My book "Thousands are Sailing: a brief song history of Irish emigration" contains 20 songs, each one supported by a contemporary prose account illustrating the same aspect, some commentary and pictures. It contains "Paddy on the canal" but as said above it has no specific location.

I know of no song which has a location on the Welland Canal - have you looked in Edith Fowke's works or at her unpublished collection which is (I believe) at York University in Toronto?