SW3180302_Stormwater Report - 180302_20180319

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

STORMWATER MANAGEMENT REPORT
PREPARED FOR:

H&H HOMES
WAXHAW HWY
WAXHAW, NC
UNION COUNTY
BEPC #NCC172039

March 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 Waxhaw Highway, in Union County. The project site is
currently vacant and consists of approximately 19.024 acres and will include approximately 117
single family lots. There is a 100 ft CSX right of way surrounding an in-use railroad along the
rear perimeter of the property.

The majority of the site is wooded with average existing slopes of 5% to 20%. There is
currently 1 possible stormwater measure provided on the site. Located on the northend of the
property is 1 dry detention pond that takes water from the property and directs it thru a culvert
underneath CSX railroad 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 directly adjacent to Blythe 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.

Stormwater systems shall also be installed to treat the channel protection volume leaving the
project for the one-year, 24-hour storm. The peak discharge is attenuated for both the 2-year,
6-hr storm and the 10-year, 6-hr storm events. The 50-year, 6-hr storm events have been
analyzed to provide 1’ of freeboard to the top of berm. Also, due to elevation discharge
locations, the 100-year, 6-hr storm has been analyzed to ensure it does not overtop the
downstream CSX railroad culverts.

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 ponds. 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.

4

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
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 6
HR(cfs)
10-YR 6
HR(cfs)
POI 1 COMBINED:
PRE DA 1A,1B COMBINED 10.20 28.42
POST DA 1B,1A sheet, 1A
controlled COMBINED 10.20 23.67
POI 2:
PRE DA 2 2.46 10.11
POST DA 2 2.32 7.47
POI 3:
PRE DA 3 0.30 1.49
POST DA 3 0.78 1.78
POI 4:
PRE DA 4 0.47 4.02
POST DA 4 COMBINED 0.32 2.00

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

5

VOLUME CONTROL

Volume control of the channel protection volume for the 1-yr, 24-hr storm, as well as treatment
of the 1” water quality volume, are also provided within the proposed above-ground wet
detention ponds. Please see the table below for the required Channel Protection Volume
requirements for the 1-year, 24-hour storm.

Requirements:
50% of CPV must be present in system at 24 hours after the peak rainfall of the 1-yr, 24-hr
event (36 hours)
5% of CPV must be present in system at 48 hours after the peak rainfall of the 1-yr,24-hr event
(60 hours)

Controlled Drainage
Area
50% CPV
(36 hours)
(cf)
5% CPV
(60 hours)
(cf)
DA 1 (Pond 1 West):
Required 13,085 1,308
Provided 43,049 24,181
DA 4 (Pond 2 East):
Required 3,975 397
Provided 10,460 6,301

