Poplin Meadows - Poplin Meadows -Stormwater Report - 180802

BOHLER ENGINEERING 1927 S TRYON ST. ♦ SUITE 310 ♦ CHARLOTTE, NC 28203 ♦ 980.272.3400

STORMWATER MANAGEMENT REPORT
PREPARED FOR:

LIQUID MANAGEMENT, LLC
BONTERRA VILLAGE WAY
INDIAN TRAIL, NC
UNION COUNTY
BEPC #NCC172107

August 2, 2018

PREPARED BY:
BOHLER ENGINEERING, NC, PLLC
1927 S. TYRON ST. SUITE 310
CHARLOTTE, NC 28203
[phone]

__ ________________________________
NORTH CAROLINA LICENSE #043610
MICHAEL THEBERGE, P.E.

PROFESSIONAL CERTIFICATION: I HEREBY CERTIFY THAT THESE DOCUMENTS WERE PREPARED OR APPROVED BY ME, AND
THAT I AM A DULY LICENSED REGISTERED ENGINEER UNDER THE LAWS OF THE STATE OF NORTH CAROLINA

CIVIL & CONSULTING ENGINEERS▪SURVEYORS▪TRAFFIC CONSULTANTS
www.bohlereng.com

2

Table of Contents

General Project Description ................................................................................................................. 3

Stormwater Management Analysis and BMP Calculations .................................................................. 4

Appendix ............................................................................................................................................... 6
HydroCAD Output ..........................................................................................................................
Stormsewer Output .......................................................................................................................

3

General Project Description/Stormwater Management

GENERAL PROJECT OVERVIEW AND EXISTING CONDITIONS

The subject site is located along Bonterra Village Way, in Union County. The project site is
currently vacant and consists of approximately 11.48 acres and will include approximately 99
single family lots. There is an existing intermittent stream following the southwest side of the
property line

The site is majority pasture with some wooded areas, with average existing slopes of 3% to
5%. There is currently no stormwater measure provided on the site. Located on the southend
of the property is an existing ditch that takes water from the property and directs it thru the
existing stream offsite. There is no off-site area examined in this analysis.

STORMWATER REQUIREMENTS AND DESIGN OVERVIEW

This project is located in the Eastern Catawba district and is adjacent to North Fork Crooked
Creek. This project is classified as a high-density project because each drainage area has
greater than 12% built upon area.

Stormwater quality treatment systems shall treat the runoff generated from the first inch of
rainfall.

All structural stormwater treatment systems used to meet these requirements shall be designed
to have a minimum of 85% average annual removal for total suspended solids and 70%
average annual removal for total phosphorus.

General engineering design criteria shall be accordance with 15 A NCAC 2H. 1008(c) in the
design manual.

The peak discharge is attenuated for both the 2-year, 24-hr storm and the 25-year, 24-hr storm
events. The 100-year, 24-hr storm event has been analyzed to provide 1’ of freeboard to the
top of berm.

Areas not controlled by systems due to topographic challenges are sheet flowing through the
vegetated buffer, but all proposed impervious areas are treated within the proposed stormwater
control measures.

Please note that all runoff from the roofs of the homes is to be routed to underground storm
drains that discharge into the wet detention pond. Some homes will have direct tie-ins of their
roof drains to nearby structures and some will flow overland and in channels to nearby inlets.

STORMSEWER DESIGN

Stormwater run-off from the site will be directed to the existing outfall locations via a system of
storm sewer pipes. The storm sewer was modeled in Hydraflow Storm Sewers Extension for

4

Autodesk AutoCAD Civil 3D. The storm sewer pipes were modeled to ensure their adequate
capacity with a minimum slope of 0.5% to promote flushing of the pipes.

Stormwater Management and BMP Calculations

PRE VS. POST ANALYSIS PEAK ATTENUATION

See table below for final flow calculations for the pre and post conditions. It should be noted
that time of concentration is accounted for in the summation of the combined peak discharge
values.

DRAINAGE AREA
2-YR 24
HR(cfs)
25-YR 24
HR(cfs)
POI 1 COMBINED:
PRE DA 1 15.75 38.01
POST DA 1 9.64 35.39
POI 2:
PRE DA 2 4.40 10.73
POST DA 2 1.98 4.85

All associated calculations have been provided within the Appendix section of this report.

WATER QUALITY

Water quality treatment of the 1” water quality volume, is also provided within the proposed
above-ground wet detention pond, and is to be detained between 2-5days (See appendix for
calculations).

