Last of sediment hauled up to take away (7)
I believe the answer is:
detract
'take away' is the definition.
(I know that take away can be written as detract)
'last of sediment hauled up' is the wordplay.
'last of' suggests the final letters.
'hauled' becomes 'carted' ('cart' can be a synonym of 'haul').
'up' says the letters should be written backwards (in down clue: letters go upwards).
The last letter of 'sediment' is 't'.
't'+'carted'='tcarted'
'tcarted' backwards is 'DETRACT'.
'to' acts as a link.
(Other definitions for detract that I've seen before include "Belittle" , "Slight" , "Devaluate" , "Take away (from value of something)" , "Take away a part of, lower in value" .)