Artificial waterways (6)
I believe the answer is:
canals
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">artificial waterways</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for canals that I've seen before include "Man-made waterways" , "Artificial waterways" , "Artificial water channels" .)