LAHORE, Oct 10: Earthquake has not affected either the Mangla or Tarbela dam, according to Muhammad Mushtaq Chaudhry, member (water) Wapda. He told Dawn that the authority deputed a team of experts to assess the impact of the quake immediately after it had struck. The exercise was carried out according to the set international criteria for low-middle-and high-intensity quakes. Since it was a high-intensity quake, the authority operated according to the internationally accepted procedures.
Mr Chaudhry said that there were over 3,000 gadgets installed in the main body of the dams in the base, hills and poles. These gadgets are supposed to assess any damages, including those caused by jolts and tectonic movements.
“The Wapda team took the entire day extracting readings, from the gadgets and luckily no damage was detected,” he said.
He claimed that Wapda’s teams of experts were still on the job, monitoring the aftershocks and their effects, if any. It has been three days since the earthquake struck, but no damage has been reported from any part of the two big dams.
Brig Mushtaq Ahmad (retired), general manager hydel (north), also said that both the dams were safe.
He claimed that all dams in the world had fool-proof systems for assessing any damage, and Pakistan’s dams were no exception.
These were fully equipped to gauge seismic activities and water pressure at all times, he said.
According to Brig Ahmad, the design of the dams always takes into account the seismic factor and the designers implement the plan in a very safe manner.
“The dams can absorb major jolts because designers take the highest recorded quakes in the history of the area and then design the dam for a higher safety. It is not to claim that nothing happens to dams, but only to prove that dams have a self-sustaining, in-built mechanism and both Tarbela and Mangla have successfully withstood the impact of the latest quake,” he said.
Talking about the possible impact of the quake, Chief Engineer Dams (Wapda) Husnain Afzal says that dams are built to withstand a certain level of pressure generated by the lake water. If a jolt increases water pressure beyond the safety factor, it can simply uproot and overturn the dam.
Earthquakes could also effect internal cohesion of the particles which stop seepage beyond the permissible limit and define the life span of a dam. If an earthquake has an impact on the homogeneity of these particles, it could immediately increase seepage from the dam and affect the dam’s safety and life.
The dams also have strain points. Earthquakes could also alter pressure of these strain points and affect the dam operations.
The chief engineer said that these were the specific areas that experts looked for in any impact assessment, especially after an earthquake.
