Water has been flowing from Želivka to Prague through a 52 kilometer long tunnel for half a century
With a maximum projected peak output of seven m3/s of drinking water and a current output of around three m3/s of drinking water, the Želivka water treatment plant ranks among the largest water treatment plants in Europe and is the largest water treatment plant in the Czech Republic. The Želivka water treatment plant, which will be called Voda Želivka from 2021, as and which has undergone extensive modernization in recent years, has produced almost five billion cubic meters of drinking water in its half century of existence. Water is fed into the treatment from the Švihov water reservoir and continues from there to the reservoir in Jesenice. The share of Želivka in supplying Prague with drinking water is around 74 percent. In addition to Prague, Central Bohemia and people in Vysočina also take water from Želivka. Prague also receives part of its water from the Káraný water source. 50 years ago, on February 1, 1973, regular deliveries of drinking water from the Švihov waterworks to Prague began.
The Želivka water treatment plant was put into operation in May 1972. The water used for the treatment comes from the Švihov reservoir, which has a volume of 266.5 million m3 of water. From the treatment plant near the Švihov reservoir, the water flows by gravity through an tunnel feeder, which is almost 52 kilometers long and ends in Jesenice near Prague. The Želivka tunnel, which was excavated using the mining method, is, according to some sources, the fourth longest water tunnel in Europe and the 15th in the world.
The basic water treatment technology is coagulation filtration with aluminum sulfate dosing. Drinking water is health-safe with ozone and chlorine.
In the past, the construction of the dam was mainly forced by the imminent shortage of drinking water in the growing Prague agglomeration. The relatively remote Želivka River was chosen because it offered the cleanest water available for its relatively easiest conservation options. It flows through a relatively sparsely populated area with little industrial load.
The construction of a large-scale source of drinking water was started in the mid-1960s. The more than 58-meter-high bulk dam was completed after ten years in 1975. The crown of the dam, which rose approximately four kilometers before the mouth of the Želivka to Sázava near Zruč nad Sázavou, is 860 meters long. The construction includes, among other things, a reinforced concrete combined building consisting of two sampling towers and a safety shaft overflow, and a water treatment plant with a sedimentation tank with a 25-meter high dam.
After the dam was filled, a lake with an area of approximately 1,600 hectares (flooded area) and a total volume of 266 million m3 of water was created. The levee on Želivka is 38 km from the dam and takes up roughly two-fifths of the river’s flow. The circumference of the reservoir is approximately 150 kilometers at maximum level. The reservoir holds water from the entire Želivka basin, which is 1178 km2. According to the volume of water in the storage area and the amount taken, it is the largest water reservoir not only in the Czech Republic, but also in Central Europe.
A big problem for the designers was the transportation of water to Prague. After a series of disputes, the pressure tunnel feeder project won. he rejected as a very expensive worker the support of his condition already because that is why he could originally use the experienced uranium industry, they could not mine the ore due to their health. 52 kilometers ends in a long tunnel or tunnel with a clear diameter of 260 cm. It starts at the water treatment plant in Nesměřice near the dam and near Jesenice near Prague. It also leads under the beds of the rivers Sázava and Blanice.
The construction of the water source required a number of other accompanying buildings. Thanks to the capture of runoff, two water reservoirs were built on the tributaries (Trnávka, Němčice) and the dam at Želivka near Sedlice in Pelhřimovsk was repaired. 35 km of new roads were built, including a bridge over the dam, hundreds of km of water pipes and a number of other water management structures.
The construction of this gigantic work significantly affected the lives of local residents and the landscape. The historic towns of Dolní and Horní Kralovice, Zahrádka and several smaller settlements (Švihov) disappeared from the map, almost 900 buildings were demolished, including a castle, a church and a railway station. “New” Dolní Kralovice in the cadastre of the nearby village of Vraždovy Lhotice and apartments in the surrounding towns were built for the residents of the flooded villages. About seven hundred hectares of cleared forests were mostly compensated by new plantings.
The dam affected not only the lives of the people from the flooded houses, but also many people in the surrounding area. Because of the strict protection zones, the area cannot be used for recreation (entry is prohibited in the first zone) and business opportunities are also hampered here. The other two sanitary protection zones, in which various restrictions apply, include the entire watershed with a number of industrial sites, for example local farmers pay extra for the restrictions. The curiosities are the unfinished bridges of the so-called protectorate highway above the surface and the two-story bridge, the current D1, which runs along the reservoir.
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