SW3171205 - Braeburn (7)

A.
Wet Pond 1
Pre -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 1 Pre-Dev TOC
1: SHEET FLOW
-
SEGMENT ID
A
1 Surface description (table 3-1)
Woods -Li ht
2. Manning's roughness coefficient, n (table 3-1)
04
3 Flow length, L (total 1_5 300 ft) ft
100
4 Two-year 24-hour rainfall, P ........ ....in
312
5. Land slope, s ................. ..ft/ft
00360
6 Tt = 0 007 (nL)^0.8 Compute Tt ........ hr
0.29 +
0.29
P2"0 5 s"0.4
2. SHALLOW CONCENTRATED FLOW
SEGMENT ID
B
C
7. Surface description (paved or unpaved) .........
Unpaved
Unpaved
8. Flow length, L ft
367
361
9 Watercourse slope, s ft/ft
00400
0.0166
10 Average velocity, V (figure 3-1) ...... .......
3 227
2.08
11. Tt = L Compute Tt hrI
003 +
005 0.08
3600 V
3, CHANNEL FLOW
SEGMENT ID
12 Channel type (Pipe or Open Channel)
13 Cross sectional flow area, a. ftZ
14 Wetted perimeter, pw ft
15 Hydraulic radius r = a/pw Compute r ...... A
16 Channel slope, s ft/ft
17 Manning's roughness coefficient, n
18 V = [1 49 r"(2/3) s"(1/2)] / n Compute V ..ft/s
19 Flow length, L ...ft
20 Tt = L Compute Tt ..hr
+
1 0001
3600 V
21. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19)
Hr = 0.37
Min = 22 2
Reference. Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 1 Pre-Dev TOC
Braeburn - Pond 1 - TOC Calcs Pre-Dev
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Phone [phone] Fax [phone]
Runoff Curve Number and Runoff
Project Braeburn
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: ciiesent Developed Pond 1 CN Pre -Development
1. Runoff Curve Number
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
Tbl.
Fig.
I Fig.
of
Group
and hydrologic condition)
2-2
2-312-4
Acres
CN x area
B
Woods, Good condition _
55
1 696
9327
(TaB)
B
Open space, Good condition (grass cover > 75%)
61
0 000
000
(TaB)
B
Dirt Roads_(including right-of-way)
82
0.236
1939
(TaB)
C
Woods, Good condition _
70
9 226
64580
(ScA)
C
Open space, Good condition (grass cover> 75%)
74
0 592
4378
(ScA)
C
Dirt Roads (including right-of-way)
87
0 610
5305
(ScA)
C
Paved areas, streets, roofs, driveways, etc (excl ROW)
_
98
0 099
970
(ScA)
D
Woods, -Good condition
77
0.786
6054
(CmB)
D
Open space, Good condition (grass cover> 75%)
80
0.000
000
(CmB)
D
Dirt Roads (rncluding right-of-way)
89
0.000
000
(CmB)
D
Paved areas, streets, roofs, driveways, etc (excl ROW)
-
98
0.041
401
(CmB)
" Use only one CN source per line
Totals =
13 286
92954
CN (weighted) total product = 929 542 = 700
Use CN= 70
total area 132855
2. Runoff
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall , P (24-hour) in
420
650
1030
Runoff, Q in
146
3 21
650
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
US Department of Agriculture, June 1986
ESP Assocates, PA
PoBox703O
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007i
i
Pond 1 CN Pre -Development
Braeburn - Pond 1 - CN Calcs Pre-Dev
12/14/2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2015 by Autodesk, Inc v10 4
Tuesday, 12 112 / 2017
Hyd. No. 1
POND 1 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 5.507 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 24,256 cuft
Drainage area
= 13.290 ac
Curve number
= 70
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 22.20 min
Total precip.
= 2.58 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
600
5.00
400
300
200
1.00
POND 1 PRE -DEV
Hyd No 1 -- 1 Year
Q (cfs)
6.00
500
400
300
200
1.00
000 - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 1
POND 1 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 9.806 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 38,396 cuft
Drainage area
= 13.290 ac
Curve number
= 70
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 22.20 min
Total precip.
= 3.12 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
1000
MEMM-1110
400
200
000
POND 1 PRE -DEV
Hyd No 1 -- 2 Year
Q (cfs)
1000
400
200
111
l 0 2 4 6 8 10 12 14 16 18 20 22 24 26
I
Hyd No 1 Time (hrs)

Hydr®graph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@) 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 1
POND 1 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 26.15 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 92,772 cuft
Drainage area
= 13.290 ac
Curve number
= 70
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 22.20 min
Total precip.
= 4.80 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
2800
2400
20.00
16.00
12.00
M
400
��
POND 1 PRE -DEV
Hyd No. 1 -- 10 Year
Q (cfs)
2800
24.00
2000
16.00
1200
IM
400
! I0
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 1 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 25 yrs
Time interval
= 2 min
Drainage area
= 13.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.76 in
Storm duration
= 24 hrs
Q (cfs)
40.00
2000
- 10.00
rfivaTil
Tuesday, 12/12/2017
Peak discharge
= 36.72 cfs
Time to peak
= 12.10 hrs
Hyd. volume
= 128,460 cuft
Curve number
= 70
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 22.20 min
Distribution
= Type II
Shape factor
= 484
POND 1 PRE -DEV
Hyd. No. 1 -- 25 Year
I --ijl I I
Q (cfs)
40.00
3000
2000
1000
-M
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D® 2015 by Autodesk, Inc v10
Hyd. No. 1
Time to peak
POND 1 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 50 yrs
Time interval
= 2 min
Drainage area
= 13.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.48 in
Storm duration
= 24 hrs
Q (cfs)
50.00
4000
3000
20.00
1000
Tuesday, 12/12/2017
Peak discharge
= 45.10 cfs
Time to peak
= 12.10 hrs
Hyd. volume
= 156,683 cuft
Curve number
= 70
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 22.20 min
Distribution
= Type II
Shape factor
= 484
POND 1 PRE -DEV
Hyd No. 1 -- 50 Year
Q (cfs)
50.00
40.00
3000
20.00
1000
Rn
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 1
POND 1 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 50.82 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.10 hrs
Time interval
= 2 min
Hyd. volume
= 176,047 cuft
Drainage area
= 13.290 ac
Curve number
= 70
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 22.20 min
Total precip.
= 6.96 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
60.00
5000
40.00
3000
2000
10.00
POND 1 PRE -DEV
Hyd No 1 -- 100 Year
Q (cfs)
6000
50.00
4000
30.00
20.00
1000
0 00 10.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

B.
Wet Pond 1
Post -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 1 Post-Dev TOC
Braeburn - Pond 1 - TOC Calcs Post-Dev
12/14/2017
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 1 Post-Dev TOC
1. SHEET FLOW
SEGMENT ID
A
B
1.
Surface description (table 3-1)
Grass -Short
Woods -Light
2
Manning's roughness coefficient, n (table 3-1) ........
0.15
04
3.
Flow length, L (total L:5 300 ft) ft
60
40
4
Two-year 24-hour rainfall, P ..in
3 12 1
3.12
5
Land slope, s ....... ....... ft/ft
0.0100 1
0.095
6
Tt = 0.007 (nL)^0.8 Compute Tt ... hr
0.15 +
009 024
P2"0.5 s^0 4
2.
SHALLOW CONCENTRATED FLOW
SEGMENT ID
B
C
7
Surface description (paved or unpaved)
Unpaved
Unpaved
8
Flow length, L ...ft
115
32
9
Watercourse slope, s ..ft/ft
0.0608
0.0140
10.
Average velocity, V (figure 3-1)
3.978
1.91
11.
Tt = L Compute Tt ....hr
0.01 +
0.00 001
3600 V
I
CHANNEL FLOW
SEGMENT ID
D
12
Channel type (Pipe or Open Channel)
Pipe
13
Cross sectional flow area, a... .. .. ........... ftZ
3.14
14
Wetted perimeter, pw ..ft
6.28
15.
Hydraulic radius r = a/pw Compute r ft
0.50
16
Channel slope, s ......... ft/ft
0.005
17
Manning's roughness coefficient, n
0.012
18.
V = [1 49 r^(2/3) s^(1/2)] / n Compute V ft/s
5.53
19
Flow length, L ft
558
20.
Tt = L Compute Tt hr
0.03 +
1 0031
3600 V
21.
Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19)
Hr= 0 28
Min = 1678
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 1 Post-Dev TOC
Braeburn - Pond 1 - TOC Calcs Post-Dev
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Phone [phone] Fax [phone]
Runoff Curve Number and Runoff
Project Braeburn
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: Present Develope Pond 1 Post -Development CN
1. 1 RunoffCurve Number
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
of
Tbl.
Fig.
Fig.
Group
and hydrologic condition)
2-2
2-3
2-4
Acres
CN x area
B
Residential, 1/8 acre or less (town houses)
85
1 932
16425
(TaB)
C
Residential, 1/8 acre or less (town houses)
90
10 526
94734
(ScA)
D
Residential, 1/8 acre or less (town houses)
— -- - -
92
0 827
7610
(CmB)
* Use only one CN source per line
Totals =
13 286
118769
CN (weighted) total product = 1187 69 = 894
Use CN= 89
total area 132856
2. Runoff
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall , P (24-hour) in
420
650
1030
Runoff, Q in
3 01
522
895
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
US Department of Agnculture, June 1986
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
ESP Assocates, PA Pond 1 Post -Development CN
PoBox 7030 Braeburn - Pond 1 - CN Calcs Post-Dev
Charlotte NC 28241 12/14/2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D@ 2015 by Autodesk, Inc v10 4
Hyd. No. 2
Time to peak
POND 1 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 13.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2.58 in
Storm duration
= 24 hrs
Tuesday, 12 / 12 / 2017
Peak discharge
= 23.52 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 73,565 cuft
Curve number
= 89
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 16.80 min
Distribution
= Type II
Shape factor
= 484
POND 1 POST -DEV
Q (cfs) Hyd No. 2 -- 1 Year Q (cfs)
2400 2400
2000 20.00
1600 16 00
12.00 1200
8 00 800
400 4.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@) Civil 3DO 2015 by Autodesk, Inc v10 z
Hyd. No. 2
Time to peak
POND 1 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 13.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.12 in
Storm duration
= 24 hrs
Tuesday, 12 112 / 2017
Peak discharge
= 30.85 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 96,902 cuft
Curve number
= 89
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 16.80 min
Distribution
= Type II
Shape factor
= 484
90111sl; W.3I a 11-: LVA
Q (Cfs) Hyd. No. 2 -- 2 Year Q (cfs)
35.00 3500
3000 30.00
2500 2500
20 00 20.00
1500 15.00
10.00 1000
500 500
0.00 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydr®graph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 2
Time to peak
POND 1 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 13.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 4.80 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
4000
30.00
2000
1000
fiYATAIIIII
Tuesday, 12/12/2017
Peak discharge
= 53.95 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 172,745 cuft
Curve number
= 89
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 16.80 min
Distribution
= Type II
Shape factor
= 484
POND 1 POST -DEV
Hyd No 2 -- 10 Year
--
Q (cfs)
60.00
50.00
4000
30.00
2000
1000
MWaTa1
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@) Civil 3D@) 2015 by Autodesk, Inc v10 4
Hyd. No. 2
POND 1 POST -DEV
Hydrograph type
= SCS Runoff
Storm frequency
= 25 yrs
Time interval
= 2 min
Drainage area
= 13.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.76 in
Storm duration
= 24 hrs
Tuesday, 12/12/2017
Peak discharge
= 67.13 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 217,247 cuft
Curve number
= 89
Hydraulic length
= 0 ft
Time of conic. (Tc)
= 16.80 min
Distribution
= Type II
Shape factor
= 484
POND 1 POST -DEV
Q (cfs) Hyd. No 2 -- 25 Year
7000
60.00
5000
40.00
30.00
20.00
1000
Q (cfs)
7000
5000
4000
30.00
2000
10.00
000 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydr®graph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil MID 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 1 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 76.97 cfs
Storm frequency
= 50 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 250,929 cuft
Drainage area
= 13.290 ac
Curve number
= 89
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 16.80 min
Total precip.
= 6.48 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 1 POST -DEV
Q (cfs) Hyd No 2 -- 50 Year
8000
7000
6000
5000
40.00 - -- ---- - — - - --- - -- - - -_ ---- --_ -
3000
2000
1000
Q (cfs)
80.00
7000
5000
4000
3000
2000
1000
000 - 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Hydrograph
Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 /
12 / 2017
Hyd. No. 2
POND 1 POST -DEV
_ Hydrograph type
= SCS Runoff
Peak discharge
= 83.51 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 273,489 cuft
Drainage area
= 13.290 ac
Curve number
= 89
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conic. (Tc)
= 16.80 min
Total precip.
= 6.96 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 1 POST -DEV
Q (cfs)
Hyd No 2 -- 100 Year
Q (cfs)
90.00
90.00
8000
8000
7000
70.00
-
6000
60.00
-
50.00
5000
4000
4000
3000
3000
2000
20 00
-_
-�
—
— -
_
—�
--
1000
10.00
000
000
0 2 4 6 8 10
12 14 16 18 20 22
24 26
Hyd No 2
Time (hrs)

Wet Detention Basin Worksheet
Basin ID Wet Pond #1
Required Designer Input=
Project Name Braebum
Project # FM26 420
Designer C Ludwig
Date 12/08/17
Rev 1 J
Basin Drainage Area Summary
Total Impervious Area
5 57 ac 242,545.66 sf
Total Pervious Area
7 72 ac 336,169.94 sf
Total Future Impervious Area
0 00 ac
Total Area:
13.29 ac 578 715.60 sf Perform Water Balance Calcs.
Percent BUA
41.91%
Calculate The Design Volume
Design Rainfall 1 00 -in
Determine the Runoff Coefficient (Rv) for the 1 -in rainfall
R„=005+09x(1)
1 = 41 91%
Rv = 0.43
Determine the Water Quality Volume (WQv)
WQ„ = Design Rainfall x Rv x Onsite Drainage Area
Design Rainfall is 1 Inch
Rvis043
Drainage Area is 13 29 Acres
WQv = (1 x 0 43 x 16 88)/12
V(design) = 0.47 -ac -ft
20,602.24-cf
Calculate The Required Main Pool Volume
Equation osVolume, VIYP
VMP = 0.87 * H RT * DV
S
Where: 0.87 = Factor to adjust for the volume in the forebay
VMP = Main pool volume, not including the forebay (cubic feet)
HRT = Required hydraulic residence time (14 days)
TS = Average time between storm events (5 days)
DV = Design volume (cubic feet)
Vmp = 50,187.06-cf

Calculate The Required Forebay Volume
V(forebay) = 20% of Vmp =F 10 037.41-cf
Calculate the Permanent Pool Elevation from Proposed Contours with Forebay
Assumed Elev Of Permanent Pool 611.00 -ft
Elevation at Bottom of Littoral Shelf 610.50 -ft
Required Permanent Pool Volume 60,224.47-cf
Forebay Crest Elevation = 609.50 -ft
% Forebay = 1 18.64%1
Required PPE = 607.43 -ft
Proposed PPE = F 611.00 -ft
Basin Detention Stage/Storage Above Permanent Pool Elevation
Elev
Contour Area
Basin Permanent Pool Stage/Storage
Accumul Vol
611 00
44,195 71 sf
Elev
Forebay Area
Main Bay Area
Total Area
Forebay Incr Vol
Forebay
Accumulated
Vol
Main Bay Incr
Vol
Main Bay
Accumulated Vol
Total
Accumulated Vol
60500
2,438 06 sf
19,321 74 sf
21,759 80 sf
0 00-cf
0 00-cf
0 00-cf
0 00-cf
0 00-cf
60600
3,247 64 sf
21,418 06 sf
24,665 70 sf
2,842 85-cf
2,842 85-cf
20,369 90-cf
20,369 90-cf
23,212 75-cf
60700
4,164 37 sf
23,577 81 sf
27,742 18 sf
3,706 01-cf
6,548 86-cf
22,497 94-cf
42,867 84-cf
49,416 69-cf
60800
5,186 94 sf
25,797 50 sf
30,984 44 sf
4,675 66-cf
11,224 51-cf
24,687 66-cf
67,555 49-cf
78,780 00-cf
60900
6,315 36 sf
28,077 13 sf
34,392 49 sf
5,751 15-cf
16,975 66-cf
26,937 32-cf
94,492 81-cf
111,468 47-cf
60950
6,919 27 sf
29,239 57 sf
36,158 84 sf
3,308 66-cf
20,284 32-cf
14,329 18-cf
108,821 98-cf
129,106 30-cf
61000
00 sf
36,305 46 sf
36,305 46 sf
0 00-cf
20,264 32-cf
16,886 26-cf
125,708 24-cf
145,992 56-cf
61050
00 sf
39,641 35 sf
39,641 35 sf
0 00-cf
20,284 32-cf
19,486 70-cf
145,194 94-cf
165,479 26-cf
611 00
00 sf
44,195 71 sf
44,195 71 sf
1 00-cf
20,285 32-cf
20,959 27-cf
166,154 21-cf
186,439 52-cf
% Forebay = 1 18.64%1
Required PPE = 607.43 -ft
Proposed PPE = F 611.00 -ft
Basin Detention Stage/Storage Above Permanent Pool Elevation
Elev
Contour Area
Incr Vol
Accumul Vol
611 00
44,195 71 sf
0 00 cf
186,439 52 cf
611 50
48,907 00 sf
23,275 68 cf
209,715 20 c
61200
50,351 00 sf
24,814 50 cf
234,529 70 cf
61300
53,281 00 sf
51,816 00 cf
286,345 70 cf
61400
56,268 00 sf
54,774 50 cf
341,120 20 c
61500
59,311 00 sf
57,789 50 cf
398,909 70 c
616.00
62,411 00 sf
60,861 00 cf
459,770 70 c
61650
63,984.00 sf
31,598 75 cf
491,369 45 cf
61700
65,567 74 sf
32,387 94 cfj
523,757 39 c
61800
68,782 66 sf
1 67,175 20 cfj
590,932 59­cf

