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ПОСОБИЕ (гидротехнич строительство) 174.doc
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5. Decide whether the following sentences are true or false according to the text.

  1. Canals haven’t served as important means of transporting goods and water for thousands of years.

  2. Navigation canals enable vessels to travel between bodies of water.

  3. Irrigation canals and drainage canals are included in water conveyance canals.

  4. Navigation canals may link two different waterways.

  5. Canalized rivers are rivers whose navigable stretches are connected by a series of dams and locks.

  6. Early canals were narrower than modern ones.

  7. Builders consider the kinds of goods to be shipped in and out of an area.

  8. Engineers don’t regard how a canal will affect surrounding plant and animal life.

  9. The digging and moving of earth and rock is the first step in the construction of a canal.

  10. All canals are lined with asphalt or concrete.

  11. Some locks have watertight gates at each end.

  12. Water flows in and out of locks by gravity.

  13. Locks require a supply of water at the upper level of the canal.

6. Finish the following sentences according to the text.

  1. Canal is a waterway dug across …

  2. There are two major types of canals…

  3. Navigation canals may connect …

  4. Many navigation canals are parts of …

  5. When planning a canal, builders first decide whether …

  6. Canals are usually used for …

  7. Engineers determine the course of a canal and decide whether it will need …

  8. The construction of a canal primarily involves …

  9. Canal locks are rectangular chambers that enable ships to move …

  10. Most locks are made of …

  11. Locks are used to overcome …

  12. The flow of water is carefully controlled to prevent the ship from …

7. Answer the following questions.

  1. What is a canal?

  2. Have canals served as important means of transporting goods and water?

  3. What are two major types of canals?

  4. What are navigation canals used for?

  5. What are water conveyance canals used for?

  6. What may navigation canals connect?

  7. What structures enable vessels to travel an entire river by avoiding waterfalls, shallow areas, and other navigation hazards?

  8. What do builders decide and consider?

  9. What are canals usually used for?

  10. When are canals cheaper than railroads or trucks?

  11. Why do engineers study the terrain?

  12. What does the width and depth of a canal based on?

  13. What do water conveyance canals have to allow for animal migration?

  14. What materials may be added to a canal to reduce leakage and prevent erosion?

  15. What are canal locks used for?

  16. Most locks are made of concrete, aren’t they?

  17. Why do some locks have special reservoirs and auxiliary canals?

  18. What is it necessary to do in order to move a vessel upstream where the water level is higher?

  19. What should be done to move a ship downstream?

8. Divide the text into the parts according to the following plan.

a) Types of canals.

b) Planning and building a canal.

c) Canal locks.