Minimum flows and levels

Upper Ocklawaha River Basin lakes peer review

The St. Johns River Water Management District is seeking public input as part of its work to develop minimum flows and levels (MFLs) for the Upper Ocklawaha River Basin (UORB), including lakes Apopka, Beauclair, Dora, Eustis, Harris and Griffin, in Lake, Marion and Orange counties.

MFLs are the minimum water flows and/or levels adopted by the district’s Governing Board as necessary to prevent significant harm to the water resources or ecology of an area resulting from permitted water withdrawals.

An important part of setting MFLs is the development and calibration of surface water models. Surface water models are computer programs that use continuous rainfall and other meteorologic records to simulate water levels and/or flows within water bodies. The use of models allows the district to evaluate whether MFLs are met under different water management scenarios, such as potential future water withdrawals that may lower lake water levels.

The district has initiated the formal peer review of the UORB hydrologic model (HSPF — Hydrological Simulation Program—Fortran). The models, supporting documents, and peer review panel and stakeholder review comments regarding these models and documents can be accessed using the links in the box on this page.

The district invited stakeholders to participate in an UORB Lakes Model Peer Review Teleconference during which staff reviewed the UORB Lakes calibration model sensitivity analysis. The teleconference was held May 12.

Map of the Upper Ocklawaha River Basin