CBSE Class 10 Science Management of natural resources Notes

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Class 10 Science Chapter 16 Management of Natural Resources notes cover the consequences of exploiting natural resources, coliform bacteria, pollution of the Ganga, the Ganga Action Plan, sustainable development, the three R's, forests and wildlife, stakeholders, water harvesting, dams, coal and petroleum, along with the intext and exercise questions with answers.

CHAPTER 16: MANAGEMENT OF NATURAL RESOURCES

Natural Resources

Natural resources can be broadly categorised into two types: exhaustible and non-exhaustible. Management of natural resources is all about their judicious use, so that exhaustible resources last for many generations to come and non-exhaustible resources are maintained in as pristine a form as possible.

Consequences of Exploitation of Natural Resources

Burning of fossil fuels creates air pollution. Excess carbon dioxide in the atmosphere leads to global warming. Polluting gases such as oxides of nitrogen and sulphur lead to acid rain, which is harmful for living beings. Acid rain is also harmful for monuments and buildings.
Excess exploitation of groundwater leads to a drastic fall in the water table. This is the reason many places experience acute shortage of drinking water.
Overuse of fertilisers and insecticides leads to soil pollution and soil erosion.
Many pollutants are directly flowed into water bodies. This has resulted in water pollution in many rivers, lakes and even in oceans.

Coliform Bacteria

Coliform bacteria originate as organisms in soil or vegetation and in the intestinal tract of warm-blooded animals (faecal coliforms). This group of bacteria has long been an indicator of water contamination and of the possible presence of intestinal parasites and pathogens. Coliform bacteria are relatively simple to identify, are present in much larger numbers than more dangerous pathogens, and react to the natural environment and treatment processes similarly to pathogens. By observing coliform bacteria, the increase or decrease of many pathogenic bacteria can be estimated.

Where are these bacteria found?

Sources of bacterial pollution include runoff from woodlands, pastures and feedlots; septic tanks and sewage plants; and animals and wild fowl. Domestic animals contribute heavily to the bacterial population. Many coliform bacteria may be deposited directly into natural streams from waste in water and runoff from areas with high concentrations of animals or humans.

How could coliform bacteria enter a water system?

The most likely sources come from where the water is used: the tap, sink or unclean containers. Another is backflow from a contaminated source, such as a sink-top carbon filter, a bucket of water, or a puddle at the end of a hose. Also, reduced pressure or suction in long water lines can draw bacteria-laden water or soil into pipes through joints.
However, the presence of bacteria is not always related to illness. The water may have been contaminated through improper sampling. Children may become ill because of unsanitary conditions in the home. Questions to ask include who sampled the water and how, how sanitary the food handling and personal hygiene practices are, and whether the children wash regularly. These are more likely routes for contamination than the water itself.

Pollution of the Ganga

The Ganga flows for over 2500 km from Gangotri in the Himalayas to Ganga Sagar in the Bay of Bengal. It is being turned into a drain by more than a hundred towns and cities in Uttar Pradesh, Bihar and West Bengal, which pour their garbage and excreta into it. Largely untreated sewage is dumped into the Ganga every day. Other human activities also add to the pollution, such as bathing, washing of clothes and immersion of ashes or unburnt corpses. Industries contribute chemical effluents to the pollution load, and their toxicity kills fish in large sections of the river.

Ganga Action Plan (GAP)

Inertia in taking action to reduce pollution stemmed largely from a widespread belief that the Ganga, as a holy river, had the ability to purify all that came into contact with it. There is some scientific evidence for the Ganga's high capacity to assimilate (biodegrade) a large amount of organic waste, including pathogens. However, no river can sustain its self-purifying power under this kind of over-use, misuse and abuse.
The Ganga Action Plan (GAP) originated from the personal intervention and interest of the late Prime Minister Mrs Indira Gandhi. She directed the Central Board for the Prevention and Control of Water Pollution, now the Central Pollution Control Board (CPCB), to carry out a comprehensive survey of the situation in 1979. The CPCB published two comprehensive reports, which formed the base for GAP in October 1984. The plan was not presented to the nation formally, due to the assassination of Mrs Indira Gandhi.
In February 1985, the Central Ganga Authority (CGA), with the Prime Minister as Chairman, was formed, with an initial budget of Rs 350 crore to administer the cleaning of the Ganga and restore it to pristine condition. In June 1985, the Ganga Project Directorate (GPD) was established as a wing of the Department of Environment. GAP was launched on June 14, 1986 by Sh Rajiv Gandhi at Varanasi.

