Depicted no river or other source of moisture (3)
I believe the answer is:
dew
'moisture' is the definition.
(I have seen 'Overnight moisture ' mean 'dew' so perhaps 'moisture' could also mean 'dew')
'depicted no river' is the wordplay.
'depicted' becomes 'drew' (I've seen this in another clue).
'no' indicates named letters should be taken away.
'river' becomes 'r' (abbreviation for river).
'drew' with 'r' taken out is 'DEW'.
'or other source of' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for dew that I've seen before include "Night-time moisture" , "Moisture on grass" , "It forms on cool surfaces at night" , "Wed in morning moisture" , "Moisture deposited overnight" .)