June 14, 2017 - With the completion of a cofferdam, Salini Impregilo has reached its first milestone in the construction of the Rogun hydroelectric dam in Tajikistan, an ambitious $3.9-billion project that will double the Central Asian country’s capacity to produce electricity.
Built with 2.7 million cubic metres of rockfill and 35,000 square metres of impervious membrane, the cofferdam’s role is to withstand the Vakhsh River during the high flow season and have it pass through two diversion tunnels on the left side of the valley through which the river courses in the Pamir Mountains. Its construction began in October 2016 with a ceremony that saw Tajikistan President Emomali Rahmon maneuver a bulldozer to spread earth and rock across the riverbed to block the flow of water. With the completion of the cofferdam, workers can build the main dam on the dry riverbed.
At 335 metres, Rogun will be the tallest dam in the world. Built with rockfill and a clay core, it will have six Francis turbines of 600 MW each for a combined installed capacity of 3,600 MW, making it the most powerful in the region.
The next two milestones – set for July 2018 and April 2019 – will be to build the first phase of the main dam to facilitate the putting into operation of two of the six turbines. The early start of these turbines is an important part of the project because it will allow Tajikistan to cope with internal demand for electricity as well as sell it to neighbouring countries. Proceeds from the sale of electricity will be used to finance the completion of the dam.