LAHORE: Early water losses and reduced river flows because of lowering temperatures are threatening the prospects of dams’ filling.

The Mangla Dam is now struggling to get filled and the Tarbela Lake has started depleting even before it could get close to the optimum level.

According to Irsa, it had to release a massive 3.7 million acre feet – almost half of the Mangla Dam – to the sea early this season because Wapda was working on a rim road of the Mangla Lake and had told the Authority to keep the lake level down to 1,210 feet. Similarly, the Tarbela Dam level was also kept down to 1,481 feet to allow work on its Extension 4th Project.

These factors are now haunting Irsa which finds it hard to fill the Mangla Dam. This is despite reduction in releases from the Mangla to a bare minimum of 10,000 cusec.

According to the Irsa projections, the Mangla Dam should have achieved a level of 1,236.86 feet by July 26, whereas it was reeling at 1,229.70 feet. Similarly, the river Jehlum, which was expected to be flowing at 61,200 cusec, has dipped to mere 34,000 cusec which jeopardises the filling of dam which is 13 feet away.

Other rivers have also betrayed Irsa expectations because of slide in temperatures; the river Kabul was projected to be flowing at 67,000 cusec but was down to 39,000 cusec on Tuesday. The Irsa had hoped the river Chenab would contribute 87,000 cusec but it was flowing at only 68,000 cusec. The river Indus is also down to 205,000 cusec against Irsa expectations of 250,000 cusec.

“Yes, the Authority is struggling to fill dams, especially the Mangla Lake,” says Rana Khalid, the official spokesman for Irsa. Though the country has received seven per cent more water than what it had anticipated by July 26, early losses are hard to make up for. Irsa had expected 69maf water but it received 74maf water or seven per cent more. But out of this 5maf additional water, 3.7maf was wasted to the sea because Wapda was working on both dams – rim road repair work at Mangla and the Tarbela Extension 4th – and had asked the authority to keep lake levels low to allow it to work. The authority thus kept releasing more water from both dams to allow development work, he explains.

This loss is now becoming hard to make up for because of lowering temperatures and river flows. He hopes that the Tarbela Dam may still have chances of filling up because of longer period of expected water supplies right up to Sept 10 but Mangla has no chance of being filled.

Irsa was providing 220,000 cusec to Sindh against its demand of 133,000 cusec to maintain water level at barrages so that Sindh can operate its canal. This additional water also means that 50,000 to 80,000 cusec would continue escaping to the Arabian Sea, increasing cumulative water losses for the season, he says.

Published in Dawn, July 28th, 2016