SW3190806_2019-08-27, CY at Emerald Lake, Final Stormwater Report-As-Built-_9/11/2019

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2014-1128
N
%14
SEAL
032959
41
IN
A
Stormwater Management Report
Courtyards at Emerald Lake
`--. Epcon Communities
June 14, 2019
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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 charactoristics 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
1 6-hr Type II
50-year
1 4.92
1 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:
1. 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.
CPv = Post Vol (19,921 cf) - Pre Vol (15,045cf) = 4876 cf. The CPv added to the WQv of
7,595cf = 12,471 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 71,380 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-
1.52
9:�2� 0.01
"�639.57
7-,67-9 7,774
CPv
0.33
638.68
12,485
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
9.27
0.27
640.50
16,082
2
9.33
0.36
640.53
16,433
10
17.92
3.69
641.08
23,570
25
1 22.06
1 5.44
1 641.35
1 27,462
50
1 25.24
1 6.46
1 641.57
1 31,014

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
1 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.
CPv = Post Vol (85,019cf) — Pre Vol (33,802cf) = 51,217cf. The CPv added to the WQv of
31,472 cf = 82,689 cf of volume. The WQv of 31,472 cf with a head of 1.36 feet is controlled
to 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)
mL6-1- 0.64
9-4-2 0.11
635.74
4 31,837
CPv
0.15
637.68
82,713

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
39.33
10.81
638.23
100,109
50
47.57
17.88
638.46
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
10.66
0.14
636.43
51,579
2
10.83
0.13
636.13
42,866
10
28.82
3.65
637.77
93,643
25
37.89
10.13
638.04
102,632
50
45.11
16.60
638.25
109,862
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
2.40
2
4.93
1.97
1.91
10
17.82
6.89
6.82
25
1 25.54
1 10.79
10.78
50
32.21
13.52
17.94

APPENDIX A:
Bio-Retention Sizing Calculations

Date: 7/29/2014
NCDENR BMP Manual
as amended
Project Name: The Courtyards at Emerald Lake - Lawyers Road, Stallings NC
Bioretention Basin No. RG - 1
Rv=runoff coefficient (Runoff/Rainfall)
Rv=0.05+0.009(I)
Rv= Volumetric Runoff Coefficient (Runoff/Rainfall)
" I' = %Impervious
("Simple Method" - Schueler, 1987)
NCDENR Manual July 2007 pg 3-3
Meck. Cty. BMP Manual pg 3.2
Formula:
Af = (WQv) (Df)
((k) (Hf+Df) (Tf))
RAIN GARDEN AREA
Water Quality Protection Volume
WQv = 1.0"RvA Uses 1" Rainfall
12
Engineers, Surveyors, Planners, Scientists
Fill in Values:
"I" =
50 Percent Impervious of Site
"A" =
4.19
Acres 5 Acres Maximum WS A
= 182,516.40 sf
Rv =
0.499
Impervious Area
=1 91,130.00 Isf
Answer:
Compute CNm
WQv =
0.174
Ac.Ft.
Rv = 0.499
7595.2 cf = WQv (1" storm)
WQv = 0.50 inches
5696.4
75% WQv, min. volume to treat
CNm = 93.92 Use to compute Qv,
3.58
cfs Peak Flow for 1" - 6 hr. storm
42.9
ft, Length of Level Spreader for 1 " deep @ 1 fps into Rain Garden
7505
cf, actual WQv provided at control elevation Cntrl EL
= 641.00
Where:
Af = Surface area of Rain Garden (sf)
WQv = Water Quality Volume to be captured
Df = Filter Bed depth (2 feet min. for grasses, 3 to 4 feet for trees)
k = permeability coefficient of filter media (use 2 ft/day for amended soil mix)
See NCDENR BMP Manual pg 12-15, Fig. 12.5
Hf = "Average" height of water above filter bed (Mulch) Must drain within 12 hrs. (NCDENR)
(use 3 to 6 inches, which is one-half of 6 to 12" ponding depth for WQv)
Tf = Design filter bed drain time in days
MAXIMUM 2 days (use 1 day NCDENR, use 1.425 days Meck Cty)
Fill in Values:
"k" = 2 ft/day
Df = 2 ft
Hf = 6 inches
Tf = 1 days
Permeability
Coefficients
Soil Types
k (in/hr)
k (ft/day)
Sand
6
12
Loamy Sand
2
4
Sandy Loam
*0.5 - 1
1-2
Silty Loam
0.02
0.05
Y'
* Use 1.0"/hr, 2 ft/day (NCDENR)
3t 0.50 ft/day (heck Cty)

RAIN GARDEN SIZING
Af =
3038.1
sf, Required media surface area, (accts for infiltration for 6hr rainfall)
3060
sf, Actual Af per plan
Engineers, Surveyors, Planners, Scientists
29.8
sf, Impervious area treated per sf of Rain Garden 3.36 % of impervious site
5%-7% "Normal" range
43
ft, width Approximate size
70
ft, length Surface area can be any shape
10' x 20' Minimum
Water Draw Through Rate:
Darcy's Equation:
Q= (0.0000232)*k*A*(H/L)
Where:
Q= Flow Rate, cfs (of draw) through the Bioretention Soil Q= 0.106 cfs
Mulch thickness =
3
F:Iinches
inches
K = Hydraulic Conductivity of soil (in/hr) (Usually 1/2" / hr) Q (design) = 0.106 cfs IlDrainage
Rock Thickness =
Af = Surface Area of Bio-retention Area (sf) use Q design for routing
H = Height of water above underdrain pipe (ft)
Overall Section Thickness = 3.5 ft
L =Thickness of RG Section (ft), (mulch, media & drainage rock)
Assume (H/L — 1)
Top of Mulch EL = 640.00
Time to Drawdown water from inudation to Saturation (from Hf to Af surface)
Top of Media EL =
639.75
Hf Elevation =
640.50
Volume/Q= 28736 Sec
RG Bottom EL =
636.50
8.0 Hours to saturation level, maximum 12 hrs
Undrn 2feet turnup EL=
638.50
Time to drawdown Media : feet below Af surface
Assume 40% Porosity
Volume = Soil Depth x Area x 0.40
Vol = 2448 cf
DID Media Time = 22989 seconds
6.4 h rs
Total drawdown time from inudation = 14.4 hrs
UNDERDRAIN SIZING
As a rule of thumb, the length of underdrain is based on 10% of Af
Lmin = 102.00 ft, in 3 feet wide stone bed
Dia. min 1 9.2 inches, Use 6 inch dia. minimum PVC or Dbl Wall Slotted HDPE
Number of Undrains req. _ Use Minimum of 2 underdrains
OUTLET STRUCTURE
Structure Type: Box, 36" SO, Inverts
Underdrain: 6" PVC 638.50
Secondary Control: 36"x9" Slot Weir, 4 sides 641.00
Tertiary Control:

