Dams contained surge, spared doom downstream, says BBMB

Bhakra Beas Management Board (BBMB) Chairman Manoj Tripathi today said dams had played a crucial role in protecting Punjab from far greater destruction by providing a critical buffer against excessive monsoon inflows. He said without the presence of dams, large-scale devastation would had struck as early as June.

Tripathi said the Pong Dam that lies on the Beas in Himachal Pradesh witnessed unprecedented inflows this year — 20 per cent higher than the previous record of 2023.

He pointed out that this necessitated increased discharge, but the water channels downstream in the adjoining areas of Punjab and Himachal Pradesh didn’t had adequate carrying capacity.

He added that said since the inflows were about double the holding capacity of the reservoir, the excess water had to be released through the spillways.

Outflow was capped at one lakh cusecs even though inflows were 2-2.5 lakh cusecs.

“Water flowing in during the later part of the monsoon cannot he held back. We have taken up the issue with the partner states to ensure that the rivers and canals downstream of the dams have adequate carrying capacity to accommodate additional water,” he said. “During our Technical Committee meetings we also stressed upon the states to strengthen embankments of the rivers,” he added.

He said had more water been released to Haryana earlier, the current reservoir levels would had been lower by 3–4 feet, which could have created “some” cushion to absorb the heavy inflows due to excess rains. “There is also a constraint at Harike, in Punjab, where the Sutlej and Beas merge, and is also a low-lying area,” he added.

The BBMB manages dams and power projects on the Sutlej and Beas. Those on the Ravi are managed by the Punjab government. The capacity of the Pong reservoir is around 5 billion cubic metres (BCM), the inflows during the monsoon this year were 11.70 BCM compared to the previous high of 9.5 BCM.

At Bhakra, which is on the Sutlej, the inflows this year have been recorded at 9.11 BCM. Though being higher than normal, it’s roughly equivalent to previous highs.

The water level at Bhakra on Friday was about one-and-a-half feet below the permissible limit of 1,680 feet, while at Pong it was four feet above the permissible limit of 1,394 feet. Technically, water level at Bhakra can go up to 1,690 feet while at Pong it can go up to 1,410 feet. The limits of 1,680 and 1,390 feet have been fixed keeping in mind safety factors, deflection, discharge capacity and the possibility of freak weather events.

Tripathi said based on data provided by the BBMB and the India Meteorological Department, a “reservoir rule curve” was developed by the Central Water Commission in 2023 after floods were experienced. This stipulates the water level that is to be maintained at a particular time and guides storage and release decisions.

The BBMB Chairman said the policy to de-silt the reservoirs was being framed.

Deposit of silt at the tail end of reservoirs over the years had reduced the storage capacity at Bhakra by around 25 per cent, he said.

As there were some observations by the Himachal Pradesh Government on the auctioning process for de-silting reservoirs, discussions in this regard had been held at the highest level.

While de-silting operations would involve depleting the reservoirs, another option is deep-dredging without lowering the water level. Tripathi said, “Next week, a firm from Australia is visiting the Bhakra Dam to assess the feasibility of this process.”