1. What is Rainfall Intensity for Storms Frequency of 15 Years?

Rainfall Intensity for Storms Frequency of 15 Years is the ratio of the total amount of rain falling during a given period to the duration of the period, specifically considering storm frequency of 15 years. It's a crucial parameter in hydrology and civil engineering for designing drainage systems and flood control structures.

2. How Does the Calculator Work?

The calculator uses the rainfall intensity formula:

Where:

• \( i_{st} \) — Rainfall intensity (mm/hr)
• \( K_{s15} \) — Empirical constant for 15-year storm frequency (mm/hr)
• \( T_m \) — Time duration (minutes)

Explanation: The formula calculates rainfall intensity based on the empirical constant and time duration, with the exponent 0.65 representing the non-linear relationship between rainfall intensity and duration.

3. Importance of Rainfall Intensity Calculation

Details: Accurate rainfall intensity calculation is essential for designing stormwater drainage systems, sizing culverts and pipes, planning flood control measures, and assessing flood risks in urban and rural areas.

4. Using the Calculator

Tips: Enter the K constant value in mm/hr and time duration in minutes. Both values must be positive numbers. The K constant is specific to the 15-year storm frequency and varies by geographical location.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the 15-year storm frequency?
A: A 15-year storm frequency represents a rainfall event that has a 1 in 15 chance of occurring in any given year, used for designing infrastructure with moderate risk tolerance.

Q2: How is the K constant determined for different locations?
A: The K constant is derived from historical rainfall data analysis and varies by geographical region, typically provided by meteorological agencies or hydrological studies.

Q3: Why is time duration important in rainfall intensity calculation?
A: Rainfall intensity decreases as duration increases due to the nature of storm patterns. Shorter durations typically have higher intensities.

Q4: What are typical applications of this calculation?
A: This calculation is used in designing stormwater management systems, sizing drainage pipes, planning flood control structures, and conducting hydrological studies.

Q5: Are there limitations to this formula?
A: This empirical formula provides estimates and may need adjustment for specific local conditions, extreme weather events, or unusual topography.