Biophilic Seawall

Our proposal investigates how concrete can create a symbiotic relationship between people and marine life, simultaneously making coastal communities more resilient to the effects of climate change and slowing or reversing the phenomenon of diminishing biodiversity in our oceans. Seawalls in coastal communities play an important role as the threshold between land and water. Water levels are rising and waterfront communities are becoming more vulnerable to floods and receding shorelines. Our project looks to design a modular seawall system to protect the shoreline. The units of the wall geometrically interlock to be easily assembled and disassembled and to eliminate the need for steel reinforcements and grout. The modularity allows for future additions to be made to accommodate rising sea levels and provides biophilic design opportunities to enable the increase of biodiversity at the hard coastline.

The Ocean Living Planet Index indicates that overall, marine species have declined by 52% and the world coral reefs decreased by 50% from 1970 to 2010. These trends result from anthropogenic causes like overfishing and from effects of climate change such as ocean acidification and warming temperatures decimating reef structures that are crucial to marine ecosystems. The Reef Ball Foundation paved the way for using concrete to create artificial reef structures for oysters and fish to inhabit. Other researchers including Uddin, Smith, and Hargis developed a concrete mixture called POSH that proves to be superior in cost, durability, environmental benefits, and lower carbon footprint for reef restoration. Concrete has also been proven to be an effective protection against tidal energy impacts and coastal erosion. Evidence that vessel wake stress is driving ecosystem loss, and living shoreline structures designed to reduce this energy can slow or reverse ecosystem decline.

The sea wall design is primarily made up of two base units, with variations for different functions, that are repeated in a specific order to create an interlocking system. Florida State University’s Climate Center estimates the US will experience a sea level rise of 1.96 – 7.22 ft by the year 2100 and 2.62 – 12.8 ft by the year 2150, relative to sea levels in 2000. Many seawalls will have to be torn down and replaced to account for this. The way our design is aggregated together to form the seawall allows it to be easily added on to meet the demands of sea level rise, reducing the need for replacement, thus reducing waste.  The design allows for one unit to be arrayed and rotated to create a gap where the second unit fits into. This second unit acts as a locking key, providing stability. On the seaward side of the wall, variations in the units are designed with biophilic properties to create natural marine habitats to promote biodiversity. Different biophilic structures can be plugged into the seawall: a tide pool unit to protect juvenile fish species during low tides, a mangrove root unit for oyster growth, marine mattresses to reduce wave energy, and a vegetation unit designed to promote seagrass growth.

The molds for these concrete units are designed to be reusable to minimize formwork waste. The molds are made from expanded polystyrene foam, cut with a hot wire tool attached to a Kuka KR120 robotic arm. The cut foam pieces are then coated with epoxy and assembled to be ready to cast into.

.