Chapter 3 - Drainage
Question 1: Write the difference between Himalayan rivers and Peninsular rivers.
Answer:
• Himalayan rivers
→ Originate from Himalayas
→ Source is from glaciers and rain
→ Himalayan rivers are perennial. They have water throughout the year.
→ These rivers are long and deep.
→ They are very fertile.
→ Himalayan rivers perform high erosional activity and depositional work.
→ Example: Ganga, Brahmaputra, Indus
• Peninsular rivers
→ Originate from Gondwana land, Chhattisgarh Plateau, or Western Ghats
→ Source is from rain
→ Peninsular rivers are seasonal. They have less water throughout the year.
→ These rivers are short and shallow.
→ They are not that fertile.
→ Peninsular rivers perform high erosional activity and depositional work.
→ Example: Tapi, Narmada, Godavari
Question 2: Discuss the main features of Indus river system.
Answer: The main features of Indus river system are:
• The river Indus rises in Tibet, near Lake Mansarowar.
• It enters India in the Ladakh. It forms a picturesque gorge in this part.
• Several tributaries, the Zaskar, the Nubra, the Shyok and the Hunza, join it in the Kashmir region.
• The Indus flows through Baltistan and Gilgit and emerges from the mountains at Attock.
• The Satluj, the Beas, the Ravi, the Chenab and the Jhelum join together to enter the Indus near Mithankot in Pakistan. The Indus flows southwards eventually reaching the Arabian Sea, east of Karachi. The Indus plain has a very gentle slope.
• The Indus is one of the longest rivers of the world with the length of 2900 km.
• One third of the Indus basin is located in India and the rest is in Pakistan.
Question 3: Mention the main features of Godavari basin.
Answer:
• The Godavari is the largest Peninsular river. Its length is about 1500 km.
• It rises from the slopes of the Western Ghats in the Nasik district of Maharashtra. It drains into the Bay of Bengal.
• The basin covers parts of Maharashtra, Madhya Pradesh, Odisha and Andhra Pradesh.
• The Godavari is joined by a number of tributaries, such as the Purna, the Wardha, the Pranhita, the Manjra, the Wainganga and the Penganga.
• Because of its length and the area it covers, it is also known as the Dakshin Ganga.
Question 4: Explain the role of rivers in the economy.
Answer:
• Rivers have been of fundamental importance throughout the human history. Water from rivers is a basic natural resource, essential for various human activities.
• Riverbanks have attracted settlers from ancient times. These settlements have now become big cities.
• Using rivers for irrigation, navigation, hydro-power generation is of special significance where agriculture is the major source of livelihood of the majority of its population.
Question 5: “Lakes are of great value to human beings.” Explain.
Answer: Lakes are of great value to human beings.
• A lake helps to regulate the flow of a river.
• During heavy rains, it prevents flooding and during the dry season, it helps to maintain an even flow of water.
• Lakes can also be used for developing hydel power.
• They moderate the climate of the surroundings; maintain the aquatic ecosystem, enhance natural beauty, help develop tourism and provide recreation.
Question 6: Compare the East flowing and West flowing rivers of the Peninsular Plateau.
Answer:
• East flowing rivers
→ Drain in Bay of Bengal
→ Originate from Western Ghats and flow towards East
→ Carry large amounts of water
→ Form delta at the mouth of the rivers
→ Example: Krishna, Godavari
• West flowing rivers
→ Drain in Arabian Sea
→ Originate in Central region of India and flow towards West
→ Carry less amount of water as compared to East flowing rivers
→ Forms estuaries at the mouth of the rivers
→ Example: Narmada, Tapi
Question 7: Define the following terms
a) Estuary
b) Drainage basin
c) Water divide
d) River system
Answer:
a) Estuary: The part of the river where it joins the sea and where the fresh water and sea water are mixed is known as estuary. It is partially enclosed coastal water body where the fresh water from the rivers and streams mixes with saltwater in ocean.
b) Drainage basin: The area drained by a single river system is called a drainage basin.
c) Water divide: It is an elevated area, such as a mountain or an upland, that separates two drainage basin is called water divide.
d) River system: A river along with its tributaries may be called a river system.
Question 8: Explain the Ganga river system.