Calculate the Average Depth of the Pond
Equation 2. Average depth when the shelf is not submerged or
the shelf is being included in the average depth calculation
VPP
Div° = APP
Where: Da,,g = Average depth in feet
VPP = Volume of permanent pool (feet3)
APP = Area of permanent pool (feet)
Equation 3. Average depth when the shelf is submerged and
the shelf is being excluded from the average depth calculation
VPP—Vshel f
Davg =
Abottomofshelf
Where: Dag = Average depth in feet
VPP = Total volume of permanent pool (feet3)
Vsheff = Volume over the shelf only (feet3) — see below
Abottom of shelf = Area of wet pond at the bottom of the shelf (feet2)
Vshelf - 0.5 * Depthmax over shelf Perimeterperrn pool * Wfdthsubmerged part ofshelf
Where: Dmax over shelf = Depth of water at the deep side of the shelf as
measured at permanent pool (feet)
Perimeterpermane,t pool = Perimeter of permanent pool at the bottom of the
shelf (feet)
Widths„bmerged part ofshelf = Width from the deep side to the dry side of the
shelf as measured at permanent pool (feet)
PPE =E6150.7520-fftt
P P Penmeter=
Vpp =
App =
Bottom of Shelf Elev =
A(bottom of she = 39,641.35-sf
V(sheif) = 1,156.23-cf
Davg = 4.67 -ft
A(bottom of she = 39,641.35-sf
V(sheif) = 1,156.23-cf
Davg = 4.67 -ft

Determine The Orifice Size of the Riser Structure
1 -year, 24-hour Storm Pre -Development Runoff Volume = 24,256.00-cf (See Hydraflow Hydrographs)
1 -year, 24-hour Storm Post -Development Runoff Volume = 73,565.00-cf (See Hydraflow Hydrogrephs)
Difference = 49,309.00-cf
Vpp = 186,439.52-cf
1 -year, 24-hour Storm Volume in Wet Pond #1= 235,748.52-cf
1 -year, 24-hour Storm Elevation in Wet Pond 4
1 = 612.02 -ft
CA(2gH)0s = Q
C =
0.6
A =
7.07
int
9 =
32.2
ft/sec
H =
0.51
ft
Orifice Diameter =
3
in
Qout =
0.17
cfs
Drawdown Time =
3.38
days

Pond No. 2 - Wet Pond 1 Start at PPE
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
800
Top of pond
Elev 618 00
—700
—600
16 00 ft Riser
WeirA - Elev 615 00
20 00 ft Cipoletti weir
WeirB - Elev 616 00
500
6 0 x 36 0 in orifice
—400
CulvC -Inv 614 00
300
—200
3 00 in orifice
CulvA - 58 5 LF of 36 0 in @ 1.71 %
Gu lvB --Inv-644-00
1 00
0 00
7
Stage (ft)�fF-'
Bottom of pond
Elev 611 00
Section
25 -yr
NTS
10 -yr
100 -yr
2 -yr
50 -yr
1 -yr
Inflow hydrograph = 2 SCS Runoff- POND 1 POST -DEV
Project Braeburn Pond 1.gpw
Thursday, 12 / 14 / 2017

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Pond No. 2 - Wet Pond 1 Start at PPE
Pond Data
Contours -User-defined contour areas
Conic method used for volume calculation Begining
Elevation = 611 00 ft
Stage / Storage Table
Stage (ft) Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
000 611 00
44,196
0
0
050 61150
48,907
23,263
23,263
100 61200
50,351
24,811
48,075
200 61300
53,281
51,804
99,879
300 61400
53,268
53,269
153,148
400 61500
59,311
56,257
209,405
500 61600
62,411
60,848
270,253
550 61650
63,984
31,595
301,848
600 61700
65,568
32,384
334,232
700 61800
68,783
67,162
401,394
Culvert / Orifice Structures
Weir Structures
[A]
[B] [C] [PrfRsr]
[A] [B]
[C] [D]
Rise (in) = 3600
300 600 000
Crest Len (ft)
= 1600 2000
000 000
Span (in) = 3600
3.00 3600 000
Crest EI. (ft)
= 61500 61600
000 000
No. Barrels = 1
1 3 0
Weir Coeff.
= 333 333
333 333
Invert El. (ft) = 611 00
611 00 61400 000
Weir Type
= 1 Clpltl
--- ---
Length (ft) = 5850
050 050 000
Multi -Stage
= Yes No
No No
Slope (%) = 171
000 000 n/a
N -Value = .013
013 013 n/a
Orifice Coeff. = 060
060 060 060
Exfil.(in/hr)
= 0 000 (by Wet area)
Multi -Stage = n/a
Yes Yes No
TW Elev. (ft)
= 000
Note Culvert/Onfice outflows are analyzed under inlet (ic) and outlet (oc) control Weir risers checked for onfice conditions (ic) and submergence (s)
Stage / Storage / Discharge Table
Stage Storage Elevation
Clv A Clv B
CIV C
PrfRsr Wr A
Wr B Wr C
Wr D Exfil User Total
ft cuft ft
cfs cfs
cfs
cfs cfs
cfs cfs
cfs cfs cfs cfs
000 0 611 00
000 000
000
- - 000
000 ---
--- --- --- 0 000
050 23,263 611 50
0 15 ic 0.14 is
000
--- 000
000 ---
--- --- --- 0 143
1 00 48,075 61200
0 23 is 0 22 ic
000
--- 000
000 ---
--- --- --- 0 216
200 99,879 61300
0 33 is 0 32 ic
000
-- 000
000 ---
--- --- --- 0 317
300 153,148 61400
0 41 is 0 39 is
000
--- 000
000 ---
--- --- --- 0 394
400 209,405 61500
19 30 ic 0 36 ic
18 76 is
--- 000
000 ---
--- --- --- 1912
500 270,253 61600
59 23 is 0 16 ic
14 87 is
--- 44 19
s 000 ---
--- --- --- 5923
5.50 301,848 616.50
66 01 ic 0 12 is
10 55 is
--- 55 34
s 2355 ---
--- --- --- 8955
600 334,232 61700
71 06 ic 0 09 is
8 11 ic
--- 62 85
s 6660 ---
--- --- --- 13765
700 401,394 61800
79 34 ic 0 06 is
5 51 ic
--- 73 72
s 18837 ---
--- --- --- 26767

Starmount Cove
CONCRETE ANCHOR BUOYANCY CALCULATIONS
Unit wt. of concrete (pcf) _
Unit wt. of H2O =
TOP OF RISER ELEV. _
INV. OUT OF RISER ELEV. _
INT WIDTH OF RISER=
INT LENGTH OF RISER=
WALL THICK. OF RISER =
BASE THICK. OF RISER =
VOL OF RISER=
BUOYANT FORCE =
VOL. CONC. IN RISER =
SINKING FORCE OF RISER =
CONC. PAD THICKNESS =
CONC. PAD WIDTH/LENGTH =
VOL. OF CONC. PAD =
SINKING FORCE OF PAD =
TOTAL SINKING FORCE =
WET POND #1
CS #1
150 Ib/ft3
62.4 Ib/ft3
615.00 ft
605.00 ft
48 in
48 in
6 in
6 in
262.5 ft3
16380.0 lbs Vol. of Riser x Unit wt. of H2O
102.5 ft3
8979 lbs
24 in
8 ft
128.00 ft3
11212.8 lbs
20191.8 lbs
Factor of safety = SINKING FORCE
BUOYANT FORCE
F.S. = 1.23
Vol. of Conc. x (Unit wt. of Conc. - Unit wt. of H20)
L x W x H/ Pad Thickness
Vol. of Pad x (Unit wt. of Conc. - Unit wt. of HZO)
OK F.S. MUST BE GREATER THAN 1.10

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 3
WET POND 1 PPV
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 2 - POND 1 POST -DEV
Max. Elevation
Reservoir name
= Wet Pond 1 Start at PPE
Max. Storage
Storage Indication method used
Q (cfs)
24.00
2000
1600
12.00
M
4.00
0 10
Hyd No 3
WET POND 1 PPV
Hyd. No 3 -- 1 Year
20 30 40
Hyd No 2
Tuesday, 12/12/2017
= 0.249 cfs
= 24.13 hrs
= 57,439 cult
= 612.29 ft
= 62,983 cuft
Q (cfs)
24.00
20.00
1600
12.00
M
4.00
000
50 60 70 80 90 100
=El Total storage used = 62,983 cuft Time (hrs)

Hyrdrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D0 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 3
WET POND 1 PPV
Hydrograph type
= Reservoir
Peak discharge
= 0.291 cfs
Storm frequency
= 2 yrs
Time to peak
= 24.17 hrs
Time interval
= 2 min
Hyd. volume
= 70,128 cuft
Inflow hyd. No.
= 2 - POND 1 POST -DEV
Max. Elevation
= 612.70 ft
Reservoir name
= Wet Pond 1 Start at PPE
Max. Storage
= 84,411 cuft
Storage Indication method used
WET POND 1 PPV
Q (cfs) Hyd. No. 3 -- 2 Year Q (cfs)
3500 3500
3000 30.00
25.00 2500
2000 20.00
15.00 15.00
10.00 1000
500 500
L0 00 - 000
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No 3 Hyd No 2 [L-LTL1 Total storage used = 84,411 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10.4 Tuesday, 12 / 12 / 2017
Hyd. No. 3
WET POND 1 PPV
Hydrograph type
Storm frequency
= Reservoir
= 10 yrs
Peak discharge
Time to peak
= 0.590 cfs
= 24.10 hrs
Time interval
= 2 min
Hyd. volume
= 103,579 cuft
Inflow hyd. No.
= 2 - POND 1 POST -DEV
Max. Elevation
= 614.02 ft
Reservoir name
= Wet Pond 1 Start at PPE
Max. Storage
= 154,292 cult
Storage Indication method used
WET POND 1 PPV
Q (cfs) Hyd No 3 -- 10 Year
60.00
50.00
40.00
2000
1000
a�111111
Q (cfs)
6000
5000
4000
30.00
2000
10.00
0.00
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No 3 Hyd No 2 ffTFM(-1 Total storage used = 154,292 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 3
WET POND 1 PPV
Hydrograph type
= Reservoir
Peak discharge
= 2.332 cfs
Storm frequency
= 25 yrs
Time to peak
= 15.00 hrs
Time interval
= 2 min
Hyd. volume
= 147,462 cuft
Inflow hyd. No.
= 2 - POND 1 POST -DEV
Max. Elevation
= 614.16 ft
Reservoir name
= Wet Pond 1 Start at PPE
Max. Storage
= 161,888 cuft
Storage Indication method used
Q (cfs
70.00
:1 11
50.00
40.00
30.00
2000
10.00
WET POND 1 PPV
Hyd No 3 -- 25 Year
Q (cfs)
7000
• 1 11,
5000
4000
30.00
2000
1000
000 000
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No. 3 Hyd No 2 [L F111' Total storage used = 161,888 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 3
WET POND 1 PPV
Hydrograph type = Reservoir Peak discharge
Storm frequency = 50 yrs Time to peak
Time interval = 2 min Hyd. volume
Inflow hyd. No. = 2 - POND 1 POST -DEV Max. Elevation
Reservoir name = Wet Pond 1 Start at PPE Max. Storage
Tuesday, 12 / 12 / 2017
= 4.919 cfs
= 13.30 hrs
= 180,959 cuft
= 614.28 ft
= 168,833 cuft
Storage Indication method used
Q (cfs)
WET POND 1 PPV
Hyd No. 3 -- 50 Year
Q (cfs)
8000
8000
70.00
7000
60.00
60.00
-
__
-- -
-- - - -
----
- - - --
-----
----
50.00
--------
--- -
5001
4000
4000
3000
30.00
---
2000
--
--- -----
-
-
---
-
— --
—
—
20.00
�
1000
10.00
0.00
0 10 20 30 40 50 60 70 80 90
_
Hyd No 3 Hyd No 2 TILT_1� D Total storage used = 168,833 cult
000
100
Time (hrs)

11
Hydrograph Report
Peak discharge
Time to peak
Hyd. volume
Max. Elevation
Max. Storage
Storage Indication method used
I
WET POND 1 PPV
Q (cfs) Hyd. No 3 -- 100 Year
Tuesday, 12/12/2017
= 7.778 cfs
= 12.80 hrs
= 203,410 cuft
= 614.39 ft
= 174,963 cuft
Q (cfs)
Iyu uu
Hydraflow Hydrographs Extension for AutoCAD(D Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 3
WET POND 1 PPV
Hydrograph type
= Reservoir
Storm frequency
= 100 yrs
Time interval
= 2 min
Inflow hyd. No.
= 2 - POND 1 POST -DEV
Reservoir name
= Wet Pond 1 Start at PPE
Peak discharge
Time to peak
Hyd. volume
Max. Elevation
Max. Storage
Storage Indication method used
I
WET POND 1 PPV
Q (cfs) Hyd. No 3 -- 100 Year
Tuesday, 12/12/2017
= 7.778 cfs
= 12.80 hrs
= 203,410 cuft
= 614.39 ft
= 174,963 cuft
Q (cfs)
Iyu uu
90.00
8000
8000
7000
7000
60.00
60.00
— -
-
5000
50.00
4000
4000
30.00
--
--�
-----
_
----.
�—
30.00
i 20.00
2000
10 00
10.00
n nn
000
0 10 20 30 40 50 60 70 80 90
Hyd No 3 Hyd No 2 1 ITI-ITII Total storage used = 174,963 cuft
100
Time (hrs)

C.
Wet Pond 2
Pre -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 2 TOC PRE -DEV
Braeburn - Pond 2 - TOC Calcs Pre -Development
12/14/2017
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 2 TOC PRE -DEV
1.
SHEET FLOW
SEGMENT ID
A
1
Surface description (table 3-1)
Woods -Light
2
Manning's roughness coefficient, n (table 3-1) .
0.4
3
Flow length, L (total L5 300 ft) ft
100
4
Two-year 24-hour rainfall, P ....in
312
5.
Land slope, s ......... ..ft/ftl
00190
6
Tt = 0 007 (nL)^0 8 Compute Tt ......... hrl
0.37 +
I 0.37
P2^05s"04
2.
SHALLOW CONCENTRATED FLOW
SEGMENT ID
B
C
7
Surface description (paved or unpaved)
Unpaved
Unpaved
8
Flow length, L ft
510
902
9
Watercourse slope, s ....ft/ft
00217
0.0180
10
Average velocity, V (figure 3-1)
2.377
216
11.
Tt = L Compute Tt ........ .. .. hrl
0.06 +
012 018
3600 V
3.
CHANNEL FLOW
-------------
SEGMENT ID
12.
Channel type (Pipe or Open Channel)
13.
Cross sectional flow area, a. ftZ
14
Wetted perimeter, pw ft
15
Hydraulic radius r = a/pw Computer... .. A
16
Channel slope, s .............. ft/ft
17.
Manning's roughness coefficient, n .
18
V = [1 49 r^(2/3) s^(1/2)] / n Compute V ...... ft/s
19.
Flow length, L .............. ft
20.
Tt = L Compute Tt ........hr
+
0.00
3600 V
21
Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19)
Hr= 0.55
Min = 330,
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 2 TOC PRE -DEV
Braeburn - Pond 2 - TOC Calcs Pre -Development
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Phone [phone] Fax [phone]
Runoff Curve Number and Runoff
Project Braeburn
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: Present Developed Pond 2 CN Pre -Development
1. Runoff Curve -Number _
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
of
Tbl.
Fig.
Fig.
Group
and hydrologic condition)
2-2
2-3
2-4
Acres
CN x area
B
Woods, Good condition
(TaB)
55
0.658
3619
B
Open space, Good_ condition (grass cover > 75%)
---
(TaB)
61
0.000
000
B
Dirt Roads (Including right-of-way)
-— (TaB)
82
0.052
423
C
Woods, Good condition
(ScA)
70
17 446
1221 22
C
Open space, Good condition (grass cover > 75%)
-74
(ScA)
0 037
274
C
Dirt Roads (Including right-of-way)
(ScA) _
87
0.000
000
C
Paved_ areas, streets, roofs, driveways, etc (excl.ROW)
(ScA)
98
0 000
000
D
Woods, Good condition
(CMB)
77
1 514
11654
D
space, Good condition (grass cover > 75%)
_Open
- (CmB)
80
0 000
000
D
Dirt Roads (including right-of-way)
(CmB)
89
0 000
000
D
Paved areas, streets, roofs, driveways, etc (excl ROW)
_
(CmB)
98
0 000
000
* Use only one CN source per line
Totals =
19 706
138093
CN (weighted) total product = 1380 93 = 70 1
Use CN= 70
total area 197062
2. Runoff
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall , P (24-hour) in
420
650
1030
Runoff, Q In
146
3 21
6.50
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
US Department of Agriculture, June 1986
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
ESP Assocates, PA Pond 2 CN Pre -Development
PoBox 7030 Braeburn - Pond 2 - CN Calcs Pre -Development
Charlotte NC 28241 12/14/2017

