Irma sent phosphorus overload into lake

OKEECHOBEE — Lake Okeechobee is suffering from “weather whiplash,” thanks to Hurricane Irma.

At the Sept. 6 Water Resources Analysis Coalition meeting at the South Florida Water Management District Office in West Palm Beach, Drew Bartlett, Deputy Secretary Florida Department of Environmental Protection Office of Ecosystem Restoration, said the phosphorus load into Lake Okeechobee for the past year was nearly 10 times the target load set by FDEP.

According to Mr. Bartlett, during Water Year 2018 (May 1, 2017 through April 2018) the phosphorus load into Lake Okeechobee was 1,046 metric tons. The FDEP annual maximum target for the lake is 105 metric tons.

Most of that overload — around 700 metric tons — flowed into the lake in September and October 2017.

By comparison, during the very wet Water Year 2016, the phosphorus load was 508 metric tons.

The 2012-2017 five-year average was 369 metric tons, he continued, which showed that prior to the hurricane, FDEP was making progress in reducing the nutrient load into the lake.

“Nutrient pollution is the largest challenge in the state,” he said.

He explained that TMDLs (total maximum daily loads) have been set for Caloosahatchee, St. Lucie and Lake Okeechobee.

The reductions accomplished so far were due to Best Management Practices (BMPs) required for agriculture. According to the Institute of Food and Agricultural Services, BMPs include things such as fencing beef cattle away from waterways, using retention ponds and spray fields to control runoff, and limiting use of fertilizers.

“Anyone who thinks a best management practice for agriculture is voluntary, you’re wrong. They are mandatory,” said Mr. Bartlett.

He said FDEP has completed lagoon remediation for the former dairies in the watershed.

Prior to 1989, there were about 50 dairies in the watershed north of the lake. The FDEP Dairy Rule set strict limits for the nutrient load in the runoff from the dairies. Most of the dairies could not meet the standard and moved out of the watershed. Those that remained use berms, retention ponds and spray fields to catch and recycle the runoff.

However, even with the cows gone, there was concern the nutrient load left behind on the former dairies would continue to contribute to high phosphorus levels in the runoff for 20 years. This was the reason for the remediation projects at former dairies.

To achieve the phosphorus reduction target, it will take more than agriculture BMPs, he said.

“You can’t alter a water basin and expect the same flow downstream,” he explained.

He said FDEP scientists have been studying the causes of massive 2017 phosphorus load.

The Irma flow was intense, he said, but other hurricanes have dumped more rain in the watershed without such a drastic change in the phosphorus load.

Even in 2004, when Hurricanes Charley, Frances, Ivan and Jeanne went through the watershed, the phosphorus level did not get that high.

“In 2017, in May we had very little flow, almost no flow,” Mr. Bartlett continued. “In 2017, we were in a drought. Prior to June 2017 there were months of no flow.”

He said the watersheds north of the lake dried up prior to the hurricane, setting the scene for the “weather-whiplash effect.”

Headwaters of the Kissimmee River that flows into Lake Okeechobee.

“If you have a long period of drought, and then an intense rain, you are going to have a jump in phosphorus concentration,” Mr. Bartlett said.

“508 metric tons is not acceptable,” he said. “1,000 metric tons is not acceptable.

“We need to get to 105.”

“With the investments in BMPs and with the investments in projects, we are seeing lower concentrations coming into the lake,” he said. “We still have a long way to go.”

The Lake Okeechobee Basin Management Plan review will be concluded by December 2019.

“We will have to look at Lake Okeechobee, put the projects on the table,” he continued.

“We’ve got a goal to hit, 105 metric tons. That’s hard. I’m not going to say impossible. If I start saying impossible, I am encouraging people to give up.”

Publisher/Editor Katrina Elsken can be reached at kelsken@newszap.com

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