Due to the prolonged drought, Kitch-Kitchy Resevoir (capacity: 1 billion gallons) was completely dry.

Question

Due to the prolonged drought, Kitch-Kitchy Resevoir (capacity: 1 billion gallons) was completely dry.

Suddenly, a major storm hit, drenching the area with 0.5 inches of rain per hour. A 2,000 acre area feeds

directly into Kitch-Kitchy. Assuming no other loss of water (no evaporation, no ground seepage, no run-off,

etc) how many hours can the poor Kitch-Kitchy Resevoir last before it overflows?

Answer 1

Gallon is a unit of volume. Volume = Area*distance. Looking online, the conversion factor for acre*inch to gallon is:

1 acre*inch = 27154.286 gallons

 

You setup dimensional analysis problems as fractions which multiply to cancel units out leaving the desired unit of measure you want.

 

We want time, which we can get using 0.5 in/hr = 0.5 in / 1 hr

multiply by acre to get volume, acre*in rain per hour>

 

(0.5 in / 1 hr) × 2,000 acre area = 1,000 acre*in / 1 hr

 

1 billion gallons = 1×10⁹ gallons

 

1×10⁹ gallon × (1 acre*in / 27154.286 gallon) × (1 hr / 1,000 acre*in) = 36.83 hr