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Drainage NCERT Solutions - Geography for UPSC CSE

Q1. Choose the right answer from the four alternatives given below.

(i) In which of the following states is the Wular lake located?

Wular LakeWular Lake(a) Rajasthan
(b) Uttar Pradesh
(c) Punjab
(d) Jammu and Kashmir
(d) Jammu and Kashmir state.

Wular lake is the largest freshwater lake in India and is situated in the Bandipora district of Jammu and Kashmir. The lake is surrounded by beautiful mountains and serves as an important habitat for various species of migratory birds.

(ii) The river Narmada has its source at
(a) Satpura
(b) Brahmagiri
(c) Amarkantak
(d) Slopes of the Western Ghats
(c) Amarkantak

Amarkantak is a pilgrimage site and a hill station located at the meeting point of the Vindhya and Satpura mountain ranges. Narmada is one of the longest rivers in India, spanning a length of approximately 1,312 kilometers. It is often referred to as the "lifeline of Madhya Pradesh" and is considered sacred by Hindus.

(iii) Which one of the following lakes is a salt water lake?
(a) Sambhar
(b) Dal 
(c) Wular  
(d) Gobind Sagar
(a) Sambhar

Sambhar Lake, located in the state of Rajasthan, India, is a saltwater lake. It is the largest inland saltwater lake in India and serves as a major source of salt production in the country. 

(iv) Which one of the following is the longest river of the Peninsular India?
(a) Narmada
(b) Krishna
(c) Godavari
(d) Mahanadi
(c) Godavari

The Godavari River originates in the Western Ghats of Maharashtra and flows through the states of Maharashtra, Telangana, Andhra Pradesh, and eventually empties into the Bay of Bengal. The river stretches for about 1,465 kilometers (910 miles) in length, making it the longest river in Peninsular India. 

(v) Which one amongst the following rivers flows through a rift valley?
(a) Mahanadi
(b) Tungabhadra
(c) Krishna
(d) Tapi
(d) Tapi

A rift valley is a long, narrow valley that is formed by the sinking and separation of the Earth's crust. The Tapi River originates in the Betul district of Madhya Pradesh and flows through Maharashtra and Gujarat before draining into the Arabian Sea.

Q2. Answer the following questions briefly.

(i) What is meant by a water divide? Give an example.
Ans: A water divide is an elevated area, such as a mountain or an upland, that separates two drainage basins. For example, the water divide between the Indus and the Ganga river system is Ambala.

(ii) Which is the largest river basin in India?
Ans: The Ganga River basin is the largest one in India. The length of this basin is over 2,500 km.

(iii) Where do the rivers Indus and Ganga have their origin?
The Indus originates in Tibet, near Mansarovar Lake. The Ganga River originates at the Gangotri Glacier on the southern slopes of the Himalayas.

(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
Ans: The two headstreams of the Ganga are the Bhagirathi and the Alaknanda. They meet to form the Ganga at Devaprayag in Uttarakhand.

(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Ans: The Brahmaputra in its Tibetan part, carries a smaller volume of water and less silt as it is a cold and dry area.

(vi) Which two Peninsular rivers flow through trough?
Ans: The Narmada and the Tapi are the two peninsular rivers that flow through the trough.

(vii) State some economic benefits of rivers and lakes.
Ans: Economic benefits of rivers:

  • Rivers provide water, which is a basic natural resource for various human activities.
  • They are used for irrigation, navigation, and generation of hydroelectric power.
  • They have a moderating influence on the climate of the surroundings and maintain the aquatic ecosystem.

Economic benefits of lakes:

  • They help to regulate the flow of a river.
  • They prevent flooding at times of heavy rainfall and during the dry season, they help to maintain an even flow of water.
  • They also have a moderating influence on the surrounding climatic conditions and maintain the aquatic ecosystem.
  • They enhance natural beauty and recreational activities by encouraging tourism.
  • Lakes are also used for the generation of hydroelectricity.

Q3. 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
Ans: Natural Lakes
(a) Wular
(b) Dal
(c) Nainital
(d) Bhimtal
(f) Loktak
(g) Barapani
(h) Chilika
(i) Sambhar
(l) Pulicat
Lakes created by human beings
(e) Gobind Sagar
(j) Rana Pratap Sagar
(k) Nizam Sagar
(m) Nagarjuna Sagar
(n) Hirakund

Q4. Discuss the significant difference between the Himalayan and the Peninsular rivers.

