SWA000022__06 2020-09-21 Courtyards at Emerald Lake As-built Stormwater Report_20201001

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301 McCullough Dr. Suite 109
Charlotte, NC 28262
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Stormwater Management Report
Courtyards at Emerald Lake
Epcon Communities
September 21, 2020

1.0 INTRODUCTION
The Project is a proposed 35.3 acre single family residential subdivision with 93 lots, associated
roadways and one clubhouse and pool. The site is undeveloped and is largely wooded. The site
has a few defined drainage draws all conveying stormwater to the existing un-named stream along
the southern property line and Lawyers Road. The site generally slopes 2% to 5% towards the un-
named stream.
The proposed development will be divided into two distinct watersheds. The majority of the
watershed will be collected by storm sewers and conveyed to a wet pond BMP located at the
northeast portion of the site. The southern portion of Avalon Place roadway and lot areas will have
the stormwater runoff collected by storm sewers and conveyed to a wet pond BMP.
There is 7.65 acres of off -site drainage area to the west that drains toward the southwest corner
of the property and to the un-named stream. Currently, only a portion of this offsite drainage area
flows across the project property. The post development grading will install a drainage swale along
the west property line to effectively direct the stormwater to the un-named stream without entering
the project site. Therefore, this offsite drainage area is shown on our drainage mapping, but not
included in the stormwater calculations.
The 0.32 acre offsite drainage area along the west property line will be collected and conveyed
to the wet pond BMP. The offsite area drainage will be included in the stormwater calculations.
The existing 0.36 acre and 0.63 acre drainage area to the northwest current drain from the project
site to the adjacent properties. These areas will be reduced in areas that drain offsite and will
remain largely undeveloped. The reduced areas will be included in the developed areas draining
to the wet pond BMP; while the smaller, undeveloped areas will continue to drain offsite as they
have and will have reduced stormwater runoff peak flows from the reduced areas.
The 0.73 acre offsite drainage area located near the northeast portion of the site currently drains
onto the project site and will continue to drain into the project and will be collected by storm sewers
and conveyed to the wet pond. No change in to the existing characteristics of the 0.73 acre area
is proposed.
The two on -site watersheds will have portions of the drainage areas that will be collected and
conveyed to the proposed stormwater BMPs and will have portions of the drainage areas that will
be left undeveloped and continue to direct discharge to the un-named stream. Each of the proposed
watersheds area analyzed separately and provides water quality for the developed portions of
the site and provides for a balanced overall stormwater control for the combined controlled and
directly discharged portions of the developed project. See the Pre and Post Tributary Area Maps
for reference.
2.0 EXISTING HYDROLOGY
The existing conditions hydrology exhibited on the Pre -Development Tributary Plan within the
construction plan set. The majority of the site is wooded in good hydrologic condition and is
predominantly Secrest — Cid Complex (ScA), Type C soils. Smaller portions of the project site have

Badin Channery Silt Loam, 2 to 8% slopes, Type B and Tarrus Gravelly Silt Loam, 2 to 8% slopes,
Type B soils. Type C soils was used for calculations to be conservative. The time of concentration
was calculated for each watershed and a minimum 7.5 minutes was used for the calculations, see
the HydroCAD output in Appendix B.
Rainfall Depths
Storm Event
Rainfall Depth
Rainfall Distribution
WQ
1.00
6-hr Type II
1-yr CPv
2.58
24-hr Type II
2 - year
2.28
6-hr Type II
10-year
3.72
6-hr Type II
25-year
1 4.38
6-hr Type II
50-year
4.92
6-hr Type II
3.0 PROPOSED CONDITIONS
The proposed site consists of single family, 1 /4 acre lots, an amenity area, associated roadways
and the two stormwater BMP structures. The rooftops, driveways, parking lots and onsite lawn areas
drain to storm inlets and yard catch basins that collects and conveys the runoff to the stormwater
management structures. The on -site stormwater runoff is routed through the BMP basins structures to
provide the required water quality BMP as well as Channel Protection Volume (CPv) control. The
less frequent storm event runoff flows are routed through the BMP structures without topping the
structures. BMP water quality calculations are included in Appendix A. The stormwater routing
output from the HydroCAD models are included in Appendix B. Some key elements of the
calculations are as follows:
The Channel Protection Volume (CPv) and peak release rates and elevations are calculated
for the pre -development and post development 1 yr, 24 hr Type II storm events. The storm
event volume difference is the CPv volume. The CPv and WQv volumes are added together
to determine the control volume and peak elevation in the BMPs to provide the appropriate
WQv and CPv control.
2. The 2 through 50 year, 6 hr Type II storm occurrence stormwater runoff release rates are
routed through the Wet Pond basins without topping the basins.
3. Actual percent of pervious and impervious areas were calculated for each RG watershed.
4. The travel paths for the stormwater runoff were also calculated; the minimum Time of
Concentration (Tc) was 7.5 minutes for all subareas.
4.0 WEST WET BASIN DESIGN
The northern 4.19 acres of proposed development stormwater runoff is collected by storm sewers
and conveyed to a wet basin system to the west. See Appendix A for Wet Pond calculations.

The Wet Basin will provide the Channel Protection Volume (CPv) as well as control the peak
release rates for the 2 year through 50 year storm event stormwater runoff to those of the pre -
development peak release rates. The CPv for this area is calculated as the difference of the post
development 1 year event hydrograph runoff volume and the pre -development 1 year event
hydrograph volume. The CPv is to be released over 48 hours.
WQv/CPv = Post Vol (27,453cf) - Pre Vol (15,045 cf) = 12,408 cf of volume to control the
release over 48 hours; the maximum diameter outlet orifice = 1.0 inches.
The Wet Basin normal water elevation is 639.28; the top of basin elevation is 643.50. The
maximum storage volume available is 68,819 cf. The basin will route the WQv, CPv and the 2
year through 50 year storm event runoffs without topping the basin crest.
The outlet control is a two (2) stage structure. The primary control is provided by one (1) 1.00 inch
orifice with invert set at 639.28 feet. The volume provided for the water quality/ CPv is from the
wet pond normal pool elevation (639.28) to the crest of the secondary outlet control. The
secondary outlet control is provided by one 24.0 inch wide by 9.0 inch high slot weirs with crests
set at 639.39 located on the face of the concrete control structure box. A 10 feet long emergency
weir is included along the top of the detention basin; the crest of the emergency weir is set at
642.71. The top of the wet pond is 639.28.
West Wet Pond Water Quality & CPv Summary Table
Event
Peak Inflow (cfs)
Peak Discharge
cfs
Peak HWL (ft)
Peak Storage
cu-ft
WQ (HydoCAD)
1 1.51
9:0-2 0.03
638.27 640.41
7-,6-79 12,423
West Wet Pond Routing Calculation Table
Event
Post-Dev
Inflow (cfs)
Post Dev
Routed Peak
(cfs)
Basin Peak
HWL (ft)
Basin Peak
Storage (cu-ft)
1
9.13
0.35
638.69
12,561
2
9.17
0.49
638.72
12,989
10
17.61
4.16
639.29
20,214
25
24.38
5.88
639.60
24,588
50
28.40
6.95
639.85
28,538
West Wet
Pond Routing As -Built Table
Event
Post-Dev
Inflow (cfs)
Post Dev Routed
Peak (cfs)
Basin Peak
HWL (ft)
Basin Peak
Storage (cu-ft)
1
9.13
0.27
640.50
13,524
2
9.17
0.36
640.53
13,870
10
17.61
3.69
641.08
21,017
25
27.38
5.53
641.37
25,204
50
28.40
6.63
641.61
29,143

West Watershed Combined Hydrograph Summary Table
Combined Summary Table
As -Built
Event
Pre-Dev
Peak Flow
(cfs)
Post-Dev
Inflow (cfs)
Post-Dev
Inflow (cfs)
1
4.16
1.39
1.36
2
3.65
1.36
1.33
10
13.20
8.05
8.47
25
20.04
12.47
12.54
50
25.19
15.67
15.46
5.0 EAST WET BASIN DESIGN
The eastern 22.5 acres of proposed development stormwater runoff is collected by storm sewers
and conveyed to a wet basin system located at the project eastern entry. The basin is comprised
of two basins connected by a culvert that equalizes the basin stormwater peak elevations. The
two compartment volumes are added together for routing calculations. See Appendix A for Wet
Pond calculations.
WQv/CPv = Post Vol (90,919cf) — Pre Vol (40,258cf) = 50,661 cf of volume to control the
release over 48 hours; the maximum diameter outlet orifice = 2.00 inches.
The Wet Basin normal water elevation is 634.50; the top of basin elevation is 640.00. The
maximum storage volume available is 164,773 cf. The basin will route the WQv, CPv and the 2
year through 50 year storm event runoffs without topping the basin crest.
The outlet control is a two (2) stage structure. The primary control is provided by one (1) 2.00 inch
orifice with invert set at 634.50 feet. The volume provided for the water quality/ CPv is from the
wet pond normal pool elevation (634.50) to the crest of the secondary outlet control. The
secondary outlet control is provided by four (4) 24.0 inch wide by 9.0 inch high slot weirs with
crests set at 637.51 located on the face of the concrete control structure box. A 10 feet long
emergency weir is included along the top of the detention basin; the crest of the emergency weir
is set at 639.10. The top of the wet pond is 640.00.
Wet Pond Water Quality & CPv Summary Table
Event
Peak Inflow (cfs)
Peak Discharge
(cfs)
Peak HWL (ft)
Peak Storage
(cu-ft)
WQ HydoCAD
-2-.� 2.61
GA-2 0.14
635.86 636.40
4 50,708

Wet Pond
Routing Calculation Table
Event
Post-Dev
Inflow (cfs)
Post Dev
Routed Peak
(cfs)
Basin Peak
HWL (ft)
Basin Peak
Storage (cu-ft)
1
10.65
0.15
636.60
51,298
2
10.83
0.14
636.28
42,789
10
28.80
4.12
637.97
91,570
25
1 39.33
1 10.81
1 638.23
1 100,109
50
1 47.57
1 17.88
1 638.46
1 107,568
Wet Pond Routing As -Built Table
Event
Post-Dev
Inflow (cfs)
Post Dev
Routed Peak
(cfs)
Basin Peak
HWL (ft)
Basin Peak
Storage (cu-ft)
1
16.78
0.17
637.28
77,639
2
17.82
0.16
636.93
66,850
10
38.63
10.82
638.07
103,466
25
50.34
16.21
638.44
116,377
50
59.12
16.80
638.98
135,575
East Watershed Combined Hydrograph Summary Table
Combined Summary Table
As -Built
Event
Pre-Dev Peak
Flow (cfs)
Post-Dev
Inflow (cfs)
Post-Dev
Inflow (cfs)
1
4.64
2.45
2.44
2
4.93
1.97
1.92
10
17.82
6.89
11.45
25
1 25.54
1 10.79
17.23
50
1 32.21
1 13.52
17.98

APPENDIX A:
Bio-Retention Sizing Calculations

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APPENDIX B:
Wet Pond Calculations

Courtyards of Enn-ld Lake
7/10/2020
Stormwater Management Calculations
Wet Pond Design
Notes
Predeveloped Calculations
Wet Basin
Untreated
Discharge
Total A- (ac)
18.85
0
18.85 ecrestael
Existing Woods HSG C(RCN-70)
18.85
Existing Pond HSG B (RCN-98)
0.00
0.00
Open Gass/ Weeds HSG B (RCN-61)
0.00
Open Space Type C(RCN-74)
0.00
Existing Impervious Area
0.00
0.00 s of impervious area ez condition
Composite RCN
70
70
RCN based on ezisting conditions
Tc(on.)
57
0
1-year Peak(cfs)
3.90
0.00
10-year Peak(cfs)
14.96
0
Post Developed Subareas
Subarea
Untreated
Wet Basin
Discharge
A-(ac)
18.85
0.00
18.85 ecrestael
Imp
46%
100%
RCN
85
98
Tc
39.1
0
1-year Peak(cfs)
16.78
0.00
and-ined peak
10-year Peak(cfs)
38.63
0.00
and-i..d peak
Allowable Release Rate
Total Area within Pre Subarea
18.85
Existing Woods Type B (RCN-55)
Existing Woods Type C(RCN-70)
18.85
Open Gass/ Weeds HSG B (RCN-61)
0
Open Space Type C(RCN-74)
0
Existing Impervious Area
0
Composite RCN
70
Applied Existing Impervious Area
0.00
Modified RCN
70
Tc(on.)
57
Total1 year Peak(cfs)
3.90
Total 10-year Peak(cfs)
14.96
Pro-ated l-y-Allowable(cfs)
3.90
Pro-ated 10-y-Allowable(cfs)
14.96
Water Quality Calculations
Existing Impervious Area Treated
0.00
0.00 ezisting impervious area treated
Impemo-Area not Treated
0.00
0.00
0.00 prop imp...- not treated for WQ
Imp
46
Rv
0.460
WQv(ac-ft)
0.72
18.85 ac developed
WQv(cu-ft)
31472
75%WQv(cu-ft)
23604
WQv Provided
31837
-
see Hydrocad Output
Water Quality Storage Pipe Design
Lowest Top of Casting (n)
Invert (ft)
Size(i )
Len gth(ft)
Top of Pipe Elevation (ft)
Water Quality Elevation(ft)
635.74
static water quality elevation
Invert Storm Filter Out (ft)
=
Overflow Weir Elevation (ft)
Min. Overflow Weir Width (ft)
1-year Peak Elevation (ft)
10-year Peak Elevation (ft)
Detention Pipe Design
Invert/Normal Pool(ft)
ize (in)
ength (ft)
Top of Pipe/Bank Elevation (ft)
Avaibble Stooge (cu-ft)
Lit Stage Outlet:
2nd Stage Outlet:
Tailwater Control Orffice (in)
Inlet Pipe Sae
Outlet Pipe Size
1-year Peak Elevation (ft)
10-year Peak Elevation (ft)
Wet/Dry/Sand Filters face Storage Design
wet basin
Top S. nd/Normal Pool(ft)
634.50
Top of Bank(t)
640.00
Lit Stage Outlet:
20" orifice @
634.50
2nd Stage Outlet
(4)24 wide
rs @ 637.51
3rd Stage Outlet:
10' wide Tap
air @ 639.10
Tailwater Control Orffice(in)
15"storm@
630.09
Emergency Spillway Elevation (ft)
639.10
Emergency Spillway W idth (ft)
10.00
1-ye, r Peak Elevatio n(ft)
637.28
10-year Peak Elevatio n (ft)
638.07
50-year Peak Elevation(ft)
638.98
Resu/ts
1-year Peak Release(cfs)
a
0.00
1-year Allowable(cfs)
W na
0.00
10-year Peak Release(cfs)
na
0
10-yearAllowable(cfs)
na
0.00
Total Stoage(cu-ft)
na
0
10-yea r Stooge Used(cu -ft)
na
0
Water Quofity Calculadons in the Goose watershed
east wq- post l-year vol=
90919
pre 1-year vol=
40258
dill-
50661
west wq- post l-year vol=
27453
pre 1-year vol=
15045
dill-
12408
W Q @ 636.40
W Q @ 640.41

