The changing climate has an effect on the quality of life in our cities: heavier rainfall (resulting infloodings), longer periods of drought, reduced air and water quality and increasing temperatures incities (heat stress). Awareness about these changes among various stakeholders is of greatimportance. Every Dutch region is required to perform a stresstest indicating the effects of climatechange (o.a. flooding and heatstress) before 2020. The level of execution, area size and level ofparticipation of stakeholders, has intentionally been made flexible.To provide more insight into the approaches and best management practices to climate resilience,this article provides 3 examples of stresstests performed on several levels: single object real estatelevel, city level and national district level. The method ‘stresstestíng’, involves flood and heatstressmodeling, defines the current status of climate adaptation characteristics of an object, city or district.The stresstest form the base line and starting point for the national 3 step approach adaptationstrategy ‘analyse, ambition and action’.The 3 pilots have been evaluated as ‘successful’ by stakeholders and yielded a significant amount ofvaluable information, further improvement is recommended as increasing the participation of theprivate sector, in a ‘quadruple helix approach’. The learning points from these 3 examples ofstresstests will subsequently be implemented in the form of improved stresstesting in the nearfuture in (inter)national cities around the world.
Due to climate change the frequency of extreme precipitation increases. To reduce the risk of damage by flooding, municipalities will need to retrofit urban areas in a climate-resilient way. To justify this investment, they need insight in possibilities and costs of climate-resilient urban street designs. This chapter focused on how to retrofit characteristic (Dutch) typologies of urban residential areas. For ten cases alternative street layouts were designed with a determination of the life cycle costs and benefits. All designs are resilient to extreme rain events. The results show that most flat urban typologies can easily be retrofitted in a climate-resilient way without additional costs compared to the standard way of retrofitting. Climate proofing sloping areas are highly dependent on the situation downstream. When there is no space downstream to divert the water into waterways or parks, costs to provide storage easily rise above traditional levels for retrofitting. In addition to reducing flood risk, for each case one variant includes resilience to extreme heat events making use of green. The life cycle costs and benefits of the green variants showed that especially green designs in high-density urban areas result in a better value for money.
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Bergen city centre is prone to both subsidence and flooding. With a predicted increase in precipitation due to climate change, a higher proportion of rainfall becomes surface runoff, which results in increased peak flood discharges. In addition, it has been predicted that sea-level rise and increasing storm surges will result in coastal flooding. In this study, the dual hazards of flooding and subsidence are analysed to exemplify possible risk assessment maps for areas most prone to the combination of both. Risk assessment maps are a support tool to identify areas where mitigation of subsidence and adaptation for surface water management will be most efficient and measures can be implemented. The results show that dual hazard assessment, like that described in this paper, can be a useful tool for decision-makers when prioritizing areas to implement measures such as Sustainable Urban Drainage Systems.
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Climate change is increasing the challenges for water management worldwide. Extreme weather conditions, such as droughts and heavy rainfall, are increasingly limiting the availability of water, especially for agriculture. Nature-Based Solutions (NBS) offer potential solutions. They help to collect and infiltrate rainwater and thus play an important role in climate adaptation.Green infrastructure, such as rain gardens (sunken plant beds) and wadis (sunken grass fields for temporary storage of rainwater), help to restore the urban water balance. They reduce rainwater runoff, stabilize groundwater levels and solve problems with soil moisture and temperature. Despite these advantages, there is still much ignorance in practice about the possibilities of NBS. To remedy this, freely accessible knowledge modules are being developed that can help governments and future employees to better understand the application of these solutions. This research, called GINA (Green Infrastructure in Urban Areas), aims to create more sustainable and climate-resilient cities by developing and sharing knowledge about NBS, and supports local governments and students in effectively deploying these green infrastructures.
INXCES will use and enhance innovative 3D terrain analysis and visualization technology coupled with state-of-the-art satellite remote sensing to develop cost-effective risk assessment tools for urban flooding, aquifer recharge, ground stability and subsidence. INXCES will develop quick scan tools that will help decision makers and other actors to improve the understanding of urban and peri-urban terrains and identify options for cost effective implementation of water management solutions that reduce the negative impacts of extreme events, maximize beneficial uses of rainwater and stormwater for small to intermediate events and provide long-term resilience in light of future climate changes. The INXCES approach optimizes the multiple benefits of urban ecosystems, thereby stimulating widespread implementation of nature-based solutions on the urban catchment scale.INXCES will develop new innovative technological methods for risk assessment and mitigation of extreme hydroclimatic events and optimization of urban water-dependent ecosystem services at the catchment level, for a spectrum of rainfall events. It is widely acknowledged that extreme events such as floods and droughts are an increasing challenge, particularly in urban areas. The frequency and intensity of floods and droughts pose challenges for economic and social development, negatively affecting the quality of life of urban populations. Prevention and mitigation of the consequences of hydroclimatic extreme events are dependent on the time scale. Floods are typically a consequence of intense rainfall events with short duration. In relation to prolonged droughts however, a much slower timescale needs to be considered, connected to groundwater level reductions, desiccation and negative consequences for growing conditions and potential ground – and building stability.INXCES will take a holistic spatial and temporal approach to the urban water balance at a catchment scale and perform technical-scientific research to assess, mitigate and build resilience in cities against extreme hydroclimatic events with nature-based solutions.INXCES will use and enhance innovative 3D terrain analysis and visualization technology coupled with state-of-the-art satellite remote sensing to develop cost-effective risk assessment tools for urban flooding, aquifer recharge, ground stability and subsidence. INXCES will develop quick scan tools that will help decision makers and other actors to improve the understanding of urban and peri-urban terrains and identify options for cost effective implementation of water management solutions that reduce the negative impacts of extreme events, maximize beneficial uses of rainwater and stormwater for small to intermediate events and provide long-term resilience in light of future climate changes. The INXCES approach optimizes the multiple benefits of urban ecosystems, thereby stimulating widespread implementation of nature-based solutions on the urban catchment scale.
