1. What is the Rainfall Depth Formula?

The Rainfall Depth formula calculates the amount of rainfall based on runoff depth and runoff coefficient. It provides an estimation of precipitation that would result in a specific amount of surface runoff.

2. How Does the Calculator Work?

The calculator uses the Rainfall Depth formula:

Where:

• \( P_{cm} \) — Rainfall Depth (cm)
• \( R \) — Runoff Depth (cm)
• \( C_r \) — Runoff Coefficient (dimensionless)

Explanation: The formula calculates rainfall depth by dividing the measured runoff depth by the runoff coefficient, which represents the proportion of rainfall that becomes surface runoff.

3. Importance of Rainfall Depth Calculation

Details: Accurate rainfall depth estimation is crucial for hydrology studies, flood prediction, water resource management, and designing drainage systems and irrigation infrastructure.

4. Using the Calculator

Tips: Enter runoff depth in centimeters and runoff coefficient as a decimal between 0 and 1. Both values must be valid (runoff depth > 0, runoff coefficient > 0 and ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical range for runoff coefficients?
A: Runoff coefficients typically range from 0.05 (permeable surfaces like lawns) to 0.95 (impervious surfaces like concrete).

Q2: How is runoff depth measured?
A: Runoff depth is typically measured using flow meters, weirs, or by collecting and measuring runoff water volume over a known area.

Q3: What factors affect runoff coefficient?
A: Soil type, slope, land cover, rainfall intensity, and antecedent moisture conditions all influence the runoff coefficient.

Q4: When is this calculation most useful?
A: This calculation is particularly useful for urban planning, agricultural water management, and environmental impact assessments.

Q5: Are there limitations to this formula?
A: The formula assumes uniform rainfall distribution and doesn't account for infiltration rates, evaporation, or temporal variations in rainfall intensity.