FAWAD YOUSAFZAI
ISLAMABAD - Work on the important 1410MW Tarbella 4th extension project has been stopped due to increase in the water level in the reservoir, it was learnt reliably here Friday.
Besides Tarbella 4th extension, work on Khaliq Abad section of Mangla Dam has also come to a standstill. The contractor stopped working on the intake component of the Tarbella 4th extension project, evacuated the staff and erected gates for the protection of the already-completed work, official sources told The Nation here.
Last week in a meeting, presided over by Wapda chairman, the reservoir situation was discussed and it was decided to expedite the work and inform the World Bank, who is the financier of the project, of the possible delay. Under the fourth extension project, a power house would be set up at tunnel four. The current tunnel function is to release irrigation water before reservoir is raised to spillways level.
The Tarbela dam was built in 1970s with a generating capacity of 3,478MW. The decision to complete the Tarbela-4 project would take the capacity to 4,888MW.
Wapda was planning to complete work on fourth extension project a year before its original deadline. An additional sum of Rs 5 billion was paid to the contractor just to accelerate the work on the project but unfortunately it didn’t happen mainly because of lack of monitoring and inefficiency. The original completion date of three units of the Tarbela-4th extension hydropower project was scheduled in February 2018, but Wapda was planning its completion in June 2017.
The stoppage of work will cause delay in the scheduled completion of the 4th Extension project on time. Tarbela dam was built to store water for irrigation purpose and electricity was a by-product. Hence, Wapda is bound to take permission from the regulator, the Indus River System Authority (Irsa), for the release of water. Irsa mandate is to meet irrigation demands of provinces. The contractor has erected coffer dam 1,512 feet above mean sea level in consultation with the Indus River System Authority (IRSA). This was determined keeping in view the water inflow pattern to the reservoir, where construction work could be continued until the reservoir reached the level of 1,490 feet.
Wapda had requested IRSA to keep the water level in reservoir at 1490 feet till July 15. But the coffer protection was not strong enough and later it was requested to keep the water level at 1483 feet, the source said.
As per the estimates, the water level in the reservoir would have increased to 1,483 by mid-July 2016, and subsequently over flow the coffer dam. Once the water attains the 1,505 feet level in the reservoir, it could have been released through spillways. Prior to this level, the water flows out of the reservoir from tunnels one, two, three, and five. Due to the pre-monsoon rains and abnormal increase in temperature in the catchment areas, Indus River average inflows reached 350000 cusecs, higher than the last five years average during June, respectively. Maximum capacity to release water from tunnels one, two, three, and five was 190,000 cusecs, therefore, the remaining water would automatically stay in the reservoir. Resultantly, the storage level started increasing and the contractor stopped working on the intake component of the project. The water level reached 1497 feet soon after the contractor stopped working and now they will be able to start work only after the monsoon and high water season is over, the source maintained.
It is pertinent to mention that last year also work on the project was delayed by 40-45 days due to high level of the reservoir.
Wapda has an army of workforce but when it comes to the implementation of important projects its efficiency is zero, the source maintained. Wapda has failed to play the role of good monitor, the source said.
Similarly, work for the repair of Khaliq Abad portion of Mangla Dam was under progress. The contractor had erected 1200 feet of coffer dam. But now it has informed the IRSA that the actual length of the coffer dam is 1180 feet, and keep the level of the reservoir at 1210 feet till June 30.The contractor was also facing problem for the project after the imposition of ban by Supreme Court on the crushing machines in Margalla hill. Resultantly, they have to stop work on the project as they were unable to meet the IRSA’s demand.
Meanwhile, WAPDA has decides to reconstruct damaged portion of Mirpur-Kotli dual carriage way from its own resources. As a mark of goodwill gesture for the people of Azad Jammu & Kashmir (AJ&K), WAPDA has decided to reconstruct the stretch of Mirpur-Kotli dual carriage way at Khaliqabad, which collapsed in November 2014. WAPDA will also take remedial measures for protection of the adjoining affected portion of the reservoir.
The Indus River System Authority has increased outflows from the Mangla dam to bring the water level to 2000 ft from 1206 ft above sea to carryout urgent repairs including construction of retaining wall with specified design and compaction of the material for road foundation.