Open-channel flow (Manning) API

Solves Manning's equation Q = (1/n)·A·R^(2/3)·S^(1/2) for a rectangular or trapezoidal channel, computing flow area, wetted perimeter, hydraulic radius, top width, velocity, and discharge. Answers 'What is the discharge in an open channel?', 'What flow velocity does Manning's equation give?'.

Price$0.06per request

MethodPOST

Route/v1/engineering/manning-flow

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

engineeringthermofluidsfluidsmanningopen-channeldischargehydraulic-radiushydrologydrainage

API URLhttps://x402.hexl.dev/v1/engineering/manning-flow

Integration docs

Example request

{
  "shape": "rectangular",
  "widthM": 3,
  "depthM": 1.2,
  "manningN": 0.013,
  "bedSlope": 0.001
}

Example response

{
  "shape": "rectangular",
  "flowAreaM2": 3.6,
  "wettedPerimeterM": 5.4,
  "hydraulicRadiusM": 0.666667,
  "topWidthM": 3,
  "velocityMs": 1.856361,
  "dischargeM3s": 6.6829,
  "dischargeLs": 6682.9002,
  "formula": "Q = (1/n)*A*R^(2/3)*S^(1/2), R = A/P  (SI Manning)"
}

Input schema

{
  "type": "object",
  "required": [
    "widthM",
    "depthM",
    "manningN",
    "bedSlope"
  ],
  "properties": {
    "shape": {
      "type": "string",
      "enum": [
        "rectangular",
        "trapezoidal"
      ],
      "examples": [
        "rectangular"
      ]
    },
    "widthM": {
      "type": "number",
      "description": "bottom width b (m)"
    },
    "depthM": {
      "type": "number",
      "description": "flow depth y (m)"
    },
    "sideSlope": {
      "type": "number",
      "description": "side slope z (H:V), trapezoidal only"
    },
    "manningN": {
      "type": "number",
      "description": "Manning roughness n",
      "examples": [
        0.013
      ]
    },
    "bedSlope": {
      "type": "number",
      "description": "channel bed slope S (m/m)",
      "examples": [
        0.001
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}