Question 1066843
Number of sq ft =5280 ft^2/mile*5280 ft^2/mile*589 sq miles=1.642 x 10^10
multiply by (1/12) for cubic feet since 1 inch of rain=1368364800 ft^3
62.4/(25/3)= number of gallons per cubic foot, so have 1.0246 x 10^10 gallons.

For rainwater harvesting, use 1000 ft^2 roof * 1 inch of rain, or 83.3333 ft^3 of water
 62.4/(25/3) pounds/cubic foot/gallons=7.488 gallons per cubic foot, and that product, 624, is the number of gallons per 1000 ft^3 for an inch of rain.

x*(5280*5280*A)*62.4/[12*(25/3)]=N; x=inches of rain.