Environment

Florida’s coming King Tides may carry something different onshore — red tide

Return of the King Tide

As the king tide recedes, it leaves in its wake flooded beaches, parking lots, and streets inside Matheson Hammock Park on Sunday, September 9, 2018.
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As the king tide recedes, it leaves in its wake flooded beaches, parking lots, and streets inside Matheson Hammock Park on Sunday, September 9, 2018.

Red tide — a toxic algae that leads to human health problems and marine animal deaths — has arrived in Miami-Dade, just in time for the annual King Tides.

Scientists say this year’s annual highest high tides (popularly known as King Tide) could push that poisoned water further onshore, potentially spreading the algae’s health impacts inland.

“I’m hoping its going to be dead by then, but you can’t count on it,” said Stephen Leatherman, a coastal environmental scientist at Florida International University. “I’m hoping for the best.”

The city of Miami warned residents to avoid contact with floodwaters during the King Tides, which start October 6th and end October 13th, with a peak the morning of October 9. King Tides occur every year from September to November; this week’s tides are predicted to be the highest of 2018.

Climate change is expected to make these floods more severe and more common. Currently, tidal flooding drenches Miami-Dade cities like Miami and Miami Beach around six times a year. By 2030, the Union of Concerned Scientists predicts that number will jump to around 80 times a year, and more than 380 times a year by 2045.

This year’s King Tide might be the first with red tide, which is caused by the the bacteria Karenia brevis and can cause respiratory issues in humans and kill fish. That could leave the floodwaters more dangerous than normal, said Dr. Aileen Marty, a professor at FIU’s medical school. People and pets should stay clear of the infected water.

“Certainly don’t go wading in it,” she said. “Your feet will get blisters.”

Lab tests confirmed a “medium concentration” of the offending algae off Haulover Park, causing officials to close the beach to the public. Others tests revealed “very-low to low” levels off Miami Beach and Key Biscayne; officials did not close those beaches.

Leatherman said so far the red tide seems mild. It was likely weakened by the long journey from the west coast, where the phenomena is far more common. On the west coast, breakouts of red tide led to massive fish kills and paralyzed coastal tourism for weeks.

Miami-Dade County is sampling more beaches Thursday, including Golden Beach, south of Haulover and in Government Cut.

Health departments already warn residents to avoid King Tide floodwaters every year, which studies have shown pick up pollutants from the road and leaky septic tanks.

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This year, both cities have been fortifying their defenses against the rising tides for months.

The September King Tides were almost unoticeable; only four people called Miami’s 311 service to complain about flooding.

That week, Miami staffers flew drones and walked through neighborhoods searching for weak spots in the city’s defenses. Over the next few weeks the city installed backflow preventers, which allow water to flush out of pipes draining into the ocean but stop tidewater from flowing through the pipes and out of city drains, and temporary plugs.

The city plans to fund 40 more of these backflow preventer (or one-way tidal valves) values through the Miami Forever Bond, $200 millon of which is for sea level rise prevention efforts.

In addition to the city’s 13 full-time pumping stations, Miami plans to deploy five trailer diesel-powered temporary pumps throughout the city as needed.

In the floodprone Shorecrest neighborhood, city employees plan to install a 150-foot temporary dam at the waterfront Little River pocket park, which doesn’t have a sea wall, along with the three neighborhood backflow preventers and four plugs along 79th Street. Also on the street, a flashing sign warns neighbors to expect flooding soon. 

The Fairview neighborhood also got three new one-way tidal valves and will get a temporary tidal dam along the bridge at West Fairview Street.

Miami Beach is releasing traffic alerts for road closures caused by flooding (residents can sign up by texting MBTraffic to 888777) and offering free parking in a city garage for residents in flood zones. The city has 42 temporary pumps stationed throughout the island to handle excess floodwaters.

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