Maximum Rainfall Intensity Given Peak Rate of Runoff Calculator

Burkli Zeigler Formula:

\[ I_{BZ} = \frac{455 \times Q_{BZ}}{K' \times \sqrt{S_o \times A_D}} \]

Peak Rate of Runoff (Q_BZ):

m³/s

Runoff Coefficient (K'):

Slope of the Ground (S_o):

Drainage Area (A_D):

hectare

Maximum Rainfall Intensity (I_BZ):

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1. What is the Burkli Zeigler Formula?

The Burkli Zeigler formula is used to calculate the maximum rainfall intensity based on peak runoff rate, runoff coefficient, ground slope, and drainage area. It's particularly useful in hydrological studies and urban drainage system design.

2. How Does the Calculator Work?

The calculator uses the Burkli Zeigler formula:

\[ I_{BZ} = \frac{455 \times Q_{BZ}}{K' \times \sqrt{S_o \times A_D}} \]

Where:

\( I_{BZ} \) — Maximum rainfall intensity (cm/hr)
\( Q_{BZ} \) — Peak rate of runoff (m³/s)
\( K' \) — Runoff coefficient (dimensionless)
\( S_o \) — Slope of the ground
\( A_D \) — Drainage area (hectare)

Explanation: The formula calculates the rainfall intensity that would produce the given peak runoff rate, considering the watershed characteristics.

3. Importance of Maximum Rainfall Intensity Calculation

Details: Accurate rainfall intensity estimation is crucial for designing drainage systems, flood forecasting, and urban planning to prevent waterlogging and flooding.

4. Using the Calculator

Tips: Enter peak runoff rate in m³/s, runoff coefficient (typically between 0-1), ground slope, and drainage area in hectares. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical runoff coefficient value?
A: Runoff coefficients vary from 0.1-0.2 for forested areas to 0.8-0.9 for paved urban areas, depending on surface permeability.

Q2: How is ground slope measured?
A: Ground slope is typically measured as the vertical rise divided by horizontal distance, often expressed as a percentage or ratio.

Q3: What factors affect runoff coefficient?
A: Surface type, soil permeability, vegetation cover, antecedent moisture conditions, and rainfall intensity all affect runoff coefficient values.

Q4: When is this formula most applicable?
A: The Burkli Zeigler formula is particularly useful for small to medium-sized urban watersheds with relatively uniform characteristics.

Q5: Are there limitations to this formula?
A: The formula assumes uniform rainfall distribution and may not be accurate for very large watersheds or complex terrain conditions.