4 5 6 7 8 Milligrams per liter 10th25th 50th75th 90th Percentile 10th25th 50th75th 90th Percentile Subecoregion 59.024 mg/L Subecoregion 59 0.57 mg/L 0.037 mg/L 0.75 mg/L Total Phosphorus Impaired Sites Total Nitrogen Impaired Sites (Source: USGS, EPA)

10. New Hampshire Estuaries Project September 30, 2005 Factors to consider in development of nutrient criteria Identify nutrient and biological levels below which nuisance or impaired conditions are unlikely to occur; thus designated uses are protected Criteria should be developed for different uses, e.g. aquatic life, recreation Consider both causal and response variables Consider an index period, such as summer June to September Classify estuaries to reduce variance, develop criteria for each class Consider concentration or loading based approaches Reference condition approach or effects-based approach Availability of current or historical data Apply modeling results or literature values Develop consensus criteria

11. New Hampshire Estuaries Project September 30, 2005 National perspective of estuarine nutrient criteria Estuarine guidance manual published in 2001 proposes several approaches to criteria development HQ has set up a national workgroup with academics, feds and state scientists to assist in development of estuarine nutrient criteria. One of first tasks is to select a “pilot” group of estuaries for criteria development, including 10 from the Gulf of Mexico, and 10 other estuaries (including Delaware Bay and Peconic Bay) –uses a classification scheme of nutrient susceptibility developed by NOAA –approach depends on availability of data Will select other “pilot” estuaries in near future –Selection factors include availability of data, approach for criteria development, whether systems are multi-state or effluent dominated systems, degree of nutrient enrichment –Goal is to publish criteria for these systems by 2007 Coastal (not estuarine) nutrient criteria workgroup meeting in Delaware October 24 and 25 to review coastal nutrient criteria manual

12. New Hampshire Estuaries Project September 30, 2005 There are several ongoing work groups or efforts to develop estuarine nutrient criteria in New England Massachusetts Estuaries Project –Contact Brian Dudley, MA DEP, brian.dudley@state.ma.us, 508/946- 2753, http://www.oceanscience.net/estuaries/index.htm brian.dudley@state.ma.us http://www.oceanscience.net/estuaries/index.htm –Using a combination of modeling and effects based approach, nitrogen concentrations related to eelgrass habitat, residence time is a normalizing factor EPA NHEERL –AED –Contact Jim Latimer CT Long Island Sound embayments –Contact Paul Stacey CT DEP New Hampshire Estuaries Project –Contact Phil Trowbridge

13. New Hampshire Estuaries Project September 30, 2005 89 Embayments for Massachusetts Estuaries Project

14. New Hampshire Estuaries Project September 30, 2005 NHEERL Effects-based approach

15. New Hampshire Estuaries Project September 30, 2005 Classification and comparison among estuaries in Long Island Sound River dominated Small embayment

16. New Hampshire Estuaries Project September 30, 2005 Can you choose a reference condition in Great Bay?

17. New Hampshire Estuaries Project September 30, 2005 Factors to consider in development of nutrient criteria Identify nutrient and biological levels below which nuisance or impaired conditions are unlikely to occur; thus designated uses are protected Criteria should be developed for different uses, e.g. aquatic life, recreation Consider both causal and response variables Consider an index period, such as summer June to September Classify estuaries to reduce variance, develop criteria for each class Consider concentration or loading based approaches Reference condition approach or effects-based approach Availability of current or historical data Apply modeling results or literature values Develop consensus criteria