It is not only the heavy rains in Sindh which are flooding the countryside but also the torrential rains in the north which are swelling the Kabul, Chitral, Swat, Haro and Soan rivers which are all flowing down to Sindh adding to the flood havoc. Until these tributary rivers of the Indus are trapped at source they will keep flooding Sindh even after Bhasha dam is built. A look at the geography of the country will show us that it is only a dam at the Kalabagh site which can trap the flood waters of these rivers. Also utilise their surplus flows for irrigation and power generation. It is only ignorance of these simple facts that is keeping the country from reaping the benefits of flood control, irrigation and power generation.    ENGR KHURSHID ANWER, Lahore, September 11.