The Himalayan drainage system has evolved through a long geological history. It mainly includes Ganga, Indus and Brahmaputra river basins. Since these are fed both by melting of snow and precipitation, rivers of this system are perennial.
- The rivers of Indus system follow northwesterly courses.
- The rivers of Ganges-Brahmaputra systems generally take easterly courses.
The Himalayas are drained by 19 major rivers, of which the Indus and the Brahmaputra are the largest. The major Himalayan rivers rise north of the mountain ranges and flow through deep gorges that generally reflect some geologic structural
control, such as a fault line.
- In mountainous courses, these rivers follow highly tortous courses and form deep gorges, V-shaped valleys, rapids and waterfalls.
- In plains, they form depositional features like flat valleys, ox-bow lakes, flood plains, braided channels, and deltas near the river mouth. Here they show strong meandering tendency and shift their courses frequently. For example, River Kosi, also know as the ‘sorrow of Bihar’, has been notorious for frequently changing its course. The Kosi brings huge quantity of sediments from its upper reaches and deposits it in the plains. The course gets blocked, and consequently, the river changes its course.
To the north of India, the Karakoram Range forms the great water divide, shutting off the Indus system from the rivers of Central Asia. The counterpart of that divide on the east is formed by the Kailas Range and its eastward continuation which
prevent the Brahmaputra from draining the area to the north.
The Himalayas are drained by 19 major rivers:
- Indus system (5): Jhelum, Chenab, Ravi, Beas, and Sutlej
- Ganges system (9): Ganges, Yamuna, Ramganga, Kali (Kali Gandak), Karnali, Rapti, Gandak, Baghmati, and Kosi rivers
- Brahmaputra system (3): Tista, Raidak, and Manas
Evolution of Himalayan Drainage
There are many opinions about the evolution of the Himalayan rivers. However, geologists believe that a mighty river called
Shiwalik or Indo-Brahma traversed the entire longitudinal extent of the Himalaya from Assam to Punjab and onwards to Sind. It finally discharged into the Gulf of Sind near lower Punjab during the Miocene period some 5-24 million years ago.
This viewpoint is supported by:
- remarkable continuity of the Shiwalik
- lacustrine origin of the Shiwalik
- alluvial deposits consisting of sands, silt, clay, boulders and conglomerates
In due course of time Indo–Brahma river was dismembered into three main
- Indus and its five tributaries in the western part
- Ganga and its Himalayan tributaries in the central part
- stretch of the Brahmaputra in Assam and its Himalayan tributaries in the eastern part.
- 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.
- Downthrusting 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 System
It is one of the largest river basins of the world,
covering an area of 11,65,000 sq. km (in India
it is 321, 289 sq. km and a total length of 2,880
km (in India 1,114 km).
- It originates from a glacier near Bokhar Chu in the Tibetan region at an altitude of 4,164 m in the Kailash Mountain range.
- After flowing in the northwest direction between the Ladakh and Zaskar ranges, it passes through Ladakh and Baltistan. It cuts across the Ladakh range, forming a spectacular gorge near Gilgit in Jammu and Kashmir.
- It flows in India only through Jammu and Kashmir.
- It enters into Pakistan near Chilas in the Dardistan region.
- Then it flows southward and receives ‘Panjnad’ a little above Mithankot. The Panjnad is the name given to the five rivers of Punjab, namely the Satluj, the Beas, the Ravi, the Chenab and the Jhelum.
- It finally discharges into the Arabian Sea, east of Karachi.
- Himalayan tributaries: Shyok, Gilgit, Zaskar, Hunza, Nubra, Shigar, Gasting and Dras.
- It finally emerges out of the hills near Attock where it receives the Kabul river on its right bank.
- Rivers from Sulaiman ranges: Khurram, Tochi, Gomal, Viboa and Sangar. These all rivers join Indus on the right bank.
- Panjnad: The Indus receives ‘Panjnad’ a little above Mithankot. The Panjnad is the name given to the five rivers of Punjab, namely Satluj, Beas, Ravi, Chenab and Jhelum.
- The Indus also known as the Sindhu, is the westernmost of the Himalayan rivers in India.
- In Tibet, it is known as ‘Singi Khamban' or Lion’s mouth.
- It rises from a spring at Verinag situated
at the foot of the Pir Panjal in the south-eastern
part of the valley of Kashmir.
- It flows through Srinagar and Wular lake before entering Pakistan through a deep narrow gorge.
- It joins
the Chenab near Jhang in Pakistan.
- It is the largest tributary of Indus.
- The river flows for 1,180 km in India before entering into Pakistan.
- It is formed by two streams, the Chandra and the Bhaga. Hence, it is also known as Chandrabhaga.
- Chandra and Bhaga join at Tandi near Keylong in Himachal Pradesh.
- It rises west of the Rohtang pass in Kullu hills of Himachal Pradesh and flows through the Chamba valley of the state.
- It drains southeastern part of the Pir Panjal and the Dhauladhar ranges.
- It enters Pakistan and join Chenab near Sarai Sidhu.
- It originates from the Beas Kund near Rohtang Pass at an elevation of 4,000 m above the mean sea level.
- It flows through the Kullu valley and forms gorges at Kati and Largi in the Dhaoladhar range.
- It enters the Punjab plains where it meets the Satluj near Harike.
- It originates in the ‘Raksas tal’ near Mansarovar at an altitude of 4,555 m in Tibet.
- In Tibet, it is known as Langchen Khambab.
- It flows almost parallel to the Indus for about 400 km before entering India, and comes out of a gorge at Rupar.
- It passes through the Shipki La on the Himalayan ranges and enters the Punjab plains.
- It is an antecedent river.
- It is a very important tributary as it feeds the canal system of the Bhakra Nangal project.
