Our Coastal Cities Are Under Threat
Coastal cities are central to discussions about our urban past, present and future—and they are also under intense threat from near- and longer-term climate change impacts. Designing for the future of coastal cities presents both challenges and opportunities for design innovation—from buildings and campuses to streetscapes and corridors to entire districts and cities. By implementing solutions such as resilient infrastructure, creative stormwater management strategies, ‘Sponge City’ principles and new tools and technologies, it is possible to plan urban and built environments that can accommodate rising sea levels and storm surges, and that are beautiful, habitable and promote equity.
Coastal cities are central to discussions about our urban past, present and future. In the US alone, coastal areas account for 40% of America’s population—with population density far greater than the national average. And globally, over one billion people live in low-lying coastal regions. These cities and towns are intimately connected to our seas, oceans and other watersheds—economically, culturally and socially.
They are also under unique threat as they face acute and ongoing ecosystem destruction, stark environmental pressure and the impacts of climate change. In the near-term, this presents challenges related to either too much water (with 100-year floods and storm surges now becoming an annual occurrence) or too little water (with increasingly concerning drought conditions). And on the horizon, significant sea level rise and associated flood risks will deeply affect these communities and environments.
The way we think about, plan and design for, and live in coastal cities is changing rapidly. This imperative to rethink the way we design buildings and urban spaces in coastal areas is already driving toward a new kind of building and infrastructure. Here, we examine key considerations for designing for coastal cities.
Think and Design Across Scales and Perspectives
From individual buildings and streetscapes to corridors and districts to entire masterplans, designing for coastal cities requires thinking across scales and perspectives. It also requires acknowledging the relationship between buildings and their surroundings as a living system in which the built environment, infrastructure and bodies of water work together to maximize impact and combat climate change.
At the building and campus level, this shift means radically rethinking what resilient and community-oriented infrastructure can look like in response to future coastal flooding and extreme weather events. A healthcare system on the East Coast, for example, is currently imagining its more coastal and climate-adaptive future, with a new campus design that can self-sustain for up to 96 hours, and act as a hub and resource for the community in the event of hurricane force winds and storm surges. In New Orleans, the Southeast Louisiana Veteran Healthcare System’s Replacement Medical Center—which replaces the VA Medical Center lost to Hurricane Katrina—is designed to remain fully operational without outside support for a minimum of five days during a disaster, with enough provisions and accommodations for 1,000 staff and patients.
As a streetscape, advanced stormwater management strategies can reduce the negative environmental impact of buildings and hardscape in the hydrologic cycle, mitigating polluted runoff and promoting groundwater recharge. This includes permeable paving that reduces runoff and retention pond areas that capture water slowly and release it back into the ground. Once runoff is captured, remaining hardscape can drain via vegetated swales, runnels and landscaped terraces that move water across structures and sites while creating unique moments of interest and connections to nature for people.
Lastly, at the district and neighborhood scale, embedding ‘Sponge City’ design principles like those explained above—as well as clustering development; protecting, conserving and even restoring environmental features; and incorporating water related ecosystem—emphasizes porosity and connectivity.
Further, by studying the way that humans interact with the coastal edge and considering how layers of people, landscape and mobility flow together—from walkability and bikeability corridors to public transportation and vehicles—we can design cities focused on people and the environment rather than cars. This integrative approach can be seen in the design for Tencent’s Shenzhen Headquarters Project (Net City), which collects water on campus, manages runoff and flooding, and plants mangrove trees at the shoreline’s edge. Most importantly, the headquarters prioritizes the needs of its inhabitants and the natural landscape at every step, from sensors that track environmental performance and flooding to the comprehensive transportation network that emphasizes public transit, micromobility vehicles and pedestrian access.
Designing in anticipation of rising sea levels and storm events is inspiring elegant and unexpected new forms, typologies, materials and geometries with high performance outcomes. Closer collaboration between designers, engineers and consultants can also result in new solutions, such as elevating walkways, incorporating bridges or building direct passages and public spaces with greater visual access and sweeping views. On the Tencent Shenzhen Headquarters Project, the design team worked closely with engineering consultant BuroHappold to design the new district to capture and harness sea breezes. The breezes baffle off the buildings, returning to and cooling the ground plane. This strategy, combined with additional tree canopy, results in a decrease of ambient air temperature by 10 degrees Fahrenheit during hot and humid months.
In addition, major new pieces of coastal protection infrastructure like parkland, wetland, levies and flood walls enable the introduction of new elements that are beautiful, functional and provide amenities such as recreational public space with walking and biking paths. This way of designing and planning for coastal cities offers new opportunities to expand the public realm and open greenspace while creating an attractive and accessible waterfront.
Finally, leveraging new data and technologies allows us to plan for and design around detailed information more accurately. For example, by tracking weather patterns decades into the future, or analyzing the parameters of materials (porosity, corrosiveness) and of context (wind and water capacity, temperature and humidity), parametric design tools are exponentially increasing the pace at which we can design innovative solutions for coastal cities.
The complexity of designing and planning for coastal cities requires designing with—rather than against—our natural ecology and landscape. Understanding where water comes from and where it flows provides invaluable insights and directly informs design outcomes. Planning for the future of coastal cities presents us with an opportunity for unprecedented design innovation, balancing functionality and ordinary utilitarian goals with designs that make our cities more beautiful, habitable and just.