Long run wrongly associated with Canadian waterway (5,5,5)
I believe the answer is:
grand union canal
'long' is the definition.
Both the definition and answer are adjectives.
Maybe they are linked in a way I don't understand?
'run wrongly associated with canadian waterway' is the wordplay.
I cannot quite see how this works, but
'run' could be 'r' (cricket abbreviation) and 'r' is found within the answer.
'with' could be 'and' and 'and' is present in the answer.
'canadian' could be 'can' (I've seen this in other clues) and 'can' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for grand union canal that I've seen before include "Way with water" , "watercourse" .)