6

Appendix
DESIGN:
GIVEN:
11.32 Ac.
65%
3.4 FEET
65%
SA/DA = 2.11 % = 0.0211 Updated MDC
SA REQUIRED = 11.32 Ac. X 0.0211
= 0.24 Ac.
= 10,403 SF
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
Design Rainfall = 1 Inch
Drainage Area = 11.32 Acres
Rv = 0.05 + 0.9(I)
I = Percent Impervious = 65%
Rv = 0.64 in./in.
V1 =0.601 acre-feet = 26,171
ft3
Pond Height above Orifice = 632.50 feet
Orifice Invert Elevation = 631.50 feet
Orifice Diameter (D) = 3.00 inches = 0.25 feet
Orifice Area (a) = 0.0491 square feet
Gravitational Constant (g) = 32.2 ft/sec2
Head (H) = 0.88 feet
Driving Head (HO) =0.292 feet
Discharge Coefficient (CD) =0.6
Drawdown rate (Q) = 0.128 cfs
Time (t) = 205,031 seconds = 2.37 days
Note:
The above calculation is based on the orifice equation where:
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
WET POND #1 H&H Homes (WAXHAW, NC)
WATER QUALITY TO MEET 85% TSS REMOVAL
Self-Storage FacilityLAND USE =
ESTIMATED PERCENT IMPERVIOUS =
DRAINAGE AREA TO FACILITY =
3) Pond Drawdown Time
ALLOCATED AS A PERMANENT POOL
V1 = (Design Rainfall)(Rv)(Drainage Area)
3/5/2018 8:44 AM Page 1 of 1
Elev Area (sf)Inc Storage (cf)Total Storage (cf)
631.50 32,265 0 0
632.50 34,973 33,619 33,619
633.50 37,739 36,356 69,975
634.50 40,562 39,151 109,126
635.50 43,441 42,002 151,127
636.00 44,902 22,086 173,213
Elev Area (sf) Inc Storage (cf) Total Storage (cf)
626.00 15,851 0 0
626.50 16,385 0 0
627.50 17,474 16,930 16,930
629.50 19,746 37,220 54,150
630.50 20,928 20,337 74,487
631.50 32,265 29,662 119,105
Elev Area (sf) Inc Storage (cf) Total Storage (cf)
627.00 3,150 0 0
627.00 3,150 0 0
627.50 3,445 1,649 1,649
629.50 4,757 8,202 9,851
630.50 5,455 5,106 14,957
Wet Pond 1 Design
Wet Pond 1 Treatment Volume
Wet Pond 1 Permanent Pool - Forebay
Wet Pond 1 Permanent Pool Volume - Main Pool
3/5/2018 8:44 AM Page 1 of 1
DESIGN:
GIVEN:
3.41 Ac.
66%
4.0 FEET
66%
SA/DA = 1.93 % = 0.0193 updated MDC
SA REQUIRED = 3.41 Ac. X 0.0193
= 0.07 Ac.
= 2,864 SF
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
Design Rainfall = 1 Inch
Drainage Area = 3.41 Acres
Rv = 0.05 + 0.9(I)
I = Percent Impervious = 66%
Rv = 0.64 in./in.
V1 =0.183 acre-feet = 7,951
ft3
Pond Height above Orifice = 623.00 feet
Orifice Invert Elevation = 622.00 feet
Orifice Diameter (D) = 1.75 inches = 0.15 feet
Orifice Area (a) = 0.0167 square feet
Gravitational Constant (g) = 32.2 ft/sec2
Head (H) = 0.93 feet
Driving Head (HO) =0.309 feet
Discharge Coefficient (CD) =0.6
Drawdown rate (Q) = 0.045 cfs
Time (t) = 177,836 seconds = 2.06 days
Note:
The above calculation is based on the orifice equation where:
WET POND #2 WAXHAW, NC)
WATER QUALITY TO MEET 85% TSS REMOVAL
DRAINAGE AREA TO FACILITY =
LAND USE = Self-Storage Facility
ESTIMATED PERCENT IMPERVIOUS =
1) SA/DA RATIO:
AVERAGE POOL DEPTH =
PERCENT IMPERVIOUS =
2) TEMPORARY WATER QUALITY POOL REQUIREMENTS
PROVIDE VOLUME TO DETAIN THE 1" STORM EVENT ABOVE THE ELEVATION
ALLOCATED AS A PERMANENT POOL
V1 = (Design Rainfall)(Rv)(Drainage Area)
3) Pond Drawdown Time
3/5/2018 8:45 AM Page 1 of 1
Elev Area (sf)Inc Storage (cf)Total Storage (cf)
622.00 7,948 0 0
623.00 9,562 8,755 8,755
624.00 11,232 10,397 19,152
625.00 12,958 12,095 31,247
626.00 14,741 13,850 45,097
626.00 14,741 0 45,097
Elev Area (sf) Inc Storage (cf) Total Storage (cf)
616.50 1,151 0 0
617.00 1,514 0 0
619.00 2,399 3,913 3,913
620.00 2,926 2,663 6,576
621.00 3,511 3,219 9,794
622.00 7,948 6,457 20,214
Elev Area (sf) Inc Storage (cf) Total Storage (cf)
616.50 435 0 0
617.00 588 0 0
619.00 967 1,555 1,555
620.00 1,198 1,083 2,638
621.00 1,454 1,326 3,964
Wet Pond 2 Design
Wet Pond 1 Treatment Volume
Wet Pond 1 Permanent Pool Volume - Main Pool
Wet Pond 1 Permanent Pool - Forebay
3/5/2018 8:45 AM Page 1 of 1
14S
Post DA 1 Mod CN
15S
Post DA 4 Mod CN
2P
Pond 1
4P
Pond 2
Routing Diagram for H&H Waxhaw - 180228
Prepared by Bohler Engineering, Printed 3/1/2018
HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 2HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Area Listing (selected nodes)
Area
(acres)
CN Description
(subcatchment-numbers)
14.350 97 (14S, 15S)
14.350 97 TOTAL AREA
H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 5HydroCAD® 10.00-20 s/n 08583 © 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 2P 630.50 625.50 400.0 0.0125 0.013 18.0 0.0 0.0
2 4P 615.15 611.44 310.0 0.0120 0.013 15.0 0.0 0.0
Charlotte 1-in 6-hr 1in - 6hr Rainfall=1.00"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 6HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=11.320 ac 0.00% Impervious Runoff Depth=0.71"Subcatchment 14S: Post DA 1 Mod CN
Tc=5.0 min CN=97 Runoff=17.98 cfs 0.666 af
Runoff Area=3.030 ac 0.00% Impervious Runoff Depth=0.71"Subcatchment 15S: Post DA 4 Mod CN
Tc=5.0 min CN=97 Runoff=4.81 cfs 0.178 af
Peak Elev=632.20' Storage=26,892 cf Inflow=17.98 cfs 0.666 afPond 2P: Pond 1
Primary=0.20 cfs 0.663 af Secondary=0.00 cfs 0.000 af Outflow=0.20 cfs 0.663 af
Peak Elev=622.63' Storage=7,175 cf Inflow=4.81 cfs 0.178 afPond 4P: Pond 2
Primary=0.06 cfs 0.173 af Secondary=0.00 cfs 0.000 af Outflow=0.06 cfs 0.173 af
Total Runoff Area = 14.350 ac Runoff Volume = 0.844 af Average Runoff Depth = 0.71"
100.00% Pervious = 14.350 ac 0.00% Impervious = 0.000 ac
Charlotte 1-in 6-hr 1in - 6hr Rainfall=1.00"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 12HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Hydrograph for Pond 2P: Pond 1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 0 631.50 0.00 0.00 0.00
4.00 1.16 23,520 632.11 0.18 0.18 0.00
8.00 0.00 25,541 632.16 0.19 0.19 0.00
12.00 0.00 22,847 632.09 0.18 0.18 0.00
16.00 0.00 20,303 632.03 0.17 0.17 0.00
20.00 0.00 17,910 631.96 0.16 0.16 0.00
24.00 0.00 15,667 631.91 0.15 0.15 0.00
28.00 0.00 13,573 631.85 0.14 0.14 0.00
32.00 0.00 11,631 631.80 0.13 0.13 0.00
36.00 0.00 9,838 631.75 0.12 0.12 0.00
40.00 0.00 8,195 631.71 0.11 0.11 0.00
44.00 0.00 6,703 631.67 0.10 0.10 0.00
48.00 0.00 5,362 631.64 0.09 0.09 0.00
52.00 0.00 4,178 631.61 0.08 0.08 0.00
56.00 0.00 3,165 631.58 0.06 0.06 0.00
60.00 0.00 2,426 631.56 0.04 0.04 0.00
64.00 0.00 1,917 631.55 0.03 0.03 0.00
68.00 0.00 1,559 631.54 0.02 0.02 0.00
72.00 0.00 1,272 631.53 0.02 0.02 0.00
76.00 0.00 1,038 631.53 0.01 0.01 0.00
80.00 0.00 847 631.52 0.01 0.01 0.00
84.00 0.00 691 631.52 0.01 0.01 0.00
88.00 0.00 564 631.51 0.01 0.01 0.00
92.00 0.00 460 631.51 0.01 0.01 0.00
96.00 0.00 375 631.51 0.01 0.01 0.00
100.00 0.00 306 631.51 0.00 0.00 0.00
104.00 0.00 250 631.51 0.00 0.00 0.00
108.00 0.00 204 631.51 0.00 0.00 0.00
112.00 0.00 166 631.50 0.00 0.00 0.00
116.00 0.00 136 631.50 0.00 0.00 0.00
120.00 0.00 111 631.50 0.00 0.00 0.00
Charlotte 1-in 6-hr 1in - 6hr Rainfall=1.00"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 16HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Hydrograph for Pond 4P: Pond 2
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 0 622.00 0.00 0.00 0.00
4.00 0.31 6,301 622.56 0.05 0.05 0.00
8.00 0.00 6,786 622.60 0.06 0.06 0.00
12.00 0.00 6,019 622.53 0.05 0.05 0.00
16.00 0.00 5,305 622.47 0.05 0.05 0.00
20.00 0.00 4,643 622.41 0.04 0.04 0.00
24.00 0.00 4,033 622.36 0.04 0.04 0.00
28.00 0.00 3,477 622.31 0.04 0.04 0.00
32.00 0.00 2,973 622.26 0.03 0.03 0.00
36.00 0.00 2,522 622.22 0.03 0.03 0.00
40.00 0.00 2,124 622.19 0.03 0.03 0.00
44.00 0.00 1,778 622.16 0.02 0.02 0.00
48.00 0.00 1,487 622.13 0.02 0.02 0.00
52.00 0.00 1,247 622.11 0.01 0.01 0.00
56.00 0.00 1,058 622.09 0.01 0.01 0.00
60.00 0.00 912 622.08 0.01 0.01 0.00
64.00 0.00 796 622.07 0.01 0.01 0.00
68.00 0.00 701 622.06 0.01 0.01 0.00
72.00 0.00 624 622.05 0.00 0.00 0.00
76.00 0.00 560 622.05 0.00 0.00 0.00
80.00 0.00 508 622.04 0.00 0.00 0.00
84.00 0.00 466 622.04 0.00 0.00 0.00
88.00 0.00 430 622.04 0.00 0.00 0.00
92.00 0.00 398 622.04 0.00 0.00 0.00
96.00 0.00 367 622.03 0.00 0.00 0.00
100.00 0.00 340 622.03 0.00 0.00 0.00
104.00 0.00 314 622.03 0.00 0.00 0.00
108.00 0.00 290 622.03 0.00 0.00 0.00
112.00 0.00 268 622.02 0.00 0.00 0.00
116.00 0.00 248 622.02 0.00 0.00 0.00
120.00 0.00 229 622.02 0.00 0.00 0.00
Charlotte 1-in 6-hr 1in - 6hr Rainfall=1.00"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 9HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 2P: Pond 1
