NCERT Solutions for Class 12 Geography Ch 6 Water Resources

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

(b) Non-renewable Resources

(d) Cyclic Resource

► (d) Cyclic Resource

(ii) 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

(b) Karnataka

(d) Kerala

► (a) Tamil Nadu

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

(a) Irrigation

(b) Industries

(d) None of the above

► (a) Irrigation

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?

Answer

It is true that water resources in India have been depleting very fast. The factors responsible are:

• The per capita availability of water is dwindling day by day due to increase in population.

• The available water resources are also getting polluted with industrial, agricultural and domestic effluents which in turn limiting the availability of usable water resources.

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

Answer

Groundwater development in the states of Punjab, Haryana, and Tamil Nadu has been intense due to irrigated agriculture because:

• The development of irrigation to increase agricultural production and these were the target regions for green revolution.

• Spatio-temporal variability in rainfall makes irrigation a necessary alternative for agriculture in the country.

• Provision of irrigation makes multiple cropping possible.

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

Answer

In future, the use of water is increasing in Industrial and Household sectors. Its result will be that the share of agricultural sector in total water used will decline.

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

Answer

Due to use of contaminated water, some diseases are caused like Cholera, Typhoid, Dysentery etc. which are life threatening.

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?

Answer

India accounts for about 2.45 per cent of the world’s surface area, 4 per cent of the world’s water resources and about 16 per cent of the world’s population. The total water available from precipitation in the country in a year is about 4,000 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.

Factors that determine its spatial distribution:

• Water flow in a river depends on size of its catchment area or river basin and rainfall within its catchment area.

• Precipitation is mainly concentrated in Monsoon season.

• The precipitation is relatively high in the catchment areas of the Ganga, the Brahmaputra and the Barak rivers, these rivers, although account for only about one-third of the total area in the country, have 60 per cent of the total surface water resources.

• The annual water flow in south Indian rivers like the Godavari, the Krishna, and the Kaveri has been harnessed, but it is yet to be done in the Brahmaputra and the Ganga basins.

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

Answer

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 freshwater constitutes only about 3 per cent of the total water. In fact, a very small proportion of freshwater is effectively available for human use.

The availability of freshwater varies over space and time. The tensions and disputes on sharing and control of this scarce resource are becoming contested issues among communities, regions, and states.

• The sharing of waters of rivers of Punjab, Haryana, Himachal Pradesh is a contesting issue.

• Since long, the dispute is going on between Tamil Nadu and Karnataka over the waters of Kaveri River.

• The sharing of waters of Narmada Basin is a dispute between the states of Maharashtra, Madhya Pradesh and Gujarat.

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

Answer

Watershed management basically refers to efficient management and conservation of surface and groundwater resources with community participation. It involves prevention of runoff and storage and recharge of groundwater through various methods like percolation tanks, recharge wells, etc. Watershed management aims at bringing about balance between natural resources on the one hand and society on the other. The success of watershed development largely depends upon community participation. The Project is being executed by Gram Panchayats with people’s participation:

• Haryali is a watershed development project sponsored by the Central Government which aims at enabling the rural population to conserve water for drinking, irrigation, fisheries and afforestation. The Central and State Governments have initiated many watershed development and management programmes in the country:

• Neeru-Meeru (Water and You) programme (in Andhra Pradesh) and Arvary Pani Sansad (in Alwar, Rajasthan) have taken up constructions of various water-harvesting structures such as percolation tanks, dug out ponds (Johad), check dams, etc., through people’s participation.

Short Answer Type Questions

Question 1.

What are the three things essential for water resource development?

Answer:

A very small proportion of fresh water is 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 have become serious problems. So assessment, efficient use and Conservation of water, have become necessary to ensure development.

Question 2.

Why does the use of groundwater vary from state to state?

Answer:

The rate of groundwater utilization is very high in the river basins of north west India and parts of south India, where the rain water percolates down easily through the soft soils and recharge underground water table. It is also easy to construct wells and tube wells here. Surface water is more utilized in the crystalline rocks of south India.

Question 3.

What are the emerging water problems facing India?

Answer:

The over-use of groundwater resources has led to decline in ground water table in the states of Punjab, Haryana, western Uttar Pradesh. In fact, over withdrawals in some states like Rajasthan and Maharashtra has increased fluoride concentration in groundwater, and this practice has led to increase in concentration of arsenic in parts of West Bengal and Bihar. The per capita availability of water is dwindling day by day due to increase in population. The available water resources are also getting polluted with industrial, agricultural and domestic effluents,

and this, in turn, is further limiting the availability of usable water resources.

Question 4.

When was National Water Policy undertaken? Give its key features.

Answer:

The National Water Policy was undertaken in 2002, to prioritized the ‘ water allocation in the different sectors in the following order:

Drinking water, Irrigation, Hydro power, Navigation, Industrial and Other uses. Highlights:

Providing drinking water is the first priority.
Irrigation and multi-purpose projects should include drinking water in areas where it is not available.
Regulate and limit groundwater exploitation.
Regular monitoring of water sources for quality.
Awareness and conservation consciousness should be promoted.

Question 5.

What do you mean by degradation of water resources?

