| Noyyal River | |
| Source1 Location: | Western Ghats in Tamil Nadu |
| Mouth Location: | Kaveri |
| Subdivision Type1: | Country |
| Subdivision Name1: | India |
| Length Km: | 180 |
| Basin Size Km2: | 3500 |
Noyyal is a - long seasonal river in Western Tamil Nadu, India. It is a tributary of the Kaveri river. The river rises in the Vellingiri hills in the Western Ghats, and flows westwards through the cities of Coimbatore, and Tirupur, before draining into the Kaveri at Noyyal in Karur district. The river basin covers an area of, which consists of of cultivable lands.
The river is seasonal, and dependent on the monsoon. An extensive tank system has been developed to store the river water and the overflow during monsoon. There are several check dams, and two larger dams - Aathupalayam and Orathuppalayam. Flowing through major urban areas, the river is highly polluted and faces significant ecological concern.
Noyyal is a sacred river for the Tamils. Its is referred to as Kanchimanadi in the Tamil text Perur Puranam. It got its name later in the 18th century CE. The Noyyal River and its interconnected tank and canal system is believed to have been built by the Chalukya Cholas, as a system of water transport, and storage.
The river rises in the Vellingiri hills in the Western Ghats, and flows westwards towards Coimbatore. After passing through Tirupur, and covering a total distance of, Noyyal joins the Kaveri river at Noyyal in Karur district. The river is seasonal and fed by monsoon. Tributaries and rivulets include Cheyyar, Kausika, and Periar, which join the river during its course.
From the source, the river valley consists of kankar soil for a stretch of to a depth of . It extends from the origin of the river to the Ukkadam Lake in Coimbatore. The fill absorbs water initially, and only when the absorption reaches a saturation point, the excess water flows downstream.
The Noyyal River system has an extensive network of canals, and tanks. Surplus water from the river spilled into the canals and were channeled to the tanks, preventing flooding, and was used to replenish the ground water and for utilisation later.[1] However, the system was neglected and the number of functional water bodies has reduced to eleven by 2003. This has had a profound effect on agriculture in the region.[2] [3]
There are two major dams - Orathuppalayam (near Chennimalai) and Aathupalayam (near Vellakoil), which were commissioned with the aim of irrigating about 20,000 acres of land in Tirupur and Karur districts. The Orathuppalayam dam has been decommissioned and acts as effluent storage tank. There are about 23 check dams.
Due to its course through urban areas, pollution has been a major concern. Textile units in Tiruppur release effluents into the river. Despite several litigation and court orders, which ordered the closure of such units, the river continues to be polluted. The Government of Tamil Nadu announced a project to prevent pollution in July 2018.[4]
