More about related to calculating “recharge of aquifiers”, using swimming pools as a visible analogy.
http://www.theguardian.pe.ca/Opinion/Letter-to-editor/2014-02-20/article-3622240/Leave-pools-out-of-water-debate/1

Leave pools out of water debate
The Guardian letter to the editor
Published on February 20, 2014 

Editor:
Like most regular readers, I have been following with interest, the numerous articles and letters in The Guardian on the issue of deep-water wells. In the headline article of Fridayʼs (February 14) paper, “ No decision made on deep-water wells: Sherry,” there was an assertion attributed to Mr. Bruce Raymond (manager of watershed and subdivision planning for the province), that is worthy of pause and re-examination. Mr. Raymond is quoted, saying, that the rate at which P.E.Iʼs groundwater is replenished every year is “equal to 154 Olympic-sized swimming pools for every square inch of the Island”.
According to Wikipedia, an Olympic-sized swimming pool contains 2.5 million litres of water, with a volume of 88,0000 cubic feet. It is easy to determine that one cubic foot of water would be 144 feet in height on a single square inch of P.E.I. soil. It follows that 88,000 cubic feet would be 2,400 miles high! That is for a single Olympic-sized swimming pool. For 154 pools, this tower of water would reach an amazing 369,600 miles in height, which is 1.5 times further away than the moon. Hmm. That would be one wicked replenishment rate.
According to Island information, however, “the average yearly rainfall is 1125.8 mm and the average yearly snowfall is 318.2 mm” on Prince Edward Island. That translates to approximately 1.5 meters (or 5 feet) of precipitation per year.
Comparing 369,600 miles to 5 feet, we can determine that the Olympic-sized pool reference is out by a factor in excess of 390 million. Clearly, either Mr. Raymond was misunderstood or he misinterpreted the data. Either way, it seems clear — it would be better to simply disregard any future reference to swimming pools.
Mel Gallant,
Charlottetown