Text                                              Major canals of the world

The Panama and Suez canals are the most important 1) ______in the world. Both of them provide valuable navigation short cuts and have figured prominently in 2) ______affairs and international 3) ______.

The Panama Canal links the Atlantic and 4) ______oceans. It extends from Limon Bay on the Atlantic to the Bay of Panama on the Pacific, a distance of about 51 5) ______(82 kilometers). It is the 6) ______canal in the world. About 12,000 7) ______pass through it annually.

The Panama Canal reduces the sea 8) ______between New York City and San Francisco by more than 7,800 miles (12,600 kilometers). Without the canal, ships 9) ______between the two cities would have to pass around the southern tip of South America. The Panama Canal 10) ______a strategic role during World War 11 (1939-1945) by enabling United States naval forces to move quickly and easily between the Atlantic and Pacific oceans. The Suez Canal extends for about 100 miles (160 kilometers) between Port Said, Egypt, and the Gulf of Suez, an 11) ______of the Red Sea. It allows ships to move 12) ______between the Mediterranean and Red seas and serves as an important water link between Europe and Asia. For example, the canal 13) ______sea voyages between Great Britain and India by about 6,000 miles (9,700 kilometers). Without the canal, ships traveling between the two countries would have to pass around the southern coast of Africa. The Suez Canal was 14) ______by sunken ships in 1967, during the Arab-Israeli War, and 15) ______traffic between Asia and Europe was disrupted. Egypt 16) ______the canal in 1975.

Major canals in the United States and Canada 17) ______the Soo Canals, the Chicago Sanitary and Ship Canal, and the All-American Canal. Canals also form an important part of the St. Lawrence Seaway and other major waterways.

The Soo Canals, on the United States-Canadian border, 18) ______Lakes Superior and Huron. The Chicago Sanitary and Ship Canal 19) ______ships to travel between Lake Michigan and the Mississippi River via the Chicago, Des Plaines, and Illinois rivers. The All-American Waterway, in southern California, carries water from the Colorado River to the Imperial and Coachella valleys, important 20) ______areas.

The St. Lawrence Seaway 21) ______of a system of canals and locks, the St. Lawrence River, and several lakes. It extends for about 450 miles (724 kilometers) from the eastern end of Lake Erie to Montreal, Que., and includes the Welland Ship Canal. It links the 22) ______Lakes and the Atlantic Ocean.

Major canals in other countriesinclude the Grand Canal in 23) ______and several canals in Russia and in Western Europe. The Grand Canal is a system of canals and navigable sections of the Yangtze and Huai rivers and the Huang He (Yellow River). It 24) ______more than 1,000 miles (1,600 kilometers) through China. It is the world's longest artificially 25) ______waterway.

In 26) ______, a system of canals links the 27) ______River with the 28) ______Ocean, the Baltic Sea, the Don River, and Moscow. Major rivers in Western Europe are also connected by many canals, 29) ______the Amsterdam-Rhine Canal in the Netherlands and the Albert Canal and Charleroi-Brussels Canal in Belgium. The Kiel Canal in 30) ______connects the Baltic and the North seas.

Translate the following text from Russian into English.

1) Августовский канал находится в Гродненском районе Беларуси и Сувалковском воеводстве Польши. Соединяет реки Неман и Бебжа. Длина 102 км, на территории Беларуси – 22 км. Средняя глубина 1,8 метра. Создан из системы каналов, озер (Нецка, Белое на территории Польши), прудов, участков рек и проток между озерами. На территории Беларуси включает в себя часть реки Черная Ганьча (длина 9 км), а также отдельное русло (длина 7 км), которое соединяет эту реку с Неманом. Имеет 18 шлюзов, из них 4 на территории Беларуси. Построен в 1824-39 годах как водный путь для перевозки грузов из бассейна Вислы и Неман к Балтийскому морю.

2) Гидротехнические особенности. Августовский канал строили весьма добротно, учитывая все достижения науки. Так, стены канала были посажены на свайное поле из сосновых свай диаметром 40 сантиметров. Дно, в зависимости от грунтов основания, выполнено в виде бетонных выгнутых перекрытий или деревянных на свайном поле. Ворота шлюзов изготавливались из дуба с железными оковами. Для удержания уровня воды имелось 29 плотин шириной от 1,64 до 18,56 метров, изготовленных аналогично шлюзам. Заслонки плотин приводились в движение вручную при помощи зубчатых колес.

