LAHORE, Dec 13: Water and Power Development Authority plans to conduct a sediment management study for Tarbela Dam to tackle decreasing water storage capacity in the reservoir due to sedimentation.
According to a Wapda press release, besides exploring ways and means to flush out sediments from the reservoir, the study also aims at determining impact of sedimentation on the downstream irrigation infrastructure.
The study is funded by the World Bank through its Water Sector Capacity Building and Advisory Services Project (WCAP).
In response to the Expression of Interest (EoI), Wapda has short-listed five joint ventures involving consulting firms of international repute, which will soon be asked to submit their technical and financial proposals for the study.
Tarbela Dam Project, an engineering marvel built in 1974, is considered to be the lifeline for national economy. Tarbela lake spreading over 259 square kilometers, has maximum elevation of 1,550 feet above the mean sea level. Average annual water inflows at Tarbela is 64 million acre feet (MAF), which brings along a huge quantum of sediments estimated at 200 million tons per year from a catchment area of more than 169,000 square kilometers.
These sediments have not only decreased the storage capacity of the reservoir but also pose a serious threat to the powerhouse structures, machines etc.The live storage capacity of Tarbela lake has dropped to 6.77maf in 2010 from the original 9.68 MAF, recording 30 per cent decrease during the last 36 years.
Earlier, Wapda had carried out five studies related to the Tarbela Dam sediment management.
The recent study was recommended by George W Annandale, a known expert on sedimentation, in the 5th Periodic Inspection, besides the task force created in Wapda, in consultation with the International Commission on Irrigation and Drainage (ICID).