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

The formula calculates the peak discharge of a D-h unit hydrograph based on the catchment area and lag time of a 1-hour unit hydrograph. This is essential in hydrological engineering for flood prediction and water resource management.

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)
• \( T_{p1} \) — Lag time of a 1-h unit hydrograph (hours)

Explanation: The formula establishes a relationship between catchment area, lag time, and the resulting peak discharge in a unit hydrograph system.

3. Importance of Peak Discharge Calculation

Details: Accurate peak discharge estimation is crucial for designing hydraulic structures, flood forecasting, and watershed management planning.

4. Using the Calculator

Tips: Enter catchment area in square meters and lag time in hours. Both values must be positive numbers greater than zero.

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 over a specific duration.

Q2: How is lag time determined?
A: Lag time is typically determined from rainfall-runoff data analysis or using empirical formulas based on watershed characteristics.

Q3: What are typical values for peak discharge?
A: Peak discharge values vary widely depending on catchment size, topography, soil type, and rainfall intensity.

Q4: Are there limitations to this formula?
A: This formula provides an estimation and may need adjustment based on specific watershed characteristics and local conditions.

Q5: Can this be used for urban drainage design?
A: While useful for preliminary estimates, urban drainage design often requires more detailed hydraulic modeling.