20072022 Ver 4_2015-06-02 SIA_20150604

STORMWATER CALCULATIONS
for
Laurel Grove
5713 Leesville Road
Durham, North Carolina
ELC #1109 -001
October 24, 2014
Revised: June 2, 2015
Prepared for;
RREF II -FH Sierra LLC
2840 Plaza Place — Suite 360
Raleigh, North Carolina 27612
Prepared by:
HPOEDENS
LAND CORD
ENGINEERING - DEVELOPMENT
2314 South Miami Blvd
Suite 151
Durham, NC 27703
Tel. [phone]
www.edensland.com

TABLE OF CONTENTS
1.0 INTRODUCTION
1.1 Project Overview
1.2 Stormwater Design Requirements
2.0 HYDROLOGIC MODEL
2.1 Existing Conditions
2.2 Proposed Development
2.3 Basis for Design
2.4 Hydrologic Model Results and Conclusions
3.0 WATER QUALITY
3.1 Nutrient Load Overview
APPENDICES
APPENDIX I Hydrologic Analysis
APPENDIX II Water Quality Calculations
APPENDIX III Rip Rap & Plunge Pool Calculations
APPENDIX IV Storm System Analysis

1.0 INTRODUCTION
1.1 Project Overview
EDENS LAND CORP has been retained to evaluate existing and proposed storm water drainage
for Laurel Grove, a proposed residential project consisting of 493 units (mixture of single - family
and townhomes) in Durham, NC.
The project site is located on north side of Leesville Road, just west of Doc Nichols Road. The
parcel is currently within Durham city limits. The site lies in the Upper Falls basin but is not
subject to current stormwater regulations due to the original Site Plan (from 2006) still being
valid. The site is located in a water supply watershed (F /J -B).
Source: Durham GIS
Access to the development will be from both Doc Nichols Road and Leesville Road. The
development will consist of internal roadways with storm sewers and appurtenances, dry
detention basins, sanitary and water main service extensions, landscape improvements, and
earth moving activities.
1.2 Stormwater Design Requirements
This project is subject to the City of Durham stormwater requirements, in conjunction with the
State of North Carolina and applicable federal laws. This development is unique in that only
certain requirements pertain to the site due to the existing Site Plan approval on file:
• Detain runoff volume increase in the post development from the one -year, two year,
and ten year, 24 -hour storm event. Per the previously approved Site Plan, there only 3
analysis points.

• Limit Nitrogen export to 3.60 lb/acre/year
• The project is not subject to 85% TSS treatment of impervious surfaces
• General engineering design criteria for all projects shall be in accordance with 15A NCAC
2H .1008(c), as explained in the Stormwater BMP Design Manual.
• All other storm drainage design shall be in accordance with the City's stormwater design
requirements
2.0 HYDROLOGIC MODEL
2.1 Existing Conditions
The ±183.79 Acre site consists of mostly wooded areas, with minor improvements (shed, etc)
scattered throughout. It is estimated that the existing structures are in excess of 20 years old,
and therefore were in existence prior to the effective dates listed in the stormwater ordinance.
The surrounding land -uses are primarily single - family residences zoned RR.
7 r
~` £kiehar.i F -B
.r.
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2.2 Proposed Conditions
The development will yield 493 residential units with an average site area of approximately
8,000 square -feet (SF) each. Construction of the facility will disturb approximately 150.60
acres, with the balance of the site remaining forestland and /or un- maintained meadow.
2.3 Basis for Design
A hydrologic analysis of contributing watersheds was conducted to determine the peak runoff
rates for the 1 -year, 2 -year, and 10 -year storm events. The model was based on the City of
Durham Public Works 'Reference Guide for Development ", North Carolina Division of Water

Quality Stormwater Best Management Practices (BMPs) Manual, and standard engineering
practices. The hydrologic study was performed using the NRCS TR -55 Curve Number Method.
The computer modeling program Hydraf /ow Hydragraphs by Inte/iso/ve was used to calculate
the peak flow rates and model the bioretention for the desired storm events.
2.4 Hydrologic Model Results and Conclusions
The tract was analyzed and divided into watersheds based on the flow exiting the site and the
previously approved Site Plan. Four (4) specific analysis points were studied (see Drainage
Area Maps). The post development flow for 1 -year, 2 -year and 10 -year 24 hour storm for all
four analysis points is being reduced in comparison to the pre development flow.
Design Storm
ID
Land Use Condition
1 -year
2 -year
10 -year
CFS
CFS
CFS
Pre - development
82.58
135.51
346.13
Post Development
17.71
23.50
89.37
(with detention)
°
a
Post Development
63.91
100.08
236.85
(bypass)
a
Post Development
81.62
123.58
326.23
(total)
Increase( +) /decrease( -)
- 1.16%
-8.80%
-5.75%
ID
Land Use Condition
1 -year
2 -year
10 -year
CFS
CFS
CFS
Pre - development
13.34
17.90
33.88
LA rN Ln
Post Development
3.15
4.03
6.97
fa
Q a
Increase( +) /decrease( -)
- 76.39%
- 77.49%
- 79.43%
ID
Land Use Condition
1 -year
2 -year
10 -year
CFS
CFS
CFS
Pre - development
13.83
18.93
36.90
MA
Ln
f
Post Development
13.49
17.16
29.24
.
c OL
Q
Increase( +) /decrease( -)
-2.46%
-9.35%
-20.76%
ID
Land Use Condition
1 -year
2 -year
10 -year
CFS
CFS
CFS
Pre - development
2.56
3.48
6.70
c
a
Post Development
2.40
3.06
5.21
M
U)
2-
Increase( +) /decrease( -)
-6.25%
- 12.07%
-22.24%

3.0 WATER QUALITY
3.1 Nutrient Load Overview
This project lies within the Upper Neuse (Falls) Basin. New development in this basin is subject
to both nitrogen and phosphorous treatment. However, this project is subject only to the 3.60
Ib /ac /yr nitrogen requirement that was in effect at the time of original site plan approval.
Some areas of the site are being routed through level spreaders and engineered filter strips to
achieve nutrient load reduction. Cumulative areas for all LS & VFS are entered into the Jordan -
Falls Accounting Tool as 1 BMP to simplify calculations. Individual quantities for each LS & VFS
are included in its receptive design summary.
The chart below summarizes the nitrogen loading from the Jordan -Falls Accounting Tool. See
the attached spreadsheet in Appendix III for details.
Condition
Nitrogen
Nitrogen
(lb/ac/ r
(lb/ r)
Pre-Development
0.77
141.52
Post- Development
4.15
762.74
Post - Development
3.70
680.02
w/ BMP
The post development nitrogen export is 3.70 Ib /ac /yr, slightly above the allowed 3.60 Ib /ac /yr
threshold. A buy down from NCEEP will be required.

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5713 LEESVILLE ROAD
DURHAM, NORTH CAROLINA
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APPENDIX I
HYDROLOGIC ANALYSIS

Table 2 -4 Runoff Curve Numbersi
Cover Description
Curve Numbers for Hydrologic
Soil Groups
Cover type and hydrologic condition
A B
C
D
Cultivated land:
without conservation treatment
72
81
88
91
with conservation treatment
62
71
78
81
Pasture or range land
poor condition
68
79
86
89
good condition
39
61
74
80
Meadow:
good condition
30
58
71
78
Wood or forest land:
thin stand, poor cover
45
66
77
83
good cover
25
55
70
77
Open Space (lawns, parks, golf courses,
cemeteries, etc.) 2
Poor condition (grass cover <50 %)
68
79
86
89
Fair condition (grass cover 50% - 75 %)
49
69
79
84
Good condition (grass cover >75 %)
39
61
74
80
Impervious areas:
Paved parking lots, roofs, driveways, etc. (excluding
98
98
98
98
right -of -way)
Streets and Roads:
Paved; curbs and storm drains (excluding right -of-
98
98
98
98
way)
Paved; open ditches (including right -of -way)
83
89
92
93
Gravel (including right -of -way)
76
85
89
91
Dirt (including right -of -way)
72
82
87
89
Developing urban areas and newly graded areas
77
86
91
94
(pervious area only, no vegetation)
Raleigh Specific
Urban districts by zoning:
0&1 (III)
96
97
98
98
0&1 (1 & 11)
98
98
98
98
Buffer Community, Shopping Center, Neighborhood
Business, Industrial I & II
Residential districts by zoning:
R -4
61
75
83
87
R -6
71
80
87
92
R -10
80
85
90
95
R -20
86
90
93
96
R -30
92
94
96
97
1 Average runoff condition, and la = 0.2S
2 CNs shown are equivalent to those of pasture. Composite CNs may be computed for
other combinations of open space cover type.
Assumptions are as follows: impervious areas are directly connected to the drainage system,
impervious areas have a CN of 98, and
pervious areas are considered equivalent to open space in good
hydrologic condition.
If the impervious area is not connected, the
NRCS method has an adjustment to reduce the effect.
City of Raleigh January 2002
Stormwater Design Manual Page 52

216!13 Manning's Roughness Coefficient
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Clay the
0 -014
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0 -011
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Floodplains - heavy brush
Flood pl ain s - trees
Galvanized iron
Glass _
Gravel
Lead
Masonry
Metal - corrugated
Natural streams- clean and
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Natural streams - sluggish with
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Plastic
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Polyethylene PE - Corrugated
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0 -012
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0 -012
Wood - unplaned
0 -013
Wood stave
0.012
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OVERALL PRE

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 1
Pre AP #1
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 222.760 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4 6
Hyd No. 1
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #1
Hyd. No. 1 -- 1 Year
Tuesday, 10 / 21 / 2014
82.58 cfs
12.23 hrs
440,463 cuft
66
Oft
28.50 min
Type II
484
Q (cfs)
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
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. No. 1
Pre AP #1
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 222.760 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
140.00
120.00
100.00
:� 11
•1 11
40.00
20.00
0.00 ' '
0 2 4
Hyd No. 1
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #1
Hyd. No. 1 -- 2 Year
Tuesday, 10 / 21 / 2014
135.51 cfs
12.20 hrs
647,147 cuft
66
Oft
28.50 min
Type II
484
Q (cfs)
140.00
120.00
100.00
:1 11
•1 11
40.00
20.00
i i i i I I I I I I I1% ' 0.00
6 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
Pre AP #1
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 222.760 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
350.00
250.00
a111 1111M
150.00
100.00
50.00
0.00 ' '
0 2 4
Hyd No. 1
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #1
Hyd. No. 1 -- 10 Year
Tuesday, 10 / 21 / 2014
346.13 cfs
12.20 hrs
1,452,378 cuft
66
Oft
28.50 min
Type II
484
Q (cfs)
350.00
300.00
250.00
200.00
150.00
100.00
50.00
i i I I I I I I I� 1 0.00
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
Pre AP #1
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 222.760 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
707.00
505.00
404.00
303.00
202.00
101.00
0.00 ' '
0 2 4
Hyd No. 1
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #1
Hyd. No. 1 -- 100 Year
Tuesday, 10 / 21 / 2014
704.80 cfs
12.20 hrs
2,847,628 cuft
66
Oft
28.50 min
Type II
484
Q (cfs)
707.00
505.00
404.00
303.00
202.00
101.00
.- 1 1 1 1 1 1 11 1 0.00
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. 3
Pre AP #2
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 7.890 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Pre AP #2
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Tuesday, 10 / 21 / 2014
13.34 cfs
12.00 hrs
30,675 cuft
77
Oft
9.80 min
Type II
484
Q (cfs) Hyd. No. 3 -- 1 Year Q (cfs)
14.00 14.00
12.00 12.00
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 3 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 3
Pre AP #2
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 7.890 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
18.00
15.00
12.00
3.00
0.00 '
0 2 4
Hyd No. 3
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #2
Hyd. No. 3 -- 2 Year
Tuesday, 10 / 21 / 2014
17.90 cfs
12.00 hrs
40,970 cuft
77
Oft
9.80 min
Type II
484
Q (cfs)
18.00
15.00
12.00
11111M
3.00
1 - ' ' ' ' 0.00
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. 3
Pre AP #2
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 7.890 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00 ' '
0 2 4
Hyd No. 3
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #2
Hyd. No. 3 -- 10 Year
Tuesday, 10 / 21 / 2014
33.88 cfs
11.97 hrs
77,527 cuft
77
Oft
9.80 min
Type II
484
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
' ' ' 0.00
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. 3
Pre AP #2
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 7.890 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 3
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #2
Hyd. No. 3 -- 100 Year
Tuesday, 10 / 21 / 2014
58.46 cfs
11.97 hrs
135,384 cuft
77
Oft
9.80 min
Type II
484
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
"r ' ' ' ' 0.00
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. 5
Pre AP #3
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 9.190 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
14.00
12.00
10.00
. M
4.00
2.00
0.00 '
0 2 4
Hyd No. 5
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #3
Hyd. No. 5 -- 1 Year
Tuesday, 10 / 21 / 2014
13.83 cfs
12.00 hrs
32,051 cuft
75
Oft
9.80 min
Type II
484
Q (cfs)
14.00
12.00
10.00
11111M
4.00
f►a[iIi�
' ' ' ' 0.00
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. 5
Pre AP #3
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 9.190 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
21.00
18.00
15.00
12.00
• m
MM
3.00
0.00 '
0 2 4
Hyd No. 5
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #3
Hyd. No. 5 -- 2 Year
Tuesday, 10 / 21 / 2014
18.93 cfs
12.00 hrs
43,428 cuft
75
Oft
9.80 min
Type II
484
Q (cfs)
21.00
18.00
15.00
12.00
• 11
91-UM
3.00
�� ' ' ' I I I M 1 0.00
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. 5
Pre AP #3
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 9.190 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= TR55
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
40.00
30.00
20.00
10.00
0.00 ' '
0 2 4
Hyd No. 5
Pre AP #3
Hyd. No. 5 -- 10 Year
6 8 10 12 14 16
Tuesday, 10 / 21 / 2014
= 36.90 cfs
= 11.97 hrs
= 84,421 cuft
= 75
= Oft
= 9.80 min
= Type II
= 484
Q (cfs)
40.00
30.00
20.00
10.00
- ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 5
Pre AP #3
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 9.190 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
70.00
50.00
FA�
30.00
20.00
10.00
0.00 ' 1 '
0 2 4
Hyd No. 5
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #3
Hyd. No. 5 -- 100 Year
Tuesday, 10 / 21 / 2014
65.20 cfs
11.97 hrs
150,244 cuft
75
Oft
9.80 min
Type II
484
Q (cfs)
70.00
50.00
40.00
30.00
20.00
10.00
'r— ' ' ' 0.00
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. 7
Pre AP #4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 1.570 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.00 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
3.00
2.00
1.00
0.00 ' '
0 2 4
Hyd No. 7
Pre AP #4
Hyd. No. 7 -- 1 Year
6 8 10 12 14 16
Tuesday, 10 / 21 / 2014
= 2.560 cfs
= 11.97 hrs
= 5,133 cuft
= 75
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
3.00
2.00
1.00
0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 7
Pre AP #4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 1.570 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.50 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
4.00
3.00
2.00
1.00
0.00 ' '
0 2 4
Hyd No. 7
Pre AP #4
Hyd. No. 7 -- 2 Year
6 8 10 12 14 16
Tuesday, 10 / 21 / 2014
= 3.478 cfs
= 11.97 hrs
= 6,955 cuft
= 75
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
4.00
3.00
2.00
1.00
0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 7
Pre AP #4
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 1.570 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
7.00
. M
5.00
4.00
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 7
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Pre AP #4
Hyd. No. 7 -- 10 Year
Tuesday, 10 / 21 / 2014
6.695 cfs
11.93 hrs
13,521 cuft
75
Oft
5.00 min
Type II
484
Q (cfs)
7.00
11111M
5.00
4.00
3.00
2.00
1.00
'`o� ' ' ' ' 0.00
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. 7
Pre AP #4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 100 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 1.570 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 7.40 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
12.00
10.00
4.00
2.00
0.00 ' '
0.0 2.0 4.0
Hyd No. 7
6.0 8.0
Pre AP #4
Hyd. No. 7 -- 100 Year
Tuesday, 10 / 21 / 2014
= 11.77 cfs
= 11.93 hrs
= 24,063 cuft
= 75
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
12.00
10.00
4.00
2.00
T ' ' 0.00
10.0 12.0 14.0 16.0 18.0 20.0 22.0
Time (hrs)

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Watershed Model Schematic Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
ost Area to Pond 1
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Post Area to Pond 4
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Post Area to Pond 5
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ost Area to Ponds 6
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�Post Area to Pond 7
5 -P
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Post Area to Pond 8
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32 - Route
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Area to Pond 9
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3-9�,Post Area to Pond 10
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4 onds 7 - 10
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Project: 2015 -02 -18 Post Analysis.gpw I Wednesday, 02 / 18 / 2015

1
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Monday, 05 / 4 / 2015
Hyd. No. 49
Post AP #1
Hydrograph type
= Combine Peak discharge
= 81.62 cfs
Storm frequency
= 1 yrs Time to peak
= 12.20 hrs
Time interval
= 2 min Hyd. volume
= 860,365 cuft
Inflow hyds.
= 43, 45, 47 Contrib. drain. area
= 128.870 ac
Post AP #1
Q (cfs) Hyd. No. 49 -- 1 Year Q (cfs)
90.00 90.00
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 T 10.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36 40
Time (hrs)
Hyd No. 49 Hyd No. 43 Hyd No. 45 Hyd No. 47

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Monday, 05 / 4 / 2015
Hyd. No. 49
Post AP #1
Hydrograph type
= Combine Peak discharge
= 123.58 cfs
Storm frequency
= 2 yrs Time to peak
= 12.20 hrs
Time interval
= 2 min Hyd. volume
= 1,145,873 cuft
Inflow hyds.
= 43, 45, 47 Contrib. drain. area
= 128.870 ac
Post AP #1
Q (cfs) Hyd. No. 49 -- 2 Year Q (cfs)
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36 40
Time (hrs)
Hyd No. 49 Hyd No. 43 Hyd No. 45 Hyd No. 47

I
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Monday, 05 / 4 / 2015
Hyd. No. 49
Post AP #1
Hydrograph type
= Combine Peak discharge
= 326.23 cfs
Storm frequency
= 10 yrs Time to peak
= 12.17 hrs
Time interval
= 2 min Hyd. volume
= 2,169,495 cuft
Inflow hyds.
= 43, 45, 47 Contrib. drain. area
= 128.870 ac
Post AP #1
Q (cfs) Hyd. No. 49 -- 10 Year Q (cfs)
350.00 350.00
300.00 300.00
250.00 250.00
200.00 200.00
150.00 150.00
100.00 100.00
50.00 50.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36
Time (hrs)
Hyd No. 49 Hyd No. 43 Hyd No. 45 Hyd No. 47

4
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Monday, 05 / 4 / 2015
Hyd. No. 49
Post AP #1
Hydrograph type
= Combine Peak discharge
= 870.14 cfs
Storm frequency
= 100 yrs Time to peak
= 12.17 hrs
Time interval
= 2 min Hyd. volume
= 3,811,203 cuft
Inflow hyds.
= 43, 45, 47 Contrib. drain. area
= 128.870 ac
Post AP #1
Q (cfs) Hyd. No. 49 -- 100 Year Q (cfs)
875.00 875.00
750.00 750.00
625.00 625.00
500.00 500.00
375.00 375.00
250.00 250.00
125.00 125.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 49 Hyd No. 43 Hyd No. 45 Hyd No. 47

1
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 45
Ponds 1 - 6
Hydrograph type = Combine Peak discharge = 18.03 cfs
Storm frequency = 1 yrs Time to peak = 12.57 hrs
Time interval = 2 min Hyd. volume = 426,861 cuft
Inflow hyds. = 5, 9, 13, 17, 21, 25 Contrib. drain. area = 0.000 ac
Q (cfs)
21.00
18.00
15.00
12.00
am
. 11
3.00
0.00
0 4 8
Hyd No. 45
Ponds 1 - 6
Hyd. No. 45 -- 1 Year
12 16
Hyd No. 5
Hyd No. 17
20 24 28
Hyd No. 9
Hyd No. 21
Q (cfs)
21.00
18.00
15.00
12.00
• 11
11111M
3.00
- 0.00
32 36 40 44
Hyd No. 13 Time (hrs)
Hyd No. 25

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 45
Ponds 1 - 6
Hydrograph type = Combine Peak discharge = 25.39 cfs
Storm frequency = 2 yrs Time to peak = 12.60 hrs
Time interval = 2 min Hyd. volume = 542,542 cuft
Inflow hyds. = 5, 9, 13, 17, 21, 25 Contrib. drain. area = 0.000 ac
Q (cfs)
28.00
24.00
20.00
16.00
12.00
F-WIT111
4.00
.rm
Ponds 1 - 6
Hyd. No. 45 -- 2 Year
— _ -
0 4 8 12 16 20 24 28 32
Hyd No. 45 Hyd No. 5 Hyd No. 9
Hyd No. 17 Hyd No. 21
36 40 44
Hyd No. 13
Hyd No. 25
Q (cfs)
28.00
24.00
20.00
16.00
12.00
OR
4.00
48
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Hyd. No. 45
Ponds 1 - 6
Hydrograph type
= Combine
Storm frequency
= 10 yrs
Time interval
= 2 min
Inflow hyds.
= 5, 9, 13, 17, 21, 25
Q (cfs)
70.00
50.00
FA�
30.00
20.00
10.00
.rm
Ponds 1 - 6
I
Monday, 05 / 4 / 2015
Peak discharge = 65.54 cfs
Time to peak = 12.23 hrs
Hyd. volume = 933,227 cuft
Contrib. drain. area = 0.000 ac
Hyd. No. 45 -- 10 Year Q (cfs)
70.00
60.00
50.00
40.00
30.00
20.00
10.00
- 0 00
0 4 8 12 16 20 24 28 32
Hyd No. 45 Hyd No. 5 Hyd No. 9
Hyd No. 17 Hyd No. 21
36 40 44
Hyd No. 13
Hyd No. 25
48
Time (hrs)

4
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 45
Ponds 1 - 6
Hydrograph type = Combine Peak discharge = 285.38 cfs
Storm frequency = 100 yrs Time to peak = 12.20 hrs
Time interval = 2 min Hyd. volume = 1,522,437 cuft
Inflow hyds. = 5, 9, 13, 17, 21, 25 Contrib. drain. area = 0.000 ac
Ponds 1 - 6
Q (cfs) Hyd. No. 45 -- 100 Year Q (cfs)
320.00 320.00
280.00 280.00
240.00 240.00
200.00 200.00
160.00 160.00
120.00 120.00
80.00 80.00
40.00 40.00
0.00 0.00
0 4 8 12 16 20 24 28 32
Hyd No. 45 Hyd No. 5 Hyd No. 9 Hyd No. 13 Time (hrs)
Hyd No. 17 Hyd No. 21 Hyd No. 25

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Hyd. No. 47
Ponds 7 - 10
Hydrograph type
= Combine Peak discharge
Storm frequency
= 1 yrs Time to peak
Time interval
= 2 min Hyd. volume
Inflow hyds.
= 29, 33, 37, 41 Contrib. drain. area
Q (cfs)
8.00
. id
i KO
2.00
0.00
0 4
Hyd No. 47
Ponds 7 - 10
Hyd. No. 47 -- 1 Year
8 12
Hyd No. 29
Hyd No. 41
16 20 24
Hyd No. 33
1
Monday, 05 / 4 / 2015
= 7.544 cfs
= 12.50 hrs
= 144,997 cuft
= 0.000 ac
28 32
Hyd No. 37
Q (cfs)
8.00
. KQ
4.00
2.00
—l'- 0.00
36
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 47
Ponds 7 - 10
Hydrograph type = Combine Peak discharge = 9.371 cfs
Storm frequency = 2 yrs Time to peak = 12.47 hrs
Time interval = 2 min Hyd. volume = 188,301 cuft
Inflow hyds. = 29, 33, 37, 41 Contrib. drain. area = 0.000 ac
Q (cfs)
10.00
: IM
4.00
2.00
0.00
0 4
Hyd No. 47
Ponds 7 - 10
Hyd. No. 47 -- 2 Year
8 12 16
Hyd No. 29
Hyd No. 41
20 24
Hyd No. 33
28 32 36
Hyd No. 37
Q (cfs)
10.00
11111M
4.00
2.00
—l'- 0.00
40
Time (hrs)

I
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 47
Ponds 7 - 10
Hydrograph type = Combine Peak discharge = 31.84 cfs
Storm frequency = 10 yrs Time to peak = 12.20 hrs
Time interval = 2 min Hyd. volume = 337,813 cuft
Inflow hyds. = 29, 33, 37, 41 Contrib. drain. area = 0.000 ac
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00 ' 1 1
0 4 8
Hyd No. 47
Ponds 7 - 10
Hyd. No. 47 -- 10 Year
12 16
Hyd No. 29
Hyd No. 41
20 24 28
Hyd No. 33
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
32 36 40 44
Time (hrs)
Hyd No. 37

4
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Monday, 05 / 4 / 2015
Hyd. No. 47
Ponds 7 - 10
Hydrograph type
= Combine Peak discharge
= 141.67 cfs
Storm frequency
= 100 yrs Time to peak
= 12.10 hrs
Time interval
= 2 min Hyd. volume
= 568,170 cuft
Inflow hyds.
= 29, 33, 37, 41 Contrib. drain. area
= 0.000 ac
Ponds 7 - 10
Q (cfs) Hyd. No. 47 -- 100 Year Q (cfs)
160.00 160.00
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Hyd No. 47 Hyd No. 29 Hyd No. 33 Hyd No. 37 Time (hrs)
Hyd No. 41

A)
Worksheet 2: Runoff curve number and runoff
Project:
Laurel Grove
By:
AFL
Date:
10/20/14
Location:
Impervious -Roof
Checked:
Date:
0.26
Circle one:
Present Developed Watershed:
Post AP #2
98
1.) Runoff curve number (CN)
0.02
1.96
--
Impervious - Sidewalk
98
Soil Name
Cover Description
0.05
CN Value'
D
Area
Product
0.64
51.20
B
and
55
of
0.06
3.30
Hydrologic
(cover type, treatment, and
77
0.26
20.02
CN x Area
Group
hydrologic condition;
N
N
N
Acres
percent impervious;
Sq. Ft.
unconnected /connected impervious
�
LM
Use only one CN value source per line. Totals =
M
106.86
(
0.00202
sq mi)
total product
106.86
CN (weighted) = _
Use CN =
83
total area
1.29
A)
area ratio)
�
--
Impervious -Roof
98
0.26
25.48
--
Impervious -Road
98
0.02
1.96
--
Impervious - Sidewalk
98
0.05
4.90
D
Open Space -Lawn -Good Condition
80
0.64
51.20
B
Wood -Good Cover
55
0.06
3.30
D
Wood -Good Cover
77
0.26
20.02
Use only one CN value source per line. Totals =
1.29
106.86

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 51
Post AP #2
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 1.290 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.00 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
4.00
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 51
Post AP #2
Hyd. No. 51 -- 1 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 3.145 cfs
= 11.93 hrs
= 6,350 cuft
= 83
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
4.00
3.00
2.00
1.00
0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 51
Post AP #2
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 1.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
5.00
4.00
3.00
2.00
1.00
0.00 ' '
0 2 4
Hyd No. 51
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #2
Hyd. No. 51 -- 2 Year
6 8 10 12 14
Wednesday, 01 / 7 / 2015
4.032 cfs
11.93 hrs
8,159 cuft
83
Oft
5.00 min
Type II
484
Q (cfs)
5.00
4.00
3.00
2.00
1.00
0.00
16 18 20 22 24
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 51
Post AP #2
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 1.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0 00
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #2
Hyd. No. 51 -- 10 Year
Wednesday, 01 / 7 / 2015
6.968 cfs
11.93 hrs
14,332 cuft
83
Oft
5.00 min
Type II
484
Q (cfs)
7.00
11111M
5.00
4.00
3.00
2.00
1.00
Nil Mes
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Hyd No. 51 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 51
Post AP #2
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 1.290 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Post AP #2
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Wednesday, 01 / 7 / 2015
11.25 cfs
11.93 hrs
23,734 cuft
83
Oft
5.00 min
Type II
484
Q (cfs) Hyd. No. 51 -- 100 Year Q (cfs)
12.00 12.00
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Hyd No. 51 Time (hrs)

A)
Worksheet 2: Runoff curve number and runoff
Project:
Laurel Grove
By:
AFL
Date:
12/17/14
Location:
Impervious -Roof
Checked:
Date:
0.57
Circle one:
Present Developed Watershed:
Post AP #3
98
1.) Runoff curve number (CN)
0.73
71.54
--
Impervious - Sidewalk
98
Soil Name
Cover Description
0.16
CN Value'
--
Area
Product
0.04
3.92
C
and
74
of
0.57
42.18
Hydrologic
(cover type, treatment, and
80
3.15
252.00
CN x Area
Group
hydrologic condition;
N
N
N
Acres
percent impervious;
Sq. Ft.
unconnected /connected impervious
�
LM
Use only one CN value source per line. Totals =
M
441.18
(
0.00816
sq mi)
total product
441.18
CN (weighted) = _
Use CN =
85
total area
5.22
A)
area ratio)
�
--
Impervious -Roof
98
0.57
55.86
--
Impervious -Road
98
0.73
71.54
--
Impervious - Sidewalk
98
0.16
15.68
--
Impervious - Driveway
98
0.04
3.92
C
Open Space -Lawn -Good Condition
74
0.57
42.18
D
Open Space -Lawn -Good Condition
80
3.15
252.00
Use only one CN value source per line. Totals =
5.22
441.18

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 53
Post AP #3
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 5.280 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
14.00
12.00
10.00
. M
4.00
2.00
0.00 '
0 2 4
Hyd No. 53
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #3
Hyd. No. 53 -- 1 Year
Wednesday, 01 / 7 / 2015
13.49 cfs
11.93 hrs
27,245 cuft
84
Oft
5.00 min
Type II
484
Q (cfs)
14.00
12.00
10.00
11111M
4.00
f►a[iIi�
-0-- ' ' 0.00
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. 53
Post AP #3
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 5.280 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Post AP #3
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Wednesday, 01 / 7 / 2015
17.16 cfs
11.93 hrs
34,795 cuft
84
Oft
5.00 min
Type II
484
Q (cfs) Hyd. No. 53 -- 2 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24
Hyd No. 53 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 53
Post AP #3
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 5.280 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
0.00 ' '
0.0 2.0 4.0
Hyd No. 53
6.0 8.0
Post AP #3
Hyd. No. 53 -- 10 Year
Wednesday, 01 / 7 / 2015
= 29.24 cfs
= 11.93 hrs
= 60,411 cuft
= 84
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
T ' ' ' 0.00
10.0 12.0 14.0 16.0 18.0 20.0 22.0
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 53
Post AP #3
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 5.280 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00 ' '
0.0 2.0 4.0
Hyd No. 53
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #3
Hyd. No. 53 -- 100 Year
Wednesday, 01 / 7 / 2015
46.77 cfs
11.93 hrs
99,201 cuft
84
Oft
5.00 min
Type II
484
Q (cfs)
50.00
40.00
30.00
20.00
10.00
' ' 0.00
6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Time (hrs)

A)
Worksheet 2: Runoff curve number and runoff
Project:
Laurel Grove
By:
AFL
Date:
10/20/14
Location:
Impervious -Roof
Checked:
Date:
0.08
Circle one:
Present Developed Watershed:
Post AP #4
98
1.) Runoff curve number (CN)
0.10
9.80
--
Impervious - Sidewalk
98
Soil Name
Cover Description
0.04
CN Value'
D
Area
Product
0.72
57.60
and
of
Hydrologic
(cover type, treatment, and
CN x Area
Group
hydrologic condition;
N
N
N
Acres
percent impervious;
N
L
L
Sq. Ft.
Use only one CN value source per line. Totals =
0.94
79.16
unconnected /connected impervious
a,
LM
M
(
0.00147
sq mi)
total product
79.16
CN (weighted) = _
Use CN =
84
total area
0.94
A)
area ratio)
�
--
Impervious -Roof
98
0.08
7.84
--
Impervious -Road
98
0.10
9.80
--
Impervious - Sidewalk
98
0.04
3.92
D
Open Space -Lawn -Good Condition
80
0.72
57.60
Use only one CN value source per line. Totals =
0.94
79.16

