Salt Wedge Intrusion Length
Fit an exponential salt-intrusion profile and locate a caller salinity crossing, explicitly flagging extrapolation; not a salt-wedge hydraulics solution or freshwater-use guarantee.
Description
An exponential salinity decline can summarize an observed upstream transect.
An exponential salinity decline can summarize an observed upstream transect. A comparison crossing may lie beyond the observed extent.
Fit an exponential salt-intrusion profile and locate a caller salinity crossing, explicitly flagging extrapolation; not a salt-wedge hydraulics solution or freshwater-use guarantee.
When to use Salt Wedge Intrusion Length
Use this tool to fit an exponential salt-intrusion profile and locate a caller salinity crossing, explicitly flagging extrapolation; not a salt-wedge hydraulics solution or freshwater-use guarantee.
Gather the water, wave, current or profile observations and any supplied calibration constants. Confirm units and the stated coordinate and pressure conventions.
How to use Salt Wedge Intrusion Length and understand its results
- Gather the water, wave, current or profile observations and any supplied calibration constants. Confirm units and the stated coordinate and pressure conventions.
- Enter upstreamDistancesM, observedSalinities, comparisonSalinity using the field table and calculation rules, then run the tool.
- Read fittedEFoldingLengthM, modelIntrusionDistanceM, isBeyondObservation, fitRSquared. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| upstreamDistancesM | Upstream distances m | list of number | Required |
| observedSalinities | Observed salinities | list of number | Required |
| comparisonSalinity | Comparison salinity | number | Required |
Use increasing nonnegative upstream distances, positive salinities and positive target. Require a declining fitted slope and reject crossings before the first station. Return e-folding length, crossing, beyond-observation flag and R².1
Each sequence checked for increasing order must contain at least two strictly increasing values. The least-squares fit needs at least two aligned observations and a varying independent variable; a constant dependent variable has reported R² of 1.
crossing distance = (ln(target salinity) − intercept)/log-salinity slope Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| fittedEFoldingLengthM | Fitted e folding length m | number |
| modelIntrusionDistanceM | Model intrusion distance m | number |
| isBeyondObservation | Is beyond observation | boolean |
| fitRSquared | Fit r squared | number |
{
"input": {
"upstreamDistancesM": [
0,
10,
20
],
"observedSalinities": [
10,
3.6787944117144233,
1.3533528323661268
],
"comparisonSalinity": 1
},
"output": {
"fittedEFoldingLengthM": 10,
"modelIntrusionDistanceM": 23.025850929940457,
"isBeyondObservation": true,
"fitRSquared": 1
}
}Limitations and assumptions
Extrapolation is explicit; the fit is not a hydraulic salt-wedge solution or freshwater-use guarantee.
Numbers and computed results must be finite; overflow produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use Knudsen Relationship Flow Ratio: Solve steady two-layer Knudsen volume/salt balances including nonzero river salinity, excluding evaporation/storage; salinities must share the same conservative concentration basis. For a complementary task, use Estuary Stratification Numeration Classifier: Screen river buoyancy versus tidal stirring with an estuarine Richardson-number convention and caller regimes; depth cancels in this convention, not a universal mixing classifier.
References
-
Salt Wedge Intrusion Length — tool.io
Similar or alternative tools
- Knudsen Relationship Flow Ratio
Solve steady two-layer Knudsen volume/salt balances including nonzero river salinity, excluding evaporation/storage; salinities must share the same conservative concentration basis.
- Estuary Stratification Numeration Classifier
Screen river buoyancy versus tidal stirring with an estuarine Richardson-number convention and caller regimes; depth cancels in this convention, not a universal mixing classifier.