Some Facts and Figures of Water:

  • TWO-THIRD OF THE EARTH'S SURFACE IS COVERED WITH WATER.
  • Earth is also known as "Watery Planet", because 71% of the earth's surface is covered with water and only 29% is land.
  • World Water Day is celebrated on 22 March.

 

Distribution of Water:

1. 97% of the total volume of water is covered by Seas and Oceans

2. 3% as fresh water available on earth.

    (a) Out of 2% of the fresh water available, nearly 70% is in the form of "ICE" and is found in glaciers in Antarctica, Greenland, mountain regions, etc.

    (b) Only 1% of water is fit to use. It is found as underground water, surface water in rivers and lakes and also, water vapors' in the Atmosphere.

 

Water is available in three forms:

1. Water vapor's

2. Water in ocean, lakes & rivers

3. Ice in the glaciers & ice caps

 

HYDROLOGICAL CYCLE

  • The fresh water is continuously being renewed and recharged through hydrological cycle.
  • The sun's heat causes evaporation of water vapour.
  • When the water vapour cools down, it condenses and forms clouds.
  • From there it may fall on the land or sea in the form of rain, snow or sleet which is known as precipitation.
  • The process by which water continually changes its form and circulates between oceans, atmosphere and land is known as the Water Cycle or the Hydrological Cycle.

 

Usage of Water:

1. Drinking                                         2. Bathing                                           3. Washing

4.  Cooking                                        5. Irrigation                                         6. Construction, etc.

7. Water used in Industries                  8. Generating Electricity

 

PROBLEM OF WATER AVAILABILITY

  • Water is available in abundance and is renewable. Then why we suffer from water scarcity?
  • Water is not evenly divided around the world. Some places have lots and others have very little. Water supply is a big problem in some countries like, Africa, West Asia, South Asia, etc.

According to Mr. Falkenmark (a Swedish Expert), Water Stress Indicator, a country or region is said to experience "water stress" when annual water supplies drop below 1,700 cubic metres per person per year. At levels between 1,700 and 1,000 cubic metres per person per year, periodic or limited water shortages can be expected. When water supplies drop below 1,000 cubic metres per person per year, the country faces "water scarcity".

 

CONSERVATION OF WATER

Some of the important ways to conserve water are: -

1.  Decrease of water pollution:- Discharge of untreated sewage, agriculture chemicals & industrial effluents.

2.  Proper irrigation method.

     (a) Sprinklers can be used to irrigate very large area.

     (b) Drip irrigation can be used in dry regions, where evaporation is very high.

3.  Water Harvesting Method: This water can be used for cleaning, washing, gardening, etc.

4.  Water conservation in the home.

  • Check faucets and pipes for leaks.
  • Check your toilets for leaks.
  • Use your water meter to check for hidden water leaks.
  • Install water-saving shower heads and low-flow faucet aerators.
  • Put plastic bottles or float booster in your toilet tank.
  • Insulate your water pipes.
  • Take shorter showers.
  • Turn off the water after you wet your toothbrush.
  • Use your dishwasher and clothes washer for only full loads.
  • When washing dishes by hand, don't leave the water running for rinsing.

 

MOVEMENT OF OCEAN WATER OR OCEAN CIRCULATION

  • March 22 is celebrated as World Water Day.
  • Ocean water keeps moving continuously. It is never still.
  • The movements that occur in oceans can be broadly categorized as:Waves, Tides and Currents.

 

WAVES

  • When the water on the surface of the ocean rises and falls alternately, they are called waves.
  • During a storm, the winds blowing at very high speed form huge waves.
  • These may cause tremendous destruction.An earthquake, a volcanic eruption or underwater landslides can shift large amounts of ocean water. As a result a huge tidal wave called tsunami.
  • Tsunami is a Japanese word that means "Harbour waves" as the harbours get destroyed whenever there is tsunami. The term "Tsunami" has been derived from: - "Tsu" – Harbour and "Nami" – Waves. Meaning huge tidal waves.

 

TIDES

  • The rhythmic rise and fall of ocean water twice in a day is called a tide.
  • It is high tide when water covers much of the shore by rising to its highest level.
  • It is low tide when water falls to its lowest level and recedes from the shore.
  • During the full moon and new moon days, the sun, the moon and the earth are in the same line and the tides are highest. These tides are called spring tides.
  • But when the moon is in its first and last quarter, the ocean waters get drawn in diagonally opposite directions by the gravitational pull of sun and earth resulting in low tides. These tides are called neap tides.
  • High tides help in navigation.
  • This helps the ships to arrive at the harbour more easily.
  • The high tides also help in fishing.
  • Also, the rise and fall of water due to tides is being used to generate electricity in some places.

 

OCEAN CURRENTS

The horizontal movement of ocean water in the form of streams flowing constantly in definite directions is known as Ocean Currents.

 

Factors affecting the Ocean Currents: -

1.  Planetary Winds

2.  Rotation of the Earth

3.   Variation in the temperature

4.  Density of ocean water

5.  Shapes of  the coastlines

 

  • The ocean currents may be warm or cold.
  • The warm ocean currents originate near the equator and move towards the poles.
  • The cold currents carry water from polar or higher latitudes to tropical or lower latitudes.
  • The ocean current influence the temperature conditions of the area.
  • The place where warm and cold currents meet, dens fog is produced, reducing the visibility and thus, making it difficult for navigation. But at the same time these are the best fishing grounds of the world.
  • The general circulation of ocean currents is clockwise in the Northern Hemisphere and anti-clockwise in the Southern Hemisphere.

 

 

CASE STUDY

(TSUNAMI IN THE INDIAN OCEAN ON 26 DECEMBER 2004)

  • Tsunami or the harbour wave struck havoc in the Indian Ocean on the 26 December 2004.
  • The wave was the result of the earthquake that had its epicenter close to the western boundary of Sumatra in Indonesia.
  • The magnitude of the earthquake was 9.0 on the Richter scale.
  • Tsunami affected the coastlines of South and Southeast Asian countries. India, Indonesia, Sri Lanka, Thailand, etc were some of the countries where destruction was maximum.
  • Tsunami travelled at a speed of about 800km. per hour and completely washed away some of the islands in the Indian ocean.
  • The Indira point in the Andaman and Nicobar islands that marked the southernmost point of India got completely submerged. In India, the worst affected were the coastal areas of Andhra Pradesh, Tamil Nadu, Kerala, Puducherry and the Andaman and Nicobar Islands.
  • The earthquake-induced tsunami resulted in at least 1.8 lakh dead, 500,000 injuries, and damages that exceeded $10 billion. Also, it is estimated that 5 million people lost their homes or access to food and water.
  • Relief work was carried out at a great speed. All types of helps were received from all the corners of the world. Serious efforts were made by the government and non-government agencies to bring back life of the leftovers on track.

 

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