CLASS 9 GEOGRAPHY CHAPTER 2 , DRAINGE

DRAINGE

• The term Drainage describes the river system of an area.
•  Small streams following from different direction come together to form the main river, which ultimately drains into a large water body such as a lake or sea or an Ocean.
•  The area drained by a singer River system is called a Drainage Basin.
• 
  
                                                               Water Divide 

Drainage system in India 

• The drainage system of India mainly controlled by the broad relief feature of the subcontinent.
•  Accordingly, the Indian rivers are divided into two major groups :

1. The Himalayan rivers 
2.  The peninsula rivers 

• The peninsular rivers are different from each other in many ways.
•  Most of Himalayan River are perennial. 
•  It mean that they have water throughout the year.
•  This river received water from rains as well as from melted snow from the lofty mountains.
•  The two major Himalayan River the Indus and the Brahmaputra originate from the north of mountain range.
•  The Himalayan River have long courses from their source to the sea they perform intensive erosional activity in their upper courses and carry use loads of slit and sand.
• In the middle and the lower courses, these rivers from meanders, oxbow lake and many other depositional features in their floodPlains.
• They are also have well developed deltas.
• 
                                                   Some features made by Rivers
  
  
•  A large number of peninsular rivers are seasonal ,as their flow is dependent on rainfall .
• During the dry season, even the large rivers have reduced flow of water in their channels .
• The Peninsular river have shorter and shallower  courses as compared to their Himalayan counterparts. 

The Himalayan rivers 

• The major Himalayan rivers are the Indus, the Ganga and the Brahmaputra .
• These river are long ,and are joined by many large and important tributaries.
•  A river along with its tributaries may be called a River system.

The Indus River system 

• The river Indus series in Tibet ,near Lake Manasarovar.
•  flowing West, it enters India in the Ladakh district of Jammu and Kashmir.
•  It forms picturesque gorge in this part .
• Several tributaries, the Zaskar,  the nubra,  the human, join it in the Kashmir reason.
•  The Indus flow throughs Baltistan and Gilgit emerged from the mountain at Attock. 
•  The Satluj, the beas, the ravi ,the Chenab and the Jhelum join together to enter the Indus near Mithankot in Pakistan .
• Beyond this, the Indus flows southwards eventually reaching the Arabian Sea, east of Karachi .
• The Indus plain has a very gentle slope.
• With a total and length of 2900 km, the Indus is one of the longest rivers of the world .
• A little  over a third of the Indus basin is located in India in the states of Jammu and Kashmir, Himachal Pradesh and Punjab and the rest in Pakistan.

The Ganga River system

• The headquarters of the Ganga called the 'Bhagirathi' is fed by the Gangotri Glacier and joined by the Alkananda at devaprayag in Uttarakhand.
•  At Haridwar, Ganga emerges from the mountains on to the plains. 
• 
                                   confluence of Bhagirathi and Alaknanda at Devaprayag
  
  
• The Ganga is joined by the many tributaries from the Himalayas, a few of them being major rivers, such as the Yamuna ,the Ghaghra ,gandak and the Kosi.
•  The river Yamuna Rises from the Yamunotri glacier in the Himalayas. it follows parallel to the Ganga and as a right bank tributary meets the Ganga at Allahabad.
•  The Ghaghara , the Gandak and the Kosi rise in the Nepal Himalaya .they are the rivers ,which flood parts of the northern plains every year ,causing widespread damage to life and property, whereas, they enrich the soil for agriculture use .
• The main tributaries,  which come from the Peninsula a uplands,  are the Chambal the Betwa and the son . These rise from semi - arid areas , have shorter courses and do not carry much water in them.
• Enlarged with the waters from its right and left Bank tributaries ,the Ganga flows eastwards till Farakka in West Bengal .
• This is the northernmost point of the Ganga delta .
• The river bifurcates here', the Bhagirathi -Hooghly (a distributary) flows Southwards Through The Deltaic Plains to the Bay of Bengal . this mainstream, flows South words into Bangladesh and is joined by the Brahmaputra. further downstream it is known as the Meghan. 
•  This mighty river, with waters from the Ganga and the Brahmaputra flows into the Bay of Bengal are the Delta formed by these rivers is known as the Sundarban delta.
• The length of the Ganga is over 2500 kilometre Ambala is located on the water divide between the Indus and the Ganga river systems.
•  The plains from Ambala to the Sundarban stretch over nearly 1800 km but the fall in its slope is hardly 300 metres .in the other words, there is a fall of just one for every 6 km .therefore, the river develops large meanders.

The Brahmaputra River system

• The Brahmaputra Rises in Tibet east of Mansarovar Lake every close to the source of the industry and the Satluj.
•  It is slightly longer than the indus ,and most of its course lies outside India.
•  It flows Eastwards parallel to the Himalayas. On reaching the namcha Barwa (7757m), it takes a 'U' turn and enters India in Arunachal Pradesh through a Gorge. here, it is called the dihang and it is fixing,  the Lohit , and many other tributaries to form the Brahmaputra in Assam.
• In Tibet, the river carries a smaller volume of water and less slit as it is a cold and a dry area in India , it passes through a reason of high rainfall .
• Here the river carries a large volume of water and considerable amount of Silt.
•  The Brahmaputra has a braided channel in its entire length in Assam and forms many riverine islands.
• Every year during the rainy season, the river overflows its banks, causing widespread devastation due to floods in Assam and Bangladesh .unlike other North Indian rivers , the Brahmaputra is marked by huge deposits of slit on its bed causing the riverbed to rise . The river also shifts its channel frequently.