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 55
Post AP #4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.940 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.00 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 55
Post AP #4
Hyd. No. 55 -- 1 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 2.401 cfs
= 11.93 hrs
= 4,851 cuft
= 84
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
3.00
2.00
1.00
0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 55
Post AP #4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.940 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.50 in
Distribution
Storm duration
= 24 hrs
Shape factor
Post AP #4
Wednesday, 01 / 7 / 2015
= 3.055 cfs
= 11.93 hrs
= 6,195 cuft
= 84
= Oft
= 5.00 min
= Type II
= 484
Q (cfs) Hyd. No. 55 -- 2 Year Q (cfs)
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24
Hyd No. 55 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 55
Post AP #4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.940 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
0.00 ' '
0.0 2.0 4.0
Hyd No. 55
6.0 8.0
Post AP #4
Hyd. No. 55 -- 10 Year
Wednesday, 01 / 7 / 2015
= 5.206 cfs
= 11.93 hrs
= 10,755 cuft
= 84
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
T ' 0.00
10.0 12.0 14.0 16.0 18.0 20.0 22.0
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 55
Post AP #4
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 0.940 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Post AP #4
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Wednesday, 01 / 7 / 2015
8.326 cfs
11.93 hrs
17,661 cuft
84
Oft
5.00 min
Type II
484
Q (cfs) Hyd. No. 55 -- 100 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Hyd No. 55 Time (hrs)

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL
Location: Checked:
Circle one: Present Developed Watershed: Post AP #1 Bypass
1.) Runoff curve number (CN)
Date: 12/17/14
Date:
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
%
Product
of
CN x Area
N
N
L
'a,
LL
N
L
LL
--
Impervious - Roof
98
5.91
579.18
--
Impervious - Road
98
2.39
234.22
--
Impervious - Sidewalk
98
0.30
29.40
--
Impervious - Driveway
98
0.82
80.36
B
Open Space - Lawn - Good Condition
61
22.10
1348.10
C
Open Space - Lawn - Good Condition
74
3.84
284.16
D
Open Space - Lawn - Good Condition
80
22.47
1797.60
B
Wood - Good Cover
55
48.67
2676.85
C
Wood - Good Cover
70
0.44
30.80
D
Wood - Good Cover
77
21.93
1688.61
Use only one CN value source per line. Totals =
128.87
8749.28
( 0.20136 sq mi)
CN (weighted) = total product = 8749.28 Use CN - 68
total area 128.87

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 43
Post AP #1 Bypass
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 128.870 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
70.00
50.00
FA�
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 43
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #1 Bypass
Hyd. No. 43 -- 1 Year
Wednesday, 01 / 7 / 2015
63.91 cfs
12.17 hrs
288,506 cuft
68
Oft
26.30 min
Type II
484
Q (cfs)
70.00
50.00
40.00
30.00
20.00
10.00
1 9 I 1 1 1 1 1 I N 1 0.00
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. 43
Post AP #1 Bypass
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 128.870 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
120.00
100.00
F�
20.00
0.00 ' '
0 2 4
Hyd No. 43
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #1 Bypass
Hyd. No. 43 -- 2 Year
Wednesday, 01 / 7 / 2015
100.08 cfs
12.17 hrs
415,031 cuft
68
Oft
26.30 min
Type II
484
Q (cfs)
120.00
100.00
80.00
60.00
40.00
20.00
0.00
6 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. 43
Post AP #1 Bypass
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 128.870 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
240.00
210.00
180.00
150.00
120.00
•1 11
•1 11
30.00
0.00
0 2 4
Hyd No. 43
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #1 Bypass
Hyd. No. 43 -- 10 Year
Wednesday, 01 / 7 / 2015
236.85 cfs
12.17 hrs
898,453 cuft
68
Oft
26.30 min
Type II
484
Q (cfs)
240.00
210.00
180.00
150.00
120.00
•1 11
•1 11
30.00
i i I I I I I I I I� 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. No. 43
Post AP #1 Bypass
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 128.870 ac
Basin Slope
= 0.0%
Tc method
= TR55
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
490.00
420.00
350.00
Q-111 1111M
210.00
140.00
70.00
0.00
0 2 4
Hyd No. 43
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post AP #1 Bypass
Hyd. No. 43 -- 100 Year
Wednesday, 01 / 7 / 2015
466.69 cfs
12.13 hrs
1,720,595 cuft
68
Oft
26.30 min
Type II
484
Q (cfs)
490.00
420.00
350.00
280.00
210.00
140.00
70.00
0.00
6 8 10 12 14 16 18 20 22 24 26
Time (hrs)

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Developed Watershed: AP -1 to Pond 1
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
Product
of
CN x Area
N
N
M
�
N
L
'a.,
�
N
L
2)
LL
2.95
289.10
--
Impervious -Road
98
1.42
139.16
--
Impervious - Sidewalk
98
0.23
22.54
--
Impervious - Driveway
98
0.55
53.90
B
Open Space -Lawn -Good Condition
61
0.29
17.69
C
Open Space -Lawn -Good Condition
74
1.77
130.98
D
Open Space -Lawn -Good Condition
80
2.74
219.20
Use only one CN value source per line. Totals =
9.95
872.57
( 0.01555 sq mi)
CN (weighted) = total product = 872.57 Use CN = 88
total area 9.95
--
Impervious -Roof
98
2.95
289.10
--
Impervious -Road
98
1.42
139.16
--
Impervious - Sidewalk
98
0.23
22.54
--
Impervious - Driveway
98
0.55
53.90
B
Open Space -Lawn -Good Condition
61
0.29
17.69
C
Open Space -Lawn -Good Condition
74
1.77
130.98
D
Open Space -Lawn -Good Condition
80
2.74
219.20
Use only one CN value source per line. Totals =
9.95
872.57

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 3
Post Area to Pond 1
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 9.950 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
28.00
24.00
20.00
16.00
12.00
1I
4.00
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 1
Hyd. No. 3 -- 1 Year
Wednesday, 01 / 7 / 2015
26.03 cfs
12.00 hrs
67,722 cuft
88
Oft
12.90 min
Type II
484
Q (cfs)
28.00
24.00
20.00
16.00
12.00
Ki 11
4.00
0.00 ' — - ' ' ' 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 3 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 3
Post Area to Pond 1
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 9.950 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00 ' '
0 2 4
Hyd No. 3
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 1
Hyd. No. 3 -- 2 Year
Wednesday, 01 / 7 / 2015
32.30 cfs
12.00 hrs
84,502 cuft
88
Oft
12.90 min
Type II
484
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
-r ' ' ' 0.00
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. 3
Post Area to Pond 1
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 9.950 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00 '
0 2 4
Hyd No. 3
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 1
Hyd. No. 3 -- 10 Year
Wednesday, 01 / 7 / 2015
52.52 cfs
12.00 hrs
140,198 cuft
88
Oft
12.90 min
Type II
484
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
-' ' ' 0.00
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. 3
Post Area to Pond 1
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 9.950 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4 6
Hyd No. 3
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 1
Hyd. No. 3 -- 100 Year
I WNW
Wednesday, 01 / 7 / 2015
81.43 cfs
12.00 hrs
222,837 cuft
88
Oft
12.90 min
Type II
484
Q (cfs)
90.00
80.00
70.00
60.00
50.00
40.00

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 4
Pond 1 Route
Hydrograph type
= Reservoir
Peak discharge
= 0.963 cfs
Storm frequency
= 1 yrs
Time to peak
= 14.27 hrs
Time interval
= 2 min
Hyd. volume
= 67,700 cuft
Inflow hyd. No.
= 3 - Post Area to Pond 1
Max. Elevation
= 387.68 ft
Reservoir name
= Pond 1
Max. Storage
= 40,666 cuft
Storage Indication method used.
Q (cfs)
28.00
24.00
20.00
16.00
12.00
1I
4.00
0.00
0 4 8
Hyd No. 4
Pond 1 Route
Hyd. No. 4 -- 1 Year
Q (cfs)
28.00
24.00
20.00
16.00
12.00
Ki 11
4.00
0.00
12 16 20 24 28 32 36 40 44 48
Time (hrs)
Hyd No. 3 1111111 Total storage used = 40,666 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 4
Pond 1 Route
Hydrograph type
= Reservoir
Peak discharge
= 1.057 cfs
Storm frequency
= 2 yrs
Time to peak
= 14.73 hrs
Time interval
= 2 min
Hyd. volume
= 84,480 cuft
Inflow hyd. No.
= 3 - Post Area to Pond 1
Max. Elevation
= 388.78 ft
Reservoir name
= Pond 1
Max. Storage
= 52,411 cuft
Storage Indication method used.
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00 '
0 4 8
Hyd No. 4
Pond 1 Route
Hyd. No. 4 -- 2 Year
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
12 16 20 24 28 32 36 40 44 48 52
Time (hrs)
Hyd No. 3 1111111 Total storage used = 52,411 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 4
Pond 1 Route
Hydrograph type
= Reservoir
Peak discharge
= 1.600 cfs
Storm frequency
= 10 yrs
Time to peak
= 14.80 hrs
Time interval
= 2 min
Hyd. volume
= 140,176 cuft
Inflow hyd. No.
= 3 - Post Area to Pond 1
Max. Elevation
= 391.77 ft
Reservoir name
= Pond 1
Max. Storage
= 90,697 cuft
Storage Indication method used
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00 '
0 6
Hyd No. 4
Pond 1 Route
Hyd. No. 4 -- 10 Year
12 18 24
Hyd No. 3
30 36 42 48 54
011111 Total storage used = 90,697 cuft
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
1 0.00
60
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 4
Pond 1 Route
Hydrograph type
= Reservoir
Peak discharge
= 28.04 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.20 hrs
Time interval
= 2 min
Hyd. volume
= 222,814 cuft
Inflow hyd. No.
= 3 - Post Area to Pond 1
Max. Elevation
= 393.06 ft
Reservoir name
= Pond 1
Max. Storage
= 110,273 cuft
Storage Indication method used.
Q (cfs
90.00
80.00
70.00
60.00
50.00
40.00
'• • 1 Route
• No. 4 100 Year
Q (cfs)
90.00
80.00
70.00
60.00
50.00
40.00
1 11 -- --- - - - - -- 1 11

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 5
Pond 1 to AP #1
Hydrograph type
= Reach
Peak discharge
= 0.962 cfs
Storm frequency
= 1 yrs
Time to peak
= 14.70 hrs
Time interval
= 2 min
Hyd. volume
= 67,501 cuft
Inflow hyd. No.
= 4 - Pond 1 Route
Section type
= Trapezoidal
Reach length
= 3973.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.13 ft /s
Routing coeff.
= 0.1098
Modified Att -Kin routing method used.
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0 4 8
Hyd No. 5
Pond 1 to AP #1
Hyd. No. 5 -- 1 Year
12 16 20
Hyd No. 4
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
24 28 32 36 40 44 48
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 5
Pond 1 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 4 - Pond 1 Route
Section type
Reach length
= 3973.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.18 ft /s
Routing coeff.
Modified Att -Kin routing method used.
Q (cfs)
2.00
1.00
0.00
0 4 8
Hyd No. 5
12 16 20
Hyd No. 4
Pond 1 to AP #1
Hyd. No. 5 -- 2 Year
Wednesday, 02 / 18 / 2015
= 1.057 cfs
= 15.07 hrs
= 84,280 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1116
24 28 32 36 40 44 48
Q (cfs)
2.00
1.00
—1-- 0.00
52
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 5
Pond 1 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 4 - Pond 1 Route
Section type
Reach length
= 3973.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.44 ft /s
Routing coeff.
Modified Att -Kin routing method used.
Q (cfs)
2.00
1.00
W 1 11 �
6 12
Hyd No. 5
Pond 1 to AP #1
Hyd. No. 5 -- 10 Year
18 24 30
Hyd No. 4
Wednesday, 02 / 18 / 2015
= 1.598 cfs
= 15.10 hrs
= 139,976 cuft
= Trapezoidal
1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1201
36 42 48 54
Q (cfs)
2.00
1.00
al_ 0.00
60
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 5
Pond 1 to AP #1
Hydrograph type
= Reach
Peak discharge
= 22.56 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.37 hrs
Time interval
= 2 min
Hyd. volume
= 222,614 cuft
Inflow hyd. No.
= 4 - Pond 1 Route
Section type
= Trapezoidal
Reach length
= 3973.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 5.88 ft /s
Routing coeff.
= 0.1970
Modified Att -Kin routing method used
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
0.00
0 4 8
Hyd No. 5
Pond 1 to AP #1
Hyd. No. 5 -- 100 Year
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
I I I I I I I 1 1 0.00
12 16 20 24 28 32 36 40 44 48 52
Hyd No. 4 Time (hrs)

v
0
U
C
r
O
a.
r
O
z
i
O
a.
T c-
O O
-0
0 Lo 0 N — O
fJ W
r Cl) N O
O
W O aC C)
(D
_0 Cl) n OC)
o a—>i
ED W
P N
03 C)
C)
O (/)
ui -D
U)
ri Q>
o fz Q>
O f�,
oo a iJ
eg O O Z3
Co S
O O W
(D N M O
C) W M 00 O
=>
O N m W
U M J f0) Cl)
— > O Q w > CC
O O > 0— C
O
CD > O
O 3 O D
vU vU C
O
3 L)
a�
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LLI Z
N •
N
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`a
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cri
•in
is
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i�
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oL

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 1 - Pond 1
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 382.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
382.00
4,170
0
0
1.00
383.00
5,115
4,634
4,634
2.00
384.00
6,050
5,575
10,209
3.00
385.00
7,316
6,672
16,882
4.00
386.00
8,616
7,956
24,838
5.00
387.00
9,497
9,052
33,890
6.00
388.00
10,438
9,963
43,853
7.00
389.00
11,439
10,934
54,786
8.00
390.00
12,495
11,962
66,748
9.00
391.00
13,611
13,048
79,796
10.00
392.00
14,792
14,196
93,992
11.00
393.00
16,039
15,410
109,402
12.00
394.00
17,354
16,691
126,092
13.00
395.00
18,736
18,039
144,131
Culvert / Orifice Structures
Weir Structures
[A]
[B] [C]
[PrfRsr]
[A]
[B]
[C]
[D]
Rise (in)
= 18.00
4.00 4.00
0.00
Crest Len (ft)
= 12.56
30.00
0.00
0.00
Span (in)
= 18.00
4.00 4.00
0.00
Crest El. (ft)
= 392.00
393.00
0.00
0.00
No. Barrels
= 1
1 1
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft) = 382.00
382.00 391.00 0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 100.00
0.50 0.50
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 8.00
1.00 1.00
n/a
N -Value
= .013
.013 .013
n/a
Orifice Coeff. = 0.60
0.60 0.60
0.60
Exfil.(in /hr)
= 0.000 (by Contour)
Multi -Stage
= n/a
Yes Yes
No
TW Elev. (ft)
= 0.00
Note: Culvert/Orifice
outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers
checked for orifice conditions
(ic) and submergence (s).
Stage / Storage / Discharge
Table
Stage
Storage Elevation
Clv A
Clv B
Clv C
PrfRsr Wr A
Wr B
Wr C
Wr D
Exfil User
Total
ft
cuft ft
cfs
cfs
cfs
cfs cfs
cfs
cfs
cfs
cfs cfs
cfs
0.00
0 382.00
0.00
0.00
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.000
1.00
4,634 383.00
0.36 is
0.36 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.361
2.00
10,209 384.00
0.55 is
0.54 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.545
3.00
16,882 385.00
0.69 is
0.68 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.683
4.00
24,838 386.00
0.80 is
0.80 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.798
5.00
33,890 387.00
0.93 is
0.90 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.899
6.00
43,853 388.00
1.02 is
0.99 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.991
7.00
54,786 389.00
1.07 is
1.07 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
1.074
8.00
66,748 390.00
1.16 is
1.15 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
1.153
9.00
79,796 391.00
1.26 is
1.23 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
1.225
10.00
93,992 392.00
1.71 is
1.29 is
0.38 is
- -- 0.00
0.00
- --
- --
- -- - --
1.673
11.00
109,402 393.00
26.95 is
0.20 is
0.20 is
- -- 26.56s
0.00
- --
- --
- -- - --
26.95
12.00
126,092 394.00
28.49 is
0.08 is
0.08 is
- -- 28.34s
60.00
- --
- --
- -- - --
88.49
13.00
144.131 395.00
29.76 is
0.04 is
0.04 is
- -- 29.61
s 169.71
- --
- --
- -- - --
199.41

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 1
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 48 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = 12 ft
Cross - Sectional Area = 12.57 ft2
Volume of Riser = 150.80 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 9,410 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 18 819 Ibs.
Concrete Base Design:
Length = 6.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 6.0 ft
Height = 4.0 ft
Concrete Base Total Weight = 21,600 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

1109 -001 Laurel Grove
Pond 1
Existinq Channel Dimensions:
I
height = 9.00 ft
0.5 :1 1 :1
width = 0 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.026
ft/ft
Channel Design Calculations:
Channel Area=
60.75
ftZ
Wetted Perimeter (@ 0,„a )=
22.79
ft
Vmm in Channel=
13.20
ft/sec (Assuming full -depth flow)
Q10 (post development):
1.60
cfs
Maximum Flow in Channel:
801.71
cfs
*
CHANNEL IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
I
height =
0.875 ft
0.5 :1
1 :1
width =
0 ft
Flow Area=
0.57
ft2
Wetted Perimeter (@ Cho)=
2.22
ft
Quo Associated with Flow Depth:
1.60
cfs
V10 in Channel=
2.79
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.88 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.026 channel gradient in ft/ft
T < 4.0 = Class I Rip -Rap
T =
1.42 Ib /sgft
T < 8.0 = Class 11 Rip Rap

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Developed Watershed: AP -2 to Pond 2
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
Product
of
CN x Area
N
N
M
�
N
L
'a.,
�
N
L
2)
LL
3.26
319.48
--
Impervious -Road
98
3.59
351.82
--
Impervious - Sidewalk
98
0.63
61.74
--
Impervious - Driveway
98
0.88
86.24
B
Open Space -Lawn -Good Condition
61
4.22
257.42
C
Open Space -Lawn -Good Condition
74
0.24
17.76
D
Open Space -Lawn -Good Condition
80
9.87
789.60
Use only one CN value source per line. Totals =
22.69
1884.06
( 0.03545 sq mi)
CN (weighted) - total product - 1884.06 83
total area 22.69 Use CN -
--
Impervious -Roof
98
3.26
319.48
--
Impervious -Road
98
3.59
351.82
--
Impervious - Sidewalk
98
0.63
61.74
--
Impervious - Driveway
98
0.88
86.24
B
Open Space -Lawn -Good Condition
61
4.22
257.42
C
Open Space -Lawn -Good Condition
74
0.24
17.76
D
Open Space -Lawn -Good Condition
80
9.87
789.60
Use only one CN value source per line. Totals =
22.69
1884.06

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 7
Post Area to Pond 2
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 22.690 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.00 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00 ' '
0 2 4
Hyd No. 7
Post Area to Pond 2
Hyd. No. 7 -- 1 Year
Wednesday, 01 / 7 / 2015
= 41.34 cfs
= 12.03 hrs
= 116,167 cuft
= 83
= Oft
= 14.40 min
= Type II
= 484
Q (cfs)
50.00
40.00
30.00
20.00
10.00
' 0.00
6 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. 7
Post Area to Pond 2
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 22.690 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 7
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 2
Hyd. No. 7 -- 2 Year
Wednesday, 01 / 7 / 2015
53.25 cfs
12.03 hrs
149,253 cuft
83
Oft
14.40 min
Type II
484
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
' ' ' ' - ' 0.00
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. 7
Post Area to Pond 2
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 22.690 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
100.00
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 7
Post Area to Pond 2
Hyd. No. 7 -- 10 Year
Wednesday, 01 / 7 / 2015
= 92.88 cfs
= 12.03 hrs
= 262,175 cuft
= 83
= Oft
= 14.40 min
= Type II
= 484
Q (cfs)
100.00
90.00
80.00
70.00
50.00
40.00
30.00
20.00
10.00
0.00
6 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. 7
Post Area to Pond 2
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 22.690 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
160.00
140.00
120.00
100.00
:1 11
.1 11
40.00
20.00
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 2
Hyd. No. 7 -- 100 Year
Wednesday, 01 / 7 / 2015
151.01 cfs
12.03 hrs
434,156 cuft
83
Oft
14.40 min
Type II
484
Q (cfs)
160.00
140.00
120.00
100.00
:1 11
.1 11
40.00
20.00
0.00 ' ' ' ' ' ' ' ' 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 7 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 8
Pond 2 Route
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 7 - Post Area to Pond 2
Max. Elevation
Reservoir name
= Pond 2
Max. Storage
Storage Indication method used.
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 8
Pond 2 Route
Hyd. No. 8 -- 1 Year
Wednesday, 02 / 18 / 2015
= 12.35 cfs
= 12.30 hrs
= 116,149 cuft
= 373.69 ft
= 42,394 cuft
6 8 10 12 14 16 18 20 22 24
Hyd No. 7 011111 Total storage used = 42,394 cuft
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 8
Pond 2 Route
Hydrograph type
= Reservoir
Peak discharge
= 16.08 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.27 hrs
Time interval
= 2 min
Hyd. volume
= 149,235 cuft
Inflow hyd. No.
= 7 - Post Area to Pond 2
Max. Elevation
= 374.56 ft
Reservoir name
= Pond 2
Max. Storage
= 54,452 cuft
Storage Indication method used.
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00 ' '
0 2 4
Hyd No. 8
6 8 10
Hyd No. 7
Pond 2 Route
Hyd. No. 8 -- 2 Year
12
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
' ' 0.00
14 16 18 20 22 24 26
Time (hrs)
011111 Total storage used = 54,452 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 8
Pond 2 Route
Hydrograph type
= Reservoir
Peak discharge
= 23.77 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.30 hrs
Time interval
= 2 min
Hyd. volume
= 262,157 cuft
Inflow hyd. No.
= 7 - Post Area to Pond 2
Max. Elevation
= 377.22 ft
Reservoir name
= Pond 2
Max. Storage
= 99,958 cuft
Storage Indication method used.
Q (cfs)
100.00
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 8
Pond 2 Route
Hyd. No. 8 -- 10 Year
Q (cfs)
100.00
90.00
80.00
70.00
50.00
40.00
30.00
20.00
10.00
0.00
6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 7 1111111 Total storage used = 99,958 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 8
Pond 2 Route
Hydrograph type
= Reservoir
Peak discharge
= 137.76 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.10 hrs
Time interval
= 2 min
Hyd. volume
= 434,138 cuft
Inflow hyd. No.
= 7 - Post Area to Pond 2
Max. Elevation
= 378.02 ft
Reservoir name
= Pond 2
Max. Storage
= 115,935 cuft
Storage Indication method used.
Pond 2 Route
Q (cfs) Hyd. No. 8 -- 100 Year Q (cfs)
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0 00
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0 00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 8 Hyd No. 7 1111111 Total storage used = 115,935 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 9
Pond 2 to AP #1
Hydrograph type
= Reach
Peak discharge
= 11.27 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.50 hrs
Time interval
= 2 min
Hyd. volume
= 115,987 cuft
Inflow hyd. No.
= 8 - Pond 2 Route
Section type
= Trapezoidal
Reach length
= 3216.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 5.04 ft /s
Routing coeff.
= 0.2075
Modified Att -Kin routing method used.
Q (cfs)
14.00
12.00
10.00
. IM
4.00
2.00
0.00 '
0 2 4
Hyd No. 9
0
Pond 2 to AP #1
Hyd. No. 9 -- 1 Year
Q (cfs)
14.00
12.00
10.00
4.00
f►a[iIi�
i i--.dov I I I I I I I 0.00
8 10 12 14 16 18 20 22 24 26 28
Hyd No. 8 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 9
Pond 2 to AP #1
Hydrograph type
= Reach
Peak discharge
= 15.02 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.50 hrs
Time interval
= 2 min
Hyd. volume
= 149,074 cuft
Inflow hyd. No.
= 8 - Pond 2 Route
Section type
= Trapezoidal
Reach length
= 3216.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 5.30 ft /s
Routing coeff.
= 0.2168
Modified Att -Kin routing method used.
Q (cfs)
18.00
15.00
12.00
3.00
0.00 '
0 2 4
Hyd No. 9
Pond 2 to AP #1
Hyd. No. 9 -- 2 Year
Q (cfs)
18.00
15.00
12.00
3.00
i i I I I I I I 1 0.00
6 8 10 12 14 16 18 20 22 24 26
Hyd No. 8 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 9
Pond 2 to AP #1
Hydrograph type
= Reach
Peak discharge
= 22.92 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.53 hrs
Time interval
= 2 min
Hyd. volume
= 261,996 cuft
Inflow hyd. No.
= 8 - Pond 2 Route
Section type
= Trapezoidal
Reach length
= 3216.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 5.70 ft /s
Routing coeff.
= 0.2314
Modified Att -Kin routing method used.
Q (cfs)
24.00
20.00
16.00
12.00
: IM
4.00
0.00 ' '
0 2 4
Hyd No. 9
Pond 2 to AP #1
Hyd. No. 9 -- 10 Year
Q (cfs)
24.00
20.00
16.00
12.00
4.00
i I I I I I I I I --,r 0.00
6 8 10 12 14 16 18 20 22 24 26
Hyd No. 8 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 9
Pond 2 to AP #1
Hydrograph type = Reach Peak discharge
Storm frequency = 100 yrs Time to peak
Time interval = 2 min Hyd. volume
Inflow hyd. No. = 8 - Pond 2 Route Section type
Reach length = 3216.0 ft Channel slope
Manning's n = 0.024 Bottom width
Side slope = 2.0:1 Max. depth
Rating curve x = 4.101 Rating curve m
Ave. velocity = 7.92 ft /s Routing coeff.
Wednesday, 02 / 18 / 2015
= 101.50 cfs
= 12.20 hrs
= 433,977 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.3077
Modified Att -Kin routing method used.
Q (cfs)
Pond 2 to AP #1
Hyd. No. 9 -- 100 Year
Q (cfs)
140.00
140.00
120.00
120.00
100.00
100.00
80.00
80.00
60.00
60.00
40.00
40.00
20.00
20.00
0.00
0 2 4 6 8 10
Hyd No. 9 Hyd No. 8
0.00
12 14 16 18 20 22 24 26
Time (hrs)

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Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 3 - Pond 2
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 369.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
369.00
5,383
0
0
1.00
370.00
6,847
6,100
6,100
2.00
371.00
8,401
7,610
13,710
3.00
372.00
10,036
9,205
22,915
4.00
373.00
11,745
10,878
33,793
5.00
374.00
13,528
12,625
46,418
6.00
375.00
15,386
14,446
60,864
7.00
376.00
17,320
16,342
77,206
8.00
377.00
19,327
18,313
95,518
9.00
378.00
21,396
20,351
115,869
10.00
379.00
23,528
22,451
138,320
Culvert / Orifice Structures
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Weir Structures
Storage / Discharge Table
[A]
[B]
[C]
[PrfRsr]
Storage
[A]
[B]
[C]
[D]
Rise (in)
= 24.00
12.00
12.00
0.00
Crest Len (ft)
= 18.85
100.00
0.00
0.00
Span (in)
= 24.00
12.00
12.00
0.00
Crest El. (ft)
= 377.25
377.39
0.00
0.00
No. Barrels
= 1
1
2
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft)
= 369.00
369.00
372.50
0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 71.00
0.50
0.50
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 0.70
1.00
1.00
n/a
33,793
373.00
8.15 oc
6.24 is
1.89 is
N -Value
= .013
.013
.013
n/a
46,418
374.00
13.87 oc
6.30 is
7.56 is
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by
Wet area)
6.91 is
10.69 is
Multi -Stage
= n/a
Yes
Yes
No
TW Elev. (ft)
= 0.00
20.58 oc
7.48 is
13.10 is
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B Wr C
Wr D Exfil User Total
ft
cult
ft
cfs
cfs
cfs
cfs
cfs
cfs cfs
cfs cfs cfs cfs
0.00
0
369.00
0.00
0.00
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.000
1.00
6,100
370.00
2.30 is
2.30 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 2.301
2.00
13,710
371.00
4.05 is
4.05 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 4.052
3.00
22,915
372.00
5.35 is
5.35 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 5.348
4.00
33,793
373.00
8.15 oc
6.24 is
1.89 is
- --
0.00
0.00 - --
- -- - -- - -- 8.128
5.00
46,418
374.00
13.87 oc
6.30 is
7.56 is
- --
0.00
0.00 - --
- -- - -- - -- 13.87
6.00
60,864
375.00
17.60 oc
6.91 is
10.69 is
- --
0.00
0.00 - --
- -- - -- - -- 17.60
7.00
77,206
376.00
20.58 oc
7.48 is
13.10 is
- --
0.00
0.00 - --
- -- - -- - -- 20.58
8.00
95,518
377.00
23.14 oc
8.02 is
15.12 is
- --
0.00
0.00 - --
- -- - -- - -- 23.14
9.00
115,869
378.00
41.74 is
2.34 is
4.68 is
- --
34.71 s
95.29 - --
- -- - -- - -- 137.03
10.00
138,320
379.00
45.25 is
0.84 is
1.67 is
- --
42.72s
408.58 - --
- -- - -- - -- 453.81

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 2
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 72 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 28.27 ft2
Volume of Riser = 254.47 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 15,879 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 31 758 Ibs.
Concrete Base Design:
Length = 8.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 8.0 ft
Height = 4.0 ft
Concrete Base Total Weight = 38,400 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

Ownership and Property Information
SCM Name
BMP #2 Level Spreader
Legal Names of Owners of Property
Owner One
Legal Name of Owner
RFII -FH Sierra, LLC
Legal Business Address of Owner
2840 Plaza Place — Suite 360
Name of Local Owner Contact
Andrew Lineberry
E -mail for Local Owner Contact
lineberry @foreverhomellc.com
Phone Number for Local Owner Contact
(919) 870 -9711
Ext.
Owner Two
Legal Name of Owner
Legal Business Address of Owner
Name of Local Owner Contact
E -mail for Local Owner Contact
Phone Number for Local Owner Contact
Ext.
PIN /s on which SCM is Located
0769 -01 -29 -3411
Parcel ID /s on which SCM is Located
193301
DB /s and PG /s for Property on which
SCM is Located
007543/000243
PB /s and PG /s for Property on which
SCM is Located
0000000 /0000000
Coordinates for the Top of the Riser
or Control Structure (North Carolina
State Plane Coordinates, NAD 83)
Easting: 2062096.08
Northing: 799238.14

TSS Removal:
❑ Required ® Not Required
Required
TSS Loading into SCM
TSS Loading out of
TSS Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
Click here
Data Not
Data Not
Data Not
Data Not
Data Not
Data Not
Click here
to enter
Readily
Readily
Readily
Readily
Readily
Readily
to enter
text.
Available at
Available at
Available at
Available at
Available at
Available at this
text.
this Time
this Time
this Time
this Time
this Time
Time
TN Removal:
® Required ❑ Not Required
Required
TN Loading into SCM
TN Loading out of
TN Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
30%
1.36
121.17
1.21
86.00
0.15
35.17
29.03%
TP Removal:
® Required ❑ Not Required
Required
TP Loading into SCM
TP Loading out of
TP Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
lb /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
35%
0.41
36.76
0.17
12.03
0.24
24.73
67.27%
Bacteria Removal: ❑ Required ® Not Required

SCM Drainage Area Characteristics
ELEMENT
CD
As -Built
Drainage Areas (acres)
22.69
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Total Drainage Area to the SCM (acres)
22.69
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Post Transportation I - NCDOT Streets (acres)
0
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Post Transportation I - City Streets (acres)
3.59
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Post Transportation I - Other (acres)
0
Click here to enter text.
Post Non - Transportation I (acres)
4.77
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Post Managed Pervious - HSG B (acres)
4.22
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Post Managed Pervious - HSG C (acres)
0.24
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Post Managed Pervious - HSG D (acres)
9.87
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Post Wooded Pervious - HSG B (acres)
0
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Post Wooded Pervious - HSG C (acres)
0
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Post Wooded Pervious - HSG D (acres)
0
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Total Drainage Area Imperviousness to SCM ( %)
36.9%
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Post Unit Loading, w /out Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP
Post Unit Loading, w/ Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP

