Water Quality Mixing Conservative One Inflow Tool

Description

Return total flow and concentration = (baseFlow*baseConcentration + inflow*inflowConcentration)/(baseFlow+inflow).

A mixture concentration follows the amount of substance carried by each component, not an unweighted average of concentrations. Flow-weighted and volume-weighted balances require compatible units and assumptions about mixing, losses and treatment.

Return total flow and concentration = (baseFlow*baseConcentration + inflow*inflowConcentration)/(baseFlow+inflow).

When to use this tool

Use Water Quality Mixing Conservative One Inflow when checking a conservative mixture or a supplied proportional-removal term.

How to use the tool and how it works

Enter baseFlow, baseConcentration, inflow, inflowConcentration. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read flow, concentration. Use the output convention below.

Require nonnegative baseFlow and inflow with a positive sum. Return total flow and concentration = (baseFlow*baseConcentration + inflow*inflowConcentration)/(baseFlow+inflow). Flows must share one volume/time basis and concentrations one mass/volume basis.^[1]

Input field	Meaning and units	Accepted input
baseFlow	Base Flow	Required. Finite number; minimum 0.
baseConcentration	Base Concentration	Required. Finite number.
inflow	Inflow	Required. Finite number; minimum 0.
inflowConcentration	Inflow Concentration	Required. Finite number.

Output field	Interpretation	Returned shape
flow	Volume per time, on the concentration and duration unit basis used in the formula.	Required. Finite number.
concentration	Amount per volume, in a unit compatible with the supplied flow or volume.	Required. Finite number.

json

{
  "input": {
    "baseFlow": 8,
    "baseConcentration": 2,
    "inflow": 2,
    "inflowConcentration": 7
  },
  "output": {
    "flow": 10,
    "concentration": 3
  }
}

Limitations and assumptions

This assumes complete conservative mixing with no loss, reaction or storage. Concentrations are finite signed numbers under the contract; negative values are accepted arithmetic inputs, not proof of physically negative solute mass or safe water.
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 a dynamic mass-balance or reaction model when storage, incomplete mixing, changing inputs or chemical transformations matter.

References

Calculation and input contract: environmental-science/water-quality-mixing-conservative-one-inflow — tool.io

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