5

Appendix
DESIGN:
GIVEN:
7.63 Ac.
65%
3 FEET
65%
SA/DA = 2.30 % = 0.0230 Updated MDC
SA REQUIRED = 7.63 Ac. X 0.0230
= 0.18 Ac.
= 7,642 SF
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
Design Rainfall = 1 Inch
Drainage Area = 7.63 Acres
Rv = 0.05 + 0.9(I)
I = Percent Impervious = 65%
Rv = 0.64 in./in.
V1 =0.404 acre-feet = 17,607
ft3
Pond Height above Orifice = 625.41 feet
Orifice Invert Elevation = 623.50 feet
Orifice Diameter (D) = 2.00 inches = 0.17 feet
Orifice Area (a) = 0.0218 square feet
Gravitational Constant (g) = 32.2 ft/sec2
Head (H) = 1.83 feet
Driving Head (HO) =0.609 feet
Discharge Coefficient (CD) =0.6
Drawdown rate (Q) = 0.082 cfs
Time (t) = 214,806 seconds = 2.49 days
Note:
The above calculation is based on the orifice equation where:
3) Pond Drawdown Time
ALLOCATED AS A PERMANENT POOL
V1 = (Design Rainfall)(Rv)(Drainage Area)
WET POND #1 Poplin (Union county)
WATER QUALITY TO MEET 85% TSS REMOVAL
Self-Storage FacilityLAND USE =
ESTIMATED PERCENT IMPERVIOUS =
DRAINAGE AREA TO FACILITY =
AVERAGE POOL DEPTH =
1) SA/DA RATIO:
PROVIDE VOLUME TO DETAIN THE 1" STORM EVENT ABOVE THE ELEVATION
PERCENT IMPERVIOUS =
2) TEMPORARY WATER QUALITY POOL REQUIREMENTS
8/2/2018 11:50 AM Page 1 of 1
8/2/2018 1:58 PM Page 1 of 1
1S
Pre DA 1
2S
Pre DA 2
4S
Post DA 1 Controlled
7S
Post DA 1 Sheet Flow
8S
Post DA 2
5P
Pond 1
6L
POI 1 Combined
Routing Diagram for NCC172107 - Poplin Road - 180731
Prepared by Bohler Engineering, Printed 8/2/2018
HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 2HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Area Listing (selected nodes)
Area
(acres)
CN Description
(subcatchment-numbers)
3.430 61 >75% Grass cover, Good, HSG B (4S, 7S)
1.500 80 >75% Grass cover, Good, HSG D (7S)
7.150 80 Pasture/grassland/range, Good, HSG D (1S, 2S)
4.560 98 Paved roads w/curbs & sewers, HSG B (4S)
6.850 77 Woods, Good, HSG D (1S, 2S, 7S, 8S)
23.490 80 TOTAL AREA
NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 3HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Soil Listing (selected nodes)
Area
(acres)
Soil
Group
Subcatchment
Numbers
0.000 HSG A
7.990 HSG B 4S, 7S
0.000 HSG C
15.500 HSG D 1S, 2S, 7S, 8S
0.000 Other
23.490 TOTAL AREA
NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 5HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Pipe Listing (selected nodes)
Line# Node
Number
In-Invert
(feet)
Out-Invert
(feet)
Length
(feet)
Slope
(ft/ft)
n Diam/Width
(inches)
Height
(inches)
Inside-Fill
(inches)
1 5P 623.50 623.00 75.0 0.0067 0.011 18.0 0.0 0.0
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 6HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-60.00 hrs, dt=0.05 hrs, 1201 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Runoff Area=9.550 ac 0.00% Impervious Runoff Depth=1.60"Subcatchment 1S: Pre DA 1
Flow Length=1,778' Tc=22.4 min CN=79 Runoff=15.75 cfs 1.277 af
Runoff Area=2.200 ac 0.00% Impervious Runoff Depth=1.54"Subcatchment 2S: Pre DA 2
Flow Length=1,220' Tc=14.4 min CN=78 Runoff=4.40 cfs 0.282 af
Runoff Area=7.620 ac 59.84% Impervious Runoff Depth=1.90"Subcatchment 4S: Post DA 1 Controlled
Tc=5.0 min CN=83 Runoff=25.95 cfs 1.207 af
Runoff Area=3.370 ac 0.00% Impervious Runoff Depth=1.47"Subcatchment 7S: Post DA 1 Sheet Flow
Tc=10.0 min CN=77 Runoff=7.46 cfs 0.412 af
Runoff Area=0.750 ac 0.00% Impervious Runoff Depth=1.47"Subcatchment 8S: Post DA 2
Flow Length=260' Slope=0.0300 '/' Tc=5.0 min CN=77 Runoff=1.98 cfs 0.092 af
Peak Elev=625.91' Storage=25,327 cf Inflow=25.95 cfs 1.207 afPond 5P: Pond 1
Primary=3.64 cfs 1.122 af Secondary=0.00 cfs 0.000 af Outflow=3.64 cfs 1.122 af
Inflow=9.64 cfs 1.534 afLink 6L: POI 1 Combined
Primary=9.64 cfs 1.534 af
Total Runoff Area = 23.490 ac Runoff Volume = 3.270 af Average Runoff Depth = 1.67"
80.59% Pervious = 18.930 ac 19.41% Impervious = 4.560 ac
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 7HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1
Runoff = 15.75 cfs @ 12.16 hrs, Volume= 1.277 af, Depth= 1.60"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.55"
Area (ac) CN Description
6.450 80 Pasture/grassland/range, Good, HSG D
