NCERT Solutions Class 9 Social Science Geography Contemporary India Chapter – 3 DRAINAGE
Q. 1. Choose the right answer from the four alternatives given below.
(i) In which of the following states is the Wular lake located?
(a) Rajasthan
(b) Uttar Pradesh
(c) Punjab
(d) Jammu and Kashmir
Answer:-
✅ Correct Answer: (d) Jammu and Kashmir
Explanation 🌊
Wular Lake, located in Jammu and Kashmir, is one of the largest freshwater lakes in India. It is situated in the Bandipora district and is fed by the Jhelum River.
📌 Other options explained:
- Rajasthan ❌ → Incorrect; known for Sambhar Lake, a saltwater lake.
- Uttar Pradesh ❌ → Incorrect; contains lakes like Ramsar Wetland (Surajpur Lake).
- Punjab ❌ → Incorrect; known for Harike Wetland, but Wular is not here.
(ii) The river Narmada has its source at
(a) Satpura
(b) Brahmagiri
(c) Amarkantak
(d) Slopes of the Western Ghats
Answer:-
✅ Correct Answer: (c) Amarkantak
Explanation 🌊
The Narmada River originates from Amarkantak, a plateau located in Madhya Pradesh. It is one of the major west-flowing rivers of India and is considered sacred. The river flows through Madhya Pradesh, Maharashtra, and Gujarat before draining into the Arabian Sea.
📌 Other options explained:
- Satpura ❌ → Incorrect; the Satpura Range lies nearby but is not the source of Narmada.
- Brahmagiri ❌ → Incorrect; the Brahmagiri hills in Karnataka are the source of the Godavari River.
- Slopes of the Western Ghats ❌ → Incorrect; rivers like Krishna and Kaveri originate from the Western Ghats, but not Narmada.
(iii) Which one of the following lakes is a salt water lake?
(a) Sambhar
(b) Dal
(c) Wular
(d) Gobind Sagar
Answer:-
✅ Correct Answer: (a) Sambhar Lake
Explanation 🌊
Sambhar Lake, located in Rajasthan, is India’s largest inland saltwater lake. It is famous for salt production and serves as an important wetland for migratory birds like flamingos.
📌 Other options explained:
- Dal Lake ❌ → Incorrect; located in Jammu & Kashmir, it is a freshwater lake, known for its houseboats. 🚣♂️
- Wular Lake ❌ → Incorrect; also in Jammu & Kashmir, it is one of the largest freshwater lakes in India. 🌿
- Gobind Sagar Lake ❌ → Incorrect; a reservoir created by the Bhakra Dam in Himachal Pradesh, holding freshwater. 💧
(iv) Which one of the following is the longest river of the Peninsular India?
(a) Narmada
(b) Krishna
(c) Godavari
(d) Mahanadi
Answer:-
✅ Correct Answer: (c) Godavari
Explanation 🌊
The Godavari River is the longest river in Peninsular India, stretching approximately 1,465 km. It originates from Trimbak (Maharashtra) and flows through Telangana, Andhra Pradesh, Chhattisgarh, and Odisha before emptying into the Bay of Bengal. Due to its vast basin and importance, it is often called “Dakshina Ganga” (Ganga of the South).
📌 Other options explained:
- Narmada River ❌ → Incorrect; though an important river, it flows westward, unlike most Peninsular rivers that flow eastward.
- Krishna River ❌ → Incorrect; shorter than the Godavari (Approx. 1,400 km), originates in Maharashtra.
- Mahanadi River ❌ → Incorrect; it is significant but much shorter, around 858 km, originating in Chhattisgarh.
(v) Which one amongst the following rivers flows through a rift valley?
(a) Mahanadi
(b) Tungabhadra
(c) Krishna
(d) Tapi
Answer:-
✅ Correct Answer: (d) Tapi River
Explanation 🌊
The Tapi River (also called Tapti) flows through a rift valley, which means it follows a deep depression formed due to tectonic forces. It originates from the Satpura range in Madhya Pradesh and flows westward into the Arabian Sea.
📌 Other options explained:
- Mahanadi River ❌ → Incorrect; it flows through Chhattisgarh and Odisha, but does not follow a rift valley.
- Tungabhadra River ❌ → Incorrect; originates from the Western Ghats and is a tributary of the Krishna River.
- Krishna River ❌ → Incorrect; flows through Maharashtra, Karnataka, Telangana, and Andhra Pradesh, but does not pass through a rift valley.