Hydr®graph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D@ 2015 by Autodesk, Inc v10 4
Hyd. Pio. 1
Time to peak
POND 2 PRE -DEV
Hyd. volume
- Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2.58 in
Storm duration
= 24 hrs
Q (cfs)
700
5.00
4.00
200
1.00
000 -1
0 2 4
Hyd No 1
0
Tuesday, 12/12/2017
Peak discharge
= 6.331 cfs
Time to peak
= 12.27 hrs
Hyd. volume
= 35,785 cuft
Curve number
= 70
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 33.00 min
Distribution
= Type II
Shape factor
= 484
POND 2 PRE -DEV
Hyd No 1 -- 1 Year
Q (cfs)
700
500
4.00
3.00
200
1 00
I I C 1 1 1 1 1 1 1 w 1 0.00
8 10 12 14 16 18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D@ 2015 by Autodesk, Inc v10 4
_ Hyd. N®. 1
Time to peak
POND 2 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.12 in
Storm duration
= 24 hrs
Q (cfs)
12.00
1000
800
600
200
000
Tuesday, 12 / 12 / 2017
Peak discharge
= 11.30 cfs
Time to peak
= 12.23 hrs
Hyd. volume
= 56,644 cuft
Curve number
= 70
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 33.00 min
Distribution
= Type II
Shape factor
= 484
POND 2 PRE -DEV
Hyd No 1 -- 2 Year
Q (cfs)
12.00
1000
4.00
200
000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 2 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 4.80 in
Storm duration
= 24 hrs
Q (cfs)
3500
30.00
2500
2000
1500
1000
500
Tuesday, 12/12/2017
Peak discharge
= 30.67 cfs
Time to peak
= 12.23 hrs
Hyd. volume
= 136,863 cuft
Curve number
= 70
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 33.00 min
Distribution
= Type II
Shape factor
= 484
POND 2 PRE -DEV
Hyd No 1 -- 10 Year
Q (cfs)
35.00
3000
2500
2000
1500
1000
500
Now
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 31DO 2015 by Autodesk, Inc v10 4
_ Hyd. No. 1
Time to peak
POND 2 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 25 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.76 in
Storm duration
= 24 hrs
Q (cfs)
5000
40.00
3000
2000
1000
Tuesday, 12 / 12 / 2017
Peak discharge
= 43.23 cfs
Time to peak
= 12.23 hrs
Hyd. volume
= 189,513 cuft
Curve number
= 70
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 33.00 min
Distribution
= Type II
Shape factor
= 484
POND 2 PRE -DEV
Hyd No. 1 -- 25 Year
Q (cfs)
50.00
40.00
30.00
20.00
10.00
000 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D0 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 2 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 50 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.48 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
40.00
30.00
2000
1000
0 00
Tuesday, 12/12/2017
Peak discharge
= 53.07 cfs
Time to peak
= 12.23 hrs
Hyd. volume
= 231,149 cuft
Curve number
= 70
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 33.00 min
Distribution
= Type II
Shape factor
= 484
POND 2 PRE -DEV
Hyd No 1 -- 50 Year
Q (cfs)
6000
5000
40.00
3000
2000
1000
OWIT11
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@) 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 1
POND 2 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 59.78 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.23 hrs
Time interval
= 2 min
Hyd. volume
= 259,716 cuft
Drainage area
= 19.710 ac
Curve number
= 70
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 33.00 min
Total precip.
= 6.96 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
6000
50.00
4000
3000
20.00
10.00
0 00
POND 2 PRE -DEV
Hyd. No 1 -- 100 Year
Q (cfs)
6000
5000
40.00
3000
2000
1000
EMIT21
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

D.
Wet Pond 2
Post -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 2 TOC Post-Dev
Braeburn - Pond 2 - TOC Calcs Post -Development
12/14/2017
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location
Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 2 TOC Post-Dev
1. SHEET FLOW
.
SEGMENT ID
A
B
1
Surface description (table 3-1)
Grass -Short
Pavement
2.
Manning's roughness coefficient, n (table 3-1)..
0.15
0 011
3.
Flow length, L (total L:5 300 ft) ....ft
75
25
4.
Two-year 24-hour rainfall, P ...in
312
3.12
5.
Land slope, sft/ft
0.0306
0.02
6.
Tt = 0 007 (nL)^0.8 Compute Tt ...............hr
0.11 +
0.01 0.12
P2^05s'04
2. SHALLOW CONCENTRATED FLOW.
.
SEGMENT ID
C
7.
Surface description (paved or unpaved)
Paved
8
Flow length, L ...ft
10
9
Watercourse slope, s ... ............... ft/ft
0.0075
10.
Average velocity, V (figure 3-1) .........
1 760
11
Tt = L Compute Tt hrl
000 +
0.00
3600 V
3.
CHANNEL FLOW
SEGMENT ID
D
12
Channel type (Pipe or Open Channel)
Pipe
13.
Cross sectional flow area, a ............ .......... ft2
3.14
14.
Wetted perimeter, pw ft
6.28
15.
Hydraulic radius r = a/pw Compute r. ....... . ft
050
16
Channel slope, s . ............. ..ft/ft
0 005
17
Manning's roughness coefficient, n .......
0 012
18
V = [1 49 r^(2/3) s^(1/2)] / n Compute V ............ft/s
553
19
Flow length, L ft
944
20.
Tt = L Compute Tt hr
005 +
0 05
3600 V
21
Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19)
Hr = 0.17
Min = 1021
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 2 TOC Post-Dev
Braeburn - Pond 2 - TOC Calcs Post -Development
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Phone [phone] Fax [phone]
Runoff Curve Number and Runoff
Project Braeburn
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: Present evelope Pond 2 Post -Development CIV
1. Runoff Curve Number
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
of
Tbl.
IFig.
I Fig.
Group
and hydrologic condition)
2-2
12-312-41
Acres
CN x area
B
Residential, 1/8 acre or less (town houses)
(TaB)
85
0 710
6032
C
Residential, 1/8 acre or less (town houses) (SCA)
90
17 483
157347
D
_Residential, 1/8 acre or less (town houses)
(CmB)
_
92
1 514
13925
* Use only one CN source per line
Totals =
19 706
177304
CN (weighted) total product = 1773 04 = 900
Use CN= 90
total area 197062
2. Runoff
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall, P (24-hour) in
420
650
1030
Runoff, Q in
311
533
908
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
US Department of Agriculture, June 1986
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
ESP Assocates, PA Pond 2 Post -Development CN
PoBox 7030 Braeburn - Pond 2 - CN Calcs Post -Development
Charlotte NC 28241 12/14/2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 2
Time to peak
POND 2 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
_ Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2.58 in
Storm duration
= 24 hrs
Q (cfs)
5000
40.00
30.00
1000
MIM
Tuesday, 12/12/2017
Peak discharge
= 45.36 cfs
Time to peak
= 12.00 hrs
Hyd. volume
= 118,242 cuft
Curve number
= 90
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.20 min
Distribution
= Type II
Shape factor
= 484
POND 2 POST -DEV
Hyd. No. 2 -- 1 Year
Q (cfs)
5000
40.00
3000
20.00
10.00
row
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@ 2015 by Autodesk, Inc v10 4
Hyd. No. 2
POND 2 POST -DEV
Hydrograph type = SCS Runoff Peak discharge
Storm frequency = 2 yrs Time to peak
Time interval = 2 min Hyd. volume
Drainage area = 19.710 ac Curve number
Basin Slope = 0.0% Hydraulic length
Tc method = User Time of conc. (Tc)
Total precip. = 3.12 in Distribution
Storm duration = 24 hrs Shape factor
Tuesday, 12 / 12 / 2017
= 58.83 cfs
= 12.00 hrs
= 154,548 cuft
= 90
= 0 ft
= 10.20 min
= Type II
= 484
Q (cfs)
POND 2 POST -DEV
Hyd. No 2 -- 2 Year
Q (cfs)
6000
6000
50.00
5000
40.00
40.00
3000
3000
20.00
20.00
1000
1000
000 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@ 2015 by Autodesk, Inc v10 4
Hyd. N®. 2
Time to peak
POND 2 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 4.80 in
Storm duration
= 24 hrs
Q (cfs)
12000
10000
8000
60.00
40.00
2000
Tuesday, 12/12/2017
Peak discharge
= 100.87 cfs
Time to peak
= 12.00 hrs
Hyd. volume
= 271,794 cuft
Curve number
= 90
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.20 min
Distribution
= Type II
Shape factor
= 484
POND 2 POST -DEV
Hyd No 2 -- 10 Year
IL
0.00 -
0
Q (cfs)
120.00
10000
4000
2000
r7i7i1
2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@ 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 2 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 124.75 cfs
Storm frequency
= 25 yrs
Time to peak
= 12.00 hrs
Time interval
= 2 min
Hyd. volume
= 340,314 cuft
Drainage area
= 19.710 ac
Curve number
= 90
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 10.20 min
Total precip.
= 5.76 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 2 POST -DEV
Q (cfs) Hyd No 2 -- 25 Year
140.00
120.00
10000
8000
6000
4000
2000
Q (cfs)
14000
120.00
10000
4000
2000
0 00 0 00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 2
Time to peak
POND 2 POST -DEV
Hyd. volume
-- Hydrograph type
= SCS Runoff
Storm frequency
= 50 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.48 in
Storm duration
= 24 hrs
Tuesday, 12 / 12 / 2017
Peak discharge
= 142.57 cfs
Time to peak
= 12.00 hrs
Hyd. volume
= 392,099 cuft
Curve number
= 90
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.20 min
Distribution
= Type II
Shape factor
= 484
POND 2 POST -DEV
Q (cfs) Hyd. No 2 -- 50 Year Q (cfs)
160.00
160.00
14000
14000
--
12000
_-- _
_.--
_w_._
---
_ --__
_._�
�_-_-.
�_-�
_--•
--_-
�
__--
120.00
10000
10000
8000
8000
6000
60.00
_
4000
4000
20.00
2000
000 _ - -- -- ---- - - - _— 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 2
Time to peak
POND 2 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 19.710 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.96 in
Storm duration
= 24 hrs
Q (cfs)
160.00
140.00
120.00
10000
:1 11
6000
4000
20.00
Tuesday, 12 / 12 / 2017
Peak discharge
= 154.40 cfs
Time to peak
= 12.00 hrs
Hyd. volume
= 426,759 cuft
Curve number
= 90
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.20 min
Distribution
= Type II
Shape factor
= 484
POND 2 POST -DEV
Hyd No 2 -- 100 Year
Q (cfs)
16000
14000
12000
100.00
40.00
20.00
000 - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Wet Detention Basin Worksheet
Basin ID Wet Pond #2 Required Designer Input=
Project Name Braebum
Project # FM26 420
Designer C Ludwg
Date 12/08/17
Rev 1
Basin Drainage Area Summary
Total Impervious Area 8 97 ac 406,248.36 sf
Total Pervious Area 7 91 ac 452,155.41 sf
Total Future Impervious Area 0 00 ac
Total Area, 19.71 ac 858,403.77 sf Perform Water Balance Calcs.
Percent BUA:l 4552%
Calculate The Design Volume
Design Rainfall 1 00 -in
Determine the Runoff Coefficient (Rv) for the 1 -in rainfall
R„=005+09x(1)
1 = 4552%
Rv = 0.46
Determine the Water Quality Volume (WQv)
WQ„ = Design Rainfall x Rv x Onsite Drainage Area
Design Rainfall is 1 Inch
Rv is 0.46
Drainage Area is 19 71 Acres
V(design) = 0 75 -ac -ft
32.881.67-cf
Calculate The Required Main Pool Volume
Equation 9e Main Pool Volume, V mp
VMP = 0.87 * HRT * DV
TS
Where: 0.87 = Factor to adjust for the volume In the forebay
VMP = Main pool volume, not including the forebay (cubic feet)
HRT = Required hydraulic residence time (14 days)
TS = Average time between storm events (5 days)
DV = Design volume (cubic feet)
Vmp = 80,099.75-cf

Calculate The Required Forebay Volume
V(forebay) = 20% of Vmp = 16,019.95-cf
Calculate the Permanent Pool Elevation from Proposed Contours with Forebay
Assumed Elev Of Permanent Pool 600.00 -ft
Elevation at Bottom of Littoral Shelf 599.00 -ft
Required Permanent Pool Volume 96,119 70-cf
Forebay Crest Elevation = 598.50 -ft
% Forebay = 16.62
Required PPE = 598.90 -ft
Proposed PPE = 600.00 -ft
Basin Detention Stage/Storage Above Permanent Pool Elevation
Elev
Contour Area
Basin Permanent Pool Stage/Storage
Accumul Vol
60000
41,721 87 sf
Elev
Forebay Area 1 Forebay Area 2
Main Bay Area
Total Area
Forebay Incr
Vol
Forebay
Accumulated
Vol
Main Bay Incr
Vol
Main Bay
Accumulated Vol
Total
Accumulated
Vol
59400
26127
83154 sf
15,414 18 sf
16,506 99 sf
0 00-cf
0 00-cf
0 OD-cf
0 00-cf
0 00-cf
59500
68684
1,217 53 sf
17,232 44 sf
19,136 81 sf
1,498 59-cf
1,498 59-cf
16,323 31-cf
16,323 31-cf
17,821 90-cf
59600
119836
1,666 03 sf
19,120 03 sf
21,986 42 sf
2,385 38-cf
3,883 97-cf
18,176 24-cf
34,499 55-cf
38,383 52-cf
59700
179763
2,183 03 sf
21,077 04 sf
25,057,70 sf
3,423 53-cf
7,307 50-cf
20,098 54-cf
54,598 08-cf
61,905 58 -Cf
59800
247763
2,762 52 sf
23,103 44 sf
28,343 59 sf
4,610 41-cf
11,917 90-cf
22,090 24-cf
76,688 32-cf
88,606 22-cf
59850
284288
3,076 46 sf
24,142 69 sf
30,062 03 sf
2,789 87-cf
14,707 77-cf
11,811 53-cf
88,499 85-cf
103,207 63-cf
59900
32,104 74 sf
32,104 74 sf
0 00.cf
222-21
14,061 86-cf
102,561 71-cf
102,561 71-cf
599 50
36,834 82 sf
36,834 82 sf
0 00-cf
0 00-cf
17,234 89-cf
119,796 60-cf
119,796 60-cf
60000
41,721 87 sf
41,721.87 sf
0 00-cf
0 00-cf
19,639 17-cf
139,435 77-cf
139,435 77-cf
% Forebay = 16.62
Required PPE = 598.90 -ft
Proposed PPE = 600.00 -ft
Basin Detention Stage/Storage Above Permanent Pool Elevation
Elev
Contour Area
Incr Vol
Accumul Vol
60000
41,721 87 sf
0 00 cf
119,796 60 c
601 00
44,729 54 sf
43,225 71 cf
163,022 31 c
60200
47,793 77 sf
46,261 66 cf
209,283 96 c
60300
50,914 53 sf
49,354 15 cf
258,63811 Cf
60400
54,091 84 sf
52,503 19 cf
311,141 30 c
60500
57,325 68 sf
55,708 76 cf
366,850 06 cf
6060
60,616 07 sf
58,970 88 cf
425,820 93 c
606 50
62,282 67 sf
30,724 69 cf
456,545 62 cf

Calculate the Average Depth of the Pond
Equation 2. Average depth when the shelf is not submerged or
the shelf is being included in the average depth calculation
VPP
Davg = A P P
Where: Davg = Average depth in feet
VPP = Volume of permanent pool (feet3)
APP = Area of permanent pool (feet')
Equation 3. Average depth when the shelf is submerged and
the shelf is being excluded Froin the average depth calculation
VPP—Vshelf
Davg =
Abottomofshelf
Where: Davg = Average depth in feet
VPP = Total volUrne of permanent pool (feet3)
Vshelf = Volume over the shelf only (feet3) — see below
Abottom of shelf = Area of wet pond at the bottom of the shelf (feet')
Vshelf = 0.5 * Depth,ax over shelf Perimeterperm pool * Widthsubmerged part ofshelf
Where: Dmax over shelf = Depth of water at the deep side of the shelf as
measured at permanent pool (feet)
Perimeterpermanent pool = Perimeter of permanent pool at tete bottom of the
shelf (feet)
Widthst,bmerged part of shelf = Width from the deep side to the dry side of the
shelf as measured at permanent pool (feet)
PPE =A599.00-ft
P P Perimeter =
Vpp =
App =
Bottom of Shelf Elev =
A(bottom of shelf) = I 32,104.74-sf
Vshelf) = 4,965.65-cf
Davg = 4.19 -ft

