Akhtar Ali writing from US on the small dams has said, "Making small dams is a low-cost way of locally conserving rainwater and using it for irrigation, clean water supply and electric power for households". Correct, small dams serve only the locality they are built in. Already there are hundreds of small dams in Pakistan. There is a whole 'Small Dams Organization' in WAPDA. The small quantities of water stored in these dams (which are naturally at great distances from each other) cannot be integrated to augment the flow of any major river. Similarly, their meager power generations cannot possibly be integrated through many miles of transmission lines to feed the national grid. The demands of Pakistan's irrigation and power are of a much larger scale. Coal, solar and wind would one day, no doubt, augment the very expensive thermal power but none of these will give us water. Lining of canals and other means of conservation will save water but would still not store it for later use. Only mega dams can transfer water from the surplus Kharif period to the lean Rabi period, the two sowing seasons of Pakistan. Surely, we do not want to end up as a 'single season' country? How long would Mangla and Tarbela dams continue to meet the multifarious demands of our ever-growing population? -KHURSHID ANWER, Lahore, via e-mail, August 9.