1. What is Barlow's Formula?

Barlow's Formula estimates runoff in flat cultivated and absorbent soils with continuous downpour conditions. It provides a simplified approach to calculate runoff based on rainfall measurements.

2. How Does the Calculator Work?

The calculator uses Barlow's formula:

Where:

• \( R \) — Runoff (cm)
• \( P \) — Rainfall (cm)

Explanation: The formula assumes that 15% of the total rainfall becomes runoff in flat cultivated and absorbent soil conditions with continuous downpour.

3. Importance of Runoff Calculation

Details: Accurate runoff estimation is crucial for water resource management, flood prediction, irrigation planning, and soil conservation in agricultural areas.

4. Using the Calculator

Tips: Enter total rainfall in centimeters. The value must be valid (rainfall > 0). The calculator will compute the estimated runoff.

5. Frequently Asked Questions (FAQ)

Q1: What types of soil does this formula apply to?
A: This formula is specifically designed for flat cultivated and absorbent soils under continuous downpour conditions.

Q2: Why is the coefficient 0.15 used?
A: The 0.15 coefficient represents the empirical finding that approximately 15% of rainfall becomes runoff in these specific soil and rainfall conditions.

Q3: How accurate is this formula?
A: The formula provides a reasonable estimate for the specified conditions but may vary based on specific soil properties, vegetation cover, and rainfall intensity.

Q4: Can this formula be used for sloped terrain?
A: No, this formula is specifically designed for flat cultivated areas. Different formulas should be used for sloped terrain.

Q5: What are typical runoff values?
A: Runoff values typically range from 5-30% of total rainfall depending on soil type, slope, vegetation, and rainfall characteristics.