Challenge. Establish minimum flows and levels (MFLs) to identify the limit at which further withdrawals would be significantly harmful to the water resources or ecology of the area.

Solution. The MFL development process is multi-faceted and involves data collection and exploratory data analysis, statistical and/or hydrologic modeling, and evaluation of water resource values and ecological parameters. In support of the MFL programs of four Florida water management districts (Southwest Florida Water Management District [SWFWMD], St. Johns River Water Management District [SJRWMD], Suwanee River Water Management District [SRWMD], and Northwest Florida Water Management District [NWFWMD]), INTERA has helped establish MFLs for dozens of priority waterbodies that include rivers, estuaries, lakes, and springs. The focus of our MFL support has been on applying both analytical methods (statistical) and numerical models. Our MFL experience includes: modeling un-gauged flows for the Alafia River Watershed, Little Manatee River Watershed, and Cow Pen Slough; developing HEC-RAS steady-state and transient models to assist the SRWMD in establishing MFLs for the Suwannee River system and its tributaries (i.e., Santa Fe River, Ichetucknee River, Withlacoochee River, Alapaha River); HEC-RAS modeling for Horse Creek, Charlie Creek, Alafia River North and South Prongs, and Gum Springs for the SWFWMD; statistical analyses to support MFLs as part of the Central Florida Water Initiative; development and application of artificial neural networks (ANNs) to evaluate salinity in the Manatee River; and development of hydrologic relationships for key ecological features on the Santa Fe River. Because of our MFL expertise, INTERA has also provided independent peer review of scientific and technical data, methodologies, assumptions, and conclusions related to MFLs developed by other consultants. This includes review of MFLs for over a dozen waterbodies such as Blue Springs, the Silver River, the Upper Ocklawaha River, Lake Tarhoe, Prevatt Lake, Johns Lake, Lake Jessup, Lake Hiawassee, Lake Avalon, Sylvan Lake, the Lower Santa Fe River and the Etonia chain of lakes.