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Chapter 9_3: Geo9_3_drainage

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

DRAINAGE SYSTEMS IN INDIA

Two major groups: • the Himalayan rivers; and • the Peninsular rivers.

Most of the Himalayan Rivers are perennial. It means that they have water throughout the

year.

The two major Himalayan Rivers, the Indus and the Brahmaputra originate from the north of

the mountain ranges.

Most of the rivers of peninsular India originate in the Western Ghats and flow towards the

Bay of Bengal.

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The Himalayan Rivers

The major Himalayan Rivers are the Indus, the Ganga and the Brahmaputra. These rivers 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 rises in Tibet, near Lake Mansarowar. Flowing west, it enters India in the

Ladakh district of Jammu and Kashmir.

• 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

The headwaters of the Ganga, called the ‘Bhagirathi’ is fed by the Gangotri Glacier and

joined by the Alaknanda at Devaprayag in Uttaranchal. At Haridwar the Ganga emerges from

the mountains on to the plains.

• 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 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.

Enlarged with the waters from its right and left bank tributaries, the Ganga flows eastwards

till Farakka in West Bengal

Ambala is located on the water divide between the Indus and the Ganga river systems.

The Brahmaputra River System

The Brahmaputra rises in Tibet east of Mansarowar Lake very close to the sources of the

Indus and the Satluj.

On reaching the Namcha Barwa (7757 m), it takes a ‘U’ turn and enters India in Arunachal

Pradesh through a gorge

Brahmaputra is known as the Tsang Po in Tibet and Jamuna in Bangladesh.

The Peninsular Rivers

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.

The Narmada and the Tapi are the only long rivers, which flow west and make estuaries

The Narmada Basin

The Narmada raises in the Amarkantak hills in Madhya Pradesh.

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

The Narmada basin covers parts of Madhya Pradesh and Gujarat

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The Tapi Basin

The Tapi raises in the Satpura ranges, in the Betul district of Madhya Pradesh.

Its basin covers parts of Madhya Pradesh, Gujarat and Maharashtra.

Hence, the coastal rivers are short. The main west flowing rivers are 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 Nasik district of Maharashtra. Its length is about 1500 km.

The Godavari is joined by a number of tributaries such as the Purna, the Wardha, the

Pranhita, the Manjra, the 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 rises in the highlands of Chhattisgarh. It flows through Orissa to reach the Bay of

Bengal. The length of the river is about 860 km. Its drainage basin is shared by Maharashtra,

Chhattisgarh, Jharkhand, and Orissa

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.

Its drainage basin is shared by Maharasthra, 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

Its main tributaries are Amravati, Bhavani, Hemavati and Kabini. Its basin drains parts of

Karnataka, Kerala and Tamil Nadu.

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.

LAKES

• Lakes of large extent are called the seas, like the Caspian, the Dead and the Aral seas.

The Chilika lake, the Pulicat lake, the Kolleru lake. Lakes in the region of inland drainage are

sometimes seasonal; for example, the Sambhar Lake in Rajasthan, which is a salt water lake.

Its water is used for producing salt.

The Wular Lake in Jammu and Kashmir, in contrast, is the result of the tectonic activity.

It is the largest freshwater lake in India. The Dal Lake, Bhimtal, Nainital, Loktak and Barapani

are some other important fresh water lakes.

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 Gobind Sagar (Bhakra Nangal Project)

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ROLE OF RIVERS IN THE ECONOMY

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 agricultural demand for water from rivers

naturally affects the quality of water.

On the other hand, a heavy load of untreated sewage and industrial effluents are emptied

into the rivers. This affects not only the quality of water but also the self -cleansing capacity

of the river.

National River Conservation Plan (NRCP)

The activities of Ganga Action Plan (GAP) phase-I, initiated in 1985, were declared closed on

31st March 2000.

The Steering Committee of the National River Conservation Authority reviewed the progress

of the GAP and necessary correction on the basis of lessons learnt and experiences gained

from GAP Phase-I.

These have been applied to the major polluted rivers of the country under the NRCP. The

Ganga Action Plan (GAP) Phase-II, has been merged with the NRCP.

The expanded NRCP now covers 152 towns located along 27 interstate rivers in 16 states.

Under this action plan, pollution abatement works are being taken up in 57 towns.

A total of 215 schemes of pollution abatement have been sanctioned. So far, 69 schemes

have been completed under this action plan. A million litres of sewage is targeted to be

intercepted, diverted and treated.

Chapter

All water moves within the hydrological cycle ensuring that water is a renewable resource

• 96.5 per cent of the total volume of world’s water is estimated to exist as oceans and onl y

2.5 per cent as freshwater.

• Nearly 70 per cent of this freshwater occurs as ice sheets and glaciers in Antarctica,

Greenland and the mountainous regions of the world, while a l ittle less than 30 per cent is

stored as groundwater in the world’s aquifers.

