1. What is the Peak Discharge Formula?

The formula calculates the peak discharge of a D-h Unit hydrograph using the catchment area and weighted mean slope. This is particularly useful for hydrological analysis and flood prediction in watersheds with gentle slopes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q_{pd} \) — Peak discharge of D-h Unit hydrograph (m³/s)
• \( A \) — Area of Catchment (m²)
• \( S_m \) — Weighted Mean Slope (unitless)

Note: This formula is specifically designed for weighted mean slopes less than or equal to 0.0028.

3. Importance of Peak Discharge Calculation

Details: Accurate peak discharge estimation is crucial for designing hydraulic structures, flood forecasting, and watershed management. It helps in determining the maximum flow rate that a watershed can produce during a storm event.

4. Using the Calculator

Tips: Enter the catchment area in square meters and the weighted mean slope (must be ≤ 0.0028). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a D-h Unit Hydrograph?
A: A D-h Unit Hydrograph represents the direct runoff response of a watershed to a unit depth of excess rainfall occurring uniformly over the watershed for a specified duration.

Q2: Why is the slope limited to 0.0028?
A: This formula is specifically calibrated for gentle slopes. Different formulas may be required for steeper slopes to ensure accurate predictions.

Q3: What units should be used for input values?
A: Area should be in square meters, and slope should be a dimensionless ratio (rise over run).

Q4: How accurate is this formula?
A: The formula provides a good estimate for gentle slope conditions but should be validated with field measurements for critical applications.

Q5: Can this formula be used for large catchment areas?
A: Yes, the formula scales appropriately with catchment area, but proper validation is recommended for very large watersheds.