Chapter 31A Water Conservation at Different Levels

NIOS Class 12 Environmental Science Chapter 31A

INTEXT QUESTIONS 31.1

1. List at least three reasons why water conservation is important.

Ans: Water is a scarce resource. It is important for the survival of all living beings. Moreover, usable water is very meagre on earth as the major portion available is saline water in the ocean and seas. It needs to be conserved.

2. List two irrigation practices which reduce water requirements.

Ans:

Drip irrigation is an efficient method of irrigation in which a limited area near the plant is irrigated by dripping water. It is a suitable method for any area and especially for water-scarce areas. This method is particularly useful in row crops.
The sprinkler method is also suitable for such water-scarce areas. About 80% water consumption can be reduced by this method, whereas drip irrigation can reduce water consumption by 50 to 70 %.

3. List two benefits of the reuse of water.

Ans: Reuse of treated wastewater has the following benefits:

Make up for the shortage of water supply (reduces demand for good quality water)
Reduces the wastewater discharge, thus reducing water pollution.
Results in cost reduction.

4. How can transpirational loss be reduced?

Ans: Transpiration losses can be reduced by reducing air movement over a crop by putting wind breaks and evolving such types of crops which possess xerophytic adaptations.

5. What are the benefits of contour farming?

Ans: Two benefits:

1. Conserve water by holding it for a longer time in the field
2. Since it prevents runoff water too fast, it prevents soil erosion.

INTEXT QUESTIONS 31.2

1. What is a watershed?

Ans: A Watershed is an area that contributes water to a stream or a water body through runoff or an underground path.

2. How do forests reduce the risk of floods?

Ans: Forests prevent rain, and excellent filler and excess water is absorbed through the roots of the forest trees.

3. List any two ways in which forests help in maintaining the quality of water.

Ans: Water moves through soil, and the little layers are excellent filters and relatively pure. Waters from forested areas are not only low in foreign substances, but they are also relatively high in oxygen and low in unwanted chemicals.

4. What is achieved by single-stem harvesting?

Ans: The process where only one tree is felled at any one point, and the small gap so created is soon sealed by the outward growth of its neighbour, is called single stem technology.

INTEXT QUESTIONS 31.3

1. How can you save water at your personal level? List at least 6 ways.

Ans:

Take short showers or a bucket for bathing.
Turn off the taps while brushing and shaving.
Use basins to clean vegetables and fruits.
Promptly repair any plumbing issues at home.
Invest in rainwater harvesting at home.

2. There are many examples in Gujarat of individual and community action on rainwater harvesting. List two such activities.

Ans:

Villagers in Gandhigram developed a group, Gram Vikas Mandal, that took a loan and personal contributions to build a check dam on the nearby river. Apart from the dam, the villagers also undertook a micro-watershed project. Due to these water retention structures, the villagers now have sufficient drinking water, and 400 ha of land, which earlier lay barren, have come under irrigation.
Students of Bhavnagar University, under the guidance of the then Vice Chancellor of the university, Prof. Vidyut Joshi, initiated the digging of a percolation tank in the university premises. About 650 students, 245 teachers and other employees of the university worked as voluntary labour. During the following monsoon, all the bore wells in the university as well as those in the adjoining areas were recharged.

3. Government is promoting conservation of water. List any two reasons of such promotions.

Ans: The urban water economy is seen as wasteful and highly polluting. The importance of applying the polluter pays principle to domestic users in urban areas must be recognised. In many parts of our country, the water is polluted by discharges of domestic or industrial effluents. There is an urgent need to implement the anti-pollution law. The quality of groundwater is a very important concern, as it supports more than 50% of agriculture even today.

4. List the achievements of Tarun Bharat Sangh in context of water conservation.

Ans:

It is a seemingly simple two-step programme. First, revive vegetation on barren hill slopes and second, build small water catchments in the valleys and the plains. The efforts resulted in:

Dead rivers begin to flow.
Agriculture becomes possible around the year.
Impoverished villagers, labouring in cities, return, and families are reunited.
Wearying labour, like fetching water, gives way to positive developmental work.
With enough water and fodder, income from animal husbandry begins to flow.
Nutrition levels rise, and public health improves.
Wooded hills welcome back wildlife that round off forests’ wholeness.
People get rid of insecurities, come together to address other issues of life, like education and local governance.
Awareness and confidence enable micro-credit schemes that lower the cost of households and start small enterprises.
People with leisure turn to crafts, reviving folk practices like herbal medicine and community welfare.
When small communities like these succeed, the government itself wakes up and development becomes what it should be: ground-up, instead of top-down.

TERMINAL EXERCISE

1. Why is water conservation important in India

Ans: India is a developing country with a vast territory, complex topography, varied climate and a large population. The precipitation and runoff in the country are not only unevenly distributed, but also uneven with regard to the time of distribution of water during the year. Frequent floods, drought and unstable agricultural production have always been a serious problem. Water. A growing population and consequent need for an increase in food production, requiring an increasing area of agricultural fields and irrigation, are resulting in overuse of water. Due to the overexploitation of water resources, it has become scarce in many parts of our country. Thus, water conservation is of great importance to the economic, social and cultural development in India.

