Lake level deviation is ‘all about algae’

Posted 9/25/19

When it comes to the level of Lake Okeechobee, there’s a lot of confusion.

In a Sept. 20 media conference call, Col. Andrew Kelly of the U.S. Army Corps of Engineers tried to straighten out some …

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Lake level deviation is ‘all about algae’


When it comes to the level of Lake Okeechobee, there’s a lot of confusion.

In a Sept. 20 media conference call, Col. Andrew Kelly of the U.S. Army Corps of Engineers tried to straighten out some of the misconceptions about the Lake Okeechobee Regulation Schedule (LORS), LORS operational flexibility, LORS deviations and the Lake Okeechobee System Operating Manual (LOSOM).

LORS ’08
The current Lake Okeechobee Regulation Schedule is sometimes referred to as LORS ’08, because the current schedule was adopted in 2008. Since the 1990s, corps reports had warned that the Herbert Hoover Dike, an earthen berm which surrounds the second largest freshwater lake in the confines of the continental United States, was at risk of failure should a hurricane come across the state when the lake level was already above 16 feet. Computer models indicated that as the lake level rises, so does the chance of a breach. Should the berm fail during a hurricane, other water control structures south of the Big O — including the East Coast Protection Levy — are also at risk of failure.

The models predicted such a dike failure would endanger thousands of human lives and could result in billions of dollars of property damage as well as an ecological catastrophe for much of South Florida.

The levy failures in New Orleans after Hurricane Katrina brought more attention to the damn safety reports which put the Herbert Hoover Dike at the top of the “most at risk” list. A 2006 South Florida Water Management District report concluded the dike was in “grave and imminent” danger of failure. In 2008, the new schedule was adopted to keep the lake below 15.5 feet above sea level.

While LORS ’08 was developed as a temporary measure to protect public safety while dike is repaired, environmentalists maintain the 12 or 12.5 feet to 15.5 feet is also the best range for the lake’s own ecology. The lake’s natural system depends on seasonal highs and lows. Low water periods allow the marshes around the edge of the lake to recover and new vegetation to grow, providing habitat for fish and wildlife. Lake levels above 16 feet drown out the marshes.

Operational flexibility
“Over the winter, we made an effort to reduce the lake level, predominantly for the lake ecology,” said Col. Kelly. He said the lake had suffered damages from Hurricane Irma and from several consecutive years of high water levels, and the corps tried to lower the lake level to give the lake’s submerged aquatic vegetation a chance to recover.

He said they used the operational flexibility in LORS to release more water to the Caloosahatchee during the dry season. For the most part these releases were within the freshwater flow most beneficial to the Caloosahatchee estuaries. Without freshwater flow from the lake during the dry season, the Caloosahatchee can suffer from salt water intrusion. For a six-week period in February and March, flows to the Caloosahatchee were increased and pulse releases were conducted to the St. Lucie canal.

Col. Kelly said that based on the water conditions and the weather forecasts, they decided to use the operational flexibility in LORS to release some water at a time the schedule did not call for releases.

This was a one-time opportunity, he stressed. This is not something the corps plans to or wants to do every year.

“It’s healthy for the lake to bring it down every once in a while,” he said.

LORS deviations
Col. Kelly said most recently, the corps considered deviations to the lake schedule. While operational flexibility is built into LORS, deviations are not part of the schedule. Deviations are “all about algae,” explained the colonel. A deviation means the corps may not follow LORS “if and when there is potential for algae from the lake to be pushed into the estuaries.”

If there is bloom potential and the lake is low, water will not be released to the estuaries, he said.

If there is no algae bloom and the lake is rising, the corps might release water to the estuaries.

“It’s all about algae. It’s not about lake level,” said Col. Kelly.

He said the deviations are “a reaction to what we saw last year.”

The corps is currently working on the Lake Okeechobee System Operating Manual (LOSOM) which will go into effect in 2022, when repairs on the dike are projected to be complete. LOSOM will take into consideration the additional storage in the system that will also be complete at that time, included the C-43 reservoir near the Caloosahatchee River and the C-44 reservoir near the St. Lucie Canal. Water from the C-43 reservoir will store excess water during the wet season and that water can be released to help maintain the optimal salinity levels in the Caloosahatchee River in the dry season. The C-44 reservoir will capture and treat some basin runoff, reducing the freshwater flow to the St. Lucie in the wet season. In addition, LOSOM will include water storage north of the lake including the changes planned for the Kissimmee Chain of Lakes when the partial restoration of the Kissimmee River is completed. LOSOM will not include use of the Everglades Agricultural Area reservoir, because that project will not be completed by 2022. The earliest projected completion date for the EAA reservoir is 2028. According to Col. Kelly, LOSOM will likely be revised in about 10 years.

LOSOM PDT meeting
The LOSOM Project Delivery Team will meet via a webinar on Thursday, Sept. 26, from 1 to 4:30 p.m. To join the webinar (please be sure to put your phone on mute and do not put your phone on hold during the webinar) go online to

USA Toll-Free:  877-336-1831

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The PDT meetings provide representatives from different government agencies an opportunity to provide input, comments and concerns as the LOSOM plan is developed. The PDT members include only the federal officials and elected officers of state, local or tribal governments or their designated employees with authority to act on their behalf acting in their official capacities. Members of the public are welcome to attend the government agency PDT meeting and provide comment during designated periods.

No releases east or west
On Friday, Col. Kelly announced that no water will be released from the lake to the coastal estuaries this week as the lake hovers just below 14 feet. He said releases south are primarily for water supply.

“We are going to maintain our decision of no water releases to the estuaries, and continue to send water south for water supply,” said Col. Kelly. “We were actually able to send an average of 3,655 cubic feet per second south this past week.”

“Lake levels have stabilized since the beginning of September, and the forecast is for drier conditions, but we’re not out of the woods yet,” said Kelly. “September is the peak of hurricane season in the Atlantic and tropical activity remains high. We will continue to monitor conditions closely and adjust releases as necessary.”

While flow from the lake is being released to the Caloosahatchee estuary, a minimal flow averaging around 60 cubic feet per second has been released through the Moore Haven lock into the Caloosahatchee River to maintain the water level needed for navigation in the Lake Okeechobee Waterway. Col. Kelly explained that when there is not enough local basin runoff to maintain the water level needed for navigation, some water from the lake is released through the lock at Moore Haven while the next lock (the S-78 water control structure at Ortona) is closed.

At current lake levels, the 2008 Lake Okeechobee Regulation Schedule (LORS) allows the release of a total of up to 650 cubic feet per second (cfs) from the lake to the estuaries. Collaborative efforts by the South Florida Water Management District and the corps to provide additional capacity in the system south of the lake have allowed the corps to maximize releases south.