The Ganga is the most important river system of India which drains over a quarter of the country’s surface area. Its flood plain is the granary house of the country supporting largest concentration of hu­man population. Its banks are dotted with important cities and its water is utilised for irrigation, hydel generation, industrial uses and drinking purposes.

The Ganga proper is formed by the conflu­ence of the Alaknanda and the Bhagirathi at Deva Prayag. The former consists of the Dhauli (rising in the Zanskar Range near Niti Pass) and the Vishnu- Ganga (originating from Mount Kamet 7756 m near Mana Pass) meeting at Joshimath or Vishnu Prayag.

The Pindar River rising from Nanda Devi and East Trisul (6803 m) joins the Alaknanda at Kama Prayag while the Mandakini or Kali Ganga meets it at Rudra Prayag. The source of Bhagirathi lies in the Gangotri glacier (25 km long) at a point called Gaumukh (3900 m). It is joined by the Jahnavi and forms adeep gorge near Bandarpunch.

The Ganga enters the Great Plains at Hardwar from where it flows towards south and south-east upto Allahabad. From Allahabad to Farakka its course is roughly easterly. Beyond Farakka, the mainstream of the Ganga flows east-south eastwards into Bangladesh and is called Padma. A bifurcation channel which is known as Bhagirathi-Hugli lies in India and flows in north-south direction to plunge into the Bay of Bengal near Sagar Island.

ADVERTISEMENTS:

The total length of the river is 2,525 km (UP 1,450 km, Bihar 445 km, West Bengal 520 km) with a drainage area of9,51,600 km2and average flow of45,904 crore m3 at Farakka (maximum 12,500 cum/sec; minimum 1,568 cum/sec.).

The Yamuna (length 1,384 km); drainage area 3, 59,000 km2) is the most important tributary of the Ganga. It rises on the western slopes of Bandarpunch in the Jamnotri glacier and runs almost parallel to Ganga and joins the latter at Prayag (Allahabad). In its upper reaches it is joined by the Tons, the Giri and Asan. Its tributaries include the Chambal, Betwa and Ken and Sind from the south and the Hindan, the Rind, the Sengar, the none, the Baruna and the Sasur Khaderi from the north. Geolo­gists believe that the Yamuna earlier flowed to the south and south-west in’o Rajasthan sharing its wa­ters with the Saraswati. Much of the water of the river is taken out in the western and eastern Yamuna and Agra canal for irrigation purposes. During the medieval period it was also an important means of transport which declined in recent times due to the development of railways and roads.

The Ghaghara (Karnali or Kauriala) rises in the glaciers of Mapchachungo, north-west ofTaklakot and collecting the waters of the Tila, the Seti and the Beri rivers carves out a deep 600m gorge at Shishapani. In the plains it is joined by the Sarda (Kali or Kaliganga) and flows south-eastward so as to meet the Ganga at Chapra. It has a total length of 1,080 km with a catchment area of 1, 27,500 km2, (55% lying in Nepal) and average annua’ water yield of 94,400 million m3.

The Gandak(Sadanira, Saligrami in Nepal, or Narayani in the plains) comprises two streams-the Kaligandak rising close to Photu Pass near Muktinath and the Trisulganga originating north of Gosainthan (8013 m). It cuts through the Mahabharat Range and covering a distance of 425 km joins the Ganga near Patna. Its total catchment area is 48,500 km2, of which 9,540 km2 lies in India, (average annual flow 52,200 million m).

ADVERTISEMENTS:

. The Kosi (Kausika) is the largest of the tribu­taries of the Ganga. It consists of 7 streams of which the main stream Arun (Phungchu in Tibet) rises to the north of Gosainthan. It has a total length of 730 km with a drainage area of 86,900 km (in India 21,500 km2) and average annual flow of 61,560 million m3.

The Kosi is notorious for its frequent and disatrous floods and shifting of courses. It is also called as ‘the sorrow of Bihar’. The river flowed by Purnea 200 years ago but its present course is about 160 km to the west of that place ravaging an area of about 10,500 km2. It now meets the Ganga 32 km west of Manihari (formerly near Manihari). A strik­ing feature of the river is that after the impetuosity of youth there is a sudden constriction of the advanced age, a sudden leap from the degraded to the aggraded stage with no graded interval (Singh, 1971, p. 196).

The Son (Swarna Nadi) is a large river (length 780 km; drainage area 71,900 km2) rising from the Amarkantak plateau not far off from the source of the Narmada. It first flows in north-westerly direc­tion and then takes a north-easterly course to meet the Ganga near Arrah (west of the Patna). In the plains of Bihar it has wide bed (4.8 km) and assumes huge size during rains. The confluence of the river with Ganga is gradually shifting towards west (in 1750 A.D. at Maner).

The Damodar River known as ‘the sorrow of Bengal’ rises in the hills of the Chotanagpur Plateau (1366 m). It joins the Hugli River 48 km south of Kolkata (length 541 km; drainage area 22,000 km average annual flow 12,210 million m3). The river has been tamed through DVC multi-purpose project which is providing significant contribution in the economic development of the area.

ADVERTISEMENTS:

Besides these major tributaries there are a number of minor tributaries which enrich the Ganga River during its eastward course. The Ganga Basin in India is shared by seven states of the country (U.P. 34.2%, M.P. 23.1%, Bihar 16.7%, Rajasthan 13%, West Bengal 8.3%, Haryana 4%, Himachal Pradesh 0.5% and Delhi 0.2%).