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Review of Methods and Approaches for Deriving Numeric Criteria for Nitrogen/ Phosphorus Pollution in Florida's Estuaries, Coastal, and Soutnern Inland Flowing Waters
Impact/Purpose:
The SAB is asked to evaluate the draft document, Methods and Approaches for Deriving Numeric Criteria for Nitrogen/Phosphorus Pollution in Florida’s Estuaries, Coastal Waters, and Southern Inland Flowing Waters, and respond to the following charge questions.
Description:
EPA will propose numeric criteria for nitrogen/phosphorus pollution to protect estuaries, coastal areas and South Florida inland flowing waters that have been designated Class I, II and III , as well as downstream protective values (DPVs) to protect estuarine and marine waters. In accordance with the formal determination and pursuant to a subsequent consent decree, these numeric criteria are being developed to translate and implement Florida’s existing narrative nutrient criterion, to protect the designated use that Florida has previously set for these waters, at Rule 62-302.530(47)(b), F.A.C. which provides that “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.” Under the Clean Water Act and EPA’s implementing regulations, these numeric criteria must be based on sound scientific rationale and reflect the best available scientific knowledge. EPA has previously published a series of peer reviewed technical guidance documents to develop numeric criteria to address nitrogen/phosphorus pollution in different water body types. EPA recognizes that available and reliable data sources for use in numeric criteria development vary across estuarine and coastal waters in Florida and flowing waters in South Florida. In addition, scientifically defensible approaches for numeric criteria development have different requirements that must be taken into consideration in the context of the specific application and available information. This document describes the scientific approaches EPA is considering the derivation of numeric criteria to address nitrogen/phosphorus pollution in Florida estuarine and coastal waters, and inland flowing waters in South Florida, given the available data currently available. In addition, the implementing regulations of the CWA (40 CFR 131.10(b)) state that: “In designating uses of a water body and the appropriate criteria for those uses, the State shall take into consideration the water quality standards of downstream waters and shall ensure that its water quality standards provide for the attainment and maintenance of the water quality standards of downstream waters.” In November 2010, EPA established criteria for Florida’s lakes, flowing waters and springs within the State of Florida, including DPVs for lakes. These promulgated criteria only apply to predominantly fresh surface waters and implement the State’s narrative nutrient criterion mentioned above. As part of this effort to derive chlorophyll-a, total nitrogen (TN) and total phosphorus (TP) criteria to protect estuarine and coastal water bodies, EPA must also develop additional criteria to assure that upstream criteria will meet standards established for downstream estuarine and marine waters in Florida. These DPVs, will supplement existing inland water TN and TP stream criteria, if the applicable DPV is more stringent. Review Document: The SAB is asked to evaluate the draft document, Methods and Approaches for Deriving Numeric Criteria for Nitrogen/Phosphorus Pollution in Florida’s Estuaries, Coastal Waters, and Southern Inland Flowing Waters, and respond to the following charge questions.