Transforming waterfronts for a resilient and sustainable urban future

• By 2050, more than 800 million people living in 570 cities around the world could be at risk from rising sea levels, according to estimates.
• Many cities worldwide face ageing infrastructure and changing dynamics, particularly post-COVID, which pose extra challenges for many.
• Strategic redevelopment of city waterfronts can help transform underutilized spaces into thriving, resilient and sustainable communities.

By 2050, the total number of city-dwellers at risk from sea-level rise could exceed 800 million people, living in 570 cities, according to C40 Cities. At the same time, many of our cities face ageing infrastructure and changing dynamics in the wake of the COVID-19 pandemic, which has changed how people want to live, work and recreate in our urban centres.

The recent study projects that, without significant intervention, rising sea levels could result in more than $1 trillion in damages to coastal cities worldwide by mid-century. This challenge may seem overwhelming for cities already managing a range of complex issues. However, failing to act will ultimately be more costly than taking proactive measures to reduce risk.

To overcome this, we need to shift our perspective from crisis to opportunity. Cities across the world have demonstrated that strategic redevelopment can transform underutilized spaces into thriving, resilient communities. For example, many former industrial waterfronts have been revitalized into mixed-use districts that integrate flood protection with economic and social benefits.

Similarly, cities are converting outdated infrastructure, such as "ghost" airports, into hubs for innovation and green development, bringing new life to urban areas, waterfronts and coastal regions to enhance their resilience and sustainability while addressing multiple other city needs.

By rethinking traditional approaches to infrastructure and embracing integrated solutions, such as nature-based defenses, adaptive reuse and community-driven planning, we can create more liveable, sustainable urban environments that address multiple needs at once.

Infrastructure evolution - from minimize negative impacts to achieve multiple positive impacts over long term Image: Jacobs

Waterfront redevelopment to build urban resilience

Urban waterfronts are prime areas for redevelopment because they are often densely populated, economically significant and highly vulnerable to climate impacts, offering opportunities to integrate climate adaptation strategies into urban planning.

For example, the Rotterdam waterfront has focused on adapting to climate change within urban development by transforming old industrial sites and upgrading infrastructure to manage rising sea levels. By strategically investing in urban renovations, maintenance projects and adaptive design, cities can improve resilience while promoting economic growth and sustainability.

Another notable example is the San Francisco Waterfront Resilience Program. This initiative aims to defend the city from current and future flood risks due to rising sea levels and extreme storms, and focuses on adapting shoreline elevations while also strengthening the waterfront against earthquake risks. The project aims to protect critical infrastructure, rejuvenate the waterfront, improve the city's connection to the San Francisco Bay, and provide benefits such as more open space, enhanced mobility, safety and jobs.

Coastal resilience and urban waterfront resilience are closely connected. Coastal resilience focuses on protecting coastal areas from climate change impacts like sea level rise and storms. In contrast, urban waterfront resilience applies these strategies to city waterfronts, ensuring they can withstand and adapt to these changes. By improving coastal resilience, cities can create stronger, adaptable waterfronts that protect communities and infrastructure from environmental threats.

'Sponge cities' concept to manage excess water

A "sponge city" concept involves designing urban areas to naturally absorb and manage excess water through permeable surfaces and green spaces. This approach helps cities handle heavy rainfall and reduce flooding by enabling water to be absorbed into the ground rather than overwhelming drainage systems.

Key features of sponge cities include green roofs, permeable pavements, rain gardens and swales (shallow channels that capture and filter rainwater). By incorporating these elements, sponge cities can also mitigate the urban heat island effect, improve water quality and enhance urban biodiversity.

The concept has been implemented in several cities in the United States to manage stormwater and reduce flooding. For example, Seattle's South Thornton Natural Drainage System (NDS) project uses green infrastructure like rain gardens and permeable pavements to manage stormwater and improve water quality, while Philadelphia's Green City, Clean Waters programme aims to reduce stormwater pollution through green infrastructure, including installing green roofs, rain gardens and permeable pavements across the city.

New York City has also incorporated sponge city concepts into its stormwater management plans, particularly in areas prone to flooding, with projects that include bioswales (shallow landscaped channels), green roofs and permeable surfaces. These cities are leading the way in adopting sponge city techniques to create more resilient and sustainable urban environments.

Redeveloping urban waterfronts through public-private collaboration

Public-private and cross-sector collaboration offer significant opportunities to unlock the full potential of urban waterfronts through their transformation into vibrant, multi-use urban clusters that offer revenue generation in combination with public access.

For example, a major redevelopment project in Athens aims to regenerate and restore the city's coastal waterfront with a focus on sustainability and conservation. The Ellinikon project is made possible through a public-private partnership model, where the Greek government collaborated with a private real estate company to fund and execute the project.

A key feature of this ambitious project is Ellinikon Park, set to become Europe's largest coastal park. The park incorporates thousands of Mediterranean trees and plants, innovative water management systems and repurposed materials from the site's aviation history - reflecting a strong commitment to sustainability and circularity principles.

Waterfront redevelopment also opens opportunities to diversify funding streams, allowing public investment to incentivize private investment. In October 2021, Waterfront Toronto reported that approximately CAD2 billion ($1.4 billion) in public investment has triggered over CAD9.6 billion of private sector investment in the waterfront. The blending of public and private financing can significantly increase the reach of public funding sources and deliver significantly better outcomes for communities.

Nature-positive design principles for urban waterfront

Several key design principles should be followed to ensure the success of urban waterfront and coastal redevelopment projects. These principles help create vibrant, sustainable and resilient communities that can thrive for generations. By focusing on inclusivity, sustainability, resilience and distinctiveness, we can transform these areas into dynamic spaces that meet the needs of all residents and visitors.

Integrating natural elements and ecosystems into urban waterfront planning is crucial for creating nature-positive environments. This approach enhances biodiversity, improves environmental health, and fosters harmonious spaces for both people and nature. As highlighted in Jacobs' Nature Positive Handbook: Buildings and Infrastructure Design, nature-positive design is essential for urban waterfronts in the following ways:

1. Enhancing biodiversity: Incorporating green infrastructure like wetlands, urban forests and green roofs supports diverse plant and animal species, enriching the ecosystem and creating a resilient environment.

2. Improving environmental health: Natural elements such as wetlands and green spaces act as filters, improving air and water quality by trapping pollutants and sediments, leading to cleaner environments and healthier ecosystems.

3. Providing natural protection: Green infrastructure offers protection against flooding and erosion. Wetlands, urban forests and permeable surfaces absorb stormwater and reduce runoff, protecting areas from extreme weather impacts and enhancing long-term resilience.

4. Creating harmonious spaces: Integrating nature into urban planning creates spaces where people can connect with the environment. Parks, greenways and urban trails provide recreational opportunities and improve residents' quality of life, promoting better mental and physical well-being.

5. Supporting local wildlife: Green roofs, urban gardens and other nature-based solutions provide habitats for local wildlife, supporting biodiversity and local economies that rely on eco-tourism and sustainable practices.

By adopting nature-positive design principles, urban waterfronts can transition seamlessly from urban to oceanfront areas. This approach drives development that is sustainable, resilient and beneficial for both people and the planet. It addresses multiple challenges while creating vibrant, thriving communities.