Rising flood is to make changes here? (4)
I believe the answer is:
edit
'to make changes here?' is the definition.
(make changes to text)
'rising flood' is the wordplay.
'rising' says the letters should be written in reverse (going up in a down clue).
'flood' becomes 'tide'.
'tide' reversed gives 'EDIT'.
'is' acts as a link.
(Other definitions for edit that I've seen before include "be a bookmaker" , "Rewrite" , "Prepare (text) for issue" , "Emend" , "Censor" .)