Description
Return firstMass, volumeShare = firstVolume/totalVolume, massShare = firstMass/totalMass and enrichment = firstConcentration/(totalMass/totalVolume).
A pollutant load combines concentration with a compatible flow, volume or activity factor. A load rate has amount-per-time units, whereas an integrated load also includes duration; concentration differences alone do not describe removal when flows differ.
Return firstMass, volumeShare = firstVolume/totalVolume, massShare = firstMass/totalMass and enrichment = firstConcentration/(totalMass/totalVolume).
When to use this tool
Use Stormwater First Flush Mass Share Term when checking one supplied emission, transport or treatment mass-balance contribution.
How to use the tool and how it works
- Enter firstVolume, firstConcentration, totalVolume, totalMass. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read firstMass, volumeShare, massShare, enrichment. Use the output convention below.
Require positive totalVolume and totalMass, 0 <= firstVolume <= totalVolume, nonnegative firstConcentration and firstVolume*firstConcentration <= totalMass. Return firstMass, volumeShare = firstVolume/totalVolume, massShare = firstMass/totalMass and enrichment = firstConcentration/(totalMass/totalVolume).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| firstVolume | First Volume | Required. Finite number; minimum 0. |
| firstConcentration | First Concentration | Required. Finite number; minimum 0. |
| totalVolume | Total Volume | Required. Finite number; strictly above 0. |
| totalMass | Total Mass | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| firstMass | First Mass | Required. Finite number. |
| volumeShare | Volume Share | Required. Finite number. |
| massShare | Mass Share | Required. Finite number. |
| enrichment | First concentration divided by the total mean concentration, independent of firstVolume. | Required. Finite number. |
{
"input": {
"firstVolume": 10,
"firstConcentration": 3,
"totalVolume": 100,
"totalMass": 100
},
"output": {
"firstMass": 30,
"volumeShare": 0.1,
"massShare": 0.3,
"enrichment": 3
}
}Limitations and assumptions
- Concentration and volume must multiply to the totalMass unit. enrichment compares concentrations and can remain nonzero when firstVolume is zero; no actual first-flush segment or pollutant capture design is selected.
- 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
Integrate changing measurements over time and reconcile storage and reactions when a constant-condition product is insufficient.
References
Similar or alternative tools
- Pollutant Load Concentration Flow Term
Return load = concentration*flow*duration*unitFactor.
- Water Reuse Blending Concentration Term Tool
Calculate conservative two-volume water blending concentration with additive volumes and compatible mass-concentration units.