Inflow Area = 11.320 ac, 0.00% Impervious, Inflow Depth = 0.71" for 1in - 6hr event
Inflow = 17.98 cfs @ 3.15 hrs, Volume= 0.666 af
Outflow = 0.20 cfs @ 6.03 hrs, Volume= 0.663 af, Atten= 99%, Lag= 172.7 min
Primary = 0.20 cfs @ 6.03 hrs, Volume= 0.663 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 632.20' @ 6.03 hrs Surf.Area= 34,222 sf Storage= 26,892 cf
Plug-Flow detention time= 1,594.9 min calculated for 0.663 af (100% of inflow)
Center-of-Mass det. time= 1,594.3 min ( 1,800.8 - 206.5 )
Volume Invert Avail.Storage Storage Description
#1 631.50' 173,626 cf Main Pool Above Forebay Berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.50 32,265 0 0
636.00 44,902 173,626 173,626
Device Routing Invert Outlet Devices
#1 Primary 630.50'18.0" Round Culvert
L= 400.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 630.50' / 625.50' S= 0.0125 '/' Cc= 0.900
n= 0.013 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 631.50'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 633.00'12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 635.00'16.0' long Sharp-Crested Rectangular Weir 0 End Contraction(s)
#5 Secondary 635.50'20.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.20 cfs @ 6.03 hrs HW=632.20' (Free Discharge)
1=Culvert (Passes 0.20 cfs of 10.35 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.20 cfs @ 4.02 fps)
3=Orifice/Grate ( Controls 0.00 cfs)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.50' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 1-in 6-hr 1in - 6hr Rainfall=1.00"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 10HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 2P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=11.320 ac
Peak Elev=632.20'
Storage=26,892 cf
17.98 cfs
0.20 cfs
0.20 cfs
0.00 cfs
Pond 2P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302520151050Elevation (feet)636
635
634
633
632
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 1-in 6-hr 1in - 6hr Rainfall=1.00"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 12HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 4P: Pond 2
Inflow Area = 3.030 ac, 0.00% Impervious, Inflow Depth = 0.71" for 1in - 6hr event
Inflow = 4.81 cfs @ 3.15 hrs, Volume= 0.178 af
Outflow = 0.06 cfs @ 6.03 hrs, Volume= 0.173 af, Atten= 99%, Lag= 172.4 min
Primary = 0.06 cfs @ 6.03 hrs, Volume= 0.173 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 622.63' @ 6.03 hrs Surf.Area= 9,022 sf Storage= 7,175 cf
Plug-Flow detention time= 1,561.3 min calculated for 0.173 af (97% of inflow)
Center-of-Mass det. time= 1,558.8 min ( 1,765.3 - 206.5 )
Volume Invert Avail.Storage Storage Description
#1 622.00' 45,378 cf Main pool above forebay berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
622.00 7,948 0 0
626.00 14,741 45,378 45,378
Device Routing Invert Outlet Devices
#1 Primary 615.15'15.0" Round Culvert
L= 310.0' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 615.15' / 611.44' S= 0.0120 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 622.00'1.7" Vert. Orifice/Grate C= 0.600
#3 Device 1 623.00'3.0" Vert. Orifice/Grate C= 0.600
#4 Device 1 624.75'16.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 625.50'20.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Primary OutFlow Max=0.06 cfs @ 6.03 hrs HW=622.63' (Free Discharge)
1=Culvert (Passes 0.06 cfs of 10.51 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.06 cfs @ 3.61 fps)
3=Orifice/Grate ( Controls 0.00 cfs)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=622.00' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
1S
Pre DA 1A
2S
Pre DA 1B
3S
Pre DA 2
4S
Pre DA 3
5S
Pre DA 4
6S
Post DA 1A Controlled
7S
Post DA 1A Sheet Flow
8S
Post DA 1B
9S
Post DA 2
10S
Post DA 3
11S
Post DA 4 Controlled
13S
Post DA 4 Sheet Flow
1P
CB
DS 24" Culvert
2P
Pond 1
3P
CB
DS 24" Culvert
4P
Pond 2
1L
POI 1 COMBINED
2L
POI 1 COMBINED
3L
POI 4
Routing Diagram for H&H Waxhaw - 180228
Prepared by Bohler Engineering, Printed 3/1/2018
HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 2HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Area Listing (selected nodes)
Area
(acres)
CN Description
(subcatchment-numbers)
11.160 61 >75% Grass cover, Good, HSG B (6S, 9S, 10S, 11S, 13S)
6.880 85 Adjacent Developed Property (8S)
0.680 98 Impervious (3S)
11.580 98 Paved parking, HSG B (1S, 4S, 5S, 6S, 9S, 10S, 11S)
6.370 65 Woods/grass comb., Fair, HSG B (3S)
37.060 58 Woods/grass comb., Good, HSG B (1S, 4S, 5S, 7S)
6.880 85 adj prop (2S)
80.610 70 TOTAL AREA
H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 3HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Soil Listing (selected nodes)
Area
(acres)
Soil
Group
Subcatchment
Numbers
0.000 HSG A
66.170 HSG B 1S, 3S, 4S, 5S, 6S, 7S, 9S, 10S, 11S, 13S
0.000 HSG C
0.000 HSG D
14.440 Other 2S, 3S, 8S
80.610 TOTAL AREA
H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 5HydroCAD® 10.00-20 s/n 08583 © 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 1P 622.81 622.21 60.0 0.0100 0.013 24.0 0.0 0.0
2 2P 630.50 625.50 400.0 0.0125 0.013 18.0 0.0 0.0
3 3P 622.81 622.21 60.0 0.0100 0.013 24.0 0.0 0.0
4 4P 615.15 611.44 310.0 0.0120 0.013 15.0 0.0 0.0
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 6HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=17.900 ac 2.79% Impervious Runoff Depth=0.29"Subcatchment 1S: Pre DA 1A
Flow Length=635' Tc=24.0 min CN=59 Runoff=2.43 cfs 0.427 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=1.55"Subcatchment 2S: Pre DA 1B
Tc=18.6 min CN=85 Runoff=12.28 cfs 0.887 af
Runoff Area=7.050 ac 9.65% Impervious Runoff Depth=0.60"Subcatchment 3S: Pre DA 2
Flow Length=1,795' Tc=15.5 min CN=68 Runoff=4.53 cfs 0.353 af
Runoff Area=0.860 ac 17.44% Impervious Runoff Depth=0.48"Subcatchment 4S: Pre DA 3
Flow Length=344' Tc=3.0 min CN=65 Runoff=0.72 cfs 0.035 af
Runoff Area=8.370 ac 2.99% Impervious Runoff Depth=0.29"Subcatchment 5S: Pre DA 4
Flow Length=2,170' Tc=34.6 min CN=59 Runoff=0.91 cfs 0.200 af
Runoff Area=11.320 ac 65.19% Impervious Runoff Depth=1.55"Subcatchment 6S: Post DA 1A Controlled
Tc=5.0 min CN=85 Runoff=31.91 cfs 1.459 af
Runoff Area=10.830 ac 0.00% Impervious Runoff Depth=0.26"Subcatchment 7S: Post DA 1A Sheet Flow
Flow Length=1,286' Tc=28.4 min CN=58 Runoff=1.08 cfs 0.233 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=1.55"Subcatchment 8S: Post DA 1B
Flow Length=340' Tc=18.6 min CN=85 Runoff=12.28 cfs 0.887 af
Runoff Area=3.840 ac 30.21% Impervious Runoff Depth=0.78"Subcatchment 9S: Post DA 2
Flow Length=100' Slope=0.0300 '/' Tc=13.0 min CN=72 Runoff=3.82 cfs 0.249 af
Runoff Area=0.550 ac 50.91% Impervious Runoff Depth=1.21"Subcatchment 10S: Post DA 3
Flow Length=35' Slope=0.0200 '/' Tc=9.0 min CN=80 Runoff=1.05 cfs 0.056 af
Runoff Area=3.020 ac 61.59% Impervious Runoff Depth=1.48"Subcatchment 11S: Post DA 4 Controlled
Tc=5.0 min CN=84 Runoff=8.14 cfs 0.371 af
Runoff Area=3.110 ac 0.00% Impervious Runoff Depth=0.35"Subcatchment 13S: Post DA 4 Sheet Flow
Tc=34.6 min CN=61 Runoff=0.48 cfs 0.090 af
Peak Elev=624.61' Inflow=13.82 cfs 1.313 afPond 1P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=13.82 cfs 1.313 af
Peak Elev=632.84' Storage=51,756 cf Inflow=31.91 cfs 1.459 afPond 2P: Pond 1
Primary=0.27 cfs 1.431 af Secondary=0.00 cfs 0.000 af Outflow=0.27 cfs 1.431 af
Peak Elev=624.53' Inflow=12.92 cfs 2.550 afPond 3P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=12.92 cfs 2.550 af
Peak Elev=623.10' Storage=12,480 cf Inflow=8.14 cfs 0.371 afPond 4P: Pond 2
Primary=0.10 cfs 0.360 af Secondary=0.00 cfs 0.000 af Outflow=0.10 cfs 0.360 af
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 7HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Inflow=13.82 cfs 1.313 afLink 1L: POI 1 COMBINED
Primary=13.82 cfs 1.313 af
Inflow=12.92 cfs 2.550 afLink 2L: POI 1 COMBINED
Primary=12.92 cfs 2.550 af
Inflow=0.54 cfs 0.450 afLink 3L: POI 4
Primary=0.54 cfs 0.450 af
Total Runoff Area = 80.610 ac Runoff Volume = 5.244 af Average Runoff Depth = 0.78"
84.79% Pervious = 68.350 ac 15.21% Impervious = 12.260 ac
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 8HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1A
