LAHORE, Sept 8: Tarbela and Mangla Dams may start depleting shortly in the wake of the Punjab’s demand for an immediate supply of 60,000 cusecs from the Indus arm.

The additional demand was made because the province needed water to save the standing crops of cotton, rice and sugarcane, an irrigation department official said.

Punjab, he said, had been forced to seek additional water from the Indus arm in view of declining supply from Chenab and Jhelum rivers. “We need 120,000 cusecs — 60,000 cusecs each from Tarbela and Mangla,” he said.

Inflow to both reservoirs has shown a steep decline during the last one week. The Indus dipped from 300,000 cusecs to around 100,000 cusecs on Saturday, and the Mangla arm went down from 150,000 cusecs last week to 57,200. This shortfall would be met by the additional supply from the two dams, he said.

The combined river flow on Saturday dipped to another seasonal low of 183,000 cusecs — almost half of the country’s total requirement.

The Indus river at Tarbela went down to 106,500 cusecs. Over 92,000 cusecs were released and 8,100 cusecs stored in the lake. The dam level now stands at 1,552 feet — two feet over its maximum. The lake stores around 7.3 million acre feet (MAF) of water against its full conservation level of 7.2maf. The Jhelum river at Mangla dipped further to 21,500 cusecs which was subsequently released to maintain the lake level at 1,206 feet — four feet above the optimum level.

“The dams have hardly been filled when news of their depleting has hit the ears,” an ex-member (water) of Wapda deplored. Pakistan, he said, would lose both food security and cash crop — cotton — if another dam was not built during the next five years.