E Excursion 1: Prague Floods

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Jan Daňhelka

Tuesday, April 25 2:55 pm – 4:30 pm

In the past, Prague has already been affected by many large-scale floods, which have always had a very significant and long-term impact on its life. From historical data, it is clear that floods were a common part of the annual Vltava river cycle. Almost every year, a spring flood came, which is associated with the melting of snow and ice and the movement of ice floes. In addition, there was at least one summer flood from persistent rains or torrents.

Of the historical floods, the catastrophic floods of 1273, 1342, 1432, 1481 and 1501 can be considered the largest. At first, these floods were measured only by the area of the flooded parts of the city or the degree of flooding of the head of “Bradáč” at the former Judith’s Bridge. The largest flood ever was recorded on February 26, 1784. The biggest modern flood was the flood of 2002. This flood was caused by long-term heavy rainfall in southern Bohemia. After heavy rains for many days, the Vltava River, which was to be kept within tolerable limits by the coordinated gradual discharge of water from the individual dams of the Vltava cascade, turned into an ever-increasing influx of water, which escaped any regulation and precise control.

Our first stop will be the Prague Clementinum. There is a meteorological station, which has been measuring regularly since 1752. However, the year 1775 is considered to be the beginning of systematic measurements. Meteorological measurements continue in Clementinum to this day, for more than 250 years.

The second stop will be “Bradáč” under Charles Bridge. This is the stone head of the mysterious Bradáč, a man with a beard. Since the Middle Ages, Praguers have been using it as a water level for large floods on the Vltava. As soon as the water touched the lower part of Bradáč’s beard, the river rose inconspicuously from the banks, and those who lived by the water received a signal to evacuate. When the water flooded Bradáč’s mouth, the river was already flowing into the waterfront streets, and if only Bradáč’s bald spot was visible, people could ride the Old Town Square in boats

We will also visit Prague’s Kampa, where there are two flood signs from 14.8.2002, in 1784 and 1845. The last stop will be the limnigraf Výtoň. It is a device used to read and record the level of the Vltava in time.