Coastal Innovation: New Designs Bring Wildlife Back to Seawalls

At the edge of a canal in Pompano Beach, Florida, a small experiment is underway – one that speaks to a larger reckoning with how humans have reshaped coastlines and the consequences for marine life. A marine construction company is installing specially designed planters onto a new seawall, aiming to recreate some of the habitat lost when natural shorelines are replaced with hardened structures. This effort, highlighted by NPR, isn’t just about aesthetics; it’s a response to the growing understanding that traditional coastal defenses can inadvertently harm the ecosystems they’re meant to protect.

For decades, seawalls have been a standard feature of coastal development, offering protection from erosion and storm surge. But these structures, typically made of reinforced concrete, create a stark, unnatural barrier. As Arthur Tiedeman, of APH Marine Construction, explains, a seawall is “just a straight giant wall,” lacking the complex textures and crevices that marine organisms need to thrive. This realization is prompting a shift towards more nature-inspired designs, seeking to integrate ecological benefits into coastal infrastructure.

The “Forgotten Edge” and the Loss of Habitat

The problem, as Keith Van de Riet, a professor at the University of Kansas and the designer of the new planters, describes it, is that seawalls represent a “forgotten edge.” Historically, these areas would have been dynamic intertidal zones – a mix of mangroves, sand, and oyster beds. Dredging and construction have collapsed this rich habitat into a single, vertical surface. Oysters, crabs, and fish depend on these complex environments for shelter, feeding, and breeding. The smooth, featureless surface of a modern seawall offers little of that.

This isn’t simply an aesthetic concern. Declining fish populations, like grouper and snapper, are a growing issue in South Florida, as WLRN reported in 2022. Water quality is also deteriorating, with a recent report indicating worsening conditions in Biscayne Bay. The loss of natural habitat contributes to these problems, and the increasing replacement of older seawalls with even smoother materials – steel or vinyl – exacerbates the issue.

Mimicking Nature: The Design of the Planters

Van de Riet’s planters are designed to address this problem by mimicking the texture of natural oyster reefs and mangrove roots. They are “pockmarked and rough-cut; etched and grooved” to provide surfaces where tiny organisms can take hold. The idea is to create small pockets of habitat on the seawall, offering a foothold for marine life. This approach isn’t unique; there’s a growing market for “living seawalls” and artificial reef structures designed to enhance biodiversity. Miami Beach recently installed its first “living seawall”, a similar structure designed to provide habitat and storm protection.

These innovations are part of a broader trend towards incorporating ecological considerations into infrastructure design. Property owners are increasingly exploring options like artificial reef balls and vertical oyster gardens. However, Rachel Gittman, a coastal ecologist at East Carolina University, cautions that not all of these products are equally effective. Emulating the complexity of natural ecosystems is a significant challenge.

The Scale of the Problem and the Need for Policy Changes

The challenge extends beyond individual property owners. A 2021 study found that only about 15% of the world’s coastal regions remain ecologically intact, highlighting the widespread degradation of these ecosystems. Gittman emphasizes that restoring coastlines will require significant policy changes at both the national and local levels. In South Florida, where much of the coastline is privately owned, securing buy-in from homeowners is also crucial.

The current situation represents a critical juncture. As older seawalls reach the end of their lifespan, there’s an opportunity to rebuild them in a way that supports both human development and ecological health. Van de Riet believes that “we have to look at these hybrid models,” incorporating elements of nature into infrastructure. However, Gittman warns that simply replicating natural features isn’t enough; a deeper understanding of ecological processes is needed to ensure that these interventions are truly effective.

The “Seawall Pandemic” and the Future of Coastal Protection

Tiedeman refers to the aging seawalls as a “seawall pandemic,” highlighting the widespread need for replacement and repair. This presents both a challenge and an opportunity. The cost of replacing these structures is substantial, but it also provides a chance to incorporate more sustainable designs. The question is whether policymakers and property owners will prioritize ecological benefits alongside traditional engineering considerations.

The success of these efforts will depend on ongoing research and monitoring. It’s essential to evaluate the effectiveness of different approaches and adapt strategies based on what works. The experiment in Pompano Beach, with its innovative planters, is a small step in that direction, but it underscores the need for a more holistic approach to coastal management. The future of Florida’s coastlines – and those around the world – may depend on it.

Looking ahead, the focus will likely be on refining these nature-inspired designs and scaling up their implementation. Further research is needed to understand how these interventions interact with other environmental stressors, such as climate change and pollution. The process of adapting coastal infrastructure will be ongoing, requiring continuous monitoring, evaluation, and adjustment.