Runoff = 2.43 cfs @ 12.27 hrs, Volume= 0.427 af, Depth= 0.29"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
17.400 58 Woods/grass comb., Good, HSG B
0.500 98 Paved parking, HSG B
17.900 59 Weighted Average
17.400 97.21% Pervious Area
0.500 2.79% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
9.8 535 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
24.0 635 Total
Subcatchment 1S: Pre DA 1A
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)2
1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=17.900 ac
Runoff Volume=0.427 af
Runoff Depth=0.29"
Flow Length=635'
Tc=24.0 min
CN=59
2.43 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 9HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 1B
Runoff = 12.28 cfs @ 12.11 hrs, Volume= 0.887 af, Depth= 1.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
* 6.880 85 adj prop
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
18.6 Direct Entry,
Subcatchment 2S: Pre DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=6.880 ac
Runoff Volume=0.887 af
Runoff Depth=1.55"
Tc=18.6 min
CN=85
12.28 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 10HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA 2
Runoff = 4.53 cfs @ 12.10 hrs, Volume= 0.353 af, Depth= 0.60"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
* 0.680 98 Impervious
6.370 65 Woods/grass comb., Fair, HSG B
7.050 68 Weighted Average
6.370 90.35% Pervious Area
0.680 9.65% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.1 100 0.0400 0.23 Sheet Flow, Pre Sheet grass
Grass: Short n= 0.150 P2= 3.50"
0.3 35 0.0700 1.85 Shallow Concentrated Flow, Pre Shallow Wooded
Short Grass Pasture Kv= 7.0 fps
8.1 1,660 0.0300 3.40 17.02 Channel Flow, roadside ditch
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
15.5 1,795 Total
Subcatchment 3S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)5
4
3
2
1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=7.050 ac
Runoff Volume=0.353 af
Runoff Depth=0.60"
Flow Length=1,795'
Tc=15.5 min
CN=68
4.53 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 11HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA 3
[49] Hint: Tc<2dt may require smaller dt
Runoff = 0.72 cfs @ 11.95 hrs, Volume= 0.035 af, Depth= 0.48"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
0.150 98 Paved parking, HSG B
0.710 58 Woods/grass comb., Good, HSG B
0.860 65 Weighted Average
0.710 82.56% Pervious Area
0.150 17.44% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 20 0.4000 0.19 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
1.3 324 0.7000 4.18 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
3.0 344 Total
Subcatchment 4S: Pre DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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 II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=0.860 ac
Runoff Volume=0.035 af
Runoff Depth=0.48"
Flow Length=344'
Tc=3.0 min
CN=65
0.72 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 12HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Pre DA 4
Runoff = 0.91 cfs @ 12.44 hrs, Volume= 0.200 af, Depth= 0.29"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
8.120 58 Woods/grass comb., Good, HSG B
8.370 59 Weighted Average
8.120 97.01% Pervious Area
0.250 2.99% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
10.0 670 0.0500 1.12 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
10.4 1,400 0.0130 2.24 11.21 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
34.6 2,170 Total
Subcatchment 5S: Pre DA 4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=8.370 ac
Runoff Volume=0.200 af
Runoff Depth=0.29"
Flow Length=2,170'
Tc=34.6 min
CN=59
0.91 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 13HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA 1A Controlled
Runoff = 31.91 cfs @ 11.96 hrs, Volume= 1.459 af, Depth= 1.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
7.380 98 Paved parking, HSG B
3.940 61 >75% Grass cover, Good, HSG B
11.320 85 Weighted Average
3.940 34.81% Pervious Area
7.380 65.19% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 6S: Post DA 1A Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=11.320 ac
Runoff Volume=1.459 af
Runoff Depth=1.55"
Tc=5.0 min
CN=85
31.91 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 14HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA 1A Sheet Flow
Runoff = 1.08 cfs @ 12.36 hrs, Volume= 0.233 af, Depth= 0.26"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
10.830 58 Woods/grass comb., Good, HSG B
10.830 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
17.5 100 0.0300 0.10 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
6.8 500 0.0600 1.22 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
4.1 686 0.0200 2.78 13.90 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
28.4 1,286 Total
Subcatchment 7S: Post DA 1A Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=10.830 ac
Runoff Volume=0.233 af
Runoff Depth=0.26"
Flow Length=1,286'
Tc=28.4 min
CN=58
1.08 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 15HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA 1B
Runoff = 12.28 cfs @ 12.11 hrs, Volume= 0.887 af, Depth= 1.55"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
* 6.880 85 Adjacent Developed Property
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
4.4 240 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
18.6 340 Total
Subcatchment 8S: Post DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=6.880 ac
Runoff Volume=0.887 af
Runoff Depth=1.55"
Flow Length=340'
Tc=18.6 min
CN=85
12.28 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 16HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 9S: Post DA 2
Runoff = 3.82 cfs @ 12.06 hrs, Volume= 0.249 af, Depth= 0.78"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
1.160 98 Paved parking, HSG B
2.680 61 >75% Grass cover, Good, HSG B
3.840 72 Weighted Average
2.680 69.79% Pervious Area
1.160 30.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
8.0 100 0.0300 0.21 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
13.0 100 Total
Subcatchment 9S: Post DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)4
3
2
1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=3.840 ac
Runoff Volume=0.249 af
Runoff Depth=0.78"
Flow Length=100'
Slope=0.0300 '/'
Tc=13.0 min
CN=72
3.82 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 17HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 10S: Post DA 3
Runoff = 1.05 cfs @ 12.01 hrs, Volume= 0.056 af, Depth= 1.21"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
0.280 98 Paved parking, HSG B
0.270 61 >75% Grass cover, Good, HSG B
0.550 80 Weighted Average
0.270 49.09% Pervious Area
0.280 50.91% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
4.0 35 0.0200 0.14 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
9.0 35 Total
Subcatchment 10S: Post DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=0.550 ac
Runoff Volume=0.056 af
Runoff Depth=1.21"
Flow Length=35'
Slope=0.0200 '/'
Tc=9.0 min
CN=80
1.05 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 18HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 11S: Post DA 4 Controlled
Runoff = 8.14 cfs @ 11.96 hrs, Volume= 0.371 af, Depth= 1.48"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
1.860 98 Paved parking, HSG B
1.160 61 >75% Grass cover, Good, HSG B
3.020 84 Weighted Average
1.160 38.41% Pervious Area
1.860 61.59% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 11S: Post DA 4 Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)9
8
7
6
5
4
3
2
1
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=3.020 ac
Runoff Volume=0.371 af
Runoff Depth=1.48"
Tc=5.0 min
CN=84
8.14 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 19HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 13S: Post DA 4 Sheet Flow
Runoff = 0.48 cfs @ 12.42 hrs, Volume= 0.090 af, Depth= 0.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Type II 24-hr 1yr 24 hour Rainfall=2.95"
Area (ac) CN Description
* 3.110 61 >75% Grass cover, Good, HSG B
3.110 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
34.6 Direct Entry,
Subcatchment 13S: Post DA 4 Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Type II 24-hr
1yr 24 hour Rainfall=2.95"
Runoff Area=3.110 ac
