Soup, cold, to take on the river (8)
I believe the answer is:
consomme
'soup' is the definition.
(consomme is a kind of soup)
'cold to take on the river' is the wordplay.
'cold' becomes 'C' (eg on taps).
'to take' says to put letters next to each other.
'the river' becomes 'somme' (I've seen this before).
'c'+'on'+'somme'='CONSOMME'
(Other definitions for consomme that I've seen before include "Clear soup usually of beef, veal or chicken" , "starter course" , "Liquid food" , "Clear soup made with concentrated stock" , "Clear French meat soup" .)