Florida Administrative Code › 62 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 62 - Departmental › Chapter 62-303 - IDENTIFICATION OF IMPAIRED SURFACE WATERS › Part IV - THE VERIFIED LIST › Section 62-303.450 - Assessments of Numeric Interpretation of Narrative Nutrient Criteria

Current through Reg. 50, No. 138; July 16, 2024
(1) A stream or estuary without applicable
				  numeric criteria in subsection
				   62-302.531(2),
				  F.A.C., shall be placed on the Verified List for impairment due to nutrients if
				  it exceeds the chlorophyll
a
thresholds in subsection
				   62-303.351(4),
				  F.A.C., or subsection
				   62-303.353(2),
				  F.A.C., more than once in any consecutive three year period, and there are
				  sufficient data from the last 7.5 years to meet the data sufficiency
				  requirements of subsections
				   62-303.350(2) 
				  -(6), F.A.C. If there are insufficient data, additional data shall be collected
				  as needed to meet the requirements. Once these additional data are collected,
				  the Department shall determine if there is sufficient information to develop a
				  site-specific chlorophyll
a
threshold that better reflects
				  conditions beyond which an imbalance in flora or fauna occurs in the water
				  segment. If there is sufficient information, the Department shall re-evaluate
				  the data using the site-specific thresholds. If there is insufficient
				  information, the Department shall re-evaluate the data using the thresholds
				  provided in subsections
				   62-303.351(4) 
				  and  62-303.353(2),
				  F.A.C., for streams and estuaries and verify impairment if there is more than
				  one exceedance in any consecutive three year period. In any case, the
				  Department shall limit its analysis to the use of data collected during the
				  last 7.5 years. If alternative thresholds are used for the analysis, the
				  Department shall provide the thresholds for the record and document how the
				  alternative threshold better represents conditions beyond which an imbalance in
				  flora or fauna is expected to occur.
(2) If the waterbody was listed on either the
				  Planning or Study List for nutrient enrichment based on other information
				  indicating an imbalance in flora or fauna, as provided in paragraphs or
				  subsection  62-303.350(1),
				   62-303.351(3),
				   62-303.352(1)(b) 
				  or  62-303.353(3),
				  F.A.C., the Department shall verify the imbalance before placing the water on
				  the Verified List for impairment due to nutrients and shall provide
				  documentation supporting the imbalance in flora or fauna.
(3) If the waterbody was listed on the
				  Planning List based on paragraphs or subsections
				   62-303.351(1),
				   62-303.352(1)(a) and
				  (d),
				   62-303.353(1) and
				  (5), or
				   62-303.354(1),
				  F.A.C., the Department shall place the waterbody on the Verified List for
				  exceedances of the narrative nutrient criteria in paragraph
				   62-302.530(47)(b),
				  F.A.C., if the applicable numeric interpretation of the narrative nutrient
				  criterion is exceeded based on the last 7.5 years of data.
(4) If a lake was listed on the Planning List
				  based on subsection  62-303.352(2),
				  F.A.C., and there are still insufficient data to determine the long-term
				  geometric mean color or alkalinity, the Department shall place the lake on the
				  Verified List for exceedances of the narrative nutrient criterion in paragraph
				   62-302.530(47)(b),
				  F.A.C., if the annual geometric mean chlorophyll
a
exceeds the
				  applicable criterion for a colored lake in sub-subparagraph
				   62-302.531(2)(b) 
				  1.b., F.A.C., more than once in a three year period in the last 7.5
				  years.
(5) If the waterbody was
				  listed on the Study List for an adverse trend in nutrient response variables
				  pursuant to paragraph
				   62-303.390(2)(a),
				  F.A.C., the Department shall analyze the potential risk of nonattainment of the
				  narrative nutrient criteria in paragraph
				   62-302.530(47)(b),
				  F.A.C. This analysis shall take into consideration the current concentrations
				  of nutrient response variables, the slope of the trend, and the potential
				  sources of nutrients (natural and anthropogenic). If there is a reasonable
				  expectation that the waterbody will become impaired within 5 years, the
				  Department shall place the waterbody on the Verified List to develop a TMDL
				  that establishes a numeric interpretation pursuant to paragraph
				   62-302.531(2)(a),
				  F.A.C.
(6) The thresholds for
				  impairment due to nutrients in paragraph
				   62-302.531(2)(c) 
				  and subsections  62-303.351(4) 
				  and  62-303.353(2),
				  F.A.C., are not required to be used during development of wasteload allocations
				  or TMDLs where a site-specific interpretation of the narrative nutrient
				  criterion in paragraph
				   62-302.530(47)(b),
				  F.A.C., is established.
(7) When
				  assessing waters for nutrient impairment, the Department shall evaluate whether
				  the data were collected under extreme climatic conditions, such as floods,
				  droughts, and hurricanes. If the needed supporting information is provided to
				  the Department, the Department shall also evaluate whether the data were
				  collected under conditions that are representative of the type of waterbody
				  used to derive the applicable criteria, and whether the samples are biased
				  towards specific non-representative flow conditions. When assessing estuary
				  specific numeric interpretations of the narrative nutrient criterion in rule
				   62-302.532, F.A.C., the
				  Department shall also evaluate whether the current ambient monitoring network
				  is representative of the network that was the basis for the numeric
				  interpretation of the narrative nutrient criterion in Rule
				   62-302.532, F.A.C. The
				  Department will consider this information when developing the final Verified
				  List and shall not list waters as impaired based solely on extreme climatic
				  conditions, non-representative data, or changes in the monitoring
				  network.
Rulemaking Authority
						403.061,
						403.067 FS. Law Implemented
						403.062,
						403.067
						FS.
New 6-10-02, Amended 12-11-06, 7-2-12, 8-1-13,
						2-17-16.