Sketched river during daybreak (5)
I believe the answer is:
drawn
'sketched' is the definition.
(I've seen this before)
'river during daybreak' is the wordplay.
'river' becomes 'r'.
'during' means one lot of letters goes inside another.
'daybreak' becomes 'dawn' ('dawn' can be a synonym of 'daybreak').
'r' inserted inside 'dawn' is 'DRAWN'.
(Other definitions for drawn that I've seen before include "showing some tension" , "Closed" , "Looking strained, sketched" , "Portrayed" , "It was a tie" .)