APPENDIX C:
HydroCAD Output

S
E -A
Pre. East WS Pre. East WS to BMP
E2 4P
East Post Prop Retention Pond 6P 5P 11 P 15P
East
OE3 East Post Comb Prop Retention Pond Retention Pond East Retention Pond East
East WQv of 50661 @ below NP below NP- without
636.40 sedimentvolume
East Onsite Bypass
W1 W1-A W3
Pre. West WS Pre. West WS West Ons to Bypass
(i�
v1 P 3P
West Post West Basin West Out
2P 10P 17
West Basin WQv of West -Total Below West -Total Below
12408 @ 640.41 Normal Pool Normal Pool -without
sedimentvolume
Subcat Reach on Link n
Diagram for 20131483-RG1-Det-comb as -built 2020-06-24
Prepared by Symanetc, Printed 7/10/2020
D®10.10-3a s/n 03828 ©2020 HydroCAD Software Solutions LLC

20131483-RG1-Det-comb as -built 2020-06-24
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 2
Rainfall Events Listing
Event# Event Storm Type Curve Mode Duration B/B Depth AMC
Name (hours) (inches)
1 1 yr
Type II 24-hr
Default
24.00
1
2.58 2
2 2-yr
Charlotte 6-hr
2-yr
Default
6.00
1
2.28 2
3 10-yr
Charlotte 6-hr
10-yr
Default
6.00
1
3.72 2
4 25-yr
Charlotte 6-hr
2-yr
Default
6.00
1
4.38 2
5 50 yr
Charlotte 6-hr
2-yr
Default
6.00
1
4.92 2
6 WQ
Charlotte 6-hr
2-yr
Default
6.00
1
1.00 2

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 3S: West Post
Runoff = 9.13 cfs @ 11.99 hrs, Volume= 19,921 cf, Depth= 1.31"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
2.092 98 Paved parking, HSG C
2.100 74 >75% Grass cover, Good, HSG C
4.192 86 Weighted Average
2.100 50.10% Pervious Area
2.092 49.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Min Tc
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment E1: Pre. East WS
Runoff = 4.64 cfs @ 12.70 hrs, Volume= 40,258 cf, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
22.450 70 Woods, Good, HSG C
22.450 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 5
Summary for Subcatchment El -A: Pre. East WS to BM
Runoff = 3.89 cfs @ 12.70 hrs, Volume= 33,802 cf, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
18.850 70 Woods, Good, HSG C
18.850 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 6
Summary for Subcatchment E2: East Post
Runoff = 16.78 cfs @ 12.36 hrs, Volume= 85,019 cf, Depth= 1.24"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.530
98
NP of ponds
17.270
85
Residential, 45.5% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
85
Weighted Average
10.280
54.53% Pervious Area
8.570
45.47% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
32.3
164
0.0200
0.08
Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
6.8
1,511
0.0050
3.72
4.57 Pipe Channel, Storm Sewer
15.00" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
1
1
1
1
1
1
1
„ 1
N
1
3
0
LL
Subcatchment E2: East Post
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 7
Summary for Subcatchment E3: East Onsite Bypass
Runoff = 2.40 cfs @ 12.01 hrs, Volume= 5,900 cf, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
3.290 70 Woods, Good, HSG C
3.290 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Direct Discharge
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 8
Summary for Subcatchment W1: Pre. West WS
Runoff = 4.16 cfs @ 12.12 hrs, Volume= 15,045 cf, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
8.390 70 Woods, Good, HSG C
8.390 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
■ Runoff
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U
3
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LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 9
Summary for Subcatchment W1-A: Pre. West WS
Runoff = 2.08 cfs @ 12.12 hrs, Volume= 7,514 cf, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
4.190 70 Woods, Good, HSG C
4.190 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 10
Summary for Subcatchment W3: West Onsite Bypass
Runoff = 1.33 cfs @ 12.32 hrs, Volume= 7,532 cf, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 1 yr Rainfall=2.58"
Area (ac) CN Description
4.200 70 Woods, Good, HSG C
4.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
31.5 264 0.0550 0.14 Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 11
Summary for Pond 1 P: West Basin
Inflow Area = 182,604 sf, 49.90% Impervious, Inflow Depth = 1.31" for 1 yr event
Inflow = 9.13 cfs @ 11.99 hrs, Volume= 19,921 cf
Outflow = 0.27 cfs @ 14.93 hrs, Volume= 15,178 cf, Atten= 97%, Lag= 176.2 min
Primary = 0.27 cfs @ 14.93 hrs, Volume= 15,178 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 640.50' @ 14.93 hrs Surf.Area= 12,422 sf Storage= 13,524 cf
Plug -Flow detention time= 1,881.8 min calculated for 15,172 cf (76% of inflow)
Center -of -Mass det. time= 1,790.6 min ( 2,621.1 - 830.5 )
Volume Invert Avail.Storage Storage Description
#1 639.28' 68,819 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
639.28 9,519 0 0
640.00 11,439 7,545 7,545
641.00 13,400 12,420 19,964
642.00 18,522 15,961 35,925
643.00 23,054 20,788 56,713
643.50 25,369 12,106 68,819
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.32' S= 0.0068 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 640.39' 24.00" W x 9.00" H Vert. Orifice/Grate C= 0.600
Limited to weir flow at low heads
#4 Secondary 642.70' 10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.27 cfs @ 14.93 hrs HW=640.50' (Free Discharge)
L1=Culvert (Passes 0.27 cfs of 25.77 cfs potential flow)
�__3=Orifi
2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.23 fps)
ce/Grate (Orifice Controls 0.24 cfs @ 1.07 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=639.28' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 12
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 13
Summary for Pond 2P: West Basin WQv of 12408 @ 640.41
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 640.41' Surf.Area= 12,243 sf Storage= 12,423 cf
Peak Elev= 640.41' @ 0.00 hrs Surf.Area= 12,243 sf Storage= 12,423 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 639.28'
UMMI1
Description
68,842 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
639.28
9,583
0
0
640.00
11,439
7,568
7,568
641.00
13,400
12,420
19,987
642.00
18,522
15,961
35,948
643.00
23,054
20,788
56,736
643.50
25,369
12,106
68,842
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.50' S= 0.0024 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.03 cfs @ 0.00 hrs HW=640.41' (Free Discharge)
L1=Culvert (Passes 0.03 cfs of 24.58 cfs potential flow)
L2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.02 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 14
Pond 2P: West Basin WQv of 12408 @ 640.41
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 15
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 0.75" for 1 yr event
Inflow = 1.36 cfs @ 12.32 hrs, Volume= 22,710 cf
Primary = 1.36 cfs @ 12.32 hrs, Volume= 22,710 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary
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LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 16
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
45.47% Impervious,
Inflow Depth = 1.24" for 1 yr event
Inflow =
16.78 cfs @
12.36 hrs, Volume=
85,019 cf
Outflow =
0.17 cfs @
24.62 hrs, Volume=
55,741 cf, Atten= 99%, Lag= 735.5 min
Primary =
0.17 cfs @
24.62 hrs, Volume=
55,741 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 637.28' @ 24.62 hrs Surf.Area= 31,798 sf Storage= 77,639 cf
Plug -Flow detention time= 2,979.9 min calculated for 55,718 cf (66% of inflow)
Center -of -Mass det. time= 2,869.5 min ( 3,733.1 - 863.6 )
Volume
Invert Avail.Storage Storage
Description
#1
634.50' 121,989 cf BMP 1
(Prismatic) Listed below (Recalc)
#2
634.50'
42,682 cf BMP 2
(Prismatic) Listed below (Recalc)
164,671 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
18,335
0
0
635.00
19,462
9,449
9,449
636.00
21,232
20,347
29,796
637.00
22,977
22,105
51,901
638.00
24,759
23,868
75,769
639.00
26,568
25,664
101,432
639.75
28,251
20,557
121,989
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
4,923
0
0
635.00
6,006
2,732
2,732
636.00
7,194
6,600
9,332
637.00
8,067
7,631
16,963
638.00
8,986
8,527
25,489
639.00
9,950
9,468
34,957
639.75
10,648
7,724
42,682
Device Routina Invert Outlet Devices
#1
Primary
630.09'
15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2
Device 1
634.50'
2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
#3
Device 1
637.51'
24.00" W x 9.00" H Vert. Windows X 4.00 C= 0.600
Limited to weir flow at low heads
#4
Secondary
639.10'
10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 17
Primary OutFlow Max=0.17 cfs @ 24.62 hrs HW=637.28' (Free Discharge)
L1=Culvert (Passes 0.17 cfs of 14.84 cfs potential flow)
�2=WQ
Orifice (Orifice Controls 0.17 cfs @ 7.91 fps)
3=Windows ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)
N
U
3
0
LL
Pond 4P: Prop Retention Pond East
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
E Inflow
M outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 18
Summary for Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 636.40' Surf.Area= 29,473 sf Storage= 50,708 cf
Peak Elev= 636.40' @ 0.00 hrs Surf.Area= 29,473 sf Storage= 50,708 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 634.50'
UMMI1
Description
164,773 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
23,258
0
0
635.00
25,467
12,181
12,181
636.00
28,426
26,947
39,128
637.00
31,044
29,735
68,863
638.00
33,745
32,395
101,257
639.00
36,635
35,190
136,447
639.75
38,899
28,325
164,773
Device Routing Invert Outlet Devices
#1 Primary 630.09' 15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 634.50' 2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.14 cfs @ 0.00 hrs HW=636.40' (Free Discharge)
L1=Culvert (Passes 0.14 cfs of 13.72 cfs potential flow)
L2=WQ Orifice (Orifice Controls 0.14 cfs @ 6.49 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 19
Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 20
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 38.71 % Impervious, Inflow Depth > 0.77" for 1 yr event
Inflow = 2.44 cfs @ 12.01 hrs, Volume= 61,641 cf
Primary = 2.44 cfs @ 12.01 hrs, Volume= 61,641 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary
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LL

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 21
Summary for Pond 10P: West -Total Below Normal Pool
Volume
Invert Avail.Storage Storage
Description
#1
634.00'
9,245 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.00'
20,162 cf Main
perm pool (Prismatic) Listed below (Recalc)
29,407 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
326
0
0
635.00
1,193
760
760
636.00
1,482
1,338
2,097
637.00
1,827
1,655
3,752
638.00
2,248
2,038
5,789
639.00
2,936
2,592
8,381
639.28
3,233
864
9,245
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
2,103
0
0
635.00
2,686
2,395
2,395
636.00
3,284
2,985
5,380
637.00
3,929
3,607
8,986
638.00
4,617
4,273
13,259
639.00
5,790
5,204
18,463
639.28
6,350
1,700
20,162

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 22
Summary for Pond 11 P: Retention Pond East below NP
Volume Invert Avail.Storaae Storaae Description
#1
626.48'
6,940 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
626.48'
65,866 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
628.00'
15,630 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
88,437 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
29
0 0
627.00
69
25 25
628.00
187
128 153
629.00
359
273 426
630.00
584
472 898
631.00
860
722 1,620
632.00
1,183
1,022 2,641
633.00
1,550
1,367 4,008
634.00
1,977
1,764 5,771
634.50
2,699
1,169 6,940
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
4,551
0 0
627.00
4,936
2,467 2,467
628.00
5,686
5,311 7,778
629.00
6,482
6,084 13,862
630.00
7,302
6,892 20,754
631.00
8,159
7,731 28,484
632.00
9,057
8,608 37,092
633.00
10,016
9,537 46,629
634.00
13,761
11,889 58,517
634.50
15,636
7,349 65,866
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
628.00
762
0 0
629.00
1,164
963 963
630.00
1,624
1,394 2,357
631.00
2,141
1,883 4,240
632.00
2,715
2,428 6,668
633.00
3,347
3,031 9,699
634.00
4,036
3,692 13,390
634.50
4,923
2,240 15,630

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 23
Summary for Pond 15P: Retention Pond East below NP - without sediment volume
Volume Invert Avail.Storaae Storaae Description
#1
627.48'
6,867 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
627.48'
60,943 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
629.00'
14,667 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
82,477 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
122
0 0
628.00
187
80 80
629.00
359
273 353
630.00
584
472 825
631.00
860
722 1,547
632.00
1,183
1,022 2,568
633.00
1,550
1,367 3,935
634.00
1,977
1,764 5,698
634.50
2,699
1,169 6,867
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
5,293
0 0
628.00
5,686
2,855 2,855
629.00
6,482
6,084 8,939
630.00
7,302
6,892 15,831
631.00
8,159
7,731 23,561
632.00
9,057
8,608 32,169
633.00
10,016
9,537 41,706
634.00
13,761
11,889 53,594
634.50
15,636
7,349 60,943
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
629.00
1,164
0 0
630.00
1,624
1,394 1,394
631.00
2,141
1,883 3,277
632.00
2,715
2,428 5,705
633.00
3,347
3,031 8,736
634.00
4,036
3,692 12,427
634.50
4,923
2,240 14,667

20131483-RG1-Det-comb as -built 2020-06-24 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 24
Summary for Pond 17P: West -Total Below Normal Pool -without sediment volume
Volume
Invert Avail.Storage Storage
Description
#1
634.50'
9,048 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.50'
19,040 cf Main
perm pool (Prismatic) Listed below (Recalc)
28,088 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
1,057
0
0
635.00
1,193
563
563
636.00
1,482
1,338
1,900
637.00
1,827
1,655
3,555
638.00
2,248
2,038
5,592
639.00
2,936
2,592
8,184
639.28
3,233
864
9,048
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
2,404
0
0
635.00
2,686
1,273
1,273
636.00
3,284
2,985
4,258
637.00
3,929
3,607
7,864
638.00
4,617
4,273
12,137
639.00
5,790
5,204
17,341
639.28
6,350
1,700
19,040

