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Stormwater Volume Formula:
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Stormwater volume calculation estimates the amount of runoff water generated from rainfall over a specific area, considering the surface's runoff characteristics. This is essential for designing drainage systems and managing stormwater.
The calculator uses the stormwater volume formula:
Where:
Explanation: The formula calculates the total volume of water that runs off a surface rather than being absorbed, based on rainfall amount and surface characteristics.
Details: Accurate stormwater volume calculation is crucial for designing effective drainage systems, preventing flooding, managing water resources, and meeting environmental regulations.
Tips: Enter rainfall in meters, area in square meters, and runoff coefficient (0-1). All values must be positive numbers with rainfall and area > 0, coefficient between 0-1.
Q1: What is a typical runoff coefficient value?
A: Runoff coefficients vary by surface type: paved surfaces (0.8-0.95), lawns (0.05-0.35), forests (0.01-0.20). The value represents the fraction of rainfall that becomes runoff.
Q2: Why convert rainfall to meters?
A: Using consistent SI units (meters for length/depth, square meters for area) ensures volume calculation in cubic meters, the standard unit for water volume measurement.
Q3: How does surface slope affect runoff?
A: Steeper slopes generally increase runoff coefficients as water runs off more quickly rather than being absorbed into the surface.
Q4: Can this be used for large catchment areas?
A: Yes, the formula scales for any size area, though very large areas may require consideration of rainfall distribution variations across the catchment.
Q5: What about evaporation and infiltration losses?
A: These are accounted for in the runoff coefficient, which represents the net fraction of rainfall that becomes measurable runoff after accounting for losses.