Class 9 (Geography)
Chapter 3 (Drainage)
Notes
1. Drainage
is the term used to describe the river system within a particular area. It
refers to the network of rivers and streams that drain water from the land into
larger bodies of water such as lakes, seas, or oceans. A drainage basin,
also known as a river basin, encompasses the entire area drained by a
single river system. A water divide, typically an elevated landform like
a mountain or upland, separates adjacent drainage basins.
2. In
India, there are two main river systems based on their origin: the
Himalayan rivers and the Peninsular rivers. Himalayan rivers are
characterized by their perennial flow, as they are fed by both rainwater and
snowmelt throughout the year. These rivers create distinctive features such as
meanders and oxbow lakes along their courses. On the other hand, Peninsular
rivers are seasonal and primarily rely on rainfall, making them non-navigable
for most of the year. They originate in the Western Ghats and flow towards the
Bay of Bengal.
3. The Himalayan Rivers:
- The major Himalayan rivers include the
Indus, Ganga, and Brahmaputra.
- The Indus River system originates in
Tibet and flows through Ladakh into Pakistan before emptying into the
Arabian Sea.
- The Ganga River system, with its
headwaters in the Gangotri Glacier, is joined by various tributaries like
the Yamuna and Ghaghara before flowing into the Bay of Bengal via
Bangladesh.
- The Brahmaputra River system,
originating in Tibet, enters India through Arunachal Pradesh and flows
through Assam, forming riverine islands along its course.
4. The Peninsular Rivers:
- Major Peninsular rivers such as the
Godavari, Krishna, and Kaveri flow eastward into the Bay of Bengal, while
the Tapi and Narmada flow westward into the Arabian Sea.
- The Godavari, originating in
Maharashtra, has a vast basin covering parts of Maharashtra, Madhya
Pradesh, Orissa, and Andhra Pradesh.
- The Krishna and Kaveri rivers have their
origins in the Western Ghats and drain into the Bay of Bengal, with their
basins spanning multiple states.
5. India
is also home to various types of lakes, including permanent and non-permanent
ones, glacial lakes, oxbow lakes, lagoons, saltwater lakes, freshwater lakes,
and man-made lakes. These lakes serve multiple purposes such as regulating
river flow, hydroelectric power generation, and supporting aquatic ecosystems.
6. Rivers
play a crucial role in India's economy by providing water for agriculture,
facilitating transportation and navigation, generating hydroelectric power, and
supporting human settlements. However, pollution from untreated sewage,
industrial effluents, and agricultural runoff poses significant threats to
river ecosystems and water quality, necessitating efforts to mitigate pollution
and protect these vital resources.
7. Role
of rivers role in the economy of India. They are a vital source of water for
agriculture, which is the backbone of the country's economy. The fertile plains
along riverbanks support extensive agricultural activities, providing
livelihoods for millions of people.
Moreover, settlements and
cities have historically developed along the banks of rivers, facilitating
trade and commerce. Rivers serve as natural transportation routes, enabling the
movement of goods and people, which is essential for economic growth and
development.
Additionally, rivers are
utilized for hydropower generation, which contributes to India's energy needs.
Hydroelectric power plants harness the kinetic energy of flowing water to
produce electricity, reducing reliance on fossil fuels and promoting
sustainable energy sources.
8. River Pollution : However,
despite their economic significance, rivers face numerous challenges, particularly
regarding pollution. The quality of river water is adversely affected by
various factors, including untreated sewage, industrial effluents, and
agricultural runoff containing pesticides and fertilizers. This pollution not
only degrades water quality but also harms aquatic ecosystems and human health.
To address these issues,
various initiatives and action plans have been implemented to clean and restore
rivers across India. For example, the Narmada Bachao Movement advocates for the
protection of the Narmada River and its surrounding environment from large-scale
development projects that could potentially harm the ecosystem.
9. In conclusion,
rivers are indispensable resources that play a crucial role in India's economy.
They support agriculture, transportation, energy generation, and human
settlements. However, the sustainable management and conservation of rivers are
essential to ensure their continued contribution to India's economic prosperity
and environmental well-being.
