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In the UK, a disparity exists between modelled future weather/climatic patterns and the assessment of climate change impact on flood risk in the UK statutory planning process. Specifically, the impacts of climate change on the physical characteristics of a river catchment (e.g. land-use change, vegetation cover, soil moisture) are not considered when generating climate change weighted design flood events to assess the potential impact of flooding on a development in the future. Instead, a UK-wide averaged perturbation factor is applied. In this paper, a method is tested to integrate climate change data from UK climate projections 2009 (UKCP09) into design flood estimation methods (ReFH) as part of the current planning process. Scenarios are developed for a single, critical duration, 1%probability (1-in-100 year) design flood event that reflects plausible changes in catchment physical parameters in the 2080s. Initial results suggest that a 1-in-100 year storm in the 2080s may be greater in magnitude, rise and recede faster, and be associated with greater depths of flooding than predicted using current flood risk assessment frameworks in the UK. This information could provide new information to help developers choose more sustainable, flood-resistant and resilient designs. IntroductionUK climate change projections provide a wealth of information about how the climate will change in the future (Murphy et al., 2009). Among many common climate variables including temperature and precipitation, the projections also include soil moisture changes, humidity variations and storm frequency. These projections are available for a range of future horizons and, in many cases, the projections are probabilistic. A number of studies have taken these data to assess the possible future impact of climate change on rainfall intensity flooding (see works by Prudhomme et al. Current flood estimation techniques generally used by planners and developers utilise empirically derived relationships captured within the Flood Estimation Handbook (FEH) (IOH, 1999) to model rainfall-runoff as a storm hydrograph (ReFH) (see Kjeldsen et al. (2007) for further information). The ReFH method is able to produce storm hydrographs for a range of return periods within a catchment. These design floods can then be used as input boundary conditions within flood models as part of the flood risk assessment process. This process in itself is known to associate lower frequency rainfall events with flood events of a specific frequency (e.g. 1 in 100 years). It also does not assess any effects of the temporal distribution of rainfall that will drive unique groundwater responses that may significantly impact the rainfall-runoff relationship, particularly for permeable catchments (Faulkner and Barber, 2009;Wheater et al., 2002).Statutory UK planning regulations such as Planning Policy Statement 25 (PPS25) (DCLG, 2006) require climate change impacts on 1-in-100 year design floods to also be accounted for as part of the flood risk assessment process within UK plann...

An integrated approach to water management and urban design has actively been sought in the development of the master plan for a major urban extension in north-west Cambridge. A multidisciplinary team of urban designers, landscape architects, engineers, ecologists and planners have developed a water-sensitive urban design strategy for the site. From the concept stage, integrated sustainable drainage measures and extensive green corridors have been integrated into the site, to treat and store surface water above ground while also supporting urban design and place-making aspirations. A site-wide strategy for water management is also being developed to utilise opportunities to integrate the entire water cycle and progress towards water neutrality, including consideration of site-wide wastewater recycling for non-potable reuse; site-wide stormwater harvesting, using sustainable urban drainage systems features to filter water for non-potable reuse; and specifications for water efficiency in buildings and the landscape. The case study demonstrates how the consideration of water management upfront can be used to shape the spatial layout, utilities and infrastructure strategies, and the urban design vision for new development.