Sea level rise threatens Miami’s future. Here’s how the Army Corps can help keep Florida, Florida.

Florida residents are on the frontlines of climate change, already facing sea level rise and increasing storm intensity. 

This is especially evident in Miami, due to its low-lying topography, porous limestone, dense coastal development and encroaching seas.  

To address these threats, the U.S. Army Corps of Engineers (Corps) produced the Miami-Dade Back Bay Coastal Storm Risk Management study. This multibillion-dollar proposal contains traditional, hardened infrastructure projects, including a massive seawall that would extend across Biscayne Bay in downtown Miami, reaching up to 20 feet in some places.

The proposal has received significant pushback from the public and stakeholders who are concerned about negative impacts to the environment, economy and quality of life.  

As the Corps seeks to address flood vulnerability in Miami and elsewhere, here are three ways the agency can reduce risk while also preserving the natural beauty of Florida’s coastal communities.

Harness nature to reduce flood risk and deliver additional benefits.

Seas are projected to rise in Miami-Dade County by more than 15 inches in the next 30 years, increasing flood risk further inland and with greater frequency.  

The encroaching seas threaten not only communities, but also the resources they rely on, including roads, drinking water and sewer lines.  

The Corps’ proposal should incorporate natural solutions to reduce these risks and deliver additional benefits, such as improving water quality, sequestering carbon, enhancing fish and wildlife habitat, and also creating jobs and economic development. 

Natural solutions make good business sense, as the costs of implementing features like mangroves and wetlands can be two to five times cheaper than traditional hardened infrastructure, while enhancing the performance of structural solutions. 

An oyster reef can provide an economic value between $5,500 and $99,000 per hectare annually and recover costs in two to 14 years. Coral reefs can provide the same benefits as low breakwaters at a fraction of the cost in addition to providing other ecosystem benefits. 

Figure 1. depicts an example of how a locally preferred alternative could improve upon the U.S. Army Corps of Engineers (USACE) Back Bay project design by incorporating natural infrastructure and by considering community needs. Credit: Miami Downtown Development Authority.

Engage the private sector to develop innovative approaches.

Swire Properties, a development firm with operations in Miami, hired engineering firm Moffatt & Nichol to develop a hybridized approach that includes natural and nature-based solutions in response to the Corps’ proposal. 

The Swire proposal calls for the installation of oyster reefs as a first line of defense from flooding followed by mangroves, a boardwalk, wetlands and more strategically placed and smaller scale seawalls. 

Swire’s involvement highlights how the private sector can help tackle the climate crisis. Often, these organizations have a vested interest and resources available to identify innovative solutions. 

Recently, the city’s Board of Commissioners and members of the public voiced support for Swire’s approach, articulating the need for more natural alternatives. 

Center community needs at the start of project planning. 

The Corps must understand and prioritize the needs and voices of people on the ground early in the planning process for resilience projects.

Local residents and stakeholders are too often engaged after an agency has already proposed a plan, as was the case with the Back Bay study, making it difficult to change or modify to address local feedback. 

A few years ago, Resilient 305 conducted exhaustive stakeholder outreach, which found local residents overwhelmingly prefer natural solutions. Residents understand the multiple benefits these solutions provide and how they can reduce risks while preserving the beauty of the ecosystem that makes Florida what it is. 

This engagement should include people outside of currently designated flood zones, as climate change will expand and increase areas of risk. Reducing the flood risk gap requires bringing diverse, representative groups to the table early and often.

Going forward, the Corps and other leaders can learn from these lessons of the Back Bay Study to prioritize long-term solutions that address flood risk and preserve environmental, economic and community wellbeing. 

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