Lake Okeechobee releases to Caloosahatchee increase this week

Jacksonville District
Published Nov. 5, 2021

The U.S. Army Corps of Engineers (USACE) Jacksonville District will execute two changes to Lake Okeechobee Operations in the next week, both effecting the Caloosahatchee River Estuary.

The initial change is a regulatory release increase starting Nov. 6 from the current 1,000 cubic feet per second (cfs) to the Caloosahatchee Estuary to 2,000 cfs to support estuary ecology, followed by a one-day deviation that begins Nov. 9 as part of an ongoing sediment study by the South Florida Water Management District (SFWMD) and the U.S. Geological Survey (USGS). There are no plans to release lake water from the St. Lucie Lock and Dam (S-80) at this point. 

The regulatory change that begins Nov. 6 will be measured at the W.P. Franklin Lock and Dam (S-79). Lake flows will be reduced and may stop completely based on local basin runoff. Flows from S-79 could exceed the target without lake contributions if the region receives heavy rainfall. 

“Right now, the lake is in a good position, and after talking with stakeholders, we believe these releases will help maintain salinity levels in the estuary as dry season rain patterns reduce fresh water flows,” said Lt. Col. Todd Polk, Jacksonville District Deputy Commander for South Florida. “These flows also have the potential to kick start dry season lake recession that will help get the lake back into its ecological band.”

The deviation to the Lake Okeechobee Regulation Schedule that begins Nov. 9 is part of the ongoing study by the South Florida Water Management District (SFWMD) and U.S. Geological Survey (USGS) to find ways to predict sediment and nutrients transportation from the lake to the estuaries. 

The deviation will allow up to 6,000 cubic feet per second (cfs) flow for short periods of time for up to 8 hours at the Julian Keen Jr. Lock and Dam (S-77). USACE executed a similar deviation in April to support the same study. 

While the deviation allows for up 6,000 cfs releases in short durations, it is expected that the daily average flows will be closer to 1,600 cfs at S-77. Downstream flows at W.P. Franklin Lock and Dam (S-79) are expected to be elevated due to these releases for Nov. 9. The maximum effect of these releases on Lake Okeechobee stage is less than ¼ inch. 

USACE is not aware of any FDEP test results of algae found at or near S-77 or along the C-43 in the recent weeks, but any more sampling and observations of algae will be taken into consideration.

Jim Yocum

Release no. 21-084