Q. 2. Answer the following questions briefly.
(i) What is meant by a water divide? Give an example.
(ii) Which is the largest river basin in India?
(iii) Where do the rivers Indus and Ganga have their origin?
(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
(vi) Which two Peninsular rivers flow through trough?
(vii) State some economic benefits of rivers and lakes.
Answer:-
(i) What is meant by a water divide? Give an example. 🌊
A water divide is a highland or ridge that separates the flow of water into different river systems. Rivers originating on either side of the divide flow in different directions.
🔹 Example: Western Ghats, which separates rivers flowing east into the Bay of Bengal and those flowing west into the Arabian Sea.
(ii) Which is the largest river basin in India? 🌏
The Ganga River Basin is the largest in India, covering approximately 8.6 lakh square km. It supports dense population, agriculture, and industries.
(iii) Where do the rivers Indus and Ganga have their origin? 🏞️
✔ Indus River – Originates from Tibetan Plateau near Lake Mansarovar.
✔ Ganga River – Originates from the Gangotri Glacier in Uttarakhand.
(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga? 🚰
✔ Bhagirathi and Alaknanda are the two headstreams of the Ganga.
✔ They meet at Devprayag (Uttarakhand) to form the Ganga River.
(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course? 🏔️
🔹 The Brahmaputra flows through Tibet in a cold and dry region, where there is less erosion. Due to this, the river carries less silt compared to its journey through India and Bangladesh, where erosion is much higher.
(vi) Which two Peninsular rivers flow through trough? ⛰️
✔ Narmada and Tapi Rivers flow through a rift valley (trough), created due to tectonic activity. These rivers are among the few west-flowing rivers in India.
(vii) State some economic benefits of rivers and lakes. 💰
✔ Irrigation – Essential for agriculture, providing water to crops 🌾
✔ Hydroelectric Power – Dams generate electricity for industries 🔋
✔ Fishing Industry – Supports livelihoods of millions 🐟
✔ Tourism & Transport – Boosts economy via boat rides, trade 🚢
✔ Drinking Water Supply – Important for cities and towns 🚰
📌 Exam Tips to Secure Full Marks 🎯✨
✔ Keep answers brief but detailed with proper keywords.
✔ Underline key terms (like Devprayag, Gangotri, Rift Valley).
✔ Use structured points for easy recall.
Q. 3. 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:-
✅ Grouping of Indian Lakes 🌊
Natural Lakes 🌿
These lakes were formed by natural processes such as tectonic movements, volcanic activity, and river action.
✔ Wular Lake – Largest freshwater lake in India (Jammu & Kashmir).
✔ Dal Lake – Famous for houseboats and tourism (Jammu & Kashmir).
✔ Nainital Lake – Tectonic lake surrounded by hills (Uttarakhand).
✔ Bhimtal Lake – Named after Bhima from Mahabharata (Uttarakhand).
✔ Loktak Lake – Known for floating islands (phumdis) (Manipur).
✔ Barapani (Umiam Lake) – A beautiful lake in Meghalaya.
✔ Chilika Lake – Largest brackish water lagoon in India (Odisha).
✔ Sambhar Lake – India’s largest inland saltwater lake (Rajasthan).
✔ Pulicat Lake – Second-largest brackish water lagoon (Andhra Pradesh & Tamil Nadu).
Lakes Created by Human Beings 🏗️
These lakes are man-made reservoirs, built for hydroelectric power, irrigation, and water storage.
✔ Gobind Sagar Lake – Created by Bhakra Dam (Himachal Pradesh).
✔ Rana Pratap Sagar Lake – Formed by Rana Pratap Sagar Dam (Rajasthan).
✔ Nizam Sagar Lake – Reservoir built on Manjira River (Telangana).
✔ Nagarjuna Sagar Lake – Created by Nagarjuna Sagar Dam (Telangana).
✔ Hirakud Lake – Formed by Hirakud Dam, India’s longest dam (Odisha).
Q. 4. Discuss the significant difference between the Himalayan and the Peninsular rivers.
Answer:-
✅ Differences Between Himalayan and Peninsular Rivers 🌊🌍
The Himalayan and Peninsular Rivers differ significantly in their origin, flow, and characteristics. These differences shape the geography, economy, and culture of India.