Determine The Orifice Size of the Riser Structure
1 -year, 24-hour Storm Pre -Development Runoff Volume =1 35,785.00-cf (See Hydraflow Hydrographs)
1 -year, 24-hour Storm Post -Development Runoff Volume = 118,242.00-cf (See Hydraflow Hydrographs)
Difference = 82,457.00-cf
Vpp = 139,435.77-cf
1 -year, 24-hour Storm Volume in Wet Pond 41 = 221,892.77-cf
1 -year, 24-hour Storm Elevation in Wet Pond #1 = 602 26 -ft
CA(29H)os = Q
C=
0.6
A=
7.07
in'
g =
32.2
ft/sec
H =
1.13
ft
Orifice Diameter =
3
in
Qout =
0.25
cfs
Drawdown Time =
3.80
days OK

Pond NO. 1 - WET POND 2 ABOVE PPE
Top of pond
-700
Elev. 606 50
-600
-500
-400
-300
WX1141
Sim
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
0 00 ' '
Stage (ft) •°�i-`�' '* `•� ` '-` ' `�` Bottom of pond
Elev 600 00
Section 25 -yr
NTS
10 -yr
100 -yr 2 -yr
50 -yr 1 -yr
Inflow hydrograph = 2 SCS Runoff - POND 2 POST -DEV
Project. Braeburn Pond 2.gpw Friday, 12 / 15 / 2017

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4 Friday, 12 / 15 / 2017
Pond No. 1 - WET POND 2 ABOVE PPE
Pond Data
Contours -User-defined contour areas Conic method used for volume calculation Begining Elevation = 600.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
000
60000
41,722
0
0
1 50
601 00
44,730
64,819
64,819
250
60200
47,794
46,249
111,068
350
60300
50,915
49,341
160,409
450
60400
54,092
52,490
212,899
550
60500
57,326
55,695
268,594
650
60600
60,616
58,957
327,551
700
60650
62,283
30,721
358,272
Culvert / Orifice Structures
Note Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control Weir risers checked for onfice conditions (ic) and submergence (s)
Weir Structures
Storage / Discharge Table
[A]
[Bl
[C]
[PrfRsr]
Elevation
[A]
[Bl
[C]
[D]
Rise (in)
= 2700
300
1200
000
Crest Len (ft)
= 2000
2000
000
000
Span (in)
= 4200
300
36.00
000
Crest EI. (ft)
= 60350
60450
000
000
No. Barrels
= 1
1
3
0
Weir Coeff.
= 333
333
333
333
Invert EI. (ft)
= 60000
60000
60250
000
Weir Type
= 1
Cipltl
---
---
Length (ft)
= 9300
050
050
000
Multi -Stage
= Yes
No
No
No
Slope (%)
= 050
000
000
n/a
--- --- --- 5486
550
268,594
60500
73 28 Ic
N -Value
= 013
013
013
n/a
650
327,551
60600
83 21 is
0 06 Ic
Orifice Coeff.
= 060
060
060
060
Exfil.(inlhr)
= 0 000 (by
Wet area)
0 05 is
8 95 Ic ---
Multi -Stage
= n/a
Yes
Yes
No
TW Elev. (ft)
= 000
Note Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control Weir risers checked for onfice conditions (ic) and submergence (s)
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
CIV C PrfRsr
Wr A
Wr B Wr C
Wr D Exfil User Total
ft
cuft
ft
cfs
cfs
cfs cfs
cfs
cfs cfs
cfs cfs cfs cfs
000
0
60000
000
000
000 ---
000
000 ---
--- --- - 0 000
1 50
64,819
601 00
0 22 is
0 22 is
000 ---
000
000 ---
--- --- --- 0 221
250
111,068
60200
0 32 is
0 32 is
000 ---
000
000 ---
--- --- --- 0 324
350
160,409
60300
11 17 Ic
0 34 Ic
10 83 Ic ---
000
000 ---
--- --- --- 11 17
450
212,899
60400
54 86 oc
0 17 Ic
31 14 Ic ---
2355
000 ---
--- --- --- 5486
550
268,594
60500
73 28 Ic
0.09 Ic
16 24 Ic ---
56 94 s
2355 ---
--- --- --- 96 82
650
327,551
60600
83 21 is
0 06 Ic
10 53 Ic ---
72 57 s
12235 ---
--- --- --- 20551
700
358,272
60650
87 56 is
0 05 is
8 95 Ic ---
78 55 s
18837 ---
--- --- --- 27592

Starmount Cove
CONCRETE ANCHOR BUOYANCY CALCULATIONS
WET POND #2
CS ##2
Unit wt of concrete (pcf) =
150
Ib/ft3
Unit wt of H2O =
62.4
Ib/ft3
TOP OF RISER ELEV =
603.50
ft
INV. OUT OF RISER ELEV. =
594.00
ft
INT. WIDTH OF RISER =
60
in
INT LENGTH OF RISER=
60
in
WALL THICK OF RISER=
6
in
BASE THICK. OF RISER =
6
in
VOL OF RISER=
3600
ft3
BUOYANT FORCE =
22464.0
lbs Vol. of Riser x Unit wt of H2O
VOL. CONC. IN RISER =
122.5 ft3
SINKING FORCE OF RISER =
10731 lbs
CONC. PAD THICKNESS =
36 in
CONC. PAD WIDTH/LENGTH =
8 ft
VOL OF CONC. PAD =
192.00 ft3
SINKING FORCE OF PAD =
16819.2 lbs
TOTAL SINKING FORCE =
27550.2 lbs
Factor of safety = SINKING FORCE
BUOYANT FORCE
F.S. = 1.23 OK
Vol. of Conc. x (Unit wt. of Conc. - Unit wt. of H2O)
L x W x H/ Pad Thickness
Vol. of Pad x (Unit wt. of Conc. - Unit wt. of H2O)
F.S. MUST BE GREATER THAN 1.10

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCADO Civil 3DO 2015 by Autodesk, Inc v10 4 Friday, 12 / 15 / 2017
Hyd. No. 3
WET POND 2 ROUTED
Hydrograph type
= Reservoir
Peak discharge
= 0.312 cfs
Storm frequency
= 1 yrs
Time to peak
= 24.13 hrs
Time interval
= 2 min
Hyd. volume
= 78,938 cuft
Inflow hyd. No.
= 2 - POND 2 POST -DEV
Max. Elevation
= 601.87 ft
Reservoir name
= WET POND 2 ABOVE PPE
Max. Storage
= 104,996 cuft
Q (cfs)
5000
4000
30.00
20.00
1000
WET POND 2 ROUTED
Hyd No. 3 -- 1 Year
10 20 30 40
Hyd No 3 Hyd No 2
50 60 70 80 90
=L --LSI Total storage used = 104,996 cuft
Q (cfs)
50.00
4000
30.00
2000
1000
1 0.00
100
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Friday, 12 / 15 / 2017
Hyd. No. 3
WET POND 2 ROUTED
Hydrograph type
= Reservoir
Peak discharge
= 0.620 cfs
Storm frequency
= 2 yrs
Time to peak
= 24.03 hrs
Time interval
= 2 min
Hyd. volume
= 93,056 cuft
Inflow hyd. No.
= 2 - POND 2 POST -DEV
Max. Elevation
= 602.53 ft
Reservoir name
= WET POND 2 ABOVE PPE
Max. Storage
= 137,042 cuft
Storage Indication method used
WET POND 2 ROUTED
Q (cfs) Hyd No 3 -- 2 Year Q (cfs)
6000 6000
5000 5000
4000 40.00
3000 30.00
20.00 2000
10.00 10.00
000 - 000
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No 3 Hyd No 2 ILL=Total storage used = 137,042 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCADS Civil 3D@ 2015 by Autodesk, Inc v10 4
Friday, 12 115 / 2017
Hyd. No. 3
WET POND 2 ROUTED
Hydrograph type
= Reservoir
Peak discharge
= 11.86 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.47 hrs
Time interval
= 2 min
Hyd. volume
= 209,593 cuft
Inflow hyd. No.
= 2 - POND 2 POST -DEV
Max. Elevation
= 603.02 ft
Reservoir name
= WET POND 2 ABOVE PPE
Max. Storage
= 161,468 cuft
Storage Indication method used
Q (cfs)
120.00
100.00
80.00
6000
4000
2000
0 00
WET POND 2 ROUTED
Hyd. No 3 -- 10 Year
Q (cfs)
120.00
10000
:1 1I
.I II
4000
2000
WWI
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No. 3 Hyd No. 2 EMTT_f Total storage used = 161,468 cult

Hyrdrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4 Friday, 12 / 15 / 2017
Hyd. No. 3
WET POND 2 ROUTED
Hydrograph type
= Reservoir
Peak discharge
= 32.07 cfs
Storm frequency
= 25 yrs
Time to peak
= 12.23 hrs
Time interval
= 2 min
Hyd. volume
= 277,908 cuft
Inflow hyd. No.
= 2 - POND 2 POST -DEV
Max. Elevation
= 603.53 ft
Reservoir name
= WET POND 2 ABOVE PPE
Max. Storage
= 187,884 cuft
Q (cfs)
140.00
120.00
100.00
01 10
40.00
WET POND 2 ROUTED
Hyd. No 3 -- 25 Year
0 00
0
Q (cfs)
14000
12000
10000
40.00
20.00
MAIN
4 8 12 16 20 24 28 32 36 40 44 48
Time (hrs)
Hyd No. 3 Hyd No. 2 =LI_Lli Total storage used = 187,884 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@ 2015 by Autodesk, Inc v10 4
Hyd. No. 3
WET POND 2 ROUTED
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 50 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 2 - POND 2 POST -DEV
Max. Elevation
Reservoir name
= WET POND 2 ABOVE PPE
Max. Storage
Storage Indication method used
Friday, 12 / 15 / 2017
= 50.31 cfs
= 12.20 hrs
= 329,610 cuft
= 603.87 ft
= 206,077 cuft
WET POND 2 ROUTED
Q (cfs) Hyd. No 3 -- 50 Year
160.00
14000
12000 - - ^- --�� -- - - —
100.00
80.00
6000
_-...__..._ _..-,......_ .. _Pry _ ..... �. 4000
2000
Q (cfs)
16000
14000
120.00
10000
4000
20.00
000 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No 3 Hyd No. 2 TZ1T(-(�I Total storage used = 206,077 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Friday, 12 / 15 / 2017
Hyd. No. 3
WET POND 2 ROUTED
Hydrograph type
= Reservoir
Peak discharge
= 57.92 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.20 hrs
Time interval
= 2 min
Hyd. volume
= 364,221 cuft
Inflow hyd. No.
= 2 - POND 2 POST -DEV
Max. Elevation
= 604.11 ft
Reservoir name
= WET POND 2 ABOVE PPE
Max. Storage
= 218,858 cuft
Storage Indication method used
WET POND 2 ROUTED
Q (cfs) Hyd. No 3 -- 100 Year Q (cfs)
16000 16000
- 140 00 14000
' 12000 120.00
100.00 10000
8000 80.00
60 00 6000
4000 40.00
2000 2000
000 - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No 3 Hyd No 2 !1111=1_-1-11 Total storage used = 218,858 cult

E.
Wet Pond 3
Pre -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Sod Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 3 TOC Pre-Dev
Braeburn - Pond 3 - TOC Calcs Pre -Development
12/14/2017
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location
Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 3 TOC Pre-Dev
1.
SHEET FLOW
SEGMENT ID
A
B
1
Surface description (table 3-1) ...
Woods -Light
Grass -Short
2
Manning's roughness coefficient, n (table 3-1)......
0.4
0.15
3
Flow length, L (total L <_ 300 ft) ft
34
66
4
Two-year 24-hour rainfall, P In
3 12
3.12
5
Land slope, s ........... . ......ft/ft
0.0300 1
0.018
6
Tt = 0.007 (nQA0 8 Compute Tt hr
0.13 +
012 0.25
P2^0 5s'04
2'.
SHALLOW CONCENTRATED FLOW
SEGMENT ID
C
7.
Surface description (paved or unpaved) .... .......
Unpaved
8
Flow length, L ft
361
9.
Watercourse slope, s ..ft/ft
00200
10
Average velocity, V (figure 3-1)
2.282
11
Tt = L Compute Tt hrl
004 +
0.04
3600 V
3. CHANNEL FLOW
�
SEGMENT ID
12
Channel type (Pipe or Open Channel)
13
Cross sectional flow area, a ....ft2
14
Wetted perimeter, pw ft
15
Hydraulic radius r = a/pw Computer... .. ft
16.
Channel slope, s ft/ft
17.
Manning's roughness coefficient, n .
18.
V = [1 49 r"(2/3) s^(1/2)] / n Compute V .. ... ...ft/s
19
Flow length, L .ft
20
Tt = L Compute Tt ... hr
+
0.00
3600 V
21
Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and
19)
Hr = 0 29
Min = 17.4
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Sod Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 3 TOC Pre-Dev
Braeburn - Pond 3 - TOC Calcs Pre -Development
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Pltone 803-802-2440 Fax [phone]
Runoff Curve Number and Runoff
Project Braebum
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: Present Developed Pond 3 CN Pre -Development
1. Runoff Curve Number
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
of
Tbl.
Fig.
Fig.
Group
and hydrologic condition)
2-2
2-3
2-4
Acres
CN x area
B
Woods, Good condition
55
0 000
000
(TaB)
B
Open space, Good condition (grass cover > 75%)
61
0.000
000
(TaB)
B
Dirt Roads (including right-of-way)
_
82
0 000
000
(TaB)
C
_ Woods, Good condition _
70
3 188
22315
(ScA)
C
Open space, Good condition (grass cover> 75%)
74
9 108
67399
(ScA)
C
Dirt Road_ s (including right-of-way)
87
0 000
000
(ScA)
C
Paved areas, streets, roofs, driveways, etc (excl ROW)
98
0.000
000
(ScA)
D
_ _ Woods, Good condition - - -
77
0 000
000
(CmB)
D
Open space, Good condition (grass cover> 75%)
- -(CmB)
80
0.000
0.00
D
Dirt Roads (including right-of-way)
89
0 000
000
(CmB)
D
Paved areas, streets, roofs, driveways, etc (excl.R_OW)
98
0 000
000
(CmB)
* Use only one CN source per line
Totals =
12 296
89714
CN (weighted) total product = 897 143 = 730
Use CN= 73
total area 122959
2. Runoff -
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall , P (24-hour) in
420
6.50
1030
Runoff, Q in
1 67
351
6.89
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Sod Conservation Service
US Department of Agriculture, June 1986
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
ESP Assocates, PA Pond 3 CN Pre -Development
PoBox 7030 Braeburn - Pond 3 - CN Calcs Pre-Dev
Charlotte NC 28241 12/14/2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D@ 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 3 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 12.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2 58 in
Storm duration
= 24 hrs
Q (cfs)
8.00
400
200
Tuesday, 12/12/2017
Peak discharge
= 7.670 cfs
Time to peak
= 12.10 hrs
Hyd. volume
= 27,299 cuft
Curve number
= 73
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 17.40 min
Distribution
= Type II
Shape factor
= 484
POND 3 PRE -DEV
Hyd. No 1 -- 1 Year
Q (cfs)
800
4.00
2.00
NOW
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 3 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 12.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.12 in
Storm duration
= 24 hrs
Tuesday, 12 / 12 12017
Peak discharge
= 12.45 cfs
Time to peak
= 12.10 hrs
Hyd. volume
= 41,614 cuft
Curve number
= 73
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 17.40 min
Distribution
= Type II
Shape factor
= 484
POND 3 PRE -DEV
Q (cfs) Hyd. No 1 -- 2 Year Q (cfs)
14 00
1200
1000
8.00
6.00
400
2.00
0 00
14 00
1200
10.00
8.00
600
4.00
2.00
000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

