One hundred thirty-year flood in the ancient city of Prague
Engineer, Public Works Department
City of Davis, California
Immediate Past President, APWA Sacramento Chapter
Prague is the capital of the Czech Republic which is located in the heart of Europe. The history and development of Prague dates back more than eleven centuries. Today the city covers a total area of 193 square miles (496 square kilometers) with a population of about 1.2 million. Almost three million tourists from around the world come to visit Prague every year.
Prague is a municipal corporation operating under the general laws of the State and Council form of City Government. It is divided into 57 city districts and 112 land areas. It is administered by a governing body of the City of Prague. It consists of the Prague City Assembly (70 representatives elected for a four-year term of office) and the Prague City Council (11 members elected among the representatives). The Prague City Council is headed by the Mayor.
What happened during the critical days before, during and after the 130-year flood in August 2002?
In 1990 a mathematical model of potential flooding of Prague was developed and analyzed. Flood stages were identified and studied, and a thorough plan of preventive measures and implementation was developed. Among other things a detailed system of control barrier walls was designed, built and stored for future use. All of these flood control measures were later applied and used to help save the Old Town from the devastating flood of August 2002. All units of the crisis emergency management, together with the integrated rescue system (fire department, police, ambulance service, National Guard and other emergency services), were involved in the effort to save the city from this devastating flood. What helped to save much of the historic buildings in Prague was the implementation of these preventive measures.
The extremely large and intense amount of precipitation in early August 2002 was the reason why the high waters were not retained by the Vltava River's dam cascades. It is estimated that the Vltava River basin would hold roughly 35 billion cubic feet (one billion m3) of water if they were entirely empty. However, in western and southern Bohemia about 105 billion cubic feet (three billion m3) of water fell within a short period of time. Retaining the water since August 7 and managing it in the next couple of days made it possible to delay the flood onset and gain the time necessary for stopping navigation on the river, clearing the flood plains, and towing boats away into protective harbors.
On Monday, August 12, the City Crisis Committee was instructed to begin gradually implementing flood control measures as suggested in the previous 1990 flood study and flood prevention design. As early as Monday evening large parts of the City had been closed. The towing of cars and evacuation of people from neighborhoods had begun.
The assembly and erection of the flood control wall barriers was in full force (anyone interested in learning more about these flood control wall barriers and how they functioned during this critical time is welcome to attend a presentation at the 2003 APWA International Congress in August in San Diego). During the night on Tuesday, August 13, the buildings of the Prague City Hall and the City Government were at risk of flooding, and were also evacuated. The Crisis Management Center had to be relocated and was in full operation from a temporary location until August 26.
During the floods
Floodwaters were raging and one of the most unfortunate problems which attracted local and foreign media attention was the attempt to evacuate animals from the Prague Zoo. Many animals were lost during the rescue efforts.
Traffic was also significantly affected during the floods. The Vltava River divided the City into two sections. Twelve of the fifteen bridges crossing the river were closed due to flooding. The large amounts of water also caused flooding of a significant part of the Prague Metro (Subway). The Metro is the main transportation corridor and predominant mode of transportation in Prague. A total of 17 out of 28 stations were flooded and out of operation (if you would like to see a Micromedia presentation on the flooding stages of the Metro in Prague, attend the presentation at Congress). This significantly paralyzed the City's Public Transportation System. This situation was dealt with by arranging for emergency substitute surface public transportation using buses, trams and trains. The affected parts of the City were closed to all traffic, and drivers were asked not to come to Prague because of the traffic calamity. The electricity and gas supplies were also shut down in flooded areas.
Over 27,000 rescue workers (professional as well as voluntary firemen, National Guard, and policemen) were performing rescue operations. Many volunteers and other humane and civic groups helped provide labor, materials and financial help. The Czech Republic and Prague also benefited from foreign aid.
When the water level dropped, roughly on August 16, remedial actions to repair the flood damages were launched, such as pumping off water, disposing trash from flooded areas, cleanup at bridges and, most of all, evaluating the structural stability of buildings. The flood caused three large buildings in Prague to collapse and several others to suffer severe structural damage.
Situation in Prague two weeks later
Two weeks following the flood, electricity and gas supplies were being slowly restored to most parts of the city. Previously closed areas were being reopened to limited traffic. Only local residents and business owners were allowed in the area. At the time, it was estimated that large sections of the Prague Metro would be out of service from several weeks to several months. The causes of the extensive damage were being investigated.
Many schools in Prague had to begin their fall term later than usual (the usual date is September 1) due to some schools being damaged by the flooding and others being used for housing of evacuated people.
The water quality of the Vltava River continued to be a problem. This was due to the damage caused to the wastewater treatment plant by the floods. Public health authorities issued special guidelines for waste management and sewerage disposal. Thanks to early measures no epidemic broke out.
The cleanup and disposal of damaged property continues in areas affected by the flood. Some parts of the city still remain closed. Traffic congestion in downtown still persists. Special measures have been carried out on the North-South traffic corridor to provide for bus transport as a substitute for the Metro service.
The preliminary gross estimate of the damages incurred due to this flood in the whole Czech Republic is $2-$3 billion (CZK 60-90 billion). The City of Prague has suffered losses of about $330 million (CZK 10 billion).
Helena Allison can be reached at email@example.com.
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