SCM Vital Statistics
ELEMENT
CD
As -Built
Invert Elevation of Flow - Splitter Structure (ft
368.50
Click here to enter text.
above MSL)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
Invert Elevation of the Connection to the Forebay
368.50
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(ft)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
Invert Elevation of the Bypass Weir (ft)
370.87
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Width of Blind Swale- Linear Wetland (ft)
8.5'
Click here to enter text.
Length of level Spreader Lip (ft)
100'
Click here to enter text.
Type of Vegetated Filter Strip (VFS): A: 50 -ft
B
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Riparian Area; B: 30 -ft Engineered Filter Strip
[EFS]; or C: 20 -ft EFS + 50 -ft Restored Riparian
Buffer
Slope of VFS in the Direction of Flow ( %)
5.00%
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Type of Bypass System: Natural Draw (ND),
Constructed Bypass
Click here to enter text.
Constructed Bypass Channel (CBC), or
Channel
Constructed Bypass Pipe (CBP)
Peak Flow Rate Directed to Level Spreader (cfs)
10.00 cfs
Click here to enter text.
Peak Flow Rate (10 -yr Storm) Directed to Bypass
13.77 cfs
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System (cfs)
Estimates, Sureties, Etc.
Engineer's Estimate (EE) of Probable Cost to Construct Facility ($)
TBD
Fund Payment Amount (As Applicable): 25% of EE ($)
TBD
[A] Annual O &M Costs ($)
TBD
[B] Annual Certification Costs ($)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
TBD
[D] Annualized Major Repair and Replacement Costs: 1/3 [A] ($)
TBD
[E] Total Annualized Maintenance Costs: [C] + [D] ($)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
TBD
Annual O &M and Certification Funds (Residential Only) to be Set Aside
by Agreement: [C] ($)
TBD

Annual Major Repair and Replacement Funds (Residential Only) to be Set
Aside by Agreement: [D] ($)

1109 -001 Laurel Grove
Pond 2 Bypass
Bypass Channel Dimensions:
I
height = 1.00 ft
3 :1 3 :1
width = 3 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.11
ft/ft
Channel Design Calculations:
Channel Area=
6.00
ftZ
Wetted Perimeter (@ 0,„a )=
9.32
ft
Vmm in Channel=
10.52
ft/sec (Assuming full -depth flow)
Q10 (post development):
13.77
cfs
Maximum Flow in Channel:
63.14
cfs
*
CHANNEL
IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
I
height =
0.458 ft
3 :1
3 :1
width =
3 ft
Flow Area=
2.00
ft2
Wetted Perimeter (@ Cho)=
5.90
ft
Quo Associated with Flow Depth:
13.77
cfs
V10 in Channel=
6.87
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.46 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.11 channel gradient in ft/ft
T < 3.3 = Class I Rip -Rap
T =
3.15 Ib /sgft
T < 8.0 = Class 11 Rip Rap

PHIEDENS
LAND CORP
ENGINEERING - DEVELOPMENT
Inlet / Outlet Calculations
Project: Laurel Grove
Pipe: Pond 2 Flow Splitter
Design By: Adam Lynch
Date: 2/18/15
Check Inlet Control
Hw;c = Hw /D x D, where: Hw /D = 1.5 (from Chart 2)
D= 18 in 1.50 ft
Hw;c = 2.25 ft
Check Outlet Control
Hwoc = ho + H - Lso
ho = dc+ D where: dc = critical depth (from chart 16) = 1.25
2 D= 2 f
1.375
H = head loss in pipe = 1.0 + Ke + 29n2L x VG
81.33 2g
1 (from chart 9)
LSD = length of pipe x slope of pipe
= 1 f x 1.00%
= 0.01
HwOC = 2.37 ft
Hwoc > Hwic - Outlet Control
Hw = 2.37 ft Bypass elevation from bottom of flowsplitter

�j
CHART
2
180
10.000
(2�
(3}
Ise
8,000
EXAMPLE
I56
6.000
fl•ty ;ncna (3.5 trs�}
g
5,000
0 -e20 e4
3.
144
5.
4,000
2!1 ' wyf
132
o ts.
S'
4.
3,000
((] x -5 as
4.
Iz0
(2) 2.1
2,000
105,
96
1,000
3.
54
600
500
72
400
!
3
2.
=
300*
i
1.5
1.5
x
cr
60
n
200
p..
(.5
?
z
/
w
X
0
54
0
48
by
100
>
Q
80
:z
a
U
a
60
-
W
1.0
I.0
42
v
0
50 iiYY -SCALE ENTRANCE
1.0
40
0 TYPE
cc
w
9
1.-
36
30
(1) saaars adze 17th
or
S
33
n
- Q
Q
20
IZ) Greess and Wish
30
healaall
r
8
13) Grosse sal
'S
�nlsc�ia0
27
10
-7
.7-
24
5
.7
6
To use scale (2) or (31 praj.ct
2 ]
5
hari=■e12117 to scale li],issa
4
"a■ slydght laelinsl 11as thrasOh
are 0 !tail$, M r$►srsa h
�6
s
3
iillllralae.
.6
,
IB
2
,S
.3
i.0
1z
HEADWATER DEPTH
'FOR
CONCRETE 'PIPE CULVERTS
lIEAQM'AFER
SCALES 2�3
REvISM MAY 1964 WITH
MLET
CONTROL
evwc•u
v► ►w«c "AD$ -A&K m"
WR -2 4. :-

u-
0
I
w L
Q s
Of
a I:
=F
to I
c
-2000
-1000
800
-600
-500
•400
-300
-ZOO
N
w
x
U
-100 z
10
a
60 cc
LO
50 F
LU
.40
a
0
-30
-20
.10
.8
-6
- 5 .
-4
CHART 3
-12
BUREAU OF PUBLIC ROADS JAN. 196.)
5 -32
-.4
-.6
-.6
-1.0
-2
-3
-4
-5
-s
-8
-10
-20
HEAD FOR
CONCRETE PIPE CULVERTS
FLOWING FULL
n = 0.012
I f H
H W
Slay. Sow
z
a=
z
-
SUBMERGED OUTLET CULVERT FLOWING FULL
J
-�
HW • H. ho-1,50
12O
For oullal clown nal submarj4c% [Ompu4 HW 5y
method■ daacn bad in Ina Eraipn procaEUra
- IOB
-96
A
µ•O9 i
84
72
/
66
O
Cry
r
w
60
�i a
w
ti
-54
/ O ". ��
z
L *110
48'
0.48
-
i
_ -
- -- *x.0.5
00
"0
42
w
�QO
x
6100
36
SOP•
- 3 3
500
C
k00
r
-30
500 �
-27
f •
. 0
o
-24
-21
-18
-15
-12
BUREAU OF PUBLIC ROADS JAN. 196.)
5 -32
-.4
-.6
-.6
-1.0
-2
-3
-4
-5
-s
-8
-10
-20
HEAD FOR
CONCRETE PIPE CULVERTS
FLOWING FULL
n = 0.012

2 --
I
2.
1.5`
0
CHART 16
de CANNOT EXCEED TOP OF PIPE
0 10 20 30 40 50 60 70 80 90 100
DISCHARGE-Q -CFS
6
5
H-
w
w
4
v
2
E-
a 3
w
a
U 2
8
7
H
w
b w
u..
v
.p
M
5 r
CL
w
Q
Q
0 100 200 300 400 500 600 700 BOO 900 1000 U
DISCHARGE -Q -CFS t
U U
12
8 --
I !
6 I I CANNOT EXCEED TOP OF PIPE
3`
1P
9' DIA.
40 1000 2000 3000 4000
DISCHARGE -0 -CFS
BUREAU OF PUBLIC ROADS „
JAN.1964 CRITICAL DEPTH
5 -30, CIRCULAR PIPE

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Qeveloped Watershed: AP -3 to Pond 3
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Ac res
Sq. Ft.
%
Product
of
CN x Area
N
m
.c
N
a,
LL
N
LL
--
Impervious - Roof
98
1.36
133.28
--
Impervious - Road
98
2.02
197.96
--
Impervious - Sidewalk
98
0.46
45.08
--
Impervious - Driveway
98
0.18
17.64
B
Open Space - Lawn - Good Condition
61
1.79
109.19
D
Open Space - Lawn - Good Condition
80
4.82
385.60
' Use only one CN value source per line. Totals = 10.63 888.75
( 0.01661 sq mi)
CN (weighted) = total product = 888.75 Use CN = 84
total area 10.63

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 11
Post Area to Pond 3
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 10.640 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
21.00
18.00
15.00
12.00
• 11
MM
3.00
0.00 '
0 2 4
Hyd No. 11
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 3
Hyd. No. 11 -- 1 Year
Wednesday, 01 / 7 / 2015
18.68 cfs
12.07 hrs
58,564 cuft
84
Oft
17.90 min
Type II
484
Q (cfs)
21.00
18.00
15.00
12.00
• 11
9M IX
3.00
''' ' ' ' ' 0.00
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. 11
Post Area to Pond 3
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 10.640 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
24.00
20.00
16.00
12.00
M
4.00
0.00
0 2 4
Hyd No. 11
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 3
Hyd. No. 11 -- 2 Year
Wednesday, 01 / 7 / 2015
23.92 cfs
12.07 hrs
74,793 cuft
84
Oft
17.90 min
Type II
484
Q (cfs)
24.00
20.00
16.00
12.00
4.00
T 1 1 1 1 1 1 r\. 1 0.00
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. 11
Post Area to Pond 3
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 10.640 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00 ' '
0 2 4
Hyd No. 11
Post Area to Pond 3
Hyd. No. 11 -- 10 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 41.27 cfs
= 12.07 hrs
= 129,852 cuft
= 84
= Oft
= 17.90 min
= Type II
= 484
Q (cfs)
50.00
40.00
30.00
20.00
10.00
- ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 11
Post Area to Pond 3
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 10.640 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
70.00
50.00
FA�
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 11
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 3
Hyd. No. 11 -- 100 Year
Wednesday, 01 / 7 / 2015
66.60 cfs
12.07 hrs
213,233 cuft
84
Oft
17.90 min
Type II
484
Q (cfs)
70.00
50.00
40.00
30.00
20.00
10.00
- ' 0.00
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
Wednesday, 02 / 18 / 2015
Hyd. No. 12
Pond 3 Route
Hydrograph type
= Reservoir
Peak discharge
= 1.944 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.87 hrs
Time interval
= 2 min
Hyd. volume
= 58,550 cuft
Inflow hyd. No.
= 11 - Post Area to Pond 3
Max. Elevation
= 376.83 ft
Reservoir name
= Pond 3
Max. Storage
= 27,636 cuft
Storage Indication method used.
Pond 3 Route
Q (cfs) Hyd. No. 12 -- 1 Year Q (cfs)
21.00 21.00
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Time (hrs)
Hyd No. 12 Hyd No. 11 1111111 Total storage used = 27,636 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 12
Pond 3 Route
Hydrograph type
= Reservoir
Peak discharge
= 3.583 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.57 hrs
Time interval
= 2 min
Hyd. volume
= 74,778 cuft
Inflow hyd. No.
= 11 - Post Area to Pond 3
Max. Elevation
= 377.59 ft
Reservoir name
= Pond 3
Max. Storage
= 34,594 cuft
Storage Indication method used.
Q (cfs)
24.00
20.00
16.00
12.00
m
4.00
0.00
0 2 4
Hyd No. 12
Pond 3 Route
Hyd. No. 12 -- 2 Year
6 8 10 12 14 16 18 20 22 24 26
Hyd No. 11 1111111 Total storage used = 34,594 cuft
Q (cfs)
24.00
20.00
16.00
12.00
4.00
---� 0.00
28
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 12
Pond 3 Route
Hydrograph type
= Reservoir
Peak discharge
= 6.842 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.47 hrs
Time interval
= 2 min
Hyd. volume
= 129,838 cuft
Inflow hyd. No.
= 11 - Post Area to Pond 3
Max. Elevation
= 379.85 ft
Reservoir name
= Pond 3
Max. Storage
= 60,242 cuft
Storage Indication method used.
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 12
Pond 3 Route
Hyd. No. 12 -- 10 Year
6 8 10 12
Hyd No. 11
14 16 18 20 22 24 26
011111 Total storage used = 60,242 cuft
Q (cfs)
50.00
40.00
30.00
20.00
10.00
--- 0.00
28
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 12
Pond 3 Route
Hydrograph type
= Reservoir
Peak discharge
= 45.17 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.20 hrs
Time interval
= 2 min
Hyd. volume
= 213,219 cuft
Inflow hyd. No.
= 11 - Post Area to Pond 3
Max. Elevation
= 381.00 ft
Reservoir name
= Pond 3
Max. Storage
= 76,346 cuft
Storage Indication method used.
Q (cfs)
70.00
50.00
FA�
30.00
20.00
10.00
0.00 ' '
0 2 4
Hyd No. 12
0
Pond 3 Route
Hyd. No. 12 -- 100 Year
Q (cfs)
70.00
50.00
40.00
30.00
20.00
10.00
' ' ' 0.00
8 10 12 14 16 18 20 22 24 26 28
Time (hrs)
Hyd No. 11 011111 Total storage used = 76,346 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 13
Pond 3 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 12 - Pond 3 Route
Section type
Reach length
= 2803.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.57 ft /s
Routing coeff.
Modified Att -Kin routing method used.
Pond 3 to AP #1
Q (cfs) Hyd. No. 13 -- 1 Year
2.00
1.00
W 1 11 �
Wednesday, 02 / 18 / 2015
= 1.935 cfs
= 13.13 hrs
= 58,422 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1717
4 8 12 16 20 24 28
Hyd No. 13 Hyd No. 12
Q (cfs)
2.00
1.00
-MEI_ 0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 13
Pond 3 to AP #1
Hydrograph type
= Reach
Peak discharge
= 3.452 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.83 hrs
Time interval
= 2 min
Hyd. volume
= 74,650 cuft
Inflow hyd. No.
= 12 - Pond 3 Route
Section type
= Trapezoidal
Reach length
= 2803.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 4.00 ft /s
Routing coeff.
= 0.1906
Modified Att -Kin routing method used
Q (cfs)
4.00
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 13
Pond 3 to AP #1
Hyd. No. 13 -- 2 Year
6 8 10 12 14
Hyd No. 12
16
Q (cfs)
4.00
3.00
2.00
1.00
0.00
18 20 22 24 26 28
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 13
Pond 3 to AP #1
Hydrograph type
= Reach
Peak discharge
= 6.602 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.67 hrs
Time interval
= 2 min
Hyd. volume
= 129,710 cuft
Inflow hyd. No.
= 12 - Pond 3 Route
Section type
= Trapezoidal
Reach length
= 2803.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 4.51 ft /s
Routing coeff.
= 0.2125
Modified Att -Kin routing method used.
Q (cfs)
7.00
. IM
5.00
4.00
3.00
2.00
1.00
0.00 ' '
0 2 4
Hyd No. 13
0
Pond 3 to AP #1
Hyd. No. 13 -- 10 Year
Q (cfs)
7.00
5.00
4.00
3.00
2.00
1.00
�- I I I I I I I I I -f 0.00
8 10 12 14 16 18 20 22 24 26 28
Hyd No. 12 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 13
Pond 3 to AP #1
Hydrograph type
= Reach
Peak discharge
= 36.85 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.33 hrs
Time interval
= 2 min
Hyd. volume
= 213,091 cuft
Inflow hyd. No.
= 12 - Pond 3 Route
Section type
= Trapezoidal
Reach length
= 2803.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 6.43 ft /s
Routing coeff.
= 0.2896
Modified Att -Kin routing method used
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 13
Pond 3 to AP #1
Hyd. No. 13 -- 100 Year
6 8 10 12
Hyd No. 12
14 16
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
18 20 22 24 26 28
Time (hrs)

v
0
U
C
lcI
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QI
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(/ > 0
" F-
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cc
Ir LL
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0 0 0 0 0 0 �!
0 0 0 0 0 0
W co v N O m in
I i I i I i I i I i I i I� •��
OL

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 5 - Pond 3
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 372.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
372.00
3,212
0
0
1.00
373.00
4,117
3,655
3,655
2.00
374.00
5,134
4,616
8,270
3.00
375.00
6,266
5,690
13,961
4.00
376.00
7,504
6,875
20,836
5.00
377.00
8,849
8,166
29,002
6.00
378.00
10,294
9,561
38,563
7.00
379.00
11,812
11,043
49,607
8.00
380.00
13,400
12,596
62,203
9.00
381.00
15,057
14,219
76,422
10.00
382.00
16,783
15,911
92,333
Culvert / Orifice Structures
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Weir Structures
Storage / Discharge Table
[A]
[B]
[C]
[PrfRsr]
Storage
[A]
[B]
[C]
[D]
Rise (in)
= 18.00
6.00
10.00
0.00
Crest Len (ft)
= 12.56
30.00
0.00
0.00
Span (in)
= 18.00
6.00
10.00
0.00
Crest El. (ft)
= 379.85
380.50
0.00
0.00
No. Barrels
= 1
1
1
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft)
= 372.00
372.00
376.83
0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 78.00
0.50
0.50
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 3.85
1.00
1.00
n/a
20,836
376.00
1.77 is
1.74 is
0.00
N -Value
= .013
.013
.013
n/a
29,002
377.00
2.10 is
1.97 is
0.11 is
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by
Wet area)
2.11 is
2.28 is
Multi -Stage
= n/a
Yes
Yes
No
TW Elev. (ft)
= 0.00
5.76 is
2.27 is
3.48 is
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B Wr C
Wr D Exfil User Total
ft
cult
ft
cfs
cfs
cfs
cfs
cfs
cfs cfs
cfs cfs cfs cfs
0.00
0
372.00
0.00
0.00
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.000
1.00
3,655
373.00
0.76 is
0.75 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.745
2.00
8,270
374.00
1.17 is
1.17 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 1.166
3.00
13,961
375.00
1.48 is
1.48 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 1.482
4.00
20,836
376.00
1.77 is
1.74 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 1.744
5.00
29,002
377.00
2.10 is
1.97 is
0.11 is
- --
0.00
0.00 - --
- -- - -- - -- 2.084
6.00
38,563
378.00
4.42 is
2.11 is
2.28 is
- --
0.00
0.00 - --
- -- - -- - -- 4.390
7.00
49,607
379.00
5.76 is
2.27 is
3.48 is
- --
0.00
0.00 - --
- -- - -- - -- 5.752
8.00
62,203
380.00
9.12 is
2.33 is
4.36 is
- --
2.43
0.00 - --
- -- - -- - -- 9.122
9.00
76,422
381.00
24.29 is
0.30 is
0.82 is
- --
23.17s
21.21 - --
- -- - -- - -- 45.50
10.00
92,333
382.00
25.85 is
0.13 is
0.37 is
- --
25.32s
110.23 - --
- -- - -- - -- 136.05

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 3
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 48 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 12.57 ft2
Volume of Riser = 113.10 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 7,057 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 14 115 Ibs.
Concrete Base Design:
Length = 6.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 6.0 ft
Height = 3.0 ft
Concrete Base Total Weight = 16,200 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

1109 -001 Laurel Grove
Pond 3
Existinq Channel Dimensions:
I
height = 3.00 ft
3 :1 4.5 :1
width = 0 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.13
ft/ft
Channel Design Calculations:
Channel Area=
33.75
ftZ
Wetted Perimeter (@ 0,„a )=
23.32
ft
Vmm in Channel=
19.64
ft/sec (Assuming full -depth flow)
Q10 (post development):
6.84
cfs
Maximum Flow in Channel:
662.89
cfs
*
CHANNEL
IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
t
height =
0.54 ft
3 :1
4.5 :1
width =
0 ft
Flow Area=
1.09
ft2
Wetted Perimeter (@ Cho)=
4.19
ft
Quo Associated with Flow Depth:
6.84
cfs
V10 in Channel=
6.26
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.54 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.13 channel gradient in ft/ft
T < 4.0 = Class I Rip -Rap
T =
4.38 Ib /sgft
T < 8.0 = Class 11 Rip Rap

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Qeveloped Watershed: AP -4 to Pond 4
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Ac res
Sq. Ft.
%
Product
of
CN x Area
N
m
.c
N
a,
LL
N
LL
--
Impervious - Roof
98
0.88
86.24
--
Impervious - Road
98
2.61
255.78
--
Impervious - Sidewalk
98
0.87
85.26
--
Impervious - Driveway
98
0.18
17.64
--
Impervious - Parking Lot
98
0.79
77.42
D
Open Space - Lawn - Good Condition
80
7.86
628.80
' Use only one CN value source per line. Totals = 13.19 1151.14
( 0.02061 sq mi)
CN (weighted) = total product _ 1151.14 Use CN - 87
total area 13.19

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 15
Post Area to Pond 4
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 13.190 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
0.00
0 2 4
Hyd No. 15
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 4
Hyd. No. 15 -- 1 Year
Wednesday, 01 / 7 / 2015
28.93 cfs
12.03 hrs
81,186 cuft
87
Oft
15.00 min
Type II
484
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
'r ' ' ' ' - ' 0.00
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. 15
Post Area to Pond 4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 13.190 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.50 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
40.00
30.00
20.00
10.00
0.00 '
0 2 4
Hyd No. 15
Post Area to Pond 4
Hyd. No. 15 -- 2 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 36.17 cfs
= 12.03 hrs
= 101,881 cuft
= 87
= Oft
= 15.00 min
= Type II
= 484
Q (cfs)
40.00
30.00
20.00
10.00
- ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 15
Post Area to Pond 4
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 13.190 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00 '
0 2 4
Hyd No. 15
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 4
Hyd. No. 15 -- 10 Year
Wednesday, 01 / 7 / 2015
59.65 cfs
12.03 hrs
170,932 cuft
87
Oft
15.00 min
Type II
484
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
' ' ' ' - ' 0.00
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. 15
Post Area to Pond 4
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 100 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 13.190 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 7.40 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
100.00
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 15
Post Area to Pond 4
Hyd. No. 15 -- 100 Year
Wednesday, 01 / 7 / 2015
= 93.37 cfs
= 12.03 hrs
= 273,872 cuft
= 87
= Oft
= 15.00 min
= Type II
= 484
Q (cfs)
100.00
90.00
80.00
70.00
50.00
40.00
30.00
20.00
10.00
0.00
6 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
Wednesday, 02 / 18 / 2015
Hyd. No. 16
Pond 4 Route
Hydrograph type
= Reservoir
Peak discharge
= 0.946 cfs
Storm frequency
= 1 yrs
Time to peak
= 15.33 hrs
Time interval
= 2 min
Hyd. volume
= 81,157 cuft
Inflow hyd. No.
= 15 - Post Area to Pond 4
Max. Elevation
= 390.50 ft
Reservoir name
= Pond 4
Max. Storage
= 51,173 cuft
Storage Indication method used
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
Pond 4 Route
Hyd. No. 16 -- 1 Year
0.00 ' ' 1 1 '
0 6 12 18 24 30 36 42 48 54
Hyd No. 16 Hyd No. 15 1111111 Total storage used = 51,173 cuft
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
1 0.00
60
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 16
Pond 4 Route
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 15 - Post Area to Pond 4
Max. Elevation
Reservoir name
= Pond 4
Max. Storage
Storage Indication method used.
Q (cfs)
40.00
30.00
20.00
10.00
0.00
0 4 8
Hyd No. 16
Pond 4 Route
Hyd. No. 16 -- 2 Year
Wednesday, 02 / 18 / 2015
= 2.164 cfs
= 13.37 hrs
= 101,852 cuft
= 391.12 ft
= 59,739 cuft
12 16 20 24 28 32 36 40 44 48
Hyd No. 15 1111111 Total storage used = 59,739 cuft
Q (cfs)
40.00
30.00
20.00
10.00
1 0.00
52
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 16
Pond 4 Route
Hydrograph type
= Reservoir
Peak discharge
= 5.541 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.70 hrs
Time interval
= 2 min
Hyd. volume
= 170,903 cuft
Inflow hyd. No.
= 15 - Post Area to Pond 4
Max. Elevation
= 393.25 ft
Reservoir name
= Pond 4
Max. Storage
= 95,096 cuft
Storage Indication method used.
Pond 4 Route
Q (cfs) Hyd. No. 16 -- 10 Year Q (cfs)
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36 40 44 48 52
Time (hrs)
Hyd No. 16 Hyd No. 15 1111111 Total storage used = 95,096 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 16
Pond 4 Route
Hydrograph type
= Reservoir
Peak discharge
= 73.54 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 273,842 cuft
Inflow hyd. No.
= 15 - Post Area to Pond 4
Max. Elevation
= 394.01 ft
Reservoir name
= Pond 4
Max. Storage
= 109,192 cuft
Storage Indication method used.
Q (cfs)
100.00
90.00
80.00
70.00
50.00
40.00
30.00
20.00
0 4
Pond 4 Route
Hyd. No. 16 -- 100 Year
8 12 16 20 24 28 32
Hyd No. 15 1111111 Total storage used = 109,192 cuft
Q (cfs)
100.00
90.00
80.00
70.00
50.00
40.00
30.00
20.00
36
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 17
Pond 4 to AP #1
Hydrograph type
= Reach
Peak discharge
= 0.946 cfs
Storm frequency
= 1 yrs
Time to peak
= 15.63 hrs
Time interval
= 2 min
Hyd. volume
= 80,895 cuft
Inflow hyd. No.
= 16 - Pond 4 Route
Section type
= Trapezoidal
Reach length
= 3490.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.12 ft /s
Routing coeff.
= 0.1237
Modified Att -Kin routing method used.
Q (cfs)
1.00
0.90
0.80
0.70
0.50
0.40
0.30
0.20
0.10
0.00
0 6
Hyd No. 17
Pond 4 to AP #1
Hyd. No. 17 -- 1 Year
12 18 24
Hyd No. 16
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
30 36 42 48 54 60
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 17
Pond 4 to AP #1
Hydrograph type
= Reach
Peak discharge
= 2.140 cfs
Storm frequency
= 2 yrs
Time to peak
= 13.67 hrs
Time interval
= 2 min
Hyd. volume
= 101,591 cuft
Inflow hyd. No.
= 16 - Pond 4 Route
Section type
= Trapezoidal
Reach length
= 3490.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.64 ft /s
Routing coeff.
= 0.1429
Modified Att -Kin routing method used
Q (cfs)
3.00
2.00
1.00
0.00 ' ' y
0 4 8
Hyd No. 17
Pond 4 to AP #1
Hyd. No. 17 -- 2 Year
12 16 20
Hyd No. 16
24 28 32 36 40 44 48
Q (cfs)
3.00
2.00
1.00
--1-1 0.00
52
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 17
Pond 4 to AP #1
Hydrograph type = Reach Peak discharge
Storm frequency = 10 yrs Time to peak
Time interval = 2 min Hyd. volume
Inflow hyd. No. = 16 - Pond 4 Route Section type
Reach length = 3490.0 ft Channel slope
Manning's n = 0.024 Bottom width
Side slope = 2.0:1 Max. depth
Rating curve x = 4.101 Rating curve m
Ave. velocity = 4.34 ft/s Routing coeff.
Wednesday, 02 / 18 / 2015
= 5.366 cfs
= 12.93 hrs
= 170,642 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1681
Modified Att -Kin routing method used.
Q (cfs)
Pond 4 to AP #1
Hyd. No. 17 -- 10 Year
Q (cfs)
6.00
6.00
5.00
5.00
4.00
4.00
3.00
3.00
2.00
2.00
1.00
1.00
0.00
0 4 8 12 16 20 24 28 32 36 40
Hyd No. 17 Hyd No. 16
0.00
44 48 52
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 17
Pond 4 to AP #1
Hydrograph type
= Reach
Peak discharge
= 52.81 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.23 hrs
Time interval
= 2 min
Hyd. volume
= 273,582 cuft
Inflow hyd. No.
= 16 - Pond 4 Route
Section type
= Trapezoidal
Reach length
= 3490.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 7.04 ft /s
Routing coeff.
= 0.2593
Modified Att -Kin routing method used.
Pond 4 to AP #1
Q (cfs) Hyd. No. 17 -- 100 Year Q (cfs)
80.00
80.00
70.00
70.00
60.00
60.00
50.00
50.00
40.00
40.00
30.00
20.00
30.00
20.00
10.00
n nn
10.00
0 00
0 4 8 12 16 20 24 28 32 36
Hyd No. 17 Hyd No. 16
40
Time (hrs)

v
0
U
C
lcI
LL.
rte,
QI
Ql
ICI
LL.
T c-
O a
-0
C N r O
f2 CA
CO a C)
0 N VD
H w v M aC C)
a M o0 N
o n aC>
m LU
0 m� N
O •(D 3 C)
0
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o ri Q>
0
�IO 0 O .)
O W U Za.
N 00M E: CI) S
O O O
U
LL L6 M w f_
00 J
O > M /
O �
o r U
o c
�U I E
cm m
CD > N
o �
U)
c
O
0
01 cn
C
N
O
LL Z
m
N
M
C))
M
N >
N (D
W w
V '
Ca Q
LO .ID
`a
;a
i2
L�
cri
is
s=
to
C)
CL
a�
cq
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U-)
o O C)
0 0 0 0 0 0 CW
0 0 0 0 0 C) ••
W co v CV O m in
OL

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 7 - Pond 4
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 385.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
385.00
5,425
0
0
1.00
386.00
6,721
6,061
6,061
2.00
387.00
8,095
7,397
13,457
3.00
388.00
9,549
8,811
22,269
4.00
389.00
11,082
10,305
32,574
5.00
390.00
12,694
11,878
44,451
6.00
391.00
14,384
13,529
57,980
7.00
392.00
16,151
15,257
73,238
8.00
393.00
17,993
17,062
90,300
9.00
394.00
19,909
18,941
109,241
10.00
395.00
21,901
20,895
130,136
Culvert / Orifice Structures
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Weir Structures
Storage / Discharge Table
[A]
[B]
[C]
[PrfRsr]
Storage
[A]
[B]
[C]
[D]
Rise (in)
= 18.00
4.00
10.00
0.00
Crest Len (ft)
= 12.56
40.00
0.00
0.00
Span (in)
= 18.00
4.00
10.00
0.00
Crest El. (ft)
= 393.26
393.27
0.00
0.00
No. Barrels
= 1
1
1
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft)
= 385.00
385.00
390.49
0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 73.00
0.50
0.50
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 1.40
1.00
1.00
n/a
32,574
389.00
0.80 is
0.80 is
0.00
N -Value
= .013
.013
.013
n/a
44,451
390.00
0.93 is
0.90 is
0.00
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by
Wet area)
0.98 is
0.86 is
Multi -Stage
= n/a
Yes
Yes
No
TW Elev. (ft)
= 0.00
3.80 is
1.04 is
2.75 is
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B Wr C
Wr D Exfil User Total
ft
cult
ft
cfs
cfs
cfs
cfs
cfs
cfs cfs
cfs cfs cfs cfs
0.00
0
385.00
0.00
0.00
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.000
1.00
6,061
386.00
0.36 is
0.36 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.361
2.00
13,457
387.00
0.55 is
0.54 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.545
3.00
22,269
388.00
0.69 is
0.68 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.683
4.00
32,574
389.00
0.80 is
0.80 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.798
5.00
44,451
390.00
0.93 is
0.90 is
0.00
- --
0.00
0.00 - --
- -- - -- - -- 0.899
6.00
57,980
391.00
1.84 is
0.98 is
0.86 is
- --
0.00
0.00 - --
- -- - -- - -- 1.834
7.00
73,238
392.00
3.80 is
1.04 is
2.75 is
- --
0.00
0.00 - --
- -- - -- - -- 3.781
8.00
90,300
393.00
4.94 is
1.10 is
3.80 is
- --
0.00
0.00 - --
- -- - -- - -- 4.904
9.00
109,241
394.00
23.91 is
0.25 is
1.55 is
- --
22.11 s
49.90 - --
- -- - -- - -- 73.81
10.00
130,136
395.00
25.82 is
0.08 is
0.50 is
- --
25.24s
182.04 - --
- -- - -- - -- 207.86

Anti - Flotation Calculation Worksheet ECEN
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 4
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 48 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 12.57 ft2
Volume of Riser = 113.10 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 7,057 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 14 115 Ibs.
Concrete Base Design:
Length = 6.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 6.0 ft
Height = 3.0 ft
Concrete Base Total Weight = 16,200 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