APPENDIX B:
Wet Pond Calculations

Courtyards of Emerald Lake
6/14/2019
Stormwater Management Calculations
Wet Pond Design
Notes
Untreated
Predeveloped Calculations
Wet Basin
Discharge
Total Area (ac)
18.85
0
18.85 acres total
Existing Woods HSG C (RCN=70)
18.85
Existing Pond HSG B (RCN=98)
0.00
0.00
Open Grass / Weeds HSG B (RCN=61)
0.00
Open Space Type C (RCN=74)
0.00
Existing Impervious Area
0.00
0.00 acres of impervious area ex condition
Composite RCN
70
70
RCN based on existing conditions
Tc (min)
57
0
1-year Peak (cfs)
3.90
0.00
10-year Peak (cfs)
14.96
0
Post Developed Subareas
Untreated
Subarea
Wet Basin
Discharge
Area (ac)
18.85
0.00
18.85 acres total
% Imp
46%
100%
RCN
78
98
Tc
39.1
0
1-year Peak (cfs)
10.65
0.00
undetained peak
10-year Peak (cfs)
28.80
0.00
undetained 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 Grass / 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 (min)
57
Total 1-year Peak (cfs)
3.90
Total 10-year Peak (cfs)
14.96
Pro -rated 1-year Allowable (cfs)
3.90
Pro -rated 10-year Allowable (cfs)
14.96
Water Quality Calculations
Existing Impervious Area Treated
0.00
0.00 existing impervious area treated
Impervious Area not Treated
0.00
0.00
0.00 prop impery area not treated for WQ
%Imp
46
Rv
0.460
WQv (ac-ft)
0.72
18.84 ac developed
WQv (cu-ft)
31472
75% WQv (cu-ft)
23604
WQv Provided
51748
-
see Hydrocad Output
Water Quality Storage Pipe Design
Lowest Top of Casting (ft)
Invert (ft)
Size (in)
Length (ft)
Top of Pipe Elevation (ft)
Water Quality Elevation (ft) static water quality elevation
Invert StormFilter Out (ft)
Overflow Weir Elevation (ft)

Detention Pipe Design
Min. Overflow Weir Width (ft)
1-year Peak Elevation (ft)
10-year Peak Elevation (ft)
Invert/Normal Pool (ft)
Size (in)
Length (ft)
Top of Pipe/Bank Elevation (ft)
Available Storage (cu-ft)
1st Stage Outlet:
2nd Stage Outlet:
Tailwater Control Orifice (in)
Inlet Pipe Size
Outlet Pipe Size
1-year Peak Elevation (ft)
10-year Peak Elevation (ft)
Wet/Dry/Sand Filter Surface Storage Design
wet basin
Top Sand/Normal Pool (ft)
634.50
Top of Bank (ft)
640.00
2.0" orifice @
1st Stage Outlet:
634.50
(4) 24" wide
2nd Stage Outlet:
weirs @ 637.51
10' wide Trap
3rd Stage Outlet:
weir @ 639.50
15" storm @
Tailwater Control Orifice (in)
632.00
Emergency Spillway Elevation (ft)
639.10
Emergency Spillway Width (ft)
10.00
1-year Peak Elevation (ft)
636.43
10-year Peak Elevation (ft)
637.77
50-year Peak Elevation (ft)
638.26
Results
1-year Peak Release (cfs) na 0.00
1-year Allowable (cfs) na 0.00
10-year Peak Release (cfs) na 0
10-year Allowable (cfs) na 0.00
Total Storage (cu-ft) na 0
10-year Storage Used (cu-ft) na 0

APPENDIX C:
HydroCAD Output

S
EA
Pre. East WS Pre. East WS to BM
E2 4P
East Post Prop Retention Pond 5P
East 6P
Prop Retention Pond
E3 East Post Comb East WQ @ 635.74
East Onsite Bypass
S4
Reach on L
ink

20131483-RG1-Det-comb 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 2
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= 0.00-60.00 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 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 3
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= 0.00-60.00 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 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment E2: East Post
Runoff = 10.61 cfs @ 12.39 hrs, Volume= 57,495 cf, Depth= 0.84"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 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
0.390
98
NP of ponds
17.410
78
Residential, 45% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
78
Weighted Average
10.443
55.40% Pervious Area
8.407
44.60% 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
15.0" 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 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 5
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= 0.00-60.00 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 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 6
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
44.60% Impervious,
Inflow Depth = 0.84" for 1 yr event
Inflow =
10.61 cfs @
12.39 hrs, Volume=
57,495 cf
Outflow =
0.14 cfs @
24.62 hrs, Volume=
22,453 cf, Atten= 99%, Lag= 734.1 min
Primary =
0.14 cfs @
24.62 hrs, Volume=
22,453 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 636.43' @ 24.62 hrs Surf.Area= 29,550 sf Storage= 51,578 cf
Plug -Flow detention time= 1,407.0 min calculated for 22,435 cf (39% of inflow
Center -of -Mass det. time= 1,261.5 min ( 2,150.6 - 889.1 )
Volume
Invert Avail.Storage Storage Description
#1
634.50' 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 Routina Invert
Outlet Devices
#1 Primary 634.50' 2.0" Vert. WQ Orifice C= 0.600
#2 Primary 637.51' 24.0" W x 9.0" H Vert. Windows X 4.00 C= 0.600
#3 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
Primary OutFlow Max=0.14 cfs @ 24.62 hrs HW=636.43' (Free Discharge)
�__2=Windows
1=WQ Orifice (Orifice Controls 0.14 cfs @ 6.54 fps)
( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L3= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb 6-13-19
Type 11 24-hr 1 yr Rainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 7
N
U
Pond 4P: Prop Retention Pond East
Hydrograph
Time (hours)
ary

20131483-RG1-Det-comb 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 8
Summary for Pond 5P: Prop Retention Pond East WQ @ 635.74
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 635.74' Surf.Area= 27,657 sf Storage= 31,837 cf
Peak Elev= 635.74' @ 0.00 hrs Surf.Area= 27,657 sf Storage= 31,837 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
634.50'
2.0" Vert. WQ Orifice C= 0.600
Primary OutFlow Max=0.11 cfs @ 0.00 hrs HW=635.74' (Free Discharge)
L1=WQ Orifice (Orifice Controls 0.11 cfs @ 5.18 fps)