Answer:
• The headwaters of the Ganga, called the ‘Bhagirathi’ is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttarakhand. At Haridwar, the Ganga emerges from the mountains on to the plains.
• Tributaries that join Ganga are the Yamuna, the Ghaghara, the Gandak and the Kosi. The river Yamuna rises from the Yamunotri Glacier in the Himalayas and as a right bank tributary, it meets the Ganga at Allahabad. The Ghaghara, the Gandak and the Kosi rise in the Nepal Himalaya.
• The tributaries, which come from the peninsular uplands, are the Chambal, the Betwa and the Son.
• The Ganga flows eastwards till Farakka in West Bengal. This is the northernmost point of the Ganga delta.
• The Bhagirathi-Hooghly flows southwards through the deltaic plains to the Bay of Bengal. The mainstream, flows southwards into Bangladesh and is joined by the Brahmaputra.
• Further downstream, it is known as the Meghna. This mighty river, with waters from the Ganga and the Brahmaputra, flows into the Bay of Bengal. The delta formed by these rivers is known as the Sundarban Delta.
• The length of Ganga is about 2500 km. Ambala is located on the water divide between the Indus and the Ganga river system.
Question 9: Explain the Brahmaputra river system.
Answer:
• The Brahmaputra rises in Tibet east of Mansarowar Lake very close to the sources of the Indus and the Satluj.
• It flows eastwards parallel to the Himalayas. On reaching the Namcha Barwa, it takes a ‘U’ turn and enters India i0n Arunachal Pradesh through a gorge. It is also known as the Dihang and it is joined by the Dibang, the Lohit, and many other tributaries to form the Brahmaputra in Assam.
• In Tibet, the river carries a smaller volume of water and less silt as it is a cold and a dry area.
• In India, it passes through a region of high rainfall. Here the river carries a large volume of water and considerable amount of silt.
• Brahmaputra is known as the Tsang Po in Tibet and Jamuna in Bangladesh.
• The Brahmaputra forms the world’s largest riverine island, Majuli.
Question 10: Describe the Narmada Basin.
Answer:
• The Narmada rises in the Amarkantak hills in Madhya Pradesh.
• It flows towards the west in a rift valley formed due to faulting.
• On its way to the sea, the Narmada creates many picturesque locations. The ‘Marble rocks’, near Jabalpur, where the Narmada flows through a deep gorge, and the ‘Dhuadhar falls, where the river plunges over steep rocks.
• All tributaries of the Narmada are very short and most of these join the main stream at right angles.
• The Narmada basin covers parts of Madhya Pradesh and Gujarat.
Question 11: Describe the Tapi basin.
Answer:
• The Tapi rises in the Satpura ranges, in the Betul district of Madhya Pradesh.
• It also flows in a rift valley parallel to the Narmada but it is much shorter in length.
• Its basin covers parts of Madhya Pradesh, Gujarat and Maharashtra.
• The coastal plains between Western Ghats and the Arabian Sea are very narrow. Hence, the coastal rivers are short.
• The main west flowing rivers are Sabarmati, Mahi, Bharathpuzha and Periyar.
Question 12: Write short notes on the Mahanadi basin.
Answer:
• The Mahanadi rises in the highlands of Chhattisgarh.
• It flows through Odisha to reach the Bay of Bengal.
• The length of the river is about 860 km.
• Its drainage basin is shared by Maharashtra, Chhattisgarh, Jharkhand, and Odisha.
Question 13: Write short notes on the Krishna basin.
Answer:
• It rises from a spring near Mahabaleshwar, the Krishna flows for about 1400 km and reaches the Bay of Bengal.
• The Tungabhadra, the Koyana, the Ghatprabha, the Musi and the Bhima are some of its tributaries.
• Its drainage basin is shared by Maharasthra, Karnataka and Andhra Pradesh.
Question 14: Explain the Kaveri basin.
Answer:
• The Kaveri rises in the Brahmagri range of the Western Ghats and it reaches the Bay of Bengal in south of Cuddalore in Tamil Nadu.
• The total length of the river is about 760 km.
• Its main tributaries are Amravati, Bhavani, Hemavati and Kabini.
• Its basin drains parts of Karnataka, Kerala and Tamil Nadu.
• It makes the second biggest waterfall in India, Shivasamudram Falls or Jog Falls.
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