1. What is the Time Given Intensity of Rain Formula?

The Time Given Intensity of Rain formula calculates the time duration based on rainfall intensity using empirical constants. It's derived from intensity-duration-frequency relationships used in hydrology and rainfall analysis.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( T_m \) — Time in minutes
• \( K \) — Empirical constant (mm/hr)
• \( i_{idf} \) — Intensity of rain (mm/hr)
• \( b_{5-20} \) — Empirical constant for time varying between 5-20 minutes

Explanation: The formula establishes the relationship between rainfall intensity and duration using empirical constants derived from rainfall data analysis.

3. Importance of Time Calculation

Details: Accurate time calculation based on rainfall intensity is crucial for hydrological modeling, drainage system design, flood prediction, and water resource management.

4. Using the Calculator

Tips: Enter K constant in mm/hr, rainfall intensity in mm/hr, and constant b in minutes. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for K constant?
A: K constant values typically range from 20-100 mm/hr depending on geographical location and climate conditions.

Q2: How is rainfall intensity measured?
A: Rainfall intensity is typically measured using rain gauges and expressed in millimeters per hour (mm/hr).

Q3: What is the significance of the 0.8 exponent?
A: The 0.8 exponent represents the empirical relationship between intensity and duration derived from rainfall data analysis.

Q4: When is this formula most applicable?
A: This formula is most applicable for time durations between 5-20 minutes and is commonly used in urban drainage design.

Q5: Are there limitations to this equation?
A: The equation is empirical and may have limited accuracy outside the specified time range or in regions with different rainfall patterns.