CBSE X G III WATER RESOURCES

Class X

Geography

Unit III – Water Resources

Notes

Aquifer: An underground bed or layer of permeable rock, sediment or soil that yields water

Hydrological cycle or water cycle: It refers to the continuous circulation of water in the earth-atmosphere system through evaporation and condensation.

MNCs: Multi-National Companies or Corporations are enterprises that operate in several countries but are managed from one home country.

Conservation: Protecting from loss, damage, mismanagement or neglect.

Dam: A barrier across flowing water that obstructs, directs or retards the flow, creating a reservoir, lake or impoundment

Bhadu: A clan of Jats found in Rajastan, western Punjab and Madhya Pradesh.

River of sorrow: The Damodar River is known as the sorrow of West Bengal because it used to frequently flood several parts of Bengal like Bardhaman, Hugli, Howrah and Medinipur districts.

Spawning: Releasing eggs or sperm into water by aquatic animals

Guls / Kuls: Diversion channels built by people for agriculture in the western Himalayas

Khadins: Agricultural fields in Jaisalmer converted into rain fed storage structures that allow water to stand and moisten the soil

Johads: Agricultural fields in Rajastan converted into rain fed storage structures that allow water to stand and moisten the soil

Tankas: Large underground tanks for storing drinking water, as part of rooftop rainwater harvesting system, in Bikaner, Phalodi and Barmer (Rajastan)

Palar Pani: Rain water

Three-fourth of the earth’s surface is covered with water.

A very small proportion of the water available on the earth’s surface is fresh water.

96.5% of the total volume of world’s water exists as oceans. Only

2.5% is fresh water. Of this fresh water, 70%, that is, 1.75% of the total volume of world’s water occurs as ice-sheets and glaciers in Antarctica. The remaining 30% of the fresh water, that is, 0.75% of the total volume of world’s water is available as groundwater in the world’s aquifers.

Water is a renewable resource.

By the year 2025, nearly two billion people in the world will live in absolute water scarcity.

India receives about 4% of the global precipitation.

India ranks 133 in the world in terms of water availability per person per annum.

The total renewable water resources of India are estimated to be 1,897 km² / annum.

According to Falken Mark, water scarcity occurs when water availability is less than 1,000 cubic meters per person per year.

22% of the total electricity produced in India is hydroelectric or hydel power.

In the first century BC, Sringavera Pura near Allahabad had a sophisticated water harvesting system channelizing the flood water of the Ganga.

Bhopal lake, one of the largest artificial lakes of its time, was built in the 11^th century.

In the 14^th century, Iltutmish constructed a tank in Hauz Khas, Delhi, for supplying water to Siri fort area.

Bhakra Nangal Project is in the Satluj – Beas river basin.

Hirakud Project is in the Mahanadi river basin.

Jawahar Lal Nehru described dams as the temples of modern India.

Narmada Bachao Andolan is directed against the Sardar Sarovar Dam.

Sardar Sarovar dam is being built across the Narmada in Gujarat.

Increasing irrigation facilities made the farmers shift to water-intensive commercial farming.

Bamboo drip irrigation system is prevalent in Meghalaya.

The first and the only state in India to have introduced legal provisions for roof top rain water harvesting is Tamilnadu.

India will be one of the countries that will face acute water scarcity by the year 2025.

Falken Mark is a Swedish expert on the subject of water conservation.

Tube wells in agricultural farms can result in fall in groundwater levels affecting water availability and food scarcity.

The word ‘dam’ refers to the reservoir and not to the structure.

The practice of roof top rain water harvesting in Shillong, Meghalaya, is interesting because Shillong is just 55 km away from Cherapunjee and Mawsynram which receive the highest rainfall in the world.

In the tankas of Rajastan, the first spell of rain is not collected as it would clean the roofs and pipes.

Causes of water scarcity:

Over-exploitation

Excessive use

Unequal access to water among different social groups

Growing population

Agricultural expansion

Intensive industrialization and urbanization

Poor quality of water

Pollution

Sources of fresh water:

Precipitation

Surface runoff

Groundwater

Uses of dams:

Irrigation

Electricity generation

Water supply for domestic use

Water supply for industrial use

Flood control

Recreation

Inland navigation

Fish breeding

Disadvantages of dams:

They affect the natural flow of the river.

They cause excessive sedimentation at the bottom of the reservoir.

They worsen the conditions of life for aquatic fauna.

They make it difficult for aquatic fauna to migrate.

They submerge the existing vegetation.

They displace local communities.

Classification of dams on the basis of the materials used:

Timber dams

Embankment dams

Masonry dams

Classification of dams on the basis of height:

Major dams

Medium dams

Minor dams

Why dams are called the temples of modern India:

They integrate agricultural development and village economy with industrial development and urban economy.

Ecological consequences of commercial farming:

Increase in salinity level of soil

Increase in the social gap between the rich land owners and the landless poor.