LAHORE, May, 20: Tarbela Dam is losing 100,000 cusecs storage capacity every year and with that pace there will be no water available for wheat maturity and cotton sowing after five years.

These fears were expressed by experts while talking to Dawn on Monday. According to them, 100,000 cusecs water forms the irrigation supply of 10 days which means that every year Tarbela will hit the dead level 10 days earlier. The calculation has already proved correct as the dame had exhausted on March 26 in 2000, on March 15 last year, and on March 6 this year.

Increasing water shortages during the Rabi season also substantiate the point; 19 per cent during 2000, 41pc in 2001, and 51pc this year.

If the process is allowed to continue, experts claim, then the cumulated loss of next five years will be around 0.5 million acre feet, and the dam will start hitting the dead level in the last week of January. This means that the wheat crop in Sindh and Punjab will miss the most crucial second watering — booting stage during the mid-February — and last watering at the maturity stage in March. Thus, the said, the food security of the country would be in greater jeopardy than hitherto feared.

The cotton crop, which fetches around 70pc of country’s total foreign exchange, will be the next causality. After harvesting wheat, farmers in Sindh and the southern Punjab sow cotton and their dependence on water supplies from the Indus arms is total.

If a crop is sown, one can hope for some extra-irrigational interventions like timely rains or pumping out of water through tubewells. But even Mother Nature cannot help if the crop is not sown.

This will, unfortunately, be the case with cotton crop. In such a scenario, the country runs the risk of, on the one hand, losing food security and, on the other, 70pc of foreign exchange.

“Tarbela Dam was designed to store 9.5maf,” says an official of Wapda’s water wing. Out of it, around 2maf was meant to supplement the Kharif sowing during March and April. With silt inflow, the dam’s capacity has been reduced to 7.2maf — a loss of 2.3maf — during the last 26 years. The loss is 0.3maf more than of what was kept for the Kharif sowing. He lamented that the crises were not new; they had been coming for the last 26 years but no one saw through.

A hydrologist claimed that Pakistan was losing 1pc water storage capacity every year while its population was growing by 2.5pc. By this logic, he said, the country must add 3.5pc annually to the storage capacity to make for the loss. If the present storage capacity of both dams — which is around 15maf — is taken as a base line, the country will need a 5maf dam every 10 years. This is a must to feed the an ever-growing population, he said.

The failure to create new storage is playing havoc with subsoil water, says an official of the water management wing of the Punjab agriculture department.