• India receives nearly 4 per cent of the global precipitation and ranks 133 in the world in

terms of water availability per person per annum

• The total renewable water resources of India are estimated at 1,897 sq km per annum

• By 2025, it is predicted that large parts of India will join countries or regions having absolute

water scarcity.

Source: The UN World Water Development Report, 2003

According to Falken Mark, a Swedish expert, water stress occurs when water availability is

less than 1,000 cubic meter per person per day.

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To facilitate higher food-grain production, water resources are being over-exploited to

expand irrigated areas and dry- season agriculture.

That it may lead to falling groundwater levels, adversely affecting water availability and food

security of the people

Post-independent India witnessed intensive industrialisation and urbanisation, creating vast

opportunities for us

Today, in India hydroelectric power contributes approximately 22 per cent of the total

electricity produced.

There has been a growing concern that even if there is ample water to meet the needs of

the people, much of it may be polluted by domestic and industrial wastes, chemicals,

pesticides and fertilisers used in agriculture, thus, making it hazardous for human use

WATER SCARCITY AND THE NEED FOR WATER CONSERVATION AND MANAGEMENT

India’s rivers, especially the smaller ones, have all turned into toxic streams. And even the big ones

like the Ganga and Yamuna are far from being pure. The assault on India’s rivers – from population

growth, agricultural modernisation, urbanisation and industrialisation – is enormous and growing by

the day….. This entire life stands threatened

MULTI-PURPOSE RIVER PROJECTS AND INTEGRATED WATER RESOURCES MANAGEMENT

Hydraulic Structures in Ancient India

In the first century B.C., Sringaverapura near Allahabad had sophisticated water harvesting

system channeling the flood water of the river Ganga.

During the time of Chandragupta Maurya, dams, lakes and irrigation systems were

extensively built.

Evidences of sophisticated irrigation works have also been found in Kalinga, (Orissa),

Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra), etc.

In the 11th Century, Bhopal Lake, one of the largest artificial lakes of its time was built.

In the 14th Century, the tank in Hauz Khas, Delhi was constructed by Iltutmish for supplying

water to Siri Fort area

Today, dams are built not just for irrigation but for electricity generation, water supply for domestic

and industrial uses, flood control, recreation, inland navigation and fish breeding.

The Sutluj-Beas river basin, the Bhakra – Nangal project water is being used both for hydel

power production and irrigation. Similarly, the Hirakud project in the Mahanadi basin

integrates conservation of water with flood control

Dams are classified as timber dams, embankment dams or masonry dams, with several

subtypes. According to the height, dams can be categorized as large dams and major dams

or alternatively as low dams, medium height dams and high dams

Jawaharlal Nehru proudly proclaimed the dams as the ‘temples of modern India’; the reason being

that it would integrate development of agriculture and the village economy with rapid

industrialisation and growth of the urban economy.

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Multi-purpose projects and large dams have also been the cause of many new social movements like

the ‘Narmada Bachao Andolan’ and the ‘Tehri Dam Andolan’ etc.

Narmada Bachao Andolan or Save Narmada Movement is a Non-Governmental Organisation

(NGO) that mobilised tribal people, farmers, environmentalists and human rights activists

against the Sardar Sarovar Dam being built across the Narmada river in Gujarat.

In Gujarat, the Sabarmati-basin farmers were agitated and almost caused a riot over the

higher priority given to water supply in urban areas, particularly during droughts.

Inter-state water disputes are also becoming common with regard to sharing the costs and

benefits of the multi-purpose project

The Krishna-Godavari dispute is due to the objections raised by Karnataka and Andhra

Pradesh governments. It is regarding the diversion of more water at Koyna by the

Maharashtra government for a multipurpose project. This would reduce downstream flow in

their states with adverse consequences for agriculture and industry.

RAIN WATER HARVESTING

Roof top rain water harvesting is the most common practice in Shillong, Meghalaya. It is

interesting because Cherapunjee and Mawsynram situated at a distance of 55 km. from

Shillong receive the highest rainfall in the world, yet the state capital Shillong faces acute

shortage of water.

Nearly every household in the city has a roof top rain water harvesting structure. Nearly 15-

25 per cent of the total water requirement of the household comes from roof top water

harvesting.

Tamil Nadu is the first and the only state in India which has made roof top rainwater

harvesting structure compulsory to all the houses across the state. There are legal provisions

to punish the defaulters.

Chapter 11_3: Geo11_3_India_Drainage System

The drainage pattern of an area is the outcome of the geological time period, nature and

structure of rocks, topography, slope, amount of water flowing and the periodicity of the

flow

A river drains the water collected from a specific area, which is called its ‘catchment area’.

