Dry season rainfall keeping Lake O high

Posted 1/24/24

The 2023-2024 dry season continues to bring above average rainfall, keeping the level of Lake Okeechobee above it’s “ecological envelope.”

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Dry season rainfall keeping Lake O high


The 2023-2024 dry season continues to bring above average rainfall, keeping the level of Lake Okeechobee above it’s “ecological envelope.”

On Jan. 24, Lake Okeechobee was 16.23 feet above seal level.

According to RECOVER, the lake’s normal ecological envelope ranges from 12 feet at the end of the dry season to 15 feet at the end of the wet season. The lake’s recovery envelope uses a low of 11.5 to 12.5 and a high of 14.5 to 15.5.

RECOVER (REstoration COordination & VERification) is a multi-agency team of scientists, modelers, planners and resource specialists who organize and apply scientific and technical information in ways that are essential in supporting the objectives of the Comprehensive Everglades Restoration Plan (CERP).

The lake needs the lower levels in order for sunlight to reach the lake bottom, causing new submerged aquatic vegetation (SAV) to sprout. The lake’s vegetation was devastated by Hurricane Ian in September 2022 and has not yet had a chance to recover. SAV provides critical habitat for the lake’s fisheries.

After Hurricane Ian, the U.S. Army Corps of Engineers (USACE) and South Florida Water Management District (SFWMD) used massive pumps to save the urban Orlando/Kissimmee areas from flooding. The excess flood water was pumped rapidly down the Kissimmee Chain of Lakes into the Kissimmee River and Lake Okeechobee, pushing the lake level up several feet.  The lake level has not yet recovered from that inflow. Since Ian, USACE has prioritized the health of the coastal estuaries and limited flow west to the beneficial target for the Caloosahatchee.

The lowest lake level for 2023, at the end of 2022-2023 dry season in June, was 13.7 feet. The big lake ended the 2023 “wet” season above 16 feet and remains high.

During a normal dry season, most of the water that leaves the big lake is via evapotranspiration (a combination of evaporation and plant transpiration.)  For the week of Jan. 15-21, SFWMD data shows Lake O had more water entering the lake by direct rainfall than leaving the lake by evapotranspiration.

According to SFWMD, for that seven-day period direct rainfall contributed 25,690 acre feet of water into the lake and surface water inflows were 55,840 acre feet. Evapotranspiration removed only 21,890 acre feet.

During a normal “dry” season, lake water flows south for agricultural irrigation and for urban water supply. This wet season, heavy rainfall south of the lake has meant lake water was not needed there. In addition, direct rainfall south of Lake O meant the stormwater treatment areas (STAs) south of Lake O had little capacity to accept flow from the lake. For the week of Jan. 15-21, flow south was just 350 acre feet.

The water conservation areas (WCAs) south of the lake are also high with WCA-2A 1.63 feet above schedule and WCA-3A 0.32 feet above schedule.

USACE is not releasing any lake water east to the St. Lucie (C-44 canal.) Flow west to the Caloosahatchee River has a target flow of 2,000 cubic feet per second, measured at the W.P. Franklin Lock, which is more than 43 miles from the Julian Keen Jr. Lock at Moore Haven, where lake water enters the river. The river needs freshwater flow from the lake during the dry season, and the target has been set in the beneficial flow range. If there is direct rainfall in the basin, less or no water is released from the lake.

For the seven-day period ending Jan. 24, flow at the Julian Keen Jr. Lock averaged just 226 cfs with most of the flow in the river coming from local basin runoff.

Anglers for Lake Okeechobee is encouraging those who care about the Big O to attend South Florida Water Management District meetings  to voice their concerns about the lake level. The next SFWMD Governing Board meeting is Feb. 8 at 9 a.m. 

lake okeechobee, rainfall, lake level