{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://www.calculatorx.com/schemas/physics.fluid.manning/1.0.0/input.json",
  "title": "Manning formula — input",
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "mode": {
      "type": "string",
      "enum": [
        "discharge",
        "velocity",
        "n",
        "slope"
      ],
      "description": "discharge (default) solves Q; velocity, n, and slope invert the same SI formula."
    },
    "n": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Manning roughness n. Required except mode=n."
    },
    "A": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Flow area in m². Required except velocity without P."
    },
    "R": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Hydraulic radius in m. Alternative: A and P. Do not send R and P together."
    },
    "P": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Wetted perimeter in m. Requires A. Do not send with R."
    },
    "S": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Friction slope (rise/run). Required except mode=slope."
    },
    "Q": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Discharge in m³/s. Required for mode=n and mode=slope."
    }
  },
  "description": "SI Manning open-channel discharge Q = (1/n) A R^{2/3} S^{1/2}. k=1. Not Q=Av, not Darcy–Weisbach, not a weir, not US customary 1.486. (calculation_version 1.0.0)"
}