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                                 CLASS – IX

                                 CHAPTER -3


                           (summative assessment 1)

Q.1. What is a River System?

Ans. A river along with its tributaries is known as a River System or a Drainage system. Ex.
Ganga River System, Indus River System etc.

Q.2. Define the term drainage.

Ans. The term drainage describes the river system of an area.

Q.3. What is a drainage basin?

Ans. The area drained by a single river system is called a drainage basin.

Q.4. What do you understand by the term Water Divide?

Ans. Any elevated area such as a mountain or an upland that separates two drainage basins is
called a Water Divide. Ex. Ambala act as a water divide between Indus and Ganga River System.

Q.5. Define the following:

Ans. a. Drainage Pattern

        The pattern formed by a river in a drainage basin depending upon the slope of land, rock
structure and also climatic condition is referred to as Drainage Pattern.

       b. Perennial Rivers

        Perennial rivers are those which have water throughout the year. These rivers receive
water from rain as well as from melted snow of the mountains. Ex. Ganga, Indus, Brahamaputra.

       c. Seasonal Rivers
       Seasonal rivers are those which are dependent upon rainfall for their flow. During the dry
season, even the large rivers have reduced the flow of water. Ex. Peninsular Rivers like
Mahanadi, Godavari, Narmada etc.

Q.6. What are the two types of drainage systems found in India?

Ans. Himalayan and Peninsular river systems.

Q.7. Name the rivers that originate from Mansarovar Lake.

Ans. River Indus, Satluj and Brahmaputra

Q.8. Where the headwaters of Ganga meet at?

Ans. Bhagirathi and Alaknanda meet at Dev Prayag in Uttarakhand.

Q.9. Where river Ganga leaves behind the mountains and enter the plains?

Ans. Haridwar

Q.10. Which river flows in Tibet with the name Tsang Po?

Ans. Brahamaputra

Q.11. What is the source and mouth of the river?

Ans. The place from where the river originates is called as the Source of the river.

       The place where the river meets its end is known as the Mouth of the river.

Q.12.Apart from Narmada and Tapi, which are the other west flowing rivers?

Ans. Sabarmati, Mahi, Periyar, Bharathpuzha.

Q.13. Name the east flowing rivers of India apart from the major ones.

Ans. Damodar, Brahmani, Subarn rekha, Baitarni.

Q.14. Which peninsular rivers flow through a rift valley?

Ans. Narmada and Tapi

Q.15. Which rivers have the largest river basins in India and in Peninsular India?

Ans. In India: Ganga

       In Peninsular India: Godavari

Q.16. What are the characteristics of river Yamuna?
 Ans. a. River Yamuna originates from the Yamunotri glacier of the Himalayas.

 b. It is the largest tributary of river Ganga.

 c. The river moves parallel to Ganga for a long distance and finally meets with Ganga at

 d. Many peninsular rivers join the Yamuna like Chambal, Betwa, Sind etc.

 Q.17. Explain the Indus Water Treaty.

 Ans. a. The Indus Water Treaty was sighned between India and Pakistan in 1960.

 b. According to the regulations of this treaty India can use only 20% of the total water carried by
 Indus system.

 c. This water is used for irrigation in the Punjab, Haryana and the southern and western parts of

 Q.18. What are the features of Sundarban Delta?

 Ans. a. The delta formed by the rivers Ganga and Brahmaputra which is the largest delta of the
 world is known as Sundarban Delta.

 b. The delta derived its name from the Sundari trees which grows well in this marshland.

 c. It is the world’s fast growing delta.

 d. It is also the home of Royal Bengal Tiger.

 Q.19. Differentiate between the following:

 Ans. A. Himalayan river system and Peninsular river system.