Some Important Facts
1)
Different Patterns Formed by Streams:
a.
Dendritic,
b.
Trellis,
c.
Radial.
2)
Main Drainage Basins:
a.
The Indus Basin,
b.
The Ganga-Brahmaputra Basin.
3)
Drainage Pattern Where Hard and Soft
Rocks Exist Parallel:
a.
Trellis pattern.
4)
Definition of Drainage River Basin:
a.
The area drained by a single river system is
called a river basin or a drainage basin.
5)
Main Water Divide in Southern India:
a.
Western Ghats.
6)
Important Tributaries of Indus River:
a.
Zaskar and Nubra.
7)
Three Main Himalayan River Systems:
a.
The Indus River System,
b.
The Ganga River System,
c.
The Brahmaputra River System.
8)
Definition of a Gorge:
a.
A deep narrow opening formed by the river in
the upper course, e.g., the gorge formed by the river Indus.
9)
Origin of River Indus:
a.
In Tibet, near the Mansarovar lake.
10) Tributaries
of River Indus:
a.
The Zaskar, the Shyok, the Nubra, and the
Hunza.
11) Reasons
for Perennial Nature of Himalayan Rivers:
a.
Most originate from glaciers,
b.
Receive water from rainfall and glaciers.
12) City
Located on Water Divide Between Indus and Ganga River Systems:
a.
Ambala.
13) Indus
Water Treaty:
a.
Treaty signed between India and Pakistan
allowing India to use only 20% of the total water carried by the Indus river
system.
14) Plan
Launched to Reduce Pollution in River Ganga:
a.
The Ganga Action Plan.
15) Tributaries
of Ganga Rising in Nepal Himalayas:
a.
The Ghaghara and Kosi.
16) Northernmost
Point of Ganga Delta:
a.
Farakka in West Bengal.
17) Largest
River Basin in India:
a.
The Ganga Basin.
18) Length
of River Ganga:
a.
About 2500 km.
19) Headstreams
of River Ganga and Their Confluence:
a.
Bhagirathi and Alaknanda meet at Devprayag.
20) City
Where Ganga Enters Plains from Himalayas:
a.
Haridwar.
21) Tributaries
of River Ganga Entering Northern Plains from Nepal:
a.
Ghaghara, Gandak, and Kosi.
22) Main
Right Bank Tributaries of the Ganga:
a.
The Yamuna and the Son.
23) Brahmaputra
River in Tibet:
a.
Known as Tsangpo.
24) Origin
of River Brahmaputra:
a.
Arises in Tibet east of Mansarover lake.
25) Perennial
Rivers:
a.
Rivers that have water throughout the year.
26) Largest
Peninsular River and Origin:
a.
Godavari, originates from Nasik district of
Maharashtra.
27) Peninsular
Rivers Flowing Through Rift Valley:
a.
The Narmada and the Tapti.
28) Main
Watershed in Peninsular India:
a.
Formed by the Western Ghats.
29) Major
Rivers of Peninsular India:
a.
The Mahanadi, the Godavari, the Krishna, and
the Kaveri.
30) Small
River Basins of the Peninsular Region:
a.
The Pennar, and
b.
The Mahi.
31) Large
Rivers of India Flowing into the Arabian Sea:
a.
The Narmada and the Tapti.
32) Drainage
Pattern Made by Narmada River:
a.
Trellis.
33) Primary
Reason for Nonperennial Nature of Peninsular Rivers:
a.
Dependence on rainfall as the sole water
source.
34) Origin
of Narmada River:
a.
Near Amarkantak, in Madhya Pradesh.
35) Hills
Where the Tapi River Rises:
a.
Satpura ranges.
36) Origin
of the Tapti River:
a.
In the Betul district of Madhya Pradesh.
37) States
Through Which the Tapti River Flows:
a.
Madhya Pradesh, Gujarat, and Maharashtra.
38) State
With Largest Part of Godavari Basin:
a.
Maharashtra.
39) River
Known as Dakshin Ganga:
a.
Godavari.
40) Tributaries
of Godavari River:
a.
