Development and Improvement of Habitat Suitability Criteria for Instream Habitat Assessments Conducted in Support of Environmental Flows in Florida

ABSTRACT Florida's regulatory framework requires the establishment of minimum flows to protect aquatic ecosystems and water resources from significant harm. One of the primary methods used to evaluate significant harm is assessment of instream habitat, which relies on Habitat Suitability Criteria (HSC) curves that relate flow regimes and habitat availability for aquatic species. This study aimed to improve the scientific foundation and applicability of HSC curves used in Florida by compiling, reviewing, updating, and developing new curves tailored to the State's unique hydrography. The project involved a comprehensive review of existing HSC curves, modifications based on empirical data from Florida's river monitoring programs, and the development of new curves through field studies and expert consensus. The resulting HSC library increases the ecological relevance, transparency, and legal defensibility of instream flow assessments in Florida. The HSC library and supporting guidance document provide water managers with a tool to support sustainable water resource planning and rulemaking across the diverse freshwater systems in the state.