Sprinkler that makes channels deeper (7)
I believe the answer is:
dredger
'sprinkler' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for dredger that I've seen before include "Waterway deepener" , "ship" , "Flour or sugar sprinkler" , "Vessel for clearing river bed" , "Barge-like vessel" .)