As the world grapples with the effects of climate change, natural disasters like flooding, and the spread of incontrollable wildfires are increasingly threatening cities and inhabitants. While architecture and urban planning cannot prevent these occurrences, they still possess strategies to minimize the damage associated with these events and help protect the citizens. Unfortunate events over the course of last year, like the earthquake that hit central Turkey and north-west Syria this February or the more recent earthquake in western Afghanistan, the flooding and dam failures in Libya, and the wildfires that devastated the city of Lahaina, Hawaii, demonstrate the urgency of implementing preventative and mitigation measures in addition to creating procedures for emergency intervention. This article explores the strategies and resources available to architects and urban planners to address these challenges in three types of natural disasters: flooding, wildfires, and earthquakes.
Flooding and Rising Sea Levels
As climate changes lead to the changing of weather patterns and to rise of sea levels, an increasing number of cities face a heightened risk of flooding, threatening not only the integrity of valuable buildings, like the case of the iconic building in San Marco square in Venice, but also to the loss of life and displacement of large numbers of residents, as seen in the record monsoon rains in Pakistan and the chain effects of Strom Danien in Libya. While architecture cannot prevent the most catastrophic floods, it can implement protective measures to reduce damage and save lives.
At the scale of urban planning, flood maps are a useful tool for evaluating the areas at risk. Traditional approaches of “pave, pipe and pump” that rely on channeling rainwater into drains and sewers have proven to be inefficient in the case of extreme weather events, leading to flooding disasters in many cities. Architects and urban planners are now exploring alternatives that rethink stormwater as a resource rather than a hazard, incorporating it into the ecosystem of the city. The direction, aligned with the concept of “Sponge cities” incorporates permeable pavements and reintroduces marshes and natural waterscapes to combat flooding while adding recreational facilities. These interventions redirect water from the sewage system to filter it directly and let it infiltrate naturally into the ground and reach the natural underground aquafers.
In the case of coastal flooding, natural buffers such as wetlands, dunes, and mangroves can absorb floodwaters. The city of Venice has introduced manmade seawalls to protect the lagoon from rising sea levels but is now facing criticism as over-reliance on the risks of the system to cut off the lagoon from the sea. Floating and amphibious structures are also emerging in an attempt to work with nature, and to use the flooding as a catalyst for a different type of urban development.
Read more: How Can Architecture Combat Flooding? 9 Practical Solutions
Wildfires
Wildfires are not among the first threats we think of when considering urban environments, but as the unfortunate events that happened this summer in Hawaii demonstrate, vegetation fires can reach cities to devastating effects. The compound effects of climate change result in higher temperatures, combined with drought conditions and higher wind speeds due to disparities between land and sea temperatures, all of which contribute to increasing the risk of wildfires. In addition to the threat of the flames, the smoke generated can travel great distances, causing respiratory and cardiovascular problems. While no urban strategy can completely prevent this occurrence, certain practices can help limit the spread of fires, reduce the risk to life and properties, and ensure a fast and efficient response from the authorities, firefighters, and residents.
The public and private entities share a responsibility to take precautions and reduce the likelihood and severity. The first measure involves mapping the areas at risk in order to better adapt the solutions. As peripheric neighborhoods usually have a lower density, they create the ‘wildland-urban interface’ (WUI), an intermediary space typically containing fire fuel, dry material such as fallen leaves. These areas can benefit from the planting of fire-resistant vegetation like low-growing high-moisture plants and hardwood trees with low sap or rising content. Prescribed burns can also remove the fire fuel, thus reducing its ability to spread.
Spatial planning and building codes can also play a role in wildfire management. Minimizing land fragmentation and low-density urban sprawl can limit the expansion of WUI areas. Monitorization of air quality is important in managing the risks, while comprehensive strategies ensure quick responses to protect the residents. To evaluate the effectiveness of different management strategies, researchers at Aalto University have developed an AI model that can accurately predict the occurrence of fires in peatlands. The model was developed in Central Kalimantan, Indonesia, where it analyzed 31 variables to accurately forecast the distribution of fires. While the current model is not suitable for early warning, it aids policy decisions and offers quantifiable data on the impact of various strategies.
Read more: It's Time for Designers to Embrace Fire as the Ecological and Cultural Force That It Is
Earthquakes
While the spread of some natural disasters can be somewhat hindered through urban strategies, that is not the case when discussing earthquakes. But, as the famous saying goes, “Earthquakes don’t kill people, collapsing buildings do,” meaning that prevention and harm-reducing measures regarding buildings and infrastructure solutions can make an impact. In the areas more prone to seismic activity, structural solutions such as retrofitting with eccentrically braced steel frames, or EBFs, can improve a building’s seismic resilience. An added advantage of these structures is the ease with which they can be evaluated after a quake.
In densely populated cities where substandard housing is common, the population is at an increased risk. Organizations like Build Change are developing solutions for retrofitting low-rise buildings by empowering homeowners to apply familiar techniques to improve their home’s resilience. The organization has developed a manual to help people evaluate and retrofit vulnerable houses to boost their seismic performance. In tropical areas, the use of bamboo has proven to enhance building resilience due to its strength and flexibility.
At an urban scale, seismic isolation techniques are recommended to protect crucial infrastructures from the effects of the earthquake. The technique was used when building the Sabiha Gökçen International Airport in Istanbul. The engineering design, led by Arup, placed the structure on pads and bearings that isolate it from the surrounding earth, so it sustains less damage. The measure is now recommended by the World Health Organization for the construction of hospitals as one of the most important institutions to remain functional in the case of a natural disaster.
Read more: Is Mass Timber a Good Choice for Seismic Zones?
In any scenario of a natural disaster, the first response is crucial in minimizing the number of victims and providing aid to the survivors. Architects have a role to play, especially in offering fast, efficient, and comfortable solutions for emergency accommodation. One of the architects deeply involved in humanitarian works is Shigeru Ban, who works through the foundation Voluntary Architects Network to create quick and easy-to-implement solutions to provide shelters for the victims of disasters across the world. He uses locally available and recyclable materials such as paper, cardboard, and beer crates to build shelters, schools, and churches with the help of volunteers.
