GEOGRAPHY CLASS X CHAPTER 3 WATER RESOURCES

Water: Some facts and figures

• 96.5 per cent of the total volume of world’s water is estimated to exist as oceans and only 2.5 per cent as
freshwater. Nearly 70 per cent of this freshwater occurs as ice sheets and glaciers in Antarctica, Greenland and
the mountainous regions of the world, while a little less than 30 per cent is stored as groundwater in the
world’s aquifers.

• India receives nearly 4 per cent of the global precipitation and ranks 133 in the world in terms of water
availability per person per annum.

• The total renewable water resources of India are estimated at 1,897 sq km per annum.

• By 2025, it is predicted that large parts of India will join countries or regions having absolute water scarcity.

1. How is fresh water obtained?

Fresh water is mainly obtained from surface-runoff and ground water.

2. How the fresh water becomes a renewable resource?

Water is continually being renewed and recharged through the hydrological cycle .

3. Why does an area suffer from water scarcity although water is available in ample amount to meets the
needs of people?
Even if there is ample amount of water to meet the needs of the people much of it may be polluted by
domestic and industrial wastes chemicals , and, pesticides fertilizers used in agriculture, thus making it
hazardous for human use.

4. Why should we conserve water resource?

We need to conserve water resource
 To safeguard ourselves from health hazards
 To ensure food security
 To continue our livelihoods
 For productive activities
 To prevent degradation of our natural ecosystems

5. Explain the various causes of water scarcity?

a) Water scarcity may be the outcome of large and growing population and consequent greater demands
for water and unequal access to it.
b) A large population means more water not only for domestic use but also to produce more
food .Hence ,to facilitate higher food- grain production ,water resources are being over exploited to
expand irrigated areas and dry season agriculture.
c) Most farmers have their own wells and tube-wells in their farms for irrigation to increase their
produce. But it may lead to falling of ground water levels adversely affecting water availability and food
security of the people.
 d) Intensive industrialization is exerting pressure on existing fresh water resources.
e) Multiplying urban centers with large and dense populations and urban-life styles have not only added
to water and energy requirements but have further aggravated the problem.

6. Archaeological and historical records show that from ancient times we have been constructing
sophisticated hydraulic structures. Justify the statement with examples.

Hydraulic Structures in Ancient India

a) In the first century B.C., Sringaverapura near Allahabad had sophisticated water harvesting
system channelling the flood water of the river Ganga.
b) During the time of Chandragupta Maurya, dams, lakes and irrigation systems were extensively
built.
c) Evidences of sophisticated irrigation works have also been found in Kalinga, (Orissa),
Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra), etc.
d) In the 11th Century, Bhopal Lake, one of the largest artificial lakes of its time was built.
e) In the 14th Century, the tank in Hauz Khas, Delhi was constructed by Iltutmish for supplying
water to Siri Fort area.

7. What is a dam?
A dam is a barrier across flowing water that obstructs, directs or retards the flow ,often creating a
reservoir ,lake or impoundment. Dam refers to a reservoir rather than structure.

8. Classify the dams on the basis of material used and height.

Dams are classified according to material used and intended purpose or height—
(i) On the basis of structure and the material used dams are classified- (a)Timber dams
(b)Embankment dams
(c) Masonary dams
(ii) On the basis of height- (a)Low dams
(b) Medium dams
(c) High dams

9. Who proclaimed the dams as the ‘temples of modern India and why?

Jawahar Lal Nehru proudly proclaimed the dams as ‘temples of modern India’, the main reason being that it
would integrate development of agriculture and the village economy with rapid industrialization and growth
of the urban economy.

10. Differentiate between traditional dams and multi purpose river valley dams.
 Traditional dams were built to impound rivers and rainwater that could be used later to irrigate
agricultural fields.
 Today, dams are built not just for irrigation but for electricity generation, water supply for domestic
and industrial uses ,flood control ,recreation ,inland navigation ,and fish breeding. For example,
Bhakhra Nangal project water is used for hydel power production as well as for irrigation.
11. Discuss the problems associated with multipurpose river valley projects.
OR
In recent years, multi-purpose projects and large dams have come under great scrutiny and opposition
for a variety of reasons. Justify the statement by giving five value points.

