"The silt content in the turbulent river was higher than the permissible limit, in both the Sutlej and Spiti rivers, due to rapid melting of snow in the mountains of Tibet and India," official of the country's largest hydel project said on Tuesday.
Rapid melting of snow brings with it the top soil which raises the parts per million (PPM). Ideally it should remain below 4,000 PPM to avoid damage to the heavy machinery.
"The water discharge levels are higher in the Spiti river than the main Sutlej river. The PPM in the combined waters of the two rivers at the dam site still remains high at 5,000 PPM on Tuesday," official of the Sutlej Jal Vidyut Nigam Ltd (SJVNL), which runs the Nathpa project, said.
The official added that the fine dust particles could not even be separated by the desilting process at the dam which can corrode the heavy machinery of the power house.
The daily power generation loss is estimated at Rs 9 crore as all the six giant turbines of the project are silent for the past one week.This has worsened the power crisis to the hungry northern grid, which feeds all the northern states. The demand is very high in the summer season.
The Nathpa hydel project started commercial generation in 2004. The world bank-funded project was built by the SJVNL at a cost of Rs 8,630 crore.