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 25
Summary for Subcatchment 3S: West Post
Runoff = 9.17 cfs @ 3.19 hrs, Volume= 16,225 cf, Depth= 1.07"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
2.092 98 Paved parking, HSG C
2.100 74 >75% Grass cover, Good, HSG C
4.192 86 Weighted Average
2.100 50.10% Pervious Area
2.092 49.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Min Tc
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 26
Summary for Subcatchment E1: Pre. East WS
Runoff = 4.93 cfs @ 4.01 hrs, Volume= 28,901 cf, Depth= 0.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
22.450 70 Woods, Good, HSG C
22.450 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
U
3
0
LL
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 160 165 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 27
Summary for Subcatchment El -A: Pre. East WS to BM
Runoff = 4.14 cfs @ 4.01 hrs, Volume= 24,267 cf, Depth= 0.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
18.850 70 Woods, Good, HSG C
18.850 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
U
3
0
LL
0 ____ ___
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 160 105 110 115 120
Time (hours)
❑ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 28
Summary for Subcatchment E2: East Post
Runoff = 17.82 cfs @ 3.62 hrs, Volume= 68,829 cf, Depth= 1.01"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.530
98
NP of ponds
17.270
85
Residential, 45.5% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
85
Weighted Average
10.280
54.53% Pervious Area
8.570
45.47% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
32.3
164
0.0200
0.08
Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
6.8
1,511
0.0050
3.72
4.57 Pipe Channel, Storm Sewer
15.00" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
1
1
1
1
1
1
1
1
w 1
U
3 1
0
LL
Subcatchment E2: East Post
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 29
Summary for Subcatchment E3: East Onsite Bypass
Runoff = 1.91 cfs @ 3.23 hrs, Volume= 4,235 cf, Depth= 0.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
3.290 70 Woods, Good, HSG C
3.290 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Direct Discharge
N
U
3
0
LL
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
❑ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 30
Summary for Subcatchment W1: Pre. West WS
Runoff = 3.65 cfs @ 3.37 hrs, Volume= 10,801 cf, Depth= 0.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
8.390 70 Woods, Good, HSG C
8.390 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 31
Summary for Subcatchment W1-A: Pre. West WS
Runoff = 1.82 cfs @ 3.37 hrs, Volume= 5,394 cf, Depth= 0.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
4.190 70 Woods, Good, HSG C
4.190 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
Subcatchment W1-A: Pre. West WS
Hydrograph
E
N
U
3 1
0
LL
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
❑ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 32
Summary for Subcatchment W3: West Onsite Bypass
Runoff = 1.31 cfs @ 3.61 hrs, Volume= 5,407 cf, Depth= 0.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
4.200 70 Woods, Good, HSG C
4.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
31.5 264 0.0550 0.14 Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 33
Summary for Pond 1 P: West Basin
Inflow Area = 182,604 sf, 49.90% Impervious, Inflow Depth = 1.07" for 2-yr event
Inflow = 9.17 cfs @ 3.19 hrs, Volume= 16,225 cf
Outflow = 0.36 cfs @ 5.31 hrs, Volume= 12,446 cf, Atten= 96%, Lag= 127.1 min
Primary = 0.36 cfs @ 5.31 hrs, Volume= 12,446 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 640.53' @ 5.31 hrs Surf.Area= 12,476 sf Storage= 13,870 cf
Plug -Flow detention time= 2,360.6 min calculated for 12,446 cf (77% of inflow)
Center -of -Mass det. time= 2,339.3 min ( 2,557.6 - 218.2 )
Volume Invert Avail.Storage Storage Description
#1 639.28' 68,819 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
639.28 9,519 0 0
640.00 11,439 7,545 7,545
641.00 13,400 12,420 19,964
642.00 18,522 15,961 35,925
643.00 23,054 20,788 56,713
643.50 25,369 12,106 68,819
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.32' S= 0.0068 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 640.39' 24.00" W x 9.00" H Vert. Orifice/Grate C= 0.600
Limited to weir flow at low heads
#4 Secondary 642.70' 10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.36 cfs @ 5.31 hrs HW=640.53' (Free Discharge)
L1=Culvert (Passes 0.36 cfs of 25.89 cfs potential flow)
�__3=Orifi
2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.29 fps)
ce/Grate (Orifice Controls 0.33 cfs @ 1.20 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=639.28' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 34
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 35
Summary for Pond 2P: West Basin WQv of 12408 @ 640.41
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 640.41' Surf.Area= 12,243 sf Storage= 12,423 cf
Peak Elev= 640.41' @ 0.00 hrs Surf.Area= 12,243 sf Storage= 12,423 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 639.28'
UMMI1
Description
68,842 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
639.28
9,583
0
0
640.00
11,439
7,568
7,568
641.00
13,400
12,420
19,987
642.00
18,522
15,961
35,948
643.00
23,054
20,788
56,736
643.50
25,369
12,106
68,842
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.50' S= 0.0024 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.03 cfs @ 0.00 hrs HW=640.41' (Free Discharge)
L1=Culvert (Passes 0.03 cfs of 24.58 cfs potential flow)
L2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.02 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 36
N
U
Pond 2P: West Basin WQv of 12408 @ 640.41
Hydrograph
Time (hours)
❑ Inflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 37
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 0.59" for 2-yr event
Inflow = 1.33 cfs @ 3.61 hrs, Volume= 17,853 cf
Primary = 1.33 cfs @ 3.61 hrs, Volume= 17,853 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
N
U
3
0
LL
Pond 3P: West Out
Hydrograph
1
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
I nflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 38
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
45.47% Impervious,
Inflow Depth = 1.01" for 2-yr event
Inflow =
17.82 cfs @
3.62 hrs, Volume=
68,829 cf
Outflow =
0.16 cfs @
6.94 hrs, Volume=
51,768 cf, Atten= 99%, Lag= 199.1 min
Primary =
0.16 cfs @
6.94 hrs, Volume=
51,768 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 636.93' @ 6.94 hrs Surf.Area= 30,874 sf Storage= 66,850 cf
Plug -Flow detention time= 3,105.1 min calculated for 51,746 cf (75% of inflow)
Center -of -Mass det. time= 3,083.4 min ( 3,332.0 - 248.6 )
Volume
Invert Avail.Storage Storage
Description
#1
634.50' 121,989 cf BMP 1
(Prismatic) Listed below (Recalc)
#2
634.50'
42,682 cf BMP 2
(Prismatic) Listed below (Recalc)
164,671 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
18,335
0
0
635.00
19,462
9,449
9,449
636.00
21,232
20,347
29,796
637.00
22,977
22,105
51,901
638.00
24,759
23,868
75,769
639.00
26,568
25,664
101,432
639.75
28,251
20,557
121,989
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
4,923
0
0
635.00
6,006
2,732
2,732
636.00
7,194
6,600
9,332
637.00
8,067
7,631
16,963
638.00
8,986
8,527
25,489
639.00
9,950
9,468
34,957
639.75
10,648
7,724
42,682
Device Routina Invert Outlet Devices
#1
Primary
630.09'
15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2
Device 1
634.50'
2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
#3
Device 1
637.51'
24.00" W x 9.00" H Vert. Windows X 4.00 C= 0.600
Limited to weir flow at low heads
#4
Secondary
639.10'
10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 39
Primary OutFlow Max=0.16 cfs @ 6.94 hrs HW=636.93' (Free Discharge)
L1=Culvert (Passes 0.16 cfs of 14.41 cfs potential flow)
�2=WQ
Orifice (Orifice Controls 0.16 cfs @ 7.38 fps)
3=Windows ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)
N
U
3
0
LL
Pond 4P: Prop Retention Pond East
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
E Inflow
M outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 40
Summary for Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 636.40' Surf.Area= 29,473 sf Storage= 50,708 cf
Peak Elev= 636.40' @ 0.00 hrs Surf.Area= 29,473 sf Storage= 50,708 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 634.50'
UMMI1
Description
164,773 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
23,258
0
0
635.00
25,467
12,181
12,181
636.00
28,426
26,947
39,128
637.00
31,044
29,735
68,863
638.00
33,745
32,395
101,257
639.00
36,635
35,190
136,447
639.75
38,899
28,325
164,773
Device Routing Invert Outlet Devices
#1 Primary 630.09' 15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 634.50' 2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.14 cfs @ 0.00 hrs HW=636.40' (Free Discharge)
L1=Culvert (Passes 0.14 cfs of 13.72 cfs potential flow)
L2=WQ Orifice (Orifice Controls 0.14 cfs @ 6.49 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 41
Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 42
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 38.71 % Impervious, Inflow Depth > 0.70" for 2-yr event
Inflow = 1.92 cfs @ 3.23 hrs, Volume= 56,003 cf
Primary = 1.92 cfs @ 3.23 hrs, Volume= 56,003 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 43
Summary for Pond 10P: West -Total Below Normal Pool
Volume
Invert Avail.Storage Storage
Description
#1
634.00'
9,245 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.00'
20,162 cf Main
perm pool (Prismatic) Listed below (Recalc)
29,407 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
326
0
0
635.00
1,193
760
760
636.00
1,482
1,338
2,097
637.00
1,827
1,655
3,752
638.00
2,248
2,038
5,789
639.00
2,936
2,592
8,381
639.28
3,233
864
9,245
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
2,103
0
0
635.00
2,686
2,395
2,395
636.00
3,284
2,985
5,380
637.00
3,929
3,607
8,986
638.00
4,617
4,273
13,259
639.00
5,790
5,204
18,463
639.28
6,350
1,700
20,162

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 44
Summary for Pond 11 P: Retention Pond East below NP
Volume Invert Avail.Storaae Storaae Description
#1
626.48'
6,940 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
626.48'
65,866 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
628.00'
15,630 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
88,437 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
29
0 0
627.00
69
25 25
628.00
187
128 153
629.00
359
273 426
630.00
584
472 898
631.00
860
722 1,620
632.00
1,183
1,022 2,641
633.00
1,550
1,367 4,008
634.00
1,977
1,764 5,771
634.50
2,699
1,169 6,940
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
4,551
0 0
627.00
4,936
2,467 2,467
628.00
5,686
5,311 7,778
629.00
6,482
6,084 13,862
630.00
7,302
6,892 20,754
631.00
8,159
7,731 28,484
632.00
9,057
8,608 37,092
633.00
10,016
9,537 46,629
634.00
13,761
11,889 58,517
634.50
15,636
7,349 65,866
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
628.00
762
0 0
629.00
1,164
963 963
630.00
1,624
1,394 2,357
631.00
2,141
1,883 4,240
632.00
2,715
2,428 6,668
633.00
3,347
3,031 9,699
634.00
4,036
3,692 13,390
634.50
4,923
2,240 15,630

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 45
Summary for Pond 15P: Retention Pond East below NP - without sediment volume
Volume Invert Avail.Storaae Storaae Description
#1
627.48'
6,867 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
627.48'
60,943 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
629.00'
14,667 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
82,477 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
122
0 0
628.00
187
80 80
629.00
359
273 353
630.00
584
472 825
631.00
860
722 1,547
632.00
1,183
1,022 2,568
633.00
1,550
1,367 3,935
634.00
1,977
1,764 5,698
634.50
2,699
1,169 6,867
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
5,293
0 0
628.00
5,686
2,855 2,855
629.00
6,482
6,084 8,939
630.00
7,302
6,892 15,831
631.00
8,159
7,731 23,561
632.00
9,057
8,608 32,169
633.00
10,016
9,537 41,706
634.00
13,761
11,889 53,594
634.50
15,636
7,349 60,943
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
629.00
1,164
0 0
630.00
1,624
1,394 1,394
631.00
2,141
1,883 3,277
632.00
2,715
2,428 5,705
633.00
3,347
3,031 8,736
634.00
4,036
3,692 12,427
634.50
4,923
2,240 14,667

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 46
Summary for Pond 17P: West -Total Below Normal Pool -without sediment volume
Volume
Invert Avail.Storage Storage
Description
#1
634.50'
9,048 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.50'
19,040 cf Main
perm pool (Prismatic) Listed below (Recalc)
28,088 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
1,057
0
0
635.00
1,193
563
563
636.00
1,482
1,338
1,900
637.00
1,827
1,655
3,555
638.00
2,248
2,038
5,592
639.00
2,936
2,592
8,184
639.28
3,233
864
9,048
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
2,404
0
0
635.00
2,686
1,273
1,273
636.00
3,284
2,985
4,258
637.00
3,929
3,607
7,864
638.00
4,617
4,273
12,137
639.00
5,790
5,204
17,341
639.28
6,350
1,700
19,040

