Lake Okeechobee discharges to St. Lucie River were 30 percent more than Army Corps reported

The 2017 Lake Okeechobee discharges were worse than we thought.

The South Florida Water Management District released figures Wednesday to TCPalm showing discharges to the St. Lucie River totaled 192 billion gallons.

That's 58 billion gallons more than the Army Corps of Engineers reported when the discharges, which started in mid-September, ended early Dec. 28.

The extra volume moves the 2017 discharges from the 12th largest to the ninth largest since 1965, the date the water district uses to start comparisons of water flow into the St. Lucie River.

More: Track the 2017 discharges and compare them to past events

The 2017 discharges now surpass the "Lost Summer" discharges of 2013, which dumped 136.4 billion gallons into the St. Lucie.

The Corps also reported discharges to the Caloosahatchee River totaled 347 billion gallons; the district's total is 397 billion gallons, an additional 50 billion gallons.

More: Lake Okeechobee discharges stop

Working with water district data, Stuart environmental engineer Gary Goforth confirmed the larger discharge amount to the St. Lucie River.

Goforth's estimate of discharges to the Caloosahatchee is 387 billion gallons, 40 billion gallons more than the Corps reported but 10 billion gallons less than the district's estimate.

Damage done

"The damage is already done, and it was extensive," said Mark Perry, executive director of the Florida Oceanographic Society in Stuart.

The 2017 discharges killed most of the oysters and sea grass beds in the St. Lucie River estuary and lagoon around the St. Lucie Inlet by wiping out the salinity they need to survive.

"As much as the volume of the discharges is important, so is the duration, how long they last," Perry said. "During the discharges last year, we had more than 70 days with basically zero salinity in the estuary. Oysters and sea grass just can't survive that."

More: Here's why the 2016 discharges didn't wipe out oysters

Goforth estimates the discharges dumped more than 155.7 million pounds of sediment in the St. Lucie River, while other canals and creeks added nearly another 14.4 million pounds.

All that sediment turned the water coffee brown, both in the river and in a plume that extended several miles out the St. Lucie Inlet and into the Atlantic Ocean.

It also was more bad news for marine animals. Oysters died when silt clogged the filters they use to feed, and sea grass couldn't photosynthesize food because silt kept sunlight from reaching the river floor.

Goforth also estimated the discharges dumped into the estuary:

360,774 pounds of phosphorus

2.97 million pounds of nitrogen

During the discharge period, canals, Ten Mile Creek and other creeks and ditches around the estuary added another:

807,412 pounds of phosphorus

2,245,310 pounds of nitrogen

Despite all the nutrients in the water, the 2017 discharges didn't spur toxic blue-green algae blooms like they did in 2016.

"That's really the only good thing you can say about the (2017) discharges," Perry said. "We didn't get an algae bloom."