Minimum Flows and Levels (MFLs)

Florida law requires establishment of minimum flows and levels of water bodies to prevent significant harm associated with water withdrawals.

Program overview

Florida law (Chapter 373.042, Florida Statutes) requires the state water management districts or the Department of Environmental Protection to establish minimum flows and levels (MFLs) for aquifers, surface watercourses, and other surface water bodies to identify the limit at which further withdrawals would be significantly harmful to the water resources or ecology of the area. Rivers, streams, estuaries and springs require minimum flows, while minimum levels are developed for lakes, wetlands and aquifers. Minimum flows and levels are adopted into Southwest Florida Water Management District (District) rules (Chapter 40D-8, Florida Administrative Code) and used in the District’s water use permitting program to ensure that withdrawals do not cause significant harm to water resources or the environment.

Water bodies with adopted MFLs, and those the District is currently or planning to work on, are identified in the District’s Minimum Flows and Levels Priority List and Schedule. The priority list and schedule, which is updated annually, is based upon the importance of the listed waters to the state or region and the existence of potential for adverse impacts associated with water use.


The District collects and analyzes a variety of data for each water body to help define significant harm and for the application of methods used to develop minimum flow or minimum water level recommendations. An essential component of the District’s MFL establishment process includes the voluntary use of peer review, during which independent scientists review and comment on proposed MFLs and the methods used for their derivation. The establishment process also includes an opportunity for public review, allowing all interested stakeholders to provide comments before the flows or levels are incorporated into District rules. The intent of the process is to be inclusive while developing scientifically defensible MFLs that will help protect our water resources and allow sustainable withdrawals to meet human needs. If actual flows or levels are, or are expected to be, below an established MFL within the next twenty years, the District develops and implements a recovery or prevention strategy (Chapter 40D-80 of the Florida Administrative Code), in accordance with state law (Section 373.0421 of the Florida Statutes).

Want to know more about minimum flows and levels, visit the Frequently Asked Questions »