Water flowing in street in the morning - engineers brought in (6)
I believe the answer is:
stream
'water flowing' is the definition.
'street in the morning engineers brought in' is the wordplay.
'street' becomes 'st'.
'in the morning' becomes 'am'.
'engineers' becomes 're' (Royal Engineers).
'brought in' indicates putting letters inside.
'st'+'am'='stam'
'stam' placed around 're' is 'STREAM'.
'in' acts as a link.
(Other definitions for stream that I've seen before include "Torrent" , "group of pupils split by ability" , "course" , "Constant flow of liquid" , "comprising a load of drips?" .)