Healthful water filling trench? Hurry (8)

I believe the answer is:

dispatch

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'hurry' is the definition.
(thesaurus)

'healthful water filling trench?' is the wordplay.
'healthful water' becomes 'spa' (I've seen this before. I am not sure about the 'healthful' bit.).
'filling' is an insertion indicator.
'trench?' becomes 'ditch' ('ditch' can be a synonym of 'trench').
'spa' going within 'ditch' is 'DISPATCH'.

Can you help me to learn more?

(Other definitions for dispatch that I've seen before include "Sort of rider" , "Execute" , "alacrity" , "Kill, send off" , "making killing" .)

I've seen this clue in The Independent.

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