class 9 - drainage

GEOGRAPHY Class IX Chapter 3 - DRAINAGE Q1. What do you mean by water divide? Give an example. Ans. Any elevated area such as mountains or an upland which separates two drainage basins are called water divide. For example Ambala is the water divide because it divides the Indus & the Ganga drainage system. Q2. Which is the largest river basin in India? Ans. Ganga is the largest river basin in India. Q3. Where do the rivers Indus & Ganga have their origin? Ans. The origin of Indus is in Tibet near Lake Mansarowar. The origin of Ganga is in Gangotri glacier with its two headstreams Alaknanda & Bhagirathi. Q4. Name the two headstreams of the Ganga. Where do they meet to form Ganga? Ans. The two headstreams of Ganga are Alaknanda & Bhagirathi which joins at Devaprayag at Uttrakhand to form Ganga. Q5. Why does the Brahmaputra in its Tibetan part less silt, despite a longer course? Ans.1. Its basin is made up of metamorphic rocks. 2. In Tibet the river carries a smaller volume of water, less silt, it is cold & dry area. Q6.Which two peninsular rivers flow through trough? Ans. Narmada & Tapi are two peninsular rivers flow through trough. Q7. State some economic benefits of rivers & lakes? Ans. Some economic benefits of rivers & lakes are: 1. Besides water Rivers carries sediments, dissolved water & less silt which are essential for agricultural & industrial development. 2. Rivers provides water for irrigation inland, navigation, many industries & domestic purposes. 3. Rivers water is also used for generating hypo electricity. 4. River water is also used for pisci culture & afforestation. 5. Plain surfaced valley of rivers is very fertile & ideal for agricultural operation. Q8. What is Indus water treaty? Ans. Indus water treaty is a treaty between India & Pakistan, according to which India can use only 20% of the total water carried by Indus river system. Haryana & Punjab used it for irrigation purposes. Q9.Discuss the significant differences between Himalayan river & Peninsular river. Himalayan river Peninsular river 1. They are perennial as they rise in the snow covered mountains. 1. They do not rise in snow covered mountains, their flow is dependent on rainfall so they run dry in summers. 2. As they flow in leveled northern plains, they are useful for irrigation & navigation. 2. As they flow on uneven rocky land, are not useful for irrigation & navigation. 3. They bring the fertile alluvium soil & deposit them in the indoor gangetic plains. 3. Since these rivers bring no alluvium so the depositional is quiet negligible. 4. Soil of the gangetic plains being porous. It absorbs lot of rain water which is used as grown water by digging wells, tube wells for irrigation, industrial & domestic purposes. 4. The soil of Deccan plateau is rocky, so it does not absorb water. Canals cannot be dug from them. But dams are build to store flood water. 5. The Himalayas rivers were have courses from their source to the sea & they perform intensive erosional activity. 5. The peninsular rivers have shorter & shallower courses as compare to Himalayan rivers. They also perform less erosional activity. Q10. Compare the east & west flowing rivers of peninsular plateau? West flowing East flowing 1. These rivers flow westward vary swiftly. The Narmada & Tapi flow through the rift valleys. 1. These rivers flow eastward. For example Mahanadi, Krishna & Kaveri. 2. Accept Narmada & Tapi these rivers have small courses. 2. These rivers have long courses, large basins & deep valleys. 3. These rivers do not form deltas. 3. Accept Mahanadi, most of the rivers have their own origin on western ghats. 4. The Narmada & Tapi form estuaries. 4. These rivers form deltas on their mouth. 5. These rivers fall into Arabian sea. 5. These rivers flow down into Bay of Bengal. Q11. Mention the main features of sunderban deltas. Ans. The main features of sunderban deltas are: I. The sunderban delta derived its name from the Sundari trees which well in marshland. II. It is the world’s largest & fastest growing delta. It is also the home of Royal Bengal tiger. Q12. Why South Indian Rivers are not navigable? Ans. South Indian rivers are not navigable because: I. The mountains from where south Indian rivers rise are not snow covered. These rivers are seasonal & dry up in summer. II. These rivers flow in a uneven rocky surface 7 have a steep gradient. III. Several dams have been constructed across the river channels which make them unfit for navigable Q13. What is river pollution? What are the major sources responsible for water pollution of the river? Ans. Untreated sewage of water & huge quantities of Industrial influences which are dumped into the water of rivers & make it polluted. This contamination is called water pollution, which makes water unfit for drinking purpose. SOURCES OF WATER POLLUTION Following are the major sources of water pollution of the rivers:  Untreated sewage of big towns & cities situated on the rivers (Delhi, Kanpur, Varanasi etc.) is developed into the river water.  Heavy load of chemical industrial influence from the big industries are developed into rivers.  Use of chemical fertilizers in the agriculture is on rise. During the rainy season the chemicals flow into the river water & make it contaminated.  Dead bodies of children, ashes of animals are thrown into the river which pollutes the river water.  Polythene bags thrown as waste after use also reach the rivers & choke them. Q14. Which is the largest, natural fresh water Lake in India? Ans. Wular lake is the largest, natural fresh water lake in India. Q15. Name the tributaries that joined Ganga from the north & from its right bank & from the south? Ans. Tributaries that join Ganga from the North – a. Ghaghara b. Gandak c. Kosi Tributaries that join Ganga from right bank – Yamuna Son Tributaries that join Ganga from its South – a. Chambal b. Betwa c. Son Q16. Name the two salt water takes of eastern coast. Ans. Chilika & Pulika are the two salt water lake of eastern coast. Q17. Mention some advantages of lakes? Ans. Some advantages of lakes are – 1) Lakes are of great value to human beings. They also helps to regulate flow of a river. 2) During heavy rainfall, it prevents flooding & during the dry season, it helps to maintain the even flow of water. 3) Lakes can also be used for developing hydel power. 4) They moderate the climatic of surrounding. They also maintain the aquatic ecosystem & enhance natural beauty. 5) They help to develop tourism & provide recreation.