What follows is Wapda chairman Safdar Butt’s letter to president Musharraf:
“The 920 feet high Bhasha dam is proposed to be built in Roller Compacted Concrete which is a cheaper and quicker way as compared to the Conventional Vibrated Concrete. However, because of vulnerability of roll-crete to leakage and cracking, the world engineering communities are proceeding cautiously and gradually by improving methodologies as they increase dam heights. China, Japan and Columbia have so far achieved heights of 425, 450 and 620 feet respectively.
Alternate dam materials with proven precedents, such as CVC, or Rock-fill Dam with Earth Core, are purposely not being chosen because they are not available locally and the long haulage costs of these materials would make the dam prohibitively expensive.
Failure of the dam could generate a 500 feet high water wave from the 900 feet deep reservoir, which would travel downstream leaving no other dam, barrage or bridge across the Indus River intact, washing down everything right up to its outfall in the Arabian Sea. River bank cities such as Attock, to mention only one, will get destroyed by slush leaving behind the city under a mound of sediment as high as 200 feet. At some point of time, future generations may rediscover such towns as a part of archeological excavations. My comments – Design changes were politically motivated to give the dam superiority over Kalabagh dam. Now that it is not in competition with KBD, it should be built to its original designed height of 680 feet with the CVC method of construction. Safety of the dam should be the top priority in a highly seismic region. Dam construction and politics can be mixed only with dire consequences.
ENGR KHURSHID ANWER,
Lahore, December21.