Runoff Volume=0.090 af
Runoff Depth=0.35"
Tc=34.6 min
CN=61
0.48 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 20HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 1P: DS 24" Culvert
[57] Hint: Peaked at 624.61' (Flood elevation advised)
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 0.64" for 1yr 24 hour event
Inflow = 13.82 cfs @ 12.13 hrs, Volume= 1.313 af
Outflow = 13.82 cfs @ 12.13 hrs, Volume= 1.313 af, Atten= 0%, Lag= 0.0 min
Primary = 13.82 cfs @ 12.13 hrs, Volume= 1.313 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 624.61' @ 12.13 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=13.71 cfs @ 12.13 hrs HW=624.60' (Free Discharge)
1=Culvert (Barrel Controls 13.71 cfs @ 6.11 fps)
Pond 1P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=24.780 ac
Peak Elev=624.61'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
13.82 cfs
13.82 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 22HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 2P: Pond 1
Inflow Area = 11.320 ac, 65.19% Impervious, Inflow Depth = 1.55" for 1yr 24 hour event
Inflow = 31.91 cfs @ 11.96 hrs, Volume= 1.459 af
Outflow = 0.27 cfs @ 24.03 hrs, Volume= 1.431 af, Atten= 99%, Lag= 724.0 min
Primary = 0.27 cfs @ 24.03 hrs, Volume= 1.431 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 632.84' @ 24.03 hrs Surf.Area= 36,032 sf Storage= 51,756 cf
Plug-Flow detention time= 2,198.2 min calculated for 1.430 af (98% of inflow)
Center-of-Mass det. time= 2,187.9 min ( 3,013.6 - 825.7 )
Volume Invert Avail.Storage Storage Description
#1 631.50' 173,626 cf Main Pool Above Forebay Berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.50 32,265 0 0
636.00 44,902 173,626 173,626
Device Routing Invert Outlet Devices
#1 Primary 630.50'18.0" Round Culvert
L= 400.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 630.50' / 625.50' S= 0.0125 '/' Cc= 0.900
n= 0.013 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 631.50'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 633.00'12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 635.00'16.0' long Sharp-Crested Rectangular Weir 0 End Contraction(s)
#5 Secondary 635.50'20.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.27 cfs @ 24.03 hrs HW=632.84' (Free Discharge)
1=Culvert (Passes 0.27 cfs of 11.75 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.27 cfs @ 5.58 fps)
3=Orifice/Grate ( Controls 0.00 cfs)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.50' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 23HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 2P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=11.320 ac
Peak Elev=632.84'
Storage=51,756 cf
31.91 cfs
0.27 cfs
0.27 cfs
0.00 cfs
Pond 2P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302520151050Elevation (feet)636
635
634
633
632
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 25HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 3P: DS 24" Culvert
[57] Hint: Peaked at 624.53' (Flood elevation advised)
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 1.05" for 1yr 24 hour event
Inflow = 12.92 cfs @ 12.12 hrs, Volume= 2.550 af
Outflow = 12.92 cfs @ 12.12 hrs, Volume= 2.550 af, Atten= 0%, Lag= 0.0 min
Primary = 12.92 cfs @ 12.12 hrs, Volume= 2.550 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 624.53' @ 12.12 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=12.92 cfs @ 12.12 hrs HW=624.53' (Free Discharge)
1=Culvert (Barrel Controls 12.92 cfs @ 6.03 fps)
Pond 3P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=29.030 ac
Peak Elev=624.53'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
12.92 cfs
12.92 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 27HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 4P: Pond 2
Inflow Area = 3.020 ac, 61.59% Impervious, Inflow Depth = 1.48" for 1yr 24 hour event
Inflow = 8.14 cfs @ 11.96 hrs, Volume= 0.371 af
Outflow = 0.10 cfs @ 19.90 hrs, Volume= 0.360 af, Atten= 99%, Lag= 476.5 min
Primary = 0.10 cfs @ 19.90 hrs, Volume= 0.360 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 623.10' @ 19.90 hrs Surf.Area= 9,816 sf Storage= 12,480 cf
Plug-Flow detention time= 1,873.9 min calculated for 0.360 af (97% of inflow)
Center-of-Mass det. time= 1,857.2 min ( 2,686.5 - 829.2 )
Volume Invert Avail.Storage Storage Description
#1 622.00' 45,378 cf Main pool above forebay berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
622.00 7,948 0 0
626.00 14,741 45,378 45,378
Device Routing Invert Outlet Devices
#1 Primary 615.15'15.0" Round Culvert
L= 310.0' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 615.15' / 611.44' S= 0.0120 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 622.00'1.7" Vert. Orifice/Grate C= 0.600
#3 Device 1 623.00'3.0" Vert. Orifice/Grate C= 0.600
#4 Device 1 624.75'16.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 625.50'20.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Primary OutFlow Max=0.10 cfs @ 19.90 hrs HW=623.10' (Free Discharge)
1=Culvert (Passes 0.10 cfs of 10.75 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.08 cfs @ 4.88 fps)
3=Orifice/Grate (Orifice Controls 0.02 cfs @ 1.08 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=622.00' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 28HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 4P: Pond 2
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)9
8
7
6
5
4
3
2
1
0
Inflow Area=3.020 ac
Peak Elev=623.10'
Storage=12,480 cf
8.14 cfs
0.10 cfs
0.10 cfs
0.00 cfs
Pond 4P: Pond 2
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302826242220181614121086420Elevation (feet)626
625
624
623
622
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 30HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 1L: POI 1 COMBINED
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 0.64" for 1yr 24 hour event
Inflow = 13.82 cfs @ 12.13 hrs, Volume= 1.313 af
Primary = 13.82 cfs @ 12.13 hrs, Volume= 1.313 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 1L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=24.780 ac
13.82 cfs
13.82 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 31HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 2L: POI 1 COMBINED
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 1.05" for 1yr 24 hour event
Inflow = 12.92 cfs @ 12.12 hrs, Volume= 2.550 af
Primary = 12.92 cfs @ 12.12 hrs, Volume= 2.550 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 2L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=29.030 ac
12.92 cfs
12.92 cfs
Type II 24-hr 1yr 24 hour Rainfall=2.95"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 32HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 3L: POI 4
Inflow Area = 6.130 ac, 30.34% Impervious, Inflow Depth > 0.88" for 1yr 24 hour event
Inflow = 0.54 cfs @ 12.42 hrs, Volume= 0.450 af
Primary = 0.54 cfs @ 12.42 hrs, Volume= 0.450 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 3L: POI 4
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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
Inflow Area=6.130 ac
0.54 cfs
0.54 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 60HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=17.900 ac 2.79% Impervious Runoff Depth=0.10"Subcatchment 1S: Pre DA 1A
Flow Length=635' Tc=24.0 min CN=59 Runoff=1.12 cfs 0.151 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=1.01"Subcatchment 2S: Pre DA 1B
Tc=18.6 min CN=85 Runoff=9.98 cfs 0.577 af
Runoff Area=7.050 ac 9.65% Impervious Runoff Depth=0.30"Subcatchment 3S: Pre DA 2
Flow Length=1,795' Tc=15.5 min CN=68 Runoff=2.46 cfs 0.174 af
Runoff Area=0.860 ac 17.44% Impervious Runoff Depth=0.22"Subcatchment 4S: Pre DA 3
Flow Length=344' Tc=3.0 min CN=65 Runoff=0.30 cfs 0.016 af
Runoff Area=8.370 ac 2.99% Impervious Runoff Depth=0.10"Subcatchment 5S: Pre DA 4
Flow Length=2,170' Tc=34.6 min CN=59 Runoff=0.47 cfs 0.071 af
Runoff Area=11.320 ac 65.19% Impervious Runoff Depth=1.01"Subcatchment 6S: Post DA 1A Controlled
Tc=5.0 min CN=85 Runoff=25.89 cfs 0.949 af
Runoff Area=10.830 ac 0.00% Impervious Runoff Depth=0.09"Subcatchment 7S: Post DA 1A Sheet Flow
Flow Length=1,286' Tc=28.4 min CN=58 Runoff=0.51 cfs 0.077 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=1.01"Subcatchment 8S: Post DA 1B
