Lake Okeechobee fell below 11 feet above sea level on Monday.
Most of the decline in the lake level is from evaporation into the air and percolation into the aquifer.
Since May 18, the U.S. Army Corps of Engineers has been releasing water from Lake Okeechobee at the rate of 800 cubic feet per second at Moore Haven into the Caloosahatchee River, to protect the river from saltwater intrusion. However, these releases account for a minimal difference in the lake level. One inch of water on the big lake is the equivalent of 12 billion gallons of water. At a flow of 800 cfs per day, it would take 23 days to drop Lake Okeechobee by 1 inch. In addition, the corps measures the flow at the Franklin Lock, which is 43.4 miles from Moore Haven, so part of the flow through that structure is from local basin runoff.
While the lower lake levels may be beneficial to regrowth of the lake’s natural aquatic vegetation, which was damaged by three years of high water levels, extremely low water levels can be hazardous for boaters, especially for those unfamiliar with the underwater topography of the big lake.
The corps advises boaters to monitor water levels prior to taking a boat out on the lake.
The last time Lake Okeechobee dropped below 11 feet was in 2017. That year, the lake was below 11 feet for four days. The lowest lake level in 2017 was 10.93 feet above sea level on June 2. Later that summer, the lake level rose rapidly due to Hurricane Irma.
According to the South Florida Water Management District website, when Lake Okeechobee drops below 12 feet above sea level, SFWMD closes the locks on the north shore for safety reasons. Injury and damage to the boats and/or to the lock could occur if boats attempt to pass through the locks when the water level is too low. The lock closures are also necessary to boat traffic to prevent damage to the manatee protection devices inside the lock chamber, to maintain water levels in adjacent canals and to protect groundwater availability.
• The S-131 at Lakeport in Glades County is closed when the lake falls below 12 feet. It will reopen when the lake rises above 12.5 feet.
• The S-135 at J&S Fish Camp in Martin County is closed when the lake falls below 12 feet. It will reopen when the lake rises above 12.5 feet.
• The G-36 at Henry Creek in Okeechobee County is closed when the lake falls below 12 feet. It will reopen when the lake rises above 12.5 feet.
• The S-193 at Taylor Creek is closed when the water levels fall below 11 feet. It will reopen when the lake level is above 11 feet and rising.
• The S-127 at Buckhead Ridge in Glades County is closed when the lake falls below 12 feet. It will reopen when the lake rises above 12.5 feet.
With the locks on the north end of Lake Okeechobee closed to boat traffic, boaters on the north side of the lake can still access the lake by using the boat ramps inside the dike at the Clif Betts Jr. Lakeside Recreation Area (aka Lock 7) or Okee-Tantie, or boat ramps on the Kissimmee River such as the boat ramps at the C. Scott Driver facility.
Why is water released?
During the dry season the U.S. Army Corps of Engineers releases water from Lake Okeechobee to the Caloosahatchee River to prevent saltwater intrusion and maintain optimal salinity levels in the Caloosahatchee estuary.
This year, the corps has also been urged to lower the lake during the dry season, to ensure more storage capacity for wet season flow in order to prevent the potential need for wet season releases to the coastal estuaries, by Gov. Ron DeSantis and Congressman Brian Mast.
The South Florida Water Management District has guaranteed the Caloosahatchee a minimum 400 cfs dry season flow; Lee County officials have asked for 700-800 cfs and, in a lawsuit filed last year, stated that the optimum flow at the Franklin Lock is 1,000 cfs. According to biologists, the optimum flow ranges from 450 to 1,000 cfs, depending on the season. Different marine plants and animals have varying salinity requirements.
The Franklin Lock is 43.4 miles from the Moore Haven lock, so the water flowing through the Franklin Lock is a mixture of lake water and basin runoff that flows directly into the river.
Through most of the dry season, the corps has given the Caloosahatchee the 1,000 cfs, requested by Lee County officials to help the estuary’s ecology recover from the effects of damage from the storms in recent years.
During part of February and the month of March, the flow was increased slightly in an effort to lower Lake Okeechobee. During the period, the flow was higher than the desired 1,000 cfs, salinity levels in the estuary were monitored to ensure the extra freshwater did not harm the estuary’s ecology.
• From April 20 to May 3, flow to the Caloosahatchee was 800 cfs.
• On May 18, flow to the Caloosahatchee was increased to 800 cfs.
• From May 4 through May 17, flow to the Caloosahatchee was 600 cfs.
The St. Lucie Canal east of Lake Okeechobee received no lake releases for most of the dry season. No lake water was released at Port Mayaca during the period from Oct. 4, 2018, to Feb. 23, 2019. No lake water has been released at Port Mayaca since March 30. Flows to the St. Lucie Canal are measured at the St. Lucie Lock, which is 23.9 miles from Port Mayaca. Some flow measured at the St. Lucie Lock is from local basin runoff that drains into the St. Lucie Canal.
From March 16 to March 30, flow to St. Lucie, measured at the St. Lucie Lock was 250 cfs.
From Feb. 23 to March 15, flow to the St. Lucie was 500 cfs.
To get the latest information on Lake Okeechobee’s water volume, including daily levels, visit SFWMD’s website atsfwmd.gov/science-data/levels.
To get the latest information on navigation through SFWMD structures and waterways, visit sfwmd.gov/navigation.