The small amount of water stored in small dams in hilly areas where canals cannot be dug are generally at considerable distances from each other. They cannot be integrated to augment the flow of any major river. This water is only for local consumption like small-scale farming, fruit orchards and community services. Power generation is also low, due to low head of water and power so generated cannot be integrated in the national grid through miles of transmission lines. Wind and Solar technology can generate large amounts of energy, but just like thermal power generation with oil and coal, these will not produce any water. For water, there is no substitute for a mega dam. How many small dams can give us 6.1 million acre feet of water? -KHURSHID ANWER, Lahore, via e-mail, August 27.