20191305 Ver 1_SW Management Report rev_20190927

STORMWATER MANAGEMENT REPORT
FOR
NEW RETAIL STORE
U.S. HIGHWAY 64 / CASHIERS ROAD & CHERRYWOOD DR.
HIGHLANDS, NC

09-26-2019

PREPARED FOR

CONTENTS
I. PREDEVELOPMENT CONDITIONS............................................................................... l
II. ANALYSIS METHODS.....................................................................................................1
III. RAINFALL INFORMATION.....--•.....................................................................................1
IV. EROSION CONTROL IMPEMENTATION SCHEDULE................................................2
V. POSTDEVELOPMENT CONDITIONS.............................................................................3
APPENDIX A. PRECONSTRUCTION SITE CALCULATIONS......................................4
DRAINAGEAREA MAP...............................................................................................................5
DRAINAGE ROUTING DIAGRAM..............................................................................................6
2, 5, 10, 25, 50, 100 -YEAR STORM EVENT CALCULATIONS ......................................... 7-30
APPENDIX B. POSTCONSTRUCTION SITE CALCI ?I.ATIONS..................................31
DRAINAGEAREA MAP............................................................................................................32
DRAINAGE ROUTING DIAGRAM............................................................................................33
2, 5, 10, 25, 50, 100 -YEAR STORM EVENT CALCULATIONS ..................................... 34-135
APPENDIX C. NRCS SOIL REPORT.................................................................... 136-140
PREPARED BY
Broadway Civil Designs of NC, LLC
216 Westside Square - Huntavlle, AL 35801
phone:[phone]• Fax: [2561533-7236
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I. PREDEVELOPMENT CONDITIONS
The site is a 2.24 acre piece of property located on the southwest side of U.S. Highway 64
(Cashiers Road) and Cherrywood Drive, in Macon County North Carolina. It is a previously
developed site with a gravel driveway. The remaining portions of the lot are covered with grass
and trees. There are two streams and two wetland areas present onsite. There is an unnamed
tributary to Big Creek that runs from south to north alongside Cherrywood Drive. There is
another unnamed tributary to Big Creek that runs from west to east neara the northern property
line that forms two wetland areas before it flows into the creek adjacent to Cherrywood Drive.
Existing onsite soils are classified as Cullasaja-Tuckasegee complex, Hydrologic Soil Group A,
and Udorthents, Hydrologic Soil Group C. The site generally slopes from south to north at about
4.7%. Surface runoff flows north to the wetland area before flowing into the unnamed tributary
to Big Creek.
II. ANALYSIS METHODS
In order to determine the pre- and post-development peak discharges and hydrographs of the
drainage basins, drainage area maps were developed based upon a topographic survey performed
by King Engineering of Concord, Inc., the USGS quad map of the area for the off-site drainage
areas, and the proposed site design. From these maps, the SCS curve numbers and times of
concentration were determined and input into HydroCAD 10.0, which calculated peak flows and
hydrographs for each runoff basin by the SCS TR-20 method. Reach and pond storages and
capacities were calculated by the storage-indication routing methods.
III. RAINFALL INFORMATION
Total rainfall depths for the studied storm events were obtained from NOAA Atlas 14 Volume 9
Version 2, Precipitation-Frequency Atlas of the United States, Southeastern States, available
from the Precipitation Frequency Data Server (http://hdsc.nws.noaa.gov/hdsc/pfds). The events
and corresponding 24-hour rainfall events are summarized below.
Event Rainfall Depth, inches
2 year 5.79
5 year 7.13
10 year 8.19
25 year 9.68
50 year 10.90
100 year 12.10

1

IV. EROSION CONTROL IMPLEMENTATION SCHEDULE
See the Initial, Intermediate, and Final Phase Erosion and Sedimentation Control plans accompanied this
document for locations of the practices described below.
INITIAL PHASE
1. Install construction exit pad (CEP) and type "A" silt fence (SB), double row where
indicated.
2. Clear trees as needed.
3. Strip and stockpile topsoil (TSG), and remove unsuitable material.
5. Temporary seeding to be installed on areas where grading and stabilization operations
have ceased and will not resume for 7 days.
INTERMEDIATE PHASE
1. Begin grading site in the building and parking areas.
2. Construction exit pad (CEP), double row of type "A" silt fence (SB), and temporary
seeding (TS) to remain and maintained as needed as grading progresses.
3. Install compost sock check dams (CS) in channels where indicated.
4. Install utilities (storm, sanitary, and water). Storm pipe outlet to be stabilized with outlet
protection (OP).
5. Protect grate inlets with block and gravel inlet protection (BIP) after installation.
6. Concrete washout (GK) to be established and maintained as necessary once concrete
pouring begins.
FINAL PHASE
1. Maintain construction exit pad (CEP), double row of type "A" silt fence (SB), check
dams (CS), and temporary seeding (TS) as site grading progresses.
2. Grade parking lot and construct building pad. Base, paving and building are to be
installed after utility construction is completed.
3. Install sod (SOD) on areas indicated as soon as practicable. Appropriate plant material
shall be installed area by area as site work permits.
4. Clean storm structures. Install any other permanent BMP.
5. Demuck all structural BMP's and safely dispose of material. Maintain silt fence until
vegetation has achieved 100% coverage across site with 85% density, then remove.

2

V. POSTDEVELOPMENT CONDITIONS
This project consists of constructing a 9100 sq.ft. retail store with a 28-space parking lot and
truck delivery area. The remaining areas will be landscaped with sod. Drainage from the roof
will be discharged on the surface and directed towards the curb line of the rear parking lot area.
All parking lot areas will be sloped to drain to one of six grate inlets located in the parking lot.
Those inlets will be connected to an 18” HDPE pipe network that will convey stormwater to an
underground detention chamber system located east of the building, near the driveway.
Proposed slopes of the parking lot range from 1.0% to 3.5%, while the remaining grassed areas
will be graded to a maximum slope of 4:1 H:V (25%).

A. WATER QUALITY AND QUANTITY CONTROL
In order to treat the first inch of stormwater runoff generated from this development, the
underground detention chamber system will include a separator row system which will remove
80% of the total suspended solids (TSS) from the stormwater. The separator row is wrapped in
filter fabric, and the system is designed so that stormwater entering the chambers must flow
through the separator row first, filtering 80% TSS before flowing downward and filling the
gravel bed and then the adjoining chambers.
To control the increased discharges due to this development, the on-site stormwater will be
detained in an underground detention chamber system. The chamber system will consist of 60
Cultec R-330XLHD chambers embedded in a gravel bed. The outflow will be controlled by the
use of a 6”x6” orifice and an 18”x12” weir in the outlet control box located near the northeast
end of the parking lot. The orifices will force storm water to back up and be stored in the
chambers. Discharge from the outlet control box will be directed to the northeast, where it will
be discharged on the surface, and flow to the wetland area adjacent to the unnamed tributary to
Big Creek.

SITE DISCHARGE COMPARISON
Event Predevelopment, cfs Postdevelopment, cfs Decrease, cfs
2 year 5.82 5.76 0.06
5 year 10.04 9.06 0.98
10 year 13.73 11.93 1.80
25 year 19.30 16.28 3.02
50 year 24.12 20.33 3.79
100 year 29.03 26.22 2.81

3

APPENDIX A
PRECONSTRUCTION SITE CALCULATIONS
4
Broadway Civil Designs of NC, PLLC
216 Westside Square • Huntsville, AL 35801
Phone: [phone] • Fax: [phone]
5
1EX
Site
2EX
Offsite PRE
Preconstruction Site
Discharge
Broadway Civil Designs of NC, PLLC
216 Westside Square • Huntsville, AL 35801
Phone: [phone] • Fax: [phone]
6

PRECONSTRUCTION SITE CALCULATIONS
2-YEAR STORM EVENT

7
Type III 24-hr 2-yr Rainfall=5.79"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 1HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 1EX: Site
Runoff = 5.45 cfs @ 12.03 hrs, Volume= 15,170 cf, Depth= 1.87"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
42,492 76 Woods/grass comb., Fair, HSG C
* 6,800 98 Ex. Road
48,244 43 Woods/grass comb., Fair, HSG A
97,536 61 Weighted Average
90,736 93.03% Pervious Area
6,800 6.97% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.5 296 0.0470 3.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 1EX: Site
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)6
5
4
3
2
1
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=97,536 sf
Runoff Volume=15,170 cf
Runoff Depth=1.87"
Flow Length=296'
Slope=0.0470 '/'
Tc=1.5 min
CN=61
5.45 cfs
8
Type III 24-hr 2-yr Rainfall=5.79"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 2HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2EX: Offsite
Runoff = 0.60 cfs @ 12.08 hrs, Volume= 3,568 cf, Depth= 0.60"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=71,247 sf
Runoff Volume=3,568 cf
Runoff Depth=0.60"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
0.60 cfs
9
Type III 24-hr 2-yr Rainfall=5.79"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 3HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Link PRE: Preconstruction Site Discharge
Inflow Area = 168,783 sf, 8.82% Impervious, Inflow Depth = 1.33" for 2-yr event
Inflow = 5.82 cfs @ 12.03 hrs, Volume= 18,738 cf
Primary = 5.82 cfs @ 12.03 hrs, Volume= 18,738 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link PRE: Preconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)6
5
4
3
2
1
0
Inflow Area=168,783 sf
5.82 cfs5.82 cfs
10

PRECONSTRUCTION SITE CALCULATIONS
5-YEAR STORM EVENT

11
Type III 24-hr 5-yr Rainfall=7.13"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 4HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 1EX: Site
Runoff = 8.43 cfs @ 12.03 hrs, Volume= 22,727 cf, Depth= 2.80"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
42,492 76 Woods/grass comb., Fair, HSG C
* 6,800 98 Ex. Road
48,244 43 Woods/grass comb., Fair, HSG A
97,536 61 Weighted Average
90,736 93.03% Pervious Area
6,800 6.97% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.5 296 0.0470 3.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 1EX: Site
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)9
8
7
6
5
4
3
2
1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=97,536 sf
Runoff Volume=22,727 cf
Runoff Depth=2.80"
Flow Length=296'
Slope=0.0470 '/'
Tc=1.5 min
CN=61
8.43 cfs
12
Type III 24-hr 5-yr Rainfall=7.13"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 5HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2EX: Offsite
Runoff = 1.75 cfs @ 12.05 hrs, Volume= 6,716 cf, Depth= 1.13"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=71,247 sf
Runoff Volume=6,716 cf
Runoff Depth=1.13"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
1.75 cfs
13
Type III 24-hr 5-yr Rainfall=7.13"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 6HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Link PRE: Preconstruction Site Discharge
Inflow Area = 168,783 sf, 8.82% Impervious, Inflow Depth = 2.09" for 5-yr event
Inflow = 10.04 cfs @ 12.03 hrs, Volume= 29,443 cf
Primary = 10.04 cfs @ 12.03 hrs, Volume= 29,443 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link PRE: Preconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=168,783 sf
10.04 cfs10.04 cfs
14

