During the 2018-2019 dry season, the U.S. Army Corps of Engineers released freshwater from Lake Okeechobee east to the St. Lucie River and west to the Caloosahatchee, lowering the level of Lake Okeechobee to less than 11 feet by the end of the dry season. At the time, corps officials told Lake Okeechobee area officials this was done to benefit the lake’s ecology and to allow the regrowth of vegetation in the lake’s marshes which had been devastated by Hurricane Irma and years of high water levels. The low lake level in the summer of 2019 did help the lake’s aquatic vegetation recover. But the reason for the draw-down is not that simple.
A letter from Maj. Gen. Scott A. Spellmon, deputy commanding general for Civil and Emergency Operations, U. S. Army Corps of Engineers, to Gov. Ron DeSantis shows the corps was being pressured by the Florida governor to lower the lake to 10.5 feet before the start of the wet season to reduce the chance of wet season releases to the St. Lucie and Caloosahatchee estuaries.
In the Feb. 11, 2019, letter to Gov. DeSantis, Maj. Gen. Spellmon wrote: “During our meeting on 13 December, you asked the U.S. Army Corps of Engineers to pursue an elevation of 10.5 feet at Lake Okeechobee going into this year’s rainy season with an objective of minimizing or eliminating discharges later in the year. This letter serves to confirm our commitment to taking action. I have issued the enclosed directive to the commander of our Jacksonville District to lower water levels this season to the extent possible consistent with our current LORS (Lake Okeechobee Regulation Schedule) and the National Environmental Policy Act. As you discussed with the Jacksonville District commander last week, our team, along with regional experts and affected stakeholders, is evaluating aggressive actions to responsibly lower Lake Okeechobee levels now to reduce the risk of undesirable high volume releases during the rainy season.”
A memorandum signed by Maj. Gen. Spellmon, also dated Feb. 11, 2019, states: “In order to reduce further risk to the public, the Jacksonville District will lower Lake Okeechobee levels as much as possible within the Operational Band of the Lake Okeechobee Regulation Schedule prior to the state of the Hurricane Season 2019. Increased dry season flows to the south, east and west of the lake are necessary now to reduce the risk of high volume, potentially damaging releases during the wet season.”
On Feb. 22, 2019, a press release from the U.S. Army Corps of Engineers Jacksonville District announced : “The corps will use Additional Operational Flexibility as defined by the 2008 Lake Okeechobee Regulation Schedule to increase flows for the next three weeks. Starting Saturday, Feb. 23, and continuing for the next 21 days, the corps will release water to the Caloosahatchee estuary at an average rate of 1,800 cubic feet per second from the W.P. Franklin Lock & Dam, and to the St. Lucie estuary from the St. Lucie Lock & Dam (S-80) at an average rate of 500 cubic feet per second. Additional runoff from rain in the Caloosahatchee and St. Lucie basins could occasionally result in flows that exceed one or both targets.”
During the dry season, the Caloosahatchee River needs freshwater flow from Lake Okeechobee to prevent saltwater intrusion. Before the river was connected to the lake via a man-made canal, the Caloosahatchee received flow from the lake only during the wet season, when water flowed through marshes from the Big O to a series of smaller lakes and eventually to the Caloosahatchee River. The connection to the lake to provide a liquid highway for pioneer transportation, followed by dredging to straighten the river to make river traffic easier and projects to deepen a channel for flood control, all changed the basin’s hydrology. The South Florida Water Management District has set the minimum freshwater flow target at 457 cubic feet per second, measured at the Franklin Lock. If there is not enough rain in the Caloosahatchee basin to maintain that flow, water is released from Lake Okeechobee at Moore Haven, which is about 43 miles from the Franklin Lock.
The corps started releasing extra water from the lake during the 2018-2019 dry season in October 2018.
• On Oct. 4, 2018, the corps started releasing water to the Calooosahatchee at 1,000 cfs, more than double the minimum level of 457 cfs required to maintain salinity levels in the estuaries. No water was released the St. Lucie at that time,
• On Jan. 25, 2019, that target was reset to 700 cfs. At that time, the lake level was 12.32 feet.
• On Jan. 31, 2019, the corps resumed releases of 1,000 cfs to the Caloosahatchee.
• From Feb. 23, 2019, through March 15, 2019, the corps released water to the Caloosahatchee estuary at an average rate of 1,800 cubic feet per second from the W.P. Franklin Lock & Dam, and to the St. Lucie estuary from the St. Lucie Lock & Dam (S-80) at an average rate of 500 cubic feet per second.
The corps is currently working on the Lake Okeechobee Systems Operating Manual (LOSOM) which will go into effect when the repairs to the Herbert Hoover Dike are complete in 2022. The May LOSOM Project Delivery Team (PDT) meeting was canceled. The next LOSOM PDT meeting is tentatively set for June 25. Public comments may be made in regard to LOSOM online at www.saj.usace.army.mil/LOSOM.