Total Maximum Daily Loads (TMDL) - Nutrients

What is a TMDL?

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. Water bodies 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 for those pollutants to reduce pollutants and clean up the water body.

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

The Divisions 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 (TMDL) is the heart of this comprehensive approach.