# Hydrology & Open-Channel Calc – Orifice Discharge

> Hydrology & Open-Channel Calc – Orifice Discharge 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 orifice discharge flow rate Q = Cd × A × sqrt(2 × g × h) for round or custom-area openings, supporting multiple edge types and both SI and US units.

## Facts

- Endpoint: GET https://hydrology-calc.x402tookit.com/orifice-flow?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hydrology-open-channel-calc-orifice-discharge-2e9c2291
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_oBBq4AmXtya7mIyLWjEOC

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability hydrology-open-channel-calc-orifice-discharge-2e9c2291
```

Example prompt: Calculate the orifice discharge for a sharp-edged circular opening with a diameter of 0.15 m under a head of 2.5 m using SI units.

## When to prefer this

Use this endpoint when you need a quick, formula-based orifice discharge calculation (Q = Cd A sqrt(2gh)) with built-in typical Cd values by edge type, support for both SI and US units, and no need to set up local hydraulic software. Prefer it over general-purpose calculators when you specifically need orifice (submerged opening) flow rather than weir, pipe, or open-channel Manning flow.

## Known failure modes

- Missing required 'head' parameter returns an error
- Neither 'diameter' nor 'area' provided results in a calculation failure
- Cd override outside 0.3–1.0 range may be rejected or flagged
- Invalid 'edge' string not matching known enum values falls back to default or returns error
- Inconsistent unit combinations (e.g. metric diameter with us units) may produce unexpected results

## How this service works

Orifice discharge Q = Cd A sqrt(2 g h) for a round or given-area opening, with typical Cd by edge type, SI or US.

## Output

Returns the computed discharge Q (in m³/s or ft³/s), the discharge coefficient Cd used, orifice area, ideal velocity, supplemental flow values in litres/second or gallons/minute, a plain-language summary, the edge type applied, and a disclaimer about real-world applicability.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "head"
     ],
     "properties": {
      "cd": {
       "type": "number",
       "description": "Discharge coefficient override, 0.3 to 1"
      },
      "area": {
       "type": "number",
       "description": "Orifice area in m2 or ft2 (send area or diameter)"
      },
      "edge": {
       "type": "string",
       "description": "sharp (Cd 0.61, default), short-tube (0.82), rounded (0.98) or borda (0.51); or send cd"
      },
      "head": {
       "type": "number",
       "description": "Head h from the water surface to the orifice centre in metres (si) or feet (us)"
      },
      "units": {
       "type": "string",
       "description": "si (default) or us"
      },
      "diameter": {
       "type": "number",
       "description": "Orifice diameter in metres or feet (send diameter or area)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "cd": {
       "type": [
        "null",
        "number"
       ]
      },
      "area": {
       "type": [
        "null",
        "number"
       ]
      },
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "edge": {
       "type": [
        "null",
        "string"
       ]
      },
      "flow": {
       "type": [
        "null",
        "number"
       ]
      },
      "head": {
       "type": [
        "null",
        "number"
       ]
      },
      "units": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
    
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hydrology-open-channel-calc-orifice-discharge-2e9c2291/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hydrology-calc.x402tookit.com](https://www.zero.xyz/host/hydrology-calc.x402tookit.com/llms.txt)