Watershed Evaluation and Total Maximum Daily Loads (TMDL) Section

News and Announcements

New!

The Florida Department of Environmental Protection will host a public meeting on Tuesday, March 4, 2025, beginning at 10 a.m. EST, to review the draft nutrient total maximum daily loads (TMDLs) for the lakes identified below in the Middle St. Johns River and Kissimmee River Basins. TMDLs for lakes in the Middle St. Johns Basin will be adopted in Rule 62-304.505, Florida Administrative Code (F.A.C), and TMDLs for lakes in the Kissimmee River Basin will be adopted in Rule 62-304.515, F.A.C. These nutrient TMDLs, if adopted, will constitute a site-specific numeric interpretation of the narrative nutrient criterion set forth in paragraph 62-302.530(48)(b), F.A.C., and replace the otherwise applicable numeric nutrient criteria in subsection 62-302.531(2), F.A.C., for these waterbodies.

What is a TMDL? 

A TMDL is a scientific determination of the maximum amount of a given pollutant that a surface water can absorb and still meet the water quality standards that protect human health and aquatic life. Waterbodies that do not meet water quality standards are identified as "impaired" for the particular pollutants of concern - nutrients, bacteria, mercury, etc. - and TMDLs must be developed, adopted and implemented to reduce those pollutants and clean up the waterbody.

The threshold limits on pollutants in surface waters - Florida's surface water quality standards on which TMDLs are based - are set forth primarily in rule 62-302, Florida Administrative Code, and the associated table of water quality criteria.

What are the basic steps in the TMDL program? How does it work?

1. Assess the quality of surface waters-are they meeting water quality standards? (Surface Water Quality Standards - Chapter 62-302).
2. Determine which waters are impaired-that is, which ones are not meeting water quality standards for a particular pollutant or pollutants. (Impaired Waters Rule (IWR) - Chapter 62-303).
3. Establish and adopt, by rule, a TMDL for each impaired water for the pollutants of concern-the ones causing the water quality problems. (TMDLs - Chapter 62-304).
4. Develop, with extensive local stakeholder input, Basin Management Action Plans (BMAPs) that:

• Implement the strategies and actions in the BMAP.
• Measure the effectiveness of the BMAP, both continuously at the local level and through a formal re-evaluation every five years.
• Adapt-change the plan and change the actions if things aren't working.
• Reassess the quality of surface waters continuously.

We are working on a more comprehensive approach to protecting Florida water quality involving basin-wide assessments and the application of a full range of regulatory and non-regulatory strategies to reduce pollution. The Total Maximum Daily Load is the heart of this comprehensive approach.

Locations of the DEP's Adopted TMDLs

• For locations of TMDLs in Florida, view our interactive TMDL map and status of TMDLs in Florida documents (Rule 62-304, F.A.C.).
• Please help us improve our service by providing feedback on what you think of our adopted TMDL document, whether it is useful and how could we make it better. Please contact Kevin O'Donnell, 850-245-8469.