Description
Return a supplied two-term infiltration-depth approximation.
Infiltration and capillary models describe water movement under specific geometry and boundary assumptions. A square-root-time contribution, ponding boundary or ideal cylindrical-pore rise is a local model term; it does not fit soil parameters or establish a whole profile’s hydraulic behavior. Units of time and length must remain compatible throughout.
Return a supplied two-term infiltration-depth approximation.
When to use this tool
Use Infiltration Sorptivity Square Time Term when checking the stated limited infiltration or ideal capillary term.
How to use the tool and how it works
- Enter sorptivity, conductivity, elapsed. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read cumulativeDepth. Use the output convention below.
Return a supplied two-term infiltration-depth approximation. Require sorptivity, conductivity and elapsed >= 0; cumulativeDepth = sorptivity*sqrt(elapsed)+conductivity*elapsed.1
A two-term infiltration approximation combines square-root-time and linear-time contributions. Its validity and coefficients require hydraulic and boundary assumptions; this helper simply evaluates the supplied terms.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| sorptivity | Length/sqrt(time), using the same time unit as elapsed. | Required. Finite number; minimum 0. |
| conductivity | Supplied coefficient in length/time for the linear term; not automatically a validated saturated conductivity. | Required. Finite number; minimum 0. |
| elapsed | Elapsed | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| cumulativeDepth | sorptivity*sqrt(elapsed)+conductivity*elapsed in the compatible length unit. | Required. Finite number. |
{
"input": {
"sorptivity": 2,
"conductivity": 0.5,
"elapsed": 4
},
"output": {
"cumulativeDepth": 6
}
}Limitations and assumptions
- Sorptivity has length/sqrt(time) units and the linear-time coefficient length/time; no complete Richards solution, coefficient fit or universal saturated-conductivity equivalence is established.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use measured hydraulic properties and the appropriate complete infiltration/retention model, including boundary conditions and validity regime, for field predictions.
References
-
Calculation and input contract: agrophysics/infiltration-sorptivity-square-time-term — tool.io
-
Infiltration Models: Philip’s Two-Term Model — US Environmental Protection Agency
Similar or alternative tools
- Infiltration Ponding Time Boundary
Classify time relative to a supplied ponding boundary.
- Saturated Unsaturated Conductivity Ratio Term
Return unsaturated/saturated conductivity ratio and reference gap.