1. What is Stormwater Runoff Volume?

Stormwater runoff volume is the amount of water that flows over the land surface during and immediately after rainfall events. It's calculated based on rainfall intensity and the area of the surface where the rain falls.

2. How Does the Calculator Work?

The calculator uses the stormwater runoff volume equation:

Where:

• \( Rainfall \) — Rainfall depth (inches)
• \( Area \) — Drainage area (acres)
• \( 3630 \) — Conversion factor (cubic feet per acre-inch)

Explanation: The equation converts rainfall depth over a given area into total volume of water runoff.

3. Importance of Runoff Calculation

Details: Calculating stormwater runoff is essential for designing drainage systems, assessing flood risks, and planning stormwater management infrastructure.

4. Using the Calculator

Tips: Enter the property address, rainfall amount in inches, and area in acres. The calculator will determine the total volume of stormwater runoff in cubic feet.

5. Frequently Asked Questions (FAQ)

Q1: Why is the conversion factor 3630?
A: 3630 is the number of cubic feet in an acre-inch (1 acre-inch = 3630 cubic feet), which converts the units from acre-inches to cubic feet.

Q2: How accurate is this calculation?
A: This provides a basic estimate. Actual runoff may vary based on soil type, slope, land cover, and other factors.

Q3: What's a typical rainfall value to use?
A: For design purposes, use local rainfall intensity data for specific storm durations and return periods.

Q4: Can I use this for large areas?
A: The calculation works for any size area, but for very large areas, more sophisticated modeling may be needed.

Q5: How can I reduce stormwater runoff?
A: Techniques include permeable pavements, rain gardens, green roofs, and rainwater harvesting systems.