The Purna, the Wardha, the Pranhita, the
Manjra, the Wainganga, and the Pehganga.
41) Reasons
for Godavari River's Nickname:
a.
Due to its large size and extensive coverage.
42) Tributaries
of Krishna River:
a.
The Tungabhadra, the Koyna, the Ghatprabha,
the Musi, and the Bhima.
43) Source
of River Yamuna:
a.
Yamunotri glacier in the Himalayas.
44) City
at the Confluence of Yamuna and Ganga:
a.
Allahabad.
45) Punjab
Rivers Flowing into the Indus:
a.
The Sutlej, the Beas, the Ravi, the Chenab,
and the Jhelum.
46) Definition
of Canyon:
a.
A deep gorge with steep sides containing many
streams.
47) Location
of Most Freshwater Lakes:
a.
In the Himalayan region.
48) Largest
Natural Freshwater Lake of India:
a.
The Wular lake in Jammu and Kashmir.
49) Lake
Formed Due to Tectonic Activities:
a.
The Wular lake.
50) Saltwater
Lakes on Eastern Coast of India:
a.
The Chilika Lake,
b.
The Pulicat Lake.
51) Causes
of Increase in Demand for Water:
a.
Growing population,
b.
Urbanization.
52) Uses
of River Water:
a.
Farming, drinking, domestic, and industrial
uses.
53) Causes
of Ganga River Water Pollution:
a.
Disposal of raw sewage and industrial wastes,
b.
Reduction in water flow due to irrigation
abstraction through canals.
Important
Question Answers
Question 1: Define a river
system as a river combined with its tributaries. Then, elucidate two key
features of the River Indus:
Answer: A river system encompasses a river and its tributaries,
forming an interconnected network that drains water from a particular region.
One prominent example is the River Indus, which originates near the Mansarovar
lake in Tibet. With a remarkable total length of 2,900 kilometers, the River
Indus stands as one of the longest rivers globally. Its extensive reach
predominantly spans through Pakistan, where it serves as a vital resource for
agricultural activities, contributing significantly to the region's economy and
sustenance. Noteworthy tributaries such as the Nubra, Hunza, Sulley, Beas,
Ravi, Chenab, and Jhelum further enrich the River Indus's flow, augmenting its
significance in the landscape and livelihoods of the areas it traverses.
Question 2: Provide a brief
overview of the Brahmaputra river system.
Answer: The
Brahmaputra River system originates in Tibet, known as the Tsangpo River. It
flows eastward parallel to the Himalayas, making a significant U-turn around
the Namcha Barwa peak before entering India through Arunachal Pradesh. This
river is notorious for causing devastating floods in Assam and Bangladesh.
Interestingly, while the Brahmaputra receives less water and sediment in its
Tibetan segment, it carries a substantial volume of both when it reaches India.
Moreover, the river exhibits a braided channel for most of its length in Assam,
featuring several large islands within its course.
Question 3: Detail three
characteristics of the Ganga-Brahmaputra delta.
Answer: The
Ganga-Brahmaputra delta, also known as the Sundarbans Delta, derives its name
from the Sundari tree that thrives in marshland conditions. This expansive
delta, formed by the convergence of the Ganga and Brahmaputra rivers, is the
largest and fastest-growing delta globally. Notably, the Sundarbans Delta
serves as the habitat for the endangered Royal Bengal Tiger, showcasing rich
biodiversity within its ecosystem.
Question 4 What factors
contribute to the annual flooding of Himalayan rivers, and what benefits do
these floods bring?
Answer:
Himalayan rivers experience annual flooding due to factors such as snowmelt
from the lofty mountain peaks and heavy rainfall during the monsoon season.
These floods bring several advantages, such as enriching the soil in the
northern plains, making them highly conducive for agriculture. The fertile
lands resulting from these floods support the cultivation of various food and
cash crops, contributing significantly to agricultural productivity and
livelihoods in the region.
Question 5: What
advancements have been made under the Ganga Action Plan?