Стены камер шлюзов выкладывались из полевых валунов и облицовывались красным кирпичом на растворе и гидролизной извести. Элементы, подвергавшиеся наибольшим нагрузкам (устои, пороги, верхние обрезы шлюзовых камер), облицовывались блоками из песчаника.

Согласно проекту, поперечный профиль русла выполнялся в виде трапеции с шириной дна 9 метров, на уровне воды - 12 метров и с глубиной до 1,5 метра.

Берега канала из сыпучих песков усиливались слоем песка, смешанного с глиной, и засеивались травой. Иногда укладывались куски дерна. С целью усиления берега вдоль всего водного пути высаживались деревья, они же служили защитой от ветра.

Одновременно со строительством канала вдоль него прокладывались буксирные дороги шириной около 4 метров. Они не имели твердого покрытия.

На протяжении канала было сооружено 29 водопропускных плотин, 18 шлюзов, 21 камера, 14 мостов (в большей части - деревянных «журавлиного» типа) и 65 мостиков на буксировочных путях, 24 объекта для обслуживания канала (сейчас на территории Беларуси находятся четыре шлюза, в том числе и самый большой - Немново).

3) Шлюз «Домбровка», построенный в 1828-29 годах по проекту Игнатия Прондзинского находится на 92-м километре канала. В комплекс этого гидротехнического сооружения входит судоходный шлюз и шлюз-регулятор.

Перепад воды в нем составляет 310 сантиметров. По сравнению, скажем, с «Немново» - немного, и шлюзование судов в «Домбровке» длится около 15 минут.

Сам шлюз - это двое массивных ворот. Над шлюзом - разводной, на цепях, мост: чтобы переходить через шлюз, если мост опущен, либо пропускать корабли, если мост поднят.

Read the text again and make notes under the following headings. Then use your notes to talk about intakes.

1) Types of canals.

2) Planning and building a canal.

3) Canal locks.

4) Famous canals.

UNIT IX                       IRRIGATION

Match the terms with their definitions.

Find the translation of the following terms and memorize their meaning.

Read the text to get the gist of it. Answer the following questions.

a) What are the main sources of fresh water?

b) May irrigation water be lost before it reaches the crop?

c) What is transpiration?

Text A                                                                               

Irrigation is the watering of land by artificial methods. It provides water for plant growth in areas that have long periods of little or no rainfall. The water used for irrigation is taken from lakes, rivers, streams, and wells.

Irrigation is used chiefly in three types of climates: in desert regions (such as Egypt and the Southwestern United States), in regions with seasonal rainfall (such as California and Italy),and in moist regions (such as the Eastern United States and Western Europe). The amount of water needed for farming varies with the type of crop and the climate. For example, rice requires more water than does cotton. Any farmland must receive enough water to allow both for plant growth and for the evaporation of water from the soil.

In some countries, more water is used for irrigation than for any other purpose. For example, irrigation accounts for about 40 per cent of the water used in the United States.

Irrigation requires large supplies of fresh (unsalty) water. The two main sources of fresh water are surface water and ground water.

Irrigation requires a method of transporting water from the supply source to a farm. Most farms obtain surface water by means of a network of canals. A large canal carries the water from the supply source to smaller canals called laterals. The laterals are connected to ditches that take the water to the crops. If a farm lies at a lower elevation than the supply source, the water flows to the canals by gravity. If the farm lies at a higher elevation than the source, the water must be pumped up to the canals.

Ground water is pumped to the surface from wells dug below the water table, the top of an aquifer. If possible, an irrigation well is dug on or near the farm it serves. The pump in the well lifts the water into a ditch or pipe that carries it to the crops. If the well is far from the farm, a system of canals or pipes is needed to bring the water to the crops.

Irrigation water may be lost before it reaches crops. For example, reservoirs lose water through evaporation. The greater the surface area of the reservoir, the more water is lost. The amount of water lost through evaporation can be reduced by building deep reservoirs that have small surface areas.

In regions with porous soils, water may be lost through seepage. Seepage occurs when water leaks from the bottom or sides of reservoirs and irrigation channels. Seepage from reservoirs can be controlled by lining a reservoir with a layer of fine soil that water does not easily penetrate. Engineers try to build reservoirs in places where the soil does not allow much seepage. Seepage from irrigation channels can be prevented by lining the canals or streams with a watertight material, such as asphalt or concrete.

Evaporation of water through the leaves of plants is called transpiration. Plants absorb water through their roots and lose it through transpiration. The transpiration of weeds growing in or near irrigation channels may cause great loss of water. Some loss from transpiration can be avoided by lining the channels with a watertight material to prevent weed growth along the channels.