{
 "tool": "culvert",
 "toolVersion": "1.1.0",
 "methods": [
  "culvert 1.1.0"
 ],
 "commit": "ab22876",
 "date": "2026-11-04",
 "summary": "14 of 14 cases (536 values) within tolerance against HY-8 8.0.1.2.",
 "note": "Generated by _workspace/tools/hh_verification.mjs from the fixtures; commit = code verified.",
 "cases": [
  {
   "id": "HY-1",
   "what": "48-in pipe, conc-groove-headwall, 11 flows 20–200 cfs (inlet control)",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-01)",
   "compared": 38,
   "maxDiff": "1.51 %",
   "pass": true
  },
  {
   "id": "HY-2",
   "what": "48-in pipe, conc-groove-headwall, 11 flows 20–150 cfs (outlet control)",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-01)",
   "compared": 55,
   "maxDiff": "1.24 %",
   "pass": true
  },
  {
   "id": "HY-3",
   "what": "48-in pipe, conc-groove-headwall, 11 flows 20–150 cfs (outlet control)",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-01)",
   "compared": 55,
   "maxDiff": "1.24 %",
   "pass": true
  },
  {
   "id": "HY-4",
   "what": "6 × 4 ft box, box-wing-30-75, 11 flows 50–400 cfs (inlet control)",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-01)",
   "compared": 44,
   "maxDiff": "4.83 %",
   "pass": true
  },
  {
   "id": "HY-5",
   "what": "36-in pipe, cmp-projecting, 11 flows 10–80 cfs (inlet control)",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-01)",
   "compared": 29,
   "maxDiff": "4.53 %",
   "pass": true
  },
  {
   "id": "HY-6",
   "what": "48-in pipe, conc-groove-headwall, 11 flows 20–200 cfs (outlet and inlet control)",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-01)",
   "compared": 40,
   "maxDiff": "1.51 %",
   "pass": true
  },
  {
   "id": "HY-7",
   "what": "4-ft pipe, paved road 5 ft above the inlet invert, 100 ft crest, 11 flows, 20 to 200 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 33,
   "maxDiff": "1.51 %",
   "pass": true
  },
  {
   "id": "HY-8",
   "what": "Three 4-ft pipes, gravel road, 200 ft crest, 11 flows, 100 to 1000 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 33,
   "maxDiff": "1.28 %",
   "pass": true
  },
  {
   "id": "HY-9",
   "what": "Two box barrels, narrow paved crest (HW_r/L_r above 0.15), 11 flows, 100 to 2000 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 33,
   "maxDiff": "3.32 %",
   "pass": true
  },
  {
   "id": "HY-10",
   "what": "4-ft pipe, tailwater 1 ft above a paved crest (submerged road), 11 flows, 150 to 800 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 33,
   "maxDiff": "1.44 %",
   "pass": true
  },
  {
   "id": "HY-11",
   "what": "Two 4-ft pipes, tailwater from normal depth in a trapezoidal channel, gravel road, 11 flows, 50 to 800 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 44,
   "maxDiff": "1.36 %",
   "pass": true
  },
  {
   "id": "HY-12",
   "what": "4-ft pipe, entered road coefficient 2.8, 11 flows, 150 to 800 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 33,
   "maxDiff": "0.85 %",
   "pass": true
  },
  {
   "id": "HY-14",
   "what": "4-ft pipe, entered road coefficient 2.8, tailwater above the crest, 11 flows, 260 to 340 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 33,
   "maxDiff": "0.24 %",
   "pass": true
  },
  {
   "id": "HY-13",
   "what": "Four corrugated metal pipes, projecting, road not reached, 11 flows, 40 to 320 cfs",
   "reference": "HY-8 8.0.1.2 (owner-run 2026-11-04)",
   "compared": 33,
   "maxDiff": "4.53 %",
   "pass": true
  }
 ]
}