Water level

Water level or gauge height or stage is the elevation of the free surface of a stream, lake or reservoir relative to a specified vertical datum.[1]

See also


  1. ^ ISO 772: 1996. Hydrometric determinations – Vocabulary and symbols.

Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, submarine, or other floating structure that holds water is called a ballast tank. Water should move in and out from the ballast tank to balance the ship. In a vessel that travels on the water, the ballast will remain below the water level, to counteract the effects of weight above the water level. The ballast may be redistributed in the vessel or disposed of altogether to change its effects on the movement of the vessel.


A bong (also water pipe, billy, bing, or moof) is a filtration device generally used for smoking cannabis, tobacco, or other herbal substances. In the bong shown in the photo, the gas flows from the lower port on the left to the upper port on the right.

In construction and function a bong is similar to a hookah, except smaller and especially more portable. A bong may be constructed from any air- and water-tight vessel by adding a bowl and stem apparatus (or slide) which guides air downward to below water level whence it bubbles upward ("bubbler") during use. To get fresh air into the bong and harvest the last remaining smoke, a hole known as the "carburetor", "carb", "choke", "bink", "rush", "shotty", "kick hole", or simply "hole", somewhere on the lower part of the bong above water level, is first kept covered during the smoking process, then opened to allow the smoke to be drawn into the respiratory system. On bongs without such a hole, the bowl and/or the stem are removed to allow air from the hole that holds the stem.

Bongs have been in use by the Hmong, in Laos and Thailand, and all over Africa for centuries. One of the earliest recorded uses of the word in the West is in the McFarland Thai-English Dictionary, published in 1944, which describes one of the meanings of bong in the Thai language as, "a bamboo waterpipe for smoking kancha, tree, hashish, or the hemp-plant." A January 1971 issue of the Marijuana Review also used the term.

Damdama Lake

Damdamaa reservoir in Sohna, district in the Indian state of Haryana. It is one of the biggest lakes in Haryana and with an area of 3,000 acres (12.14 km2). Damdama Lake was formed when a stone and earthen dam constructed by the British was commissioned for rain water harvesting in 1947. The lake, held by an embankment, is fed mainly by monsoon rain pouring into a trough at the base of the Aravali hills. The Lake greets visitors with a water level down to 20 ft (6.1 m). During monsoon the water level reaches up to 50 ft (15 m) - 70 ft (21 m).

Deadweight tonnage

Deadweight tonnage (also known as deadweight; abbreviated to DWT, D.W.T., d.w.t., or dwt) or tons deadweight (TDW) is a measure of how much weight a ship can carry, not its weight, empty or in any degree of load. DWT is the sum of the weights of cargo, fuel, fresh water, ballast water, provisions, passengers, and crew.DWT is often used to specify a ship's maximum permissible deadweight (i.e. when she is fully loaded so that her Plimsoll line is at water level), although it may also denote the actual DWT of a ship not loaded to capacity.


Gjevillvatnet (or Gjevilvatnet) is a lake in the municipality of Oppdal in Trøndelag county, Norway. It is located in the Trollheimen mountain range, about 5 kilometres (3.1 mi) south of the mountain Blåhøa and about 5 kilometres (3.1 mi) northwest of the village of Vognillan.The lake was regulated for hydroelectric power-production in the 1970s. Water is tapped from the bottom in the western part of the lake, for use in the Driva power station. In the spring, the water level can be 15 metres (49 ft) below the natural water level. The river Festa runs out of the lake Gjevillvatnet, and it was once a very good trout river from where the lake is now, all the way down to the intake dam at the old powerstation (Vardammen). This river now mostly runs dry every year due to the dam on Gjevillvatnet, and the trout are almost non-existent in the watercourse.

The Gjevilvass valley is still regarded as one of Norway's most scenic valleys, and a cruise boat runs on the lake during summer. Along the middle of the lake, lies the Gjevillvasshytta, a lodge owned by Trondheim Turistforening. Here guests can eat, sleep, and use the lodge as a starting point for walking trips in the Trollheimen mountains.

Hydraulic telegraph

A hydraulic telegraph (Greek: υδραυλικός τηλέγραφος) is either of two different hydraulic-telegraph telecommunication systems. The earliest one was developed in 4th-century BC Greece, while the other was developed in 19th-century AD Britain. The Greek system was deployed in combination with semaphoric fires, while the latter British system was operated purely by hydraulic fluid pressure.