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 47
Summary for Subcatchment 3S: West Post
Runoff = 17.61 cfs @ 3.19 hrs, Volume= 34,910 cf, Depth= 2.29"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
2.092 98 Paved parking, HSG C
2.100 74 >75% Grass cover, Good, HSG C
4.192 86 Weighted Average
2.100 50.10% Pervious Area
2.092 49.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Min Tc
1
1
1
1
1
1
1
1
N 1
U
3 1
0
LL
Subcatchment 3S: West Post
Hydrograph
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 48
Summary for Subcatchment E1: Pre. East WS
Runoff = 17.81 cfs @ 3.92 hrs, Volume= 93,434 cf, Depth= 1.15"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
22.450 70 Woods, Good, HSG C
22.450 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
1
1
1
1
1
1
1
1
w 1
U
3 1
0
LL
Subcatchment E1: Pre. East WS
Hydrograph
V 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 49
Summary for Subcatchment El -A: Pre. East WS to BM
Runoff = 14.95 cfs @ 3.92 hrs, Volume= 78,451 cf, Depth= 1.15"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
18.850 70 Woods, Good, HSG C
18.850 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
1
1
1
N
U
3
0
LL
Subcatchment El -A: Pre. East WS to BMP
Hydrograph
V 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 50
Summary for Subcatchment E2: East Post
Runoff = 38.63 cfs @ 3.60 hrs, Volume= 151,165 cf, Depth= 2.21"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.530
98
NP of ponds
17.270
85
Residential, 45.5% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
85
Weighted Average
10.280
54.53% Pervious Area
8.570
45.47% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
32.3
164
0.0200
0.08
Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
6.8
1,511
0.0050
3.72
4.57 Pipe Channel, Storm Sewer
15.00" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
N
U
3
0
LL
Subcatchment E2: East Post
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 51
Summary for Subcatchment E3: East Onsite Bypass
Runoff = 6.80 cfs @ 3.20 hrs, Volume= 13,692 cf, Depth= 1.15"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
3.290 70 Woods, Good, HSG C
3.290 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Direct Discharge
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 52
Summary for Subcatchment W1: Pre. West WS
Runoff = 13.20 cfs @ 3.33 hrs, Volume= 34,918 cf, Depth= 1.15"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
8.390 70 Woods, Good, HSG C
8.390 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 53
Summary for Subcatchment W1-A: Pre. West WS
Runoff = 6.59 cfs @ 3.33 hrs, Volume= 17,438 cf, Depth= 1.15"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
4.190 70 Woods, Good, HSG C
4.190 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 54
Summary for Subcatchment W3: West Onsite Bypass
Runoff = 4.79 cfs @ 3.55 hrs, Volume= 17,480 cf, Depth= 1.15"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
4.200 70 Woods, Good, HSG C
4.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
31.5 264 0.0550 0.14 Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 55
Summary for Pond 1 P: West Basin
Inflow Area = 182,604 sf, 49.90% Impervious, Inflow Depth = 2.29" for 10-yr event
Inflow = 17.61 cfs @ 3.19 hrs, Volume= 34,910 cf
Outflow = 3.69 cfs @ 3.60 hrs, Volume= 31,095 cf, Atten= 79%, Lag= 24.6 min
Primary = 3.69 cfs @ 3.60 hrs, Volume= 31,095 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 641.08' @ 3.60 hrs Surf.Area= 13,796 sf Storage= 21,017 cf
Plug -Flow detention time= 981.6 min calculated for 31,082 cf (89% of inflow)
Center -of -Mass det. time= 971.5 min ( 1,183.9 - 212.4 )
Volume Invert Avail.Storage Storage Description
#1 639.28' 68,819 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
639.28 9,519 0 0
640.00 11,439 7,545 7,545
641.00 13,400 12,420 19,964
642.00 18,522 15,961 35,925
643.00 23,054 20,788 56,713
643.50 25,369 12,106 68,819
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.32' S= 0.0068 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 640.39' 24.00" W x 9.00" H Vert. Orifice/Grate C= 0.600
Limited to weir flow at low heads
#4 Secondary 642.70' 10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=3.69 cfs @ 3.60 hrs HW=641.08' (Free Discharge)
L1=Culvert (Passes 3.69 cfs of 28.21 cfs potential flow)
�__3=Orifi
2=Orifice/Grate (Orifice Controls 0.03 cfs @ 6.38 fps)
ce/Grate (Orifice Controls 3.66 cfs @ 2.66 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=639.28' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 56
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R oufflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 57
Summary for Pond 2P: West Basin WQv of 12408 @ 640.41
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 640.41' Surf.Area= 12,243 sf Storage= 12,423 cf
Peak Elev= 640.41' @ 0.00 hrs Surf.Area= 12,243 sf Storage= 12,423 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 639.28'
UMMI1
Description
68,842 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
639.28
9,583
0
0
640.00
11,439
7,568
7,568
641.00
13,400
12,420
19,987
642.00
18,522
15,961
35,948
643.00
23,054
20,788
56,736
643.50
25,369
12,106
68,842
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.50' S= 0.0024 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.03 cfs @ 0.00 hrs HW=640.41' (Free Discharge)
L1=Culvert (Passes 0.03 cfs of 24.58 cfs potential flow)
L2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.02 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 58
Pond 2P: West Basin WQv of 12408 @ 640.41
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 59
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 1.59" for 10-yr event
Inflow = 8.47 cfs @ 3.56 hrs, Volume= 48,574 cf
Primary = 8.47 cfs @ 3.56 hrs, Volume= 48,574 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
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3
0
LL
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Inflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 60
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
45.47% Impervious,
Inflow Depth = 2.21" for 10-yr event
Inflow =
38.63 cfs @
3.60 hrs, Volume=
151,165 cf
Outflow =
10.82 cfs @
4.42 hrs, Volume=
123,303 cf, Atten= 72%, Lag= 49.0 min
Primary =
10.82 cfs @
4.42 hrs, Volume=
123,303 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 638.07' @ 4.42 hrs Surf.Area= 33,926 sf Storage= 103,467 cf
Plug -Flow detention time= 1,616.1 min calculated for 123,303 cf (82% of inflow)
Center -of -Mass det. time= 1,597.6 min ( 1,840.1 - 242.5 )
Volume
Invert Avail.Storage Storage
Description
#1
634.50' 121,989 cf BMP 1
(Prismatic) Listed below (Recalc)
#2
634.50'
42,682 cf BMP 2
(Prismatic) Listed below (Recalc)
164,671 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
18,335
0
0
635.00
19,462
9,449
9,449
636.00
21,232
20,347
29,796
637.00
22,977
22,105
51,901
638.00
24,759
23,868
75,769
639.00
26,568
25,664
101,432
639.75
28,251
20,557
121,989
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
4,923
0
0
635.00
6,006
2,732
2,732
636.00
7,194
6,600
9,332
637.00
8,067
7,631
16,963
638.00
8,986
8,527
25,489
639.00
9,950
9,468
34,957
639.75
10,648
7,724
42,682
Device Routina Invert Outlet Devices
#1
Primary
630.09'
15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2
Device 1
634.50'
2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
#3
Device 1
637.51'
24.00" W x 9.00" H Vert. Windows X 4.00 C= 0.600
Limited to weir flow at low heads
#4
Secondary
639.10'
10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 61
Primary OutFlow Max=10.80 cfs @ 4.42 hrs HW=638.06' (Free Discharge)
L1=Culvert (Passes 10.80 cfs of 15.78 cfs potential flow)
�2=WQ
Orifice (Orifice Controls 0.20 cfs @ 8.98 fps)
3=Windows (Orifice Controls 10.61 cfs @ 2.39 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)
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3
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Pond 4P: Prop Retention Pond East
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
E Inflow
M outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 62
Summary for Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 636.40' Surf.Area= 29,473 sf Storage= 50,708 cf
Peak Elev= 636.40' @ 0.00 hrs Surf.Area= 29,473 sf Storage= 50,708 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 634.50'
UMMI1
Description
164,773 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
23,258
0
0
635.00
25,467
12,181
12,181
636.00
28,426
26,947
39,128
637.00
31,044
29,735
68,863
638.00
33,745
32,395
101,257
639.00
36,635
35,190
136,447
639.75
38,899
28,325
164,773
Device Routing Invert Outlet Devices
#1 Primary 630.09' 15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 634.50' 2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.14 cfs @ 0.00 hrs HW=636.40' (Free Discharge)
L1=Culvert (Passes 0.14 cfs of 13.72 cfs potential flow)
L2=WQ Orifice (Orifice Controls 0.14 cfs @ 6.49 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 63
Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 64
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 38.71 % Impervious, Inflow Depth > 1.70" for 10-yr event
Inflow = 11.45 cfs @ 4.41 hrs, Volume= 136,996 cf
Primary = 11.45 cfs @ 4.41 hrs, Volume= 136,996 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Pond 6P: East Post Comb
Hydrograph
N
U
3
0
LL
I 1 nflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 65
Summary for Pond 10P: West -Total Below Normal Pool
Volume
Invert Avail.Storage Storage
Description
#1
634.00'
9,245 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.00'
20,162 cf Main
perm pool (Prismatic) Listed below (Recalc)
29,407 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
326
0
0
635.00
1,193
760
760
636.00
1,482
1,338
2,097
637.00
1,827
1,655
3,752
638.00
2,248
2,038
5,789
639.00
2,936
2,592
8,381
639.28
3,233
864
9,245
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
2,103
0
0
635.00
2,686
2,395
2,395
636.00
3,284
2,985
5,380
637.00
3,929
3,607
8,986
638.00
4,617
4,273
13,259
639.00
5,790
5,204
18,463
639.28
6,350
1,700
20,162

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
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Summary for Pond 11 P: Retention Pond East below NP
Volume Invert Avail.Storaae Storaae Description
#1
626.48'
6,940 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
626.48'
65,866 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
628.00'
15,630 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
88,437 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
29
0 0
627.00
69
25 25
628.00
187
128 153
629.00
359
273 426
630.00
584
472 898
631.00
860
722 1,620
632.00
1,183
1,022 2,641
633.00
1,550
1,367 4,008
634.00
1,977
1,764 5,771
634.50
2,699
1,169 6,940
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
4,551
0 0
627.00
4,936
2,467 2,467
628.00
5,686
5,311 7,778
629.00
6,482
6,084 13,862
630.00
7,302
6,892 20,754
631.00
8,159
7,731 28,484
632.00
9,057
8,608 37,092
633.00
10,016
9,537 46,629
634.00
13,761
11,889 58,517
634.50
15,636
7,349 65,866
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
628.00
762
0 0
629.00
1,164
963 963
630.00
1,624
1,394 2,357
631.00
2,141
1,883 4,240
632.00
2,715
2,428 6,668
633.00
3,347
3,031 9,699
634.00
4,036
3,692 13,390
634.50
4,923
2,240 15,630

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 67
Summary for Pond 15P: Retention Pond East below NP - without sediment volume
Volume Invert Avail.Storaae Storaae Description
#1
627.48'
6,867 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
627.48'
60,943 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
629.00'
14,667 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
82,477 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
122
0 0
628.00
187
80 80
629.00
359
273 353
630.00
584
472 825
631.00
860
722 1,547
632.00
1,183
1,022 2,568
633.00
1,550
1,367 3,935
634.00
1,977
1,764 5,698
634.50
2,699
1,169 6,867
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
5,293
0 0
628.00
5,686
2,855 2,855
629.00
6,482
6,084 8,939
630.00
7,302
6,892 15,831
631.00
8,159
7,731 23,561
632.00
9,057
8,608 32,169
633.00
10,016
9,537 41,706
634.00
13,761
11,889 53,594
634.50
15,636
7,349 60,943
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
629.00
1,164
0 0
630.00
1,624
1,394 1,394
631.00
2,141
1,883 3,277
632.00
2,715
2,428 5,705
633.00
3,347
3,031 8,736
634.00
4,036
3,692 12,427
634.50
4,923
2,240 14,667

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 68
Summary for Pond 17P: West -Total Below Normal Pool -without sediment volume
Volume
Invert Avail.Storage Storage
Description
#1
634.50'
9,048 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.50'
19,040 cf Main
perm pool (Prismatic) Listed below (Recalc)
28,088 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
1,057
0
0
635.00
1,193
563
563
636.00
1,482
1,338
1,900
637.00
1,827
1,655
3,555
638.00
2,248
2,038
5,592
639.00
2,936
2,592
8,184
639.28
3,233
864
9,048
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
2,404
0
0
635.00
2,686
1,273
1,273
636.00
3,284
2,985
4,258
637.00
3,929
3,607
7,864
638.00
4,617
4,273
12,137
639.00
5,790
5,204
17,341
639.28
6,350
1,700
19,040

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 69
Summary for Subcatchment 3S: West Post
Runoff = 24.38 cfs @ 3.19 hrs, Volume= 44,021 cf, Depth= 2.89"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
2.092 98 Paved parking, HSG C
2.100 74 >75% Grass cover, Good, HSG C
4.192 86 Weighted Average
2.100 50.10% Pervious Area
2.092 49.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Min Tc
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 70
Summary for Subcatchment E1: Pre. East WS
Runoff = 25.51 cfs @ 3.89 hrs, Volume= 129,521 cf, Depth= 1.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
22.450 70 Woods, Good, HSG C
22.450 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
U
3
0
LL
0'
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
❑ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 71
Summary for Subcatchment El -A: Pre. East WS to BM
Runoff = 21.42 cfs @ 3.89 hrs, Volume= 108,752 cf, Depth= 1.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
18.850 70 Woods, Good, HSG C
18.850 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
U
3
0
LL
Subcatchment El -A: Pre. East WS to BMP
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 72
Summary for Subcatchment E2: East Post
Runoff = 50.34 cfs @ 3.60 hrs, Volume= 191,594 cf, Depth= 2.80"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.530
98
NP of ponds
17.270
85
Residential, 45.5% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
85
Weighted Average
10.280
54.53% Pervious Area
8.570
45.47% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
32.3
164
0.0200
0.08
Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
6.8
1,511
0.0050
3.72
4.57 Pipe Channel, Storm Sewer
15.00" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
■ Runoff
N
U
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LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 73
Summary for Subcatchment E3: East Onsite Bypass
Runoff = 10.61 cfs @ 3.20 hrs, Volume= 18,981 cf, Depth= 1.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
3.290 70 Woods, Good, HSG C
3.290 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Direct Discharge
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 74
Summary for Subcatchment W1: Pre. West WS
Runoff = 20.04 cfs @ 3.32 hrs, Volume= 48,405 cf, Depth= 1.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
8.390 70 Woods, Good, HSG C
8.390 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
N
U
3
0
LL
Subcatchment W1: Pre. West WS
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
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Summary for Subcatchment W1-A: Pre. West WS
Runoff = 10.01 cfs @ 3.32 hrs, Volume= 24,173 cf, Depth= 1.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
4.190 70 Woods, Good, HSG C
4.190 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 76
Summary for Subcatchment W3: West Onsite Bypass
Runoff = 7.02 cfs @ 3.53 hrs, Volume= 24,231 cf, Depth= 1.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Area (ac) CN Description
4.200 70 Woods, Good, HSG C
4.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
31.5 264 0.0550 0.14 Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 77
Summary for Pond 1 P: West Basin
Inflow Area = 182,604 sf, 49.90% Impervious, Inflow Depth = 2.89" for 25-yr event
Inflow = 24.38 cfs @ 3.19 hrs, Volume= 44,021 cf
Outflow = 5.53 cfs @ 3.49 hrs, Volume= 40,197 cf, Atten= 77%, Lag= 18.1 min
Primary = 5.53 cfs @ 3.49 hrs, Volume= 40,197 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 641.37' @ 3.49 hrs Surf.Area= 15,272 sf Storage= 25,204 cf
Plug -Flow detention time= 769.6 min calculated for 40,180 cf (91% of inflow)
Center -of -Mass det. time= 761.4 min ( 972.5 - 211.1 )
Volume Invert Avail.Storage Storage Description
#1 639.28' 68,819 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
639.28 9,519 0 0
640.00 11,439 7,545 7,545
641.00 13,400 12,420 19,964
642.00 18,522 15,961 35,925
643.00 23,054 20,788 56,713
643.50 25,369 12,106 68,819
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.32' S= 0.0068 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 640.39' 24.00" W x 9.00" H Vert. Orifice/Grate C= 0.600
Limited to weir flow at low heads
#4 Secondary 642.70' 10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=5.53 cfs @ 3.49 hrs HW=641.36' (Free Discharge)
L1=Culvert (Passes 5.53 cfs of 29.35 cfs potential flow)
�__3=Orifi
2=Orifice/Grate (Orifice Controls 0.04 cfs @ 6.88 fps)
ce/Grate (Orifice Controls 5.49 cfs @ 3.66 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=639.28' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 78
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 79
Summary for Pond 2P: West Basin WQv of 12408 @ 640.41
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 640.41' Surf.Area= 12,243 sf Storage= 12,423 cf
Peak Elev= 640.41' @ 0.00 hrs Surf.Area= 12,243 sf Storage= 12,423 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 639.28'
UMMI1
Description
68,842 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
639.28
9,583
0
0
640.00
11,439
7,568
7,568
641.00
13,400
12,420
19,987
642.00
18,522
15,961
35,948
643.00
23,054
20,788
56,736
643.50
25,369
12,106
68,842
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.50' S= 0.0024 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.03 cfs @ 0.00 hrs HW=640.41' (Free Discharge)
L1=Culvert (Passes 0.03 cfs of 24.58 cfs potential flow)
L2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.02 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 80
Pond 2P: West Basin WQv of 12408 @ 640.41
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
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Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 2.11" for 25-yr event
Inflow = 12.54 cfs @ 3.53 hrs, Volume= 64,428 cf
Primary = 12.54 cfs @ 3.53 hrs, Volume= 64,428 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Inflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 82
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
45.47% Impervious,
Inflow Depth = 2.80" for 25-yr event
Inflow =
50.34 cfs @
3.60 hrs, Volume=
191,594 cf
Outflow =
16.21 cfs @
4.28 hrs, Volume=
163,687 cf, Atten= 68%, Lag= 40.8 min
Primary =
16.21 cfs @
4.28 hrs, Volume=
163,687 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 638.44' @ 4.28 hrs Surf.Area= 34,965 sf Storage= 116,377 cf
Plug -Flow detention time= 1,227.6 min calculated for 163,619 cf (85% of inflow)
Center -of -Mass det. time= 1,213.9 min ( 1,455.1 - 241.2 )
Volume
Invert Avail.Storage Storage
Description
#1
634.50' 121,989 cf BMP 1
(Prismatic) Listed below (Recalc)
#2
634.50'
42,682 cf BMP 2
(Prismatic) Listed below (Recalc)
164,671 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
18,335
0
0
635.00
19,462
9,449
9,449
636.00
21,232
20,347
29,796
637.00
22,977
22,105
51,901
638.00
24,759
23,868
75,769
639.00
26,568
25,664
101,432
639.75
28,251
20,557
121,989
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
4,923
0
0
635.00
6,006
2,732
2,732
636.00
7,194
6,600
9,332
637.00
8,067
7,631
16,963
638.00
8,986
8,527
25,489
639.00
9,950
9,468
34,957
639.75
10,648
7,724
42,682
Device Routina Invert Outlet Devices
#1
Primary
630.09'
15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2
Device 1
634.50'
2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
#3
Device 1
637.51'
24.00" W x 9.00" H Vert. Windows X 4.00 C= 0.600
Limited to weir flow at low heads
#4
Secondary
639.10'
10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 83
Primary OutFlow Max=16.21 cfs @ 4.28 hrs HW=638.44' (Free Discharge)
L1=Culvert (Barrel Controls 16.21 cfs @ 13.21 fps)
�2=WQ
Orifice (Passes < 0.21 cfs potential flow)
3=Windows (Passes < 21.05 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)
N
U
3
0
LL
Pond 4P: Prop Retention Pond East
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
E Inflow
R outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 84
Summary for Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 636.40' Surf.Area= 29,473 sf Storage= 50,708 cf
Peak Elev= 636.40' @ 0.00 hrs Surf.Area= 29,473 sf Storage= 50,708 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 634.50'
UMMI1
Description
164,773 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
23,258
0
0
635.00
25,467
12,181
12,181
636.00
28,426
26,947
39,128
637.00
31,044
29,735
68,863
638.00
33,745
32,395
101,257
639.00
36,635
35,190
136,447
639.75
38,899
28,325
164,773
Device Routing Invert Outlet Devices
#1 Primary 630.09' 15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 634.50' 2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.14 cfs @ 0.00 hrs HW=636.40' (Free Discharge)
L1=Culvert (Passes 0.14 cfs of 13.72 cfs potential flow)
L2=WQ Orifice (Orifice Controls 0.14 cfs @ 6.49 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 85
Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 86
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 38.71 % Impervious, Inflow Depth > 2.27" for 25-yr event
Inflow = 17.23 cfs @ 4.03 hrs, Volume= 182,668 cf
Primary = 17.23 cfs @ 4.03 hrs, Volume= 182,668 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
1
1
1
1
1
1
1
1
H 1
= 1
3
0
LL
Pond 6P: East Post Comb
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Inflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 87
Summary for Pond 10P: West -Total Below Normal Pool
Volume
Invert Avail.Storage Storage
Description
#1
634.00'
9,245 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.00'
20,162 cf Main
perm pool (Prismatic) Listed below (Recalc)
29,407 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
326
0
0
635.00
1,193
760
760
636.00
1,482
1,338
2,097
637.00
1,827
1,655
3,752
638.00
2,248
2,038
5,789
639.00
2,936
2,592
8,381
639.28
3,233
864
9,245
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
2,103
0
0
635.00
2,686
2,395
2,395
636.00
3,284
2,985
5,380
637.00
3,929
3,607
8,986
638.00
4,617
4,273
13,259
639.00
5,790
5,204
18,463
639.28
6,350
1,700
20,162

