WWW.DISSERS.RU

    !


Pages:     | 1 |   ...   | 3 | 4 || 6 |

In a text book;

in a scientific magazine;

in an encyclopedia.

GROUNDWATER (A) Groundwater is any water found below the land surface. It (i) is a longterm reservoir of the natural water cycle, as opposed to short-term water reservoirs like the atmosphere and fresh surface water. It (ii) is naturally replenished from above, as surface water from precipitation, streams, and rivers infiltrates into the ground. The study of the distribution and behavior of groundwater is hydrogeology.

(B) Groundwater is found in aquifers, in the pore spaces of rocks, in unconsolidated sediments, as permafrost, and as soil moisture. Groundwater flows to the surface naturally at springs and seeps and can form oases or swamps. It (iii) may also be tapped artificially by the digging of wells.

(C) Groundwater is often contained in aquifers, which (iv) are layers of permeable material that channel the groundwater's flow. Aquifers can be confined or unconfined. If a confined aquifer follows a downward grade from a recharge zone, groundwater can become pressurized as it (v) flows. This can create artesian wells that (vi) flow freely without the need of a pump. The top of the upper unconfined aquifer is called the water table, where water pressure is equal to atmospheric pressure. The region between the land surface and the water table is called the unsaturated zone. Within the this zone water is held to soil particles by adhesion and in pore spaces by capillary action.

(D) Groundwater is a highly useful and abundant resource, but it does not renew itself rapidly. If groundwater is extracted intensively from water wells, as for irrigation in arid regions, it may become depleted. The most evident problem that may result from this (vii) is a lowering of the water table beyond the reach of existing wells. Wells must consequently be deepened to reach the groundwater; in some places in India, the water table has dropped hundreds of feet due to overextraction.

(E) A lowered water table may, in turn, cause other problems such as subsidence. The film of groundwater around particles of an aquifer of unconsolidated sediment actually holds the particles apart, and the removal of this water will compact the sediment. Thus the aquifer is permanently reduced in capacity, and the surface of the ground may also subside. The city of New Orleans, Louisiana is actually below sea level today, and its (viii) subsidence is partly caused by removal of ground water under it (ix). In the coastal areas, a lowered water table may induce sea water to reverse the flow toward the sea. Sea water moving inland is called a saltwater intrusion. Alternatively, salt from mineral beds may leach into the groundwater.

(G) Not all groundwater problems are caused by overextraction. Pollutants dumped on the ground or in landfills may leach into the soil, and work their (x) way down into aquifers. Movement of water within the aquifer is then likely to spread the pollutant over a wide area, making the groundwater unusable. Areas of karst topography on limestone bedrock are especially vulnerable to surface pollution.

Did You Get It Text Organization.

I. Which paragraph contains information about a. saltwater intrusion b. problems caused by lowered water table c. types of aquifers d. problems caused by spreading of pollutants e. place where groundwater can be stored II. What do the following pronouns and adjectives stand for It (i) paragraph A that (vi) paragraph C It (ii) paragraph A this (vii) paragraph D It (iii) paragraph B its (viii) paragraph E which (iv) paragraph C it (ix) paragraph E it (v) paragraph C their (x) paragraph G III. Match the beginning of a sentence in column A with an ending in column B to produce a statement which is true according to the text.

A B (a) Groundwater (i) the distribution and behavior of groundwater.

(b) Aquifers, the pore spaces of (ii) has dropped hundreds of feet due to rocks, unconsolidated sediments overextraction.

(c) An aquifer (iii) flow freely without the need of a pump.

(d) In the water table (iv) is actually below sea level.

(e) Hydrogeology studies (v) are the places where groundwater is stored.

(f) The water table in India (vi) makes the groundwater unusable.

(g) Movement of polluted water (vii) is any water found below the land surface.

within the aquifer (h) New Orleans (viii) is a layer of permeable material that channel the groundwater's flow.

(i) Artesian wells (ix) water pressure is equal to atmospheric pressure.

IV. Say whether the following statements are true or false and give the paragraph number to show where your information came from.

Statement True/false # Paragraph i. The top of the upper unconfined aquifer is called the water table.

ii. Groundwater renews itself quickly.

iii. Subsidence of New Orleans is caused only by removal of ground water under it.

iv. Unnconsolidated sediments are known as permafrost and as soil moisture.

v. Groundwater may be tapped by the digging of wells.

vi. Grounwater is a short-term reservoir of the water cycle.

vii. Groundwater is a scarce resource.

viii. Groundwater can form springs, oases or swamps.

ix. They distinguish between two types of aquifers.

x. All groundwater problems are caused by overextraction.

xi. Within the unsaturated zone is held to soil particles by capillary action and in pore spaces by adhesion.

xii. In arid regions groundwater is used for irrigation intensively.



