Army Corps may delay Lake Okeechobee discharges because of king tides, algae blooms

Tyler Treadway   | Treasure Coast Newspapers The Army Corps of Engineers might not be able to start

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Tyler Treadway   | Treasure Coast Newspapers

The Army Corps of Engineers might not be able to start Lake Okeechobee discharges to the St. Lucie River later this week, even if the agency wants to.

Col. Andrew Kelly, the Corps commander for Florida, last week warned discharges could start soon, but that was before this week's flooding in the river's south fork, brought on by so-called "king tides."

Also, the day after Kelly's warning, a satellite took photos of blue-green algae in the lake near the Port Mayaca Lock and Dam, where lake water would be discharged.

Kelly is expected to announce the Corps's decision Thursday.

More: Corps says to get ready for Lake O discharges to St. Lucie River

Here's a look at factors that could delay the discharges:

South Fork flooding

A combination of high seasonal tides, often called "king tides," and a heavy swell along Florida's East Coast caused by Hurricane Teddy far out in the Atlantic Ocean, have resulted in flooding in low-lying areas of Martin County.

Flooding has been particularly bad along the South Fork of the St. Lucie River just downstream of the St. Lucie Lock and Dam, where the Lake O discharges would enter the river, including Old Palm City and the St. Lucie Settlement area southwest of Stuart.

"We've got pretty significant water in roadways," said Martin County Public Works Director Jim Gorton, "but no water in homes has been identified."

More: Corps cut discharges in 2017 when king tides caused flooding

The king tides peaked Tuesday and "conditions should begin improving by Thursday, but tides will be about 1 foot to 1½ foot higher than normal until the end of the week," said Krizia Negron, a meteorologist a the National Weather Service in Melbourne.

Corps spokesperson Jim Yocum said conditions along the South Fork "are always considered when we are executing release decisions."

The Lake Okeechobee Regulation Schedule that guides the Corps' lake operations, states water shouldn't be released through the St. Lucie Lock and Dam when the water elevation on the downstream side is 3 feet or higher because of "the potential for flooding."

As of Wednesday morning, the water elevation downstream of the dam was 2 feet, 3¾ inches; Tuesday morning it was 3 feet, ¾ inch.

"Conditions are getting better," Gorton said, "but until the downstream system recovers significantly, we'd prefer the Corps not do any discharges. I hope they delay as long as possible. If they delayed all season, I'd be tickled to death."


Video: How a drop of water at Disney can pollute the St. Lucie River

Here's why that Lake O reservoir is necessary. DACIA JOHNSON/TCPALM

Blue-green algae

A satellite image taken Saturday showed a dense bloom on the eastern side of the lake close to Port Mayaca.

In a letter to the Corps Tuesday, U.S Rep. Brian Mast, R-Palm City, cited the threat of blue-green algae as a reason to hold off on discharges.

More: Mast urges Corps to delay discharges

More: Read Congressman Mast's letter to Colonel Kelly

Sightings of algae at Port Mayaca "show there is active risk of algal blooms being discharged from Lake Okeechobee to the estuaries," Mast wrote. "This risk is intolerable. ... Under no circumstances should the federal government be choosing to poison Americans, and that is what high-volume, toxic algae-laden discharges amounts to."

The threat of sending toxic algae to the estuary "will have an influence" on the discharge decision, Kelly said Friday. "But if it comes to the point that we need to move water out of the lake because of the risk of (a dike breach), we'll move water out of the lake."

Lake O 'in a good spot'

At an elevation of 15 feet, 2⅝ inches Wednesday morning, Lake O "is at an almost perfect level," said Paul Gray, who studies the lake for Audubon Florida. "Maybe an inch or 2 high, but that's OK."

Lake O needs to reach 15 feet, Gray said, to put water on about 100,000 acres of marsh on the lake's west side. Without that water, land-based plants take over where water-based plants ought to be, disrupting the lake's ecosystem.

The higher level also is good for nesting snail kites and wading birds.

More: Stakeholders debate best levels for Lake Okeechobee

"The lake didn't reach 15 feet last year, so now we're in recovery mode," Gray said.

One caveat: "If a storm comes in and raises the lake 2 or 3 feet, that's not good," Gray said. "But there aren't any storms on the horizon, and we're getting close to the end of the rainy season. It's a risk, but not a big risk."

Limited effect

If the discharges begin, the amount of Lake O water sent to the St. Lucie River will be limited because so much water is coming into the river already.

Guidelines call for a target flow of 630 million gallons of water a day through the St. Lucie Lock and Dam. On Tuesday, 251.3 million gallons of water, all rainwater runoff from western Martin County, flowed through the dam.

That would limit discharges of Lake O water to 378.7 million gallons a day.

The target flow from Lake O to the Caloosahatchee River would be 1.6 billion gallons a day. That estuary is already getting a daily average of 2.6 billion gallons from rainwater runoff, so discharging lake water would have to wait until the flow drops by at least 1 billion gallons a day.

"Even if you did the full releases the regulations call for, you'll lower the lake by about an inch in a week," Gray said. "If a storm raises the lake by a foot or 2, that inch isn't a lot of protection. The end of the wet season isn't the time to try to lower the lake."

Tyler Treadway is an environment reporter who specializes in issues facing the Indian River Lagoon. Support his work on  Contact him at 772-221-4219 and
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