1. What is the Inglis Formula?

The Inglis Formula is an empirical equation used to estimate the peak rate of runoff for fan-shaped catchments, particularly applicable to the Old Bombay region of India. It provides a simplified approach to calculate maximum discharge rates during storm events.

2. How Does the Calculator Work?

The calculator uses the Inglis Formula:

Where:

• \( QI \) — Peak rate of runoff (m³/s)
• \( A_{km} \) — Catchment area (km²)

Explanation: The formula uses a square root relationship between catchment area and peak runoff rate, with a constant factor of 123 derived from empirical data for specific regional conditions.

3. Importance of Peak Runoff Calculation

Details: Accurate estimation of peak runoff rates is crucial for designing drainage systems, flood control structures, and urban infrastructure planning, particularly in regions prone to heavy rainfall and flooding.

4. Using the Calculator

Tips: Enter the catchment area in square kilometers. The value must be positive and greater than zero. The calculator will compute the peak rate of runoff using the Inglis Formula.

5. Frequently Asked Questions (FAQ)

Q1: What types of catchments is the Inglis Formula applicable to?
A: The Inglis Formula is specifically designed for fan-shaped catchments and was developed based on data from the Old Bombay region of India.

Q2: How accurate is the Inglis Formula compared to other methods?
A: The accuracy varies by region and catchment characteristics. It provides reasonable estimates for the specific conditions it was developed for but may need adjustment for other geographical areas.

Q3: What are the limitations of the Inglis Formula?
A: The formula doesn't account for factors like rainfall intensity, soil type, slope, or land use patterns, which can significantly affect runoff rates in different catchments.

Q4: Can this formula be used for large catchment areas?
A: The formula is generally applicable to the range of catchment sizes it was originally developed for. Extreme sizes may produce less reliable results.

Q5: How does this formula compare to modern hydrological models?
A: While modern models incorporate more variables and provide more comprehensive analysis, the Inglis Formula remains useful for quick estimates and preliminary calculations in appropriate contexts.