SW3240702_Design Calculations_20240801

ENGINEFRINGDAYLIGHT
Stormwater Calculations
For
Performance Precast
11 Zane Road
Midland, NC 28107
Project No: 23042
Client: RNH Incorporated
Client Representitive: Randy Humphrey
18636 Starcreek Drive
Cornelius, NC 28031
P: 704.281.8472
[e-mail]
Preparer's Name: Kate Underwood, PhD, PE
Daylight Engineering PLLC '.sio''-/''��
NCBELS Corporate License Number P-2772 �'!^9
165 Brumley Ave NE 033470 o
Concord, NC 28025 6.2 .
980.234.7500
[e-mail] '""�" ��\

Table of Content
- Narrative and Summary of Results
- Impervious Area Summary
- Pre-Development Calculations
- Pre Development Nodal Diagram
- Pre-Development Drainage Areas
- Post-Development Calculations
- Post-Development Nodal Diagram
- Post-Development Drainage Areas
- Wet Detention Pond Calculations
- Hydraflow Results
- Riprap Calculations %\�.� c •�'��,,�
• 11 /
- Appendix 'r'l.
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165 Brumley Ave NE
DAYL I G H T � �,' Conc 980.234 7500
ENGINEERING
daylighteng.com
Performance Precast
Stormwater Narrative
Existing Conditions:
The project site is located at 11 Zane Road in Midland, NC in Cabarrus County. The site is located on one of the lots
of the recently constructed Smith Industrial Subdivision. A web soil survey found soils on the to be made up of Tarrus
silt loam — Hydrologic Soil Group B, Herndon silt loam — Hydrologic Soil Group B, Kirksey silt loam — Hydrologic Soil
group C, and Chewacla sandy loam — Hydrologic Soil Group D. There is no existing on-site impervious area.
Proposed Improvements:
The proposed project consists of the construction of one building, a asphalt driveway and parking lot, and a gravel
lot. The lot will be curbed and will contain a batch plan and washout pit with a 39,770 sf warehouse. A sidewalk is
proposed along the asphalt driveway and the building will be served by a septic system and will be sprinkled.
Stormwater Treatment:
To provide treatment and attenuation for the site, a wet pond stormwater control measure (SCM) is proposed.
Stormwater will be collected by storm drainage systems that will drain into the wet pond to be treated.
The required treatment volume was calculated using the Simple Method for Runoff Volume.
June 20, 2024 9

SUMMARY OF RESULTS
PRE-DEVELOPMENT DRAINAGE AREA SUMMARY
DRAINAGE AREA AREA(ACRES) TC CN
Pre DA-A 11.663 10.70 57.1
Total 11.663
POST DEVELOPMENT DRAINAGE AREA SUMMARY
DRAINAGE AREA AREA(ACRES) TC CN
Post DA-1 9.607 10.00 82.8
Post DA-2 2.056 10.00 66.1
Total 11.663
PRE-DEVELOPMENT RUNOFF RESULTS
DRAINAGE AREA 1 YR/24 HR 10 YR/24 HR 100 YR/24 HR
Pre DA-A 1.38 17.71 45.11
Outfall 98-W 1.38 17.71 45.11
POST-DEVELOPMENT RUNOFF RESULTS
DRAINAGE AREA 1 YR/24 HR 10 YR/24 HR 100 YR/24 HR
Post DA-1 18.70 44.69 75.18
Post DA-2 1.20 5.24 10.95
Wet Pond 1 0.66 8.64 56.84
Outfall 99-W 1.30 9.97 65.26
POST DEVELOPMENT PEAK-STAGE RESULTS
1 YR/24 HR 10 YR/24 HR 100 YR/24 HR
WP1 (T.O.B. = 653) 649.79 651.12 651.90

3. Impervious Area Summary
Pre-Development
Total Existing On-Site inpervious area 0 SQ FT
Post-Development
Total on-site impervious area 317,324 SQ FT
On-site area required to be treated by SCM 317,324 SQ FT1
Total area treated by SCM 317,324 SQ FT
Equal to the post-development impervious area minus the Pre-devlopment Impervious area
Disturbed Soil Summary
Type B Type C Type D
Pre-Development(sf) 455,204 52,216 626
Post-Development(sf) 455,204 52,216 626

