Snyder Unit Hydrograph Calculator
Snyder empirical lag HOURS with caller calibrated km-based Ct and unit peak 2.78CpA/tlag PER CM excess, not PER MM or full shaped hydrograph. 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
Snyder-style hydrograph relations use basin dimensions and calibrated coefficients.
Snyder-style hydrograph relations use basin dimensions and calibrated coefficients.1
The peak is expressed per centimeter of runoff depth under this implementation's unit convention. Use this tool to calculate snyder Unit Hydrograph from the supplied measurements and assumptions.
When to use Snyder Unit Hydrograph Calculator
Use this tool to calculate snyder Unit Hydrograph from the supplied measurements and assumptions. Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
How to use Snyder Unit Hydrograph Calculator and understand its results
- Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
- Enter mainStreamLengthKm, centroidStreamLengthKm, callerSnyderLagCoefficient, callerSnyderPeakingCoefficient, catchmentAreaKm2, using the field meanings and rules below, then run the tool.
- Read snyderLagHours, snyderUnitPeakM3SecondPerCm. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| mainStreamLengthKm | Main stream length km | number | Required |
| centroidStreamLengthKm | Centroid stream length km | number | Required |
| callerSnyderLagCoefficient | Caller snyder lag coefficient | number | Required |
| callerSnyderPeakingCoefficient | Caller snyder peaking coefficient | number | Required |
| catchmentAreaKm2 | Catchment area km2 | number | Required |
Enter positive basin length and centroid length in km, area in km² and independently calibrated Snyder Ct/Cp coefficients. Lag is Ct×(L×Lc)^0.3 hours; peak is 2.78×Cp×area/lag. The peak is per centimeter of runoff depth under the committed formula, not the per-mm basis of the separate unit-hydrograph tool.
lagHours=Ct×(Lkm×Lckm)^0.3; peakM³/sPerCm=2.78×Cp×areaKm²/lagHours Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| snyderLagHours | Snyder Lag Hours; follow the units, sign, ordering and evidence convention stated above | number |
| snyderUnitPeakM3SecondPerCm | Snyder Unit Peak M3 Second Per Cm; follow the units, sign, ordering and evidence convention stated above | number |
{
"input": {
"mainStreamLengthKm": 10,
"centroidStreamLengthKm": 5,
"callerSnyderLagCoefficient": 1,
"callerSnyderPeakingCoefficient": 0.5,
"catchmentAreaKm2": 2
},
"output": {
"snyderLagHours": 3.233635032886787,
"snyderUnitPeakM3SecondPerCm": 0.8597135952965569
}
}Limitations and assumptions
The peak is expressed per centimeter of runoff depth under this implementation's unit convention. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Unit Hydrograph Peak Calculator for this related task: A unit hydrograph describes discharge response on an explicitly stated rainfall-depth basis.
Use Muskingum Flood Routing Calculator when its separate inputs and assumptions fit the question: Muskingum routing uses a storage-time parameter and weighting to advance an outflow sequence.
References
-
Snyder Unit Hydrograph Calculator — tool.io
Similar or alternative tools
- Unit Hydrograph Peak Calculator
A unit hydrograph describes discharge response on an explicitly stated rainfall-depth basis.
- Muskingum Flood Routing Calculator
Muskingum routing uses a storage-time parameter and weighting to advance an outflow sequence.