The Ganga System
The Ganga is the most important river of India both from the point of view of its basin and cultural significance. It has a length of 2,525 km. It is shared by Uttarakhand (110 km) and Uttar Pradesh (1,450 km), Bihar (445 km) and West Bengal (520 km). The Ganga basin covers about 8.6 lakh sq. km area in India alone. 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.
- It rises in the Gangotri glacier near Gaumukh (3,900 m) as Bhagirathi in the Uttarkashi district of Uttarakhand.
- It cuts through the Central and Lesser Himalayas in narrow gorges.
- At Devprayag, the Bhagirathi meets the Alaknanda; hereafter, it is known as the Ganga. (The five confluences, known as the Panch Prayag, are all along the Alaknanda.)
- The Alaknanda has its source in the Satopanth glacier above Badrinath. The Alaknanda consists of the Dhauli and the Vishnu Ganga which meet at Joshimath or Vishnu Prayag. The other tributaries of Alaknanda such as the Pindar joins it at Karna Prayag while Mandakini or Kali Ganga meets it at Rudra Prayag.
- The Ganga enters the plains at Haridwar.
- Then it flows first to the south, then to the south-east and east before splitting into two distributaries, namely the Bhagirathi and the Padma.
- The river finally discharges itself into the Bay of Bengal near the Sagar Island.
- Left bank tributaries: Ramganga, Gomati, Ghaghara, Gandak, Kosi and Mahananda.
- Right bank tributary: Son
- It is called as Bhagirathi in Uttarakhand where it rises in Gangotri glacier.
- It is known as Ganga after Devprayag, where it meets Alaknanda.
- After entering Bangaladesh, the main branch of the Ganges is known as the Padma.
- It is known as Meghna when Padma joins Meghna (the second largest distributary of the Brahmaputra).
- It is the western most and the longest tributary of the Ganga and joins the Ganga at Prayag (Allahabad).
- It has its source in Yamunotri glacier on the western slopes of Banderpunch range (6,316 km).
- Right bank tributaries: Chambal, Sind, Betwa and Ken. These rivers originate from the Peninsular plateau.
- Left bank tributaries: Hindan, Rind, Sengar, Varuna, etc.
- Much of its water feeds western and eastern Yamuna and Agra canals for irrigation purposes.
- It rises near Mhow in Malwa plateau of Madhya Pradesh.
- It flows northwards through a gorge up wards of Kota in Rajasthan, where the Gandhisagar dam has been constructed.
- From Kota, it traverses down to Bundi, Sawai Madhopur and Dholpur, and finally joins the Yamuna.
- The Chambal is famous for its badland topography called the Chambal ravines.
- It comprises two streams, namely Kaligandak and Trishulganga.
- It rises in the Nepal Himalayas between the Dhaulagiri and Mount Everest and drains the central part of Nepal.
- It enters the Ganga plain in Champaran district of Bihar and joins the Ganga at Sonpur near Patna.
- It originates in the glaciers of Mapchachungo.
- After collecting the waters of its tributaries – Tila, Seti and Beri, it comes out of the mountain, cutting a deep gorge at Shishapani.
- The river Sarda (Kali or Kali Ganga) joins it in the plain before it finally meets the Ganga at Chhapra.
- It is an antecedent river with its source to the north of Mount Everest in Tibet, where its main stream Arun rises.
- After crossing the Central Himalayas in Nepal, it is joined by Son Kosi from the West and the Tamur Kosi from the east. It forms Sapt Kosi after uniting with the river Arun.
- It is comparatively a small river rising in the Garhwal hills near Gairsain.
- It changes its course to the southwest direction after crossing the Shiwalik.
- It enters into the plains of Uttar Pradesh near Najibabad.
- Finally, it joins the Ganga near Kannauj.
- It occupies the eastern margins of the Chotanagpur Plateau where it flows through a rift valley and finally joins the Hugli.
- The Barakar is its main tributary.
- Once known as the ‘sorrow of Bengal’, the Damodar has been now tamed by the Damodar Valley corporation, a multipurpose project.
Sarda or Saryu
- It rises in the Milam glacier in the Nepal Himalayas where it is known as the Goriganga.
- Along the Indo-Nepal border, it is called Kali or Chauk, where it joins the Ghaghara.
- It rises in the Darjiling hills.
- It joins the Ganga as its last left bank tributary in West Bengal.
- It is large south bank tributary of the Ganga.
- It originates in the Amarkantak plateau.
- After forming a series of waterfalls at the edge of the plateau, it reaches Arrah, west of Patna, to join the Ganga.
The Brahmaputra System
The Brahmaputra, one of the largest rivers of the world.
- It has its origin in the Chemayungdung glacier of the Kailash range near the Mansarovar lake. From here, it traverses eastward longitudinally for a distance of nearly 1,200 km in a dry and flat region of southern Tibet, where it is known as the Tsangpo, which means ‘the purifier'. The Rango Tsangpo is the major right bank tributary of this river in Tibet.
- It emerges as a turbulent and dynamic river after carving out a deep gorge in the Central Himalayas near Namcha Barwa (7,755 m). It emerges from the foothills under the name of Siang or Dihang.
- It enters India west of Sadiya town in Arunachal Pradesh.
- Flowing southwest, it receives its main left bank tributaries, viz., Dibang or Sikang and Lohit; thereafter, it is known as the Brahmaputra. Its major left bank tributaries are the Burhi Dihing and Dhansari (South).
- The important right bank tributaries are the Subansiri, Kameng, Manas and Sankosh. The Subansiri which has its origin in Tibet, is an antecedent river.
- The Brahmaputra enters into Bangladesh near Dhubri and flows southward. In Bangladesh, the Tista joins it on its right bank from where the river is known as the Jamuna. It finally merges with the river Padma, which falls in the Bay of Bengal.