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It's true! 96.5% of the Earth's water supply is salt water and only 2.8% is fresh water! That 2.8% is divided like this:

0.76% is groundwater (we can use some of this water) 0.0132% is in lakes and streams (we can use some of this water) 1.74% is in glaciers and icecaps 0.001% is water vapour Considering so little of the water on earth is drinkable to people, it is amazing the supply has survived as long as it has. The hydrologic cycle continues to move water and keep sources fresh. It is estimated that 100 million billion gallons a year are cycled through this process. Without this process life on Earth would be impossible. We need it to sustain us and for all of our life processes to function.

Without water life would not be possible on the Earth.

Diagram 1. Earth's Water Supply II. Match up the words or word-combinations with their definitions.

a) precipitation i. the volume of water that passes a given location within a given period of time, usually expressed in cubic feet per second b) aquifer ii. huge mass of ice, formed on land by the compaction and crystallization of snow, that moves very slowly down slope or outward due to its own weight c) runoff iii. water stored underground in rocks and in the pores of geologic materials that make up the Earth's crust d) infiltration iv. flow of water from the land surface into the subsurface e) transpiration v. rain, snow, hail, sleet, dew, and frost f) groundwater vi. that part of the precipitation, snow melt, or irrigation water that appears in uncontrolled surface streams, rivers, drains or sewers g) glacier vii. process by which water that is absorbed by plants, usually through the roots, is evaporated into the atmosphere from the plant surface, such as leaf pores h) reservoir viii. a geologic formation that is water bearing. A geological formation or structure that stores and/or transmits water, such as to wells and springs i) discharge ix. a pond, lake, or basin, either natural or artificial, for the storage, regulation, and control of water Time for Reading Read the text and put the paragraphs (1-8) in the correct order.

THE HYDROLOGIC CYCLE (1) Shallow groundwater is taken up by the roots of plants and is transpired from leaf surfaces back into the atmosphere. Transpiration is the movement of water through a plant to the atmosphere. Some water infiltrating into the ground goes deeper and replenishes aquifers, which store huge amounts of freshwater for long periods of time. Over time, this water keeps moving, some of it reenters the ocean, where the water cycle begins or ends.

(2) The hydrologic cycle is a model that describes the storage and movement of water between the biosphere, atmosphere, lithosphere, and the hydrosphere. Water on this planet can be stored in any one of the following reservoirs: atmosphere, oceans, lakes, rivers, soils, glaciers, snowfields, and groundwater. Water moves from one reservoir to another by way of processes like evaporation, condensation, precipitation, deposition, runoff, infiltration, transpiration, melting, and groundwater flow.

(3) Precipitation can be defined as any deposit in liquid or solid form that develops in a saturated atmospheric environment and generally falls from clouds. A number of different precipitation types are classified by meteorologists including rain, freezing rain, snow, ice pellets, snow pellets, and hail. In certain locations on the Earth, acid pollutants from the atmosphere are deposited in dry and wet forms on the Earths surface. Scientists generally call this process acid deposition.

(4) Rising air currents takes the vapor up into the atmosphere, where cooler temperatures cause the vapor to condense into clouds. Air currents move clouds around the globe, cloud particles collide, grow, and fall out of the sky as precipitation.

(5) Not all runoff flows into rivers. Much of it soaks into the ground as infiltration. Infiltration is the movement of water from precipitation into the soil layer. Some of this water stays close to the land surface and can seep back into surface water bodies and the ocean as groundwater discharge. Some groundwater finds openings in the land surface and emerges as freshwater springs.

(6) Some precipitation falls as snow and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Snowpacks in warmer climates often melt when spring arrives, and the melted water flows overland as snowmelt. Most precipitation falls back into the oceans or onto land, where, due to gravity, the precipitation flows over the ground as surface runoff.

(7) The water cycle has no starting point. But, let us begin with the oceans, since that is where most of Earth's water exists. The sun, which drives the water cycle, heats water in the oceans, which evaporates as vapor into the air. Evaporation is movement of free water to the atmosphere as a gas. It requires large amounts of energy. Water vapour in the atmosphere is commonly referred to as humidity.