20131483-RG1-Det-comb 6-13-19
Type 11 24-hr 1 yr Rainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 9
Pond 5P: Prop Retention Pond East WQ @ 635.74
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 10
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 37.97% Impervious, Inflow Depth > 0.35" for 1 yr event
Inflow = 2.40 cfs @ 12.01 hrs, Volume= 28,353 cf
Primary = 2.40 cfs @ 12.01 hrs, Volume= 28,353 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 11
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= 0.00-60.00 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
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 12
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= 0.00-60.00 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
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 13
Summary for Subcatchment E2: East Post
Runoff = 10.82 cfs @ 3.66 hrs, Volume= 44,411 cf, Depth= 0.65"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 2-yr Rainfall=2.28"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.390
98
NP of ponds
17.410
78
Residential, 45% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
78
Weighted Average
10.443
55.40% Pervious Area
8.407
44.60% 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
15.0" 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 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 14
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= 0.00-60.00 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
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 15
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
44.60% Impervious,
Inflow Depth = 0.65" for 2-yr event
Inflow =
10.82 cfs @
3.66 hrs, Volume=
44,411 cf
Outflow =
0.13 cfs @
6.93 hrs, Volume=
22,834 cf, Atten= 99%, Lag= 196.2 min
Primary =
0.13 cfs @
6.93 hrs, Volume=
22,834 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 636.13' @ 6.93 hrs Surf.Area= 28,768 sf Storage= 42,865 cf
Plug -Flow detention time= 1,597.6 min calculated for 22,815 cf (51% of inflow
Center -of -Mass det. time= 1,562.9 min ( 1,818.4 - 255.5 )
Volume
Invert Avail.Storage Storage Description
#1
634.50' 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 Routina Invert
Outlet Devices
#1 Primary 634.50' 2.0" Vert. WQ Orifice C= 0.600
#2 Primary 637.51' 24.0" W x 9.0" H Vert. Windows X 4.00 C= 0.600
#3 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
Primary OutFlow Max=0.13 cfs @ 6.93 hrs HW=636.13' (Free Discharge)
�__2=Windows
1=WQOrifice (Orifice Controls 0.13 cfs @ 5.99 fps)
( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L3= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb 6-13-19
Charlotte 6-hr 2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 16
N
U
Pond 4P: Prop Retention Pond East
Hydrograph
Time (hours)
❑ Inflow
M Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 17
Summary for Pond 5P: Prop Retention Pond East WQ @ 635.74
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 635.74' Surf.Area= 27,657 sf Storage= 31,837 cf
Peak Elev= 635.74' @ 0.00 hrs Surf.Area= 27,657 sf Storage= 31,837 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
634.50'
2.0" Vert. WQ Orifice C= 0.600
Primary OutFlow Max=0.11 cfs @ 0.00 hrs HW=635.74' (Free Discharge)
L1=WQ Orifice (Orifice Controls 0.11 cfs @ 5.18 fps)