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 88
Summary for Pond 11 P: Retention Pond East below NP
Volume Invert Avail.Storaae Storaae Description
#1
626.48'
6,940 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
626.48'
65,866 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
628.00'
15,630 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
88,437 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
29
0 0
627.00
69
25 25
628.00
187
128 153
629.00
359
273 426
630.00
584
472 898
631.00
860
722 1,620
632.00
1,183
1,022 2,641
633.00
1,550
1,367 4,008
634.00
1,977
1,764 5,771
634.50
2,699
1,169 6,940
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
4,551
0 0
627.00
4,936
2,467 2,467
628.00
5,686
5,311 7,778
629.00
6,482
6,084 13,862
630.00
7,302
6,892 20,754
631.00
8,159
7,731 28,484
632.00
9,057
8,608 37,092
633.00
10,016
9,537 46,629
634.00
13,761
11,889 58,517
634.50
15,636
7,349 65,866
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
628.00
762
0 0
629.00
1,164
963 963
630.00
1,624
1,394 2,357
631.00
2,141
1,883 4,240
632.00
2,715
2,428 6,668
633.00
3,347
3,031 9,699
634.00
4,036
3,692 13,390
634.50
4,923
2,240 15,630

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 89
Summary for Pond 15P: Retention Pond East below NP - without sediment volume
Volume Invert Avail.Storaae Storaae Description
#1
627.48'
6,867 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
627.48'
60,943 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
629.00'
14,667 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
82,477 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
122
0 0
628.00
187
80 80
629.00
359
273 353
630.00
584
472 825
631.00
860
722 1,547
632.00
1,183
1,022 2,568
633.00
1,550
1,367 3,935
634.00
1,977
1,764 5,698
634.50
2,699
1,169 6,867
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
5,293
0 0
628.00
5,686
2,855 2,855
629.00
6,482
6,084 8,939
630.00
7,302
6,892 15,831
631.00
8,159
7,731 23,561
632.00
9,057
8,608 32,169
633.00
10,016
9,537 41,706
634.00
13,761
11,889 53,594
634.50
15,636
7,349 60,943
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
629.00
1,164
0 0
630.00
1,624
1,394 1,394
631.00
2,141
1,883 3,277
632.00
2,715
2,428 5,705
633.00
3,347
3,031 8,736
634.00
4,036
3,692 12,427
634.50
4,923
2,240 14,667

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 90
Summary for Pond 17P: West -Total Below Normal Pool -without sediment volume
Volume
Invert Avail.Storage Storage
Description
#1
634.50'
9,048 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.50'
19,040 cf Main
perm pool (Prismatic) Listed below (Recalc)
28,088 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
1,057
0
0
635.00
1,193
563
563
636.00
1,482
1,338
1,900
637.00
1,827
1,655
3,555
638.00
2,248
2,038
5,592
639.00
2,936
2,592
8,184
639.28
3,233
864
9,048
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
2,404
0
0
635.00
2,686
1,273
1,273
636.00
3,284
2,985
4,258
637.00
3,929
3,607
7,864
638.00
4,617
4,273
12,137
639.00
5,790
5,204
17,341
639.28
6,350
1,700
19,040

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 91
Summary for Subcatchment 3S: West Post
Runoff = 28.40 cfs @ 3.19 hrs, Volume= 51,622 cf, Depth= 3.39"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
2.092 98 Paved parking, HSG C
2.100 74 >75% Grass cover, Good, HSG C
4.192 86 Weighted Average
2.100 50.10% Pervious Area
2.092 49.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Min Tc
N
U
3
0
LL
Subcatchment 3S: West Post
Hydrograph
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 92
Summary for Subcatchment E1: Pre. East WS
Runoff = 32.12 cfs @ 3.88 hrs, Volume= 161,129 cf, Depth= 1.98"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
22.450 70 Woods, Good, HSG C
22.450 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
U
3
0
LL
Subcatchment E1: Pre. East WS
Hydrograph
V 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 93
Summary for Subcatchment El -A: Pre. East WS to BM
Runoff = 26.97 cfs @ 3.88 hrs, Volume= 135,291 cf, Depth= 1.98"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
18.850 70 Woods, Good, HSG C
18.850 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
U
3
0
LL
Subcatchment El -A: Pre. East WS to BMP
Hydrograph
V 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 94
Summary for Subcatchment E2: East Post
Runoff = 59.12 cfs @ 3.59 hrs, Volume= 225,406 cf, Depth= 3.29"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.530
98
NP of ponds
17.270
85
Residential, 45.5% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
85
Weighted Average
10.280
54.53% Pervious Area
8.570
45.47% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
32.3
164
0.0200
0.08
Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
6.8
1,511
0.0050
3.72
4.57 Pipe Channel, Storm Sewer
15.00" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 95
Summary for Subcatchment E3: East Onsite Bypass
Runoff = 13.28 cfs @ 3.20 hrs, Volume= 23,613 cf, Depth= 1.98"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
3.290 70 Woods, Good, HSG C
3.290 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Direct Discharge
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 96
Summary for Subcatchment W1: Pre. West WS
Runoff = 25.19 cfs @ 3.32 hrs, Volume= 60,217 cf, Depth= 1.98"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
8.390 70 Woods, Good, HSG C
8.390 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 97
Summary for Subcatchment W1-A: Pre. West WS
Runoff = 12.58 cfs @ 3.32 hrs, Volume= 30,073 cf, Depth= 1.98"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
4.190 70 Woods, Good, HSG C
4.190 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 98
Summary for Subcatchment W3: West Onsite Bypass
Runoff = 8.84 cfs @ 3.53 hrs, Volume= 30,144 cf, Depth= 1.98"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Area (ac) CN Description
4.200 70 Woods, Good, HSG C
4.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
31.5 264 0.0550 0.14 Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 99
Summary for Pond 1 P: West Basin
Inflow Area = 182,604 sf, 49.90% Impervious, Inflow Depth = 3.39" for 50 yr event
Inflow = 28.40 cfs @ 3.19 hrs, Volume= 51,622 cf
Outflow = 6.63 cfs @ 3.47 hrs, Volume= 47,793 cf, Atten= 77%, Lag= 17.3 min
Primary = 6.63 cfs @ 3.47 hrs, Volume= 47,793 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 641.61' @ 3.47 hrs Surf.Area= 16,540 sf Storage= 29,143 cf
Plug -Flow detention time= 657.7 min calculated for 47,793 cf (93% of inflow)
Center -of -Mass det. time= 648.2 min ( 858.2 - 210.0 )
Volume Invert Avail.Storage Storage Description
#1 639.28' 68,819 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
639.28 9,519 0 0
640.00 11,439 7,545 7,545
641.00 13,400 12,420 19,964
642.00 18,522 15,961 35,925
643.00 23,054 20,788 56,713
643.50 25,369 12,106 68,819
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.32' S= 0.0068 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 640.39' 24.00" W x 9.00" H Vert. Orifice/Grate C= 0.600
Limited to weir flow at low heads
#4 Secondary 642.70' 10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=6.63 cfs @ 3.47 hrs HW=641.61' (Free Discharge)
L1=Culvert (Passes 6.63 cfs of 30.29 cfs potential flow)
�__3=Orifi
2=Orifice/Grate (Orifice Controls 0.04 cfs @ 7.29 fps)
ce/Grate (Orifice Controls 6.59 cfs @ 4.39 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=639.28' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 100
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 101
Summary for Pond 2P: West Basin WQv of 12408 @ 640.41
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 640.41' Surf.Area= 12,243 sf Storage= 12,423 cf
Peak Elev= 640.41' @ 0.00 hrs Surf.Area= 12,243 sf Storage= 12,423 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 639.28'
UMMI1
Description
68,842 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
639.28
9,583
0
0
640.00
11,439
7,568
7,568
641.00
13,400
12,420
19,987
642.00
18,522
15,961
35,948
643.00
23,054
20,788
56,736
643.50
25,369
12,106
68,842
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.50' S= 0.0024 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.03 cfs @ 0.00 hrs HW=640.41' (Free Discharge)
L1=Culvert (Passes 0.03 cfs of 24.58 cfs potential flow)
L2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.02 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 102
Pond 2P: West Basin WQv of 12408 @ 640.41
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 103
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 2.56" for 50 yr event
Inflow = 15.46 cfs @ 3.52 hrs, Volume= 77,937 cf
Primary = 15.46 cfs @ 3.52 hrs, Volume= 77,937 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Pond 3P: West Out
Hydrograph
I 1 nflow
❑ Primary
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 104
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
45.47% Impervious,
Inflow Depth = 3.29" for 50 yr event
Inflow =
59.12 cfs @
3.59 hrs, Volume=
225,406 cf
Outflow =
16.80 cfs @
4.34 hrs, Volume=
197,467 cf, Atten= 72%, Lag= 44.8 min
Primary =
16.80 cfs @
4.34 hrs, Volume=
197,467 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 638.98' @ 4.34 hrs Surf.Area= 36,456 sf Storage= 135,573 cf
Plug -Flow detention time= 1,033.0 min calculated for 197,467 cf (88% of inflow)
Center -of -Mass det. time= 1,018.7 min ( 1,258.7 - 240.1 )
Volume
Invert Avail.Storage Storage
Description
#1
634.50' 121,989 cf BMP 1
(Prismatic) Listed below (Recalc)
#2
634.50'
42,682 cf BMP 2
(Prismatic) Listed below (Recalc)
164,671 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
18,335
0
0
635.00
19,462
9,449
9,449
636.00
21,232
20,347
29,796
637.00
22,977
22,105
51,901
638.00
24,759
23,868
75,769
639.00
26,568
25,664
101,432
639.75
28,251
20,557
121,989
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
4,923
0
0
635.00
6,006
2,732
2,732
636.00
7,194
6,600
9,332
637.00
8,067
7,631
16,963
638.00
8,986
8,527
25,489
639.00
9,950
9,468
34,957
639.75
10,648
7,724
42,682
Device Routina Invert Outlet Devices
#1
Primary
630.09'
15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2
Device 1
634.50'
2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
#3
Device 1
637.51'
24.00" W x 9.00" H Vert. Windows X 4.00 C= 0.600
Limited to weir flow at low heads
#4
Secondary
639.10'
10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 105
Primary OutFlow Max=16.80 cfs @ 4.34 hrs HW=638.98' (Free Discharge)
L1=Culvert (Barrel Controls 16.80 cfs @ 13.69 fps)
�2=WQ
Orifice (Passes < 0.22 cfs potential flow)
3=Windows (Passes < 30.04 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)
N
U
3
0
LL
Pond 4P: Prop Retention Pond East
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
E Inflow
M outflow
❑ Primary
Secondary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 106
Summary for Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 636.40' Surf.Area= 29,473 sf Storage= 50,708 cf
Peak Elev= 636.40' @ 0.00 hrs Surf.Area= 29,473 sf Storage= 50,708 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 634.50'
UMMI1
Description
164,773 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
23,258
0
0
635.00
25,467
12,181
12,181
636.00
28,426
26,947
39,128
637.00
31,044
29,735
68,863
638.00
33,745
32,395
101,257
639.00
36,635
35,190
136,447
639.75
38,899
28,325
164,773
Device Routing Invert Outlet Devices
#1 Primary 630.09' 15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 634.50' 2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.14 cfs @ 0.00 hrs HW=636.40' (Free Discharge)
L1=Culvert (Passes 0.14 cfs of 13.72 cfs potential flow)
L2=WQ Orifice (Orifice Controls 0.14 cfs @ 6.49 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 107
Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 108
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 38.71% Impervious, Inflow Depth > 2.75" for 50 yr event
Inflow = 17.98 cfs @ 4.04 hrs, Volume= 221,080 cf
Primary = 17.98 cfs @ 4.04 hrs, Volume= 221,080 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
N
U
3
0
LL
Pond 6P: East Post Comb
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Inflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 109
Summary for Pond 10P: West -Total Below Normal Pool
Volume
Invert Avail.Storage Storage
Description
#1
634.00'
9,245 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.00'
20,162 cf Main
perm pool (Prismatic) Listed below (Recalc)
29,407 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
326
0
0
635.00
1,193
760
760
636.00
1,482
1,338
2,097
637.00
1,827
1,655
3,752
638.00
2,248
2,038
5,789
639.00
2,936
2,592
8,381
639.28
3,233
864
9,245
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
2,103
0
0
635.00
2,686
2,395
2,395
636.00
3,284
2,985
5,380
637.00
3,929
3,607
8,986
638.00
4,617
4,273
13,259
639.00
5,790
5,204
18,463
639.28
6,350
1,700
20,162