Although both systems employed water in their sending and receiver devices, their transmission media were completely different. The ancient Greek system transmitted its semaphoric information to the receiver visually, which limited its use to line-of-sight distances in good visibility weather conditions only. The 19th-century British system used water-filled pipes to effect changes to the water level in the receiver unit (similar to a transparent water-filled flexible tube used as a level indicator), thus limiting its range to the hydraulic pressure that could be generated at the transmitter's device.While the Greek device was extremely limited in the codes (and hence the information) it could convey, the British device was never deployed in operation other than for very short-distance demonstrations. The British device could, however, be used in any visibility within its range of operation so long as its conduits, if unheated, did not freeze in sub-zero temperatures —which contributed to its impracticality.


Kosapet (Tamil: குயபெட்டை) is a suburb of Chennai. The name is a corruption of Kuyavar Pettai ("Potter's Locality"), and originated due to the concentration of potters and artisans in this area. The area is Ward 98 (Zone 7) of Chennai Corporation.

Kosapet is situated near Purasawalkam. Kuyavar Pettai is the original name. The locality is popular for many events and festival celebrations which is unique in every street. Kandasami temple which is one of the oldest temples in this area is famous for its festivals such as bramha utsav, kandasasti and other celebrations. There is a tank which belongs to the temple; it helps to keep the ground water level intact.

Lake Lanier

Lake Lanier (officially Lake Sidney Lanier) is a reservoir in the northern portion of the U.S. state of Georgia. It was created by the completion of Buford Dam on the Chattahoochee River in 1956, and is also fed by the waters of the Chestatee River. The lake encompasses 38,000 acres (150 km2) or 59 square miles of water, and 692 miles (1,114 km) of shoreline at normal level, a "full summer pool" of 1,071 feet (326 m) above mean sea level. Named for American poet Sidney Lanier, it was built and is operated by the U.S. Army Corps of Engineers for flood control and water supplies. It is patrolled by the Georgia Department of Natural Resources (GDNR), as well as local law enforcement.

The states of Georgia, Alabama and Florida all have rights to the water of the reservoir, as it feeds rivers going through those areas. The Corps of Engineers has responsibilities to regulate flow for flood control and water use. In addition, it has to ensure that water is available to fulfill such federal mandates as under the Endangered Species Act, to support downstream species. The rapid suburbanization of the Atlanta region, in particular, has greatly increased water consumption by private homeowners for lawns and gardens. During droughts of the 21st century, Lake Lanier reached record lows, and regional actions have been needed to reduce area water usage.

Lake Mead

Lake Mead is a man made lake that lies on the Colorado River, about 24 mi (39 km) from the Las Vegas Strip, southeast of the city of Las Vegas, Nevada, in the states of Nevada and Arizona. It is the largest reservoir in the United States in terms of water capacity. Formed by the Hoover Dam on September 30, 1935, the reservoir serves water to the states of Arizona, California, and Nevada, as well as some of Mexico, providing sustenance to nearly 20 million people and large areas of farmland.At maximum capacity, Lake Mead is 112 miles (180 km) long, 532 feet (162 m) at its greatest depth, has a surface elevation of 1,221.4 feet (372.3 m) above sea level and 247 square miles (640 km2) of surface area, and contains 26.12 million acre feet (32,220,000 ML) of water.

The lake has not yet reached full capacity, however, since 1983 due to a combination of drought and increased water demand. As of August 2017, Lake Mead was at approximately 40% of full capacity with 10 million acre feet (12,000,000 ML) of held water. It has been smaller than Lake Powell (the second largest US reservoir when both are full) since 2013.

Merrymeeting Lake

Merrymeeting Lake is a 1,233-acre (4.99 km2) water body located in Strafford County in eastern New Hampshire, United States, in the town of New Durham. Its outlet is the Merrymeeting River, flowing south and then northwest to Lake Winnipesaukee.

The shores of Merrymeeting Lake are moderately to heavily developed. The lake has a busy recreational character rather than a wilderness character. Only a few small segments of shoreline remain undeveloped. The undeveloped areas are the western side of Sawtooth Cove, because the land is extremely steep there and difficult to build on, and the far eastern shore of the lake which is not easily accessible by road.

In the 1980s, most buildings along the lake were simple summer camps. During the 1990s, most of these structures were replaced by higher end summer homes, some worth millions of dollars. The town of New Durham maintains two paved roads, North Shore Road and South Shore Road, which almost encircle the lake, allowing for year-round residence. However, the winter population is small. Most properties on the lake are second homes for affluent families.

