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单词 dam
释义

dam


dam

a barrier built to hold back water and raise its level; block up; obstruct: The beaver’s dam caused the field to flood.
Not to be confused with:damn – an uttered curse; to doom to hell; condemn; censure: Damn the act, not the person.; commend without enthusiasm: damn with faint praise; a bit: not worth a damn

dam 1

D0014500 (dăm)n.1. a. A barrier constructed across a waterway to control the flow or raise the level of water.b. A body of water controlled by such a barrier.2. A barrier against the passage of liquid or loose material, as a rubber sheet used in dentistry to isolate one or more teeth from the rest of the mouth.tr.v. dammed, dam·ming, dams 1. To hold back or confine by means of a dam.2. To close up; obstruct: He tried to dam his grief.
[Middle English.]
dam′mer n.

dam 2

D0014500 (dăm)n.1. A female parent of an animal, especially a domesticated mammal such as a horse.2. Archaic A mother.
[Middle English dam, dame, lady, mother; see dame.]

dam 3

abbr. decameter

dam

(dæm) n1. (Civil Engineering) a barrier of concrete, earth, etc, built across a river to create a body of water for a hydroelectric power station, domestic water supply, etc2. (Civil Engineering) a reservoir of water created by such a barrier3. something that resembles or functions as a damvb, dams, damming or dammed (often foll by: up) to obstruct or restrict by or as if by a dam[C12: probably from Middle Low German; compare Old Icelandic damma to block up]

dam

(dæm) n (Breeds) the female parent of an animal, esp of domestic livestock[C13: variant of dame]

dam

(dæm) interj, adv, adj (often used in combination) a variant spelling of damn1, damn2, damn3, damn4: damfool; dammit.

dam

symbol for (Units) decametre(s)

Dam

(Danish dam) n (Biography) (Carl Peter) Henrik (ˈhɛnrəɡ). 1895–1976, Danish biochemist who discovered vitamin K (1934): Nobel prize for physiology or medicine 1943

dam1

(dæm)

n., v. dammed, dam•ming. n. 1. a barrier to obstruct the flow of water, esp. one of earth, masonry, etc., built across a stream or river. 2. a body of water confined by a dam. 3. any barrier resembling a dam. v.t. 4. to furnish with a dam; obstruct or confine with a dam. 5. to stop up; block up. [1275–1325; Middle English < Middle Dutch, Middle Low German dam; akin to Old English for-demman to stop up, block]

dam2

(dæm)

n. a female parent (used esp. of four-footed domestic animals). [1250–1300; Middle English; variant of dame]

dam

dekameter.

dam


Past participle: dammed
Gerund: damming
Imperative
dam
dam
Present
I dam
you dam
he/she/it dams
we dam
you dam
they dam
Preterite
I dammed
you dammed
he/she/it dammed
we dammed
you dammed
they dammed
Present Continuous
I am damming
you are damming
he/she/it is damming
we are damming
you are damming
they are damming
Present Perfect
I have dammed
you have dammed
he/she/it has dammed
we have dammed
you have dammed
they have dammed
Past Continuous
I was damming
you were damming
he/she/it was damming
we were damming
you were damming
they were damming
Past Perfect
I had dammed
you had dammed
he/she/it had dammed
we had dammed
you had dammed
they had dammed
Future
I will dam
you will dam
he/she/it will dam
we will dam
you will dam
they will dam
Future Perfect
I will have dammed
you will have dammed
he/she/it will have dammed
we will have dammed
you will have dammed
they will have dammed
Future Continuous
I will be damming
you will be damming
he/she/it will be damming
we will be damming
you will be damming
they will be damming
Present Perfect Continuous
I have been damming
you have been damming
he/she/it has been damming
we have been damming
you have been damming
they have been damming
Future Perfect Continuous
I will have been damming
you will have been damming
he/she/it will have been damming
we will have been damming
you will have been damming
they will have been damming
Past Perfect Continuous
I had been damming
you had been damming
he/she/it had been damming
we had been damming
you had been damming
they had been damming
Conditional
I would dam
you would dam
he/she/it would dam
we would dam
you would dam
they would dam
Past Conditional
I would have dammed
you would have dammed
he/she/it would have dammed
we would have dammed
you would have dammed
they would have dammed
Thesaurus
Noun1.dam - a barrier constructed to contain the flow of water or to keep out the seadike, dykebarrier - a structure or object that impedes free movementmilldam - dam to make a millpond to provide power for a water millweir - a low dam built across a stream to raise its level or divert its flow
2.dam - a metric unit of length equal to ten metersdecameter, decametre, dekameter, dekametre, dkmmetric linear unit - a linear unit of distance in metric termsm, meter, metre - the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards)hectometer, hectometre, hm - a metric unit of length equal to 100 meters
3.dam - female parent of an animal especially domestic livestockfemale - an animal that produces gametes (ova) that can be fertilized by male gametes (spermatozoa)
Verb1.dam - obstruct with, or as if with, a dam; "dam the gorges of the Yangtse River"dam upobturate, occlude, close up, impede, obstruct, jam, block - block passage through; "obstruct the path"

