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    "Default C_d=0.62; optional C_d in (0, 1]",
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    "Not free-flow thin-plate H only, not ogee Hd, not side weir B+Q1, not Manning n, not Q=Av, not V-notch"
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    "H2/H1 < 0.20, free-flow H, Hd, B/Q1, n, A/v, b, θ → MIXED_INPUT_ENCODING",
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      "title": "ISO 1438 — Hydrometry — Open channel flow measurement using thin-plate weirs",
      "section": "Rectangular thin-plate weirs",
      "url": "https://www.iso.org/standard/41711.html",
      "supports": "Free-flow Qf from head over a sharp crest; this page multiplies Qf by Villemonte",
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    {
      "title": "Villemonte, J.R. Submerged-weir discharge studies",
      "section": "Engineering News-Record 139(26), 1947",
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    {
      "title": "ISO 80000-4 — Mechanics",
      "section": "Volume flow rate",
      "url": "https://www.iso.org/standard/31895.html",
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