The absorbent city: urban form and flood risk management

Cities have always been built in hostile and harsh environments. Technological advances have helped increase the safety and security of their inhabitants and, to a large extent, have divorced the urban area from local environmental constraints. However, the dominance of economic issues in the development of urban form has created a legacy of exposure and vulnerability to flood risk, and a growing recognition of the limitations of this methodology has led to a desire to manage flooding in a way more in harmony with nature. This paper contends that, with regard to flood risk management, there has been a transition from self-protection to engineered defence to the current ideology of natural management, which provides a driver for consideration of the nature of an idealised urban form that is more resilient to flood risk, designed to absorb water and minimise damage. The paper identifies reflexivity, knowledge and adaptation as the three underlying principles of a theoretical ‘absorbent city’ and aims to stimulate debate by describing the potential urban form of a flood-resilient urban area, according to geographical and climatic constraints. Adaptive measures needed to help increase resilience are also discussed.