Creating water robust urban environments in the Netherlands: linking spatial planning, design and asset management using a three-step approach F.H.M. van de Ven 1,2 , B. Gersonius 3 , R. de Graaf 1 , E. Luijendijk 4 and C. Zevenbergen 3 1 Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, The Netherlands 2 Deltares, Urban Water Management, Utrecht, The Netherlands 3 Department of Water Engineering, UNESCO-IHE Institute for Water Education, Delft, The Netherlands 4 Grontmij Nederland bv, Houten, The Netherlands Correspondence F.H.M. van de Ven, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, Delft, 2628 CN, The Netherlands Email: f.h.m.vandeven@tudelft.nl DOI: 10.1111/j.1753-318X.2011.01109.x Key words Climate impacts; integrated assessment framework; vulnerability; water robust cities. Abstract Changes in climate will likely have major implications for the layout of cities, buildings and residents. A three-step approach is presented to respond to these changes. The approach is applied to steer expansion and redevelopment towards water robust urban environments through integrated planning and action at local level. The three steps are (1) vulnerability analysis, (2) selection of a strategy to reduce vulnerability and (3) selection of an appropriate set of meas- ures. This approach leaves much freedom to parties involved in specific urban (re)development projects. Local conditions to a large extent determine what can be done. It is up to these stakeholders to select a vulnerability reduction strategy that fits local conditions and preferences. An appropriate set of measures pro- vides a level of robustness that is acceptable for all stakeholders and that stake- holders are willing to pay for. Creating a water robust urban environment requires continuous attention of many individuals and organisations, often including the residents. The three-step approach is to be applied three times during an urban development or rehabilitation project; during (1) the planning phase, (2) the development and design phase and (3) at the occasion of the transfer from building phase to maintenance phase. Introduction Since 2007, the proportion of people living in cities exceeds the rural population on a global scale (UNFPA, 2007). More than 200 000 people move to cities every day; the urban population is expected to grow over 4 billion in the next 30–35 years (UNFPA, 2007). This urban expansion amplifies the urban heat island (Oke, 1982), which causes an increase in local temperature, but also induces more drought stress and more destructive rainstorms (Salcedo Rahola et al., 2008). A significant part of the urban population lives in flood-prone areas. This includes both coastal zones and river plains exposed to coastal of fluvial flooding risks, and low- lands sensitive to flooding from heavy rainfall or from groundwater. Droughts cause shortages in water supply for people, animals and vegetation. And dry vegetation brings another, often underestimated risk to the urban fringe: forest fires already destroyed numerous houses lushly located in semiforested areas at city boundaries (Harris et al., 2008). All these effects of urbanisation on the water system can disrupt urban functions and threaten our quality of life. Climate change aggravates all these risks. More extreme weather conditions are expected to occur more frequently in many parts of the world, thus increasing the risk of damage to residents, economy, ecology and cultural heritage (Colette, 2007; Prasad et al., 2009). Climate change will, in many cities, result in more extreme flooding (Kron, 2005), more severe droughts and more frequent and more extreme heat waves – bringing extra water demand for irrigation and cooling. And these natural hazards are expected to be increasingly more devastating (Rosegrant et al., 2002). In many coastal regions, the risk of flooding is aggravated by sea level rise and land subsidence (World Bank, 2010). Land subsidence is stimulated by groundwater extractions that are often required to avoid water shortages. Heat stress is to some extent a drought problem because availability of more water would allow for more evaporative cooling. As drought can be as detrimental as flooding, there is a need to reduce J Flood Risk Management 4 (2011) 273–280 © 2011 Climate changes Spatial Planning Journal of Flood Risk Management © 2011 The Chartered Institution of Water and Environmental Management