With the Central Water Commission (CWC) forecasting rapid rise in the inflows into Almatti and Tungabhadra dams in Karnataka and the resultant flood to Srisailam, the spillway gates of Nagarjunasagar, another common reservoir of Telangana and Andhra Pradesh, are likely to lifted in the next couple of days.
The TSGenco has taken up hydel generation at the dam site power house in coordination with the dam authorities on Wednesday evening commencing release of flood water of over 13,100 cusecs to the river course. But, it was stopped a couple of hours later. The authorities of Nagarjunasagar dam assessed on Wednesday morning that spillway discharge of flood could happen either on August 22 or 23. Last year, they were lifted on August 12.
However, the constant increase in flood to Srisailam from Krishna and Tungabhadra rivers and the release of flood from there through the spillway coupled with the CWC forecast of more heavy rains in Central Maharashtra, the catchment area of Krishna and many of its tributaries, for the next four-five days have made them revise the assessment by the evening. The inflows into Srisailam are expected to cross 4 lakh cusecs.
“We have another 50 tmcft of flood cushion in Nagarjunasagar reservoir as of Wednesday night. The flood discharge from the spillway most probably may commence in a couple of days,” a senior engineer told The Hindu.
The CWC has forecast that flood from Upper Krishna, Dudhganga, Panchganga and Ghataprabha catchment areas due to widespread heavy rains for the last one week would rapidly increase the inflows into Almatti over the next two-three days with likelihood of the trend continuing further.
Flood monitoring officials quoting the CWC bulletin stated that heavy rain was recorded in the catchment areas of Krishna and many of its tributaries in Maharashtra and Karnataka during the 24-hour period up to 8.30 a.m. on Wednesday. It is stated that 12.1 cm rain was recorded in Augumbe (Karnataka), 9.7 cm in Mahabaleshwar, 8 cm in Koyna and 5 cm in Warana areas increasing the chance of more flood into Almatti and Tungabhadra dams.
In the upstream of Krishna, Almatti was getting a flood of over 2.37 lakh cusecs flood and discharging over 2.5 lakh cusecs, Narayanpur was getting 2.8 lakh cusecs with supplementation from Malaprabha and releasing over 2.83 lakh cusecs flood and Jurala was getting 3.14 lakh cusecs including supplementation from Bhima.
In the Godavari Basin, heavy flood of about 80,000 continues to reach Sriramsagar taking its storage beyond 63 tmcft against its capacity of 90.3 tmcft on Wednesday evening. Yellampally was also getting inflows of over 54,000 cusecs with supplementation from Kaddam and discharging over 53,00 cusecs. Singur, Nizamsagar, Mid-Manair and Lower Manair projects were also getting some inflows improving their storage.
Heavy flood in Godavarai from Kaleshwaram and downstream has already made 893 tmcft flow waste into the sea from Dowlaiswaram as of Wednesday morning including 342 tmcft during the last two days. Over 44 tmcft of water has also gone into the sea from Prakasam Barrage with nearly 60,000 cusecs flood still being discharge into seas with the help of rains in the local catchment areas below Pulichintala reservoir.