Lake Okeechobee discharges to the St. Lucie River will stop Friday; could they return?

Lake Okeechobee discharges to the St. Lucie River will stop Friday.

But they could start again if hurricane season kicks up and poses a threat, said Lt. Col. Jennifer Reynolds, the Army Corps of Engineers' deputy commander for Florida.

"We continue to monitor tropical activity, including a disturbance in the Gulf (of Mexico) that could potentially bring additional rain to South Florida next week," she said Thursday at a Water Resources Analysis Coalition meeting in West Palm Beach.

More:Historical data on Lake O discharges

More than 80 billion gallons of lake water has flowed into the river since the discharges began June 1, according to TCPalm estimates.

Toxic blue-green algae, red tide

Some of that water brought toxic blue-green algae with it, and algae blooms were scattered through the river for much of the summer.

At times, the blooms were highly toxic. An Aug. 2 water sample from Central Marine on the river's north shore in Stuart contained the toxin microcystin at a rate 11 times the level considered hazardous in recreational contact by the World Health Organization.

More: Blue-green algae bloom 10 times too toxic to touch

Now the Treasure Coast is getting red tide, which arrived on the east coast in September, from a bloom that's plagued the west coast since October 2017.

Red tide occurs naturally in the Atlantic Ocean and more so in the Gulf of Mexico, but blooms as it nears shore and gets fed by nutrients, mostly nitrogen and phosphorus from pollution sources such as Lake Okeechobee discharges.

More:Red tide confirmed on St. Lucie County beaches

More:Red tide confirmed at Martin County's Bathtub Beach 

Lake water has been flowing through the St. Lucie Lock and Dam at an average rate of 756.2 million gallons a day since mid-September. Flows in June and August were as high as 1.3 billion gallons a day.

Caloosahatchee River flow to slow

Discharges west to the Caloosahatchee River will ramp down significantly over the next three weeks, Reynolds also announced Thursday.

More:Army Corps must end carnage and stop discharges

More:Stop politicizing water problems and tackle them | Another view

Lake water has been flowing into the Caloosahatchee River at a rate of about 1.9 billion gallons a day. That will drop to about:

• 1.3 billion gallons a day Friday
• 970 million gallons a day Oct. 12
• 650 million gallons a day Oct. 19

Lake O's elevation was 14 feet, 4⅞ inches Thursday morning. The lake has dropped about 3 inches in the last week.

Hoping discharges don't resume

The St. Lucie River has suffered enough, said Mark Perry, executive director at the Florida Oceanographic Society in Stuart.

The estuary, which is supposed to be a combination of freshwater and saltwater essentially has been fresh for 120 days, Perry said.

That's more than long enough to kill many of the river's oysters and sea grasses, species that are the backbone of the estuary's ecosystem.

For the last couple of months, the discharges have been on a "pulse" schedule that includes a day of no flow from the lake, a break meant to allow tides to bring salty water into the estuary and help keep oysters and sea grass alive.

Although most of the river's algae blooms are gone, Perry said, there still are a lot of algae cells spread throughout the water, "even if it's not visible."