Chapter 15Flood Risk Mitigation: Design Considerations and Cost Implications for New and Existing Buildings

Rotimi Joseph, David Proverbs and Jessica Lamond

15.1 Introduction

Worldwide, flooding has been predicted to threaten up to 2 billion people or more by 2050 due to the collective effect of higher frequency and intensity of rain, snow and ice melting, which may affect more denuded slopes and high runoff urban areas, in conjunction with the projected population growth (Bogardi, 2004). During the past decade, reporting of incidents of natural disasters that meet Emergency Event Database (EMDAT) criteria have increased sixfold compared with the 1960s due mainly to an increase in small- and medium-scale disasters (Guha-Sapir et al., 2006). Blunden and Arndt (2012) and Field et al. (2012) asserted that almost 90% of natural disasters are hydro meteorological events such as droughts, storms and floods. Further, scientific evidence suggests that global climate change will only increase the number of extreme events, creating more frequent and intensified environmental emergencies (Field et al., 2012).

Currently in England and Wales, 5.2 million properties are in flood risk areas, amounting to 1 in 6 properties (Environment Agency, 2009), although many of these areas are well managed and protected by means of flood defences. There is every indication that this figure will rise further if climate change results in more frequent extreme weather events or if properties continue to ...

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