PALATKA, Fla., March 14, 2017 — In the second of a series of informational presentations to the Governing Board and the public, St. Johns River Water Management District staff Tuesday worked to demystify one of the most complex tools used by the agency to strike the necessary balance between nature’s needs and people’s needs for water — the Minimum Flows and Levels (MFLs) program. MFLs define the limits at which further water withdrawals would be significantly harmful to the water resources or ecology of an area.
“The district has been setting MFLs for nearly 30 years, and it continues to be among the most challenging and complicated work we do,” said St. Johns River Water Management District Executive Director Dr. Ann Shortelle. “This is difficult science — there is no single level or flow that can protect all water bodies. We are constantly reviewing established MFLs and working to improve our data to ensure these MFLs are appropriate.”
Since the program began in 1990, MFLs have been established for 101 lakes, six rivers, seven wetlands and 10 springs. This year, MFLs will be set for five springs, while MFLs established for three lakes are scheduled for re-evaluation.
In Tuesday’s presentation, staff explained the overarching question MFLs seek to address is whether a water body’s current flow or water level is sufficient to protect environmental values, such as water quality, habitat and fish passage, recreation, freshwater storage and supply and more.
“Using available scientific data and literature, we are able to link ecological response to changes in hydrologic event frequency and then to sustainable yield,” said Mike Register, director of the Division of Water Supply Planning and Assessment. “The result is a measurable, defensible amount of water available for public uses that also is protective of the environment.”
Because flows and levels of rivers, lakes and springs are dynamic and vary naturally, the district seeks to capture and protect high, low and average conditions by setting multiple MFLs for each priority water body. Additionally, plant and animal communities and species are adapted to high and low flow/stage events. The district uses the most constraining MFL for determining available water.
When necessary, prevention and recovery strategies are developed and implemented to ensure MFLs will not be violated by future water withdrawals (prevention), or will be recovered to meet their MFLs (recovery) if a violation caused by withdrawals has already occurred.
Prevention and recovery strategies call for water withdrawals to be maintained at or below sustainable limits, or for impacts from water withdrawals to be mitigated through water supply development projects — such as reclaimed water, aquifer recharge and water supply projects — and conservation and regulatory measures.
MFLs are set by rule, and public workshops offer the opportunity for stakeholder comment. Visit the district online at http://www.sjrwmd.com/minimumflowsandlevels/ for information about the MFLs program, rules in development or public meetings.