1109 -001 Laurel Grove
Pond 4
Existinq Channel Dimensions:
I
height = 3.00 ft
1.5 :1 2 :1
width = 0 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.15
ft/ft
Channel Design Calculations:
Channel Area=
15.75
ft2
Wetted Perimeter (@ 0,„a )=
12.12
ft
Vmm in Channel=
19.64
ft/sec (Assuming full -depth flow)
Q10 (post development):
5.54
cfs
Maximum Flow in Channel:
309.30
cfs
*
CHANNEL
IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
t
height =
0.664 ft
1.5 :1
2 :1
width =
0 ft
Flow Area=
0.77
ft2
Wetted Perimeter (@ Cho)=
2.68
ft
Quo Associated with Flow Depth:
5.54
cfs
V10 in Channel=
7.19
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.66 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.15 channel gradient in ft/ft
T < 4.0 = Class I Rip -Rap
T =
6.22 Ib /sgft
T < 8.0 = Class 11 Rip Rap

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Qeveloped Watershed: AP -5 to Pond 5
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Ac res
Sq. Ft.
%
Product
of
CN x Area
N
m
.c
N
a,
LL
N
LL
--
Impervious - Roof
98
1.65
161.70
--
Impervious - Road
98
0.91
89.18
--
Impervious - Sidewalk
98
0.16
15.68
--
Impervious - Driveway
98
0.46
45.08
B
Open Space - Lawn - Good Condition
61
1.54
93.94
D
Open Space - Lawn - Good Condition
80
2.75
220.00
D
Woods - Good Condition
77
0.73
56.21
' Use only one CN value source per line. Totals = 8.20 681.79
( 0.01281 sq mi)
CN (weighted) = total product _ 681.79 Use CN = 83
total area 8.20

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 19
Post Area to Pond 5
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 8.200 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
18.00
15.00
12.00
3.00
0.00 '
0 2 4
Hyd No. 19
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 5
Hyd. No. 19 -- 1 Year
Wednesday, 01 / 7 / 2015
17.09 cfs
12.00 hrs
44,404 cuft
83
Oft
10.60 min
Type II
484
Q (cfs)
18.00
15.00
12.00
11111M
3.00
' ' ' 0.00
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. 19
Post Area to Pond 5
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 8.200 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
24.00
20.00
16.00
12.00
M
4.00
0.00 '
0 2 4
Hyd No. 19
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 5
Hyd. No. 19 -- 2 Year
Wednesday, 01 / 7 / 2015
22.01 cfs
12.00 hrs
57,051 cuft
83
Oft
10.60 min
Type II
484
Q (cfs)
24.00
20.00
16.00
12.00
4.00
"'' ' ' ' 0.00
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. 19
Post Area to Pond 5
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 8.200 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 19
Post Area to Pond 5
Hyd. No. 19 -- 10 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 38.35 cfs
= 12.00 hrs
= 100,214 cuft
= 83
= Oft
= 10.60 min
= Type II
= 484
Q (cfs)
40.00
30.00
20.00
10.00
- ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 19
Post Area to Pond 5
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 8.200 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
70.00
50.00
FA�
30.00
20.00
10.00
0.00 '
0 2 4
Hyd No. 19
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 5
Hyd. No. 19 -- 100 Year
Wednesday, 01 / 7 / 2015
62.30 cfs
12.00 hrs
165,953 cuft
83
Oft
10.60 min
Type II
484
Q (cfs)
70.00
50.00
40.00
30.00
20.00
10.00
-' ' ' ' I I 1 0.00
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 Wednesday, 02 / 18 / 2015
Hyd. No. 20
Route to Pond 5
Hydrograph type
= Reservoir
Peak discharge
= 1.001 cfs
Storm frequency
= 1 yrs
Time to peak
= 13.43 hrs
Time interval
= 2 min
Hyd. volume
= 44,375 cuft
Inflow hyd. No.
= 19 - Post Area to Pond 5
Max. Elevation
= 366.73 ft
Reservoir name
= Pond 5
Max. Storage
= 23,549 cuft
Storage Indication method used.
Q (cfs)
18.00
15.00
12.00
3.00
0.00
0 4
Hyd No. 20
Route to Pond 5
Hyd. No. 20 -- 1 Year
8 12 16 20 24 28 32 36 40
Hyd No. 19 1111111 Total storage used = 23,549 cuft
Q (cfs)
18.00
15.00
12.00
3.00
1 0.00
44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 20
Route to Pond 5
Hydrograph type
= Reservoir
Peak discharge
= 1.139 cfs
Storm frequency
= 2 yrs
Time to peak
= 13.60 hrs
Time interval
= 2 min
Hyd. volume
= 57,021 cuft
Inflow hyd. No.
= 19 - Post Area to Pond 5
Max. Elevation
= 367.44 ft
Reservoir name
= Pond 5
Max. Storage
= 31,551 cuft
Storage Indication method used.
Route to Pond 5
Q (cfs) Hyd. No. 20 -- 2 Year Q (cfs)
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36 40 44
Time (hrs)
Hyd No. 20 Hyd No. 19 1111111 Total storage used = 31,551 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 20
Route to Pond 5
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 19 - Post Area to Pond 5
Max. Elevation
Reservoir name
= Pond 5
Max. Storage
Storage Indication method used.
Q (cfs)
40.00
30.00
20.00
10.00
0.00
0 4
Hyd No. 20
Route to Pond 5
Hyd. No. 20 -- 10 Year
Wednesday, 02 / 18 / 2015
= 14.54 cfs
= 12.20 hrs
= 100,185 cuft
= 368.57 ft
= 45,629 cuft
8 12 16 20 24 28 32
Hyd No. 19 1111111 Total storage used = 45,629 cuft
Q (cfs)
40.00
30.00
20.00
10.00
---� 0.00
36
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 20
Route to Pond 5
Hydrograph type
= Reservoir
Peak discharge
= 56.92 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 165,923 cuft
Inflow hyd. No.
= 19 - Post Area to Pond 5
Max. Elevation
= 369.01 ft
Reservoir name
= Pond 5
Max. Storage
= 51,457 cuft
Storage Indication method used.
Q (cfs)
70.00
50.00
FA�
30.00
20.00
10.00
Route to Pond 5
Hyd. No. 20 -- 100 Year
0.00 '
0 4 8 12
Hyd No. 20 Hyd No. 19
16 20 24 28
011111 Total storage used = 51,457 cuft
Q (cfs)
70.00
50.00
40.00
30.00
20.00
10.00
—'-1 0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 21
Pond 5 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 20 - Route to Pond 5
Section type
Reach length
= 2617.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.15 ft/s
Routing coeff.
Modified Att -Kin routing method used.
Q (cfs)
2.00
1.00
W 1 11 �
4 8
Hyd No. 21
Pond 5 to AP #1
Hyd. No. 21 -- 1 Year
12 16 20
Hyd No. 20
Wednesday, 02 / 18 / 2015
= 1.001 cfs
= 13.67 hrs
= 44,110 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1632
24 28 32 36 40
Q (cfs)
2.00
1.00
-EEL- 0.00
44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 21
Pond 5 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 20 - Route to Pond 5
Section type
Reach length
= 2617.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.23 ft /s
Routing coeff.
Modified Att -Kin routing method used.
Q (cfs)
2.00
1.00
0.00
0 4
Hyd No. 21
Pond 5 to AP #1
Hyd. No. 21 -- 2 Year
8 12 16
Hyd No. 20
Wednesday, 02 / 18 / 2015
= 1.139 cfs
= 13.83 hrs
= 56,757 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1668
20 24 28 32 36 40
Q (cfs)
2.00
1.00
—1+- 0.00
44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 21
Pond 5 to AP #1
Hydrograph type
= Reach
Peak discharge
= 10.52 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.30 hrs
Time interval
= 2 min
Hyd. volume
= 99,920 cuft
Inflow hyd. No.
= 20 - Route to Pond 5
Section type
= Trapezoidal
Reach length
= 2617.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 5.20 ft /s
Routing coeff.
= 0.2558
Modified Att -Kin routing method used.
Q (cfs)
15.00
12.00
. IM
3.00
0.00
0 4
Hyd No. 21
Pond 5 to AP #1
Hyd. No. 21 -- 10 Year
8 12 16
Hyd No. 20
20 24 28 32
Q (cfs)
15.00
12.00
M
3.00
---11 0.00
36
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 21
Pond 5 to AP #1
Hydrograph type
= Reach
Peak discharge
= 44.23 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.17 hrs
Time interval
= 2 min
Hyd. volume
= 165,659 cuft
Inflow hyd. No.
= 20 - Route to Pond 5
Section type
= Trapezoidal
Reach length
= 2617.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 6.71 ft /s
Routing coeff.
= 0.3184
Modified Att -Kin routing method used
Pond 5 to AP #1
Q (cfs) Hyd. No. 21 -- 100 Year Q (cfs)
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36
Time (hrs)
Hyd No. 21 Hyd No. 20

v
0
U
C
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IQI
LL.
(�1
QI
Ql
IQI
LL.
Q r
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cri
ca
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OD
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0
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()
i)
CL

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 9 - Pond 5
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 364.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
364.00
6,805
0
0
1.00
365.00
8,081
7,433
7,433
2.00
366.00
9,421
8,742
16,175
3.00
367.00
10,824
10,113
26,288
4.00
368.00
12,880
11,836
38,124
5.00
369.00
13,813
13,342
51,466
6.00
370.00
15,397
14,596
66,063
Culvert / Orifice Structures Weir Structures
[A]
[B] [C]
[PrfRsr]
[A]
[B]
[C]
[D]
Rise (in)
= 24.00
5.00 Inactive
0.00
Crest Len (ft)
= 12.54
50.00
0.00
0.00
Span (in)
= 24.00
5.00 8.00
0.00
Crest El. (ft)
= 368.10
368.57
0.00
0.00
No. Barrels
= 1
1 1
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft) = 364.00
364.00 365.17
0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 46.00
0.50 0.50
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 1.09
1.00 1.00
n/a
N -Value
= .013
.013 .013
n/a
Orifice Coeff. = 0.60
0.60 0.60
0.60
Exfil.(in /hr)
= 0.000 (by Wet area)
Multi -Stage
= n/a
Yes Yes
No
TW Elev. (ft)
= 0.00
Note: Culvert/Orifice
outflows are analyzed
under inlet (ic) and outlet (oc) control. Weir risers
checked for orifice conditions
(ic) and submergence (s).
Stage / Storage / Discharge
Table
Stage
Storage Elevation
Clv A
Clv B
Clv C
PrfRsr Wr A
Wr B
Wr C
Wr D
ExfiI User
Total
ft
cuft ft
cfs
cfs
cfs
cfs cfs
cfs
cfs
cfs
cfs cfs
cfs
0.00
0 364.00
0.00
0.00
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.000
1.00
7,433 365.00
0.56 is
0.55 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.552
2.00
16,175 366.00
0.84 is
0.84 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
0.839
3.00
26,288 367.00
1.07 is
1.06 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
1.056
4.00
38,124 368.00
1.26 is
1.24 is
0.00
- -- 0.00
0.00
- --
- --
- -- - --
1.237
5.00
51,466 369.00
28.80 is
0.40 is
0.00
- -- 28.40s
28.20
- --
- --
- -- - --
56.99
6.00
66.063 370.00
33.62 is
0.16 is
0.00
- -- 33.44s
171.00
- --
- --
- -- - --
204.60

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 5
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 48 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 12.57 ft2
Volume of Riser = 62.83 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 3,921 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 7 841 Ibs.
Concrete Base Design:
Length = 6.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 6.0 ft
Height = 2.0 ft
Concrete Base Total Weight = 10,800 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

1109 -001 Laurel Grove
Pond 5
Existinq Channel Dimensions:
I
height = 1.00 ft
4.5 :1 5 :1
width = 0 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.11
ft/ft
Channel Design Calculations:
Channel Area=
4.75
ft'
Wetted Perimeter (@ 0,„a )=
9.71
ft
Vmm in Channel=
8.77
ft/sec (Assuming full -depth flow)
Q10 (post development):
14.54
cfs
Maximum Flow in Channel:
41.64
cfs
*
CHANNEL
IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
I
height =
0.674 ft
4.5 :1
5 :1
width =
0 ft
Flow Area=
2.16
ft2
Wetted Perimeter (@ Cho)=
6.54
ft
Quo Associated with Flow Depth:
14.54
cfs
V10 in Channel=
6.74
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.67 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.11 channel gradient in ft/ft
T < 4.0 = Class I Rip -Rap
T =
4.63 Ib /sgft
T < 8.0 = Class 11 Rip Rap

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Developed Watershed: AP -6 to Pond 6
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
Product
of
CN x Area
N
N
M
�
N
L
'a.,
�
N
L
2)
LL
1.24
121.52
--
Impervious -Road
98
2.88
282.24
--
Impervious - Sidewalk
98
0.95
93.10
--
Impervious - Driveway
98
0.45
44.10
B
Open Space -Lawn -Good Condition
61
2.43
148.23
D
Open Space -Lawn -Good Condition
80
2.78
222.40
Use only one CN value source per line. Totals =
10.73
911.59
( 911.59 Use CN 0.01677 sq mi)
CN (weighted) = total product _ = 85
total area 10.73
--
Impervious -Roof
98
1.24
121.52
--
Impervious -Road
98
2.88
282.24
--
Impervious - Sidewalk
98
0.95
93.10
--
Impervious - Driveway
98
0.45
44.10
B
Open Space -Lawn -Good Condition
61
2.43
148.23
D
Open Space -Lawn -Good Condition
80
2.78
222.40
Use only one CN value source per line. Totals =
10.73
911.59

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 23
Post Area to Ponds 6
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 10.720 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
24.00
20.00
16.00
12.00
M
4.00
0.00 '
0 2 4
Hyd No. 23
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Ponds 6
Hyd. No. 23 -- 1 Year
Wednesday, 01 / 7 / 2015
21.50 cfs
12.03 hrs
60,259 cuft
85
Oft
15.00 min
Type II
484
Q (cfs)
24.00
20.00
16.00
12.00
4.00
"'— ' ' ' 1 1 1 77=1- ' 0.00
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. 23
Post Area to Ponds 6
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 10.720 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
28.00
24.00
20.00
16.00
12.00
1I
4.00
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Ponds 6
Hyd. No. 23 -- 2 Year
Wednesday, 01 / 7 / 2015
27.27 cfs
12.03 hrs
76,503 cuft
85
Oft
15.00 min
Type II
484
Q (cfs)
28.00
24.00
20.00
16.00
12.00
Ki 11
4.00
0.00 ' —r ' ' ' I I I 1 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 23 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 23
Post Area to Ponds 6
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 10.720 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 23
Post Area to Ponds 6
Hyd. No. 23 -- 10 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 46.22 cfs
= 12.03 hrs
= 131,297 cuft
= 85
= Oft
= 15.00 min
= Type II
= 484
Q (cfs)
50.00
40.00
30.00
20.00
10.00
- ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 23
Post Area to Ponds 6
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 10.720 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
80.00
70.00
.1 11
50.00
40.00
30.00
20.00
10.00
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Ponds 6
Hyd. No. 23 -- 100 Year
Wednesday, 01 / 7 / 2015
73.69 cfs
12.03 hrs
213,825 cuft
85
Oft
15.00 min
Type II
484
Q (cfs)
80.00
70.00
•1 11
50.00
40.00
30.00
20.00
10.00
0.00 ' ' ' ' ' ' ' 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 23 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 24
Pond 6 Route
Hydrograph type
= Reservoir
Peak discharge
= 2.462 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.63 hrs
Time interval
= 2 min
Hyd. volume
= 60,228 cuft
Inflow hyd. No.
= 23 - Post Area to Ponds 6
Max. Elevation
= 355.71 ft
Reservoir name
= Pond 6
Max. Storage
= 30,646 cuft
Storage Indication method used.
Q (cfs)
24.00
20.00
16.00
12.00
4.00
0.00
0 4 8
Hyd No. 24
Pond 6 Route
Hyd. No. 24 -- 1 Year
12 16 20 24 28 32 36 40
Hyd No. 23 1111111 Total storage used = 30,646 cuft
Q (cfs)
24.00
20.00
16.00
12.00
4.00
1
44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 24
Pond 6 Route
Hydrograph type
= Reservoir
Peak discharge
= 4.042 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.47 hrs
Time interval
= 2 min
Hyd. volume
= 76,472 cuft
Inflow hyd. No.
= 23 - Post Area to Ponds 6
Max. Elevation
= 356.39 ft
Reservoir name
= Pond 6
Max. Storage
= 37,531 cuft
Storage Indication method used.
Pond 6 Route
Q (cfs) Hyd. No. 24 -- 2 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36 40 44
Time (hrs)
Hyd No. 24 Hyd No. 23 1111111 Total storage used = 37,531 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 24
Pond 6 Route
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 23 - Post Area to Ponds 6
Max. Elevation
Reservoir name
= Pond 6
Max. Storage
Storage Indication method used.
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 4
Hyd No. 24
Pond 6 Route
Hyd. No. 24 -- 10 Year
Wednesday, 02 / 18 / 2015
= 31.77 cfs
= 12.17 hrs
= 131,266 cuft
= 357.66 ft
= 51,653 cuft
8 12 16 20 24 28 32
Hyd No. 23 1111111 Total storage used = 51,653 cuft
Q (cfs)
50.00
40.00
30.00
20.00
10.00
--L 0.00
36
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 24
Pond 6 Route
Hydrograph type
= Reservoir
Peak discharge
= 71.86 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 213,794 cuft
Inflow hyd. No.
= 23 - Post Area to Ponds 6
Max. Elevation
= 358.01 ft
Reservoir name
= Pond 6
Max. Storage
= 55,740 cuft
Storage Indication method used.
Pond 6 Route
Q (cfs) Hyd. No. 24 -- 100 Year Q (cfs)
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 24 Hyd No. 23 1111111 Total storage used = 55,740 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 25
Pond 6 to AP #1
Hydrograph type
= Reach
Peak discharge
= 2.459 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.67 hrs
Time interval
= 2 min
Hyd. volume
= 59,945 cuft
Inflow hyd. No.
= 24 - Pond 6 Route
Section type
= Trapezoidal
Reach length
= 550.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.73 ft /s
Routing coeff.
= 0.6669
Modified Att -Kin routing method used
Q (cfs)
3.00
2.00
1.00
0.00 ' '
0 4
Hyd No. 25
Pond 6 to AP #1
Hyd. No. 25 -- 1 Year
8 12 16
Hyd No. 24
20 24 28 32 366 40
Q (cfs)
3.00
2.00
1.00
0.00
44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 25
Pond 6 to AP #1
Hydrograph type = Reach Peak discharge
Storm frequency = 2 yrs Time to peak
Time interval = 2 min Hyd. volume
Inflow hyd. No. = 24 - Pond 6 Route Section type
Reach length = 550.0 ft Channel slope
Manning's n = 0.024 Bottom width
Side slope = 2.0:1 Max. depth
Rating curve x = 4.101 Rating curve m
Ave. velocity = 4.09 ft /s Routing coeff.
Wednesday, 02 / 18 / 2015
= 4.041 cfs
= 12.50 hrs
= 76,190 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.7089
Modified Att -Kin routing method used.
Q (cfs)
Pond 6 to AP #1
Hyd. No. 25 -- 2 Year
Q (cfs)
5.00
5.00
Ah
4.00
4.00
3.00
3.00
2.00
2.00
1.00
0.00
0 4 8
Hyd No. 25
12 16 20
Hyd No. 24
1.00
0.00
24 28 32 36 40 44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 25
Pond 6 to AP #1
Hydrograph type
= Reach
Peak discharge
= 31.56 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.20 hrs
Time interval
= 2 min
Hyd. volume
= 130,984 cuft
Inflow hyd. No.
= 24 - Pond 6 Route
Section type
= Trapezoidal
Reach length
= 550.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 6.02 ft /s
Routing coeff.
= 0.8937
Modified Att -Kin routing method used.
Pond 6 to AP #1
Q (cfs) Hyd. No. 25 -- 10 Year
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
0 4 8 12 16
Hyd No. 25 Hyd No. 24
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
20 24 28 32 36
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 25
Pond 6 to AP #1
Hydrograph type
= Reach
Peak discharge
= 71.80 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.10 hrs
Time interval
= 2 min
Hyd. volume
= 213,513 cuft
Inflow hyd. No.
= 24 - Pond 6 Route
Section type
= Trapezoidal
Reach length
= 550.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 7.01 ft /s
Routing coeff.
= 0.9697
Modified Att -Kin routing method used.
Pond 6 to AP #1
Q (cfs) Hyd. No. 25 -- 100 Year Q (cfs)
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0 00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0 00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 25 Hyd No. 24

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Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 11 - Pond 6
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 352.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
352.00
6,668
0
0
1.00
353.00
7,475
7,067
7,067
2.00
354.00
8,326
7,896
14,963
3.00
355.00
9,223
8,770
23,733
4.00
356.00
10,163
9,688
33,421
5.00
357.00
11,141
10,647
44,068
6.00
358.00
12,155
11,643
55,711
7.00
359.00
13,207
12,676
68,387
Culvert / Orifice Structures
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Weir Structures
Storage / Discharge Table
[A]
[B]
[C]
[PrfRsr]
Elevation
[A]
[B]
[C]
[D]
Rise (in)
= 30.00
4.00
8.00
0.00
Crest Len (ft)
= 18.85
60.00
0.00
0.00
Span (in)
= 30.00
4.00
8.00
0.00
Crest El. (ft)
= 357.10
357.67
0.00
0.00
No. Barrels
= 1
1
2
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft)
= 352.00
352.00
355.12
0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 164.00
0.50
0.50
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 1.83
1.00
1.00
n/a
- -- - -- - -- 3.248
5.00
44,068
357.00
5.10 is
N -Value
= .013
.013
.013
n/a
6.00
55,711
358.00
48.84 is
0.29 is
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by
Wet area)
0.12 is
0.92 is
Multi -Stage
= n/a
Yes
Yes
No
TW Elev. (ft)
= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr Wr A
Wr B Wr C
Wr D ExfiI User Total
ft
cult
ft
cfs
cfs
cfs
cfs cfs
cfs cfs
cfs cfs cfs cfs
0.00
0
352.00
0.00
0.00
0.00
- -- 0.00
0.00 - --
- -- - -- - -- 0.000
1.00
7,067
353.00
0.39 is
0.37 is
0.00
- -- 0.00
0.00 - --
- -- - -- - -- 0.369
2.00
14,963
354.00
0.56 is
0.55 is
0.00
- -- 0.00
0.00 - --
- -- - -- - -- 0.552
3.00
23,733
355.00
0.72 is
0.69 is
0.00
- -- 0.00
0.00 - --
- -- - -- - -- 0.689
4.00
33,421
356.00
3.32 is
0.76 is
2.49 is
- -- 0.00
0.00 - --
- -- - -- - -- 3.248
5.00
44,068
357.00
5.10 is
0.85 is
4.18 is
- -- 0.00
0.00 - --
- -- - -- - -- 5.033
6.00
55,711
358.00
48.84 is
0.29 is
2.33 is
- -- 46.22s
22.75 - --
- -- - -- - -- 71.58
7.00
68,387
359.00
56.30 is
0.12 is
0.92 is
- -- 55.23s
184.06 - --
- -- - -- - -- 240.33

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 6
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 72 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 28.27 ft2
Volume of Riser = 169.65 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 10,586 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 21 172 Ibs.
Concrete Base Design:
Length = 8.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 8.0 ft
Height = 3.0 ft
Concrete Base Total Weight = 28,800 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

Ownership and Property Information
SCM Name
BMP #6 Level Spreader
Legal Names of Owners of Property
Owner One
Legal Name of Owner
RFII -FH Sierra, LLC
Legal Business Address of Owner
2840 Plaza Place — Suite 360
Name of Local Owner Contact
Andrew Lineberry
E -mail for Local Owner Contact
lineberry @foreverhomellc.com
Phone Number for Local Owner Contact
(919) 870 -9711
Ext.
Owner Two
Legal Name of Owner
Legal Business Address of Owner
Name of Local Owner Contact
E -mail for Local Owner Contact
Phone Number for Local Owner Contact
Ext.
PIN /s on which SCM is Located
0769 -01 -29 -3411
Parcel ID /s on which SCM is Located
193301
DB /s and PG /s for Property on which
SCM is Located
007543/000243
PB /s and PG /s for Property on which
SCM is Located
0000000 /0000000
Coordinates for the Top of the Riser
or Control Structure (North Carolina
State Plane Coordinates, NAD 83)
Easting: 2062007.98
Northing: 801064.84

TSS Removal:
❑ Required ® Not Required
Required
TSS Loading into SCM
TSS Loading out of
TSS Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
Click here
Data Not
Data Not
Data Not
Data Not
Data Not
Data Not
Click here
to enter
Readily
Readily
Readily
Readily
Readily
Readily
to enter
text.
Available at
Available at
Available at
Available at
Available at
Available at this
text.
this Time
this Time
this Time
this Time
this Time
Time
TN Removal:
® Required ❑ Not Required
Required
TN Loading into SCM
TN Loading out of
TN Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
30%
1.37
77.95
1.21
54.83
0.16
23.12
29.66%
TP Removal:
® Required ❑ Not Required
Required
TP Loading into SCM
TP Loading out of
TP Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
lb /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
35%
0.53
30.21
0.18
8.06
0.35
22.15
73.32%
Bacteria Removal: ❑ Required ® Not Required

SCM Drainage Area Characteristics
ELEMENT
CD
As -Built
Drainage Areas (acres)
10.73
Click here to enter text.
Total Drainage Area to the SCM (acres)
10.73
Click here to enter text.
Post Transportation I - NCDOT Streets (acres)
0
Click here to enter text.
Post Transportation I - City Streets (acres)
2.88
Click here to enter text.
Post Transportation I - Other (acres)
0
Click here to enter text.
Post Non - Transportation I (acres)
2.64
Click here to enter text.
Post Managed Pervious - HSG B (acres)
2.43
Click here to enter text.
Post Managed Pervious - HSG C (acres)
0
Click here to enter text.
Post Managed Pervious - HSG D (acres)
2.78
Click here to enter text.
Post Wooded Pervious - HSG B (acres)
0
Click here to enter text.
Post Wooded Pervious - HSG C (acres)
0
Click here to enter text.
Post Wooded Pervious - HSG D (acres)
0
Click here to enter text.
Total Drainage Area Imperviousness to SCM ( %)
51.4%
Click here to enter text.
Post Unit Loading, w /out Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP
Post Unit Loading, w/ Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP

SCM Vital Statistics
ELEMENT
CD
As -Built
Invert Elevation of Flow - Splitter Structure (ft
349.00
Click here to enter text.
above MSL)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
Invert Elevation of the Connection to the Forebay
349.00
Click here to enter text.
(ft)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
Invert Elevation of the Bypass Weir (ft)
351.37
Click here to enter text.
Width of Blind Swale- Linear Wetland (ft)
8.5'
Click here to enter text.
Length of level Spreader Lip (ft)
50'
Click here to enter text.
Type of Vegetated Filter Strip (VFS): A: 50 -ft
B
Click here to enter text.
Riparian Area; B: 30 -ft Engineered Filter Strip
[EFS]; or C: 20 -ft EFS + 50 -ft Restored Riparian
Buffer
Slope of VFS in the Direction of Flow ( %)
5.00%
Click here to enter text.
Type of Bypass System: Natural Draw (ND),
Constructed Bypass
Click here to enter text.
Constructed Bypass Channel (CBC), or
Channel
Constructed Bypass Pipe (CBP)
Peak Flow Rate Directed to Level Spreader (cfs)
5.00 cfs
Click here to enter text.
Peak Flow Rate (10 -yr Storm) Directed to Bypass
26.77 cfs
Click here to enter text.
System (cfs)
Estimates, Sureties, Etc.
Engineer's Estimate (EE) of Probable Cost to Construct Facility ($)
TBD
Fund Payment Amount (As Applicable): 25% of EE ($)
TBD
[A] Annual O &M Costs ($)
TBD
[B] Annual Certification Costs ($)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
TBD
[D] Annualized Major Repair and Replacement Costs: 1/3 [A] ($)
TBD
[E] Total Annualized Maintenance Costs: [C] + [D] ($)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
TBD
Annual O &M and Certification Funds (Residential Only) to be Set Aside
by Agreement: [C] ($)
TBD

Annual Major Repair and Replacement Funds (Residential Only) to be Set
Aside by Agreement: [D] ($)

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Monday, 05 / 4 / 2015
Pond No. 21 -
Pond 6 Plunge Pool
Stage
Storage
Elevation
Clv A
Pond Data
Wr D Exfil User Total
ft
tuft
ft
cfs
cfs cfs cfs cfs cfs cfs
cfs cfs cfs cfs
0.00
Contours - User - defined contour areas.
Conic method used for volume calculation. Begining Elevation = 348.00 ft
- --
- -- - -- - -- 0.00 - -- - --
Stage / Storage
Table
499
349.00
- --
- -- - -- - -- 0.00 - -- - --
- -- - -- - -- 0.000
2.00
1,261
Stage (ft)
Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
2,321
351.00
0.00
348.00
- -- - -- - -- 0.000
382
3,750
0
0
- -- - -- - -- 184.60 - -- - --
- -- - -- - -- 184.60
1.00
349.00
626
499
499
2.00
350.00
906
762
1,261
3.00
351.00
1,222
1,060
2,321
4.00
352.00
1,648
1,430
3,750
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrfRsr]
[A] [B]
[C]
[D]
Rise (in)
= 0.00
0.00
0.00
0.00
Crest Len (ft)
= 71.00 0.00
0.00
0.00
Span (in)
= 0.00
0.00
0.00
0.00
Crest El. (ft)
= 351.00 0.00
0.00
0.00
No. Barrels
= 0
0
0
0
Weir Coeff.
= 2.60 3.33
3.33
3.33
Invert El. (ft)
= 0.00
0.00
0.00
0.00
Weir Type
= Broad - --
- --
- --
Length (ft)
= 0.00
0.00
0.00
0.00
Multi -Stage
= No No
No
No
Slope ( %)
= 0.00
0.00
0.00
n/a
N -Value
= .013
.013
.013
n/a
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by Wet area)
Multi -Stage
= n/a
No
No
No
TW Elev. (ft)
= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B Clv C PrfRsr Wr A Wr B Wr C
Wr D Exfil User Total
ft
tuft
ft
cfs
cfs cfs cfs cfs cfs cfs
cfs cfs cfs cfs
0.00
0
348.00
- --
- -- - -- - -- 0.00 - -- - --
- -- - -- - -- 0.000
1.00
499
349.00
- --
- -- - -- - -- 0.00 - -- - --
- -- - -- - -- 0.000
2.00
1,261
350.00
- --
- -- - -- - -- 0.00 - -- - --
- -- - -- - -- 0.000
3.00
2,321
351.00
- --
- -- - -- - -- 0.00 - -- - --
- -- - -- - -- 0.000
4.00
3,750
352.00
- --
- -- - -- - -- 184.60 - -- - --
- -- - -- - -- 184.60

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Monday, 05 / 4 / 2015
Hyd. No. 64
Pond 6 Plunge Pool
Hydrograph type
= Reservoir
Peak discharge
= 31.54 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.17 hrs
Time interval
= 2 min
Hyd. volume
= 128,946 cuft
Inflow hyd. No.
= 24 - Pond 6 Route
Max. Elevation
= 351.32 ft
Reservoir name
= Pond 6 Plunge Pool
Max. Storage
= 2,760 cuft
Storage Indication method used.
Pond 6 Plunge Pool
Elev (ft) Hyd. No. 64 -- 10 Year Elev (ft)
353.00 353.00
352.00 352.00
351.00 351.00
350.00 350.00
349.00 349.00
348.00 348.00
0 4 8 12 16 20 24 28 32 36
Time (hrs)
21. Pond 6 Plunge Pool