The problems associated with multipurpose projects and large dams are following
a) AFFECT ON NATURAL FLOW OF RIVER- Regulating and damming of rivers affect their natural flow causing
poor sediment flow and excessive sedimentations at the bottom of the reservoir, resulting in rockier
stream beds and poorer habitats for the river’s acquatic life. Dams also fragment rivers making it difficult
for acquatic fauna to migrate, especially for spawning.
b) SUBMERGENCE OF VEGETATION- The reservoirs that are created on the flood plains also submerge the
existing vegetation and soil leading to its decomposition over a period of time.
c) SOCIAL PROBLEMS- Multipurpose projects and large dams have also been the cause of many new social
movements like the ‘Narmada Bachao Andolan ’and the’ Tehri Dam Andolan’ .
d) CHANGE IN CROPPING PATTERN- Irrigation has also changed the cropping pattern of many regions with
farmers shifting to water intensive and commercial crops. This has great ecological consequences like
salinisation of the soil
e) CONFLICTS AND DISPUTES- Inter-state water disputes are also becoming common with regard to sharing
the costs and benefits of the multipurpose projects e.g.objections raised by Karnataka and Andhra Pradesh
government regarding the Krishna –Godavari water.
f) TRIGGERS FLOODS- Ironically the dams that were constructed to control floods have rather triggered
floods,due to sedimentation in the reservoir
g) LAND DEGRADATION- Regulating and damming of rivers cause poor sediment flow and sedimentation at
the bottom of the reservoir, which means that the flood plains were deprived of silt ,a natural
fertilizer,further adding on to the problem of land degradation.
h) OTHER PROBLEMS- It was also observed that the multipurpose projects induced earthquakes, caused
water borne diseases and pests and pollution resulting from excessive use of water.

12. In ancient India, along with the sophisticated hydraulic structures, there existed an extraordinary
tradition of water-harvesting system. Justify the statement by giving examples of traditional rainwater
harvesting system.
a) People had in-depth knowledge of rainfall regimes and soil types and developed wide ranging techniques
to harvest rainwater, groundwater, river water and flood water in keeping with the local ecological
conditions and their water needs.
b) In hilly and mountainous regions, people built diversion channels for agriculture known as Guls or Kuls in
western Himalayas.
c) ‘Rooftop rain water harvesting’ was commonly practised to store drinking water, particularly in Rajasthan.
d) In the flood plains of Bengal, people developed inundation channels to irrigate their fields.
e) In arid and semi-arid regions, agricultural fields were converted into rain fed storage structures that
allowed the water to stand and moisten the soil like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts
of Rajasthan
13. What is ‘Palar Pani’?
Rainwater is commonly referred as ‘Palar Pani’ in Rajasthan. It is considered the purest form of natural
water.

14. Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to
conserve and store water?

In many parts of rural and urban India, rooftop rainwater harvesting is being successfully adapted to store and
conserve water
GENDATHUR

 In Gendathur, a remote backward village in Mysore, Karnataka, villagers have installed in their
household’s rooftop, rainwater harvesting system to meet their water needs.
 Nearly 200 households have installed this system and the village has earned the rare distinction of
being rich in rainwater.
 Gendathur receives an annual precipitation of 1,000mm and with 80% percent of collection efficiency
and of about 10 filling, every house can collect and use about 50,000 liters of water.
 From 20 houses, the net amount of rainwater harvested annually amounts to 1,00,0000 liters.

SHILLONG

 Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya.

 It is interesting because Cherapunji and Mawsynram situated at a distance of 55 km from Shillong
receives the highest rainfall in the world, the state capital Shillong faces acute shortage of water.
 Nearly every household in the city has a rooftop rainwater harvesting structure.
 Nearly 15-25% of the total water requirement of the household comes from rooftop water harvesting.

TAMILNADU

 It is the first and the only state in India which has made rooftop rainwater harvesting structure
compulsory to all the houses across the state.
 There are legal provisions to punish the defaulters.

15. Explain the ‘Bamboo Drip Irrigation System’

 In Meghalaya, a 200 years old system of tapping stream and spring water by using bamboo
pipes ,.About is prevalent 18-20 liters of water enters the bamboo pipe system, gets transported
over hundreds of meters, and finally reduces to 20- 80 drops per minute at the site of plant.
 Bamboo pipes are used to divert perennial springs on the hilltops to the lower reaches by gravity.
 The flow of water into the pipes is controlled by manipulating the pipe positions.
 Reduced channel sections and diversion units are used at the last stage of water applications. The
last channel section enables water to be dropped near the roots of the plant.

16. Why the practice of rooftop rainwater harvesting is declining in western part of Rajasthan?
The practice of rooftop rainwater harvesting is on the decline in western Rajasthan as plenty of water is
available due to the perennial Rajasthan canal.