Q.1. How have the growing population, industrialisation and urbanisation led to water scarcity ? Explain. [CBSE 2008 (D)]
Explain any four reasons responsible for water scarcity in India. [CBSE 2010(D), Sept. 2012]
How have industrialisation and urbanisation aggravated water scarcity in India ? [CBSE Sept. 2010, 14]
Give three reasons for water scarcity in post independent India. [CBSE Sept. 2010]
‘Three-fourths of the earth’s surface is covered with water but there is still scarcity of water across the globe.’ Explain giving three reasons. [CBSE 2011]
Ans. (i) Growing population : Growing population is one of the basic factors which is responsible for the scarcity of water. Most of our cities are facing this problem due to overpopulation. A large population means more water not only for domestic use but also to produce more food.
(ii) Commercialisation of agriculture : After the success of Green Revolution, our farmers are producing commercial crops. The commercial crops need more water and other inputs. Assured means of irrigation like tube wells and wells are responsible for the falling groundwater levels.
(iii) Industrialisation : The post independent India witnessed intensive industrialisation and urbanisation. Today, large industrial houses are common in the form of industrial units of many MNCs (Multinational Corporations). The ever increasing number of industries has made matters worse by exerting pressure on the existing freshwater resources. Industries, apart from being heavy users of water, also require power to run them. Much of this energy comes from the hydroelectric power.
(iv) Urbanisation : Urbanisation has also aggravated the problem of water scarcity. Most of our cities are overpopulated. Overpopulation leads to over- utilisation of the water resources, and also pollutes the existing resources.
Q.2. How do the multipurpose river projects affect the aquatic life ? Explain.
Explain the ecological problems being faced due to the multi-purpose river projects. [CBSE 2013]
Ans. In recent years, the multi-purpose projects and large dams have come under great scrutiny and opposition for a variety of reasons :
(i) Regulating and damming of rivers affect their natural flow causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, resulting in rockier stream beds and poorer habitats for the rivers, as well as the aquatic life.
(ii) Dams also fragment rivers making it difficult for the aquatic fauna to migrate, especially for spawning.
(iii) The reservoirs that are created on the flood. Plains also submerge the existing vegetation and soil leading to its decomposition over time.
(iv) 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.
Q.3. Explain the quantitative and qualitative aspects of water scarcity.
Water is available in abundance in India even then scarcity of water is experienced in major parts of the country. Explain with four examples. [CBSE 2008 (D)]
Ans. (i) Quantitative aspect : This aspect is related to the availability of water resources. The availability of water resources varies over space and time mainly due to variations in seasonal and annual precipitation. However, water scarcity in most cases is caused by over-exploitation, excessive use and unequal access to water among different social groups.
(ii) Qualitative aspect : Now, let us consider another situation where water is sufficiently available to meet the needs of the people, but, the area still suffers from water scarcity. This scarcity may be due to bad quality of water. Lately, there has been a growing concern that even if there is ample water to meet the needs of the people, much of it may be polluted by domestic and industrial wastes, chemicals, pesticides and fertilizers used in agriculture, thus, making it hazardous for human use.
Q.4. Why is there an urgent need to conserve and manage our water resources ? Mention three reasons. [CBSE 2012]
Why is it necessary to conserve water resources in India ? Explain.
Why is it essential to conserve, and manage our water resources ? Explain any three reasons. [CBSE 2012]
Why we should conserve our water resources ? Explain any three reasons. [CBSE 2012,2014]
Ans. (i) Precondition for life : Water is necessary for life on earth. It is believed that life originated in water before it invaded land. Water is in fact a precondition of life.
(ii) Water essential for crops: Cultivation of crops depends on the availability of water. Water dissolves minerals and other nutrients in the ground. The roots of the plants draw this nutritious water for the soil. India is an agricultural country so availability of water is a must.
(iii) Water and industries : Industries need water as coolant, solvent, raw material, etc.
(iv) Water for daily life : Water is also used for drinking and domestic consumption. The growing urbanisation with its modern lifestyle has been demanding greater share of water day by day.
(v) Water an important component of ecosystem : Conservation of water is also important to prevent degradation of our natural ecosystems.
(vi) Water scarcity : It is essential to conserve and manage water because its overuse and misuse has lead to water scarcity.
Q.5. Examine the importance of the river valley projects in the development of hydel power and irrigational facilities in India.
Give any four objectives of the multipurpose river valley projects. [CBSE Sept. 2011]
Ans. (i) Generation of Power (electricity) :
These multipurpose projects are the main source of power generation. According to the Economic Survey, 2013, these produce more than 39,788.40 MW power. They provide us neat, pollution free and cheapest energy which is the backbone of industry and agriculture.
(ii) Flood Control : These projects control the floods because water can be stored in them. These projects have converted many ‘rivers of sorrows’ into ‘rivers of boon’. For example, the river Kosi.
(iii) Soil Conservation : They help to conserve the soil because they slow down the speed of water.
(iv) Irrigation : These projects are the main source of irrigation for our country. These irrigate the fields during the dry seasons. Many perennial canals have been dug and they irrigate dry areas.
Q.6. “In recent years, the multipurpose projects and large dams have come under great scrutiny.” Give reasons. [CBSE Sept. 2012]
Mention any four disadvantages of multi purpose projects. [CBSE Sept. 2010, 2013]
How may the multipurpose river valley projects become harmful for the country ? Explain with four examples. [CBSE 2008]
Why are multipurpose projects facing resistance ? Explain with three reasons. [CB$E Sept.2010]
Ans. (i) Adverse effect on the fertility of the soil : Due to the construction of dams, there are no annual floods in the river. And because of this, the soil of the downstream region does not get nutrient rich “silt”. This decreases the fertility of the soil.
(ii) Adverse impact on aquatic life: Due to the construction of dams on the rivers, the fish in the downstream area do not get sufficient nutrient material. Regulating and damming of rivers affect the natural flow of water causing poor sediment flow downward, and excessive sedimentation at the bottom of reservoir, resulting in rockier stream beds and poorer habitats for the rivers aquatic life. Dams also fragment rivers making it difficult for aquatic fauna to migrate for spawning i.e., to produce eggs.
(iii) Displacement of local communities : The building of large dams results in displacement of local communities. The local people often have to give up their land and livelihood and their meagre access and control over resources for the greater food of the nation.
(iv) Change in the cropping pattern : The multipurpose projects are responsible for providing assured means of irrigation to farmers. Due to this, most of the farmers have changed the cropping pattern shifting to water intensive and commercial crops. This has led to salinisation of soil leading to ecological imbalance.