Trace levels of algae toxins found in St. Lucie Canal

Posted 2/28/23

The U.S. Army Corps of Engineers has stopped releases from Lake Okeechobee to the St. Lucie River ...

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Trace levels of algae toxins found in St. Lucie Canal


PORT MAYACA -- The U.S. Army Corps of Engineers, Jacksonville District is closely monitoring, in coordination with the South Florida Water Management District (SFWMD), and Florida Department of Environmental Protection (FDEP), blue-green algae conditions at Port Mayaca Lock and Dam (S-308) after receiving aerial imagery showing a thin ribbon of algal mass moving towards the gate on Feb. 27.

On Feb. 22, Florida Department of Environmental Protection sampled water at Port Mayaca. No toxins were detected lakeside. Trace levels of toxins were detected in the St. Lucie Canal, at 0.62 micrograms per liter. The Environmental Protection Agency considers levels below 1 microgram per liter safe for drinking water. Microcystin levels below 8 micrograms per liter are considered safe for human recreational contact (swimming).

During the USACE morning assessment on Feb. 28, blue-green algae was not visibly present to USACE operators from the surface. After receiving the imagery, USACE immediately shut down S-308 (the St. Lucie Lock) to further assess and monitor conditions.

SFWMD crews assessed the bloom on Feb. 28 and did not detect any visible blue green algae. However, SFWMD crews will sample the area. The samples will be analyzed by the FDEP in Tallahassee. Lock operators conduct visual inspections of the lake and structures for potential algae blooms multiple times daily.

While not an authorized project purpose, water quality is a critical consideration in operational decision making. USACE works closely with the state agencies responsible for water quality, consider it in NEPA analyses for studies and projects, and when possible, avoid making releases during times when harmful algal blooms are present on the lake. USACE continues to provide information to the public about the presence of algal blooms near our structures, facilities, and waterways we manage.

The overall dry-season strategy has not changed, but S-308 remains closed as USACE assesses conditions. They will continue to utilize our make-up releases as a water management tool within the Lake Okeechobee Regulation Schedule 2008 (LORS08) to release the water they have banked up this winter. As they move further into the dry season, they will continue releases using the available volume of banked water at beneficial levels. They are committed to transparency throughout the implementation of make-up releases.