An enigmatic reference explained

In a recent post I happened to mention Archimedes (c.287 BCE - c.212 BCE), after which Yorkshire Pudding commented, 'I was puzzled by your enigmatic reference to a "water screw". Please explain.'

Here is what I was referring to:

(Illustration from Chambers's Encyclopedia (Philadelphia: J. B. Lippincott Company, 1875)

Its purpose is to lift water from a lower level to a higher level, usually for irrigation of land, and it operates on the following principle:

(Animated diagram created by Silberwolf, published 6 May 2007, and used in accordance with CC-BY-SA-2.5)

Why Silberwolf would use a red sphere to represent water, now that's what I find enigmatic. Nearly eight decades ago the motion picture How Green Was My Valley won many awards.

Perhaps Mr. or Ms. Silberwolf's motion picture should be called How Red Was My Canal.