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Hydrology & Open-Channel Calc — Weir Flow
x402
Hydrology & Open-Channel Calc — Weir Flow is a paid API for AI agents from hydrology-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-02).
Calculates discharge (flow rate) over a sharp-crested rectangular (Francis), V-notch, or Cipolletti weir from head measurement, in SI or US customary units.
Price / call$0.02
Success—
StatusUnknown
How this service works
Discharge over a sharp-crested rectangular (Francis), V-notch or Cipolletti weir from head, SI or US units.
Output
Returns the computed flow rate (Q) in m³/s or ft³/s, along with the weir type, head, flow unit, effective discharge coefficient, crest length, notch angle, contraction count, a plain-language summary, and any applicable warnings or disclaimers.
Example use cases
Irrigation canal flow measurement
“I need to know how much water is flowing over a Cipolletti weir with a 1.2-metre crest length and a measured head of 0.25 metres — give me the answer in SI units (m³/s).”
Field gauging with Francis correction
“What's the discharge over a rectangular weir that's 2.5 feet wide, head of 0.8 feet, with 2 end contractions, using US customary units? Use the standard Francis formula.”
Custom V-notch angle flow estimate
“Calculate the flow through a 60-degree V-notch weir with a head of 0.18 metres in SI units — use the default discharge coefficient.”
Technical details
Endpoint
GEThttps://hydrology-calc.x402tookit.com/weir-flow?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a fast, authoritative hydraulic calculation for standard sharp-crested weir types (rectangular/Francis, V-notch, Cipolletti) given a known upstream head, and you want SI or US unit output with optional custom discharge coefficients or Francis end-contraction corrections. Prefer this over general engineering calculators when you need weir-specific formulas with proper physical constraints and structured JSON output.
Side effects
- Missing required 'type' or 'head' parameters returns an error
- Head value of zero or negative causes invalid computation
- crestLength omitted for rectangular or Cipolletti weir returns error or null flow
- notchAngleDeg outside 10–120 degree range may trigger a warning or rejection
- Invalid weir type string returns an unrecognised-type error
- Extremely large head values may produce physically unrealistic results with a warning
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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