Pre Development Nodal Diagram
PRE DA-A
/ALL
W

Pre-Development Drainage Area A
Land use Condition Hydrologic Area(SF) Area(Acres) Cn Weighted Cn
Soil Group — —
Woods good B 429,690 9.864 55 46.5
Impervious n/a B 2,661 0.061 98 0.5
Open Space good B 22,853 0.525 61 2.7
Woods good C 52,216 1.199 70 7.2
Woods good D 626 0.014 77 0.1
508,046 11.663 57.1
tc Calculation L up down slope n pipe size(in) area(sf) perimeter
_ (ft)
Sheet Flow 100 692.52 686.36 6.16% 0.15 Grass:Short Praire
Shallow Concentrated 745 686.36 651.50 4.68% Un-Paved
CALCULATED TC= 10.70 MIN SEE HYDRAFLOW TR-55 TC CALCULATION SHEET
TC USED IN CALCULATION= 10.70 MIN MINIMUM TC OF 10 MINUTES
Roughness Coefficients(Manning's N)for Sheet Flow
Smooth Surfaces(Concrete,asphalt,gravel,or bare soil) 0.011
Fallow(no residue) 0.05
Cultivated Soils,Residue<=20% 0.06
Cultivated Soils,Residue>20% 0.17
Grass:Short Praire 0.15 4
Grass:Dense Grass 0.24
Grass:Bermuda Grass 0.41
Range:Natural 0.13
Woods:Light Underbrush 0.4
Woods:Dense Underbrush 0.8
Roughness Coefficients(Manning's N)for Channel Flow
Excavated Channels:Short Grass 0.027

TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. No. 1
PRE DA-A
Description A B C Totals
Sheet Flow
Manning's n-value = 0.150 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 2.45 0.00 0.00
Land slope (%) = 6.16 0.00 0.00
Travel Time (min) = 7.14 + 0.00 + 0.00 = 7.14
Shallow Concentrated Flow
Flow length (ft) = 745.00 0.00 0.00
Watercourse slope (%) = 4.68 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) =3.49 0.00 0.00
Travel Time (min) = 3.56 + 0.00 + 0.00 = 3.56
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc 10.70 min

Post Development Nodal Diagram
Post DA-1
Post DA-2
WP1
OUTFALL
99-W

Post-Development Drainage Area 1
Land use Condition Hydrologic Area(SF) Area(Acres) Cn Weighted Cn
Soil Group _
Open Space good B 81,923 1.881 61 11.9
Impervious:Gravel N/A B 218,462 5.015 85 44.4
Impervious N/A B 9S 858 2.201 98 22.4
Open Space good C 19,249 0.442 74 3.4
Impervious:Gravel N/A C 2,468 0.057 89 0.5
Impervious N/A C 536 0.012 98 0.1
418,496 9.607 82.8
TC USED IN CALCULATION= 10.00 MIN MINIMUM TC OF 10 MINUTES

Wet Detention Pond Design Calculations
Area(sq.ft.) Area(acres) Attenuation Requirements
Total Drainage Area(sf) 418,496 9.607 1-year,24-hour storm
Pervious Area(sf) 101,172 2.323 10-year,24-hour storm
Impervious Area(sf) 317,324 7.285 Emergency Spillway Requirement
100 year,24-hour storm,6"freeboard
Simple Method for Runoff Volume
Rv=0.05+0.9*IA 0.73 Rv=Runoff Coefficient(unitless)
IA=Impervious fraction 0.76
DV=3630*RD*Rv*A 25,543 DV=Design Volume(cu ft)
RD=Design Storm Depth(in) 1.0
A=Drainage Area(ac) 9.607 ac
Average Depth of Main Pool Double Interpolation from SA/DA Table
Devg=Vpp/App 3.94 3.00 3.94 4.00
0.70 2.51 2.11 2.09
Vpp=Volume of permanent pool(Main Body only) 44,801 (ft3) 0.76 2.30
App=Area of permanent pool(Main Body only) 11,365 (sf) 0.80 2.92 2.44 2.41
Main Pool Volume(SA/DA Method)
Total DA 418,496 (sf)
SA/DA 2.30
Surface Area Required(DA*((SA/DA)/100)) 9,641 (sf)
Surface Area Provided(Main Body only) 11,365 (sf)
Table 1:Piedmont and Mountain SA/DA Table(Adapted from Driscoll,1986)
3.00 4.00 5.00 6.00 7.00 8.00
0.10 0.51 0.43 0.37 0.30 0.27 0.25
0.20 0.84 0.69 0.61 0.51 0.44 0.40
0.30 1.17 0.94 0.84 0.72 0.61 0.56
0.40 1.51 1.24 1.09 0.91 0.78 0.71
0.50 1.79 1.51 1.31 1.13 0.95 0.87
0.60 2.09 1.77 1.49 1.31 1.12 1.03
0.70 2.51 2.09 1.80 1.56 1.34 1.17
0.80 2.92 2.41 2.07 1.82 1.62 1.40
0.90 3.25 2.64 2.31 2.04 1.84 1.59
1.00 3.55 2.79 2.52 2.34 2.04 1.75
Minimum Water Quality Elevation Interpolation
Design Volume(DV) 25,543 (ft3) 649.00 16,581
Minimum Water Quality Elevation(ft) 649.47 649.47 25,543
Water Quality Elevation(ft) 649.50 650.00 35,718
Permanent Pool Elevation(ft) 648.00
Provided Water Quality Volume 26,150 (ft3) Provided Water Quality Volume Interpolation
649.00 16,581
649.50 26,150
650.00 35,718
Orifice Size
Treatment Vol 26,150 CF 26,150
Draw Down Time 2 DAYS 5
Draw Down Time 172,800 sec 432,000
Flow(Q) 0.151 CFS 0.061
Cd 0.6 0.6
H/3 0.500 ft 0.500
Area of orifice 0.044 sf 0.018 Pipe Embed 6
Dia. 2.86 in 1.81 < Plate Hole: 2
Center Offse 2
Draw Down Time: 4.08 days
Draw Down Rate: 0.07 cfs