PRECONSTRUCTION SITE CALCULATIONS
10-YEAR STORM EVENT

15
Type III 24-hr 10-yr Rainfall=8.19"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 7HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 1EX: Site
Runoff = 10.96 cfs @ 12.03 hrs, Volume= 29,181 cf, Depth= 3.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
42,492 76 Woods/grass comb., Fair, HSG C
* 6,800 98 Ex. Road
48,244 43 Woods/grass comb., Fair, HSG A
97,536 61 Weighted Average
90,736 93.03% Pervious Area
6,800 6.97% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.5 296 0.0470 3.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 1EX: Site
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)12
11
10
9
8
7
6
5
4
3
2
1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=97,536 sf
Runoff Volume=29,181 cf
Runoff Depth=3.59"
Flow Length=296'
Slope=0.0470 '/'
Tc=1.5 min
CN=61
10.96 cfs
16
Type III 24-hr 10-yr Rainfall=8.19"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 8HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2EX: Offsite
Runoff = 2.90 cfs @ 12.05 hrs, Volume= 9,691 cf, Depth= 1.63"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=71,247 sf
Runoff Volume=9,691 cf
Runoff Depth=1.63"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
2.90 cfs
17
Type III 24-hr 10-yr Rainfall=8.19"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 9HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Link PRE: Preconstruction Site Discharge
Inflow Area = 168,783 sf, 8.82% Impervious, Inflow Depth = 2.76" for 10-yr event
Inflow = 13.73 cfs @ 12.03 hrs, Volume= 38,872 cf
Primary = 13.73 cfs @ 12.03 hrs, Volume= 38,872 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link PRE: Preconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=168,783 sf
13.73 cfs13.73 cfs
18

PRECONSTRUCTION SITE CALCULATIONS
25-YEAR STORM EVENT

19
Type III 24-hr 25-yr Rainfall=9.68"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 10HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 1EX: Site
Runoff = 14.71 cfs @ 12.02 hrs, Volume= 38,777 cf, Depth= 4.77"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
42,492 76 Woods/grass comb., Fair, HSG C
* 6,800 98 Ex. Road
48,244 43 Woods/grass comb., Fair, HSG A
97,536 61 Weighted Average
90,736 93.03% Pervious Area
6,800 6.97% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.5 296 0.0470 3.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 1EX: Site
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=97,536 sf
Runoff Volume=38,777 cf
Runoff Depth=4.77"
Flow Length=296'
Slope=0.0470 '/'
Tc=1.5 min
CN=61
14.71 cfs
20
Type III 24-hr 25-yr Rainfall=9.68"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 11HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2EX: Offsite
Runoff = 4.77 cfs @ 12.04 hrs, Volume= 14,461 cf, Depth= 2.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)5
4
3
2
1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=71,247 sf
Runoff Volume=14,461 cf
Runoff Depth=2.44"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
4.77 cfs
21
Type III 24-hr 25-yr Rainfall=9.68"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 12HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Link PRE: Preconstruction Site Discharge
Inflow Area = 168,783 sf, 8.82% Impervious, Inflow Depth = 3.79" for 25-yr event
Inflow = 19.30 cfs @ 12.03 hrs, Volume= 53,237 cf
Primary = 19.30 cfs @ 12.03 hrs, Volume= 53,237 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link PRE: Preconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=168,783 sf
19.30 cfs19.30 cfs
22

PRECONSTRUCTION SITE CALCULATIONS
50-YEAR STORM EVENT

23
Type III 24-hr 50-yr Rainfall=10.90"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 13HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 1EX: Site
Runoff = 17.87 cfs @ 12.02 hrs, Volume= 46,982 cf, Depth= 5.78"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
42,492 76 Woods/grass comb., Fair, HSG C
* 6,800 98 Ex. Road
48,244 43 Woods/grass comb., Fair, HSG A
97,536 61 Weighted Average
90,736 93.03% Pervious Area
6,800 6.97% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.5 296 0.0470 3.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 1EX: Site
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=97,536 sf
Runoff Volume=46,982 cf
Runoff Depth=5.78"
Flow Length=296'
Slope=0.0470 '/'
Tc=1.5 min
CN=61
17.87 cfs
24
Type III 24-hr 50-yr Rainfall=10.90"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 14HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2EX: Offsite
Runoff = 6.46 cfs @ 12.04 hrs, Volume= 18,786 cf, Depth= 3.16"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)7
6
5
4
3
2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=71,247 sf
Runoff Volume=18,786 cf
Runoff Depth=3.16"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
6.46 cfs
25
Type III 24-hr 50-yr Rainfall=10.90"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 15HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Link PRE: Preconstruction Site Discharge
Inflow Area = 168,783 sf, 8.82% Impervious, Inflow Depth = 4.68" for 50-yr event
Inflow = 24.12 cfs @ 12.03 hrs, Volume= 65,768 cf
Primary = 24.12 cfs @ 12.03 hrs, Volume= 65,768 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link PRE: Preconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=168,783 sf
24.12 cfs24.12 cfs
26

PRECONSTRUCTION SITE CALCULATIONS
100-YEAR STORM EVENT

27
Type III 24-hr 100-yr Rainfall=12.10"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 16HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 1EX: Site
Runoff = 21.03 cfs @ 12.02 hrs, Volume= 55,290 cf, Depth= 6.80"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
42,492 76 Woods/grass comb., Fair, HSG C
* 6,800 98 Ex. Road
48,244 43 Woods/grass comb., Fair, HSG A
97,536 61 Weighted Average
90,736 93.03% Pervious Area
6,800 6.97% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.5 296 0.0470 3.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 1EX: Site
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=97,536 sf
Runoff Volume=55,290 cf
Runoff Depth=6.80"
Flow Length=296'
Slope=0.0470 '/'
Tc=1.5 min
CN=61
21.03 cfs
28
Type III 24-hr 100-yr Rainfall=12.10"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 17HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2EX: Offsite
Runoff = 8.23 cfs @ 12.04 hrs, Volume= 23,347 cf, Depth= 3.93"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)9
8
7
6
5
4
3
2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=71,247 sf
Runoff Volume=23,347 cf
Runoff Depth=3.93"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
8.23 cfs
29
Type III 24-hr 100-yr Rainfall=12.10"Highlands Preconstruction
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 18HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Link PRE: Preconstruction Site Discharge
Inflow Area = 168,783 sf, 8.82% Impervious, Inflow Depth = 5.59" for 100-yr event
Inflow = 29.03 cfs @ 12.03 hrs, Volume= 78,636 cf
Primary = 29.03 cfs @ 12.03 hrs, Volume= 78,636 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link PRE: Preconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=168,783 sf
29.03 cfs29.03 cfs
30

APPENDIX B
POSTCONSTRUCTION SITE CALCULATIONS

31
Broadway Civil Designs of NC, PLLC
216 Westside Square • Huntsville, AL 35801
Phone: [phone] • Fax: [phone]
32
Broadway Civil Designs of NC, PLLC
216 Westside Square • Huntsville, AL 35801
Phone: [phone] • Fax: [phone]
1S
Roof
2EX
Offsite
2S
Delivery/Dumpster Area
3S
North Parking/Driveway
4S
East Driveway Aisle
5S
Front Parking Area to
GI2
6S
Front Parking Area to
GI1
7S
Septic Area
8S
NW Wetland Area
9S
Cherrywood
Dr/Driveway
10S
Cashiers Rd. R.O.W.
330XLHD
Cultec detention system
POST
Postconstruction Site
Discharge
33