(8) Runoff is the surface flow of water to areas of lower elevation. At the global scale, runoff flows from the landmasses to the oceans. The Earths continents experience runoff because of the imbalance between precipitation and evaporation. A portion of runoff enters rivers in valleys with streamflow towards the oceans. Runoff and groundwater seepage accumulate and are stored as freshwater in lakes.

Did You Get It I. Answer the following questions.

1. What is the hydrologic cycle 2. What are the reservoirs water can be stored in 3. Name the processes that move water from one reservoir to another.

4. Does the water cycle have a beginning 5. What drives the water cycle 6. What form does water evaporate into the air 7. How much energy does evaporation require 8. What causes the vapor to condense into clouds 9. What is the precipitation 10. Where can some precipitation as snow accumulate 11. What happens to most precipitation 12. What is runoff 13. What season does melted water flow as snowmelt 14. When can ground water emerge as freshwater springs 15. What is infiltration 16. What parts of plants take part in transpiration II. Say what statements are true and what ones are false. Comment on the true statements and correct the false ones. Use the following words to express your agreement or disagreement.

Agreement Disagreement I think so. I dont think so.

I believe so. I am afraid not.

I suppose so. I hardly think so.

Thats right. On the contrary.

I agree. I dont quite agree here.

That goes without saying.

Same here.

1. Atmosphere is a place where most of the Earth's water exists.

2. The force that drives the water cycle is the moon.

3. Water in ice caps and glaciers can be stored frozen for decades.

4. The cause of runoff on the continents is the imbalance between precipitation and condensation.

5. Runoff and ground-water seepage accumulate and are stored in freshwater lakes.

6. All runoff flows into rivers.

7. Deep ground water is taken up by the roots of plants and is transpired from leaf surfaces back into the atmosphere.

III. Complete the statements below according to the information in the text.

a) The hydrologic cycle is the storage and movement of water between _.

b) Water on the Earth is stored in the following reservoirs _.

c) The processes that move water from one reservoir to another are _.

d) Water vapour in the atmosphere is called _.

e) _ and _ are the two processes that move water from the Earths surface to its atmosphere.

f) Meteorologists classify precipitation as.

g) Globally runoff _.

h) Some ground water finds openings in the land surface and_.

i) Transpiration is the movement of water.

j) Aquifers store.

k) Acid deposition is a process when acid pollutants.

IV. Say what parts of water cycle the letters A-F on the arrows stand for.

A - B - C - D - E - F - Words, Words, Words I. Match up and explain the meaning.

1) land a) vapour 2) groundwater b) caps 3) freshwater c) surface 4) hydrologic d) currents 5) ice e) springs 6) surface f) seepage 7) air g) runoff 8) acid h) deposition 9) water i) cycle II. Find in the text words and word combinations expressing the following:

the top layer of earth, which plants can grow in;

the part of a plant that grows completely or partially under the ground;

the process when something changes from a solid to a liquid, usually because it has been heated;

a series of events or processes that is repeated again and again;

the amount of moisture in the air;

to crash violently;

a scientist studying the weather conditions;

frozen rain drops which fall as little hard balls of ice;

a substance that pollutes;

the natural force by which objects are attracted to each other;

height above sea-level;

the season between winter and summer;

a place where water comes up naturally from the ground;

to fill up again;

the direction of the current of water.

III. Read and translate the words with the same roots.

to deposit- deposits-deposition;

to store- stored-storage;

to move- moving- movement;

to melt- melted- snowmelt;

to seep- seepage;

to transpire-transpiration.

IV. Complete the following table.

Positive degree Comparative degree Superlative degree deeper warmest shallower low cooler large drier wettest saturated V. Using the words below fill the gaps in the text.

The hydrologic cycle takes place in the _(1) which contains all the water in the atmosphere, in and on the earth. The _(2)_ is the movement of water through this hydrosphere. The process begins with condensation. Condensation occurs when the temperature of the air or earth (3)_. So when the air cools enough, water vapour has to condense on particles in the air to form (4). As clouds form, winds move them across the globe, spreading out the _(5)_.

