Mangrove Reef Walls are seawall panels that create habitat, dissipate wave energy, and enhance the overall appearance of constructed shorelines. The panels mimic the form and function of red mangrove tree roots and oyster reefs that occur naturally in the State of Florida. These tidal ecosystems have seen a decline in coverage due to urban development and the construction of seawalls over the past century. Made from marine-friendly concrete, Mangrove Reef Walls can be cast integrally into a concrete seawall or precast and attached to an existing wall of any material. The panels are designed to accelerate the development of oyster reefs and other species along urbanized waterfronts to create healthier waterways in Florida and beyond. Mangrove trees and oyster reefs previously occupied much of the shoreline in Florida. These tidal shorelines are some of the most ecologically productive and important ecosystems on the planet, yet they are being lost at a rate faster than the tropical rainforests. Florida has tens of thousands of kilometers of canals that are mostly lined with concrete walls or hardened edges, which has led to a decline in habitat, loss of species, and degraded environment. In some areas of the state, greater than 90% of the natural shoreline has been converted into a hardened edge. Many canals in Florida are too narrow or deep to install living shorelines, and docks, boats and other shoreline features form the backbone to economies in coastal areas. Thus, in order to be sustainable, these constructed landscapes must somehow fill the void left in the function of tidal shorelines. In terms of design, molds for the panels are derived from parametrically modeled mangrove tree roots and oyster reefs and then digitally fabricated. The panels dramatically increase surface area and texture to provide a substrate for algae, oysters, barnacles, and other species that engineer the environment. The panel design aims to capitalize on habitat niches that correspond to the tidal zone within a vertical arrangement in the water column. Relief between roots creates zones for grazing species and smaller tunnels and pockets create gaps for juvenile crabs, snails, fish, and others to hide from predators. Shore birds perch and hunt for crab, fish, and other prey along the top of the panels, while larger predator fish utilize space below the panels to ambush prey. In this regard, the addition of the panels to a seawall restores much of the functioning of a tidal shoreline in waterways that may have limited space. In terms of materiality, the panels are made with high strength concrete with multiple additives. Oyster flour is added to temper the pH of the concrete to be more like seawater and encourage oyster development on the surface (oysters attract oysters). Natural fibers from coconut and palmetto trees are shredded and blended in for tensile reinforcement. Although concrete is suitable for many species to settle on, some marine organisms prefer softer substrates. Fuzzy rope and other aggregate materials are cast into the face of the panel to create this diverse substrate and promote more species to visit and settle on the panels. The goal of the research is to shift coastal design and construction practices toward sustainable solutions within a “blue” economy, and although far from a perfect solution, Mangrove Reef Walls are a step toward transforming coastal construction into ecologically productive landscapes.
Keith Van de Riet is principal and founder of Mangrove Reef Walls. He is a registered architect in Florida and holds a doctoral degree with emphasis in "Built Ecologies" from Rensselaer Polytechnic Institute. Van de Riet has experience in design and consulting on a variety of construction projects and technologies in New York, Florida, and Kansas. Currently teaching at University of Kansas Architecture, he runs a design-build studio and teaches topics in sustainability and biomimicry. His research activities include simulation and analysis of environmental systems and prototype testing and development for sustainable technologies.