dam

noun1. barrier, wall, barrage, obstruction, embankment, hindrance They went ahead with plans to build a dam across the river.verb1. block up, block, hold in, restrict, check, confine, choke, hold back, barricade, obstruct The reservoir was formed by damming the River Blith.

dam

verbTo stop or prevent passage of:bar, block, impede, obstruct.Idiom: be in the way of.
Translations
堤坝拦在堤坝里的水水坝筑坝拦水

dam

(dӕm) noun1. a bank or wall of earth, concrete etc to keep back water. A new dam was being built at the mouth of the valley. 堤壩 堤坝2. the water kept back. 攔在堤壩裡的水 拦在堤坝里的水 verbpast tense, past participle dammed – (sometimes with up) – to hold back by means of a dam. The river has been dammed up. 築壩攔水 筑坝拦水

dam

水坝zhCN

dam


water under the bridge

A prior issue that is now resolved or considered resolved. That argument we had is just water under the bridge now—don't even worry about it.See also: bridge, water

(as) busy as a beaver (building a new dam)

Very busy, assiduous, or hardworking. The phrase refers to beavers' reputation for being extremely industrious. Between working two part-time jobs, volunteering on the weekends, and looking after his little brother, Sam's been busy as a beaver this summer. I've been as busy as a beaver building a new dam this year. I've had almost no free time!See also: beaver, busy, new

dam up

To block something from flowing freely, typically water in a stream, river, etc. A noun or pronoun can be used between "dam" and "up." If we don't dam up the river, this rain will cause a flood.See also: dam, up

water over the dam

A prior issue or unfortunate past event that is now considered resolved, settled, or forgotten about. That argument we had is just water over the dam now—don't even worry about it. A: "I'm so sorry for bringing up that thing with your father again!" B: "Don't be, that was a long time ago. It's water over the dam."See also: dam, over, water

dam something up

to erect a barrier in a river, stream, brook, etc. We are going to have to dam this stream up to make a pond for the cattle. Let's dam up this stream. Why is this river dammed up?See also: dam, up

water over the dam

 and water under the bridgeFig. past and unchangeable events. Your quarrel with Lena is water over the dam; now you ought to concentrate on getting along with her. George and I were friends once, but that's all water under the bridge now.See also: dam, over, water

water over the dam

Also, water under the bridge. Something that is over and done with, especially an unfortunate occurrence. For example, Last year's problems with delivery are water over the dam, or Never mind that old quarrel; that's water under the bridge. These metaphoric phrases allude to water that has flowed over a spillway or under a bridge and thus is gone forever. The first term was first recorded in 1797; the variant dates from the late 1800s. See also: dam, over, water

water under the bridge

BRITISH, AMERICAN or

water over the dam

AMERICANIf you say that a bad experience is water under the bridge, you mean that it happened a long time ago and so you do not feel upset or worried about it now. He didn't treat me very well at the time but it's all water under the bridge now. Mr Bruce said that he was relieved it was over and that he regarded his time in jail as water under the bridge. Note: You can also say things such as a lot of water has gone under the bridge to mean that a lot of time has passed or a lot of things have happened since a bad experience. It's almost two years since it happened and a lot of water has gone under the bridge. We're now on speaking terms with Marcia.See also: bridge, water

water under the bridge

used to refer to events or situations in the past that are no longer to be regarded as important or a source of concern. The related expression there's been a lot of water under the bridge since — is used to indicate that a lot of time has passed and a great many events have occurred since a particular event. A North American variant is water over the dam .See also: bridge, water

water under the bridge

A past occurrence, especially something unfortunate, that cannot be undone or rectified: All that is now just water under the bridge.See also: bridge, water

water over the dam

Over and done with; past. This term, along with the slightly older water under the bridge, is a metaphor for anything finished and irreversible just as water that has once flowed through a spillway or under a bridge is gone forever. Richard Sale combined both metaphors in Passing Strange (1942): “‘That’s water under the dam.’—‘Bridge,’ I said. ‘Or water over the dam.’”See also: dam, over, water