POSTCONSTRUCTION SITE CALCULATIONS
2-YEAR STORM EVENT

34
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 1HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Roof
Runoff = 1.44 cfs @ 12.02 hrs, Volume= 4,327 cf, Depth= 5.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 9,352 98
9,352 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.5 70 0.0417 2.31 Sheet Flow,
Smooth surfaces n= 0.011 P2= 5.79"
0.5 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 1S: Roof
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=9,352 sf
Runoff Volume=4,327 cf
Runoff Depth=5.55"
Flow Length=70'
Slope=0.0417 '/'
Tc=1.2 min
CN=98
1.44 cfs
35
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 2HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2EX: Offsite
Runoff = 0.60 cfs @ 12.08 hrs, Volume= 3,568 cf, Depth= 0.60"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=71,247 sf
Runoff Volume=3,568 cf
Runoff Depth=0.60"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
0.60 cfs
36
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 3HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Delivery/Dumpster Area
Runoff = 0.51 cfs @ 12.02 hrs, Volume= 1,544 cf, Depth= 5.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 3,337 98
3,337 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.8 124 0.0150 2.49 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.8 124 Total, Increased to minimum Tc = 1.2 min
Subcatchment 2S: Delivery/Dumpster Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=3,337 sf
Runoff Volume=1,544 cf
Runoff Depth=5.55"
Flow Length=124'
Slope=0.0150 '/'
Tc=1.2 min
CN=98
0.51 cfs
37
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 4HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: North Parking/Driveway
Runoff = 0.93 cfs @ 12.02 hrs, Volume= 2,782 cf, Depth= 5.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 6,012 98
6,012 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.7 127 0.0200 2.87 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.7 127 Total, Increased to minimum Tc = 1.2 min
Subcatchment 3S: North Parking/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=6,012 sf
Runoff Volume=2,782 cf
Runoff Depth=5.55"
Flow Length=127'
Slope=0.0200 '/'
Tc=1.2 min
CN=98
0.93 cfs
38
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 5HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: East Driveway Aisle
Runoff = 0.47 cfs @ 12.02 hrs, Volume= 1,424 cf, Depth= 5.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 3,077 98
3,077 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 108 0.0090 1.93 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.9 108 Total, Increased to minimum Tc = 1.2 min
Subcatchment 4S: East Driveway Aisle
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=3,077 sf
Runoff Volume=1,424 cf
Runoff Depth=5.55"
Flow Length=108'
Slope=0.0090 '/'
Tc=1.2 min
CN=98
0.47 cfs
39
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 6HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Front Parking Area to GI2
Runoff = 0.56 cfs @ 12.02 hrs, Volume= 1,673 cf, Depth= 5.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 3,615 98
3,615 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.4 70 0.0170 2.65 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.4 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 5S: Front Parking Area to GI2
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=3,615 sf
Runoff Volume=1,673 cf
Runoff Depth=5.55"
Flow Length=70'
Slope=0.0170 '/'
Tc=1.2 min
CN=98
0.56 cfs
40
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 7HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Front Parking Area to GI1
Runoff = 0.84 cfs @ 12.03 hrs, Volume= 2,306 cf, Depth= 4.21"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 2,000 60 Avg. of Woods/grass & Newly graded, HSG A
* 4,572 98
6,572 86 Weighted Average
2,000 30.43% Pervious Area
4,572 69.57% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 21 0.2500 0.21 Sheet Flow,
Grass: Bermuda n= 0.410 P2= 5.79"
0.5 51 0.0080 1.82 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
2.2 72 Total
Subcatchment 6S: Front Parking Area to GI1
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=6,572 sf
Runoff Volume=2,306 cf
Runoff Depth=4.21"
Flow Length=72'
Tc=2.2 min
CN=86
0.84 cfs
41
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 8HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Septic Area
Runoff = 0.25 cfs @ 12.05 hrs, Volume= 1,150 cf, Depth= 0.72"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 2,401 60 Avg. of Woods/Grass & Newly graded, HSG A
16,794 43 Woods/grass comb., Fair, HSG A
19,195 45 Weighted Average
19,195 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 230 0.0730 4.05 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
0.9 230 Total, Increased to minimum Tc = 1.2 min
Subcatchment 7S: Septic Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.26
0.24
0.22
0.2
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=19,195 sf
Runoff Volume=1,150 cf
Runoff Depth=0.72"
Flow Length=230'
Slope=0.0730 '/'
Tc=1.2 min
CN=45
0.25 cfs
42
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 9HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: NW Wetland Area
Runoff = 0.82 cfs @ 12.05 hrs, Volume= 2,420 cf, Depth= 1.79"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 778 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 2,022 83 Avg. of Woods/Grass & Newly Graded, HSG C
8,086 43 Woods/grass comb., Fair, HSG A
5,379 76 Woods/grass comb., Fair, HSG C
16,265 60 Weighted Average
16,265 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
3.0 226 0.0070 1.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 8S: NW Wetland Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=16,265 sf
Runoff Volume=2,420 cf
Runoff Depth=1.79"
Flow Length=226'
Slope=0.0070 '/'
Tc=3.0 min
CN=60
0.82 cfs
43
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 10HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 9S: Cherrywood Dr/Driveway
Runoff = 2.06 cfs @ 12.03 hrs, Volume= 5,556 cf, Depth= 3.69"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 2,293 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,911 83 Avg. of Woods/Grass & Newly Graded, HSG C
* 4,578 98
6,273 76 Woods/grass comb., Fair, HSG C
18,055 81 Weighted Average
13,477 74.64% Pervious Area
4,578 25.36% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.0 256 0.0200 2.12 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 9S: Cherrywood Dr/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=18,055 sf
Runoff Volume=5,556 cf
Runoff Depth=3.69"
Flow Length=256'
Slope=0.0200 '/'
Tc=2.0 min
CN=81
2.06 cfs
44
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 11HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff = 0.94 cfs @ 12.03 hrs, Volume= 2,562 cf, Depth= 2.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 2-yr Rainfall=5.79"
Area (sf) CN Description
* 5,016 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,208 98
2,833 43 Woods/grass comb., Fair, HSG A
12,057 69 Weighted Average
7,849 65.10% Pervious Area
4,208 34.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 383 0.0430 3.11 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
2-yr Rainfall=5.79"
Runoff Area=12,057 sf
Runoff Volume=2,562 cf
Runoff Depth=2.55"
Flow Length=383'
Slope=0.0430 '/'
Tc=2.1 min
CN=69
0.94 cfs
45
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
Printed 9/25/2019Prepared by Broadway Management, LLC
Page 12HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Pond 330XLHD: Cultec detention system
Inflow Area = 31,965 sf, 93.74% Impervious, Inflow Depth = 5.28" for 2-yr event
Inflow = 4.72 cfs @ 12.02 hrs, Volume= 14,054 cf
Outflow = 3.50 cfs @ 12.07 hrs, Volume= 14,054 cf, Atten= 26%, Lag= 3.1 min
Primary = 3.50 cfs @ 12.07 hrs, Volume= 14,054 cf
Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Peak Elev= 4,018.75' @ 12.07 hrs Surf.Area= 2,321 sf Storage= 952 cf
Plug-Flow detention time= 4.2 min calculated for 14,050 cf (100% of inflow)
Center-of-Mass det. time= 4.2 min ( 754.3 - 750.1 )
Volume Invert Avail.Storage Storage Description
#1A 4,018.00' 1,933 cf 20.83'W x 108.50'L x 3.54'H Field A
8,006 cf Overall - 3,174 cf Embedded = 4,832 cf x 40.0% Voids
#2A 4,018.50' 3,174 cf Cultec R-330XLHD x 60 Inside #1
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
#3 4,018.00' 16 cf 18.0" Round 9 L.F. 18" HDPE
L= 9.0' S= 0.0050 '/'
#4 4,018.50' 9 cf 18.0" Round 5 L.F. 18" HDPE
L= 5.0' S= 0.0100 '/'
#5 4,018.55' 81 cf 4.00'D x 6.42'H JB1
#6 4,018.65' 92 cf 18.0" Round 52 L.F. 18" HDPE
L= 52.0' S= 0.0100 '/'
#7 4,018.65' 41 cf 18.0" Round 23 L.F. 18" HDPE
L= 23.0' S= 0.0100 '/'
#8 4,018.92' 58 cf 4.00'D x 4.65'H JB2
#9 4,019.02' 62 cf 18.0" Round 35 L.F. 18" HDPE
L= 35.0' S= 0.0100 '/'
#10 4,019.21' 70 cf 4.00'D x 5.57'H GI2
#11 4,019.31' 138 cf 18.0" Round 78 L.F. 18" HDPE
L= 78.0' S= 0.0100 '/'
#12 4,019.41' 59 cf 4.00'D x 4.70'H GI6
#13 4,019.51' 131 cf 18.0" Round 74 L.F. 18" HDPE
L= 74.0' S= 0.0100 '/'
#14 4,020.13' 58 cf 4.00'D x 4.63'H GI1
#15 4,020.29' 39 cf 4.00'D x 3.08'H GI5
#16 4,018.55' 65 cf 4.00'D x 5.21'H GI4
#17 4,018.65' 97 cf 18.0" Round 55 L.F. 18" HDPE
L= 55.0' S= 0.0100 '/'
#18 4,019.24' 63 cf 4.00'D x 5.00'H GI3
6,185 cf Total Available Storage
Storage Group A created with Chamber Wizard
46
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
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Device Routing Invert Outlet Devices
#1 Primary 4,017.85'18.0" Round Culvert L= 14.0' Ke= 0.500
Inlet / Outlet Invert= 4,017.85' / 4,017.77' S= 0.0057 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Primary 4,017.95'6.0" W x 6.0" H Vert. Orifice C= 0.600
#3 Primary 4,020.50'1.5' long Weir 2 End Contraction(s) 1.0' Crest Height
#4 Primary 4,021.50'5.0' long Top of Wall 2 End Contraction(s)
Primary OutFlow Max=3.50 cfs @ 12.07 hrs HW=4,018.75' (Free Discharge)
1=Culvert (Barrel Controls 2.61 cfs @ 3.37 fps)
2=Orifice (Orifice Controls 0.89 cfs @ 3.55 fps)
3=Weir ( Controls 0.00 cfs)
4=Top of Wall ( Controls 0.00 cfs)
47
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
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Pond 330XLHD: Cultec detention system - Chamber Wizard Field A
Chamber Model = Cultec R-330XLHD (Cultec Recharger® 330XLHD)
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
52.0" Wide + 6.0" Spacing = 58.0" C-C Row Spacing
15 Chambers/Row x 7.00' Long +1.50' Row Adjustment = 106.50' Row Length +12.0" End Stone x 2 =
108.50' Base Length
4 Rows x 52.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 20.83' Base Width
6.0" Base + 30.5" Chamber Height + 6.0" Cover = 3.54' Field Height
60 Chambers x 52.2 cf +1.50' Row Adjustment x 7.45 sf x 4 Rows = 3,174.1 cf Chamber Storage
8,005.6 cf Field - 3,174.1 cf Chambers = 4,831.5 cf Stone x 40.0% Voids = 1,932.6 cf Stone Storage
Chamber Storage + Stone Storage = 5,106.7 cf = 0.117 af
Overall Storage Efficiency = 63.8%
Overall System Size = 108.50' x 20.83' x 3.54'
60 Chambers
296.5 cy Field
178.9 cy Stone
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Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
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Page 15HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Pond 330XLHD: Cultec detention system
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)5
4
3
2
1
0
Inflow Area=31,965 sf
Peak Elev=4,018.75'
Storage=952 cf
4.72 cfs
3.50 cfs
49
Type III 24-hr 2-yr Rainfall=5.79"Highlands Postconstruction wChambers
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Page 16HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Link POST: Postconstruction Site Discharge
Inflow Area = 168,784 sf, 27.75% Impervious, Inflow Depth = 2.08" for 2-yr event
Inflow = 7.87 cfs @ 12.05 hrs, Volume= 29,311 cf
Primary = 7.87 cfs @ 12.05 hrs, Volume= 29,311 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link POST: Postconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)8
7
6
5
4
3
2
1
0
Inflow Area=168,784 sf
7.87 cfs7.87 cfs
50