Hy►drograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 3 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 12.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 4.80 in
Storm duration
= 24 hrs
Q (cfs)
30.00
25.00
20.00
15.00
1000
500
Tuesday, 12 / 12 / 2017
Peak discharge
= 29.98 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 94,868 cuft
Curve number
= 73
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 17.40 min
Distribution
= Type II
Shape factor
= 484
POND 3 PRE -DEV
Hyd. No 1 -- 10 Year
Q (cfs)
30.00
25.00
2000
1500
10.00
5.00
000 - 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 3 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 25 yrs
Time interval
= 2 min
Drainage area
= 12.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.76 in
Storm duration
= 24 hrs
Q (cfs)
50.00
40.00
30.00
20.00
1000
0 00
Tuesday, 12/12/2017
Peak discharge
= 41.16 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 129,064 cuft
Curve number
= 73
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 17.40 min
Distribution
= Type II
Shape factor
= 484
POND 3 PRE -DEV
Hyd. No 1 -- 25 Year
Q (cfs)
50.00
4000
3000
2000
1000
KI MI
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCADG Civil 3D@ 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 1
POND 3 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 49.83 cfs
Storm frequency
= 50 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 155,867 cuft
Drainage area
= 12.300 ac
Curve number
= 73
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 17.40 min
Total precip.
= 6.48 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 3 PRE -DEV
Q (cfs)
Hyd. No 1 -- 50 Year
Q (cfs)
50.00
50.00
40.00
4000
-
30.00
30.00
2000
20.00
1000
1000
0.00
- 0.00
0 2 4 6 8 10
12 14 16 18 20 22
24 26
Hyd No. 1
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
POND 3 PRE -DEV
Hydrograph type = SCS Runoff Peak discharge
Storm frequency = 100 yrs Time to peak
Time interval = 2 min Hyd. volume
Drainage area = 12.300 ac Curve number
Basin Slope = 0.0% Hydraulic length
Tc method = User Time of conc. (Tc)
Total precip. = 6.96 in Distribution
Storm duration = 24 hrs Shape factor
Tuesday, 12 / 12 / 2017
= 55.71 cfs
= 12.07 hrs
= 174,168 cuft
= 73
= 0 ft
= 17.40 min
= Type II
= 484
Q (cfs)
POND 3 PRE -DEV
Hyd. No 1 -- 100 Year
Q (cfs)
60.00
6000
5000
50.00
4000
40.00
3000
3000
2000
20.00
1000
10.00
000 - 0 00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

F.
Wet Pond 3
Post -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Reference. Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
'NCDENR BMP Design Manual, July 2007
Wet Pond 3 TOC Post-Dev
Braeburn - Pond 3 - TOC Calcs Post -Development
12/14/2017
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 3 TOC Post-Dev
1.
SHEET. FLOW
w
SEGMENT ID
A
B
1
Surface description (table 3-1)
Grass -Short
Pavement
2
Manning's roughness coefficient, n (table 3-1) . ........
0.15
0.011
3.
Flow length, L (total L:5 300 ft) . ............. .. ft
80
20
4
Two-year 24-hour rainfall, P .in
3.12
3.12
5
Land slope, s ......... .. ..ft/ftl
0.0200 1
0.01
6.
Tt = 0 007 (nL)^0.8 Compute Tt hrI
0.14 +
0.01 015
P2^0.5 s^0 4
2.
SHALLOW,CONCENTRATED FLOW
SEGMENT ID
B
7.
Surface description (paved or unpaved)
Paved
8
Flow length, L .. ..... ............. ..ft
74
9.
Watercourse slope, s ft/ft
00200
10
Average velocity, V (figure 3-1) ...
1 2.875
11
Tt = L Compute Tt hrl
0 01 1 +
0.01
3600 V
3.
CHANNEL -FLOW -`
SEGMENT ID
C
12
Channel type (Pipe or Open Channel)
Pipe
13
Cross sectional flow area, a. . ft2
3 14
14.
Wetted perimeter, pw ....... ... .... ft
628
15
Hydraulic radius r= a/pw Compute r ft
050
16.
Channel slope, s ..ft/ft
0 005
17.
Manning's roughness coefficient, n .... ... ....... .
0 012
18.
V= [1.49 r^(2/3) s^(1/2)] / n Compute V ...ft/s
553
19.
Flow length, L ...ft
514
20
Tt = L Compute Tt hr
003 +
1 0031
3600 V
21
Watershed or subarea Tc or Tt (add Tt In steps 6, 11, and
19)
Hr=
Min = 11.4
Reference. Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
'NCDENR BMP Design Manual, July 2007
Wet Pond 3 TOC Post-Dev
Braeburn - Pond 3 - TOC Calcs Post -Development
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Phone [phone] Fax [phone]
Runoff Curve Number and Runoff
Project Braeburn
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: Present Develope Pond 3 Post -Development CN
1. Runoff Curve Number
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
Tbl.
Fig.
Fig.
of
Group
and hydrologic condition)
2-2
2-3
2-4
Acres
CN x area
B
Residential, 1/8 acre or less (town houses)
85
0 000
000
(TaB)
C
- Residential, 1/8 acre or less (town_ houses)
90
12 296
110663
(SCA)
D
Residential, 1/8 acre or less (town houses)
- -
92
0.000
000
(CmB)
* Use only one CN source per line
Totals =
12 296
110663
CN (weighted) total product = 1106 63 = 900
Use CN= 90
total area 122959
2. Runoff f
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall , P (24-hour) in
420
650
1030
Runoff, Q in
311
533
9.08
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
US Department of Agriculture, June 1986
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
ESP Assocates, PA Pond 3 Post -Development CN
PoBox 7030 Braeburn - Pond 3 - CN Calcs Post-Dev
Charlotte NC 28241 12/14/2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 3 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 28.31 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.00 hrs
Time interval
= 2 min
Hyd. volume
= 73,789 cuft
Drainage area
= 12.300 ac
Curve number
= 90
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 11.40 min
Total precip.
= 2.58 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
3000
25.00
2000
15.00
1000
5.00
an 11=11
POND 3 POST -DEV
Hyd. No. 2 -- 1 Year
Q (cfs)
3000
2500
20.00
1500
10.00
5.00
W I1
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 3 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 36.71 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.00 hrs
Time interval
= 2 min
Hyd. volume
= 96,446 cuft
Drainage area
= 12.300 ac
Curve number
= 90
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 11.40 min
Total precip.
= 3.12 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 3 POST -DEV
Q (cfs)
Hyd. No 2 -- 2 Year
Q (cfs)
4000
4000
3000
3000
20 00
20.00
10.00
1000
000
0.00
0 2 4 6 8 10
12 14 16 18 20 22
24 26
Time (hrs)
Hyd No. 2

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 3 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 62.95 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.00 hrs
Time interval
= 2 min
Hyd. volume
= 169,613 cuft
Drainage area
= 12.300 ac
Curve number
= 90
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 11.40 min
Total precip.
= 4.80 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 3 POST -DEV
Q (cfs) Hyd No 2 --10 Year
7000
60.00
5000
4000
30.00
20.00
1000
0 00 -
0
2 4 6
Hyd No 2
Q (cfs)
7000
5000
4000
3000
20.00
1000
rain
8 10 12 14 16 18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 3 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 77.85 cfs
Storm frequency
= 25 yrs
Time to peak
= 12.00 hrs
Time Interval
= 2 min
Hyd. volume
= 212,373 cuft
Drainage area
= 12.300 ac
Curve number
= 90
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 11.40 min
Total precip.
= 5.76 in
Distribution
= Type II
Storm duration
= 24 hrs,
Shape factor
= 484
POND 3 POST -DEV
Q (cfs) Hyd No 2 -- 25 Year
80.00
70.00
6000
- 50.00
4000
3000
20.00
100071�1-
Q (cfs)
8000
7000
5000
4000
3000
20.00
10.00
000 _— 0 00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 2
POND 3 POST -DEV
_ Hydrograph type
= SCS Runoff
Storm frequency
= 50 yrs
Time interval
= 2 min
Drainage area
= 12.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.48 in
Storm duration
= 24 hrs
Tuesday, 12 / 12 / 2017
Peak discharge
= 88.97 cfs
Time to peak
= 12.00 hrs
Hyd. volume
= 244,689 cuft
Curve number
= 90
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 11.40 min
Distribution
= Type II
Shape factor
= 484
POND 3 POST -DEV
Q (cfs) Hyd No. 2 -- 50 Year Q (cfs)
90 00
8000
7000
60.00
50.00
4000
30.00
20.00
1000
0 00
90 00
8000
70.00
60.00
50.00
40.00
3000
20.00
1000
0 00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc 00 4
Hyd. No. 2
Time to peak
POND 3 POST -DEV
Hyd. volume
_ Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 12.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.96 in
Storm duration
= 24 hrs
Q (Cfs)
Tuesday, 12 / 12 / 2017
Peak discharge
= 96.36 cfs
Time to peak
= 12.00 hrs
Hyd. volume
= 266,318 cuft
Curve number
= 90
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 11.40 min
Distribution
= Type II
Shape factor
= 484
POND 3 POST -DEV
Hyd. No 2 --100 Year Q (cfs)
100 00
i uu.uu
90.00
90.00
-
8000
_
_
8000
-_
—
_ _
_—--__-._
W
7000
7000
60.00
6000
- 50.00
50.00
4000
---- -
--
-----
--------
- —
--- -- -
-----_--
40.00
_---
—
-
-
-
----
3000 -
L
3000
20.00
----
--------------
----------------
2000
- -
—
- -
-----
1000
1000
0 2 4
Hyd No. 2
6 8 10 12 14 16 18 20 22 24 26
Time (hrs)

Wet Detention Basin Worksheet
Basin ID Wet Pond #3
Required Designer Input=_
Project Name Braebum
Project # iFM26 420
Designer C Ludwg
Date 12/08/17
Rev 1
Basin Drainage Area Summary
Total Impervious Area
5.04 ac
1 219,698.98 sf
Total Pervious Area
7.25 ac
315,909.41 sf
Total Future Impervious Area
0 00 ac
Total Area
12 30 ac
535,608.39 sf Perform Water Balance Calcs.
Percent BUA:J
41.02%
Calculate The Design Volume
Design Rainfall
1 00 -in
Determine the Runoff Coefficient (Rv) for the 1 -in rainfall
Rv = 0 05 + 0 9 x (1)
1 = 4102%
Rv = 042
Determine the Water Quality Volume (WQv)
WQ v = Design Rainfall x Rv x Onsite Drainage Area
Design Rainfall is 1 Inch
Rv is 0 42
Drainage Area is 12 3 Acres
WQv = (1 x 0 42 x 12 30)/12
V(design) = 0.43-ac-ff
18,709.13-cf
Calculate The Required Main Pool Volume
=rPool Volume, Vmp
VMP = 0.87 HRT DV
T,
Where 087 = Factor to adjust for the volume in the forebay
VrnP = Main pool volume, not including the forebay (cubic feet)
HRT = Required hydraulic residence time (14 days)
TS = Average time betvdeen storm events (5 days)
DV = Design volume (cubic feet)
Vmp = 45,575.43-cf

Calculate The Required Forebay Volume
V(forebay) = 20% of Vmp = 9,115.09-cf
Calculate the Permanent Pool Elevation from Proposed Contours with Forebay
Assumed Elev Of Permanent Pool
598.00 -ft
Elevation at Bottom of Littoral Shelf
597 50 -ft
Required Permanent Pool Volume
54,690.51-cf
Forebay Crest Elevation =
597.00 -ft
% Forebay = 17.73
Required PPE = 593.09 -ft
Proposed PPE = 598.00 -ft
Basin
Detention 5tagelstorage Above
Permanent PoolElevation
Basin Permanent Pool Stage/Storage
Elev
Contour Area
Incr Vol
Elev
Forebay Area
Main Bay Area
Total Area
Forebay Incr
Vol
Forebay
Accumulated
Vol
Main Bay Incr
Vol
Main Bay Total
Accumulated Vol Accumulated Vol
591 50
3,868 88 sf
29,882 93 sf
33,751 81 sf
0 00-cf
0 00-cf
0 00-cf
0 00-cf
0 00-cf
59200
4,27191 sf
30,948 45 sf
35,220 36 sf
2,035 20-cf
2,035 20-cf
15,207 85-cf
15,207 85-cf
17,243 04-cf
59300
5,129 87 sf
33,130 42 sf
38,260 29 sf
4,700 89-cf
6,736 09-cf
32,039 44-cf
47,247 28-cf
53,983.37-cf
59400
6,056 90 sf
35,380 50 sf
41,437 40 sf
5,593 39-cf
12,329 47-cf
34,255 46-cf
81,502 74-cf
93,832 21-cf
59500
1 7,053 01 sfl
37,698 69 sf 1
44,751 70 sfj
6,554 96-cf
18,884 43-cf
36,539 60-cf
1 118,042 34-cf
136,926 76-cf
59600
8,118 19 sf
40,084 98 sf
48,203 17 sf
7,585 60-cf
26,470 03-cf
38,891 84-cf
156,934 17-cf
183,404 20-cf
59700
9,252 46 sf
42,539 38 sf
51,791 84 sf
8,685 33-cf
35,155 35-cf
41,312 18-cf
198,246 35-cf
233,401 70-cf
59750
00 sf
53,908 56 sf
53,908 56 sfj
0 00-cf
1 35,155 35-cf
24,111 99-cf
222,358 34-cf
257,513 69-cf
59800
.00 sfj
58,760 76 sf
58,760 76 sf
0 00-cf
1 35,155 35-cf
28,167 33-cf
250,525 67-cf
285,681 02 -cf
% Forebay = 17.73
Required PPE = 593.09 -ft
Proposed PPE = 598.00 -ft
Basin
Detention 5tagelstorage Above
Permanent PoolElevation
Elev
Contour Area
Incr Vol
Accumul Vol
59800
58,760 76 sf
0 00 cf
285,681 02 cf
59850
63,770 18 sf
30,632.74 cf
316,313 75 cf
59900
65,303 51 sf
32,268 42 cf
348,582 18 cf
60000
68,412 80 sf
66,858 16 cf
415,440 33 cf
601 00
71,578 62 sf
69,995 71 cf
485,436 04 cf
602.00
74,800 98 sf
73,189 80 cf
558,625 84 cf
603.00
78,079 88 sf
76,440 43 cf
635,066 27 cf
604 00
81,415 35 sf
79,747 62 cf
714,813 89 cf
60500
84,807 35 sf
83,111 35 cf
797,925 24 cf

Calculate the Average Depth of the Pond
Equation 2. Average depth when the shelf is not submerged or
the shelf is being included in the average depth calculation
VPP
Davg = App
Where. Davg = Average depth In feet
VPP = Volume of permanent pool (feet3)
APP = Area of permanent pool (feet2)
Equation 3. Average depth when the shelf is submerged and
the shelf is being excluded from the average depth calculation
VPP—Vshel f
Davg = Ahottomofshelf
Where- Davg = Average depth in feet
VPP = Total volume of permanent pool (feet3)
Vshelf = Volume over the shelf only (feet3) — see below
Abottom of shelf = Area of wet pond at the bottom of the shelf (feet2)
Vsheif - 0.5 * Depthn,axover shelf " Perimeterpermpool * Widthsubmergedpart ofshelf
Where: Dmax over shelf = Depth of water at the deep side of the shelf as
measured at permanent pool (feet)
Perimeterpermanent pool = Perimeter of permanent pool at the bottom of the
shelf (feet)
Widthsubmergedpart ofshelf = Width from the deep side to the dry side of the
shelf as measured at permanent pool (feet)
PPE =
598.00 -ft
P P Perimeter =
986.16 -ft
Vpp =
285,681 02-cf
App =
58,760.76-sf
Bottom of Shelf Elev =
597.50 -ft
A(bottom of shelf) = 53� 908.56-sf
V(shelf) = 1,232 70-cf70-cf
Davg = 5.28 -ft

Determine The Orifice Size of the Riser Structure
1-year, 24-hour Storm Pre-Development Runoff Volume =
27,299.00-cf
(See Hydraflow Hydrographs)
1-year, 24-hour Storm Post-Development Runoff Volume =
73,789.00-cf
(See Hydraflow Hydrographs)
Difference =
46,490 00-cf
Vpp =
285,681.02-cf
1-year, 24-hour Storm Volume in Wet Pond #1 =
332,171.02-cf
1-year, 24-hour Storm Elevation in Wet Pond #1 =
598.75-ft
CA(2gH)o.s = Q
C =
0.6
A=
12.57 int
g =
32.2 ftlsec
H =
0.37 ft
Orifice Diameter=
4 in
Qout =
026 cfs
Drawdown Time =
210 days OK

Pond N o . 1 - POND 3 PPE=593 Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v104
-800
-700
-500
-400
-300
SleIf
- 1 00
—000
Stage (ft)
Top of pond --\
Elev 605 00
Elev 598 00
Section 25 -yr
NTS 10 -yr
100 -yr 2 -yr
50 -yr 1 -yr
Inflow hydrograph = 2 SCS Runoff - POND 3 POST -DEV
Project: Braeburn Pond 3 gpw Tuesday, 12 / 19 / 2017