20131483-RG1-Det-comb 6-13-19
Charlotte 6-hr 2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 18
Pond 5P: Prop Retention Pond East WQ @ 635.74
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 19
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 37.97% Impervious, Inflow Depth > 0.34" for 2-yr event
Inflow = 1.91 cfs @ 3.23 hrs, Volume= 27,070 cf
Primary = 1.91 cfs @ 3.23 hrs, Volume= 27,070 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 20
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= 0.00-60.00 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
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 21
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= 0.00-60.00 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
N
U
3
0
LL
Subcatchment El -A: Pre. East WS to BMP
Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 22
Summary for Subcatchment E2: East Post
Runoff = 28.74 cfs @ 3.63 hrs, Volume= 114,031 cf, Depth= 1.67"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr Rainfall=3.72"
Area (ac) CN Description
0.320
70
Woods, Good, HSG C
0.390
98
NP of ponds
17.410
78
Residential, 45% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
78
Weighted Average
10.443
55.40% Pervious Area
8.407
44.60% 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
15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
Subcatchment E2: East Post
Hydrograph
■ Runoff
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 23
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 24
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
44.60% Impervious,
Inflow Depth = 1.67" for 10-yr event
Inflow =
28.74 cfs @
3.63 hrs, Volume=
114,031 cf
Outflow =
3.65 cfs @
5.22 hrs, Volume=
58,809 cf, Atten= 87%, Lag= 95.5 min
Primary =
3.65 cfs @
5.22 hrs, Volume=
58,809 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 637.77' @ 5.22 hrs Surf.Area= 33,130 sf Storage= 93,646 cf
Plug -Flow detention time= 991.3 min calculated for 58,760 cf (52% of inflow
Center -of -Mass det. time= 959.8 min ( 1,207.7 - 247.9 )
Volume
Invert Avail.Storage Storage Description
#1
634.50' 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 Routina Invert
Outlet Devices
#1 Primary 634.50' 2.0" Vert. WQ Orifice C= 0.600
#2 Primary 637.51' 24.0" W x 9.0" H Vert. Windows X 4.00 C= 0.600
#3 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
Primary OutFlow Max=3.64 cfs @ 5.22 hrs HW=637.77' (Free Discharge)
�__2=Windows
1=WQOrifice (Orifice Controls 0.19 cfs @ 8.60 fps)
(Orifice Controls 3.45 cfs @ 1.64 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L3= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 25
N
U
Pond 4P: Prop Retention Pond East
Hydrograph
Time (hours)
❑ Inflow
M Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 26
Summary for Pond 5P: Prop Retention Pond East WQ @ 635.74
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 635.74' Surf.Area= 27,657 sf Storage= 31,837 cf
Peak Elev= 635.74' @ 0.00 hrs Surf.Area= 27,657 sf Storage= 31,837 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
634.50'
2.0" Vert. WQ Orifice C= 0.600
Primary OutFlow Max=0.11 cfs @ 0.00 hrs HW=635.74' (Free Discharge)
L1=WQ Orifice (Orifice Controls 0.11 cfs @ 5.18 fps)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 27
Pond 5P: Prop Retention Pond East WQ @ 635.74
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 28
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 37.97% Impervious, Inflow Depth > 0.90" for 10-yr event
Inflow = 6.82 cfs @ 3.21 hrs, Volume= 72,501 cf
Primary = 6.82 cfs @ 3.21 hrs, Volume= 72,501 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
N
U
3
0
LL
0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
I nflow
❑ Primary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 29
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= 0.00-60.00 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
Subcatchment E1: Pre. East WS
Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
❑ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 30
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= 0.00-60.00 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 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 31
Summary for Subcatchment E2: East Post
Runoff = 39.25 cfs @ 3.61 hrs, Volume= 150,134 cf, Depth= 2.19"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 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
0.390
98
NP of ponds
17.410
78
Residential, 45% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
78
Weighted Average
10.443
55.40% Pervious Area
8.407
44.60% 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
15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
Subcatchment E2: East Post
Hydrograph
■ Runoff
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 32
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 33
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
44.60% Impervious, Inflow Depth = 2.19" for 25-yr event
Inflow =
39.25 cfs @
3.61 hrs, Volume= 150,134 cf
Outflow =
9.99 cfs @
4.49 hrs, Volume= 94,832 cf, Atten= 75%, Lag= 52.5 min
Primary =
9.99 cfs @
4.49 hrs, Volume= 94,832 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 638.04' @ 4.49 hrs
Surf.Area= 33,848 sf Storage= 102,459 cf
Plug -Flow detention
time= 640.8
min calculated for 94,754 cf (63% of inflow)
Center -of -Mass det. time= 614.3
min ( 860.6 - 246.3 )
Volume
Invert Avail.Storage Storage Description
#1 634.50' 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 Routina Invert
Outlet Devices
#1 Primary 634.50' 2.0" Vert. WQ Orifice C= 0.600
#2 Primary 637.51' 24.0" W x 9.0" H Vert. Windows X 4.00 C= 0.600
#3 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
Primary OutFlow Max=9.97 cfs @ 4.49 hrs HW=638.04' (Free Discharge)
�__2=Windows
1=WQ Orifice (Orifice Controls 0.20 cfs @ 8.95 fps)
(Orifice Controls 9.77 cfs @ 2.33 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L3= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 34
N
U
Pond 4P: Prop Retention Pond East
Hydrograph
Time (hours)
❑ Inflow
M Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 35
Summary for Pond 5P: Prop Retention Pond East WQ @ 635.74
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 635.74' Surf.Area= 27,657 sf Storage= 31,837 cf
Peak Elev= 635.74' @ 0.00 hrs Surf.Area= 27,657 sf Storage= 31,837 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
634.50'
2.0" Vert. WQ Orifice C= 0.600
Primary OutFlow Max=0.11 cfs @ 0.00 hrs HW=635.74' (Free Discharge)
L1=WQ Orifice (Orifice Controls 0.11 cfs @ 5.18 fps)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 36
Pond 5P: Prop Retention Pond East WQ @ 635.74
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 37
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 37.97% Impervious, Inflow Depth > 1.42" for 25-yr event
Inflow = 10.78 cfs @ 4.48 hrs, Volume= 113,814 cf
Primary = 10.78 cfs @ 4.48 hrs, Volume= 113,814 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
0
0
0
Pond 6P: East Post Comb
Hydrograph
V 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
Inflow
❑ Primary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 38
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= 0.00-60.00 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
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 39
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= 0.00-60.00 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
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 40
Summary for Subcatchment E2: East Post
Runoff = 47.46 cfs @ 3.61 hrs, Volume= 180,911 cf, Depth= 2.64"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 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
0.390
98
NP of ponds
17.410
78
Residential, 45% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
78
Weighted Average
10.443
55.40% Pervious Area
8.407
44.60% 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
15.0" 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 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 41
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= 0.00-60.00 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
Subcatchment E3: East Onsite Bypass
Hydrograph
■ Runoff
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 42
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
44.60% Impervious, Inflow Depth = 2.64" for 50 yr event
Inflow =
47.46 cfs @
3.61 hrs, Volume= 180,911 cf
Outflow =
16.88 cfs @
4.26 hrs, Volume= 125,572 cf, Atten= 64%, Lag= 38.8 min
Primary =
16.88 cfs @
4.26 hrs, Volume= 125,572 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 638.26' @ 4.26 hrs
Surf.Area= 34,500 sf Storage= 110,172 cf
Plug -Flow detention
time= 497.9
min calculated for 125,572 cf (69% of inflow)
Center -of -Mass det. time= 472.2
min ( 717.2 - 245.0 )
Volume
Invert Avail.Storage Storage Description
#1 634.50' 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 Routina Invert
Outlet Devices
#1 Primary 634.50' 2.0" Vert. WQ Orifice C= 0.600
#2 Primary 637.51' 24.0" W x 9.0" H Vert. Windows X 4.00 C= 0.600
#3 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
Primary OutFlow Max=16.91 cfs @ 4.26 hrs HW=638.26' (Free Discharge)
�__2=Windows
1=WQ Orifice (Orifice Controls 0.20 cfs @ 9.23 fps)
(Orifice Controls 16.71 cfs @ 2.78 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L3= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 43
N
U
Pond 4P: Prop Retention Pond East
Hydrograph
Time (hours)
ary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 44
Summary for Pond 5P: Prop Retention Pond East WQ @ 635.74
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 635.74' Surf.Area= 27,657 sf Storage= 31,837 cf
Peak Elev= 635.74' @ 0.00 hrs Surf.Area= 27,657 sf Storage= 31,837 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
634.50'
2.0" Vert. WQ Orifice C= 0.600
Primary OutFlow Max=0.11 cfs @ 0.00 hrs HW=635.74' (Free Discharge)
L1=WQ Orifice (Orifice Controls 0.11 cfs @ 5.18 fps)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 45
Pond 5P: Prop Retention Pond East WQ @ 635.74
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 46
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 37.97% Impervious, Inflow Depth > 1.86" for 50 yr event
Inflow = 17.94 cfs @ 4.25 hrs, Volume= 149,185 cf
Primary = 17.94 cfs @ 4.25 hrs, Volume= 149,185 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
N
U
3
0
LL
Pond 6P: East Post Comb
Hydrograph
V 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
Inflow
❑ Primary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 47
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= 0.00-60.00 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
■ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 48
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= 0.00-60.00 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 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 49
Summary for Subcatchment E2: East Post
Runoff = 0.64 cfs @ 3.89 hrs, Volume= 3,993 cf, Depth= 0.06"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 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
0.390
98
NP of ponds
17.410
78
Residential, 45% imp, HSG C
0.730
80
1/2 acre lots, 25% imp, HSG C
18.850
78
Weighted Average
10.443
55.40% Pervious Area
8.407
44.60% 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
15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31'
n= 0.013
39.1 1,675 Total
Subcatchment E2: East Post
Hydrograph
■ Runoff
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 50
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= 0.00-60.00 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
Subcatchment E3: East Onsite Bypass
Hydrograph
■ Runoff
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 51
Summary for Pond 4P: Prop Retention Pond East
Inflow Area =
821,106 sf,
44.60% Impervious,
Inflow Depth = 0.06" for WQ event
Inflow =
0.64 cfs @
3.89 hrs, Volume=
3,993 cf
Outflow =
0.03 cfs @
6.87 hrs, Volume=
2,747 cf, Atten= 95%, Lag= 178.9 min
Primary =
0.03 cfs @
6.87 hrs, Volume=
2,747 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 634.66' @ 6.87 hrs Surf.Area= 23,961 sf Storage= 3,755 cf
Plug -Flow detention time= 1,202.4 min calculated for 2,747 cf (69% of inflow)
Center -of -Mass det. time= 1,172.3 min ( 1,454.3 - 282.0 )
Volume
Invert Avail.Storage Storage Description
#1
634.50' 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 Routina Invert
Outlet Devices
#1 Primary 634.50' 2.0" Vert. WQ Orifice C= 0.600
#2 Primary 637.51' 24.0" W x 9.0" H Vert. Windows X 4.00 C= 0.600
#3 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
Primary OutFlow Max=0.03 cfs @ 6.87 hrs HW=634.66' (Free Discharge)
�__2=Windows
1=WQ Orifice (Orifice Controls 0.03 cfs @ 1.36 fps)
( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=634.50' (Free Discharge)
L3= Broad -Crested Rectangular Weir ( Controls 0.00 cfs)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 52
N
U
Pond 4P: Prop Retention Pond East
Hydrograph
Time (hours)
❑ Inflow
M Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 53
Summary for Pond 5P: Prop Retention Pond East WQ @ 635.74
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.11 cfs @ 0.00 hrs, Volume= 19,622 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 635.74' Surf.Area= 27,657 sf Storage= 31,837 cf
Peak Elev= 635.74' @ 0.00 hrs Surf.Area= 27,657 sf Storage= 31,837 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
634.50'
2.0" Vert. WQ Orifice C= 0.600
Primary OutFlow Max=0.11 cfs @ 0.00 hrs HW=635.74' (Free Discharge)
L1=WQ Orifice (Orifice Controls 0.11 cfs @ 5.18 fps)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 54
Pond 5P: Prop Retention Pond East WQ @ 635.74
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 55
Summary for Pond 6P: East Post Comb
Inflow Area = 964,418 sf, 37.97% Impervious, Inflow Depth > 0.03" for WQ event
Inflow = 0.03 cfs @ 5.98 hrs, Volume= 2,802 cf
Primary = 0.03 cfs @ 5.98 hrs, Volume= 2,802 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
N
U
3
0
LL
Pond 6P: East Post Comb
Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
C Inflow
❑ Primary

