NCERT Book Class 12 Geography Water Resources

WATER RESOURCES

Do you think that what exists today will continue to be so, or the future is going to be  different in some respects? It can be said with some certainty that the societies will witness demographic transition, geographical shift of population, technological advancement, degradation of environment and water scarcity. Water scarcity is possibly to pose the greatest challenge on account of its increased demand coupled with shrinking supplies due to over utilisation and pollution. Water is a cyclic resource with abundant supplies on the globe.

Approximately, 71 per cent of the earth’s surface is covered with it but fresh water constitutes only about 3 per cent of the total water. In fact, a very small proportion of fresh water is effectively available for human use. The availability of fresh water varies over space and time. The tensions and disputes on sharing and control of this scare resource are becoming contested issues among communities, regions, and states. The assessment, efficient use and conservation of water, therefore, become necessary to ensure development. In this chapter, we shall discuss water resources in India, its geographical distribution, sectoral utilisation, and methods of its conservation and management.

Water Resources of India

India accounts for about 2.45 per cent of world’s surface area, 4 per cent of the world’s water resources and about 16 per cent of world’s population. The total water available from precipitation in the country in a year is about4,000 cubic km. The availability from surface water and replenishable groundwater is 1,869 cubic km. Out of this only 60 per cent can be put to beneficial uses. Thus, the total utilisable water resource in the country is only 1,122 cubic km.

Surface Water Resources

There are four major sources of surface water. These are rivers, lakes, ponds, and tanks. In the country, there are about 10,360 rivers and their tributaries longer than 1.6 km each. The mean annual flow in all the river basins in India is estimated to be 1,869 cubic km.

Groundwater Resources

The total replenishable groundwater resources in the country are about 432 cubic km. Table 6.1 shows that the Ganga and the Brahamaputra basins, have about 46 per cent of the total replenishable groundwater resources. The level of groundwater utilisation is relatively high in the river basins lying in north-western region and parts of south India.

EXERCISES

1. Choose the right answers of the following from the given options.

    (i) Which one of the following types describes water as a resource?

         (a) Abiotic resource                                (c) Biotic Resource

         (b) Non-renewable Resources                  (d) Cyclic Resource

    (ii) Which one of the following rivers has the highest replenishable ground water resource in the country?

         (a) The Indus                                        (c) The Ganga

         (b) The Brahmaputra                              (d) The Godavari

    (iii) Which of the following figures in cubic kilometres correctly shows the total annual precipitation in India?

         (a) 2,000                                              (c) 4,000

         (b) 3,000                                              (d) 5,000

    (iv) Which one of the following south Indian states has the highest groundwater utilisation (in per cent) of its total ground water potential?

         (a) Tamil Nadu                                      (c) Andhra Pradesh

         (b) Karnataka                                        (d) Kerala

    (v) The highest proportion of the total water used in the country is in which one of the following sectors?

         (a) Irrigation                                          (c) Domestic use

         (b) Industries                                        (d) None of the above

2. Answer the following questions in about 30 words.

    (i) It is said that the water resources in India have been depleting very fast. Discuss the factors responsible for depletion of water resources?

    (ii) What factors are responsible for the highest groundwater development in the states of Punjab, Haryana, and Tamil Nadu?

    (iii) Why the share of agricultural sector in total water used in the country is expected to decline?

    (iv) What can be possible impacts of consumption of contaminated/unclean water on the people?

3. Answer the following questions in about 150 words.

    (i) Discuss the availability of water resources in the country and factors that determine its spatial distribution?

    (ii) The depleting water resources may lead to social conflicts and disputes. Elaborate it with suitable examples?

    (iii) What is watershed management? Do you think it can play an important role in sustainable development?

Please refer to attached file for NCERT Class 12 Geography Water Resources