A groundbreaking project led by the University of Portsmouth and Southern Water is attempting to reverse decades of coastal ecosystem collapse by deploying specially designed floating wetlands in degraded waters—a recognition that decades of concrete seawalls and flood defenses have come at a profound environmental cost.
The initiative addresses a stark reality: more than 85 per cent of aquatic and marine vegetation, including saltmarsh, seagrass and kelp, has been lost over the past 50 years. Rather than accept this loss as inevitable, researchers are trialling a nature-based solution designed to restore habitats in spaces where development has eliminated them entirely.
The Scale of Ecosystem Loss
Coastal environments across the UK have been fundamentally transformed by human infrastructure. The dominance of concrete seawalls and flood defences has eliminated the natural wetland systems that once provided essential ecological functions. Dr Ian Hendy from the Institute of Marine Sciences at the University of Portsmouth, who is leading the project, framed the challenge directly: "By creating a floating saltmarsh, we are reintroducing habitat into spaces where it has been completely lost to development."
This framing underscores a central reality of modern coastal management: the tension between human protection and ecological restoration. The project suggests these need not be mutually exclusive.
How the Floating Wetlands Work
The floating wetland technology uses specially designed floating rafts that effectively recreate a saltmarsh ecosystem in areas where natural marshes can no longer exist. The systems will host a diverse range of saltmarsh plants, with marine species being trialled on a floating system—a approach that has only been tested six times previously, indicating the experimental nature of this intervention.
Dr Hendy emphasized the multiple benefits: "These systems can provide refuge for marine species, improve water quality and help rebuild biodiversity in some of our most impacted coastal areas." Beyond habitat provision, the wetlands are designed to absorb nutrients and pollutants, addressing water quality degradation that often accompanies heavily modified coastal zones.
Pilot Programme and Monitoring
The wetlands have been established at the Southcoast Wake Park in Portsmouth as part of a long-term research programme. Scientists will employ a before-and-after monitoring approach to assess environmental impact, tracking changes in water quality, biodiversity and ecosystem resilience over time. This rigorous monitoring reflects the research-driven nature of the initiative and the commitment to evidence-based coastal restoration.
Joff Edevane, environment and water quality lead for Southern Water, positioned the project within a broader vision: "This is a wonderful opportunity to pilot a floating wetlands approach to improving water quality and providing Natural Capital. The vision is to use this nature-based solution in protected areas in the future."
Southern Water has indicated that if successful, the floating wetland technology could be deployed widely across the UK in both marine and freshwater environments, suggesting potential for scaling this approach beyond the pilot phase.
Researchers characterize the approach as offering a "practical, scalable solution" to the "widespread loss" of essential coastal ecosystems—a framing that acknowledges both the severity of the problem and the possibility of systemic intervention.
Why This Matters:
This project addresses a fundamental question about how societies manage the trade-offs between human infrastructure and ecological health. The loss of 85 per cent of coastal vegetation over 50 years represents a massive degradation of natural systems that provide essential services—water filtration, fish habitat, biodiversity support—that communities depend upon. Rather than accepting this loss as the permanent cost of coastal development, the floating wetlands approach suggests that restoration and innovation can work within existing constraints. The long-term monitoring programme will generate evidence about whether nature-based solutions can meaningfully rebuild ecosystem function in heavily modified environments. If successful at scale, this could reshape how local authorities and water companies approach coastal management, shifting from purely engineered solutions toward hybrid approaches that balance human protection with ecological restoration. The project also reflects a broader recognition that addressing environmental degradation requires public institutions, research partnerships, and sustained investment—not market-driven approaches alone.