dam


dam,

barrier, commonly across a watercourse, to hold back water, often forming a reservoir or lake; dams are also sometimes used to control or contain rockslides, mudflows, and the like in regions where these are common. Dams are made of timber, rock, earth, masonry, or concrete or of combinations of these materials. Timber is seldom used in dams because timbers are impermanent and their height is limited. Rock-fill dams consist of an embankment of loose rock with either a core impervious to water (e.g., clay) or a watertight face on the upstream side. Earth dams may be either simple embankments of earth or embankments reinforced with a core of cement or with an upstream surface made watertight. Masonry and concrete dams are either gravity dams or arch dams (either single-arch or multiple-arch). Gravity dams are dependent upon their own weight for resistance to the pressure of the water. Single-arch dams are curved upstream and are usually constructed in narrow canyons or gorges where the rocky side walls are strong enough to withstand the tremendous lateral thrust of the dam that is caused by the pressure of the water. Dams of the multiple-arch type consist of a number of single arches supported by buttresses. Dams may also be constructed with roller-compacted concrete, in which thin layers of concrete are compacted as if they were earth layers; this produces a far stronger dam, without the need for full forms.

Dams have been constructed from early times to provide a ready supply of water for irrigation and other purposes. One of the earliest large dams for this purpose was a marble structure built c.1660 in Rajputana (Rajasthan), India. A dam used only to impound water is often called a barrage; the largest such barrage is the Syncrude Tailings Dam in Canada, which impounds 540 million cubic meters of water.

Most modern dams are constructed for multiple purposes, e.g., to provide for irrigation, to aid flood control and hence improve the navigability of waterways, and especially to furnish power for hydroelectric plants. Notable dams built to provide hydroelectric power include the AswanAswan
or Assuan
, city (1986 pop. 190,579), capital of Aswan governorate, S Egypt, on the Nile River at the First Cataract. It is one of the driest cities in the world.
..... Click the link for more information.
 Dam in Egypt, the Kariba DamKariba Dam
, hydroelectric project, in Kariba Gorge of the Zambezi River, on the Zambia-Zimbabwe border, S central Africa; built 1955–59. One of the world's largest dams, it is 420 ft (128 m) high and 1,900 ft (579 m) long.
..... Click the link for more information.
 in Zambezi, the Daniel Johnson Dam in Canada, the Guri Dam in Venezuela; the Itaipú Dam between Brazil and Paraguay, and the Three Gorges DamThree Gorges Dam,
607 ft (185 m) high and 7,575 ft (2,309 m) long, on the Chang (Yangtze) River, central Hubei prov., China, 30 mi (48 km) W of Yichang. The largest concrete structure in the world, the dam itself was constructed from 1994 to 2006.
..... Click the link for more information.
 in China, which is the largest hydropower dam in the world. The Grand Coulee DamGrand Coulee Dam
, 550 ft (168 m) high and 4,173 ft (1,272 m) long, on the Columbia River, N central Wash., NW of Spokane; built 1933–42 as a key unit in the Columbia basin project of the U.S. Bureau of Reclamation.
..... Click the link for more information.
, located near Spokane, Wash., is the largest hydropower dam in the United States. The 20th cent. witnessed many great dam projects in the United States (see Central Valley projectCentral Valley project,
central Calif., long-term general scheme for the utilization of the water of the Sacramento River basin in the north for the benefit of the farmlands of the San Joaquin Valley in the south, undertaken by the U.S. Bureau of Reclamation in 1935.
..... Click the link for more information.
; Missouri River basin projectMissouri River basin project,
comprehensive plan authorized in 1944 for the coordinated development of water resources of the Missouri River and its tributaries, draining an area of c.
..... Click the link for more information.
; Tennessee Valley AuthorityTennessee Valley Authority
(TVA), independent U.S. government corporate agency, created in 1933 by act of Congress; it is responsible for the integrated development of the Tennessee River basin.
..... Click the link for more information.
). The Oroville DamOroville Dam,
770 ft (235 m) high and 7,600 ft (2,317 m) long, on the Feather River, N Calif., near the city of Oroville. The highest dam in the United States and the largest unit of the Feather River project, the dam was built (1957–68) to provide electric power, drinking
..... Click the link for more information.
, located in California, the tallest in the United States, is 770 ft (235 m) high; the Rogun Dam, in Russia, the tallest in the world, is 1,100 ft (335 m) high. A large dam in Panama forms Gatún LakeGatún Lake
, artificial lake, 163 sq mi (422 sq km), Colón Prov., Panama, formed by the impounding of the Chagres River. Gatún Dam (completed 1912), 1 1-2 mi (2.4 km) long and 115 ft (35 m) high, controls the level of the lake (c.
..... Click the link for more information.
, the key to the Panama Canal system.

