Flood stoppers (6)
I believe the answer is:
levees
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">flood stoppers</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for levees that I've seen before include "Banks" , "Landing piers on rivers" , "River embankments" .)