20240122_Culvert_Report

Enka Quarry•Mining Permit No. 11-03 Vulcan Construction Materials,LLC
Mining Permit Modification—November 14,2023
Temporary Access Road West Culvert
The Temporary Access Road West Culvert is designed to convey runoff from the 38 acres
of upland drainage area. The Culvert will be installed according to the requirements of the
included construction specifications and maintenance plans Culverts and OUTLET PROTECTION.
Watershed Modeling
The SCS method was utilized to predict surface runoff. The included design
calculations describe input data used in the method to determine and peak discharge.
Design Storm Events
The Culvert is designed to safely pass the peak flow of runoff from a 25 year — 24-hour
storm. The peak outflow for the 25 year—24-hour storm is 39.56 cfs. Please refer to the design
computations.

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Jan 16 2024
Circular Culvert
Invert Elev Dn (ft) = 2205.00 Calculations
Pipe Length (ft) = 100.00 Qmin (cfs) = 25.00
Slope (%) = 3.50 Qmax (cfs) = 40.00
Invert Elev Up (ft) = 2208.50 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 24.0
Shape = Circular Highlighted
Span (in) = 24.0 Qtotal (cfs) = 40.00
No. Barrels = 1 Qpipe (cfs) = 40.00
n-Value = 0.012 Qovertop (cfs) = 0.00
Culvert Type = Circular Culvert Veloc Dn (ft/s) = 12.76
Culvert Entrance = Smooth tapered inlet throat Veloc Up (ft/s) = 12.81
Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 HGL Dn (ft) = 2206.98
HGL Up (ft) = 2210.45
Embankment Hw Elev (ft) = 2213.44
Top Elevation (ft) = 2215.00 Hw/D (ft) = 2.47
Top Width (ft) = 50.00 Flow Regime = Inlet Control
Crest Width (ft) = 100.00

1
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Tuesday,01 /16/2024
Hyd. No. 1
Culvert Watershed
Hydrograph type = SCS Runoff Peak discharge = 25.94 cfs
Storm frequency = 10 yrs Time to peak = 12.43 hrs
Time interval = 2 min Hyd. volume = 172,269 cuft
Drainage area = 38.000 ac Curve number = 60
Basin Slope = 6.7 % Hydraulic length = 2874 ft
Tc method = LAG Time of conc. (Tc) = 49.56 min
Total precip. = 4.91 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Culvert Watershed
Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

2
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Tuesday,01 /16/2024
Hyd. No. 1
Culvert Watershed
Hydrograph type = SCS Runoff Peak discharge = 39.56 cfs
Storm frequency = 25 yrs Time to peak = 12.40 hrs
Time interval = 2 min Hyd. volume = 246,306 cuft
Drainage area = 38.000 ac Curve number = 60
Basin Slope = 6.7 % Hydraulic length = 2874 ft
Tc method = LAG Time of conc. (Tc) = 49.56 min
Total precip. = 5.79 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Culvert Watershed
Q (cfs) Hyd. No. 1 --25 Year Q (cfs)
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

24 u C Appendices
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3 5 10 20 50 100 200 500 1000
Dis arge(ft3/sec)
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Curves may not be extrapolated. 40
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Ti<0.5 diameter).
Rev.12/93 8.06.3