Two irrigation tunnels of the world's largest earth-filled dam, the Tarbela Dam in Pakistan, have been closed after their stilling basins were seriously damaged during operational tests.
GV Engineers checking tunnels.
SV PAN Water pouring from tunnel.
SV TILT UP FROM Rushing water to engineers on parapet. (2 shots)
GV Gushing water and engineers at site. (2 shots)
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Background: Two irrigation tunnels of the world's largest earth-filled dam, the Tarbela Dam in Pakistan, have been closed after their stilling basins were seriously damaged during operational tests.
The dam harnesses the waters of the mighty Indus river and gives hope of a better life for Pakistan's 72 million people, but it has experienced difficulties since it was due to go into operation in 1974.
In the latest difficulties, divers have discovered a cavity in the wall dividing the outlets in one of the tunnels. But the damage to the other tunnel is more serious. There, the outflow has eroded the concrete slabs paving the floor of the stilling basins' shoot.
Difficulties with the stilling basins have occurred several times and the only tunnel and basin which is operating satisfactorily is one designed by Pakistani engineers.
The latest damage is to be assessed during a four-day meeting later this month by the world's top irrigation experts. It's thought the experts may recommend the re-designing of at least two of the damaged basins. If this is the case, the commissioning of the two tunnels could be put off for about three years.
The damage to the two tunnels has deprived Pakistan of water for irrigating about two million acres (800,000 hectares) of wheat and if the commissioning of the tunnels was delayed, the country would suffer a major loss of crops.