Flow Length=340' Tc=18.6 min CN=85 Runoff=9.98 cfs 0.577 af
Runoff Area=3.840 ac 30.21% Impervious Runoff Depth=0.42"Subcatchment 9S: Post DA 2
Flow Length=100' Slope=0.0300 '/' Tc=13.0 min CN=72 Runoff=2.32 cfs 0.134 af
Runoff Area=0.550 ac 50.91% Impervious Runoff Depth=0.74"Subcatchment 10S: Post DA 3
Flow Length=35' Slope=0.0200 '/' Tc=9.0 min CN=80 Runoff=0.78 cfs 0.034 af
Runoff Area=3.020 ac 61.59% Impervious Runoff Depth=0.95"Subcatchment 11S: Post DA 4 Controlled
Tc=5.0 min CN=84 Runoff=6.50 cfs 0.239 af
Runoff Area=3.110 ac 0.00% Impervious Runoff Depth=0.14"Subcatchment 13S: Post DA 4 Sheet Flow
Tc=34.6 min CN=61 Runoff=0.26 cfs 0.035 af
Peak Elev=624.28' Inflow=10.20 cfs 0.727 afPond 1P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=10.20 cfs 0.727 af
Peak Elev=632.51' Storage=38,929 cf Inflow=25.89 cfs 0.949 afPond 2P: Pond 1
Primary=0.24 cfs 0.943 af Secondary=0.00 cfs 0.000 af Outflow=0.24 cfs 0.943 af
Peak Elev=624.28' Inflow=10.20 cfs 1.597 afPond 3P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=10.20 cfs 1.597 af
Peak Elev=622.86' Storage=9,728 cf Inflow=6.50 cfs 0.239 afPond 4P: Pond 2
Primary=0.07 cfs 0.232 af Secondary=0.00 cfs 0.000 af Outflow=0.07 cfs 0.232 af
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 61HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Inflow=10.20 cfs 0.727 afLink 1L: POI 1 COMBINED
Primary=10.20 cfs 0.727 af
Inflow=10.20 cfs 1.597 afLink 2L: POI 1 COMBINED
Primary=10.20 cfs 1.597 af
Inflow=0.32 cfs 0.267 afLink 3L: POI 4
Primary=0.32 cfs 0.267 af
Total Runoff Area = 80.610 ac Runoff Volume = 3.033 af Average Runoff Depth = 0.45"
84.79% Pervious = 68.350 ac 15.21% Impervious = 12.260 ac
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 62HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1A
Runoff = 1.12 cfs @ 3.71 hrs, Volume= 0.151 af, Depth= 0.10"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
17.400 58 Woods/grass comb., Good, HSG B
0.500 98 Paved parking, HSG B
17.900 59 Weighted Average
17.400 97.21% Pervious Area
0.500 2.79% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
9.8 535 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
24.0 635 Total
Subcatchment 1S: Pre DA 1A
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=17.900 ac
Runoff Volume=0.151 af
Runoff Depth=0.10"
Flow Length=635'
Tc=24.0 min
CN=59
1.12 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 63HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 1B
Runoff = 9.98 cfs @ 3.34 hrs, Volume= 0.577 af, Depth= 1.01"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
* 6.880 85 adj prop
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
18.6 Direct Entry,
Subcatchment 2S: Pre DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=6.880 ac
Runoff Volume=0.577 af
Runoff Depth=1.01"
Tc=18.6 min
CN=85
9.98 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 64HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA 2
Runoff = 2.46 cfs @ 3.37 hrs, Volume= 0.174 af, Depth= 0.30"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
* 0.680 98 Impervious
6.370 65 Woods/grass comb., Fair, HSG B
7.050 68 Weighted Average
6.370 90.35% Pervious Area
0.680 9.65% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.1 100 0.0400 0.23 Sheet Flow, Pre Sheet grass
Grass: Short n= 0.150 P2= 3.50"
0.3 35 0.0700 1.85 Shallow Concentrated Flow, Pre Shallow Wooded
Short Grass Pasture Kv= 7.0 fps
8.1 1,660 0.0300 3.40 17.02 Channel Flow, roadside ditch
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
15.5 1,795 Total
Subcatchment 3S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)2
1
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=7.050 ac
Runoff Volume=0.174 af
Runoff Depth=0.30"
Flow Length=1,795'
Tc=15.5 min
CN=68
2.46 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 65HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA 3
[49] Hint: Tc<2dt may require smaller dt
Runoff = 0.30 cfs @ 3.18 hrs, Volume= 0.016 af, Depth= 0.22"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
0.150 98 Paved parking, HSG B
0.710 58 Woods/grass comb., Good, HSG B
0.860 65 Weighted Average
0.710 82.56% Pervious Area
0.150 17.44% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 20 0.4000 0.19 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
1.3 324 0.7000 4.18 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
3.0 344 Total
Subcatchment 4S: Pre DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)0.34
0.32
0.3
0.28
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
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=0.860 ac
Runoff Volume=0.016 af
Runoff Depth=0.22"
Flow Length=344'
Tc=3.0 min
CN=65
0.30 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 66HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Pre DA 4
Runoff = 0.47 cfs @ 3.89 hrs, Volume= 0.071 af, Depth= 0.10"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
8.120 58 Woods/grass comb., Good, HSG B
8.370 59 Weighted Average
8.120 97.01% Pervious Area
0.250 2.99% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
10.0 670 0.0500 1.12 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
10.4 1,400 0.0130 2.24 11.21 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
34.6 2,170 Total
Subcatchment 5S: Pre DA 4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)0.52
0.5
0.48
0.46
0.44
0.42
0.4
0.38
0.36
0.34
0.32
0.3
0.28
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
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=8.370 ac
Runoff Volume=0.071 af
Runoff Depth=0.10"
Flow Length=2,170'
Tc=34.6 min
CN=59
0.47 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 67HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA 1A Controlled
Runoff = 25.89 cfs @ 3.16 hrs, Volume= 0.949 af, Depth= 1.01"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
7.380 98 Paved parking, HSG B
3.940 61 >75% Grass cover, Good, HSG B
11.320 85 Weighted Average
3.940 34.81% Pervious Area
7.380 65.19% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 6S: Post DA 1A Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=11.320 ac
Runoff Volume=0.949 af
Runoff Depth=1.01"
Tc=5.0 min
CN=85
25.89 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 68HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA 1A Sheet Flow
Runoff = 0.51 cfs @ 3.83 hrs, Volume= 0.077 af, Depth= 0.09"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
10.830 58 Woods/grass comb., Good, HSG B
10.830 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
17.5 100 0.0300 0.10 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
6.8 500 0.0600 1.22 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
4.1 686 0.0200 2.78 13.90 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
28.4 1,286 Total
Subcatchment 7S: Post DA 1A Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=10.830 ac
Runoff Volume=0.077 af
Runoff Depth=0.09"
Flow Length=1,286'
Tc=28.4 min
CN=58
0.51 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 69HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA 1B
Runoff = 9.98 cfs @ 3.34 hrs, Volume= 0.577 af, Depth= 1.01"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
* 6.880 85 Adjacent Developed Property
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
4.4 240 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
18.6 340 Total
Subcatchment 8S: Post DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=6.880 ac
Runoff Volume=0.577 af
Runoff Depth=1.01"
Flow Length=340'
Tc=18.6 min
CN=85
9.98 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 70HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 9S: Post DA 2
Runoff = 2.32 cfs @ 3.30 hrs, Volume= 0.134 af, Depth= 0.42"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
1.160 98 Paved parking, HSG B
2.680 61 >75% Grass cover, Good, HSG B
3.840 72 Weighted Average
2.680 69.79% Pervious Area
1.160 30.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
8.0 100 0.0300 0.21 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
13.0 100 Total
Subcatchment 9S: Post DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)2
1
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=3.840 ac
Runoff Volume=0.134 af
