Return periods of the August 2010 heavy precipitation in northern Bohemia (Czech Republic) in the present climate and under climate change

Abstract

The study deals with estimates of return periods associated with the August 2010 heavy precipitation in northern Bohemia (Czech Republic), which resulted in flooding with enormous material damage and loss of lives, in the present climate and under climate change scenarios. We focus on the record-breaking 1-day and 2-day amounts at lower-elevation stations, exceeding 150 and 250 mm, respectively. The estimates of return periods are based on two methods of regional frequency analysis and they are compared with local (at-site) estimation. The regional methods consistently suggest that the August 2010 event was exceptional in view of past records, but the return levels decline substantially – by a factor of 2–4 – if parameters of the generalized extreme value distribution are allowed to vary in accordance with scenarios based on an ensemble of regional climate model projections for 2070–99. In spite of large uncertainty associated with future climate change scenarios, increased recurrence probability of such heavy precipitation events in the 21st century should be taken into account when designing and implementing flood risk prevention and mitigation measures.