Thanks to Prof. Steven Businger with the University of Hawai‘i at Mānoa Department of Meteorology, I've been spending some quality time with the seven-day totals of all the rain gauges in Hawai‘i from Tuesday, March 10, to Monday, March 16.
These gauges should be measured in cats and dogs, but in reality they use inches. The wettest place in the Islands was a gauge on Maui, which measured nearly 50 inches of rain.
One can calculate the total amount water with a few tools and figures. The U.S. Geological Survey has a handy rainfall calculator.
All you need is the land area in question and the gauge reading. For the following calculations, I used the nearest inch measurement that tool permitted.
Land areas for the Islands come from DBEDT.
To keep the math simple, I averaged the amount of rainfall for all the gauges on each island, so consider this a rough approximation despite all the long numbers.
Ready? Put on your raincoat!
Hawai‘i Island, with a land area of 4,028.4 square miles, with 53 rain gauges reporting an average reading of 15.26 inches, received 1,050,116,866,560 gallons.
That's a trillion gallons.
Maui, with a land area 727 square miles, having 29 gauges with an average reading of 18.71 inches — the nearest the calculator allowed was 20 inches — received 252,684,262,400 gallons. That's about 253 billion gallons.
O‘ahu, with a land area of 600.6 square miles, having 44 gauges with an average reading of 13.52 inches — for this one the calculator gave me a choice of 12 or 15 inches, I went with 15 — received 156,563,447,040 gallons. More simply, nearly 157 billion gallons.
Kaua‘i, land area of 619.9 square miles, 24 gauges with an average reading 11.12 inches — I selected 10 inches from the calculator — received 107,729,693,440 gallons, or nearly 108 billion gallons.
Molokai, land area of 260 square miles, having six gauges with an average reading 12.92 inches — I chose 12 inches in the calculator— received 54,221,107,200 gallons, or 54 billion.
Lānaʻi, 140.5 square miles, just three gauges with an average reading 10.34 inches — I used 10 in the calculator — received 24,416,876,800 gallons, or about 24 billion.
The total across these six islands works out 1.65 trillion gallons falling over a week.
How does that compare to how much fresh water we use?
The Hawai‘i State Data Book says the state consumes 683 million gallons of fresh water per day, from ground and surface sources.
In about one week, the Islands received the equivalent just over 2,400 days worth of freshwater. More than six and half year's worth.
A. Kam Napier is editor in chief of Aloha State Daily. His opinions in Pipikaula Corner are his own and not reflective of the ASD team.
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A. Kam Napier can be reached at kam@alohastatedaily.com.
