Drainage
NCERT Exercise Solution
Part 2
Question 11: Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Answer: Since Tibet is a cold and dry area, so Brahmaputra in this part carries less silt despite having a longer course.
Question 12: Which two Peninsular rivers flow through trough?
Answer: Narmada and Tapi
Question 13: State some economic benefits of rivers and lakes.
Answer: Lake can be used for generating hydroelectricity. A lake can be a good tourist attraction. Rivers have been the centre of human civilization since ancient times. Even today, many big cities are situated on the bank of a river. River water is used for irrigation, navigation, hydroelectricity, fisheries, etc.
Question 14: Below are given names of a few lakes of India. Group them under two categories – natural and created by human beings.
(a)Wular (b) Dal (c) Nainital (d) Bhimtal (e) Gobind Sagar (f) Loktak (g) Barapani (h) Chilika (i) Sambhar (j) Rana Pratap Sagar (k) Nizam Sagar (l) Pulicat (m) Nagarjuna Sagar (n) Hirakund
Answer: Natural Lakes: Wular, Dal, Bhimtal, Loktak, Barapani, Chilika, Sambhar, Pulicat
Man made Lakes: Gobind Sagar, Rana Pratap Sagar, Nizam Sagar, Nagarjuna Sagar, Hirakund
Question 15: Discuss the significant difference between the Himalayan and the Peninsular rivers.
Answer:
| Himalayan River | Peninsular River |
|---|---|
| Originate from the Himalayas | Originate in the Deccan Plateau |
| Most of them are very long | Most of them are shorter |
| Are perennial rivers | They dry up during summer months |
| Have much larger basins | Have smaller basins |
Question 16: Compare the east flowing and the west flowing rivers of the Peninsular plateau.
Answer: The east flowing rivers of the Peninsular part drain into Bay of Bengal and form deltas at their mouths. The west flowing rivers drain into the Arabian Sea and form estuaries. Most of the east flowing rivers are longer, compared to most of the west flowing rivers.
Question 17: Why are rivers important for the country’s economy?
Answer: Rivers are the major source of water for irrigation and hence are important for a country where farming is still the occupation of the largest portion of population. Many major rivers serve as important channels for transporting goods and people and thus play important role in the supply chain. Many multipurpose projects have been built on most of the major rivers in India. Rivers are important source of fish to a large population.
CROSSWORD Answers
- Nagarjuna Sagar is a river valley project. Name the river?
Answer: Krishna - The longest river of India.
Answer: Ganga - The river which originates from a place known as Beas Kund.
Answer: Beas - The river which rises in the Betul district of MP and flows westwards.
Answer: Tapi - The river which was known as the “Sorrow” of West Bengal.
Answer: Damodar - The river on which the reservoir for India Gandhi canal has been built.
Answer: Sutlej - The river whose source lies near Rohtang Pass.
Answer: Ravi - The longest river of Peninsular India?
Answer: Godavari - A tributary of Indus originating from Himachal Pradesh.
Answer: Chenab - The river flowing through fault, drains into the Arabian Sea.
Answer: Narmada - A river of south India, which receives rain water both in summer and winter.
Answer: Kaveri - A river which flows through Ladakh, Gilgit and Pakistan.
Answer: Indus - An important river of the Indian desert.
Answer: Luni - The river which joins Chenab in Pakistan.
Answer: Jhelum - A river which rises at Yamunotri glacier.
Answer: Yamuna