3.100 77 Woods, Good, HSG D
9.550 79 Weighted Average
9.550 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
11.5 150 0.0200 0.22 Sheet Flow,
Range n= 0.130 P2= 3.55"
3.4 200 0.0200 0.99 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
7.5 1,428 0.0110 3.17 9.50 Channel Flow,
Area= 3.0 sf Perim= 5.0' r= 0.60'
n= 0.035 Earth, dense weeds
22.4 1,778 Total
Subcatchment 1S: Pre DA 1
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
2-Year Rainfall=3.55"
Runoff Area=9.550 ac
Runoff Volume=1.277 af
Runoff Depth=1.60"
Flow Length=1,778'
Tc=22.4 min
CN=79
15.75 cfs
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 9HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 2
Runoff = 4.40 cfs @ 12.07 hrs, Volume= 0.282 af, Depth= 1.54"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.55"
Area (ac) CN Description
1.500 77 Woods, Good, HSG D
0.700 80 Pasture/grassland/range, Good, HSG D
2.200 78 Weighted Average
2.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
6.4 100 0.0500 0.26 Sheet Flow,
Grass: Short n= 0.150 P2= 3.55"
3.0 860 0.0200 4.73 23.67 Channel Flow,
Area= 5.0 sf Perim= 9.0' r= 0.56'
n= 0.030 Earth, grassed & winding
5.0 260 0.0300 0.87 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
14.4 1,220 Total
Subcatchment 2S: Pre DA 2
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)4
3
2
1
0
Type II 24-hr
2-Year Rainfall=3.55"
Runoff Area=2.200 ac
Runoff Volume=0.282 af
Runoff Depth=1.54"
Flow Length=1,220'
Tc=14.4 min
CN=78
4.40 cfs
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 11HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Post DA 1 Controlled
[49] Hint: Tc<2dt may require smaller dt
Runoff = 25.95 cfs @ 11.96 hrs, Volume= 1.207 af, Depth= 1.90"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.55"
Area (ac) CN Description
4.560 98 Paved roads w/curbs & sewers, HSG B
3.060 61 >75% Grass cover, Good, HSG B
7.620 83 Weighted Average
3.060 40.16% Pervious Area
4.560 59.84% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 4S: Post DA 1 Controlled
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
2-Year Rainfall=3.55"
Runoff Area=7.620 ac
Runoff Volume=1.207 af
Runoff Depth=1.90"
Tc=5.0 min
CN=83
25.95 cfs
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 13HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA 1 Sheet Flow
Runoff = 7.46 cfs @ 12.02 hrs, Volume= 0.412 af, Depth= 1.47"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.55"
Area (ac) CN Description
1.500 77 Woods, Good, HSG D
1.500 80 >75% Grass cover, Good, HSG D
0.370 61 >75% Grass cover, Good, HSG B
3.370 77 Weighted Average
3.370 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 Direct Entry,
Subcatchment 7S: Post DA 1 Sheet Flow
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)8
7
6
5
4
3
2
1
0
Type II 24-hr
2-Year Rainfall=3.55"
Runoff Area=3.370 ac
Runoff Volume=0.412 af
Runoff Depth=1.47"
Tc=10.0 min
CN=77
7.46 cfs
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 15HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA 2
[49] Hint: Tc<2dt may require smaller dt
Runoff = 1.98 cfs @ 11.96 hrs, Volume= 0.092 af, Depth= 1.47"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.55"
Area (ac) CN Description
0.750 77 Woods, Good, HSG D
0.750 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 260 0.0300 0.87 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 8S: Post DA 2
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)2
1
0
Type II 24-hr
2-Year Rainfall=3.55"
Runoff Area=0.750 ac
Runoff Volume=0.092 af
Runoff Depth=1.47"
Flow Length=260'
Slope=0.0300 '/'
Tc=5.0 min
CN=77
1.98 cfs
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 17HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 5P: Pond 1
Inflow Area = 7.620 ac, 59.84% Impervious, Inflow Depth = 1.90" for 2-Year event
Inflow = 25.95 cfs @ 11.96 hrs, Volume= 1.207 af
Outflow = 3.64 cfs @ 12.21 hrs, Volume= 1.122 af, Atten= 86%, Lag= 15.0 min
Primary = 3.64 cfs @ 12.21 hrs, Volume= 1.122 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 625.91' @ 12.21 hrs Surf.Area= 12,226 sf Storage= 25,327 cf
