LAHORE, Oct 4: Punjab is expected to start the Rabi season with a 17 per cent water shortage as the national water supplies have dropped to just over 100,000 cusecs and both dams have already started depleting.

Officials of the Irrigation Department say although the projected shortage has come down from 40 per cent to 17 per cent because of late September rains, the situation may worsen in the days to come.

The meteorological officials had forecast no rains in their advisory early August and the water planners calculated a shortfall of 40 per cent for Rabi season. However, they predicted some rain in the second advisory in mid-August and shortages were revised to 30 per cent.

In September’s advisory, there was a warning of excessive rains and fresh figures brought the expected shortage down to 17 per cent. The officials don’t rule out changes in calculations within the next two weeks.

On Thursday, the national water supplies started dipping, with the river Indus going down to 52,400 cusecs, Kabul to a paltry 13,000 cusecs, Jhelum to 18,100 cusecs and Chenab to 16,900 cusecs.

“With the monsoon now completely over and temperatures going down in northern areas, it is natural for base flow of the rivers to go down,” says an official of the Punjab Irrigation Department. In the next few days, he says, they will go down further, correspondingly increasing dependence on both dams which could not be filled to their capacity this year.

“The country took a big risk when the Water and Power Development Authority (Wapda) altered the filling criteria to store maximum water in Tarbela to fill the lake,” he says. But, it managed to fill Mangla Dam which has now become the biggest dam in the country after being raised by 30 feet. It hardly touches the pre-raising level. The country thus has the same amount of water which it used to have before raising the Mangla Dam and starts the season with the same handicap, he says.

The Tarbela Lake on Thursday came down by 6.88 feet – standing at 1543.22 feet against the optimum level of 1,550 feet – and Mangla Lake stood at 1,204.20 feet. Both the lakes have now 10.89 million acre feet of water to see the country through the Rabi season. The depletion may quicken in the next few days as outflows have started outstripping inflows; Tarbela received 52,400 cusecs on Thursday but outflow was 80,000 cusecs and Mangla received 18,100 cusecs and released 33,000 cusecs.