66) What are the causes of river pollution? Suggest some ways to overcome them? Or Analyse the causes that result into river pollution. Or Mention any three causes of increasing pollution in rivers. Or Why the water pollution is a significant danger? Explain.
Answer: Water pollution is a great concern of contemporary world. Water pollution in rivers cause significant danger to human health. Human beings depend on rivers for many daily activities and neccessities like drinking water. Apart from this water pollution affects plants and organisms living in these bodies of water. In almost all cases, the effect is damaging not only to individual species and population, but also to natural biological communities. In a nutshell, water pollution in rivers cause a havoc on ecological balance of the Earth. Over 97 per cent of all the water on Earth is salty and saline and most of the remaining three per cent is frozen in the polar icecaps. The atmosphere, rivers, lakes and underground store holds less than 1 per cent of all freshwater. This tiny amount has to support fresh water needs of the Earth's population. Fresh water is a precious resource and the increasing pollution of our rivers and lakes is a cause for alarm.
1. Causes of River Pollutions
(i) The Causes of River Pollutions are Untreated Sewage The discharge of untreated sewage in rivers is the single most important cause for pollution of rivers.
(ii) Agricultural Wastes If the large amount of fertilisers or farm waste drain into a river, the concentration of nitrate and phosphate in water increases considerably. Algae use these substances to grow and multiply rapidly turning the water green. The massive growth of algae called eutrophication, leads to pollution. When the algae dies, they are broken down by the action of bacteria which quickly multiply, using up all the oxygen in water which lead to the death of many animals.
(iii) Industrial Waste Chemical waste products of industrial processes are sometimes accidentally discharges into rivers. These substances may enter the water in such high concentrations that fish and other animals are killed immediately. Sometimes pollutants enter a food chain and accumulate until they reach toxic levels eventually killing birds, fish and mammals. These chemical causes many diseases to human beings like Cancer, Diarrhoea, etc.
(iv) Oil Pollution If oil enters a slow-moving river, it forms a rainbow coloured film over the entire surface preventing oxygen to enter the water. This cause death of many water organisms.
(v) Many human activities like throwing domestic and food wastes or throwing dead bodies in river also causes river pollution.
2.Ways to Overcome Water Pollution Ways to overcome water pollution are
(i) Various "action plans" have been started to clean rivers. Example the Ganga Action Plan, the Yamuna Action Plan, etc.
(ii) Emphasis is on going for technologies reducing the wastage of water and promoting recycling, improvement of water quality, etc.
(iii) Measures are being taken to divert raw sewage of effluents flown into the river to other locations for treatment and conversion into energy sources and chemicals.
(iv) The degradable and non-degradable wastes should be disposed in separate garbage bins for treatment.
67) Explain the 'National River Conservation Plan' (NRCP) in brief.
Answer: The central government sponsored scheme of National River Conservation Plan (NRCP) is being implemented by the central government jointly with the state governments on a cost-sharing basis. The pollution abatement works under NRCP presently covers polluted stretches of 39 major rivers and 185 towns spread over 20 states in the country. The activities of Ganga Action plan (GAP) Phase-1 initiated in 1985, were declaired closed on 31st March, 2000. The steering committee of the National River Conservation Authority reviewed the progress of the GAP and necessary correction on the basis of lessons learnt and experience gained from GAP Phase-I. These have been applied to the major polluted rivers of the country by the NRCP. The Ganga Action Plan (GAP) Phase-II has been merged with NRCP. A total of 215 schemes of pollution abatement have been sanctioned. So far, 69 schemes have been completed under this action plan. A million litres of sewage is targeted to be intercepted, diverted and treated.
68) What is an ox-bow lake?
Answer: A crescent shaped lake formed when a meander of a river or stream is cut-off from the main channel due to siltation.
69) Name five tributaries of the river Ganga.
Answer: Any five of the following Yamuna, Son, Ghaghara, Gandak, Kosi, Mahananda, Mahakali and Gomti.
70) What is a water divide?
Answer:Any elevated area, like a mountain or an upland, which divides two drainage basins.
71) Name five man-made lakes and five natural lakes in India.
Answer:Besides the lakes listed here, there are many others in both categories. Man-made Lakes
Natural Lakes Krishna Raja Sagar
Chilika Guru Gobind Sagar
Kolleru Gobind Ballabh Pant Sagar
Wular Nagarjuna Sagar
Sambhar Nizam Sagar
72) Name the river known as the 'Sorrow of West Bengal'. Why is it given this name?
Answer: This is the river Damodar, It is given this name because it is prone to floods every year, causing death and destruction due to overflowing of its banks.
73) What is the Indus Water Treaty?
Answer: The Indus Water Treaty is a water sharing treaty of the Indus basin between India and Pakistan. According to it, India can use only the waters of the Indus tributaries the Satluj, the Beas and the Ravi (comprising about 20 per cent of the water).
74) What is a braided stream?
Answer:A stream consisting of multiple small, shallow channels that divide and recombine numerous times, forming a pattern resembling the strands of a braid.
