Corps to continue releases from Lake O to coastal estuaries

Posted 3/11/21

With Lake Okeechobee at 15.1 feet, the U.S. Army Corps of Engineers will continue releases

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Corps to continue releases from Lake O to coastal estuaries


JACKSONVILLE – With Lake Okeechobee at 15.1 feet, the U.S. Army Corps of Engineers will continue releases east to the St. Lucie Canal at an average of 500 cubic feet per second and to the west to the Caloosahatchee River at 2,000 cfs.

Some of the water included in the measured flow may be local basin runoff. Releases to the St. Lucie River are measured at the St. Lucie Lock, which is 23.9 miles from Port Mayca, where the lake water enters the St. Lucie Canal. Releases to the Caloosahatchee are measured at the Franklin Lock, which is 43.4 miles from Moore Haven, where the Lake Okeechobee water enters the Caloosahatchee River.

On Thursday, Lake Okeechobee was 15.1 feet above sea level. In a media conference call, Col. Andrew Kelly, commander of the Jacksonville District of the U.S. Army Corps of Engineers, said that’s a little over 0.2 feet lower than last week. The lake is 2.68 feet higher than one year ago.

The current release schedule began on March 6 and will continue indefinitely.

“We’re still looking at a lake that is higher than we want,” said Kelly. The lake level may be “potentially higher than we want come the hurricane season start,” he explained.

The releases are part of a plan to put the system in the best possible location prior to hurricane season, Kelly said. Releasing some water now, when there is no algae on the lake, may mean less water will be released during the summer, when the potential for algae is much higher.

“This is the time of the year where lake releases arguably do the least amount of harm to the estuaries,” said Kelly.

“We’re being aggressive, but also mindful that we don’t go too far,” he continued. “We’re working with stakeholders and scientists to make sure we don’t go too hard too fast.”

While there is concern about the high lake level, conditions on the Big O are good, he explained. “It’s a great year around Lake Okeechobee for snail kite nesting. It’s a great year for wading birds.”

In addition to the releases east and west, the corps is sending about 800 cfs south. Some of that water goes to the water users, and is used to irrigate crops in the Everglades Agricultural Area. Some goes to the stormwater treatment areas (STA) for eventual flow under the Tamiami Trail to Everglades National Park. Kelly said they are “sending as much water south as we can.”

Flow south has been limited this dry season by flooding south of the lake. An extremely wet fall, including Tropical Storm Eta, dumped heavy rainfall south of Lake Okeechobee and left water backed up in the water conservation areas (WCAs) north of the Tamiami Trail. Flow under the trail is limited not only by the capacity of the water control structures but also by requirements to prevent high water levels in the nesting area of a subpopulation of the endangered Cape Sable Seaside Sparrow and by the problems of seepage in the 8.5 square mile development just east of Everglades National Park (also called Las Palmas).

Kelly said as the dryness continues and the area south of the lake starts to dry out, they hope to be able to increase flow south. The drier it is, the more water can be used for irrigation, he said. The drier it is, the more water the STAs can handle. We will leverage that tool to the best of our ability,” he said. “We will keep an eye on the estuaries to make sure the things we are doing aren’t disrupting too much in a negative way.”

The releases east and west are just part of the puzzle. The 2,000 cfs released west and 500 cfs released east totals about 9.45 billion gallons a week. With 11 weeks left in the dry season, that would equal about 8.6 inches on Lake O. Combined with evapotranspiration from the water surface, percolation of water into the aquifer and flow south, Kelly said the models show the lake will be around 13.5 feet at the start of the wet season. He cautioned the models are based on current weather predictions, which could change. If the weather is much drier than expected, the lake could go down to 12.5 feet by June 1. If the weather is wetter than anticipated, it could be above 14 feet at the start of the wet season.

“We have to be careful and observant and reassess on a weekly basis,” said Kelly.

“We’re seeing the effects of our efforts now,” he said. While the 500 cfs sent east may seem like an insignificant amount of water compared to the billions of gallons in one inch of water on the lake, “I have to look at it in total,” he explained. He said they want to buy as much space as possible in the lake before the wet season starts to avoid the need for harmful wet season freshwater releases to the coastal estuaries.

“Right now we’re looking at this being a long term thing,” he said. “We’re being very measured, very deliberate and very mindful.

“This is the time of year there isn’t really any algae present on Lake Okeechobee,” he said. “Absolutely algae has influences over releases. When we start seeing it, it certainly impacts our release decisions to the estuaries. If history holds true, it’s a little while before algae starts showing up on the lake.”

Kelly said work continues on the Lake Okeechobee System Operating Manual (LOSOM) which will go into effect in 2022 when the repairs to the Herbert Hoover Dike are complete. The LOSOM studies have included thousands of computer modeling runs to determine the best, balanced approach to managing the lake levels. He said the round 1 model results will be released on Friday.

Lake Okeechobee, releases, algae, estuary, St. Lucie, Caloosahatchee