{
 "tool": "detention-routing",
 "toolVersion": "1.0.0",
 "methods": [
  "routing 1.0.0",
  "uh 1.0.0",
  "storage 1.0.0"
 ],
 "commit": "ab22876",
 "date": "2026-11-04",
 "summary": "32 of 32 cases (79 values) within tolerance against HEC-HMS 4.13, FHWA HEC-22 4th ed., Hand calculation of the published equation.",
 "note": "Generated by _workspace/tools/hh_verification.mjs from the fixtures; commit = code verified.",
 "cases": [
  {
   "id": "HMS-1",
   "what": "Triangular inflow, 100 cfs peak; one 24-in orifice",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 4,
   "maxDiff": "0.40 %",
   "pass": true
  },
  {
   "id": "HMS-2",
   "what": "Same pond, 250 cfs peak; 24-in orifice and a 20-ft broad-crested spillway that overflows",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 5,
   "maxDiff": "0.06 %",
   "pass": true
  },
  {
   "id": "HMS-3",
   "what": "Two orifices at different elevations and a spillway, a long inflow of 150 cfs over 6 hours",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 5,
   "maxDiff": "0.72 %",
   "pass": true
  },
  {
   "id": "HMS-4",
   "what": "Pond starting partly full (elevation 102) with the same inflow as case 1",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 5,
   "maxDiff": "0.01 %",
   "pass": true
  },
  {
   "id": "HMS-5",
   "what": "Short peaked inflow routed at a 1-minute step: 300 cfs over 40 minutes, spillway overflow",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 4,
   "maxDiff": "0.92 %",
   "pass": true
  },
  {
   "id": "HMS-6",
   "what": "Large pond: 600 cfs over 12 hours through a 48-in orifice and a 60-ft spillway",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 4,
   "maxDiff": "1.23 %",
   "pass": true
  },
  {
   "id": "HMS-7",
   "what": "Orifice under a constant tailwater at elevation 103: the outlet runs submerged at the peak",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 5,
   "maxDiff": "0.02 %",
   "pass": true
  },
  {
   "id": "HMS-8",
   "what": "Elevation-area table (conic storage): 120 cfs through a 30-in orifice",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 4,
   "maxDiff": "1.69 %",
   "pass": true
  },
  {
   "id": "HMS-9",
   "what": "A 36-in concrete pipe with a groove end in a headwall as the only outlet (HDS-5 inlet and outlet control)",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 5,
   "maxDiff": "6.25 %",
   "pass": true
  },
  {
   "id": "HMS-UH-1",
   "what": "40 ac, CN 88, lag 12 min, Type III, 7.5 in, 6-min step",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 3,
   "maxDiff": "0.01 %",
   "pass": true
  },
  {
   "id": "HMS-UH-2",
   "what": "250 ac, CN 75, lag 54 min, Type II, 6 in, 6-min step",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 3,
   "maxDiff": "0.29 %",
   "pass": true
  },
  {
   "id": "HMS-UH-3",
   "what": "1,000 ac, CN 70, lag 120 min, Type III, 11 in, 15-min step",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 3,
   "maxDiff": "0.37 %",
   "pass": true
  },
  {
   "id": "HMS-UH-4",
   "what": "10 ac, CN 98, lag 6 min, Type II, 3 in, 5-min step",
   "reference": "HEC-HMS 4.13 (owner-run 2026-11-04)",
   "compared": 3,
   "maxDiff": "2.79 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.10-33.5",
   "what": "Orifice rating, 0.49-ft circular orifice at stage 33.5 ft",
   "reference": "FHWA HEC-22 4th ed. Example 10.10, table 10.6",
   "compared": 1,
   "maxDiff": "0.36 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.10-34.8",
   "what": "Orifice rating, 0.49-ft circular orifice at stage 34.8 ft",
   "reference": "FHWA HEC-22 4th ed. Example 10.10, table 10.6",
   "compared": 1,
   "maxDiff": "0.20 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.10-36.1",
   "what": "Orifice rating, 0.49-ft circular orifice at stage 36.1 ft",
   "reference": "FHWA HEC-22 4th ed. Example 10.10, table 10.6",
   "compared": 1,
   "maxDiff": "0.23 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.10-37.4",
