Description
Compute trapezoid area, bottom plus two sloping-side lengths as wettedPerimeter, and area/perimeter as hydraulicRadius.
Ideal water-storage and channel geometry uses dimensions, areas, and displacement fractions. Coherent length units determine areas and volumes; actual irregular geometry and hydraulic behavior require additional information.
Compute trapezoid area, bottom plus two sloping-side lengths as wettedPerimeter, and area/perimeter as hydraulicRadius.
When to use this tool
Use Stream Section Trapezoid Wetted Perimeter when you need one explicit geometric component of a tank, bed, conduit, or channel.
How to use the tool and how it works
- Enter bottomWidth, depth, sideSlope. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read area, wettedPerimeter, hydraulicRadius. Use the output convention below.
Require nonnegative bottomWidth and sideSlope, positive depth, and nondegenerate width/slope. Compute trapezoid area, bottom plus two sloping-side lengths as wettedPerimeter, and area/perimeter as hydraulicRadius.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| bottomWidth | Bottom Width | Required. Finite number; minimum 0. |
| depth | Depth on the length basis stated above. | Required. Finite number; strictly above 0. |
| sideSlope | Nonnegative horizontal run per unit vertical rise on each bank, not an angle. | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| area | Area on the common unit basis stated above. | Required. Finite number. |
| wettedPerimeter | Wetted Perimeter | Required. Finite number. |
| hydraulicRadius | Wetted area divided by wetted perimeter, in the input length unit. | Required. Finite number. |
{
"input": {
"bottomWidth": 4,
"depth": 2,
"sideSlope": 0
},
"output": {
"area": 8,
"wettedPerimeter": 8,
"hydraulicRadius": 1
}
}Limitations and assumptions
- SideSlope is horizontal run per vertical rise on each side; dimensions share a length unit. Free surface is excluded from wetted perimeter, and no discharge, roughness, or channel safety is evaluated.
- 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
Check the full surveyed geometry and the physical model before interpreting storage, capacity, or safe operation.
References
Similar or alternative tools
- Open Channel Wetted Perimeter Panel Term
Use the hypotenuse of horizontalWidth and the depth difference as bedLength.
- Circular Conduit Part Full Angle Factor
Return radius squared times (angle-sine(angle))/2 for area and radius times angle for wettedPerimeter.