Pakistan Water and Power Development Authority (Wapda) signed an agreement on sediment management study for Tarbela reservoir, here on Tuesday. The study aims at exploring various options to evacuate sediments from the reservoir to tackle decreasing water storage capacity in the reservoir due to sedimentation through dredging, flushing, and blowing etc.
According to the agreement, the study completion period is one year and three months, which would cost about $3 million. The World Bank will fund the study out of Water Sector Capacity Building and Advisory Services Project (WCAP). The 1974-built Tarbela Dam Project is the lifeline for national economy. The Tarbela lake spreads over an area of 259 square kilometers, with maximum elevation of 1550 feet above main 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 posing a serious threat to the powerhouse structures and machines. Tarbela lake has gone down to 6.77 MAF from its original storage capacity of 9.68 MAF, recording 30 percent decrease during the last 36 years.