"AKC SCIENCE CLASSES"
CLASS 10 TH (CBSE AND MP BOARD)
CHAPTER 16
MANAGEMENT OF NATURAL RESOURCES
INTEXT QUESTIONS AND ANSWERS
NCERT INTEXT QUESTIONS (PAGE NO. 269)
Q.01:- What changes can you make in your habits to become more environment friendly?
Ans:- Segregate waste into recyclable and non-recyclable parts. Switch off fans and lights when not required. Use air conditioners, geysers and other appliances efficiently. Walk for nearby shops instead of using vehicles.
Reuse paper, plastic and glass bottles. Reuse water from washing clothes for cleaning purposes. Use soaps and detergents that require less water to rinse.
Q.02:- What would be the advantages of exploiting resources with short term aims?
Ans:- It provides immediate advantages that fulfil basic current needs.
Q.03:- How would these advantages differ from the advantages of using a long term perspective in managing our resources?
Ans:- The advantage of using long term perspective is the basis of sustainable management of natural resources. This way the resources can be used for the benefit of the present generation and also conserved for the benefit and aspirations of future generations. Surely, long term perspective has a definite advantage over short term perspective for use of natural resources.
Q.04:- Why do you think there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?
Ans:- Presently rich and influential people are getting maximum benefit and share of resources. Equitable distribution will benefit both poor as well as rich people.
Power and money are the two forces which are working against an equitable distribution of resources.
NCERT INTEXT QUESTIONS (PAGE NO. 273)
Q.01:- Find out about the tradition systems of water harvesting/management in your region.
Ans:- Water harvesting technique are highly localised and differ from place to place. In India the following water harvesting techniques are used areawise :-
- Khadins and nadis in Rajasthan.
- Bandharas and tals in Maharashtra.
- Bandhis in M.P. and U.P.
- Ahars and pynes in Bihar.
- Kulhu in Himachal Pradesh.
- Ponds in the Kandi belt of J.K.
- Eris (tanks) in Tamil Nadu.
- Surangams in Kerala.
- Kattas in Karnataka.
Ans:- Some of the system in hilly areas, plains and plateau regions are as follows :-
Hilly Areas :-
(a) Zings are water harvesting structures found in ladakh. They are small tanks, in which collects melted glacier water. Essential to the system is the network of guiding channels that brings the water from the glacier to the tank. As glaciers melt during the days, the channels fill up with a trickle that in the afternoon turns into flowing water. The water collects towards the evening, and is used the next day.
(b) Bamboo pipes :- Meghalaya has an ingenious system of tapping of stream and spring water by using bamboo pipes to irrigate plantations. About 18-20 litres of water entering the bamboo pipe system per minute gets transported over several hundred metres and finally gets reduced to 20-80 drops per minutes at the site of the plant. This 200 year old system is used by the tribal farmers of Khasi and Jaintia hills to drip-irrigate their black pepper cultivation. Bamboo pipes are used to divert perennial springs on the hilltops to the lower reaches by gravity. The channel sections, made of bamboo, divert and convey water to the plot site where it is distributed without leakage into branches, agin made and laid out with different forms of bamboo pipes. The last channel section enables the water to be dropped near the roots of the plant.
(c) Kulhs are a traditional irrigation system in Himachal Pradesh. The system consists of a temporary headwall (constructed usually with river boulders) across a khud (ravine) for storage and diversion of the flow through a canal to the fields. The kulh is provided with moghas (kuchcha outlets) to draw out water and irrigate nearby terraced fields. The water flows from field to field and surplus water, if and, drains back to the khud.
(d) The zabo (the word means 'impounding run-off') system is practiced in Nagaland in north-eastern India. The rain falls on a patch of protected forest on the hilltop; as the water runs off along the slope; it passes through various terraces. The water is collected in pond like structures in the middle terraces; below are cattle yards, and towards the foot of the hill are paddy fields, where the run-off ultimately meanders into.
(e) Khatris are the structures, about 10 ✖ 12 feets in size and six feet deep carved out in the hard rock mountain. These traditional water harvesting structures are found in Hamirpur, Kangra and Mandi districts of Himachal Pradesh. There are two types of khatris : one for animals and washing purposes in which rain water is collected from the roof through pipes and other sued for human consumption in which rain water is collected by seepage through rocks.
