2022-08-25_PERMIT FILE - C1981012 ‎(20)‎

• Permit No: C1981012
• IBM Index Class Name: Permit File
• Doc Date: 8/25/2022
• Section_Exhibit Name: Section 2.05 Operation and Reclamation Plan
• Media Type: D
• Archive: No

17a
Section 2.05 TR-76 7/25/2022
Table 19a TR-76 Haul Road Culverts
Culvert ID Watershed
ID
Drainage
Area
(acres)
Curve
Number
10-year, 24-
hour peak
flow (CFS)
Culvert
Size (in)
Culvert Max
Discharge
(CFS)
Culvert 1A, 1A1 1 45.84 85 94.5 60 121.6
Culvert 2A, 2B2 2 54 85 111.3 60 275.1
Culvert 3 3 12.55 85 27.0 48 103.2
Culvert 4 4 20.12 85 41.5 12 6.2
Culvert 5 5 50.85 85 108.6 48 56.1
Culvert 6 6 15.62 85 33.6 42 58.2
Culvert 7A, 7B2 7 27.02 85 57.7 36 61.1
Culvert 8A, 8B2 8 11.12 85 23.8 14 25.7
Culvert 9A, 9B2 9 19.4 85 41.4 14 5.3
Culvert 10 10 9.81 85 21.1 14 4.8
Culvert 11A, 11B1 11 18.81 85 40.2 14 4.8
Culvert 12A, 12B, 12C3 12 10.49 85 22.5 18 14.5
Culvert 134 13 5.54 86 12.5
Culvert 14 14 3.71 86 8.4 18 4.8
Total 13-14 20.9 4.8
Culvert 15 15 3.54 86 8.0 18 4.8
Culvert 16 16 3.54 86 8.0 26 15.8
Culvert 174 17 2.41 85 5.2
Culvert 18 18 2.26 88 5.6 18 4.8
Total 17-18 10.8
Culvert 19 19 1.62 88 4.0 18 4.8
Culvert 20 + 215 20-23
(Apache
Canyon)
7,601 86 817.9 18
47.8
Culvert 225 26.4
Culvert 236
Total (Apache Canyon)1 7,601 - 817.9 - 74.2
Culvert 24 24 25.54 87 58.4 18 22.1
Culvert 254 25 18.32 87 41.9
Culvert 26A, 26B1 26 34.28 86 67.1 18 18.3
Total 25-26 109.0
Culvert 27A, 27B, 27C1 27 29.82 83 49.5 18 31.6
Notes:
1 Culverts are in series the Culvert Max Discharge is the smaller of the culverts as calculated.
2 Culverts show a combined capacity for Culvert Max Discharge
3 Culverts are a combination of in series and multiple culverts and Culvert Max Discharge is calculated per notes 1 and 2 as applicable
4 Culvert does not appear to exist for this watershed. The Culverts in the next watershed downstream are assumed to convey the flow.
5 Culverts 20, 21, and 22 provide outlet one large watershed (Apache Canyon) which is much larger than the other watersheds.
The existing culverts may be adequate if there is sufficient detention. Insufficient data for detention evaluation. Further
evaluation of flooding may be needed if culverts are replaced with larger structures.
6 Culvert 23 drains water from the rail bed to Culvert 22.
Assumptions:
 Curve Numbers for hydrologic analysis range from 83 to 88 depending on the soils present in the USGS online soil survey.
 Shape of existing culverts is assumed to be circular.
 Culverts are Corrugated Metal Pipe (CMP), with a Manning's n of 0.024.
 Culvert inlets are assumed to be projecting with kinetic energy (Ke) of 0.90.
 Head Water, invert elevations, and culvert lengths roughly estimated using topography provided by Allegiance in AutoCAD.
 Empirical observation indicates that the rail bed is not eroded, which would imply the existing culverts are adequate for
typical and frequent storms.
 Culverts may be silted in analysis did not account for this factor.