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 110
Summary for Pond 11 P: Retention Pond East below NP
Volume Invert Avail.Storaae Storaae Description
#1
626.48'
6,940 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
626.48'
65,866 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
628.00'
15,630 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
88,437 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
29
0 0
627.00
69
25 25
628.00
187
128 153
629.00
359
273 426
630.00
584
472 898
631.00
860
722 1,620
632.00
1,183
1,022 2,641
633.00
1,550
1,367 4,008
634.00
1,977
1,764 5,771
634.50
2,699
1,169 6,940
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
4,551
0 0
627.00
4,936
2,467 2,467
628.00
5,686
5,311 7,778
629.00
6,482
6,084 13,862
630.00
7,302
6,892 20,754
631.00
8,159
7,731 28,484
632.00
9,057
8,608 37,092
633.00
10,016
9,537 46,629
634.00
13,761
11,889 58,517
634.50
15,636
7,349 65,866
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
628.00
762
0 0
629.00
1,164
963 963
630.00
1,624
1,394 2,357
631.00
2,141
1,883 4,240
632.00
2,715
2,428 6,668
633.00
3,347
3,031 9,699
634.00
4,036
3,692 13,390
634.50
4,923
2,240 15,630

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 111
Summary for Pond 15P: Retention Pond East below NP - without sediment volume
Volume Invert Avail.Storaae Storaae Description
#1
627.48'
6,867 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
627.48'
60,943 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
629.00'
14,667 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
82,477 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
122
0 0
628.00
187
80 80
629.00
359
273 353
630.00
584
472 825
631.00
860
722 1,547
632.00
1,183
1,022 2,568
633.00
1,550
1,367 3,935
634.00
1,977
1,764 5,698
634.50
2,699
1,169 6,867
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
5,293
0 0
628.00
5,686
2,855 2,855
629.00
6,482
6,084 8,939
630.00
7,302
6,892 15,831
631.00
8,159
7,731 23,561
632.00
9,057
8,608 32,169
633.00
10,016
9,537 41,706
634.00
13,761
11,889 53,594
634.50
15,636
7,349 60,943
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
629.00
1,164
0 0
630.00
1,624
1,394 1,394
631.00
2,141
1,883 3,277
632.00
2,715
2,428 5,705
633.00
3,347
3,031 8,736
634.00
4,036
3,692 12,427
634.50
4,923
2,240 14,667

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 112
Summary for Pond 17P: West -Total Below Normal Pool -without sediment volume
Volume
Invert Avail.Storage Storage
Description
#1
634.50'
9,048 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.50'
19,040 cf Main
perm pool (Prismatic) Listed below (Recalc)
28,088 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
1,057
0
0
635.00
1,193
563
563
636.00
1,482
1,338
1,900
637.00
1,827
1,655
3,555
638.00
2,248
2,038
5,592
639.00
2,936
2,592
8,184
639.28
3,233
864
9,048
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
2,404
0
0
635.00
2,686
1,273
1,273
636.00
3,284
2,985
4,258
637.00
3,929
3,607
7,864
638.00
4,617
4,273
12,137
639.00
5,790
5,204
17,341
639.28
6,350
1,700
19,040

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 113
Summary for Subcatchment 3S: West Post
Runoff = 1.51 cfs @ 3.22 hrs, Volume= 3,006 cf, Depth= 0.20"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
2.092 98 Paved parking, HSG C
2.100 74 >75% Grass cover, Good, HSG C
4.192 86 Weighted Average
2.100 50.10% Pervious Area
2.092 49.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Min Tc
❑ Runoff
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 114
Summary for Subcatchment E1: Pre. East WS
Runoff = 0.05 cfs @ 6.16 hrs, Volume= 376 cf, Depth= 0.00"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
22.450 70 Woods, Good, HSG C
22.450 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
3
0
E
Subcatchment E1: Pre. East WS
Hydrograph
0.055
0.05
0.05 cfs
0.045
..............._...............
_............... _............... _..... ...................._................ ..... .............. .E�...........
..._:........... . Q.....Rain al.1..=11....00
0.04
....
...................................................................................................................
......................
......................
......................
Runoff Area=4_0 ac
0.035
......................
......................
......................
......................
FtWnoff Vo�me=7 c
0.03
...
......._1..............d...............d...............
...........
i............... ............... ...... .... ...... ..... .... ...... ..... .. ......
Rt1of [depth-.p0"'
0.025
.... .....
Flo: Len th=1,210'V
0.02
... ..... .... ..... .... .... .....
c-57. m i n
°.015
CN I
0.01
0.005
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 115
Summary for Subcatchment El -A: Pre. East WS to BM
Runoff = 0.04 cfs @ 6.16 hrs, Volume= 315 cf, Depth= 0.00"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
18.850 70 Woods, Good, HSG C
18.850 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
49.7
270
0.0185
0.09
Sheet Flow, East -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
7.3
940
0.0176
2.14
Shallow Concentrated Flow, West Shallow
Unpaved Kv= 16.1 fps
57.0 1,210 Total
N
U
3
0
LL
Subcatchment El -A: Pre. East WS to BMP
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 116
Summary for Subcatchment E2: East Post
Runoff = 2.61 cfs @ 3.71 hrs, Volume= 11,879 cf, Depth= 0.17"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.530
98
NP of ponds
17.270
85
Residential, 45.5% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
85
Weighted Average
10.280
54.53% Pervious Area
8.570
45.47% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
32.3
164
0.0200
0.08
Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
6.8
1,511
0.0050
3.72
4.57 Pipe Channel, Storm Sewer
15.00" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1
N
U
3
0
LL
1,675 Total
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
❑ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 117
Summary for Subcatchment E3: East Onsite Bypass
Runoff = 0.01 cfs @ 5.90 hrs, Volume= 55 cf, Depth= 0.00"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
3.290 70 Woods, Good, HSG C
3.290 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.5 Direct Entry, Direct Discharge
N
U
3
0
LL
Subcatchment E3: East Onsite Bypass
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 118
Summary for Subcatchment W1: Pre. West WS
Runoff = 0.02 cfs @ 5.98 hrs, Volume= 140 cf, Depth= 0.00"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
8.390 70 Woods, Good, HSG C
8.390 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
N
U
3
0
LL
Subcatchment W1: Pre. West WS
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 119
Summary for Subcatchment W1-A: Pre. West WS
Runoff = 0.01 cfs @ 5.98 hrs, Volume= 70 cf, Depth= 0.00"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
4.190 70 Woods, Good, HSG C
4.190 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
11.6
50
0.0243
0.07
Sheet Flow, West -Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
2.1
328
0.0270
2.65
Shallow Concentrated Flow, West Shallow1
Unpaved Kv= 16.1 fps
2.8
540
0.0396
3.20
Shallow Concentrated Flow, W-Shallow2
Unpaved Kv= 16.1 fps
1111.1N' 01liRM OM
N
U
3
0
LL
Subcatchment W1-A: Pre. West WS
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 120
Summary for Subcatchment W3: West Onsite Bypass
Runoff = 0.01 cfs @ 6.04 hrs, Volume= 70 cf, Depth= 0.00"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr WQ Rainfall=1.00"
Area (ac) CN Description
4.200 70 Woods, Good, HSG C
4.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
31.5 264 0.0550 0.14 Sheet Flow, Sheet
Woods: Light underbrush n= 0.400 P2= 3.12"
N
U
3
0
LL
Subcatchment W3: West Onsite Bypass
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 121
Summary for Pond 1 P: West Basin
Inflow Area = 182,604 sf, 49.90% Impervious, Inflow Depth = 0.20" for WQ event
Inflow = 1.51 cfs @ 3.22 hrs, Volume= 3,006 cf
Outflow = 0.01 cfs @ 6.17 hrs, Volume= 2,711 cf, Atten= 99%, Lag= 177.3 min
Primary = 0.01 cfs @ 6.17 hrs, Volume= 2,711 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 639.57' @ 6.17 hrs Surf.Area= 10,295 sf Storage= 2,883 cf
Plug -Flow detention time= 2,310.0 min calculated for 2,710 cf (90% of inflow)
Center -of -Mass det. time= 2,300.3 min ( 2,531.9 - 231.7 )
Volume Invert Avail.Storage Storage Description
#1 639.28' 68,819 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
639.28 9,519 0 0
640.00 11,439 7,545 7,545
641.00 13,400 12,420 19,964
642.00 18,522 15,961 35,925
643.00 23,054 20,788 56,713
643.50 25,369 12,106 68,819
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.32' S= 0.0068 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 640.39' 24.00" W x 9.00" H Vert. Orifice/Grate C= 0.600
Limited to weir flow at low heads
#4 Secondary 642.70' 10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.01 cfs @ 6.17 hrs HW=639.57' (Free Discharge)
L1=Culvert (Passes 0.01 cfs of 19.89 cfs potential flow)
�__3=Orifi
2=Orifice/Grate (Orifice Controls 0.01 cfs @ 2.40 fps)
ce/Grate ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=639.28' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 122
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
ary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 123
Summary for Pond 2P: West Basin WQv of 12408 @ 640.41
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.03 cfs @ 0.00 hrs, Volume= 9,070 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 640.41' Surf.Area= 12,243 sf Storage= 12,423 cf
Peak Elev= 640.41' @ 0.00 hrs Surf.Area= 12,243 sf Storage= 12,423 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 639.28'
UMMI1
Description
68,842 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
639.28
9,583
0
0
640.00
11,439
7,568
7,568
641.00
13,400
12,420
19,987
642.00
18,522
15,961
35,948
643.00
23,054
20,788
56,736
643.50
25,369
12,106
68,842
Device Routing Invert Outlet Devices
#1 Primary 636.60' 24.00" Round Culvert
L= 40.9' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 636.60' / 636.50' S= 0.0024 '/' Cc= 0.900
n= 0.013, Flow Area= 3.14 sf
#2 Device 1 639.28' 1.00" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.03 cfs @ 0.00 hrs HW=640.41' (Free Discharge)
L1=Culvert (Passes 0.03 cfs of 24.58 cfs potential flow)
L2=Orifice/Grate (Orifice Controls 0.03 cfs @ 5.02 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 124
Pond 2P: West Basin WQv of 12408 @ 640.41
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 125
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 0.09" for WQ event
Inflow = 0.02 cfs @ 6.06 hrs, Volume= 2,782 cf
Primary = 0.02 cfs @ 6.06 hrs, Volume= 2,782 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
N
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Pond 3P: West Out
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
C Inflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
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Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
45.47% Impervious,
Inflow Depth = 0.17" for WQ event
Inflow =
2.61 cfs @
3.71 hrs, Volume=
11,879 cf
Outflow =
0.06 cfs @
6.83 hrs, Volume=
10,873 cf, Atten= 98%, Lag= 186.7 min
Primary =
0.06 cfs @
6.83 hrs, Volume=
10,873 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 634.96' @ 6.83 hrs Surf.Area= 25,296 sf Storage= 11,192 cf
Plug -Flow detention time= 1,968.1 min calculated for 10,873 cf (92% of inflow)
Center -of -Mass det. time= 1,957.6 min ( 2,220.6 - 263.0 )
Volume
Invert Avail.Storage Storage
Description
#1
634.50' 121,989 cf BMP 1
(Prismatic) Listed below (Recalc)
#2
634.50'
42,682 cf BMP 2
(Prismatic) Listed below (Recalc)
164,671 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
18,335
0
0
635.00
19,462
9,449
9,449
636.00
21,232
20,347
29,796
637.00
22,977
22,105
51,901
638.00
24,759
23,868
75,769
639.00
26,568
25,664
101,432
639.75
28,251
20,557
121,989
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
4,923
0
0
635.00
6,006
2,732
2,732
636.00
7,194
6,600
9,332
637.00
8,067
7,631
16,963
638.00
8,986
8,527
25,489
639.00
9,950
9,468
34,957
639.75
10,648
7,724
42,682
Device Routina Invert Outlet Devices
#1
Primary
630.09'
15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2
Device 1
634.50'
2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
#3
Device 1
637.51'
24.00" W x 9.00" H Vert. Windows X 4.00 C= 0.600
Limited to weir flow at low heads
#4
Secondary
639.10'
10.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
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Primary OutFlow Max=0.06 cfs @ 6.83 hrs HW=634.96' (Free Discharge)
L1=Culvert (Passes 0.06 cfs of 11.64 cfs potential flow)
�2=WQ
Orifice (Orifice Controls 0.06 cfs @ 2.96 fps)
3=Windows ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L4= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)
N
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Pond 4P: Prop Retention Pond East
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Mry

