Policy research working paper 5648:
This paper is concerned with urban flooding, from the regular seasonal swell of a river through intense rainfall flash flooding, groundwater flooding, coastal storms, and coastal erosion and subsidence, and the negative impacts that large and small flood events have on the populations of cities and towns. It critically examines the changes in hazard, exposure and vulnerability of urban settlements with a view of identifying the underlying causes of any increases in flood impacts and trends which may influence future flood risk. The paper then goes on to present an overview of methods which can be employed to decrease hazard, reduce exposure and increase resilience and/or decrease vulnerability of exposed receptors.
The paper contains three main sections, followed by initial policy conclusions: (i) statistics for past trends in flood impacts and future projections of impact drivers are assessed to determine whether urban flooding has been increasing and whether it is likely to continue to do so; (ii) examines the underlying causes of flood impacts, hazard, exposure and vulnerability, to establish what is driving their growth; (iii) contains an overview of management options which may be useful in tackling the various underlying factors causing growth in flood impacts. It summarizes these interventions in terms of appropriateness for types and scales of flooding, and discusses the issues around selection and implementation of flood risk management solutions.