Flower feeder? (9)
I believe the answer is:
tributary
This clue is a double definition.
'flower' is the first definition.
(part of a river - something that flows)
'feeder?' is the second definition.
(I know that affluent can be written as tributary)
(Other definitions for tributary that I've seen before include "River flowing into a larger one" , "River that feeds a larger one" , "Stream flowing into a larger body of water" , "revenue from clients" , "River running into another" .)