Q.1. What is a River System?
Ans. A river along with its tributaries is known as a River System or a Drainage system. Eg- Ganga River System, Indus River System etc.
Q.2. Define the term drainage.
Ans. The term drainage describes the river system of an area.
Q.3. What is a drainage basin?
Ans. The area drained by a single river system is called a drainage basin.
Q.4. What do you understand by the term Water Divide?
Ans. Any elevated area such as a mountain or an upland that separates two drainage basins is called a Water Divide. Ex. Ambala act as a water divide between Indus and Ganga River System.
Q.5. Define the following:
Ans. a. Drainage Pattern
The pattern formed by a river in a drainage basin depending upon the slope of land, rock structure and also climatic condition is referred to as Drainage Pattern.
b. Perennial Rivers
Perennial rivers are those which have water throughout the year. These rivers receive water from rain as well as from melted snow of the mountains. Eg-. Ganga, Indus, Brahmaputra.
c. Seasonal Rivers
Seasonal rivers are those which are dependent upon rainfall for their flow. During the dry season, even the large rivers have reduced the flow of water. Ex. Peninsular Rivers like Mahanadi, Godavari, Narmada etc.
Q.6. What are the two types of drainage systems found in India?
Ans. Himalayan and Peninsular river systems.
Q.7. Name the rivers that originate from Mansarovar Lake.
Ans. River Indus, Satluj and Brahmaputra
Q.8. Where the headwaters of Ganga meet at?
Ans. Bhagirathi and Alaknanda meet at Dev Prayag in Uttarakhand.
Q.9. Where river Ganga leaves behind the mountains and enter the plains?
Q.10. Which river flows in Tibet with the name Tsang Po?
Q.11. What is the source and mouth of the river?
Ans. The place from where the river originates is called as the Source of the river. The place where the river meets its end is known as the Mouth of the river.
Q.12.Apart from Narmada and Tapi, which are the other west flowing rivers?
Ans. Sabarmati, Mahi, Periyar, Bharathpuzha.
Q.13. Name the east flowing rivers of India apart from the major ones.
Ans. Damodar, Brahmani, Subarn rekha, Baitarni.
Q.14. Which peninsular rivers flow through a rift valley?
Ans. Narmada and Tapi
Q.15. Which rivers have the largest river basins in India and in Peninsular India?
Ans. In India: Ganga
In Peninsular India: Godavari
Q.16. What are the characteristics of river Yamuna?
Ans. a. River Yamuna originates from the Yamunotri glacier of the Himalayas.
b. It is the largest tributary of river Ganga.
c. The river moves parallel to Ganga for a long distance and finally meets with Ganga at Allahabad.
d. Many peninsular rivers join the Yamuna like Chambal, Betwa, Sindh etc.
Q.17. Explain the Indus Water Treaty.
Ans. a. The Indus Water Treaty was signed between India and Pakistan in 1960.
b. According to the regulations of this treaty India can use only 20% of the total water carried by Indus system.
c. This water is used for irrigation in the Punjab, Haryana and the southern and western parts of Rajasthan.
Q.18. What are the features of Sundarban Delta?
Ans. a. The delta formed by the rivers Ganga and Brahmaputra which is the largest delta of the world is known as Sundarban Delta.
b. The delta derived its name from the Sundari trees which grows well in this marshland.
c. It is the world’s fast growing delta.
d. It is also the home of Royal Bengal Tiger.
Q.19. Differentiate between the following:
A. Himalayan river system and Peninsular river system.
HIMALAYAN RIVER SYSTEM PENINSULAR RIVER SYSTEM
1. The Himalayan rivers originates from the Himalayas. The Peninsular rivers have their source in the peninsula of the country.
2. Most of the Himalayan rivers are perennial in nature, i.e., both rainfed and snowfed. Most of the peninsular rivers are seasonal in nature i.e. only rainfed.
3. Himalayan rivers have longer course and carry more sediments in them. Peninsular rivers have shorter course and carry less sediments in them.
4. These rivers are involved more in doing erosional and depositional activities and therefore, forms many land features like valleys, gorges, meanders, ox-bow lake, delta etc. These rivers are involved less in the erosional and depositional activities. Most of the rivers form only deltas.
5. These rivers have got comparatively larger drainage basin. The drainage basin formed by these rivers is less.
6. Ex. Indus river system, Brahmaputra river system, Ganga river system.
Ex. Mahanadi basin, Godavari basin, Tapi basin etc.
B. Distributaries and Tributaries
1. Distributaries are the small channels of rivers that separate themselves from the main river before entering into the sea. Tributaries are rivers or streams that join the main river.
2. Distributaries are formed in the lower course of the river. Tributaries join the main river in the upper and middle course of the river.
3. Distributaries decreases the volume of water and the sediments from the main river. Tributaries increases the volume of water and sediments deposition of the main river.
4. Ex. Hoogli is a distributary of river Ganga.
Ex. Yamuna is a tributary of Ganga.
C. Delta and Estuary
1. A delta is formed by the river when it is about to enter the sea by forming various distributaries. When the river directly enter the sea it forms an estuary. 2. It is roughly triangular in shape. It is a funnel shaped land feature.
