Trends in Hydrological Intensification in the United Kingdom: Implications for Flood Risk Management (PAP014830)

Código

PAP014830

Autores

Nevil Wyndham Quinn

Tema

Floods in a changing climate

Resumo

A recent review suggests that despite unequivocal evidence for warming in the 20th century, evidence for any compelling, long term increase in the magnitude or frequency of fluvial flooding in the UK is sparse (Hannaford & Hall 2012). Analysis of trends is confounded by a both the relatively short data sets (mostly post -1970), and the fact initiation of measurements coincided with a relatively flood poor-period, as contrasted with a relatively flood-rich period towards the end of the available record (e.g. 1998 -2000). The consequent positive trends are therefore either partial evidence for climate variability and/or simply an artefact of the start and end of the measuring periods (Hannaford & Marsh 2008). This paper will extend earlier work based on datasets ending in 2003 or earlier, and re-examine trends in flood peak magnitude and frequency (annual maximum series and peaks over threshold) for a number of natural and developed catchments and for data to the most recent available water year. Recognising the limitations of just flood peak analysis, this paper will also apply the Richards-Baker Flashiness Index (R-B Index)(Baker et al. 2004) to gauged daily flow data, to examine the relationship between flood peaks defined by the AMS and POT data series, and any changes in the hydrological responsiveness of these catchments, extending the work of (Quinn 2010). Given that a climate change signal in flood frequency/magnitude is not expected to be detectable in observed data for many decades (Wilby 2013), the question arises whether analysis of modelled future flows can yield any further insight. This paper will therefore also apply the RBI to a number of catchments where modelled future flows are available (1950- 2098). The final part of this paper will explore the implications of this analysis for flood risk estimation and the practice of flood risk management.