Description
Require retentionPerDay strictly between zero and one and return ln(0.5)/ln(retentionPerDay) as halfLifeDays.
Groundwater components relate hydraulic head, storage, porosity, and supplied flow parameters. A local equation uses a declared aquifer model; it does not establish that model from field observations.
Require retentionPerDay strictly between zero and one and return ln(0.5)/ln(retentionPerDay) as halfLifeDays.
When to use this tool
Use Baseflow Recession Half Life Factor when you need one explicit groundwater or soil-storage component.
How to use the tool and how it works
- Enter retentionPerDay. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read halfLifeDays. Use the output convention below.
Require retentionPerDay strictly between zero and one and return ln(0.5)/ln(retentionPerDay) as halfLifeDays.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| retentionPerDay | Strictly positive daily remaining-flow multiplier below one; not the fraction lost. | Required. Finite number; strictly above 0; strictly below 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| halfLifeDays | Time in days to halve flow under the constant supplied recession factor. | Required. Finite number. |
{
"input": {
"retentionPerDay": 0.5
},
"output": {
"halfLifeDays": 1
}
}Limitations and assumptions
- Retention is the multiplicative one-day remaining-flow factor, not the fraction lost per day; this assumes constant exponential recession without estimating it from observations.
- 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 suitable field measurements, aquifer assumptions, and a complete groundwater analysis for resource or safety decisions.
References
Similar or alternative tools
- Base Flow Time Point Fraction
Return baseflow/total, total-baseflow, and physicalBalance for baseflow no greater than total.
- Seepage Velocity Porosity Factor
Divide signed darcyFlux by effectivePorosity in (0, 1] for seepageVelocity.