Can cities learn to live with water?

Last year, severe floods left cities and towns across the globe underwater, with Valencia, Dubai and Porto Alegre among the hardest hit.

Many of these disasters – along with storms, heatwaves and wildfires – have already been attributed to the climate crisis.

Flooding remains a complex challenge with no quick fix, especially in densely populated urban areas. But despite the risks, cities are continuing to expand into high-risk flood zones.

Fortunately, many cities are rethinking their relationship with water and adapting by finding ways to coexist with nature.

We’re now seeing cities worldwide transformed with floating houses, sponge cities and climate parks – showing that risks can be turned into opportunities for greater resilience. 

These innovative urban solutions are especially vital at a time when homes in parts of the U.S., Canada and Australia are becoming uninsurable, while many property owners in the Global South lack insurance altogether.

So, can cities shift their perspective and treat floods as an opportunity for innovation? What strategies can they adopt to embrace water and create resilient communities?

Here are some insights on why urban growth is expanding into flood zones and how some cities have successfully adapted – mitigating climate risks and building resilience by living with water.

Why are cities being built in flood zones?

You might expect flood-prone areas to be less populated than other areas, considering the inherent risks involved.

But in fact, the opposite is happening. Between 1985 and 2015, human settlements increasingly expanded into flood zones as urbanization picked up pace around the world, according to a study in Nature.

Using high-resolution data, the researchers found that about 11 percent of the world’s built-up areas face high to very high flood risks – meaning floodwaters could rise at least 50 cm during a once-in-a-century storm.

Sub-Saharan Africa and North America have the lowest flood exposure, while the East Asia and Pacific region is the most exposed.

Upper-middle-income countries have built the most new settlements in flood zones. This was primarily driven by China, where nearly half of new settlements were built in flood-prone areas over the 30-year period.

Higher-income countries like the U.S., Japan and the Netherlands saw slower expansion in flood zones. However, these countries had already built many high-risk settlements before 1985, and it’s worth noting that they also had the means to keep their waters at bay.

So, why are countries still building in flood zones?

It’s not that people deliberately choose to live where flooding is likely to happen. One major reason the study has identified is land scarcity. As cities expand and flood-safe areas fill up, settlements are increasingly being pushed into less desirable areas like riverbeds and floodplains.

While urbanization and economic development enable cities to expand in beneficial ways – bringing in jobs and better services – cities are often growing too quickly and without proper urban planning. 

In low-income countries, urban planners often struggle to keep up with constant change, which exacerbates the risks facing their cities.

These findings hammers home the importance of urban planning, especially in rapidly growing cities in the Global South.

That said, many lower-income countries lack sufficient data on urbanization trends, leaving their planners blindsided as their cities expand organically into hazardous areas.

Indigenous knowledge builds resilience

Floods aren’t a modern phenomenon: there are historical accounts of storm surges that claimed tens of thousands of lives as far back as the 13th century.

So, what lessons can we learn from past generations about living in harmony with water?

A 2023 paper in Urban Studies argues that Indigenous knowledge and perspectives play an important role in shaping flood policies, offering local insights that make urban planning more data-driven and place-specific.

The study examined different cities across various time periods – Ancient Rome, Dongting Lake in China, the Mississippi region in the U.S. and Brisbane in Australia – where a common pattern emerged: these societies have historically thrived by building homes, trading and farming near rivers. 

Flood mitigation policies must then be designed to account for this long-standing relationship with water. The authors emphasize that “indigenous-style perspectives are increasingly part of a more reflexive flood policy that looks towards, for example, nature-based solutions.”

One such example is a planning paradigm called espace de liberté (freedom space), which emphasizes creating corridors around waterways that are designed to flood. 

This has notably been adopted in New Zealand, where publicly accessible strips of land have been created next to many water bodies, as well as at the municipal level in Munich, Geneva and Portland.

In rapidly-growing cities, it’s important to preserve these spaces for floodwaters before they’re turned into concrete – making them much harder to protect against future floods.

The study calls for further research into flood hazards to fill data gaps, as well as on how Indigenous groups adapted to nature, often resisting the engineered solutions and protection rules imposed by colonial societies.

Gray infrastructure, green solutions

We often overlook nature-based solutions in favor of short-term, human-engineered interventions – sometimes with unintended consequences. But nature has, time and again, demonstrated better ways to help us mitigate environmental risks.

For example, the Netherlands boasts some of the world’s most advanced flood defenses, consisting of dikes, canals and sea gates, that have protected the country against floods, storm surges and sea level rise. 

The Delta Works is the largest Dutch flood engineering project, built after the devastating 1953 North Sea flood and consisting of cutting-edge dams, sluices and barriers to close off a large portion of the country from the sea.

Another is the Zuiderzee Works, which turned a hazardous sea inlet into a freshwater lake, creating new land for farming and cities.

But the Dutch approach isn’t just about building massive infrastructure projects. It’s also increasingly incorporating nature-based materials and systems.

One of the country’s latest innovations is the sand engine, which involves distributing large volumes of sand to naturally spread over time, preventing beach erosion and flooding.

Another solution is the addition of living organisms, such as mangrove forests, to existing dikes to mimic rocky coasts.

This innovative approach, known as green-gray infrastructure, blends the benefits of traditional engineering with natural systems to create smarter, more resilient climate solutions.

Rising above the flood

Across Asia, too, cities are embracing nature-based solutions to mitigate flooding, recognizing that traditional gray infrastructure has its limits, especially as climate patterns grow ever more unpredictable.

After the 2011 floods in Bangkok, which claimed hundreds of lives, the Thai capital turned to nature-based solutions to keep itself from sinking. 

These included so-called monkey cheeks – green spaces designed to capture and store more than 4 million liters of water. Inspired by the way monkeys store food for later consumption, these open spaces serve as reservoirs to help manage floodwaters.

China’s sponge cities take a similar approach by using nature to manage water. They incorporate greenery like gardens, trees and green roofs, along with permeable sidewalks that soak up rain and let it drain naturally to prevent floods.

Wealthier countries aren’t immune to climate crisis-induced flooding, either. While they have the resources to invest in large engineering projects, nature-based solutions still often prove the way to go.

Take Copenhagen, for example, which transformed Enghaveparken into a ‘climate adaptation park’ in response to the historic Danish cloudburst of 2011.

Originally built in the 1920s, the neoclassical park has been redesigned with water chambers that capture and redirect floodwaters to where they need to go – all while preserving its original charm.

Back in the Netherlands, an entire community of floating homes has been built in Amsterdam to adapt to future sea level rise. 

This incredible innovation goes beyond merely accepting the reality of living with water and dealing with floods. Instead, it embraces the challenge by finding ways to work with water rather than bending it.

After all, the future of flood-resilient cities isn’t about fighting water: it’s learning to live and thrive with it.