• A drainage system is an integrated system of tributaries and a trunk stream which collects and drains surface water into the sea, lake or some other body of water.
• The total area drained by a river and its tributaries is known as a drainage basin.
• The drainage pattern of an area is the result of the geological structure of the Respective areas.
• The drainage system of India is broadly divided into two major groups on the basis of their location.
• They are Himalayan Rivers and the Peninsular Rivers.

Himalayan Rivers:

• These rivers are found in north India and Originate from Himalayas. So, they are also called as Himalayan Rivers. These are perennial rivers.

The Indus River System:

• The Indus River is one of the largest rivers of the world.
• It originates from the northern slope of the Kailash range in Tibet near Manasarovar Lake at an elevation of about 5,150 m.
• Its length Is about 2,880 km (Only 709 km is in India).
• The river has a total drainage area extending 11,65,500 sq km in which 321,289 sq. km areas Are drained in India.
• The river flows through the Ladakh and Zaskar ranges and creates deep Gorges.
• The river runs through Jammu and Kashmir, turns south near Chillar and enters Pakistan.
• Its major tributaries are Jhelum, Chenab (Largest tributary of Indus), Ravi, Beas and Sutlej.
• It enters into with the Arabian Sea.

The Ganga River System:

• The Ganga River system is the largest Drainage system of India.
• It extends over an area of 8,61,404 sq. km.
• The Ganga plain is the most Densely populated place in India and many towns are developed on the banks of this river.
• The river Ganga originates as Bhagirathi from the Gangotri Glacier in Uttar Khasi District of Uttarakhand state, at an elevation of 7,010 m.
• The length of the river Ganga is about 2,525 Km.
• Its major tributaries from the north are Gomti, Gandak, Kosi and Ghaghra and from South, Yamuna (largest tributary of Ganga), Son, Chambal etc.
• The river Ganga is known as the River Padma in Bangladesh.
• The combined River of Ganga and Brahmaputra creates the World’s largest delta known as Sundarbans in Bangladesh before joining the Bay of Bengal.

The Brahmaputra River System:

• The river Brahmaputra originates from the Chemayungdung Glacier of the Kailash Range to the east of Lake Manasarovar in Tibet at an elevation of about 5,150 m.
• The total area is about 5,80,000 sq. km but the drainage area found in India is 1,94,413 sq. km this river is Known as Tsangpo (Purifier) in Tibet.
• The Length of this river is about 2,900 km (900 km In India).
• It enters into India through a gorge in Arunachal Pradesh namely Dihang.
• It has many Tributaries.
• Tista, Manas, Barak, Subansiri are Some of them.
• This river is called as Jamuna in Bangladesh.
• After it joins with the river Ganga in Bangladesh, the river is called as Meghna.

Characteristics of Himalayan Rivers:

• Long and wide
• Perennial in nature
• Unsuitable for hydro power generation
• Middle and lower courses are navigable

Peninsular Rivers:

• The rivers in south India are called the Peninsular Rivers.
• Most of these rivers originate From the Western Ghats.
• These are seasonal Rivers (non–perennial).
• They have a large Seasonal fluctuation in volume of water as they are solely fed by rain.
• These rivers flow in valleys with steep gradients.
• Based on the direction of Flow, the peninsular rivers are divided into the
• West flowing rivers
• East flowing rivers

West Flowing Rivers:

• Narmada
• This river rises in Amarkantak Plateau in Madhya Pradesh at an elevation of about 1057 m and flows for a distance of about 1,312 km.
• It covers and area of 98,796 sq. km and forms 27 km long estuary before out falling into the Arabian Sea through the Gulf of Cambay.
• It is the largest among the west flowing rivers of Peninsular India.
• Its principal tributaries are Burhner, Halon, Heran, Banjar, Dudhi, Shakkar, Tawa, Barna and Kolar.
• Tapti
• The Tapti is one of the major rivers of Peninsular India with the length of about 724 Km.
• It covers an area of 65,145 sq km.
• Tapti River rises near Multai tank in the Betul district of Madhya Pradesh at an elevation of about 752 m.
• It is one of only the three rivers in Peninsular India that run from east to west – the others Being the Narmada and the Mahi.
• In Kerala – Mullaiperiyar and Bharathapuzha the west flowing rivers.
• The major Tributaries are Vaki, Gomai, Arunavati, Aner, Nesu, Buray, Panjhra and Bori.
• Its outfalls into the Arabian Sea through the Gulf of Cambay.

East Flowing Rivers:

• Mahanadi:
• The river Mahanadi originates near Sihawa in Raipur district of Chattisgarh and Flows through Odisha.
• Its length is 851 km.
• Seonath, Telen, Sandur and Ib are its major Tributaries.
• The main stream of Mahanadi gets Divided into several distributaries such as Paika, Birupa, Chitartala, Genguti and Nun.
• All these Distributaries form the Delta of Mahanadi Which is one of the largest deltas in India.
• The Mahanadi empties its water in Bay of Bengal.
• Godavari:
• Godavari is the longest river (1,465 Km) with an area of 3.13 lakh km2 Among the Peninsular rivers.
• It is also called Vridha Ganga.
• It originates in Nasik district of Maharashtra, a portion of Western Ghats.
• It flows through the states of Telangana and Andhra Pradesh Before joining Bay of Bengal.
• Purna, Penganga, Pranitha, Indravati, Tal and Salami are its major Tributaries.
• The river near Rajahmundry gets Divided into two Channels called Vasistha and Gautami and forms one of the largest deltas in India.
• Kolleru, a fresh water lake is located in the deltaic region of the Godavari.
• Krishna:
• The river Krishna originates from a spring at a place called Mahabaleshwar in the Western Ghats of Maharashtra.
• Its length is 1,400 km and an area of 2.58 lakh sq km.
• It is the second Longest Peninsular River Bhima, Peddavagu, Musi, Koyna and Thungabhadra are the major Tributaries of this river.
• It also flows through Andhra Pradesh and joins in Bay of Bengal, at Hamasaladeevi.
• Kaveri
• The river Kaveri originates at Talakaveri, Kudagu hills of Karnataka.
• Its length is 800 Km.
• The river kaveri is called Dhakshin Ganga or Ganga of south.
• In Karnataka the river Bifurcates twice, forming the sacred islands of Srirangapatnam and Sivasamudram.
• While Entering Tamil Nadu, the Kaveri continues through a series of twisted wild gorges until it Reaches Hogenakkal Falls and flows through a Straight, narrow gorge near Salem.
• The Kaveri Breaks at Srirangam Island with two channels, River Coleroon and Kaveri.
• At last, it empties Into the Bay of Bengal at Poompuhar.

Characteristics of South Indian Rivers:

• Originate from Western Ghats
• Short and narrow
• Non perennial in nature
• Suitable for hydro power generation
• Not useful for navigation