Vellar is a river which originates in the Shevaroy Hills and runs through the districts of Salem, Perambalur and Cuddalore in the northern part of the Indian state of Tamil Nadu before draining into the Bay of Bengal near Parangipettai.
The total length of the Vellar river is about 150 km. The total area of the basin is 7520.87Sq. km. The Vellar river basin is located in the Northern part of Tamil Nadu State in South India, between the latitudes 11° 13'N - 12 00' N and longitude 78° 13'E - 79° 47 E. This basin is in between the Ponnaiar, Paravanar and Cauvery river basins. The terrain lying in the Kalrayan hills, Attur Taluk of Salem District is drained by river upper velar, Vasis ta Nadhi known as Upper Vellar joined with to form the Vellar in the Perambalur Taluk of Permabalur District.
The river Vellar is having 6 tributaries. They are
A portion of Dharmapuri, Salem, Namakkal, Perambalur, Trichy, Villupuram and Cuddalore districts fall within the Vellar river basin. Manimukthanadhi, which is the major tributary, also originates from Kalrayan hills in Villupuram district, traverses about 111 km and joins Vellar near Srimushnam in Chidambararm taluk of Cuddalore District. Upper Vellar drains the water from the southern slopes of the Kalrayan hills on the northern boundary of Attur Taluk of Salem district. It originates at an altitude of 1266m about mean sea level. At its starting point, it is known as Anaimaduvu River and flows southwards for 23 km and then south -east wards. One reservoir constructed across Anaimaduvu River is called Anaimaduvu reservoir. Just three kilometers below this point another tributary known as Thumbal River, formed by two drainages viz., Karyakoil river and Ammapalayam river flowing southwards from Kottaipatti pass on the Kalrayan hills, joins on the left flank. Another stream called Periyar ori ginating in Jalluthu Reserve forest 'just 8 km east of Salem taluk joins this stream. As Periyar River approaches Salem - Attur road it bends eastwards and receives on the south, the Singipuram River. Vasistanadi then flows towards southeast for about 26 km along with boundary between Attur and Perambalur Taluk of Perambalur district on the one aide and Vridhachalam taluk of Cuddalore district on the other. Near Peraiyur in the Perambalur taluk, it is joined by Swetanadhi 4 km to the west of the Chennai - Trichy National Highway near Tholudur in Cuddalore district. In the reach between the confluence points of Singipuram and Swetanadhi with Vasistanadhi, the tributaries Kallar and Saval Odai join the main rive: on the left flank and Chittar, Koraiyar, Manjani Odai and Ellar Odai on the flank join the Vasistanadhi. The drainage area up to the confluence with the Swetanadhi is 1772 km2. An area of l0572.00 hectares is irrigated through 70 tanks and 79 anicuts. Vellar basin comprises the sub basins of Vasistanadhi, Swedhanadhi, Gomuki and Perambalur Minor Basin. This Vellar is having 6 Tributaries. They are 1.Vasistanadhi,2.Swedhanadhi,3.Kallar 4.Chinnar, 5.Manimukthanadhi, 7.Gomuki. The total length of the river is 150 km. SUB BASIN: Vasistanadhi is one of the sub basins in Vellar B asin. This Vasistanadhi sub basin comprises the parts of Attur, Salem, Rasipuram and Uthangarai revenue taluks in Salem district, Veppanthattai, Kunnam taluks in Perambalur district and Viruthachalam, Thittakudi taluks in Cuddalore district. Vasistanadhi originates from southern slopes of Kalvarayan hills on the northern boundary of Attur taluk of Salem district. The initial stretch which is flowing up to the confluence point of Kariakoil is called as Ammapalayam or Anaimaduvu River and beyond that it is ca lled as Tumbal River. Another small tributary which is called as Periyar River, originates in Vellagoundan Village of Salem District. Periyar and Tumbal River confluence at Periyakrishnapuram village in Attur taluk, below which it is called as Vasistanadhi Vasistanadhi joins with Swedha River at 4 km west of Chennai -Dindigul NH 45 near Peraiyur in Perambalur taluk. Beyond this confluence point, the river is called as Vellar River. Vellar River runs for a distance of 73 km in Perambalur, Cuddalore districts and then in falls into Bay of Bengal at Portonovo,now parangipettai near Chidambaram in Cuddalore district. The total length of Vasista River from the point of origin Kalvarayan hills to the point of confluence of Vasista with Swedha is 76.70 km. The total area of Vasista river sub basin is 1772Sq. km.