The Public Works Department engineers started the third phase of maintenance work in the century-old Periyar dam as per the permission given by the Supreme Court to Tamil Nadu.
Desilting of the 2.5 km long lead channel connecting the main dam and the head sluice at Thekkadi was taken up on Monday.
Cleaning of channel could be taken only when flow was low in it. Desilting the channel would increase its carrying capacity, officials added.
This channel was the only outlet to draw water from Periyar dam and distribute either through four giant pipes, each carrying capacity of 400 cusecs to generate power at Lower Camp or through Iraichal Bridge, an open channel supplying water for irrigation in Theni district.
In the first phase, concrete coating works of the baby dam was completed on October 9 and 10 and in the second phase, seepage holes in the main dam were cleaned using pressure spray method and other maintenance works.
The Tamil Nadu PWD could not undertake any maintenance work since 2001 owing to protests from Kerala Government.
After submission of report by the expert committee constituted by the SC Panel, the apex court advised Tamil Nadu to take up maintenance work in the presence of Kerala PWD officials.
