Historical changes in frequency of extreme floods in Prague

L Elleder

doi:10.5194/hess-19-4307-2015

Abstract

Abstract. This study presents a flood frequency analysis for the Vltava River catchment using a major profile in Prague. The estimates of peak discharges for the pre-instrumental period of 1118–1824 based on documentary sources were carried out using different approaches. 187 flood peak discharges derived for the pre-instrumental period augmented 150 records for the instrumental period of 1825–2013. Flood selection was based on Q10 criteria. Six flood-rich periods in total were identified for 1118–2013. Results of this study correspond with similar studies published earlier for some central European catchments, except for the period around 1750. Presented results indicate that the territory of the present Czech Republic might have experienced extreme floods in the past, comparable – with regard to peak discharge (higher than or equal to Q10) and frequency – to the flood events recorded recently.

Highlights

Research of historic floods significantly enhances our ability to better understand the behaviour of recent flood events in the context of global environmental change
The high variability in Q2 flood events most likely does not reflect the reality – rather it is a consequence of the fact that many of these “unimportant” floods were not recorded in the 12th–18th centuries
Considerable equilibrium is obvious in POTQ10 before 1500 (17 events in total, which means 4 events per century, on average), and after 1500 (55 events in total, that means 11 events per century, on average). This set is representative for the period after 1500 at least, when POTQ10 can be considered a good approximation of the real count of floods

Summary

Introduction

Research of historic floods significantly enhances our ability to better understand the behaviour of recent flood events in the context of global environmental change. In the Czech Republic, four extreme summer floods were recorded within the last 15 years (1997, 2002, 2010, and 2013). Two of these were classified as 500-year or even 1000year events (Blöschl et al, 2013; Hladný et al, 2004); two out of the four stroke the Vltava River catchment. An interesting question emerges as to whether there is an analogy with a similar frequency of important or extreme floods in the past. The aim of this contribution is to answer two scientific questions: 1. Has the territory of the present Czech Republic experienced four summer extreme flood events within a mere 15-year period earlier in history? The aim of this contribution is to answer two scientific questions: 1. Has the territory of the present Czech Republic experienced four summer extreme flood events within a mere 15-year period earlier in history?

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Conclusion