POSTCONSTRUCTION SITE CALCULATIONS
5-YEAR STORM EVENT

51
Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 1S: Roof
Runoff = 1.78 cfs @ 12.02 hrs, Volume= 5,370 cf, Depth= 6.89"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 9,352 98
9,352 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.5 70 0.0417 2.31 Sheet Flow,
Smooth surfaces n= 0.011 P2= 5.79"
0.5 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 1S: Roof
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=9,352 sf
Runoff Volume=5,370 cf
Runoff Depth=6.89"
Flow Length=70'
Slope=0.0417 '/'
Tc=1.2 min
CN=98
1.78 cfs
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Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 2EX: Offsite
Runoff = 1.75 cfs @ 12.05 hrs, Volume= 6,716 cf, Depth= 1.13"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=71,247 sf
Runoff Volume=6,716 cf
Runoff Depth=1.13"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
1.75 cfs
53
Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 2S: Delivery/Dumpster Area
Runoff = 0.63 cfs @ 12.02 hrs, Volume= 1,916 cf, Depth= 6.89"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 3,337 98
3,337 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.8 124 0.0150 2.49 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.8 124 Total, Increased to minimum Tc = 1.2 min
Subcatchment 2S: Delivery/Dumpster Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=3,337 sf
Runoff Volume=1,916 cf
Runoff Depth=6.89"
Flow Length=124'
Slope=0.0150 '/'
Tc=1.2 min
CN=98
0.63 cfs
54
Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 3S: North Parking/Driveway
Runoff = 1.14 cfs @ 12.02 hrs, Volume= 3,452 cf, Depth= 6.89"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 6,012 98
6,012 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.7 127 0.0200 2.87 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.7 127 Total, Increased to minimum Tc = 1.2 min
Subcatchment 3S: North Parking/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=6,012 sf
Runoff Volume=3,452 cf
Runoff Depth=6.89"
Flow Length=127'
Slope=0.0200 '/'
Tc=1.2 min
CN=98
1.14 cfs
55
Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 4S: East Driveway Aisle
Runoff = 0.59 cfs @ 12.02 hrs, Volume= 1,767 cf, Depth= 6.89"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 3,077 98
3,077 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 108 0.0090 1.93 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.9 108 Total, Increased to minimum Tc = 1.2 min
Subcatchment 4S: East Driveway Aisle
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=3,077 sf
Runoff Volume=1,767 cf
Runoff Depth=6.89"
Flow Length=108'
Slope=0.0090 '/'
Tc=1.2 min
CN=98
0.59 cfs
56
Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 5S: Front Parking Area to GI2
Runoff = 0.69 cfs @ 12.02 hrs, Volume= 2,076 cf, Depth= 6.89"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 3,615 98
3,615 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.4 70 0.0170 2.65 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.4 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 5S: Front Parking Area to GI2
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=3,615 sf
Runoff Volume=2,076 cf
Runoff Depth=6.89"
Flow Length=70'
Slope=0.0170 '/'
Tc=1.2 min
CN=98
0.69 cfs
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Summary for Subcatchment 6S: Front Parking Area to GI1
Runoff = 1.08 cfs @ 12.03 hrs, Volume= 3,007 cf, Depth= 5.49"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 2,000 60 Avg. of Woods/grass & Newly graded, HSG A
* 4,572 98
6,572 86 Weighted Average
2,000 30.43% Pervious Area
4,572 69.57% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 21 0.2500 0.21 Sheet Flow,
Grass: Bermuda n= 0.410 P2= 5.79"
0.5 51 0.0080 1.82 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
2.2 72 Total
Subcatchment 6S: Front Parking Area to GI1
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=6,572 sf
Runoff Volume=3,007 cf
Runoff Depth=5.49"
Flow Length=72'
Tc=2.2 min
CN=86
1.08 cfs
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Summary for Subcatchment 7S: Septic Area
Runoff = 0.61 cfs @ 12.03 hrs, Volume= 2,077 cf, Depth= 1.30"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 2,401 60 Avg. of Woods/Grass & Newly graded, HSG A
16,794 43 Woods/grass comb., Fair, HSG A
19,195 45 Weighted Average
19,195 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 230 0.0730 4.05 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
0.9 230 Total, Increased to minimum Tc = 1.2 min
Subcatchment 7S: Septic Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=19,195 sf
Runoff Volume=2,077 cf
Runoff Depth=1.30"
Flow Length=230'
Slope=0.0730 '/'
Tc=1.2 min
CN=45
0.61 cfs
59
Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 8S: NW Wetland Area
Runoff = 1.28 cfs @ 12.05 hrs, Volume= 3,654 cf, Depth= 2.70"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 778 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 2,022 83 Avg. of Woods/Grass & Newly Graded, HSG C
8,086 43 Woods/grass comb., Fair, HSG A
5,379 76 Woods/grass comb., Fair, HSG C
16,265 60 Weighted Average
16,265 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
3.0 226 0.0070 1.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 8S: NW Wetland Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=16,265 sf
Runoff Volume=3,654 cf
Runoff Depth=2.70"
Flow Length=226'
Slope=0.0070 '/'
Tc=3.0 min
CN=60
1.28 cfs
60
Type III 24-hr 5-yr Rainfall=7.13"Highlands Postconstruction wChambers
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Summary for Subcatchment 9S: Cherrywood Dr/Driveway
Runoff = 2.73 cfs @ 12.03 hrs, Volume= 7,412 cf, Depth= 4.93"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 2,293 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,911 83 Avg. of Woods/Grass & Newly Graded, HSG C
* 4,578 98
6,273 76 Woods/grass comb., Fair, HSG C
18,055 81 Weighted Average
13,477 74.64% Pervious Area
4,578 25.36% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.0 256 0.0200 2.12 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 9S: Cherrywood Dr/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=18,055 sf
Runoff Volume=7,412 cf
Runoff Depth=4.93"
Flow Length=256'
Slope=0.0200 '/'
Tc=2.0 min
CN=81
2.73 cfs
61
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Summary for Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff = 1.35 cfs @ 12.03 hrs, Volume= 3,638 cf, Depth= 3.62"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 5-yr Rainfall=7.13"
Area (sf) CN Description
* 5,016 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,208 98
2,833 43 Woods/grass comb., Fair, HSG A
12,057 69 Weighted Average
7,849 65.10% Pervious Area
4,208 34.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 383 0.0430 3.11 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
5-yr Rainfall=7.13"
Runoff Area=12,057 sf
Runoff Volume=3,638 cf
Runoff Depth=3.62"
Flow Length=383'
Slope=0.0430 '/'
Tc=2.1 min
CN=69
1.35 cfs
62
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Summary for Pond 330XLHD: Cultec detention system
Inflow Area = 31,965 sf, 93.74% Impervious, Inflow Depth = 6.60" for 5-yr event
Inflow = 5.87 cfs @ 12.02 hrs, Volume= 17,589 cf
Outflow = 4.32 cfs @ 12.07 hrs, Volume= 17,589 cf, Atten= 26%, Lag= 3.1 min
Primary = 4.32 cfs @ 12.07 hrs, Volume= 17,589 cf
Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Peak Elev= 4,018.89' @ 12.07 hrs Surf.Area= 2,360 sf Storage= 1,222 cf
Plug-Flow detention time= 4.2 min calculated for 17,583 cf (100% of inflow)
Center-of-Mass det. time= 4.2 min ( 751.0 - 746.8 )
Volume Invert Avail.Storage Storage Description
#1A 4,018.00' 1,933 cf 20.83'W x 108.50'L x 3.54'H Field A
8,006 cf Overall - 3,174 cf Embedded = 4,832 cf x 40.0% Voids
#2A 4,018.50' 3,174 cf Cultec R-330XLHD x 60 Inside #1
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
#3 4,018.00' 16 cf 18.0" Round 9 L.F. 18" HDPE
L= 9.0' S= 0.0050 '/'
#4 4,018.50' 9 cf 18.0" Round 5 L.F. 18" HDPE
L= 5.0' S= 0.0100 '/'
#5 4,018.55' 81 cf 4.00'D x 6.42'H JB1
#6 4,018.65' 92 cf 18.0" Round 52 L.F. 18" HDPE
L= 52.0' S= 0.0100 '/'
#7 4,018.65' 41 cf 18.0" Round 23 L.F. 18" HDPE
L= 23.0' S= 0.0100 '/'
#8 4,018.92' 58 cf 4.00'D x 4.65'H JB2
#9 4,019.02' 62 cf 18.0" Round 35 L.F. 18" HDPE
L= 35.0' S= 0.0100 '/'
#10 4,019.21' 70 cf 4.00'D x 5.57'H GI2
#11 4,019.31' 138 cf 18.0" Round 78 L.F. 18" HDPE
L= 78.0' S= 0.0100 '/'
#12 4,019.41' 59 cf 4.00'D x 4.70'H GI6
#13 4,019.51' 131 cf 18.0" Round 74 L.F. 18" HDPE
L= 74.0' S= 0.0100 '/'
#14 4,020.13' 58 cf 4.00'D x 4.63'H GI1
#15 4,020.29' 39 cf 4.00'D x 3.08'H GI5
#16 4,018.55' 65 cf 4.00'D x 5.21'H GI4
#17 4,018.65' 97 cf 18.0" Round 55 L.F. 18" HDPE
L= 55.0' S= 0.0100 '/'
#18 4,019.24' 63 cf 4.00'D x 5.00'H GI3
6,185 cf Total Available Storage
Storage Group A created with Chamber Wizard
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Device Routing Invert Outlet Devices
#1 Primary 4,017.85'18.0" Round Culvert L= 14.0' Ke= 0.500
Inlet / Outlet Invert= 4,017.85' / 4,017.77' S= 0.0057 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Primary 4,017.95'6.0" W x 6.0" H Vert. Orifice C= 0.600
#3 Primary 4,020.50'1.5' long Weir 2 End Contraction(s) 1.0' Crest Height
#4 Primary 4,021.50'5.0' long Top of Wall 2 End Contraction(s)
Primary OutFlow Max=4.32 cfs @ 12.07 hrs HW=4,018.89' (Free Discharge)
1=Culvert (Barrel Controls 3.32 cfs @ 3.58 fps)
2=Orifice (Orifice Controls 0.99 cfs @ 3.98 fps)
3=Weir ( Controls 0.00 cfs)
4=Top of Wall ( Controls 0.00 cfs)
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Pond 330XLHD: Cultec detention system - Chamber Wizard Field A
Chamber Model = Cultec R-330XLHD (Cultec Recharger® 330XLHD)
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
52.0" Wide + 6.0" Spacing = 58.0" C-C Row Spacing
15 Chambers/Row x 7.00' Long +1.50' Row Adjustment = 106.50' Row Length +12.0" End Stone x 2 =
108.50' Base Length
4 Rows x 52.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 20.83' Base Width
6.0" Base + 30.5" Chamber Height + 6.0" Cover = 3.54' Field Height
60 Chambers x 52.2 cf +1.50' Row Adjustment x 7.45 sf x 4 Rows = 3,174.1 cf Chamber Storage
8,005.6 cf Field - 3,174.1 cf Chambers = 4,831.5 cf Stone x 40.0% Voids = 1,932.6 cf Stone Storage
Chamber Storage + Stone Storage = 5,106.7 cf = 0.117 af
Overall Storage Efficiency = 63.8%
Overall System Size = 108.50' x 20.83' x 3.54'
60 Chambers
296.5 cy Field
178.9 cy Stone
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Pond 330XLHD: Cultec detention system
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)6
5
4
3
2
1
0
Inflow Area=31,965 sf
Peak Elev=4,018.89'
Storage=1,222 cf
5.87 cfs
4.32 cfs
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Summary for Link POST: Postconstruction Site Discharge
Inflow Area = 168,784 sf, 27.75% Impervious, Inflow Depth = 2.92" for 5-yr event
Inflow = 11.72 cfs @ 12.05 hrs, Volume= 41,085 cf
Primary = 11.72 cfs @ 12.05 hrs, Volume= 41,085 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link POST: Postconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=168,784 sf
11.72 cfs11.72 cfs
67