The Peninsular Rivers 

• The main water divide in Peninsular India is formed by the Western Ghats which runs from north to south close to The Western coast.
•  Most of the major rivers of the Peninsula ,such as the Mahanadi, the Godavari, the Krishna and the Kaveri flow Eastwards and drain into the Bay of Benga.
• These rivers make deltas at their mouths. there are numerous small streams flowing west of the Western Ghats.
•  The Narmada and the Tapi are the only long rivers ,which flow west and make esturies. 
•  The drainage basins of the peninsular rivers are comparatively smaller in size.

The Narmada basin

• 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 runs over steep  rocks , are some of the notable ones. 
• 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.

The Tapi basin

• 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 basing covers part of Madhya Pradesh, Gujarat and Maharashtra.
•  The coastal plain between Western Ghat and the Arabian Sea are very narrow.
•  Hence, the coastal rivers are short. The main West following rivers the Sabarmati ,Mahi , Bharathpuzha and periyar. 

The Godavari basin

• The Godavari is the largest Peninsular river
•  It Rises from the slopes of the Western Ghats in the Nashik district of Maharashtra its length is about 1500 km.
•  It drains into the Bay of Bengal. It's drainage basin is also the largest among the peninsular rivers .
• The basin covers  parts of Maharashtra (about 50% of the basin area lies in the 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,  wainganga and the penganga .
• The last three tributaries are very large. because of its length and the area it covers, it is also known as the Dakshin Ganga.

The Mahanadi basin

• The Mahanadi rise in the Highlands of Chhattisgarh.
•  It flows through Odisha to reach the Bay of Bengal are the length of the river is about 860 km.
•  It's drainage basin is shared by Maharashtra, Chhattisgarh, Jharkhand and the Odisha.

The Krishna basin

• Rising 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.
•  It's drainage basin is shared by Maharashtra, Karnataka and Andhra Pradesh.

The Kaveri basin 

• 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 Tuributaries are Amravati, Bhavani, Hemavati and kabini.
•  Its basin drains parts of Karnatak Kerala and tamil Nadu.
•  Besides these major rivers, there are some smaller river flowing towards the east.
•  The Damoder, the Brahmani, the Baitarni  and the subarnarekha are some notable examples.

Lakes

• India has many lakes .these differ from each other in size and other characteristics most lakes are permanent ,some contain water only during the rainy season, like the lakes in the basis of Inland drainage of semi arid regions.
•  There are some lakes which are the result of the action of glaciers and ise seats while others have been formed by wind, river action and human activities.
•  A meandering river across of floodplain forms cut - offs that later developed into ox-bow lakes .
• spits and bars from lagoons in the coastal areas ,example the Chilika Lake ,the Pulicat Lake and the Kolleru Lake .
• Lakes in the region of Inland drainage are sometime seasonal ,for example, the Sambhar Lake in Rajasthan, which is a salt water lake.its water is used for producing salt .
• Most of the freshwater lakes are in the Himalaya region. 
•  They are of glacial origin.
•  In the other words , they formed when Glaciers dug out a basin,  which was later filled with snowmelt .
• The Wular lake in Jammu and Kashmir, in contrast,  is the result of tectonic activity.
•  It is the largest freshwater lake in India. The Dal lake, Bhimtal ,Nainital , loktak and Barapani are some other important freshwater lakes.
• 
  
                                                                      Loktak Lake 
• Apart from natural lakes the damming of the rivers for the generation of Hydel power has also led to the formation of lakes , such as Guru govind Sagar (Bhakra Nangal project).
• 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 and even flow water.
•  lakes can also be used for developing Hydel power .
• The moderate the climate of the surrounding ', maintain the aquatic ecosystem, enhance  natural beauty ,help develop tourism and provide recreation.

Roles of rivers in the economy

• Rivers hasbeens of fundamental important throughout the human history .
• Water from river is a basic natural resource essential for various human activities .
• Therefore , riverbanks have attracted settled from ancient times.
•  These settlements have now become big cities .
• Using rivers for irrigation, navigation ,hydro - power generation is of special significance - particularly to a country like India, where agriculture is the major source of livelihood of the majority of its population.

River pollution

• The growing domestic, Municipal ,Industrial and Agriculture demand for water from rivers naturally affect the quality of water .
• As a result , it more and more water is being drained out of the rivers reducing their volume on the other hand, a heavy load of untreated sewage and industrial effluents are empited  into the rivers.
•  This affects not only the quality of water but also the self - cleaning  capacity of the rivers. for example , given the adequate streamflow ,the Ganga water is able to dilute and assimilate pollution loads within 20 km of large cities.
•  But the increasing urbanisation and industrialization do not allow it to happen and the pollution level of many rivers has been rising.
•  Concern over rising pollution in our rivers led to the launching of various action plan to clean the rivers.