It rises from the Vellingiri hills in the Western Ghats in Tamil Nadu, very closer in proximity to Kerala border, and flows through many villages and the cities of Coimbatore, and Tirupur.

The area is known for its scanty rainfall and the development of the Noyyal River Tanks System to hold any overflow from the rains plus the water of the Northeast and Southwest monsoon season was ecologically important.

Surplus water from the Noyyal river spilled into the canals and were channeled to the tanks, preventing unwanted flooding.

As city urbanized, the system was neglected and the number of functional water bodies drastically reduced until only eleven were left.

[citation needed] A critical issue is the pollution of the rivers Noyyal and Nallaru originating and flowing in the Kongu Nadu region.

The entire Orathuppalayam Dam has become a tank holding effluent and releases water after every rainfall, effectively polluting the down river villages in the Tirupur and Karur district.

[citation needed] However, from 2004 onwards, efforts by local volunteers organization Siruthuli have been trying to conserve the water resource.

After several petitions from 2003 to 2011, dying and bleaching units were ordered closed on the river until zero liquid discharge status was achieved.

[citation needed] The river has a valley fill (made of alluvial kankar soil) over a stretch of 25 km (16 mi) and a depth of 198 ft (60 m).