Bibliography

See A. H. Cullen, Rivers in Harness: The Story of Dams (1962); N. Smith, A History of Dams (1972); D. Jackson, Great American Bridges and Dams (1988); A. H. J. Dorsey, ed., Large Dams: Learning from the Past, Looking at the Future (1997).

Dam

 

a hydraulic-engineering structure that blocks off a river or other watercourse to raise the water level behind itself, to create a head at its location, and to create a reservoir.

The significance of dams for water management is diverse. The raising of the water level and the increase in depth in the upper pool contribute to navigation and timber flotation, as well as to water retention for the needs of irrigation and water supply. The creation of a head at the dam makes possible the use of the river’s discharge to generate power. The presence of a reservoir makes possible regulation of the discharge, that is, an increase in the water discharge in the river during the low periods and a reduction of maximum discharge during high water, which could otherwise cause destructive flooding. Dams and reservoirs have a substantial effect on rivers and adjacent areas. The river discharge conditions, water temperature, and duration of freeze-up of the river are altered; fish migration is impeded; the shores of the river behind the dam are inundated; and the microclimate of the littoral areas is altered. A dam is usually the main structure of a hydraulic power system.

Dam construction began at the same time as hydraulic engineering, in connection with the significant development of artificial irrigation among the farming peoples of Egypt, India, and China. The erection of dams was necessary for the construction of water-power installations and later of hydroelectric power plants. The use of water resources for energy was the basic incentive for increasing the size and improving the design of dams, as well as for the appearance of hydraulic power systems on numerous rivers.

On the territory of the USSR, water mills with dams were built as early as the time of Kievan Rus’. In the 17th to 19th centuries, the mining, metallurgical, textile, paper, and other industrial sectors in the Urals, the Altai, Karelia, and the central regions of Russia mainly used the mechanical energy of water-power installations. The dams of such installations were insignificant in size and were built of local materials.

The construction of high-capacity hydroelectric power plants with large concrete and earth dams began only under Soviet power, after the adoption of the plan of GOELRO (the State Commission for the Electrification of Russia). The first concrete spillway of the Volkhov Hydroelectric Power Plant was built in 1926, and the high concrete dam of the Dnieper Hydroelectric Power Plant was built in 1932 (its maximum height was about 55 m). The spillway of the Nizhniaia Svir’ Hydroelectric Power Plant was the first dam built on loose clay ground. Dams built in the 1950’s to 1970’s on rivers carrying a great deal of water included hydraulic-fill earth dams on the Volga near Kuibyshev and Volgograd, the concrete dams of the Bratsk Hydroelectric Power Plant on the Angara (height, 128 m) and the Krasnoiarsk Hydroelectric Power Plant on the Enisei (124 m), the 300-m rock-fill dam of the Nurek Hydroelectric Power Plant on the Vakhsh River, and the arch dam of the Saian Hydroelectric Power Plant on the Enisei (height, 242 m; length of crest, 1,070 m; under construction as of 1975). The design and construction of dams in the USSR are on a high technical level, which has enabled Soviet dam construction to occupy a leading place in the world.

Among notable dams built in other countries are the 87-m multiple-arch Bartlett Dam (USA, 1939), the 112-m rock-fill Paradela Dam (Portugal, 1958), the 122-m earth-fill Serre-Pon-çon Dam (France, 1960), the 131-m rock-fill Miboro Dam (Japan, 1961), and the 284-m Grande Dixence concrete gravity dam (Switzerland, 1961).

The type and design of a dam are determined by its size and purpose, as well as by the natural conditions and the type of main building material. Dams are divided by purpose into nonover-flow and overflow types (the latter is designed only to raise the level of the upper pool). In terms of head, dams are divided into low-head, with a head of up to 10 m; medium-head, with a head of 10-40 m; and high-head, with a head of more than 40 m.

A distinction is made among three types of dams, depending on the role performed in the hydraulic power system: (1) the nonoverflow type, which serves only to block the flow of water; (2) the overflow type, which is designed to release excess water and is equipped with surface spillway openings, which may be open or have gates, or with base water outlets; (3) the station type, which has water intakes (with the corresponding equipment) and water lines driving the turbines of a hydroelectric power plant. In terms of the basic material from which dams are constructed, there are earthen, rock-fill, concrete, and wooden dams.