Plug-Flow detention time= 614.0 min calculated for 1.121 af (93% of inflow)
Center-of-Mass det. time= 577.3 min ( 1,401.3 - 824.1 )
Volume Invert Avail.Storage Storage Description
#1 623.50' 78,405 cf Above Permanent Pool (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
623.50 8,755 0 0
629.50 17,380 78,405 78,405
Device Routing Invert Outlet Devices
#1 Primary 623.50'18.0" Round Culvert
L= 75.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 623.50' / 623.00' S= 0.0067 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 623.50'2.2" Vert. Orifice/Grate C= 0.600
#3 Device 1 625.41'36.0" W x 28.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 627.75'20.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 628.25'70.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=3.64 cfs @ 12.21 hrs HW=625.91' TW=0.00' (Dynamic Tailwater)
1=Culvert (Passes 3.64 cfs of 11.42 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.19 cfs @ 7.34 fps)
3=Orifice/Grate (Orifice Controls 3.45 cfs @ 2.28 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=623.50' TW=0.00' (Dynamic Tailwater)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 18HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Pond 5P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=7.620 ac
Peak Elev=625.91'
Storage=25,327 cf
25.95 cfs
3.64 cfs
3.64 cfs
0.00 cfs
Pond 5P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
250200150100500Elevation (feet)629
628
627
626
625
624 Culvert + Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 20HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Hydrograph for Pond 5P: Pond 1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 0 623.50 0.00 0.00 0.00
2.50 0.00 0 623.50 0.00 0.00 0.00
5.00 0.00 0 623.50 0.00 0.00 0.00
7.50 0.00 0 623.50 0.00 0.00 0.00
10.00 0.20 591 623.57 0.01 0.01 0.00
12.50 2.18 24,704 625.86 3.13 3.13 0.00
15.00 0.67 21,176 625.57 0.78 0.78 0.00
17.50 0.44 20,498 625.51 0.48 0.48 0.00
20.00 0.30 20,125 625.48 0.34 0.34 0.00
22.50 0.27 19,925 625.46 0.28 0.28 0.00
25.00 0.00 19,206 625.40 0.17 0.17 0.00
27.50 0.00 17,697 625.27 0.16 0.16 0.00
30.00 0.00 16,246 625.14 0.16 0.16 0.00
32.50 0.00 14,854 625.01 0.15 0.15 0.00
35.00 0.00 13,522 624.89 0.14 0.14 0.00
37.50 0.00 12,251 624.77 0.14 0.14 0.00
40.00 0.00 11,042 624.65 0.13 0.13 0.00
42.50 0.00 9,895 624.54 0.12 0.12 0.00
45.00 0.00 8,813 624.43 0.12 0.12 0.00
47.50 0.00 7,795 624.33 0.11 0.11 0.00
50.00 0.00 6,843 624.24 0.10 0.10 0.00
52.50 0.00 5,957 624.15 0.09 0.09 0.00
55.00 0.00 5,139 624.06 0.09 0.09 0.00
57.50 0.00 4,390 623.98 0.08 0.08 0.00
60.00 0.00 3,709 623.91 0.07 0.07 0.00
Type II 24-hr 2-Year Rainfall=3.55"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 23HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Link 6L: POI 1 Combined
Inflow Area = 10.990 ac, 41.49% Impervious, Inflow Depth > 1.68" for 2-Year event
Inflow = 9.64 cfs @ 12.06 hrs, Volume= 1.534 af
Primary = 9.64 cfs @ 12.06 hrs, Volume= 1.534 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Link 6L: POI 1 Combined
Inflow
Primary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)10
9
8
7
6
5
4
3
2
1
0
Inflow Area=10.990 ac
9.64 cfs
9.64 cfs
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 25HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-60.00 hrs, dt=0.05 hrs, 1201 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Runoff Area=9.550 ac 0.00% Impervious Runoff Depth=3.84"Subcatchment 1S: Pre DA 1
Flow Length=1,778' Tc=22.4 min CN=79 Runoff=38.01 cfs 3.057 af
Runoff Area=2.200 ac 0.00% Impervious Runoff Depth=3.74"Subcatchment 2S: Pre DA 2
Flow Length=1,220' Tc=14.4 min CN=78 Runoff=10.73 cfs 0.685 af
Runoff Area=7.620 ac 59.84% Impervious Runoff Depth=4.26"Subcatchment 4S: Post DA 1 Controlled
Tc=5.0 min CN=83 Runoff=56.28 cfs 2.704 af
Runoff Area=3.370 ac 0.00% Impervious Runoff Depth=3.64"Subcatchment 7S: Post DA 1 Sheet Flow
Tc=10.0 min CN=77 Runoff=18.45 cfs 1.021 af
Runoff Area=0.750 ac 0.00% Impervious Runoff Depth=3.64"Subcatchment 8S: Post DA 2
Flow Length=260' Slope=0.0300 '/' Tc=5.0 min CN=77 Runoff=4.85 cfs 0.227 af
