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Hydrology & Open-Channel Calc – Rational Method Peak Runoff
x402
Hydrology & Open-Channel Calc – Rational Method Peak Runoff 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 peak stormwater runoff flow Q = C × i × A using the rational method, supporting direct runoff coefficient, surface type lookup, or weighted sub-areas in SI or US units.
Price / call$0.02
Success—
StatusUnknown
How this service works
Peak runoff Q = C i A by the rational method, from a runoff coefficient, surface type or weighted sub-areas, SI or US.
Output
Returns the calculated peak runoff flow Q (in m³/s or ft³/s depending on unit system), the effective runoff coefficient used, rainfall intensity, catchment area, flow in liters per second, unit labels, a human-readable summary, coefficient range for the selected surface type, and a disclaimer about the rational method's applicability limits.
Example use cases
Parking lot stormwater drainage design
“I'm designing drainage for a 2-acre asphalt parking lot. Can you calculate the peak runoff using the rational method with a rainfall intensity of 3.5 in/h in US units?”
Mixed land-use watershed peak flow
“I have a watershed with two sub-areas: 0.9 runoff coefficient over 2 hectares and 0.3 over 8 hectares. The design rainfall intensity is 60 mm/h. What's the peak discharge using the rational method in SI units?”
Residential roof drain sizing
“What's the peak runoff flow from a 0.5-hectare residential roof with a 100 mm/h design storm? Use SI units and the roof surface type for the runoff coefficient.”
Technical details
Endpoint
GEThttps://hydrology-calc.x402tookit.com/rational-method?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a fast, standards-based rational method peak runoff calculation for small catchments (typically <80 ha or 200 acres), especially when working with mixed land-use sub-areas or need surface-type lookup for C values. Prefer it over manual calculation or spreadsheets for automated pipelines, and when both SI and US unit support is needed in a single API.
Side effects
- Missing required parameters (rainfallIntensity or area) returns an error
- Conflicting inputs (c, surface, and subareas all provided) may cause ambiguous results
- Runoff coefficient outside 0–1 range is rejected
- Unknown surface type string returns an error or falls back
- Very large or zero area values may produce unrealistic results without explicit warnings
- Unit system mismatch (e.g., acres with SI intensity) produces incorrect output if not specified carefully
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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