  1. The Himalayan rivers originates from          The Peninsular rivers have their source in the
     the Himalayas.                                peninsula of the country.
  2. Most of the Himalayan rivers are              Most of the peninsular rivers are seasonal in
     perennial in nature, i.e., both rainfed       nature i.e. only rainfed.
     and snowfed.
  3. Himalayan rivers have longer course           Peninsular rivers have shorter course and carry
     and carry more sediments in them.             less sediments in them.
  4. These rivers are involved more in doing       These rivers are involved less in the erosional
     erosional and depositional activities         and depositional activities. Most of the rivers
     and therefore, forms many land features       form only deltas.
     like valleys, gorges, meanders, ox-bow
     lake, delta etc.
  5. These rivers have got comparatively           The drainage basin formed by these rivers is
     larger drainage basin.                        less.
  6. Ex. Indus river system, Brahmaputra           Ex. Mahanadi basin, Godavari basin, Tapi
     river system, Ganga river system.             basin etc.

B. Distributaries and Tributaries

      DISTRIBUTARIES                                      TRIBUTARIES
  1. Distributaries are the small channels of      Tributaries are rivers or streams that join the
     rivers that separate themselves from the      main river.
     main river before entering into the sea.
  2. Distributaries are formed in the lower        Tributaries join the main river in the upper and
     course of the river.                          middle course of the river.
  3. Distributaries decreases the volume of        Tributaries increases the volume of water and
     water and the sediments from the main         sediments deposition of the main river.
  4. Ex. Hoogli is a distributary of river         Ex. Yamuna is a tributary of Ganga.

C. Delta and Estuary

           DELTA                                             ESTUARY
  1.   A delta is formed by the river when it is   When the river directly enter the sea it forms
       about to enter the sea by forming           an estuary.
       various distributaries.
  2.   It is roughly triangular in shape.          It is a funnel shaped land feature.
  3.   The delta region is highly fertile          The region near estuary is not very fertile.
       because of the sediment deposition.
  4.   Agriculture can be practiced here.          Estuary regions are good for fishing activites.
  5.   Ex. River Ganga, Indus, Godavari,           Ex. Narmada and Tapi forms estuary.
       Mahanadi forms delta.

D. East flowing rivers and West flowing rivers.

    EAST FLOWING RIVERS                                 WEST FLOWING RIVERS
  1. These rivers originate from or near to        These rivers originate from east and flows
     the Western Ghats and flows towards           towards western India.
  2. These peninsular rivers have longer           These rivers have shorter courses and carry
     courses and more sediments deposition.        less sediment with them.
  3. Most of the east flowing rivers forms         Most of the rivers forms estuary while entering
     delta while entering into the Bay of          the Arabian sea.
  4. Ex. Mahanadi, Godavari, Krishna,              Ex. Narmada and Tapi

Q.20. Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?

Ans. In Tibet, the river carries a smaller volume of water and less silt as it is a cold and a dry

When the river enters India, the volume of water increases by the tributaries added into it, high
rainfall and melting snow.

Therefore, Brahmaputra in its Tibetan part have less silt, despite a longer course.

Q.21. Why river Godavari is often referred to as ‘Dakshin Ganga’?

Ans. Since river Ganga and Godavari are carrying similar characteristics, therefore, river
Godavari is often referred to as ‘Dakshin Ganga’.

   1. As river Ganga is the largest river of India with the largest drainage basin, similarly
      Godavari is the largest river of peninsular India with the largest drainage basin.

   2. River Godavari and Ganga have the similar religious sentiments of the people attached to

Q.22. Explain the four drainage patterns.


                The dendritic pattern develops where the river channel follows the slope of the
terrain. The stream along with its tributaries resembles the branches of a tree, thus the name
dendritic. Ex. River Ganga along with its tributaries.


                 A river joined by its tributaries at approximately right angles, develop a trellis
pattern. It is develop where hard and soft rocks are parallel to each-other. Ex. River Narmada
along with its tributaries.


               A rectangular pattern is developed on a strongly jointed rocky terrain.

                The radial pattern develops when streams flow in different directions from a
 central peak or dome like structure. Ex. Rivers like Narmada and Tapi rising from the highlands
 of the peninsular plateau.