2. Name a few important methods of water conservation.

Ans:

(a) Conservation by surface water storage
(b) Conservation of rainwater
(c) Groundwater conservation
(d) Catchment area protection (CAP)
(e) Inter-basin transfer of water
(f)Adoption of drip sprinkler irrigation
(g) Management of the growing pattern of crops
(h) Reducing evapotranspiration
(j) Recycling of water

3. What an individual can do for water conservation at the household level.

Ans: Some of the ways for improving the efficiency of water use at the household level are:

Reducing wastage-leaking pipes, means that a lot of water never reaches the people. In Delhi estimated losses are 35-40 %.
Closing of taps while not in use.
Better irrigation techniques – irrigation systems waste up to 70% water used. In drip irrigation, water loss is significantly less.
Use low flush toilets-reducing the amount of water used each time the lavatory is flushed.
Build latrines and compact toilets which can turn human waste into clean, useful manure- this is much cheaper than connecting toilets to a piped sewage line.
Use bowls to wash vegetables, dishes instead of running the tap.
Greater use of recycled water, ‘grey water’, in the home. Instead of using potable or treated water,r use bath and shower water for watering the plants.
Use a washing machine or dishwasher when it is fully loaded.

4. How does watershed management help promote water conservation?

Ans: A Watershed is an area that contributes water to a stream or a water body through run-off or an underground path. The region from which surface water flows into a river, a lake, a wetland or other body of water is called its watershed or drainage basin. Watershed management is a technique for the conservation of water and soil in a watershed. The presence of water in soil is essential for the growth of plants and vegetation. Forests and their associated soils and litter layers are excellent filters as well as sponges, and water that passes through this system is relatively pure.

A watershed is an area through which a water body gets its water. Protection of forests and vegetation helps conservation of water in a watershed. The water passing through a forested watershed is generally clean.

5. What is rainwater harvesting? How does it help conserve water?

Ans: Rainwater harvesting, simply put, is putting water back into soil where it is stored in underground rivers and reservoirs so that it can be drawn when needed.

6. Explain in brief the example from Gujarat on rainwater harvesting

Ans:

Villagers in Gandhigram developed a group, Gram Vikas Mandal, that took a loan and personal contributions to build a check dam on the nearby river. Apart from the dam, the villagers also undertook a micro-watershed project. Due to these water retention structures, the villagers now have sufficient drinking water, and 400 ha of land, which earlier lay barren, have come under irrigation.
Students of Bhavnagar University, under the guidance of the then Vice Chancellor of the university, Prof. Vidyut Joshi, initiated the digging of a percolation tank in the university premises. About 650 students, 245 teachers and other employees of the university worked as voluntary labour. During the following monsoon, all the bore wells in the university as well as those in the adjoining areas were recharged.

7. What are the benefits of rainwater harvesting?

Ans:

The infrequent rain, if harvested over a large area, can yield a considerable amount of water.
Contour farming is an example of such a harvesting technique involving water and moisture control at a very simple level.
It often consists of rows of rocks placed along the contour of steps.
Runoff captured by these barriers also allows for retention of soil, thereby serving as an erosion control measure on gentle slopes.
This technique is especially suitable for areas having rainfall of considerable intensity, spread over a large part, i.e. in the Himalayan area, north north-east states and Andaman and Nicobar islands.
In areas where rainfall is scanty and for a short duration, it is worth attempting these techniques, which will induce surface runoff, which can then be stored.

8. What are the main attributes of groundwater?

Ans: Attributes of groundwater

There is more groundwater than surface water.
Less expensive and an economic resource, and available almost everywhere.
Sustainable and reliable source of water supply.
Relatively less vulnerable to pollution.
Free of pathogenic organisms.
Needs little treatment before use.
No conveyance losses in underground-based water supplies.
Has low vulnerability to drought.
Is the key to life in arid and semi-arid regions.
It is a source of dry weather flow in some rivers and streams.

9. Name a few initiatives of the Government on water conservation.

Ans: On water conservation following main efforts can be noted.

National Water Policy 2002 strongly emphasises the conservation of water.
Efforts to retain rainwater on land through various schemes.
The construction of a large number of dams on various river systems.
Interlinking of rivers (proposed).
Promotion of bunds at the village level.
Promotion of rainwater harvesting.
Promotion of the reuse and recycling of wastewater.
Steps to protect water quality.
Drought-proofing the future.

10. How has Tarun Bharat Sangh changed the face of a few villages in Rajasthan?

Ans: It is a seemingly simple two-step programme. First, revive vegetation on barren hill slopes and second, build small water catchments in the valleys and the plains. The efforts resulted in:

Dead rivers begin to flow.
Agriculture becomes possible around the year.
Impoverished villagers, labouring in cities, return, and families are reunited.
Wearying labour, like fetching water, gives way to positive developmental work.
With enough water and fodder, income from animal husbandry begins to flow.
Nutrition levels rise, and public health improves.
Wooded hills welcome back wildlife that round off forests’ wholeness.
People get rid of insecurities, come together to address other issues of life, like education and local governance.
Awareness and confidence enable micro-credit schemes that lower the cost of households and start small enterprises.
People with leisure turn to crafts, reviving folk practices like herbal medicine and community welfare.
When small communities like these succeed, the government itself wakes up and development becomes what it should be: ground-up, instead of top-down.