PrepMaticTamil Nadu GK · Geography & nature
Dams in Tamil Nadu: river, district and key facts
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The Mettur Dam on the Cauvery in Salem district is the biggest reservoir in Tamil Nadu and the one most often asked in TNPSC papers. Other major dams are Bhavanisagar on the Bhavani, Vaigai on the Vaigai, Sathanur on the Thenpennai, and Papanasam on the Tamirabarani. Tamil Nadu also relies on thousands of village tanks and on ancient structures such as Kallanai and Veeranam, so questions mix colonial-era dams, Chola engineering and post-independence projects.
Major dams and reservoirs
| Dam or reservoir | River | District | Key fact |
|---|---|---|---|
| Mettur (Stanley Reservoir) | Cauvery | Salem | Completed in 1934; full level 120 ft; irrigates the delta; hydro-power stations |
| Bhavanisagar | Bhavani | Erode | Among the largest earthen dams in India; feeds the Lower Bhavani Project canal |
| Vaigai | Vaigai | Theni | Near Andipatti; completed in 1959; supplies Madurai and Dindigul |
| Sathanur | Thenpennai (Pennaiyar) | Tiruvannamalai | Completed in 1958; crocodile farm on the reservoir |
| Krishnagiri (KRP) | Thenpennai (Pennaiyar) | Krishnagiri | Irrigation for Krishnagiri and nearby areas |
| Amaravathi | Amaravathi | Tiruppur | Near Udumalpet; crocodile farm |
| Papanasam | Tamirabarani | Tirunelveli | Completed in 1944; hydro-electric station |
| Manimuthar | Manimuthar | Tirunelveli | Supports irrigation in Tirunelveli district; waterfall nearby |
| Pechiparai | Kodayar | Kanniyakumari | Completed in 1906; supplies the district's paddy fields |
| Aliyar | Aliyar | Coimbatore | Part of the Parambikulam-Aliyar Project; popular park at the foot |
| Poondi (Sathyamoorthy Sagar) | Kosasthalaiyar | Thiruvallur | A main source of Chennai's drinking water |
| Chembarambakkam | Adyar | Tiruvallur | Chennai reservoir on the city's western edge; source of the Adyar |
| Red Hills (Puzhal) | Kosasthalaiyar | Thiruvallur | Chennai reservoir |
| Veeranam | Fed by the Kollidam through the Vadavar canal | Cuddalore | Chola-era lake; a source for Chennai through a pipeline |
Some details above are approximate and can change when dams are rebuilt, renamed or re-surveyed; capacity and gross storage figures are best taken from the Water Resources Department.
Dams that are not in Tamil Nadu but matter to it
- Mullaiperiyar. Built across the Periyar between 1887 and 1895 under Colonel John Pennycuick, it stands in Kerala's Idukki district but is operated by Tamil Nadu under an 1886 lease. It sends water through a tunnel to the Vaigai basin and supports Theni, Madurai, Dindigul, Sivagangai and Ramanathapuram. The Supreme Court allowed the water level to be raised to 142 ft in 2014.
- Krishnaraja Sagara and Kabini. These Karnataka dams on the Cauvery and its tributary control inflow to Mettur.
- Parambikulam. Located in Kerala and part of the Parambikulam-Aliyar Project that shares water between Tamil Nadu and Kerala.
Old water structures
- Kallanai (Grand Anicut). On the Cauvery near Tiruchirappalli, built by Karikala Chola in the second century CE and one of the oldest water-regulation structures still in use. In the 1830s Arthur Cotton strengthened it and built the Lower Anicut on the Kollidam.
- Mukkombu (Upper Anicut). At the point where the Cauvery divides into the Cauvery and the Kollidam.
- Veeranam Lake. A large Chola-era tank in Cuddalore district, linked with the Kollidam by canal.
- Tank irrigation. Tamil Nadu's traditional irrigation relied heavily on tanks (eris). The Poondi and Red Hills tanks of Thiruvallur have been added to the Chennai supply system.
Short notes on most-asked items
- Mettur is the largest. It was built over the Cauvery in 1934 and named Stanley Reservoir after Sir George Stanley, Governor of Madras.
- Bhavanisagar. The earthen dam on the Bhavani river is among the largest of its kind in India.
- Pechiparai, completed in 1906, is the oldest of the dams in the table, apart from the ancient Veeranam lake.
- Crocodile farms at Sathanur and Amaravathi often appear as a "famous for" question.
- Hydro-power. Dams on the Cauvery, Bhavani, Kodayar and Tamirabarani host hydro stations; see power plants in Tamil Nadu.
How to revise
Make a three-column list of river, dam and district, then cover one column at a time. Pair each dam with a crop belt: Mettur with the Cauvery delta, Bhavanisagar with Erode and Tiruppur, Vaigai with Madurai, and Amaravathi with Karur. The major crops of Tamil Nadu page covers the crops, and the TNPSC geography guide covers the maps.
Frequently asked questions
Which is the biggest dam in Tamil Nadu?
Mettur Dam on the Cauvery in Salem district, completed in 1934, is the biggest reservoir in the state.
Which dam is called the Stanley Reservoir?
The Mettur Dam, named after Sir George Stanley, Governor of Madras when the dam was built.
Where is the Mullaiperiyar Dam and who runs it?
It is in Kerala's Idukki district, across the Periyar, but Tamil Nadu operates it under a 19th-century lease and uses its water in the Vaigai basin.
Which dam is on the Tamirabarani river?
Papanasam Dam in Tirunelveli district, completed in 1944, is the main one. Manimuthar is on a tributary system in the same district.
Official sources
- Government of Tamil Nadu portal for the Water Resources Department
- Central Water Commission
- India WRIS
Capacity and level figures change with surveys and rebuilding, so confirm any number with the Water Resources Department.
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