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Corps steps down harmful Lake Okeechobee releases

By JAMES EVANS - | Dec 15, 2020

In a much-anticipated decision on Dec. 3, the U.S. Army Corps of Engineers announced that it would begin cutting back freshwater releases to the Caloosahatchee from Lake Okeechobee.

This was not only welcome news for the Caloosahatchee estuary, which has received ecologically damaging flows for the past three months, it is also good news for the coastal communities impacted by the releases.

The Corps’ plan will cut back flows from the lake over a two-week period. Beginning Dec. 5, average flows were reduced from 4,000 cubic feet per second (cfs) measured at the Moore Haven Lock (S-77) to 3,000 cfs. Beginning Dec. 12, discharges will be further reduced to 2,000 cfs measured at the Franklin Lock (S-79). Once flows drop below 2,100 cfs, they are considered to be in “optimal range” according to ecological targets established for the estuary.

During the past three months, conditions throughout the mid and lower Caloosahatchee estuary have been poor for oysters and seagrasses, putting stress on the organisms that form the basis of the estuarine food web.

These organisms are resilient and can recover if provided suitable conditions for a period long enough to support recovery. However, if high flows continue, or if flows are cut back too much during the dry season, these organisms can lose their resiliency and ability to recover.


The reduction in flows comes at a critical time as we are beginning to see red tide (Karenia brevis) showing up in the Gulf along the southwest coast. Recent samplings by the Sanibel-Captiva Conservation Foundation Marine Lab and the Florida Fish and Wildlife Conservation Commission red tide status maps indicated low levels (>10,000-100,000 cells/L) of Karenia brevis, the organism responsible for Florida red tides, along Sarasota County and parts of Lee, and medium (100,000-1,000,000 cells/L) to high levels (>1,000,000 cells/L) along Sanibel and Captiva.

Karenia brevis is known to use many sources of nutrients, and scientists are concerned that excess nutrients from lake releases and runoff from the Caloosahatchee watershed could feed red tide as it moves near shore along the coast.

Like our estuarine organisms, our coastal communities have been severely impacted by the poor quality of our coastal waters. At times, the dark-colored freshwater plume has extended five to seven miles offshore into the Gulf of Mexico, impacting local businesses and the tourism industry that rely on our beaches and coastal waters.

These current impacts come just as we are beginning to recover from the devastating red tide bloom of 2018. The 2018 bloom resulted in more than 850,000 pounds of dead marine life being removed from Sanibel’s beaches and more than $47 million in economic impacts to local businesses.

Analogous to the estuary, our communities are also resilient and can recover if provided suitable conditions. Our communities desperately need a recovery period, and we hope that water managers will equitably balance all of the needs of the natural systems and communities that rely on Lake Okeechobee.

James Evans is environmental policy director for the Sanibel-Captiva Conservation Foundation. Founded in 1967, the SCCF is dedicated to the conservation of coastal habitats and aquatic resources on Sanibel and Captiva and in the surrounding watershed. For more information, visit www.sccf.org.