India Physical Environment Chapter 3 Drainage System

The Characteristics:

On the basis of the size of the watershed, the drainage basins of India are grouped into three categories:

The Brahmaputra System:

The characteristics:
(i)These rivers are rainfed.

(ii)These rivers are of medium length.

(iii)These rivers are matured and their valleys are shallow.

The two headstreams of Ganga are :

(i) The Alaknanda
(ii) The Bhagirathi

The ill effects are:
(i)floods
(ii)channel shifting 
(iii)bank erosion.

The reasons are as follow :

(i)These are seasonal rivers which remain dried up in the summer.

(ii) River beds are uneven, rocky and have a steep gradients.

(iii) Construction of several dams also has made navigation through these rivers impossible.

The three main Himalayan river systems are:
(i) The Indus system.

(ii) The Ganga system

(iii) The Brahmaputra system.

(ii) It carries huge amount of silt.

(iii) It flows parallel to the Himalayan mountains in Tibet.

(iv) It takes U-turn at Namcha Barwa (height 7757 m) and enters into Arunachal Pradesh.

(v) It flows into the Bay of Bengal and the just before falling into it, it forms braided streams of the distributaries due to excess deposits of sediments and silts.

Trans - Himalayan rivers are :

(i)Indus

(ii)Brahmaputra

(iii)Satluj

Distributary : The water of the main river when finds no channels to flow forward, particularly when the silt, sediments and alluvium deposited at its mouth so enough as its forward flow is restricted; the force of river then cuts several small channels. These channels thus, distribute the integral force of the main river in several streams. E.g. Braided bed of Ganga-Brahmaputra delta in Assam and Bengal regions.

Hence, functionally, a tributary and a distributary are opposite to each-other. The former adds to while the later reduces to the force of the main river.

It rises in the Gangotri glacier near Gaumukh in the Uttarkashi district of Uttaranchal.

The socio-economic advantages of interlinking of rivers in India are followings:

(i)The surplus water can be transferred to the deficit areas.

(ii) When there is a flood in one part of the country the water can be used in other drought like areas for irrigation. Hydroelectricity can be generated in the areas by interlinking of rivers.
(iii) Interlinking of rivers will also have economic importance on a longer run. This can be used as inland waterways and which helps in faster movement of goods from one place to other.

Travelling from Haridwar to Siliguri, we have to cross the following rivers :

Ramganga, Gomati, Ghaghra, Rapti, Gandak, Kosi and Mahanadi.
Characteristics of Ghaghara :

(i)It originates in glacier of Mount Chachungo.

(ii)It collects the water of Tila Seti and Beri.

(iii)It cuts a deep gorge of600 m at Shishapani.

(iv)The river Sarda or Kali Ganga joins it in the plains.

(v)It meets Ganga at Chhapra.

(vi)Its length is 1080 km.

Reasons for their failure are all apparent:

(i) Rugged, metamorphic rocks are in their beds hence, these flow in narrow passages. These being regions of old mountains and the table land, it is hard to cut-off the banks by these rivers and spread the silt carried by them to make it a delta. Bifurcation of three sides is nowhere possible for the channels of these rivers. Hence, we see basins as fertile as the deltas.

(ii) All tributaries of these rivers make trellis pattern because of their confluence at right angles.

(iii) We see basin formed by the rivers flowing on western coast (the Narmada and the Tapi rivers with their tributaries—Baiyer, Dudhi, Tawa, Hiran, Purna, Betul and Lavda). These basins cover Madhya Pradesh and Gujarat states. Similarly, the Tapi river has formed its basin in the parts of Madhya Pradesh, Gujarat and Maharashtra states.

We can ascribe the physical conditions responsible for deficiency of non-making deltas by these rivers.

(i)Ganga-Brahmaputra delta.
(ii)Mahanadi delta.
(iii)Krishna delta.
(iv)Kaveri delta.

