GEOGRAPHY - CLASS - 8 - NATURAL RESOURCES – WATER

CLASS – 8
SOCIAL SCIENCE

GEOGRAPHY

INTRODUCTION:

• Water resources are natural resources of water
that are potentially useful. Uses of water include
agricultural, industrial, household, recreational
and environmental activities.

• All living things require water to grow and
reproduce.

• 97% of the water on the Earth is salt water and
only 3% is fresh water , slightly over two thirds
of this is frozen in glaciers and polar ice caps.

• The remaining unfrozen freshwater is found mainly as
groundwater, with only a small fraction present above
ground or in the air.

• Water, like land is a vital renewable resource.

• It supports and sustains all life forms on the earth.

In this lesson we are going to learn the following:

a. Need for water.

b. Types of water resources.

c. Multi-purpose river valley projects.

d. Need for conservation of water.

NEED FOR WATER :

• Plants and animals, living both on land and oceans, need
water.

• We need water for drinking, cleaning and other domestic
purposes.

• Water is essential for agriculture.
• It is used to generate hydro-electric power.
• Water is used for transportation, in industries, disposal of

sewage, and even for fire fighting.
• Ocean water is a store house of minerals such as salt and

magnesium. It consists of a number of organisms.

• The amount of water available on the Earth is more or less
fixed.

• Three key factors determine the demand for water :
a) Population.

b) Standard of living.

c) Economic development.

Due to the growing of population the demand for water
resource is under immense pressure.

TYPES OF WATER RESOURCES:

• 97% of the world’s water resource is not fit for human
consumption.

• Only 3% is freshwater resources is for human
consumption.

• Fresh water includes water in ice sheets, ice caps, glaciers
and even in underground water.

• It is the water in rivers, lakes, ponds, other surface bodies
and water under the ground (called ground water) that is
most precious to humans for survival.

RIVERS:
• A river is a natural flowing watercourse, usually freshwater,

flowing towards an ocean, sea, lake or another river.

• In some cases a river flows into the ground and becomes dry at the
end of its course without reaching another body of water.

• Small rivers can be referred to as stream, creek, brook, rivulet and rill.

• Rivers are part of the hydrological cycle.
• Water generally collects in a river from precipitation through a drainage

basin, from surface runoff and other sources such as groundwater
recharge, springs, and the release of stored water in natural ice and
snow packs (Eg: from glaciers).

• The area from where a river receives its water is known as the
Catchment Area of that river.

• The area that is drained by such a river is known as River
basin.

• POTAMOLOGY is the scientific study of rivers,
while LIMNOLOGY is the study of inland waters in general.

LAKES:
• A lake is an area filled with water, localized in a

basin, surrounded by land , apart from any river
or other outlet that serves to feed or drain the
lake.

• Lakes lie on land and are not part of the ocean.

• Therefore they are distinct from lagoons and
are also larger and deeper thanponds.

• Most lakes are fed and drained by rivers and
streams.

• All lakes are temporary over geologic time
scales , as they slowly fill in with sediments or
spill out of the basin containing them.

• Many lakes are artificial and are constructed for
industrial or agricultural use, for hydro- electric
power generation or domestic water supply, or
for aesthetic, recreational purposes, or other
activities.

GROUNDWATER

• Groundwater is the water present beneath Earth’s surface in
soil pore spaces and in the fractures of rock formations.

• A unit of rock or an unconsolidated deposit is called an aquifer
when it can yield a usable quantity of water.

• Ground water recharges from the surface, it may discharge
from the surface, it may discharge from the surface naturally
at springs and seeps, and can form oases or wetlands.

• A part of rainwater percolates into the ground through joints
and cracks in rocks.

• It is necessary to have soft, permeable rocks that allow to
percolate into the ground.

• This water gets stored in porous rocks underground
sometimes at great depths.

• Ground water can be accessed by digging wells and tube
wells and even through artesian wells.

What is an ARTESIAN WELL?

Water is trapped in saucer-shaped pervious rocks, sandwiched between two layers of impervious rocks. A section of the pervious
rock reaches the Earth’s surface. Rain falling on the ground seeps and fills the pervious rocks. A bore is made to take the water out.
This is an Artesian Well.

Some groundwater also feeds springs, brooks and rivers.

Australia, Greece, Alaska and most depositional plains in the world, like India and China, have good groundwater resources.

DISTRIBUTION OF FRESHWATER RESOURCES

• The distribution of water on the Earth’s surface is extremely uneven.
• Only 3% of water on the surface is fresh, the remaining 97% resides in the ocean.

• Of freshwater, 69% resides in glaciers, 30% underground and less than 1% is located in lakes, rivers and swamps.
• Naturally, the temperate lands or mid-latitudes where temperatures and evaporation are both low are regions of surplus water

resources.

• On the other hand, big tracts of desert lands between 20 degrees North and South are deficit water resources.

INDIA’S FRESHWATER RESOURCES

• Rivers constitute the most important source of surface water in India.

• It is estimated that India has river water resources of about 167 million
hectare meters.

• However due to topographical and other constraints , only 66 million
hectare meters or 32% of this water resource can be utilized for
irrigation.

• India has groundwater resources of about 40 million hectare meters.

• We use only 10 million hectare meters of this.

• The permeable sedimentary rocks of northern plains have vast
groundwater resources.

• But the Peninsula Plateau made up of old, hard, igneous, crystalline
rocks does not hold groundwater.

• Maharashtra, Madhya Pradesh, Tamil Nadu and the coastal plains have
some potential for groundwater resources.

• Fertile soils and level lands alone cannot be a boon to agriculture
without an adequate supply of water.

• The supply of water by rainfall is seasonal and unpredictable.

• With various means of storing and tapping water, the supply becomes
more regular and reliable.