Earth dams are erected completely or partially from impervious soil. Such soil, which is laid on the upstream slope of the dam, forms a cutoff wall; if the soil is placed inside the body of the dam, a core is created. The presence of a cutoff wall or core makes possible the erection of the remaining portion of the dam from permeable soil or from stone (an earth core rock-fill dam). Drainage is provided along the toe of an earth dam to lead off water that seeps through the body and base of the dam. The upstream slope of the dam is protected from wave action by concrete slabs or riprap. In erecting an earthen embankment dam, the soil is mined in a quarry by excavators, transported to the construction site in dump trucks, placed in the body of the dam, leveled out by bulldozers, and packed layer by layer with rollers. The erection of a hydraulic-fill dam includes excavation of the ground with dredges or water jets and the transport of the slurry through pipe and its distribution on the surface of the dam being erected. The water then flows away, and the settling earth stabilizes itself. To prepare the base and erect an earth dam, the foundation pit in the channel of the river is protected by cofferdams, and the river is diverted through previously laid temporary conduits, which are closed after the dam has been erected.

In a rock-fill dam, the cutoff wall or core is made from reinforced concrete, asphalt, wood, metal, or polymer materials. The requirement for low water permeability also extends to the base of the dam. If the ground of the base is permeable to a great depth, it is covered in front of the dam by an upstream apron made, for example, of clay, which forms a single unit with the cutoff wall. A core dam is supplemented by the construction of a steel sheet-pile wall or an antiseepage curtain at the base. The stone in rock-fill and earth core rock-fill dams is laid in very thick layers.

Concrete dams are usually classified according to design features, depending on the shear strain conditions. Three main types of dams are thus differentiated: gravity, arch, and buttress dams. The basic material for modern concrete dams, mainly of the gravity type, is hydraulic-engineering concrete. One of the most important questions in erecting concrete dams is the reduction in water seepage in the base. For this purpose, antiseepage curtains are built at the base of high concrete dams, close to the heel. The base is drained over the remaining area to reduce the water pressure on the toe of the dam; this increases the stability of the structure. To avoid the formation of cracks as a consequence of temperature fluctuations, gravity and buttress dams are divided lengthwise into short sections, and the joints between sections are filled with “waterstops.” To prevent the appearance of cracks as a result of shrinkage of the concrete during hardening, and also to reduce temperature stresses, concrete for dams is poured in individual blocks of limited size. The components of the concrete mix and the concrete placed in the blocks are also cooled by circulation of a cooling agent from a refrigeration unit through a system of pipes laid in the body of the dam. A concrete dam in a riverbed is usually built in two stages under the protection of cofferdams, which block off the pit. During erection of the first stage of the dam, the river flows through a free portion of the bed; in the second stage it flows through openings (passages) left in the dam, which are closed at the end of construction work. If the riverbed is narrow, the concrete dam is built in one stage, with temporary diversion of the river into shore conduits.

The low-head concrete spillway, which is widely used in hydraulic-engineering construction, is erected on a nonrock foundation and is designed to pass large discharges of water. Its basis is the spillway openings formed by a concrete flat apron and buttresses and closed by hydraulic gates. Behind the spillways, massive reinforcement of the channel is provided in the form of an apron, which is sometimes deepened to form a stilling basin, and lighter reinforcement called the downstream apron. Drainage is built under the apron. The spillway is joined to the banks or to earth dams by massive piers. A low-head concrete spillway usually is built with reinforcement, which often extends throughout the structure. To economize on materials, the apron and buttresses of such a dam are sometimes made with a light honeycomb design, in which the spaces are filled with dirt.

Low-head wooden dams of a piling and cribwork design are frequently built in forested regions (usually with spillways).

A special type of water-retaining structure is the sectional navigation dam. To erect such a dam, buttresses of steel beams are set up on a flat apron during the summer low-water period. Bridges are laid along the buttresses, and gates of simple design rest against the buttresses. The dam raises the level of the headwater, and ships and rafts pass through a lock. During the high-water period the gates and bridges are disassembled, and the girders of the buttresses are laid on the apron, opening a channel for ships and rafts across the dam.

A general trend in modern dam construction is the increase in dam height. The heights that have been achieved can be surpassed; however, the construction of two sequentially placed dams of lesser height is often economically more expedient than the use of one tall dam. The improvement in the types of dams from earth materials is being carried out with a simultaneous reduction in cost and acceleration of construction by increasing the capacity of construction and transportation equipment. Lower costs of concrete dams are being achieved through a reduction in the volume of the dams and by replacing gravity dams with buttress dams and by the wider use of arch dams. This trend has been accompanied by an improvement in and specialization of the properties of cement and concrete. The combination of the spillway and power plant building into a single structure is very efficient, since it reduces the concrete part of the upstream surface of the hydraulic power system, which is the most expensive. This problem is solved both by locating the hydraulic power units in the cavity of a tall dam and by building the water intakes in the underwater mass of a low-head power plant.

