水利水電工程專業(yè)英語——灌溉與排水篇

1、精選優(yōu)質文檔-傾情為你奉上水利水電工程專業(yè)英語灌溉與排水篇1. Consumptive Use of Water1. 消耗性用水Consumptive use of water involves problems of water supply, both surface and underground, as well as problems of management and economics of irrigation projects. Consumptive use has become a highly important factor in the arbitration of

2、 controversies over major stream systems where the public welfare of valleys, states, and nations is involved. Before available water resources of a drainage basin in arid and semiarid regions can be satisfactorily ascertained, careful consideration must be given to consumptive use requirements for

3、water in various subbasins.消耗性用水涉及到地表和地下供水問題，也包括管理和灌溉工程的經(jīng)濟性問題。消耗性使用已經(jīng)成為一個評判包含河谷、州和國家公共福利的主要河流系統(tǒng)爭議的重要因素。在干旱和半干旱地區(qū)流域的可利用水資源被確定之前，必須仔細考慮各個子流域內對消耗性用水的需求。1.1 Definition of Consumptive Use1.1 消耗性用水的定義Consumptive use, or evapotranspiration, is the sum of two terms: (1) transpiration, which is water enterin

4、g plant roots and used to build plant tissue or being passed through leaves of plant into the atmosphere, (2) evaporation, which is water evaporation from adjacent soil, water surfaces, or from the surfaces of leaves of the plant. Water deposited by dew, rainfall, or sprinkler irrigation and subsequ

5、ently evaporating without entering the plant system is part of consumptive use.消耗性用水，或者說騰發(fā)量，是兩項的總和：（1）蒸騰，即水分進入植物的根系用來構建植物體或者通過植物葉片被傳輸?shù)酱髿庵校唬?）蒸發(fā)，即水分從鄰近的土壤、水面或者從植物葉面蒸發(fā)的過程。通過露水、降雨或者噴灌儲存，隨后未經(jīng)過植物體而蒸發(fā)也是消耗性用水的一部分。Consumptive use can apply to water requirements of a crop, a field, a farm, a project, or a va

6、lley. When the consumptive use of the crop is known, the water use of larger units can be calculated. Hence, the term “consumptive use” and the following discussion generally refer to the crop.消耗性用水可以應用到一棵植物、一塊土地、一片農場、一個項目或者一個河谷的用水需求中。當作物的消耗性用水為已知時，就可以計算更大單元的用水量。因此，術語“消耗性用水”和接下來的討論主要是指作物。1.2 Conditi

7、ons Affecting Consumptive Use of Water1.2 影響消費性用水的條件Evaportranspiration is influenced by temperature, irrigation practices, length of growing season, precipitation, and other factors. The volume of water transpired by plants depends in part on the water at their disposal, and also on temperature and

8、 humidity of the air, wind movement, intensity and duration of sunlight, stage of development of the plant, type of foliage, and mature of the leaves.騰發(fā)量受到天氣、灌溉方式、生長期長度、降水及其他因素影響。植物蒸騰的水量部分取決于其所處位置的水源，還有溫度和空氣的濕度、風運動、光照的強度和持續(xù)時間、植物生育階段、葉片類型和葉片成熟度。Consumptive use by native vegetation of noncropped land

9、is fairly constant from year to year where the water supply is adequate, but surface evaporation increases in wet years because of the expansion of water surface and moist soil areas. In some irrigated valleys irrigation is lavish when the water supply is abundant, and increased waste water and retu

10、rn flow are consequently available for nonproductive consumption. Also, evaporation is increased from the cropped land soils. Plant diseases and pests reduce consumptive use by inhibiting plant growth. Size of a farm may affect water usage appreciably since borders, size of stream, and crop rotation

