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Calcimator

Infiltration Rate Calculator

Calculate soil infiltration rate using Horton's equation. Determine average rate, total infiltration, and runoff potential from field measurements.

Inputs

in/hr
in/hr
minutes

Results

Average Infiltration Rate

1.29 in/hr

Total Infiltration

1.29 inches

Soil TypeSilt Loam
Typical Range0.2–1.5
AssessmentNormal for soil type
Runoff PotentialModerate
How to Use This Calculator
  1. Conduct a double-ring infiltrometer test and enter the final steady-state infiltration rate in inches per hour.
  2. Input your soil texture class and organic matter percentage.
  3. Set the current land use and any known compaction history.
  4. Review the Infiltration Class and the Runoff Risk rating.
  5. Use the Management Improvement Potential to quantify gains from cover crops or reduced tillage.

How the result changes with Initial Infiltration Rate

Initial Infiltration RateAverage Infiltration RateTotal Infiltration
2.010.98 in/hr0.98 inches
7.012.56 in/hr2.56 inches
134.46 in/hr4.46 inches
186.04 in/hr6.04 inches

What each input means

Initial Infiltration Rate
Infiltration rate at the start of measurement (time zero). This is the highest rate before soil saturation.
Final (Steady-State) Rate
Steady-state infiltration rate after the soil reaches equilibrium. Measured after rate stops decreasing.
Test Duration
Total duration of the infiltration test in minutes. Standard ring tests run 60–120 minutes.
Soil Type
General soil texture for comparison: 1 = Sandy, 2 = Silt Loam, 3 = Clay.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Initial Infiltration Rate = 3, Final (Steady-State) Rate = 0.5, Test Duration = 60, Soil Type = 2 = 4 input(s) provided
  2. Calculate Average Infiltration Rate
    1.29 = 1.29
  3. Calculate Total Infiltration
    1.29 = 1.29
  4. Calculate Soil Type
    Soil Type = soil.name
    Silt Loam = Silt Loam
  5. Calculate Typical Range
    0.2–1.5 = 0.2–1.5

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