Despite Dorian, Army Corps won't start Lake Okeechobee discharges to St. Lucie River yet
Less rainfall than expected from Hurricane Dorian plus efforts to keep Lake Okeechobee low add up to no discharges to the St. Lucie and Caloosahatchee rivers.
Not yet, at least, Col. Andrew Kelly, the Army Corps of Engineers commander for Florida, said Friday afternoon.
"My concern is the next one coming," Kelly said, noting "a lot of action" in the Atlantic Ocean and a hurricane season that doesn't end until Nov. 30.
The Corps will monitor storms in the Atlantic and update its assessment on the need for discharges "on a weekly basis," Kelly said.
Instead of discharges, the South Florida Water Management District is moving about 1.3 billion gallons of water south from Lake O each day and holding more water in lakes to the north.
The combination of keeping water out of the lake and getting water in the lake out is the best way to "avoid harmful discharges in the future," said SFWMD Executive Director Drew Bartlett.
High-flow releases expected
Prior to Dorian's arrival, Kelly had said to expect several months of "high-flow releases" from Lake O to the St. Lucie and Caloosahatchee rivers after Dorian.
But that was based on early predictions Florida would take a direct hit; and all the rain on Lake O's 1.5 million-acre watershed, which stretches as far north as Orlando, pouring into the 467,000-acre lake would raise it about 3 feet, 6 inches in 30 days.
After Dorian passed, the Corps revised its prediction, saying the lake should rise about a foot by late September.
The lake has risen slightly more than 4 inches in the last week, and not quite 2 feet in the last 30 days.
Lake O's elevation Friday morning was just shy of 14 feet. The average level for Sept. 6 is about 14 feet, 4 inches.
The Corps' effort to bring the lake's elevation lower than normal this year has helped reduce the need for discharges during the rainy season, when harmful algae blooms are more likely.
As of this week, Corps water managers can discharge Lake O water if they want to. For much of the summer, the lake has been lower than the C-44 Canal leading to the St. Lucie River. As of Thursday morning, the canal was about a foot lower than the lake.
No algae, just dirty water
Gates at the St. Lucie Lock and Dam were closed Thursday, but in the last week, about 2.8 billion gallons of water has poured through the dam into the river — all of it rainfall runoff from the farmland along the C-44 Canal between Lake O and the dam.
A crew from the water management district reported seeing no blue-green algae on the lake side of the Port Mayaca Lock and Dam, the site where Lake O water is released during discharges to the St. Lucie.
But even without the risk of a blue-green algae bloom, the St. Lucie River doesn't need any Lake O water.
In its weekly report issued Thursday, the Stuart-based Florida Oceanographic Society gave water quality in the river's estuary a D-plus grade, mostly because of low salinity and poor clarity caused by inflows of dirty water from canals that artificially extend the river's watershed into western Martin and St. Lucie counties.
Salinity in the river's South Fork was a dangerously low 1.45 parts per thousand Friday morning at the Palm City Bridge, according to a Kilroy remote-controlled monitor installed by the Ocean Research & Conservation Association in Fort Pierce.
Salinity there should be between 15 and 25 parts per thousand to ensure healthy oyster beds, a key to maintaining the river's ecosystem.
The Corps stopped discharges to the Caloosahatchee River on Florida's west coast when the local runoff got to be more than enough to hold back saltwater intrusion, the reason that river, unlike the St. Lucie, needs discharges during the dry season.