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 128
Summary for Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.14 cfs @ 0.00 hrs, Volume= 42,603 cf
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Starting Elev= 636.40' Surf.Area= 29,473 sf Storage= 50,708 cf
Peak Elev= 636.40' @ 0.00 hrs Surf.Area= 29,473 sf Storage= 50,708 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert
#1 634.50'
UMMI1
Description
164,773 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
23,258
0
0
635.00
25,467
12,181
12,181
636.00
28,426
26,947
39,128
637.00
31,044
29,735
68,863
638.00
33,745
32,395
101,257
639.00
36,635
35,190
136,447
639.75
38,899
28,325
164,773
Device Routing Invert Outlet Devices
#1 Primary 630.09' 15.00" Round Culvert
L= 49.5' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 630.09' / 630.00' S= 0.0018 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 634.50' 2.00" Vert. WQ Orifice C= 0.600 Limited to weir flow at low heads
Primary OutFlow Max=0.14 cfs @ 0.00 hrs HW=636.40' (Free Discharge)
L1=Culvert (Passes 0.14 cfs of 13.72 cfs potential flow)
L2=WQ Orifice (Orifice Controls 0.14 cfs @ 6.49 fps)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
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Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
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Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 38.71% Impervious, Inflow Depth > 0.14" for WQ event
Inflow = 0.07 cfs @ 5.96 hrs, Volume= 10,928 cf
Primary = 0.07 cfs @ 5.96 hrs, Volume= 10,928 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
N
U
3
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LL
Pond 6P: East Post Comb
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
C Inflow
❑ Primary

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
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Summary for Pond 10P: West -Total Below Normal Pool
Volume
Invert Avail.Storage Storage
Description
#1
634.00'
9,245 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.00'
20,162 cf Main
perm pool (Prismatic) Listed below (Recalc)
29,407 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
326
0
0
635.00
1,193
760
760
636.00
1,482
1,338
2,097
637.00
1,827
1,655
3,752
638.00
2,248
2,038
5,789
639.00
2,936
2,592
8,381
639.28
3,233
864
9,245
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.00
2,103
0
0
635.00
2,686
2,395
2,395
636.00
3,284
2,985
5,380
637.00
3,929
3,607
8,986
638.00
4,617
4,273
13,259
639.00
5,790
5,204
18,463
639.28
6,350
1,700
20,162

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
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Summary for Pond 11 P: Retention Pond East below NP
Volume Invert Avail.Storaae Storaae Description
#1
626.48'
6,940 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
626.48'
65,866 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
628.00'
15,630 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
88,437 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
29
0 0
627.00
69
25 25
628.00
187
128 153
629.00
359
273 426
630.00
584
472 898
631.00
860
722 1,620
632.00
1,183
1,022 2,641
633.00
1,550
1,367 4,008
634.00
1,977
1,764 5,771
634.50
2,699
1,169 6,940
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
626.48
4,551
0 0
627.00
4,936
2,467 2,467
628.00
5,686
5,311 7,778
629.00
6,482
6,084 13,862
630.00
7,302
6,892 20,754
631.00
8,159
7,731 28,484
632.00
9,057
8,608 37,092
633.00
10,016
9,537 46,629
634.00
13,761
11,889 58,517
634.50
15,636
7,349 65,866
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
628.00
762
0 0
629.00
1,164
963 963
630.00
1,624
1,394 2,357
631.00
2,141
1,883 4,240
632.00
2,715
2,428 6,668
633.00
3,347
3,031 9,699
634.00
4,036
3,692 13,390
634.50
4,923
2,240 15,630

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 133
Summary for Pond 15P: Retention Pond East below NP - without sediment volume
Volume Invert Avail.Storaae Storaae Description
#1
627.48'
6,867 cf BMP 1 Forebay (Prismatic) Listed below (Recalc)
#2
627.48'
60,943 cf BMP 1 Main perm pool (Prismatic) Listed below (Recalc)
#3
629.00'
14,667 cf BMP 2 Main perm pool (Prismatic) Listed below (Recalc)
82,477 cf Total Available Storage
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
122
0 0
628.00
187
80 80
629.00
359
273 353
630.00
584
472 825
631.00
860
722 1,547
632.00
1,183
1,022 2,568
633.00
1,550
1,367 3,935
634.00
1,977
1,764 5,698
634.50
2,699
1,169 6,867
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
627.48
5,293
0 0
628.00
5,686
2,855 2,855
629.00
6,482
6,084 8,939
630.00
7,302
6,892 15,831
631.00
8,159
7,731 23,561
632.00
9,057
8,608 32,169
633.00
10,016
9,537 41,706
634.00
13,761
11,889 53,594
634.50
15,636
7,349 60,943
Elevation
Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
629.00
1,164
0 0
630.00
1,624
1,394 1,394
631.00
2,141
1,883 3,277
632.00
2,715
2,428 5,705
633.00
3,347
3,031 8,736
634.00
4,036
3,692 12,427
634.50
4,923
2,240 14,667

20131483-RG1-Det-comb as -built 2020-06-24 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 134
Summary for Pond 17P: West -Total Below Normal Pool -without sediment volume
Volume
Invert Avail.Storage Storage
Description
#1
634.50'
9,048 cf Forebay
(Prismatic) Listed below (Recalc)
#2
634.50'
19,040 cf Main
perm pool (Prismatic) Listed below (Recalc)
28,088 cf Total Available Storage
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
1,057
0
0
635.00
1,193
563
563
636.00
1,482
1,338
1,900
637.00
1,827
1,655
3,555
638.00
2,248
2,038
5,592
639.00
2,936
2,592
8,184
639.28
3,233
864
9,048
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
634.50
2,404
0
0
635.00
2,686
1,273
1,273
636.00
3,284
2,985
4,258
637.00
3,929
3,607
7,864
638.00
4,617
4,273
12,137
639.00
5,790
5,204
17,341
639.28
6,350
1,700
19,040

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
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Events for Subcatchment 3S: West Post
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
9.13
19,921
1.31
2-yr
2.28
9.17
16,225
1.07
10-yr
3.72
17.61
34,910
2.29
25-yr
4.38
24.38
44,021
2.89
50 yr
4.92
28.40
51,622
3.39
WQ
1.00
1.51
3,006
0.20

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
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Events for Subcatchment E1: Pre. East WS
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
4.64
40,258
0.49
2-yr
2.28
4.93
28,901
0.35
10-yr
3.72
17.81
93,434
1.15
25-yr
4.38
25.51
129,521
1.59
50 yr
4.92
32.12
161,129
1.98
WQ
1.00
0.05
376
0.00

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 137
Events for Subcatchment El -A: Pre. East WS to BMP
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
3.89
33,802
0.49
2-yr
2.28
4.14
24,267
0.35
10-yr
3.72
14.95
78,451
1.15
25-yr
4.38
21.42
108,752
1.59
50 yr
4.92
26.97
135,291
1.98
WQ
1.00
0.04
315
0.00

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 138
Events for Subcatchment E2: East Post
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
16.78
85,019
1.24
2-yr
2.28
17.82
68,829
1.01
10-yr
3.72
38.63
151,165
2.21
25-yr
4.38
50.34
191,594
2.80
50 yr
4.92
59.12
225,406
3.29
WQ
1.00
2.61
11,879
0.17

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
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Events for Subcatchment E3: East Onsite Bypass
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
2.40
5,900
0.49
2-yr
2.28
1.91
4,235
0.35
10-yr
3.72
6.80
13,692
1.15
25-yr
4.38
10.61
18,981
1.59
50 yr
4.92
13.28
23,613
1.98
WQ
1.00
0.01
55
0.00

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
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Events for Subcatchment W1: Pre. West WS
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
4.16
15,045
0.49
2-yr
2.28
3.65
10,801
0.35
10-yr
3.72
13.20
34,918
1.15
25-yr
4.38
20.04
48,405
1.59
50 yr
4.92
25.19
60,217
1.98
WQ
1.00
0.02
140
0.00

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
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Events for Subcatchment W1-A: Pre. West WS
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
2.08
7,514
0.49
2-yr
2.28
1.82
5,394
0.35
10-yr
3.72
6.59
17,438
1.15
25-yr
4.38
10.01
24,173
1.59
50 yr
4.92
12.58
30,073
1.98
WQ
1.00
0.01
70
0.00

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
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Events for Subcatchment W3: West Onsite Bypass
Event
Rainfall
(inches)
Runoff
(cfs)
Volume
(cubic -feet)
Depth
(inches)
1 yr
2.58
1.33
7,532
0.49
2-yr
2.28
1.31
5,407
0.35
10-yr
3.72
4.79
17,480
1.15
25-yr
4.38
7.02
24,231
1.59
50 yr
4.92
8.84
30,144
1.98
WQ
1.00
0.01
70
0.00

20131483-RG1-Det-comb as -built 2020-06-24
Prepared by Symanetc
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC
Multi -Event Tables
Printed 7/10/2020
Page 143
Events for Pond 1 P: West Basin
Event
Inflow
Outflow
Primary
Secondary
Elevation
Storage
(cfs)
(cfs)
(cfs)
(cfs)
(feet) (cubic -feet)
1 yr
9.13
0.27
0.27
0.00
640.50
13,524
2-yr
9.17
0.36
0.36
0.00
640.53
13,870
10-yr
17.61
3.69
3.69
0.00
641.08
21,017
25-yr
24.38
5.53
5.53
0.00
641.37
25,204
50 yr
28.40
6.63
6.63
0.00
641.61
29,143
WQ
1.51
0.01
0.01
0.00
639.57
2,883

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 144
Events for Pond 2P: West Basin WQv of 12408 @ 640.41
Event
Inflow
(cfs)
Primary
(cfs)
Elevation
(feet)
Storage
(cubic -feet)
1 yr
0.00
0.03
640.41
12,423
2-yr
0.00
0.03
640.41
12,423
10-yr
0.00
0.03
640.41
12,423
25-yr
0.00
0.03
640.41
12,423
50 yr
0.00
0.03
640.41
12,423
WQ
0.00
0.03
640.41
12,423

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 145
Events for Pond 3P: West Out
Event
Inflow
(cfs)
Primary
(cfs)
Elevation
(feet)
Storage
(cubic -feet)
1 yr
1.36
1.36
0.00
0
2-yr
1.33
1.33
0.00
0
10-yr
8.47
8.47
0.00
0
25-yr
12.54
12.54
0.00
0
50 yr
15.46
15.46
0.00
0
WQ
0.02
0.02
0.00
0

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 146
Events for Pond 4P: Prop Retention Pond East
Event
Inflow
Outflow
Primary
Secondary
Elevation
Storage
(cfs)
(cfs)
(cfs)
(cfs)
(feet)
(cubic -feet)
1 yr
16.78
0.17
0.17
0.00
637.28
77,639
2-yr
17.82
0.16
0.16
0.00
636.93
66,850
10-yr
38.63
10.82
10.82
0.00
638.07
103,467
25-yr
50.34
16.21
16.21
0.00
638.44
116,377
50 yr
59.12
16.80
16.80
0.00
638.98
135,573
WQ
2.61
0.06
0.06
0.00
634.96
11,192

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 147
Events for Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
Event
Inflow
(cfs)
Primary
(cfs)
Elevation
(feet)
Storage
(cubic -feet)
1 yr
0.00
0.14
636.40
50,708
2-yr
0.00
0.14
636.40
50,708
10-yr
0.00
0.14
636.40
50,708
25-yr
0.00
0.14
636.40
50,708
50 yr
0.00
0.14
636.40
50,708
WQ
0.00
0.14
636.40
50,708

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 148
Events for Pond 6P: East Post Comb
Event
Inflow
(cfs)
Primary
(cfs)
Elevation
(feet)
Storage
(cubic -feet)
1 yr
2.44
2.44
0.00
0
2-yr
1.92
1.92
0.00
0
10-yr
11.45
11.45
0.00
0
25-yr
17.23
17.23
0.00
0
50 yr
17.98
17.98
0.00
0
WQ
0.07
0.07
0.00
0

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 149
Events for Pond 10P: West -Total Below Normal Pool
Event Elevation Storage
(feet) (cubic -feet)
1 yr
0.00 0
2-yr
0.00 0
10-yr
0.00 0
25-yr
0.00 0
50 yr
0.00 0
WQ
0.00 0

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 150
Events for Pond 11 P: Retention Pond East below NP
Event
Elevation
(feet)
Storage
(cubic -feet)
1 yr
0.00
0
2-yr
0.00
0
10-yr
0.00
0
25-yr
0.00
0
50 yr
0.00
0
WQ
0.00
0

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 151
Events for Pond 15P: Retention Pond East below NP - without sediment volume
Event
Elevation
(feet)
Storage
(cubic -feet)
1 yr
0.00
0
2-yr
0.00
0
10-yr
0.00
0
25-yr
0.00
0
50 yr
0.00
0
WQ
0.00
0

20131483-RG1-Det-comb as -built 2020-06-24 Multi -Event Tables
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC Page 152
Events for Pond 17P: West -Total Below Normal Pool -without sediment volume
Event Elevation Storage
(feet) (cubic -feet)
1 yr
0.00 0
2-yr
0.00 0
10-yr
0.00 0
25-yr
0.00 0
50 yr
0.00 0
WQ
0.00 0

20131483-RG1-Det-comb as -built 2020-06-24 Table of Contents
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 @ 2020 HydroCAD Software Solutions LLC
TABLE OF CONTENTS
Project Reports
1 Routing Diagram
2 Rainfall Events Listing
1 yr Event
3
Subcat 3S:
West Post
4
Subcat E1:
Pre. East WS
5
Subcat El
-A: Pre. East WS to BMP
6
Subcat E2:
East Post
7
Subcat E3:
East Onsite Bypass
8
Subcat W1: Pre. West WS
9
Subcat W1-A: Pre. West WS
10
Subcat W3:
West Onsite Bypass
11
Pond 1 P:
West Basin
13
Pond 2P:
West Basin WQv of 12408 @ 640.41
15
Pond 3P:
West Out
16
Pond 4P:
Prop Retention Pond East
18
Pond 5P:
Prop Retention Pond East WQv of 50661 @ 636.40
20
Pond 6P:
East Post Comb
21
Pond 10P:
West -Total Below Normal Pool
22
Pond 11 P:
Retention Pond East below NP
23
Pond 15P:
Retention Pond East below NP - without sediment volume
24
Pond 17P:
West -Total Below Normal Pool -without sediment volume
2-yr Event
25 Subcat 3S: West Post
26 Subcat E1: Pre. East WS
27 Subcat El -A: Pre. East WS to BMP
28 Subcat E2: East Post
29 Subcat E3: East Onsite Bypass
30 Subcat W1: Pre. West WS
31 Subcat W1-A: Pre. West WS
32 Subcat W3: West Onsite Bypass
33 Pond 1 P: West Basin
35 Pond 2P: West Basin WQv of 12408 @ 640.41
37 Pond 3P: West Out
38 Pond 4P: Prop Retention Pond East
40 Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
42 Pond 6P: East Post Comb
43 Pond 10P: West -Total Below Normal Pool
44 Pond 11 P: Retention Pond East below NP
45 Pond 15P: Retention Pond East below NP - without sediment volume
46 Pond 17P: West -Total Below Normal Pool -without sediment volume
10-yr Event
47 Subcat 3S: West Post
48 Subcat E1: Pre. East WS
49 Subcat El -A: Pre. East WS to BMP
50 Subcat E2: East Post
51 Subcat E3: East Onsite Bypass

