As a civil engineer I am amazed by the ignorance of the commentators and the title of this video. What has been a typical construction sequence is now being ridiculed and smeared. In a typical dam construction the water would be re-routed to man-make by-pass tunnels first by blocking the sides of a river to construct the tunnel in the dry. When the bypass tunnels are ready, the river flow can then be stopped and then safely diverted. The dumping of rock is to stop the river, downstream of the tunnels, and to form a temporary dam to allow the permanent dam to be constructed in dry condition, often by excavating unsuitable soil to bedrock, protecting the river bed with concrete and various intake structure. When the permanent dam is finished the temporary dam could be dredged and removed. It is an universal construction method by using soil and rock to form temporary works!