11、s may be different.原生植物的消耗性用水在水分供應充足地區(qū)每年是相當恒定的，但是在豐水年地表蒸發(fā)量卻因為水面積和濕潤土壤面積的擴大而增加。在一些灌溉河谷，當供水充足時灌溉是奢侈的，而且增加了廢水量，因而回水可被用作非生產(chǎn)性耗水。并且，耕作區(qū)土壤的蒸發(fā)量也會增加。植物病蟲害通過抑制植物的生長減少了消耗性用水。農場的大小可能會顯著地影響水資源利用，因為邊界、河流大小和植物輪作可能是不同的。1) Evapotraspiration from soils. Where the water table is near the ground surface, evaporation fr

12、om the soil is almost equal to evaporation from a free water surface; whereas, with water levels at greater depths below the surface, evaporation from soil decreases until it becomes negligible when moisture no longer reaches the surface by capillary action.1）土壤處的騰發(fā)。在地下水水位接近地表的地方，土壤蒸發(fā)量幾乎與自由水面的蒸發(fā)量相同。

13、而隨著水位降低到距離地表更深處，土壤蒸發(fā)量就會隨之減少，直到當水分不再能通過毛細作用到達地表時它便可以忽略不計。Where irrigation water is applied by flooding methods, large amounts of water are lost by direct evaporation from soil surfaces without having passed through the roots, stems, and leaves of plants. After light showers during the growing season,

14、 considerable rainfall, if not all, is retained on the leaves where it subsequently evaporates without entering the roots of the plants. Showers of less than 5 millimeters seldom enter the soil to a sufficient depth to be used by the plants. Therefore, water received from light rain showers or from

15、light sprinkler irrigation may not be used by the plants in the transpiration process. Subsequent discussion based upon the energy available for evaporation shows, however, that under normal conditions, water that evaporates directly from the soil or leaves is beneficially used, reducing by a like a

16、mount water that would otherwise have been transpired by the plants. This is true provided a normal mature crop exists over the soil surface. Early or late in the growing period, when the crop is not transpiring much water, evaporation from a wet soil surface may exceed normal consumptive use.當灌溉水是通

17、過漫灌的方式引入的時候，大量的水就會直接從土壤表面蒸發(fā)，而沒有經(jīng)過植物的根、莖和葉。在生長季節(jié)的小陣雨過后，至少相當部分的降雨被截留在葉面上并且隨后從那里蒸發(fā)，并未經(jīng)過植物的根系。小于5mm的降雨幾乎不能進入到足夠的深度而被植物利用。因此，從小陣雨或從輕微的噴灌中獲得的水分可能不會被植物用到蒸騰過程中?；谡舭l(fā)使用能量的角度考慮的論述表明，盡管在正常情況下，直接從土壤和葉面蒸發(fā)的水分得到了充分的利用，這些水若不被蒸發(fā)則會被植物用作蒸騰。這真正地在土壤表面養(yǎng)活了一顆正常成熟的作物。在生長周期的早期或晚期，當作物蒸騰量不大時，從濕潤土壤表面的蒸發(fā)可能會超過正常的消耗性用水。There are st

18、ill decided differences in opinion on the effect of cultivation on direct evaporation of water from soils. Recent studies seem to throw considerable doubt on advantages of soil mulches for conserving water through reduction of evaporation losses from soils that are not excessively wet or in contrast

19、 with a water table at a shallow depth. Therefore, broad general conclusions concerning influence of cultivation on direct evaporation losses from soils may be misleading. The large number of variable factors involved-notably the differences in distances to free-water sources, in original moisture c

20、ontent of unsaturated soils, in texture, structure, and water conductivity- make it hazardous to generalize.人們對于耕種對水分直接從土壤蒸發(fā)效果的看法存在著明顯的差異。最近的研究似乎對于減少并非充分濕潤或者地下水位相對較淺的土壤的蒸發(fā)損失以涵養(yǎng)水分的土壤覆蓋的優(yōu)勢提出了相當大的疑問。因此，關于耕種對于從土壤的直接蒸發(fā)損失影響的結論可能是有誤的。這其中包含著大量的變量因素使之不能一概而論，特別是到自由水源距離的差別、飽和土壤的水分含量、質地、結構以及導水性。2) Transpiration