REFERENCES

Grishin, M. M. Gidrotekhnicheskie sooruzheniia. Moscow, 1968.
Nichiporovich, A. A. Plotiny iz mestnykh materialov. Moscow, 1973.
Moiseev, S. N. Kamenno-zemlianye i kamenno-nabrosnye plotiny. Moscow, 1970.
Grishin, M. M., and N. P. Rozanov. Betonnye plotiny. Moscow, 1975.
Proizvodstvo gidrotekhnicheskikh rabot. Moscow, 1970.

A. L. MOZHEVITINOV

What does it mean when you dream about a dam?

A dam may signify repressed emotional energy. The dreamer may feel like crying, but instead is holding back the tears.

dam

[dam] (civil engineering) A barrier constructed to obstruct the flow of a watercourse. A pair of cast-steel plates with interlocking fingers built over an expansion joint in the road surface of a bridge.

Dam

A barrier or structure across a stream, river, or waterway for the purpose of confining and controlling the flow of water. Dams vary in size from small earth embankments for farm use to high, massive concrete structures for water supply, hydropower, irrigation, navigation, recreation, sedimentation control, and flood control. As such, dams are cornerstones in the water resources development of river basins. Dams are now built to serve several purposes and are therefore known as multipurpose. The construction of a large dam requires the relocation of existing highways, railroads, and utilities from the river valley to elevations above the reservoir. The two principal types of dams are embankment and concrete. Appurtenant structures of dams include spillways, outlet works, and control facilities; they may also include structures related to hydropower and other project purposes. See Electric power generation, Water supply engineering

Dams are built for specific purposes. In ancient times, they were built only for water supply or irrigation. Early in the development of the United States, rivers were a primary means of transportation, and therefore navigation dams with locks were constructed on the major rivers. Dams have become more complex to meet large power demands and other needs of modern countries.

In addition to the standard impounded reservoir and the appurtenant structures of a dam (spillway, outlet works, and control facility), a dam with hydropower requires a powerhouse, penstocks, generators, and switchyard. The inflow of water into the reservoir must be monitored continuously, and the outflow must be controlled to obtain maximum benefits. Under normal operating conditions, the reservoir is controlled by the outlet works, consisting of a large tunnel or conduit at stream level with control gates. Under flood conditions, the reservoir is maintained by both the spillway and outlet works. See Reservoir

All the features of a dam are monitored and operated from a control room. The room contains the necessary monitors, controls, computers, emergency equipment, and communications systems to allow project personnel to operate the dam safely under all conditions. Standby generators and backup communications equipment are necessary to operate the gates and other reservoir controls in case of power failure. Weather conditions, inflow, reservoir level, discharge, and downstream river levels are also monitored. In addition, the control room monitors instrumentation located in the dam and appurtenant features that measures their structural behavior and physical condition.

All dams are designed and constructed to meet specific requirements. First, a dam should be built from locally available materials when possible. Second, the dam must remain stable under all conditions, during construction, and ultimately in operation, both at the normal reservoir operating level and under all flood and drought conditions. Third, the dam and foundation must be sufficiently watertight to control seepage and maintain the desired reservoir level. Finally, it must have sufficient spillway and outlet works capacity as well as freeboard to prevent floodwater from overtopping it.

Dams are classified by the type of material from which they are constructed. In early times, the materials were earth, large stones, and timber, but as technology developed, other materials and construction procedures were used. Most modern dams fall into two categories: embankment and concrete. Embankment dams are earth or rock-fill; other gravity dams and arch and buttress dams are concrete. See Arch, Concrete

The type of dam for a particular site is selected on the basis of technical and economic data and environmental considerations. In the early stages of design, several sites and types are considered. Drill holes and test pits at each site provide soil and rock samples for testing physical properties. In some cases, field pumping tests are performed to evaluate seepage potential. Preliminary designs and cost estimates are prepared and reviewed by hydrologic, hydraulic, geotechnical, and structural engineers, as well as geologists. Environmental quality of the water, ecological systems, and cultural data are also considered in the site-selection process.

Factors that affect the type are topography, geology, foundation conditions, hydrology, earthquakes, and availability of construction materials. The foundation of the dam should be as sound and free of faults as possible. Narrow valleys with shallow sound rock favor concrete dams. Wide valleys with varying rock depths and conditions favor embankment dams. Earth dams are the most common type.

