Damaging releases from Lake Okeechobee to the Caloosahatchee and St. Lucie estuaries will restart Friday after the Army Corps of Engineers said it has no other alternative to ensure the integrity of the aging Herbert Hoover Dike.
Col. Jason Kirk, the Corps’ Jacksonville District commander, acknowledged the discharges could worsen harmful algae blooms in Treasure Coast and western waterways, but said he fears a “catastrophic” loss if the swollen lake were to breach the dike following heavy rainfall from a tropical system.
“It would not just be damage to homes and business that affect 37,000 people,” Kirk said. “The water that would sit on that land for months would be devastating.”
The decision to restart releases after a temporary respite was expected, but it comes as toxicity levels in the algae are testing in amounts that one expert called “dangerous.”
An algae sample taken July 5 at the St. Lucie Lock near Phipps Park in Stuart was returned Tuesday with toxin levels of 154 micrograms per liter — 15 times higher than what the World Health Organization considers low risk. Earlier samples from the Caloosahatchee River in Lee County were even higher at 463 micrograms per liter and 308 micrograms per liter.
Anything over 20 micrograms per liter is considered a “high risk for acute health effects.”
“Yes, that is dangerous,” said Kathleen Rein, a professor in Florida International University’s Department of Chemistry. “People should definitely not be swimming in that. Stay away from it. Don’t let your pets drink the water.”
Rein said acute liver failure is a worst-case scenario from swimming in or drinking toxic algae-laced water. But rashes, respiratory problems and nausea also are linked to toxic algae.
The Corps began releasing water from Lake Okeechobee on June 1 following Florida’s rainiest May on record. To protect Glades-area communities from flooding if the dike were to fail, the Corps likes to keep the lake level between 12.5 and 15.5 feet above sea level. During the rainy season — when one tropical system could raise the lake three feet in a month — the lower end of the scale is preferred.
On Thursday, Lake Okeechobee stood at 14.48 feet above sea level. That’s two feet higher than it was at this time in 2017, and the third highest level for the same time period in the past 11 years.
The highest the lake has been was 18.7 feet in 1947.
The Corps built the Herbert Hoover Dike after hurricanes in 1926 and 1928 killed thousands of people when the lake overflowed, flooding hundreds of square miles. Although built to the highest engineering standards at that time, the dike was molded from gravel, rock, limestone and sand, which allow water to seep through and cause erosion if the lake gets too high.
“How long does it take to get rid of two feet of water?” asked Brandon Tucker, a member of the South Florida Water Management District’s governing board, during a Thursday meeting. “We would need a significant amount of time if we had a storm approaching and sometimes we have less than a week’s notice.”
A rough estimate by Corps spokesman John Campbell is that it would take at least three weeks to lower the lake a foot if discharges to the estuaries were at full throttle.
“We all know it takes six times longer to drain the lake then it does to fill it up,” said district board member Jim Moran.
But discharging lake water, which is high in nutrients from agricultural and residential runoff from the north, lowers salinity levels in the estuaries. That promotes algae growth in estuaries already flushed fresh by May rainfall.
Former Sewall’s Point Mayor Jacqui Thurlow-Lippisch said she’s seen improvement on the St. Lucie after a 14-day pause in Lake O releases. Releases to the Caloosahatchee were put on hold Monday.
“For whatever reason, when they open those gates up, you see the river shift,” she said. “I knew it was coming. It’s such a shame.”
Kirk pointed out that the vast majority of the water entering the Caloosahatchee and St. Lucie is local basin runoff that is not coming from Lake Okeechobee. About 27 percent of water going into the Caloosahatchee is lake water, while about 15 percent of St. Lucie’s inflows have been from the lake, Kirk said.
To mitigate damage to the estuaries, the Corps will release lake water in pulses that will allow sea water to reach deeper into the waterways.
“It is really affecting our lives and livelihoods and the livability of the area,” Thurlow-Lippisch said. “These algae blooms aren’t going away. This is the new normal for now.”