Pre. West WS
OW1
Pre. West WS
(3S) � 1P
West Post
S4
Reach on L
ink
West Basin
West
CW3
Ons to Bypass
41
3P
West Out

20131483-RG1-Det-comb 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 2
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= 0.00-60.00 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 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 3
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= 0.00-60.00 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
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 4
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= 0.00-60.00 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 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 5
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= 0.00-60.00 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 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 6
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 @ 14.90 hrs, Volume= 10,751 cf, Atten= 97%, Lag= 174.5 min
Primary = 0.27 cfs @ 14.90 hrs, Volume= 10,751 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 639.28' Surf.Area= 9,519 sf Storage= 2,561 cf
Peak Elev= 640.50' @ 14.90 hrs Surf.Area= 12,421 sf Storage= 16,082 cf (13,521 cf above start)
Plug -Flow detention time= 1,012.3 min calculated for 8,190 cf (41% of inflow)
Center -of -Mass det. time= 685.6 min ( 1,516.0 - 830.5 )
Volume Invert
#1 639.00'
UMMI1
Description
71,380 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
639.00
8,773
0 0
640.00
11,439
10,106 10,106
641.00
13,400
12,420 22,526
642.00
18,522
15,961 38,487
643.00
23,054
20,788 59,275
643.50
25,369
12,106 71,380
Device Routing
Invert
Outlet Devices
#1 Primary
636.60'
24.0" 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'
1.0" Vert. Orifice/Grate C= 0.600
#3 Device 1
640.39'
24.0" W x 9.0" H Vert. Orifice/Grate C= 0.600
#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 @ 14.90 hrs HW=640.50' (Free Discharge)
L1=Culvert (Passes 0.27 cfs of 25.16 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 6-13-19
Type 11 24-hr 1 yr Rainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 7
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Type 1124-hr 1 yrRainfall=2.58"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 8
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 0.60" for 1 yr event
Inflow = 1.36 cfs @ 12.32 hrs, Volume= 18,283 cf
Primary = 1.36 cfs @ 12.32 hrs, Volume= 18,283 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 9
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 10
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 11
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= 0.00-60.00 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
❑ Runoff
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 12
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 13
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 @ 5.33 hrs, Volume= 8,421 cf, Atten= 96%, Lag= 128.3 min
Primary = 0.36 cfs @ 5.33 hrs, Volume= 8,421 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 639.28' Surf.Area= 9,519 sf Storage= 2,561 cf
Peak Elev= 640.53' @ 5.33 hrs Surf.Area= 12,477 sf Storage= 16,433 cf (13,872 cf above start)
Plug -Flow detention time= 1,473.4 min calculated for 5,860 cf (36% of inflow)
Center -of -Mass det. time= 1,030.6 min ( 1,248.9 - 218.2 )
Volume Invert
#1 639.00'
UMMI1
Description
71,380 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
639.00
8,773
0 0
640.00
11,439
10,106 10,106
641.00
13,400
12,420 22,526
642.00
18,522
15,961 38,487
643.00
23,054
20,788 59,275
643.50
25,369
12,106 71,380
Device Routing
Invert
Outlet Devices
#1 Primary
636.60'
24.0" 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'
1.0" Vert. Orifice/Grate C= 0.600
#3 Device 1
640.39'
24.0" W x 9.0" H Vert. Orifice/Grate C= 0.600
#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 @ 5.33 hrs HW=640.53' (Free Discharge)
L1=Culvert (Passes 0.36 cfs of 25.33 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 6-13-19
Charlotte 6-hr 2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 14
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr Rainfall=2.28"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 15
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 0.45" for 2-yr event
Inflow = 1.33 cfs @ 3.61 hrs, Volume= 13,828 cf
Primary = 1.33 cfs @ 3.61 hrs, Volume= 13,828 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
N
U
3
0
LL
Pond 3P: West Out
Hydrograph
0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
I nflow
❑ Primary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 16
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 17
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= 0.00-60.00 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
N
U
3
0
LL
Subcatchment W1: Pre. West WS
Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 18
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 19
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 20
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=
27,053 cf, Atten= 79%, Lag= 24.6 min
Primary =
3.69 cfs @
3.60 hrs, Volume=
27,053 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 639.28' Surf.Area= 9,519 sf Storage= 2,561 cf
Peak Elev= 641.08' @ 3.60 hrs Surf.Area= 13,796 sf Storage= 23,578 cf (21,017 cf above start)
Plug -Flow detention time= 418.3 min calculated for 24,492 cf (70% of inflow)
Center -of -Mass det. time= 357.2 min ( 569.6 - 212.4 )
Volume Invert
#1 639.00'
UMMI1
Description
71,380 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
639.00
8,773
0 0
640.00
11,439
10,106 10,106
641.00
13,400
12,420 22,526
642.00
18,522
15,961 38,487
643.00
23,054
20,788 59,275
643.50
25,369
12,106 71,380
Device Routing
Invert
Outlet Devices
#1 Primary
636.60'
24.0" 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'
1.0" Vert. Orifice/Grate C= 0.600
#3 Device 1
640.39'
24.0" W x 9.0" H Vert. Orifice/Grate C= 0.600
#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 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 21
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 10-yr Rainfall=3.72"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 22
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 1.46" for 10-yr event
Inflow = 8.47 cfs @ 3.56 hrs, Volume= 44,533 cf
Primary = 8.47 cfs @ 3.56 hrs, Volume= 44,533 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Inflow
❑ Primary
N
U
3
0
LL

