Little brook (4)
I believe the answer is:
rill
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">little brook</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 rill that I've seen before include "Small stream" , "Flowing water" , "Brooklet" , "Burn" , "Flow of water" .)