Peak Elev=627.77' Storage=50,459 cf Inflow=56.28 cfs 2.704 afPond 5P: Pond 1
Primary=17.36 cfs 2.616 af Secondary=0.00 cfs 0.000 af Outflow=17.36 cfs 2.616 af
Inflow=35.39 cfs 3.637 afLink 6L: POI 1 Combined
Primary=35.39 cfs 3.637 af
Total Runoff Area = 23.490 ac Runoff Volume = 7.695 af Average Runoff Depth = 3.93"
80.59% Pervious = 18.930 ac 19.41% Impervious = 4.560 ac
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 26HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1
Runoff = 38.01 cfs @ 12.15 hrs, Volume= 3.057 af, Depth= 3.84"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.18"
Area (ac) CN Description
6.450 80 Pasture/grassland/range, Good, HSG D
3.100 77 Woods, Good, HSG D
9.550 79 Weighted Average
9.550 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
11.5 150 0.0200 0.22 Sheet Flow,
Range n= 0.130 P2= 3.55"
3.4 200 0.0200 0.99 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
7.5 1,428 0.0110 3.17 9.50 Channel Flow,
Area= 3.0 sf Perim= 5.0' r= 0.60'
n= 0.035 Earth, dense weeds
22.4 1,778 Total
Subcatchment 1S: Pre DA 1
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
25-Year Rainfall=6.18"
Runoff Area=9.550 ac
Runoff Volume=3.057 af
Runoff Depth=3.84"
Flow Length=1,778'
Tc=22.4 min
CN=79
38.01 cfs
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 28HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 2
Runoff = 10.73 cfs @ 12.06 hrs, Volume= 0.685 af, Depth= 3.74"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.18"
Area (ac) CN Description
1.500 77 Woods, Good, HSG D
0.700 80 Pasture/grassland/range, Good, HSG D
2.200 78 Weighted Average
2.200 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
6.4 100 0.0500 0.26 Sheet Flow,
Grass: Short n= 0.150 P2= 3.55"
3.0 860 0.0200 4.73 23.67 Channel Flow,
Area= 5.0 sf Perim= 9.0' r= 0.56'
n= 0.030 Earth, grassed & winding
5.0 260 0.0300 0.87 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
14.4 1,220 Total
Subcatchment 2S: Pre DA 2
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.18"
Runoff Area=2.200 ac
Runoff Volume=0.685 af
Runoff Depth=3.74"
Flow Length=1,220'
Tc=14.4 min
CN=78
10.73 cfs
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 30HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Post DA 1 Controlled
[49] Hint: Tc<2dt may require smaller dt
Runoff = 56.28 cfs @ 11.95 hrs, Volume= 2.704 af, Depth= 4.26"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.18"
Area (ac) CN Description
4.560 98 Paved roads w/curbs & sewers, HSG B
3.060 61 >75% Grass cover, Good, HSG B
7.620 83 Weighted Average
3.060 40.16% Pervious Area
4.560 59.84% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 4S: Post DA 1 Controlled
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)60
55
50
45
40
35
30
25
20
15
10
5
0
Type II 24-hr
25-Year Rainfall=6.18"
Runoff Area=7.620 ac
Runoff Volume=2.704 af
Runoff Depth=4.26"
Tc=5.0 min
CN=83
56.28 cfs
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 32HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA 1 Sheet Flow
Runoff = 18.45 cfs @ 12.01 hrs, Volume= 1.021 af, Depth= 3.64"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.18"
Area (ac) CN Description
1.500 77 Woods, Good, HSG D
1.500 80 >75% Grass cover, Good, HSG D
0.370 61 >75% Grass cover, Good, HSG B
3.370 77 Weighted Average
3.370 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 Direct Entry,
Subcatchment 7S: Post DA 1 Sheet Flow
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.18"
Runoff Area=3.370 ac
Runoff Volume=1.021 af
Runoff Depth=3.64"
Tc=10.0 min
CN=77
18.45 cfs
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 34HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA 2
[49] Hint: Tc<2dt may require smaller dt
Runoff = 4.85 cfs @ 11.96 hrs, Volume= 0.227 af, Depth= 3.64"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.18"
Area (ac) CN Description
0.750 77 Woods, Good, HSG D
0.750 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 260 0.0300 0.87 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 8S: Post DA 2
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.18"
Runoff Area=0.750 ac
Runoff Volume=0.227 af
Runoff Depth=3.64"
