Artificial body of water and river rose differently (9)
I believe the answer is:
reservoir
'artificial body of water' is the definition.
(body of water made by people)
'river rose differently' is the wordplay.
'differently' is an anagram indicator.
'river'+'rose'='riverrose'
'riverrose' is an anagram of 'RESERVOIR'.
'and' is the link.
(Other definitions for reservoir that I've seen before include "Store for water etc" , "Area flooded" , "Man-made lake of stored water" , "Source of water supply" , "Man-made lake or tank" .)