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 23
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= 0.00-60.00 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
Subcatchment 3S: West Post
Hydrograph
■ Runoff
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 24
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= 0.00-60.00 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 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 25
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 26
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 27
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=
36,151 cf, Atten= 77%, Lag= 18.1 min
Primary =
5.53 cfs @
3.49 hrs, Volume=
36,151 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 639.28' Surf.Area= 9,519 sf Storage= 2,561 cf
Peak Elev= 641.37' @ 3.49 hrs Surf.Area= 15,272 sf Storage= 27,764 cf (25,203 cf above start)
Plug -Flow detention time= 317.8 min calculated for 33,562 cf (76% of inflow)
Center -of -Mass det. time= 277.5 min ( 488.6 - 211.1 )
Volume Invert
#1 639.00'
UMMI1
Description
71,380 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
639.00
8,773
0 0
640.00
11,439
10,106 10,106
641.00
13,400
12,420 22,526
642.00
18,522
15,961 38,487
643.00
23,054
20,788 59,275
643.50
25,369
12,106 71,380
Device Routing
Invert
Outlet Devices
#1 Primary
636.60'
24.0" 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'
1.0" Vert. Orifice/Grate C= 0.600
#3 Device 1
640.39'
24.0" W x 9.0" H Vert. Orifice/Grate C= 0.600
#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 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 28
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 25-yr Rainfall=4.38"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 29
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 1.98" for 25-yr event
Inflow = 12.54 cfs @ 3.53 hrs, Volume= 60,382 cf
Primary = 12.54 cfs @ 3.53 hrs, Volume= 60,382 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Pond 3P: West Out
Hydrograph
Inflow
❑ Primary
V 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 30
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= 0.00-60.00 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
Subcatchment 3S: West Post
Hydrograph
■ Runoff
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 31
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= 0.00-60.00 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
N
U
3
0
LL
Subcatchment W1: Pre. West WS
Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 32
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= 0.00-60.00 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
N
U
3
0
LL
Subcatchment W1-A: Pre. West WS
Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 33
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= 0.00-60.00 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 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 34
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 =
6.64 cfs @
3.47 hrs, Volume=
43,745 cf, Atten= 77%, Lag= 17.3 min
Primary =
6.64 cfs @
3.47 hrs, Volume=
43,745 cf
Secondary =
0.00 cfs @
0.00 hrs, Volume=
0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 639.28' Surf.Area= 9,519 sf Storage= 2,561 cf
Peak Elev= 641.61' @ 3.47 hrs Surf.Area= 16,541 sf Storage= 31,705 cf (29,144 cf above start)
Plug -Flow detention time= 269.7 min calculated for 41,150 cf (80% of inflow)
Center -of -Mass det. time= 237.6 min (447.6 - 210.0 )
Volume Invert
#1 639.00'
UV01
Description
71,380 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
639.00
8,773
0 0
640.00
11,439
10,106 10,106
641.00
13,400
12,420 22,526
642.00
18,522
15,961 38,487
643.00
23,054
20,788 59,275
643.50
25,369
12,106 71,380
Device Routing
Invert
Outlet Devices
#1 Primary
636.60'
24.0" 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'
1.0" Vert. Orifice/Grate C= 0.600
#3 Device 1
640.39'
24.0" W x 9.0" H Vert. Orifice/Grate C= 0.600
#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 30.30 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 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 35
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
❑ Inflow
R Outflow
❑ Primary
Secondary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr 2-yr 50 yr Rainfall=4.92"
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 36
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 2.43" for 50 yr event
Inflow = 15.46 cfs @ 3.52 hrs, Volume= 73,890 cf
Primary = 15.46 cfs @ 3.52 hrs, Volume= 73,890 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Pond 3P: West Out
Hydrograph
I 1 nflow
❑ Primary
V 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 37
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= 0.00-60.00 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

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 38
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= 0.00-60.00 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 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 39
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= 0.00-60.00 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 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
■ Runoff

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 40
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= 0.00-60.00 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"
Subcatchment W3: West Onsite Bypass
Hydrograph
■ Runoff
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 41
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= 2,018 cf, Atten= 99%, Lag= 177.3 min
Primary = 0.01 cfs @ 6.17 hrs, Volume= 2,018 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Starting Elev= 639.28' Surf.Area= 9,519 sf Storage= 2,561 cf
Peak Elev= 639.57' @ 6.17 hrs Surf.Area= 10,295 sf Storage= 5,444 cf (2,883 cf above start)
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= 1,479.0 min ( 1,710.7 - 231.7 )
Volume Invert
#1 639.00'
UMMI1
Description
71,380 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
639.00
8,773
0 0
640.00
11,439
10,106 10,106
641.00
13,400
12,420 22,526
642.00
18,522
15,961 38,487
643.00
23,054
20,788 59,275
643.50
25,369
12,106 71,380
Device Routing
Invert
Outlet Devices
#1 Primary
636.60'
24.0" 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'
1.0" Vert. Orifice/Grate C= 0.600
#3 Device 1
640.39'
24.0" W x 9.0" H Vert. Orifice/Grate C= 0.600
#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 18.40 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 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 42
N
U
Pond 1 P: West Basin
Hydrograph
Time (hours)
ary

