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TMDL Development Cycle


The Watershed Management Program (WMP) is based on a five-phase cycle that rotates through Florida's basins every five years. Objectives and specific tasks in each phase of the cycle are as follows:

The development cycle outlined below will take place within the context of chapter 99-223, Laws of Florida, which details a specific process for listing impaired waters, determining which waters will be subjected to Total Maximum Daily Loads calculations, adopting by rule those TMDL calculations and associated allocations of pollutant loadings, and implementing the management strategies designed to reduce the loadings and enable the water body to meet water quality standards.

Phase 1: Initial Basin Assessment

Objectives: Establish the general ecological health of the basin, identify waterbodies requiring restoration, protection, and/or TMDL development, identify sources of pollution, develop a coordinated monitoring plan, and develop consensus-based water resource protection and restoration goals.

Specific tasks include:

  • identify and coordinate with local, state, and federal stakeholders (public and private) to assist in data collection, basin assessment, and development of a coordinated plan of action for completing the assessment
  • characterize each basin, including climate, geology, hydrology (surface and ground water), water budget, biology (bioassessments), land use, population, and known sources of pollution (point and nonpoint)
  • inventory and evaluate existing data (within and outside DEP) to characterize basin conditions; use STORET data and 305(b) methodology to generally assess major water bodies and overall basin water quality, including ground water basin evaluation and biology (HUC and watershed level assessment); and evaluate other existing data in the context of identified problem watersheds
  • provide a detailed description of water resource issues for the basin; identify candidate waters for TMDL development, restoration and/or preservation; characterize point sources and nonpoint sources of pollution; identify specific parameters of concern (biological/chemical), including summary statistics and temporal variability, as available; and characterize watershed vulnerability
  • summarize existing and planned management activities (local, state, and federal) to address identified water resource issues, concentrating on water quality management
  • conduct field reconnaissance to identify potential sources of pollution and ground truth land use data
  • identify information needs, develop monitoring goals (establish questions to be answered), identify monitoring methodologies and resources required, and develop plan of study for coordinated monitoring within the basin
    • the monitoring plan will address design (location of sampling stations, indicators to be measured, and frequency of sampling), data management, and reporting
  • summarize water quality management goals for the basin and identify management activities that should be initiated in the short term, produce and distribute basin assessment report for public review, comment, and consensus building among all stakeholders
  • assess effectiveness of point source controls, Best Management Practices (BMPs), and TMDLs

Phase 2: Coordinated Monitoring
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Objectives: Supplement existing data to further characterize basin conditions, investigate areas with identified or potential water quality problems, evaluate the effectiveness of management actions, and collect data for TMDL development.

Specific tasks include:

  • conduct monitoring as established in a plan of study and as otherwise may be required in waters requiring TMDL development, restoration or preservation
    • monitoring will include intensive surveys in 303(d) listed waters, bioreconnaissance studies (biorecons), VISA evaluations (intensive ground water surveys), and parameter specific studies, and will focus on both point and nonpoint sources of pollution

Phase 3: Data Analysis and TMDL Development
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Objectives: Document the water quality data collected in phase 2, noting any changes in the conclusions of the initial basin assessment; provide a more detailed assessment of major pollutant sources, including the quantification of nonpoint source loadings; and conduct and document TMDLs, as needed.

Specific tasks include:

  • summarize available flow data, providing statistics on worst case conditions and noting differences in flow from long term averages
  • summarize water quality data from targeted monitoring stations, noting seasonal variation, differences in water quality within the basin, compliance with water quality criteria, and overall ranking of water quality
  • summarize results of intensive surveys, noting any spatial and temporal trends and compliance with water quality criteria
  • summarize results of biorecons, perhaps in the form of Ecosummaries
  • summarize results and conclusions of any special studies
  • inventory and quantify major pollutant sources, including determination of nonpoint source pollutant loadings of key parameters
  • conduct modeling to determine assimilative capacity, establish TMDLs, and evaluate main management alternatives

Phase 4: Basin Management Plan Development
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Objectives: Work with local stakeholders to develop a Basin Management Plan to specify how established goals will be achieved by recommending management activities, establishing who is responsible for implementation, establishing a schedule for implementation, and noting how the effectiveness of the plan will be assessed. While the plan will focus on implementation of TMDLs developed in the basin, it will also address more general watershed goals.

Specific tasks include:

  • coordinate with DEP staff in other program areas along with local stakeholders to draft a Basin Management Plan
  • identify appropriate regulatory and voluntary programs that can address water quality problems and implement TMDLs
  • conduct at least one public workshop to discuss the draft Basin Management Plan
  • adopt the Basin Management Plan

Phase 5: Begin Implementation of Basin Management Plan
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Objectives: Begin implementation of the Basin Management Plan and associated water resource protection and restoration efforts, including development and implementation of BMPs, habitat protection and restoration activities, environmental infrastructure improvements, and issuance of permits.

Specific tasks include:

  • renew or issue wastewater permits in the basin with new effluent limits, as required
  • develop and implement appropriate BMPs (agricultural/stormwater)
  • initiate rulemaking or legislative action as may be required

This five-phase cycle is iterative. One of the key components of the basin management approach is that the effectiveness of management activities will be monitored in successive cycles. Monitoring conducted in Phase 2 of the subsequent cycles will be targeted at evaluating whether water quality objectives are being met and waters are no longer impaired.

Linkage to TMDL implementation

Total Maximum Daily Loads are key components of the Watershed Management Program. The five-year cycle provides the structure for focusing resources on specific basins, identifying impaired waters, conducting targeted monitoring that will provide the data needed for model calibration and verification, and developing TMDLs for impaired waters. Basin Management Plans are a critical product of the Watershed Management Program because they provide the roadmap for implementation of the TMDLs, and will serve as basin-specific, consensus driven implementation plans.

For more information on the development of water quality restoration goals (TMDLs), send e-mail to Erin Rasnake.

Water Quality Evaluation & TMDL Program
2600 Blair Stone Road - Mail Station 3555
 Tallahassee, FL, 32399-2400
Phone: (850) 245-8338

For information on TMDL grants, Section 319 (nonpoint source) grants, and other financial assistance for water infrastructure projects or implementation of urban or agricultural best management practices, please see our financial assistance webpage to determine what opportunities might be right for your project.

Last updated: June 30, 2016

  2600 Blair Stone Road M.S. 3500   Tallahassee, Florida 32399   850-245-8336 (phone) / 850-245-8356 (fax) 
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