Floods in the Czech Republic

Abstract

A number of disastrous floods in Czech Republic in the 1997– 2010 period, in which lives were lost and great material damage done, brought floods to the forefront of attention among natural extremes in this country. This paper presents the 1901–2010 flood series for the River Vltava (Moldau) – the Prague-Chuchle station; the Ohře (Eger) – Louny; the Labe (Elbe) – Děcin; the Odra (Oder) – Bohumin; and the Morava – Kroměřiž. To be included in the analysis, a flood had to fulfil Qk >= Q2, in which Qk is peak flood discharge and Q2 is the calculated peak discharge rate with a return period of two years. Flood patterns are influenced by climatic fluctuations (increase in temperatures, more-or-less stable or slightly decreasing precipitation totals), changes in land-use (increase in the area of arable land to the 1950s followed by decrease, steadily enlarging forest area, decrease in meadows and pastures) and by human interventions on the rivers (adjustment of channels, water structures – mainly reservoirs, extensively built in the 20th century). The highest decadal frequency of floods occurred in the first half of the 20th century (on the Ohře in 1911–1920, the Odra and Morava in 1931–1940, the Vltava and Labe in 1941–1950). While in Bohemia winter floods (snowmelt often accompanied by rain, ice-jams) clearly prevail, the numbers of summer floods (from heavy rain spells) increases in the River Morava catchment and clearly predominates on the River Odra. The most disastrous floods, of July 1903, August/September 1938, March 1940, July 1997 and August 2002, are described in greater detail.