Answer: The
Ganga Action Plan has made significant strides in addressing pollution and
environmental degradation along the Ganga River. Sixty-nine schemes have been
successfully completed, yielding positive outcomes. Efforts include tree
plantation in badly eroded areas, repair of check dams in the river's upper
reaches, and the interception and diversion of major drains carrying sewage and
industrial wastes in cities like Varanasi, Kanpur, and Patna, effectively
reducing pollution levels. Additionally, the reappearance of turtles and
Gangetic dolphins, once disappeared for several years, in places like Varanasi,
signifies the plan's positive impact on river health and biodiversity.
Question 6.
Why are most of the Peninsular rivers draining into the Bay of Bengal? Give
reasons. Name the two rivers draining into the Arabian Sea.
Answer:
(i)
(a) The main water divide in Peninsular India is formed by the Western Ghats,
which runs from north to south close to the western coast..
(b) The Deccan Plateau is higher in the west and slopes gently eastwards.
Thus, most of the peninsular rivers such as Mahanadi, the Godavari, the Krishna
and the Kaveri flow eastwards and drain into the Bay of Bengal.
(ii) The river Narmada and river Tapi drain into the Arabian Sea.
Question 7: Which two rivers
of Peninsular India form estuaries, and in which states do these rivers drain
the water?
Answer: The
rivers Narmada and Tapi create estuaries as they flow into the sea. The Narmada
basin spans parts of Madhya Pradesh and Gujarat, while the Tapi basin covers
regions of Madhya Pradesh, Gujarat, and Maharashtra.
Question 8: What are the
reasons behind the seasonal nature of Peninsular rivers, and provide three
factors contributing to this phenomenon?
Answer:
Peninsular rivers exhibit a seasonal flow pattern primarily due to their
dependence on rainfall. Their shorter and shallower courses, compared to
Himalayan rivers, also contribute to this characteristic. Additionally, the
Peninsular rivers' limited number of short tributaries, which bring minimal
water to the main river, further exacerbate the reduction in water flow during
dry seasons.
Question 9: Detail the
primary characteristics of the Narmada Basin.
Answer: The
Narmada Basin features tributaries that join the mainstream at right angles,
with the river originating from the Amarkantak hills. It flows westward through
a rift valley formed by faulting, ultimately forming an estuary before meeting
the Gulf of Khambhat.
Question 10: Describe the
significant features of the Tapi Basin.
Answer: The
Tapi Basin is home to the second-largest peninsular river, originating in the
Satpura ranges of Madhya Pradesh. Similar to the Narmada, it flows through a
rift valley parallel to its counterpart but has a shorter length. The basin
encompasses parts of Madhya Pradesh, Gujarat, and Maharashtra.
Question 11: Outline three
notable features of the Krishna Basin.
Answer: The
Krishna River originates near Mahabaleshwar and spans approximately 1400
kilometers in length. It is joined by tributaries such as the Tungabhadra,
Koyana, Ghatprabha, Musi, and Bhima. The river's drainage basin is shared by
the states of Maharashtra, Karnataka, and Andhra Pradesh.
Question 12: What attributes
earn the Godavari River the nickname 'Dakshin Ganga'?
Answer: The
Godavari River, recognized as the largest peninsular river, boasts the largest
drainage basin among its counterparts, covering regions of Maharashtra, Madhya
Pradesh, Odisha, and Andhra Pradesh. Its extensive length and drainage area
have led to its alternate moniker, 'Dakshin Ganga.'
Question 13: Identify three
significant features of the Mahanadi Basin.
Answer: The
Mahanadi River originates in the highlands of Chhattisgarh and flows through
Odisha before emptying into the Bay of Bengal. With a length of about 860
kilometers, it traverses regions of Maharashtra, Chhattisgarh, Jharkhand, and
Odisha.
Question 14: Enumerate three
essential features of the Kaveri Basin.
Answer: The
Kaveri River originates in the Brahmagiri range of the Western Ghats,
terminating at the Bay of Bengal near Cuddalore, Tamil Nadu. Its primary
tributaries include the Amravati, Bhavani, Hemavati, and Kabini rivers. The
basin spans regions of Karnataka, Kerala, and Tamil Nadu.
