Tuesday 4 November 2014

Smart Notes on Indian (Physical) Geography Part - 7



DRAINAGE & RIVER SYSTEMS

1.       The term drainage describes the river system of an area.
2.       The area drained by a single river system is called a drainage basin.

Water divide 

 Any elevated area, such as a mountain or upland, separates two drainage basins. Such an upland is known as a water divide


The world’s largest drainage basin is of the Nile River in Egypt

DRAINAGE SYSTEMS IN INDIA

1.       The drainage systems of India are mainly controlled by the broad relief features of the subcontinent.
2.       The Indian rivers are divided into two major groups:



The Himalayan Rivers

1.       Most of the Himalayan Rivers are perennial.
2.       The two major Himalayan Rivers, the Indus and the Brahmaputra originate from the north of the mountain ranges.
3.       They have cut through the mountains making gorges.
4.       The Himalayan Rivers have long courses from their source to the sea.
5.       They perform intensive erosional activity in their upper courses and carry huge loads of silt and sand.
6.       In the middle and the lower courses, these rivers form meanders, oxbow lakes, and many other depositional features

The Peninsular Rivers 

1.       A large number of the Peninsular Rivers are seasonal

The Himalayan Rivers

The major Himalayan Rivers are the Indus, the Ganga and the Brahmaputra.

River system -
A river along with its tributaries may be called a river system.

The Indus River System

1.       The river Indus rises in Tibet, near Lake Mansarowar.
2.       Flowing west, it enters India in the Ladakh district of Jammu and Kashmir.
3.       It forms a picturesque gorge in this part.
4.       Several tributaries, the Zaskar, the Nubra, the Shyok and the Hunza, join it in the Kashmir region.
5.       The Indus flows through Baltistan and Gilgit and emerges from the mountains at Attock.
6.       The Satluj, the Beas, the Ravi, the Chenab and the Jhelum join together to enter the Indus near Mithankot in Pakistan.
7.       Beyond this, the Indus flows southwards eventually reaching the Arabian Sea, east of Karachi.
8.       The Indus plain has a very gentle slope.
9.       With a total length of 2900 km
10.   A little over a third of the Indus basin is located in India in the states of Jammu and Kashmir, Himachal Pradesh and the Punjab and the rest is in Pakistan.

• According to the regulations of the Indus Water Treaty (1960), India can use only 20 per cent of the total water carried by Indus river system. This water is used for irrigation in the Punjab, Haryana and the southern and western parts of Rajasthan

The Ganga River System

1.       The headwaters of the Ganga, called the ‘Bhagirathi’ is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttaranchal.
2.       At Haridwar the Ganga emerges from the mountains on to the plains.
3.       The Ganga is joined by many tributaries from the Himalayas, a few of them being major rivers such as the Yamuna, the Ghaghara, the Gandak and the Kosi.
4.       The river Yamuna rises from the Yamunotri Glacier in the Himalayas.
5.       It flows parallel to the Ganga and as a right bank tributary, meets the Ganga at Allahabad
6.       The Ghaghara, the Gandak and the Kosi rise in the Nepal Himalaya.
7.       They are the rivers, which flood parts of the northern plains every year, causing widespread damage to life and property but enriching the soil for the extensive agricultural lands.
8.       The main tributaries, which come from the peninsular uplands, are the Chambal, the Betwa and the Son.
9.       These rise from semi-arid areas, have shorter courses and do not carry much water in them.
10.   The Ganga flows eastwards till Farakka in West Bengal.
11.   This is the northernmost point of the Ganga delta
12.   The river bifurcates here; the Bhagirathi-Hooghly (a distributary) flows southwards through the deltaic plains to the Bay of Bengal.
13.   The mainstream, flows southwards into Bangladesh and is joined by the Brahmaputra.
14.   Further downstream, it is known as the Meghna.
15.   The length of the Ganga is over 2500 km.
16.   Ambala is located on the water divide between the Indus and the Ganga river systems.
17.   The plains from Ambala to the Sunderban stretch over nearly 1800 km, but the fall in its slope is hardly 300 metres.
18.    In other words, there is a fall of just one metre for every 6 km. Therefore, the river develops large meanders.




Meghna
 This mighty river, with waters from the Ganga, and the Brahmaputra, flows into the Bay of Bengal. The delta formed by these rivers is known as the Sunderban delta. The Sundarban Delta derived its name from the Sundari tree which grows well in marshland, it is the world’s largest and fastest growing delta. It is also the home of Royal Bengal tiger.

The Brahmaputra River System

1.       The Brahmaputra rises in Tibet east of Mansarowar Lake very close to the sources of the Indus and the Satluj.
2.       It is slightly longer than the Indus, and most of its course lies outside India.
3.       It flows eastwards parallel to the Himalayas. On reaching the Namcha Barwa (7757 m), it takes a ‘U’ turn
4.       Enters India in Arunachal Pradesh through a gorge.
5.       Here, it is called the Dihang and it is joined by the Dibang, the Lohit, the Kenula and
6.       Many other tributaries to form the Brahmaputra in Assam
7.       Brahmaputra is known as the Tsang Po in Tibet and Jamuna in Bangladesh.
8.       In Tibet the river carries a smaller volume of water and less silt as it is a cold and a dry area
9.       In India it passes through a region of high rainfall.
10.   Here the river carries a large volume of water and considerable amount of silt.
11.   The Brahmaputra has a braided channel in its entire length in Assam and forms many riverine islands
12.   Unlike other north Indian rivers the Brahmaputra is marked by huge deposits of silt on its bed causing the river bed to rise. The river also shifts its channel frequently

The Peninsular Rivers

1.       The main water divide in Peninsular India is formed by the Western Ghats, which runs from north to south close to the western coast.
2.       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 Bengal.
3.       There are numerous small streams flowing west of the Western Ghats
4.       The Narmada and the Tapi are the only long rivers, which flow west and make estuaries.