PHIEDENS
LAND CORP
ENGINEERING - DEVELOPMENT
Inlet / Outlet Calculations
Project: Laurel Grove
Pipe: Pond 6 Flow Splitter
Design By: Adam Lynch
Date: 5/4/15
Check Inlet Control
Hw;c = Hw /D x D, where: Hw /D = 0.85 (from Chart 2)
D= 18 in= 1.50 ft
Hw;c = 1.28 ft
Check Outlet Control
Hwoc = ho + H - Lso
ho = dc+ D where: dc = critical depth (from chart 16) = 0.85
2 D= 2 f
1.175
H = head loss in pipe = 1.0 + Ke + 29n2L x VG
81.33 2g
1 (from chart 9)
LSD = length of pipe x slope of pipe
= ft x 1.00%
= 0.00
HwOC = 2.17 ft
Hwoc > Hwic - Outlet Control
Hw = 2.17 ft Bypass elevation from bottom of flowsplitter

�j
CHART
2
180
10.000
(2�
(3}
Ise
8,000
EXAMPLE
I56
6.000
fl•ty ;ncna (3.5 trs�}
g
5,000
0 -e20 e4
3.
144
5.
4,000
2!1 ' wyf
132
o ts.
S'
4.
3,000
((] x -5 as
4.
Iz0
(2) 2.1
2,000
105,
96
1,000
3.
54
600
500
72
400
!
3
2.
=
300*
i
1.5
1.5
x
cr
60
n
200
p..
(.5
?
z
/
w
X
0
54
0
48
by
100
>
Q
80
:z
a
U
a
60
-
W
1.0
I.0
42
v
0
50 iiYY -SCALE ENTRANCE
1.0
40
0 TYPE
cc
w
9
1.-
36
30
(1) saaars adze 17th
or
S
33
n
- Q
Q
20
IZ) Greess and Wish
30
healaall
r
8
13) Grosse sal
'S
�nlsc�ia0
27
10
-7
.7-
24
5
.7
6
To use scale (2) or (31 praj.ct
2 ]
5
hari=■e12117 to scale li],issa
4
"a■ slydght laelinsl 11as thrasOh
are 0 !tail$, M r$►srsa h
�6
s
3
iillllralae.
.6
,
IB
2
,S
.3
i.0
1z
HEADWATER DEPTH
'FOR
CONCRETE 'PIPE CULVERTS
lIEAQM'AFER
SCALES 2�3
REvISM MAY 1964 WITH
MLET
CONTROL
evwc•u
v► ►w«c "AD$ -A&K m"
WR -2 4. :-

u-
0
I
w L
Q s
Of
a I:
=F
to I
c
-2000
-1000
800
-600
-500
•400
-300
-ZOO
N
w
x
U
-100 z
10
a
60 cc
LO
50 F
LU
.40
a
0
-30
-20
.10
.8
-6
- 5 .
-4
CHART 3
-12
BUREAU OF PUBLIC ROADS JAN. 196.)
5 -32
-.4
-.6
-.6
-1.0
-2
-3
-4
-5
-s
-8
-10
-20
HEAD FOR
CONCRETE PIPE CULVERTS
FLOWING FULL
n = 0.012
I f H
H W
Slay. Sow
z
a=
z
-
SUBMERGED OUTLET CULVERT FLOWING FULL
J
-�
HW • H. ho-1,50
12O
For oullal clown nal submarj4c% [Ompu4 HW 5y
method■ daacn bad in Ina Eraipn procaEUra
- IOB
-96
A
µ•O9 i
84
72
/
66
O
Cry
r
w
60
�i a
w
ti
-54
/ O ". ��
z
L *110
48'
0.48
-
i
_ -
- -- *x.0.5
00
"0
42
w
�QO
x
6100
36
SOP•
- 3 3
500
C
k00
r
-30
500 �
-27
f •
. 0
o
-24
-21
-18
-15
-12
BUREAU OF PUBLIC ROADS JAN. 196.)
5 -32
-.4
-.6
-.6
-1.0
-2
-3
-4
-5
-s
-8
-10
-20
HEAD FOR
CONCRETE PIPE CULVERTS
FLOWING FULL
n = 0.012

2 --
I
2.
1.5`
0
CHART 16
de CANNOT EXCEED TOP OF PIPE
0 10 20 30 40 50 60 70 80 90 100
DISCHARGE-Q -CFS
6
5
H-
w
w
4
v
2
E-
a 3
w
a
U 2
8
7
H
w
b w
u..
v
.p
M
5 r
CL
w
Q
Q
0 100 200 300 400 500 600 700 BOO 900 1000 U
DISCHARGE -Q -CFS t
U U
12
8 --
I !
6 I I CANNOT EXCEED TOP OF PIPE
3`
1P
9' DIA.
40 1000 2000 3000 4000
DISCHARGE -0 -CFS
BUREAU OF PUBLIC ROADS „
JAN.1964 CRITICAL DEPTH
5 -30, CIRCULAR PIPE

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Developed Watershed: AP -7 to Pond 7
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
Product
of
CN x Area
N
N
M
�
N
L
'a.,
�
N
L
2)
LL
1.44
141.12
--
Impervious -Road
98
1.61
157.78
--
Impervious - Sidewalk
98
0.42
41.16
--
Impervious - Driveway
98
0.56
54.88
B
Open Space -Lawn -Good Condition
61
1.51
92.11
D
Open Space -Lawn -Good Condition
80
3.05
244.00
Use only one CN value source per line. Totals =
8.59
731.05
( 0.01342 sq mi)
CN (weighted) = total product _ 731.05 Use CN = 85
total area 8.59
--
Impervious -Roof
98
1.44
141.12
--
Impervious -Road
98
1.61
157.78
--
Impervious - Sidewalk
98
0.42
41.16
--
Impervious - Driveway
98
0.56
54.88
B
Open Space -Lawn -Good Condition
61
1.51
92.11
D
Open Space -Lawn -Good Condition
80
3.05
244.00
Use only one CN value source per line. Totals =
8.59
731.05

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 27
Post Area to Pond 7
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 8.590 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
18.00
15.00
12.00
3.00
0.00 '
0 2 4
Hyd No. 27
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 7
Hyd. No. 27 -- 1 Year
Wednesday, 01 / 7 / 2015
17.23 cfs
12.03 hrs
48,286 cuft
85
Oft
15.00 min
Type II
484
Q (cfs)
18.00
15.00
12.00
11111M
3.00
-I"- ' ' ' 0.00
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. 27
Post Area to Pond 7
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 8.590 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
24.00
20.00
16.00
12.00
M
4.00
0.00
0 2 4
Hyd No. 27
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 7
Hyd. No. 27 -- 2 Year
Wednesday, 01 / 7 / 2015
21.85 cfs
12.03 hrs
61,302 cuft
85
Oft
15.00 min
Type II
484
Q (cfs)
24.00
20.00
16.00
12.00
4.00
'r- ' ' ' ' - ' 0.00
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. 27
Post Area to Pond 7
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 8.590 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 5.10 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
40.00
30.00
20.00
10.00
0.00 '
0 2 4
Hyd No. 27
Post Area to Pond 7
Hyd. No. 27 -- 10 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 37.04 cfs
= 12.03 hrs
= 105,209 cuft
= 85
= Oft
= 15.00 min
= Type II
= 484
Q (cfs)
40.00
30.00
20.00
10.00
- ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 27
Post Area to Pond 7
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 8.590 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 27
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 7
Hyd. No. 27 -- 100 Year
Wednesday, 01 / 7 / 2015
59.05 cfs
12.03 hrs
171,339 cuft
85
Oft
15.00 min
Type II
484
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
- ' 0.00
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 Wednesday, 02 / 18 / 2015
Hyd. No. 28
Route to Pond 7
Hydrograph type
= Reservoir
Peak discharge
= 0.850 cfs
Storm frequency
= 1 yrs
Time to peak
= 13.90 hrs
Time interval
= 2 min
Hyd. volume
= 49,503 cuft
Inflow hyd. No.
= 27 - Post Area to Pond 7
Max. Elevation
= 361.50 ft
Reservoir name
= Pond 7
Max. Storage
= 28,122 cuft
Storage Indication method used.
Q (cfs)
24.00
20.00
16.00
12.00
4.00
0.00
0 4 8
Hyd No. 28
Route to Pond 7
Hyd. No. 28 -- 1 Year
12 16 20 24 28 32 36 40
Hyd No. 27 011111 Total storage used = 28,122 cuft
Q (cfs)
24.00
20.00
16.00
12.00
4.00
1 0.00
44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 28
Route to Pond 7
Hydrograph type
= Reservoir
Peak discharge
= 0.941 cfs
Storm frequency
= 2 yrs
Time to peak
= 14.10 hrs
Time interval
= 2 min
Hyd. volume
= 62,853 cuft
Inflow hyd. No.
= 27 - Post Area to Pond 7
Max. Elevation
= 362.45 ft
Reservoir name
= Pond 7
Max. Storage
= 37,113 cuft
Storage Indication method used.
Q (cfs)
28.00
24.00
20.00
16.00
12.00
1I
4.00
0.00
0 4 8
Hyd No. 28
Route to Pond 7
Hyd. No. 28 -- 2 Year
Q (cfs)
28.00
24.00
20.00
16.00
12.00
Ki 11
4.00
0.00
12 16 20 24 28 32 36 40 44 48
Time (hrs)
Hyd No. 27 1111111 Total storage used = 37,113 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 28
Route to Pond 7
Hydrograph type
= Reservoir
Peak discharge
= 4.566 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.47 hrs
Time interval
= 2 min
Hyd. volume
= 107,886 cuft
Inflow hyd. No.
= 27 - Post Area to Pond 7
Max. Elevation
= 364.37 ft
Reservoir name
= Pond 7
Max. Storage
= 59,103 cuft
Storage Indication method used
Q (cfs)
50.00
40.00
30.00
20.00
10.00
Route to Pond 7
Hyd. No. 28 -- 10 Year
0.00
0 4 8 12 16 20 24 28 32 36 40 44
Hyd No. 28 Hyd No. 27 1111111 Total storage used = 59,103 cuft
Q (cfs)
50.00
40.00
30.00
20.00
10.00
1 0.00
48
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 28
Route to Pond 7
Hydrograph type
= Reservoir
Peak discharge
= 61.27 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.03 hrs
Time interval
= 2 min
Hyd. volume
= 175,712 cuft
Inflow hyd. No.
= 27 - Post Area to Pond 7
Max. Elevation
= 365.00 ft
Reservoir name
= Pond 7
Max. Storage
= 67,252 cuft
Storage Indication method used.
Q (cfs)
Route to Pond 7
Hyd. No. 28 -- 100 Year
Q (cfs)
ov.uv
80.00
70.00
70.00
60.00
60.00
50.00
50.00
40.00
40.00
30.00
30.00
20.00
20.00
10.00
n nn
10.00
0 00
0 4 8 12 16 20 24 28 32 36
Hyd No. 28 Hyd No. 27 ]7111111 Total storage used = 67,252 cuft
40
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 29
Pond 7 to AP #1
Hydrograph type
= Reach
Peak discharge
= 0.850 cfs
Storm frequency
= 1 yrs
Time to peak
= 13.97 hrs
Time interval
= 2 min
Hyd. volume
= 49,314 cuft
Inflow hyd. No.
= 28 - Route to Pond 7
Section type
= Trapezoidal
Reach length
= 1028.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.05 ft /s
Routing coeff.
= 0.3597
Modified Att -Kin routing method used.
Pond 7 to AP #1
Q (cfs) Hyd. No. 29 -- 1 Year
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0 00
0 4 8
Hyd No. 29
CIA
12 16
Hyd No. 28
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
20 24 28 32 36 40 44
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 29
Pond 7 to AP #1
Hydrograph type
= Reach
Peak discharge
= 0.941 cfs
Storm frequency
= 2 yrs
Time to peak
= 14.20 hrs
Time interval
= 2 min
Hyd. volume
= 62,665 cuft
Inflow hyd. No.
= 28 - Route to Pond 7
Section type
= Trapezoidal
Reach length
= 1028.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.11 ft /s
Routing coeff.
= 0.3654
Modified Att -Kin routing method used.
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0 4 8
Hyd No. 29
Pond 7 to AP #1
Hyd. No. 29 -- 2 Year
12 16 20 24 28 32 36 40 44
Hyd No. 28
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
48
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 29
Pond 7 to AP #1
Hydrograph type
= Reach
Peak discharge
= 4.453 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.57 hrs
Time interval
= 2 min
Hyd. volume
= 107,698 cuft
Inflow hyd. No.
= 28 - Route to Pond 7
Section type
= Trapezoidal
Reach length
= 1028.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 4.18 ft /s
Routing coeff.
= 0.4621
Modified Att -Kin routing method used.
Q (cfs)
5.00
4.00
3.00
2.00
1.00
0.00 ' ' —Opr
0 4 8
Hyd No. 29
Pond 7 to AP #1
Hyd. No. 29 -- 10 Year
Q (cfs)
5.00
4.00
3.00
2.00
1.00
I I I I I I 1 1 _ 0.00
12 16 20 24 28 32 36 40 44 48
Hyd No. 28 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 29
Pond 7 to AP #1
Hydrograph type
= Reach
Peak discharge
= 55.70 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.10 hrs
Time interval
= 2 min
Hyd. volume
= 175,523 cuft
Inflow hyd. No.
= 28 - Route to Pond 7
Section type
= Trapezoidal
Reach length
= 1028.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 6.81 ft /s
Routing coeff.
= 0.6566
Modified Att -Kin routing method used
Pond 7 to AP #1
Q (cfs) Hyd. No. 29 -- 100 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 4 8 12 16 20 24 28 32 36 40
Time (hrs)
Hyd No. 29 Hyd No. 28

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Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 13 - Pond 7
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 357.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
357.00
3,913
0
0
1.00
358.00
4,856
4,376
4,376
2.00
359.00
5,876
5,357
9,733
3.00
360.00
6,984
6,421
16,154
4.00
361.00
8,179
7,573
23,727
5.00
362.00
9,463
8,812
32,540
6.00
363.00
10,835
10,140
42,680
7.00
364.00
12,294
11,556
54,235
8.00
365.00
13,833
13,055
67,290
9.00
366.00
15,452
14,634
81,924
Culvert / Orifice Structures
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Weir Structures
Storage / Discharge Table
[A]
[B]
[C]
[PrfRsr]
Elevation
[A]
[B]
[C]
[D]
Rise (in)
= 18.00
4.00
0.00
0.00
Crest Len (ft)
= 12.54
40.00
0.00
0.00
Span (in)
= 18.00
4.00
0.00
0.00
Crest El. (ft)
= 364.19
364.38
0.00
0.00
No. Barrels
= 1
1
0
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft)
= 357.00
357.00
0.00
0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 65.00
0.50
0.00
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 2.31
1.00
0.00
n/a
- -- - -- - -- 0.798
5.00
32,540
362.00
0.93 is
N -Value
= .013
.013
.013
n/a
6.00
42,680
363.00
1.02 is
0.99 is - --
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by
Wet area)
1.07 is - --
- --
Multi -Stage
= n/a
Yes
No
No
TW Elev. (ft)
= 0.00
0.22 is - --
- --
22.27s
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Civ A
Clv B Clv C
PrfRsr
Wr A
Wr B Wr C
Wr D EAI User Total
ft
cuft
ft
cfs
cfs cfs
cfs
cfs
cfs cfs
cfs cfs cfs cfs
0.00
0
357.00
0.00
0.00 - --
- --
0.00
0.00 - --
- -- - -- - -- 0.000
1.00
4,376
358.00
0.36 is
0.36 is - --
- --
0.00
0.00 - --
- -- - -- - -- 0.361
2.00
9,733
359.00
0.55 is
0.54 is - --
- --
0.00
0.00 - --
- -- - -- - -- 0.545
3.00
16,154
360.00
0.69 is
0.68 is - --
- --
0.00
0.00 - --
- -- - -- - -- 0.683
4.00
23,727
361.00
0.80 is
0.80 is - --
- --
0.00
0.00 - --
- -- - -- - -- 0.798
5.00
32,540
362.00
0.93 is
0.90 is - --
- --
0.00
0.00 - --
- -- - -- - -- 0.899
6.00
42,680
363.00
1.02 is
0.99 is - --
- --
0.00
0.00 - --
- -- - -- - -- 0.991
7.00
54,235
364.00
1.07 is
1.07 is - --
- --
0.00
0.00 - --
- -- - -- - -- 1.074
8.00
67,290
365.00
22.49 is
0.22 is - --
- --
22.27s
39.05 - --
- -- - -- - -- 61.54
9.00
81,924
366.00
24.39 is
0.07 is - --
- --
24.31 s
164.95 - --
- -- - -- - -- 189.33

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 7
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 48 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 12.57 ft2
Volume of Riser = 100.53 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 6,273 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 12 546 Ibs.
Concrete Base Design:
Length = 6.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 6.0 ft
Height = 3.0 ft
Concrete Base Total Weight = 16,200 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

Ownership and Property Information
SCM Name
BMP #7 Level Spreader
Legal Names of Owners of Property
Owner One
Legal Name of Owner
RFII -FH Sierra, LLC
Legal Business Address of Owner
2840 Plaza Place — Suite 360
Name of Local Owner Contact
Andrew Lineberry
E -mail for Local Owner Contact
lineberry @foreverhomellc.com
Phone Number for Local Owner Contact
(919) 870 -9711
Ext.
Owner Two
Legal Name of Owner
Legal Business Address of Owner
Name of Local Owner Contact
E -mail for Local Owner Contact
Phone Number for Local Owner Contact
Ext.
PIN /s on which SCM is Located
0769 -01 -29 -3411
Parcel ID /s on which SCM is Located
193301
DB /s and PG /s for Property on which
SCM is Located
007543/000243
PB /s and PG /s for Property on which
SCM is Located
0000000 /0000000
Coordinates for the Top of the Riser
or Control Structure (North Carolina
State Plane Coordinates, NAD 83)
Easting: 2061625.38
Northing: 800877.64

TSS Removal:
❑ Required ® Not Required
Required
TSS Loading into SCM
TSS Loading out of
TSS Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
Click here
Data Not
Data Not
Data Not
Data Not
Data Not
Data Not
Click here
to enter
Readily
Readily
Readily
Readily
Readily
Readily
to enter
text.
Available at
Available at
Available at
Available at
Available at
Available at this
text.
this Time
this Time
this Time
this Time
this Time
Time
TN Removal:
® Required ❑ Not Required
Required
TN Loading into SCM
TN Loading out of
TN Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
30%
1.34
56.17
1.21
40.28
0.13
15.89
28.29%
TP Removal:
® Required ❑ Not Required
Required
TP Loading into SCM
TP Loading out of
TP Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
lb /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
35%
0.44
18.21
0.17
5.75
0.27
12.46
68.42%
Bacteria Removal: ❑ Required ® Not Required

SCM Drainage Area Characteristics
ELEMENT
CD
As -Built
Drainage Areas (acres)
8.59
Click here to enter text.
Total Drainage Area to the SCM (acres)
8.59
Click here to enter text.
Post Transportation I - NCDOT Streets (acres)
0
Click here to enter text.
Post Transportation I - City Streets (acres)
1.61
Click here to enter text.
Post Transportation I - Other (acres)
0
Click here to enter text.
Post Non - Transportation I (acres)
2.42
Click here to enter text.
Post Managed Pervious - HSG B (acres)
1.51
Click here to enter text.
Post Managed Pervious - HSG C (acres)
0
Click here to enter text.
Post Managed Pervious - HSG D (acres)
3.09
Click here to enter text.
Post Wooded Pervious - HSG B (acres)
0
Click here to enter text.
Post Wooded Pervious - HSG C (acres)
0
Click here to enter text.
Post Wooded Pervious - HSG D (acres)
0
Click here to enter text.
Total Drainage Area Imperviousness to SCM ( %)
46.9%
Click here to enter text.
Post Unit Loading, w /out Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP
Post Unit Loading, w/ Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP

SCM Vital Statistics
ELEMENT
CD
As -Built
Invert Elevation of Flow - Splitter Structure (ft
355.5
Click here to enter text.
above MSL)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
Invert Elevation of the Connection to the Forebay
355.5
Click here to enter text.
(ft)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
Invert Elevation of the Bypass Weir (ft)
n/a
Click here to enter text.
Width of Blind Swale- Linear Wetland (ft)
8.5'
Click here to enter text.
Length of level Spreader Lip (ft)
46'
Click here to enter text.
Type of Vegetated Filter Strip (VFS): A: 50 -ft
B
Click here to enter text.
Riparian Area; B: 30 -ft Engineered Filter Strip
[EFS]; or C: 20 -ft EFS + 50 -ft Restored Riparian
Buffer
Slope of VFS in the Direction of Flow ( %)
5.00%
Click here to enter text.
Type of Bypass System: Natural Draw (ND),
Not Required
Click here to enter text.
Constructed Bypass Channel (CBC), or
Constructed Bypass Pipe (CBP)
Peak Flow Rate Directed to Level Spreader (cfs)
4.57 cfs
Click here to enter text.
Peak Flow Rate (10 -yr Storm) Directed to Bypass
0 cfs
Click here to enter text.
System (cfs)
Estimates, Sureties, Etc.
Engineer's Estimate (EE) of Probable Cost to Construct Facility ($)
TBD
Fund Payment Amount (As Applicable): 25% of EE ($)
TBD
[A] Annual O &M Costs ($)
TBD
[B] Annual Certification Costs ($)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
TBD
[D] Annualized Major Repair and Replacement Costs: 1/3 [A] ($)
TBD
[E] Total Annualized Maintenance Costs: [C] + [D] ($)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
TBD
Annual O &M and Certification Funds (Residential Only) to be Set Aside
by Agreement: [C] ($)
TBD

Annual Major Repair and Replacement Funds (Residential Only) to be Set
Aside by Agreement: [D] ($)

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 05/04/15
Location: Checked: Date:
Circle one: Present Developed Watershed: AP -8 to Pond 8
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
Product
of
CN x Area
N
N
M
�
N
L
'a.,
�
N
L
2)
LL
0.73
71.54
--
Impervious -Road
98
0.73
71.54
--
Impervious - Sidewalk
98
0.15
14.70
--
Impervious - Driveway
98
0.19
18.62
B
Open Space -Lawn -Good Condition
61
1.71
104.31
D
Open Space -Lawn -Good Condition
80
1.75
140.00
Use only one CN value source per line. Totals =
5.26
420.71
( 0.00822 sq mi)
CN (weighted) = total product 80
total area 5.26 420.71 Use CN _ =
--
Impervious -Roof
98
0.73
71.54
--
Impervious -Road
98
0.73
71.54
--
Impervious - Sidewalk
98
0.15
14.70
--
Impervious - Driveway
98
0.19
18.62
B
Open Space -Lawn -Good Condition
61
1.71
104.31
D
Open Space -Lawn -Good Condition
80
1.75
140.00
Use only one CN value source per line. Totals =
5.26
420.71

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 31
Post Area to Pond 8
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 5.270 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.00 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
10.00
M
4.00
2.00
0.00 ' '
0 2 4
Hyd No. 31
Post Area to Pond 8
Hyd. No. 31 -- 1 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 8.208 cfs
= 12.03 hrs
= 23,315 cuft
= 80
= Oft
= 15.00 min
= Type II
= 484
Q (cfs)
10.00
11111M
4.00
2.00
0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 31
Post Area to Pond 8
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 5.270 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
12.00
10.00
4.00
2.00
0.00 ' '
0 2 4
Hyd No. 31
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 8
Hyd. No. 31 -- 2 Year
Wednesday, 01 / 7 / 2015
10.84 cfs
12.03 hrs
30,521 cuft
80
Oft
15.00 min
Type II
484
Q (cfs)
12.00
10.00
4.00
2.00
.&-� ' ' ' ' 0.00
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. 31
Post Area to Pond 8
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 5.270 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
21.00
18.00
15.00
12.00
• 11
MM
3.00
0.00 '
0 2 4
Hyd No. 31
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 8
Hyd. No. 31 -- 10 Year
Wednesday, 01 / 7 / 2015
19.80 cfs
12.03 hrs
55,588 cuft
80
Oft
15.00 min
Type II
484
Q (cfs)
21.00
18.00
15.00
12.00
• 11
9M IX
3.00
"r ' ' ' I I 1 0.00
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. 31
Post Area to Pond 8
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 5.270 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00 '
0 2 4
Hyd No. 31
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 8
Hyd. No. 31 -- 100 Year
Wednesday, 01 / 7 / 2015
33.22 cfs
12.03 hrs
94,470 cuft
80
Oft
15.00 min
Type II
484
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
-' ' ' ' 0.00
10 12 14 16 18 20 22 24 26
Time (hrs)

1
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 32
Route to Pond 8
Hydrograph type
= Reservoir
Peak discharge
= 3.494 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.20 hrs
Time interval
= 2 min
Hyd. volume
= 24,659 cuft
Inflow hyd. No.
= 31 - Post Area to Pond 8
Max. Elevation
= 359.11 ft
Reservoir name
= Pond 8
Max. Storage
= 5,631 cuft
Storage Indication method used.
Q (cfs)
10.00
M
4.00
2.00
0.00 '
0 2 4
Hyd No. 32
Route to Pond 8
Hyd. No. 32 -- 1 Year
6 8 10
Hyd No. 31
12
Q (cfs)
10.00
4.00
2.00
' ' ' 0.00
14 16 18 20 22 24 26
Time (hrs)
011111 Total storage used = 5,631 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 32
Route to Pond 8
Hydrograph type
= Reservoir
Peak discharge
= 3.797 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.23 hrs
Time interval
= 2 min
Hyd. volume
= 32,281 cuft
Inflow hyd. No.
= 31 - Post Area to Pond 8
Max. Elevation
= 359.93 ft
Reservoir name
= Pond 8
Max. Storage
= 8,500 cuft
Storage Indication method used.
Q (cfs)
14.00
12.00
10.00
. m
4.00
2.00
0.00 '
0 2 4
Hyd No. 32
Route to Pond 8
Hyd. No. 32 -- 2 Year
Q (cfs)
14.00
12.00
10.00
4.00
f►a[iIi�
0.00
6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 31 011111 Total storage used = 8,500 cuft

I
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 32
Route to Pond 8
Hydrograph type
= Reservoir
Peak discharge
= 19.82 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 58,794 cuft
Inflow hyd. No.
= 31 - Post Area to Pond 8
Max. Elevation
= 360.82 ft
Reservoir name
= Pond 8
Max. Storage
= 12,550 cuft
Storage Indication method used.
Q (cfs)
24.00
20.00
16.00
12.00
m
4.00
0.00 '
0 2 4
Hyd No. 32
Route to Pond 8
Hyd. No. 32 -- 10 Year
Q (cfs)
24.00
20.00
16.00
12.00
4.00
i i i
0.00
6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 31 011111 Total storage used = 12,550 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4
Hyd. No. 32
Route to Pond 8
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 100 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 31 - Post Area to Pond 8
Max. Elevation
Reservoir name
= Pond 8
Max. Storage
Storage Indication method used.
Q (cfs)
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 32
Route to Pond 8
Hyd. No. 32 -- 100 Year
4
Monday, 05 / 4 / 2015
= 37.51 cfs
= 12.03 hrs
= 99,919 cuft
= 361.01 ft
= 13,450 cuft
6 8 10 12 14 16 18 20 22 24
Hyd No. 31 011111 Total storage used = 13,450 cuft
Q (cfs)
40.00
30.00
20.00
10.00
1 0.00
26
Time (hrs)

1
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 33
Pond 8 to AP #1
Hydrograph type
= Reach
Peak discharge
= 3.472 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.30 hrs
Time interval
= 2 min
Hyd. volume
= 24,653 cuft
Inflow hyd. No.
= 32 - Route to Pond 8
Section type
= Trapezoidal
Reach length
= 929.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.98 ft /s
Routing coeff.
= 0.4806
Modified Att -Kin routing method used.
Q (cfs)
4.00
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 33
Pond 8 to AP #1
Hyd. No. 33 -- 1 Year
6 8 10
Hyd No. 32
12 14 16
Q (cfs)
4.00
3.00
2.00
1.00
'_ ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 33
Pond 8 to AP #1
Hydrograph type
= Reach
Peak discharge
= 3.780 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.30 hrs
Time interval
= 2 min
Hyd. volume
= 32,276 cuft
Inflow hyd. No.
= 32 - Route to Pond 8
Section type
= Trapezoidal
Reach length
= 929.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 4.04 ft /s
Routing coeff.
= 0.4863
Modified Att -Kin routing method used.
Q (cfs)
4.00
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 33
Pond 8 to AP #1
Hyd. No. 33 -- 2 Year
6 8 10
Hyd No. 32
12 14 16
Q (cfs)
4.00
3.00
2.00
1.00
'_ ' 0.00
18 20 22 24 26
Time (hrs)

I
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 33
Pond 8 to AP #1
Hydrograph type
= Reach
Peak discharge
= 17.50 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 58,788 cuft
Inflow hyd. No.
= 32 - Route to Pond 8
Section type
= Trapezoidal
Reach length
= 929.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 5.51 ft /s
Routing coeff.
= 0.6090
Modified Att -Kin routing method used.
Q (cfs)
21.00
18.00
15.00
12.00
• m
MM
3.00
0.00 '
0 2 4
Hyd No. 33
Pond 8 to AP #1
Hyd. No. 33 -- 10 Year
Q (cfs)
21.00
18.00
15.00
12.00
• 11
. 11
3.00
0.00
6 8 10 12 14 16 18 20 22 24 26
Hyd No. 32 Time (hrs)

4
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. 00.4 Monday, 05 / 4 / 2015
Hyd. No. 33
Pond 8 to AP #1
Hydrograph type
= Reach
Peak discharge
= 36.19 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.07 hrs
Time interval
= 2 min
Hyd. volume
= 99,912 cuft
Inflow hyd. No.
= 32 - Route to Pond 8
Section type
= Trapezoidal
Reach length
= 929.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 6.21 ft /s
Routing coeff.
= 0.6607
Modified Att -Kin routing method used.
Q (cfs)
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 33
Pond 8 to AP #1
Hyd. No. 33 -- 100 Year
6 8 10
Hyd No. 32
12 14 16
Q (cfs)
40.00
30.00
20.00
10.00
0.00
18 20 22 24 26
Time (hrs)

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Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Monday, 05 / 4 / 2015
Pond No. 15 -
Pond 8
Stage
Storage
Elevation
Pond Data
Clv B Clv C
PrfRsr Wr A
Wr B Wr C
Wr D ExfiI User Total
ft
cuft
ft
cfs
Contours - User - defined contour areas.
Conic method used for volume calculation. Begining Elevation = 354.00 ft
cfs cfs
cfs cfs cfs cfs
Stage / Storage
Table
354.00
0.00
0.00 - --
- -- 0.00
0.00 - --
- -- - -- - -- 0.000
1.00
Stage (ft)
Elevation (ft)
1.26 is
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
- -- - -- - -- 1.245
2.00
0.00
354.00
2.00 is
113
- -- 0.00
0
0
3.00
1,553
1.00
355.00
2.57 is - --
332
0.00 - --
213
213
2,957
358.00
2.00
356.00
- -- 0.00
649
- -- - -- - -- 3.041
482
695
359.00
3.52 is
3.00
357.00
0.00 - --
1,086
6.00
858
1,553
3.90 is
3.82 is - --
4.00
358.00
- -- - -- - -- 3.822
1,749
13,414
1,404
2,957
2.30 is - --
- -- 28.45
5.00
359.00
8.00
2,926
362.00
2,312
5,269
- -- 39.45s
102.54 - --
6.00
360.00
4,068
3,481
8,750
7.00
361.00
5,287
4,664
13,414
8.00
362.00
6,582
5,922
19,336
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrfRsr]
[A] [B]
[C]
[D]
Rise (in)
= 24.00
8.00
0.00
0.00
Crest Len (ft)
= 18.85 40.00
0.00
0.00
Span (in)
= 24.00
8.00
0.00
0.00
Crest El. (ft)
= 360.41 360.82
0.00
0.00
No. Barrels
= 1
1
0
0
Weir Coeff.
= 3.33 2.00
3.33
3.33
Invert El. (ft)
= 354.00
354.00
0.00
0.00
Weir Type
= 1 Broad
- --
- --
Length (ft)
= 58.00
0.50
0.00
0.00
Multi -Stage
= Yes No
No
No
Slope ( %)
= 0.86
1.00
0.00
n/a
N -Value
= .013
.013
.013
n/a
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by Wet area)
Multi -Stage
= n/a
Yes
No
No
TW Elev. (ft)
= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B Clv C
PrfRsr Wr A
Wr B Wr C
Wr D ExfiI User Total
ft
cuft
ft
cfs
cfs cfs
cfs cfs
cfs cfs
cfs cfs cfs cfs
0.00
0
354.00
0.00
0.00 - --
- -- 0.00
0.00 - --
- -- - -- - -- 0.000
1.00
213
355.00
1.26 is
1.25 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 1.245
2.00
695
356.00
2.00 is
2.00 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 2.002
3.00
1,553
357.00
2.59 is
2.57 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 2.570
4.00
2,957
358.00
3.04 is
3.04 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 3.041
5.00
5,269
359.00
3.52 is
3.45 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 3.451
6.00
8,750
360.00
3.90 is
3.82 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 3.822
7.00
13,414
361.00
30.74 is
2.30 is - --
- -- 28.45
6.11 - --
- -- - -- - -- 36.85
8.00
19,336
362.00
39.87 is
0.39 is - --
- -- 39.45s
102.54 - --
- -- - -- - -- 142.38