An area drained by a river and its tributaries is called a drainage basin. The boundary line

Separating one drainage basin from the other is known as the watershed. The catchme nts of

large rivers are called river basins while those of small rivulets and rills are often referred to

as watersheds.

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Watersheds are small in area while the basins cover larger areas.

It may be grouped into:

the Arabian Sea drainage; and

The Bay of Bengal drainage.

They are separated from each other through the Delhi ridge, the Aravalis and the Sahyadris .

Nearly 77 per cent of the drainage area consisting of the Ganga, the Brahmaputra, the

Mahanadi, the Krishna, etc. is oriented towards the Bay of Bengal.

23 per cent comprising the Indus, the Narmada, the Tapi, the Mahi and the Periyar systems

discharge their waters in the Arabian Sea

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

categories:

Major river basins with more than 20,000 sq. km of catchment area. It includes 14 drainage

basins such as the Ganga, the Brahmaputra, the Krishna, the Tapi, the Narmada, the Mahi,

the Pennar, the Sabarmati, the Barak, etc.

Medium river basins with catchment area between 2,000-20,000 sq. km incorporating 44

river basins such as the Kalindi, the Periyar, the Meghna, etc.

Minor river basins with catchment area of less than 2,000 sq. km include fairly good number

of rivers flowing in the area of low rainfall

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A mighty river called Shiwalik or Indo-Brahma traversed the entire longitudinal extent of the

Himalaya from Assam to Punjab and onwards to Sind, and finally discharged into the Gulf of Sind

near lower Punjab during the Miocene period some 5-24 million years ago

The remarkable continuity of the Shiwalik and its lacustrine origin and alluvial deposits consisting of

sands, silt, clay, boulders and conglomerates support this viewpoint

It is opined that in due course of time Indo– Brahma River was dismembered into three main

drainage systems:

The Indus and its five tributaries in the western part;

The Ganga and its Himalayan tributaries in the central part; and

The stretch of the Brahmaputra in Assam and its Himalayan tributaries in the eastern part.

The dismemberment was probably due to the Pleistocene upheaval in the western

Himalayas, including the uplift of

The Potwar Plateau (Delhi Ridge), which acted as the water divide between the Indus and Ganga

drainage systems. Likewise, the down thrusting of the Malda gap area between the Rajmahal hills

and the Meghalaya plateau during the mid-Pleistocene period diverted the Ganga and the

Brahmaputra systems to flow towards the Bay of Bengal.

The Indus also known as the Sindhu is the westernmost of the Himalayan Rivers in India.

It originates from a glacier near Bokhar Chu (31°15' N latitude and 81°40' E longitude) in the Tibetan

region at an altitude of 4,164 m in the Kailash Mountain range.

The Panjnad is the name given to the five rivers of Punjab, namely the Satluj, the Beas, the Ravi, the

Chenab and the Jhelum.

The Chenab is the largest tributary of the Indus. It is formed by two streams, the Chandra and the

Bhaga, which join at Tandi near Keylong in Himachal Pradesh. Hence, it is also known as

Chandrabhaga.

The Ganga river system is the largest in India having a number of perennial and non-perennial rivers

originating in the Himalayas in the north and the Peninsula in the south, respectively. The Son is its

major right bank tributary. The important left bank tributaries are the Ramganga, the Gomati, the

Ghaghara, the Gandak, the Kosi and the Mahanada. The river finally discharges itself into the Bay of

Bengal near the Sagar Island.

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The Yamuna, the western most and the longest tributary of the Ganga

Once known as the ‘sorrow of Bengal’, the Damodar has been now tamed by the Damodar

Valley Corporation, a multipurpose project

The Ganga has its minimum flow during the January-June period. The maximum flow is

attained either in August or in September. After September, there is a steady fall in the flow.

The river, thus, has a monsoon regime during the rainy season.

The discharge is the volume of water flowing in a river measured over time. It is measured either in

cusecs (cubic feet per second) or cumecs (cubic meters per second)

The Godavari has the minimum discharge in May and the maximum in July-August.

After August, there is a sharp fall in water flow.

The mean maximum discharge of the Godavari at Polavaram is 3,200 cusecs while the mean

minimum flow is only 50 cusecs.

PROJECTS:

Periyar Diversion Scheme

Indira Gandhi Canal Project

Kurnool-Cuddapah Canal

Beas-Satluj Link Canal

Ganga-Kaveri Link Canal

REASONS:

(i) No availability in sufficient quantity

(ii) River water pollution

(iii) Load of silt in the river water

(iv) Uneven seasonal flow of water

(v) River water disputes between states

(vi) Shrinking of channels due to the extension of settlements towards the thalweg.