The Narmada Basin

1.       The Narmada rises in the Amarkantak hills in Madhya Pradesh.
2.       It flows towards the west in a rift valley formed due to faulting.
3.       The ‘Marble rocks’, near Jabalpur where the Narmada flows through a deep gorge, and the ‘Dhuadhar falls’ where the river plunges over steep rocks, are some of the notable ones.
4.       The Narmada basin covers parts of Madhya Pradesh and Gujarat.

The Tapi

1.       The Tapi rises in the Satpura ranges, in the Betul district of Madhya Pradesh.
2.       It also flows in a rift valley parallel to the Narmada but it is much shorter in length.
3.       Its basin covers parts of Madhya Pradesh, Gujarat and Maharashtra.
4.       The coastal plains between Western Ghats and the Arabian Sea are very narrow.
5.       Hence, the coastal rivers are short. The main west flowing rivers are Sabarmati, Mahi, Bharathpuzha and Periyar. Find out the states in which these rivers drain the water.

The Godavari Basin

1.       The Godavari is the largest Peninsular River.
2.       It rises from the slopes of the Western Ghats in the Nasik district of Maharashtra.
3.       Its length is about 1500 km.
4.       It drains into the Bay of Bengal. Its drainage basin is also the largest among the peninsular rivers.
5.       The basin covers parts of Maharashtra (about 50 per cent of the basin area lies in Maharashtra), Madhya Pradesh, Orissa and Andhra Pradesh.
6.       The Godavari is joined by a number of tributaries such as the Purna, the Wardha, the Pranhita, the Manjra, the Wainganga and the Penganga.

Dakshin Ganga’
Because of its length and the area it covers, it is also known as the ‘Dakshin Ganga’

The Mahanadi Basin 

1.       The Mahanadi rises in the highlands of Chhattisgarh.
2.       It flows through Orissa to reach the Bay of Bengal.
3.       The length of the river is about 860 km. Its drainage basin is shared by Maharashtra, Chhattisgarh, Jharkhand, and Orissa.

The Krishna Basin

1.       Rising from a spring near Mahabaleshwar, the Krishna flows for about 1400 km and reaches the Bay of Bengal.
2.       The Tungabhadra, the Koyana, the Ghatprabha, the Musi and the Bhima are some of its tributaries.
3.       Basin is shared by Maharashtra, Karnataka and Andhra Pradesh.

The Kaveri Basin

1.       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.
2.       Total length of the river is about 760 km.
3.       Its main tributaries are Amravati, Bhavani, Hemavati and Kabini.
4.       Its basin drains parts of Karnataka, Kerala and Tamil Nadu
5.       The river Kaveri makes the second biggest waterfall in India. It is known as Sivasamudram. The fall supplies hydroelectric power to Mysore, Bangalore and the Kolar Gold Field.
6.       71 per cent of the world’s surface is covered with water, but 97 per cent of that is salt water. • Of the 3 per cent that is available as freshwater, three quarters of it is trapped as ice.

LAKES

1.       Lakes of large extent are called the seas, like the Caspian, the Dead and the Aral seas.
2.       A meandering river across a flood plain forms cut-offsthat later develop into ox-bow lakes.
3.       Spits and bars form lagoons in the coastal areas, eg the Chilika Lake, the Pulicat Lake, and the Kolleru Lake.
4.       Most of the fresh water lakes are in the Himalayan region. They are of glacial origin.
5.       In other words, they formed when glaciers dug out a basin, which was later filled with snowmelt.
6.       The Wular Lake in Jammu and Kashmir, in contrast, is the result of the tectonic activity. It is the largest freshwater lake in India.
7.       The Dal Lake, Bhimtal, Nainital, Loktak and Barapani are some other important fresh water lakes
8.       The damming of the rivers for the generation of hydel power has also led to the formation of Lakes such as Guru Gobind Sagar (Bhakra Nangal Project).
9.       Lakes are of great value to human beings. A lake helps to regulate the flow of a river.
10.   During heavy rainfall, it prevents flooding and during the dry season, it helps to maintain an even flow of water.
11.   Lakes can also be used for developing hydel power
12.   They moderate the climate of the surroundings;
13.   Maintain the aquatic ecosystem
14.   Enhance natural beauty, help develop tourism and provide recreation

ROLE OF RIVERS IN THE ECONOMY

1.       Rivers have been of fundamental importance throughout the human history.
2.       The river banks have attracted settlers from ancient times
3.       Using rivers for irrigation, navigation, hydro-power generation is of special significance

RIVER POLLUTION

1.       The growing domestic, municipal, industrial and agricultural demand for water from rivers naturally affects the quality of water.
2.       As a result, more and more water is being drained out of the rivers reducing their volume.
3.       A heavy load of untreated Sewage and industrial effluents are emptied into the rivers.
4.       This affects not only the quality of water but also the self-cleansing capacity of the river.
5.       Given the adequate stream flow, the Ganga water is able to dilute and assimilate pollution loads within 20 km of large cities.
6.       But the increasing urbanisation and industrialisation do not allow it to happen and the pollution level of many rivers has been rising.

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