Permanent Pool
Main Body Forebay
Incremental Cumulative Incremental Cumulative
Elevation (ft) Area (sf) Depth (ft) Volume (sf) Volume(sf) Elevation (ft) Area (sf) Depth (ft) Volume(sf) Volume(sf)
641.00 2,945 - - - 644.00 1,342 - - -
642.00 3,946 1.00 3,446 3,446 645.00 1,803 1.00 1,573 1,573
642.00 1 3,946 1 - - -
643.00 5,012 1.00 4,479 4,479 645.00 1,803 - - - _
644.00 6,159 1.00 5,586 10,065 646.00 2,331 1.00 2,067 2,067_
645.00 7,367 1.00 6,763 16,828 647.00 2,926 1.00 2,629 4,696
646.00 8,637 1.00 8,002 24,830 648.00 3,588 1.00 3,257 7,953
647.00 9,970 1.00 9,304 34,133
648.00 11,365 1.00 10,668 44,801
Temporary Pool
I
Incremental I Cumulative
Elevation (ft) Area (sf) Depth (ft) Volume (sf) Volume(sf)_
Orifice elevation/permanent pool 648.00 14,953 - - -
649.00 18,209 1.00 16,581 16,581
650.00 20,065 1.00 19,137 35,718
651.00 21,977 1.00 21,021 56,739_
652.00 23,946 1.00 22,962 79,701
653.00 25,971 1.00 24,959 104,659
Combined Permanent Pool Volume: 52,753 (Main Body 44,801+Forebay 7,953)
Forebay Volume: 7,953
Forebay Percentage 15.1%

WP DS1
JOB NO.: 23042.000 BY: AM
DATE: 5/22/2024 P.M: KWU
REVISED: FLOATATION CALCULATIONS
Calculations Given Data Standard Footing Assumptions
Density of Concrete 150 Ibs/ft^3 1.Footing base to be 1 ft.wider than structure
Density of Water 62.4 Ibs/ft^3 on all sides.
Safety Factor(S.F.) 2
Equations used:
Outlet Structure Weight,W(s)= (w+2t)^2`h-w^2`(h-t)x D(c)
where, w= outlet box inside dimension,ft.
Displaced Water Weight,W(w)= (w+2t)^2 x D(w)x h t= structure wall thickness,ft.
h= height of structure,ft.
Required Base Weight,W(b)= (W(w)x S.F.)-W(s) D(c)= density of concrete,lbs/ft^3
D(w)= density of water,Ibs/ft^3
Required Footing Volume, V(f)= W(b)/Dc-Dw S.F.= safety factor
WDP I Outlet Structure
Structure Dimensions Object Weights
Elevation at bottom of structure= 641.00
Elevation at top of structure= 651.00
Height of structure,h= 10.00 ft. Outlet Structure Weight, W(s)= 11175 lbs
Structure wall thickness,t= 6 in. Displaced Water Weight, W(w)= 9984 lbs
Average outlet box inside dimension, w= 3 ft. Req'd Base Weight, W(b)= 8793 lbs
Footing Size
Required Footing Volume, V(fr)= 100 cf Standard Footing Length,L= 6.00 ft.
Provided Footing Volume, V(fp)= 108 cf Standard Footing Width, W= 6.00 ft.
Footing Check okay Minimum Footing Depth,D= 1.00 ft.
Footing Size to be used: Length= 6.00 ft.
Width= 6.00 ft.
Depth= 3.00 ft.

Post-Development Drainage Area 2
Land use Condition Hydrologic Area(SF) Area(Acres) Cn Weighted Cn
Soil Group
Open Space good B 47,566 1.092 61 32.4
Woods good B 8,548 0.196 55 5.3
Impervious n/a B 2,847 0.065 98 3.1
Open Space good C 29,963 0.688 74 24.8
Open Space good D 626 0.014 80 0.6
89,550 2.056 66.1
TC USED IN CALCULATION= 10.00 MIN MINIMUM TC OF 10 MINUTES

Hydraflow Results

Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
1 2 3
ELD
41110
i°
5
Legend
Hyd. Origin Description
1 SCS Runoff PRE DA-A
2 SCS Runoff POST DA-1
3 SCS Runoff POST DA-2
4 Reservoir POST DA-1 >Wet Pond
5 Combine OUTFALL 99-W
Project: 23042 Stormwater Calculations.gpw Monday, 06/24/2024

