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Rainfall Calculation Formula:
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A Rainfall Calculator In Gallons estimates the volume of rainwater collected from a specific area during a rainfall event. It helps in planning water conservation systems, irrigation needs, and understanding water collection potential.
The calculator uses the following formula:
Where:
Explanation: The formula converts the two-dimensional rainfall measurement (depth) into a three-dimensional volume measurement (gallons) based on the collection area.
Details: Calculating rainfall volume is essential for designing rainwater harvesting systems, understanding stormwater runoff, planning irrigation, and assessing water conservation potential.
Tips: Enter the collection area in square feet and rainfall amount in inches. Both values must be positive numbers. The calculator will estimate the total gallons of rainwater collected.
Q1: How accurate is this calculator?
A: It provides a theoretical maximum based on perfect collection. Real-world collection will be slightly less due to evaporation, absorption, and system inefficiencies.
Q2: Can I use this for any surface area?
A: Yes, as long as you know the area in square feet. This could be a roof, parking lot, or any other impervious surface.
Q3: Why is the conversion factor 0.623?
A: This comes from the fact that 1 inch of rain on 1 square foot equals approximately 0.623 gallons (1 cubic foot = 7.48052 gallons, and 1 inch = 1/12 foot).
Q4: How can I use this for rainwater harvesting?
A: The calculation helps size your storage tanks by showing how much water you can expect to collect from your roof or other collection surface during rainfall events.
Q5: Does this account for multiple rainfall events?
A: No, this calculates for a single rainfall event. For annual estimates, you would need to know the average annual rainfall and multiply accordingly.