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SAI International School
                                             Grade-IX, Sub: Geography

                                                     Ch3- Drainage
                            Sub Topic- 1- Introduction, Drainage System in India



       Sub-topics      Lesson Notes

       Introduction  Drainage
       (Page no-          •  The term drainage refers to the river system of an area.
       17)                •  A river along with its tributaries and distributaries form a river system.
                          •  The area drained by a single river system is called a drainage basin or a river
                              basin.
                          •  Any elevated area such as a mountain or an upland separating two adjoining
                              drainage basins is known as water divide.
                          •  The world’s largest river basin is of the Amazon River and the basin of River
                              Ganga is India’s largest river basin.

       Drainage        Drainage System in India
       System in       The Indian rivers are divided into two major groups:
       India-             •  the Himalayan rivers
       ( Page No-         •   the Peninsular rivers
       !7,18)          Himalayan rivers
                          •  The three major Himalayan rivers are the river Indus, the river Ganga and the
                              river Brahmaputra.
                          •  These are perennial rivers which mean they carry water throughout the year.
                              They receive water from rain as well as from melted snow from the lofty
                              mountains of Himalayas.
                          •  The Himalayan Rivers have long courses from their source to the sea and are
                              joined by many large tributaries.
                          •  They perform intensive erosional activities in their upper course and cut
                              through the mountains making erosional features like waterfalls and gorges.
                          •  The Himalayan Rivers form meanders, oxbow lakes, floodplains and many
                              other depositional features in their middle and lower courses.
                       Peninsular rivers
                          •  Most of the rivers of peninsular India originate in the Western Ghats and flow
                              towards the Bay of Bengal. The major rivers are the Narmada, the Tapi, the
                              Godavari, the Mahanadi, the Krishna and the Kaveri.
                          •  They are seasonal and only rain-fed.
                          •  The Peninsular rivers have shorter and shallower courses as compared to
                              their Himalayan rivers.
                          •  They are comparatively less erosive.
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