Runoff Depth=0.42"
Flow Length=100'
Slope=0.0300 '/'
Tc=13.0 min
CN=72
2.32 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 71HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 10S: Post DA 3
Runoff = 0.78 cfs @ 3.22 hrs, Volume= 0.034 af, Depth= 0.74"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
0.280 98 Paved parking, HSG B
0.270 61 >75% Grass cover, Good, HSG B
0.550 80 Weighted Average
0.270 49.09% Pervious Area
0.280 50.91% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
4.0 35 0.0200 0.14 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
9.0 35 Total
Subcatchment 10S: Post DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=0.550 ac
Runoff Volume=0.034 af
Runoff Depth=0.74"
Flow Length=35'
Slope=0.0200 '/'
Tc=9.0 min
CN=80
0.78 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 72HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 11S: Post DA 4 Controlled
Runoff = 6.50 cfs @ 3.16 hrs, Volume= 0.239 af, Depth= 0.95"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
1.860 98 Paved parking, HSG B
1.160 61 >75% Grass cover, Good, HSG B
3.020 84 Weighted Average
1.160 38.41% Pervious Area
1.860 61.59% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 11S: Post DA 4 Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)7
6
5
4
3
2
1
0
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=3.020 ac
Runoff Volume=0.239 af
Runoff Depth=0.95"
Tc=5.0 min
CN=84
6.50 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 73HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 13S: Post DA 4 Sheet Flow
Runoff = 0.26 cfs @ 3.81 hrs, Volume= 0.035 af, Depth= 0.14"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"
Area (ac) CN Description
* 3.110 61 >75% Grass cover, Good, HSG B
3.110 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
34.6 Direct Entry,
Subcatchment 13S: Post DA 4 Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)0.28
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
Charlotte 6-hr
2-yr
6hr - 2yr Rainfall=2.28"
Runoff Area=3.110 ac
Runoff Volume=0.035 af
Runoff Depth=0.14"
Tc=34.6 min
CN=61
0.26 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 74HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 1P: DS 24" Culvert
[57] Hint: Peaked at 624.28' (Flood elevation advised)
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 0.35" for 6hr - 2yr event
Inflow = 10.20 cfs @ 3.35 hrs, Volume= 0.727 af
Outflow = 10.20 cfs @ 3.35 hrs, Volume= 0.727 af, Atten= 0%, Lag= 0.0 min
Primary = 10.20 cfs @ 3.35 hrs, Volume= 0.727 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 624.28' @ 3.35 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=10.15 cfs @ 3.35 hrs HW=624.28' (Free Discharge)
1=Culvert (Barrel Controls 10.15 cfs @ 5.74 fps)
Pond 1P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=24.780 ac
Peak Elev=624.28'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
10.20 cfs
10.20 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 76HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 2P: Pond 1
Inflow Area = 11.320 ac, 65.19% Impervious, Inflow Depth = 1.01" for 6hr - 2yr event
Inflow = 25.89 cfs @ 3.16 hrs, Volume= 0.949 af
Outflow = 0.24 cfs @ 6.09 hrs, Volume= 0.943 af, Atten= 99%, Lag= 176.0 min
Primary = 0.24 cfs @ 6.09 hrs, Volume= 0.943 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 632.51' @ 6.09 hrs Surf.Area= 35,098 sf Storage= 38,929 cf
Plug-Flow detention time= 1,868.2 min calculated for 0.943 af (99% of inflow)
Center-of-Mass det. time= 1,869.0 min ( 2,085.9 - 216.9 )
Volume Invert Avail.Storage Storage Description
#1 631.50' 173,626 cf Main Pool Above Forebay Berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.50 32,265 0 0
636.00 44,902 173,626 173,626
Device Routing Invert Outlet Devices
#1 Primary 630.50'18.0" Round Culvert
L= 400.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 630.50' / 625.50' S= 0.0125 '/' Cc= 0.900
n= 0.013 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 631.50'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 633.00'12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 635.00'16.0' long Sharp-Crested Rectangular Weir 0 End Contraction(s)
#5 Secondary 635.50'20.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.24 cfs @ 6.09 hrs HW=632.51' (Free Discharge)
1=Culvert (Passes 0.24 cfs of 11.41 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.24 cfs @ 4.84 fps)
3=Orifice/Grate ( Controls 0.00 cfs)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.50' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 77HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 2P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=11.320 ac
Peak Elev=632.51'
Storage=38,929 cf
25.89 cfs
0.24 cfs
0.24 cfs
0.00 cfs
Pond 2P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302520151050Elevation (feet)636
635
634
633
632
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 79HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 3P: DS 24" Culvert
[57] Hint: Peaked at 624.28' (Flood elevation advised)
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 0.66" for 6hr - 2yr event
Inflow = 10.20 cfs @ 3.34 hrs, Volume= 1.597 af
Outflow = 10.20 cfs @ 3.34 hrs, Volume= 1.597 af, Atten= 0%, Lag= 0.0 min
Primary = 10.20 cfs @ 3.34 hrs, Volume= 1.597 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 624.28' @ 3.34 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=10.13 cfs @ 3.34 hrs HW=624.27' (Free Discharge)
1=Culvert (Barrel Controls 10.13 cfs @ 5.73 fps)
Pond 3P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=29.030 ac
Peak Elev=624.28'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
10.20 cfs
10.20 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 81HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 4P: Pond 2
Inflow Area = 3.020 ac, 61.59% Impervious, Inflow Depth = 0.95" for 6hr - 2yr event
Inflow = 6.50 cfs @ 3.16 hrs, Volume= 0.239 af
Outflow = 0.07 cfs @ 6.09 hrs, Volume= 0.232 af, Atten= 99%, Lag= 175.7 min
Primary = 0.07 cfs @ 6.09 hrs, Volume= 0.232 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 622.86' @ 6.09 hrs Surf.Area= 9,404 sf Storage= 9,728 cf
Plug-Flow detention time= 1,710.6 min calculated for 0.232 af (97% of inflow)
Center-of-Mass det. time= 1,706.7 min ( 1,924.6 - 217.9 )
Volume Invert Avail.Storage Storage Description
#1 622.00' 45,378 cf Main pool above forebay berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
622.00 7,948 0 0
626.00 14,741 45,378 45,378
Device Routing Invert Outlet Devices
#1 Primary 615.15'15.0" Round Culvert
L= 310.0' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 615.15' / 611.44' S= 0.0120 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 622.00'1.7" Vert. Orifice/Grate C= 0.600
#3 Device 1 623.00'3.0" Vert. Orifice/Grate C= 0.600
#4 Device 1 624.75'16.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 625.50'20.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Primary OutFlow Max=0.07 cfs @ 6.09 hrs HW=622.86' (Free Discharge)
1=Culvert (Passes 0.07 cfs of 10.63 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.07 cfs @ 4.27 fps)
3=Orifice/Grate ( Controls 0.00 cfs)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=622.00' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 82HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 4P: Pond 2
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)7
6
5
4
3
2
1
0
Inflow Area=3.020 ac
Peak Elev=622.86'
Storage=9,728 cf
6.50 cfs
0.07 cfs
0.07 cfs
0.00 cfs
Pond 4P: Pond 2
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302826242220181614121086420Elevation (feet)626
625
624
623
622
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 84HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 1L: POI 1 COMBINED
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 0.35" for 6hr - 2yr event
Inflow = 10.20 cfs @ 3.35 hrs, Volume= 0.727 af
Primary = 10.20 cfs @ 3.35 hrs, Volume= 0.727 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 1L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=24.780 ac
10.20 cfs
10.20 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 85HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 2L: POI 1 COMBINED
