Mobile Flood Protection of the Capital City of Prague

The foundation of EKO-SYSTEM Ltd. is closely associated with the flood protection of the Capital City of Prague. EKO-SYSTEM was one of the candidates and thanks to a new and modern concept of solution and a favourable price, it succeeded in the tender and gained a contract. The division of flood protection stages in the Capital City of Prague is as follows:

     1st stage – Old Town – Josefov
     2nd stage – Lesser Town – Kampa
     3rd stage - Karlín – Libeň
     4th stage - Holešovice – Stromovka
     5th stage - Výtoň – Podolí – Smíchov
     6th stage - Zbraslav – Radotín – Velká Chuchle
     7th stage - Troja
 

1st stage   Old Town – Josefov

The work concerning this stage began in the spring of 1999 and it was finished and handed over in June 2000. The whole stage was divided into three separate sections. The first section includes the Masaryk Embankment with the barrier length of 202 meters and the barrier height ranging from 0.21 to 0.86 meters. It stretches from the Žofín Island to the building of the National Theatre and contains the stop logs with the profile of 50/215 millimeters. The second section includes the Smetana Embankment, where the barrier length is 265 meters and the barrier height ranges from 0.21 to 2.8 meters. The stop logs with the profile of 50/215 and 90/165 millimeters are used here. This section also includes the passage to the Divadelní Street with the barrier length of 6 meters and the barrier height of 5.5 meters and six passages of the Karlovy Lázně house. Their total length is 22 meters and their height ranges from 1.31 to 2.8 meters. The profile of the stop logs in both parts is 90/165 millimeters. The third section is in the Dvořák Embankment that is better known as Na Františku. The length of this section is 310 meters. The height and the type of the stop logs used is the same as in the Masaryk Embankment. The first stage can also involve the flood protection of the Four Seasons Hotel on the Mikoláš Aleš Waterfront. Its investor was not the Prague municipality but the hotel management. Therefore, it was not included in the official part of the first stage project. Nevertheless, the current user is the Capital City of Prague. The length of the barrier in this section is 127 meters and the height ranges from 0.3 to 4.35 meters.
During the flood in August 2002, this section was already finished. The general public was not familiar with the existence of this section of flood protection at that time. It was quite a surprise for many people that it suddenly appeared and protected the entire area of the Old Town from flooding. The press and the people of Prague named it “the wall of hope”. Even if there had been some discussions on the sense of flood measures before, their construction was now approved and it became a number one priority for the Prague municipality. It was acknowledged that the costs of their construction are much lower than the damage caused by flooding. In the following years, namely from 2003 to 2006, the second, third, fourth and fifth stage that provide the protection of the Prague main parts from Smíchov to Holešovice were implemented practically simultaneously. In the years from 2008 to 2010, the sixth and seventh stage that include the Zbraslav, Radotín a Troja outskirts were finished. The only section that remains unfinished is therefore Velká Chuchle that should be finished in 2012.

2nd stage   Lesser Town – Kampa

The work should initially begin immediately after the end of the first stage. Unfortunately, the negative attitude of the conservationists to project proposals delayed the construction of the first small part (the part without the “conflict”) to spring 2002. It thus happened that at the time of the flood the Lesser Town and Kampa contained no water protection and were fully flooded. The damages were substantial and exceeded the planned costs of protection by many times….
The stage was territorially divided into two main parts: from the Charles Bridge downstream to the Mánes Bridge and from the Charles Bridge upstream to the Bridge of Legions.
The first part includes the section from the Charles Bridge to Čertovka, the closure of Čertovka and then the protection of Herget´s Brick Yard and Lužice Seminary up to the Mánes Bridge. The total length of the barrier is 470 meters and its height ranges from 1.35 to 3.3 meters. Special attention should be paid to the closure of Čertovka that consists of a sliding gate with the length of 22 meters, the height of 6 meters and the weight of 45 tons that moves by means of rails. It contains permanently installed stop logs with the height of 3 meters that can be mechanically moved if necessary to raise the barrier to the total height of 9 meters. For operational reasons, the gate must be closed on reaching one-year water, and therefore it is quite often active.
The second line runs from the Charles Bridge, along the waterfront and to the Liechtenstein Palace. It is built to hold the so called fifty-year water. However, if the flood is bigger than the so called fifty-year flood, the water spills over and floods the buildings standing between the waterfront of Vltava and the Kampa Square. This square contains the second barrier line that runs towards the Liechtenstein Palace, where the two lines meet and continues around Sova´s Mills up to the wall of kindergarten. The barrier then continues as the separate protection of the building of the Fishing Union and of the Říční Street. The total length of this barrier is 589 meters and its height ranges from 1.31 to 3.8 meters. In the whole second stage, the stop logs with the profile of 90/165 millimeters are solely used.
The construction of the second stage lasted from 2002 to the middle of 2005.

3rd stage   Karlín – Libeň

This stage that was built from 2004 to 2006 consists of several separate sections. The longest one is the Ludvík Svoboda Waterfront with the length of 416 meters and the barrier profile of 50/215 millimeters. On the Rohan´s Waterfront the flood protection consists of a solid concrete wall that contains several passages with a mobile barrier. In Libeň Docks there are two lines of mobile barriers with the total length of 70 meters and the barrier height ranging from 2.15 to 5 meters. This stage further includes two parts of barriers with a total length of 44 meters in front of the Faculty of Mathematics and Physics premises of the Charles University. Their height ranges from 2.8 to 3.87 meters.