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by
Autodesk, Inc. v10 4
Tuesday, 12 / 19 / 2017
Pond No. 1 - POND 3 PPE=598
Pond Data
Contours -User-defined contour areas
Conic method used for volume calculation Beglning
Elevation = 598 00 ft
Stage / Storage Table
Stage (ft) Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
000 59800
58,761
0
0
050 59850
63,770
30,621
30,621
100 59900
65,304
32,264
62,886
200 60000
68,413
66,845
129,731
300 601 00
71,579
69,983
199,714
400 60200
74,801
73,177
272,890
500 60300
78,080
76,427
349,317
600 60400
81,415
79,734
429,051
700 60500
84,807
83,097
512,148
Culvert / Orifice Structures
Weir Structures
[A]
[B] [C] [PrfRsr]
[A] [B]
[C] [D]
Rise (in) = 3600
400 000 000
Crest Len (ft)
= 16.00 2000
000 000
Span (in) = 3600
400 0.00 000
Crest EI. (ft)
= 60200 60300
000 000
No. Barrels = 1
1 0 0
Weir Coeff.
= 333 333
333 333
Invert EI. (ft) = 59800
59800 000 000
Weir Type
= 1 Clpltl
--- ---
Length (ft) = 5000
050 000 000
Multi -Stage
= Yes No
No No
Slope (%) = 050
000 000 n/a
N -Value = 013
013 013 n/a
Orifice Coeff. = 0.60
060 060 060
Exfil (in/hr)
= 0 000 (by Wet area)
Multi -Stage = n/a
Yes No No
TW Elev. (ft)
= 000
Note Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control Weir risers checked for onfice conditions (ic) and submergence (s)
Stage / Storage / Discharge
Table
Stage Storage Elevation
Clv A CIV B CIV
C PrfRsr Wr A
Wr B Wr C
Wr D Exfil User Total
ft cuft ft
cfs cfs cfs
cfs cfs
cfs cfs
cfs cfs cfs cfs
000 0 59800
000 000 ---
--- 000
0.00 ---
--- --- --- 0 000
050 30,621 59850
0 26 ic 0 24 ic ---
--- 000
000 --
--- --- --- 0 240
1 00 62,886 59900
0 37 is 0 37 ic ---
--- 0.00
000 ---
--- --- - 0 372
200 129,731 60000
0 55 ic 0 55 ic ---
--- 000
000 ---
--- --- 0 554
300 199,714 601 00
0 74 ic 0 69 ic ---
--- 000
000 ---
--- --- --- 0 690
400 272,890 60200
0 81 ic 0 81 ic ---
--- 000
000 ---
--- --- --- 0 806
500 349,317 60300
50 96 oc 0 36 ic ---
--- 50 59
s 0.00 ---
--- --- --- 50.96
600 429,051 60400
70 65 ic 0 18 ic ---
--- 70 46
s 6660 ---
--- --- --- 137.25
700 512,148 60500
79 24 ic 0.12 ic ---
--- 79 09
s 18837 ---
--- --- --- 26758

Starmount Cove
CONCRETE ANCHOR BUOYANCY CALCULATIONS
WET POND #3
CS #3
Unit wt of concrete (pcf) =
150
Ib/ft3
Unit wt. of H2O =
62.4
Ib/ft3
TOP OF RISER ELEV =
60200
ft
INV OUT OF RISER ELEV =
591 50
ft
INT WIDTH OF RISER=
48
in
INT LENGTH OF RISER=
48
in
WALL THICK OF RISER=
6
in
BASE THICK. OF RISER =
6
in
VOL. OF RISER=
2750
ft'
BUOYANT FORCE =
17160.0
lbs Vol of Riser x Unit wt. of H2O
VOL. CONC. IN RISER =
107 ft3
SINKING FORCE OF RISER =
9373.2 lbs
CONC. PAD THICKNESS =
24 in
CONC PAD WIDTH/LENGTH =
8 ft
VOL OF CONC PAD=
128.00 ft'
SINKING FORCE OF PAD =
11212.8 lbs
TOTAL SINKING FORCE =
20586.0 lbs
Factor of safety = SINKING FORCE
BUOYANT FORCE
Vol. of Conc. x (Unit wt. of Conc. - Unit wt. of H2O)
L x W x H/ Pad Thickness
Vol. of Pad x (Unit wt. of Conc. - Unit wt. of H2O)
F.S. = 1.20 OK F F.S. MUST BE GREATER THAN 1.10

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2015 by Autodesk, Inc v10 4 Tuesday, 12 / 19 / 2017
Hyd. No. 3
WET POND 3 PPE=598
Hydrograph type
= Reservoir
Peak discharge
= 0.358 cfs
Storm frequency
= 1 yrs
Time to peak
= 21.90 hrs
Time Interval
= 2 min
Hyd. volume
= 64,774 cuft
Inflow hyd. No.
= 2 - POND 3 POST -DEV
Max. Elevation
= 598.93 ft
Reservoir name
= POND 3 PPE=598
Max. Storage
= 58,611 cuft
Storage Indication method used
Q (cfs)
30.00
25.00
20.00
15.00
1000
500
0 00
WET POND 3 PPE=598
Hyd. No 3 --1 Year
Q (cfs)
3000
2500
20.00
15.00
1000
500
wi7iTil
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No 3 Hyd No 2 =IT] Total storage used = 58,611 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 19 / 2017
Hyd. No. 3
WET POND 3 PPE=598
Hydrograph type
= Reservoir
Peak discharge
= 0.420 cfs
Storm frequency
= 2 yrs
Time to peak
= 23.30 hrs
Time interval
= 2 min
Hyd. volume
= 84,154 cuft
Inflow hyd. No.
= 2 - POND 3 POST -DEV
Max. Elevation
= 599.23 ft
Reservoir name
= POND 3 PPE=598
Max. Storage
= 78,307 cuft
Storage Indication method used
Q (cfs)
4000
30.00
2000
10.00
WET POND 3 PPE=598
Hyd. No 3 -- 2 Year
Q (cfs)
4000
30.00
20.00
1000
000 "`' ' 0.00
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No 3 Hyd No. 2 1.171_1711 Total storage used = 78,307 cult

Hydr®graph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 3
WET POND 3 PPE=598
_.. Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 2 - POND 3 POST -DEV
Max. Elevation
Reservoir name
= POND 3 PPE=598
Max. Storage
Storage Indication method used
Q (cfs)
70.00
6000
5000
40.00
3000
2000
10.00
WET POND 3 PPE=598
Hyd No 3 --10 Year
Tuesday, 12 / 19 / 2017
= 0.583 cfs
= 24.07 hrs
= 134,996 cuft
= 600.20 ft
= 143,649 cult
Q (cfs)
70.00
.I 11
50.00
40.00
30.00
2000
1000
0.00
10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No 3 Hyd No 2 ;LE(= Total storage used = 143,649 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4 Tuesday, 12 / 19 / 2017
Hyd. No. 3
WET POND 3 PPE=598
Hydrograph type
= Reservoir
Peak discharge
= 0.660 cfs
Storm frequency
= 25 yrs
Time to peak
= 24.07 hrs
Time interval
= 2 min
Hyd. volume
= 159,079 cuft
Inflow hyd. No.
= 2 - POND 3 POST -DEV
Max. Elevation
= 600.75 ft
Reservoir name
= POND 3 PPE=598
Max. Storage
= 182,511 cuft
Storage Indication method used
I
I
Q (cfs)
WET POND 3 PPE=598
Hyd. No 3 -- 25 Year
Q (cfs)
80 00
80.00
70.00
7000
60.00
5000
6000
40.00
5000
30.00
4000
30.00
- —
---___------
---
--
2000
---
---
—
-----
—
20.00
1000
n nn
10.00
n nn
0 10
Hyd No 3
20 30 40
Hyd No 2
50 60 70 80 90
.I—
I LCl_Cll Total storage used = 182,511 cuft
100
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. N®. 3
WET POND 3 PPE=598
Hydrograph type = Reservoir Peak discharge
Storm frequency = 50 yrs Time to peak
Time interval = 2 min Hyd. volume
Inflow hyd. No. = 2 - POND 3 POST -DEV Max. Elevation
Reservoir name = POND 3 PPE=598 Max. Storage
Q (cfs)
9000
8000
70.00
6000
5000
' 40 00
30.00
2000
1000
000-�
WET POND 3 PPE=598
Hyd. No 3 -- 50 Year
0 10 20 30 40
Hyd No 3 Hyd No 2
Tuesday, 12 / 19 / 2017
= 0.712 cfs
= 24.07 hrs
= 175,641 cuft
= 601.17 ft
= 212,104 cuft
50 60 70 80 90
LECA Total storage used = 212,104 cuft
100vvV
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 3
WET POND 3 PPE=598
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 100 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 2 - POND 3 POST -DEV
Max. Elevation
Reservoir name
= POND 3 PPE=598
Max. Storage
Storage Indication method used
Q (cfs)
Tuesday, 12/19/2017
= 0.744 cfs
= 24.10 hrs
= 186,088 cuft
= 601.44 ft
= 232,005 cuft
WET POND 3 PPE=598
Hyd No 3 --100 Year Q (cfs)
100 00
100 00
90 00
90.00
8000
80.00
—_
—"
_—
7000
70.00
6000
6000
5000
5000
4000
4000
30.00
3000
20.00
2000
10.00
000
10.00
000
0
10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No. 3 Hyd No. 2 =I11 Total storage used = 232,005 cult

G.
Wet Pond 4
Pre -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 4 TOC Pre-Dev
Braeburn - Pond 4 - TOC Calcs Pre-Dev
12/14/2017
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 4 TOC Pre-Dev
1.
SHEET FLOW
SEGMENT ID
A
B
1
Surface description (table 3-1)
Grass -Short
Grass -Short
2
Manning's roughness coefficient, n (table 3-1) . ..
0.15
0.15
3
Flow length, L (total L <_ 300 ft) ..ft
57
43
4
Two-year 24-hour rainfall, P In
312 1
312
5
Land slope, s ... .ft/ft
'00175 1
0.0095
6
Tt = 0.007 (nL)^0 8 Compute Tt hr
0.11 +
Oil
022
P2"0 5 s"0 4
2.
SHALLOW CONCENTRATED FLOW
SEGMENT ID
B
C
7
Surface description (paved or unpaved)
Unpaved
Unpaved
8
Flow length, L ... ... ...... .. ............. ..ft
911
1192
9
Watercourse slope, s ft/ft
00170
0.0143
10
Average velocity, V (figure 3-1)
2 104
1 93
11.
Tt = L Compute Tt hrI
0.12 +
017
0.29
3600 V
3.
CHANNEL FLOW
SEGMENT ID
12
Channel type (Pipe or Open Channel)
13.
Cross sectional flow area, a .. ft2
14
Wetted perimeter, pw ft
15.
Hydraulic radius r = a/pw Compute r ..ft
16
Channel slope, s ... ft/ft
17
Manning's roughness coefficient, n .
18.
V = [1 49 r^(2/3) s^(1/2)] / n Compute V ... .. ...ft/s
19
Flow length, L ft
20
Tt = L Compute Tt hr
I +
I
1 0001
3600 V
21
Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and
19)
Hr =
0 51
Min =
3061
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 4 TOC Pre-Dev
Braeburn - Pond 4 - TOC Calcs Pre-Dev
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Phone [phone] Fax [phone]
Runoff Curve Number and Runoff
Project Braeburn
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: Present Developed Pond 4 CN Pre -Development
C Runoff Curve Ntimber
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
of
Tbl.
Fig.
Fig.
Group
and hydrologic condition)
2-2
2-3
2-4
Acres
CN x area
B
_ Woods, Good condition
55
2.527
13900
(TaB)
B
Open space, Good condition (grass cover> 75%)
4 — --
61
1.044
6371
(TaB)
B
oay)
_ _ __. Dirt Roads_ Including right -f w
-
82
0.238
1956
(TaB)
C
_ _ _ _ _ _ _ Woods,_Good condition
(ScA)
70
23 723'
166059
C
Open space, Good condition (grass cover > 75%) _
_
74
3 469
25671
(ScA)
C
_ _ DirtRoads (including right_of-way)
_ _ . _ _ -
87
0.397
3457
(ScA)
C
_ _Paved areas, streets,_roofs, driveways, etc (excl-ROW)
-- - - -
98
0.000
0.00
(ScA)
D
_ Woods, Good condition _ _ _ _
_ -
77
23 104
177903
(CmB)
D
__Open space, Good condition (grass cover > 75%) _ _ ,
_ _
80
8.668
69344
(CmB)
D
ing,right-of-w_� _
Dirt Roads cluday)
_ (in
_ _ _-
89
0.086
765
(CmB)
D
Paved areas, streets, roofs, driveways, etc (excl.ROW} _ _-
--- -- - - - - -
98
0 000
0 00
(CmB)--
* Use only one CN source per line
Totals=
63.258
465426
CN (weighted) total product = 4654 26 = 736
Use CN= 74
total area 632576
2, Runoff, z
_
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall, P (24-hour) in
4.20
650
1030
Runoff, Q in
174
3 61
703
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference. Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
US Department of Agriculture, June 1986
ESP Assocates, PA
PoBox 7030
Charlotte NC 28241
Rainfall, P, taken from
,NCDENR BMP Design Manual, July 20071
1
Pond 4 CN Pre-Deveiopment
Braeburn - Pond 4 - CN Calcs Pre-Dev
12/14/2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 4 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 63.260 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2.58 in
Storm duration
= 24 hrs
Q (cfs)
3500
3000
2500
20.00
1500
1000
500
Tuesday, 12/12/2017
Peak discharge
= 30.45 cfs
Time to peak
= 12.23 hrs
Hyd. volume
= 151,999 cuft
Curve number
= 74
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 30.60 min
Distribution
= Type II
Shape factor
= 484
POND 4 PRE -DEV
Hyd. No 1 -- 1 Year
Q (cfs)
3500
30.00
2500
2000
1500
10.00
5.00
000 - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
Time to peak
POND 4 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 63.260 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.12 in
Storm duration
= 24 hrs
Q (cfs)
50.00
40.00
30.00
20.00
1000
0 00 -L
0
Tuesday, 12/12/2017
Peak discharge
= 49.15 cfs
Time to peak
= 12.23 hrs
Hyd. volume
= 229,075 cuft
Curve number
= 74
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 30.60 min
Distribution
= Type II
Shape factor
= 484
POND 4 PRE -DEV
Hyd No. 1 -- 2 Year
Q (cfs)
50.00
4000
3000
2000
10.00
0.00
2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil MID 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 1
POND 4 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 117.11 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.23 hrs
Time interval
= 2 min
Hyd. volume
= 512,855 cuft
Drainage area
= 63.260 ac
Curve number
= 74
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 30.60 min
Total precip.
= 4.80 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
12000
100.00
8000
60.00
1
4000
2000
POND 4 PRE -DEV
Hyd. No. 1 -- 10 Year
Q (cfs)
12000
10000
40.00
2000
000 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 1
POND 4 PRE -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 159 75 cfs
Storm frequency
= 25 yrs
Time to peak
= 12.23 hrs
Time interval
= 2 min
Hyd. volume
= 693,819 cuft
Drainage area
= 63.260 ac
Curve number
= 74
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 30.60 min
Total precip.
= 5.76 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
16000
14000
12000
10000
:1 11
• 1 11
40.00
2000
0 00
0 2 4
Hyd No 1
i
POND 4 PRE -DEV
Hyd No. 1 -- 25 Year
Q (cfs)
16000
14000
12000
10000
:1 11
•1 11
4000
2000
000
8 10 12 14 16 18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 1
POND 4 PRE -DEV
Hydrograph type = SCS Runoff Peak discharge
Storm frequency = 50 yrs Time to peak
Time interval = 2 min Hyd. volume
Drainage area = 63.260 ac Curve number
Basin Slope = 0.0% Hydraulic length
Tc method = User Time of conc. (Tc)
Total precip. = 6.48 in Distribution
Storm duration = 24 hrs Shape factor
Tuesday, 12 / 12 / 2017
= 192.99 cfs
= 12.20 hrs
= 835,269 cuft
= 74
= 0 ft
= 30.60 min
= Type II
= 484
Q (cfs)
POND 4 PRE -DEV
Hyd No 1 -- 50 Year
Q (cfs)
210.00
21000
- A --
- l----
180.00
-�
-
180.00
-
150.00
15000
_
-
12000
12000
9000
90.00
6000
6000
_
30.00
3000
000 0 00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@ 2015 by Autodesk, Inc v10 4
I
Hyd. No. 1 '
Time to peak
POND 4 PRE -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 63.260 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.96 in
Storm duration
= 24 hrs
Q (cfs)
24000
210.00
180.00
15000
12000
9000
6000
3000
Tuesday, 12 / 12 / 2017
Peak discharge
= 215.54 cfs
Time to peak
= 12.20 hrs
Hyd. volume
= 931,695 cuft
Curve number
= 74
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 30.60 min
Distribution
= Type II
Shape factor
= 484
POND 4 PRE -DEV
Hyd No 1 -- 100 Year
Q (cfs)
24000
210.00
180.00
150.00
12000
3000
000 - - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)
-41
I
G-
Q (cfs)
24000
210.00
180.00
150.00
12000
3000
000 - - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 1 Time (hrs)