Question 15: List three
similarities shared between Himalayan rivers and Peninsular rivers.
Answer:
Both Himalayan and Peninsular rivers exhibit delta formation and possess large
drainage basins. Additionally, these river systems are characterized by
numerous tributaries contributing to their water volume and silt content.
Question 16: What is the
significance of rivers as the lifelines of human civilization?
Answer:
Rivers are pivotal to human civilization as they have historically facilitated
the development of settlements and civilizations along their valleys. They
provide fertile lands for agriculture, support transportation networks for
trade and travel, and serve as a vital source of water for various human
activities.
Question 17: Predict the
consequences for humans in the absence of freshwater scarcity.
Answer: The
absence of freshwater scarcity would have profound implications for human
beings. Freshwater is essential for bodily functions, constituting a
significant portion of our body composition. Without access to freshwater,
humans would face challenges in waste removal, nutrient circulation, and
overall health maintenance. Additionally, the absence of freshwater would
impact ecosystems, affecting plant and animal life dependent on these water
sources for survival.
Question 18: Explain the
four drainage patterns.
Answer: There are four main
drainage patterns:
• Dendritic: This
pattern forms when river channels follow the slope of the terrain, resembling
the branching structure of a tree.
• Trellis: Tributaries join the main
river at right angles, often occurring where hard and soft rock layers run
parallel.
• Rectangular: Found in areas with
strongly-jointed rocky terrain, this pattern creates a grid-like network.
• Radial: Streams
flow outward from a central peak or dome-like structure, forming a radial
pattern.
Question 19: Provide five
examples supporting the statement "Rivers constitute the most useful
natural resources."
Answer:
Rivers are vital natural resources because: • They provide water essential for
the survival and growth of all organisms. • They facilitated early human
settlements, offering ideal conditions for settled life. • River processes
created fertile flood plains and deltas, supporting agriculture. • River water
is utilized for drinking, irrigation, and hydroelectric power generation. •
Rivers provide a food source through fishing and serve as natural waterways,
facilitating transportation. Additionally, river valleys have historically been
centers of civilization development.
Question 20: Describe the
key features of rivers originating from the Himalayas.
Answer:
Rivers originating from the Himalayas exhibit several distinctive features: •
Most Himalayan rivers are perennial, ensuring a continuous water supply. • They
have long courses from their source in the mountains to their endpoints. •
These rivers erode the landscape aggressively, carrying substantial sediment
loads. • They carve deep gorges through the mountains and often develop
well-defined deltas.
Question 21: List the main
characteristics of the Ganga river system.
Answer: The
Ganga river system is characterized by: • Two main headstreams, Alaknanda and
Bhagirathi, merging at Devprayag. • Entry into the plains at Haridwar, followed
by the convergence with numerous tributaries like Ghaghara, Gandak, and Kosi. •
The Yamuna and Son rivers are significant right bank tributaries. • In
Bangladesh, it becomes Padma and further downstream, Jamuna, before merging
with the Brahmaputra and Meghna rivers. • With a length exceeding 2500 km, the
Ganga has the largest basin among Indian rivers.
Question 22: Explain why the
Brahmaputra becomes a major river upon entering India.
Answer: The
Brahmaputra expands into a significant river in India due to several factors: •
In Tibet, where it originates, the Brahmaputra carries less water and sediment
due to the cold and dry climate. • Upon entering India from Arunachal Pradesh,
it receives contributions from various tributaries like the Dibang and Lohit,
increasing its volume. • The region it traverses in India experiences high
rainfall, causing the river to carry a substantial water flow and sediment
load. • Seasonal monsoon rains lead to frequent overflow, depositing large
amounts of sediment and raising the riverbed.
Question 23: Identify the
key features of the Ganga Action Plan.
Answer: The
main components of the Ganga Action Plan include: • Diverting sewage from
flowing directly into the river for treatment and energy conversion. •
Providing safe drinking water by constructing electric crematoriums and
separating bathing Ghats. • Diverting major drains carrying waste away from the
river in cities like Varanasi, Patna, and Kanpur, reducing pollution levels. •
Creating infrastructure capable of diverting and treating significant amounts
of domestic sewage daily. • Expanding the scope of the plan, which now covers
152 towns along 27 interstate rivers in 16 states, by integrating it with the
National River Conservation Plan.
