River Noyyal origin and its tributaries
The Noyyal River originates from Western Ghats.
The main rivers which make up the Noyyal river are Periyar, Sadiyar and Kanchimanadhi. The rivers Periyar and Sadiyar, both originate from South-West hills of the horse-shoe shaped mountains in the west of Coimbatore and joins at Sadivayal to form Chinnar.
The river Anaiyar, originates from the central portion of the hills and also carries the Siruvani water transported through the tunnel near Mylone Bungalow to the Treatment Plant. Siruvani water is being diverted from Anaiyar river through a sluice just 100meters west of the treatment plant. The Anaiyar river continues and joins with river Periyar (Kovai Kutralam.)
Finally at Solaipadugai, Chinnar & Periyar confluences. This confluence takes place adjacent to the reserve forest and the Kanchimanadhi joins with Periyar at Kooduthurai in Alandurai Village.
Streams connected to River Noyyal –
In addition to the above said major tributaries, there are about 36 streams/rivulets which strengthens the River Noyyal from either side, starting from the origin, all the way up to Coimbatore. Out of the 36, 24 streams/rivulets originates from Southern Hills, and flows from South to North to the River Noyyal and the remaining 12 streams/rivulets originates from Northern Hills flows from North to South to join with the river. The average length of each stream range from 7 to 12 kilometers.
Present conditions of the streams/rivulets:
Few decades ago more than 50% of the streams were perennial, and the balance is seasonal during monsoon period. As on date, only Masaorambu and Mundandurai streams are observed with water flow during ten months. All other streams are narrowed down and encroached by the farmers with agriculture fields on both sides of the stream. Many streams are used as cart tracts and motor-able roads.
Siruthuli is aiming to trace out the original shape of the streams and rejuvenate them to the maximum possible extent in order to give strength back to the river Noyyal. At present, Nandangarai stream has been surveyed with digital theodolite and interpretation of data is in progress in order to analyse the causes for dying of the streams, and find ways to rectify it.