Ans. Watershed : Watershed is an area which is drained by a river. It is demarcated by a line that separates the watershed of one river from the adjoining ones. These are small areas less than 1000 hectares.

River basin : The watersheds of large rivers are called river basin.

(ii) Delta and Estuary.

Ans. Delta : A delta is a triangular piece of alluvial low land formed at the mouth of the

river. It is formed due to deposition by the river at its lower course.

Estuary : Those rivers which do not form deltas, form estuaries. These rivers do not deposit sediments on their mouth, and carry the materials into the sea or ocean. This mouth is called estuary. Example : Narmada and Tapi make estuaries.

Characteristics of North Indian rivers :

(i)The North Indian rivers have evolved through a long geological history.

(ii)It includes Ganga, Brahmaputra and Indus river basins.

(iii)These are fed by melting of snow and precipitation.

(iv)These are perennial rivers.

(v)These rivers form deep gorges and V-shaped valleys in mountainous areas and when they enter plains they form flat valleys, flood plains etc.

The northern rivers differ from the peninsular rivers in the following ways :

(i)The catchment areas of northern rivers are large while the catchment areas of peninsular rivers are small.

(ii)The northern rivers flow in deep gorges in the mountains and they form meanders in plains; while peninsular rivers do not have formations.

(iii)Northern rivers are perennial as they derive their water from snow melt and rainfall while peninsular rivers depend on only monsoons.

It is also believed that this mighty river carried the combined flow of the Himalaya rivers and the main streams of the Brahmaputra, Ganga and the Indus.

The sediments brought by this mighty river formed the Siwalik range. Due to the uplift of the western Himalayas, the mighty stream dismembered into the following river systems and sub-systems :

(i) The Indus system.

(ii) The five tributaries of the Indus in Punjab.

(iii) The Ganga and its Himalayan tributaries.

This dismemberence changed direction of present Ganga and Yamuna. According to this theory, the Yamuna was the tributary of Indus before this event took place and had southwesterly course. This interchange of tributaries between the Indus and the Ganga systems in the region lying between the headstreams of the Sutlej and Yamuna has been a common phenomenon in the geologic recent past.

Arguments Against the Theory : The theory of Indo-Brahma has not been accepted universally. It has been challenged on the following grounds :

Firstly, the concept of such a mighty river Indo-Brahma flowing all along the longitudinal

extent of the Himalayas is not possible. The occurrence of Siwalik alluvial deposits might have been formed by successive deposition of alluvial fans by the rivers flowing down the Himalayan slopes.

Secondly, the evidence furnished by the depositional history in the Ganga delta and in the Assam does not prove this concept as the deposits in the gap lying between the two projections of the peninsular block-Rajmahal hills and Shillong plateau, have been composed of thick alluvium older than that suggested by the Indo-Brahma theory

Thirdly, the evidences of Tipan sandstorm of Assam has not been accepted by this theory.

Centripetal drainage : The rivers flowing into a depression or a lake, is called a centripetal drainage. The desert is characterised by the centripetal drainage pattern.

Rift valley : Rift valleys are formed due to faulting. Due to the internal disturbances of the earth, some regions sink and form a valley. This valley is called a rift valley.

The distinction:

(ii)Cumecs : When the water flowing in the river is measured in cubic metre per second, it is called cumecs.

The Ganga : As its hydrograph shows that the flow pattern of the Ganga attains the sizeable flow in the early summer because of snow-melting. Its maximum flow is either in August or September and minimum in the period of December and January.

The Godavari : As its hydrograph shows that the flow pattern of Godavari river has also seasonal effects. Its flow is low until May. It has two inaximas-one in May-June and other in July-August. After August, its flow pattern falls sharply but it has higher flow in October and November also.

The Narmada : The hydrograph shows that the flow pattern of Narmada is also seasonal. It is high in the. months of June to September and October during the rainy season. During winter it is low.

The Jhelum : The flow pattern of Jhelum is high throughout the year, because it is due to snow melting and rainfall in the region.

