ISLAMABAD: The country continues to lose its water storage capacity as accumulation of silt has decreased Tarbela Dam’s storage space by another two feet.

An official of the ministry of water and power told Dawn that the dead storage level of the dam had been increased to 1,380 feet from 1,378 feet a few days ago because of the rising level of silt. As a result, the storage capacity of the dam has decreased by two feet.

The dead level had been increased to 1,378 feet from 1,376 feet about two years ago, the official recalled and said the dam was gradually losing its capacity as construction of a dam in upstream of Tarbela got delayed for one reason or the other.

“There is no economically viable option to stop loss of storage capacity at Tarbela except to build dams in the upstream to reduce the amount of silt reaching one of the two major reservoirs of the country.”

He said the change in the storage parameters had been made on the recommendations of the Water and Power Development Authority (Wapda) on the basis of annual analysis of various factors relating to the dam. Wapda’s technical team on dams had recommended an increase of four feet in the dead level but the change was kept at two feet to avoid a drastic cut in discharges.

He said the country’s live storage capacity had dropped by about 30 per cent despite an addition of about 2.9 million acre feet (MAF) capacity through Mangla dam upraising project.

The official said Tarbela alone had lost about 35 per cent of its designed capacity of about 9.7 MAF which had come to 6.2 MAF.

Technical studies had been conducted a few years ago for flushing out huge sediment stock in the reservoir to revive some storage capacity, he said. But the proposed methods were not adopted because they were either technically dangerous or economically unviable.

In overall terms, the country’s total water storage capacity is less than 30 days of minimum requirements, which is considered too low and close to water scarcity against global standards of 120 days of coverage.

This contributes to lower gross domestic product. The country could not achieve its GDP growth rate during current fiscal year mainly because of poor performance by agriculture sector.

In comparison, India can have storage for up to 220 days, Egypt for 1,000 days, Australia for 600 days and the US for about 900 days.

Pakistan is estimated to be declared a water-scarce nation by 2025 unless new capacity addition is achieved. The country’s per capita water availability has dropped from over 5,300 cubic metres in the 1950’s to about 1,000 cubic metres now which is the scarcity benchmark.

Water flows improve

River flows have significantly improved over the past few days because of rising temperature in the northern areas, particularly Skardu, and resultant snow melting.

According to official data, flows in River Indus at Tarbela increased from 79,900 cusec on Friday to 105,000 cusec on Sunday.

On Saturday, total river flows were recorded at 282,000 cusec at rim stations which have risen to 307,000 cusec on Sunday. The total river flows were recorded at 253,000 cusec on Friday.

As a result, the Indus River System Authority (Irsa) has started some conservation at Tarbela and Mangla dams despite increased discharges, which is helping higher electricity generation.

The water level at Tarbela dam has, therefore, increased to 1,392 feet on Sunday from 1,390 feet on Friday.

The discharges from Tarbela which stood at 80,000 cusec on Friday were increased by Irsa to 88,200 cusec on Saturday and further to 93,600 cusec on Sunday.

The water level at Mangla Dam is also being gradually increased and stood at 1,174 feet on Sunday against 1,173 feet on Friday.

Published in Dawn, June 9th, 2014