Aswan Dam river (4)
I believe the answer is:
nile
'aswan dam river' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nile that I've seen before include "River at Luxor" , "Cleopatra's river" , "River associated with Cleopatra" , "Egypt's river" , "World's longest river" .)