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Numeric nutrient criteria
Posted on 11/8/2011
- Total maximum daily loads (TMDLs) for nutrients have been established by the Florida Department of Environmental Protection (DEP) for numerous waterways in Florida.
- Florida’s existing nutrient standard, which is a narrative (non-numeric) standard, prohibits any alteration of nutrient concentrations that would cause an imbalance in natural populations of aquatic flora and fauna. These TMDLs interpret the narrative nutrient criteria and are used to set site-specific numeric nutrient concentration goals and nutrient loading limits.
- Using the existing standard, St. Johns River Water Management District staff have worked with DEP and the U.S. Environmental Protection Agency (EPA) in the development of TMDLs.
- After working with the state for a number of years to develop numeric criteria to limit nutrient pollution, EPA was sued by the Florida Wildlife Federation, which argued that EPA had an obligation to promulgate the standards itself until the state acted. EPA was placed on a court-ordered schedule to adopt numeric standards for phosphorus and nitrogen pollution for coastal and estuarine waters.
- In early 2009, EPA determined numeric limits of nitrogen and phosphorus pollution were necessary, whether issued by the state or EPA.
- In response to the lawsuit, EPA is setting numeric nutrient standards in two stages — one rule for inland water bodies outside of the South Florida Region (established in the fall of 2010) and a second rule for estuaries, coastal waters and flowing waters in the South Florida Region. Implementation of the inland water bodies rule was delayed for 15 months. The date for the proposal of estuaries and coastal waters rule is extended to March 15, 2012.
- However, EPA recognizes that states have the primary role in establishing and implementing water quality standards for their waters.
- Most recently, EPA has stated its support of DEP’s commitment to recommence its rulemaking efforts for both inland and estuarine waters. EPA says it is prepared to withdraw the federal inland standards if DEP adopts, and EPA approves, its own protective and scientifically sound numeric standards.
- Currently, DEP is moving forward with draft rules to develop numeric nutrient standards for Florida’s waterways, setting limits on the amount of phosphorus and nitrogen allowed in Florida’s waters.
- In addition, EPA also has said it will adjust the timetables for implementing the inland rule and proposing its own estuarine and coastal waters rule if DEP’s rulemaking efforts progress in accordance with DEP’s proposed schedule to avoid overlap with the final stages of the state rulemaking process.
- The District supports the efforts of DEP and EPA to reduce nutrient pollution and intends to continue serving as a scientific resource in a collaborative process.
- Natural background levels of nutrients vary widely across Florida’s thousands of water bodies. The District agrees that it is essential that nutrient standards preserve this natural diversity. It is the District’s desire that the final rule be based on sound science and protect the diversity of Florida’s ecosystems.