The designers of a dam must consider the stream flow around or through the damsite during construction. Stream flow records provide the information for use in determining the largest flood to divert during the selected construction period. One common practice for diversion involves constructing the permanent outlet works, which may be a conduit or a tunnel in the abutment, along with portions of the dam adjacent to the abutments, in the first construction period. The stream is diverted into the outlet works by a cofferdam high enough to prevent overtopping during construction. A downstream cofferdam is also required to keep the damsite dry. See Cofferdam

Personnel responsible for operation and maintenance of the dam are familiar with the operating instructions and maintenance schedule. A schedule is established for collection and reporting of data for climatic conditions, rainfall, snow cover, stream flows, and water quality of the reservoir, as well as the downstream reaches. All these data are evaluated for use in reservoir regulation. Another schedule is established for the collection of instrumentation data used to determine the structural behavior and physical condition of the dam. These data are evaluated frequently. Routine maintenance and inspection of the dam and appurtenant structures are ongoing processes. The scheduled maintenance is important to preserve the integrity of the mechanical equipment.

The frequency with which instrumentation data are obtained is an extremely important issue and depends on operating conditions. Timely collection and evaluation of data are critical for periods when the loading changes, such as during floods and after earthquakes. Advances in applications of remote sensing to instrumentation have made real-time data collection possible. This is a significant improvement for making dam safety evaluations.

Throughout history there have been instances of dam failure and discharge of stored water, sometimes causing considerable loss of life and great damage to property. Failures have generally involved dams that were designed and constructed to engineering standards acceptable at the time. Most failures have occurred with new dams, within the first five years of operation.

dam

11. a barrier of concrete, earth, etc., built across a river to create a body of water for a hydroelectric power station, domestic water supply, etc. 2. a reservoir of water created by such a barrier

dam

2 the female parent of an animal, esp of domestic livestock

DAM

(Digital Asset Management) Keeping track of the digital assets of an organization. Companies have come to own a huge amount of digitally created material that needs to be stored, cataloged and easily retrieved. See DAMS.

dam


dam

 [dam] 1. a barrier to obstruct the flow of water or other fluid.2. rubber dam.dental dam rubber dam.rubber dam a sheet of thin latex rubber used by dentists to isolate a tooth or teeth from the fluids of the mouth during dental treatment, held in place by a clamp and frame. Occasionally these are used in surgical procedures to isolate tissues or structures. Called also dam.A well-sealed properly inverted rubber dam. From Darby and Walsh, 1994.

DAM

Abbreviation for diacetylmonoxime.

Dam

(dahm), C.P. Henrik, Danish biochemist and Nobel laureate, 1895-1976. See: Dam unit.

dam

(dam), 1. Any barrier to the flow of fluid. 2. In surgery and dentistry, a sheet of thin rubber arranged so as to shut off the operative site from the access of fluid. [A.S. fordemman, to stop up]

dam 1

(dăm)n. A barrier against the passage of liquid or loose material, as a rubber sheet used in dentistry to isolate one or more teeth from the rest of the mouth.
dam′mer n.

dam 2

(dăm)n. A female parent of an animal, especially a domesticated mammal such as a horse.

dam

(dam) 1. Any barrier to the flow of fluid. 2. surgery, dentistry A sheet of thin rubber arranged so as to shut off the part operated upon from the access of fluid. [A.S. fordemman, to stop up]

dam

(dam) 1. Any barrier to the flow of fluid. 2. In surgery and dentistry, sheet of thin rubber arranged to shut off operative site from the access of fluid. [A.S. fordemman, to stop up]

Dam


DAM. A construction of wood, stone, or other materials, made across a stream of water for the purpose of confining it; a mole.
2. The owner of a stream not navigable, may erect a dam across it, and employ the water in any reasonable manner, either for his use or pleasure, so as not to destroy or render useless, materially diminish, or affect the application of the water by the proprietors below on the stream. He must not shut the gates of his dams and detain the water unreasonably, nor let it off in unusual quantities to the annoyance of his neighbors. 4 Dall. 211; 3 Caines, 207; 13 Mass. 420; 3 Pick, 268; 2 N. H. Rep. 532; 17 John. 306; 3 John. Ch. Rep. 282; 3 Rawle, 256; 2 Conn. Rep. 584; 5 Pick. 199; 20 John. 90; 1 Pick. 180; 4 Id. 460; 2 Binn. 475; 14 Serg. & Rawle, 71; Id. 9; 13 John. 212; 1 McCord, 580; 3 N. H. Rep. 321; 1 Halst. R. 1; 3 Kents Com. 354.
3. When one side of the stream is owned by one person and the other by another, neither, without the consent of the other, can build a dam which extends beyond the filum aqua, thread of the river, without committing a trespass. Cro. Eliz. 269; 12 Mass. 211; Ang. on W. C. 14, 104, 141; vide Lois des Bat. P. 1, c. 3, s. 1, a. 3; Poth. Traite du Contrat de Societe, second app. 236; Hill. Ab. Index, h.t.; 7 Cowen, R. 266; 2 Watts, R. 327; 3 Rawle, R. 90; 17 Mass. R. 289; 5 Pick. R. 175; 4 Mass. R. 401. Vide Inundation.

