List of charges resulting from petty quarrel about a river (6)
I believe the answer is:
tariff
'list of charges' is the definition.
(I've seen this before)
'petty quarrel about a river' is the wordplay.
'petty quarrel' becomes 'tiff' (I've seen this before).
'about' indicates putting letters inside.
'river' becomes 'r'.
'a'+'r'='ar'
'tiff' placed around 'ar' is 'TARIFF'.
'resulting from' is the link.
(Other definitions for tariff that I've seen before include "List of duties on imports or exports" , "Import or export duty" , "Import/export tax" , "Sentencing scale" , "Import duty, tax" .)