The Victoria Dam, a landmark power station, underwent a major revamp after 30 years of its commissioning, reaching a milestone in the irrigation and hydroelectric power generation sector in the country.
The project comprised renovating and upgrading the control of spill gates from electric to electronics to ensure more integrity and reliability of its operations.
Work on the Rs. 1.4 billion initiative launched by the Sri Lanka Mahaweli Authority (SLMA) under the Dam Safety and Water Resource Planning Project (DSWRPP) commenced in 2014. The project was funded by the World Bank.
Director, Headwork of the Sri Lanka Mahaweli Authority (SLMA), S.R.K. Aruppola said reducing the risk and ensuring safety of the dam through new technology is pivotal.
“Reliability and integrity must be maintained at any cost to ensure the safety of the dam and its operation,” Aruppola said.
According to project engineers, surveying a dam is a tedious process which takes months. Therefore, going in for automation will make the task easier.
Construction of the 210 MW multi purpose arch dam, 209 km upstream of the mouth of the Mahaweli River began in 1978 and was completed in 1985.
The construction of the dam and the tunnel were completed by the British joint venture of Balfour Beatty and Edmund Nuttall while the construction of the power station was carried out by the Costain Group. The consultant engineers of the project was Sir Alexander Gibb and Partners.
Minor rehabilitation work of the dam structure and spillways had been carried out on and off, but there had not been a major renovation for over three decades, according to the project engineers.
“Failure of a dam structure or emergency spillover operation could lead to catastrophic damages to life, property and the economy as a whole which makes it all the more important to maintain the safety of the dam and efficiency of the irrigation system,” Aruppola said.
The need for urgent remedial measures and comprehensive rehabilitation of dams was felt after the collapse of the Kanthale dam in 1986.
A supervisory Control and Data Acquisition System was launched to control and provide real time status of the spill gates in the dam network of the Mahaweli basin.
“We have prepared an Emergency Action Plan for high risk dams. The plan has been given to the Disaster Management Centre and other relevant institutions for action,” Aruppola said.
DSWRPP also launched the Automated Geodetic Survey Monitoring System for the Victoria Dam which is the first double curved arch dam in the country, designed to stand hydrostatic pressure, which presses against the arch, compressing and strengthening the structure as it pushes into its foundation or abutments.
“Analyzing data, it has been observed that there are minor movements and curve changes of the Victoria dam which compelled the SLMA to introduce an advanced monitoring system for the dam. There is no apparent risk as result of these observed dam movements. But it is important to implement a better monitoring system of the dam and be ready for contingencies,” Aruppola said.
Global Navigation Satellite System or GSS Technology is used in the proposed monitoring solution. The information enables stakeholders to make efficient use of resources to address potential problems, improve safety decisions and ensure structural integrity.
Consultant, Victoria Project, E.M.S Bandara said 31 dams have been renovated under the phase two of the rehabilitation program.
Project engineers said that with the renovation, the safety of the dam could be maintained for a minimum of over two decades.
The revenue from power generation per annum from the Victoria Dam is around Rs. 4,000 million while around 1,000 million metre cubes of water is released by the dam for down stream irrigation.