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Štěchovice Reservoir
Štěchovice Reservoir () is a reservoir on the Vltava River in the Central Bohemian Region of the Czech Republic. It was built from 1937 to 1945 as the second stage of the Vltava Cascade. The reservoir is named after the market town of Štěchovice. The construction started before World War II and because of the need for electricity resources were allocated for the project in spite of general shortage. The power station was put in action in 1943. The reservoir had flooded St John's Rapids (''Svatojánské proudy''). The main role of the reservoir is to balance the water runoff from peak-load power station at Slapy Reservoir and to propel two Kaplan turbines with total installed power 2 x 11.25 MW (Štěchovice I). A lock (20.1 m difference between water levels, length 118 m) handles ships with displacement up to 1,000 tons. The reservoir is also used by the pumped-storage hydroelectric plant Štěchovice II whose upper reservoir was created on the top of hill Homole. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reservoir
A reservoir (; ) is an enlarged lake behind a dam, usually built to water storage, store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an Bay, embayment within it, excavating, or building any number of retaining walls or levees to enclose any area to store water. Types Dammed valleys Dammed reservoirs are artificial lakes created and controlled by a dam constructed across a valley and rely on the natural topography to provide most of the basin of the reservoir. These reservoirs can either be ''on-stream reservoirs'', which are located on the original streambed of the downstream river and are filled by stream, creeks, rivers or rainwater that surface runoff, runs off the surrounding forested catchments, or ''off-stream reservoirs'', which receive water diversion, diverted water from a nearby stream or aqueduct (water supply), aq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Displacement (fluid)
In fluid mechanics, displacement occurs when an object is largely immersed in a fluid, pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, and from this, the volume of the immersed object can be deduced: the volume of the immersed object will be exactly equal to the volume of the displaced fluid. An object immersed in a liquid displaces an amount of fluid equal to the object's volume. Thus, buoyancy is expressed through Archimedes' principle, which states that the weight of the object is reduced by its volume multiplied by the density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ... of the fluid. If the weight of the object is less than this displaced quantity, the object floats; if more, it sinks. The amount of fluid displace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prague-West District
Prague-West District () is a district in the Central Bohemian Region of the Czech Republic. Its capital is Prague. The most populated town of the district is Jesenice. Administrative division Prague-West District is formed by only one administrative district of municipality with extended competence: Černošice. List of municipalities Towns are marked in bold and market towns in ''italics'': Bojanovice – Bratřínov – Březová-Oleško – Buš – Černolice – Černošice – Červený Újezd – Choteč – Chrášťany – Chýně – Chýnice – Číčovice – Čisovice – Davle – Dobříč – Dobřichovice – Dobrovíz – Dolní Břežany – Drahelčice – Holubice – Horoměřice – Hostivice – Hradištko – Hvozdnice – Jeneč – Jesenice – Jílové u Prahy – Jíloviště – Jinočany – Kamenný Přívoz – Karlík – Klínec – Kněževes – Kosoř – Kytín – Lety – Libčice nad Vltavou – L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroelectric Power Stations In The Czech Republic
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other renewable sources combined and also more than nuclear power. Hydropower can provide large amounts of low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel-powered energy plants. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reservoirs In The Czech Republic
A reservoir (; ) is an enlarged lake behind a dam, usually built to store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, excavating, or building any number of retaining walls or levees to enclose any area to store water. Types Dammed valleys Dammed reservoirs are artificial lakes created and controlled by a dam constructed across a valley and rely on the natural topography to provide most of the basin of the reservoir. These reservoirs can either be ''on-stream reservoirs'', which are located on the original streambed of the downstream river and are filled by creeks, rivers or rainwater that runs off the surrounding forested catchments, or ''off-stream reservoirs'', which receive diverted water from a nearby stream or aqueduct or pipeline water from other on-stream reservoirs. Dams are typically loc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hectare
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, square metres (), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about and one hectare contains about . In 1795, when the metric system was introduced, the ''are'' was defined as 100 square metres, or one square decametre, and the hectare (" hecto-" + "are") was thus 100 ''ares'' or km2 ( square metres). When the metric system was further rationalised in 1960, resulting in the International System of Units (), the ''are'' was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI and whose use is "expected to continue indefinitely". Though the dekare/decare daa () and are (100 m2) are not officially "accepted for use", they are still used in some contexts. Description The hectare (), although not a unit of SI, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2002 European Floods