The term drainage is technically used for the river system of an area. India's drainage system is grouped in (i) The Himalayan rivers and (ii) The Peninsular rivers. Apart from this, there are inland drainage systems also.

The Himalayan rivers are the Indus, the Ganges and the Brahmaputra. The Indus water drains only 17,844 sq. km area in India because it flows outside the border of India since its rise from the Kailash range of Greater Himalayas. Its tributaries are the Zaskar, Shyok, Jhelum, Chenab, Ravi, Beas and Satluj. Indus is one of the largest river basins in the world, but its course in India is only 709 km.

The Ganges rises from Gangotri glacier and at the beginning, it is called Bhagirathi. Alaknanda meets it at Devprayag in Garhwal region and then it is named as Ganga. The Ganga with its tributaries viz. Yamuna, Ghaghra, Gandak, Kosi, Son, Chambal and Betwa drains 9,51,600 sq. km area and falls into the Bay of Bengal.

Brahmaputra rises from the Kailash range of Greater Himalayas near Mansarover. It flows eastwards parallel to the Himalayas to its south. It enters into India west of Sadiya town in Arunachal Pradesh. Its tributaries are Raja Tsangpo, Lhotse, Subansiri, Tista, Torsa and Dihang. It is long as the Indus and drains 5,80,000 sq. km area in India.

All these three major rivers fall into the Bay of Bengal.

Among Peninsular rivers, there are the Narmada, the Tapi, the Mahanadi, the Godavari, the Krishna and the Kaveri known as major rivers. The length of the Narmada and the Tapi are 1300 and 792 km respectively. The area drained by them is 93,080 and 792 sq. km respectively. These fall into the Arabian sea. Mahanadi rises in Chhattisgarh with its length 885 km and area drained is 1,92,000 sq. km Godavari rises in Nasik (Maharashtra). Its length is 1400 km and area drained by it is 2,60,000 sq. km. Kaveri rises from Brahmagiri hills. It drains 72,000 sq. km area and its length is 765 km. All these fall into the Bay of Bengal.

According to the slope of land, underlying rock structure and climatic conditions of the area, the rivers form dendritic (tree-like shapes), trellis, rectangular, radial and centifugal patterns. Ghaghar river of Haryana forms the centrifugal pattern of inland drainage.

The Himalayan rivers are perennial but the peninsular rivers are seasonal at the most. Owing to different rock structures, these form estuaries, gorges, water divide, rift valleys, basins, delta, doab etc. land-forms. Ganga-Brahmaputra delta or the Sunderban delta is the largest delta in the world.

Lakes are grouped into two i.e. (i) Natural lakes, (ii) Man-made lakes (or dams). Some natural lakes are Wulur, Dal, Nainital, Bhimtal, Loktak, Barapani, Chilka, Sambhar, Vembanad, Pulicat. Man-made lakes are : Govindsagar (Bhakra), Ranapratap Sagar, Nizamsagar, Nagarjunsagar, Gandhi Sagar and Hirakud. Some lakes are formed owing to the action of glaciers and ice sheets while some other are formed by wind, river action and human activities.

D.

C.

C.

B.

D.

Brahmaputra and kosi river.

Ganga-Brahmaputra delta.

The Brahmaputra

(ii) It carries huge amount of silt.

(iii) It flows parallel to the Himalayan mountains in Tibet.

(iv) It takes U-turn at Namcha Barwa (height 7757 m) and enters into Arunachal Pradesh.

(v) It flows into the Bay of Bengal and the just before falling into it, it forms braided streams of the distributaries due to excess deposits of sediments and silts.

Arguments Against the Theory : The theory of Indo-Brahma has not been accepted universally. It has been challenged on the following grounds :

Firstly, the concept of such a mighty river Indo-Brahma flowing all along the longitudinal extent of the Himalayas is not possible. The occurrence of Siwalik alluvial deposits might have been formed by successive deposition of alluvial fans by the rivers flowing down the Himalayan slopes.