3. The delta region is highly fertile because of the sediment deposition. The region near estuary is not very fertile.
4. Agriculture can be practiced here. Estuary regions are good for fishing activities.
5. Ex. River Ganga, Indus, Godavari, Mahanadi forms delta. Ex. Narmada and Tapi forms estuary.
D. East flowing rivers and West flowing rivers.
1. These rivers originate from or near to the Western Ghats and flows towards east. These rivers originate from east and flows towards western India.
2. These peninsular rivers have longer courses and more sediments deposition. These rivers have shorter courses and carry less sediment with them. 3. Most of the east flowing rivers forms delta while entering into the Bay of Bengal. Most of the rivers forms estuary while entering the Arabian sea.
4. Ex. Mahanadi, Godavari, Krishna, Kaveri.
Ex. Narmada and Tapi
Q.20. Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Ans. In Tibet, the river carries a smaller volume of water and less silt as it is a cold and a dry area. When the river enters India, the volume of water increases by the tributaries added into it, high rainfall and melting snow. Therefore, Brahmaputra in its Tibetan part have less silt, despite a longer course.
Q.21. Why river Godavari is often referred to as ‘Dakshin Ganga’?
Ans. Since river Ganga and Godavari are carrying similar characteristics, therefore, river Godavari is often referred to as ‘Dakshin Ganga’.
1. As river Ganga is the largest river of India with the largest drainage basin, similarly Godavari is the largest river of peninsular India with the largest drainage basin.
2. River Godavari and Ganga have the similar religious sentiments of the people attached to it.
Q.22. Explain the four drainage patterns.
Ans. DENDRITIC PATTERN
The dendritic pattern develops where the river channel follows the slope of the terrain. The stream along with its tributaries resembles the branches of a tree, thus the name dendritic. Ex. River Ganga along with its tributaries.
A river joined by its tributaries at approximately right angles, develop a trellis pattern. It is develop where hard and soft rocks are parallel to each-other. Ex. River Narmada along with its tributaries.
A rectangular pattern is developed on a strongly jointed rocky terrain.
The radial pattern develops when streams flow in different directions from a central peak or dome like structure. Ex. Rivers like Narmada and Tapi rising from the highlands of the peninsular plateau.
Q.24. Explain the different formations of lakes.
Ans. A. Oxbow lake
An oxbow lake is formed when the meandering river across a flood plain forms cut offs.
Spits and bars in the coastal areas formed by the depositional work of oceanic movement forms a lagoon.
Eg- Chilika lake (largest lake in India), Pulikat lake, Kolleru lake
C. Seasonal Lakes
Lakes in the region of inland drainage are sometimes seasonal which depends upon the rainfall. Eg-. Sambhar lake in Rajasthan which is a salt water lake.
D. Glacial Lake
These types of lakes are mostly found in Himalayan region. They are formed when glaciers dug out a basin which was later filled snow melt. Ex. Wular lake in Jammu & Kashmir which is the largest fresh water lake.
E. Artificial Lakes
Damming of rivers for the generation of hydel power has also led to the formation of lakes. Eg-. Guru Gobind Sagar on Bhakra Nangal Project.
Q.25. Why lakes are important for human beings?
Ans. a. Regulate the flow of river
Lakes help to regulate the flow of a river. During heavy rainfall, it prevents flooding and during the dry season, it helps to maintain an even flow of water.
b. Generation of Hydel Power
Damming of rivers is done in order to store the water for the generation of Hydro electricity. Ex. Hirakud dam on Mahanadi river.
c. Promote Tourism
Lakes are always an attraction for tourists for recreation. Lakes enhance the natural beauty of the adjoining area and hence, promote tourism. Ex. Wular lake, Dal Lake in Jammu & Kashmir.
d. Moderate Climate
Lakes also help in moderating the climate of the adjoining area that supports ecosystem within the lake and also outside the lake.
e. Source of rivers
Many lakes are also the major source for many rivers. Ex. Indus, Satluj, Brahmaputra have their source in the Mansarovar lake.
Q.26. What is the role of a river in building up of an economy?
Ans. a. Cradle of Civilization
River banks have attracted settlers from ancient times. All the major civilizations of the world were settled near to the river banks. Ex. Indus Valley Civilization, Nile Civilization etc. Even today, many important cities of the world are settled near to the river banks.
b. Basic Natural Resource
Rivers have been of fundamental importance throughout the human history. Water from the rivers is a basic natural resource, essential for various human activities.
c. Deposition of Sediments
The deposition of sediments done by the rivers makes the river banks highly good for cultivation, thus, promoting agriculture over there.
d. Other uses
Using rivers for irrigation, navigation, hydro-power generation is of special significance for a country.
Q.27. What are the main causes of increasing river pollution?
Ans. a. Industrial Effluents: A heavy load of untreated sewage and industrial effluents are emptied into the rivers. This affects the quality of water and also the self cleansing capacity of the river.
b. Urbanization: Modern trends of living consume more water. Moreover, the sewage problems in cities have further added to the problem of water pollution.
c. Domestic Use: The use of rivers and lakes done for domestic purposes like washing and bathing is adding to the problem of water pollution.