POSTCONSTRUCTION SITE CALCULATIONS
10-YEAR STORM EVENT

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Summary for Subcatchment 1S: Roof
Runoff = 2.04 cfs @ 12.02 hrs, Volume= 6,196 cf, Depth= 7.95"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 9,352 98
9,352 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.5 70 0.0417 2.31 Sheet Flow,
Smooth surfaces n= 0.011 P2= 5.79"
0.5 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 1S: Roof
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=9,352 sf
Runoff Volume=6,196 cf
Runoff Depth=7.95"
Flow Length=70'
Slope=0.0417 '/'
Tc=1.2 min
CN=98
2.04 cfs
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Summary for Subcatchment 2EX: Offsite
Runoff = 2.90 cfs @ 12.05 hrs, Volume= 9,691 cf, Depth= 1.63"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=71,247 sf
Runoff Volume=9,691 cf
Runoff Depth=1.63"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
2.90 cfs
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Summary for Subcatchment 2S: Delivery/Dumpster Area
Runoff = 0.73 cfs @ 12.02 hrs, Volume= 2,211 cf, Depth= 7.95"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 3,337 98
3,337 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.8 124 0.0150 2.49 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.8 124 Total, Increased to minimum Tc = 1.2 min
Subcatchment 2S: Delivery/Dumpster Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=3,337 sf
Runoff Volume=2,211 cf
Runoff Depth=7.95"
Flow Length=124'
Slope=0.0150 '/'
Tc=1.2 min
CN=98
0.73 cfs
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Summary for Subcatchment 3S: North Parking/Driveway
Runoff = 1.31 cfs @ 12.02 hrs, Volume= 3,983 cf, Depth= 7.95"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 6,012 98
6,012 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.7 127 0.0200 2.87 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.7 127 Total, Increased to minimum Tc = 1.2 min
Subcatchment 3S: North Parking/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=6,012 sf
Runoff Volume=3,983 cf
Runoff Depth=7.95"
Flow Length=127'
Slope=0.0200 '/'
Tc=1.2 min
CN=98
1.31 cfs
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Summary for Subcatchment 4S: East Driveway Aisle
Runoff = 0.67 cfs @ 12.02 hrs, Volume= 2,039 cf, Depth= 7.95"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 3,077 98
3,077 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 108 0.0090 1.93 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.9 108 Total, Increased to minimum Tc = 1.2 min
Subcatchment 4S: East Driveway Aisle
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=3,077 sf
Runoff Volume=2,039 cf
Runoff Depth=7.95"
Flow Length=108'
Slope=0.0090 '/'
Tc=1.2 min
CN=98
0.67 cfs
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Summary for Subcatchment 5S: Front Parking Area to GI2
Runoff = 0.79 cfs @ 12.02 hrs, Volume= 2,395 cf, Depth= 7.95"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 3,615 98
3,615 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.4 70 0.0170 2.65 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.4 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 5S: Front Parking Area to GI2
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.85
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=3,615 sf
Runoff Volume=2,395 cf
Runoff Depth=7.95"
Flow Length=70'
Slope=0.0170 '/'
Tc=1.2 min
CN=98
0.79 cfs
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Summary for Subcatchment 6S: Front Parking Area to GI1
Runoff = 1.27 cfs @ 12.03 hrs, Volume= 3,568 cf, Depth= 6.52"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 2,000 60 Avg. of Woods/grass & Newly graded, HSG A
* 4,572 98
6,572 86 Weighted Average
2,000 30.43% Pervious Area
4,572 69.57% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 21 0.2500 0.21 Sheet Flow,
Grass: Bermuda n= 0.410 P2= 5.79"
0.5 51 0.0080 1.82 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
2.2 72 Total
Subcatchment 6S: Front Parking Area to GI1
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=6,572 sf
Runoff Volume=3,568 cf
Runoff Depth=6.52"
Flow Length=72'
Tc=2.2 min
CN=86
1.27 cfs
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Summary for Subcatchment 7S: Septic Area
Runoff = 0.95 cfs @ 12.03 hrs, Volume= 2,939 cf, Depth= 1.84"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 2,401 60 Avg. of Woods/Grass & Newly graded, HSG A
16,794 43 Woods/grass comb., Fair, HSG A
19,195 45 Weighted Average
19,195 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 230 0.0730 4.05 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
0.9 230 Total, Increased to minimum Tc = 1.2 min
Subcatchment 7S: Septic Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=19,195 sf
Runoff Volume=2,939 cf
Runoff Depth=1.84"
Flow Length=230'
Slope=0.0730 '/'
Tc=1.2 min
CN=45
0.95 cfs
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Summary for Subcatchment 8S: NW Wetland Area
Runoff = 1.68 cfs @ 12.05 hrs, Volume= 4,712 cf, Depth= 3.48"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 778 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 2,022 83 Avg. of Woods/Grass & Newly Graded, HSG C
8,086 43 Woods/grass comb., Fair, HSG A
5,379 76 Woods/grass comb., Fair, HSG C
16,265 60 Weighted Average
16,265 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
3.0 226 0.0070 1.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 8S: NW Wetland Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=16,265 sf
Runoff Volume=4,712 cf
Runoff Depth=3.48"
Flow Length=226'
Slope=0.0070 '/'
Tc=3.0 min
CN=60
1.68 cfs
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Summary for Subcatchment 9S: Cherrywood Dr/Driveway
Runoff = 3.26 cfs @ 12.03 hrs, Volume= 8,910 cf, Depth= 5.92"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 2,293 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,911 83 Avg. of Woods/Grass & Newly Graded, HSG C
* 4,578 98
6,273 76 Woods/grass comb., Fair, HSG C
18,055 81 Weighted Average
13,477 74.64% Pervious Area
4,578 25.36% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.0 256 0.0200 2.12 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 9S: Cherrywood Dr/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=18,055 sf
Runoff Volume=8,910 cf
Runoff Depth=5.92"
Flow Length=256'
Slope=0.0200 '/'
Tc=2.0 min
CN=81
3.26 cfs
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Summary for Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff = 1.69 cfs @ 12.03 hrs, Volume= 4,533 cf, Depth= 4.51"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 10-yr Rainfall=8.19"
Area (sf) CN Description
* 5,016 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,208 98
2,833 43 Woods/grass comb., Fair, HSG A
12,057 69 Weighted Average
7,849 65.10% Pervious Area
4,208 34.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 383 0.0430 3.11 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
10-yr Rainfall=8.19"
Runoff Area=12,057 sf
Runoff Volume=4,533 cf
Runoff Depth=4.51"
Flow Length=383'
Slope=0.0430 '/'
Tc=2.1 min
CN=69
1.69 cfs
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Summary for Pond 330XLHD: Cultec detention system
Inflow Area = 31,965 sf, 93.74% Impervious, Inflow Depth = 7.66" for 10-yr event
Inflow = 6.78 cfs @ 12.02 hrs, Volume= 20,391 cf
Outflow = 4.99 cfs @ 12.07 hrs, Volume= 20,391 cf, Atten= 26%, Lag= 3.1 min
Primary = 4.99 cfs @ 12.07 hrs, Volume= 20,391 cf
Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Peak Elev= 4,019.00' @ 12.07 hrs Surf.Area= 2,405 sf Storage= 1,439 cf
Plug-Flow detention time= 4.3 min calculated for 20,385 cf (100% of inflow)
Center-of-Mass det. time= 4.3 min ( 749.0 - 744.7 )
Volume Invert Avail.Storage Storage Description
#1A 4,018.00' 1,933 cf 20.83'W x 108.50'L x 3.54'H Field A
8,006 cf Overall - 3,174 cf Embedded = 4,832 cf x 40.0% Voids
#2A 4,018.50' 3,174 cf Cultec R-330XLHD x 60 Inside #1
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
#3 4,018.00' 16 cf 18.0" Round 9 L.F. 18" HDPE
L= 9.0' S= 0.0050 '/'
#4 4,018.50' 9 cf 18.0" Round 5 L.F. 18" HDPE
L= 5.0' S= 0.0100 '/'
#5 4,018.55' 81 cf 4.00'D x 6.42'H JB1
#6 4,018.65' 92 cf 18.0" Round 52 L.F. 18" HDPE
L= 52.0' S= 0.0100 '/'
#7 4,018.65' 41 cf 18.0" Round 23 L.F. 18" HDPE
L= 23.0' S= 0.0100 '/'
#8 4,018.92' 58 cf 4.00'D x 4.65'H JB2
#9 4,019.02' 62 cf 18.0" Round 35 L.F. 18" HDPE
L= 35.0' S= 0.0100 '/'
#10 4,019.21' 70 cf 4.00'D x 5.57'H GI2
#11 4,019.31' 138 cf 18.0" Round 78 L.F. 18" HDPE
L= 78.0' S= 0.0100 '/'
#12 4,019.41' 59 cf 4.00'D x 4.70'H GI6
#13 4,019.51' 131 cf 18.0" Round 74 L.F. 18" HDPE
L= 74.0' S= 0.0100 '/'
#14 4,020.13' 58 cf 4.00'D x 4.63'H GI1
#15 4,020.29' 39 cf 4.00'D x 3.08'H GI5
#16 4,018.55' 65 cf 4.00'D x 5.21'H GI4
#17 4,018.65' 97 cf 18.0" Round 55 L.F. 18" HDPE
L= 55.0' S= 0.0100 '/'
#18 4,019.24' 63 cf 4.00'D x 5.00'H GI3
6,185 cf Total Available Storage
Storage Group A created with Chamber Wizard
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Device Routing Invert Outlet Devices
#1 Primary 4,017.85'18.0" Round Culvert L= 14.0' Ke= 0.500
Inlet / Outlet Invert= 4,017.85' / 4,017.77' S= 0.0057 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Primary 4,017.95'6.0" W x 6.0" H Vert. Orifice C= 0.600
#3 Primary 4,020.50'1.5' long Weir 2 End Contraction(s) 1.0' Crest Height
#4 Primary 4,021.50'5.0' long Top of Wall 2 End Contraction(s)
Primary OutFlow Max=4.99 cfs @ 12.07 hrs HW=4,019.00' (Free Discharge)
1=Culvert (Barrel Controls 3.92 cfs @ 3.73 fps)
2=Orifice (Orifice Controls 1.07 cfs @ 4.28 fps)
3=Weir ( Controls 0.00 cfs)
4=Top of Wall ( Controls 0.00 cfs)
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Page 46HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Pond 330XLHD: Cultec detention system - Chamber Wizard Field A
Chamber Model = Cultec R-330XLHD (Cultec Recharger® 330XLHD)
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
52.0" Wide + 6.0" Spacing = 58.0" C-C Row Spacing
15 Chambers/Row x 7.00' Long +1.50' Row Adjustment = 106.50' Row Length +12.0" End Stone x 2 =
108.50' Base Length
4 Rows x 52.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 20.83' Base Width
6.0" Base + 30.5" Chamber Height + 6.0" Cover = 3.54' Field Height
60 Chambers x 52.2 cf +1.50' Row Adjustment x 7.45 sf x 4 Rows = 3,174.1 cf Chamber Storage
8,005.6 cf Field - 3,174.1 cf Chambers = 4,831.5 cf Stone x 40.0% Voids = 1,932.6 cf Stone Storage
Chamber Storage + Stone Storage = 5,106.7 cf = 0.117 af
Overall Storage Efficiency = 63.8%
Overall System Size = 108.50' x 20.83' x 3.54'
60 Chambers
296.5 cy Field
178.9 cy Stone
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Pond 330XLHD: Cultec detention system
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)7
6
5
4
3
2
1
0
Inflow Area=31,965 sf
Peak Elev=4,019.00'
Storage=1,439 cf
6.78 cfs
4.99 cfs
83
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Summary for Link POST: Postconstruction Site Discharge
Inflow Area = 168,784 sf, 27.75% Impervious, Inflow Depth = 3.64" for 10-yr event
Inflow = 15.10 cfs @ 12.04 hrs, Volume= 51,177 cf
Primary = 15.10 cfs @ 12.04 hrs, Volume= 51,177 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link POST: Postconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=168,784 sf
15.10 cfs15.10 cfs
84

