1. What is the Retention Pond Volume Calculation?

The retention pond volume calculation determines the required storage capacity for stormwater management. It calculates the volume needed to temporarily hold runoff water during rainfall events, allowing for controlled release and preventing flooding.

2. How Does the Calculator Work?

The calculator uses the retention pond volume formula:

Where:

• \( C \) — Runoff coefficient (dimensionless)
• \( P \) — Rainfall depth (inches)
• \( A \) — Drainage area (square feet)
• 7.48 — Conversion factor (cubic feet to gallons)
• 12 — Conversion factor (inches to feet)

Explanation: The formula calculates runoff volume by multiplying the drainage area by rainfall depth and runoff coefficient, then converts to gallons for practical use.

3. Importance of Retention Pond Sizing

Details: Proper retention pond sizing is crucial for effective stormwater management, flood prevention, water quality improvement, and compliance with environmental regulations.

4. Using the Calculator

Tips: Enter runoff coefficient (typically 0.2-0.95 based on surface type), rainfall depth for design storm, and drainage area. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical runoff coefficient values?
A: Pavement: 0.8-0.95, Lawns: 0.05-0.35, Forests: 0.01-0.20, depending on slope and soil type.

Q2: How to determine design rainfall depth?
A: Use local rainfall data for specific storm return periods (e.g., 10-year, 25-year storm events).

Q3: What's the difference between detention and retention ponds?
A: Detention ponds temporarily hold water and release it, while retention ponds maintain a permanent pool of water.

Q4: Are there safety factors to consider?
A: Yes, include factors for sediment accumulation, climate change impacts, and unexpected rainfall intensities.

Q5: What regulations govern retention pond design?
A: Local municipal codes, state environmental regulations, and sometimes federal requirements for water quality.