When the clouds can't hold the moisture, they (6)_ it in the form of precipitation, which can be snow, rain, hail, etc. The next three stages: infiltration, runoff, and evaporation occur (7)_. Infiltration occurs when precipitation _(8) into the ground. If precipitation occurs faster than it can infiltrate the ground, it becomes (9). Runoff remains on the surface and flows into streams, rivers, and eventually large bodies such as lakes or the ocean. Infiltrated groundwater moves (10) as it recharges rivers and heads towards large bodies of water. As both of these processes are happening, the power of the _(11) is driving this cycle by causing evaporation. Evaporation is the change of _(12) water to a vapour. Warm air (13)_ into the atmosphere and becomes the vapour involved in condensation.

liquid rises up hydrosphere sun changes cycle release clouds similarly simultaneously seeps runoff water vapour Time to Talk I. Note-taking and speaking.

a) Read the text The Hydrologic Cycle again and draw a diagram of the natural water cycle.

b) Using your notes tell about the hydrologic cycle.

II. Questions for further thought...

1. What would happen to the planet if the hydrologic cycle stopped functioning What would happen to societies as the supplies of water diminished Would our planet die 2. What would happen if the polar icecaps melted and the hydrologic cycle couldn't keep water levels stable Where would we go as water levels rose out of control 3. Could we ever use the ocean to supplement or water once freshwater disappears What ways could the oceans be used to provide us with a source of water UNIT V WATER POLLUTION Question Time Discuss the following question in groups.

What do you know about water pollution in your region Is it a serious problem What is the water quality in the reservoir Who is to blame as far as the situation with reservoir is concerned Time for Reading Which of the following words and word combinations would you expect to find in a text with the title Water pollution: natural and manmade. When you check your choices against the text, give paragraph references for any and make sure you understand the words.

quality health water supplies colour problems to cause people-made nature river wild animals reservoirs law toxic safe fish construction pesticides earthquake facilities sewage WATER POLLUTION: NATURAL AND MANMADE (A) "Clean water", "pure water", "clear water" are some of the terms we use in describing water of good quality. But what do they mean Pure water, two parts hydrogen and one part oxygen, is great in a laboratory but not for plants and animals.

Scientists have found out that water from most streams in their natural state contains the proportions of dissolved minerals necessary for human.

(B) Water is never entirely pure in nature. Water picks up a broad range of elements as it (i) moves through its cycle of evaporation, condensation, precipitation, and percolation on its (ii) way back to stream, lake, or sea. From the air, water picks up dissolved oxygen and other gases. As water passes through the rocks and soil, minerals are dissolved into it. Some materials are filtered out, but others (iii) remain in solution and are carried along with the water wherever it goes. Generally the deeper the water sinks into the ground, the more minerals and other materials it contains.

(C) Differences in mineral contents of water accounts for the way it (iv) looks, tastes, and smells. Sulphur compounds are a problem in the Bear Creek area of northern Alabama, giving water a bad odour at certain time of the year. At both Normandy, in middle Tennessee, and Bear Creek, the water naturally contains troublesome amounts of iron and manganese. This pollution, if not removed by the water treatment plant, causes colour problems in household water supplies. Natural occurrences, such as earthquakes, volcanic eruptions, and landslides, can cause severe pollution of lakes and streams. Large populations of wild animals can also contribute to high levels of bacteria in a stream, under certain conditions.

(D) The activity of people can be a source of pollution also. Just about everything people do causes some pollution. When fuels are burned, they (v) produce smoke and gases of various kinds. These gases and smoke eventually come back to earth and find their way into the water somewhere. There are also ashes or other residues from the burning process that become waste and can contaminate water supplies. Even the facilities designed to deal with wastes can become sources of pollution. Municipal wastewater treatment plants, industrial treatment facilities, septic tanks, landfills, and incinerators often are sources of water pollution.

Accidental spills of toxic or hazardous material are another source of sometimes severe water pollution. Other sources of people-made pollution include pesticides and fertilizers used in agriculture, surface mining, forestry practices, and construction activities. The operation of dams and reservoirs can also cause problems when the water released from dams is low in oxygen content. This (vi) causes problems for fish and other aquatic life downstream.

(E) Many millions of dollars have been spent on facilities that reduce the pollution caused by human activity. Plants have been built to make the water we drink safe, to cut down on wastewater pollution, and to clean up industrial wastes.

Laws and regulations have been established to force cities and industries to clean up their (vii) wastewater before it (viii) is returned to a stream or lake. Still more millions have been spent to clean up polluted waterways in the nation.

Did You Get It Text Organization I. Choose a headline for each paragraph.

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