1️⃣ Origin & Course 🏔️
✔ Himalayan Rivers – Originate from glaciers and snow-capped mountains, ensuring year-round flow (e.g., Ganga, Indus, Brahmaputra).
✔ Peninsular Rivers – Originate from plateaus and hills, mostly fed by rainwater (e.g., Godavari, Krishna, Mahanadi).
2️⃣ Nature & Water Volume 💧
✔ Himalayan Rivers – Perennial rivers, meaning they carry water throughout the year, due to glaciers and rainfall.
✔ Peninsular Rivers – Seasonal rivers, their flow depends mostly on the monsoon rains.
3️⃣ Erosion & Landforms ⛰️
✔ Himalayan Rivers – Cause intense erosion, forming deep valleys, gorges, and fertile plains.
✔ Peninsular Rivers – Flow over hard rocks, creating broad valleys, waterfalls, and delta formations.
4️⃣ Drainage Patterns 🌊
✔ Himalayan Rivers – Form meandering patterns, as they flow through plains. They also create deltas at their mouths.
✔ Peninsular Rivers – Mostly straight, flowing through rocky terrain. Many end in estuaries instead of deltas.
5️⃣ Tributaries & Basin Area 🗺️
✔ Himalayan Rivers – Have many tributaries, forming large river basins (e.g., Ganga Basin, Indus Basin).
✔ Peninsular Rivers – Have fewer tributaries, with smaller drainage areas.
Q. 5. Compare the east flowing and the west flowing rivers of the Peninsular plateau.
Answer:-
✅ Comparison: East-Flowing vs. West-Flowing Rivers of the Peninsular Plateau 🌊🏞️
Peninsular India has two main types of rivers based on their direction of flow—east-flowing rivers draining into the Bay of Bengal and west-flowing rivers draining into the Arabian Sea.
1️⃣ Differences in Direction & Drainage Pattern
✔ East-Flowing Rivers – Flow toward the east, forming deltas before entering the Bay of Bengal (e.g., Godavari, Krishna, Mahanadi).
✔ West-Flowing Rivers – Flow toward the west, forming estuaries before entering the Arabian Sea (e.g., Narmada, Tapi, Mandovi).
2️⃣ Landforms & Erosion
✔ East-Flowing Rivers – Cause extensive erosion, leading to fertile floodplains and deltas.
✔ West-Flowing Rivers – Flow through rocky terrain, leading to deep valleys and gorges (e.g., Narmada Rift Valley).
3️⃣ Major Rivers & Length
✔ East-Flowing Rivers – Longer rivers with larger basins (e.g., Godavari is 1,465 km, longest in Peninsular India).
✔ West-Flowing Rivers – Shorter rivers with smaller drainage basins, except Narmada & Tapi which flow through rift valleys.
4️⃣ Tributaries & River Basins
✔ East-Flowing Rivers – Many tributaries contribute to large river basins (e.g., Ganga Basin, Godavari Basin).
✔ West-Flowing Rivers – Fewer tributaries, leading to smaller basins (except for the Indus River system).
Q. 6. Why are rivers important for the country’s economy?
Answer:-
✅ Importance of Rivers in the Country’s Economy 🌊💰
Rivers play a crucial role in supporting economic activities and ensuring the development of a country. They provide water resources, transportation, agriculture, and energy that drive the nation’s progress.
1️⃣ Agriculture & Irrigation 🌾
✔ Rivers supply water for irrigation, helping farmers grow crops like wheat, rice, sugarcane, and pulses.
✔ The Indus, Ganga, and Krishna basins are fertile regions that support food production.
2️⃣ Hydroelectric Power Generation 🔋
✔ Many rivers are dammed to produce hydroelectricity, a clean source of energy.
✔ Bhakra Nangal (Satluj), Hirakud (Mahanadi), and Sardar Sarovar (Narmada) dams provide power for industries & households.
3️⃣ Transport & Trade 🚢
✔ Rivers serve as natural waterways, reducing transportation costs.
✔ Major rivers like Ganga, Brahmaputra, and Godavari support inland navigation and trade.
4️⃣ Fishing & Livelihoods 🐟
✔ Rivers support fisheries, providing employment to millions.
✔ The Brahmaputra and Mahanadi river basins are rich in aquatic life.
5️⃣ Tourism & Cultural Significance 🏕️
✔ Rivers attract tourists, supporting local businesses.
✔ Many rivers have religious importance, boosting pilgrimage tourism (e.g., Ganga, Yamuna, Kaveri).