RAWALPINDI, July 30: The power generation capacity of Tarbela Dam on Sunday touched the highest figure of 3,570 megawatts against the installed capacity of 3,478 megawatts due to improved water situation.

The spokesman for Tarbela dam project, Zarif Khan, told Dawn that power generation had recorded increase due to improved head. The dam has the maximum head of 450 feet with variation of 230 feet.

The lean flow period of the dam reservoir is from November to June when the capability reduces as low as about 1,350MW during high head from August to September. Mr Khan said the power situation has improved with the increased generation from hydel sources, which accounts for 30 per cent of the total power generation in the country. At present the power load is 9,570 megawatts, he said.

The power station located on the right bank near the toe of main dam, houses 14 power units on tunnel 1, 2 and 3. Ten units have the installed capacity of 175MW each while the remaining four units commissioned in June 1994 have the installed capacity of 432 megawatts.

Zarif Khan said the spillway gates of the dam, which were opened the other day due to the excessive inflow of water, were now discharging 129,400 cubic feet per second. At 5pm, on Sunday, he said, the reservoir level of the dam touched the figure of 1,516.58 feet.

The inflow of water was recorded at 305,000 cubic feet per second while outflow was at 253,400 cubic feet per second.

Tarbela, the world’s largest earth and rock filled dam, completed in 1974 as a component part of Indus Basin Project, is 485 feet high and 9,000 feet long and has two-gated spillways having combined discharge capacity of 1.5 million cusecs and five tunnels for irrigation releases and power generation. The dam forms a 100 square miles lake with gross storage capacity of 11.3 million acre feet and live storage capacity of 9.68 million acre feet of surplus water from Indus River for subsequent use for irrigation during low water season.

The Tarbela Hydropower Project plays a vital role in the economy of Pakistan by alleviating floods, storing water for irrigation and generating hydropower.

According to an assessment report prepared to determine increase in power generating capacity of Tarbela Dam, Pakistan is blessed with around 40,000MW of hydel power potential, of which only about 6,599MW has so far been tapped. Only 15 per cent of the hydropower potential has been harnessed so far and 8-10 per cent is under various stages of development. Thus, around 75 per cent of the potential remains unexploited.