I'll start and Dr. Ridal can follow.
I can reference one study for the Savannah River in Georgia. There's an island, and the ship channel is on one side of the island. They set up a study to see what the wave height was on the other side of the island as well as on the exposed side. Interestingly, due to this wave drawdown and surge phenomenon, it was actually observed on the other side of the island as well. It was not to the same magnitude. The point is that in a given situation such as downstream Montreal, there's one side exposed, but there could be effects even on the other side of the island from the shipping.
Now, again, I am not ready to say that in my study shipping is the cause of erosion—it's premature for me to say that in this particular study—but I think it has been observed in other places.