Sustainable Development

Development is necessary for economic growth, but development often comes with a price in the form of environmental damage. Sustainable development means following practices that save the environment from damage. This is necessary for keeping the earth in good shape, so that future generations can also enjoy the bounty of nature.

Three R's (Reduce, Recycle and Reuse)

Reduce: We should reduce the consumption of various resources wherever possible. For example, we can reduce the consumption of electricity by switching off lights and other appliances when they are not required. While leaving the home, one should always check for fans and lights and switch them off. This can not only help in saving electricity but also in saving the fuels which are utilised in electricity production. We should immediately repair a leaking tap so that precious water can be saved.
Recycle: Many items can be recycled again and again. Recycling reduces the demand for natural resources. For example, by recycling paper we reduce the demand for wood and help save forests.
Reuse: Many items can be reused many times. For example, old newspapers can be used for packing, old envelopes can be used for rough work, and old plastic bottles can be used for many other purposes.

INTEXT QUESTIONS (PAGE NO. 269)

Q1. What changes can you make in your habits to become more environment friendly?

Answer: We should try to understand how our choices affect the environment. The use of renewable resources and biodegradable materials should be promoted. For example, (a) use paper bags instead of plastic, (b) use sources of energy such as LPG or alcohol, which do not cause pollution, and (c) use substances that can be recycled or reused.

Teacher's Note:
a) Choosing biodegradable and reusable items reduces the load on landfills and water bodies.
b) Cleaner fuels such as LPG reduce air pollution compared with coal or wood.

Q2. What would be the advantages of exploiting resources with short-term aims?

Answer: Natural resources are limited, so they must be used judiciously. Exploiting them for short-term gains leads to depletion of resources for the present generation and for generations to come. Hence, there are hardly any advantages of exploiting natural resources for short-term gains.

Teacher's Note:
a) Short-term exploitation gives quick profit, but it harms the resource base for everyone later.
b) Sustainable use balances present needs with future availability.

Q3. How would these advantages differ from the advantages of using a long-term perspective in managing our resources?

Answer: With a long-term perspective, resources last for the generations to come. This management ensures a uniform distribution among people and conserves natural resources for many years rather than just a few, as happens with a short-term approach.

Teacher's Note:
a) A long-term view protects the resource for future users, not only for today.
b) It also spreads the benefits more fairly across the community.

Q4. Why do you think there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?

Answer: Natural resources of the Earth must be distributed uniformly among the people, so that each person gets a fair share. Human greed, corruption and the influence of the rich and powerful work against an equitable distribution of resources.

Teacher's Note:
a) Unequal access to resources creates conflict and poverty.
b) Good governance and transparent allocation help achieve fair distribution.

Forest and Wildlife

Conservation of forests and wildlife is necessary to protect biodiversity. Loss of biodiversity leads to ecological imbalance. Any conservation effort for forests and wildlife must keep the interests of all stakeholders in mind.

Stakeholders

The stakeholders who are directly or indirectly affected by forests are:
1. People living in or around forests, as they depend on forest produce for their livelihood.
2. The forest department, which is the owner of the forest land.
3. Industrialists who depend on forests for raw materials. For example, the beedi industry needs kendu leaves, and wood is used as a raw material in many industries.
4. Wildlife and nature enthusiasts.

Before the beginning of colonial rule in India, forest dwellers were free to use forest resources as they wished. This changed when the British rulers took control of the forests and restricted the access of forest dwellers to forest resources. This created huge problems for many people who had traditionally depended on forests for their survival.
After Independence, the forest department took over, but the interests of forest dwellers continued to be ignored for a long time. Forests were cut for timber for railways and construction. The cleared forests were replaced by eucalyptus plantations, which led to monoculture. Growing a single species is called monoculture, and it disturbs the biodiversity of an area.

