Works harnessing power in river succeeded (6)
I believe the answer is:
opuses
'works' is the definition.
(an opus is a creative work)
'power in river succeeded' is the wordplay.
'power' becomes 'p' (symbol in physics).
'in' is an insertion indicator.
'river' becomes 'ouse' (Yorkshire river).
'succeeded' becomes 's' (genealogical abbreviation).
'p' placed within 'ouse' is 'opuse'.
'opuse'+'s'='OPUSES'
'harnessing' is the link.
This may not be correct. It may belong to another bit of the clue.
(Other definitions for opuses that I've seen before include "Musical works" , "pieces of music" .)