20131483-RG1-Det-comb 6-13-19 Charlotte 6-hr2-yr WQ Rainfall= 1. 00 "
Prepared by Symanetc Printed 6/13/2019
HydroCAD® 10.00-15 s/n 03828 © 2015 HydroCAD Software Solutions LLC Page 43
Summary for Pond 3P: West Out
Inflow Area = 365,556 sf, 24.93% Impervious, Inflow Depth > 0.07" for WQ event
Inflow = 0.02 cfs @ 6.06 hrs, Volume= 2,088 cf
Primary = 0.02 cfs @ 6.06 hrs, Volume= 2,088 cf, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
N
U
3
0
LL
Pond 3P: West Out
Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)
C Inflow
❑ Primary

APPENDIX D:
Site Aerial Map

O
Z
W
J
O
O

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

MAP LEGEND
Area of Interest (AOI)
0 Area of Interest (AOI)
Soils
0 Soil Map Unit Polygons
+ Soil Map Unit Lines
Soil Map Unit Points
Special
Point Features
Vo
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
1W
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
o
Sodic Spot
Soil Map —Union County, North Carolina
MAP INFORMATION
Spoil Area
The soil surveys that comprise your AOI were mapped at 1:24,000.
Stony Spot
Warning: Soil Map may not be valid at this scale.
Very Stony Spot
Enlargement of maps beyond the scale of mapping can cause
¢
Wet Spot
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
4
Other
soils that could have been shown at a more detailed scale.
Special Line Features
Please rely on the bar scale on each map sheet for map
Water Features
measurements.
Streams and Canals
Source of Map: Natural Resources Conservation Service
Transportation
Web Soil Survey URL: http://websoilsurvey.nres.usda.gov
4-"
Rails
Coordinate System: Web Mercator (EPSG:3857)
0­0
Interstate Highways
Maps from the Web Soil Survey are based on the Web Mercator
US Routes
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Major Roads
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
Local Roads
This product is generated from the USDA-NRCS certified data as of
Background
the version date(s) listed below.
.
Aerial Photography
Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 14, Dec 21, 2013
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Feb 11, 2011—Mar 2,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
l son Natural Resources Web Soil Survey 9/17/2014
Conservation Service National Cooperative Soil Survey Page 2 of 3

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

Permit No.
(to be provided by DWQ)
R
),C W A TF9
p2 O�
�i v?
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checkkst (Part I//) must be printed, filled out and submitted along with all of the required information.
Project name Courtyards at Emerald Lake
Contact person Robert Cash
Phone number 704-548-0333
Date 14-Jun-19
Drainage area number Project Site Development
Site Characteristics
Drainage area 821,106 ft2
Impervious area, post -development 374,014 ft2
impervious 45.55
Design rainfall depth 1.0 in
Storage Volume: Non -SA Waters
Minimum volume required 31,472 ft'
Volume provided 31,684 ft'
OK, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5" runoff volume
ft3
Pre -development 1-yr, 24-hr runoff
ft3
Post -development 1-yr, 24-hr runoff
ft3
Minimum volume required
ft3
Volume provided
ft3
Peak Flow Calculations
Is the pre/post control ofthe lyr 24hr storm peak flow required?
y (Y or N)
1-yr, 24-hr rainfall depth
2.6 in
Rational C, pre -development
70.00 (unitless)
Rational C, post -development
78.00 (unitless)
Rainfall intensity: 1-yr, 24-hr storm
2.58 inlhr OK
Pre -development 1-yr, 24-hr peak flow
3.90 ft'/sec
Post -development 1-yr, 24-hr peak flow
10.65 ft'/sec
Pre/Post 1-yr, 24-hr peak flow control
6.75 ft'/sec
Elevations
Temporary pool elevation
637.51 finsl
Permanent pool elevation
634.50 finsl
SHWT elevation (approx. at the perm. pool elevation)
finsl
Top of 10ft vegetated shelf elevation
635.00 finsl
Bottom of 1 Oft vegetated shelf elevation
634.00 finsl
Sediment cleanout, top elevation (bottom of pond)
627.00 finsl
Sediment cleanout, bottom elevation
626.00 finsl
Sediment storage provided
1.00 ft
Is there additional volume stored above the state -required temp. pool?
y (Y or N)
Elevation ofthe top ofthe additional volume
637.5 finsl
OK
Surface Areas
Area, temporary pool
25,573 ft2
Area REQUIRED, permanent pool
15,519 ft2
SAIDA ratio
1.89 (unitless)
Area PROVIDED, permanent pool, A,_ ...
19,267 ft2
OK
Area, bottom of 1 Oft vegetated shelf, Aeon ,,au
15,541 ft2
Area, sediment cleanout, top elevation (bottom of pond), Ant -pond
3,278 ft'
Volumes
Volume, temporary pool
31,684 ft'
OK
Volume, permanent pool, VP- 2 1
75,868 ft'
Volume, forebay (sum of forebays if more than one forebay)
15,200 ft'
Forebay % of permanent pool volume
20.0 % %
OK
SAIDA Table Data
Design TSS removal
85 OX
Coastal SAIDA Table Used?
n (Y or N)
Mountain/Piedmont SAIDA Table Used?
y (Y or N)
SAIDA ratio
1.89 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
n (Y or N)
Volume, permanent pool, VP- 2 1
75,868 ft'
Area provided, permanent pool, Apa„ _1
19,267 ft'
Average depth calculated
6.50 ft
OK
Average depth used in SAIDA, d_ (Round to nearest 0.5ft)
6.5 ft
OK
Calculation option 2 used? (See Figure 10-2b)
y (Y or N)
Area provided, permanent pool, Apa„ _1
19,267 ft2
Area, bottom of 1 Oft vegetated shelf, Aeon ,,au
15,541 ft'
Area, sediment cleanout, top elevation (bottom of pond),
3,278 ft2
Anm_po�a
'Depth' (distance b/w bottom of 10ft shelf and top of sediment)
7.00 ft
Average depth calculated
5.50 ft
OK
Average depth used in SAIDA, d_ (Round to down to nearest 0.5ft,
5.5 ft
OK
Drawdown Calculations
Drawdown through orifice?
y (Y or N)
Diameter of orifice (if circular)
2.00 in
Area of orifice (if -non -circular)
in2
Coefficient of discharge (Co)
0.60 (unitless)
Driving head (Ho)
1.36 ft
Drawdown through weir?
n (Y or N)
Weir type
(unitless)
Coefficient of discharge (CJ
(unitless)
Length of weir(L)
ft
Driving head (H)
ft
Pre -development 1-yr, 24-hr peak flow
3.90 ft'/sec
Post -development 1-yr, 24-hr peak flow
10.65 ft'/sec
Storage volume discharge rate (through discharge orifice or weir)
0.12 ft'/sec
Storage volume drawdown time
2.96 days
OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes
3 :1
OK
Vegetated shelf slope
10 :1
OK
Vegetated shelf width
10.0 ft
OK
Length offlowpath to width ratio
3 :1
OK
Length to width ratio
2.0 :1
OK
Trash rack for overflow & orifice?
y (Y or N)
OK
Freeboard provided
1.0 ft
OK
Vegetated filter provided?
n (Y or N)
Insufficient. Vegetated filter required.
Recorded drainage easement provided?
y (Y or N)
OK
Capures all runoff at ultimate build -out?
y (Y or N)
OK
Drain mechanism for maintenance or emergencies is:
pump out
Form SW401-Wet Detention Basin- Rev.94/18/12 Parts I. & II. Design Summary, Page 1 of 1