20131483-RG1-Det-comb as -built 2020-06-24 Table of Contents
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 @ 2020 HydroCAD Software Solutions LLC
52 Subcat W1: Pre. West WS
53 Subcat W1-A: Pre. West WS
54 Subcat W3: West Onsite Bypass
55 Pond 1 P: West Basin
57 Pond 2P: West Basin WQv of 12408 @ 640.41
59 Pond 3P: West Out
60 Pond 4P: Prop Retention Pond East
62 Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
64 Pond 6P: East Post Comb
65 Pond 10P: West -Total Below Normal Pool
66 Pond 11 P: Retention Pond East below NP
67 Pond 15P: Retention Pond East below NP - without sediment volume
68 Pond 17P: West -Total Below Normal Pool -without sediment volume
25-yr Event
69 Subcat 3S: West Post
70 Subcat E1: Pre. East WS
71 Subcat El -A: Pre. East WS to BMP
72 Subcat E2: East Post
73 Subcat E3: East Onsite Bypass
74 Subcat W1: Pre. West WS
75 Subcat W1-A: Pre. West WS
76 Subcat W3: West Onsite Bypass
77 Pond 1 P: West Basin
79 Pond 2P: West Basin WQv of 12408 @ 640.41
81 Pond 3P: West Out
82 Pond 4P: Prop Retention Pond East
84 Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
86 Pond 6P: East Post Comb
87 Pond 10P: West -Total Below Normal Pool
88 Pond 11 P: Retention Pond East below NP
89 Pond 15P: Retention Pond East below NP - without sediment volume
90 Pond 17P: West -Total Below Normal Pool -without sediment volume
50 yr Event
91 Subcat 3S: West Post
92 Subcat E1: Pre. East WS
93 Subcat El -A: Pre. East WS to BMP
94 Subcat E2: East Post
95 Subcat E3: East Onsite Bypass
96 Subcat W1: Pre. West WS
97 Subcat W1-A: Pre. West WS
98 Subcat W3: West Onsite Bypass
99 Pond 1 P: West Basin
101 Pond 2P: West Basin WQv of 12408 @ 640.41
103 Pond 3P: West Out
104 Pond 4P: Prop Retention Pond East
106 Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
108 Pond 6P: East Post Comb
109 Pond 10P: West -Total Below Normal Pool
110 Pond 11 P: Retention Pond East below NP
111 Pond 15P: Retention Pond East below NP - without sediment volume

20131483-RG1-Det-comb as -built 2020-06-24 Table of Contents
Prepared by Symanetc Printed 7/10/2020
HydroCAD® 10.10-3a s/n 03828 © 2020 HydroCAD Software Solutions LLC
112 Pond 17P: West -Total Below Normal Pool -without sediment volume
WQ Event
113 Subcat 3S: West Post
114 Subcat E1: Pre. East WS
115 Subcat El -A: Pre. East WS to BMP
116 Subcat E2: East Post
117 Subcat E3: East Onsite Bypass
118 Subcat W1: Pre. West WS
119 Subcat W1-A: Pre. West WS
120 Subcat W3: West Onsite Bypass
121 Pond 1 P: West Basin
123 Pond 2P: West Basin WQv of 12408 @ 640.41
125 Pond 3P: West Out
126 Pond 4P: Prop Retention Pond East
128 Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
130 Pond 6P: East Post Comb
131 Pond 10P: West -Total Below Normal Pool
132 Pond 11 P: Retention Pond East below NP
133 Pond 15P: Retention Pond East below NP - without sediment volume
134 Pond 17P: West -Total Below Normal Pool -without sediment volume
Multi -Event Tables
135 Subcat 3S: West Post
136 Subcat E1: Pre. East WS
137 Subcat El -A: Pre. East WS to BMP
138 Subcat E2: East Post
139 Subcat E3: East Onsite Bypass
140 Subcat W1: Pre. West WS
141 Subcat W1-A: Pre. West WS
142 Subcat W3: West Onsite Bypass
143 Pond 1 P: West Basin
144 Pond 2P: West Basin WQv of 12408 @ 640.41
145 Pond 3P: West Out
146 Pond 4P: Prop Retention Pond East
147 Pond 5P: Prop Retention Pond East WQv of 50661 @ 636.40
148 Pond 6P: East Post Comb
149 Pond 10P: West -Total Below Normal Pool
150 Pond 11 P: Retention Pond East below NP
151 Pond 15P: Retention Pond East below NP - without sediment volume
152 Pond 17P: West -Total Below Normal Pool -without sediment volume

APPENDIX D:
Site Aerial Map

O
Z
W
J
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APPENDIX E:
Soils Map

Soil Map —Union County, North Carolina
534300 534400 534500 534600 534700
35o 8'6"N
534300 534400 534500 534600 534700
Map Scale: 1:5,110 i printed on A portrait (8.5" x 11") sheet.
Meters
$ N 0 50 100 200 300
Feet
0 200 400 800 1200
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: lfrM Zone 17N WGS84
US/bA_ Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Survey
534800 534900
534800 534900
35o 8' 6" N
535000
9/17/2014
Page 1 of 3

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Soil Map —Union County, North Carolina
Map Unit Legend
Union County, North Carolina (NC179)
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
BaB
Badin channery silt loam, 2 to 8
percent slopes
16.1
30.6%
CmB
Cid channery silt loam, 1 to 5
percent slopes
1.5
2.9%
ScA
Secrest-Cid complex, 0 to 3
percent slopes
29.5
56.3%
TaB
Tarrus gravelly silt loam, 2 to 8
percent slopes
5.4
10.2%
Totals for Area of Interest
62.6
100.0%
usoA Natural Resources Web Soil Survey 9/17/2014
4� Conservation Service National Cooperative Soil Survey Page 3 of 3

APPENDIX F:
NCDENR Supplemental BMP Calculations

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
,OJECT INFORMATION
1 Project Name
2 Project Area ac
3 Coastal Wetland Area ac
4 Surface Water Area ac
5 Is this project High or Low Density?
6 1 Does this project use an off -site SCM?
Cou
at Emerald Lake
33.54
0
0.5
High
No
COMPLIANCE WITH 02H .1003(4)
7
Width of vegetated setbacks provided feet
100
8
Will the vegetated setback remain vegetated?
Yes
9
Is BUA other that as listed in .1 0034 c-d out of the setback?
Yes
10
Is streambank stabilization proposed on this project?
No
NUMBER AND TYPE OF SCMs:
11
Infiltration System
0
12
Bioretention Cell
0
13
Wet Pond
2
14
Stormwater Wetland
0
15
Permeable Pavement
0
16
Sand Filter
0
17
Rainwater Harvesting RWH
0
18
Green Roof
0
19
Level Spreader -Filter Strip (IS-FS
0
20
Disconnected Impervious Surface (DIS)
0
21
Treatment Swale
0
22
Dry Pond
0
23
Storm Filter
Silva Cell
Ba filter
TFilterra
0
24
0
25
0
26
0
FORMS LOADED
DESIGNER CERTIFICATION
27 Name and Title:
29 Street address:
30 City. State. Zip:
Brian Rossi. PE/ Proiect Mana
301 McCullough Dr
Charlotte. NC 28262
1 32 I Email: I brossi(a)emht.com
Certification Statement:
I certify, under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or
supervision; that the information provided in the form is, to the best of my knowledge and belief, true, accurate, and complete; and that
the engineering plans, specifications, operation and maintenance agreements and other supporting information are consistent with the
information provided here.
Signature of Designer
Seal
Date

DRAINAGE AREAS
1
Is this a high density project?
Yes
2
If so, number of drainage areas/SCMs
2
3
Is all/part of this project subject to previous rule
versions?
No
FORMS LOADED
A INFORMATION
Entire Site
1
2
M
Wet Ponds
East Pond 1&2
West Pond 3in
ro ect s ft
486769 sf
373357 sf
91119 sf
on subdivided lots (subject to permitting)
7permitting)
358390 sf
266764 sf
74707 sf
outside of subdivided lots (subject to
s
128379 sf
106594 sf
16411 sf
8
Offsite -total area (sq ft
-
sf
13939 sf
9
Offsite BU(sq ft
-
sf
sf
10
Breakdown of new BUA outside subdivided lots:
Parkin (sq ft
5801 sf
5801 sf
sf
Sidewalk (sq ft
20067 sf
15341 sf
2694 sf
Roof (sq ft
6302 sf
4908 sf
sf
Roadway s ft
96210 sf
80545 sf
13717 sf
Future (sq ft
sf
sf
sf
Other, please specify in the comment box
below (sq ft
sf
sf
sf
11
New infiltrating permeable pavement on
subdivided lots (sq ft
sf
sf
sf
12
New infiltrating permeable pavement outside of
Isubdivided lots (sq ft
sf
sf
sf
13permitting)
Exisitng BUA that will remain (not subject to
s ft
sf
sf
sf
14
Existing BUA that is already permitted (sq ft
sf
sf
sf
15
Existing BUA that will be removed (sq ft
sf
sf
sf
16
Percent BUA
34%
45%
50%
17
Design storm inches
(1-yr post) - (1yr
re)
(1-yr post) - (1yr
pre
18
1 Design volume of SCM cu ft
50661 cf
12408 cf
19
Calculation method for design volume
Discrete NRCS
curve Number
Method
Discrete NRCS
curve Number
Method
ADDITIONAL INFORMATION
20
Please use this space to provide any additional information about the
drainage area(s):

WET POND
=Drainage area number
2 Design volume of SCM (cu ft)
GFNFRAI MDC FROM 07H .1090
1&2 3
50661 cf 12408 cf
3
Is the SCM sized to treat the SW from all surfaces at build -out?
Yes
Yes
4
Is the SCM located away from contaminated soils?
Yes
Yes
5
What are the side slopes of the SCM (H:V)?
3:1
3:1
6
Does the SCM have retaining walls, gabion walls or other engineered
side slopes?
No
No
7
Are the inlets, outlets, and receiving stream protected from erosion
(10-year storm)?
Yes
Yes
8
Is there an overflow or bypass for inflow volume in excess of the
design volume?
What is the method for dewatering the SCM for maintenance?
Yes
Yes
9
Drawdown Orifice
Drawdown Orifice
10
If applicable, will the SCM be cleaned out after construction?
Yes
Yes
11
Does the maintenance access comply with General MDC (8)?
Yes
Yes
12
1 Does the drainage easement comply with General MDC (9)?
Yes
Yes
13
If the SCM is on a single family lot, does (will?) the plat comply with
General MDC (10)?
No
No
14
Is there an O&M Agreement that complies with General MDC (11)?
Yes
Yes
15
Is there an O&M Plan that complies with General MDC (12)?
Yes
Yes
16
Does the SCM follow the device specific MDC?
Yes
Yes
17
Was the SCM designed by an NC licensed professional?
Yes
Yes
WET IOND MDC FROM 02H .1053
18
Method used
SA/DA
SA/DA
19
Has a stage/storage table been provided in the calculations?
Yes
Yes
20
Elevation of the excavated main pool depth (bottom of sediment
removal) (fmsl)
626.48
634.00
21
Elevation of the main pool bottom -(top of sediment removal) (fmsl)
627.48
635.00
22
Elevation of the bottom of the vegetated shelf (fmsl)
634.00
638.80
231
Elevation of the permanent pool (fmsl)
634.50
639.28
24
Elevation of the top of the vegetated shelf (fmsl)
635.00
639.80
25
Elevation of the temporary pool (fmsl)
637.51
640.39
26
Surface area of the main permanent pool (square feet)
15636:1
6350:1
27
Volume of the main permanent pool (cubic feet)
60943 cf
19040 cf
28
Average depth of the main pool (feet)
3.90 ft
3.00 ft
29
Average depth equation used
Equation 2
Equation 2
301
If using equation 3, main pool perimeter (feet)
31
If using equation 3, width of submerged veg. shelf (feet)
32
Volume of the forebay (cubic feet)
21534 cf
3456 cf
33
Is this 15-20% of the volume in the main pool?
No
No
34
Clean -out depth for forebay (inches)
84 in
39 in
35
Design volume of SCM (cu ft)
50661 cf
12408 cf
36
Is the outlet an orifice or a weir?
Orifice
Orifice
371
If orifice, orifice diameter (inches)
2 in
1 in
38
If weir, weir height (inches)
39
If weir, weir length (inches)
40
Drawdown time for the temporary pool (days)
4.19
4.84
41
Are the inlet(s) and outlet located in a manner that avoids short-
circuiting?
Yes
Yes
42
Are berms or baffles provided to improve the flow path?
No
No
43
Depth of forebay at entrance (inches)
73 in
70 in
44
Depth of forebay at exit (inches)
78 in
76 in
45
Does water flow out of the forebay in a non -erosive manner?
Yes
Yes
46
Width of the vegetated shelf (feet)
8 ft
loft
47
Slope of vegetated shelf (H:V)
8:1
10:1
48
Does the orifice drawdown from below the top surface of the
permanent pool?
Yes
Yes
49
Does the pond minimize impacts to the receiving channel from the 1-
yr, 24-hr storm?
Yes
Yes
50
Are fountains proposed? (If Y, please provide documentation that
MDC(9) is met.)
Yes
Yes
51
1 Is a trash rack or other device provided to protect the outlet system?
No
No
52
Are the dam and embankment planted in non -clumping turf grass?
Yes
Yes
53
Species of turf that will be used on the dam and embankment
Bermuda Red
Bermuda Red
54
Has a planting plan been provided for the vegetated shelf?
Yes Yes
ADDITIONAL INFORMATION
55
Please use this space to provide any additional information about the
wet pond(s):
33. The basins were designed and approved in 2014, when the 15-20% was
not a requirement. The former DEQ manual requested "Approximately 20%"
volume in the forebays. Both basins provide over 20% of the below normal
pool volume providing extra settling opportunities for both basins.
Wet Pond 3 3:12 PM 7/10/2020