San Francisco’s waterfront seawall has protected the city’s roads, transit systems, businesses, and infrastructure for more than a century. The problem is that the long stretch of concrete has not exactly been friendly to marine life. Now, scientists and engineers are trying to change that with the San Francisco Living Seawall Pilot Project. Instead of treating the seawall like a barrier between the city and nature, they are turning parts of it into habitat by adding specially designed textured tiles that give oysters, seaweed, crabs, and other marine life places to grow and shelter. During the last 150 years, San Francisco’s waterfront has been transformed from natural marshes and rocky shoreline into a heavily built-up stretch of concrete designed to protect the growing city from flooding and erosion. While the seawall helped the city expand, it also destroyed many of the natural habitats marine life once depended on.
Traditional seawalls are usually smooth concrete surfaces. They protect cities, but they do not offer much shelter for marine life. Natural shorelines, on the other hand, are full of cracks, crevices, tide pools, and uneven surfaces where organisms can cling, hide, and grow. Living seawalls aim to bring some of that natural texture back into urban waterfronts. That idea inspired the San Francisco Living Seawall Pilot Project, launched in 2022 by the Port of San Francisco and the Smithsonian Environmental Research Center. The project tested whether specially designed textured tiles attached to the seawall could help create new spaces for marine life to live and grow along the city’s manmade waterfront.
The Living Seawall project became a three-year field experiment, installing specially designed tiles at locations including Pier 45 Breakwater, Pier 14, and South Beach Harbor. Hundreds of tiles were placed at different tidal heights to observe how marine life responded over time. The results were encouraging. Oysters, seaweed, crabs, snails, mussels, and algae began building small thriving ecosystems on many of the tiles, transforming sections of the seawall into something closer to living reef patches than plain concrete. Not all the tiles were identical. Researchers tested different textures and designs — including grooves, ridges, pits, wave-like surfaces, and small tide pool-style pockets — to see which features best supported marine life. These details matter because they create tiny shelters where organisms can anchor themselves and survive changing environmental conditions.
Scientists and crews regularly photographed and monitored the tiles, while some were removed and sent to laboratories for deeper analysis. Over time, each tile developed into its own miniature underwater world, evolving from a blank concrete surface into a busy habitat filled with marine organisms. Living seawalls are part of a growing movement known as “engineering with nature,” which focuses on designing coastal infrastructure that protects cities while also supporting wildlife. Instead of smooth, lifeless barriers, the goal is to create shorelines that can double as functioning ecosystems. San Francisco’s Living Seawall joins similar projects in places such as Sydney, Seattle, Vancouver, the United Kingdom, and the Netherlands, all exploring how cities can combine flood protection with healthier marine environments.