There is a dam at the west end of the lake, which is used to control the lake's water level. Each year in the fall the water level in the lake is lowered via the dam. Water level is restored to its normal level in the spring by snow melt and rainfall. The Powder Mill Fish Hatchery is located at the base of the dam, and is fed by the overflow of the lake's water.Merrymeeting Lake has common loons which nest on the western shore. Ducks also live on the lake, although feeding them is discouraged by the Merrymeeting Lake Association. The New Hampshire Fish and Game Department stocks the lake for recreational fishing. The lake is classified as a cold- and warmwater fishery, with observed species including rainbow trout, landlocked salmon, lake trout, smallmouth bass, chain pickerel, and horned pout.


A body of water, such as a river, canal or lake, is navigable if it is deep, wide and slow enough for a vessel to pass or walk. Preferably there are few obstructions such as rocks or trees to avoid. Bridges must have sufficient clearance. High water speed may make a channel unnavigable. Waters may be unnavigable because of ice, particularly in winter. Navigability depends on context: A small river may be navigable by smaller craft, such as a motorboat or a kayak, but unnavigable by a cruise ship. Shallow rivers may be made navigable by the installation of locks that increase and regulate water depth, or by dredging.

New York Central Railroad

The New York Central Railroad (reporting mark NYC) was a railroad primarily operating in the Great Lakes region of the United States. The railroad primarily connected greater New York and Boston in the east with Chicago and St. Louis in the Midwest along with the intermediate cities of Albany, Buffalo, Cleveland, Cincinnati, and Detroit. New York Central was headquartered in New York City's New York Central Building, adjacent to its largest station, Grand Central Terminal.

The railroad was established in 1853, consolidating several existing railroad companies. In 1968 the NYC merged with its former rival, the Pennsylvania Railroad, to form Penn Central. Penn Central went bankrupt in 1970 and merged into Conrail in 1976. Conrail was broken up in 1998, and portions of its system were transferred to CSX and Norfolk Southern Railway, with CSX acquiring most of the old New York Central trackage.

Extensive trackage existed in the states of New York, Pennsylvania, Ohio, Michigan, Indiana, Illinois, Massachusetts and West Virginia plus additional trackage in the Canadian provinces of Ontario and Quebec. At the end of 1925, the NYC operated 11,584 miles (18,643 km) of road and 26,395 miles (42,479 km) of track; at the end of 1967 the mileages were 9,696 miles (15,604 km) and 18,454 miles (29,699 km).

Pasig River

The Pasig River (Filipino: Ilog Pasig and Spanish: Río Pásig) is a river in the Philippines that connects Laguna de Bay to Manila Bay. Stretching for 25 kilometres (15.5 mi), it bisects the Philippine capital of Manila and its surrounding urban area into northern and southern halves. Its major tributaries are the Marikina River and San Juan River. The total drainage basin of Pasig River, including the basin of Laguna de Bay, covers 4,678 square kilometres (1,806 sq mi).The Pasig River is technically a tidal estuary, as the flow direction depends upon the water level difference between Manila Bay and Laguna de Bay. During the dry season, the water level in Laguna de Bay is low with the river's flow direction dependent on the tides. During the wet season, when the water level of Laguna de Bay is high, the flow is reversed towards Manila Bay.

The Pasig River used to be an important transport route and source of water for Spanish Manila. Due to negligence and industrial development, the river has become very polluted and is considered biologically dead (i.e., unable to sustain life) by ecologists. The Pasig River Rehabilitation Commission (PRRC), which was established to oversee rehabilitation efforts for the river, is supported by private sector organisations such as the Clean and Green Foundation, Inc. that introduced the Piso para sa Pasig (Filipino: "A peso for Pasig") campaign in the 1990s.


A piezometer is either a device used to measure liquid pressure in a system by measuring the height to which a column of the liquid rises against gravity, or a device which measures the pressure (more precisely, the piezometric head) of groundwater at a specific point. A piezometer is designed to measure static pressures, and thus differs from a pitot tube by not being pointed into the fluid flow.

Observation wells give some information on the water level in a formation, but must be read manually. Electrical pressure transducers of several types can be read automatically, making data acquisition more convenient.

Reed bed

Reed beds are natural habitats found in floodplains, waterlogged depressions, and

estuaries. Reed beds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. As reed beds age, they build up a considerable litter layer that eventually rises above the water level and that ultimately provides opportunities for scrub or woodland invasion. Artificial reed beds are used to remove pollutants from grey water.


