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Head (hydrology)
In hydrology, the head is the point on a watercourse up to which it has been artificially broadened and/or raised by an impoundment. Above the head of the reservoir natural conditions prevail; below it the water level above the riverbed has been raised by the impoundment and its flow rate reduced, unless and until banks, barrages, weir sluices or dams are overcome (overtopped), whereby a less frictional than natural course will exist (mid-level and surface rather than bed and bank currents) resulting in flash flooding below. In principle, a distinction must be drawn between the head of a reservoir impounded by a dam, and the head of a works resulting from a barrage or canal locks. Head of a reservoir A head's location varies with the height of the water level against the dam. Since there is only an extremely low flow within the reservoir so no water level gradient, the head can be clearly seen: where the farthest watercourse discharges into the reservoir. Upstream of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fürstenteich 042
The Fürstenteich is a reservoir near Silberhütte in the German state of Saxony-Anhalt. It has an earth-filled dam with an impervious core. It impounds the Teufelsgrundbach stream. Construction The dam was based on sedimented shale and has an internal impervious core of organic clays (grass sods). During renovation work about 70 cm of the surface layer on the old downstream face was removed and replaced by layers of shale material. That was covered with a 10 cm thick layer of topsoil sown with grass seed. On the upstream side, 60 cm was removed and on a 30 cm thick layer of stone chippings a similarly thick protective layer of ballast. The dam was also raised in height by about 1 metre. After removing 90 cm of the old dam crest, a metre-wide toe wall was integrated from the subgrade (''Planum''). This extends as far as the cohesive earth material of the old dam core. The old wooden outlet channel (''Striegelgerinne'') is still there, but no longe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moselle
The Moselle ( , ; german: Mosel ; lb, Musel ) is a river that rises in the Vosges mountains and flows through north-eastern France and Luxembourg to western Germany. It is a left bank tributary of the Rhine, which it joins at Koblenz. A small part of Belgium is in its basin as it includes the Sauer and the Our. Its lower course "twists and turns its way between Trier and Koblenz along one of Germany's most beautiful river valleys."''Moselle: Holidays in one of Germany's most beautiful river valleys'' at www.romantic-germany.info. Retrieved 23 Jan 2016. In this section the land to the north is the Eifel which stretches into |
Staff (head) Gauge
A staff gauge or head gauge is calibrated scale which is used to provide a visual indication of liquid level. When installed perpendicular to an inclined or sloped surface, a staff gauge is usually calibrated so that the indicated level is the true vertical level. Staff gauges are commonly installed at stream gauging stations to indicate the water stage or water level. They are also used to indicate the level (and hence flow rate) in open channel primary devices (flumes or weirs); see discharge (hydrology). See also * Head (hydrology) * Level staff {{short description, Graduated rod used to measure differences between heights A level staff, also called levelling rod, is a graduated wooden or aluminium rod, used with a levelling instrument to determine the difference in height between points ... {{water-stub Water supply Hydrology instrumentation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Head
Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22. It is usually measured as a liquid surface elevation, expressed in units of length, at the entrance (or bottom) of a piezometer. In an aquifer, it can be calculated from the depth to water in a piezometric well (a specialized water well), and given information of the piezometer's elevation and screen depth. Hydraulic head can similarly be measured in a column of water using a standpipe piezometer by measuring the height of the water surface in the tube relative to a common datum. The hydraulic head can be used to determine a ''hydraulic gradient'' between two or more points. "Head" in fluid dynamics In fluid dynamics, ''head'' is a concept that relates the energy in an incompressible fluid to the height of an equivalent static column of that fluid. From Bernoulli's principle, the total energy at a given point in a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flood Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can be used for any given locale to find the predicted times and amplitude (or "tidal range"). The predictions are influenced by many factors including the alignment of the Sun and Moon, the phase and amplitude of the tide (pattern of tides in the deep ocean), the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry (see '' Timing''). They are however only predictions, the actual time and height of the tide is affected by wind and atmospheric pressure. Many shorelines experience semi-diurnal tides—two nearly equal high and low tides each day. Other locations have a diurnal tide—one high and low tide each day. A "mixed tide"—two uneven magnitude tides a day—is a third regular category. Tides