Originally Posted by a64pilot
What is a wing dam?
Never mind, I looked it up, I had never heard the term used before
They are properly understood as a pile of rocks placed right at the edge of the navigable channel in, probably, 1904, extending up to the (then) surface of the water, which has since been pushed around by ice and barges, and covered by water now that the river is kept higher by the locks and dams, so that it poses an uncharted hazard to anyone trying to get from the navigation
channel to the bank of the river.