POSTCONSTRUCTION SITE CALCULATIONS
25-YEAR STORM EVENT

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Summary for Subcatchment 1S: Roof
Runoff = 2.42 cfs @ 12.02 hrs, Volume= 7,356 cf, Depth= 9.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 9,352 98
9,352 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.5 70 0.0417 2.31 Sheet Flow,
Smooth surfaces n= 0.011 P2= 5.79"
0.5 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 1S: Roof
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=9,352 sf
Runoff Volume=7,356 cf
Runoff Depth=9.44"
Flow Length=70'
Slope=0.0417 '/'
Tc=1.2 min
CN=98
2.42 cfs
86
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Summary for Subcatchment 2EX: Offsite
Runoff = 4.77 cfs @ 12.04 hrs, Volume= 14,461 cf, Depth= 2.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)5
4
3
2
1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=71,247 sf
Runoff Volume=14,461 cf
Runoff Depth=2.44"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
4.77 cfs
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Summary for Subcatchment 2S: Delivery/Dumpster Area
Runoff = 0.86 cfs @ 12.02 hrs, Volume= 2,625 cf, Depth= 9.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 3,337 98
3,337 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.8 124 0.0150 2.49 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.8 124 Total, Increased to minimum Tc = 1.2 min
Subcatchment 2S: Delivery/Dumpster Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.95
0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=3,337 sf
Runoff Volume=2,625 cf
Runoff Depth=9.44"
Flow Length=124'
Slope=0.0150 '/'
Tc=1.2 min
CN=98
0.86 cfs
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Summary for Subcatchment 3S: North Parking/Driveway
Runoff = 1.55 cfs @ 12.02 hrs, Volume= 4,729 cf, Depth= 9.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 6,012 98
6,012 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.7 127 0.0200 2.87 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.7 127 Total, Increased to minimum Tc = 1.2 min
Subcatchment 3S: North Parking/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=6,012 sf
Runoff Volume=4,729 cf
Runoff Depth=9.44"
Flow Length=127'
Slope=0.0200 '/'
Tc=1.2 min
CN=98
1.55 cfs
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Summary for Subcatchment 4S: East Driveway Aisle
Runoff = 0.80 cfs @ 12.02 hrs, Volume= 2,420 cf, Depth= 9.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 3,077 98
3,077 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 108 0.0090 1.93 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.9 108 Total, Increased to minimum Tc = 1.2 min
Subcatchment 4S: East Driveway Aisle
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)0.85
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=3,077 sf
Runoff Volume=2,420 cf
Runoff Depth=9.44"
Flow Length=108'
Slope=0.0090 '/'
Tc=1.2 min
CN=98
0.80 cfs
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Summary for Subcatchment 5S: Front Parking Area to GI2
Runoff = 0.93 cfs @ 12.02 hrs, Volume= 2,844 cf, Depth= 9.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 3,615 98
3,615 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.4 70 0.0170 2.65 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.4 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 5S: Front Parking Area to GI2
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=3,615 sf
Runoff Volume=2,844 cf
Runoff Depth=9.44"
Flow Length=70'
Slope=0.0170 '/'
Tc=1.2 min
CN=98
0.93 cfs
91
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Summary for Subcatchment 6S: Front Parking Area to GI1
Runoff = 1.53 cfs @ 12.03 hrs, Volume= 4,364 cf, Depth= 7.97"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 2,000 60 Avg. of Woods/grass & Newly graded, HSG A
* 4,572 98
6,572 86 Weighted Average
2,000 30.43% Pervious Area
4,572 69.57% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 21 0.2500 0.21 Sheet Flow,
Grass: Bermuda n= 0.410 P2= 5.79"
0.5 51 0.0080 1.82 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
2.2 72 Total
Subcatchment 6S: Front Parking Area to GI1
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=6,572 sf
Runoff Volume=4,364 cf
Runoff Depth=7.97"
Flow Length=72'
Tc=2.2 min
CN=86
1.53 cfs
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Summary for Subcatchment 7S: Septic Area
Runoff = 1.51 cfs @ 12.02 hrs, Volume= 4,304 cf, Depth= 2.69"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 2,401 60 Avg. of Woods/Grass & Newly graded, HSG A
16,794 43 Woods/grass comb., Fair, HSG A
19,195 45 Weighted Average
19,195 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 230 0.0730 4.05 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
0.9 230 Total, Increased to minimum Tc = 1.2 min
Subcatchment 7S: Septic Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=19,195 sf
Runoff Volume=4,304 cf
Runoff Depth=2.69"
Flow Length=230'
Slope=0.0730 '/'
Tc=1.2 min
CN=45
1.51 cfs
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Summary for Subcatchment 8S: NW Wetland Area
Runoff = 2.26 cfs @ 12.05 hrs, Volume= 6,290 cf, Depth= 4.64"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 778 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 2,022 83 Avg. of Woods/Grass & Newly Graded, HSG C
8,086 43 Woods/grass comb., Fair, HSG A
5,379 76 Woods/grass comb., Fair, HSG C
16,265 60 Weighted Average
16,265 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
3.0 226 0.0070 1.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 8S: NW Wetland Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=16,265 sf
Runoff Volume=6,290 cf
Runoff Depth=4.64"
Flow Length=226'
Slope=0.0070 '/'
Tc=3.0 min
CN=60
2.26 cfs
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Summary for Subcatchment 9S: Cherrywood Dr/Driveway
Runoff = 4.00 cfs @ 12.03 hrs, Volume= 11,046 cf, Depth= 7.34"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 2,293 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,911 83 Avg. of Woods/Grass & Newly Graded, HSG C
* 4,578 98
6,273 76 Woods/grass comb., Fair, HSG C
18,055 81 Weighted Average
13,477 74.64% Pervious Area
4,578 25.36% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.0 256 0.0200 2.12 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 9S: Cherrywood Dr/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)4
3
2
1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=18,055 sf
Runoff Volume=11,046 cf
Runoff Depth=7.34"
Flow Length=256'
Slope=0.0200 '/'
Tc=2.0 min
CN=81
4.00 cfs
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Summary for Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff = 2.17 cfs @ 12.03 hrs, Volume= 5,837 cf, Depth= 5.81"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 25-yr Rainfall=9.68"
Area (sf) CN Description
* 5,016 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,208 98
2,833 43 Woods/grass comb., Fair, HSG A
12,057 69 Weighted Average
7,849 65.10% Pervious Area
4,208 34.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 383 0.0430 3.11 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
25-yr Rainfall=9.68"
Runoff Area=12,057 sf
Runoff Volume=5,837 cf
Runoff Depth=5.81"
Flow Length=383'
Slope=0.0430 '/'
Tc=2.1 min
CN=69
2.17 cfs
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Summary for Pond 330XLHD: Cultec detention system
Inflow Area = 31,965 sf, 93.74% Impervious, Inflow Depth = 9.14" for 25-yr event
Inflow = 8.05 cfs @ 12.02 hrs, Volume= 24,338 cf
Outflow = 5.95 cfs @ 12.07 hrs, Volume= 24,338 cf, Atten= 26%, Lag= 3.1 min
Primary = 5.95 cfs @ 12.07 hrs, Volume= 24,338 cf
Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Peak Elev= 4,019.15' @ 12.07 hrs Surf.Area= 2,457 sf Storage= 1,744 cf
Plug-Flow detention time= 4.3 min calculated for 24,330 cf (100% of inflow)
Center-of-Mass det. time= 4.3 min ( 746.7 - 742.4 )
Volume Invert Avail.Storage Storage Description
#1A 4,018.00' 1,933 cf 20.83'W x 108.50'L x 3.54'H Field A
8,006 cf Overall - 3,174 cf Embedded = 4,832 cf x 40.0% Voids
#2A 4,018.50' 3,174 cf Cultec R-330XLHD x 60 Inside #1
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
#3 4,018.00' 16 cf 18.0" Round 9 L.F. 18" HDPE
L= 9.0' S= 0.0050 '/'
#4 4,018.50' 9 cf 18.0" Round 5 L.F. 18" HDPE
L= 5.0' S= 0.0100 '/'
#5 4,018.55' 81 cf 4.00'D x 6.42'H JB1
#6 4,018.65' 92 cf 18.0" Round 52 L.F. 18" HDPE
L= 52.0' S= 0.0100 '/'
#7 4,018.65' 41 cf 18.0" Round 23 L.F. 18" HDPE
L= 23.0' S= 0.0100 '/'
#8 4,018.92' 58 cf 4.00'D x 4.65'H JB2
#9 4,019.02' 62 cf 18.0" Round 35 L.F. 18" HDPE
L= 35.0' S= 0.0100 '/'
#10 4,019.21' 70 cf 4.00'D x 5.57'H GI2
#11 4,019.31' 138 cf 18.0" Round 78 L.F. 18" HDPE
L= 78.0' S= 0.0100 '/'
#12 4,019.41' 59 cf 4.00'D x 4.70'H GI6
#13 4,019.51' 131 cf 18.0" Round 74 L.F. 18" HDPE
L= 74.0' S= 0.0100 '/'
#14 4,020.13' 58 cf 4.00'D x 4.63'H GI1
#15 4,020.29' 39 cf 4.00'D x 3.08'H GI5
#16 4,018.55' 65 cf 4.00'D x 5.21'H GI4
#17 4,018.65' 97 cf 18.0" Round 55 L.F. 18" HDPE
L= 55.0' S= 0.0100 '/'
#18 4,019.24' 63 cf 4.00'D x 5.00'H GI3
6,185 cf Total Available Storage
Storage Group A created with Chamber Wizard
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Device Routing Invert Outlet Devices
#1 Primary 4,017.85'18.0" Round Culvert L= 14.0' Ke= 0.500
Inlet / Outlet Invert= 4,017.85' / 4,017.77' S= 0.0057 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Primary 4,017.95'6.0" W x 6.0" H Vert. Orifice C= 0.600
#3 Primary 4,020.50'1.5' long Weir 2 End Contraction(s) 1.0' Crest Height
#4 Primary 4,021.50'5.0' long Top of Wall 2 End Contraction(s)
Primary OutFlow Max=5.94 cfs @ 12.07 hrs HW=4,019.15' (Free Discharge)
1=Culvert (Barrel Controls 4.77 cfs @ 3.94 fps)
2=Orifice (Orifice Controls 1.17 cfs @ 4.67 fps)
3=Weir ( Controls 0.00 cfs)
4=Top of Wall ( Controls 0.00 cfs)
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Pond 330XLHD: Cultec detention system - Chamber Wizard Field A
Chamber Model = Cultec R-330XLHD (Cultec Recharger® 330XLHD)
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
52.0" Wide + 6.0" Spacing = 58.0" C-C Row Spacing
15 Chambers/Row x 7.00' Long +1.50' Row Adjustment = 106.50' Row Length +12.0" End Stone x 2 =
108.50' Base Length
4 Rows x 52.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 20.83' Base Width
6.0" Base + 30.5" Chamber Height + 6.0" Cover = 3.54' Field Height
60 Chambers x 52.2 cf +1.50' Row Adjustment x 7.45 sf x 4 Rows = 3,174.1 cf Chamber Storage
8,005.6 cf Field - 3,174.1 cf Chambers = 4,831.5 cf Stone x 40.0% Voids = 1,932.6 cf Stone Storage
Chamber Storage + Stone Storage = 5,106.7 cf = 0.117 af
Overall Storage Efficiency = 63.8%
Overall System Size = 108.50' x 20.83' x 3.54'
60 Chambers
296.5 cy Field
178.9 cy Stone
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Type III 24-hr 25-yr Rainfall=9.68"Highlands Postconstruction wChambers
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Page 63HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Pond 330XLHD: Cultec detention system
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)9
8
7
6
5
4
3
2
1
0
Inflow Area=31,965 sf
Peak Elev=4,019.15'
Storage=1,744 cf
8.05 cfs
5.95 cfs
100
Type III 24-hr 25-yr Rainfall=9.68"Highlands Postconstruction wChambers
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Summary for Link POST: Postconstruction Site Discharge
Inflow Area = 168,784 sf, 27.75% Impervious, Inflow Depth = 4.71" for 25-yr event
Inflow = 20.16 cfs @ 12.04 hrs, Volume= 66,275 cf
Primary = 20.16 cfs @ 12.04 hrs, Volume= 66,275 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link POST: Postconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=168,784 sf
20.16 cfs20.16 cfs
101

