I went out exploring yesterday and discovered the Tail Race Canal shown on the lower right of the above map next to the Grand Trunk Boating Club. This canal was subject to confusion as many thought it was what was left of the Petite Rivière St-Pierre but was/is in fact the water outlet canal of the Atwater Filtration Plant. The Petite Rivière St-Pierre emtied in the river between Regina and Strathmore. A 1912 map shown on our society's site wll give you more details: ww.ville.verdun.qc.ca/shgv
Check the photo section.
The canal is near the Champlain bridge access road to the left of the Mgr Richard Secondary School and is about 1000 feet long.. On the right of the school is the Arthur Thérien Park. I was told by a fisherman fishing in the canal that the city empties the snow at the end of the canal and that boats also entered the canal. This canal is the dividing line between Verdun and Pt St Charles.
I got this photo from Google Earth. Incredible is the word.