Hydrograph Return Period Recap Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph
No. type hyd(s) Description
(origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
1 SCS Runoff 1.376 17.71 45.11 PRE DA-A
2 SCS Runoff 18.70 44.69 75.18 POST DA-1
3 SCS Runoff 1.202 5.244 10.95 POST DA-2
4 Reservoir 2 0.656 8.642 56.84 POST DA-1 >Wet Pond
5 Combine 3,4 1.297 9.970 65.26 OUTFALL 99-W
Proj. file: 23042 Stormwater Calculations.gpw Monday, 06/24/2024

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
I
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 1.376 2 726 9,567 PRE DA-A
2 SCS Runoff 18.70 2 720 48,664 POST DA-1
3 SCS Runoff 1.202 2 722 3,861 POST DA-2
4 Reservoir 0.656 2 906 43,925 2 649.79 31,677 POST DA-1 >Wet Pond
5 Combine 1.297 2 722 47,786 3,4 OUTFALL 99-W
23042 Stormwater Calculations.gpw Return Period: 1 Year Monday, 06/24/2024

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 1
PRE DA-A
Hydrograph type = SCS Runoff Peak discharge = 1.376 cfs
Storm frequency = 1 yrs Time to peak = 726 min
Time interval = 2 min Hyd. volume = 9,567 cuft
Drainage area = 11.663 ac Curve number = 57.1
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.70 min
Total precip. = 2.90 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
PRE DA-A
Q (cfs) Hyd. No. 1 -- 1 Year Q (cfs)
2.00 2.00
1.00 - 1 1.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 2
POST DA-1
Hydrograph type = SCS Runoff Peak discharge = 18.70 cfs
Storm frequency = 1 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 48,664 cuft
Drainage area = 9.607 ac Curve number = 82.8
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 2.90 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
POST DA-1
Q (cfs) Hyd. No. 2 -- 1 Year Q (cfs)
21.00 21.00
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 - - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 3
POST DA-2
Hydrograph type = SCS Runoff Peak discharge = 1.202 cfs
Storm frequency = 1 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 3,861 cuft
Drainage area = 2.056 ac Curve number = 66.1
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 2.90 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
POST DA-2
Q (cfs) Hyd. No. 3 -- 1 Year Q (cfs)
2.00 2.00
1.00 - 1.00
0.00 - P - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 4
POST DA-1 > Wet Pond
Hydrograph type = Reservoir Peak discharge = 0.656 cfs
Storm frequency = 1 yrs Time to peak = 906 min
Time interval = 2 min Hyd. volume = 43,925 cuft
Inflow hyd. No. = 2 - POST DA-1 Max. Elevation = 649.79 ft
Reservoir name = Wet Pond Max. Storage = 31,677 cuft
Storage Indication method used.
POST DA-1 > Wet Pond
Q (cfs) Hyd. No. 4 -- 1 Year Q (cfs)
21.00 21.00
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 4 Hyd No. 2 111111111 Total storage used = 31,677 cuft

Pond Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Pond No. 1 - Wet Pond
Pond Data
Contours-User-defined contour areas.Average end area method used for volume calculation.Begining Elevation=648.00 ft
Stage/Storage Table
Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft)
0.00 648.00 14,953 0 0
1.00 649.00 18,209 16,581 16,581
2.00 650.00 20,065 19,137 35,718
3.00 651.00 21,977 21,021 56,739
4.00 652.00 23,946 22,962 79,701
5.00 653.00 25,971 24,959 104,659
Culvert/Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise(in) = 36.00 2.00 0.00 0.00 Crest Len(ft) = 11.00 1.00 15.00 0.00
Span(in) = 36.00 2.00 0.00 0.00 Crest El.(ft) = 651.00 649.50 651.50 0.00
No.Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33
Invert El.(ft) = 643.50 648.00 0.00 0.00 Weir Type = 1 Rect Ciplti ---
Length(ft) = 101.00 0.50 0.00 0.00 Multi-Stage = Yes Yes No No
Slope(%) = 0.50 0.50 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Contour)
Multi-Stage = n/a Yes No No TW Elev.(ft) = 0.00
Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s).
Stage/Storage/Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
0.00 0 648.00 0.00 0.00 --- --- 0.00 0.00 0.00 --- --- --- 0.000
1.00 16,581 649.00 53.83 oc 0.10 ic --- --- 0.00 0.00 0.00 --- 0.101
2.00 35,718 650.00 53.83 oc 0.15 ic --- --- 0.00 1.18 0.00 --- --- --- 1.323
3.00 56,739 651.00 53.83 oc 0.18 ic --- --- 0.00 6.12 0.00 --- --- --- 6.297
4.00 79,701 652.00 53.83 oc 0.21 ic --- --- 36.63 13.16 17.66 --- --- 67.66
5.00 104,659 653.00 78.49 is 0.17 is --- --- 57.50 ic 20.82 s 91.76 --- --- 170.26

