Overwash Freeboard Threshold Checker
Actual crest/water datum freeboard minus independent runup, negative exceedance retained; not overtopping discharge/hazard action. Caller independently establishes units, regime, calibration and applicability; this does not establish design-code compliance, authenticity, operational safety, treatment efficacy or a validated forecast.
Description
Freeboard measures the height of a crest above the still-water level.
Freeboard measures the height of a crest above the still-water level.1
Subtracting independently established runup gives a signed margin for a simple threshold review.
When to use Overwash Freeboard Threshold Checker
Use this tool to calculate or review the supplied observations under the stated rules. Match the observation interval, units, datum, coordinate signs and model regime.
How to use Overwash Freeboard Threshold Checker and understand its results
- Match the observation interval, units, datum, coordinate signs and model regime.
- Enter observedCrestElevationsM, matchedStillWaterElevationsM, callerIndependentlyEstablishedRunupM, using the field meanings and rules below, then run the tool.
- Read signedRunupFreeboardMarginsM, strictOverwashScreenIndices. Inspect nested result fields where present, and review unknown records separately from known matches.
- Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| observedCrestElevationsM | Observed crest elevations m | list of number | Required |
| matchedStillWaterElevationsM | Matched still water elevations m | list of number | Required |
| callerIndependentlyEstablishedRunupM | Caller independently established runup m | list of number | Required |
Enter aligned finite crest and still-water levels sharing one datum, and nonnegative runup. Compute crest−water−runup and return strictly negative margin indices; zero remains on the boundary.
margin_i=crest_i−water_i−runup_i Use the matching field units and the exact boundary, ordering and reference rules above.
| Output field | Meaning | Value type |
|---|---|---|
| signedRunupFreeboardMarginsM | Signed runup freeboard margins m; preserve the subtraction order and sign defined in the mechanics | list of number |
| strictOverwashScreenIndices | Strict overwash screen indices; zero-based positions in the relevant supplied record or adjacent-pair list | list of number |
{
"input": {
"observedCrestElevationsM": [
3,
4
],
"matchedStillWaterElevationsM": [
2,
2
],
"callerIndependentlyEstablishedRunupM": [
2,
1
]
},
"output": {
"signedRunupFreeboardMarginsM": [
-1,
1
],
"strictOverwashScreenIndices": [
0
]
}
}Limitations and assumptions
The stated observation or model covers only the supplied record and reference regime. It does not fill missing measurements, supply uncertainty estimates or produce a validated forecast.
Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite. Lists and matrices must be dense, without missing cells. Numeric lists allow at most 10000 entries; ordinary string lists allow at most 128 strings of 128 UTF-16 units each; numeric matrices allow at most 128 rows and 128 columns, subject to narrower requirements above.
Alternative or Complementary methods
For a related step, use Setup Plus Swash Stockdon Split Calculator: Wave setup and swash contribute to extreme runup on a beach. For a complementary comparison, use Storm Surge Hydrostatic Contribution Calculator: Atmospheric pressure changes contribute to sea-level anomalies through the inverse-barometer balance.
References
-
Overwash Freeboard Threshold Checker — tool.io
Similar or alternative tools
- Setup Plus Swash Stockdon Split Calculator
Wave setup and swash contribute to extreme runup on a beach.
- Storm Surge Hydrostatic Contribution Calculator
Atmospheric pressure changes contribute to sea-level anomalies through the inverse-barometer balance.