Class 9 NCERT Solutions Geography Chapter 3: Drainage
Drainage Exercise 23
Solution 1
Drainage Exercise 24
Solution 2
i)Any elevated area, such as a mountain or an upland, which separates two drainage basins is known as water divide.
Example: The Western Ghats form the main water divide in Peninsular India.
(ii) The Ganga, which is over 2,500 km long, forms the largest river basin in India.
(iii) The river Indus rises in Tibet, near Lake Mansarowar.
The Ganga originates at the Gangotri Glacier on the southern slopes of the Himalayas.
(iv) The two headstreams of the Ganga are Bhagirathi and Alaknanda. They meet to form the Ganga at Devaprayag in Uttarakhand.
(v) Since Tibet has a cold and dry climate, the Brahmaputra carries a smaller volume of water and less silt in this region.
(vi) Narmada and Tapi are the two peninsular rivers flowing through trough.
(vii) Some of the economic benefits of rivers and lakes are as follows:
- Rivers are of extreme importance in the human history. Many civilisations developed on the banks of rivers.
- River water is used for domestic and industrial consumption.
- River water is used for irrigation and navigation.
- River waters are used for the generation of electricity.
Solution 3
Solution 4
The Himalayan and the Peninsular rivers are different from each other in many ways.
The Himalayan rivers originate from the Himalayas. The peninsular rivers originate from the mountains and the hills that are located in or around the Peninsular Plateau. Significant difference between Himalayan and Peninsular rivers is that while the former are perennial rivers, the latter are seasonal. The Himalayan rivers have water throughout the year. They receive water from rain as well as from melted snow from the lofty mountains. On the other hand, the flow of Peninsular rivers is dependent upon rainfall. During the dry season, even the large rivers have reduced flow of water in their channels.
Since the Himalayan rivers have longer courses, erosion activity is more and the rivers carry down alluvial silt that they deposit in the plains. The peninsular rivers have shorter and swifter courses and so carry down less sediment. The drainage basins of the peninsular rivers are comparatively smaller in size.
Examples of the Himalayan rivers are the Ganga, Indus, Brahmaputra etc while the Godavari, Narmada, Tapi etc are examples of Peninsular rivers.
Solution 5
|
East Flowing rivers of the Peninsular India |
West flowing rivers of the Peninsular Plateau |
|
Mahanad. Godavari, Krishna and Kaveri are the major east flowing rivers. |
Narmada and Tapi are two main west flowing rivers. |
|
These rivers drain into Bay of Bengal. |
These rivers drain into the Arabian Sea. |
|
Since these rivers carry greater amount of sediment, they form deltas at their mouth. |
They form estuaries at their mouth as they carry less sediment. |
|
These rivers have many tributaries. |
These rivers have comparatively less number of tributaries. |
Solution 6
Rivers have been of fundamental importance throughout human history. Water from rivers is a basic natural resource, essential for various human activities.
Since the ancient times, settlers have been attracted to river banks. Ancient civilisations developed on the river banks and today many of these settlements have transformed into large cities.
The water from the rivers is used for various domestic, industrial and agricultural purposes.
The presence of rivers boosts trade and commerce by helping in the easy transportation of goods.
They are also a potential source of energy. The water from rivers is used for the generation of hydel electricity.
Regions having rivers are usually of great scenic and recreational value, and hence, serve as good tourist spots.
