1. What is the Catchment Area Formula?

The formula calculates the area of catchment based on the peak discharge of a D-h unit hydrograph and the lag time of a 1-h unit hydrograph. It provides an estimation of the geographical area from which water flows into a particular point.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( A \) — Area of Catchment (m²)
• \( Q_{pd} \) — Peak discharge of a D-h Unit hydrograph (m³/s)
• \( T_{p1} \) — Lag Time of a 1-h Unit Hydrograph (hours)

Explanation: The formula accounts for the relationship between peak discharge, lag time, and catchment area in hydrological analysis.

3. Importance of Catchment Area Calculation

Details: Accurate catchment area estimation is crucial for water resource management, flood prediction, and hydrological modeling. It helps in understanding water flow patterns and designing appropriate water management systems.

4. Using the Calculator

Tips: Enter peak discharge in m³/s and lag time in hours. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a unit hydrograph?
A: A unit hydrograph represents the direct runoff response of a catchment to a unit depth of excess rainfall over a specific duration.

Q2: How is lag time defined?
A: Lag time is the time interval from the midpoint of the rainfall excess to the peak discharge in the hydrograph.

Q3: What factors affect catchment area calculations?
A: Topography, soil type, land use, and rainfall characteristics can all influence catchment area calculations.

Q4: When is this formula most applicable?
A: This formula is particularly useful for hydrological modeling and flood prediction in medium to large catchments.

Q5: Are there limitations to this equation?
A: The formula may be less accurate for very small or very large catchments, or in areas with unusual hydrological characteristics.