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 5
OUTFALL 99-W
Hydrograph type = Combine Peak discharge = 1.297 cfs
Storm frequency = 1 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 47,786 cuft
Inflow hyds. = 3, 4 Contrib. drain. area = 2.056 ac
OUTFALL 99-W
Q (cfs) Hyd. No. 5-- 1 Year Q (cfs)
2.00 2.00
1.00 - 1.00
0.00 J 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 5 Hyd No. 3 Hyd No. 4

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 17.71 2 722 50,853 PRE DA-A
2 SCS Runoff 44.69 2 720 116,715 POST DA-1
3 SCS Runoff 5.244 2 722 13,883 POST DA-2
4 Reservoir 8.642 2 736 111,702 2 651.12 59,503 POST DA-1 >Wet Pond
5 Combine 9.970 2 734 125,585 3,4 OUTFALL 99-W
23042 Stormwater Calculations.gpw Return Period: 10 Year Monday, 06/24/2024

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 1
PRE DA-A
Hydrograph type = SCS Runoff Peak discharge = 17.71 cfs
Storm frequency = 10 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 50,853 cuft
Drainage area = 11.663 ac Curve number = 57.1
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.70 min
Total precip. = 5.10 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
PRE DA-A
Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 - • 1 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 2
POST DA-1
Hydrograph type = SCS Runoff Peak discharge = 44.69 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 116,715 cuft
Drainage area = 9.607 ac Curve number = 82.8
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 5.10 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
POST DA-1
Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 3
POST DA-2
Hydrograph type = SCS Runoff Peak discharge = 5.244 cfs
Storm frequency = 10 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 13,883 cuft
Drainage area = 2.056 ac Curve number = 66.1
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 5.10 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
POST DA-2
Q (cfs) Hyd. No. 3 -- 10 Year Q(cfs)
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
J L
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 4
POST DA-1 > Wet Pond
Hydrograph type = Reservoir Peak discharge = 8.642 cfs
Storm frequency = 10 yrs Time to peak = 736 min
Time interval = 2 min Hyd. volume = 111,702 cuft
Inflow hyd. No. = 2 - POST DA-1 Max. Elevation = 651.12 ft
Reservoir name = Wet Pond Max. Storage = 59,503 cuft
Storage Indication method used.
POST DA-1 > Wet Pond
Q (cfs) Hyd. No. 4 -- 10 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
—
0.00 — . 0.00
0 360 720 1080 1440 1800 2160 2520 2880 3240 3600 3960
Time (min)
Hyd No. 4 Hyd No. 2 111111111 Total storage used = 59,503 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 5
OUTFALL 99-W
Hydrograph type = Combine Peak discharge = 9.970 cfs
Storm frequency = 10 yrs Time to peak = 734 min
Time interval = 2 min Hyd. volume = 125,585 cuft
Inflow hyds. = 3, 4 Contrib. drain. area = 2.056 ac
OUTFALL 99-W
Q (cfs) Hyd. No. 5-- 10 Year Q (cfs)
10.00 - 10.00
8.00 8.00
6.00 - 6.00
4.00 - 4.00
2.00 2.00
0K------ ---.....-
0.00 - ' ' 0.00
0 360 720 1080 1440 1800 2160 2520 2880 3240
Time (min)
Hyd No. 5 Hyd No. 3 Hyd No. 4

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 45.11 2 722 119,259 PRE DA-A
2 SCS Runoff 75.18 2 720 200,428 POST DA-1
3 SCS Runoff 10.95 2 720 28,425 POST DA-2
4 Reservoir 56.84 2 726 195,273 2 651.90 77,479 POST DA-1 >Wet Pond
5 Combine 65.26 2 726 223,697 3,4 OUTFALL 99-W
23042 Stormwater Calculations.gpw Return Period: 100 Year Monday, 06/24/2024

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 1
PRE DA-A
Hydrograph type = SCS Runoff Peak discharge = 45.11 cfs
Storm frequency = 100 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 119,259 cuft
Drainage area = 11.663 ac Curve number = 57.1
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.70 min
Total precip. = 7.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
PRE DA-A
Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs)
50.00 50.00
40.00 40.00
1
30.00 30.00
20.00 20.00
10.00 10.00
0.00 - - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 2
POST DA-1
Hydrograph type = SCS Runoff Peak discharge = 75.18 cfs
Storm frequency = 100 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 200,428 cuft
Drainage area = 9.607 ac Curve number = 82.8
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 7.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
POST DA-1
Q (cfs) Hyd. No. 2 -- 100 Year Q (cfs)
80.00 80.00
70.00 70.00
1
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
—
10.00 10.00
0.00 7"�� • 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 3
POST DA-2
Hydrograph type = SCS Runoff Peak discharge = 10.95 cfs
Storm frequency = 100 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 28,425 cuft
Drainage area = 2.056 ac Curve number = 66.1
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 7.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
POST DA-2
Q (cfs) Hyd. No. 3 -- 100 Year Q (cfs)
12.00 12.00
10.00 — 10.00
8.00 — 8.00
6.00 I — 6.00
4.00 4.00
2.00 2.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 4
POST DA-1 > Wet Pond
Hydrograph type = Reservoir Peak discharge = 56.84 cfs
Storm frequency = 100 yrs Time to peak = 726 min
Time interval = 2 min Hyd. volume = 195,273 cuft
Inflow hyd. No. = 2 - POST DA-1 Max. Elevation = 651.90 ft
Reservoir name = Wet Pond Max. Storage = 77,479 cuft
Storage Indication method used.
POST DA-1 > Wet Pond
Q (cfs) Hyd. No. 4 -- 100 Year Q (cfs)
80.00 80.00
I
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
iL---...........
20.00 20.00
10.00 10.00
0.00 - a 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 4 Hyd No. 2 111111111 Total storage used = 77,479 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Hyd. No. 5
OUTFALL 99-W
Hydrograph type = Combine Peak discharge = 65.26 cfs
Storm frequency = 100 yrs Time to peak = 726 min
Time interval = 2 min Hyd. volume = 223,697 cuft
Inflow hyds. = 3, 4 Contrib. drain. area = 2.056 ac
OUTFALL 99-W
Q (cfs) Hyd. No. 5 -- 100 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 - - 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 5 Hyd No. 3 Hyd No. 4

