Kathmandu - As climate change intensifies rainfall extremes across the globe, cities are increasingly facing a paradox: destructive floods during heavy rains and water scarcity during dry periods. Urban planners and environmental experts now argue that the problem lies not only in climate change itself, but in how modern cities have learned to treat water - as a threat to control rather than a resource to manage wisely.
A growing concept known as the “sponge landscape” approach is challenging this long-standing mindset. Instead of channeling rainwater quickly into drains and rivers, sponge landscapes are designed to slow down, absorb, filter, and reuse water, allowing territories to function more like natural ecosystems.
Cities That Forgot How to Breathe
Rapid urbanisation has sealed vast areas of soil under concrete, asphalt, and buildings. This has drastically reduced the land’s natural ability to absorb rainwater. As a result, even moderate rainfall events now lead to excessive surface runoff, soil erosion, and urban flooding.
“Each heavy rainfall has become a reminder that our cities have forgotten how to breathe,” urban ecologists note, pointing to overwhelmed drainage systems and recurring flood damage in dense settlements.
An illustration published by Géoconfluences (Alexis Pernet, 2023) offers a contrasting vision - one where water is managed across the entire landscape, from rooftops to river deltas, rather than at isolated points.
From Rooftops to River Corridors
The sponge landscape approach views every part of a territory as part of the solution. In urban areas, this includes vegetated roofs, permeable pavements, rain gardens, and green streets that allow water to infiltrate the ground rather than rush into sewers.
In peri-urban and rural zones, features such as swales, wetlands, hedgerows, agroforestry systems, and covered soils help capture stormwater, reduce erosion, and recharge groundwater. Downstream, forests, meadows, floodplains, and restored river corridors play a critical role in storing excess water during floods and releasing it gradually during dry seasons.
Together, these interconnected elements form a living, breathing system capable of reducing flood risks while enhancing water availability during droughts.
More Than Infrastructure: A Question of Solidarity
Experts emphasize that sponge landscapes are not merely technical solutions but social and territorial ones. Effective water management requires cooperation between urban and rural areas, as well as between upstream and downstream communities.
“When water moves more slowly through the landscape, benefits ripple outward,” planners explain. These benefits include cooler urban environments, healthier and more resilient soils, improved biodiversity, and reduced economic damage from extreme weather events.
This systems-based thinking is increasingly seen as essential as climate change reshapes rainfall patterns, making precipitation more intense, less predictable, and unevenly distributed.
A Growing Relevance for Cities Like Kathmandu and Beyond
For countries such as Nepal - where rapid urban expansion, fragile river systems, and climate vulnerability intersect - the sponge landscape concept holds particular relevance. Integrating water-sensitive planning into zoning laws, redevelopment projects, and local infrastructure plans could significantly improve resilience against floods and water stress.
The challenge now lies in translating this vision into action: embedding sponge landscape principles into everyday planning decisions, public investments, and community-led initiatives.
As cities search for sustainable ways to coexist with water, one lesson is becoming increasingly clear - slowing water down may be far more effective than trying to fight it.
