Corps of Engineers starts another Lake Okeechobee release to benefit Caloosahatchee Estuary

Published March 4, 2011

JACKSONVILLE, Fla. – The U.S. Army Corps of Engineers, Jacksonville District will continue water releases from Lake Okeechobee to the Caloosahatchee Estuary to help improve estuarine conditions, which have declined in recent months due to the lack of sufficient freshwater.  A new water release starts today, March 4.


The Corps will implement a series of pulse releases until the lake enters the water shortage management band, anticipated at about 11.70 feet (NGVD). The target flow of each release is an average of 300 cubic feet per second (cfs) over a seven-day period to the Caloosahatchee River measured at W.P. Franklin Lock and Dam (S-79). The Corps anticipates the effect on the lake level to be about a third-of-an-inch off the lake. Today, the lake stage is 12.05 feet (NGVD). 


The mixing of freshwater with seawater establishes salinity levels that are essential to Caloosahatchee's estuarine health, productivity and function.  The release will provide much needed support to the natural system, while minimally impacting Lake Okeechobee’s water level, scientists and water managers say.


“We recognize there are concerns about the lake’s recession and the potential for continued dry weather conditions.  We are monitoring conditions very closely.  This is an important spawning time for many species and we believe the freshwater releases are critical to help stabilize conditions in the Caloosahatchee Estuary until the rains begin,” said Lt. Col. Michael Kinard, deputy district commander, south Florida. 


The Corps will use the 2008 Lake Okeechobee Regulation Schedule (LORS) additional operational flexibility, with the objective of creating minimum freshwater releases to the Caloosahatchee River that are crucial to maintaining estuarine health and productivity.  Freshwater tape grass, which provides important food and nursery habitat, is an indicator of conditions in the Caloosahatchee’s upper estuary. During the onset of the spawning season, an array of estuarine larval organisms require low salinities for survival including anchovies, snook, commercially important crabs, and oysters.  Corps officials expect this week’s low volume release to continue prolonging the benefit of lowered salinities, reducing additional impacts and degradation of the freshwater tape grass and other submerged aquatic vegetation.   


The Corps strives to maintain the lake between 12.5 and 15.5 feet (NGVD) while balancing all competing demands.  At 12.05 feet (NGVD), Lake Okeechobee’s level is in the 2008 LORS Beneficial Use Sub-Band, which varies seasonally between elevation 10.5 feet and 13 feet.


Within this sub-band, unless releases are required for navigation purposes, the Corps generally defers to the South Florida Water Management District’s recommendation for water allocation to various users.  Fish and wildlife enhancement and/or water supply deliveries for environmental needs may involve conducting an environmental release from the lake through the SFWMD Adaptive Protocols for Lake Okeechobee Operations or other SFWMD authorities. 


The Corps and partner agencies will continue to closely monitor and assess system conditions.

Release no. 11-19