130 years ago, the turbulent Vltava flooded almost a third of Prague and destroyed Charles Bridge – ČT24 – Czech Television
Flood in 2002
Over the next more than a hundred years, ie the entire 20th century, a living disaster of such magnitude did not occur in Bohemia and Prague on the Vltava (the largest with a flow rate of 3240 cubic meters per second was in March 1940). Although the above-mentioned Vltava cascade protected Prague from several floods, it was not enough for such a mass of water that spilled in August 2002.
Historically, the largest flood to date has culminated in Prague at a flow rate of 5,160 cubic meters per second. The cause and development was very similar to that of 1890. There were no big differences even in the extent of flooded places, although at that time the flow of the Vltava underwent many changes by regulation.
In 2002, the water caused incalculable damage to the city’s monuments and cultural wealth, but Charles Bridge remained the same as it did after the repair 130 years ago. This was also due to the fact that excavators were standing on the bridge, breaking up debris that could clog the riverbed. The Old Town was again protected from water by flood defenses.
After being repaired at the end of the 19th century, the pillars are firmly connected to the rock
The collapse of parts of Charles Bridge in 1890 was compared to the fire of the National Theater in the period press. The circumstances caused the damaged parts to be taken into account as soon as the large water receded, and plans to repair the damage began to emerge. Three arches had to be replaced, there was more of a solution.
The most daring project was submitted by J. Kruis, according to which three arches were to be replaced by two, in order to improve the flow profile of the river. This bridge was then to be made using the latest technologies, especially concrete, which, however, caused – from a historical point of view – irreversible damage to the bridge.
A compromise was reached in the case of disputes over the tiling material used. And to better withstand water, the arches have been narrowed and there are new cavities in them.
According to its former administrator Jan Zemánek, Charles Bridge can already withstand any great water. In the past, water could get under the bridge piers, but since the restoration after the flood of 1890, the pillars are firmly connected to the rock. According to Zemánka, they are so massive that the water cannot damage them. Before that, the water was ground, as the bridge was founded only 2.2 meters below the bottom. Why it was so shallow, historians do not know.
Modern flood protection of Prague
Flood protection of the city center began in 1998. Protective elements were completed in 2000. Two years later, Prague was hit by the largest flood to date, with a level of 782 centimeters and a flow rate of 5,160 cubic meters per second. The water in the center seeped under the lower structures of the anti-flood measures and raised the paving, so sand bags had to be placed. The water almost spilled over them.
The city then changed the plans for flood control measures in other places, but did not modify them in the Old Town and Josefov.
During the next major flood of 2013, new mobile barriers, which arose as part of the construction of massive flood control measures after 2002, already protected a large part of the city. In addition to them, rubber bags filled with water, dikes made of soil or flood walls made of reinforced concrete are used in some places. Elsewhere, dry polders are used to alleviate the flood wave. However, some areas, such as Lahovice and Lahovičky, remain unprotected.
According to experts, the probability of the recurrence of extreme floods, which the Czech Republic experienced in September 1890 or August 2002, cannot be seriously determined. However, cases where large floods recurred in a few years in a row are known in the Vltava basin. The summer floods also came, for example, in 1872, 1888, 1897 and 1899, according to a study by the Czech Hydrometeorological Institute.