4th stage   Holešovice and Stromovka

It is the largest stage from the point of view of barrier length as well as barrier surface. It is located on the left bank of the Vltava River and stretches from the Hlávka Bridge up to the Barikádníků Bridge in the almost continuous length of more than 2.5 kilometers. The total barrier surface is 5.307 square meters. It consists of the following sections:

• The Embankment of Captain Jaroš with the barrier length of 301 meters that encompasses the Negrelli Viaduct from both sides. The barrier height ranges from 0.33 to 2.85 meters.
• This part is connected with the Bubenské Embankment section that is located in front of the well-known Holešovice Market. The pattern of this section is peculiar because it was created by the additional raising of the barrier. The first part of the construction was carried out from 2001 to 2002 as part of the improvements in front of the market. It consisted of a wall with a railing. During the flood in August 2002, it turned out that the flood level exceeded the barrier level by one meter. A solution was adopted to additionally reinforce the foundations and raise the barrier so that the entire wall did not have to be torn down and built again. The result was a structure with short and long stop logs and portable shores placed on the additionally modified pillars of the bulkhead. The total length of the section is 541 meters and the barrier height ranges from 0.5 to 2.1 meters.
• The Bubenské Embankment section is immediately tied up with the part called Nová Jankovcova. It stretches from the Bubenské Embankment up to the Lighthouse building that forms part of the flood protection. From this building the barrier line goes up to the Libeň Bridge to which the barrier is connected. The total length of the section is 688 meters and the barrier height ranges from 1.32 to 3.5 meters.
• The next section that is called the Holešovice Docks goes from the Libeň Bridge in the form of a concrete wall that changes into a mobile barrier near the building of the State Navigation Authority and then continues (placed on the embankment wall of the port with the length of 454 meters) to the “Za elektrárnou” area. The barrier height ranges from 2.15 to 3.8 meters.
• The “Za elektrárnou” section is the highest continuous section of the whole flood protection in Prague. Its length is 478 meters and its height ranges from 2.15 to 3.96 meters. Part of the flood protection consists of a wall with the height of 4 meters that is interrupted by mobile barrier passages.
• A separate section of this stage is a barrier of two railway underpasses in Stromovka. Their height is 5.15 and 5.45 meters and their total length is 23 meters. The massive portable shores with the weight of more than 500 kilograms bear against the upper part of the underpasses. Their installation requires the use of a crane and the placing of stop logs requires the use of a high-lift platform.

The stage was finished and put into use in 2006.

5th stage   Výtoň, Podolí and Smíchov

In this area, there are original high embankment walls to which mobile barriers were added as part of this stage. Therefore, a complex of twelve small objects with a total length of 339 meters and barrier height ranging from 0.43 to 3.3 meters was created. The exceptions are longer stretches near the railway bridge in Smíchov and the ING PPS company (with the length of 71 meters), near the Hořejší Embankment (with the length of 100 meters) and the Janáček Embankment (with the length of 63.5 meters). The construction took place from 2003 to 2005.

6th stage   Zbraslav, Radotín, Velká Chuchle

The stage consists of five separate parts that are further divided into individual objects. The construction of the first parts took place from 2008 to 2010. The downstream parts are:

• Zbraslav – South that starts near the stone quarry and leads up to the Peace Race Bridge. It consists of two mobile barrier lines passing through the road and going along it. Their length is 208 meters and their height ranges from 1 to 2.64 meters. The remaining part consists of a concrete wall with the height of more than 2.5 meters that is interrupted by mobile barrier passages in ten places. The total length of the barriers is 257.5 meters. With the barrier height ranging from 1 to 6 meters, the total surface of the barriers in this part is 471.5 square meters. At the same time, the concrete flood wall serves as a noise barrier that separates the residential area from the road running along the Vltava River.
• Zbraslav – North bears a similarity to the southern part. It also consists of a concrete wall that is interrupted by passages and goes from the Peace Race Bridge downstream up to the end of the Zbraslav territory. Two longer barrier lines and eight different passages with the total length of 114 meters and the barrier height ranging from 1.32 to 3.15 meters have the total surface of 239 square meters.
• Radotín is the only part of flood protection that protects part of Prague not against the flooding of the Vltava River, but against the flooding of the Berounka River. During the construction, this area was divided into the protection including the Výpadová Street and the protection going from the Výpadová Street towards the railway line. The protection is again a combination of solid concrete walls and mobile barriers. Their total length is 437.5 meters and the barrier height ranges from 1.07 to 3.3 meters. The total barrier surface is 864 square meters.
• Velká Chuchle is the last part that has not been implemented so far. The preliminary work is currently being done and this stage should be finished in 2012.

7th stage   Troja

This stage also involves two separate parts. The first part includes three passages across the Povltavská Street, the second part includes the Pod Havránkou Street that is divided into three objects as well. One of them is 6.27 meters high and its length is 15.2 meters, which makes it the largest mobile barrier in the world. Its construction requires the use of heavy machinery, namely a crane truck to raise the portable shores and supports and a high-lift platform to mount the stop logs. The construction requires seven pieces of portable shores with the height of 6.2 meters and the weight of 770 kilograms and 304 pieces of stop logs that together create the surface of 95 square meters. The total length of barriers in Troja is 285.5 meters, the height ranges from 0.33 to 6.27 meters and the total barrier surface is 616 square meters. This stage was finished in 2010.