Nasrin Alamdari, a researcher at Florida State University’s College of Engineering, is sounding a cautionary note about a widely celebrated tool in urban water management: nature-based solutions (NbS). While cities from Miami to Melbourne have embraced green roofs, permeable pavements, and constructed wetlands as eco-friendly ways to handle stormwater, Alamdari’s new study in *Frontiers in Water* (published in English as *Frontiers in Water*) suggests that these systems may not be as resilient as we assume when the climate behaves unpredictably.
The problem isn’t just heavier rainfall—it’s the sequence of extremes. A prolonged drought, for instance, can bake the soil so thoroughly that when a sudden deluge arrives, water simply sheets off instead of soaking in. “We’re seeing cases where bioretention systems designed for historical rainfall patterns are failing under back-to-back droughts followed by intense storms,” Alamdari explains. “The soil cracks, becomes hydrophobic, and the system’s infiltration capacity collapses—just when you need it most.”
It’s not just about water movement, either. Microbial communities that break down pollutants in green infrastructure are also vulnerable. Consecutive heatwaves can desiccate these microscopic workers, reducing their ability to clean water. “We’re losing the biological engine of these systems,” she says. “And once it’s gone, recovery can take months—if it happens at all.”
For the energy sector, this has real commercial implications. Urban water resilience is increasingly tied to energy resilience. Pumping, treatment, and stormwater conveyance systems all draw power. If NbS fail under climate extremes, cities may need to fall back on energy-intensive grey infrastructure—concrete tanks, mechanical separators, and pumping stations—just to maintain service levels. That could mean higher operational costs, stranded assets, and missed decarbonization targets.
Alamdari proposes a shift toward hybrid systems—combining green infrastructure with adaptive grey components—that can scale up during crises. “We need real-time monitoring of microbial health, soil moisture, and infiltration rates,” she says. “And we must design with future climate data, not past weather records.”
Cities and utilities investing in NbS today may find themselves facing an “adaptation illusion”—green infrastructure that looks sustainable on paper but fails under the very conditions it was meant to withstand. The message is clear: nature-based solutions are part of the solution, but not the whole answer. The future of urban water resilience may lie in smarter integration, not just greener infrastructure.