Tribune News Service
Chandigarh, August 21
While reducing the outflow from Bhakra Dam’s floodgates tonight, the authorities have decided to bring down the water level in the reservoir, which is hovering near the top mark, by at least 5 feet over the next few days to handle the possibility of any future weather event as well as to counter the unusually high deflection of the dam’s structure.
“The water level this morning was 1,679.5 feet, which will be brought down to 1,675 feet. A special technical committee meeting to review the situation was held yesterday in which all members of the partner states were of the view that the water level should be reduced by five feet,” said DK Sharma, chairman, Bhakra Beas Management Board (BBMB) today.
In the evening, the BBMB decided that in view of inflows reducing to 45,000 cusecs and forecast of low rainfall in the coming weeks, the discharge from the spillway would be reduced from 41,000 cusecs to 18,500 cusecs. The spillway gate opening would be lowered down to four feet from the present eight feet.
The reservoir’s permissible limit is 1,680 feet and the water level had gone past it following heavy rain in the catchment area. At present, the BBMB is releasing 40,000 cusecs through the spillway, in addition to 36,000 cusecs through the power generation tunnels to reduce water levels.
“After assessing inflows, the BBMB had released more water during May and June. The level had been brought down by 20 feet from 1,624.18 to 1,604 feet by June 25, before the onset of monsoon,” Sharma said while trying to dispel public misperception that floods were the result of water being released from Bhakra.
Stating that the BBMB had no option but to discharge excess water, Sharma said a host of factors, including quantum of inflow, meteorological forecasts, seepage levels and deflection of the dam had to be taken into account.
“The deflection experienced this time was among the highest such recorded instances due to the intense pressure of water,” he said.
Pointing out that this year, Punjab had experienced the worst floods since 1988, Sharma said controlled release of water could successfully handle the situation. The gates of the spillway were initially opened only by three feet and thereafter by eight feet. In 1988, the gates had been opened up to 22 feet. The maximum discharge capacity of the spillway is four lakh cusecs.
Peak water generated in the Sutlej at Ropar headworks during the floods was 2.4 lakh cusecs, most of which came from rivulets downstream of the dam. Rajasthan’s requirement is 12,500 cusecs and since there is no storage means downstream of Ropar, water eventually went waste by flowing across the border.
Sharma added keeping in mind the long-term health of the dam and condition of the reservoir, several projects had been initiated. This includes allocation of Rs 220 crore for undertaking a study and related works under phase-2 of the Dam Rehabilitation and Improvement Project that would cover structural, hydrological, seismic and geo-physical aspects.
Further IITs at Roorkee and Ropar had been roped in to identify areas along the reservoir’s periphery that were prone to silt inflow and to assess the commercial exploitation of silt dredged from the reservoir bed.
Reservoir level status
Permissible 1,680 ft
Current 1,679.5 ft
Target 1,675 ft
Current inflow 45,000 cusecs
Current discharge 41,000 cusecs
Target outflow 18,500 cusecs