Question 24: Differentiate
between a Delta and an Estuary.
Answer:
Delta |
Estuary |
Triangular deposits formed
by the river at its mouth constitute a delta. |
An estuary lacks deposits,
featuring a sharp edge at the river mouth. |
Deltas are typically found
in regions of low tide and coastal plains. |
Estuaries occur in areas
with high tides and rift valleys. |
Deltas create fertile
lands conducive to agriculture. |
Estuaries do not provide
fertile lands. |
Examples of rivers forming
deltas include the Ganga, Krishna, and Godavari. |
Estuaries are formed by
rivers like the Narmada and Tapi. |
Question 25: Describe the
differences between perennial and non-perennial rivers.
Answer:
Perennial Rivers |
Non-Perennial Rivers |
These rivers have water
throughout the year. |
Non-perennial rivers flow
only during the rainy season. |
Perennial rivers are
sustained by rainfall and melted snow. |
Non-perennial rivers
solely rely on rainfall for water supply. |
Most Himalayan rivers fall
under this category. |
The majority of Peninsular
rivers are non-perennial. |
Question 26: Explain the
'National River Conservation Plan' (NRCP) briefly.
Answer: The
National River Conservation Plan (NRCP) evolved from the Ganga Action Plan
(GAP) Phase-I, which concluded in 2000. The NRCP, integrating lessons learned
from GAP Phase-I, aims to address pollution in major rivers across India. Under
the NRCP, pollution abatement initiatives extend to 152 towns along 27
interstate rivers in 16 states. Notably, 57 towns are currently undergoing
pollution abatement efforts, with 215 schemes sanctioned and 69 completed. The
plan targets the interception, diversion, and treatment of one million liters
of sewage daily.
Question 27: Differentiate
between freshwater lakes and saltwater lakes, providing examples of each.
Answer:
Freshwater Lakes |
Saltwater Lakes |
Typically found in the
Himalayan region, often of glacial origin. |
Formed by spits and bars
in coastal areas or inland drainage regions. |
Examples include the Wular
Lake in Jammu and Kashmir and the Dal Lake. |
Notable examples are the
Chilika Lake and the Sambhar Lake in Rajasthan. |
Question 28: Why are rivers
important for the country’s economy?
Answer:
Rivers significantly contribute to a country's economy due to several reasons:
- Rivers provide essential water resources
for various human, agricultural, and industrial activities, fostering
economic development.
- Agriculture, which forms the backbone of
many economies, heavily relies on surface water from rivers for
irrigation.
- Rivers facilitate tourism, contributing
to economic growth through revenue generated from travel and related
services.
- Additionally, rivers serve as conduits
for cultural exchange and trade, promoting economic interactions between
regions and countries.
Question 29: Identify the
major factors responsible for river pollution and explain them.
Answer:
- High demand for water: Increasing demand
for water for domestic, municipal, industrial, and agricultural purposes
affects river quality by reducing its volume.
- Industrialization: Discharge of
untreated sewage and industrial effluents into rivers degrades water
quality and hampers self-cleansing abilities.
- Agricultural pollution: The use of
fertilizers and pesticides contaminates water bodies with heavy metals, posing
health risks through food consumption.
- Oil spills: Leakage of oil from tankers
pollutes oceans and water bodies, disrupting aquatic ecosystems.
Question 30: What are the
causes of water pollution, and how can it be controlled?
Answer: Water
pollution is caused by various factors:
- Industrial discharge and urban sewage
disposal into rivers.
- Overuse of fertilizers and pesticides in
agriculture.
- Oil spills from tankers contaminating
water bodies. Controlling water pollution involves:
- Preventing factories from discharging
waste into rivers.
- Treating waste before disposal into
water bodies.
- Implementing proper sewage management
practices.
- Regulating the use of fertilizers and
pesticides.
- Enforcing measures to prevent oil spills and leakage into water sources.
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