Home
Back
Parker's Formula:
| From: | To: |
Parker's Formula is an empirical equation used to estimate runoff depth from rainfall in the British Isles. It provides a simplified method for calculating the portion of precipitation that becomes surface runoff rather than being absorbed into the ground.
The calculator uses Parker's Formula:
Where:
Explanation: The formula calculates runoff depth by multiplying rainfall depth by 0.94 and subtracting 14 inches, representing the portion of rainfall that becomes surface runoff.
Details: Accurate runoff estimation is crucial for flood prediction, water resource management, drainage system design, and environmental impact assessments in the British Isles region.
Tips: Enter rainfall depth in inches. The value must be valid (greater than 0). The calculator will compute the corresponding runoff depth using Parker's Formula.
Q1: What is the application range of Parker's Formula?
A: Parker's Formula is specifically designed for catchment areas in the British Isles and may not be accurate for other geographical regions.
Q2: Why subtract 14 inches in the formula?
A: The subtraction represents the initial abstraction and infiltration losses that occur before runoff begins in typical British Isles catchment conditions.
Q3: What are typical runoff coefficients for the British Isles?
A: Runoff coefficients vary by soil type, land use, and rainfall intensity, but typically range from 0.3 to 0.8 in urban areas and 0.1 to 0.5 in rural areas.
Q4: When is this formula most accurate?
A: The formula works best for moderate rainfall events and typical catchment conditions found throughout the British Isles.
Q5: Are there limitations to this formula?
A: The formula may be less accurate for extreme rainfall events, frozen ground conditions, or catchments with unusual soil or land use characteristics.