How does the Stormwater Runoff Calculator work?

Use rational method: Q = C×I×A where C is runoff coefficient, I is rainfall intensity, A is area Then: C varies by surface: impervious (0.8-0.95), pervious (0.1-0.3) Then: Results show peak flow for design storm.

Can you give an example of how to use the Stormwater Runoff Calculator?

Example: Input Area 10 ha, 60% impervious, rainfall 100 mm/hr gives a result of Q ≈ 1.8 m³/s peak flow (For drainage system sizing).

Is the Stormwater Runoff Calculator free to use?

Yes — completely free with no registration, download, or subscription required. All calculations happen instantly in your browser.

How accurate is the Stormwater Runoff Calculator?

Our Stormwater Runoff Calculator uses verified mathematical formulas and is accurate to multiple decimal places. Results are calculated in real-time using the same methods used by professionals.

Specialized

Stormwater Runoff Calculator

Runoff Coefficient (C)

Rainfall Intensity (in/hr)

Drainage Area (acres)

Stormwater runoff volume is calculated using rainfall and surface area characteristics. It's essential for drainage system design.

Symbol	Name	Unit	Description
Q	C×I×A where C is runoff coefficient	—	C×I×A where C is runoff coefficient
C	C value	—	Variable used in the calculation
I	I value	—	Variable used in the calculation
A	A value	—	Variable used in the calculation

Difficulty:intermediate

References

›Stormwater Runoff — Wikipedia

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Stormwater Runoff Calculator

Stormwater Runoff Calculator

What is Stormwater Runoff Calculator?

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