The Orlík Waterworks, built on the 144.65 river kilometre of the Vltava during the years 1956 to 1966, is not only the largest dam in the entire Vltava cascade but also, when it comes to the volume of water, the largest lake in the Czech Republic. When full it has a length of 68 km on the Vltava and reaches beyond Týn nad Vltavou, all the way to Hněvkovice. On the Otava River, which is also affected by the backwater of the Vltava, the lake reaches a distance of 22 km all the way to the town of Písek. The water surface area of the Orlík reservoir is 2,640 ha (in comparison, Lipno I has an area of 4,870 ha), the volume of the contained water is 703.8 million m³ (Lipno I has “only” 309.5 million m³), and the circumference of the shore is approximately 300 km.
The parameters of the dam, among other things, attest to the size of the Orlík Waterworks: The concrete gravitational dam is straight, at the crown it is 450 metres long, and at the highest point above the base it is 90.5 metres high (the highest dam in the Czech Republic). It is equipped with three overflows each 15 metres wide, with a capacity of 2,184 m³ per second, and two bottom spillways with a capacity of 2 x 185.5 m³ per second.
The great water gradient (a min. 45 and max. 71.5 metres) is utilised by the hydroelectric power station on the left bank. It is equipped with four Kaplan turbines, each with a water flow rate of 150 m³ per second. The output of the power station is 364 MW.
The dam is equipped with two boat lifts on the right bank for boat transport: Only the construction of the large hoisting equipment, for vessels having displacements up to 300 tonnes, has been completed for the time being, the technological part is missing. A small boat lift is operational and can transport sports vessels and has a capacity of up to 3.5 tonnes.
The primary purposes of the Orlík Waterworks are the accumulation of water for improving the water flow of the lower section of the Vltava (and also the Labe (Elbe)), protection of the area below the dam, including Prague, from floods, and also the generation of electricity. Of course, this also includes the utilisation of the lake for sports, recreation and fishing activities and also for boating.
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