Design Principles for creating more Resilient Cities*
It will take a new set of planning and design principles to create more resilient cities, more resilient communities, and more resilient buildings. This will take a significant revision of current thinking. As a starting point we propose the following as an overarching set of principles for creating greater urban resilience:
1. Diversity: Increasing the diversity of the various systems that comprise our cities is important because with greater diversity comes an increased ability to thrive, survive and bounce back from external shocks and stresses. Diversity of systems reduces the potential negative impact to the whole city of the failure of any one particular system. Increasing the diversity of systems means that we will want to maximize the diversity of different business types, institutions, sources of food, and industries, etc.
2. Redundancy: The increasingly likelihood of more energetic weather events associated with global climate change means that cities and their communities will need to build the capacity for resilience to more frequent and powerful environmental shocks and stresses. An increased redundancy of key infrastructure systems—including electrical power, fuel supply, waste water processing and, most important, food and potable water supply - means that if one system is compromised, there is enough redundancy in the overall system to fill in for the compromised system until it can be replaced or repaired. Although redundancy reduces efficiency, it necessary increases resilience.
3. Modularity and Independence of System Components: Resilience capacity will be increased when system components have enough independence that damage or failure of one part or component of a system is designed to have a low probability of inducing failure of other similar or related components in the system.
4. Feedback Sensitivity: Feedback Sensitivity is a system’s ability to detect and respond to changes in its constituent parts. The more quickly a system can detect and respond to changes throughout the system, the greater its potential for effectively coping with these changes, and thus for resilience. Social, economic, and technical systems designed with tight feedback loops will increase resilience. In our cities, urban density is one of the important foundations for loop tightness. Density provides for reduced time and costs for moving information and materials throughout the system in an efficient and effective manner.
5. Capacity for Adaptation: Resilience capacity will be increased by the relative adaptability of the various systems that comprise a city. City systems and infrastructure that are designed to quickly adapt to changing conditions and requirements will increase the overall resilience capacity of a city.
6. Environmental Responsiveness and Integration: The resilience capacity of a city is increased by how responsive and integrated its systems and functions are with its natural systems, services and resources. Environmental responsiveness and integration will not only reduce the cost of creating and maintaining technical infrastructure, but reduce the relative probability of infrastructure suffering significant negative impacts from the increasing environmental shocks and stresses associated with climate change.
* Updated February 4, 2012