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Webster 1913 Edition

Noun.

That which is raised by pumps, or the work done by pumps.

The

pumpage

last year amounted to . . . gallons.

Sci. Amer.

pumpage ‎(countable and uncountable, plural pumpages)

That which is raised by pumps.
The amount of work done by pumps.
- 1962, Arthur John Zeizel, Ground-water resources of Du Page County, Illinois
  A comparison of Silurian dolomite aquifer water-level hydrographs and pumpage graphs indicates that in general water-level decline is directly proportional to pumpage and suggests that recharge balances discharge.