Your staff reporter in his Call to protect ecology (Nation Oct 27, page 3) has stated that continuous fall in quantum in floods due to construction of reservoirs in upper part of the country. For one, reservoirs can be built only in the upper parts of the country and this is not because of some sinister design as he appears to be implying. Second, the reservoirs have not stopped floods of lesser intensity, which recur every year. Thirdly, Tarbela dam increased canal supplies by 25 percent. This could only have been done by increasing the flow in the Indus and not by decreasing it. The flow to the Indus delta actually decreased when Kotri barrage was built and three big canals taken out from it. Ten big canals at Guddu and Sukkur barrage were already depleting the Indus river. It is at the barrages that rivers get depleted and not at the dams, which actually add to the supply side. KHURSHID ANWER, Lahore, October 27.