Local People and Forest Conservation

Involvement of local communities is necessary for any conservation effort.
Bishnoi community of Rajasthan: Amrita Devi Bishnoi is still remembered with reverence for the way she fought for protecting the khejri trees in Khejrali village. She, along with 363 other people, sacrificed her life for the protection of khejri trees in 1731. The Amrita Devi Bishnoi National Award for Wildlife Conservation is named in her honour.
Nomadic herders of the Himalayas: The nomadic herders used to graze their animals near the Great Himalayan National Park, bringing herds down the valley every summer. When the National Park was created, the herders were stopped from grazing in the protected area. Without grazing, the grasses grew very tall, fell over and prevented fresh growth. This shows that proper conservation cannot be carried out by excluding and alienating local people from forests.
Chipko Movement: The Chipko Movement began in the early 1980s in the village of Reni in the Garhwal district. The women of the village hugged trees to prevent their cutting by contractors. The movement spread to other parts of India and was instrumental in stopping deforestation to a large extent.

Arabari's Example of People's Participation in Forest Management

In 1972, the forest department realised its mistake while reviving the degraded sal forests of the Arabari forest range in Midnapore district of West Bengal. Earlier methods of policing and surveillance had failed, as they often led to clashes with local people and alienated them from the conservation programme. A forest officer, A. K. Banerjee, involved local people in the revival of 1,272 hectares of forest. In return, the villagers were given employment in silviculture and harvesting, were given 25% of the harvest, and were allowed to gather firewood and fodder against a nominal payment. Because of the active participation of the local community, the Arabari sal forest revived remarkably. By 1983, the value of the forest had risen to Rs 12.5 crore.

INTEXT QUESTIONS (PAGE NO. 273)

Q1. Why should we conserve forests and wildlife?

Answer: We should conserve forests and wildlife to preserve biodiversity (the range of different life-forms) and avoid the loss of ecological stability. A large number of tribes live in and around the forests, and their lives would be affected if forests were not conserved. Without proper management of forests and wildlife, the quality of soil, the water sources and even the amount of rainfall may be affected. Without forests and wildlife, life would become impossible for human beings.

Teacher's Note:
a) Forests regulate water supply, soil quality and rainfall, so their loss affects everyone.
b) Biodiversity keeps ecosystems stable, and every species has a role.

Q2. Suggest some approaches towards the conservation of forests.

Answer: Afforestation is one of the most important approaches. Besides this:
(a) Deforestation should be banned.
(b) People should be made more aware of the importance of forests.
(c) Protected areas should be managed by local people, which would be quite efficient.
(d) National parks and sanctuaries should be formed to conserve biodiversity.
(e) Hunting should be banned, and laws should be made against hunting.
(f) There should be proper laws for the exploitation of forest resources.

Teacher's Note:
a) Involving local people improves both protection and livelihoods.
b) Laws and awareness work together, because laws alone cannot protect forests.

Water for All

Water harvesting is an age-old concept in India. Khadins, tanks and nadis in Rajasthan, bandharas and tals in Maharashtra, bundhis in Madhya Pradesh and Uttar Pradesh, ahars and pynes in Bihar, kulhs in Himachal Pradesh, ponds in the Kandi belt of the Jammu region, eris (tanks) in Tamil Nadu, surangams in Kerala, and kattas in Karnataka are some of the ancient water harvesting and conveyance structures that are still in use at many places. These traditional structures are location specific and have been perfected over a long period. They take into account the local geography and the needs of the local people, and hence are highly efficient.
Traditional water harvesting structures usually focus on recharging groundwater rather than making an open reservoir. This has several advantages. Unlike surface water, groundwater does not evaporate, so evaporation losses are prevented. Groundwater does not provide a breeding ground for mosquitoes, which is good for public health. It is also relatively protected from contamination by human activities.

Dams

A dam is a barrier that impounds water or underground streams. Reservoirs created by dams suppress floods and provide water for irrigation, human consumption, industrial use, aquaculture and navigation. Hydropower is often used together with dams to generate electricity. Dams mainly retain water, while structures such as floodgates and levees (also known as dikes) are used to manage or prevent water flow into specific land regions.

Advantages of dams:
Once a dam is constructed, electricity can be produced at a constant rate.
If electricity is not needed, the sluice gates can be shut to stop electricity generation, and the water can be saved for use when demand is high.
Dams are designed to last many decades, so they can contribute to electricity generation for many years.
The lake formed behind the dam can be used for water sports and leisure activities. Large dams often become tourist attractions in their own right.
The lake's water can be used for irrigation.
Energy can be stored in the form of water until needed, and it is released to produce electricity.
Electricity produced by dam systems does not produce greenhouse gases and does not pollute the atmosphere.