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 8
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 72 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 28.27 ft2
Volume of Riser = 197.92 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 12,350 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 24 700 Ibs.
Concrete Base Design:
Length = 8.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 8.0 ft
Height = 3.0 ft
Concrete Base Total Weight = 28,800 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

Ownership and Property Information
SCM Name
BMP #8 Level Spreader
Legal Names of Owners of Property
Owner One
Legal Name of Owner
RFII -FH Sierra, LLC
Legal Business Address of Owner
2840 Plaza Place — Suite 360
Name of Local Owner Contact
Andrew Lineberry
E -mail for Local Owner Contact
lineberry @foreverhomellc.com
Phone Number for Local Owner Contact
(919) 870 -9711
Ext.
Owner Two
Legal Name of Owner
Legal Business Address of Owner
Name of Local Owner Contact
E -mail for Local Owner Contact
Phone Number for Local Owner Contact
Ext.
PIN /s on which SCM is Located
0769 -01 -29 -3411
Parcel ID /s on which SCM is Located
193301
DB /s and PG /s for Property on which
SCM is Located
007543/000243
PB /s and PG /s for Property on which
SCM is Located
0000000 /0000000
Coordinates for the Top of the Riser
or Control Structure (North Carolina
State Plane Coordinates, NAD 83)
Easting: 2061750.35
Northing: 800715.08

TSS Removal:
❑ Required ® Not Required
Required
TSS Loading into SCM
TSS Loading out of
TSS Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
Click here
Data Not
Data Not
Data Not
Data Not
Data Not
Data Not
Click here
to enter
Readily
Readily
Readily
Readily
Readily
Readily
to enter
text.
Available at
Available at
Available at
Available at
Available at
Available at this
text.
this Time
this Time
this Time
this Time
this Time
Time
TN Removal:
® Required ❑ Not Required
Required
TN Loading into SCM
TN Loading out of
TN Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
Ib /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
30%
1.34
25.97
1.21
18.28
0.13
7.69
29.61%
TP Removal:
® Required ❑ Not Required
Required
TP Loading into SCM
TP Loading out of
TP Loading Removed
Provided
Removal
SCM
by SCM
Removal
Efficiency
Efficiency
N
N
mg /L
lb /yr
mg /L
Ib /yr
mg /L
Ib /yr
(EMC)
(EMC)
(EMC)
35%
0.42
7.95
0.17
2.58
0.25
5.37
67.55%
Bacteria Removal: ❑ Required ® Not Required

SCM Drainage Area Characteristics
ELEMENT
CD
As -Built
Drainage Areas (acres)
5.26
Click here to enter text.
Total Drainage Area to the SCM (acres)
5.26
Click here to enter text.
Post Transportation I - NCDOT Streets (acres)
0
Click here to enter text.
Post Transportation I - City Streets (acres)
0.73
Click here to enter text.
Post Transportation I - Other (acres)
0
Click here to enter text.
Post Non - Transportation I (acres)
1.60
Click here to enter text.
Post Managed Pervious - HSG B (acres)
1.76
Click here to enter text.
Post Managed Pervious - HSG C (acres)
0
Click here to enter text.
Post Managed Pervious - HSG D (acres)
1.75
Click here to enter text.
Post Wooded Pervious - HSG B (acres)
0
Click here to enter text.
Post Wooded Pervious - HSG C (acres)
0
Click here to enter text.
Post Wooded Pervious - HSG D (acres)
0
Click here to enter text.
Total Drainage Area Imperviousness to SCM ( %)
33.2%
Click here to enter text.
Post Unit Loading, w /out Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP
Post Unit Loading, w/ Treatment (lb /ac /yr)
N/A
of TN
N/A
of TP

SCM Vital Statistics
ELEMENT
CD
As -Built
Invert Elevation of Flow - Splitter Structure (ft
353.50)
Click here to enter text.
above MSL)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
Invert Elevation of the Connection to the Forebay
353.50
Click here to enter text.
(ft)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
Invert Elevation of the Bypass Weir (ft)
355.87
Click here to enter text.
Width of Blind Swale- Linear Wetland (ft)
8.5'
Click here to enter text.
Length of level Spreader Lip (ft)
30'
Click here to enter text.
Type of Vegetated Filter Strip (VFS): A: 50 -ft
B
Click here to enter text.
Riparian Area; B: 30 -ft Engineered Filter Strip
[EFS]; or C: 20 -ft EFS + 50 -ft Restored Riparian
Buffer
Slope of VFS in the Direction of Flow ( %)
5.00%
Click here to enter text.
Type of Bypass System: Natural Draw (ND),
Constructed Bypass
Click here to enter text.
Constructed Bypass Channel (CBC), or
Channel
Constructed Bypass Pipe (CBP)
Peak Flow Rate Directed to Level Spreader (cfs)
3.00 cfs
Click here to enter text.
Peak Flow Rate (10 -yr Storm) Directed to Bypass
16.85 cfs
Click here to enter text.
System (cfs)
Estimates, Sureties, Etc.
Engineer's Estimate (EE) of Probable Cost to Construct Facility ($)
TBD
Fund Payment Amount (As Applicable): 25% of EE ($)
TBD
[A] Annual O &M Costs ($)
TBD
[B] Annual Certification Costs ($)
TBD
[C] Annual O &M and Certification Costs: [A] + [B] ($)
TBD
[D] Annualized Major Repair and Replacement Costs: 1/3 [A] ($)
TBD
[E] Total Annualized Maintenance Costs: [C] + [D] ($)
TBD
[F] 20 x Total Annualized Maintenance Costs (As applicable): 20 x [E] ($)
TBD
Annual O &M and Certification Funds (Residential Only) to be Set Aside
by Agreement: [C] ($)
TBD

Annual Major Repair and Replacement Funds (Residential Only) to be Set
Aside by Agreement: [D] ($)

1109 -001 Laurel Grove
Pond 8 Bypass
Bypass Channel Dimensions:
I
height = 1.00 ft
3 :1 3 :1
width = 5 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.14
ft/ft
Channel Design Calculations:
Channel Area=
8.00
ft'
Wetted Perimeter (@ %a„ )=
11.32
ft
Vmm in Channel=
12.63
ft/sec (Assuming full -depth flow)
Q10 (post development):
16.85
cfs
Maximum Flow in Channel:
101.08
cfs
*
CHANNEL
IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
I
height =
0.376 ft
3 :1
3 :1
width =
5 ft
Flow Area=
2.30
ft2
Wetted Perimeter (@ Cho)=
7.37
ft
Quo Associated with Flow Depth:
16.85
cfs
V10 in Channel=
7.33
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.38 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.14 channel gradient in ft/ft
T < 3.3 = Class I Rip -Rap
T =
3.28 Ib /sgft
T < 8.0 = Class 11 Rip Rap

PHIEDENS
LAND CORP
ENGINEERING - DEVELOPMENT
Inlet / Outlet Calculations
Project: Laurel Grove
Pipe: Pond 8 Flow Splitter
Design By: Adam Lynch
Date: 5/4/15
Check Inlet Control
Hw;c = Hw /D x D, where: Hw /D = 0.64 (from Chart 2)
D= 18 in= 1.50 ft
Hw;c = .96 ft
Check Outlet Control
Hwoc = ho + H - Lso
ho = dc+ D where: dc = critical depth (from chart 16) = 0.7
2 D= 2 f
1.1
H = head loss in pipe = 1.0 + Ke + 29n2L x VG
81.33 2g
0.4 (from chart 9)
LSD = length of pipe x slope of pipe
= 1 ft x 1.00%
= 0.01
HwOC = 1.49 ft
Hwoc > Hwic - Outlet Control
Hw = 1.49 ft Bypass elevation from bottom of flowsplitter

�j
CHART
2
180
10.000
(2�
(3}
Ise
8,000
EXAMPLE
I56
6.000
fl•ty ;ncna (3.5 trs�}
g
5,000
0 -e20 e4
3.
144
5.
4,000
2!1 ' wyf
132
o ts.
S'
4.
3,000
((] x -5 as
4.
Iz0
(2) 2.1
2,000
105,
96
1,000
3.
54
600
500
72
400
!
3
2.
=
300*
i
1.5
1.5
x
cr
60
n
200
p..
(.5
?
z
/
w
X
0
54
0
48
by
100
>
Q
80
:z
a
U
a
60
-
W
1.0
I.0
42
v
0
50 iiYY -SCALE ENTRANCE
1.0
40
0 TYPE
cc
w
9
1.-
36
30
(1) saaars adze 17th
or
S
33
n
- Q
Q
20
IZ) Greess and Wish
30
healaall
r
8
13) Grosse sal
'S
�nlsc�ia0
27
10
-7
.7-
24
5
.7
6
To use scale (2) or (31 praj.ct
2 ]
5
hari=■e12117 to scale li],issa
4
"a■ slydght laelinsl 11as thrasOh
are 0 !tail$, M r$►srsa h
�6
s
3
iillllralae.
.6
,
IB
2
,S
.3
i.0
1z
HEADWATER DEPTH
'FOR
CONCRETE 'PIPE CULVERTS
lIEAQM'AFER
SCALES 2�3
REvISM MAY 1964 WITH
MLET
CONTROL
evwc•u
v► ►w«c "AD$ -A&K m"
WR -2 4. :-

u-
0
I
w L
Q s
Of
a I:
=F
to I
c
-2000
-1000
800
-600
-500
•400
-300
-ZOO
N
w
x
U
-100 z
10
a
60 cc
LO
50 F
LU
.40
a
0
-30
-20
.10
.8
-6
- 5 .
-4
CHART 3
-12
BUREAU OF PUBLIC ROADS JAN. 196.)
5 -32
-.4
-.6
-.6
-1.0
-2
-3
-4
-5
-s
-8
-10
-20
HEAD FOR
CONCRETE PIPE CULVERTS
FLOWING FULL
n = 0.012
I f H
H W
Slay. Sow
z
a=
z
-
SUBMERGED OUTLET CULVERT FLOWING FULL
J
-�
HW • H. ho-1,50
12O
For oullal clown nal submarj4c% [Ompu4 HW 5y
method■ daacn bad in Ina Eraipn procaEUra
- IOB
-96
A
µ•O9 i
84
72
/
66
O
Cry
r
w
60
�i a
w
ti
-54
/ O ". ��
z
L *110
48'
0.48
-
i
_ -
- -- *x.0.5
00
"0
42
w
�QO
x
6100
36
SOP•
- 3 3
500
C
k00
r
-30
500 �
-27
f •
. 0
o
-24
-21
-18
-15
-12
BUREAU OF PUBLIC ROADS JAN. 196.)
5 -32
-.4
-.6
-.6
-1.0
-2
-3
-4
-5
-s
-8
-10
-20
HEAD FOR
CONCRETE PIPE CULVERTS
FLOWING FULL
n = 0.012

2 --
I
2.
1.5`
0
CHART 16
de CANNOT EXCEED TOP OF PIPE
0 10 20 30 40 50 60 70 80 90 100
DISCHARGE-Q -CFS
6
5
H-
w
w
4
v
2
E-
a 3
w
a
U 2
8
7
H
w
b w
u..
v
.p
M
5 r
CL
w
Q
Q
0 100 200 300 400 500 600 700 BOO 900 1000 U
DISCHARGE -Q -CFS t
U U
12
8 --
I !
6 I I CANNOT EXCEED TOP OF PIPE
3`
1P
9' DIA.
40 1000 2000 3000 4000
DISCHARGE -0 -CFS
BUREAU OF PUBLIC ROADS „
JAN.1964 CRITICAL DEPTH
5 -30, CIRCULAR PIPE

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Developed Watershed: AP -9 to Pond 9
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
Product
of
CN x Area
N
N
M
�
N
L
'a.,
�
N
L
2)
LL
0.98
96.04
--
Impervious -Road
98
1.05
102.90
--
Impervious - Sidewalk
98
0.15
14.70
--
Impervious - Driveway
98
0.25
24.50
B
Open Space -Lawn -Good Condition
61
3.01
183.61
D
Open Space -Lawn -Good Condition
80
2.85
228.00
Use only one CN value source per line. Totals =
8.29
649.75
( 649.75 Use CN 0.01295 sq mi)
CN (weighted) = total product _ = 78
total area 8.29
--
Impervious -Roof
98
0.98
96.04
--
Impervious -Road
98
1.05
102.90
--
Impervious - Sidewalk
98
0.15
14.70
--
Impervious - Driveway
98
0.25
24.50
B
Open Space -Lawn -Good Condition
61
3.01
183.61
D
Open Space -Lawn -Good Condition
80
2.85
228.00
Use only one CN value source per line. Totals =
8.29
649.75

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 35
Post Area to Pond 9
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 8.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 9
Wednesday, 01 / 7 / 2015
11.53 cfs
12.03 hrs
33,160 cuft
78
Oft
15.00 min
Type II
484
Q (cfs) Hyd. No. 35 -- 1 Year Q (cfs)
12.00 12.00
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 35 Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 35
Post Area to Pond 9
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 8.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
18.00
15.00
12.00
3.00
0.00 '
0 2 4
Hyd No. 35
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 9
Hyd. No. 35 -- 2 Year
Wednesday, 01 / 7 / 2015
15.52 cfs
12.03 hrs
43,986 cuft
78
Oft
15.00 min
Type II
484
Q (cfs)
18.00
15.00
12.00
11111M
3.00
-L� ' ' ' ' 0.00
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. 35
Post Area to Pond 9
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 8.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
0.00 ' '
0 2 4
Hyd No. 35
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 9
Hyd. No. 35 -- 10 Year
Wednesday, 01 / 7 / 2015
29.31 cfs
12.03 hrs
82,158 cuft
78
Oft
15.00 min
Type II
484
Q (cfs)
30.00
25.00
20.00
15.00
10.00
5.00
"r-- ' ' ' 0.00
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. 35
Post Area to Pond 9
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 8.300 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 7.40 in
Storm duration
= 24 hrs
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 35
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 9
Hyd. No. 35 -- 100 Year
Wednesday, 01 / 7 / 2015
50.26 cfs
12.03 hrs
142,156 cuft
78
Oft
15.00 min
Type II
484
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
-r- ' ' ' ' - ' 0.00
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
Wednesday, 02 / 18 / 2015
Hyd. No. 36
Route to Pond 9
Hydrograph type
= Reservoir
Peak discharge
= 2.249 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.37 hrs
Time interval
= 2 min
Hyd. volume
= 35,071 cuft
Inflow hyd. No.
= 35 - Post Area to Pond 9
Max. Elevation
= 380.35 ft
Reservoir name
= Pond 9
Max. Storage
= 12,050 cuft
Storage Indication method used.
Route to Pond 9
Q (cfs) Hyd. No. 36 -- 1 Year Q (cfs)
14.00 14.00
12.00 12.00
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 36 Hyd No. 35 1111111 Total storage used = 12,050 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 36
Route to Pond 9
Hydrograph type
= Reservoir
Peak discharge
= 3.586 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.30 hrs
Time interval
= 2 min
Hyd. volume
= 46,522 cuft
Inflow hyd. No.
= 35 - Post Area to Pond 9
Max. Elevation
= 381.44 ft
Reservoir name
= Pond 9
Max. Storage
= 16,716 cuft
Storage Indication method used.
Route to Pond 9
Q (cfs) Hyd. No. 36 -- 2 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 36 Hyd No. 35 011111 Total storage used = 16,716 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 36
Route to Pond 9
Hydrograph type
= Reservoir
Peak discharge
= 19.78 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 86,896 cuft
Inflow hyd. No.
= 35 - Post Area to Pond 9
Max. Elevation
= 383.38 ft
Reservoir name
= Pond 9
Max. Storage
= 27,745 cuft
Storage Indication method used.
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00 '
0 2 4
Hyd No. 36
Route to Pond 9
Hyd. No. 36 -- 10 Year
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 35 011111 Total storage used = 27,745 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 36
Route to Pond 9
Hydrograph type
= Reservoir
Peak discharge
= 54.30 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.03 hrs
Time interval
= 2 min
Hyd. volume
= 150,355 cuft
Inflow hyd. No.
= 35 - Post Area to Pond 9
Max. Elevation
= 384.01 ft
Reservoir name
= Pond 9
Max. Storage
= 31,974 cuft
Storage Indication method used.
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00 ' '
0 2 4
Hyd No. 36
Route to Pond 9
Hyd. No. 36 -- 100 Year
6 8 10
Hyd No. 35
12
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
' ' 0.00
14 16 18 20 22 24 26
Time (hrs)
011111 Total storage used = 31,974 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 37
Pond 9 to AP #1
Hydrograph type
= Reach
Peak discharge
= 2.234 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.63 hrs
Time interval
= 2 min
Hyd. volume
= 35,053 cuft
Inflow hyd. No.
= 36 - Route to Pond 9
Section type
= Trapezoidal
Reach length
= 1956.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 3.66 ft /s
Routing coeff.
= 0.2430
Modified Att -Kin routing method used.
Q (cfs)
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 37
Pond 9 to AP #1
Hyd. No. 37 -- 1 Year
6 8 10
Hyd No. 36
12 14 16
Q (cfs)
3.00
2.00
1.00
0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 37
Pond 9 to AP #1
Hydrograph type
= Reach
Peak discharge
= 3.391 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.47 hrs
Time interval
= 2 min
Hyd. volume
= 46,504 cuft
Inflow hyd. No.
= 36 - Route to Pond 9
Section type
= Trapezoidal
Reach length
= 1956.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 4.00 ft /s
Routing coeff.
= 0.2623
Modified Att -Kin routing method used.
Q (cfs)
4.00
3.00
2.00
1.00
0.00
0 2 4
Hyd No. 37
Pond 9 to AP #1
Hyd. No. 37 -- 2 Year
6 8 10
Hyd No. 36
12 14 16
Q (cfs)
4.00
3.00
2.00
1.00
0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 37
Pond 9 to AP #1
Hydrograph type = Reach Peak discharge
Storm frequency = 10 yrs Time to peak
Time interval = 2 min Hyd. volume
Inflow hyd. No. = 36 - Route to Pond 9 Section type
Reach length = 1956.0 ft Channel slope
Manning's n = 0.024 Bottom width
Side slope = 2.0:1 Max. depth
Rating curve x = 4.101 Rating curve m
Ave. velocity = 5.51 ft /s Routing coeff.
Wednesday, 02 / 18 / 2015
= 15.45 cfs
= 12.23 hrs
= 86,877 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.3442
Modified Att -Kin routing method used.
Q (cfs)
Pond 9 to AP #1
Hyd. No. 37 -- 10 Year
Q (cfs)
21.00
21.00
18.00
18.00
15.00
15.00
12.00
12.00
9.00
9.00
6.00
6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 37 Hyd No. 36

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 37
Pond 9 to AP #1
Hydrograph type
= Reach
Peak discharge
= 46.04 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 150,336 cuft
Inflow hyd. No.
= 36 - Route to Pond 9
Section type
= Trapezoidal
Reach length
= 1956.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 6.65 ft /s
Routing coeff.
= 0.4014
Modified Att -Kin routing method used.
Q (cfs)
60.00
50.00
F,�
30.00
20.00
10.00
0.00 ' '
0 2 4
Hyd No. 37
Pond 9 to AP #1
Hyd. No. 37 -- 100 Year
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
0.00
6 8 10 12 14 16 18 20 22 24 26
Hyd No. 36 Time (hrs)

v
0
U
C
M
i01
�QI
rte'
QI
Ql
ICI
LL.
T c-
O f3
-0 Lo iD
f2 CO q
U v L
fl N V) M dD C)
H W (1) ri aC C)
co o LV
o n- 00
m W
m f3 nI)
0o a) 0 C)
'S C) RS
U) U)
o ri Q>
O 1 Q)
p f2
�I 0 O
C O O Q- C)
_ ZJ
o� on ir.
(1) wI- o EM
U (h
0 m W
O [_
_j U frtij
O Q w
O O > 0O C
O 0
o U m E
O > co
co U L-
N
C
O
C)
cn
c.
N 1�;?
c)
C '
p U.)
LL 2'
rn
rb
N
(Y)
N >
U) N
It W
L Q
to N
t2
L�
cri
,� •in
is
s=
cn
CL
f)3
cq
C)
u�
0 0 C)
0 0 0 0 0 0 0
CN 0 0 o O o a)
OD cfl v 014 ° m CU
I I i I CO
OL

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Pond No. 17 - Pond 9
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 374.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00
374.00
363
0
0
1.00
375.00
724
533
533
2.00
376.00
1,159
933
1,466
3.00
377.00
1,668
1,406
2,872
4.00
378.00
2,252
1,953
4,824
5.00
379.00
2,911
2,574
7,398
6.00
380.00
3,647
3,272
10,670
7.00
381.00
4,253
3,946
14,616
8.00
382.00
5,329
4,780
19,396
9.00
383.00
6,277
5,796
25,192
10.00
384.00
7,296
6,779
31,972
11.00
385.00
8,389
7,835
39,807
Culvert / Orifice Structures
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Weir Structures
Storage / Discharge Table
[A]
[B]
[C]
[PrfRsr]
[A]
[B]
[C]
[D]
Rise (in)
= 18.00
6.00
10.00
0.00
Crest Len (ft)
= 12.54
30.00
0.00
0.00
Span (in)
= 18.00
6.00
10.00
0.00
Crest El. (ft)
= 382.89
383.39
0.00
0.00
No. Barrels
= 1
1
1
0
Weir Coeff.
= 3.33
2.00
3.33
3.33
Invert El. (ft)
= 374.00
374.00
380.82
0.00
Weir Type
= 1
Broad
- --
- --
Length (ft)
= 120.00
0.50
0.50
0.00
Multi -Stage
= Yes
No
No
No
Slope ( %)
= 10.00
1.00
1.00
n/a
1,466
376.00
1.17 is
1.17 is
0.00
N -Value
= .013
.013
.013
n/a
- --
- --
1.166
3.00
2,872
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by
Wet area)
- --
- --
Multi -Stage
= n/a
Yes
Yes
No
TW Elev. (ft)
= 0.00
0.00
- --
0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B
Wr C
Wr D
ExfiI
User
Total
ft
cuft
ft
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
0.00
0
374.00
0.00
0.00
0.00
- --
0.00
0.00
- --
- --
- --
- --
0.000
1.00
533
375.00
0.76 is
0.75 is
0.00
- --
0.00
0.00
- --
- --
- --
- --
0.745
2.00
1,466
376.00
1.17 is
1.17 is
0.00
- --
0.00
0.00
- --
- --
- --
- --
1.166
3.00
2,872
377.00
1.48 is
1.48 is
0.00
- --
0.00
0.00
- --
- --
- --
- --
1.482
4.00
4,824
378.00
1.77 is
1.74 is
0.00
- --
0.00
0.00
- --
- --
- --
- --
1.744
5.00
7,398
379.00
1.97 is
1.97 is
0.00
- --
0.00
0.00
- --
- --
- --
- --
1.974
6.00
10,670
380.00
2.18 is
2.18 is
0.00
- --
0.00
0.00
- --
- --
- --
- --
2.181
7.00
14,616
381.00
2.51 is
2.37 is
0.13 is
- --
0.00
0.00
- --
- --
- --
- --
2.495
8.00
19,396
382.00
4.80 is
2.49 is
2.29 is
- --
0.00
0.00
- --
- --
- --
- --
4.783
9.00
25,192
383.00
7.59 is
2.58 is
3.49 is
- --
1.52
0.00
- --
- --
- --
- --
7.591
10.00
31,972
384.00
25.70 is
0.34 is
0.93 is
- --
24.43s
28.58
- --
- --
- --
- --
54.28
11.00
39,807
385.00
27.21 is
0.15 is
0.41 is
- --
26.65s
122.57
- --
- --
- --
- --
149.77

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 9
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 48 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = 10 ft
Cross - Sectional Area = 12.57 ft2
Volume of Riser = 125.66 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 7,841 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 15 683 Ibs.
Concrete Base Design:
Length = 6.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 6.0 ft
Height = 3.0 ft
Concrete Base Total Weight = 16,200 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

1109 -001 Laurel Grove
Pond 9
Existinq Channel Dimensions:
I
height = 1.00 ft
6 :1 9 :1
width = 0 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.13
ft/ft
Channel Design Calculations:
Channel Area=
7.50
ft'
Wetted Perimeter (@ 0,„a )=
15.14
ft
Vmm in Channel=
9.61
ft/sec (Assuming full -depth flow)
Q10 (post development):
19.78
cfs
Maximum Flow in Channel:
72.08
cfs
*
CHANNEL
IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
I
height =
0.616 ft
6 :1
9 :1
width =
0 ft
Flow Area=
2.84
ft2
Wetted Perimeter (@ Cho)=
9.32
ft
Quo Associated with Flow Depth:
19.78
cfs
V10 in Channel=
6.96
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.62 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.13 channel gradient in ft/ft
T < 4.0 = Class I Rip -Rap
T =
5.00 Ib /sgft
T < 8.0 = Class 11 Rip Rap

Worksheet 2: Runoff curve number and runoff
Project: Laurel Grove By: AFL Date: 12/17/14
Location: Checked: Date:
Circle one: Present Developed Watershed: AP -10 to Pond 10
1.) Runoff curve number (CN)
Soil Name
and
Hydrologic
Group
(appendix A)
Cover Description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected /connected impervious
area ratio)
CN Value'
Area
Acres
Sq. Ft.
Product
of
CN x Area
N
N
M
�
N
L
'a.,
�
N
L
2)
LL
1.16
113.68
--
Impervious -Road
98
0.91
89.18
--
Impervious - Sidewalk
98
0.20
19.60
--
Impervious - Driveway
98
0.27
26.46
B
Open Space -Lawn -Good Condition
61
2.15
131.15
D
Open Space -Lawn -Good Condition
80
3.09
247.20
Use only one CN value source per line. Totals =
7.78
627.27
( 0.01216 sq mi)
CN (weighted) = total product 81
total area 7.78 627.27 Use CN = =
--
Impervious -Roof
98
1.16
113.68
--
Impervious -Road
98
0.91
89.18
--
Impervious - Sidewalk
98
0.20
19.60
--
Impervious - Driveway
98
0.27
26.46
B
Open Space -Lawn -Good Condition
61
2.15
131.15
D
Open Space -Lawn -Good Condition
80
3.09
247.20
Use only one CN value source per line. Totals =
7.78
627.27

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 39
Post Area to Pond 10
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 7.780 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.00 in
Storm duration
= 24 hrs
Q (cfs)
14.00
12.00
10.00
. M
4.00
2.00
0.00 '
0 2 4
Hyd No. 39
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 10
Hyd. No. 39 -- 1 Year
Wednesday, 01 / 7 / 2015
12.79 cfs
12.03 hrs
36,167 cuft
81
Oft
15.00 min
Type II
484
Q (cfs)
14.00
12.00
10.00
11111M
4.00
f►a[iIi�
1� ' ' ' ' ' 0.00
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. 39
Post Area to Pond 10
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 7.780 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.50 in
Storm duration
= 24 hrs
Q (cfs)
18.00
15.00
12.00
3.00
0.00 '
0 2 4
Hyd No. 39
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 10
Hyd. No. 39 -- 2 Year
Wednesday, 01 / 7 / 2015
16.75 cfs
12.03 hrs
47,046 cuft
81
Oft
15.00 min
Type II
484
Q (cfs)
18.00
15.00
12.00
11111M
3.00
.0� ' ' ' ' 0.00
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. 39
Post Area to Pond 10
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 7.780 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 5.10 in
Storm duration
= 24 hrs
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00 '
0 2 4
Hyd No. 39
6 8
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Area to Pond 10
Hyd. No. 39 -- 10 Year
Wednesday, 01 / 7 / 2015
30.11 cfs
12.03 hrs
84,640 cuft
81
Oft
15.00 min
Type II
484
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
'r ' ' ' 0.00
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. 39
Post Area to Pond 10
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 100 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 7.780 ac
Curve number
Basin Slope
= 0.0%
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 7.40 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 39
Post Area to Pond 10
Hyd. No. 39 -- 100 Year
6 8 10 12 14 16
Wednesday, 01 / 7 / 2015
= 49.97 cfs
= 12.03 hrs
= 142,587 cuft
= 81
= Oft
= 15.00 min
= Type II
= 484
Q (cfs)
50.00
40.00
30.00
20.00
10.00
- ' 0.00
18 20 22 24 26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 40
Route to Pond 10
Hydrograph type
= Reservoir
Peak discharge
= 1.396 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.70 hrs
Time interval
= 2 min
Hyd. volume
= 36,148 cuft
Inflow hyd. No.
= 39 - Post Area to Pond 10
Max. Elevation
= 385.71 ft
Reservoir name
= Pond 10
Max. Storage
= 16,320 cuft
Storage Indication method used.
Q (cfs)
14.00
12.00
10.00
. IM
4.00
2.00
Route to Pond 10
Hyd. No. 40 -- 1 Year
0.00 '
0 4 8 12
Hyd No. 40 Hyd No. 39
16 20 24 28
011111 Total storage used = 16,320 cuft
Q (cfs)
14.00
12.00
10.00
4.00
f►a[iIi�
0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 40
Route to Pond 10
Hydrograph type
= Reservoir
Peak discharge
= 1.599 cfs
Storm frequency
= 2 yrs
Time to peak
= 12.80 hrs
Time interval
= 2 min
Hyd. volume
= 47,027 cuft
Inflow hyd. No.
= 39 - Post Area to Pond 10
Max. Elevation
= 386.43 ft
Reservoir name
= Pond 10
Max. Storage
= 22,318 cuft
Storage Indication method used
Q (cfs)
18.00
15.00
12.00
3.00
0.00
0 4
Hyd No. 40
Route to Pond 10
Hyd. No. 40 -- 2 Year
8 12
Hyd No. 39
16 20 24 28
011111 Total storage used = 22,318 cuft
Q (cfs)
18.00
15.00
12.00
3.00
1 0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 40
Route to Pond 10
Hydrograph type
= Reservoir
Peak discharge
= 2.363 cfs
Storm frequency
= 10 yrs
Time to peak
= 12.97 hrs
Time interval
= 2 min
Hyd. volume
= 84,621 cuft
Inflow hyd. No.
= 39 - Post Area to Pond 10
Max. Elevation
= 388.51 ft
Reservoir name
= Pond 10
Max. Storage
= 43,970 cuft
Storage Indication method used.
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
Route to Pond 10
Hyd. No. 40 -- 10 Year
0.00 ' '
0 4 8 12
Hyd No. 40 Hyd No. 39
16 20 24 28
011111 Total storage used = 43,970 cuft
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
5.00
1 0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Wednesday, 02 / 18 / 2015
Hyd. No. 40
Route to Pond 10
Hydrograph type
= Reservoir
Peak discharge
= 40.54 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.13 hrs
Time interval
= 2 min
Hyd. volume
= 142,568 cuft
Inflow hyd. No.
= 39 - Post Area to Pond 10
Max. Elevation
= 389.01 ft
Reservoir name
= Pond 10
Max. Storage
= 49,822 cuft
Storage Indication method used.
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 2 4
Hyd No. 40
Route to Pond 10
Hyd. No. 40 -- 100 Year
6 8 10 12
Hyd No. 39
14 16 18 20 22 24 26
011111 Total storage used = 49,822 cuft
Q (cfs)
50.00
40.00
30.00
20.00
10.00
--4 0.00
28
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 41
Pond 10 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 40 - Route to Pond 10
Section type
Reach length
= 3720.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.35 ft /s
Routing coeff.
Modified Att -Kin routing method used.
Pond 10 to AP #1
Q (cfs) Hyd. No. 41 -- 1 Year
2.00
1.00
W 1 11 �
Wednesday, 02 / 18 / 2015
= 1.377 cfs
= 13.27 hrs
= 35,978 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1247
4 8 12 16 20 24 28
Hyd No. 41 Hyd No. 40
Q (cfs)
2.00
1.00
--1-1 0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 41
Pond 10 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 40 - Route to Pond 10
Section type
Reach length
= 3720.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.44 ft /s
Routing coeff.
Modified Att -Kin routing method used.
Pond 10 to AP #1
Q (cfs) Hyd. No. 41 -- 2 Year
2.00
1.00
W 1 11 �
Wednesday, 02 / 18 / 2015
= 1.586 cfs
= 13.30 hrs
= 46,857 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1277
4 8 12 16 20 24 28
Hyd No. 41 Hyd No. 40
Q (cfs)
2.00
1.00
---1 0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Hyd. No. 41
Pond 10 to AP #1
Hydrograph type
= Reach
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 40 - Route to Pond 10
Section type
Reach length
= 3720.0 ft
Channel slope
Manning's n
= 0.024
Bottom width
Side slope
= 2.0:1
Max. depth
Rating curve x
= 4.101
Rating curve m
Ave. velocity
= 3.70 ft /s
Routing coeff.
Modified Att -Kin routing method used.
Q (cfs)
3.00
2.00
1.00
W 1 11 �
4
Hyd No. 41
Pond 10 to AP #1
Hyd. No. 41 -- 10 Year
8 12
Hyd No. 40
Wednesday, 02 / 18 / 2015
= 2.247 cfs
= 13.13 hrs
= 84,451 cuft
= Trapezoidal
= 1.1 %
= 2.0 ft
= 4.0 ft
= 1.230
= 0.1368
16 20 244 28
Q (cfs)
3.00
2.00
1.00
--- 1 0.00
32
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Hyd. No. 41
Pond 10 to AP #1
Hydrograph type
= Reach
Peak discharge
= 25.07 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.27 hrs
Time interval
= 2 min
Hyd. volume
= 142,398 cuft
Inflow hyd. No.
= 40 - Route to Pond 10
Section type
= Trapezoidal
Reach length
= 3720.0 ft
Channel slope
= 1.1 %
Manning's n
= 0.024
Bottom width
= 2.0 ft
Side slope
= 2.0:1
Max. depth
= 4.0 ft
Rating curve x
= 4.101
Rating curve m
= 1.230
Ave. velocity
= 6.30 ft /s
Routing coeff.
= 0.2222
Modified Att -Kin routing method used
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0.00
0 4
Hyd No. 41
Pond 10 to AP #1
Hyd. No. 41 -- 100 Year
8 12
Hyd No. 40
16 20 24 28
Q (cfs)
50.00
40.00
30.00
20.00
10.00
—� 0.00
32
Time (hrs)