va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebb Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can be used for any given locale to find the predicted times and amplitude (or " tidal range"). The predictions are influenced by many factors including the alignment of the Sun and Moon, the phase and amplitude of the tide (pattern of tides in the deep ocean), the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry (see '' Timing''). They are however only predictions, the actual time and height of the tide is affected by wind and atmospheric pressure. Many shorelines experience semi-diurnal tides—two nearly equal high and low tides each day. Other locations have a diurnal tide—one high and low tide each day. A "mixed tide"—two uneven magnitude tides a day—is a third regular category. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jubilee River
The Jubilee River is a hydraulic channel in southern England. It is long and is on average wide. It was constructed in the late 1990s and early 2000s to take overflow from the River Thames and so alleviate flooding to areas in and around the towns of Maidenhead, Windsor, and Eton in the counties of Berkshire and Buckinghamshire. It achieves this by taking water from the left (at this point eastern) bank of the Thames upstream of Boulter's Lock near Maidenhead and returning it via the north bank downstream of Eton. Although successful in its stated aims, residents of villages downstream, such as Wraysbury, claim it has increased flooding in those locations. Construction Parts of the towns of Windsor, Eton and Maidenhead are prone to flooding, because they are built on the flood plain of the River Thames. The concept of a parallel channel which could take water from the Thames above Maidenhead and return it below Windsor was conceived in the 1980s, and became known as the Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flood Meadow
A flood-meadow (or floodmeadow) is an area of grassland or pasture beside a river, subject to seasonal flooding.Huhta, Ari‐Pekka, Rautio, Pasi (2014). Flood meadows in Finland - their development during the past century. ''Nordic Journal of Botany'' 32 (6): 858–70 Flood-meadows are distinct from water-meadows in that the latter are artificially created and maintained, with flooding controlledEmma Rothero, Sophie Lake, David Gowing, eds. Floodplain Meadows – Beauty and Utility: A Technical Handbook' (Floodplain Meadows Partnership; 2016) on a seasonal and even daily basis. Examples Austria: * Hohenau an der March Bosnia and Herzegovina: * List of karst polje in Bosnia and Herzegovina Estonia: * Emajõe flood-meadow * Kasari, Matsalu National Park Finland: * Mattholmsfladan, Pargas * Levänluhta, Isokyrö Ireland: * Shannon Callows United Kingdom: * Angel & Greyhound Meadow, Oxford * Christchurch Meadows, Reading * Christ Church Meadow, Oxford * Mill Meadows, He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Headworks
Headworks is a civil engineering term for any structure at the head or diversion point of a waterway. It is smaller than a barrage and is used to divert water from a river into a canal or from a large canal into a smaller canal. at Web archive An example is the Horseshoe falls at the start of the Llangollen canal The Llangollen Canal ( cy, Camlas Llangollen) is a navigable canal crossing the border between England and Wales. The waterway links Llangollen in Denbighshire, north Wales, with Hurleston in south Cheshire, via the town of Ellesmere, Shropshir .... Historically the phrase "headworks" derives from the traditional approach of diverting water at the start of an irrigation network and the location of these processes at the "head of the works". See also * List of barrages and headworks in Pakistan References Civil engineering Irrigation {{Civil-engineering-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrology
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management. Hydrology subdivides into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management, and water quality, where water plays the central role. Oceanography and meteorology are not included because water is only one of many important aspects within those field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pre-dam
A forebay is an artificial pool of water in front of a larger body of water. The larger body of water may be natural or man-made. at www.wisegeek.com. Retrieved on 13 Jun 2013 Forebays have a number of functions. They are used in to act as a buffer during or s, impounding water and releasing in a controlled way into the larger waterbody. They may be used upstream of |
Canal Locks
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 fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is the chamber itself (usually then called a 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. Later canals used more and larger locks to allow a more direct route to be taken. Pound lock A ''pound lock'' is most commonly used on canals and rivers today. A pound lock has a chamber with gates at both ends that control the level of water in the pound. In contrast, an earlier design with a single gate was known as a flash lock. Pound locks were first used in China during the Song Dynasty (960–1279 AD), having been pioneered by the Song politician and naval eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
