WEST PALM BEACH — An internal message from the U.S. Army Corps of Engineers that was distributed via email to Palm Beach County Commissioners on July 17, has some officials concerned that the corps will make changes to the schedule for releases from Lake Okeechobee even before the new Lake Okeechobee System Operating Manual is complete.
Since 2008, the corps has used the Lake Okeechobee Regulation Schedule (LORS’08) as the guideline for lake releases. LORS’08 attempts to maintain between a high level of 15.5 feet (above sea level) and a low of 12.5 feet.
Concerns about the safety of the Herbert Hoover Dike, the earthen berm that surrounds the big lake, is one of the reasons the upper limit was set at 15.5 feet. Repairs to the dike are scheduled to be complete in 2022. Earlier this year, the corps began the process of holding public hearings.
Levels above 15.5 feet also damage the marshes around the edges of the lake, which filter water and provide habitat for fish and wildlife.
The published schedule called for the draft LOSOM report to be available for public comment in April or May 2022, with the new manual ready to implement by September 2022.
Earlier this year, following public calls by Congressman Brian Mast and at the urging of Gov. Ron DeSantis, the corps released more water during the dry season, bringing the lake down to 10.5 feet before the beginning of the rainy season on June 1. Rep. Mast has promoted this idea in order to provide more capacity in the big lake for flow from the north during the wet season.
At the March 22 meeting of the County Coalition for the Responsible Management of Lake Okeechobee, St. Lucie and Caloosahatchee Estuaries and the Lake Worth Lagoon, Lt. Col. Jennifer Reynolds said corps was not ordered to bring the Big O down to 10.5 feet, but was using the flexibility available under the Lake Okeechobee Regulation Schedule to try to lower the lake this year only, to help regrow the vegetation that was lost due to Hurricane Irma. The science does not support lowering the lake to 10.5 feet every year, she added.
The message shared to the Palm Beach County commissioners was from Melissa Nasuti of the U.S. Army Corps of Engineers, dated July 10, with the subject “LORS 2008 Deviation.” The message was copied to other corps officials.
In the message, Ms. Nasuti states that the corps is preparing National Environmental Policy Act (NEPA) documentation for a planned deviation from LORS’08 “in anticipation of and following freshwater harmful algae blooms (HABs) with the goal of reducing the risk to public health and safety associated with HABs.”
This planned deviation will alter the timing and volume of the lake releases to the Water Conservation Areas (WCAs), east (to the St. Lucie) and/or west (to the Caloosahatchee) “to allow for greater flexibility with water management decisions when HABs are present in Lake Okeechobee, the St. Lucie or the Caloosahatchee estuaries or the system of canals that connect them.”
As was done this year, the deviation would increase lake releases during the dry season.
Ms. Nasuti states the flow target for the Caloosahatchee would be between 450 cubic feet per second and 2,800 cubic feet per second, measured at the Franklin Lock. Flows below 450 cfs allow saltwater intrusion into the upper estuary. Flows above 2,800 cfs are harmful to the sea grasses and oysters in the lower estuaries.
“Within the St. Lucie Estuary, targets are based on freshwater discharges at the S-80 (the St. Lucie Lock), S-48, S-49 and Gordy road structures where the target frequency of mean biweekly flows should be maintained between 350 and 2,000 cfs. Based on the salinity tolerances of oysters, flows less than 350 cfs result in higher salinities at which oysters are susceptible to increased predation and disease. Flows in the 350-2000 cfs range produce tolerable salinities,” the message states.
The message does not mention flows at the Moore Haven lock, where water enters the Caloosahatchee River from the lake, or the Port Mayaca Lock, where the water enters the St. Lucie Canal from the lake. Local basin runoff can take up some or even all of the targets set for the Franklin and St. Lucie locks.
The planned deviation would be implemented as soon as possible and would be in effect for a minimum duration of one year, the message states. The deviation may extend until LORS’08 is replaced by LOSOM.