Hydraflow Rainfall Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Monday,06/24/2024
Return Intensity-Duration-Frequency Equation Coefficients(FHA)
Period
(Yrs) B D E (N/A)
1 64.6880 13.0000 0.9002
2 66.7847 12.4000 0.8642
3 0.0000 0.0000 0.0000
5 75.2703 13.0000 0.8421
10 71.9699 12.4000 0.8031
25 61.9247 11.0000 0.7384
50 56.4944 10.1000 0.6971
100 50.2401 9.0000 0.6526
File name:Concord IDF.IDF
Intensity= B/(Tc+ D)^E
Return Intensity Values(in/hr)
Period
(Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60
1 4.80 3.85 3.22 2.78 2.45 2.19 1.98 1.81 1.67 1.55 1.45 1.36
2 5.66 4.55 3.82 3.31 2.92 2.62 2.38 2.18 2.02 1.88 1.76 1.65
3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
5 6.60 5.37 4.55 3.96 3.52 3.17 2.89 2.66 2.46 2.30 2.15 2.03
10 7.26 5.93 5.04 4.41 3.93 3.55 3.25 2.99 2.78 2.60 2.45 2.31
25 7.99 6.54 5.59 4.90 4.39 3.99 3.66 3.40 3.17 2.98 2.81 2.66
50 8.51 6.98 5.97 5.26 4.73 4.31 3.97 3.69 3.45 3.25 3.07 2.92
100 8.98 7.35 6.31 5.58 5.03 4.60 4.25 3.96 3.72 3.51 3.33 3.17
Tc=time in minutes.Values may exceed 60.
Precip.file name:Z:\23031 171 Cabarrus\5.Engineering Calculations\4.Stormwater Calculations\Concord.pcp
Rainfall Precipitation Table (in)
Storm
Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
SCS 24-hour 2.90 3.50 0.00 4.40 5.10 6.00 6.80 7.60
SCS 6-Hr 2.06 0.00 0.00 3.09 0.00 4.21 4.72 0.00
Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Riprap

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JAM Date: 6/20/2024
Checked By: NDB
Company: Daylight Engineering
Project Name: Performance Precast
Project No.: 23042.000
Site Location (City/Town) Midland
Culvert Id. FES-1
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified minimum tailwater condition.
If it is greater than half the pipe diameter. it is classified ma.Xinnum condition.
Pipes that outlet onto wide fiat areas with no defined channel are asstuned
to have a mnllnnun tailwater condition unless reliable flood stage elevations
show Otherwise.
Outlet pipe diameter, Do (in.) 36
Tailwater depth (in.) 0
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 43.61 See 10 year HGLE Calculation results
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determined riprap size and minimum apron length
(La). The d;0 size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.

Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.6
Minimum apron length, La (ft.) 20
Apron width at pipe outlet (ft.) 9 9
Apron shape Trapezoidal
Apron width at outlet end (ft.) 23 3
Step 4. Determine the maximum stone diameter:
dr.„ = 1.5 x d50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.9 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x d Use class B riprap
Minimum TW Maximum TW
Apron Thickness(ft.) 1.35 0
RIP RAP CLASS MINIMUM MIDRANGE MAXIMUM
A 2 IN (0.17 FT) 4 IN (0.33 FT) 6 IN (0.5 FT)
B 5 IN (0.42 FT) 8 IN (0.67 FT) 12 IN (1 FT)
1 5 IN (0.42 FT) 10 IN (0.83 FT) 17 IN (1.42 FT)
2 9 IN (0.75 FT) 14 IN (1.17 FT) 23 IN (1.92 FT)
Step 6. Fit the riprap apron to the site by making it level for the minimum
length. L,. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
unto the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix 8.05). Where overfills exist at
pipe outlets or flows are excessive, a plunge pool should be considered, see
page 8.06.8.