In August 2002, a week of intense rainfall produced flooding across a large portion of Europe. It reached the Czech Republic, Italy, Spain, Austria, Germany, Slovakia, Hungary, Romania, Bulgaria, Croatia, Ukraine and Russia. The event killed 232 people and left (US$27.115 billion) in damage. The flood was of a magnitude expected to occur roughly once a century. Flood heights unknown since St. Mary Magdalene's flood were recorded. Development Flooding resulted from the passage of two Genoa low pressure systems (named Hanne and Ilse by the Free University of Berlin) which brought warm moist air from the Mediterranean northwards. The effects of El Niño may have contributed. The floods gradually moved eastwards along the Danube, although the damage in the large cities on its shores was not as severe as in the areas affected by the floods later. When the rainfall moved northeast to the Bohemian Forest and the source areas of the Elbe and Vltava rivers, the results w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis Turbine
The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency. The process of arriving at the modern Francis runner design took from 1848 to approximately 1920. It became known as the Francis turbine around 1920, being named after British-American engineer James B. Francis who in 1848 created a new turbine design. Francis turbines are primarily used for producing electricity. The power output of the electric generators generally ranges from just a few kilowatts up to 1000 MW, though mini-hydro installations may be lower. The best performance is seen when the head height is between . Penstock diameters are between . The speeds of different turbine units range from 70 to 1000 rpm. A wicket gate around the outside of the turbine's rotating runner controls the rate of water flow through the turbine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pumped-storage Hydroelectricity
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing (electrical power), load balancing. A PSH system stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through water turbine, turbines to produce electric power. Pumped-storage hydroelectricity allows energy from Intermittent energy source, intermittent sources (such as solar power, solar, Wind power, wind, and other renewables) or excess electricity from continuous base-load sources (such as coal or nuclear) to be saved for periods of higher demand. The reservoirs used with pumped storage can be quite small, when contrasted with the lakes of conventional hydroelectric plants of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock (water Transport)
A lock is a device used for raising and lowering boats, ships and other watercraft between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a chamber in a permanently fixed position in which the water level can be varied. (In a caisson lock, a boat lift, or on a canal inclined plane, it is the chamber itself (usually then called a caisson (engineering), caisson) that rises and falls.) Locks are used to make a river more easily navigable, or to allow a canal to cross land that is not level. Over time, more and larger locks have been used in canals to allow a more direct route to be taken. History Ancient Egypt In Ancient Egypt, the river-locks was probably part of the Canal of the Pharaohs: Ptolemy II is credited by some for being the first to solve the problem of keeping the Nile free of salt water when his engineers invented the lock around 274/273 BC. Ancient China During 960–1279 CE, the natural extension o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vltava
The Vltava ( , ; ) is the longest river in the Czech Republic, a left tributary of the Elbe River. It runs southeast along the Bohemian Forest and then north across Bohemia, through Český Krumlov, České Budějovice, and Prague. It is commonly referred to as the "Czech national river". Etymology Both the Czech name ' and the German name ' are believed to originate from the old Germanic words ' 'wild water' (compare Latin '). In the ' (872 AD) it is called '; from 1113 AD it is attested as '. In the ' (1125 AD) it is attested for the first time in its Bohemian form, '. Course The Vltava originates by a confluence of two rivers, the Teplá Vltava, which is longer, and the Studená Vltava, originating in Bavaria. From a water management point of view, the Vltava and Teplá Vltava are one river with single numbering of river kilometres. The Teplá Vltava originates in the territory of Kvilda in the Bohemian Forest at an elevation of , on the slope of the Čern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megawatt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work (physics), energy transfer. The watt is named in honor of James Watt (1736–1819), an 18th-century Scottish people, Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own Watt steam engine, steam engine in 1776, which became fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one meter per second against a constant opposing force of one Newton (unit), newton, the rate at which Work (physics), work is done is one watt. \mathrm. In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