The Himalayan RiversThe Peninsular Rivers
(i) They are perennial rivers. They get water from both the melted snow and heavy rainfall.(i) They are seasonal in nature. They depend on rainfall only.
(ii) They perform an immense erosional activity in the upper course.(ii) They do not perform any erosional activity in the upper course.
(iii) They have long courses from their source to the mouth.(iii) They have shorter and shallower courses.
(iv) They carry a large amount of silt and sand, which is renewed every year by annual floods. Therefore they are good for agriculture.(iv) These rivers do not carry much silt, there are no major plains. Fertile lands are only found in the small delta areas.
(v) The Ganga, the Indus, the Brahmaputra are major Himalayan rivers.(v) The Mahanadi, the Godavari, the Krishna, the Kaveri, the Narmada and the Tapi are major Peninsular rivers.

Q5. Compare the east-flowing and the west-flowing rivers of the Peninsular Plateau.

The East Flowing Rivers

The West Flowing Rivers

(i) The Mahanadi, the Godavari, the Krishna and the Kaveri are the east-flowing rivers of Peninsular India.

(i) The Narmada and the Tapi are the major west-flowing rivers of Peninsular India.

(ii) These rivers drain into the Bay of Bengal.

(ii) These rivers drain into the Arabian Sea.

(iii) These rivers form deltas on the east coast.

(iii) These rivers form estuaries on the west coast.

(iv) These rivers have a developed and large tributary system.

(iv) These rivers are devoid of any developed tributary system.


Q6. Why are rivers important for the country’s economy?
Ans: The rivers are important for the country’s economy due to the following reasons:

  • It is an important source of natural freshwater, which is required for the survival of most animals, including humans.
  • River water is used for various purposes like domestic, industrial, and agricultural purposes.
  • The presence of rivers boosts trade and commerce by helping in the easy transport of goods. They are also a potential source of energy.
  • River water is also used to run hydroelectric dams.
  • It is also used for navigation and transport, thus important for commercial activities.
  • It also provides fishing and great scenic and recreational value. Thus, serve as good tourist spots.

Map skills

Q. (i) On the outline map of India mark and label the following rivers: Ganga, Satluj, Damodar, Krishna, Narmada, Tapi, Mahanadi, and the Brahmaputra.
(ii) On an outline map of India mark and label the following lakes: Chilika, Sambhar, Wular, Pulicat, Kolleru 


Drainage NCERT Solutions | Geography for UPSC CSE

The document Drainage NCERT Solutions | Geography for UPSC CSE is a part of the UPSC Course Geography for UPSC CSE.
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FAQs on Drainage NCERT Solutions - Geography for UPSC CSE

1. What is drainage?
Ans. Drainage refers to the process of removing excess water from an area, typically through a system of pipes, ditches, or other drainage structures. It is important to prevent waterlogging and maintain the proper level of moisture for agricultural fields and urban areas.
2. How does drainage help in agriculture?
Ans. Drainage plays a crucial role in agriculture by removing excess water from the fields. It helps in maintaining the optimum moisture level in the soil, preventing waterlogging and its adverse effects on plant growth. Proper drainage also facilitates root development, nutrient absorption, and prevents soil erosion.
3. What are the different types of drainage systems?
Ans. There are various types of drainage systems used, including surface drainage, subsurface drainage, and vertical drainage. Surface drainage involves the removal of excess water from the surface through ditches or open channels. Subsurface drainage consists of installing pipes or drains below the ground to remove water from the soil. Vertical drainage involves the use of wells or boreholes to lower the water table.
4. What are the common problems associated with poor drainage?
Ans. Poor drainage can lead to several problems, such as waterlogging, soil erosion, reduced crop productivity, and the accumulation of salts and harmful chemicals in the soil. It can also result in the deterioration of infrastructure, such as roads and buildings, due to water damage. Additionally, poor drainage can create breeding grounds for mosquitoes and other pests.
5. How can drainage systems be maintained?
Ans. To maintain drainage systems, regular inspections and cleaning are necessary. This involves removing any blockages or debris that may hinder the flow of water. Additionally, proper maintenance of vegetation in and around drainage channels is essential to prevent clogging. In some cases, periodic repairs or upgrades may be required to ensure the effectiveness of the drainage system.
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