v
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U
C
CD
r
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r
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Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4
Wednesday, 02 / 18 / 2015
Pond No. 19 -
Pond 10
Storage / Discharge Table
Stage
Pond Data
Elevation
Clv A
Clv B Clv C
PrfRsr Wr A
Wr B Wr C
Wr D ExfiI User Total
ft
Contours - User - defined contour areas.
Conic method used for volume calculation. Begining Elevation = 383.00 ft
cfs
Stage / Storage
Table
cfs cfs
cfs cfs cfs cfs
0.00
0
383.00
0.00
Stage (ft)
Elevation (ft)
0.00 - --
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
384.00
0.00
383.00
- -- 0.00
4,271
- -- - -- - -- 0.745
0
0
385.00
1.00
384.00
- -- 0.00
5,495
- -- - -- - -- 1.166
4,870
4,870
386.00
2.00
385.00
- -- 0.00
6,802
- -- - -- - -- 1.482
6,136
11,006
387.00
3.00
386.00
- -- 0.00
8,188
- -- - -- - -- 1.744
7,484
18,490
388.00
4.00
387.00
- -- 0.00
9,654
- -- - -- - -- 1.974
8,910
27,400
389.00
5.00
388.00
- -- 14.32
11,202
- -- - -- - -- 40.58
10,417
37,817
390.00
6.00
389.00
- -- 21.03s
12,837
- -- - -- - -- 162.33
12,009
49,826
7.00
390.00
14,073
13,449
63,275
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrfRsr]
[A] [B]
[C] [D]
Rise (in)
= 18.00
6.00
0.00
0.00
Crest Len (ft)
= 12.54 40.00
0.00 0.00
Span (in)
= 18.00
6.00
0.00
0.00
Crest El. (ft)
= 388.51 388.54
0.00 0.00
No. Barrels
= 1
1
0
0
Weir Coeff.
= 3.33 2.00
3.33 3.33
Invert El. (ft)
= 383.00
383.00
0.00
0.00
Weir Type
= 1 Broad
- -- - --
Length (ft)
= 93.00
0.50
0.00
0.00
Multi -Stage
= Yes No
No No
Slope ( %)
= 9.68
1.00
0.00
n/a
N -Value
= .013
.013
.013
n/a
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in /hr)
= 0.000 (by Wet area)
Multi -Stage
= n/a
Yes
No
No
TW Elev. (ft)
= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage /
Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B Clv C
PrfRsr Wr A
Wr B Wr C
Wr D ExfiI User Total
ft
cult
ft
cfs
cfs cfs
cfs cfs
cfs cfs
cfs cfs cfs cfs
0.00
0
383.00
0.00
0.00 - --
- -- 0.00
0.00 - --
- -- - -- - -- 0.000
1.00
4,870
384.00
0.76 is
0.75 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 0.745
2.00
11,006
385.00
1.17 is
1.17 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 1.166
3.00
18,490
386.00
1.48 is
1.48 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 1.482
4.00
27,400
387.00
1.77 is
1.74 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 1.744
5.00
37,817
388.00
1.97 is
1.97 is - --
- -- 0.00
0.00 - --
- -- - -- - -- 1.974
6.00
49,826
389.00
15.62 is
1.30 is - --
- -- 14.32
24.96 - --
- -- - -- - -- 40.58
7.00
63,275
390.00
21.21 is
0.18 is - --
- -- 21.03s
141.13 - --
- -- - -- - -- 162.33

Anti - Flotation Calculation Worksheet EDENS
Designed By: Adam Lynch Date: 2/18/2015 Project: Laurel Grove
Checked By: Date: Drainge Area ID: Pond 10
The purpose of this worksheet is to design a concrete base for the proposed riser structure that will outweigh the maximum weight of water that could
fill the riser.
Riser Characteristics:
Diameter = 48 in
or
Length — ft
Width = ft
Max. Height of Water in Riser = ft
Cross - Sectional Area = 12.57 ft2
Volume of Riser = 75.40 ft,
Compute maximum weight of water within the structure:
Specific weight of water, y = 62.4 Ib /ft3
Total weight = 4,705 Ibs
Apply a Factor of Safety equal to 2 in order to design a proposed concrete base that will
exceed a minimum weight equal to 9 410 Ibs.
Concrete Base Design:
Length = 6.0 ft Assume specific weight of reinforced concrete = Ib /ft3
Width = 6.0 ft
Height = 2.0 ft
Concrete Base Total Weight = 10,800 Ibs Concrete base design outweighs max weight of water in riser.

EUR City of Durham
Public Works Department
Stormwater Services Divisions
1 8 6 9 101 City Hall Plaza, Durham, North Carolina, 27701
CTY OF MEDICINE Telephone [phone] FAX [phone]
Dry Detention Basin Design Summary
Stormwater Management Construction Plan Review:
A complete stormwater management construction plan submittal includes a design summary for each
stormwater BMP, design calculations, plans and specifications showing BMP, inlet and outlet structure details.
I. PROJECT INFORMATION
Project Name: Phase
PIN: Case #:
Design Contact Person: Phone #: �) -
Legal Name of Owner:
Owner Contact: Phone #: (� -
Owner Address:
Deed Book Page # or Plat Book Page# for BMP Property
For projects with multiple basins, specify which pond this worksheet applies to:
Detention provided for: 1 -year 2 -year 10 -year other
Dam Height: (feet) Dam Classification:
Elevations
Basin bottom elevation
ft.
(floor of the pond)
1 -year storm orifice /weir elevation
ft.
(invert elevation)
1 -year storm water surface elevation
ft.
2 -year storm orifice /weir elevation
ft.
(invert elevation)
2 -year storm water surface elevation
ft.
10 -year storm orifice /weir elevation
ft.
(invert elevation)
10 -year storm water surface elevation
ft.
Emergency spillway elevation
ft.
(invert of emergency spillway)
Top of embankment /dam
ft.
(elevation)
Maximum water surface elevation
ft.
(max. storm pond can safely pass)
Areas
Design storm surface area ft2 (Specify frequency event.•____year)
Drainage area ac. (total drainage to the pond)
Volumes
Total storage volume provided at design storm ft3
Total storage volume provided at top of dam ft3
Hydraulic Depth (volume of design storm divided by surface area of design storm)
Hydraulic Depth ft.
122

Discharges (Specify only applicable frequency events)
At BMP
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123
1 -year 2 -year 10 -year
-year
Inflow
cfs cfs
cfs
cfs
Routed outflow
cfs cfs
cfs
cfs
At Analysis Point(s) that BMP Contributes to
1 -year 2 -year 10 -year
-year
Pre - development
cfs cfs
cfs
cfs
Post - development w/o detention
cfs cfs
cfs
cfs
With detention
cfs cfs
cfs
cfs
Riser /Principal and Emerge
1 -year storm orifice /weir
2 -year storm orifice /weir
10 -year storm orifice /weir
- year storm orifice /weir
Principal spillway
Emergency spillway
icy Spillway Information
diameter in.
diameter in.
diameter in.
diameter in.
diameter in.
width ft.
IL REQUIRED ITEMS CHECKLIST
length
length
length
length
side slopes
:1 slope _%
The following checklist outlines design requirements. In the space provided to indicate the following design
requirements have been met and supporting documentation is attached.
Applicant's initials
a.Riprap outlet protection, if provided, reduces flow to non - erosive velocities (provide
calculations).
b. The basin side slopes are no steeper than 3:1.
c.Vegetative cover for the basin is specified. No woody vegetation is permitted on the
embankment.
d. A trash rack or similar device is provided for both the overflow and orifice. Flat top trash
racks are not acceptable. Access hatch has been provided.
e.A recorded drainage easement is provided for each basin including access to the nearest right -
of -way and is graded per Section 8.3, Stormwater Control Facilities (BMPs).
f. If the basin is used for sediment and erosion control during construction, a note requiring
clean out and vegetative cover being established prior to use as a dry detention basin shall be
provided on the construction plan.
g. Anti - floatation calculations are provided for riser structure.
h. A plan view of the pond with grading shown is provided.
i. A profile through the forebay, main pond and spillway is provided. Water surface elevations
are shown on the profile.
j. Riser structure details are provided.
k. Compaction specifications for the embankment are provided on the plan.
1. Dam designed to account for a 5.00% settlement factor.
123

m. The minimum top of dam width has been provided for the pond embankment top width per
Section 8.3, Stormwater Control Facilities (BMPs).
Note: Executed Stormwater Facility Operation and Maintenance Permit Agreement, payment of permit
fee per facility and payment of surety are required prior to construction drawing approval.
124

1109 -001 Laurel Grove
Pond 10
Existinq Channel Dimensions:
I
height = 4.00 ft
2 :1 2.5 :1
width = 0 ft
Channel Data:
drainage area=
FLOW
acres
rainfall intensity, 1=
FROM
in /hr 10 year
runoff coefficient, c=
POND
friction factor, n=
0.035
channel slope =
0.15
ft/ft
Channel Design Calculations:
Channel Area=
36.00
ftZ
Wetted Perimeter (@ 0,„a )=
19.71
ft
Vmm in Channel=
24.63
ft/sec (Assuming full -depth flow)
Q10 (post development):
2.36
cfs
Maximum Flow in Channel:
886.77
cfs
*
CHANNEL
IS ADEQUATE
Calculate V,,:
Depth of Flow Dimensions:
I
height =
0.433 ft
2 :1
2.5 :1
width =
0 ft
Flow Area=
0.42
ft2
Wetted Perimeter (@ Cho)=
2.13
ft
Quo Associated with Flow Depth:
2.36
cfs
V10 in Channel=
5.59
ft /sec
Check Shear Stress for Channel Liner : T =vds
T < 1.45 = straw w/ net
where y=
62.45 Ib /cuft
T < 1.55 = curled wood mat
d=
0.43 depth of flow (ft)
T < 2.0 = Synthetic mat
S=
0.15 channel gradient in ft/ft
T < 4.0 = Class I Rip -Rap
T =
4.06 Ib /sgft
T < 8.0 = Class 11 Rip Rap

APPENDIX II
WATER QUALITY CALCULATIONS

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NUTRIENT 2

Jordan /}alts _/ ale Storm�>>ater Nutrient �oacflccountin wool IN 121 ?.
LProceed to Watershed Characteristics , V Skip to BMP Characteristics Skip to Summary
General Model Instructions
— Details ofthe development should be entered in the first two tabs (Watershed Characteristics
and BMP Characteristics); results may be viewed on the third tab (Development Summary).
— The cells shaded grey are those that allow /require user input.
— Selecting the physiographic /geologic region and precipitation location most appropriate for
the development of interest is essential in producing accurate results. Maps have been
provided (see right) to assist in this selection, but soil maps should be consulted, or soil tests
performed, to verify the presence of Triassic or sandhill /coastal plain soils. A list of counties
located within, or partially within, each region has also been provided for convenience.
— Each tab has detailed instructions and guidelines for entering the necessary information (this
information is also included below).
— To remove an entry in a cell with a dropdown list, select the blank row from the dropdown
menu or select the cell and press the 'delete' button.
If. Specific Tab Guidelines
Watershed Characteristics
— For non - residential watersheds., indicate areas of each land use type in Column 1 for both
pre- and post - development conditions.
— For residential watersheds, complete the required information in Column 2 for both pre -
and post - development conditions.
— If a given land use is not present in the given watershed, leave the cell blank or enter a
zero.
— Ensure that land use areas entered for both pre- and post - development conditions match
the total development area entered in cell 021.
— Residential areas may be entered by average lot size (column, part A), or may be
separated into individual land uses (column 2, part B) -- do NOT list out individual land
uses within an area already described by lot size.
— Unless runoff flowing onto the development from offsite is routed separately around or
through the site, the offsite catchment area draining in must be included in the acreage
values of the appropriate land use(s) and treated.
BMP Characteristics
— This spreadsheet allows the development to be divided into as many as 6 smaller
catchments.
— BMPs 1, 2, and 3 for a given catchment are assumed to operate in series, with the
outflow from 1 serving as the inflow to 2, etc.
— Ifthe outflow from an entire catchment (including outflow from selected BMPs) drains to
another BMP, indicate this in the drop down menu below the BMP type and leave all cells
for individual land uses blank.
— Not all BMP or catchments must be utilized. Simply leave fields blank in the columns not
needed.
— Leave cells blank or insert zeroes if a land use is not present in the area draining to the
BMP.
— For water harvesting BMPs, be sure to enter the percent volume reduction that will be
achieved by your system. Volume detention (catch- and - release mechanisms) will not be
considered - only proven volume reductions are valid inputs.
— Volume reduction efficiencies for undersized BMPs are calculated based on a 1:1 ratio (a
BMP that is 60% smaller than the required design size the assigned removal efficiency is
60% ofthe standard efficiency value). Effluent concentrations remain the same as full-
sized BMPs.
— IMPORTANT: for the land area calculation checks to occur, you MUST press enter after
entering a value for area to be treated by a BMP (not just click on the next cell).
— See User's Manual for instructions on modeling oversized BMPs.
Ill. Model Methodology (more detailed information in Users Manual)
— Calculating Runoff Volumes — Simple Method (CWP, 2007)
— A fraction of impervious cover was assigned to each land use based on literature
review and field exploration.
— A runoff coefficient, Rv, is calculated for each land use using the designated
impervious cover fractions. The total volume of runoff is then calculated based
onthe land use area, Rv, and the precipitation depth ofthe water quality event.
— Calculating Pollutant Loadings — Simple Method (CWP, 2007)
— An event mean concentration of TN and TP is assigned for each land use type
based on an extensive literature review.
— The total load of a given pollutant for a defined drainage area is calculated
based on the average annual rainfall depth, the runoff coefficient Rv, and the
representative event mean concentration value.
— The fraction of rainfall events that produce runoff is assumed to be 1.0.
— 8MP Removal Calculations
— Each BMP is assigned a representative event mean concentration for the
treated outflow leaving the system, as well as percentages of inflow that leave
the system as infiltration, evapotranspiration, overflow and outflow.
— The total mass of pollutant leaving the BMP is calculated using the following
equation: Mass.„ � = (EMCo„uiv,,,, *Volumeo„uiv,„) + (EMC1,r1. *Volumes1..)
— The percent mass removal achieved by the BMP system is calculated using the
following equation:
%Removal = ((EMCiotio *Volumeinfi_)- Mass o,s�(EMCinfio,,,, *Volumeigli ) -100
Triassic Basin
Piedmont
Locations for which rainfall data is available. Choose the location that most closely represents the site's precipitation characteristics (not necessarily the location that is geographically the
closest) on the "Watershed Characteristics' page.
Table 1. List of counties located within, or partially within, each region.
PIEDMONT & MOUNTAIN
COASTAL PLAIN
CAMA Counties
TRIASSIC BASIN
SANDHILLS
Rockingham Lee
Bladen
Beaufort
Durham
Montgomery
Alamance Lincoln
Columbus
Bertie
Granville
Moore
Alexander Macon
Cumberland
Brunswick
Wake
Lee
Alleghany Madison
Duplin
Camden
Chatham
Harnett
Anson McDowell
Edgecombe
Carteret
Lee
Cumberland
Ashe Mecklenburg
Halifax
Chowan
Moore
Hoke
Avery Mitchell
Harnett
Craven
Montgomery
Robeson
Buncombe Montgomery
Hoke
Currituck
Richmond
Scotland
Burke Moore
Johnston
Dare
Anson
Richmond
Cabarrus Nash
Jones
Gates
Union
Caldwell Northampton
Martin
Hertford
Rockingham
Caswell Orange
Moore
Hyde
Stokes
Catawba Person
Nash
New Hanover
Davie
Chatham Polk
Northampton
Onslow
Cherokee Randolph
Pitt
Pamlico
Clay Richmond
Richmond
Pasquotank
Cleveland Rowan
Robeson
Fender
Davidson Rutherford
Sampson
Perquimans
Davie Stanley
Scotland
Tyrrell
Durham Stokes
Wake
Washington
Forsyth Surry
Wayne
Franklin Swain
Gaston Transylvania
Graham Union
Granville Vance
Guilford Wake
Halifax Warren
Harnett Watauga
Haywood Wilkes
Henderson Wilson
Iredell Yadkin
Jackson Yancey
Johnston

A I B C D I E I F I G 1HI 11 J I K I L I M I N 1 O 1 P I Q I R I 5 I T I U
1
2 Watershed Characteristics Ver2.0 Clear All Values Return to Instructions I Proceed to BMP Characteristics J Skip to Development Summary 1
J JJ
18
19
Instructions
1. Select your physiographic /geologic region. (see map on 'instructions' page)
2. Enter the area of the entire development in square feet (ft).
3. Select the location that is most representative of the site's precipitation characteristics. (see map on 'instructions' page)
4. For each applicable land use, enter the total area of that land use that lies within the development under pre - development conditions.
5. For each applicable land use, enter the total area of that land use that lies within the development under post - development conditions, before BMP implementation.
6. Ensure that the sum of pre- and post - development areas entered equal the orginal development area.
7. Continue to "BMP Characteristics" tab.
Additional Guidelines
For non - residential watersheds, indicate acreages of each land use type in Column 1 for both pre- and post - development conditions.
For residential watersheds, complete the required information in Column 2 for both pre- and post - development conditions.
If a given land use is not present in the given watershed, leave the cell blank or enter a zero.
Ensure that land use areas entered for both pre- and post - development conditions match the total development area entered in cell 021.
Residential areas may be entered by average lot size (column, part A), or may be separated into individual land uses (column 2, part B) -- do NOT list out individual land uses within an
area already described by lot size.
Unless runoff flowing onto the development from offsite is routed separately around or through the site, the offsite catchment area draining in must be included in the acreage
values of the appropriate land use(s) and treated.
Region:
Triassic Basin
Soil Hydrologic Group
D
Precipitation location:
Raleigh
COLUMN 1 -- NON- RESIDENTIAL LAND USES
8,005,856
Development Name:
Pre- P
Post -
Adam Lynch
TN EMC T
TP EMC P
Development D
Development
(mg /L) (
(mg /L) (
(ftZ) (
(ft)
o
COMMERCIAL
of 1
1.44 0
Parking I
1.08 0
Roof
_
1 ac lots
2
2.24 0
Open/Landscaped
o
INDUSTRIAL
of 1
1.44 0
0.39
Parking I
1.08 0
0.15
2
Roof
0.44
Open/Landscaped
TRANSPORTATION
High De
PART B
Roadway
Driveway
_Parking lot
Roof
0.52 797,817
0.39 193,470
0.39 34,419
0.15 6,000 950,944
1.16 207,523
0.44 146,850 4,415,696
0.59
0.25 _ 7,853,006 1,405,987
0.15
Low De
1.4
1.0
1.44
1.44
Rural
1.08
1.4
Sidewalk /Patio
Lawn
Managed pervious
Forest
_Natural wetland*
Riparian buffer*
Open water*
LAND TAKEN UP BY BMPs
2.24
3.06
Sidewalk
1.47
PERVIOUS
1.08
Manage
Unmanaged
Forest
JURISDICTIONAL
Natural
Riparian
Open w
LAND TAKEN
Density (interstate, main) 3.67 0.43
Density (secondary, feeder) 1.4 0.52
1.14 0.47
1.4 1.16
Managed pervious 3.06 0.59
(pasture) 3.61 1.56
1.47 0.25
LANDS*
wetland -- --
buffer -- water -- --
N UP BY BMPs 1.08 0.15
*Jurisdictional land uses are not included in nutrient /flow calculations.
Total Development Area (ft ):
8,005,856
Development Name:
Pre- P
Post -
Adam Lynch
TN EMC T
TP EMC P
Development D
Development
(mg /L) (
(mg /L) (
(ftZ) (
(ft)
o
of 1
1.44 0
0.16
1.08 0
0.15 _
_
1 ac lots
2
2.24 0
0.44
o
2 -ac lots
of 1
1.44 0
0.39
1.08 0
0.15
2
2.24 0
0.44
Custom Lot Size
PART B
Roadway
Driveway
_Parking lot
Roof
0.52 797,817
0.39 193,470
0.39 34,419
0.15 6,000 950,944
1.16 207,523
0.44 146,850 4,415,696
0.59
0.25 _ 7,853,006 1,405,987
0.15
1.4
1.0
1.44
1.44
1.08
1.4
Sidewalk /Patio
Lawn
Managed pervious
Forest
_Natural wetland*
Riparian buffer*
Open water*
LAND TAKEN UP BY BMPs
2.24
3.06
1.47
1.08
*Jurisdictional land uses are not included in nutrient /flow calculations.
Total Development Area (ft ):
8,005,856
Development Name:
Laurel Grove
Model Prepared By:
Adam Lynch
COLUMN 2 -- RESIDENTIAL LAND USES
Custom Pre- Post -
Lot Size Age TN EMC TP EMC Development Development
(ac) (yrs) (mg /L) (mg /L)� (ftZ) (ftZ)
PART A
%s -ac lots
-ac lots
-ac lots
1 ac lots
2 -ac lots
Multi- family
Townhomes
Custom Lot Size
PART B
Roadway
Driveway
_Parking lot
Roof
0.52 797,817
0.39 193,470
0.39 34,419
0.15 6,000 950,944
1.16 207,523
0.44 146,850 4,415,696
0.59
0.25 _ 7,853,006 1,405,987
0.15
1.4
1.0
1.44
1.44
1.08
1.4
Sidewalk /Patio
Lawn
Managed pervious
Forest
_Natural wetland*
Riparian buffer*
Open water*
LAND TAKEN UP BY BMPs
2.24
3.06
1.47
1.08
LAND USE AREA CHECK
Total Development Area Entered (ft): 8,005,856
Total Pre - Development Calculated Area (ft): 8,005,856
Total Post - Development Calculated Area (ft): 8,005,856

BMP Characteristics Ver2.0 Return m watershed Proceed to Development
Clear All Values Return to Instructions Characteristics Summary
Instructions
1. Select the type of BMP for each catchment.
2. Enter the area of each land use type In the contributing drainage area for each BMP.
3. Continue to "Development Summary" tab.
Additional Guidelines
- This spreadsheet allows the development to be divided Into as many as 6 smaller catchments.
- BMPs 1, 2, and 3 for a given catchment are assumed to operate in series, with the outflow from 1 serving as the inflow to 2, etc.
- If the outflow from an entire catchment (including outflow from selected BMPS) drains to another BMP, indicate this in the drop down menu below the BMP type and leave all cells for individual land uses blank.
- Not all BMP or catchments must be utilized. Simply leave fields blank in the columns not needed.
- Leave cells blank or insert zeroes if a land use is not present in the area draining to the BMP.
- For water harvesting BMPS, be sure to enter the percent volume reduction that will be achieved by your system. Volume detention (catch- and - release mechanisms) will not be considered -only proven volume reductions are valid inputs.
The BMP undersizing option should only be used for existing development or retrofit sites.
- Volume reduction efficiencies for undersized BMPS are calculated based on a 1:1 ratio (a BMP that is 60% smaller than the required design size is assigned a removal efficiency equal to 60% of the standard efficiency
value). Effluent concentrations remain the same as full -sized BMP,.
- IMPORTANT: for the land area calculation checks to occur, you MUST press enter after entering a value for area to be treated by a BMP (not just click on the next cell).
-See User's Manual for instructions on modeling oversized BMPS.
Type of BMP:
If BMP is undersized, indicate the BMP's size
relative to the design size required to
capture the designated water quality depth
(i.e. 0.75 = BMP is 75% of required design
size):
-FOr water harvesting BMP, enter percent
volume reduction in decimal form.
catchment 1:
Catchment 2:
Catchment 3:
Catchment 4:
Catchment 5:
Catchment 6:
lots (Built before 1995)
lots (New)
/. -ac lots (Built after 1995)
,::c lots (Built before 1995)
Townhomes(New)
Townhomes (Built after 1995)
Townhomes (Built before 1995)
Multi- family (New)
Multi- family (Built after 1995)
Multi- family (Built before 1995)
Custom Lo[ Size (New)
Custom Lot Size (Built after 1995)
. .. ... .. .. .... . .. ... . CATCHMENT1 ----------------------------- ..- .-------------- - - - - -- CATCHMENT2 -------------------- - ... -. -.- -- ....- .-- ---.- .- .- ... -. -.- CATCHMENT3 ----------------------------- CATCHMENT4 ---------------------
BMP #1 BMP #2 BMP #3 BMP #1 BMP #2 BMP #3 BMP #1 BMP #2 BMP#3 BMP #1 T BMP #2 _ BMP 93
Level Spreader, I I I 1
Fifer Strip I
BMP DETAILS
BMP
Volume Reduction ( %)
TN Effluent Concen.
(mg/L)
TP Effluent Concern.
(mg/L)
Bloretention with lWS
35%
0.95
0.12
Bioretemion without lWS
15%
1.00
0.12
Dry Detention Pond
0%
1.20
0.20
Grassed Swale
0%
1.21
0.26
Green Roof
50%
1.08
0.15
Level Spreader, Filter Strip
20%
1.20
0.15
permeable Pavement-
0%
1.44
0.39
Sand Filter
5%
0.92
0.14
Water Harvesting
s er defined
1.08
0.15
Wet Detention Pond
5%
1.01
0.11
Wetland
15%
1.08
0.12
........ ...... . .. ... CATCHMENT 5 ---------------------
BMP#1 BMP #2 BMP #3
m
Does BMP accept the outflow from another Catchment? If so, indicate which one(s). (Land use areas entered below are in addition to the watershed areas treated by contributing catchment(s).)
no no no no no no
no no no -- -- -- no no no
no no no no no -- -- --
no no no no n no no no no
no no no no no no no no
no no no no no no no no no
Area treated Area treated Area treated Area treated Area treated Area treated
Area Treated by BMP #2 that Is by BMP #3 that is Area Treated by BMP #2 that Is by BMP #3 that is Area Treated by BMP #2 that is by BMP #3 that Is An
by BMP not treated by BMP nottreated by BMPS by BMP not treated by BMP nor treated by BMP, by BMP not treated by BMP not treated by BMP,
(ft) #1 #1 or #2 (k') #1 #1 or #2 (ft') #1 #1 or #2
(ft) (k) (k') (k'I (ft) Ik'1
TOTAL AREA TREATED BY BMP (k"'=: I 2,058,290 0 0 0 0 0
2,059,290 D
BMP #1 BMP #2
red
Total La nd USe
0 I
0
0
BMP #1 BMP #2
red
Total La nd USe
Allowable Total Land
hat is
y BMPS
Area Treated By
Use Area to be
Treated Based on
1
All BMPS
(ft')
Post -Derv. Areas
0
0
IN)
_
0
0
0
0
0
0
0
0
0
0
0 _
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
381071)
797,817
90,891
193,470
34,419
290 460
950,944
93,868
207,523
1,199,589
4,415,696
0
0
1,405,987
0
0

