Chapter 3
Drainage
The term drainage describes the river system of an area.
The area drained by a single river system is called a drainage basin.
Any elevated area, such as a mountain or an upland, that separates two drainage basins is known
as a water divide.
The world's largest drainage basin is the Amazon River.
Drainage Systems in India
Himalayan Rivers Peninsular Rivers
Rivers originating from the Himalayas. Rivers originating from the Peninsular plateau.
Most of the Himalayan rivers are perennial, Most of the Peninsular rivers are seasonal, as
which means they have water throughout the their flow is dependent on rainfall.
year.
They receive water from rain as well as from The flow of these rivers is dependent on rain.
melted snow from lofty mountains.
The two main Himalayan rivers, the Ganga and Most of the rivers of Peninsular India originate
the Brahmaputra originate from the north of the in the Western Ghats and flow towards the Bay
mountain of Bengal.
ranges.
They have cut through the mountains making Peninsular rivers usually do not form gorges.
gorges.
The Himalayan rivers have long courses from The Peninsular rivers have shorter and
their source to the sea. shallower courses as compared to the
Himalayan rivers.
They perform intensive erosional activity in their They do not perform intensive erosional
upper courses and carry huge loads of silt and activities.
sand.
In the middle and the lower courses, these rivers Narmada and Tapi flow towards the west and
form meanders and oxbow lakes. They also form estuaries.
form deltas.
Ex- Ganga, Brahmapotra, Indus. Ex- Narmada, Godavari, Krishna, Kaveri.
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.
Several tributaries, the Zaskar, the Nubra, the Shyok, and the Hunza, join it in the Kashmir region.
Further flowing through Baltistan and Gilgit, Indus is joined by the Satluj, the Beas, the Ravi, the
Chenab, and the Jhelum near Mithankot in Pakistan.
Beyond this, the Indus flows southwards and eventually drains into the Arabian Sea, east of
Karachi.
With a total length of 2900 km, the Indus is one of the longest rivers in 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 is in Pakistan.
According to the regulations of the Indus Water Treaty (1960), India can use only 20 percent of the
total water carried by the Indus River system. This water is used for irrigation in Punjab, Haryana,
and the southern and western parts of Rajasthan.
The Ganga River System
The headwaters of the Ganga are Bhagirathi, which is fed by the Gangotri Glacier and Alaknanda.
They are both joined by each other at Devaprayag in Uttarakhand.
At Haridwar, the Ganga emerges from the mountains onto the plains.
The Ganga is joined by many tributaries.
Its Himalayan tributaries are the Yamuna, the Ghaghara, the Gandak, and the Kosi.
The river Yamuna rises from the Yamunotri Glacier in the Himalayas. It flows parallel to the Ganga
and meets the Ganga at Allahabad.
The Ghaghara, the Gandak, and the Kosi rise in the Nepal Himalayas. They cause floods in the
Northern Plains almost every year.
Its peninsular tributaries are the Chambal, the Betwa, and the Son.
These rise from semi-arid areas and have shorter courses. So, they do not carry much water in
them.
The Ganga flows eastwards till Farakka in West Bengal. This is the easternmost point of the Ganga
delta.
The river is divided here into:
The Bhagirathi-Hooghly (a distributary) flows southwards and drains into the Bay of Bengal.
The mainstream flows southwards into Bangladesh where it is joined by the Brahmaputra and forms
Meghna, and flows into the Bay of Bengal.
The delta formed when the Ganga and the Brahmaputra flow into the Bay of Bengal 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 the Royal Bengal tiger.
The length of the Ganga is over 2500 km.
Ambala is located on the water divide between the Indus and the Ganga river systems.
The plains from Ambala to the Sunderban stretch over nearly 1800 km, but the fall in its slope is
hardly 300 meters.
Drainage
The term drainage describes the river system of an area.
The area drained by a single river system is called a drainage basin.
Any elevated area, such as a mountain or an upland, that separates two drainage basins is known
as a water divide.
The world's largest drainage basin is the Amazon River.
Drainage Systems in India
Himalayan Rivers Peninsular Rivers
Rivers originating from the Himalayas. Rivers originating from the Peninsular plateau.
Most of the Himalayan rivers are perennial, Most of the Peninsular rivers are seasonal, as
which means they have water throughout the their flow is dependent on rainfall.
year.
They receive water from rain as well as from The flow of these rivers is dependent on rain.
melted snow from lofty mountains.
The two main Himalayan rivers, the Ganga and Most of the rivers of Peninsular India originate
the Brahmaputra originate from the north of the in the Western Ghats and flow towards the Bay
mountain of Bengal.
ranges.
They have cut through the mountains making Peninsular rivers usually do not form gorges.
gorges.
The Himalayan rivers have long courses from The Peninsular rivers have shorter and
their source to the sea. shallower courses as compared to the
Himalayan rivers.
They perform intensive erosional activity in their They do not perform intensive erosional
upper courses and carry huge loads of silt and activities.
sand.
In the middle and the lower courses, these rivers Narmada and Tapi flow towards the west and
form meanders and oxbow lakes. They also form estuaries.
form deltas.
Ex- Ganga, Brahmapotra, Indus. Ex- Narmada, Godavari, Krishna, Kaveri.
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.
Several tributaries, the Zaskar, the Nubra, the Shyok, and the Hunza, join it in the Kashmir region.
Further flowing through Baltistan and Gilgit, Indus is joined by the Satluj, the Beas, the Ravi, the
Chenab, and the Jhelum near Mithankot in Pakistan.
Beyond this, the Indus flows southwards and eventually drains into the Arabian Sea, east of
Karachi.
With a total length of 2900 km, the Indus is one of the longest rivers in 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 is in Pakistan.
According to the regulations of the Indus Water Treaty (1960), India can use only 20 percent of the
total water carried by the Indus River system. This water is used for irrigation in Punjab, Haryana,
and the southern and western parts of Rajasthan.
The Ganga River System
The headwaters of the Ganga are Bhagirathi, which is fed by the Gangotri Glacier and Alaknanda.
They are both joined by each other at Devaprayag in Uttarakhand.
At Haridwar, the Ganga emerges from the mountains onto the plains.
The Ganga is joined by many tributaries.
Its Himalayan tributaries are the Yamuna, the Ghaghara, the Gandak, and the Kosi.
The river Yamuna rises from the Yamunotri Glacier in the Himalayas. It flows parallel to the Ganga
and meets the Ganga at Allahabad.
The Ghaghara, the Gandak, and the Kosi rise in the Nepal Himalayas. They cause floods in the
Northern Plains almost every year.
Its peninsular tributaries are the Chambal, the Betwa, and the Son.
These rise from semi-arid areas and have shorter courses. So, they do not carry much water in
them.
The Ganga flows eastwards till Farakka in West Bengal. This is the easternmost point of the Ganga
delta.
The river is divided here into:
The Bhagirathi-Hooghly (a distributary) flows southwards and drains into the Bay of Bengal.
The mainstream flows southwards into Bangladesh where it is joined by the Brahmaputra and forms
Meghna, and flows into the Bay of Bengal.
The delta formed when the Ganga and the Brahmaputra flow into the Bay of Bengal 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 the Royal Bengal tiger.
The length of the Ganga is over 2500 km.
Ambala is located on the water divide between the Indus and the Ganga river systems.
The plains from Ambala to the Sunderban stretch over nearly 1800 km, but the fall in its slope is
hardly 300 meters.
