Australian firm to assess feasibility of deep-dredging operations at Bhakra to remove silt

The Bhakra Beas Management Board (BBMB) has approached an Australian firm to explore the possibility of deep-dredging operations to address the significant siltation issue in the Bhakra Dam reservoir. According to BBMB chairman Manoj Tripathi, silt has reduced the reservoir’s capacity by about 25 per cent over the years. “An Australian firm will visit the dam next week to assess the feasibility of undertaking deep dredging without lowering water levels,” he added.

No Indian firm undertakes deep dredging, and silt accumulation at the tail end of the reservoir poses a significant challenge. Another option is dry excavation of the bed when the reservoir’s water levels are depleted or purposely reduced. The reservoir level can be lowered from the maximum permissible level of 1,680 ft to 1,462 ft, exposing large areas for desilting.

Tripathi mentioned that last year, there was a plan to undertake dry excavation at the Bhakra Dam reservoir, but objections from the Himachal Pradesh Government regarding the auctioning process halted it. The dam and its reservoir span across Bilaspur and Una districts in the state. “We have held discussions at the highest level with the state government, and they have agreed to the auction of desilting, which can be done in January and February, potentially generating revenue worth hundreds of crores,” he said.

The BBMB chairman also stated that discussions on desilting reservoirs were recently held with the Secretary in the Ministry of Jal Shakti, and a policy is being formulated. Given the mountainous terrain, narrow approach roads, and irregular shape and depth of the reservoirs, dredging and excavation would be a long-drawn and highly technical project.

The designed gross storage capacity of the Bhakra reservoir is 9.8 billion cubic meters (BCM), including the dead storage capacity. The present live storage capacity at full level is 6.2 BCM, according to the Central Water Commission. The dam, which began construction in 1948 and became operational in 1963, has an installed capacity of 1,379 MW and an irrigation potential of 6,76,000 hectares.

Bhakra’s reservoir, Gobind Sagar, is over 90 km long, with a maximum depth of 534 ft. A significant portion of the dam’s catchment area lies in barren, partially sandy regions, contributing to substantial silt and debris inflow. BBMB officials estimate that 38-39 million cubic meters (MCM) of silt flows into the reservoir annually, exceeding the projected rate of 33-34 MCM.

Experts warn that if silt inflow continues without remedial measures, the reservoir’s capacity could be further reduced by 35-40 per cent by 2050.