21、. The process by which water vapor escapes from living plants, principally the leaves, and enters the atmosphere is known as transpiration. During the growing period of a crop, there is a continuous movement of water from the soil into roots, up stems, and out of leaves of the plants. Velocity of wa

22、ter flowing through plants varies widely from 25 to 175 centimeters per hour; but, under conditions of unusually high temperature, dry atmosphere, and wind, velocity of the stream may be greatly increased. A very small proportion of water absorbed by the roots is retained in the plants. If the rate

23、of evaporation at the leaves exceeds the rate of absorption by the roots, wilt occurs and growth of the plant is impeded. On the other hand the available water is not used efficiently, if conditions are such as to stimulate excessive transpiration.2）蒸騰。即水蒸氣通過活體植物溢出，主要是葉子，進入到大氣中的過程被稱為蒸騰。在作物生長階段，存在一個連

24、續(xù)不斷的從土壤進入植物的根系、上升到莖，然后從葉面溢出的水分運動。水分在植物體內流動的速度廣泛地分布于每小時25到175厘米之間；但是，在非正常高溫、干燥的大氣、風等條件下，水流的速度可能會明顯增加。根系吸收的非常小的比例的水分被保留在植物中。如果葉面的蒸發(fā)速率超過了根系的吸水速率，那么植物就會枯萎且其生長受到抑制。另一方面，在刺激過度蒸騰的條件下，可利用水并不能被有效利用。When water changes from liquid to vapor and passed from the plants into the atmosphere, about 590 calories of h

25、eat are required for every cubic centimeter being converted from liquid to vapor. Hence, if heat is not available, transpiration ceases; and conversely, as available heat increases, transpiration increases. Heat can come from the soil, the plant, the air, or from direct radiation. The majority of he

26、at used for transpiration, even over short periods of time, comes directly from the sun as radiant energy.當水分從液態(tài)變成氣態(tài)并從植物進入到大氣中，每立方厘米的水分從液態(tài)轉變成氣態(tài)大約需要590卡路里的熱量。因此，如果沒有熱量可用，蒸騰就會停止；反之，如果可用熱量增加，蒸騰作用增加。熱量可以來自土壤、植物、空氣或者來自直接輻射。用于蒸騰的絕大部分熱量，即使時間很短，直接來自太陽的輻射能量。Thus, a given increment of heat will vaporize a giv

27、en quantity of water. If the available heat is used for vaporizing water from the ground surface, it is not available for vaporizing water within the cavities of the leaf. Therefore, a light shower of rain remaining on the surface of leaves or on the ground can evaporate, utilizing the bulk of avail

28、able energy. When this occurs, the transpiration of water through the plant will be reduced accordingly.因此，一定的增加的熱量會汽化一定量的水分。如果可用的熱量被用來汽化地表的水分，它就不會被利用于葉片氣孔處的水分汽化。因此，小陣雨中留存在葉片表面或是地表的水分會利用大量可用的能量。當這種情況發(fā)生時，通過植物體的蒸騰作用就會相應地被減少。For example, suppose a rainfall of only 3 millimeters occurred during the dry

29、season and all the moisture was intercepted by leaves of the growing crop. Assume also that daily consumptive use was 6 millimeters per day. Experiments show that the bulk of consumptive use occurs during the day. Therefore, if consumptive use of 6 millimeters per day occurs over, say 12 hours, the

30、average use per hour would be 0.5 millimeters. During midday, the rate is likely to nearly double the average or 1.0 millimeters per hour. Hence, in 3 hours the rainfall of 3 millimeters would be evaporated and would have been fully utilized. Often overlooked is the fact that rainfall of 3 millimete

