Man-made lake of stored water (9)
I believe the answer is:
reservoir
'man-made lake of stored water' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for reservoir that I've seen before include "Area flooded" , "water over a wide area?" , "Lake used to store water for community use" , "River rose (anag.)" , "Large water store" .)