9/9 FRI 11:00 | EPA's Numeric Nutrient Criteria 2
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The Florida Department of Environmental Protection (FDEP) is working on developing numeric nutrient criteria to manage nutrient levels in surface waters, focusing on preserving aquatic ecosystems while responding to a petition to the EPA to rescind previous determinations. The proposed rule emphasizes site-specific analyses to interpret narrative nutrient criteria more accurately, especially given variability and uncertainty in nutrient effects on ecosystems. Public workshops and legislative processes are outlined for future rule development and adoption.
9/9 FRI 11:00 | EPA's Numeric Nutrient Criteria 2
- 1. Florida’s Numeric Nutrient Criteria Development EffortsBy: Florida Department of Environmental Protection Kenny Hayman Senior Assistant General CounselSeptember, 2011
- 2. FDEP Petition to EPAMarch 16, 2011: EPA Memo outlines 8 elements of a State Framework for Nutrient ReductionsApril 22, 2011: FDEP Petitions EPA toRescind Determination to Promulgate Criteria in FloridaRescind Promulgated CriteriaPetition based on Florida performance against the 8 elements and includes initiation of rule development for State standards.EPA’s initial response did not grant or deny.Still lobbying EPA to grant Petition.
- 3. DEP’s Goal for Nutrient RulemakingManage nutrients in surface waters at loadings or concentrations that result in protection and maintenance of healthy, well-balanced aquatic communitiesRule 62-302.530 (47)(b), F.A.C.States, “in no case shall nutrient concentrations of a body of water be altered so as to cause an imbalance in natural populations of aquatic flora or fauna.” Proposed rule numerically interprets the narrative nutrient criteria.
- 4. Conceptual Structure: GeneralThe narrative nutrient criteria would continue to apply to all waterbodies, and numeric interpretations would be applied based on the scientific information available The narrative would be implemented using a systematic structure that numerically interprets the narrative nutrient criteria for each waterbody in a hierarchical manner
- 5. Nutrients Need a New Conceptual ModelNutrients are typically not toxic, and effects on aquatic ecosystems are moderated in their expression by many natural site specific factors light penetration, hydraulic residence time, presence of grazers, and habitat considerations
- 6. Nutrient Expression Is Site-SpecificDEP has extensively studied nutrients in Florida and found there is considerable variability and uncertainty in predicting nutrient effects in many aquatic systemsMakes broad based numeric criteria development more complicated than for most pollutants (e.g., toxic substances) Only statistically weak relationships were found between nutrients and biological effects in streamsWide range of TP and TN can produce same chlorophyll response in lakes
- 7. Guiding Scientific and Policy PrinciplesNumeric interpretations are most accurate when determined as a site-specific functionTherefore, nutrient Total Maximum Daily Loads (TMDLs), Site Specific Alternative Criteria (SSAC), and other site specific actions written to achieve the narrative nutrient criteria should be given preference over more broadly applicable interpretations
- 8. Guiding Scientific and Policy Principles (cont.)Absent site-specific analyses, criteria based on a quantifiable linkage between anthropogenic nutrient enrichment and a biological response can be used to numerically interpret the narrative nutrient criteria
- 9. Guiding Scientific and Policy Principles (cont.)There is value in knowing whether nutrient concentrations are potentially elevated to environmentally harmful levels, but it is important to identify adverse biological effects and determine they are linked to nutrients before deciding that nutrient reductions should be pursued
- 10. FDEP Draft Rule ConceptHierarchy of Site Specific Numeric Interpretation of Narrative Nutrient CriterionNutrient TMDLs, SSACs, and WQBELsCause and Effect Relationships (Lakes & Springs)Reference-based thresholds combined with biological data to evaluate attainmentNarrative standard continues where numeric interpretation is unavailable. (e.g., wetlands, intermittent streams, highly colored lakes)
- 11. Potential Use of Reference ValuesBiology (1)HealthyNot HealthyACDoes not attain Aquatic Life Use Support. Attains narrative nutrient criteria unless stressor ID links adverse effects to nutrients.Meet Threshold Attains narrative nutrient criteria.NutrientsBDDoes not attain narrative nutrient criteria unless stressor ID shows nutrients are not causative pollutant.Attains narrative nutrient criteria. Exceed Threshold(1) If biological data are not available, but nutrient threshold exceeded, water placed on IWR’s “study list”.
- 12. Lakes and Springs CriteriaLakes criteria allows for modified criteria for TN and TP, within a specified range, if chl a is met on annual basis (with minimum data requirements.Numeric criteria for spring vents – 0.35 mg/L (same as EPA)
- 13. Some of the Differences Between FDEP’s Proposal and EPA’s RuleBiological confirmation component for Hierarchy 3 streamsNutrient TMDLs as site specific criteriaFDEP relies solely on the narrative for high colored lakes (i.e. > 140 PCUs) DEP sets forth clear pathway for obtaining site specific alternative criteriaDownstream Protection ValuesConcurrent amendments to Impaired Waters Rule
- 14. Projected ScheduleRule DevelopmentSeptember 13 (Leesburg) and 14 (Tallahassee) – Workshops on Revised Draft LanguageOctober 4, 2011 (Naples) – Workshop on Subset of Estuaries (Clearwater Harbor, Tampa Bay, Sarasota Bay, Charlotte Harbor, the Ten Thousand Islands area, Biscayne Bay, Florida Bay, and the Florida Keys)Rule Making (Undecided)ERC Briefing - November 2011ERC Adoption – December 2011Legislative Ratification – 2012 Session
- 15. Designated Use ReclassificationOn Sept. 6, EPA approved new Class III – LimitedIn 2011, the Florida House proposed significant amendments to Florida’s current designated use structure (Did not pass Senate)
- 16. For More Information:FDEP’s Nutrient Numeric Criteria Development Website:http://www.dep.state.fl.us/water/wqssp/ nutrients/index.htm