径流系数计算器 — 公式
## Rational Method for Stormwater Runoff
The Rational Method is the most widely used formula for estimating peak runoff from small catchments.
### Formula
**Q = C i A / 360**
where Q is peak flow in m^3/s, C is the runoff coefficient (0 to 1), i is rainfall intensity in mm/h, and A is catchment area in hectares. The factor 360 converts units. This method assumes the entire catchment contributes to runoff when storm duration equals the time of concentration.
The Rational Method is the most widely used formula for estimating peak runoff from small catchments.
### Formula
**Q = C i A / 360**
where Q is peak flow in m^3/s, C is the runoff coefficient (0 to 1), i is rainfall intensity in mm/h, and A is catchment area in hectares. The factor 360 converts units. This method assumes the entire catchment contributes to runoff when storm duration equals the time of concentration.
计算示例
5 hectare urban catchment, C=0.6, 100 mm/h intensity.
- Q = 0.6 x 100 x 5 / 360 = 300/360 = 0.833 m^3/s
- Q = 833 L/s