V. Using information from the text, complete the following table.

Groundwater problem Caused by 1. Lowering of the water table. 1.

2. 2.

etc. etc.

Words, Words, Words...

I. Match up and explain the meaning.

short-term table permeable moisture water sediments artesian pressure confined reservoir unsaturated well atmospheric beds mineral material unconsolidated aquifer soil zone II. Find in the text words and word combinations which mean the following.

Action in a particular way; to make a hole by taking away the earth; to direct;

the state or action of sticking together or to something; (of land) having so little rain as to be very dry and unproductive; to remove, to take out; to get rid of, to abandon; a type of rock containing calcium and other substances; the main stretch of solid rock in the ground supporting all the soil above it; a very small opening; an area of land which is always full of or covered with water; a land that is permanently frozen to a great depth, even though the surface may slightly thaw in the summer; a place where water can be taken from underground; not protected, weak; having the air pressure inside not much lower than the pressure on the Earth; absorbent (adj).

III. Complete the following table of corresponding nouns and verbs (most can be found in the text). Make sure you know the meaning.

Noun Verb removal to extract distribution behaviour to channel irrigation to create pressure movement adhesion to subside IV. Find words and expressions in the text with the opposite meaning to those listed below and give the paragraph.

Word or expression Words or expression # paragraph meaning the opposite a) bottom b) not very much c) artificially d) upward e) temporarily f) slowly g) rare, scarce h) rising V. Fill in the gaps with the words from the box. Note that one word is extra.

A spring is a water resource formed when the side of a hill, a valley bottom or other excavation intersects a flowing body of groundwater at or below the local water table, below which the subsurface material is (i)_with water. A spring is the result of an (ii) being filled to the point that the water overflows onto the land surface. _(iii)_ may be formed in any sort of rock, but are more prevalent in (iv)_ and dolomite. Water from springs usually is remarkably (v)_. Water from some springs, however, may be "tea-colored." This is caused by ground water coming in (vi) with naturally occurring minerals, like iron. Thermal springs are ordinary springs except that the water is (vii) and, in some places, hot, such as in the bubbling mud springs in Yellowstone National Park, Wyoming. Many thermal springs occur in regions of recent (viii) and are fed by water heated by contact with hot rocks far below the surface. Also, warm springs can even coexist with (ix)_, as in Greenland.

saturated icebergs contact clear limestone aquifer warm well volcanic activity springs Time to Talk Tell about groundwater, its usage and importance.

UNIT VIII WATER STORAGE IN ATMOSPHERE AND OCEANS Question Time Try to guess the meaning of the following words.

membrane reactor salt ocean process mechanical atmosphere direct distillation method chemicals potential condense presence equilibrium pressure mass ion transportation Time for Reading I. Read the text and match the headings with the paragraph number.

a) Precipitation water from the atmosphere.

b) Methods of artificial precipitation.

c) Method of producing fresh water.

II. Give as much information as you can about:

a) advantages of water contained in the oceans;

b) transportation and distribution of water to places where it is most needed;

c) the air upsets the equilibrium and causes precipitation;

d) applicable methods of bringing about artificial precipitation.

ATMOSPHERIC WATER AND OCEANS (i) Atmospheric water or water vapor has two major advantages over water contained in the oceans: it is to be found everywhere above the land surface and it is free of salt. For these reasons, it has been said that he who finds the key to precipitating water from the atmosphere solves part of one of the most difficult tasks in supplying water to needing areas, that of transportation and distribution.

Unfortunately, no large-scale, successful, economic method has yet been devised to tap this water supply and direct it to places where it is most needed. Or a serious initial obstacle lies in the fact that clouds are not necessarily water-bearing and may be dry. If they do contain water vapor, one of two things may happen to it. It may either dry out or condense and fall as rain or snow.

(ii) The most that we have been able to do is to cause a particular humid cloud - one that would almost certainly sooner or later have precipitated to shed its moisture at a time and place of our choosing. This achieved in one of two ways. The first involves the seeding of clouds from aeroplanes or rockets with small particles of various chemicals, which under auspicious circumstances cause water droplets to form and precipitation to take place. The second method is to create artificial convection currents by heating a large air mass near the ground. The air thereupon rises rapidly into the cloud, upsets the equilibrium, and causes precipitation. Some local successes have been achieved by these methods, but both are expensive and both depend upon the presence of water-filled clouds, something which can not, as yet, be ensured. Other, more widely applicable methods of brining about artificial precipitation may one day be devised, but that day is still distant.





