Could Prague handle a thousand-year flood like it did 20 years ago? It is better prepared, but the system has its weaknesses
When you head along the cycle path leading from Prague’s Karlín towards Libni, you may not even realize that you are riding along the ridge of the anti-flood embankment. It stretches along the district and belongs to the whole system of a more or less noticeable flood protection system in Prague, which the locals probably rarely notice – until they need it. It would take about four hours to go all the way around it, as it is over 19 kilometers in total.
The system consists of various protective earth dams or also solid concrete walls to protect the river from overflowing its banks when it gains strength. According to Aleš Havlík from the Department of Hydraulics and Hydrology at CTU, the ideal situation is when the bed of the Vltava River has such a capacity that it can absorb and transfer the flow even in an extreme flood situation.
But this is not possible everywhere. Especially in the historic center of Prague, some streets are so close to the river that there is no space to raise the bank and other elements have to come in – especially various mobile flood defenses, which are prepared at the right time. They make up roughly a third (almost 6.9 kilometers) of the total length of the flood protection. “The height of mobile hedges ranges from 0.2 to 6.27 meters,” explains Tadeáš Provazník from the press department of the Prague municipality.
Time to build barriers
So what would happen if great water rushed to Prague again? First of all, it would be good to know about the risk at least two days in advance, according to Aleš Havlík, the Vltava cascade could also be used to mitigate the flood. However, it is important to have such a forecast so that the anti-flood defenses can be delivered to place and place.
They are stored in Dubča – a district on the south-eastern edge of Prague, where they lie in large shipping containers on the grounds of the Capital City Services Administration. On the site of the former state estate lie the described containers, which always contain a part for the construction of a specific section.
Then all that remains is to transport the plates correctly and plant them in the attachments that the firemen or soldiers will push out of the ground. After all, an attentive pedestrian can also notice metal strips embedded in sidewalks or roads in many places in Prague. The correct construction of barriers is key to water retention, so it must be practiced regularly.
“The last flood prevention exercise directly on the Vltava was held at the end of 2019, then due to the coronavirus pandemic, only an exercise was held directly on the premises in Dubč in October last year,” explains Tadeáš Provazník from the municipality.
An interesting flood protection solution can be found, for example, in Kampa, where it was necessary to figure out how to preserve the flooding of Malá Strana by backfilling the Vltava channel Čertovka. “It’s resolved