Permit No.
(to be provided by DWQ)
R
),C W A TF9
p2 O�
�i v?
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checkkst (Part I//) must be printed, filled out and submitted along with all of the required information.
Project name Courtyards at Emerald Lake
Contact person Doug Turney
Phone number 614-775-4213
Date 14-Jun-19
Drainage area number West Basin 3
Site Characteristics
Drainage area 182,516 ft2
Impervious area, post -development 91,076 ft2
impervious 49.90
Design rainfall depth 1.0 in
Storage Volume: Non -SA Waters
Minimum volume required 7,595 ft'
Volume provided 12,155 ft'
OK, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5" runoff volume
ft3
Pre -development 1-yr, 24-hr runoff
ft3
Post -development 1-yr, 24-hr runoff
ft3
Minimum volume required
ft3
Volume provided
ft3
Peak Flow Calculations
Is the pre/post control ofthe lyr 24hr storm peak flow required?
y (Y or N)
1-yr, 24-hr rainfall depth
2.6 in
Rational C, pre -development
70.00 (unitless)
Rational C, post -development
78.00 (unitless)
Rainfall intensity: 1-yr, 24-hr storm
2.58 inlhr
OK
Pre -development 1-yr, 24-hr peak flow
4.16 ft3lsec
Post -development 1-yr, 24-hr peak flow
9.13 ft3lsec
Pre/Post 1-yr, 24-hr peak flow control
4.97 ft'/sec
Elevations
Temporary pool elevation
640.39 finsl
Permanent pool elevation
639.28 finsl
SHWT elevation (approx. at the perm. pool elevation)
finsl
Top of 10ft vegetated shelf elevation
639.80 finsl
Bottom of 1 Oft vegetated shelf elevation
638.80 finsl
Sediment cleanout, top elevation (bottom of pond)
634.40 finsl
Sediment cleanout, bottom elevation
633.40 finsl
Sediment storage provided
1.00 ft
Is there additional volume stored above the state -required temp. pool?
y (Y or N)
Elevation ofthe top ofthe additional volume
640.4 finsl
OK
Surface Areas
Area, temporary pool
12,204 ft2
Area REQUIRED, permanent pool
2,957 ft2
SAIDA ratio
1.62 (unitless)
Area PROVIDED, permanent pool, A,_ ...
9,519 ft2
OK
Area, bottom of 1 Oft vegetated shelf, Aeon 1,au
8,353 ft2
Area, sediment cleanout, top elevation (bottom of pond), Ant -pond
3,029 ft'
Volumes
Volume, temporary pool
12,155 ft'
OK
Volume, permanent pool, VP- 2 1
27,142 ft'
Volume, forebay (sum of forebays if more than one forebay)
6,132 ft'
Forebay % of permanent pool volume
22.6% %
Insufficient forebay volume.
SAIDA Table Data
Design TSS removal
85 OX
Coastal SAIDA Table Used?
n (Y or N)
Mountain/Piedmont SAIDA Table Used?
y (Y or N)
SAIDA ratio
1.62 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
n (Y or N)
Volume, permanent pool, VP- 2 1
27142 ft'
Area provided, permanent pool, Apa„ _1
9,519 ft'
Average depth calculated
2.85 ft
Need 3 ft min.
Average depth used in SAIDA, d_ (Round to nearest 0.5ft)
3.0 ft
OK
Calculation option 2 used? (See Figure 10-2b)
y (Y or N)
Area provided, permanent pool, Apa„ _1
9,519 ft2
Area, bottom of 1 Oft vegetated shelf, Aeon ,,au
8,353 ft2
Area, sediment cleanout, top elevation (bottom of pond),
3 029 ft2
Anm_pona
'Depth' (distance b/w bottom of 10ft shelf and top of sediment)
4.40 ft
Average depth calculated
3.47 ft
OK
Average depth used in SAIDA, d_ (Round to down to nearest 0.5ft,
3.5 ft
OK
Drawdown Calculations
Drawdown through orifice?
y (Y or N)
Diameter of orifice (if circular)
1.00 in
Area of orifice (if -non -circular)
in
Coefficient of discharge (Co)
0.60 (unitless)
Driving head (Ho)
1.11 ft
Drawdown through weir?
n (Y or N)
Weir type
(unitless)
Coefficient of discharge (CJ
(unitless)
Length of weir(L)
ft
Driving head (H)
ft
Pre -development 1-yr, 24-hr peak flow
4.16 ft'/sec
Post -development 1-yr, 24-hr peak flow
9.13 ft'/sec
Storage volume discharge rate (through discharge orifice or weir)
0.01 ft'/sec
Storage volume drawdown time 14.07 days Insufficient drawdown time. Must be within 2-5 days.
Additional Information
Vegetated side slopes
3 :1
OK
Vegetated shelf slope
10 :1
OK
Vegetated shelf width
10.0 ft
OK
Length offlowpath to width ratio
3 :1
OK
Length to width ratio
2.0 :1
OK
Trash rack for overflow & orifice?
y (Y or N)
OK
Freeboard provided
1.9 ft
OK
Vegetated filter provided?
n (Y or N)
Insufficient. Vegetated filter required.
Recorded drainage easement provided?
y (Y or N)
OK
Capures all runoff at ultimate build -out?
y (Y or N)
OK
Drain mechanism for maintenance or emergencies is:
pump out
Form SW401-Wet Detention Basin- Rev.94/18/12 Parts I. & II. Design Summary, Page 1 of 1