 Q.23. Study the information regarding the major river systems of India with the help of the
 following table:

RIVER          SOURCE             MOUTH          LENGTH    TRIBUTARIES             COURSE
Indus river    Near               Forms a        2900km    *In Jammu and           From Tibet, river
system         Mansarovar         delta to the             Kashmir – Shyok,        flows towards west
               lake, in Tibet     east of                  Hunza, Zaskar and       and enters India
                                  Karachi in               Nubra.                  through Ladakh
                                  Pakistan                 *Satluj, Beas, Ravi,    district (J&K). In
                                                           Chenab and Jhelum       Kashmir valley,
                                                           meets Indus near        river flows through
                                                           Mithankot in            Baltistan and Gilgit
                                                           Pakistan                and emerges at
                                                                                   Attock mountain,
                                                                                   Enters Pakistan and
                                                                                   flows southwards
                                                                                   towards Arabian sea.
Ganga river    Headwaters-        Meets with Over          *Left bank              From Dev Prayag
system         Bhagirathi from    Brahmaput 2500km.        tributaries:            the river flows in the
               Gangotri glacier   ra in                    Ghaghara, Gandak        rugged mountainous
               meets with         Banglades                and Kosi rising from    region and enter the
               Alaknanda at       h and                    Nepal Himalayas.        plains at Haridwar.
               Dev Prayag in      forms the                *Right bank             Crossing the states
               Uttarakhand to     largest                  tributaries:            like Uttarakhand,
               form river         delta of                 **Yamuna is the         Uttar Pradesh, Bihar
               Ganga.             the world                largest tributary.      and West Bengal the
                                  known as                 **Son, a peninsular     river enters
                                  Sundarban                river is also a right   Bangladesh. At
                                  Delta (Bay               bank tributary.         Farakka in West
                                  of Bengal)               **Sind, Chambal,        Bengal, The river
                                                           Betwa are the           divides itself into
                                                           tributaries of          distributaries like
                                                           Yamuna and              Hoogli. From here,
                                                           therefore, becomes a    the river moves
                                                           part of Ganga river     southward to form
                                                           system.                 the delta towards
                                                                                   Bay of Bengal.
Brahamaputra   East of            Meets with Over          Dibang, Lohit,          It flows eastward
River System   Mansarovar lake    Ganga in   2900km        Kenula, etc.            parallel to
               in Tibet           Banglades                                        Himalayas in the
                                  h and                                            Tibet. On reaching
                                  forms the                                        Namcha Barwa, it
                                  largest                                          takes a ‘U’ turn and
                                  delta of                                         enters India through
                                  the world                                        a gorge in Arunachal
                                  known as                                         Pradesh. The river
                                    Sundarban                                           moves forward
                                    Delta (Bay                                          towards Assam and
                                    of Bengal                                           enters Bangladesh to
                                                                                        form the delta with
Narmada         From                Forms an                   All the tributaries of   The river flows
basin           Amarkantak          estuary                    Narmada are very         towards the west in a
                hills in Madhya     while                      short and join the       rift valley. Near
                Pradesh             entering                   main stream at right     Jabalpur, the river
                                    into the                   angle.                   flows through a deep
                                    Arabian                                             gorge. Narmada
                                    sea.                                                basin covers parts of
                                                                                        Madhya Pradesh and
Tapi basin      Rises in Satpura    Forms an      Shorter                               It also flows in a rift
                range, Betul        estuary       than                                  valley, parallel to
                district of         while         Narmada                               Narmada. Its basin
                Meghalaya.          entering                                            covers parts Madhya
                                    into the                                            Pradesh,
                                    Arabian                                             Maharashtra, and
                                    sea.                                                Gujarat.
Mahanadi        Rises in the        Forms a       About                                 The drainage basin
Basin           highlands of        delta while   860km                                 of river Mahanadi is
                Chattisgarh.        entering                                            shared by
                                    into Bay                                            Maharashtra,
                                    of Bengal.                                          Chattisgarh,
                                                                                        Jharkhand and
Godavari        Rises from          Forms a       1500km       Purna, Wardha,           Godavari has the
Basin           slopes of the       delta while   (largest     Penganga,                largest drainage
                Western Ghats       entering      peninsular   Wainganga etc.           basin among the
                in Nasik district   into Bay      river)                                peninsular rivers. It
                of Maharashtra.     of Bengal                                           cover Maharashtra
                                                                                        (50%), Madhya
                                                                                        Pradesh, Orissa, and
                                                                                        Andhra Pradesh.
Krishna Basin   Rises from a        Forms a       About        Tungabhadra,             The drainage basin
                spring near         delta while   1400km       Bhima, Musi,             of river Krishna is
                Mahabaleashwar      entering                   Koyana etc.              shared by
                in Maharashtra      into Bay                                            Maharashtra,
                                    of Bengal                                           Karnataka, and
                                                                                        Andhra Pradesh.
Kaveri Basin    Rises in            Forms a       About        Amravati, Bhavani,       Its basin drains parts
                Brahmagri range     delta while   760km        Hemavati, Kabini.        of Karnataka,
                of Western          entering                                            Kerela, and Tamil
                Ghats.              into Bay                                            Nadu.
                                    of Bengal
                                    to the
                                    south of
Q.24. Explain the different formations of lakes.