Dam


Dam

A subdivision of the mohar, the currency of Nepal prior to 1932. A dam was equivalent to 1/128 of a mohar.

DAM


AcronymDefinition
DAMDatabase Activity Monitoring
DAMDigital Asset Management
DAMDamage(d)
DAMDenver Art Museum (Denver, CO, USA)
DAMDigital Asset Manager (Documentum)
DAMDepartment of Agriculture and Markets (New York)
DAMDamariscotta (Amtrak station code; Damariscotta, ME)
DAMDocumento de Arrecadação Municipal (Portuguese: Municipal Collection Document; Brazil)
DAMDeutsches Architekturmuseum (German: German Architecture Museum)
DAMData Acquisition Module (various companies)
DAMDifficult Airway Management (medical care)
DAMDraft Amendment
DAMDocuments d'Archéologie Méridionale (French: Journal of Archaeology South)
DAMDestroy All Monsters
DAMDisability Awareness Month
DAMData Augmented Model
DAMData Address Mark
DAMDesktop Agent Manager
DAMDynamic Access Model
DAMDistrict Award of Merit (various organizations)
DAMMothers against Dyslexia (aka Dyslexia against Mothers)
DAMDigital Art Museum
DAMDhaka Ahsania Mission (Bangladesh)
DAMDivisional Ammunition Column
DAMDay Ahead Market (energy market)
DAMDebian Account Manager
DAMDelaware Art Museum (Wilmington, Delaware)
DAMDirection des Applications Militaires (French: Military Applications; French Atomic Energy Commission)
DAMDiego Armando Maradona
DAMDepartamento de Adquisiciones y Mantenimiento (Spanish: Department of Acquisitions and Maintenance; Guatemala)
DAMDépartement Archives et Médiathèque (French: Department of Archives and Media)
DAMDirect Access Method
DAMDeutsche Angelgeräte Manufaktur Int. GmbH (German: German Fishing Tackle Manufacturer Int. Ltd.)
DAMDigital Automatic Music
DAMData Access Manager
DAMDebris Avoidance Maneuver
DAMDog Agility Masters (Canine Agility Tournament)
DAMDrainage Area Map (stormwater management)
DAMDiagnostic Acceptability Measure
DAMDry As Molded (plastics processing)
DAMDistributed Abstract Machine
DAMDeoxyadenosine Methylase
DAMDirect Access Memory
DAMDirect Access Mode
DAMDouble Accumulator Multiplier (computer architecture)
DAMDayton Art Museum (Dayton, OH)
DAMDouble-Aluminized Mylar
DAMData Acquisition & Monitoring
DAMDivorced Asian Male
DAMDesktop Asset Management
DAMData Access Metric
DAMDriver Amplifier Module
DAMDefended Area Model
DAMDynamic Appearance Model
DAMDekameter or Decameter
DAMDisplay Aided Maintenance
DAMData Association Method
DAMDomain Analysis Methodology
DAMDelay Arming Mechanism
DAMDefense Activities Mechanicsburg
DAMDamascus, Syria - Damascus International (Airport Code)
DAMData Acquisition Mainframe
DAMDumb Assed Maneuver
DAMDemande d'Autorisation de Modification (French: Request for Authorization to Change; nuclear energy industry)
DAMDelegation Authorization Model
DAMDirectory & Access Management

dam


  • all
  • noun
  • verb

Synonyms for dam

noun barrier

Synonyms

  • barrier
  • wall
  • barrage
  • obstruction
  • embankment
  • hindrance

verb block up

Synonyms

  • block up
  • block
  • hold in
  • restrict
  • check
  • confine
  • choke
  • hold back
  • barricade
  • obstruct

Synonyms for dam

verb to stop or prevent passage of

Synonyms

  • bar
  • block
  • impede
  • obstruct

Synonyms for dam

noun a barrier constructed to contain the flow of water or to keep out the sea

Synonyms

  • dike
  • dyke

Related Words

  • barrier
  • milldam
  • weir

noun a metric unit of length equal to ten meters

Synonyms

  • decameter
  • decametre
  • dekameter
  • dekametre
  • dkm

Related Words

  • metric linear unit
  • m
  • meter
  • metre
  • hectometer
  • hectometre
  • hm

noun female parent of an animal especially domestic livestock

Related Words

  • female

verb obstruct with, or as if with, a dam

Synonyms

  • dam up

Related Words

  • obturate
  • occlude
  • close up
  • impede
  • obstruct
  • jam
  • block
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