The sand dunes are coming!

That was the bottom line in Thursday’s monumental decision by the U.S. Army Corps of Engineers, who officially included Key Biscayne as part of Miami-Dade County’s 50-year Shoreline Protection Plan, saving the Village millions of dollars in the process.

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Village Manager Steve Williamson, calling it a “Super Bowl” win, said the plan to widen, raise and reinforce the dunes “really complements the rest of the work we’re doing,” and pointed specifically to the commitment by Village voters, who in 2020 said “yes” to the $100 million General Obligation Bond Referendum.

“The Corps of Engineers has been fully impressed with the Village’s commitment and work to date,” Williamson said. “The community support we have received, the team and plans we are building, and the passing of the General Obligation Bond have shown that Key Biscayne is looking to the future to address our risks and protect our residents, property and our thriving economy and vibrant lifestyle.”

The estimated $120 million project would come with a 65-35 split, with the federal funds accounting for the majority of the construction to elevate dunes, perhaps 5 to 7 feet with an overall height of 12 feet in some locations along the oceanside beach. The 35% split also would be divvied between the city, county and state in some fashion.

“Any money that we can get elsewhere is money that we can spend on other things that we can get done,” Dr. Roland Samimy, Chief Resiliency and Sustainability Officer, has said.

Just this week, Vision Board workshops are being held with stormwater upgrade designs — among other capital improvements to protect the island from impending sea level rise and flooding from major storms — being discussed by city leaders, the public and the DPZ CoDesign architects.

The Army Corps will be providing the bulk of the construction along the 1.2 miles of oceanside beach. Currently, the Village is evaluating how to protect the backside of the bay, a commitment which no doubt influenced the final decision.

Thursday, Williamson said the Army Corps will begin an additional process of a Biscayne Bay, or back-bay study, that will incorporate a whole-island solution to nature’s offerings. A second waiver will be required for that, and likely some, or most, of that work will be handled by the Village if earlier indications are correct.

“The Corps is looking at this holistically, and while it will take a little more time to complete, this additional study will result in a comprehensive solution that will prove to be more beneficial for the Village,” Dr. Samimy said.

The Army Corps’ investment calls for four lines of defense:

1. Periodic beach renourishment, calling for approximately $60 million of the $120 million total;

2. Dune enhancement and reinforcement with a buried sheet pile seawall and a concrete cap to reinforce the dunes;

3. Protective tie-back systems along the north and south of the Village; and

4. Complete vegetation of the dunes with walkover crossovers in some areas, preserving and enhancing the existing ecosystem and marine plants and fauna.

From here, the state and agency review final report comes out in August. Then, the final report from the Chief of Engineers is due in October, and engineering phases may begin no earlier than 2024.

Studies were conducted looking at the need over the next 50 years, using time-lapse technology with the highest-level sea rise as the model, and also comparing structural and nature-based features if alternative measures were used instead, such as simply replenishing sand every few years.

Now, with a plan calling for a reinforced dune wall with a concrete cap and tie-back walls along the northern and southern boundaries, Key Biscayne is headed into the meat of the overall $267.6 million project that includes construction and maintenance.

Key Biscayne’s low-lying elevation (3 feet) was a key in being selected to this point.

Officials with the Army Corps said engineers will be using the same footprint as they have done up the coast, where some dunes rise as high as 13 feet.

The “Main Segment” of the plan, from Bal Harbour to Miami Beach, would mean $40,552,000 in total benefits, including a whopping $36,817,000 in recreation benefits, earlier reports have indicated.

And, protecting the bayside area is a double win.

“This is a new direction and one that the Corps is comfortable with,” Williamson said, thanking Miami-Dade County officials and County Mayor Daniella Levine Cava for their support. “Creating a plan that incorporates the oceanside and bayside will be a benefit to our environment and our community.”


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