An underwater survey of the Mullaperiyar dam began on Sunday to collect data for technical analysis of the condition of the dam and the threat, if any, it poses.

The Empowered Committee on the Mullaperiyar dispute, appointed by the Supreme Court, has formed an expert team to conduct the survey. Kerala and Tamil Nadu are represented by their respective officials.

On Saturday, the scientists and engineers of the Centre for Soil and Materials Research Station had worked on the installation of the remote-operated underwater vehicle and other equipment, which reached the site on Friday.

A senior official of the Irrigation Department told The Hindu that the survey began in the morning, but voltage fluctuations hindered it. That might not create any problem in collecting the data, and the survey would last a minimum of 15 days.

The underwater pictures taken by the vehicle can be seen on monitors and the data will be provided for a technical study at the New Delhi laboratory of the research station.

P. Lathika, Chief Engineer, Irrigation Department, is representing the State. Additional Chief Secretary K. Jayakumar had directed her to be present at the survey site. Daniel George, Executive Engineer, was present on Saturday and Sunday, in addition to K. Kochappan, Director, Kerala Engineering Research Institute.

Tamil Nadu is being represented by a team of the operations and maintenance wing of its Public Works Department. Chandrasekharan, Executive Engineer, Kaveri Technical Cell, and Selvaraj, Chief Engineer, are in the survey team. Tight security has been provided and vehicles other than those of the officials are not being allowed through the Vandipperiyar-Vallakkadavu check-post.