Lake Okeechobee topped 16 feet over the weekend. On Monday, Nov. 14, the Big O was 16.18 feet above sea level.
When the lake reaches 16 feet, the U.S. Army Corps of Engineers increases inspections of the Herbert Hoover Dike, the earthen dam that surrounds Lake O for flood control. No problems with the dike have been reported.
Lake levels above 15.5 feet can damage the lake's marshes, which are the natural filtration system that cleans the water. At 15.5 feet, the marshes are completely inundated with water. As the lake level rises higher, the water stacks up against the side of the dike. If the water level rises faster than the plants can grow, the vegetation can be damaged or destroyed.
The lake was below schedule for most of the summer, but Hurricane Ian and Tropical Storm Nicole dropped significant rainfall north of the lake and that runoff is rapidly draining into Lake Okeechobee.
On Nov. 14, inflow into the lake was 5,568 cubic feet per second (cfs). That’s about 3.6 billion gallons per day. One inch on Lake Okeechobee equals about 12 billion gallons of water.
For the seven-day period ending Nov. 14, very little water was leaving the lake, with the exception of water lost to evapotranspiration (a combination of evaporation and plant transpiration.) Flow at the Julian Keen Jr. Lock in Moore Haven averaged just 32 cfs. The U.S. Army Corps of Engineers has set the target flow to the Caloosahatchee River at 1,200 cfs, measured at the Franklin Lock, which is more than 40 miles from Moore Haven. If there is sufficient local basin runoff to meet the target flow, no lake water is released. For the past week, most days local basin runoff met or exceeded the target. The average flow at the Franklin Lock for the seven-day period was 2,680 cfs.
No lake water has been released to the St. Lucie River since April 2021.
The most recent satellite imagery from the National Oceanic and Atmospheric Administration (NOAA) showed no algal bloom potential for most of the lake. No blooms have been reported. Routine water samplings did not detect any toxins. Of the 28 species of cyanobacteria (commonly called blue-green algae) documented by the U.S. Geological Survey in the Lake Okeechobee Waterway, about 25% are capable of producing toxins. However, cyanobacteria capable of producing toxins do not aways do so.
For the past week, flow south averaged 24 cfs. Rainfall south of the lake has filled the stormwater treatment areas (STAs) and Water Conservation Areas (WCAs), leaving no capacity to take lake water.
According to the South Florida Water Management District Environmental Conditions Report issued Nov. 9, the lakes within the Kissimmee Chain of Lakes are at their regulation schedules, which should provide plenty of water to hydrate the restored portions of the river floodplain this dry season. The weekly average dissolved oxygen levels in the river have increased from 1.2 mg/L to 1.3 mg/L. Oxygen levels below 1.0 mg/L are potentially lethal for largemouth bass. At 1.3mg/L, oxygen levels are still considered to be in the physiologically stressful range.