Fund artist needing endless help for exhibition, ultimately (9)

I believe the answer is:

reservoir

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'fund' is the definition.
(thesaurus)

I cannot understand how the rest of the clue works.

(Other definitions for reservoir that I've seen before include "Large water store" , "water over a wide area?" , "Man-made lake to store water" , "Artificial lake" , "Area flooded" .)

I've seen this clue in The Telegraph.

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