Miami-Dade Flooding Could Double as Engineers Start Identifying Miles of Risky U.S. Coast

With sea rise projections growing ever grimmer — the latest predicts up to eight times as much flooding around Miami-Dade County by 2045 — the U.S. Army Corps of Engineers has launched an ambitious plan to come up with a comprehensive assessment of risks that could easily run into the billions of dollars.

Covering 10,000 miles of vulnerable shoreline from North Carolina to Mississippi, the study for the first time tries to unify what has so far been a patchwork of sea rise assessments.

“You’ll have a common framework,” that creates an equal playing field in the fierce competition for federal dollars, said Col. Jason Kirk, commander of the Corps’ Jacksonville District, which includes Florida and the Caribbean, two of the most vulnerable regions to seas creeping upward.

In the most recent study of South Florida sea rise, researchers with the Union of Concerned Scientists used the Corps’ revised 2015 calculations for sea rise and found that far more swaths of Miami-Dade County will flood than under a projection they developed only a year earlier with more conservative estimates.  The group focused on five cities — Miami, Miami Beach, Key Biscayne, Hialeah and Coral Gables — and found the number of projected floods rose from 45 a year to 80 with a 10-inch rise in sea levels by 2030.

“We wanted to use projections that we felt better reflected what the county is using and the work coming out,” said Nicole Hernandez Hammer, the group’s Southeast Climate Advocate based in Miami.  “The reality is we’re already starting to feel the impacts of sea level rise.”

Figuring out how to prepare South Florida has so far been left mostly to local agencies, the study found.  Miami-Dade County formed its first sea rise task force in 2006, followed by a regional compact between Miami-Dade and three neighboring counties including Monroe, Broward, and Palm Beach.  Miami Beach — which drew global attention with ongoing reconstruction and plans to install a series of massive pumps — and Miami are also working on plans.  Last year, the South Florida Water Management District reassessed canals, flood gates and other structures and is in the midst of shoring up a major canal, the C-4, along the Tamiami Trail.  But so far, the state has no comprehensive plan.  And that has led to uneven preparation.

“At the municipal level, where the rubber meets the road, some cities are taking action but face serious barriers,” the UCS report concluded, singling out Opa-locka as an example where low-income communities may struggle to keep up.

“There is a high sense of urgency for initiatives to move forward and address sea level rise from the state and federally,” Hammer said.

The Corps assessment attempts to fill that gap, officials said.  The agency had been working to find a better way to address sea rise when Superstorm Sandy struck the east coast in 2012. The massive destruction leveled by the storm prompted an autopsy of the region’s failed infrastructure and led to a number of reforms and massive resiliency projects, including an unprecedented $20 billion storm protection plan from former Mayor Michael Bloomberg.

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