Twice this year I witnessed an interesting phenomena along the old Champlain Canal trail North of Waterford, New York. It occurs when the old canal, which serves as overflow for the current canal, is draining out due to lock E2 being filled and then the water abruptly rushes back in with the emptying of lock E3.
The first time I witnessed it early this past Summer I thought it was a dog, deer or person in the water but then the wall of water about a foot high came rushing past with the level remaining at that height after the crest passes. That first time I wasn't prepared to document the wave but since then, I've been looking out for it, prepared to take some quick shots.
On October 27th, I was walking along the path with my 5D Mark III and 28-105mm lens, heading South back toward Waterford when I heard the wave coming. The canal had been draining out, as before, just prior to the influx. I grabbed these shots as the wave swept past.
This particular spot is about a quarter mile North of the village.