South Florida Water Managers Approved An Underground Flood Wall — And They Hope To Add More
South Florida water managers wrestling with ongoing flooding problems in a neighborhood bordering Everglades marshes have approved an underground seepage that could be the first leg in a miles-long wall separating the wetlands from Miami-Dade County.
The $14 million wall around the Las Palmas neighborhood will stretch more than two miles and reach 63-feet deep — or about five stories.
South Florida Water Management District governing board members, who said Thursday they anticipate extending the wall much further, also approved a contract that contemplates a far longer wall.
“This is a curtain wall that needs to be built and not just in the first phase, but all the way down,” said governing board member Scott Wagner, who represents Miami-Dade. “If this thing works and we can keep moving water south and can keep water in the park and keep the Homestead farmers in good shape, it's a home run for everybody.”
Last year, district staff began holding workshops on plans for an underground seepage wall, arguing that the wall could address flooding issues as water levels are raised in the park. According to a June presentation, water levels in Taylor Slough — on the park’s eastern boundary — have steadily increased and now peak at much higher levels than a decade ago.
Everglades restoration calls for moving more water into the old slough to help freshen Florida Bay, where decades of flood control have led to seagrass die-offs and too little freshwater.
Farmers and rock miners have long worried that higher water in the park could interfere with their operations.
“Conflicts between farming and Everglades restoration have really played out south of Miami,” said consultant Tom MacVicar, a former district hydrologist who works with the agricultural industry. “We're really gratified to see the district finally buy into the concept in a big way.”
But Miami-Dade County and Biscayne National Park have in the past raised concerns about cutting off groundwater, which helps replenish well fields and Biscayne Bay. Biscayne Bay has also suffered from widespread seagrass die-offs. Flood control wiped out water that once flowed across transverse glades and dried up underground springs on the bay bottom.
Climate change could also become a factor, as rainfall increases and groundwater rises with increased sea level.
“Even with the current wall, you’re still going to have flooding because with climate change and sea level rise, flooding is going to come from the other direction anyway,” said Drew Martin, a conservation chair at Sierra Club.
The district still wants to buy 119 properties from willing sellers in the Las Palmas neighborhood and asked Miami-Dade County to consider using money set aside for its Environmentally Endangered Lands program. The program is typically used to acquire pine rocklands and lands with endangered species.
But governing board members said they didn’t want drawn out negotiations with buyers to slow restoration progress.
“I hope this is the first of many miles that will be done,” said board member Charlie Martinez. “I hope soon we’re going to be able to extend this all the way down to South Dade.”
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