The U.S. Army Corps of Engineers advises recreational boaters and commercial mariners that recent high water levels may be concealing some pile dikes on the Columbia River.  Pile dikes are frequently just below the surface during high water events and can cause serious damage to vessels attempting to transit over them.  Pile dikes, also called wing dams, are wooden structures that extend from the shore into the river.  The structures have a variety of uses ranging from protecting the shore to managing the flow of the navigation channel.  Commercial and recreational mariners should review the Corps’ channel conditions maps regularly for the locations of pile dikes and other obstacles.  The maps are located at the Corps’ website.