Diverts rising waters, skirting problem (6)
I believe the answer is:
amuses
'diverts' is the definition.
('amuse' can be a synonym of 'divert')
'rising waters skirting problem' is the wordplay.
'rising' says the letters should be written in reverse (in a down clue, letters go up).
'waters' becomes 'sea' (the sea is water).
'skirting' is an insertion indicator.
'problem' becomes 'sum' (arithmetic problem).
'sea' going around 'sum' is 'sesuma'.
'sesuma' written backwards gives 'AMUSES'.
(Other definitions for amuses that I've seen before include "Diverts" , "Makes (someone) laugh" , "provides entertainment" , "Entertains" .)