A channel without water, we're told (6)
I believe the answer is:
strait
'a channel' is the definition.
(I know that strait is a type of channel)
'without water we're told' is the wordplay.
'without water' becomes 'straight' (as in straight whisky).
'we're told' indicates a 'sounds like' (homophone) clue.
'straight' is a homophone of 'STRAIT'.
(Other definitions for strait that I've seen before include "Narrow watery stretch" , "Difficult position" , "-- -laced (prudish)" , "Difficult state for artist" , "Narrow - artist (anag)" .)