A sluice (from the Dutch "sluis") is a water channel controlled at its head by a gate. A mill race, leet, flume, penstock or lade is a sluice channelling water toward a water mill. The terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry.

A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway. Sluice gates commonly control water levels and flow rates in rivers and canals. They are also used in wastewater treatment plants and to recover minerals in mining operations, and in watermills.

Stream gauge

A stream gauge, streamgage or gauging station is a location used by hydrologists or environmental scientists to monitor and test terrestrial bodies of water. Hydrometric measurements of water level surface elevation ("stage") and/or volumetric discharge (flow) are generally taken and observations of biota and water quality may also be made. The location of gauging stations are often found on topographical maps. Some gauging stations are highly automated and may include telemetry capability transmitted to a central data logging facility.

Tidewater (region)

Tidewater is a reference to the Atlantic coastal plain region of the United States of America. It includes the low-lying plains of southeast Virginia, northeastern North Carolina, southern Maryland and the Chesapeake Bay. The area got its name from the effects of the changing tides on local rivers, sounds, and the ocean; there is also a cultural heritage that sets the Tidewater regions apart from other parts of the United States. Tidewater region was founded on principles of English gentry in a developing nation where patriotism, freedom and waterborne livelihoods existed. Dialects are distinctive and eroding along with islands and shoreline.

Tidewater region is generally flat and low flooded river plains composed of tidal marsh and large expanses of swamp. Much of the area is covered with pocosin and the higher areas are used for agricultural farmlands. Geographically, in North Carolina and Virginia the Tidewater area is the land between the Suffolk Scarp and the Atlantic Ocean. In Maryland the Tidewater area is the flooded river areas below the Fall Line. The Hampton Roads area of Virginia is considered to be a Tidewater region. Southern Maryland and the Eastern Shore, parts of Delaware round out the northern part of the region on the Chesapeake and Delaware Bays.

The term tidewater may be correctly applied to all portions of any area, including Virginia, where the water level is affected by the tides (more specifically, where the water level rises when the tide comes in). In the case of Virginia, the Tidewater region includes the land east of the Fall Line, the natural border with the Piedmont Region. It includes Hampton Roads, the rest of the Virginia Peninsula, the Middle Peninsula, the Northern Neck, and the Eastern Shore.

Planters in the early American colonies extended their tobacco productions above the Fall Line, where waterfalls or rapids mark the end of the Tidewater and the beginning of the foothill region known as the Piedmont.Tidewater is host to flora commonly associated with the South Atlantic pine forests and lower Southeast Coastal Plain maritime flora, the latter found primarily in southeastern Virginia.

Water table

The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water.The water table is the surface where the water pressure head is equal to the atmospheric pressure (where gauge pressure = 0). It may be visualized as the "surface" of the subsurface materials that are saturated with groundwater in a given vicinity.The groundwater may be from precipitation or from groundwater flowing into the aquifer. In areas with sufficient precipitation, water infiltrates through pore spaces in the soil, passing through the unsaturated zone. At increasing depths, water fills in more of the pore spaces in the soils, until a zone of saturation is reached. Below the water table, in the phreatic zone (zone of saturation), layers of permeable rock that yield groundwater are called aquifers. In less permeable soils, such as tight bedrock formations and historic lakebed deposits, the water table may be more difficult to define.

The water table should not be confused with the water level in a deeper well. If a deeper aquifer has a lower permeable unit that confines the upward flow, then the water level in this aquifer may rise to a level that is greater or less than the elevation of the actual water table. The elevation of the water in this deeper well is dependent upon the pressure in the deeper aquifer and is referred to as the potentiometric surface, not the water table.

Wave setup

In fluid dynamics, wave setup is the increase in mean water level due to the presence of breaking waves. Similarly, wave setdown is a wave-induced decrease of the mean water level before the waves break (during the shoaling process). For short, the whole phenomenon is often denoted as wave setup, including both increase and decrease of mean elevation. This setup is primarily present in and near the coastal surf zone. Besides a spatial variation in the (mean) wave setup, also a variation in time may be present – known as surf beat – causing infragravity wave radiation.

Wave setup can be mathematically modeled by considering the variation in radiation stress (Longuet-Higgins & Stewart 1962). Radiation stress is the tensor of excess horizontal-momentum fluxes due to the presence of the waves.

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