Match according to the text.

Answer the following questions.

1) What types of conduits are used to convey water?

2) What forms may the open channel take?

3) Open channels are characterized by a free water surface, aren’t they?

4) Why is the problem of canal location more difficult then the problem of highway location?

5) Why are canals lined?

6) What types of lining are used to reduce seepage losses from canals?

7) What appurtenances are necessary for the proper operation of canals?

8) What helps to regulate flow in the canal and to distribute water?

9) Where are flumes used to convey water?

10) Can wooden flumes be of rectangular, triangular and semicircular cross sections?

11) What types of wood is used in timber flumes?

12) Semicircular steel flumes are widely used, aren’t they?

13) Will the useful life of a well-maintained steel flume range from 15 to 50 years?

14) What is the disadvantage of concrete flumes?

15) Why are flumes and canals sometimes covered?

16) Is it always cheaper to convey water by tunnel than by flume or canal?

17) Are tunnels made use of horseshoe or circular section?

18) What may be used to prevent collapse of a tunnel if the tunnel material is unstable?

19) What tunnels need not be lined?

20) Do tunnels act as open channel when they are full of water?

Make a plan of the text and write a summary of the text.

Odd one out.

a) a channel, a canal, a flume, a check, a tunnel, a filled pipe

b) clay, asphalt, cement mortar, concrete, steel, gunite

c) pine, fir, redwood, cypress, paint

d) rectangular, circular, liner, triangular, semicircular, horseshoe

e) turnouts, wasteways, overchute, settling basins, depressions

f) a chute, an intake structure, a long section, an outlet

Make sure you know the verbs formed from the following nouns.

Match the words with their synonyms.

Fill in the correct prepositions then choose any three items and make sentences.

1) ___ some cases; 2) to take the form ___ a tunnel; 3) because ___ the velocity; 4) to be similar ___ sth.; 5) ___ either case; 6) to construct below ___ the point of water diversion; 7) to return back ___ the river; 8) as much ___ 90 per cent; 9) to be sluiced ___ the canal; 10) to convey water ___ the terrene; 11) to line ___ gunite.

Translate the following words into English using the vocabulary of the text.

Чрезмерный наклон, эрозия дна канала, приемные устройства канала, быстроток, обеспечить ровное течение, изменение уровня воды, вертикальный перепад, автомагистральная насыпь, водопропускная труба, ров, дюкер, шлюз-регулятор, водосбросный коллектор, лотковый акведук, срок службы, поверхность земли, понижение местности, оцинкованный металл, выпускное отверстие, лишняя кинетическая энергия, проводить воду, сбрасывать в реку, скопившиеся наносы, рыбозаградительные решетки, расположение канала, успешно использовать, вымывать из канала, дождевая вода, деревянный желоб.

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

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

What are the types of weirs?

Text B                   Measurement of Flow in Open Channels

The flow in large natural channels is usually measured with some types of meters. The flow in small streams and man-made channels may be more conveniently measured by other methods. Among the most common methods are the use of weirs and venturi-type flumes.

Weirs are the following: sharp-crested rectangular weirs, triangular or V-notch weirs and trapezoidal weirs. For weir to give accurate water discharge, the upstream face of the weir must be vertical and at right angles to the channel, and the crest of the weir must be horizontal. In addition atmospheric pressure should be maintained under the nappe, and the approach channel should be straight and without any obstruction. Corrosion of the weir crest or damage by floating debris may alter the weir coefficient.

When the water level downstream from a weir rises above the level of the weir crest, the weir crest is said to be submerged and under such conditions accurate flow measurement is not possible because surface disturbances of water downstream from the weir make it difficult to measure the depth of submergence.

The head on a weir is usually measured with a staff gage, though better results are obtainable with a hook or point gage in a stilling well. Inaccurate head determination will provide sizable error in measurements.

If water contains suspended particles, some of them will be deposited in the pool located above a weir, resulting in a gradual change in the weir coefficient. Moreover, the use of a weir results in a relatively large head loss. Both these difficulties are at least partially overcome by use of venturi-type flumes. For obtaining best results venture-flumes ought to be installed in a straight section of channel where flow conditions are relatively uniform. Usually venturi-flumes are made of galvanized iron, plain and reinforced concrete.

Finish the following sentences according to the text.

1) The flow in large natural channels is usually measured with …

2) Among the most common methods are the uses of …

3) The upstream face of the weir must be vertical and …

4) Atmospheric pressure should be maintained under …

5) The approach channel should be straight and without …

6) Corrosion of the weir crest or damage by floating debris may alter …

7) The head on a weir is usually measured with …

8) The deposition of suspended particles results in …

9) Venture-flumes ought to be installed in …

10) Venturi-flumes are made of …