Flow Length=260'
Slope=0.0300 '/'
Tc=5.0 min
CN=77
4.85 cfs
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 36HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 5P: Pond 1
Inflow Area = 7.620 ac, 59.84% Impervious, Inflow Depth = 4.26" for 25-Year event
Inflow = 56.28 cfs @ 11.95 hrs, Volume= 2.704 af
Outflow = 17.36 cfs @ 12.09 hrs, Volume= 2.616 af, Atten= 69%, Lag= 7.9 min
Primary = 17.36 cfs @ 12.09 hrs, Volume= 2.616 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 627.77' @ 12.09 hrs Surf.Area= 14,890 sf Storage= 50,459 cf
Plug-Flow detention time= 290.7 min calculated for 2.614 af (97% of inflow)
Center-of-Mass det. time= 272.9 min ( 1,074.0 - 801.1 )
Volume Invert Avail.Storage Storage Description
#1 623.50' 78,405 cf Above Permanent Pool (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
623.50 8,755 0 0
629.50 17,380 78,405 78,405
Device Routing Invert Outlet Devices
#1 Primary 623.50'18.0" Round Culvert
L= 75.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 623.50' / 623.00' S= 0.0067 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 623.50'2.2" Vert. Orifice/Grate C= 0.600
#3 Device 1 625.41'36.0" W x 28.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 627.75'20.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 628.25'70.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=17.33 cfs @ 12.09 hrs HW=627.76' TW=0.00' (Dynamic Tailwater)
1=Culvert (Barrel Controls 17.33 cfs @ 9.81 fps)
2=Orifice/Grate (Passes < 0.26 cfs potential flow)
3=Orifice/Grate (Passes < 34.62 cfs potential flow)
4=Sharp-Crested Rectangular Weir (Passes < 0.04 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=623.50' TW=0.00' (Dynamic Tailwater)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 37HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Pond 5P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=7.620 ac
Peak Elev=627.77'
Storage=50,459 cf
56.28 cfs
17.36 cfs
17.36 cfs
0.00 cfs
Pond 5P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
250200150100500Elevation (feet)629
628
627
626
625
624 Culvert + Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 39HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Hydrograph for Pond 5P: Pond 1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 0 623.50 0.00 0.00 0.00
2.50 0.00 0 623.50 0.00 0.00 0.00
5.00 0.00 0 623.50 0.00 0.00 0.00
7.50 0.21 764 623.59 0.01 0.01 0.00
10.00 0.81 4,381 623.98 0.08 0.08 0.00
12.50 4.41 36,868 626.81 14.59 14.59 0.00
15.00 1.32 22,421 625.67 1.48 1.48 0.00
17.50 0.85 21,429 625.59 0.91 0.91 0.00
20.00 0.58 20,885 625.54 0.64 0.64 0.00
22.50 0.52 20,636 625.52 0.54 0.54 0.00
25.00 0.00 19,544 625.43 0.19 0.19 0.00
27.50 0.00 18,013 625.29 0.17 0.17 0.00
30.00 0.00 16,550 625.16 0.16 0.16 0.00
32.50 0.00 15,145 625.04 0.15 0.15 0.00
35.00 0.00 13,800 624.91 0.15 0.15 0.00
37.50 0.00 12,516 624.79 0.14 0.14 0.00
40.00 0.00 11,294 624.68 0.13 0.13 0.00
42.50 0.00 10,134 624.56 0.13 0.13 0.00
45.00 0.00 9,037 624.46 0.12 0.12 0.00
47.50 0.00 8,006 624.35 0.11 0.11 0.00
50.00 0.00 7,039 624.26 0.10 0.10 0.00
52.50 0.00 6,140 624.16 0.10 0.10 0.00
55.00 0.00 5,307 624.08 0.09 0.09 0.00
57.50 0.00 4,543 624.00 0.08 0.08 0.00
60.00 0.00 3,848 623.92 0.07 0.07 0.00
Type II 24-hr 25-Year Rainfall=6.18"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 42HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Link 6L: POI 1 Combined
Inflow Area = 10.990 ac, 41.49% Impervious, Inflow Depth > 3.97" for 25-Year event
Inflow = 35.39 cfs @ 12.02 hrs, Volume= 3.637 af
Primary = 35.39 cfs @ 12.02 hrs, Volume= 3.637 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Link 6L: POI 1 Combined
Inflow
Primary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=10.990 ac
35.39 cfs
35.39 cfs
Type II 24-hr 100-Year Rainfall=7.80"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 44HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-60.00 hrs, dt=0.05 hrs, 1201 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Runoff Area=9.550 ac 0.00% Impervious Runoff Depth=5.32"Subcatchment 1S: Pre DA 1
Flow Length=1,778' Tc=22.4 min CN=79 Runoff=52.30 cfs 4.235 af
