Soil Infiltration Rate Calculator
Enter the total depth of water applied during the test.
Enter the total time taken for the water to infiltrate.
Calculation Results
Infiltration Rate: 0 mm/hour
Understanding Soil Infiltration Rates
The infiltration rate is a critical measure in hydrology and agricultural science that determines how quickly water enters the soil profile. Understanding this rate is essential for designing efficient irrigation systems, managing stormwater runoff, and preventing soil erosion. This calculator uses the depth-over-time method to provide an hourly infiltration capacity.
The Formula for Infiltration
To calculate the rate, we use the following mathematical expression:
Infiltration Rate (mm/hr) = (Depth of Water in mm / Time in Minutes) × 60
Typical Infiltration Rates by Soil Type
Soil texture is the primary driver of infiltration. Below is a reference table for expected steady-state infiltration rates:
| Soil Type | Infiltration Rate (mm/hr) |
|---|---|
| Sand | > 30 mm/hr |
| Sandy Loam | 20 – 30 mm/hr |
| Loam | 10 – 20 mm/hr |
| Clay Loam | 5 – 10 mm/hr |
| Clay | 1 – 5 mm/hr |
Factors Affecting Infiltration
- Soil Texture: Larger particles like sand have larger pores, allowing faster water movement.
- Compaction: High traffic or heavy machinery reduces pore space, drastically lowering the infiltration rate.
- Organic Matter: High organic content improves soil structure and increases the rate of absorption.
- Initial Moisture: Wet soil absorbs water more slowly than dry soil because the capillary forces are weaker.
- Vegetation Cover: Plants protect the soil surface from the impact of raindrops, preventing "crusting" which inhibits infiltration.
How to Conduct a Field Test
- Setup: Use a double-ring infiltrometer or a simple cylinder driven 10-15cm into the ground.
- Saturation: Pre-wet the soil to ensure you are measuring the steady-state rate.
- Measurement: Pour a measured depth of water (e.g., 50mm) into the cylinder.
- Timing: Use a stopwatch to record how many minutes it takes for the water to disappear completely.
- Calculation: Use the calculator above to find your mm/hr value.