3 0
Outlet W • Do + 1-a 90 ,. . •
pipe •�,
C.diameter (Do) i ;...: •: :
La .1
atlwater c 0.5D0 - I 1i1iiif 11 a iifii.l, ,�•rr/ ?i
c I �` I'''I�ij
Pp 60 _ '' i�ICl, ii,' .
�e(‘� i y �/lt• :::::...1
Min lt I fI : .... o o ''A ,. ",I•yipAl'i l'�{��..:..'• %4
t.I , Itl HIIr1 44,411
11IIIII1' i ' NI`ll I�l�lj n i ::i iil n II 11111 " t' i1I IIIImIN �' fA /... :1C��I I II�:: �I. n
III I I1I��MM Illlrrlllll , fir ... : 1111 1 I :: ®� �I'4
:. r•1111 grlIllt � -fi ��® 1117
1r111 :109(
__ iullnn I rrrur r•uuua Ii
Ar -..Atie
nuuuunui�
. ..,.._"...„....„ . .... .
....
4 iiii*Ford".,,.., . s
•
0 I NH"
rllll llllrllll ll I :. 1111 - _ O _ , fr '.b 2 N
I 1 WIN -
1 Arli I I 1�Ir11111 I ,� 1 _ion,. d
rrAMli I'tilllIl lit I i 1 ,. •'�' �J i IMII III e
Hi,
AI IIA■IMI'I MI���Illlrllilll l�� 11�� dl j. ,... .. �� - .�
.. ..
cc
• _.. /iijoie IIPP, AI ii llnu
r III nl ``I III rulnlu _� .. :. V ,K,
s 2 • , �' I - _Q
il��rinl - . . . . .. .
�l1�
• •• v .20
\5 a'/-r��' P%1.1r/� .. 1.
, d50=0.60 D
. I v 15 .r_-�/..amioniiiiigli
• ,l
ilIIflhII
ce►'
0
3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
43.61 cfs
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Tw<0.5 diameter)
Ref-.1243 8.06.3

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JAM Date: 6/24/2024
Checked By: NDB
Company: Daylight Engineering
Project Name: Performance Precast
Project No.: 23042.000
Site Location (City/Town) Midland
Culvert Id. FES-2
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter.it is classified minimum tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide fiat areas with no defined channel are assumed
to have a muunntum tailwater condition unless reliable flood stage elevations
show otherwise.
Outlet pipe diameter, Do (in.) 36
Tailwater depth (in.) 0
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 8.64 See 10 year Stormwater Calculation results
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d;,,riprap size and minimum apron length
(La). The d;, size is the median stone size in a well-graded nprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.

Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.6
Minimum apron length, La (ft.) 20
Apron width at pipe outlet (ft.) 9 9
Apron shape Trapezoidal
Apron width at outlet end (ft.) 23 3
Step 4. Determine the maximum stone diameter:
dfr,x = 1.5 x duo
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.9 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x d„„ Use class B riprap
Minimum TW Maximum TW
Apron Thickness(ft.) 1.35 0
RIP RAP CLASS MINIMUM MIDRANGE MAXIMUM
A 2 IN (0.17 FT) 4 IN (0.33 FT) 6 IN (0.5 FT)
B 5 IN (0.42 FT) 8 IN (0.67 FT) 12 IN (1 FT)
1 5 I N (0.42 FT) 10 IN (0.83 FT) 17 I N (1.42 FT)
2 9 IN (0.75 FT) 14 IN (1.17 FT) 23 IN (1.92 FT)
Step 6. Fit the riprap apron to the site by making it level for the nummnumi
length. La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stabilin•.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix 5.05). Where overfills exist at
pipe outlets or flows are excessive, a plunge pool should be considered, see
page 8.06.8.

3 0 _
Outlet w . Do + La
pipe
{ . ri
diameter (Do)
La --.I AO - :A
iiiiiitii later 0.5D0 : . .. I
�r'r r.
,... . . , . E1� _ 4.j is .
g`ro0P 6a b
l _ ::: : : , _ li i a. :i.,/ , ,:..b lb 4. . .
40 , Y . ■, A.t.41.
Ia=20 '1 ..... ..tplr..,
mom ti : � L 4 ' 4 ' ` �IIMIII' •
. J'' /,
3Q I •UII ■ •-. • i Itlilli
Aft
O! *. ZIA.'
10
J � �/.7',71.4.4.1.4'I.. AI — ' 4two-5:10
� ;1,
0 — .".**.*: : - -AV), 1;4
.`.11:14 2 ch
��.�&, II 5�.. Air "Iris a
firc i
v = is _ -, r ,.. d50=0.60 ,
ram//✓��.-
- .
0
3 5 10 20 50 100 200 500 1000
1
8.64 cfs 1 Discharge(ft3/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Tv„<0.5 dameter)
Rev.12 93 8.06.3

