Spatial design integrates social, cultural, economic, and political perspectives with natural site conditions and man-made construction to plan for sustainable urban development. The current flood-risk-related challenges induced by climate change place pressure on designing cities in which both natural and man-made conditions can be imbalanced. Creating a purely engineered line of flood defense to restore this balance does not always work. The idea of living more closely with water includes the discipline of spatial design more into flood risk management than the current dominant paradigm. Following the probability approach defined as risk = probability × consequences, the current Dutch paradigm is focused on reducing the probability with dikes; the United States focuses on reduction of consequences by evacuation and recovery. This chapter focuses on urban design and planning strategies for reducing flood risk not just by a flood defense line such as a dike, but also reducing risk by means of urban development behind the dike. Integrated urban flood design must integrate site-built environment characteristics and natural systems, and simultaneously solve challenges posed by hazards. Effective design, therefore, must be conducted on the basis of hydraulic engineering knowledge, leading to spatial designs that introduce resilient urban qualities. Two cases for this approach are presented and compared: Vlissingen, the Netherlands and Galveston, Texas, United States.

Engineering for flood resilience of dense coastal regions often neglects the resultant impact on urban design quality. Vital subsurface infrastructure such as hydraulic systems, water networks, civil construction, transport, energy supply and soil systems are especially important in shaping the urban environment and integrating resilience. However, the complexity and resource intensive nature of these engineering domains make it a challenge to incorporate them into design measures. In the process of planning, this impedes proactive collaboration between the design and engineering communities. This study presents a collaborative design engineering exercise undertaken to find spatial solutions to flood-prone Edogawa ward in Tokyo, Japan. The team included urbanists, hydraulic engineers, water resource managers, and landscape architects. Hydraulic engineering solutions were combined with spatial planning methods to deliver two alternative strategies for the chosen site. Each alternative was then evaluated for its urban design quality and effectiveness in reducing flood risk. The exercise highlighted that successful design requires comprehensive interdisciplinary collaboration to arrive at a sustainable bargain between hard and soft measures