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Spillways
A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure that water does not damage parts of the structure not designed to convey water. Spillways can include floodgates and fuse plugs to regulate water flow and reservoir level. Such features enable a spillway to regulate downstream flow—by releasing water in a controlled manner before the reservoir is full, operators can prevent an unacceptably large release later. Other uses of the term "spillway" include bypasses of dams and outlets of channels used during high water, and outlet channels carved through natural dams such as moraines. Water normally flows over a spillway only during flood periods, when the reservoir has reached its capacity and water continues entering faster than it can be released. In contrast, an intake tower is a structur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stepped Spillway
A stepped spillway is a spillway with steps on the spillway chute to assist in the dissipation of the kinetic energy of the descending water. This reduces the need for an additional energy dissipator, such as a body of water, at the end of the spillway downstream. Historical developments Stepped spillways, consisting of Weir, weirs and channels, have been used for over 3,500 years since the first structures were built in Greece and Crete. During Classical Antiquity, Antiquity, the stepped-chute design was used for dam spillways, storm waterways, and in town water supply channels. Most of these early structures were built around the Mediterranean Sea, and the expertise on stepped spillway design was spread successively by the Romans, Muslims, and Spaniards. Although the early stepped spillways were built in cut-stone masonry, unlined rock, and timber, a wider range of construction materials was introduced during the mid-19th century, including the first concrete stepped spillway o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intake Tower
An intake tower or outlet tower is a vertical tubular structure with one or more openings used for capturing water from reservoirs and conveying it further to a hydroelectric or water-treatment plant. Unlike spillways, intake towers are intended for the reservoir's regular operation, conveying clean, debris-free water for further use. Construction An intake tower is typically made from reinforced concrete, with foundations laid in the river or lake bed. It has at least one water-collecting opening at the top, and may have additional openings along its height, depending on the purpose: towers for hydroelectric plants typically have only one inlet, while those in water-processing plants have multiple draw-off inlets. Near the bottom of the tower, depending on the dam construction and plant location, a horizontal or slanted outlet conduit takes the water from the tower into the plant. The most convenient location for an intake tower is in the proximity of the processing plant. In a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Jump
A hydraulic jump is a phenomenon in the science of hydraulics which is frequently observed in open channel flow such as rivers and spillways. When liquid at high velocity discharges into a zone of lower velocity, a rather abrupt rise occurs in the liquid surface. The rapidly flowing liquid is abruptly slowed and increases in height, converting some of the flow's initial kinetic energy into an increase in potential energy, with some energy irreversibly lost through turbulence to heat. In an open channel flow, this manifests as the fast flow rapidly slowing and piling up on top of itself similar to how a shockwave forms. It was first observed and documented by Leonardo da Vinci in the 1500s. The mathematics were first described by Giorgio Bidone of Turin University when he published a paper in 1820 called ''Experiences sur le remou et sur la propagation des ondes''. The phenomenon is dependent upon the initial fluid speed. If the initial speed of the fluid is below the critical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Government Printing Office
The United States Government Publishing Office (USGPO or GPO), formerly the United States Government Printing Office, is an agency of the Legislature, legislative branch of the Federal government of the United States, United States federal government. The office produces and distributes information products and services for all three branches of the Federal Government, including U.S. passports for the Department of State as well as the official publications of the Supreme Court of the United States, Supreme Court, the United States Congress, Congress, the Executive Office of the President of the United States, Executive Office of the President, United States federal executive departments, executive departments, and Independent agencies of the United States government, independent agencies. An act of Congress changed the office's name to its current form in 2014. History Establishment of the Government Printing Office The Government Printing Office was created by Joint resol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morning Glory
