One of the most common misgivings about dams is that they reduce flow in the river; this is not correct as dams do not consume water, they store surplus flood water over a 3 month period for use during the remaining 9 months. The example of Mangla and Tarbela dams is before us. The record in the Sindh irrigation department will show that the flow in the canals of Sindh increased by 7 million acre feet (maf) after the construction of the two dams and there was a corresponding increase in the number of acres under cultivation in Sindh. This could not have happened if the dams had reduced water flow. Again, as recorded by the Sindh irrigation department, 18 maf of flood water was lost in 2013, and Kalabagh dam would have stored and saved 6.1 maf of water out of which Sindh and Punjab would both have got 2.25 maf, with each province given an increased ability to cultivate an additional 6 lakh acres, a total loss of 1.2 million acres.

ENGR KHURSHID ANWER,

Lahore, May 29.