Rivers - Get Started
In India, rivers originate from the Himalayas, the plains and even from its deserts. While rivers are indispensable to the eco-cycle, they are vulnerable to several natural and manmade influences. India’s rivers are affected by erratic rainfall patterns, dumping of agricultural and industrial waste, sewage contamination, dams and artificial reservoirs. At the same time, water from rivers is required for the socio-economic growth of communities and industries. The challenge is to strike a balance between its equitable usage on the one hand and its replenishment and maintenance on the other. Are India’s rivers fighting a losing battle?
Frequently Asked Questions
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How do rivers originate?
Rivers originate mostly from watershed in mountains. Snowmelt and rain drops turn into rivulets on the mountains slopes. As many rivulets join, they gain speed to become mountain streams. As the streams descend, they join tributaries and flowing surface water that add to their volume and become rivers. As they leave the mountains, rivers slow and start to meander and braid, seeking the path of least resistance across widening valleys, and eventually flows into a lake, sea or ocean. Where the river is muddy and the land flat, the sediments laid down by the river may form a delta, splitting the river into a bird–foot of distributaries which discharge into the sea. The river’s estuary, the place where its sweet waters mix with the ocean’s salt, is one of the most biologically productive parts of the river – and of the ocean. Most of the world’s fish catch comes from species which are dependent for at least part of their life cycle on a nutrient–rich estuarine habitat
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Rivers can get contaminated due to various reasons and many have become scanty or dry. What are the ways to revive rivers?
- Dismantling: The complete dismantling of all physical barriers to stream flow is the only way to fully restore the natural flow of the river, including peak flows and seasonal flooding. This is the best way to restore fish passage and the transport of gravel and organic debris downstream. Dam removal is usually staged to avoid sudden release of the sediments that have accumulated behind the dam wall. This is the most costly (and rarest) restoration option.
- Partial Decommissioning: Some of the dam remains with this approach. Altering the dam structure will restore some flow and change the dam's original function.
- Modification: Various options have little or no impact on dam function. For example, the addition of fishladders can be used to improve fish access to spawning habitat above the dam without altering the function of the dam itself.
- Re-operation: Improving the release of water from dams usually allows the dam to continue with its original functions. Re-operation can improve fish survival downstream by releasing more water from the reservoir during critical times such as spawning season. While more effective management of dams can help to mitigate environmental impacts, it should be noted that many dams around the world presently lack the mechanisms needed to control water discharge.
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What role do rivers play in the eco-system?
A river is defined by a channel with permanently-flowing water while its drainage area or the area in which the river empties itself is known as a river basin.
There are seven basins in India and these include Ganga basin, Godavari basin, Indus basin, Krishna basin, Mahanadi basin, Narmada basin and Tapi basin. -
How does flooding impact on the river?
While floods denote misery for mankind, in the nature’s eco-system, it increases the fertility of the river. The more fertile a river, the more aquatic flora and fauna can survive and grow. Floods also wash dead brush and trees into the stream, providing habitat (structure) for many animals.
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What is the role of a river dam?
Nothing alters a river as totally as a dam. A reservoir is the antithesis of a river – the essence of a river is that it flows, the essence of a reservoir that it is still. A wild river is dynamic, forever changing – eroding its bed, depositing silt, seeking aa new course, bursting its banks, drying up. A dam is monumentally static, it tries to bring a river under control, to regulate its seasonal pattern of floods and low flows. A dam traps sediments and nutrients, alters the river’s temperature and chemistry, and upsets the geological processes of erosion and deposition through which the river sculpts the surrounding land.
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How many types of rivers are there in India?
- Himalayan rivers: Indus, Ganges and Brahmaputra.
- Interstate rivers falling in the Bay of Bengal: Subarnarekha, Brahmani, Mahaadi, Vamsadhara, Nagavati, Godavari, Krishna, Kaveri Penneru, Korthalaiyaar, Paalar, Ponnaiyaar.
- Interstate rivers falling in the Arabian sea: Sabarmati, Mahe, Narmada., Tapti, Purna, Mandavi, Upplayaar, Chiria, Chandragiri, Kariangode, Kuppam, Valapatam, Chaliyar, Bharatapuzha, Chalakudi River
- Desert rivers: Ghagar, Saraswati, Luni
- Other rivers falling in the Bay of Bengal: Burbabalang, Baitarni, Rishikulya, Sharada, Yeleru, Gundalakamma, Musi, Paleru, Muneru, Kunlenu, Swarnamukhi, Vellar, Vaiga, Chundar, Avaipar, Thamraparni
- Other rivers falling in the Arabian sea: Bhadar, Satrunji, Dhadar, Ambika, Vaitarna, Ulhas, Savitri, Kalinadi, Gangavati, Sharaavti, Netravati, Manjeswaram river, Mogral, Chittaripuzha, Nileswaram nadi, Kavvayipuzha, Pervampayaru, Mayyazhipuzha, Kuttiyadipuzha, Korapuzha, Kallayipuzha, Kadalundipuzha, Thirurpuzham, Keecheripuzha, Puzhaykalaaru, Karuvannurpuzha, Periyar, Muvattupuzhayaru, Meenachilaru, Manimalyaru, Pampanadi, Achchankovilaru, Pallichalaru, Kalladayaru, Iththikarayaru, Ayirupuzha, Vamanapuram Aru, Mamam Aru, Karamanayaru, Neyyar
- Small rivers flowing into foreign countries: Karnaphuli, Kaladan, Imphal, Tiksu.
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