Living Seawalls Enhance Shorelines

By: Guest Editors
Todd Barber, Founder of Reef Ball Foundation
Larry W. Stults, Ph.D., J.D., Chairman, Sarasota Bay Watch
Vera Cole, Reef Ball Foundation

Floridians are at the forefront of a tremendous opportunity. Since World War II, developers have been building hardened seawalls to safeguard valuable waterfront property from erosion. Their longevity is only about thirty years, so many are failing and in desperate need of attention. All along the Florida coast we are witnessing a massive collapse of thousands of miles of traditional sea walls.

In the coming years, these seawalls will need to be repaired or replaced. Are hardened vertical seawalls still the best solution? We don’t think so, and here are the four main reasons:

1. They do not manage wave energy well, and thus require tremendous amounts of material (and expense) in order to withstand constant wave action;

2. They reflect wave energy back into the water which impacts other seawalls and disturbs other shorelines;

3. They also direct wave energy downwards causing bottom scouring and preventing marine life from living in the benthic zone in front of the seawalls. This scouring action kicks up sediment into the water column, making the water turbid, diminishing sunlight penetration and inhibiting seagrass growth in our bays; and

4. Seawalls are very inhospitable to sea life, often replacing highly productive mangroves and other natural ecosystems. They are an extremely poor substitute for natural marine habitat.

Floridians now have the chance to build environmentally friendly seawalls to enhance and soften our shorelines. They are called living seawalls.

Living seawalls address the four major problems outlined above. They are designed to attenuate wave energy, so it is not reflected back into the waterway; they eliminate the bottom scouring and turbidity problems that are so detrimental to marine life; and, they are built to last much, much longer than vertical seawalls. Additionally, living seawalls manage wave energy so well that they require less material in their construction which is both good for the environment, and a less expensive solution for waterfront land owners.

Another important advantage of living seawalls is that they are specifically designed to create friendly marine habitat on a more natural looking shoreline. This, in turn, helps to increase the density and diversity of life in this important marine zone. For example, living seawalls can be constructed to have 3 separate ecological zones:

1. An underwater zone full of nooks and crannies that provide a protective nursery for sea life;

2. An inter-tidal zone that creates tidal pools and provides an area for shoreline grasses and mangroves to grow; and

3. An upland zone to attract other coastal life, such as seabirds, and for additional plantings.

The cost of living seawalls is currently comparable to traditional seawalls, but is expected to drop as economies of scale are realized. Additionally, the Army Corps of Engineers recently created a new nationwide permit that helps streamline the permitting process for environmental improvements like living seawalls. These two benefits will help boost interest in adopting solutions to soften our shorelines.

The City of Palmetto is ushering in this new era of eco-friendly seawalls. In April 2016 the City installed 970 feet of living seawall modules around the foot of the U.S. 41 bridge over the Manatee River, locally known as the Green Bridge for its color. In doing so, the bridge is now green in an all new sense, and represents the first step on the path to better shorelines locally, around Florida, and across the country that will foster more marine life, improve water quality and enhance our fisheries.

Join us on this exciting journey!

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