31、rs may represent only one-half of a normal daily consumptive use. Observations of the recovery of a wilted crop following a light shower will show that the rainfall is not without effect. 例如，假設在干旱季節(jié)發(fā)生了一場僅有3mm的降雨，并且所有的水分都被生長中的作物葉片截留。葉舌每天消耗性用水為6mm。試驗表明大量的消耗性用水發(fā)生在白天。因此，如果每天的6mm，消耗性用水發(fā)生在，比如說12小時內，那么每小時平

32、均用水量就是0.5mm。在中午，速率很可能達到平均水平的兩倍即每小時1.0mm。因此，在3個小時內3mm的降水就會被蒸發(fā)并被完全利用。經(jīng)常被忽視的事實是，3毫米的雨量可能只占正常日消耗性用水的一半。對于枯萎的植物在一場小陣雨過后恢復的觀察表明，降雨并非沒有影響。Rainfall of less than 1 centimeter have frequently been neglected in project planning on the erroneous assumption that rain must get into the root zone to be fully effec

33、tive. When the crop covers the ground surface, a light rain or a light irrigation will reduce by a like amount moisture removed from the soil by the roots, provided of course that an excessive wind does not exist.基于雨水必須進入到植物根系區(qū)才能完全有效的假設，小于1厘米的降雨通常在項目規(guī)劃中被忽略。當作物覆蓋地表時，一場小雨或是少量的灌溉會全部通過根系從土壤中吸收走，前提當然是沒有太

34、大的風。2. Irrigation2. 灌溉Irrigation is an ancient agricultural practice that was used 7000 years ago in Mesopotamia, other ancient, notable irrigation systems were located in Egypt, China, Mexico, and Peru. Today, approximately 11 percent of the worlds cropland is irrigated. Some of the densest populat

35、ions are supported by producing crops on irrigated land, as in the United Arab Republic (Egypt), where 100 percent of the cropland is irrigated. This land is located along the Nile River. More than 12 percent of the cropland, or about hectares( acres) are irrigated in the United States. Irrigation i

36、s extremely important in increasing soil productivity throughout the world.灌溉作為一種古老的農業(yè)實踐，最早是用在7000年前的美索不達米亞，同樣古老的著名的灌溉系統(tǒng)位于埃及、中國、墨西哥和秘魯。今天，全世界大約11%的農田可灌溉。一些最密集的人口是由可灌溉徒弟的作物生產(chǎn)所支撐，比如阿拉伯聯(lián)合共和國（即埃及），那里100%的農田可灌溉。這片土地位于尼羅河沿岸。在美國有超過12%的農田，或者大約公頃（英畝）可以灌溉。灌溉對在全世界范圍內提升土壤生產(chǎn)力是極其重要的。2.1 Water Sources2.1 水源Most ir

37、rigation water is surface water resulting from rain and melting snow. Many rivers in the world have their headwaters in mountains and flow through arid and semiarid regions where the water is diverted for irrigation. Examples include the Indus River, which starts in the Himalaya Mountains，and the nu

38、merous rivers on the western slope the Andes Mountains, which flow through the deserts of Chile and Peru to the Pacific Ocean. Much of the water in these rivers comes from the melting of snow in the high mountains. In fact, the extent of the snowpack is measured in order to predict the stream flow a

39、nd amount of water that will be available for irrigation the next season. Many farmers who use well water have their own source of irrigation water. About 20 percent of the water used for irrigation in the United States comes from wells.大部分的灌溉水是來自降雨和融雪的地表水。世界上的很多河流發(fā)源于山區(qū)，流經(jīng)干旱和半干旱地區(qū)，在那里河水被引用灌溉。眾多例子中包括

40、印度河，發(fā)源于喜馬拉雅山脈，且在安第斯山脈西麓有著眾多的河流，穿過智利沙漠和秘魯注入太平洋。這些河流的很多水來自高山上的融雪。事實上，積雪的范圍要被測量以預測河流流量和下一季可以用于灌溉的水量。很多用井水的農民有他們自己的灌溉水源。在美國大約20%的灌溉水來自井水。2.2 Important Properties of Irrigated Soils2.2灌溉土壤的重要性質Soils well suited for irrigation have an intermediate texture to a depth of 1 to 2 meters and without compact or

