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SCCF Asks Corps to Increase Lake O Flows
While the water often looks beautiful around Sanibel this time of year, there can be negative impacts if the estuary doesn’t receive enough freshwater. Photo by Rob Hoovis.
On May 2, SCCF Environmental Policy Director Matt DePaolis submitted comments to U.S. Army Corps of Engineers Jacksonville District, urging the Corps to restore optimal flows from Lake Okeechobee to the Caloosahatchee Estuary until we begin receiving more rainfall.
During the dry season, the Caloosahatchee requires freshwater flows of at least 750 cubic feet per second (cfs) to maintain the right salinities for important species like oysters and seagrass. The Army Corps reduced Lake Okeechobee flows to the Franklin Lock & Dam (S-79) to 650 cfs in mid-April, and on May 2, releases were lowered again to 500 cfs.
Because there is little to no precipitation this time of year, releases from Lake Okeechobee are the estuary’s main source of freshwater.
“As the end of dry season nears, we urge you to thoughtfully consider the delicate salinity balance required in the Caloosahatchee Estuary for oyster spawning to be successful, and to ensure the survival of critical species with specific salinity tolerances,” DePaolis wrote in the May 2 comment letter. “Data collected at Shell Point the week of April 15, following a lowered pulse schedule to a 650 cfs target, reflected a weekly average salinity of 29 practical salinity units (psu). The optimum salinity envelope for oysters as outlined in RECOVER 2020 metrics is 10-25 psu, meaning salinities quickly surpassed this target range following the revised flow schedule.”
With oyster spawning season already underway, DePaolis asked the Army Corps to consider restoring lake flows to optimum flow levels.
“We urge water managers to consider the delicate balance the Caloosahatchee Estuary relies upon when managing S-79’s flow schedule and the harmful effects elevated salinities will have on dependent species and communities for generations,” he wrote.
Once online this summer, the C-43 Reservoir will lessen our estuary’s dependence on lake flows during the dry season. This reservoir will store excess water when Lake O flows are too high and can release that water when flows are too low.
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