POSTCONSTRUCTION SITE CALCULATIONS
50-YEAR STORM EVENT

102
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Summary for Subcatchment 1S: Roof
Runoff = 2.72 cfs @ 12.02 hrs, Volume= 8,307 cf, Depth=10.66"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 9,352 98
9,352 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.5 70 0.0417 2.31 Sheet Flow,
Smooth surfaces n= 0.011 P2= 5.79"
0.5 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 1S: Roof
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=9,352 sf
Runoff Volume=8,307 cf
Runoff Depth=10.66"
Flow Length=70'
Slope=0.0417 '/'
Tc=1.2 min
CN=98
2.72 cfs
103
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Summary for Subcatchment 2EX: Offsite
Runoff = 6.46 cfs @ 12.04 hrs, Volume= 18,786 cf, Depth= 3.16"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)7
6
5
4
3
2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=71,247 sf
Runoff Volume=18,786 cf
Runoff Depth=3.16"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
6.46 cfs
104
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Summary for Subcatchment 2S: Delivery/Dumpster Area
Runoff = 0.97 cfs @ 12.02 hrs, Volume= 2,964 cf, Depth=10.66"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 3,337 98
3,337 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.8 124 0.0150 2.49 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.8 124 Total, Increased to minimum Tc = 1.2 min
Subcatchment 2S: Delivery/Dumpster Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=3,337 sf
Runoff Volume=2,964 cf
Runoff Depth=10.66"
Flow Length=124'
Slope=0.0150 '/'
Tc=1.2 min
CN=98
0.97 cfs
105
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Summary for Subcatchment 3S: North Parking/Driveway
Runoff = 1.75 cfs @ 12.02 hrs, Volume= 5,340 cf, Depth=10.66"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 6,012 98
6,012 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.7 127 0.0200 2.87 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.7 127 Total, Increased to minimum Tc = 1.2 min
Subcatchment 3S: North Parking/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=6,012 sf
Runoff Volume=5,340 cf
Runoff Depth=10.66"
Flow Length=127'
Slope=0.0200 '/'
Tc=1.2 min
CN=98
1.75 cfs
106
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Summary for Subcatchment 4S: East Driveway Aisle
Runoff = 0.90 cfs @ 12.02 hrs, Volume= 2,733 cf, Depth=10.66"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 3,077 98
3,077 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 108 0.0090 1.93 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.9 108 Total, Increased to minimum Tc = 1.2 min
Subcatchment 4S: East Driveway Aisle
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=3,077 sf
Runoff Volume=2,733 cf
Runoff Depth=10.66"
Flow Length=108'
Slope=0.0090 '/'
Tc=1.2 min
CN=98
0.90 cfs
107
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Summary for Subcatchment 5S: Front Parking Area to GI2
Runoff = 1.05 cfs @ 12.02 hrs, Volume= 3,211 cf, Depth=10.66"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 3,615 98
3,615 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.4 70 0.0170 2.65 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.4 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 5S: Front Parking Area to GI2
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=3,615 sf
Runoff Volume=3,211 cf
Runoff Depth=10.66"
Flow Length=70'
Slope=0.0170 '/'
Tc=1.2 min
CN=98
1.05 cfs
108
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Summary for Subcatchment 6S: Front Parking Area to GI1
Runoff = 1.75 cfs @ 12.03 hrs, Volume= 5,019 cf, Depth= 9.16"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 2,000 60 Avg. of Woods/grass & Newly graded, HSG A
* 4,572 98
6,572 86 Weighted Average
2,000 30.43% Pervious Area
4,572 69.57% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 21 0.2500 0.21 Sheet Flow,
Grass: Bermuda n= 0.410 P2= 5.79"
0.5 51 0.0080 1.82 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
2.2 72 Total
Subcatchment 6S: Front Parking Area to GI1
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=6,572 sf
Runoff Volume=5,019 cf
Runoff Depth=9.16"
Flow Length=72'
Tc=2.2 min
CN=86
1.75 cfs
109
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Summary for Subcatchment 7S: Septic Area
Runoff = 2.00 cfs @ 12.02 hrs, Volume= 5,531 cf, Depth= 3.46"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 2,401 60 Avg. of Woods/Grass & Newly graded, HSG A
16,794 43 Woods/grass comb., Fair, HSG A
19,195 45 Weighted Average
19,195 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 230 0.0730 4.05 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
0.9 230 Total, Increased to minimum Tc = 1.2 min
Subcatchment 7S: Septic Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=19,195 sf
Runoff Volume=5,531 cf
Runoff Depth=3.46"
Flow Length=230'
Slope=0.0730 '/'
Tc=1.2 min
CN=45
2.00 cfs
110
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Page 73HydroCAD® 10.00-24 s/n 05474 © 2018 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: NW Wetland Area
Runoff = 2.75 cfs @ 12.05 hrs, Volume= 7,642 cf, Depth= 5.64"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 778 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 2,022 83 Avg. of Woods/Grass & Newly Graded, HSG C
8,086 43 Woods/grass comb., Fair, HSG A
5,379 76 Woods/grass comb., Fair, HSG C
16,265 60 Weighted Average
16,265 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
3.0 226 0.0070 1.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 8S: NW Wetland Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=16,265 sf
Runoff Volume=7,642 cf
Runoff Depth=5.64"
Flow Length=226'
Slope=0.0070 '/'
Tc=3.0 min
CN=60
2.75 cfs
111
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Summary for Subcatchment 9S: Cherrywood Dr/Driveway
Runoff = 4.60 cfs @ 12.03 hrs, Volume= 12,813 cf, Depth= 8.52"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 2,293 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,911 83 Avg. of Woods/Grass & Newly Graded, HSG C
* 4,578 98
6,273 76 Woods/grass comb., Fair, HSG C
18,055 81 Weighted Average
13,477 74.64% Pervious Area
4,578 25.36% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.0 256 0.0200 2.12 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 9S: Cherrywood Dr/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)5
4
3
2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=18,055 sf
Runoff Volume=12,813 cf
Runoff Depth=8.52"
Flow Length=256'
Slope=0.0200 '/'
Tc=2.0 min
CN=81
4.60 cfs
112
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Summary for Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff = 2.57 cfs @ 12.03 hrs, Volume= 6,934 cf, Depth= 6.90"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 50-yr Rainfall=10.90"
Area (sf) CN Description
* 5,016 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,208 98
2,833 43 Woods/grass comb., Fair, HSG A
12,057 69 Weighted Average
7,849 65.10% Pervious Area
4,208 34.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 383 0.0430 3.11 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
50-yr Rainfall=10.90"
Runoff Area=12,057 sf
Runoff Volume=6,934 cf
Runoff Depth=6.90"
Flow Length=383'
Slope=0.0430 '/'
Tc=2.1 min
CN=69
2.57 cfs
113
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Summary for Pond 330XLHD: Cultec detention system
Inflow Area = 31,965 sf, 93.74% Impervious, Inflow Depth = 10.35" for 50-yr event
Inflow = 9.09 cfs @ 12.02 hrs, Volume= 27,574 cf
Outflow = 6.72 cfs @ 12.07 hrs, Volume= 27,574 cf, Atten= 26%, Lag= 3.1 min
Primary = 6.72 cfs @ 12.07 hrs, Volume= 27,574 cf
Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Peak Elev= 4,019.27' @ 12.07 hrs Surf.Area= 2,522 sf Storage= 1,994 cf
Plug-Flow detention time= 4.4 min calculated for 27,565 cf (100% of inflow)
Center-of-Mass det. time= 4.4 min ( 745.2 - 740.8 )
Volume Invert Avail.Storage Storage Description
#1A 4,018.00' 1,933 cf 20.83'W x 108.50'L x 3.54'H Field A
8,006 cf Overall - 3,174 cf Embedded = 4,832 cf x 40.0% Voids
#2A 4,018.50' 3,174 cf Cultec R-330XLHD x 60 Inside #1
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
#3 4,018.00' 16 cf 18.0" Round 9 L.F. 18" HDPE
L= 9.0' S= 0.0050 '/'
#4 4,018.50' 9 cf 18.0" Round 5 L.F. 18" HDPE
L= 5.0' S= 0.0100 '/'
#5 4,018.55' 81 cf 4.00'D x 6.42'H JB1
#6 4,018.65' 92 cf 18.0" Round 52 L.F. 18" HDPE
L= 52.0' S= 0.0100 '/'
#7 4,018.65' 41 cf 18.0" Round 23 L.F. 18" HDPE
L= 23.0' S= 0.0100 '/'
#8 4,018.92' 58 cf 4.00'D x 4.65'H JB2
#9 4,019.02' 62 cf 18.0" Round 35 L.F. 18" HDPE
L= 35.0' S= 0.0100 '/'
#10 4,019.21' 70 cf 4.00'D x 5.57'H GI2
#11 4,019.31' 138 cf 18.0" Round 78 L.F. 18" HDPE
L= 78.0' S= 0.0100 '/'
#12 4,019.41' 59 cf 4.00'D x 4.70'H GI6
#13 4,019.51' 131 cf 18.0" Round 74 L.F. 18" HDPE
L= 74.0' S= 0.0100 '/'
#14 4,020.13' 58 cf 4.00'D x 4.63'H GI1
#15 4,020.29' 39 cf 4.00'D x 3.08'H GI5
#16 4,018.55' 65 cf 4.00'D x 5.21'H GI4
#17 4,018.65' 97 cf 18.0" Round 55 L.F. 18" HDPE
L= 55.0' S= 0.0100 '/'
#18 4,019.24' 63 cf 4.00'D x 5.00'H GI3
6,185 cf Total Available Storage
Storage Group A created with Chamber Wizard
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Device Routing Invert Outlet Devices
#1 Primary 4,017.85'18.0" Round Culvert L= 14.0' Ke= 0.500
Inlet / Outlet Invert= 4,017.85' / 4,017.77' S= 0.0057 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Primary 4,017.95'6.0" W x 6.0" H Vert. Orifice C= 0.600
#3 Primary 4,020.50'1.5' long Weir 2 End Contraction(s) 1.0' Crest Height
#4 Primary 4,021.50'5.0' long Top of Wall 2 End Contraction(s)
Primary OutFlow Max=6.72 cfs @ 12.07 hrs HW=4,019.27' (Free Discharge)
1=Culvert (Barrel Controls 5.48 cfs @ 4.09 fps)
2=Orifice (Orifice Controls 1.24 cfs @ 4.96 fps)
3=Weir ( Controls 0.00 cfs)
4=Top of Wall ( Controls 0.00 cfs)
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Pond 330XLHD: Cultec detention system - Chamber Wizard Field A
Chamber Model = Cultec R-330XLHD (Cultec Recharger® 330XLHD)
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
52.0" Wide + 6.0" Spacing = 58.0" C-C Row Spacing
15 Chambers/Row x 7.00' Long +1.50' Row Adjustment = 106.50' Row Length +12.0" End Stone x 2 =
108.50' Base Length
4 Rows x 52.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 20.83' Base Width
6.0" Base + 30.5" Chamber Height + 6.0" Cover = 3.54' Field Height
60 Chambers x 52.2 cf +1.50' Row Adjustment x 7.45 sf x 4 Rows = 3,174.1 cf Chamber Storage
8,005.6 cf Field - 3,174.1 cf Chambers = 4,831.5 cf Stone x 40.0% Voids = 1,932.6 cf Stone Storage
Chamber Storage + Stone Storage = 5,106.7 cf = 0.117 af
Overall Storage Efficiency = 63.8%
Overall System Size = 108.50' x 20.83' x 3.54'
60 Chambers
296.5 cy Field
178.9 cy Stone
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Pond 330XLHD: Cultec detention system
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)10
9
8
7
6
5
4
3
2
1
0
Inflow Area=31,965 sf
Peak Elev=4,019.27'
Storage=1,994 cf
9.09 cfs
6.72 cfs
117
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Summary for Link POST: Postconstruction Site Discharge
Inflow Area = 168,784 sf, 27.75% Impervious, Inflow Depth = 5.64" for 50-yr event
Inflow = 24.53 cfs @ 12.04 hrs, Volume= 79,279 cf
Primary = 24.53 cfs @ 12.04 hrs, Volume= 79,279 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link POST: Postconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=168,784 sf
24.53 cfs24.53 cfs
118

