Saturday Teaser Curio #77: Rain, Rain, Go away...

Here in California (home of Curious HQ), we went from an extended multi-year drought to one of the wettest winters on record. Reservoirs and streams are overflowing, triggering floods and forced evacuations. Of course, the best way to wait out a storm is a rain-themed teaser, so here we go.

Due to the prolonged drought, Kitch-Kitchy Reservoir (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 Reservoir last before it overflows?

Ready for the answer?

Actually, you can Google around for almost all of this, but we're going to start with the area of an acre.

• 1 acre = 43,560 sq ft
• 0.5 inches = 1/24 ft
• Multiply those by 2,000 acres = 3,630,000 cu ft of rain per hour

Google also tells us that 1 cu ft of water is 7.48052 gallons, so that's equal to:

• 27,154,287.60 gallons of rain per hour

Divide that into the capacity of the Kitch-Kitchy Reservoir, and you get your answer: ~36.8 hours.