41、 water-impermeable layers. Loamy soils that are underlain by coarse sands and gravel have greater retention of water in the overlying soil than soils that are loamy-textured throughout. The texture, together with the structure, should result in an infiltration rate of about 0.5 to 8 centimeters per

42、hour and a moderate water-storage capacity. The soil should not have an injurious soluble salt content.非常適合灌溉的土壤要有一個中等的質地，深度在1到2米，并且沒有密實或不透水層。下層為粗砂和礫石的壤質土中覆蓋土層比所有土層都是壤土質地要有更強的保水性。這種質地和結構應該能夠得到每小時0.5到8厘米入滲率保持在和一個適中的儲水能力。土壤中的可溶性鹽含量不應達到有損害性的值。2.3 Water Application Methods2.3 灌水方法Choice of various metho

43、ds of applying irrigation water is influenced by a consideration of : (1) infiltration rate, (2) slope and general nature of the soil surface, (3)supply of water and how it is delivered, (4)crop rotation, and (5) seasonal rainfall. The methods of distributing water can be classified as flood, furrow

44、, subsurface, sprinkler, and drip or trickle.對于眾多灌溉水施用方法的選擇要受到以下思考的影響：（1）入滲速率；（2）坡度和土壤表面一般性質；（3）供水及引水方式；（4）輪作方式；（5）季節(jié)性降雨。配水方法可以分為漫灌、溝灌、地下灌、噴灌和滴灌。1) Flood Irrigation. Flood irrigation floods the land by distributing water by gravity. Water is let into the upper end of the field, usually from a large

45、ditch. Sometimes the water is distributed into basins, which is a common practice for orchards, pastures, and some grain crops, including rice. Flood irrigation can easily over-water some parts of a field while leaving some parts underirrigated.1）漫灌。漫灌就是淹過地塊通過重力分配水。通常水從一個大的溝渠中引入田塊的高處。有時將水分配到低地，這是果園、

46、牧場及一些谷類作物，包括水稻的普遍做法。漫灌的方式很容易讓某些部分灌水過多而另一些部分則沒有灌水。2) Furrow Irrigation. Furrow irrigation is similar to flood irrigation, the difference being that the water distribution is down furrows instead of being allowed to flood over the land. In furrow irrigation, which is used for row crops, water is distr

47、ibuted down between the rows. Furrows that have a slight grade or slope are made across the field. The slope of the furrow bottoms depends on soil infiltration rate, which should be sufficient to distribute water along the entire length of the furrow. Furrow irrigation is unsatisfactory on sand soil

48、s, because of the very high infiltration rate and limited distance of water flow down the furrows.2）溝灌。溝灌與漫灌相類似，其區(qū)別是水沿著壟溝分配而不是要淹過整塊土地。在用于行栽作物的溝灌中，水順著行間分配。整塊田塊中整理出了較小的等級或坡度的壟溝。溝底的坡度取決于土壤入滲速率，它應該足夠水分沿著壟溝長度的方向分配水。溝灌不適合沙土地，因為其入滲速率非常高并且水沿著壟溝流動的距離有限。Many methods are used to distribute water into the furro

49、ws. A major advantage of flood and furrow irrigation is that the water is distributed by gravity, so water distribution costs tent to be low.有很多方法被用于將水分配到溝中。漫灌和溝灌的一個主要的優(yōu)點是水是通過重力分配的，所以配水的成本就會低。3) Sprinkler Irrigation. Sprinkler are widely used to irrigate lawns. Sprinkler systems are versatile and ha

50、ve some special advantages. On sands, where high infiltration rates permit water to flow only a short distance down a furrow, sprinklers are essential to spread water uniformly over the field. On an uneven land surface, expensive land leveling and grading can be avoided by the use of sprinklers. The

