Finish the following sentences according to the text.

1) In the design of almost every dam there must be .....

2) ..... permit to control the release of water.

3) Spillways must have the capacity to discharge major floods without...

4) Overflow spillways are widely used on ....

5) A steep-sloped open channel is called a chute, or ... and which is usually constructed of ...

6) It may be constructed around .... when ...

7) ... is one in which the flow after passing over the crest is carried away in a channel running ...

8) In a shaft spillway the water drops through ...

9) Small shaft spillways may be constructed of ...

10) ... may be used if space is limited.

Answer the following questions.

1) Is spillway the dangerous valve for a dam?

2) What is an overflow spillway designed to?

3) What structure is relatively light and is well adapted to earth and rock-fill dams?

4) Why is the chute usually narrowed and then widened near the end?

5) What drains may be used?

6) Where is a side-channel spillway used?

7) Where can a shaft spillway be used?

8) What advantages have siphon spillways?

Copy out the table and fill in it.

Make a short summary of the text.

Choose the pairs of opposites.

necessary, to build, to permit, maximum, open, light, possible, to narrow, watertight, high, vertical, limited, impossible, to widen, permeable, low, horizontal, unlimited, heavy, close, to forbid, minimum, to damage, unnecessary, dangerous, safe

Choose the pairs of synonyms.

dam, velocity, sufficient, a trough, space, discharge, harm, room, a chute, to allow, structure, release, adequate, speed, embankment, construction, damage, to permit

Fill in the necessary preposition.

1) ___ the design ___ every dam; 2) to prevent sth ___ sth; 3) to be a safety valve ___ sth; 4) ___ the same time; 5) to flow ___ sth; 6) to be constructed __ sth; 7) to be preferred ___ sth; 8) to be required ___ sth; 9) to be available ___ sth; 10) to drop ___ sth.

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

Сливать воду, предотвращать от разрушения, различные цели, объем воды, дополнительные сооружения, в тоже время, заранее установленный уровень воды, крутой откос открытого канала, железобетонные плиты, топографические условия, предпочтительное местоположение, постоянная ширина, уменьшать скорость, параллельно гребню, вертикальный трубопровод, автоматически поддерживать уровень воды, проходить через гребень, построенный полностью из металла.

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 main types of gates?

Text B                                           Gates and Outlet Works

Additional storage of water above the spillway crest can be obtained by the installation of temporary or movable gates. There are several types of gates.

The usual flashboard gates consist of wooden panels, supported by vertical pins placed on the crest of the spillway. Such installations are temporary. They are removed when the water surface reaches in the reservoir a predetermined level.

Stop logs consist of horizontal timbers spanning the space between piers. The logs may be raised by hand or with a hoist. There is usually much leakage between the logs and considerable time may be required for removing the logs if they become jammed in the slots. Stop logs are ordinarily used for small installations.

Needles consist of timbers with their lower ends resting in a keyway on the spillway crest and their upper ends supported by a bridge. Needles are somewhat easier to remove than stop logs but are quite difficult to place in flowing water. Consequently they are used mainly for emergency bulkheads where they need not be replaced until flow has stopped. There are some other types of gates, such as vertical lift gates, radial gates, rolling gates, bear-trap gates, drum gates.

Outlet works must be provided in order that water can be drawn from the reservoir when it is required. This water may be discharged into the channel below the dam or may be transported in pipes or canals to some distant point. All outlet works must be provided with gates or valves in order to regulate discharges of water.

A sluiceway is a pipe or tunnel that passes directly through a dam or the hillside at one end of the dam and discharges into the stream below. The outlets of most dams consist of one or more sluiceways, with their inlet being at about minimum reservoir level. If the quantity of discharged water is to vary considerably, then several sluiceways are required.

Sluiceways may be circular or rectangular. The interior should be smooth and without projections or cavities. Considerable attention should be given to the design of the sluiceway entrance. A bell mouth entrance is generally used.

Answer the following questions.

1) What are gates used for?

2) What types of gates are there?

3) What do the flashboard gates consist of?

4) When are the flashboard gates removed?

5) What do stop logs consist of?

6) What are stop logs used for?

7) What do needles consist of?

8) Are needles quite difficult to place in flowing water?

9) Where are needles used for?

10) Why must outlet works be provided?

11) Why must all outlet works be provided with gates or valves?

12) What is a sluiceway?

13) What do the outlets of most dams consist of?

14) When are several sluiceways required?

15) May sluiceways be polygonal in shape?

16) What should the interior of sluiceways be?

17) What is also important for sluiceways?