Provides free rein for river approach
I believe the answer is:
leeway
'provides free rein' is the definition.
I can't tell whether this defines the answer.
'river approach' is the wordplay.
'river' becomes 'lee' (I've seen this in other clues).
'approach' becomes 'way'.
'lee'+'way'='LEEWAY'
'for' is the link.
Can you help me to learn more?
(Other definitions for leeway that I've seen before include "Allowance" , "Room for movement within limits" , "Margin of tolerance" , "Space for free movement" , "Margin of safety" .)