Runoff Area=2.200 ac 0.00% Impervious Runoff Depth=5.21"Subcatchment 2S: Pre DA 2
Flow Length=1,220' Tc=14.4 min CN=78 Runoff=14.81 cfs 0.955 af
Runoff Area=7.620 ac 59.84% Impervious Runoff Depth=5.79"Subcatchment 4S: Post DA 1 Controlled
Tc=5.0 min CN=83 Runoff=75.12 cfs 3.675 af
Runoff Area=3.370 ac 0.00% Impervious Runoff Depth=5.09"Subcatchment 7S: Post DA 1 Sheet Flow
Tc=10.0 min CN=77 Runoff=25.55 cfs 1.430 af
Runoff Area=0.750 ac 0.00% Impervious Runoff Depth=5.09"Subcatchment 8S: Post DA 2
Flow Length=260' Slope=0.0300 '/' Tc=5.0 min CN=77 Runoff=6.69 cfs 0.318 af
Peak Elev=628.54' Storage=62,372 cf Inflow=75.12 cfs 3.675 afPond 5P: Pond 1
Primary=19.29 cfs 3.370 af Secondary=27.43 cfs 0.215 af Outflow=46.72 cfs 3.585 af
Inflow=71.04 cfs 5.015 afLink 6L: POI 1 Combined
Primary=71.04 cfs 5.015 af
Total Runoff Area = 23.490 ac Runoff Volume = 10.612 af Average Runoff Depth = 5.42"
80.59% Pervious = 18.930 ac 19.41% Impervious = 4.560 ac
Type II 24-hr 100-Year Rainfall=7.80"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 49HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Post DA 1 Controlled
[49] Hint: Tc<2dt may require smaller dt
Runoff = 75.12 cfs @ 11.95 hrs, Volume= 3.675 af, Depth= 5.79"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.80"
Area (ac) CN Description
4.560 98 Paved roads w/curbs & sewers, HSG B
3.060 61 >75% Grass cover, Good, HSG B
7.620 83 Weighted Average
3.060 40.16% Pervious Area
4.560 59.84% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 4S: Post DA 1 Controlled
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Type II 24-hr
100-Year Rainfall=7.80"
Runoff Area=7.620 ac
Runoff Volume=3.675 af
Runoff Depth=5.79"
Tc=5.0 min
CN=83
75.12 cfs
Type II 24-hr 100-Year Rainfall=7.80"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 55HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 5P: Pond 1
Inflow Area = 7.620 ac, 59.84% Impervious, Inflow Depth = 5.79" for 100-Year event
Inflow = 75.12 cfs @ 11.95 hrs, Volume= 3.675 af
Outflow = 46.72 cfs @ 12.05 hrs, Volume= 3.585 af, Atten= 38%, Lag= 5.6 min
Primary = 19.29 cfs @ 12.05 hrs, Volume= 3.370 af
Secondary = 27.43 cfs @ 12.05 hrs, Volume= 0.215 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.05 hrs
Peak Elev= 628.54' @ 12.05 hrs Surf.Area= 15,999 sf Storage= 62,372 cf
Plug-Flow detention time= 226.9 min calculated for 3.585 af (98% of inflow)
Center-of-Mass det. time= 212.0 min ( 1,004.4 - 792.4 )
Volume Invert Avail.Storage Storage Description
#1 623.50' 78,405 cf Above Permanent Pool (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
623.50 8,755 0 0
629.50 17,380 78,405 78,405
Device Routing Invert Outlet Devices
#1 Primary 623.50'18.0" Round Culvert
L= 75.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 623.50' / 623.00' S= 0.0067 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 623.50'2.2" Vert. Orifice/Grate C= 0.600
#3 Device 1 625.41'36.0" W x 28.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 627.75'20.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 628.25'70.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=19.27 cfs @ 12.05 hrs HW=628.53' TW=0.00' (Dynamic Tailwater)
1=Culvert (Barrel Controls 19.27 cfs @ 10.91 fps)
2=Orifice/Grate (Passes < 0.28 cfs potential flow)
3=Orifice/Grate (Passes < 46.36 cfs potential flow)
4=Sharp-Crested Rectangular Weir (Passes < 44.76 cfs potential flow)
Secondary OutFlow Max=26.40 cfs @ 12.05 hrs HW=628.53' TW=0.00' (Dynamic Tailwater)
5=Broad-Crested Rectangular Weir (Weir Controls 26.40 cfs @ 1.34 fps)
Type II 24-hr 100-Year Rainfall=7.80"NCC172107 - Poplin Road - 180731
Printed 8/2/2018Prepared by Bohler Engineering
Page 56HydroCAD® 10.00-20 s/n 08311 © 2017 HydroCAD Software Solutions LLC
Pond 5P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420Flow (cfs)80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=7.620 ac
Peak Elev=628.54'
Storage=62,372 cf
75.12 cfs
46.72 cfs
19.29 cfs
27.43 cfs
Pond 5P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
250200150100500Elevation (feet)629
628
627
626
625
624 Culvert + Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
