Phosphorus Retention Coefficient
Close matched phosphorus inflow/outflow/storage budget to apparent retention; negative retention or ratios above one expose unmodeled exchange and are not clamped.
Description
A phosphorus budget reconciles inflow, outflow and change in the water-column inventory.
A phosphorus budget reconciles inflow, outflow and change in the water-column inventory. The residual describes apparent retention after correcting for storage.1
The tool returns apparentSedimentRetentionKg, storageCorrectedRetentionFraction. The computation uses supplied observations and parameters rather than acquiring measurements.
When to use Phosphorus Retention Coefficient
Use this for the following task: Close matched phosphorus inflow/outflow/storage budget to apparent retention; negative retention or ratios above one expose unmodeled exchange and are not clamped. Prepare observations and calibration parameters on the same unit and reporting basis.
How to use Phosphorus Retention Coefficient and understand its results
- Prepare the measured quantities and supplied model parameters. Match the units and align paired lists before calculating.
- Enter incomingPhosphorusKg, outgoingPhosphorusKg, waterColumnStorageChangeKg according to the field table, then run the tool.
- Read apparentSedimentRetentionKg, storageCorrectedRetentionFraction. Use the calculation below to interpret the selected mean or the model’s signs, units and comparison flags.
- Review the supplied assumptions and calibration before comparing or reporting the result.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| incomingPhosphorusKg | Incoming phosphorus kg | number | Required |
| outgoingPhosphorusKg | Outgoing phosphorus kg | number | Required |
| waterColumnStorageChangeKg | Water column storage change kg | number | Required |
Use positive incoming mass, nonnegative outgoing mass and a signed storage change for the same interval. Return retained mass and its ratio to incoming phosphorus.
retention kg=incoming−outgoing−storageChange; fraction=retention/incoming The symbols and boundary conditions refer to the supplied fields and the implementation described above.
| Output field | Meaning | Value type |
|---|---|---|
| apparentSedimentRetentionKg | Apparent sediment retention kg | number |
| storageCorrectedRetentionFraction | Storage corrected retention fraction | number |
{
"input": {
"incomingPhosphorusKg": 100,
"outgoingPhosphorusKg": 40,
"waterColumnStorageChangeKg": 10
},
"output": {
"apparentSedimentRetentionKg": 50,
"storageCorrectedRetentionFraction": 0.5
}
}Limitations and assumptions
Negative retention and fractions above one are retained rather than clamped. Missing exchanges or incompatible periods can affect the residual; sediment capture is not directly measured.
Numerical inputs must be finite. Input-shape and calculation checks do not establish measurement quality or the validity of a supplied calibration.
Alternative or Complementary methods
Choose Internal Load Release Areal Rate when you need its operation: Infer signed internal phosphorus release as the residual of observed water inventory and external exchange, normalized by active sediment area/time; other missing processes can contribute to the residual. Choose Chloride Conservative Mass Balance Checker for the complementary operation: Audit conservative dissolved chloride inventory with trapezoidal sampled mass-flux integration and independent final inventory; this tracer is not chlorine disinfectant, and groundwater/deposition inputs must be included externally.
Background reference: Water Quality, Hydrology, and Response to Changes in Phosphorus Loading of Nagawicka Lake.
References
-
Water Quality, Hydrology, and Response to Changes in Phosphorus Loading of Nagawicka Lake — U.S. Geological Survey
Similar or alternative tools
- Internal Load Release Areal Rate
Infer signed internal phosphorus release as the residual of observed water inventory and external exchange, normalized by active sediment area/time; other missing processes can contribute to the residual.
- Chloride Conservative Mass Balance Checker
Audit conservative dissolved chloride inventory with trapezoidal sampled mass-flux integration and independent final inventory; this tracer is not chlorine disinfectant, and groundwater/deposition inputs must be included externally.