H.
Wet Pond 4
Post -Development

ESP Associates, P.A.
3475 Lakemont Blvd. Fort Mill, SC 29708 Phone [phone] Fax [phone]
Reference. Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 4 POST -DEV TOC
Braeburn - Pond 4 - TOC Calcs Post-Dev
12/14/2017
Time of Concentration (Tc) or Travel Time (Tt)
Project Braeburn
By CAL
Date 12/8/2017
Location
Indian Trail, Union County, NC
Checked MRR
Date 12/8/2017
Circle One: Present Developed Wet Pond 4 POST -DEV TOC
1.
SHEET FLOW
SEGMENT ID
A
1
Surface description (table 3-1)
Grass -Short
2
Manning's roughness coefficient, n (table 3-1)
0.15
3
Flow length, L (total L:5 300 ft) ft
100
4
Two-year 24-hour rainfall, P ...in
3 12
5.
Land slope, s ......... ..ft/ftl
00288
6
Tt = 0 007 (nL)^0 8 Compute Tt hrl
014 + 1
0.14
P210.5 s"0.4
2. SHALLOW CONCENTRATED FLOW
SEGMENT ID
B
C
7.
Surface description (paved or unpaved)
Unpaved
Unpaved
8
Flow length, L ft
136
170
9
Watercourse slope, s ft/ft
00288
0.0048
10.
Average velocity, V (figure 3-1) .....
2.738
1.12
11
Tt = L Compute Tt hrl
001 +
004
0.05
3600 V
3.
CHANNEL FLOW
SEGMENT ID
D
E
12
Channel type (Pipe or Open Channel)
Open Channel
Pipe
13
Cross sectional flow area, a .... ftZ
1200
3.14
14
Wetted perimeter, pw ft
1265
6.28
15
Hydraulic radius r= a/pw Compute r ft
095
050
16
Channel slope, s ft/ft
0 010
0 005
17.
Manning's roughness coefficient, n
0 040
0.012
18.
V = [1 49 r^(2/3) s^(1/2)] / n Compute V .... ft/s
360
553
19
Flow length, L ft
153
2497
20
Tt = L Compute Tt hr
001 1 + 1
0.13
1 0141
3600 V
21
Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19)
Hr=
L 033
Min =
19.8
Reference. Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
ESP Associates', PA
Po Box 7030
Charlotte NC 28241
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
Wet Pond 4 POST -DEV TOC
Braeburn - Pond 4 - TOC Calcs Post-Dev
12/14/2017

ESP Associates, P.A.
3475 Lakemont Blvd Fort Mill, SC 29708 Plione 803-802-2440 Fax [phone]
Runoff Curve Number and Runoff
Project Braeburn
By CAL
Date
12/8/2017
Location Indian Trail, Union County, NC
Checked MRR
Date
12/8/2017
Circle One: Present Develope Pond 4 Post -Development CPI
1: Runoff Curve Number -
Soil
Cover Description
CN*
Area
Product
Hydrologic
(cover type, treatment
Tbl.
Fig.
Fig.
of
Group
and hydrologic condition)
2-2
2-3
2-4
Acres
CN x area
B
Residential, 1/8 acre or less (town houses)
85
3.812
32399
(TaB)
C
Residential, 1/8 acre or less (town houses)
90
27 589
248302
(ScA)
D
Residential, 1/8 acre or less town houses
- ( _ _ __._ _ _ __
92
31 859
2931 01
(CmB)
* Use only one CN source per line
Totals =
63 260
573803
CN (weighted) total product = 5738 03 = 907
Use CN= 91
total area 63.2596
2. Runoff
Storm #1
Storm #2
Storm #3
Frequency yr
2
10
100
Rainfall , P (24-hour) in
420
650
1030
Runoff, Q in
321
545
920
(Use P and CN with table 3-11, fig 2-1,
and equation 3-14)
Reference Urban Hydrology for Small Watersheds
Technical Release 55, Soil Conservation Service
U S Department of Agriculture, June 1986
Rainfall, P, taken from
NCDENR BMP Design Manual, July 2007
ESP Assocates, PA Pond 4 Post -Development CN
PoBox 7030 Braeburn - Pond 4 - CN Calcs Post-Dev
Charlotte NC 28241 12/14/2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Hyd. No. 2
Time to peak
POND 4 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 63.260 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2.58 in
Storm duration
= 24 hrs
Q (cfs)
14000
120.00
100.00
80.00
4000
20.00
Tuesday, 12 / 12 / 2017
Peak discharge
= 122.95 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 386,550 cuft
Curve number
= 91
Hydraulic length
= 0 ft
Time of conic. (Tc)
= 19.80 min
Distribution
= Type II
Shape factor
= 484
POND 4 POST -DEV
Hyd. No. 2 -- 1 Year
Q (cfs)
140.00
12000
100.00
4000
20.00
0.00 1 1 1 1 1 1 1 -1 - 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 4 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 158.27 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 501,353 cuft
Drainage area
= 63.260 ac
Curve number
= 91
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 19.80 min
Total precip.
= 3.12 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 4 POST -DEV
Q (cfs) Hyd No. 2 -- 2 Year
160.00
140.00
120.00
10000 - . — .- -- — --- -- -----
80 00 -- ------ --
60 00
4000
2000 —
Q (cfs)
16000
140.00
120.00
10000
4000
2000
0.00 - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. N®. 2
POND 4 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 268.13 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 869,883 cuft
Drainage area
= 63.260 ac
Curve number
= 91
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 19.80 min
Total precip.
= 4.80 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
28000
24000
160.00
12000
8000
4000
POND 4 POST -DEV
Hyd No 2 -- 10 Year
Q (cfs)
280.00
240.00
20000
160.00
120.00
40.00
0.00 —I i i i i r— —, '— 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D@ 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 2
POND 4 POST -DEV
Hydrograph type
= SCS Runoff
Peak discharge
= 330.44 cfs
Storm frequency
= 25 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 1,084,444 cuft
Drainage area
= 63.260 ac
Curve number
= 91
Basin Slope
= 0.0%
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 19.80 min
Total precip.
= 5.76 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
POND 4 POST -DEV
Q (cfs) Hyd No. 2 -- 25 Year
35000
300.00
25000
200.00
15000
10000
5000
Q (cfs)
350.00
30000
25000
200.00
15000
10000
50.00
0.00 - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCADO Civil 3DO 2015 by Autodesk, Inc v10 4
Hyd. No. 2
Time to peak
POND 4 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 50 yrs
Time interval
= 2 min
Drainage area
= 63.260 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.48 in
Storm duration
= 24 hrs
Q (cfs
400.00
35000
300.00
25000
20000
15000
10000
5000
Tuesday, 12/12/2017
Peak discharge
= 376.93 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 1,246,385 cuft
Curve number
= 91
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 19.80 min
Distribution
= Type II
Shape factor
= 484
POND 4 POST -DEV
Hyd No 2 -- 50 Year
Q (cfs)
40000
35000
30000
25000
200.00
15000
10000
5000
000 - - 000
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No 2 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D@ 2015 by Autodesk, Inc v10
Hyd. No. 2
Time to peak
POND 4 POST -DEV
Hyd. volume
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 63.260 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.96 in
Storm duration
= 24 hrs
Tuesday, 12 / 12 / 2017
Peak discharge
= 407.81 cfs
Time to peak
= 12.07 hrs
Hyd. volume
= 1,354,695 cuft
Curve number
= 91
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 19.80 min
Distribution
= Type II
Shape factor
= 484
POND 4 POST -DEV
Q (cfs) Hyd. No. 2 -- 100 Year Q (cfs)
42000 42000
36000 36000
30000 30000
240.00 240.00
18000 18000
12000 120.00
6000 6000
000 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

Wet Detention Basin Worksheet
Basin ID Wet Pond #4
Required Designer Input=
Project Name Braebum
Project # FM26 420
Designer C Ludwig
Date 12/08/17
Rev 1
Basin Drainage Area Summary
Total Impervious Area
28 21 ac
1,228,786.66 sf
Total Pervious Area
35 05 ac
1,526,809.86 sf
Total Future Impervious Area
0 00 ac
TotalArea•
63.26 ac
2,755,596.52 sf
Percent BUA
44.59
Calculate The Design Volume
Design Rainfall 1,00 -in
Determine the Runoff Coefficient (Rv) for the 1 -in rainfall
R„=005+09x(1)
1= 4459%
Rv = 0.45
Determine the Water Quality Volume (WQv)
WQ , = Design Rainfall x Rv x Onsite Drainage Area
Design Rainfall is 1 Inch
Rv is 0 45
Drainage Area is 63 26 Acres
V(design) = 2.36 -ac -ft
103,640.65-cf
Calculate The Required Main Pool Volume
Equation 1: Main Pool Volume, VmP
VMp = 0.87 * HRT * DV
T,
Where: 0.87 = Factor to adjust for the volume in the forebay
VMP = Main pool volume, not Including the forebay (cubic feet)
HRT = Required hydraulic residence time (14 days)
TS = Average time between storm events (5 days)
DV = Design volume (cubic feet)
VMP = 252,466.63-cf

Calculate The Required Forebay Volume
V(forebay) = 20% of Vmp = 50,493.73-cf
Calculate the Permanent Pool Elevation from Proposed Contours with Forebay
Assumed Elev Of Permanent Pool
600.00 -ft
Elevation at Bottom of Littoral Shelf
600.00 -ft
Required Permanent Pool Volume
302,962.35-cf
Forebay Crest Elevation =
599.50 -ft
% Forebay = 16.41
Required PPE = 596 41 -ft
Proposed PPE = 600 00 -ft
Basin Detention Stage/Storage Above Permanent Pool Elevation
Elev
Contour Area
Basin Permanent Pool Stage/Storage
Accumul Vol
60000
123,918 23 sf
Elev
Forebay Area 1 Forebay Area 2
Main Bay Area
Total Area
Forebay Incr
Vol
Forebay
Accumulated
Vol
Main Bay Incr
Vol
Main Bay
Accumulated Vol
Total
Accumulated
Vol
59300
735840
925 97 sf
72,523 42 sf
80,807 79 sf
0 00-cf
0 00-cf
0 00-cf
0 00-cf
0 00-cf
59400
841491
1,420 37 sf
76,413 76 sf
86,249 04 sf
9,059 83-cf
9,059 83-cf
74,468 59-cf
74,468 59-cf
83,528 42-cf
59500
9538.13
1,983 37 sf
80,377 73 sf
91,899 23 sf
10,678 39-cf
19,738 22-cf
78,395 75-cf
152,864 34-cf
172,602 55-cf
59600
1072736
2,604 65 sf
84,415 50 sf
97,747 51 sf
12,426 76-cf
32,164 97-cf
82,396 62-cf
235,260 95-cf
267,425 92-cf
59700
1198261
3,284 21 sf 1
88,527 08 sf
103,793 90 sf
14,299 42-cf
46,464 39-cf
86,471 29-cf
321,732 24-cf
368,196.63-cf
59800
1330388
4,022 04 sf
92,712 47 sf
110,038 39 sf
16,296 37-cf
62,760 76-cf
90,619 78-cf
412,352 02-cf
475,112 77-cf
59900
14691 17
4,818 15 sf
96,971 67 sf
116,480 99 sf
18,417 62-cf
81,178 38-cf
94,842 07-cf
507,194 09-cf
588,372 46-cf
59950
1542016
5,434 52 sf
99,128 86 sf
119,983 54 sf
10,091 00-cf
91,269 38-cf
49,025 13-cf
556,219 22-cf
647,488 59-cf
60000
000
00 sf
123,918 23 sf
123,918 23 sf
0 00-cf
91,269 38-cf
55,761 77-cf
611,980 99-cf
703,250 37-cf
% Forebay = 16.41
Required PPE = 596 41 -ft
Proposed PPE = 600 00 -ft
Basin Detention Stage/Storage Above Permanent Pool Elevation
Elev
Contour Area
Incr Vol
Accumul Vol
60000
123,918 23 sf
0 00 cf
703,250 37 c
60050
132,577.47 sf
64,123 93 cf
767,374 29 cf
601.00
141,393 33 sf
68,492 70 cf
835,865 99 c
60200
146,758 22 sf
144,075 78 cf
979,942 77 c
60300
152,179 63 sf
149,468 93 cf
1,129,411 69 cf
60400
157,657 55 sf
154,918 59 cf
1,284,330 28 cf
60500
163,191 99 sf
160,424 77 cf
1,444,755 05 cf
60600
168,782 94 sf
165,987 47 cf
1,610,742 52 c
60700
174,432.21 sf
171,607 58 cf
1,782,350 09 c
60800
180,136 57 sf
177,284 39 cf
1,959,634 48 cf
60850
183,009 96 sf
90,786 63 cf
2,050,421 11 c

Calculate the Average Depth of the Pond
Equation 2. Average depth when the shelf is not submerged or
the shelf is being included in the average depth calculation
VPP
Davit = APP
Where Davg = Average depth In feet
VPP = Volume of permanent pool (feet3)
APP = Area of permanent pool (feet')
Equation 3. .overage depth when the shelf is submerged and
the shelf is being excluded from the average depth calculation
VPP—Vshelf
Davg = Ahottomofshelf
Where- Dati,q = Average depth in feet
VPP = Total volume of permanent pool (feet3)
Vshelf = Volume over the shelf only (feet3) — see below
Abottom of shelf = Area of wet pond at the bottom of the shelf (feetz)
Vshelf = 0.5 * Depth,,,axover shelf Perimeterpern,pool * Widthsubmergedpart ofshelf
Where: Dmatiover shelf = Depth of water at the deep side of the shelf as
measured at permanent pool (feet)
Perimeterpermanent pool = Perimeter of permanent pool at the bottom of the
shelf (feet)
Widthsabmerged part of shelf = Width from the deep side to the dry side of the
shelf as measured at permanent pool (feet)
PPE =W600.00-ft
P P Perimeter=
Vpp =
App =
Bottom of Shelf Elev =
A(bottom of shelf) = 123,918.23-sf
Vshelf) = 0.00-cf
Davg = 5 68 -ft

Determine The Orifice Size of the Riser Structure
1 -year, 24-hour Storm Pre -Development Runoff Volume =1 151,999.00-cf (See Hydraflow Hydrographs)
1 -year, 24-hour Storm Post -Development Runoff Volume= 386,550.00-cf (See Hydraflow Hydrographs)
Difference = 234,551.00-cf
Vpp = 703,250.37-cf
1 -year, 24-hour Storm Volume in Wet Pond 01 = 937,801.37-cf
1 -year, 24-hour Storm Elevation in Wet Pond #1 = .01.71 ft
CA(2gH)a.s = Q
C =
0.6
A=
28.27
in'
9 =
32.2
ftfsec
H=
085
ft
Orifice Diameter=
6
in
Qout =
0.87
cfs
Drawdown Time =
3.11
days OK

Pond No. 1 - WET POND 4 PPE=600
M011161
-800
-600
-400
IM1111
—000
Stage (ft)
Hydraflow Hydrographs Extension for AutoCAD@) Civil 3D@) 2015 by Autodesk, Inc v10 4
Top of pond —\
Elev 608 50
Elev 600 00
25 -yr
Section 10 -yr
NTS
100 -yr 2 -yr
50 -yr 1 -yr
Inflow hydrograph = 2 SCS Runoff - POND 4 POST -DEV
Project Braeburn Pond 4.gpw Thursday, 12 / 14 / 2017

Pond Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Pond No. 1 - WET POND 4
PPE=600
Pond Data
Contours -User-defined contour areas Conic method used for volume calculation Beglning
Elevation = 600 00 ft
Stage / Storage Table
Stage (ft) Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
000 60000
123,918
0
0
050 601 00
132,577
64,105
64,105
1.00 601 00
141,393
68,474
132,579
200 60200
146,758
144,053
276,632
300 60300
152,180
149,446
426,078
400 60400
157,658
154,895
580,973
500 60500
163,192
160,401
741,374
600 60600
168,783
165,963
907,337
700 60700
174,432
171,582
1,078,919
800 60800
180,137
177,259
1,256,178
850 60850
183,010
90,777
1,346,955
Culvert/ Orifice Structures
Weir Structures
[A]
[B] [C] [PrfRsr]
[A] [B]
[C] [D]
Rise (in) = 4200
600 1200 000
Crest Len (ft)
= 2000 2000
000 000
Span (in) = 4200
600 36.00 000
Crest EI. (ft)
= 60500 60650
000 000
No. Barrels = 1
1 3 0
Weir Coeff.
= 333 333
333 333
Invert EI. (ft) = 600.00
600.00 60300 0.00
Weir Type
= 1 CIPltl
--- ---
Length (ft) = 11700
050 050 000
Multi -Stage
= Yes No
No No
Slope (%) = 050
000 000 n/a
N -Value = 013
013 013 n/a
Orifice Coeff. = 060
060 060 0.60
Exfil.(in/hr)
= 0 000 (by Wet area)
Multi -Stage = n/a
Yes Yes No
TW Elev. (ft)
= 000
Note Culvert/Onfice outflows are analyzed under inlet (ic) and outlet (oc) control Weir risers checked for onfice conditions (ic) and submergence (s)
Stage / Storage / Discharge Table
Stage Storage Elevation
Civ A CIV B
CIV C
PrfRsr Wr A
Wr B Wr C
Wr D Exfil User
Total
ft cuft ft
cfs cfs
cfs
cfs cfs
cfs cfs
cfs cfs cfs
cfs
000 0 60000
000 000
000
--- 000
000 ---
--- --- ---
0 000
050 64,105 601 00
0 82 is 0 79 is
000
--- 000
000 ---
--- --- ---
0 789
1 00 132,579 601 00
0 91 Ic 0 77 is
000
--- 000
000 ---
--- --- ---
0 775
200 276,632 60200
1.20 is 1 20 ic
0 00
--- 000
000 ---
--- --- ---
1204
300 426,078 60300
1 53 is 1 52 is
000
--- 000
000 ---
--- --- ---
1 519
400 580,973 60400
31 86 oc 1 16 ic
30 64 ic
--- 000
000 ---
--- --- ---
31 80
500 741,374 60500
48 77 oc 1 04 is
47 73 ic
--- 000
000 ---
--- --- ---
4877
600 907,337 60600
84 66 oc 0 64 is
29 30 ic
--- 5471
s 000 ---
--- --- ---
8465
700 1,078,919 60700
103 31 oc 0 39 ic
17 98 ic
--- 84 93
s 2355 ---
--- --- ---
12685
800 1,256,178 60800
115 01 IC 0 27 ic
12 60 is
--- 102 10 s 12235 ---
--- --- ---
237.33
850 1,346,955 60850
119 78 ic 0 24 is
10 91 ic
--- 108 58 s 18837 ---
--- --- ---
308.10

