Rivers are the living entities in the lives of humans. Rivers in India owe a divine status in Indian history. Majority of the cities in India are located on the banks of the river. River water is not only used for religious purposes or to carry out day-to-day activities but it is also a means of livelihood to the people across the nation.
India is blessed with around 20 major river basins. The drainage system of India, that is, the rivers, is divided into two major groups-the Himalayan river system and the peninsular river system. The former is fed through glaciers and has water supply throughout the year, hence called perennial rivers. The latter however are seasonal in nature with rainfall being the primary source. In this article, we will take you on a tour and tell about the importance of the perennial rivers system which forms the backbone of the Indian Subcontinent.
The perennial river system is primarily fed through the Himalayan glaciers. The main Himalayan River systems are the Indus and the Ganga-Brahmaputra-Meghna system. These rivers are long and are joined by many tributaries. A river along with its tributaries forms a river system.
The Indus, which is one of the great rivers of the world, rises near Mansarovar in Tibet and flows through India, and thereafter through Pakistan, and finally falls in the Arabian Sea near Karachi. Its important tributaries flowing in Indian Territory are the Sutlej (originating in Tibet), the Beas, the Ravi, the Chenab, and the Jhelum. The Ganga-Brahmaputra-Meghna is another important system of which the principal sub-basins are those of Bhagirathi and the Alaknanda, which join at Devprayag to form the Ganga. It traverses through Uttarakhand, Uttar Pradesh, Bihar, and West Bengal. Below Rajmahal hills, the Bhagirathi, which used to be the main course in the past, takes off, while the Padma continues eastward and enters Bangladesh.
The Yamuna, the Ramganga, the Ghaghra, the Gandak, the Kosi, the Mahananda and the Son are the important tributaries of the Ganga. Rivers Chambal and Betwa are the important sub-tributaries, which join Yamuna before it meets the Ganga. The Padma and the Brahmaputra join inside Bangladesh, and continue to flow as the Padma or Ganga. The Brahmaputra rises in Tibet, where it is known as Tsangpo and runs a long distance till it crosses over into India in Arunachal Pradesh under the name of Dihang. Near Pasighat, the Debang and Lohit join the river Brahmaputra and the combined river runs all along the Assam valley. It crosses into Bangladesh downstream of Dhubri.
These rivers are antecedent in nature-that has maintained its original course and pattern despite the upliftment of Himalayas. E. Ahmad (1965 and 1971) has given his own interpretation of evolution of the Himalayan drainage. He believed that the Tethys remained as a basin of sedimentation from the Cambrian to the Eocene period but the major portion of the Himalayan region was occupied by the Gondwana landmass. During the first Himalayan upheaval in the Oligocene period, the major part of the Himalayan region was uplifted. The rivers that were draining into Tethys sea now started eroding the himalayas and thus marks the initiation of the Himalayan drainage.
The foredeep that was formed as a result of himalayan upliftment started filling through the sediments brought by these rivers and in time evolved as the Northern plains of India-one of the most fertile plains in the world. This also became the cradle of civilisations in north india throughout the history. These rivers are of economic, social and religious significance to the people of the Indian Subcontinent.
The growth of urban and industrial areas near these rivers has been very rapid in the past few decades. Together with big cities like Delhi, Kanpur etc. scarcity of water has also grown all over. The per capita availability of water has reduced from 5100 cu. meters in 1951 to 1545 cu. meters in 2011. This has put a considerable strain on these rivers. The level of pollution has increased considerably with industrial and household waste being dumped into the river.
Apart from that climate change has also altered the river regimes of the Himalayan Rivers. The climate change has led to the melting of the glaciers, which in the short run has increased the flow in these rivers. However, in the long run the availability of water in these rivers will be reduced due to depletion of glaciers which can be a threat to the river's sustainability.
Sand mining in the river beds has also been a cause of concern for the flow of these rivers. It affects the e-flow of the rivers along with stability of banks. This has led to constant shifting of rivers resulting in flooding.
Government is looking to create a National Water Grid by linking the peninsular rivers with the himalayan rivers through the National River Linking Project. However such inter basin transfer comes at an ecological cost. The natural flow of the rivers can get disturbed with both economic and ecological consequences. For now it is prudent to test this hypothesis within intra basin transfer and focus on alternatives such as water harvesting, cleaning of rivers, river restoration and watershed management. The Namami Gange Programme as an Integrated Conservation Mission for Ganga river is a good step in this regard which can be replicated to other systems in order to maintain the sustainability of the perennial rivers in the long run.