(f) Kulhs are water channels found in precipitous mountain areas. These channels carry water from glaciers to villages in the Spiti valley of Himachal Pradesh. Where the terrain in muddy, the kul is lined with rocks to keep it from becoming clogged. In the Jammu region too, similar irrigation systems called kulhs are found.
Plains :-
(a) Eris (tanks) in Tamil Nadu have played several important roles in maintaining ecological harmony as flood-control systems, preventing soil erosion and wastage of run-off during periods of heavy rainfall, and recharging the ground water in the surrounding areas.
(b) Baoris or bers are community wells, found in Rajasthan, that are used mainly for drinking. Most of them are very old and were built by banjaras (mobile trading communities) for their drinking water needs. They can hold water for a long time because of almost negligible water evaporation.
(c) Kuis are found in western Rajasthan, these are 10-12 m deep pits dug near tanks to collect the seepage. The mouth of the pit is usually made very narrow. This prevents the collected water from evaporating. The pit gets wider as it burrows under the ground, so that water can sleep in into a large surface area. The openings of these entirely kuchcha (earthen) structures are generally covered with planks of wood, or put under lock and key.
(d) Jhalaras were human made tanks, found in Rajasthan and Gujarat, essentially meant for community use an for religious rites. The jhalaras are rectangular in shape with steps on three or even on all the four sides of the tank. The steps are built on a series of levels. The jhalaras collect subterranean seepage of a talab or a lake located upstream.
(e) Paar is a common water harvesting practice in the western Rajasthan region. It is a common place where the rain water flows from the agar (catchment) and in the process percolates into the sandy soil.
(f) Virda are shallow wells dug in low depressions called jheels (tanks). They are found all over the Banni grasslands, a part of the Great Rann of Kutch in Gujarat. These structures harvest rain water. Essentially, the structures use a technology that helps to separate potable fresh water from non-potable salt water. After rain water infiltrates the soil, it gets stored at a level above the salty ground water because of the difference in their density. A structure is built to reach down (about 1m) to this upper layer of accumulated rain water. Between these two layers of sweet and saline water, there exists a zone of brackish water. As fresh water is removed, the brackish water upwards, and accumulates towards the bottom of the virda.
(g) A khadin, also called a dhora, is an ingenious construction designed to harvest surface run-off water for agriculture. Its main feature is a very long (100-300 m) earthen embankment built across the lower hill slopes lying below gravelly uplands. Sluices and spillways allow excess water to drain off. The khadin system is based on the principle of harvesting rain water on farmland and subsequent use of this water-saturated land for crop production.
Plateaus :-
(a) Bandharas are the check dams or diversion weirs built across rivers. A traditional system found in Maharashtra, their presence raises the water level of the rivers so that it begins to flow into channels. They are also used to impound water and form a large reservoir. Where a bandhara was built cross a small stream, the water supply would usually last for a few months after the rains.
(b) Johads are small earthen check dams that capture and conserve rain water, improving percolation and ground water recharge.
(c) A rapat is a percolation tank, with a bund to impound rain water flowing through a watershed and a waste weir to dispose of the surplus flow. If the height of the structure is small, the bund may be built of masonry structures. Rapats and percolation tanks do not directly irrigate land, but recharges well within a distance of 3-5 kms downstream. Silting is a serious problem with small rapats and the estimated life of a rapat varies from 5 to 20 years.
(d) Tanks, called kere in kannada method of irrigation in the Central Karnataka Plateau, and were fed either by channels branching off from anicuts (check dams) built across streams, or by streams in valleys. The outflow of one tank supplied the next all the way down the course of the stream; the tanks were built in a series, usually situated a few kilometre apart. This ensures
- no wastage through overflow, and
- the seepage of a tank higher up in the series would be collected in the next lower one.
Ans:- The main source of water in a city like New Delhi is river. Water in Delhi comes from Yamuna which is then treated and is supplied to the residents through a system of water pipes. Some water is also taken from the ground through bore-wells. This water is available to all living in some areas not approved by municipal authorities. In these areas, the ground water is the main source which is obtained through hand pumps and tube-walls.
In villages and distant areas, the source of water are river, wells, lake, and ponds.
