Corps of Engineers conducts Lake Okeechobee releases to benefit Caloosahatchee Estuary

Published Feb. 3, 2011

JACKSONVILLE, Fla. (Feb. 3, 2011) – The U.S. Army Corps of Engineers, Jacksonville District will start a water release from Lake Okeechobee to the Caloosahatchee Estuary to help improve the estuary’s condition, which has declined in recent months due to the lack of fresh water.  A new water release starts Feb. 4.


The target flow of this release is an average of 300 cubic feet per second (cfs) over a seven-day period to the Caloosahatchee Estuary, measured at W.P. Franklin Lock and Dam (S-79). The Corps anticipates the total pulse release effect on the lake level to be about a sixth-of-an-inch off the lake. Today, the lake stage is 12.49 feet (NGVD). 


The Corps approved water releases from Lake Okeechobee to the estuary Jan. 28, while the lake stage was at 12.50 feet (NGVD).  However, in accordance with adaptive protocols, the Corps did not release water due to local basin conditions. Local basin runoff from last week’s rain event, measured at W.P. Franklin Lock and Dam, exceeded the release target of 300 cfs.  This week’s low volume release, in conjunction with the recent rain event, will prolong the benefit of lowered salinities and reduce additional impacts and degradation of submerged aquatic vegetation. 


Estuary scientists say minimum freshwater releases to the Caloosahatchee Estuary are critical in maintaining estuarine health and productivity.  Freshwater tape grass, which provides important nursery habitat for a multitude of organisms, is an indicator of conditions in the Caloosahatchee’s upper estuary.  A continuous low-level release is needed to keep salinities from rising and negatively affecting more tape grass beds. 


“This freshwater is vital to the health, productivity and function of the Caloosahatchee Estuary. The release will provide much needed support to the natural system, while minimally impacting Lake Okeechobee’s water level,” said Lt. Col. Michael Kinard, deputy district commander, south Florida. 


The Corps strives to maintain the lake between 12.5 and 15.5 feet (NGVD) while balancing all competing demands.  At 12.49 feet (NGVD), Lake Okeechobee’s level is in the 2008 Lake Okeechobee Regulation Schedule’s 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.  Due to the estuary’s poor condition and forecasted insufficient basin runoff, the SFWMD recommendation to the Corps was releases up to 300 cfs to the Caloosahatchee Estuary. The Corps may adjust this release, as appropriate, to account for local basin runoff.


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

Release no. 11-11