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HEALTH

Will El Nino or hurricanes bring Lake Okeechobee discharges and algae blooms in 2019?

Tyler Treadway
Treasure Coast Newspapers
Marva Porten (right) and her husband, Pete Porten, of Port St. Lucie, walk across the St. Lucie Lock and Dam in Martin County on Friday, June 29, 2018, while discharges from Lake Okeechobee began to slow. "Well, we were exploring, and we knew that they were still releasing water out of Lake O, and I was curious to see how much flow was coming," Pete said, adding that he wanted to see how much green algae was coming. "You can actually see it here."

A great new year's resolution for the Army Corps of Engineers would be to not discharge any Lake Okeechobee water to the St. Lucie and Caloosahatchee rivers in 2019.

Would it be a resolution the Corps can keep?

"First of all, we don't want to discharge water," spokesman John Campbell said. "I can't say there will be no discharges in 2019 because it will depend on the weather. But I can say that we're in better shape now than we were a year ago or in the past several years."

That's because Lake O is lower now than it's been in late December since 2010.

Ideally, the Corps would like Lake O's elevation to drop during the winter dry season (November through May) to 12 feet, 6 inches by June 1, the start of the summer rainy season.

The lake now, at an elevation of about 12 feet, 8 inches just a few weeks into the dry season, is only a couple of inches away from the June 1 goal.

But a low Lake O in late December is no guarantee the discharges will stay away in the coming year.

El Nino, on the left, and La Nina, on the right, are two conditions of ocean currents off the Pacific Ocean coast of Ecuador. Both water temperature conditions create weather patterns felt in North America and Florida.

The Little Boy (aka El Niño) 

A mischievous little boy — or El Niño , as he is known — could change things this winter.

To meteorologists, El Niño is a weather pattern in which warmer-than-average Pacific Ocean temperatures bring a strong subtropical jet stream across the southern United States; and that brings stormy weather to Florida.

In 2016, El Niño brought Florida its wettest winter on record, and that brought discharges starting in late January that dumped 237 billion gallons of Lake O water and massive toxic algae blooms in the St. Lucie River.

More: "The Dirty Dozen" Lake Okeechobee discharge events

But that was a strong El Niño; and the National Weather Service is predicting a weaker system this winter.

More: Expect colder, wetter winter on Treasure Coast

"The rains haven't come yet, but all the indications of what an El Niño is are there," John Mitnik, chief engineer at the South Florida Water Management District, told the board at its mid-December meeting. "Now we're just waiting for the water to come."

There's a 90 percent chance Florida will be in El Niño conditions sometime this winter, said Jessie Smith, a meteorologist at the weather service in Melbourne. "And it's expected to last through spring."

What a weak El Niño means, Smith said, "is temperatures remaining around normal, and rainfall slightly above normal. But at this point, we can't estimate how much extra rain we'll get."

Hurricane season

Fortunately, we'd need a lot of rain to trigger discharges — again because the lake is so low right now and has capacity to take on a lot of water without the immediate need for discharges, Campbell said.

"Immediate" is a key word here, because this summer, Mother Nature could play her wild card: hurricanes.

"Hurricanes and tropical storms are big precipitation-makers," Campbell said. "The most dramatic rises in the lake level have nearly all been influenced by tropical systems of some sort." 

Think back to 2017, when the lake stayed low — and there were no discharges — all winter, spring and summer. Then Hurricane Irma hit in mid-September, the lake jumped 3½ feet — and the resulting discharges lasted until late December.

Where rain falls matters

Where the rain falls — whether from El Nino in the winter or tropical systems in the summer — helps determine if there will be discharges, too.

Rain north of Lake Okeechobee is more likely to cause discharges than rain south of the lake. All the rain falling on Lake O's 1.5 million-acre watershed stretching as far north as Orlando has to fit into the 467,000-acre lake.

"An inch of train over three days is no big deal, but an inch in an hour or two is," Campbell said. "Water has the potential to flow into the lake a lot faster than we can get it out. And sometimes we have to release water from the lake to the estuaries to reduce flood risks."

Florida's plumbing

Florida's plumbing system from Orlando to the Keys was designed and built primarily to prevent flooding. And it does that really well.

Heavy rains in 1947 caused flooding that covered the majority of South Florida with water, in some places for more than six months, Lt. Col. Jennifer Reynolds, the Corps deputy commander for Florida, noted at a Sept. 22 water forum in Palm City.

"We got more rain in 2017 than we did in 1947," Reynolds said, "and there was no flooding."

More: Cutting discharges not that easy, Corps colonel says

The challenge, and the reason the state and federal government are investing so much in water projects like the EAA reservoir south of Lake Okeechobee, Campbell said, "is to make flood control more environmentally friendly."