   "what": "Orifice rating, 0.49-ft circular orifice at stage 37.4 ft",
   "reference": "FHWA HEC-22 4th ed. Example 10.10, table 10.6",
   "compared": 1,
   "maxDiff": "0.22 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.10-38.7",
   "what": "Orifice rating, 0.49-ft circular orifice at stage 38.7 ft",
   "reference": "FHWA HEC-22 4th ed. Example 10.10, table 10.6",
   "compared": 1,
   "maxDiff": "0.08 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.10-39.4",
   "what": "Orifice rating, 0.49-ft circular orifice at stage 39.4 ft",
   "reference": "FHWA HEC-22 4th ed. Example 10.10, table 10.6",
   "compared": 1,
   "maxDiff": "0.09 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.11-0.33",
   "what": "Riser rating at 0.33 ft of head: the smaller of weir and orifice flow",
   "reference": "FHWA HEC-22 4th ed. Example 10.11, table 10.8",
   "compared": 1,
   "maxDiff": "1.99 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.11-0.66",
   "what": "Riser rating at 0.66 ft of head: the smaller of weir and orifice flow",
   "reference": "FHWA HEC-22 4th ed. Example 10.11, table 10.8",
   "compared": 1,
   "maxDiff": "1.06 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.11-1.31",
   "what": "Riser rating at 1.31 ft of head: the smaller of weir and orifice flow",
   "reference": "FHWA HEC-22 4th ed. Example 10.11, table 10.8",
   "compared": 1,
   "maxDiff": "0.01 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.11-1.97",
   "what": "Riser rating at 1.97 ft of head: the smaller of weir and orifice flow",
   "reference": "FHWA HEC-22 4th ed. Example 10.11, table 10.8",
   "compared": 1,
   "maxDiff": "1.03 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.11-2.63",
   "what": "Riser rating at 2.63 ft of head: the smaller of weir and orifice flow",
   "reference": "FHWA HEC-22 4th ed. Example 10.11, table 10.8",
   "compared": 1,
   "maxDiff": "0.75 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.11-3.28",
   "what": "Riser rating at 3.28 ft of head: the smaller of weir and orifice flow",
   "reference": "FHWA HEC-22 4th ed. Example 10.11, table 10.8",
   "compared": 1,
   "maxDiff": "0.35 %",
   "pass": true
  },
  {
   "id": "HEC22-E10.11-3.94",
   "what": "Riser rating at 3.94 ft of head: the smaller of weir and orifice flow",
   "reference": "FHWA HEC-22 4th ed. Example 10.11, table 10.8",
   "compared": 1,
   "maxDiff": "0.52 %",
   "pass": true
  },
  {
   "id": "HEC22-T10.11",
   "what": "Stage-storage by average area, HEC-22 table 10.11",
   "reference": "FHWA HEC-22 4th ed. Example 10.14, table 10.11",
   "compared": 8,
   "maxDiff": "0.00 %",
   "pass": true
  },
  {
   "id": "ARITH-CONIC",
   "what": "Conic section on a square pond with 3:1 sides, 4 ft deep: the frustum volume",
   "reference": "Hand calculation of the published equation (published example)",
   "compared": 1,
   "maxDiff": "0.00 %",
   "pass": true
  },
  {
   "id": "ARITH-LINEAR",
   "what": "Linear reservoir, S = K O with K 2 hours, steady 50 cfs for 4 hours: O = I (1 - e^(-t/K))",
   "reference": "Hand calculation of the published equation (published example)",
   "compared": 1,
   "maxDiff": "0.00 %",
   "pass": true
  },
  {
   "id": "ARITH-DRAIN",
   "what": "A 1-ft orifice draining a 2-ac vertical-sided pond from 10 ft: time to 10% of the storage (Torricelli)",
   "reference": "Hand calculation of the published equation (published example)",
   "compared": 1,
   "maxDiff": "0.02 %",
   "pass": true
  },
  {
   "id": "ARITH-TOP",
   "what": "Inflow that rises above the top of the table (refusal, not extended)",
   "reference": "Hand calculation of the published equation (published example)",
   "compared": 1,
   "maxDiff": "both refuse",
   "pass": true
  },
  {
   "id": "ARITH-SUBSPILL",
   "what": "Broad-crested spillway under a tailwater above its crest (refusal)",
   "reference": "Hand calculation of the published equation (published example)",
   "compared": 1,
   "maxDiff": "both refuse",
   "pass": true
  }
 ]
}