Chapter: WATER RESOURCES

India accounts for about 2.45 per cent of world’s surface area, 4 per cent of the world’s

water resources and about 16 per cent of world’s population.

o The total water available from precipitation in the country in a year is about 4,000

cubic km.

o The availability from surface water and replenishable groundwater is 1,869 cubic

km.

o Out of this only 60 per cent can be put to beneficial uses.

o Thus, the total utilisable water resource in the country is only 1,122 cubic km

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Precipitation is relatively high in the catchment areas of the Ganga, the Brahmaputra and the Barak

rivers, these rivers.

The level of groundwater utilisation is relatively high in the river basins lying in north-

western region and parts of south India.

o The groundwater utilisation is very high in the states of Punjab, Haryana, Rajasthan,

and Tamil Nadu. However, there are States like Chhattisgarh, Orissa, Kerala, etc.,

which utilise only a small proportion of their groundwater potentials

o States like Gujarat, Uttar Pradesh, Bihar, Tripura and Maharashtra are utilising their

ground water resources at a moderate rate.

o The States like Kerala, Orissa and West Bengal have vast surface water resources in

these lagoons and lakes. Although, water is generally brackish in these water-bodies,

it is used for fishing and irrigating certain varieties of paddy crops, coconut, etc.

Water Demand and Utilisation

Development of irrigation to increase agricultural production has been assigned a very high

priority in the Five Year Plans, and multipurpose river valleys projects like the Bhakra-

Nangal, Hirakud, Damodar Valley, Nagarjuna Sagar, Indira Gandhi Canal Project, etc. have

been taken up.

The large tracts of the country are deficient in rainfall and are drought prone. North-western

India and Deccan plateau constitute such areas. Winter and summer seasons are more or

less dry in most part of the country.

In fact, over withdrawals in some states like Rajasthan, and Maharashtra has increased

fluoride concentration in ground-water, and this practice has led to increase in

concentration of arsenic in parts of West Bengal and Bihar

The Ganga and the Yamuna are the two highly polluted rivers in the country

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Water Conservation and Management

There is need to encourage watershed development, rainwater harvesting, water recycling and

reuse, and conjunctive use of water for sustaining water supply in long run.

The major rivers of the country generally retain better water quality in less densely

populated upper stretches in hilly areas.

In plains, river water is used intensively for irrigation, drinking, domestic and industrial

purposes. The drains carrying agricultural (fertilisers and insecticides), domestic (solid and

liquid wastes), and industrial effluents join the rivers.

The concentration of pollutants in rivers especially remains very high during the summer

season when flow of water is low

The Central Pollution Control Board (CPCB) in collaboration with State Pollution Control Boards has

been monitoring water quality of national aquatic resources at 507 stations.

These stations show that organic and bacterial contamination continues to be the main

source of pollution in rivers.

The Yamuna River is the most polluted river in the country between Delhi and Etawah. Other

severely polluted rivers are: the Sabarmati at Ahmedabad, the Gomti at Lucknow, the Kali,

the Adyar, the Cooum (entire stretches), the Vaigai at Madurai and the Musi of Hyderabad

and the Ganga at Kanpur and Varanasi

Groundwater pollution has occurred due to high concentrations of heavy/toxic metals,

fluoride and nitrates at different parts of the country

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The legislative provisions such as the Water (Prevention and Control of Pollution) Act 1974

and Environment Protection Act 1986 have not been implemented effectively. The result is

that in 1997 The Water Cess Act, 1977, meant to reduce pollution has also made marginal

impacts.

The public awareness and action can be very effective in reducing the pollutants from

agricultural activities, domestic and industrial discharges

Watershed management basically refers to efficient management and conservation of surface and

groundwater resources.

In broad sense watershed management includes conservation, regeneration and judicious

use of all resources – natural (like land, water, plants and animals) and human with in a

watershed.

Watershed management aims at bringing about balance between natural resources on the

one hand and society on the other.

The Central and State Governments have initiated many watershed developments. Some of these

are being implemented by nongovernmental organisations also.

Haryali is a watershed development project sponsored by the Central Government which

aims at enabling the rural population to conserve water for drinking, irrigation, fisheries and

afforestation.

Neeru-Meeru(Water and You) programme (in Andhra Pradesh) and Arvary Pani Sansad (in

Alwar, Rajasthan) have taken up constructions of various water-harvesting structures such

as percolation tanks, dug out ponds (Johad), check dams, etc. through people’s participation.

Tamil Nadu has made water harvesting structures in the houses compulsory.

Rainwater Harvesting

Rainwater harvesting increases water availability, checks the declining ground water table,

improves the quality of groundwater through dilution of contaminants like fluoride and

nitrates, prevents soil erosion, and flooding and arrests salt water intrusion in coastal areas

if used to recharge aquifers

Apart from the above mentioned factors, the issue desalinisation of water particularly in

coastal areas and brackish water in arid and semi-arid areas, transfer of water from water

surplus areas to water deficit areas through inter linking of rivers can be important remedies

for solving water problem in India