In addition to irrigation, the Thirumoorthy Reservoir also stabilizes irrigation for the old ayacut of approximately 1,050 hectares under the Dhali system of Palar. A high-level canal, originating from the reservoir, supplies water to an additional 1,002 hectares of land.
The Thirumoorthy Reservoir is constructed across the River Palar, which originates from the northern slopes of the Anamalai Hills. The reservoir gets its name from the nearby Thirumoorthy Waterfall and Temple. It has a gross capacity of 1,935 million cubic feet (Mcft) and serves as a water source for irrigation purposes.
The Palar River has an old anicut called Dhali anicut located approximately 5 miles downstream from its origin. This anicut has open head channels and irrigates around 1,120 hectares of land, with direct irrigation covering 70 hectares and the remainder through a system of seven tanks.
The Thirumurthy Reservoir receives water not only from its own catchment but also from the Uppar Reservoir in the Anamalai Range. This water is diverted through the Sarkarpathy tunnel and the Contour Canal.
From the Thirumurthy Reservoir, two main irrigation canals branch out:
- Parambikulam Main Canal: This is the longest canal, spanning 125 kilometers, and serves as the primary irrigation canal under the Parambikulam Aliyar Project. It has an ayacut (cultivable command area) associated with it.
- Udumalpet Canal: This canal is 30.4 kilometers long and serves as a secondary irrigation canal.
This irrigation system plays a crucial role in supporting agriculture and ensuring water availability for the surrounding areas.