POSTCONSTRUCTION SITE CALCULATIONS
100-YEAR STORM EVENT

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Summary for Subcatchment 1S: Roof
Runoff = 3.02 cfs @ 12.02 hrs, Volume= 9,242 cf, Depth=11.86"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 9,352 98
9,352 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.5 70 0.0417 2.31 Sheet Flow,
Smooth surfaces n= 0.011 P2= 5.79"
0.5 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 1S: Roof
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=9,352 sf
Runoff Volume=9,242 cf
Runoff Depth=11.86"
Flow Length=70'
Slope=0.0417 '/'
Tc=1.2 min
CN=98
3.02 cfs
120
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Summary for Subcatchment 2EX: Offsite
Runoff = 8.23 cfs @ 12.04 hrs, Volume= 23,347 cf, Depth= 3.93"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 8,084 98 road
63,163 36 Woods, Fair, HSG A
71,247 43 Weighted Average
63,163 88.65% Pervious Area
8,084 11.35% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 200 0.1000 1.58 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2EX: Offsite
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)9
8
7
6
5
4
3
2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=71,247 sf
Runoff Volume=23,347 cf
Runoff Depth=3.93"
Flow Length=200'
Slope=0.1000 '/'
Tc=2.1 min
CN=43
8.23 cfs
121
Type III 24-hr 100-yr Rainfall=12.10"Highlands Postconstruction wChambers
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Summary for Subcatchment 2S: Delivery/Dumpster Area
Runoff = 1.08 cfs @ 12.02 hrs, Volume= 3,298 cf, Depth=11.86"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 3,337 98
3,337 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.8 124 0.0150 2.49 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.8 124 Total, Increased to minimum Tc = 1.2 min
Subcatchment 2S: Delivery/Dumpster Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=3,337 sf
Runoff Volume=3,298 cf
Runoff Depth=11.86"
Flow Length=124'
Slope=0.0150 '/'
Tc=1.2 min
CN=98
1.08 cfs
122
Type III 24-hr 100-yr Rainfall=12.10"Highlands Postconstruction wChambers
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Summary for Subcatchment 3S: North Parking/Driveway
Runoff = 1.94 cfs @ 12.02 hrs, Volume= 5,941 cf, Depth=11.86"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 6,012 98
6,012 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.7 127 0.0200 2.87 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.7 127 Total, Increased to minimum Tc = 1.2 min
Subcatchment 3S: North Parking/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=6,012 sf
Runoff Volume=5,941 cf
Runoff Depth=11.86"
Flow Length=127'
Slope=0.0200 '/'
Tc=1.2 min
CN=98
1.94 cfs
123
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Summary for Subcatchment 4S: East Driveway Aisle
Runoff = 1.00 cfs @ 12.02 hrs, Volume= 3,041 cf, Depth=11.86"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 3,077 98
3,077 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 108 0.0090 1.93 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.9 108 Total, Increased to minimum Tc = 1.2 min
Subcatchment 4S: East Driveway Aisle
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=3,077 sf
Runoff Volume=3,041 cf
Runoff Depth=11.86"
Flow Length=108'
Slope=0.0090 '/'
Tc=1.2 min
CN=98
1.00 cfs
124
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Summary for Subcatchment 5S: Front Parking Area to GI2
Runoff = 1.17 cfs @ 12.02 hrs, Volume= 3,572 cf, Depth=11.86"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 3,615 98
3,615 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.4 70 0.0170 2.65 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
0.4 70 Total, Increased to minimum Tc = 1.2 min
Subcatchment 5S: Front Parking Area to GI2
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=3,615 sf
Runoff Volume=3,572 cf
Runoff Depth=11.86"
Flow Length=70'
Slope=0.0170 '/'
Tc=1.2 min
CN=98
1.17 cfs
125
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Summary for Subcatchment 6S: Front Parking Area to GI1
Runoff = 1.96 cfs @ 12.03 hrs, Volume= 5,665 cf, Depth=10.34"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 2,000 60 Avg. of Woods/grass & Newly graded, HSG A
* 4,572 98
6,572 86 Weighted Average
2,000 30.43% Pervious Area
4,572 69.57% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 21 0.2500 0.21 Sheet Flow,
Grass: Bermuda n= 0.410 P2= 5.79"
0.5 51 0.0080 1.82 Shallow Concentrated Flow,
Paved Kv= 20.3 fps
2.2 72 Total
Subcatchment 6S: Front Parking Area to GI1
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=6,572 sf
Runoff Volume=5,665 cf
Runoff Depth=10.34"
Flow Length=72'
Tc=2.2 min
CN=86
1.96 cfs
126
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Summary for Subcatchment 7S: Septic Area
Runoff = 2.52 cfs @ 12.02 hrs, Volume= 6,816 cf, Depth= 4.26"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 2,401 60 Avg. of Woods/Grass & Newly graded, HSG A
16,794 43 Woods/grass comb., Fair, HSG A
19,195 45 Weighted Average
19,195 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
0.9 230 0.0730 4.05 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
0.9 230 Total, Increased to minimum Tc = 1.2 min
Subcatchment 7S: Septic Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=19,195 sf
Runoff Volume=6,816 cf
Runoff Depth=4.26"
Flow Length=230'
Slope=0.0730 '/'
Tc=1.2 min
CN=45
2.52 cfs
127
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Summary for Subcatchment 8S: NW Wetland Area
Runoff = 3.25 cfs @ 12.05 hrs, Volume= 9,013 cf, Depth= 6.65"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 778 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 2,022 83 Avg. of Woods/Grass & Newly Graded, HSG C
8,086 43 Woods/grass comb., Fair, HSG A
5,379 76 Woods/grass comb., Fair, HSG C
16,265 60 Weighted Average
16,265 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
3.0 226 0.0070 1.25 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 8S: NW Wetland Area
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=16,265 sf
Runoff Volume=9,013 cf
Runoff Depth=6.65"
Flow Length=226'
Slope=0.0070 '/'
Tc=3.0 min
CN=60
3.25 cfs
128
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Summary for Subcatchment 9S: Cherrywood Dr/Driveway
Runoff = 5.19 cfs @ 12.03 hrs, Volume= 14,563 cf, Depth= 9.68"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 2,293 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,911 83 Avg. of Woods/Grass & Newly Graded, HSG C
* 4,578 98
6,273 76 Woods/grass comb., Fair, HSG C
18,055 81 Weighted Average
13,477 74.64% Pervious Area
4,578 25.36% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.0 256 0.0200 2.12 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 9S: Cherrywood Dr/Driveway
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)5
4
3
2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=18,055 sf
Runoff Volume=14,563 cf
Runoff Depth=9.68"
Flow Length=256'
Slope=0.0200 '/'
Tc=2.0 min
CN=81
5.19 cfs
129
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Summary for Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff = 2.96 cfs @ 12.03 hrs, Volume= 8,033 cf, Depth= 7.99"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Type III 24-hr 100-yr Rainfall=12.10"
Area (sf) CN Description
* 5,016 60 Avg. of Woods/Grass & Newly Graded, HSG A
* 4,208 98
2,833 43 Woods/grass comb., Fair, HSG A
12,057 69 Weighted Average
7,849 65.10% Pervious Area
4,208 34.90% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
2.1 383 0.0430 3.11 Shallow Concentrated Flow,
Grassed Waterway Kv= 15.0 fps
Subcatchment 10S: Cashiers Rd. R.O.W.
Runoff
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)3
2
1
0
Type III 24-hr
100-yr Rainfall=12.10"
Runoff Area=12,057 sf
Runoff Volume=8,033 cf
Runoff Depth=7.99"
Flow Length=383'
Slope=0.0430 '/'
Tc=2.1 min
CN=69
2.96 cfs
130
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Summary for Pond 330XLHD: Cultec detention system
Inflow Area = 31,965 sf, 93.74% Impervious, Inflow Depth = 11.55" for 100-yr event
Inflow = 10.11 cfs @ 12.02 hrs, Volume= 30,759 cf
Outflow = 7.46 cfs @ 12.07 hrs, Volume= 30,759 cf, Atten= 26%, Lag= 3.1 min
Primary = 7.46 cfs @ 12.07 hrs, Volume= 30,759 cf
Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Peak Elev= 4,019.39' @ 12.07 hrs Surf.Area= 2,553 sf Storage= 2,241 cf
Plug-Flow detention time= 4.4 min calculated for 30,759 cf (100% of inflow)
Center-of-Mass det. time= 4.4 min ( 743.9 - 739.5 )
Volume Invert Avail.Storage Storage Description
#1A 4,018.00' 1,933 cf 20.83'W x 108.50'L x 3.54'H Field A
8,006 cf Overall - 3,174 cf Embedded = 4,832 cf x 40.0% Voids
#2A 4,018.50' 3,174 cf Cultec R-330XLHD x 60 Inside #1
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
#3 4,018.00' 16 cf 18.0" Round 9 L.F. 18" HDPE
L= 9.0' S= 0.0050 '/'
#4 4,018.50' 9 cf 18.0" Round 5 L.F. 18" HDPE
L= 5.0' S= 0.0100 '/'
#5 4,018.55' 81 cf 4.00'D x 6.42'H JB1
#6 4,018.65' 92 cf 18.0" Round 52 L.F. 18" HDPE
L= 52.0' S= 0.0100 '/'
#7 4,018.65' 41 cf 18.0" Round 23 L.F. 18" HDPE
L= 23.0' S= 0.0100 '/'
#8 4,018.92' 58 cf 4.00'D x 4.65'H JB2
#9 4,019.02' 62 cf 18.0" Round 35 L.F. 18" HDPE
L= 35.0' S= 0.0100 '/'
#10 4,019.21' 70 cf 4.00'D x 5.57'H GI2
#11 4,019.31' 138 cf 18.0" Round 78 L.F. 18" HDPE
L= 78.0' S= 0.0100 '/'
#12 4,019.41' 59 cf 4.00'D x 4.70'H GI6
#13 4,019.51' 131 cf 18.0" Round 74 L.F. 18" HDPE
L= 74.0' S= 0.0100 '/'
#14 4,020.13' 58 cf 4.00'D x 4.63'H GI1
#15 4,020.29' 39 cf 4.00'D x 3.08'H GI5
#16 4,018.55' 65 cf 4.00'D x 5.21'H GI4
#17 4,018.65' 97 cf 18.0" Round 55 L.F. 18" HDPE
L= 55.0' S= 0.0100 '/'
#18 4,019.24' 63 cf 4.00'D x 5.00'H GI3
6,185 cf Total Available Storage
Storage Group A created with Chamber Wizard
131
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Device Routing Invert Outlet Devices
#1 Primary 4,017.85'18.0" Round Culvert L= 14.0' Ke= 0.500
Inlet / Outlet Invert= 4,017.85' / 4,017.77' S= 0.0057 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Primary 4,017.95'6.0" W x 6.0" H Vert. Orifice C= 0.600
#3 Primary 4,020.50'1.5' long Weir 2 End Contraction(s) 1.0' Crest Height
#4 Primary 4,021.50'5.0' long Top of Wall 2 End Contraction(s)
Primary OutFlow Max=7.46 cfs @ 12.07 hrs HW=4,019.38' (Free Discharge)
1=Culvert (Barrel Controls 6.15 cfs @ 4.23 fps)
2=Orifice (Orifice Controls 1.31 cfs @ 5.23 fps)
3=Weir ( Controls 0.00 cfs)
4=Top of Wall ( Controls 0.00 cfs)
132
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Pond 330XLHD: Cultec detention system - Chamber Wizard Field A
Chamber Model = Cultec R-330XLHD (Cultec Recharger® 330XLHD)
Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.00'L = 52.2 cf
Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap
Row Length Adjustment= +1.50' x 7.45 sf x 4 rows
52.0" Wide + 6.0" Spacing = 58.0" C-C Row Spacing
15 Chambers/Row x 7.00' Long +1.50' Row Adjustment = 106.50' Row Length +12.0" End Stone x 2 =
108.50' Base Length
4 Rows x 52.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 20.83' Base Width
6.0" Base + 30.5" Chamber Height + 6.0" Cover = 3.54' Field Height
60 Chambers x 52.2 cf +1.50' Row Adjustment x 7.45 sf x 4 Rows = 3,174.1 cf Chamber Storage
8,005.6 cf Field - 3,174.1 cf Chambers = 4,831.5 cf Stone x 40.0% Voids = 1,932.6 cf Stone Storage
Chamber Storage + Stone Storage = 5,106.7 cf = 0.117 af
Overall Storage Efficiency = 63.8%
Overall System Size = 108.50' x 20.83' x 3.54'
60 Chambers
296.5 cy Field
178.9 cy Stone
133
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Pond 330XLHD: Cultec detention system
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=31,965 sf
Peak Elev=4,019.39'
Storage=2,241 cf
10.11 cfs
7.46 cfs
134
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Summary for Link POST: Postconstruction Site Discharge
Inflow Area = 168,784 sf, 27.75% Impervious, Inflow Depth = 6.58" for 100-yr event
Inflow = 28.96 cfs @ 12.04 hrs, Volume= 92,530 cf
Primary = 28.96 cfs @ 12.04 hrs, Volume= 92,530 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs
Link POST: Postconstruction Site Discharge
Inflow
Primary
Hydrograph
Time (hours)
3029282726252423222120191817161514131211109876543210Flow (cfs)32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=168,784 sf
28.96 cfs28.96 cfs
135

APPENDIX C
NRCS SOIL REPORT
136
Hydrologic Soil Group—Macon County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/28/2019
Page 1 of 438847803884810388484038848703884900388493038849603884780388481038848403884870388490038849303884960301610301640301670301700301730301760301790301820301850301880301910
301610 301640 301670 301700 301730 301760 301790 301820 301850 301880 301910
35° 5' 17'' N 83° 10' 34'' W35° 5' 17'' N83° 10' 22'' W35° 5' 10'' N
83° 10' 34'' W35° 5' 10'' N
83° 10' 22'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,480 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
137
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:12,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Macon County, North Carolina
Survey Area Data: Version 15, Sep 11, 2018
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Feb 6, 2016—Oct 26,
2017
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—Macon County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/28/2019
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Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
CuD Cullasaja-Tuckasegee
complex, 15 to 30
percent slopes, stony
A 2.3 58.3%
EdC Edneyville-Chestnut
complex, 8 to 15
percent slopes, stony
A 0.0 0.2%
Ud Udorthents, loamy C 1.6 41.5%
Totals for Area of Interest 3.9 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Hydrologic Soil Group—Macon County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/28/2019
Page 3 of 4
139
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Macon County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/28/2019
Page 4 of 4
140