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Temporary Sediment Trap #1
0.98 Disturbed Area (Acres)
4.44 Peak Flow from 10-year Storm (cfs)
3528 Required Volume ft3
1934 Required Surface Area ft2
31.1 Suggested Width ft
62.2 Suggested Length ft
32 Trial Top Width at Spillway Invert ft
64 Trial Top Length at Spillway Invert ft
2 Trial Side Slope Ratio Z:1
3.5 Trial Depth ft (1.5 feet below grade + 2 to 3.5 feet above grade)
18 Bottom Width ft
50 Bottom Length ft
900 Bottom Area ft2
5045 Actual Volume ft3 Okay
2048 Actual Surface Area ft2 Okay
5 Trial Weir Length ft
0.5 Trial Depth of Flow ft
5.3 Spillway Capacity cfs Okay
Temporary Sediment Trap #2
1.55 Disturbed Area (Acres)
7.0 Peak Flow from 10-year Storm (cfs)
5580 Required Volume ft3
3059 Required Surface Area ft2
39.1 Suggested Width ft
78.2 Suggested Length ft
40 Trial Top Width at Spillway Invert ft
80 Trial Top Length at Spillway Invert ft
2 Trial Side Slope Ratio Z:1
5 Trial Depth ft (1.5 feet below grade + 2 to 3.5 feet above grade)
20 Bottom Width ft
60 Bottom Length ft
1200 Bottom Area ft2
10667 Actual Volume ft3 Okay
3200 Actual Surface Area ft2 Okay
7 Trial Weir Length ft
0.5 Trial Depth of Flow ft
7.4 Spillway Capacity cfs Okay
Q = ciA
6.38 Disturbed Area (Acres) i 7.55
28.9 Peak Flow from 10-year Storm (cfs) C 0.6
11484 Required Volume ft3
9393 Required Surface Area ft2
68.5 Suggested Width ft
137.1 Suggested Length ft
104 Trial Top Width at Spillway Invert ft
208 Trial Top Length at Spillway Invert ft
3 Trial Side Slope Ratio Z:1
11 Trial Depth ft (2 to 13 feet above grade)
38 Bottom Width ft
142 Bottom Length ft
5396 Bottom Area ft2
140668 Actual Volume ft3 Okay
17380 Actual Surface Area ft2 Okay
70 Trial Weir Length ft
0.5 Trial Depth of Flow ft
74.2 Spillway Capacity cfs Okay
2 Skimmer Size (inches) Skimmer Size
0.167 Head on Skimmer (feet) (Inches)
2.25 Orifice Size (1/4 inch increments) 1.5
2.40 Dewatering Time (days) 2
Suggest about 3 days 2.5
3
4
5
6
8
SKIMMER BASIN #1
Poplin Meadows
Project:
Location:
Project Number:
Date:
Designed:ATZ
Checked:MT
Outlet ID:
Pipe diameter=36 inches
Pipe slope=0.5 %
Roughness Coef.=0.013
Full Flow Capacity=52.02 cfs
Full flow velocity=7.36 ft/sec
Zone from graph above =3
Is grade of apron 10% or more:n Y/N
3 Length =24.0 ft.
Outlet pipe diameter=36 in.Width at Outlet =9.0 ft.
Outlet flowrate=52.0 cfs Width at end of Pad=36.7 ft.
Outlet velocity=7.36 ft/sec Stone diameter =10 in.
Material =Class I Thickness =15 in.
Zone Material Diameter Thickness Length
1 Class A 4 6 4 x D(o)
2 Class B 8 12 6 x D(o)
3 Class I 10 15 8 x D(o)
4 Class I 10 15 8 x D(o)
5 Class II 14 21 10 x D(o)
6 Class II 14 21 10 x D(o)
7
Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
Special study required
Jun-07-2018
RRA
Inlcudes 1.1 Factor of Safety
Zone used =
NCC172107
Riprap Outlet Protection Design
Poplin Subdivision
Indian Trail, NC
7.4 ft/sec
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9 10Velocity (ft/sec)Pipe diameter (ft)
Figure 8.06.b.1
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Project:
Location:
Project Number:
Date:
Designed:ATZ
Checked:MT
Outlet ID:
Pipe diameter=15 inches
Pipe slope=0.5 %
Roughness Coef.=0.013
Full Flow Capacity=5.04 cfs
Full flow velocity=4.11 ft/sec
Zone from graph above =1
Is grade of apron 10% or more:n Y/N
1 Length =5.0 ft.
Outlet pipe diameter=15 in.Width at Outlet =3.8 ft.
Outlet flowrate=5.0 cfs Width at end of Pad=9.5 ft.
Outlet velocity=4.11 ft/sec Stone diameter =4 in.
Material =Class A Thickness =6 in.
Zone Material Diameter Thickness Length
1 Class A 4 6 4 x D(o)
2 Class B 8 12 6 x D(o)
3 Class I 10 15 8 x D(o)
4 Class I 10 15 8 x D(o)
5 Class II 14 21 10 x D(o)
6 Class II 14 21 10 x D(o)
7
Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
NCC172107
Riprap Outlet Protection Design
Poplin Subdivision
Indian Trail, NC
Special study required
Jun-07-2018
RRB
Inlcudes 1.1 Factor of Safety
Zone used =
4.1 ft/sec
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9 10Velocity (ft/sec)Pipe diameter (ft)
Figure 8.06.b.1
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7