The Noyyal River rises from the Vellingiri hills in the Western Ghats in Tamil Nadu, southeastern India and drains into the Kaveri River.The river's basin is long and wide and covers a total area of . Cultivated land in the basin amounts to while the population density is 120 people per km² (311/mi²) in the countryside, and 1000 people per km² (2590/mi²) in the cities. 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. The long tributary of the Kaveri River filled 32 tanks. These interconnecting tanks held the water flowing from the Noyyal.