Secondly, the evidence furnished by the depositional history in the Ganga delta and in the Assam does not prove this concept as the deposits in the gap lying between the two projections of the peninsular block-Rajmahal hills and Shillong plateau, have been composed of thick alluvium older than that suggested by the Indo-Brahma theory.
Thirdly, the evidences of Tipan sandstorm of Assam has not been accepted by this theory.

Reasons for their failure are all apparent:

(i) Rugged, metamorphic rocks are in their beds hence, these flow in narrow passages. These being regions of old mountains and the table land, it is hard to cut-off the banks by these rivers and spread the silt carried by them to make it a delta. Bifurcation of three sides is nowhere possible for the channels of these rivers. Hence, we see basins as fertile as the deltas.

(ii) All tributaries of these rivers make trellis pattern because of their confluence at right angles.

(iii) We see basin formed by the rivers flowing on western coast (the Narmada and the Tapi rivers with their tributaries—Baiyer, Dudhi, Tawa, Hiran, Purna, Betul and Lavda). These basins cover Madhya Pradesh and Gujarat states. Similarly, the Tapi river has formed its basin in the parts of Madhya Pradesh, Gujarat and Maharashtra states.

We can ascribe the physical conditions responsible for deficiency of non-making deltas by these rivers.

(i) The Indus River System : It is one of the largest river basins of the world covering an area of 1165000 sq. km. It carries about 73.31 cubic km of water out of which India can utilise only 46 cubic km. The Indus river originates in the Tibetan region at an altitude of 4164 m in Kailash Mountain range.

Jhelum is an important tributary of the Indus. It rises from a spring at Verinag situated at the foot of Pir Panjal in Southeastern part of the valley of Kashmir. Out of its total drainage area of this basin, only 28490 sq. km lies in India.

The Chenab is the largest tributary of the Indus. The Ravi also known as the Iravati is another important tributary of the Indus. It rises west of the Rohtang pass in Kullu hills of Himachal Pradesh and flows through the Chamba Valley of the State. It covers a drainage area of 5957 sq. km in India.

The Beas also known Vipasha or Argikiya is another important river tributary of the Indus. It originates from Beas Kund near the Rohtang Pass at an elevation of 4000 m.

Satluj or Satudri, an important tributary of the Indus, originates in the Rakas lake near Mansarovar at an altitude of 4555 m in Tibet.

(ii) The Ganga System : Ganga is the important river of India both from the point of view of its basin and cultural significance. It rises in Gangotri glacier near Gomukh (3900 m) in Uttaranchal. Its main tributary is Yamuna. Other rivers are -Chambal, Sindh, Betawa and Kosi. In the northern side the tributaries are Gandak, Ghaghara, Sarda, Gomati, Kosi, Ramganga etc. Damodar occupies the eastern margin and joins the Hugli.

(iii) Brahmaputra System : Brahmaputra, one of the largest rivers of the world, has its origin in Chamyung glacier of Kailash range near Mansarover lake. In Tibet, it is known as Tsangpo.

The Brahmaputra receives numerous tributaries in its 750 km long journey in the Assam Valley

The Brahmaputra receives numerous tributaries in its 750 km long journey in the Assam Valley

The Indus System: 

The Ganges rises from Gangotri glacier and at the beginning, it is called Bhagirathi. Alaknanda meets it at Devprayag in Garhwal region and then it is named as Ganga. The Ganga with its tributaries viz. Yamuna, Ghaghra, Gandak, Kosi, Son, Chambal and Betwa drains 9,51,600 sq. km area and falls into the Bay of Bengal.

Brahmaputra rises from the Kailash range of Greater Himalayas near Mansarover. It flows eastwards parallel to the Himalayas to its south. It enters into India west of Sadiya town in Arunachal Pradesh. Its tributaries are Raja Tsangpo, Lhotse, Subansiri, Tista, Torsa and Dihang. It is long as the Indus and drains 5,80,000 sq. km area in India.

All these three major rivers fall into the Bay of Bengal.