(iii) The oceans remain by far the largest potential source of water and together with the inland seas contain 92, 7 per cent of the earths water. This water could be made potable if its saline content were reduced from about 35,000 parts per million to 500 parts per million or less. We have known for a long time that it is possible to produce freshwater by heating saltwater and so promoting distillation. It is only recently, however, that such processes have been developed on anything like a large scale. A number of processes are currently in use, of which the most promising are flash distillation and reverse osmosis. The former is based on the heating of brine and the reduction of pressure, which causes the liquid to flash into the steam. This process has been developed by British scientists, using gas-cooled nuclear reactors to supply the power, and it is generally agreed that for some time to come it will be the most economic source of desalted water. Reverse osmosis uses semi-permeable membranes which permit the passage of water but do not allow salt ions to pass through. Each of these processes depends upon the use of energy, which may be thermal, mechanical or solar.

Did You Get It I. Answer the questions.

1) What water has two main advantages 2) What water can be found above the land surface 3) What method has not devised yet 4) What does a serious initial obstacle lie in 5) What do the first and second methods involve 6) In what way does the air cause precipitation 7) Why are these methods very expensive 8) What is the largest potential source of water 9) How can water be made potable 10) How can we produce freshwater 11) What processes are currently in use 12) What processes are the most promising 13) How does reverse osmosis use semi-permeable membranes 14) What does each of these processes depend on II. Decide if these statements are true or false.

1) The first method involves planting of clouds from planes or rockets with small particles of various chemicals.

2) The second method is to create artificial convection currents by cooling a large air mass near the ground.

3) Clouds are necessarily water-bearing.

4) Atmospheric water is free of salt.

5) The inland seas remain the largest potential source of water.

6) It isnt possible to produce fresh water by heating salt water.

7) The most that we have been able to do is to cause a particular waterbearing cloud.

Words, Words, Words I. Find words in the text that have the following meanings.

1) think of 2) take up 3) damp 4) to be suitable 5) to be disturbed 6) show clearly 7) hotness 8) subject matter 9) stream of water 10) ability to do or act 11) very small bit 12) free from the moisture 13) let fall II. Match up the words with their definitions.

1) promote a) give or provide something needed or asked for;

2) distillation b) flowering plants elements of life from which another plant can grow;

3) vapor c) making liquid into gas and then making the gas into liquid;

4) seeding d) making or becoming smaller;

5) solve e) find the answer to the problem;

6) contain f) a gaslike form of a liquid, such as mist or steam, often caused by a sudden change of temperatures;

7) supply g) have or hold within itself;

8) reduction h) give higher position or rank.

III. Correct mistakes in the sentences.

1. This process which has no beginning and no end is been known as the hydrologic cycle.

2. This cyclical movement of water is divisible into the three main stages.

3. Each of these process suffer from the disadvantages that the cost of desalination is very high.

4. It is desalinated water used almost exclusively for drinking.

5. Some countries signed the agreement to undertake joint research into the possibilities of using the atomic energy to desalinate salt water.

6. This total global evaporation is exactly balance by the total precipitation.

IV. Find in the text the derivations of the following words. Make as many words as possible of the same roots.

atmosphere presence to achieve salt pressure to reduce success ocean to develop economy mechanics to cool rain to precipitate V. Complete the sentences with the correct form of the words in brackets.

1. This process which has no beginning and no end is known as the _ cycle. (hydrology) 2. It _ a gigantic system operating in and on the land and oceans of the earth. (comprise) 3. This cyclical movement of water is into three main stages.

(divide) 4. It will be seen, therefore, that the hydrological cycle is completed in these ways; water which _ in the oceans, sooner or later _ to them. (begin, return) 5. In the second stage of the cycle the air masses _ the water vapor are suddenly cooled. (contain).

6. It _ that something like 80,000 cubic miles of water are evaporated each year from the oceans. (estimate).

7. These areas have a marked seasonal of rain. (short) 8. This total global evaporation is balanced by the total precipitation. (exact) VI. Use the words from the box to fill in the gaps.

Pages:     | 1 |   ...   | 3 | 4 || 6 |










2011 www.dissers.ru -

, .
, , , , 1-2 .