51、 portable nature of many sprinkler systems makes them ideally suited for use where irrigation is used to supplement natural rainfall. When connected to soil water-measuring apparati, sprinkler systems can be made automatic.3）噴灌。噴灌在灌溉草坪中應用廣泛。噴灌系統(tǒng)很靈活并且有一些特點。在沙土地，入滲速率只允許水分沿著壟溝在很小的一段距離上流動，噴灌對于將水均勻地在田地上散

52、布是必不可少的。在一個不平整的地表，通過使用噴灌可以避免昂貴的土地平整和分級。噴灌系統(tǒng)的便攜性讓它們非常適用于灌溉被用于補充自然降水的地方。當與土壤水分測量儀器連接時，噴灌系統(tǒng)可以實現(xiàn)自動化。Large self-propelled sprinkler systems, which pivot in a large circle around a well, have become popular. Such systems can irrigate most of the land in a quarter section (160 acres, or 65 hectares). In th

53、e western part of the United States, large green circular irrigated areas produced by pivot sprinklers are clearly visible from the air. The use on many rolling and sandy soils has greatly increased the production of corn and other grain crops on the Great Plains. In some areas, however, underground

54、 water reservoirs are being depleted, and some irrigated areas are again being used as grazing land and for fallowed wheat production.在一個圍繞著一口井的大圈中轉動的大型自走式噴灌系統(tǒng)已經(jīng)流行開來。這樣的系統(tǒng)能夠在一刻鐘的時間內灌溉大部分的土地（160英畝，或65公頃）。在美國西部，由支軸噴灌機制造的大片圓形灌溉區(qū)域在空中都清晰可見。其在大平原地區(qū)很多滾動和沙土地上的應用已經(jīng)極大地增加了玉米和其他糧食作物的產(chǎn)量。然而在一些地區(qū)，地下水庫正在枯竭，一些灌溉地區(qū)有被

55、用作牧場和休耕小麥產(chǎn)量。Sprinkler irrigation modifies the environment by completely wetting plant leaves and the soil surface and by affecting the surrounding air temperature. The high specific heat of water makes sprinkling an effective means of reducing frost hazard. Sprinkler irrigation has been used for fro

56、st protection in such diverse situations as for winter vegetables in Florida, strawberries in Michigan, and citrus in California.噴灌通過使植物葉片和土壤地表完全濕潤以及影響周圍空氣溫度來改善環(huán)境。水的高比熱讓噴灌成為一個減少霜凍損害的有效手段。噴灌已經(jīng)被用作霜凍防護，各種不同的情況包括在冬季里弗羅里達的蔬菜、密歇根州的草莓和加利福尼亞的橘柑。4) Subsurface Irrigation. Subirrigation is irrigating by water

57、movement upward from a water table located some distance below the soil surface. Some areas are naturally subirrigated where water tables are within a meter or two of the soil surface. This occurs in the poorly drained areas of the Sandhills in north-central Nebraska. Artificial subirrigation is pra

58、cticed in the Netherlands, where subsurface drainage lines are used to drain soils in the wet season and then used during drought for subirrigation. The subirrigation depends on the use of drainage ditches and pumps to create and control a water table. Subirrigation works well on the nearly level Fl

59、orida coastal plains. The sandy soils have high saturated hydraulic conductivity, and the natural water table is 1 meter or less from the soil surface much of the time.4）地下灌溉。地下灌溉是通過水從土壤表面以下某段距離內的水位向上運動而進行灌溉。一些地下水位在土壤表面以下一兩米內的地區(qū)能夠進行自然地下灌溉。這種情況發(fā)生在內布拉斯加中北部的Sandhills排水不良的地區(qū)。人工地下灌溉在芬蘭進行了實踐，那里地下排水管線在雨季被用來排出土壤水分，然后在旱季被用來進行地下灌溉。地下灌溉依賴于排水溝和水泵來形成和控制地下水位。地下灌溉在弗羅里達州沿海平原運行良好。沙質土壤具有較高的飽和水力傳導度，其自然水位大部分時