17. Study the diagram below and fulfill the following tasks using the information of Text b.

a) Fill in the correct numbers in the following text from the list below.

On the average, … gallons (… liters) of precipitation fall on the United States every day. About … per cent of this moisture returns directly to the air by evaporation, or is used by plants where it falls. People use about … per cent of the precipitation.

a - 6; b - 15,900,000,000,000;

c - 70; d - 4,200,000,000,000

b) Answer the following questions:

1. How much precipitation is returned unused to the sea?

2. How much precipitation do people use?

3. What is 6% of precipitation used for?

4. What is city use of water if industrial use is 3.12 per cent and irrigation use is 2.46 per cent?

c) Give the examples of …

• industrial use of water

• irrigation use

• city use

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

to affect	to utilize	improvement
shortage	utilization	to increase
available	reclamation system	to involve
supply (v)	irrigation system	natural resource
supply (n)	to require	destruction
sewerage	to prevent	application
exploitation	to expand	land drainage
existence	to neglect	impurity
culvert	to ensure	facilities
to construct	to subdivide	branch
construction	to relate to	urban
facilities	to deal with	liquid
management	to exploit	development
water at rest and in motion

19. Skim the text. Answer the following question.

What is water-resources engineering?

Text C Water-Resources Engineering

Man has affected his environment ever since he introduced agriculture and started to exploit natural resources. And the very existence of humans, animals, and plants has always depended on the availability of water. Without it, there would be no life on the earth.

But the supply of water available for our use is limited by nature. Although there is plenty of water on the earth, it is not always in the right place and at the right time. Moreover, chemical wastes discarded yesterday are showing up in our water supplies today.

So the development of water resources is known to require the planning, design, construction and operation of facilities to control and utilize water. It is basically a function of civil engineers, but the help of such specialists as geologists, chemists, biologists, economists is also required. In other words water-resources engineering is a science of designing, construction and utilizing hydraulic structures (such as dams and hydropower stations), and structures related to the river and sea transport, reclamation and irrigation systems.

Thus, hydraulic engineering may be subdivided into four main branches:

1. Water projects;

2. Hydropower stations;

3. River and sea transport;

4. Reclamation and irrigation systems.

Water-resources engineering involves the application of engineering principles and methods for control, conservation and utilization of water.

Flood control, land drainage, sewerage and highway culvert design are fields where water-resources engineering is used for the control of water in natural processes and in human society.

Water supply, irrigation, hydroelectric power development and navigation improvement are examples of the utilization of water.

Conservation is planned management of a natural resource or of a particular ecosystem to prevent exploitation, pollution, destruction, or neglect and to ensure the future usability of the resource.

Modern civilization is far more dependent on water than the civilizations of the past. The increasing population requires expanded areas for agriculture, much of which must come through land drainage and irrigation. Increasing urban population requires more attention to water supply and sewerage. Industrial progress also requires much water. Thus, all factors point to unprecedented development of water-resources engineering in the future.

Do you know that the term “hydraulics” is derived from a Greek word meaning water and is fundamentally the science dealing with water at rest and in motion?