Middle St. Johns - Florida Department of Environmental Protection

Water Quality Assessment Report: Middle St. Johns
181
Chapter 5: TMDL Development, Allocation,
Implementation, and Monitoring Priorities
Prioritization of Listed Waters
Following the identification of impaired waters on the 303(d) list, the
Florida Department of Environmental Protection (Department) determines
priorities for developing Total Maximum Daily Loads (TMDL) in Phase 3
of the watershed management cycle. When TMDLs are established,
general allocations of pollutant load reductions are identified, at least to the
level of point and nonpoint source categories.
Because TMDLs cannot be developed for all listed waters during a
single watershed management cycle, waterbodies will be prioritized using
the criteria in the Impaired Surface Waters Rule (IWR) (Rule 62-303.500,
Florida Administrative Code [F.A.C.]). The rule states that when establishing
the TMDL development schedule for waters on the Verified List,
the Department will prioritize impaired waterbody segments according to
the severity of the impairment and each waterbody’s designated uses, taking
into account the most serious water quality problems, most valuable and
threatened resources, and risk to human health and aquatic life.
Under the IWR, the determination of high-, low-, and mediumpriority
waters is based on the following criteria.
High-priority waters:
• Waterbody segments where the impairment poses a threat to potable
water supplies or human health;
• Waterbody segments where the impairment is due to a pollutant
regulated by the Clean Water Act and the pollutant has contributed
to the decline or extirpation of a federally listed threatened or endangered
species, as indicated in the Federal Register listing the species;
or
• Waterbody segments verified as impaired that are included on the
U.S. Environmental Protection Agency’s (EPA) 1998 303(d) list as
high priority.
Low-priority waters:
• Waterbody segments that are listed before 2010 because of fish
consumption advisories for mercury (due to the current insufficient
understanding of how mercury cycles in the environment);