Appendix

Table 4: HSGs for North Carolina Soil Types *
Urban areas runoff curve numbers fro SCS method (SCS 1986)
Cover Description Curve Number by HSG
A B f C D
Fully developed urban areas
Open Space (lawns, parks,golf courses, etc.)
Poor Condition (<50%Grass Cover) 68 79 86 89
Fair Condition (50%to 75%Grass Cover) 49 69 79 84
Good Condition (>75%Grass Cover) 39 61 74 80
Impervious areas:
Paved parking lots, roofs, driveways, etc.) 98 98 98 98
Streets and roads:
Paved; curbs and storm sewers 98 98 98 98
Paved; open ditches 83 89 98 98
Gravel 76 85 89 91
Dirt 72 82 85 88
Developing Urban Areas
Newly graded areas 77 86 91 94
_ Pasture (<50%ground cover or heavily grazed) 68 79 86 89
_ Pasture (50%to 75%ground cover or not heavily grazed) 49 69 79 84
_ Pasture (>75%ground cover or lightly) 39 61 74 80
Meadow-continuous grass, protected from grazing and
generally mowed for hay 30 58 71 78
_ Brush (<50%ground cover) 48 67 77 83
Brush (50%to 75% ground cover) 35 56 70 77
Brush (>75%ground cover) 30 48 65 73
Woods (forest liter,small trees, and brush destroyed by heavy
grazing or regular burning 45 66 77 83
Woods (Woods are grazed but not burned, and some forrest
litter covers the soil) 36 60 73 79
Woods (Woods are protected from grazing, and litter and brush
adequately cover the soil) 30 55 70 77
*Table taken from NCDEQ Sormwater Design Manual Part B: Calculations Guidance, revised 3/5/2017

CEST
Civil - Geotechnical - Surveying
May 23, 2024
Mr. Randy Humphries
Performance Precast, Inc.
Reference: Seasonal High-Water Table Determination
Proposed PPI Office and Welding Site
70 Zane Road
Midland, Cabarrus County, North Carolina
CESI Project Number 240260.000
Mr. Humphries:
In accordance with your request, Concord Engineering & Surveying, Inc. (CESI) has
performed an evaluation of seasonal high-water table (SHWT) on the above referenced
project. The SHWT was performed within the area of the proposed sand filter, as shown
below:
il
DS-1
RIM.693.00
15' INV OUT(N):686.53 0
d
Ilk :72C''
98.L
SHWT O
Test Location - cv
0
1Y) 1�
CO in rn co BUILDING F.F.E. 141.31'/15' RCP/0.501
cn< `O 698.50
r
i f J
FEs-1
INV OUT: 689.19
^ 161.51715.RCP 0.50E
'--r i
1 73.92718'RCP/0.50% -
\ __.,-
RIM-1 ��,
RIM:693.08 1�.\��
1•
6", /18" IN�(..OUTS(E)6 89.56` \ - `
45 Spring Street, SW P.O. Box 268 Concord, NC 28026-0268 704-786-5404
www.cesicgs.com NC License No. C-0263

On May 22, 2024, a CESI representative monitored the excavation and the soil horizon at the
above referenced location.At the proposed test location, a Hyundai 235 excavator owned and
operated by Randall Site Services, was used to excavate to a depth of 11' below existing
ground surface.
The soil horizon encountered at the excavation included:
• 2" of grass and topsoil,
• 15" of brown and gray moderately plastic silty CLAY (CL),
• 38" of brown, yellow and gray clayey SILT (ML) with sand and gravel,
• 67" of WEATHERED ROCK sampled as brown , yellow and gray SILT (ML) with
seams of harder WEATHERED ROCK
• No water was recorded at the time of excavation.
• No indications of groundwater were observed to the depths explored.
On May 23, 2023, CESI returned to the site to observe the conditions within the excavation.
No water was observed in the excavation. As a result of our site observations, we offer the
following:
Sand Filter Seasonal Hiqh-Water Table
Ground Elevation at Test Location Elevation 694.0
Bottom of Excavation Elevation 683.0
Water Level Elevation not encountered
Bottom of Proposed SCM 689.0
Bottom Sand Filter System Elevation 685.0
24" Buffer Requirement Elevation 683.0
Based on our observations it was determined that the seasonal high
groundwater elevation at the proposed sand filter location is deeper than
683.0.
The seasonal highwater elevation supports the use of a sand filter at this
location and elevation.
45 Spring Street, SW P.O. Box 268 Concord, NC 28026-0268 704-786-5404
www.cesicgs.com NC License No. C-0263

We appreciate the opportunity to be of service to you and we look forward to helping you
through project completion. If you have any questions, please feel free to call.
Respectfully submitted,
.\
\`‘�N CA R p��.,,,
oFEsS/0 ( tiq'-
SE
AL 24
James G. (Jay) Eaves III, PE
Division Engineer
45 Spring Street, SW P.O. Box 268 Concord, NC 28026-0268 704-786-5404
www.cesicgs.com NC License No. C-0263