Waterway in Phoenix? (5)
I believe the answer is:
I believe this clue is a double definition.
'waterway' is the first definition.
(I've seen this before)
'phoenix?' is the second definition.
(actor River Phoenix)
'in' acts as a link.
(Other definitions for river that I've seen before include "Natural flow of water", "It flows", "Exe, Po", "x or y, so to speak", "Tees, perhaps".)