Answer:

Water quality refers to the purity of water, or water without unwanted foreign substances. Water gets polluted by foreign matters such as micro-organisms, chemicals, industrial and other wastes. Such matters deteriorate the quality of water and render it unfit for human use. When toxic substances enter lakes, steams, rivers, ocean and other water bodies, they get dissolved or lie suspended in water. This results in pollution of water whereby the quality of water deteriorates affecting aquatic systems.

Question 6.

Why is the level of groundwater utilization relatively high in the river basins lying in north-western region and parts of South India?

Answer:

Water percolates easily in alluvial soil construction is easy.
Northern states are mostly the agricultural states where the water is used for irrigation.
South India is hard in rocky terrain, percolation of the water becomes difficult, moreover, canal construction is costly because of topography.

Question 7.

Name the three states which have larger area under irrigation and why?

Answer:

The three states are:

Punjab
Haiyana
Western Uttar Pradesh

It is because:

Wheat and rice are grown mainly with the help of irrigation in these states.
Net irrigated area of Punjab and Haryana are irrigated through wells and tube wells.
These states utilize large proportion of their groundwater potential.
Canal irrigation is the biggest source of irrigation in North India.
In peninsular India, tank irrigation is mostly done.

Question 8.

What are the implications of using groundwater in drought-prone areas of Rajasthan, Gujarat, Maharashtra and Tamil Nadu?

Answer:

The over-use of groundwater resources has led to decline in its level.
Rajasthan and Maharashtra have increased fluoride concentration in groundwater.
This practice has led to increase in concentration of arsenic in West Bengal and Bihar.
This practice has increased salinity in the soil of Punjab and Haryana.

Question 9.

What are the four major problems in the development of water resources in India?

Answer:

Water resources in India faced many problems such as availability, quality, usage and management.

Availability: Water resources are excess in some regions such as West Bengal whereas it is deficient in other parts of the country like Rajasthan and peninsular India.
Quality: Water pollution is caused by domestic waste, industrial waste and chemical use in agriculture.
Usage: Underground water resources could be used in Northern India whereas in Gujarat, Maharashtra, West Bengal, it increases the concentration of arsenic, fluoride and salinity in the soil.
Management: The availability of fresh water is less and is also declining whereas the demand of water is getting rapid due to industrialization and urbanization, moreover inter-state water disputes are increasing. There are seepage losses and lack of improved irrigation facilities.

Question 10.

Why there is a need to conserve water resources?

Answer:

Increasing demand for agricultural sector, domestic use due to urbanisation and industrialisation & rise in population.
Sustainable development.
High cost of desalinisation.

Due to above reasons, we need to conserve water resources.

Question 11.

Give a few examples where water can be recycled and reused to improve the availability of fresh water.

Answer:

Use of water of lesser quality such as reclaimed waste-water would be an attractive option for industries.
Fire fighting and industrialization cooling to reduce their water cost.
Urban areas water after bathing and washing utensils can be used for gardening.
Water used for washing vehicle can also be used for gardening.

Long Answer Type Questions

Question 1.

What are the major sources of surface water?

Answer:

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. rate. Due to topographical, hydrological and other constraints, only about 690 cubic km (32 per cent) of the available surface water can be utilised. Water flow in a river depends on size of its catchment area or river basin and rainfall within its catchment area.

Precipitation in India has spatio temporal variation, and it is mainly concentrated in Monsoon season. Some of the rivers in the country like the Ganga, Brahmaputra, and the Indus have huge catchment areas. Precipitation is high in the catchment areas of the Ganga, the Brahmaputra and the Barak rivers, these rivers, although account for only about one-third of the total area in the country, have 60 per cent of the total surface water resources. A good percentage of water flow in south Indian rivers like the Godavari, the Krishna, and the Kaveri has been harnessed. The other sources of surface water like lakes, ponds and tanks are utilized. In south India, tank irrigation is common.

Question 2.

With the example of ‘Ralegan Siddhi’ show how watershed development projects are imperative for development.

Answer:

Ralegan Siddhi’ is a village in Maharashtra, which was under abject poverty. Transformation started with the initiative of an army personnel, who took up watershed development. Voluntary work by the villagers along with their monetary contribution changed the village from a poverty stricken village to a role model for others to emulate. Work began with a percolation tank. A youth group called Tarun Mandal was formed which worked to ban the dowry system, caste discrimination and other social evils.Cultivation of water intensive crops and practice of open grazing were banned. Crops with low water requirements were encouraged. Nyay Panchayat was set up to look in to the local problems. Utilising local resources, a school was contructed. The villagers want to buy land from adjoining villages for developmental purposes. The village transformed to a self reliant and sufficient village.

Question 3.

Give some possible solutions to water problem in India.

Answer:

In order to solve water problem in India constructive holistic approach should be adopted and implemented.

There is a wide scope to use rainwater harvesting technique to conserve precious water resource. It can be done by harvesting rainwater on rooftops and open spaces. Harvesting rainwater also decreases the community dependence on groundwater for domestic use.
Besides bridging the demand supply gap, it can also save energy to pump groundwater as recharge leads to rise in groundwater table. Urban areas can specially benefit from rainwater harvesting as water demand has already outstripped supply in most of the cities and towns.
Desalinization of water particularly in coastal areas and brackish water in arid and semi-arid areas.
Transfer of water from water surplus areas to water deficit areas through inter linking of rivers can be important remedies for solving water problem in India.
Pricing of water for households and communities should be considered more seriously.