75) Name three famous waterfalls in India and the rivers on which they are situated.
Answer: Besides the waterfalls listed here, there are many others. The following are three famous waterfalls in India
Name of Waterfall
River on Which Situated
Sharavathi river (Shimoga, Karnataka)
Kyinshi river (West Khasi hills, Meghalaya)
Budhabalanga river (Mayurbhanj Odisha)
76) Name five rivers rising in the Western Ghats.
Answer:Godavari, Krishna, Kaveri, Tungabhadra, Ghatprabha and many others.
77) In the radial drainage pattern, why do streams flow in all directions from a central point?
Answer: The source of streams in a radial drainage pattern is an uplifted point like a mountain or volcano and the streams flow down by gravitation. The terrain of the mountain determines the path of these streams.
78) Name three major rivers of the subcontinent which originate beyond the Himalayas.
Answer: The three major rivers are the Indus, Saduj and the Brahmaputra.
79) Which river has the largest basin in India?
Answer: The largest basin in India is of the Ganga river with a drainage area of 862769 sq km.
80) Find out the name of the highest waterfall in India.
Answer: The highest waterfall in India is on the Varahi river in Shimoga district of Karnataka. The name of the waterfall is Kunchikal falls and its height is 455 metres (1493 ft).
81) What is meant by a water divide? Give an example.
Answer:Any elevated area such as a mountain or an upland that separates two drainage basins is called a water divide. An example are the Western Ghats.
82) Which is the largest river basin in India?
Answer: The Ganga Basin is the largest river basin in India.
83) Where do the rivers Indus and Ganga have their origin?
Answer: The river Indus rises in Tibet, near lake Mansarowar and the Ganga originates at the Gangotri glacier. Both of them have their origin in the Himalayas.
84) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
Answer: The two headstreams of the Ganga are the Bhagirathi and Alaknanda. They meet at Devaprayag in Uttarakhand to form the Ganga.
85) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Answer: In Tibet, the river Indus known as Tsangpo carries a smaller volume of water and less silt as it is a cold and dry area. In India, the river carries a large volume of water and considerable amount of silt because it passes through a region of high rainfall.
86) Which two peninsular rivers flow through a trough?
Answer:Narmada and Tapi are two Peninsular rivers which flow through a trough.
87) What you understand by the terms 'lagoon' and "estuary"?
Answer: Logoon : A shallow body of water, especially one separated from a sea by sandbars or coral reef is called lagoon. Estuary Estuary is widening channel of river where it nears the sea with a mixing of fresh water and salt water. It is a party enclosed,coastal body of brakish water where one or more rivers are discharging.
88) (a) Two features are shown on the outline map of India. Identify these features and write their names on the lines marked on the map. 1. A man-made lake in Sonbhadra district of Uttar Pradesh. 2.A river on which the Krishna Raja Sagar Dam has been built. (b) On the map, locate and label the following with appropriate symbols 1. A brackish water lake in the State of Odisha. 2. The longer river having trellis type drainage system and flowing through Madhya Pradesh and Gujarat.
Answer: (a) (i) Gobind Ballabh Pant Sagar (Riband dam is built on this) (ii) Kaveri river (b) 1. Chilika lake
2. Narmada river
89) (a) Two features are shown on the outline map of India. Identify these features and write their names on the lines marked on the map.
(i) A lake in Rajasthan from which salt is manufactured.
(ii)This river originates from the highlands of Chhattisgarh.
(b) On the map, locate and label the following with appropriate symbols
1. A salt water lake on the border between Andhra Pradesh and Tamil Nadu.
2. A river joining the Ganga from the South in Uttar Pradesh.
Answer: (a) (i) Sambhar lake (ii) Mahanadi river
(b) 1. Pulicat lake
2. Yamuna river
90) (a) Two features are shown on the outline map of India. Identify these features and write their names on the lines marked on the map. (a)The river flowing North of the Tapi and having its estuary in the Gulf of Khambat. (b) This river flows through three-countries. (b) On the map, locate and label the following with appropriate symbols 1. The river having the longest length in India. 2. This river flowing South of the Godavari has the largest river basin in South India.
Answer: (a) (i) Narmada (ii) Satluj
(b) 1. Ganga 2. Krishna
91) What does the term 'Drainage' mean?
Answer: The term 'drainage' describes the river system of an area.
92) What is a 'drainage basin'?
Answer:The area drained by a single river system is called a drainage basin.
93) Which part of the land is called 'water divide'?
Answer:Any elevated area, such as a mountain or an upland separates two drainage basins. Such an upland is known as a 'water divide'.
94) Into which two major groups are Indian rivers divided?
Answer: The Indian rivers are divided into two major groups
(i) The Himalayan Rivers,
(ii) The Peninsular Rivers.
95) Which rivers are called perennial?
Answer: Perennial rivers are the ones which have water throughout the year. These rivers receive water from rain as well as from melted snow from the lofty mountains.