Disadvantages of dams:
Dams are extremely expensive to build and must be built to a very high standard. The high cost means they must operate for many decades to become profitable.
The flooding of large areas of land destroys the natural environment.
People living in villages and towns in the valley to be flooded must move out and lose their farms and businesses. In some countries, people are forcibly removed so that hydropower schemes can go ahead.
Building large dams can cause serious geological damage. For example, the building of the Hoover Dam in the USA triggered a number of earthquakes and depressed the earth's surface at its location.
Although modern planning and design of dams is good, old dams have been known to breach under the weight of the water in the lake. This has led to deaths and flooding.
A dam built across a river in one country can put the water supply of the next country under its control. This can lead to serious problems between neighbouring countries.
Building a large dam alters the natural water table. For example, the Aswan Dam in Egypt has altered the water table, and this is slowly damaging many of its ancient monuments, as salts and destructive minerals are deposited in the stonework from rising damp caused by the changing water table level.

Water Harvesting

Water harvesting is the act of collecting and storing rainwater for future use. It can be done in areas of low or high rainfall using tanks and cisterns. Collecting rainfall reduces run-off, flooding and erosion in prone areas. This is especially relevant in urban areas, where land has been built over and rainwater run-off has nowhere to go, which can result in flooding. In rural areas, when water is collected, the run-off into rivers and ponds is reduced, which slows the contamination from fertilisers and pesticides. Collected water can be treated and used as drinking water where drinking water is scarce. It can also be used for non-drinking purposes such as flushing toilets. Homeowners and farmers can reduce their water bills and their use of groundwater by using collected water for irrigating crops, lawns and trees. This conserves groundwater levels, which are precariously low in many areas.

Why adopt rainwater harvesting?
It reduces the run-off volume and the peak flow, which helps mitigate floods.
It recharges groundwater, which is a solution to the water shortage problem in winter.
It reduces the cost per litre of water, because the large amount of power used to pump water from underground aquifers can be saved.

INTEXT QUESTIONS (PAGE NO. 276)

Q1. Find out about the traditional systems of water harvesting/management in your region.

Answer: There are many traditional methods of water harvesting and management, such as khadins, ponds and tals. Wells have been dug for drinking water and irrigation. Canals have been developed, and water reservoirs have been built by the government to provide proper drinking water.

Teacher's Note:
a) Traditional systems were designed for the local terrain and rainfall, which is why they remain efficient.
b) Check with local elders or the panchayat to find the systems used in your own area.

Q2. Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.

Answer: In plains, water harvesting structures are crescent-shaped earthen embankments. These are low, straight, and concrete. In hilly regions, the canal irrigation system called Kulhs is used for water harvesting. It collects rainwater in a stream, which is then diverted into man-made channels down the hillsides.

Teacher's Note:
a) Plains use embankments to hold water, while hills use gravity-fed channels because of the slope.
b) The printed text describes the plains structure as "low, straight and concrete", but traditional embankments are earthen.

Q3. Find out the source of water in your region/locality. Is water from this source available to all people living in that area?

Answer: The source of water in our region is groundwater. Water from this source is available to all the people living in that area.

Teacher's Note:
a) The answer depends on the locality, so the answer should be checked against your own area.
b) Groundwater availability can fall when the water table drops from over-extraction.

Coal and Petroleum

Coal and petroleum are the main energy resources for us. Since they are exhaustible, we need to find alternative sources of energy. Scientists are working on developing alternative energy sources so that dependence on coal and petroleum can be reduced. Some examples are:
Solar energy is being used to produce electricity at many places. The technologies for solar energy are still costly, but future prospects look bright.
A fuel cell is another development that may help replace internal combustion engines in automobiles.
Hydrogen is being used as fuel in buses and cars in many countries. When used as a fuel, hydrogen produces water as a by-product, so it can be an environment-friendly fuel.

EXERCISE QUESTIONS (PAGE NO. 278-279)

Q1. What changes would you suggest in your home in order to be environment-friendly?

Answer:
(i) Plant different kinds of shade-giving plants, fruit-bearing and vegetable-bearing plants.
(ii) Use less insecticides and pesticides.
(iii) Store food properly to avoid spoilage and prevent wastage.
(iv) Provide a proper drainage system so that water passes into the drains.
(v) Dispose of water properly.
(vi) Cover dustbins and other waste products properly, and do not dump garbage around the house.
(vii) Adopt proper sanitary and hygiene methods.