MULTIPURPOSE RIVER VALLEY PROJECTS

MULTIPURPOSE RIVER VALLEY PROJECTS

Multipurpose river valley projects are basically designed for
the development of irrigation for agriculture and electricity

through the construction of dams.

Initially, dams were built only for storing rain water to
prevent flooding but now it became multipurpose.

DAMS:

• A dam is a barrier that stops or restricts the flow of water or
underground streams.

• Reservoirs created by dams not only suppress floods but also
provide water for activities such as irrigation, human consumption,
industrial use, aquaculture and navigability.

CANALS:
• Canals are waterways channels , or artificial waterways, for water

conveyance, or to service water transport vehicles.

• They may also help with irrigation.

• It can be thought of an artificial version of a river.
A canal is a manmade waterway that allows boats and ships to
pass from one body of water to another. They are used for transport.

Inundation canals are hollows dug out on both sides of a river to store
flood water during the rains.

Perennial canals carry water from artificial lakes or reservoirs ,
behind the dams , to areas where they are needed , all through the
year.

TANKS:
• A water tank is a container for storing water.

• Used to provide storage of water for use in many
applications, drinking water, irrigation agriculture,
fire suppression, agricultural farming, both for
plants and livestock, chemical manufacturing, food
preparation as well as many other uses.

WELLS AND TUBE WELLS:
• Well and tube well irrigation is the most popular

irrigation system in India.

• The utilization of groundwater through dug is an
indigenous form of irrigation.

• A dug well is a shallow well , with its bottom on a
fair depth below the water table, so that the water
from the surrounding aquifer accumulates in the
well.(aquifer – areas where groundwater is
collected).

• Water collected in the well is lifted to ground
surface through a water lift.

NEED FOR WATER CONSERVATION

Water conservation includes all the policies, strategies and
activities to sustainably manage the natural resource of fresh
water to protect the hydrosphere, and to meet the current and
future human demand.

Population, household size and growth influence the amount of
water which is used.

Factors such as climate change have increased pressures on
natural water resources especially in manufacturing and
agricultural irrigation.

MAJOR PROBLEMS AND CHALLENGES:
WATER SCARCITY:

Water scarcity is the lack of fresh water resources to meet
water demand.

It appears to be a major environmental concern as most
countries face a shortfall in some region.

The increasing world population, improving living standards,
changing consumption patterns , and expansion of irrigated
agriculture are the main driving forces for the rising global
demand for water.

Drought prone countries ,especially in Africa and Asia, are
the worst hit because they have the highest population too.



OVER – UTILISATION:

Overuse of groundwater for drinking , irrigation and domestic purposes has resulted in rapid depletion of
ground water in various regions leading to lowering of water table and drying of wells.
Pollution in groundwater aquifers has made many of these wells unfit for consumption.
Over exploitation of ground water lowers water tables, which may damage wetlands .
Rivers and streams have long been used for discharging the waters.
Most of the civilization have grown and furnished on the banks of rivers but unfortunately , growth in turn, has
been responsible for pollution of the rivers.

QUALITATIVE DECLINE:

Industrialization and water scarcity are the main causes of the qualitative decline in the purity of water.
The overuse and misuse of water is drastically affecting the amount of quality water resources we have.
The ineffectiveness of using resources is costing the general population a lot.
Industrialization is hugely responsible for excreting waste into water bodies and making it impossible to use
the water for any other purpose because of the amount of toxicity.

HOW TO CONSERVE WATER

Water conservation means using water wisely and not contributing
to unnecessary wastage.

Adequate amounts of excess rain and river water must be held in
storage to assure the continuing supply in dry weather. Dams help in
achieving this.
Must fight the pollution and depletion of existing water resources.

Governments must impose strict controls and norms on industrial units to
check harmful effluents. Likewise , sewage treatment is a must and there
should be strict laws to enforce it.

SEWAGE TREATMENT - It is the process of removing
contaminants from municipal wastewater, containing mainly
household sewage plus some industrial wastewater.

2 . Physical, chemical and biological processes are used to
remove contaminants and produce treated wastewater that is
safe enough for release into the environment.

3.Careful use of water in homes and industries to avoid
wastage. Recycling water for washing cars, watering plants
and domestic uses can reduce water shortage.
4.People must look into ocean water as an additional
resource. Desalination is an extremely expensive venture.
5.Irrigation facilities must be optimized to minimize water and
maximize productivity.
6.Groundwater aquifers must be allowed to recharge so that
water resources do not get exhausted.
7.Reforestation schemes go hand in hand with water
conservation. Trees allow for better recharge of groundwater.
8.Rainwater harvesting is another step for conservation.

WHAT IS RAINWATER HARVESTING?

Rainwater harvesting is the process of collecting
rainwater from surfaces on which rain falls, filtering it
and storing it for multiple uses.

Rainwater harvesting puts the supply of water back to
normal levels.

It is the collection and storage of water from surfaces
that rain has fallen upon.

CONCLUSION

• Water being an ongoing reliable source around the world, it will not be available
forever.

• Water scarcity is no joke and shouldn’t be taken lightly for it has great affects on
food production.

• Save water is an initiative to promote water conservation among people in order
to maintain the presence of clean water on the earth in future.

• Hence use water judiciously and save water for the future.

LET US HAVE A RECAP OF WHAT WE HAVE STUDIED
1.The area from which a river receives its supply of water is called Catchment area
2.A layer of pervious rock that holds water is known as Aquifer
3. Borewells are used to tap Groundwater
4.The most important sources of irrigation water in India are Wells
5. The ground water in an area depends on Permeable rocks
6. The area that is drained by a river River basin
7.Which is the most vital renewable resources needed for survival of Human

kind? Water