Sydney is transforming its coastline with 3D-printed living seawalls, textured structures that mimic natural habitats like rock pools and mangroves. These aren’t your typical concrete defenses; they’re carefully designed to invite marine life back where it once thrived.
The Living Seawalls project, spearheaded by the Sydney Institute of Marine Science in collaboration with Reef Design Lab, uses digitally designed panels made from 3D-printed reusable molds that emulate the nooks and crevices of rocky shorelines.
Installed on existing seawalls in Sydney Harbour, these panels support a remarkable ecological comeback within one to two years. They sustain at least 36% more species than traditional flat seawalls, hosting up to 115 species of seaweed and invertebrates, just like natural rocky reefs. Fish also gravitate toward these surfaces, finding rich feeding grounds and sheltered zones.
In Rushcutters Bay, these panels have supported the growth of oyster and mussel populations, which naturally filter the water and, in turn, improve conditions for recreational activities along the bay. Impressively, over 2,500 of these panels have been installed globally. They also serve as powerful educational tools, engaging students at all levels to learn how green-engineering solutions can restore marine ecosystems.
At the same time, UNSW Sydney has introduced the BioShelters project, which provides an alternative yet complementary solution. Designed by computational architects at UNSW’s School of Built Environment, these are 3D-printed recycled-plastic molds, later filled with concrete that includes crushed oyster shells, an ingredient meant to encourage oyster colonization. Measuring roughly six meters by two meters and standing 90 centimetres tall in segmented panels, BioShelters have recently been installed at the new Sydney Fish Market site in Glebe, an area long drained of natural shoreline diversity.
Professor M. Hank Haeusler likens the situation to a “housing crisis” for sea creatures, especially oysters, and says the goal is to create artificial habitats that feel as natural as possible.
These structures are designed using marine-biology-informed algorithms and robotic fabrication, aiming to serve oysters, kelp, seaweed, fish, and other marine organisms. Prototypes were tested under the Anzac Bridge in 2020, and after just six months, they were already colonized by oysters, seaweed, kelp, and small fish. Now, the Fish Market installation is permanent.
The UNSW team hopes to print directly in concrete and streamline the design-to-fabrication pipeline one day, enabling marine biologists to input site data into a design platform and generate custom-made habitats for anywhere in the world. They’ve already begun conversations about expanding BioShelters across Sydney Harbour’s seawalls, and intriguingly, the same modular, habitat-driven design principles could someday extend to artificial homes for mammals, birds, bats, or rodents in need of refuge.
The rise of Living Seawalls and BioShelters in Sydney represents a way in which urban spaces can coexist with ecological systems. Computational design and 3D printing, once seen mainly as experimental design tools, are now being applied directly to solve ecological challenges.
Image credit: © Living SeaWalls
