Smell found in empty canals and small streams (6)
I believe the answer is:
creeks
'small streams' is the definition.
(I've seen this in another clue)
'smell found in empty canals' is the wordplay.
'smell' becomes 'reek' (reeking is a kind of smelling).
'found in' is an insertion indicator.
'empty' suggests removing the centre.
'canals' with its centre taken out is 'cs'.
'reek' going into 'cs' is 'CREEKS'.
'and' is the link.
(Other definitions for creeks that I've seen before include "Small natural streams of water" , "Small streams in the US" , "Watercourses" .)