Gravity Pipe Flow Calculator [cracked] -

$$Q = \frac1.490.009 \times 0.196 \times (0.125)^2/3 \times (0.03)^1/2$$ $$Q \approx 165.5 \times 0.196 \times 0.25 \times 0.173$$ $$Q \approx 1.4 \text cubic feet per second (cfs)$$

Converted to Gallons Per Minute (GPM): $$1.4 \times 448.83 \approx \mathbf628 \text GPM$$

For critical applications (e.g., hospital drainage, major culverts), use a hydraulic modeling software like HEC‑RAS or EPA SWMM, not a simple calculator.

| Input | Description | Example | |-------|-------------|---------| | | Inside diameter | 12 inches (or 300 mm) | | Pipe slope | Rise over run | 1% (0.01 ft/ft) | | Manning's n | Pipe roughness | Concrete: 0.013, PVC: 0.009, Corrugated metal: 0.024 | | Flow depth ratio | Depth / Diameter (0 to 1) | 0.75 (75% full) |