Morning glory (also written as morning-glory) is the common name for over 1,000 species of flowering plants in the family Convolvulaceae, whose taxonomy and systematics remain in flux. These species are distributed across numerous genus, genera, including: * ''Argyreia'' * ''Astripomoea'' * ''Calystegia'' * ''Convolvulus'' * ''Ipomoea'' (the largest genus) * ''Lepistemon'' * ''Merremia'' * ''Operculina'' * ''Rivea'' * ''Stictocardia'' ''Ipomoea tricolor'', commonly known simply as "morning glory", is the archetypical species for the group and is renowned for its many beautiful varieties, such as 'Heavenly Blue', 'Flying Saucers', and 'Pearly Gates'. As the name suggests, most morning glory flowers open early in the day and begin to fade by late morning, as the Corolla (botany), corolla starts to curl inward. They thrive in full sun and prefer mesic habitat, mesic soils. While many species are known for their diurnal blooming pattern, some, such as ''Ipomoea muricata'', ''Ipo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hungry Horse Dam
Hungry Horse Dam is an arch dam in the Western United States, on the South Fork Flathead River in the Rocky Mountains of northwest Montana. It is located in Flathead National Forest in Flathead County, about south of the west entrance to Glacier National Park, southeast of Columbia Falls, and northeast of Kalispell. The Hungry Horse project, dam, and powerplant are operated by the U.S. Bureau of Reclamation. The entrance road leading to the dam is located in Hungry Horse. The purposes of the Hungry Horse Project authorized by law are irrigation, flood control, navigation, streamflow regulation, hydroelectric generation, and other beneficial uses such as recreation. However, no irrigation facilities were built and the project has no irrigation obligations. Hydroelectric power generation and flood control are the primary purposes of the dam. The dam, reservoir, and surrounding area are used for recreation. Description At in height, the dam was the third largest and seco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geehi Dam
Geehi Dam is a major ungated rockfill embankment dam across the Geehi River in the Snowy Mountains of New South Wales, Australia. The reservoir impounded by the dam is known as Geehi Reservoir. History The structure was completed by Thiess Brothers in 1966, and is one of the sixteen major dams that comprise the Snowy Mountains Scheme, a vast hydroelectricity and irrigation complex constructed in south-east Australia between 1949 and 1974 that is now run by Snowy Hydro. Location and features The dam is located within what is now the Snowy Valleys local government area. It was constructed by Thiess Brothers based on engineering plans developed under contract by the Snowy Mountains Hydroelectric Authority. The dam wall, comprising of rockfill with an earth core, is high and long. At 100% capacity the dam wall holds back of water. The surface area of Geehi Reservoir is and the catchment area is . The uncontrolled bell-mouth spillway has a diameter of and is capable of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Return Period
A return period, also known as a recurrence interval or repeat interval, is an average time or an estimated average time between events such as earthquakes, floods, landslides, or river discharge flows to occur. The reciprocal value of return period is called the frequency of occurrence. It is a statistical measurement typically based on historic data over an extended period, and is used usually for risk analysis. Examples include deciding whether a project should be allowed to go forward in a zone of a certain risk or designing structures to withstand events with a certain return period. The following analysis assumes that the probability of the event occurring does not vary over time and is independent of past events. Estimating a return period Recurrence interval = :''n'' number of years on record; :''m'' is the rank of observed occurrences when arranged in descending order For floods, the event may be measured in terms of m3/s or height; for storm surges, in terms of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphon
A siphon (; also spelled syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the fall of the liquid as it flows down the tube under the pull of gravity, then discharging at a level lower than the surface of the reservoir from which it came. There are two leading theories about how siphons cause liquid to flow uphill, against gravity, without being pumped, and powered only by gravity. The traditional theory for centuries was that gravity pulling the liquid down on the exit side of the siphon resulted in reduced pressure at the top of the siphon. Then atmospheric pressure was able to push the liquid from the upper reservoir, up into the reduced pressure at the top of the siphon, like in a barometer or drinking straw, and then over. However, it has been demo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
100-year Flood
A 100-year flood, also called a 1% flood,Holmes, R.R., Jr., and Dinicola, K. (2010) ''100-Year flood–it's all about chance 'U.S. Geological Survey General Information Product 106/ref> is a flood event at a level that is reached or exceeded once per hundred years, long-run probability, on average. It has a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year. The estimated boundaries of inundation in a 100-year flood are marked on flood maps. Maps, elevations and flow rates For coastal flooding and lake flooding, a 100-year flood is generally expressed as a water level elevation or depth, and includes a combination of tide, storm surge, and wind wave, waves. For river systems, a 100-year flood can be expressed as a Discharge (hydrology), flow rate, from which the flood elevation is derived. The resulting area of inundation is referred to as the ''100-year floodplain''. Estimates of the 100-year flood flow rate and other streamflow statistics for any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
