1. What is Sum of Ordinates?

Sum of Ordinates refers to the summation of all the ordinates of direct runoff in hydrograph analysis. It represents the total volume of surface runoff over a specific time period.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \Sigma O \) — Sum of Ordinates (m³/s)
• \( AHA \) — Catchment Area for Hydrograph Analysis (m²)
• \( Sr \) — Surface Runoff (m³/s)
• \( \Delta t \) — Time Interval (s)

Explanation: This formula calculates the sum of ordinates by considering the catchment area, surface runoff rate, and time interval, with 0.36 as a conversion factor.

3. Importance of Sum of Ordinates Calculation

Details: Calculating the sum of ordinates is essential in hydrological studies for understanding runoff patterns, designing drainage systems, and managing water resources effectively.

4. Using the Calculator

Tips: Enter catchment area in square meters, surface runoff in cubic meters per second, and time interval in seconds. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the 0.36 factor?
A: The 0.36 factor is a conversion constant that accounts for unit conversions between area, runoff, and time measurements.

Q2: How is surface runoff measured?
A: Surface runoff is typically measured using flow meters, weirs, or calculated from rainfall data and catchment characteristics.

Q3: What time intervals are typically used?
A: Time intervals can vary from minutes to hours depending on the specific hydrological analysis being performed.

Q4: Can this formula be used for any catchment size?
A: Yes, the formula is scalable and can be applied to catchments of various sizes, though accuracy may vary with extreme conditions.

Q5: How does this relate to unit hydrographs?
A: The sum of ordinates is a fundamental component in constructing unit hydrographs, which are used to predict runoff from rainfall events.