Flood trends in Europe: are changes in small and big floods different?

• DOI: 10.5194/hess-24-1805-2020
• Publication Date: 2020-04-09T14:50:20Z
• Authors: Miriam Bertola; Alberto Viglione; David Lun; Julia Hall; Günter Blöschl
• Keywords: Gumbel distribution; Return period; Flood forecasting

Abstract. Recent studies have revealed evidence of trends in the median or mean flood discharge Europe over last 5 decades, with clear and coherent regional patterns. The aim this study is to assess whether discharges also occurred for larger return periods, accounting effect catchment scale. We analyse 2370 records, selected from a newly available pan-European database, record length at least 40 years period 1960–2010 contributing area ranging 100 000 km2. To estimate trends, we use non-stationary frequency approach consisting Gumbel distribution, whose growth factor can vary time different strengths sizes. A Bayesian Markov chain Monte Carlo (MCMC) used parameter estimation. quantify (and related sample uncertainties), floods periods areas, across three regions where been identified previous studies. Results show that northwestern magnitude are generally positive. In small catchments (up km2), 100-year increases more than flood, while opposite observed medium large catchments, even some negative appear, especially France. southern negative. decreases less and, compared catchments. eastern do not depend on period, but plays substantial role: catchment, trend.