Description
Multiply length by (referenceArea/drainageArea)^concavity for increment and add chiDownstream.
Geomorphic process terms summarize a supplied flow, slope, area, or sediment relation. Such a term describes the selected model; it does not establish erosion rate, transport capacity, or the complete process from one number.
Multiply length by (referenceArea/drainageArea)^concavity for increment and add chiDownstream.
When to use this tool
Use Channel Chi Coordinate One Reach Term when you need one process-model term with explicit supplied parameters.
How to use the tool and how it works
- Enter chiDownstream, reachLength, referenceArea, drainageArea, concavity. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read increment, chiUpstream. Use the output convention below.
Require nonnegative reachLength and positive referenceArea and drainageArea. Multiply length by (referenceArea/drainageArea)^concavity for increment and add chiDownstream.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| chiDownstream | Chi Downstream | Required. Finite number. |
| reachLength | Reach Length | Required. Finite number; minimum 0. |
| referenceArea | Reference Area | Required. Finite number; strictly above 0. |
| drainageArea | Drainage Area | Required. Finite number; strictly above 0. |
| concavity | Concavity | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| increment | Reach length times (referenceArea/drainageArea)^concavity; same length unit as χ. | Required. Finite number. |
| chiUpstream | Chi Upstream | Required. Finite number. |
{
"input": {
"chiDownstream": 10,
"reachLength": 100,
"referenceArea": 1,
"drainageArea": 4,
"concavity": 0.5
},
"output": {
"increment": 50,
"chiUpstream": 60
}
}Limitations and assumptions
- Areas share units and increment retains the length unit; this assumes constant representative drainage area over one reach, without integrating a full channel, fitting concavity, or inferring uplift.
- 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 the complete process model and site observations for interpretation. Review units, reach averaging, model calibration, and uncertainty rather than treating a local proxy as an observed process rate.
References
Similar or alternative tools
- Stream Power Unit Width Term
Return density × gravity × discharge × slope and divide by width.
- Relief Ratio Basin Length Term
Return relief and relief/basinLength.