Become depleted (3,3)
I believe the answer is:
run dry
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">become depleted</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for run dry that I've seen before include "Exhaust" , "go impassive" , "Come to an end" , "Cease to flow or have any water" , "get exhausted" .)