Silt may have reduced Bhakra capacity by 15%

Vijay Mohan

Tribune News Service

Chandigarh, December 15

The storage capacity of the Gobind Sagar reservoir at Bhakra Dam may have been reduced by over 15 per cent since its inception due to the continues inflow and settlement of silt over the past about seven decades.

Estimating this, senior functionaries of the Bhakra Beas Management Board (BBMB) said the board had decided to undertake a silt survey to assess the levels of silt deposited on the reservoir bed over the years. A decision to de-silt the reservoir would depend upon the survey’s results. Gobind Sagar has never been de-silted so far.

“We expect the survey to begin in about two months,” a senior BBMB officer said. “An external agency with the requisite expertise will execute the project, which is expected to take about three months,” he added. Over 2.27 lakh feet of the reservoir’s length would be surveyed. Silt can affect or damage the hydropower generating machinery.

Gobind Sagar’s defined storage capacity is 6.229 billion cubic metres (BCM). As on December 15, its level was 4.477 BCM, which is 72 per cent of its capacity. This year’s current level is better than the past 10-year average of 69 per cent for this time of the year.

Construction of the Bhakra Dam, which lies on the Sutlej, began in 1948 and it was commissioned in 1963. A large part of the dam’s catchment area lies in the barren areas of Lahul and Spiti district of Himachal Pradesh and Tibet. As a result, a lot of silt and loose debris get swept into its flow. 

Massive deforestation, cultivation and construction along the Sutlej’s course as well as along tributaries and rivulets that feed the main river have added to the problem of excess silt, especially during rains. 

BBMB officials said the construction of the Koldam Dam Hydropower Project upstream the Bhakra, which began functioning in 2015, had reduced silt inflow into the Gobind Sagar, but it could not be completely stopped.