Teacher's Note:
a) Proper waste covering and drainage stop breeding of mosquitoes and flies.
b) Plants around the home also reduce heat and improve air quality.

Q2. Can you suggest some changes in your school which would make it environment friendly?

Answer:
(i) Plant different kinds of shade-giving and fruit-bearing trees, and also plant flowering plants.
(ii) Do not spread waste material, used paper, foil or empty packets around the school.
(iii) Keep the water facility in good condition.
(iv) Rooms should be properly ventilated.
(v) Provide proper dustbins for the disposal of waste.
(vi) Keep big and clean playgrounds.

Teacher's Note:
a) Student participation in cleaning and planting makes the changes last.
b) Good ventilation reduces the need for artificial cooling and saves electricity.

Q3. We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?

Answer: The forest department of the government should have the authority to decide the management of forest produce. The forest department is the caretaker of the forest land and is responsible for any damage to the forest.

Teacher's Note:
a) The forest department holds legal ownership and accountability for the forest land.
b) Local communities should still be consulted, because they depend on forest produce.

Q4. How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?

Answer:
(a) Forest and wildlife: (i) use forest products judiciously; (ii) control the felling of trees for paper, timber and other purposes; (iii) ban the killing of wild animals for their skin and other parts; (iv) practise afforestation; (v) give the management of forests to local people; (vi) preserve the biodiversity we have inherited.
(b) Water resources: (i) repair leaking taps; (ii) do not dump water from industries directly into rivers; (iii) minimise the use of insecticides and pesticides, which are washed away with rain and contaminate river and groundwater; (iv) promote methods such as rainwater harvesting and the construction of canals. Construction of dams may also prove beneficial.
(c) Coal and petroleum: (i) minimise the use of coal and petroleum as sources of energy; (ii) use CNG or LPG as fuel in automobiles; (iii) use renewable sources such as solar, hydro, wind and tidal energy. It is better to walk a short distance rather than go by car or scooter.

Teacher's Note:
a) Individual actions add up, so small changes in daily habits make a real difference.
b) The printed answer has the spelling "cannal" and "timer", which are corrected here.

Q5. What can you as an individual do to reduce your consumption of the various natural resources?

Answer:
Natural resources such as water, forests, coal and petroleum, etc. are important for the survival of human beings. The ways in which we can reduce the consumption of various natural resources are as follows:
(i) Stop cutting trees (deforestation).
(ii) Use recycled paper to reduce the cutting down of trees.
(iii) Do not waste water.
(iv) Practise rainwater harvesting.
(v) Practise car pooling to avoid excessive use of petroleum.
(vi) Use alternative sources of energy such as hydro energy and solar energy.

Teacher's Note:
a) Reducing consumption lowers the demand on forests, water and fuel together.
b) Car pooling and public transport cut petrol use and air pollution.

Q6. List five things you have done over the last one week to - (a) conserve our natural resources. (b) increase the pressure on our natural resources.

Answer:
(a) Conserve our natural resources: (i) limited use of water; (ii) plantation in free areas; (iii) irrigation of plants; (iv) limited use of petrol and diesel; (v) used smokeless fuel.
(b) Increase the pressure on our natural resources: (i) extra use of water; (ii) lighting day and night; (iii) unnecessary car trips; (iv) burning of polythene and waste; (v) destroying plants.

Teacher's Note:
a) Answers depend on the student's own week, so these are sample entries.
b) Burning polythene releases toxic gases and should be avoided.

Q7. On the basis of the issues raised in this chapter, what changes would you incorporate in your life-style in a move towards a sustainable use of our resources?

Answer:
(i) Stop cutting trees and practise planting trees.
(ii) Stop using plastic and polythene bags for carrying goods.
(iii) Use recycled paper.
(iv) Put biodegradable and non-biodegradable waste into separate bins.
(v) Waste as little water as possible, and repair leaking taps.
(vi) Practise rainwater harvesting.
(vii) Avoid vehicles for short distances; walk or cycle instead. For long distances, take a bus rather than a personal vehicle.
(viii) Switch off electrical appliances when not in use.
(ix) Use fluorescent tubes in place of bulbs to save electricity.
(x) Take the stairs and avoid lifts.
(xi) In winter, wear an extra sweater instead of using heaters.

Teacher's Note:
a) The printed list repeats item (vi); the items here are numbered in sequence.
b) Each change reduces demand on a resource such as water, forests, electricity or fuel.