Rivers-Tamil Nadu

River Basin-17 

Rivers-Tamil Nadu

1. Rivers are the lifeline of Tamil Nadu.
2. Notable rivers include Cauvery, Palar, Ponnaiyar, Vaigai, and Thamirabarani.
3. Most rivers originate from the Western Ghats.
4. They flow towards the east and drain into the Bay of Bengal.
5. All rivers in the state are non-perennial except Thamirabarani.
6. Thamirabarani is a perennial river, fed by both the southwest and northeast monsoons.

Cauvery

1. The river Cauvery originates at Talacauvery in the Brahmagiri hills of Kodagu (Coorg) district of Karnataka in the Western Ghats.
2. The total length of the Cauvery river is 805 km, with about 416 km of its course in Tamil Nadu.
3. It serves as the boundary between Karnataka and Tamil Nadu for a distance of 64 km.
4. The river forms Hogenakkal waterfalls in Dharmapuri district.
5. Mettur Dam, also called the Stanley Reservoir, is located across this river in Salem district.
6. A tributary called Bhavani joins Cauvery on the right bank about 45 km from the Mettur Reservoir.
7. The river takes an easterly course to enter into the plains of Tamil Nadu.
8. Two more tributaries, Noyyal and Amaravathi, confluence the river on the right bank at Thirumukkudal, 10 km from Karur.
9. In this region, the river is wider and is called ‘Agandra Cauvery’.
10. In Tiruchirappalli district, the river branches into two parts:
    • The northern branch is called Coleroon or Kollidam.
    • The southern branch remains Cauvery.
11. From this point, the Cauvery delta begins.
12. After flowing for about 16 km, the two branches join again to form the ‘Srirangam Island’.
13. The Grand Anaicut, also called Kallanai, was built across the river Cauvery.
14. After Kallanai, the river breaks into a large number of distributaries, forming a network all over the delta.
15. The network of distributaries within the delta of Cauvery on the coast is called the ‘Garden of Southern India’.

Palar River

1. The Palar river rises beyond Talagavara village in the Kolar district of Karnataka.
2. The Palar drains an area of 17,871 sq.km, with nearly 57% in Tamil Nadu and the rest in Karnataka and Andhra Pradesh.
3. Major tributaries include Ponnai, Goundinya Nadhi, Malattar, Cheyyar, and Kiliyar.
4. The total length of the river is 348 km, with 222 km of its course in Tamil Nadu.
5. It flows through the districts of Vellore and Kancheepuram before entering the Bay of Bengal near Kuvattur.

ThenPennai

1. Then Pennaiyar (also known as Then Ponnaiyar) originates from the eastern slope of Nandi Durga hills in eastern Karnataka.
2. It drains an area of 16,019 sq.km, with nearly 77% in Tamil Nadu.
3. The river flows for a distance of 247 km in a southeasterly direction through the districts of Krishnagiri, Dharmapuri, Vellore, Tiruvannamalai, Cuddalore, and Villupuram.
4. It branches into two near Tirukoilur Anaicut: Gadilam and Ponnaiyar.
   • Gadilam joins the Bay of Bengal near Cuddalore.
   • Ponnaiyar joins the Bay of Bengal near the Union Territory of Puducherry.
5. Major tributaries include Chinnar, Markandanadhi, Vaniar, and Pambar.
6. Heavy rain at the river’s source can cause sudden but short-lived floods.
7. The river is extensively dammed for irrigation, especially in Tamil Nadu.
8. There are reservoirs at Krishnagiri and Sathanur across this river.

Vaigai River

1. Vaigai river rises from the eastern slopes of the Varusanadu hills of the Western Ghats in Tamil Nadu.
2. It drains an area of 7,741 sq.km, entirely within Tamil Nadu.
3. The river flows through the districts of Madurai, Sivaganga, and Ramanathapuram.
4. The total length of the river is 258 km.
5. It discharges its water into the Ramnad Big Tank and other small tanks.
6. Surplus water from these tanks is finally discharged into Palk Strait near Ramanathapuram.

Thamirabarani

1. The name Thamirabarani is derived from Thamiram (copper) and Varuni (streams of river).
2. The water of this river has a copper-like appearance due to the presence of dissolved suspended red soil.
3. It originates from a peak in the Pothigai hills on the Western Ghats above Papanasam in the Ambasamudram taluk.
4. The river courses through the districts of Tirunelveli and Thoothukudi.
5. It finally flows into the Bay of Bengal near Punnaikayal in Thoothukudi district.
6. The main tributaries are Karaiyar, Servalar, Manimuthar, Gadananathi, Pachaiyar, Chittar, and Ramanathi.
7. Thamirabarani is the only perennial river in South India.