The U.S. Army Corps of Engineers (USACE) Jacksonville District will delay the previously announced sediment study scheduled for Nov. 9 after heavy rains across Florida led to heavier local basin runoff in the Caloosahatchee River Estuary than originally forecast.
The new date has not been finalized for the one-day deviation from the Lake Okeechobee Regulation Schedule that is part of an ongoing sediment study by the South Florida Water Management District (SFWMD) and the U.S. Geological Survey (USGS) to find ways to predict sediment and nutrient transportation from the lake to the estuaries.
Heavy rainfall across the state resulted in Lake Okeechobee rising from 15.83 feet on Nov. 4 to 16.02 feet on Nov. 7, a rise of more than two inches in three days. With local basin runoff in the Caloosahatchee River Estuary at times exceeding the current 2,000 cubic feet per second target for ecological releases, additional releases for this study would likely have led to releases in excess of the ecological envelope that is best for the health of the estuary.
“This is a very important study, but our partners at SFWMD and USGS asked to postpone the releases required for the research while the system deals with the water from this recent storm,” said Col. James Booth, commander of the Jacksonville District. “We still have several weeks left in hurricane season, and even normal storms can quickly change how we manage the lake. For now we are in a pretty good place on Lake Okeechobee and don’t anticipate any immediate releases beyond the current schedule.”
When executed, the deviation will allow up to 6,000 cubic feet per second (cfs) flow for short periods of time for up to 8 hours at the Julian Keen Jr. Lock and Dam (S-77). USACE executed a similar deviation in April to support the same study.
While the deviation allows for up 6,000 cfs releases in short durations, it is expected that the daily average flows will be closer to 1,600 cfs at S-77. Downstream flows at W.P. Franklin Lock and Dam (S-79) are expected to be elevated due to these releases for Nov. 9. The maximum effect of these releases on Lake Okeechobee stage is less than ¼ inch.