3. Development Summary
Development: Laurel Grove
Prepared By: Adam Lynch
Date: May 7, 2015
WATERSHED SUMMARY Ver2.0
REGION:
Triassic Basin
TOTAL DEVELOPMENT AREA (ft -):
8,005,856
Percent Impervious ( %)
27%
27%
0%
Pre - Development Conditions
Post - Development Conditions
Post - Development w/ BMPs
Percent Impervious
0.1%
27.3%
27.3%
( %)
Total Nitrogen Loading (lb /ac/yr)
437%
380%
Annual Runoff Volume
61%
24%
(c.f.)
1,535,209
8,953,522
8,290,729
Total Nitrogen EMC
0.15
Level Spdr, Filter
BMP3
(mg /L)
1.48
1.36
1.31
Total Nitrogen Loading
0.15
Permeable
--
(lb /ac /yr)
0.77
4.14
3.70
1.44
0.39
Sand Filter
Total Phosphorus EMC
(mg /L)
015
0.40
0.31
0.15
Wet Detention Pond 5%
1.01
Total Phosphorus Loading
(lb /ac /yr)
0.13
1.23
0.88
Percent Difference Between:
*Negative percent difference values indicate a decrease in runoff volume, pollutant concentration or pollutant loading. Positive values indicate an increase.
BMP SUMMARY Ver2.0
BMP VOLUME REDUCTIONS /EFFLUENT CONCENTRATIONS
I Volume Reduction TN Effluent Concen. TP Effluent Concen.
Pre -Dev. &
Post -Dev. without BMPs
Pre- Development &
Post - Development with BMPs
Post -Dev without BMPs &
Post -Dev with BMPs
Percent Impervious ( %)
27%
27%
0%
Annual Runoff Volume (c.f.)
483%
440%
-7%
Total Nitrogen EMC (mg /L)
-8%
-11%
-4%
Total Nitrogen Loading (lb /ac/yr)
437%
380%
-11%
Total Phosphorus EMC (mg /L)
61%
24%
-23%
Total Phosphorus Loading (lb /ac /yr)
836%
569%
-29%
*Negative percent difference values indicate a decrease in runoff volume, pollutant concentration or pollutant loading. Positive values indicate an increase.
BMP SUMMARY Ver2.0
BMP VOLUME REDUCTIONS /EFFLUENT CONCENTRATIONS
I Volume Reduction TN Effluent Concen. TP Effluent Concen.
*iftreating commercial parking lot, TP effluent concentration = 0.16 mg /L
Return to Instructions 1
Return to Watershed Characteristics
lReturn to BMP Characteristics 1
IPrint Summary l
CATCHMENT 1
( %) (mg /L) (mg /L)
Bioretention with
IWS
35% 0.95 0.12
Bioretention
CATCHMENT 3
-
-
CATCHMENT 4
15%
1.00
012
without IWS
CATCHMENT IS
Dry Detention Pond
0%
1.20
0.20
Grassed Swale
0%
1.21
0.26
Green Roof
50%
1.08
0.15
Level Spdr, Filter
BMP3
BMP1
BMP2
Strip
20%
1.20
0.15
Permeable
--
-
-
Pavement*
0%
1.44
0.39
Sand Filter
5%
0.92
0.14
Water Harvesting user defined
1.08
0.15
Wet Detention Pond 5%
1.01
0.11
Wetland I 15%
1.08
0.12
*iftreating commercial parking lot, TP effluent concentration = 0.16 mg /L
Return to Instructions 1
Return to Watershed Characteristics
lReturn to BMP Characteristics 1
IPrint Summary l
CATCHMENT 1
--
-
CATCHMENT 2
-
--
CATCHMENT 3
-
-
CATCHMENT 4
-
CATCHMENTS
CATCHMENT IS
BMP1 BMP2
BMP3
BMP1
BMP2
BMP3
BMP1
BMP2
BMP3
BMP1.
BMP2
BMP3
BMP1
BMP2
BMP3
BMP1
BMP2
BMP3
-
-
--
--
--
-
-
--
Catchment Outflow 0.603
Total Phosphorus (lb /ac /yr)
--
Level Spreader,
Filter Strip
--
--
Percent Reduction in Phosphorus Load (%) 69%
Total Area Treated
47.25
--
--
-
-
Total Inflow Volume
(c.f.)
3,313,967
--
--
-
-
-
--
--
-
--
-
--
-
-
-
-
-
-
Percent Volume Reduced
20%
--
--
--
-
--
--
-
--
--
--
--
-
-
-
--
--
--
Inflow Nitrogen EMC
(mg/L)
1.36
--
--
--
-
Total Inflow Nitrogen
(lb /ac /yr)
5.96
--
--
-
-
Inflow Phosphorus EMC
(rng/L)
0.450
-
Total Inflow Phosphorus
(lb /ac /yr)
1.97
--
--
--
-
BMP Outflow
Nitrogen (Ibs /ac /yr)
-
-
-
-
-
BMP Outflow
Phosphorus (Ibs /ac /yr)
--
--
--
--
--
Catchment Outflow Nitrogen EMC (mg /L) 1.21
--
-
-
-
--
Catchment Outflow 4.23
-
-
-
-
Total Nitrogen (lb /ac /yr)
Percent Reduction in Nitrogen Load ( %)
29%
--
-
-
-
--
Catchment Outflow Phosphorus EMC
0.173
(mg /L)
--
--
-
-
--
--
--
-
-
--
Catchment Outflow 0.603
Total Phosphorus (lb /ac /yr)
--
--
-
--
--
Percent Reduction in Phosphorus Load (%) 69%

DURHAM
CITY OF DURHAM Neuse, Falls Lake and Jordan Lake Developer Nutrient Reporting Form
Please complete and submit the following information to the City of Durham Stormwater Services to
1869 characterize your project and assess the need to purchase nutrient offsets. See the
CM OF NT:DKWE City Stormwater Performance Standards. For nutrient offset information, see nutrient offset intro
PROJECT INFORMATION
Applicant Name:
RFII -FH SIERRA, LLC
Prepared by
Jarrod Edens, PE
Project Name (& Previous name, if applicable):
Laurel Grove - Phase 1
Site Plan #:
D1200218
Project Address (if available): Street: City /Town: County:
5713 Leesville Road Durham, NC Durham
Date: (mo/d/yr)
5/8/2015
Project
Locat'n:
ILat: (dec. degrees)
35d56'32.95 "N
Long: (dec. degree1193301.000000
7
PIN /PID #s:
Is this Redevelopment?
I ❑ Yes 0 No
Development Type (Please check all that apply)
Impervious Cover ( %) Pre - Construction:
0.10%
❑ Commercial ❑ Duplex Residential
❑ Industrial 0 Single - Family Residential
❑ Institutional ❑ Multi - Family Residential
Mixed Use
Impervious Cover ( %) Post - Construction:
27.30%
WATERSHED INFORMATION (See online map or alternative source for 12 -digit and 6 -digit IDs)
0 Upper Falls Basin, 12 -digit Watershed ID: 030202010502
❑ Lower Falls Basin, 12 -digit Watershed ID:
❑ Neuse /Outside of Falls Basin, 03020201 03020201
❑ Jordan Lake (Upper New Hope) 6 -digit Small
Watershed ID:
Jordan Lake Delivery
Factors ( %)
Nitrogen
Phosphorus
Site:
Bank:
Site:
Bank:
Name of Bank
Name of Bank
Neuse /Falls Lake Delivery Factors: There are no delivery factors, so the Delivery Factor = 1.
DURHAM STORMWATER PERFORMANCE STANDARDS FOR DEVELOPMENT COMPLIANCE ALTERNATIVE
Nutrient loading limits and on -site treatment minimum (Sections 70- 740(a) and Sections 70- 741(a))
Off -site treatment threshold ( %):
N:
1 40
P:
1 40
Required on -site reduction achieved?
N:
YES
P:
YES
NUTRIENT OFFSET REQUEST (Must meet the offsite thresholds — see above)
Nitrogen
Loading / Offset Needs (For the Jordan, Falls, and Neuse /Outside of Falls Watershed areas)
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(H)
(1) (Where
Applicable)
0)
Untreated
Loading
Rate
(Ibs /ac /yr)
Treated
Loading
Rate
(Ibs /ac /yr)
Load Rate
Target
(Ibs /ac /yr)
Reduction
Needed
(Ibs /ac /yr)
(from Compl.
worksheet)
Project Size
(square feet)
Offset
Duration
(yrs)
Site Delivery
Factor
State Buy Down
Amount Delivered
(Ibs)
D * E * F * G
Additional
5% if bank
not in City
limits (Ibs)
Total Delivered
(Ibs)
H + I
4.14
3.70
3.60
0.10
8,005,856
30
0.00
551.37
27.57
578.94
Phosphorus Loading / Offset Needs (For the Jordan and Falls Watershed areas)
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(H)
(1) (Where
Applicable)
0)
Untreated
Loading
Rate
(Ibs /ac /yr)
Treated
Loading
Rate
(Ibs /ac /yr)
Load Rate
Target
(Ibs /ac /yr)
Reduction
Needed
(Ibs /ac /yr)
(from Compl.
worksheet)
Project Size
(square feet)
Offset
Duration
(yrs)
Site Delivery
Factor
State Buy Down
Amount Delivered
(Ibs)
D * E * F * G
Additional
5% if bank
not in City
limits (Ibs)
Total Delivered
(Ibs)
H + I
1.23
0.88
n/a
0.00
8,005,856
30
0.00
0.00
0.00
0.00
Responsible Professional Engineer's Name:
Jarrod Edens, PE
PE #:
027352
Staff Name:
I
Staff e-mail:
I
Phone #:
Version 2 DRAFT, April 5,2013

APPENDIX III
RIP RAP INLET /OUTLET & PLUNGE POOL CALCULATIONS

L
1.5
1.4
1.3
1.2
W
0 1.0
m
LL
CL
ui
0.9
0
cr —
LL
0.8
U.
U.
>
0.7
>
LL 0.6
CL
0.5
LL
LL
CL -0.4
0.3
0.2
0.1
0
0 0.1 1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 l.'o
FIGURE VII -C-3 HYDRAULIC ELEMENTS DIAGRAM FOR CIPCULAR
CULVERTS FLOWING PART FULL
vii-C-11
I
FROUDE
p/FROUDEFULL
P/VFULL
—0 P/QEULL
A
P/AFULL
NOTE: VELOCITY.. DISCHARGE AND
FROUDE CURVES ARE BASED ON THE
MANNING EQUATION. IT IS ASSUMED
THAT MANNINGS "n" IS THE SAME FOR
PARTIAL FLCjW AS FOR FULL FLOW.
OP/QFULL
0
0 0.1 1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 l.'o
FIGURE VII -C-3 HYDRAULIC ELEMENTS DIAGRAM FOR CIPCULAR
CULVERTS FLOWING PART FULL
vii-C-11
I

1\
Table III -2.- Uniform flow in circular Sections flowing
/wr!!y, full From Reference 1113.
'D - discharge iniCUbie feet per ucond by Manning'i formula
d - depth of flow
D - diameter of pipe F n - Manning's coefficient
A - area of flow $ - slope of the channel bottom and of the water surface
R - hydraulic radius
/_ /�Y
A
R
do
Qn
d
�- )
(
A
R
Drs
On
-
D8/3S1/2
-
dS /3S 112
D 813 S 1/2
48/351/2
D2
O
O
D2
O
0.01
0.0013
0.0066
0.00007
1504
0.51
0.4027
0.2531
0.239
1.442
0.02
0.0037
0.0132
0.00031
10.57
0.52
0.417_7
0.2562
0.247
1.415
0.03
0.0069
0.0197
0.00074
8.56
05 3
O227�
A
0.2592
0.255
0.263
1.388
0.04
0.0105
0.0262
0.00133
7.33
0.54
0=427
0.2621
1.362
0.05
0.0147
0.0225
0.00222
6.55
0.55
04426
0.269
0.271
1.336
0.06
0,01, 92
0.0389
0.00328
555
0.56
04526
0.7676
0.279
1.311
0.07
0.0242
0.0451
0.00455
5.47
0.57
0.4625
0.2703
0.287
1.286
0.08
0.0294
0.0513
0.00604
5.09
0.58
0.4724
0.2728
0.295
1.262
0.09
0.0350
0.0575
0.00775
4.76
0.59
0.4622
0.2753
0.303
1.238
0.10
0.04„09
0.0635
0.0067
4.49
0.60
OA920
0.2776
0.311
1.215
0.11
0.0470
0.0695
0.01181
4.25
0.61
0,5018
0.2799
0.319
1.192
0.12
0.0534
0.0755
0.01417
4.04
0.62
_ 9,5115.-
0.2821
0.327
1.170
0.13
0.0600
0.0813
0.01674
3.86
0.63
0.52-12,,
0.2342
0.335
1.148
0.14
0.0668
0.0871
0.01952
3.69
0.64
65308
0.2862
0.343
1.126
0.15
0.0739
0.0929
0.0225
3.54
0.65
_q.5404-
0.2882
0.350
1.105
0.16
0.0311
0.0985
0.0257
3.41
0.66--
� _'0499
0.2900
0.358
1.084
0.17
0.0385
0.1042
0.0291
3.28
0.67
0
0.2917
0.356
1.064
0.18
0.0961
0.1097
0.0327
3.17
0.68
0:5687:
30.2933
0.373
1.044
0.19
0.1039
0.1152
0.0365
3.06
0.69
0.5 F$0
0.2948
0.380
1.024
0.20 •
0.1118
0.1206
0.0406
2.96
0.70
0.5872
0.2962
0.388
1.004
0.21
0.1199
0.1259
0.0448
2.87
-0.71
0.5964
0.2375
0.395
0985
0.22
0.1281
0.1312
0.0492
2.79
0.72.
0.6054
0.2987
0.402
0965
0.23
0.1365
0.1364
0.0537
2.71
0.73
0.6143
0.2998
0.409
0.947
0.24
0.1449
0.1416
0.0585
2.63
0.74
0.6231
0.3008
0.416
0.928
0.25
0.1535
0.1466
0.0634
2.56
0.75
0.6319
0.3017
0 422
0910
0.26
0.1623
0.1516
0.0686
2.49
0.76
0.6405
0.3024
0.429
0.891
0.27
0.1711
0.1 SG6
0.0739
2.42
0.77
0.6489
0.3031
0.435
0.873
0.28
-OA800-
0.1614
I 0.0793
2.36
0.78
0.6573
0.3036
0.441
0256
0.29
0.1890
0.16 62
0.0349
2.30
0.79
0.665 5
0.3039
0.447
0.838
0.30
0.1982
0.1709
0.0907
2.25
0.80
0.6736
0.3042
0.453
0.821
0.31
0.2074
0.1756
0.0966
2.20
0.81
0.661
0_:3043
0.458
0.804
0.32
0.2167
0.1802
0.1027
2.14
0.82
0.6893
0.3043
OA63
0:787
0.33
0.2260
0.1847
0.100=9
2.09
0.83
0.6969
0.3041
0.468
0.770
0.34'
0.2355
0.1891
0.1153
2.05
0.84
0.7043
03038
0.473
0.753
0.35
0.2450
0.1935
0.1218
2.00
0.85
0.7115
0.3033
0.477
0.736
0.36
0.2546
0.1978
0.1284
1.958
0.86
0.7186
0.3026
0.481
0.720
0.37
6.26,42
0.2020
0.1351
1.915
0.87
0.7254
0.3018
0.485
0.703
0.38
0.2739.
0.2062
0.1420
1.875
0.88
0.7320
0.3007
0.488
0.687
0.39
x.2836
0.2102
0.1490
1.835
0.89
0.7384
0.2995
0.491
0.670
0.40
0.2334
0.2142
0.1561
1.797
0.90
0.7445
0.2980
0.494
0.654
0.41.
.0.3032
0.2182
0.1633
1.760
0.91
0.7504
0.2963
0.496
0-637'
0.42
0.3130,
0.2220
0.1705
1.724
0.92
0.7S60
0.2944
0.497
0.621
0.43
0.3229
0.2258
0.1779
1.689
0.93
0.7612
0.2921
0.498
0.604
0.44
0.3328
0.2295
0.1854
1.655
0.94
0.7662
0.2895
0.498
0.588
0.45
03128
0.2331
0.1929
1.622
0.95
0.7707
0.2865
0.498
0.571
0.46
0.3527
0.2366
0.201
1.590
0.96
0.7749
0.2829
0.496
0.553
0.47
0.3627
0.2401
0.208
1.559
0.97
0.7785
0.2787
0.494
0.535
0.48
0.3727
0.2435
0.216
1.530
0.98
0.7817
0.2735
0.489
0.517:
0.49
0.3227
0.2468
0.22.1
1.500
0.99
0.7641
0.23,.+6
0.483
OA96
0.50
0.3927
0.2500
0.232
1.471
1.00
0.7854
02500
O.Lfi3
0.453
III -19

25
la
c
0
U
Q)
15
Q
10
0
101
••
.•
CLASS
OF
STONE
■'CC�CM
LENGTH
OF
APRON
MINIMUM
THICKNESS
OF STONI,
1
STONE
FINE
3"
4 X D
'C
2
MAC
r' LIGHT
C
.6 X -D
i2" '
3
STONE
- MEDIUM
13"
8 X D
18"
4
STONE
HEAVY
23"
8 X D
30"
�:
STONE
ECCEECCCECECCCE
23"
10 X D
30"
6
STONE
++
I HEAVY
■
12 X D
CCCCC
7
REQUIRES LARGER STONE OR ANOTHER TYPE OF DEVICE.
SUCH AS A STILLING BASIN. IMPACT STRUCTURE, ETC.
DESIGN IS BEYOND THE SCOPE OF THIS PROCEDURE.
S
7�P
...�9•
/ ■M
lI�+JC
V
V
:..
■nmom
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0 0
Figure 3: Zone Chart.
5 10 15 20 25
Diameter of Pipe in Feet
ZONE
APRON
MATERIAL
CLASS
OF
STONE
SIZE
OF
STONE
LENGTH
OF
APRON
MINIMUM
THICKNESS
OF STONI,
1
STONE
FINE
3"
4 X D
9"
2
STONE
r' LIGHT
�"
.6 X -D
i2" '
3
STONE
- MEDIUM
13"
8 X D
18"
4
STONE
HEAVY
23"
8 X D
30"
3
STONE
HEAVY
23"
10 X D
30"
6
STONE
++
I HEAVY
23"
12 X D
30"
7
REQUIRES LARGER STONE OR ANOTHER TYPE OF DEVICE.
SUCH AS A STILLING BASIN. IMPACT STRUCTURE, ETC.
DESIGN IS BEYOND THE SCOPE OF THIS PROCEDURE.
Figure 4: Apron Dimensions
IX -A8 -12

RIP RAP CALCULATION
Laurel Grove Pond 1
Intlet: Pond 1 - FES -101
Pipe Data (pipe size is assumed until final design performed)
D= 30 in
n = 0.013 Qmax = 129.99 cfs
slope = 0.1
Find Q,�
10 /Qmax 0.19
=
c = FROM
110 = POND Q10 = 24.82 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.19 1, y/D = 0.29
y/D < 0.5
From Table III -2, with y/D = 0.29
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 21.01 ft /sec
Rip Rap Dimensions: 30 ft
Long
33 ft
Wide
30 in
Deep
A/D2 = 0.1890
A= 1.18 sf
6 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 2
Intlet: Pond 2 - FES -201
Pipe Data (pipe size is assumed until final design performed)
D= 30 in
n = 0.013 Qmax = 129.99 cfs
slope = 0.1
� Q10/Qmax = 0.26
Find Qin
c = FROM
110 = POND Q10 = 34.32 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.26 1, y/D = 0.35
y/D < 0.5
From Table III -2, with y/D = 0.35
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 22.41 ft /sec
Rip Rap Dimensions: 30 ft
Long
33 ft
Wide
30 in
Deep
A/D2 = 0.2450
A = 1.53 sf
6 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 2
Intlet: Pond 2 - FES -252
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 87.81 cfs
slope = 0.15 :>
� Q10 /Qmax = 0.14
Find Qin
c = FROM
110 = POND Q10 = 12.23 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.14 1, y/D = 0.25
y/D < 0.5
From Table III -2, with y/D = 0.25
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 19.92 ft /sec
Rip Rap Dimensions: 24 ft
Long
26 ft
Wide
30 in
Deep
A/D2 = 0.1535
A = .61 sf
6 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 2
Intlet: Pond 2 - FES -279
Pipe Data (pipe size is assumed until final design performed)
D= 18 in
n = 0.013 Qmax = 29.44 cfs
slope = 0.0782 / \
" Q10/Qmax = 0.37
Find Qin
c = FROM
110 = POND Q10 = 10.78 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.37 1, y/D = 0.43
y/D < 0.5
From Table III -2, with y/D = 0.43
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 14.84 ft /sec
Rip Rap Dimensions: 12 ft
Long
14 ft
Wide
22 in
Deep
A/D2 = 0.3229
A = .73 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 3
Intlet: Pond 3 - FES -301
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 58.38 cfs
slope = 0.0663 / \
" Q10/Qmax = 0.25
Find Qin
c = FROM
110 = POND Q10 = 14.68 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.25 1, y/D = 0.34
y/D < 0.5
From Table III -2, with y/D = 0.34
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 15.58 ft /sec
Rip Rap Dimensions: 16 ft
Long
18 ft
Wide
22 in
Deep
A/D2 = 0.2355
A = .94 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 4
Intlet: Pond 4 - FES -409
Pipe Data (pipe size is assumed until final design performed)
D= 30 in
n = 0.013 Qmax = 51.34 cfs
slope = 0.0156 / \
" Q10/Qmax = 0.35
Find Qin
c = FROM
110 = POND Q10 = 17.98 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.35 1, y/D = 0.42
y/D < 0.5
From Table III -2, with y/D = 0.42
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 9.19 ft/sec
Rip Rap Dimensions: 15 ft
Long
18 ft
Wide
22 in
Deep
A/D2 = 0.3130
A = 1.96 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 4
Intlet: Pond 4 - FES -401
Pipe Data (pipe size is assumed until final design performed)
D= 15 in
n = 0.013 Qmax = 20.47 cfs
slope = 0.1
� Q10/Qmax = 0.10
Find Qin
c = FROM
110 = POND Q10 = 2.12 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.10 1, y/D = 0.22
y/D < 0.5
From Table III -2, with y/D = 0.22
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 10.59 ft /sec
Rip Rap Dimensions: 8 ft
Long
9 ft
Wide
22 in
Deep
A/D2 = 0.1281
A = .20 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 5
Intlet: Pond 5 - FES -501
Pipe Data (pipe size is assumed until final design performed)
D= 30 in
n = 0.013 Qmax = 77.99 cfs
slope = 0.036
� Q10/Qmax = 0.24
Find Qin
c = FROM
110 = POND Q10 = 18.77 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.24 1, y/D = 0.33
y/D < 0.5
From Table III -2, with y/D = 0.33
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 13.29 ft /sec
Rip Rap Dimensions: 20 ft
Long
23 ft
Wide
22 in
Deep
A/D2 = 0.2260
A = 1.41 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 6
Intlet: Pond 6 - FES -601
Pipe Data (pipe size is assumed until final design performed)
D= 36 in
n = 0.013 Qmax = 121.98 cfs
slope = 0.0333 / \
" Q10 /Qmax = 0.14
Find Qin
c = FROM
110 = POND Q10 = 17.39 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.14 1, y/D = 0.25
y/D < 0.5
From Table III -2, with y/D = 0.25
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 12.59 ft /sec
Rip Rap Dimensions: 24 ft
Long
27 ft
Wide
22 in
Deep
A/D2 = 0.1535
A = 1.38 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 7
Intlet: Pond 7 - FES -801
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 71.69 cfs
slope = 0.1
� Q10/Qmax = 0.16
Find Qin
c = FROM
110 = POND Q10 = 11.28 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.16 1, y/D = 0.27
y/D < 0.5
From Table III -2, with y/D = 0.27
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 16.48 ft /sec
Rip Rap Dimensions: 16 ft
Long
18 ft
Wide
22 in
Deep
A/D2 = 0.1711
A = .68 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 7
Intlet: Pond 7 - FES -1201
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 69.88 cfs
slope = 0.095
� Q10/Qmax = 0.16
Find Qin
c = FROM
110 = POND Q10 = 11.02 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.16 1, y/D = 0.27
y/D < 0.5
From Table III -2, with y/D = 0.27
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 16.10 ft /sec
Rip Rap Dimensions: 16 ft
Long
18 ft
Wide
22 in
Deep
A/D2 = 0.1711
A = .68 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 8
Intlet: Pond 8 - FES -901
Pipe Data (pipe size is assumed until final design performed)
D= 15 in
n = 0.013 Qmax = 20.47 cfs
slope = 0.1
� Q10/Qmax = 0.38
Find Qin
c = FROM
110 = POND Q10 = 7.88 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.38 1, y/D = 0.43
y/D < 0.5
From Table III -2, with y/D = 0.43
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 15.62 ft /sec
Rip Rap Dimensions: 10 ft
Long
11 ft
Wide
22 in
Deep
A/D2 = 0.3229
A = .50 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 9
Intlet: Pond 9 - FES -1001
Pipe Data (pipe size is assumed until final design performed)
D= 30 in
n = 0.013 Qmax = 93.20 cfs
slope = 0.0514 / \
" Q10/Qmax = 0.21
Find Qin
c = FROM
110 = POND Q10 = 19.19 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.21 1, y/D = 0.31
y/D < 0.5
From Table III -2, with y/D = 0.31
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 14.80 ft /sec
Rip Rap Dimensions: 20 ft
Long
23 ft
Wide
22 in
Deep
A/D2 = 0.2074
A = 1.30 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 10
Intlet: Pond 10 - FES -1101
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 67.71 cfs
slope = 0.0892 / \
" Q10/Qmax = 0.18
Find Qin
c = FROM
110 = POND Q10 = 12.20 cfs
A = CALC
From Figure VIII -C -3, with Q10/Qmax = 0.18 1, y/D = 0.28
y/D < 0.5
From Table III -2, with y/D = 0.28
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 16.94 ft /sec
Rip Rap Dimensions: 24 ft
Long
26 ft
Wide
30 in
Deep
A/D2 = 0.1800
A = .72 sf
6 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 1
Outlet: Pond 1
Pipe Data (pipe size is assumed until final design performed)
D= 18 in
n = 0.013 Qmax = 94.16 cfs
slope = 0.8
Find Q,�
10 /Qmax 0.02
-
c = FROM
110 = POND Q10 = 1.60 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.02 1, y/D = 0.11
y/D < 0.5
From Table III -2, with y/D = 0.11
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 15.13 ft /sec
Rip Rap Dimensions: 12 ft
Long
14 ft
Wide
22 in
Deep
A/D2 = 0.0470
A =.11sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 2
Outlet: Pond 2 Level Spreader Plunge Pool
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 18.97 cfs
slope = 0.007
Find Q,�
10 /Qmax 0.53
=
c = FROM
110 = POND Q10 = 10.00 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.53 1, y/D = 0.52
y/D > 0.5
From Table III -2, with y/D = 0.52
(Maximum Tailwater)
V10 - Q10 Zone:
A
= 6.06 ft/sec
Rip Rap Dimensions: 12 ft
Long
7 ft
Wide
22 in
Deep
A/D2 = 0.4127
A = 1.65 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 2
Outlet: Pond 2 Level Spreader Bypass
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 18.97 cfs
slope = 0.007
Find Q,�
10 /Qmax 0.73
=
c = FROM
110 = POND Q10 = 13.77 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.73 1, y/D = 0.63
y/D > 0.5
From Table III -2, with y/D = 0.63
(Maximum Tailwater)
V10 - Q10 Zone:
A
= 6.60 ft/sec
Rip Rap Dimensions: 12 ft
Long
7 ft
Wide
22 in
Deep
A/D2 = 0.5212
A = 2.08 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 3
Outlet: Pond 3
Pipe Data (pipe size is assumed until final design performed)
D= 18 in
n = 0.013 Qmax = 20.66 cfs
slope = 0.0385 / \
" Q10/Qmax = 0.33
Find Qin
c = FROM
110 = POND Q10 = 6.84 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.33 1, y/D = 0.39
y/D < 0.5
From Table III -2, with y/D = 0.39
(Minimum Tailwater)
V10 — Q10 Zone:
A
= 10.72 ft /sec
Rip Rap Dimensions: 9 ft
Long
11 ft
Wide
22 in
Deep
A/D2 = 0.2836
A = .64 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 4
Outlet: Pond 4
Pipe Data (pipe size is assumed until final design performed)
D= 18 in
n = 0.013 Qmax = 12.46 cfs
slope = 0.014
Find Q,�
10 /Qmax 0.44
=
c = FROM
110 = POND Q10 = 5.54 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.44 1, y/D = 0.46
y/D < 0.5
From Table III -2, with y/D = 0.46
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 6.98 ft/sec
Rip Rap Dimensions: 9 ft
Long
11 ft
Wide
22 in
Deep
A/D2 = 0.3527
A = .79 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 5
Outlet: Pond 5
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 23.67 cfs
slope = 0.0109
Find Q,�
10 /Qmax 0.61
=
c = FROM
110 = POND Q10 = 14.54 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.61 1, y/D = 0.55
y/D > 0.5
From Table III -2, with y/D = 0.55
(Maximum Tailwater)
V10 - Q10 Zone:
A
= 8.21 ft/sec
Rip Rap Dimensions: 12 ft
Long
7 ft
Wide
22 in
Deep
A/D2 = 0.4426
A = 1.77 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 6
Outlet: Pond 6 Level Spreader Plunge Pool
Pipe Data (pipe size is assumed until final design performed)
D= 30 in
n = 0.013 Qmax = 55.61 cfs
slope = 0.0183
Find Q,�
10 /Qmax 0.18
=
c = FROM
110 = POND Q10 = 10.00 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.18 1, y/D = 0.28
y/D < 0.5
From Table III -2, with y/D = 0.28
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 8.89 ft/sec
Rip Rap Dimensions: 15 ft
Long
18 ft
Wide
22 in
Deep
A/D2 = 0.1800
A= 1.13 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 6
Outlet: Pond 6 Level Spreader Bypass
Pipe Data (pipe size is assumed until final design performed)
D= 30 in
n = 0.013 Qmax = 55.61 cfs
slope = 0.0183
Find Q,�
10 /Qmax 0.39
=
c = FROM
110 = POND Q10 = 21.77 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.39 1, y/D = 0.44
y/D < 0.5
From Table III -2, with y/D = 0.44
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 10.47 ft /sec
Rip Rap Dimensions: 20 ft
Long
23 ft
Wide
22 in
Deep
A/D2 = 0.3328
A = 2.08 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 7
Outlet: Pond 7
Pipe Data (pipe size is assumed until final design performed)
D= 18 in
n = 0.013 Qmax = 16.00 cfs
slope = 0.0231
Find Q,�
10 max 0.29
=
c = FROM
110 = POND Q10 = 4.57 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.29 1, y/D = 0.36
y/D < 0.5
From Table III -2, with y/D = 0.36
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 7.98 ft/sec
Rip Rap Dimensions: 9 ft
Long
11 ft
Wide
22 in
Deep
A/D2 = 0.2546
A = .57 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 8
Outlet: Pond 8 Level Spreader Pluge Pool
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 21.02 cfs
slope = 0.0086
Find Q,�
10 /Qmax 0.48
=
c = FROM
110 = POND Q10 = 10.00 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.48 1, y/D = 0.47
y/D < 0.5
From Table III -2, with y/D = 0.47
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 6.89 ft/sec
Rip Rap Dimensions: 12 ft
Long
14 ft
Wide
22 in
Deep
A/D2 = 0.3627
A = 1.45 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 8
Outlet: Pond 8 Level Spreader Bypass
Pipe Data (pipe size is assumed until final design performed)
D= 24 in
n = 0.013 Qmax = 21.02 cfs
slope = 0.0086
Find Q,�
10 /Qmax 0.47
=
c = FROM
110 = POND Q10 = 9.85 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.47 1, y/D = 0.47
y/D < 0.5
From Table III -2, with y/D = 0.47
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 6.79 ft/sec
Rip Rap Dimensions: 12 ft
Long
14 ft
Wide
22 in
Deep
A/D2 = 0.3627
A = 1.45 sf
2 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 9
Outlet: Pond 9
Pipe Data (pipe size is assumed until final design performed)
D= 18 in
n = 0.013 Qmax = 33.29 cfs
slope = 0.1
Find Q,�
10 /Qmax 0.59
=
c = FROM
110 = POND Q10 = 19.78 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.59 1, y/D = 0.64
y/D > 0.5
From Table III -2, with y/D = 0.64
(Maximum Tailwater)
V10 - Q10 Zone:
A
= 16.56 ft /sec
Rip Rap Dimensions: 12 ft
Long
6 ft
Wide
22 in
Deep
A/D2 = 0.5308
A= 1.19 sf
3 (From Figure 3)

RIP RAP CALCULATION
Laurel Grove Pond 10
Outlet: Pond 10
Pipe Data (pipe size is assumed until final design performed)
D= 18 in
n = 0.013 Qmax = 32.75 cfs
slope = 0.0968
Find Q,�
10 /Qmax 0.07
-
c = FROM
110 = POND Q10 = 2.36 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.07 1, y/D = 0.18
y/D < 0.5
From Table III -2, with y/D = 0.18
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 10.91 ft /sec
Rip Rap Dimensions: 9 ft
Long
11 ft
Wide
22 in
Deep
A/D2 = 0.0961
A = .22 sf
2 (From Figure 3)

RIP RAP CALCULATION
FES 461 Outlet
Outlet: FES 461
Pipe Data (pipe size is assumed until final design performed)
D= 15 in
n = 0.013 Qmax = 25.12 cfs
slope = 0.1506
Find Q,�
10 /Qmax 0.07
-
c = FROM
110 = POND Q10 = 1.70 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.07 1, y/D = 0.18
y/D < 0.5
From Table III -2, with y/D = 0.18
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 11.32 ft /sec
Rip Rap Dimensions: 8 ft
Long
9 ft
Wide
22 in
Deep
A/D2 = 0.0961
A= .15sf
2 (From Figure 3)

RIP RAP CALCULATION
FES 1223 Outlet
Outlet: FES 1223
Pipe Data (pipe size is assumed until final design performed)
D= 15 in
n = 0.013 Qmax = 9.75 cfs
slope = 0.0227
Find Q,�
10 /Qmax 0.13
=
c = FROM
110 = POND Q10 = 1.31 cfs
A = CALC
From Figure VIII -C -3, with Q10 /Qmax = 0.13 1, y/D = 0.24
y/D < 0.5
From Table III -2, with y/D = 0.24
(Minimum Tailwater)
V10 - Q10 Zone:
A
= 5.79 ft/sec
Rip Rap Dimensions: 5 ft
Long
6 ft
Wide
22 in
Deep
A/D2 = 0.1449
A = .23 sf
1 (From Figure 3)