The takeaway message:

A new study from the U.S. Army Corps of Engineers and Miami-Dade County outlines a plan to address coastal storm impacts and improve resilience in one of the nation’s most vulnerable coastal areas. While the plan proposes manmade solutions like flood walls, some residents say the region would be better off improving natural storm buffers like wetlands and coral reefs.

What’s going on?

The U.S. Army Corps of Engineers and Miami-Dade County released a study on May 29 that proposed a plan to protect the area from damaging storm surge. The nearly $4.6 billion plan suggests building more hard structures like flood gates and flood walls while elevating approximately 2,300 low-lying structures. The project is not yet finalized, and eight alternative solutions have also been proposed. The Corps says the plan does not address tidal flooding, also known as sunny day flooding.

Members of the public are invited to submit comments on the proposed plan by Aug. 19. Similar storm surge plans are underway for Monroe County and other coastal communities in Florida, though none as large-scale and costly as what is proposed for Miami.

The plan aims to account for environmental health, human safety and the negative economic impact caused by storms. However, the Army Corps acknowledges that its plan only focuses on the most at-risk areas and that more studies will be needed to measure environmental consequences.

Some residents have voiced concerns about the new structures being damaging to aquatic plants and wildlife. Others also say that restoring and improving natural storm buffers, like coral reefs, mangroves and wetlands, would be more beneficial and cheaper than the planned manmade designs.

Why it matters.

Miami-Dade County is home to more than 2.7 million people and is a metropolitan economic hub for the region, with its bustling airport and cargo port being its biggest revenue drivers. But, Resources for the Future, a nonpartisan economic think tank, calls Miami “the most vulnerable coastal city in the world,” when it comes to costly flood events.

But Miami isn’t alone: Four of the top eight cities in the U.S. most vulnerable to storm surge are in Florida. Scientists note that climate change-induced sea level rise may increase the frequency and magnitude of storm surges and floods, and Florida’s vulnerable coastal cities could become increasingly threatened.

When a hurricane or tropical storm approaches land, water can rise dramatically over already-elevated tides and is pushed onto the shore – a phenomenon known as storm surge. This huge increase in water can cause extreme flooding, which damages infrastructure, puts citizens at risk for drowning and cuts off evacuation routes. This sheer force of water can erode roads and marinas, kill animals and vegetation and even knock over buildings.

That’s why cities are looking into resilience solutions, like the Corps’ plan for Miami, but the methods of how to do so run the gamut. Examples of manmade infrastructure include seawalls, which block wave energy that might erode beaches, and flood gates, which help control water levels and flow. Green infrastructure can include wetlands, which suck up extra water to prevent flooding, or mangroves, which block wave action.

NOAA’s Office for Coastal Management estimates coastal wetlands provide $23.2 billion in storm protection services to the U.S. each year, and cities in Michigan, Alabama and Illinois have already implemented natural solutions. However, many leaders still look to manmade options, like sea walls and jetties. The Miami Beach Times reports that Florida may spend $74 billion on seawalls by 2040. A long-term solution is still not agreed upon, and it might take a combination of these tactics to preserve Florida’s coastlines for future generations.

What can I do?

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