Starmount Cove
CONCRETE ANCHOR BUOYANCY CALCULATIONS
WET POND #4
CS #4
Unit wt of concrete (pcf) =
150
Ib/ft3
Unit wt of H2O =
62.4
Ib/ft3
TOP OF RISER ELEV. =
60500
ft
INV. OUT OF RISER ELEV =
59300
ft
INT WIDTH OF RISER =
60
in
INT. LENGTH OF RISER =
60
in
WALL THICK. OF RISER =
6
in
BASE THICK OF RISER=
6
in
VOL OF RISER=
4500
ft3
BUOYANT FORCE =
28080.0
lbs Vol. of Riser x Unit wt of H2O
VOL. CONC. IN RISER =
150 ft3
SINKING FORCE OF RISER =
13140 lbs
CONC PAD THICKNESS =
42 in
CONC. PAD WIDTH/LENGTH =
8 ft
VOL OF CONC PAD=
224.00 ft3
SINKING FORCE OF PAD =
19622.4 lbs
TOTAL SINKING FORCE =
32762.4 lbs
Factor of safety = SINKING FORCE
BUOYANT FORCE
Vol. of Conc. x (Unit wt. of Conc. - Unit wt. of H2O)
L x W x H/ Pad Thickness
Vol. of Pad x (Unit wt. of Conc. - Unit wt. of H2O)
F.S. = 1.17 OK F.S. MUST BE GREATER THAN 1.10

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. N®. 3
WET POND 4 PPE=600
Hydrograph type
= Reservoir
Peak discharge
= 1.322 cfs
Storm frequency
= 1 yrs
Time to peak
= 24.13 hrs
Time interval
= 2 min
Hyd. volume
= 318,041 cuft
Inflow hyd. No.
= 2 - POND 4 POST -DEV
Max. Elevation
= 602.35 ft
Reservoir name
= WET POND 4 PPE=600
Max. Storage
= 329,619 cuft
Storage Indication method used
WET POND 4 PPE=600
Q (Cfs) Hyd No 3 -- 1 Year
14000
120.00
10000
80.00
6000
4000
2000
0 00
0
10 20 30 40 50 60 70 80 90 100
Time (hrs)
Hyd No 3 Hyd No 2 TJ] LTA Total storage used = 329,619 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4 Tuesday, 12 / 12 / 2017
Hyd. No. 3
WET POND 4 PPE=600
Hydrograph type
= Reservoir
Peak discharge
= 1.873 cfs
Storm frequency
= 2 yrs
Time to peak
= 24.07 hrs
Time interval
= 2 min
Hyd. volume
= 368,858 cuft
Inflow hyd. No.
= 2 - POND 4 POST -DEV
Max. Elevation
= 603.04 ft
Reservoir name
= WET POND 4 PPE=600
Max. Storage
= 431,807 cuft
Storage Indication method used
WET POND 4 PPE=600
Q (cfs) Hyd. No. 3 -- 2 Year
16000
14000 -- -- -- - - --------------- - —
12000 --- — - - - ---- - - --- ------
100 00 -------- -- --------- --- - -- ------ - ------ -- -
80.00406000
00
20.00
n nn
0
10 20 30 40
Hyd No 3 Hyd No 2
50 60 70 80 90
ZT_= Total storage used = 431,807 cuft
100vvV
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@ 2015 by Autodesk, Inc v10 4
Hyd. No. 3
WET POND 4 PPE=600
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 2 - POND 4 POST -DEV
Max. Elevation
Reservoir name
= WET POND 4 PPE=600
Max. Storage
Storage Indication method used
I
Q (cfs)
28000
240.00
20000
160.00
12000
:1 11
4000
WET POND 4 PPE=600
Hyd. No. 3 -- 10 Year
Tuesday, 12 / 12 / 2017
= 22.84 cfs
= 12.90 hrs
= 730,949 cuft
= 603.79 ft
= 548,539 cuft
10 20 30 40
Hyd No. 3 Hyd No 2
Q (cfs)
28000
24000
20000
160.00
120.00
:1 11
4000
000
50 60 70 80 90 100
Time (hrs)
FF Total storage used = 548,539 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2015 by Autodesk, Inc. v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 3
WET POND 4 PPE=600
Hydrograph type
= Reservoir
Peak discharge
= 41.71 cfs
Storm frequency
= 25 yrs
Time to peak
= 12.60 hrs
Time interval
= 2 min
Hyd. volume
= 944,413 cuft
Inflow hyd. No.
= 2 - POND 4 POST -DEV
Max. Elevation
= 604.44 ft
Reservoir name
= WET POND 4 PPE=600
Max. Storage
= 651,654 cuft
Storage Indication method used
Q (cfs)
350.00
300.00
25000
20000
150.00
10000
5000
0.00 -'
0 10 20
Hyd No 3
WET POND 4 PPE=600
Hyd No 3 -- 25 Year
Q (Cfs)
350.00
300.00
250.00
200.00
MR1614It
100.00
5000
-' ' 000
30 40 50 60 70 80 90 100
Time (hrs)
Hyd No. 2 LET= Total storage used = 651,654 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD@ Civil 3D® 2015 by Autodesk, Inc v10 4
Tuesday, 12 / 12 / 2017
Hyd. No. 3
WET POND 4 PPE=600
Hydrograph type
= Reservoir Peak discharge
= 49.11 cfs
Storm frequency
= 50 yrs Time to peak
= 12.57 hrs
Time interval
= 2 min Hyd. volume
= 1,105,698 cuft
Inflow hyd. No.
= 2 - POND 4 POST -DEV Max. Elevation
= 605.01 ft
Reservoir name
= WET POND 4 PPE=600 Max. Storage
= 743,803 cuft
Storage Indication method used
WET POND 4 PPE=600
Q (cfs)
Hyd. No 3 -- 50 Year
400 00
350.00
300 00
25000
200.00
15000
10000
1000
0.00 - 000
0 10
Hyd No 3
20 30 40
Hyd No. 2
50 60 70 80 90
E� Total storage used = 743,803 cuft
100
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc v10 4 Tuesday, 12 / 12 / 2017
Hyd. N®. 3
WET POND 4 PPE=600
Hydrograph type
= Reservoir
Peak discharge
= 60.80 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.50 hrs
Time interval
= 2 min
Hyd. volume
= 1,213,617 cuft
Inflow hyd. No.
= 2 - POND 4 POST -DEV
Max. Elevation
= 605.36 ft
Reservoir name
= WET POND 4 PPE=600
Max Storage
= 801,392 cuft
Storage Indication method used
Q (cfs)
42000
36000
300.00
240.00
180.00
120.00
• 1 11
(I f)o —!— — —
WET POND 4 PPE=600
Hyd No. 3 -- 100 Year
10 20 30 40
Hyd No 3 Hyd No 2
Q (cfs)
42000
36000
300.00
24000
18000
120.00
•1 11
0.00
50 60 70 80 90 100
Time (hrs)
fLCC 3 Total storage used = 801,392 cult

I.
Summary

f
SUMMARY TABLE POND 1
SUMMARY TABLE
STORM
PRE -DEV 1 -YEAR
STORM FLOW
POND
DA (AC)
PRE -TOC PRE -CN
POST -TOC
POST -CN
1
13.29
22.2 70
16.8
89
2
19.71
33 70
10.2
90
3
12.30
17.4 73
11.4
90
4
63.26
30.6 74
19.8
91
SUMMARY TABLE POND 1
STORM
PRE -DEV 1 -YEAR
STORM FLOW
ROUTED 1 -YEAR
STORM FLOW
DIFFERENCE
1 -YEAR
5.51
0.25
-526
2 -YEAR
9.81
0.29
-952
10 -YEAR
26.15
0.59
-25.56
25 -YEAR
36.72
2.33
-34.39
50 -YEAR
45.1
4.92
-40.18
100 -YEAR
50.82
778
-43.04
SUMMARY TABLE POND 2
STORM
PRE -DEV 1 -YEAR
STORM FLOW
ROUTED 1 -YEAR
STORM FLOW
DIFFERENCE
1 -YEAR
6.33
0.31
-6.02
2 -YEAR
11.30
0.62
-10.68
10 -YEAR
30.67
11.86
-18.81
25 -YEAR
43.23
32.07
-11.16
50 -YEAR
53.07
5031
-2.76
100 -YEAR
59.78
5792
-1.86
SUMMARY TABLE POND 3
STORM
PRE -DEV 1 -YEAR
STORM FLOW
ROUTED 1 -YEAR
STORM FLOW
DIFFERENCE
1 -YEAR
7.67
0.36
-7.32
2 -YEAR
1245
0.42
-12.03
10 -YEAR
29.98
0.58
-29.40
25 -YEAR
41.16
0.66
-40.50
50 -YEAR
49.83
0.71
-49.12
100 -YEAR
55.71
0 742
-54.97
SUMMARY TABLE POND 4
STORM
PRE -DEV 1 -YEAR
STORM FLOW
ROUTED 1 -YEAR
STORM FLOW
DIFFERENCE
1 -YEAR
30.45
1.32
-29.13
2 -YEAR
49.15
1.87
-47.28
10 -YEAR
117.11
2284
-94.27
25 -YEAR
159.75
41.71
-118.04
50 -YEAR
192.99
49.11
-143 88
100 -YEAR
215.54
60.8
-154.74

8.
Impervious Area Calculations
r
v

Pond 1 Impervious Areas
Buildings Roads and Curb Driveways
Sidewalks
Tota I
Impervious
Area
Drainage Area % Impervious
149,360.34 sf 58,075.03 sf 17,302.32 sf
17,807.97 sf
242,545.66 sf
578,715.60 sf 4191%
3.43 ac 133 ac 0 40 ac
0.41 ac
5.57 ac
13.29 ac 4191%
Pond 2 Impervious Areas
Buildings
Roads and Curb
Driveways Sidewalks
Total
Impervious Drainage Area
Area
% Impervious
220,160.47 sf
115,631.28 sf
34,105.68 sf 36,350.93 sf
406,248 36 sf 858,405.62 sf
4733%
5.05 ac
2 65 ac
0.78 ac 0 83 ac
9.33 ac 19 71 ac
47.33%
Pond 3 Impervious Areas
Buildings
Roads and Curb
Driveways
Sidewalks
Tota I
Impervious Drainage Area
Area
% Impervious
133,901 37 sf
46,136.31 sf
23,940.00 sf
15,721.27 sf
219,698 95 sf 535,608.39 sf
4102%
3.07 ac
1.06 ac
0.55 ac
0.36 ac
5.04 ac 12.30 ac
4102
Pond 4 Impervious Areas
Buildings
Roads and Curb Driveways
Sidewalks
Amenity Total Impervious
Center Area
Drainage Area % Impervious
631,026 91 sf
288,233.04 sf 108,108.00 sf
95,193.74 sf
106,224.97 sf 1,228,786 66 sf
2,755,596.52 sf 4459%
14.49 ac
6.62 ac 2.48 ac
2.19 ac
2 44 ac 28.21 ac
63 26 ac 44.59%

9.
Drainage Map

to be reduced using step 2 to adjust the flow rate for the basin's volume. (It needs a 3.2"
diameter orifice.)
11/2" skimmer:
1,728 cubic feet in 24 hours
6,912 cubic feet in 4 days
with a 1'/" head
3,456 cubic feet in 2 days
12,096 cubic feet in 7 days
5,184 cubic feet in 3 days
2" skimmer:
3,283 cubic feet in 24 hours
13,132 cubic feet in 4 days
with a 2" head
6,566 cubic feet in 2 days
22,982 cubic feet in 7 days
9,849 cubic feet in 3 days
2%" skimmer:
6,234 cubic feet in 24 hours
24,936 cubic feet in 4 days
with a 2.5" head
12,468 cubic feet in 2 days
43,638 cubic feet in 7 days
Revised 11-6-07
18,702 cubic feet in 3 days
3" skimmer:
9,774 cubic feet in 24 hours
39,096 cubic feet in 4 days
with a 3" head
19,547 cubic feet in 2 days
68,415 cubic feet in 7 days
29,322 cubic feet in 3 days
4" skimmer:
20,109 cubic feet in 24 hours
80,436 cubic feet in 4 days
with a 4" head
40,218 cubic feet in 2 days
140,763 cubic feet in 7 days
Revised 11-6-07
60,327 cubic feet in 3 days
5" skimmer:
32,832 cubic feet in 24 hours
131,328 cubic feet in 4 days
with a 4" head
65,664 cubic feet in 2 days
229,824 cubic feet in 7 days
98,496 cubic feet in 3 days
6" skimmer:
51,840 cubic feet in 24 hours
207,360 cubic feet in 4 days
with a 5" head
103,680 cubic feet in 2 days
362,880 cubic feet in 7 days
155,520 cubic feet in 3 days
8" skimmer:
97,978 cubic feet in 24 hours
391,912 cubic feet in 4 days
with a 6" head
195,956 cubic feet in 2 days
685,846 cubic feet in 7 days
CUSTOM
293,934 cubic feet in 3 days
MADE BY ORDER
CALL!
Determining the Orifice
Step 2. To determine the orifice required to reduce the flow rate for the basin's volume and the
number of days to drain the basin, simply use the formula volume = factor (from the chart
below) for the same size skimmer chosen in the first step and the same number of days. This
calculation will give the area of the required orifice. Then calculate the orifice radius using Area
= Tr r2 and solving for r, r = (Area 13.14) .The supplied cutter can be adjusted to this radius to
cut the orifice in the plug. The instructions with the plug and cutter has a ruler divided into tenths
of inches. Again, this step is not always necessary as explained above.
An alternative method is to use the orifice equation with the head for a particular skimmer
shown on the previous page and determine the orifice needed to give the required flow for the
volume and draw down time. C = 0.59 is used in this chart.
Example: A 4" skimmer is the smallest skimmer that will drain 39,000 cubic feet in 3 days but a
4" inlet will drain the basin too fast (in 1.9 days) To determine the orifice required use the factor
of 4,803 from the chart below for a 4" skimmer and a drawdown time of 3 days. 39,000 cubic
November 6, 2007 2

feet _ 4,803 = 8.12 square inches of orifice required. Calculate the orifice radius using Area = Z
r2 and solving for r, r = (8.12/3.14) and r = 1.61". As a practical matter 1.6" is about as close
as the cutter can be adjusted and the orifice cut..
Factors (in cubic feet of flow per square inch of opening through a round orifice with the head
for that skimmer and for,the drawdown times shown) for determining the orifice radius for a
basin's volume to be drained. This quick method works because the orifice is centered and has
a constant head (given above in Step 1).
1%" skimmer:
960 to drain in 24 hours
3,840 to drain in 4 days
9,677 to drain in 7 days
1,920 to drain in 2 days
6,720 to drain in 7 days
4" skimmer: 1,601 to drain in 24 hours
2,880 to drain in 3 days
Revised 11-6-07 3,202 to drain in 2 days
2" skimmer:
1,123 to drain in 24 hours
4,492 to drain in 4 days
2,246 to drain in 2 days
7,861 to drain in 7 days
3,369 to drain in 3 days
2'/2" skimmer
1,270 to drain in 24 hours
5,080 to drain in 4 days
Revised 11-6-07
2,540 to drain in 2 days
8,890 to drain in 7 days
3,810 to drain in 3 days
3" skimmer: 1,382 to drain in 24 hours
5,528 to drain in 4 days
2,765 to drain in 2 days
9,677 to drain in 7 days
4,146 to drain in 3 days
4" skimmer: 1,601 to drain in 24 hours
6,404 to drain in 4 days
Revised 11-6-07 3,202 to drain in 2 days
11,207 to drain in 7 days
4,803 to drain in 3 days
5" skimmer 1,642 to drain in 24 hours
6,568 to drain in 4 days
3,283 to drain in 2 days
11,491 to drain in 7 days
4,926 to drain in"3 days
6" skimmer: 1,814 to drain in 24 hours
7,256 to drain in 4 days
3,628 to drain in 2 days
12,701 to drain in 7 days
5,442 to drain in 3 days
8" skimmer: 1,987 to drain in 24 hours 7,948 to drain in 4 days
3,974 to drain in 2 days 13,909 to drain in 7 days
5,961 to drain in 3 days
J. W. Faircloth & Son, Inc.
Post Office Box 757
412-A Buttonwood Drive
Hillsborough, North Carolina 27278
Telephone [phone] FAX [phone]
FairclothSkimmer.com [e-mail]
Orifice sizing Revised 2-2-01, 3-3-05, 2-1-07, 11-6-07
November 6, 2007 3