II. Look at the words below. Which word is the odd one?

1. a) aeration b) coagulation c) disinfectant d) softening

2. a) distillation b) distribution c) filtration d) crystallization

3. a) gasoline b) wastewater c) groundwater d) seawater

4. a) transporting b) distribution c) supplying d) treatment

5. a) oil b) cement c) steel d) concrete

6. a) reservoir b) box c) cistern d) tank

7. a) to freeze b) to evaporate c) to illuminate d) to thaw

 

 

III. Answer the following questions:

1. How is water usually delivered, by what means?

2. What ways of treatment does the water work usually employ?

3. What does usually reduce unpleasant odours and tastes in water?

4. What plants are constructed in places where there is no fresh water?

5. What happens after water treatment?

6. What materials are used for transporting water?

7. Why do we pay for water usage?

 

Dam

Dam structure built across a stream, river, or estuary to retain water. Its purposes are to meet demands for water for human consumption, irrigation, or industry; to reduce peak discharge of floodwater; to increase available water stored for generating hydroelectric power; or to increase the depth of water in a river so as to improve navigation. An incidental purpose can be to provide a lake for recreation.

Auxiliary works at a dam may include spillways, gates, or valves to control the discharge of surplus water downstream from the dam; an intake structure conducting water to a power station or to canals, tunnels, or pipelines for more distant use; provision for evacuating silt carried into the reservoir; and means for permitting ships or fish to pass the dam. A dam therefore is the central structure in a multipurpose scheme aiming at the conservation of water resources. The multipurpose dam holds special importance in less developed countries, where a small nation may reap enormous benefits in agriculture and industry from a single dam.

Dams fall into several distinct classes, by profile and by building material. The decision as to which type of dam to build depends largely on the foundation conditions in the valley and the construction materials available. Broadly, the choice of materials now lies between concrete, soils, and rock fill. Although in the past a number of dams were built of jointed masonry, this practice is now largely obsolete. The monolithic form of concrete dams permits greater variations in profile, according to the extent to which water pressure is resisted by the deadweight of the structure, is transferred laterally to buttresses, or is carried by horizontal arching across the valley to abutments formed by the sides of the valley.

 

Essential vocabulary:

1. dam - дамба

2. estuary – эстуарий, дельта, устье реки

3. to retain – сохранять, удерживать

4. to discharge – 1) выгружать, 2) разряжать, 3) выплачивать

5. demand - требование

6. consumption – потребление, поглощение

7. irrigation - орошение

8. floodwater – полая вода, половодье, наводнение

9. recreation - восстановление

10. auxiliary - вспомогательный

11. spillway - водослив

12. surplus - избыток

13. pipeline - трубопровод

14. silt – засор, ил

15. reap - пожинать

16. masonry – каменная кладка

17. to resist – сопротивляться, противостоять

18. obsolete - устаревший

19. deadweight – 1) грузоподъемность, 2) тяжелая конструкция

20. laterally - горизонтально

21. buttress - подпора

22. abutment - граница

 

 

I. Answer the following questions:

1. What is dam?

2. What are the usual works at a dam?

3. What role does a dam play in the conservation of water resources?

4. What classes do the dam fall into?

5. What is the usual choice of materials for dam constructing?

6. Why is the dam made of concrete considered to be better than others?

 

II. Make up a short dialogue using the following words and phrases:

- an incidental purpose

- auxiliary

- obsolete

- as far as I know / as far as….. is concerned….

- to depend largely on…

- available construction materials

- finally / broadly speaking

 

III. Give the definitions to the following words and phrases:

1. obsolete

2. multipurpose

3. auxiliary work

4. human consumption

5. to permit

6. to improve navigation