Ans. A. Oxbow lake

       An oxbow lake is formed when the meandering river across a flood plain forms cut offs.

B. Lagoons

     Spits and bars in the coastal areas formed by the depositional work of oceanic movement
forms a lagoon. Ex. Chilika lake (largest lake in India), Pulikat lake, Kolleru lake

C. Seasonal Lakes

     Lakes in the region of inland drainage are sometimes seasonal which depends upon the
rainfall. Ex. Sambhar lake in Rajasthan which is a salt water lake.

D. Glacial Lake

      These types of lakes are mostly found in Himalayan region. They are formed when glaciers
dug out a basin which was later filled snow melt. Ex. Wular lake in Jammu & Kashmir which is
the largest fresh water lake.

E. Artificial Lakes

    Damming of rivers for the generation of hydel power has also led to the formation of lakes.
Ex. Guru Gobind Sagar on Bhakra Nangal Project.

Q.25. Why lakes are important for human beings?

Ans. a. Regulate the flow of river

        Lakes help to regulate the flow of a river. During heavy rainfall, it prevents flooding and
during the dry season, it helps to maintain an even flow of water.

b. Generation of Hydel Power

        Damming of rivers is done in order to store the water for the generation of Hydro
electricity. Ex. Hirakud dam on Mahanadi river.

c. Promote Tourism

       Lakes are always an attraction for tourists for recreation. Lakes enhance the natural
beauty of the adjoining area and hence, promote tourism. Ex. Wular lake, Dal Lake in Jammu &
d. Moderate Climate

        Lakes also help in moderating the climate of the adjoining area that supports ecosystem
within the lake and also outside the lake.

e. Source of rivers

       Many lakes are also the major source for many rivers. Ex. Indus, Satluj, Brahamaputra
have their source in the Mansarovar lake.

Q.26. What is the role of a river in building up of an economy?

Ans. a. Cradle of Civilization

       River banks have attracted settlers from ancient times. All the major civilizations of the
world were settled near to the river banks. Ex. Indus Valley Civilization, Nile Civilization etc.
Even today, many important cities of the world are settled near to the river banks.

b. Basic Natural Resource

        Rivers have been of fundamental importance throughout the human history. Water from
the rivers is a basic natural resource, essential for various human activities.

c. Deposition of Sediments

        The deposition of sediments done by the rivers makes the river banks highly good for
cultivation, thus, promoting agriculture over there.

d. Other uses

        Using rivers for irrigation, navigation, hydro-power generation is of special significance
for a country.

Q.27. What are the main causes of increasing river pollution?

Ans. a. Industrial Effluents: A heavy load of untreated sewage and industrial effluents are
emptied into the rivers. This affects the quality of water and also the self cleansing capacity of
the river.

b. Urbanization: Modern trends of living consume more water. Moreover, the sewage problems
in cities have further added to the problem of water pollution.

c. Domestic Use: The use of rivers and lakes done for domestic purposes like washing and
bathing is adding to the problem of water pollution.

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