Florida Numerical Nutrient Criteria Southwest Florida Water Resources Conference Scott I. McClelland Vice President November 20, 2009

Numeric Nutrient Rules u Numeric Nutrient Rules Born From EPA Requirement (National Strategy for the Development of Regional Nutrient Criteria, June 1998) u 2 nd Highest Cause of Impairments in 305(b) Lists u Nutrient Over-enrichment in Gulf of Mexico u For Those States With Narrative Nutrient Rules, Adopt State Numerical Rules or Use EPA’s Numbers (In Guidance Documents) u State’s Priorities u 1 st : Lakes and Streams (Met 23 Times) u 2 nd : Estuaries (Met 1 Time June 5/6, 2008) u 3 rd : Wetlands (No Meetings Yet)

Numeric Nutrient Rule Technical Advisory Committee (TAC) u Started in 2002 u Membership Representation: u CountiesPrivate River/Lake Experts u Estuarine ExpertsCross-over TAC Member * u UniversitiesEPA Region IV u Lake O ExpertsWater Management Districts u Environmental Interests u Met 24 Times (Including 2 Public Meetings) * Member from Impaired Waters Rule TAC For more information:

Current Florida Narrative Nutrient Standards Chapter (48) “(b) In no case shall nutrient concentration of a body of water be altered so as to cause an imbalance in natural populations of aquatic flora and fauna.” [Classes I, II & III] Complications:  What does “imbalance” mean?  What is the difference between “natural population” and “population resulting from natural conditions”? Or are they the same?

EPA’s Original Approach From Guidance u Based on EPA River/Stream, Lake, Estuary and Wetland Guidance Documents u Uses Level III Ecoregions and All Nutrient monitoring data in STORET (Note: 1/3 rd of all nutrient data in EPA’s STORET is from Florida) Note: It is likely that EPA will use more updated numbers and techniques in future work – these are the only numbers they have published.

IX Southeastern Plain XII Southern Coastal Plain XIII Southern Florida Coastal Plain

Based on 25 th Percentile of All STORET Nutrient Data for Ecoregions IX – Panhandle XII – Central XIII – South FL

Selection of Approach If State Promulgates Numerical Rule u EPA Said To Consider: u Causal Variables – Nitrogen & Phosphorus u Response Variables – Chlorophyll “a” & Turbidity u Preferred “Cause – Effect” Approach u Dose-Response Like Toxics u Reference Site Approach 2 nd Choice u Chose Reference Sites u Characterize Nutrient Concentrations at These Sites  Nutrient Criteria

Consideration of Nutrient Rules u Springs and Spring Runs u Lakes u Streams, Rivers and Canals

Change Point at mg/L Nitrate-nitrite, R 2 = 0.62 Suwannee Periphytometer Change Point Analysis: Cell Density Clear statistical point at which increase in cell density with increase in nitrate plus nitrite nitrogen.

Nitrate-nitrite Conclusions u Lab studies demonstrated nitrate-nitrite was primary factor causing elevated growth at levels above to mg/l u Independent field studies showed imbalances occur at to mg/l nitrate-nitrate u Proposed criterion combines both lines of evidence = 0.35 mg/l u Also applied to clear streams (<40 PCU) PCU = Platinum Cobalt Units

Lakes u Draft Nutrient Criteria for Lakes based on “dose-response” analysis: TN and TP to Chlorophyll a u Chlorophyll a Targets u Colored Lakes (>40 PCU) = 20 µg/l u Clear Lakes (<40 PCU) –High Alkalinity (≥ 50 CaCO 3 ) = 20 µg/l –Low Alkalinity (< 50 CaCO 3 ) = 9 µg/l PCU = Platinum Cobalt Units

Chlorophyll a Colored Lake Chlorophyll a Response to Total Phosphorus Chl-a typically > 20Chl-a typically < 20 Range of Uncertainty

Proposed Lakes Criteria u Measured as Annual Geometric Mean u Below Lower Threshold then Unimpaired u In Between, Check Chlorophyll a

Streams, Rivers and Canals u State attempted “dose-response” analysis without meaningful results, including u Chlorophyll a u Taxonomic composition of macroinvertebrates u Algal communities (frequency & occurrence) u EPA Recommended Next Choice – Reference Stream Approach Note: By “without meaningful results” I mean statistical correlations explained a very small percentage of data variation.

Benchmark Nutrient Regions Used 90 th Percentile of Data from Reference Lakes

Comparison of Results

Issues – Rules & Enforcement u Draft FDEP Rule: u FDEP and EPA approved TMDLs would be listed in draft rule as potential Site Specific Alternative Criteria u EPA to review each approved TMDL as change in WQ criteria u EPA Indicated That Each Parameter Would Be Independently Applied (e.g., for a TN-limited Lake, if Chlorophyll A and TN are less than criteria and TP is above, the Lake would be impaired)

Issues – Implementation Policy u WWTP u AWT Results in 3 mg/l TN & 1 mg/l TP u WW Reuse Wet Weather Discharge u Discharge from Artificial Wetlands u New Draft Florida Stormwater Rule – Undeveloped Lands EMCs are 1.15 mg/l TN and mg/l TP u How The Criteria Are Going To Be Used Is Just As Important As Numbers

Recent Events u EPA Washington settled (signed by EPA on August 19 th ) with Environmental Plaintiffs on Numerical Nutrient Criteria (NNC) u EPA will issue NNC for Florida by January 14, 2010 for lakes and streams and by January 14, 2011 for estuaries

My Opinion u Scientific Justification for: u Springs and Spring Runs (Clear Streams) u Lakes u Limited or No Justification for Streams and Rivers: u Relationships Between Nutrients and Biological Balance Not Found Even Though Florida Has Large Ambient Nutrient Database u Reference Streams Based on Unaffected Conditions Not Lack of Impairment (i.e., Biological Imbalance) u Merit in Numerical Nutrient Criteria for Spring Runs, Lakes and Estuaries

My Recommendation u Set Nutrient Targets Based on Protection and Restoration of Lakes and Estuaries u Set Nutrients in Stream or River: u Based on TMDL-like Analysis To Protect Downstream Lake or Estuary u If Biological Impairment is Measured in the Stream or River, Set Site Specific Nutrient Targets Only if There is a Strong Relationship Between Biological Impairment and Nutrient Inputs

Thank You! Questions?