A flurry of rain gets beneath split on a riverbank (8)
I believe the answer is:
riparian
'on a riverbank' is the definition.
(riparian means relating to a riverbank)
'a flurry of rain gets beneath split' is the wordplay.
'a flurry of' is an anagram indicator (I've seen 'flurried' mean this).
'gets beneath' becomes 'pari' (I can't explain this - if you can you should give a lot more credence to this answer).
'split' indicates putting letters inside (some letters split a word into two).
'rain' with letters rearranged gives 'rian'.
'rian' enclosing 'pari' is 'RIPARIAN'.
Can you help me to learn more?
(Other definitions for riparian that I've seen before include "living by the river" , "Relating to river banks" , "Relating to a riverbank - Iran pair (anag)" , "near a river" , "associated with banks" .)