Minimum Flows & Minimum Water Levels
One of the ways in which the South Florida Water Management District is working to protect and conserve Florida's water resources is through the minimum flows and minimum water levels (MFLs) program. Establishing MFLs is an important step in the District's work of planning for adequate water supplies while also protecting water resources from significant harm. In South Florida, minimum levels have been established for lakes, wetlands and aquifers. Minimum flows have been set for rivers, streams and estuaries.
MFLs are defined as the minimum flows or minimum water levels, adopted by the District Governing Board pursuant to Sections 373.042 and 373.0421, Florida Statutes, at which further withdrawals would be significantly harmful to the water resources or ecology of the area. Establishing MFLs for all of South Florida is an ongoing effort. The Priority Water Body List and Schedule for developing or re-evaluating MFLs is submitted annually to the Florida Department of Environmental Protection. The District publishes a draft technical document summarizing the methods, models and data that provide the scientific basis of an MFL, which may be subject to periodic re-evaluation and/or scientific peer review by an independent panel of experts. The MFL development process also includes public rule development meetings that allow interested stakeholders opportunities to provide comments on the draft technical document and proposed draft rule language prior to Governing Board approval and adoption. The MFL is then implemented through the District's consumptive use permitting and water supply planning programs.
Florida Statewide Annual Report
The Florida Department of Environmental Protection has published the Florida Statewide Annual Report on Total Maximum Daily Loads, Basin Management Action Plans, Minimum Flows or Minimum Water Levels and Recovery or Prevention Strategies on its website pursuant to section 403.0675, F.S. This report, published by July 1 each year beginning in 2018, includes the status of protection and restoration actions through total maximum daily loads, basin management action plans, minimum flows or minimum water levels and recovery or prevention strategies. Visit www.floridadep.gov/star for more information.
Caloosahatchee MFL Rule Development
The public hearing and rule adoption originally planned for August 8, 2019 has been moved to the October 10, 2019 Governing Board meeting.
On September 13, 2018, the District Governing Board passed a motion to adopt amendments to Subsection 40E-8.221, F.A.C. to revise the minimum flow and level criteria for the Caloosahatchee River. The amended rule is provided below.
- Amended Rule – Chapter 40E-8.221, F.A.C., Minimum Flows and Levels (MFLs): Surface Waters – Sept. 13, 2018 [PDF]
Additional analyses were conducted in October 2018 in response to public comments received on the amended MFL criteria. A summary of these additional analyses is available below with other relevant documents. Public comments received to date on the project and further project documentation is provided on the District Web Board in the SFWMD MFL and Water Reservation Categories/MFL Re-evaluation for the Caloosahatchee River Estuary forum.
- Additional Science Document – October 2018
- FINAL Technical Document to Support Re-evaluation of the Minimum Flow Criteria for the Caloosahatchee River Estuary – Jan. 30, 2018 [PDF]
- Errata Sheet for FINAL Technical Document to Support Re-evaluation of the Minimum Flow Criteria for the Caloosahatchee River Estuary – Jan. 30, 2018 [PDF]
- 2017 Final Peer Review Report – Oct. 26, 2017 [PDF]
- Presentations: Rule Development Workshop #1 – Feb. 15, 2018 [PDF]
- Presentation: Caloosahatchee River MFL West Coast Technical Meeting – May 7, 2018 [PDF]
- Presentations: Rule Development Workshop #2 – June 1, 2018 [PDF]
- Presentation: SFWMD Governing Board Rule Adoption Hearing – Sept. 13, 2018 [PDF]
For additional information, please contact Toni Edwards, SFWMD Senior Scientist, at email@example.com.
Frequently Asked Questions
MFLs are established to protect water resources from significant harm resulting from permitted water withdrawals. Establishing MFLs is a requirement of the state Legislature under Subsection 373.042(2), Florida Statutes (F.S.). In addition, establishing MFLs is required by the state Comprehensive Plan, the water resources implementation rule (formerly state water policy) and a 1996 Governor's executive order for priority water bodies.
