Lake Okeechobee discharges begin to St. Lucie River, increase to Caloosahatchee River

Excess Lake Okeechobee water will be discharged to the St. Lucie River and increased to the Caloosahatchee River starting Friday morning, officials announced Thursday.

Discharges to the St. Lucie will average about 1.2 billion gallons a day as measured at the St. Lucie Lock and Dam west of Stuart. Discharges west to the Caloosahatchee will ramp up to nearly 2.6 billion gallons a day.

It will be the first discharges to the St. Lucie since 192 billion gallons poured through the St. Lucie Lock and Dam from Sept. 6 to Dec. 28 — the ninth worst event since 1969.

The move comes after more than two weeks of daily rains swelled the lake more than a foot in 18 days, to an elevation a foot and a half higher than the Army Corps of Engineers wants it to be this time of year.

The lake rose from a May 13 low of 12 feet, 9 ⅞ inches to just over 14 feet Thursday. The Corps wants the lake to be 12 feet, 6 inches each June 1, so it can hold rain from the summer wet season without the danger of the Herbert Hoover Dike breaching.

"We have to be prepared for additional water that could result from a tropical system," Col. Jason T. Kirk, Corps commander for Florida, said in a prepared statement. "The lake today is above the stage when Irma struck in September, which eventually caused the water level to exceed 17 feet. A similar storm could take the lake to higher levels."

Wet forecast

The total discharge amount and duration will depend on how long the rain lasts.

"There's a good chance of rain every afternoon for the next week or so," Jessie Smith, a meteorologist at the National Weather Service in Melbourne, said of the forecast for the area from Orlando south to Okeechobee, the watershed for Lake O.

The weather service hasn't declared an official start to the summer rainy season, Smith said, "but whether it's official or not, it's going to be raining every day."

More: Learn more about Lake O discharges to the St. Lucie River

The discharge rate of 1.2 billion gallons a day is the maximum allowed under the Corps' guidelines on when and how much lake water it's allowed to send to the St. Lucie River.

"We started the way we did and the amount we did because of the rate the lake is rising," said John H. Campbell, a Corps spokesman. "We wanted to get on top of the situation so we might not have to release even more water later on."

The Corps doesn't expect the discharges to lower the lake, Campbell said, "but hopefully we can slow the rise in the lake."

The actual amount released from the lake may be limited by the fact that the C-44 Canal, which connects the lake to the river, is only half a foot lower than the lake.

Local runoff

That means much of the water flowing through the St. Lucie Lock and Dam and into the river will be rainfall runoff from fields in western Martin County that drain into the C-44 Canal.

Since May 14, more than 18 billion gallons of that water has flowed into the St. Lucie, turning the normally brackish river estuary "completely fresh," said Mark Perry, executive director of the Florida Oceanographic Society in Stuart.

Adding Lake O water increases the threat to the river's oysters and sea grass beds, which require salty water to survive.

Lake O discharges in 2016 brought blue-green algae from a massive bloom in the lake to the St. Lucie. There, the algae was fed by more nutrients from other canals and exploded into a bloom that covered much of the river around Stuart.

There's no algae bloom in the lake now, but conditions are ideal for one to form, said Jim Sullivan, a research professor and interim executive director at Florida Atlantic University's Harbor Branch Oceanographic Institute in Fort Pierce.

"I wouldn't be surprised if there's a big bloom in the lake this summer," Sullivan said Wednesday as he unveiled a NASA-built device Harbor Branch will install in the lake to monitor algae levels.

More: NASA, Harbor Branch partner on SeaPRISM to track Lake Okeechobee algae

St. Lucie discharges