NCERT Solutions Class 11 Geography India Chapter 3 Drainage System

(i) Which one of the following rivers was known as the ‘Sorrow of Bengal’?

(d) The Damodar
Reason: It was called the Sorrow of Bengal due to frequent devastating floods. The construction of the Damodar Valley Corporation (DVC) has now tamed it.

(ii) Which one of the following rivers has the largest river basin in India?

(c) The Ganga
Reason: The Ganga basin covers the largest area within India (approx. 8.6 lakh sq. km). The Indus and Brahmaputra have larger total lengths but smaller basin areas within Indian territory.

(iii) Which one of the following rivers is not included in ‘Panchnad’?

(c) The Indus
Reason: ‘Panchnad’ refers to the five rivers of Punjab—Satluj, Beas, Ravi, Chenab, and Jhelum—that join together to drain into the Indus. The Indus is the main river they feed into.

(iv) Which one of the following rivers flows in a rift valley?

(b) The Narmada
Reason: The Narmada flows westwards through a rift valley between the Vindhya and Satpura ranges.

(v) Which one of the following is the place of confluence of the Alaknanda and the Bhagirathi?

(d) Devprayag
Reason: At Devprayag, the Bhagirathi meets the Alaknanda; hereafter, it is known as the Ganga. [Image of Panch Prayag map]

(i) River Basin and Watershed

River Basin	Watershed
It refers to the catchments of large rivers (e.g., Ganga Basin).	It refers to the catchments of small rivulets and rills.
It covers a vast area.	It covers a much smaller area.
Note: Geographically, “watershed” also denotes the boundary line separating two basins.	Often managed as a unit for development (Watershed Management).

(ii) Dendritic and Trellis Drainage Pattern

Dendritic Pattern	Trellis Pattern
Resembles the branches of a tree.	Resembles a rectangular grid.
Formed in areas of uniform rock structure where the river flows down the slope.	Formed where hard and soft rocks exist parallel to each other.
Example: The Ganga plains.	Example: Rivers in the old folded mountains of Singhbhum or the Appalachians.

(iii) Radial and Centripetal Drainage Pattern

Radial Pattern	Centripetal Pattern
Rivers flow outwards from a central peak or hill (like spokes of a wheel).	Rivers flow inwards towards a central depression or lake.
Source is a central highland (Dome).	Destination is a central lowland/basin.
Example: Amarkantak range (Narmada, Son flow out).	Example: Loktak Lake (Manipur) or Sambhar Lake.

(iv) Delta and Estuary

[Image of Delta vs Estuary diagram]

Delta	Estuary
A triangular depositional feature at the river mouth.	A semi-enclosed coastal body where river water meets seawater without forming deposits.
Formed by slow-moving rivers carrying heavy sediment load.	Formed by swift rivers or where tides/currents remove sediments.
Example: The Sunderbans (Ganga-Brahmaputra).	Example: The mouths of Narmada and Tapi.

(i) What are the socio-economic advantages of inter-linking of rivers in India?

Inter-linking can transfer water from surplus basins to water-deficit basins.
Advantages:

Irrigation: Provides water to drought-prone areas, boosting agriculture.
Flood Control: Reduces excess water in surplus rivers during monsoons.
Hydropower: Generates electricity through dams.
Navigation: Creates inland waterways for cheaper transport.

(ii) Write three characteristics of the Peninsular river.

Seasonal Flow: Most are rain-fed and depend on monsoons, often drying up in summer.
Fixed Course: They flow through hard rocky valleys and do not shift their courses (unlike Himalayan rivers).
Absence of Meanders: Due to hard rocks and faster flow in upper reaches, they rarely form meanders.

(i) What are the important characteristic features of north Indian rivers? How are these different from Peninsular rivers?

North Indian Rivers (Himalayan Rivers):

Perennial: They flow year-round as they are fed by both melting glaciers and monsoon rains.
Youthful Topography: In the mountains, they form deep V-shaped valleys, gorges, and waterfalls, engaging in intense erosion.
Shifting Courses: In the plains, they form meanders and oxbow lakes and frequently change courses (e.g., Kosi).

Difference from Peninsular Rivers:

Peninsular rivers are seasonal (rain-fed) vs Himalayan are perennial.
Peninsular rivers are old/mature with graded profiles vs Himalayan are young/active.
Peninsular rivers have hard rocky beds vs Himalayan rivers flow through soft alluvial soil in plains.

(ii) Journey from Haridwar to Siliguri along foothills: Name rivers and describe one.

Traveling east from Haridwar (Uttarakhand) to Siliguri (West Bengal) along the Himalayan foothills, one would cross the major left-bank tributaries of the Ganga.
Rivers encountered (West to East): Ramganga, Gomti, Ghaghara, Gandak, Kosi, and Mahananda.

Description of the Kosi:

Source: Tibeto-Nepal border (north of Mt. Everest).
Characteristics: It is an antecedent river known for frequently changing its course. It brings huge quantities of sediment from Nepal and deposits it in the plains, blocking its own channel and shifting path. This causes devastating floods, earning it the nickname “Sorrow of Bihar.”

Analysis of Appendix III

(i) Largest Catchment Area:
The Ganga river has the largest proportion of catchment area within the country.

(ii) Comparative Bar Diagram (Guidance):
To draw the graph:

X-Axis: Names of Rivers (Ganga, Godavari, Krishna, Yamuna, Narmada, Indus, Brahmaputra).
Y-Axis: Length in Km (Scale: 1 cm = 500 km).
Note: While Indus and Brahmaputra are longer in total, plot their lengths within India for a fair domestic comparison, or total length if specified. Generally, Ganga is the longest within India (2,525 km).