MFLs identify a range of water levels and/or flows above which water could be permitted for consumptive use. The MFLs program supports the District's regional water supply planning process (section 373.0361, F.S.); permitting criteria for the consumptive use permitting program (Chapter 40C-2, F.A.C.); and the environmental resource permitting (ERP) program.
In addition, MFLs protect nonconsumptive uses of water. Nonconsumptive uses include quantities of water necessary for navigation and recreation and for fish and wildlife habitat.
Florida law states that the District's Governing Board "shall use the best information and methods available to establish limits which prevent significant harm to the water resources or ecology." MFLs are determined based on evaluations of topography, soils and vegetation data collected within plant communities and other pertinent information associated with the water resource.
MFLs take into account the ability of wetlands and aquatic communities to adjust to changes in hydrologic conditions. MFLs allow for an acceptable level of change to occur. When use of water resources shifts the hydrologic conditions below levels defined by MFLs, significant ecological harm can occur.
MFLs are adopted as water management district rules (Chapter 40E-8, Florida Administrative Code) by the governing boards of the water management districts. This is a public process that involves documenting the scientific and technical information that supports the MFL, peer review of that information and public workshops. The MFL is then reviewed by the Florida Department of Environmental Protection, then adopted by the District and published in the Florida Administrative Weekly. MFLs are to be reviewed periodically and revised as necessary per Subsection 373.0421(3), F.S.
MFLs apply to decisions affecting permit applications, declarations of water shortages and assessments of water supply sources. Computer simulation models for surface and groundwaters are used to evaluate the effects of existing and/or proposed consumptive uses and the likelihood they might cause significant harm. The District's Governing Board is required to develop recovery or prevention strategies in those cases where a water body currently does not or will not meet an established MFL. Water uses cannot be permitted that cause any MFL to be violated. Specific recovery or prevention strategies are found in the regional water supply plans and in the District's MFL technical publications.
Related Documents – MFL Rule Development Supporting Documentation
Lake Okeechobee, Northern Biscayne Aquifer and the Everglades
- Minimum Flows and Levels for Lake Okeechobee, the Everglades, and the Biscayne Aquifer, February 2000 Draft [PDF]
- Appendices to Minimum Flows and Levels for Lake Okeechobee, the Everglades, and the Biscayne Aquifer, February 2000 Draft [PDF]
- Final MFL Rule [PDF]
Lower West Coast Aquifer
- Proposed Minimum Water Level Criteria for the Lower West Coast Aquifer System within the SFWMD, Sept. 5, 2000 Draft [PDF]
- Final MFL Rule [PDF]
St. Lucie River & Estuary
- Technical Documentation to Support Development of Minimum Flows for the St. Lucie River and Estuary [PDF]
- Technical Documentation to Support Development of Minimum Flows for the St. Lucie River and Estuary Appendices [PDF]
- Final MFL Rule [PDF]
Caloosahatchee River & Estuary
- Technical Documentation to Support Development of Minimum Flows and Levels for the Caloosahatchee River and Estuary Draft 2003 Status Update Report [PDF]
- Technical Documentation to Support Development of Minimum Flows for the Caloosahatchee River and Estuary Appendices [PDF]
- Technical Documentation to Support Development of Minimum Flows and Levels for the Caloosahatchee River and Estuary (September 2000 Draft) [PDF]
- Final Peer Review Report of Minimum Flows for the Caloosahatchee River and Estuary Appendices (September 2000) [PDF]
- Final MFL Rule [PDF]
Northwest Fork of the Loxahatchee River
- A Review and Evaluation of the Minimum Flow and Level for Northeastern Florida Bay – Final Report (June 2014) [PDF]
- Technical Documentation to Support Development of Minimum Flows and Levels for Florida Bay [PDF]
- Technical Documentation to Support Development of Minimum Flows and Levels for Florida Bay Appendices [PDF]
- Scientific Panel Report [PDF]
- Final MFL Rule [PDF]