The U.S. Army Corps of Engineers (USACE) Jacksonville District plans to execute a minor deviation Tuesday, Aug. 23 that will release water from Lake Okeechobee as part of an ongoing sediment study by the South Florida Water Management District (SFWMD) and the U.S. Geological Survey (USGS).

The releases will affect only the Julian Keen, Jr. Lock and Dam (S-77) as water is released to support the study.

The initial releases are planned for the morning of Tuesday, Aug. 23 at S-77 and are expected to last for a maximum of four hours of flows not to exceed 700 cubic feet per second, followed by 500 cubic feet per second in the afternoon, for a maximum of four hours.

The purpose of study is to better understand nutrient and sediment transport to the estuaries under different flow conditions. USACE executed similar deviations in 2021 and earlier in 2022 to support the same study.

During the collection period, the S-77 is required to be open to take sediment measurements. This deviation allows the USACE to open S-77 for a relatively short period of time, even though flows at S-79 will be above the flow target of 479 cubic feet per second.

The estimated total volume for the releases is 650 acre-feet, which is the equivalent of 0.001 feet, less than a tenth of an inch on the lake.

No downstream impacts are expected in the Caloosahatchee River Estuary due to the short duration of the study.

This important research will help understand the relationship between suspended sediment concentrations, how they originate, how they carry nutrients, and how that might impact algal bloom development and growth.

USACE will monitor conditions and work with USGS and SFWMD to adjust flows for these studies as necessary if conditions on the lake or in the estuaries change.