Sylvan Lake Minimum Flows and Levels

Sylvan Lake is located in Seminole County, Florida, approximately 5 miles west of the city of Sanford. This approximately 186-acre lake was added to the St. Johns River Water Management District’s MFLs Priority List and Schedule, as part of an effort to implement a regional network of MFLs sites within central Florida. Sylvan Lake is both ecologically and recreationally valuable, containing extensive wetland habitat as well as an adjacent extensively used public park. Sylvan Lake is a popular outdoor destination, offering opportunities for fishing, kayaking, and wildlife viewing.

The district is currently completing a reevaluation of the adopted MFLs, to ensure the continued protection of Sylvan Lake’s environmental and recreational resources. The current plan is to submit a Notice of Proposed Rule (NPR) for Sylvan Lake by the end of 2020. When draft MFLs documents are completed, they will be available on this page.

The district’s MFLs approach involves two separate but interrelated components: 1) MFLs Determination; and 2) MFLs Assessment. The first involves determining a minimum hydrologic regime necessary to protect relevant water resource values. The second involves comparing this MFLs condition to a current-pumping condition to determine the current status of the MFLs. The current-pumping condition could be above or below the MFLs condition. The overall process involves environmental assessment, hydrologic modeling, independent scientific peer review, and rulemaking.

Lily pads spread across Sylvan Lake
Lilies spread across Sylvan Lake
American flag over Sylvan Lake
Map of Sylvan Lake, Seminole County

The district typically engages in voluntary peer review of all MFLs on its Priority List. Because Lake Sylvan is within the Central Florida Water Initiative (CFWI) area, the district will follow the CFWI MFLs peer review process. This includes stakeholder involvement in the selection of the peer review panel as well as stakeholder involvement in public workshops for the review of the models, hydrological analyses and environmental analyses that are used to determine and evaluate proposed MFLs within the CFWI.

As with other CFWI MFLs, the Sylvan Lake MFLs peer review is divided into two phases. First, the surface water model, including calibration, and long-term simulations, will be reviewed by one or more independent technical experts in the field of hydrologic modeling. The second phase of the peer review process will involve an evaluation of recommended minimum lake levels, including the environmental criteria used for MFLs determination and the hydrologic analyses used for MFLs assessment. One or more environmental firms will be selected for review of the MFLs determination and assessment. The model peer reviewer(s) and MFLs determination/assessment peer reviewer(s) will constitute the peer review panel for the Sylvan Lake MFLs.

Peer Review Panel Selection 

  • CFWI MFL peer review process
  • Selection screening
  • Draft peer review scope of work (SOW)
  • Public comments and responses regarding peer review panel selection

District staff updated a Hydrological Simulation Program Fortran (HSPF) model developed for Sylvan Lake by CDM Smith. This model will be used to support the development and assessment of MFLs at Sylvan Lake. The intent of the district is to ensure that this HSPF model is developed and implemented based on sound science and modeling principles. Peer review of model application will focus on the appropriateness of the model, input data and calibration procedures, and the proposed uses of model results.

Peer review tasks

The peer review process has been divided into tasks and subtasks, each with deliverables and/or meetings, allowing for stakeholder participation throughout the process.

Task A. Project kick-off meeting and site visit

  • Meeting date – TBD

Task B. Peer review Sylvan Lake HSPF model and documentation report

B.1 Review models and documentation

  • To be uploaded

B.2 Peer review public workshop

  • Meeting date – TBD

B.3 Draft peer review technical memorandum

  • To be completed

B.4 Peer review public teleconference

  • Teleconference date – TBD

B.5 Final peer review technical memorandum

  • To be completed

District responses to model peer review

  • To be completed

Final Sylvan Lake MFLs modeling report

  • To be completed

Final Sylvan Lake MFLs model files

  • To be completed