免费降雨强度计算器
计算设计暴雨强度，用于排水系统设计。
Rainfall Intensity
100.0 mm/h
Rainfall Intensity vs Storm Duration
公式
## Rainfall Intensity Rainfall intensity is the rate of rainfall, critical for sizing stormwater drainage systems. ### Formula **i = P / t** where P is the total depth of rainfall (mm) and t is the duration (hours). Shorter, more intense storms require higher drainage capacity. Design storms are typically characterised by intensity-duration-frequency (IDF) curves.
计算示例
50 mm of rain over 30 minutes.
- 01Duration in hours = 30 / 60 = 0.5 h
- 02Intensity = 50 / 0.5 = 100 mm/h
- 03This is a relatively intense rainfall event.
常见问题
What is a design storm?
A design storm has a specific return period (e.g., 1-in-10-year, 1-in-100-year) that defines its intensity for a given duration. Higher return periods mean more intense but rarer storms. Minor drainage uses 2-10 year storms; major drainage uses 50-100 year storms.
What duration should I use?
Use the time of concentration (tc) of the catchment as the storm duration. tc is the time for water to travel from the most remote point to the design point. This gives the peak runoff rate from the rational method.
Where do I find IDF data?
Local meteorological agencies or hydrology offices publish IDF curves based on historical rainfall records. In the US, NOAA Atlas 14 provides detailed IDF data for any location.
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