Total Maximum Daily Loads (TMDLs)

The United States Environmental Protection Agency has stated that 25 years ago approximately one third of the nation's waters were safe for swimming and fishing. Over the last 25 years however, the quality of waters has improved due to communities implementing programs for public health and pollution control. The nation's waters are now approximately two-thirds safe for swimming and fishing. However, according to the 1996 National Water Quality Inventory, approximately 40 percent of the surveyed water bodies in the area are still impaired by pollution.

The Total Maximum Daily Load (TMDL) Program is a water quality program administered by the Florida Department of Environmental Protection (DEP) under the Florida Watershed Act (Section 403.067 F.S.) The DEP works with stakeholders and municipalities to determine how to reduce targeted pollutant loadings to restore the legally designated uses of the polluted waters.


A TMDL is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards. The water quality standards are set by the Florida Department of Environmental Protection. The FDEP identifies the uses for each waterbody; for example, drinking water supply, swimming or fishing. A TMDL is the sum of the allowable loads of a single pollutant from all contributing point and nonpoint sources. The calculation must include a margin of safety to ensure that the waterbody can be used for the purposes the state has designated. The calculation must also account for seasonal variation in water quality. The Clean Water Act, section 303, establishes the water quality standards and TMDL programs.


The issues that the TMDL Program addresses are not new. Non-point sources such as stormwater and agricultural runoff, and point sources such as industrial wastewater outfalls have created water quality concerns in Florida for decades and have been addressed in various ways.

Under the Florida Watershed Restoration Act, TMDLs must be developed for all waters that do not meet their designated uses due to human impact and consequently are defined as impaired. The primary sources of human impacts are urban runoff, agricultural runoff and industrial and municipal wastewater treatment plants.


There are five phases to implementation of the TMDL program:

  • Phase 1: Preliminary evaluation of water quality
  • Phase 2: Strategic monitoring and assessment to verify water quality impairments
  • Phase 3: Development and adoption of the TMDLs for water verified as impaired
  • Phase 4: Development of a Basin Management Action Plan (B-MAP) to achieve TMDLs
  • Phase 5: Implementation of the plan and monitoring of results


The City of Daytona Beach will be required to identify and partner with surrounding communities to reduce the pollutant load on the impaired waters identified by the FDEP. Impaired water bodies will then be targeted for reduction in pollutant loading by the development of a Basin Management Action Plan. The B-MAP outlines the responsibilities and pollutant load reductions required from each community in a particular drainage basin. For more information and a list of the impaired waters that are under evaluation please see the Water Quality Status Report.