5The four each of half mile long, tunnels through the right (rock) abutment initially served for the diversion of water during the final phases of construction of the Project. Now, they are being used for Power generation (tunnels 1, 2, 3 and eventually 4). The discharge capacity of each irrigation tunnel at higher reservoir elevations is approximately 90,000 cusecs (2,549 cumecs). The discharge pass through energy dissipater structures and the water returns to the river. A fifth tunnel on the left bank designed to augment irrigation releases upto 80,000 cusecs (2,265 cumecs) at high reservoir level, has also been added to the project.

 

Tunnels at Right Bank

Number 4
Length 2400 feet each (732 M)
Diameter (u/s gate shafts) 45 feet (13.72 M)
Diameter (d/s gate shafts) 36 feet (10.97 M)
Discharge Capacity 90,000 cusecs (2,549 cumecs)

Tunnels at Left Bank
Length 2760 feet (841 M)
Diameter (u/s gate shafts) 43.5 feet (13.26 M)
Diameter (d/s gate shafts) 36 feet (10.97 M)
Discharge Capacity 80,000 cusecs (2,265 (approximately) cumecs)


In Pictures

Tarbela (Spillw...
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Tarbela Dam
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Tarbela Dam
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Tarbela Dam
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Tarbela Dam
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Tarbela Switch ...
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Tarbela Dam
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Tarbela Dam
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Tarbela Dam
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Tarbela Dam
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