1. What is Peak Discharge of D-h Unit Hydrograph?

The peak discharge of a D-h unit hydrograph represents the maximum volume flow rate displayed in a unit hydrograph. It is a crucial parameter in hydrology for predicting flood peaks and designing drainage systems.

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)

Explanation: This empirical formula relates the peak discharge directly to the catchment area raised to the power of 3/4, with a constant coefficient of 1.79.

3. Importance of Peak Discharge Calculation

Details: Accurate peak discharge estimation is essential for flood forecasting, hydraulic structure design, watershed management, and environmental impact assessments.

4. Using the Calculator

Tips: Enter the catchment area in square meters. The value must be positive and greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a unit hydrograph?
A: A unit hydrograph represents the direct runoff response of a watershed to a unit depth of excess rainfall distributed uniformly over the drainage area.

Q2: Why is the exponent 3/4 used in the formula?
A: The 3/4 exponent is derived from empirical studies and represents the non-linear relationship between catchment area and peak discharge.

Q3: What are typical values for peak discharge?
A: Peak discharge values vary significantly based on catchment characteristics, ranging from small values for small areas to very large values for extensive watersheds.

Q4: Are there limitations to this formula?
A: This is an empirical formula and may not account for all catchment characteristics such as slope, soil type, land use, and rainfall intensity patterns.

Q5: When should this formula be used?
A: This formula is particularly useful for preliminary estimates and in situations where detailed hydrological data is not available.