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 0.66" for 6hr - 2yr event
Inflow = 10.20 cfs @ 3.34 hrs, Volume= 1.597 af
Primary = 10.20 cfs @ 3.34 hrs, Volume= 1.597 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 2L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=29.030 ac
10.20 cfs
10.20 cfs
Charlotte 6-hr 2-yr 6hr - 2yr Rainfall=2.28"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 86HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 3L: POI 4
Inflow Area = 6.130 ac, 30.34% Impervious, Inflow Depth > 0.52" for 6hr - 2yr event
Inflow = 0.32 cfs @ 3.81 hrs, Volume= 0.267 af
Primary = 0.32 cfs @ 3.81 hrs, Volume= 0.267 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 3L: POI 4
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)0.34
0.32
0.3
0.28
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
Inflow Area=6.130 ac
0.32 cfs
0.32 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 87HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=17.900 ac 2.79% Impervious Runoff Depth=1.19"Subcatchment 1S: Pre DA 1A
Flow Length=635' Tc=24.0 min CN=59 Runoff=22.75 cfs 1.774 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=3.29"Subcatchment 2S: Pre DA 1B
Tc=18.6 min CN=85 Runoff=29.83 cfs 1.889 af
Runoff Area=7.050 ac 9.65% Impervious Runoff Depth=1.82"Subcatchment 3S: Pre DA 2
Flow Length=1,795' Tc=15.5 min CN=68 Runoff=18.00 cfs 1.071 af
Runoff Area=0.860 ac 17.44% Impervious Runoff Depth=1.60"Subcatchment 4S: Pre DA 3
Flow Length=344' Tc=3.0 min CN=65 Runoff=2.79 cfs 0.115 af
Runoff Area=8.370 ac 2.99% Impervious Runoff Depth=1.19"Subcatchment 5S: Pre DA 4
Flow Length=2,170' Tc=34.6 min CN=59 Runoff=8.74 cfs 0.829 af
Runoff Area=11.320 ac 65.19% Impervious Runoff Depth=3.29"Subcatchment 6S: Post DA 1A Controlled
Tc=5.0 min CN=85 Runoff=70.96 cfs 3.108 af
Runoff Area=10.830 ac 0.00% Impervious Runoff Depth=1.13"Subcatchment 7S: Post DA 1A Sheet Flow
Flow Length=1,286' Tc=28.4 min CN=58 Runoff=11.78 cfs 1.015 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=3.29"Subcatchment 8S: Post DA 1B
Flow Length=340' Tc=18.6 min CN=85 Runoff=29.83 cfs 1.889 af
Runoff Area=3.840 ac 30.21% Impervious Runoff Depth=2.14"Subcatchment 9S: Post DA 2
Flow Length=100' Slope=0.0300 '/' Tc=13.0 min CN=72 Runoff=12.45 cfs 0.684 af
Runoff Area=0.550 ac 50.91% Impervious Runoff Depth=2.82"Subcatchment 10S: Post DA 3
Flow Length=35' Slope=0.0200 '/' Tc=9.0 min CN=80 Runoff=2.66 cfs 0.129 af
Runoff Area=3.020 ac 61.59% Impervious Runoff Depth=3.20"Subcatchment 11S: Post DA 4 Controlled
Tc=5.0 min CN=84 Runoff=18.46 cfs 0.805 af
Runoff Area=3.110 ac 0.00% Impervious Runoff Depth=1.32"Subcatchment 13S: Post DA 4 Sheet Flow
Tc=34.6 min CN=61 Runoff=3.68 cfs 0.342 af
Peak Elev=631.66' Inflow=49.32 cfs 3.663 afPond 1P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=49.32 cfs 3.663 af
Peak Elev=634.32' Storage=108,991 cf Inflow=70.96 cfs 3.108 afPond 2P: Pond 1
Primary=2.89 cfs 3.078 af Secondary=0.00 cfs 0.000 af Outflow=2.89 cfs 3.078 af
Peak Elev=628.99' Inflow=39.49 cfs 5.982 afPond 3P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=39.49 cfs 5.982 af
Peak Elev=624.72' Storage=30,855 cf Inflow=18.46 cfs 0.805 afPond 4P: Pond 2
Primary=0.42 cfs 0.793 af Secondary=0.00 cfs 0.000 af Outflow=0.42 cfs 0.793 af
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 88HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Inflow=49.32 cfs 3.663 afLink 1L: POI 1 COMBINED
Primary=49.32 cfs 3.663 af
Inflow=39.49 cfs 5.982 afLink 2L: POI 1 COMBINED
Primary=39.49 cfs 5.982 af
Inflow=4.04 cfs 1.135 afLink 3L: POI 4
Primary=4.04 cfs 1.135 af
Total Runoff Area = 80.610 ac Runoff Volume = 13.649 af Average Runoff Depth = 2.03"
84.79% Pervious = 68.350 ac 15.21% Impervious = 12.260 ac
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 89HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1A
Runoff = 22.75 cfs @ 3.46 hrs, Volume= 1.774 af, Depth= 1.19"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
17.400 58 Woods/grass comb., Good, HSG B
0.500 98 Paved parking, HSG B
17.900 59 Weighted Average
17.400 97.21% Pervious Area
0.500 2.79% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
9.8 535 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
24.0 635 Total
Subcatchment 1S: Pre DA 1A
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=17.900 ac
Runoff Volume=1.774 af
Runoff Depth=1.19"
Flow Length=635'
Tc=24.0 min
CN=59
22.75 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 90HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 1B
Runoff = 29.83 cfs @ 3.33 hrs, Volume= 1.889 af, Depth= 3.29"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
* 6.880 85 adj prop
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
18.6 Direct Entry,
Subcatchment 2S: Pre DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=6.880 ac
Runoff Volume=1.889 af
Runoff Depth=3.29"
Tc=18.6 min
CN=85
29.83 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 91HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA 2
Runoff = 18.00 cfs @ 3.31 hrs, Volume= 1.071 af, Depth= 1.82"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
* 0.680 98 Impervious
6.370 65 Woods/grass comb., Fair, HSG B
7.050 68 Weighted Average
6.370 90.35% Pervious Area
0.680 9.65% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.1 100 0.0400 0.23 Sheet Flow, Pre Sheet grass
Grass: Short n= 0.150 P2= 3.50"
0.3 35 0.0700 1.85 Shallow Concentrated Flow, Pre Shallow Wooded
Short Grass Pasture Kv= 7.0 fps
8.1 1,660 0.0300 3.40 17.02 Channel Flow, roadside ditch
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
15.5 1,795 Total
Subcatchment 3S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=7.050 ac
Runoff Volume=1.071 af
Runoff Depth=1.82"
Flow Length=1,795'
Tc=15.5 min
CN=68
18.00 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 92HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA 3
[49] Hint: Tc<2dt may require smaller dt
Runoff = 2.79 cfs @ 3.14 hrs, Volume= 0.115 af, Depth= 1.60"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
0.150 98 Paved parking, HSG B
0.710 58 Woods/grass comb., Good, HSG B
0.860 65 Weighted Average
0.710 82.56% Pervious Area
0.150 17.44% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 20 0.4000 0.19 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
1.3 324 0.7000 4.18 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
3.0 344 Total
Subcatchment 4S: Pre DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=0.860 ac
Runoff Volume=0.115 af
Runoff Depth=1.60"
Flow Length=344'
Tc=3.0 min
CN=65
2.79 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 93HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Pre DA 4
Runoff = 8.74 cfs @ 3.62 hrs, Volume= 0.829 af, Depth= 1.19"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
8.120 58 Woods/grass comb., Good, HSG B
8.370 59 Weighted Average
8.120 97.01% Pervious Area
0.250 2.99% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
10.0 670 0.0500 1.12 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
10.4 1,400 0.0130 2.24 11.21 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
34.6 2,170 Total
Subcatchment 5S: Pre DA 4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=8.370 ac
Runoff Volume=0.829 af
Runoff Depth=1.19"
Flow Length=2,170'
Tc=34.6 min
CN=59
8.74 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 94HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA 1A Controlled
Runoff = 70.96 cfs @ 3.15 hrs, Volume= 3.108 af, Depth= 3.29"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
7.380 98 Paved parking, HSG B
3.940 61 >75% Grass cover, Good, HSG B
11.320 85 Weighted Average
3.940 34.81% Pervious Area
7.380 65.19% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 6S: Post DA 1A Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=11.320 ac
Runoff Volume=3.108 af
Runoff Depth=3.29"
Tc=5.0 min
CN=85
70.96 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 95HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA 1A Sheet Flow
Runoff = 11.78 cfs @ 3.53 hrs, Volume= 1.015 af, Depth= 1.13"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
10.830 58 Woods/grass comb., Good, HSG B
10.830 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
17.5 100 0.0300 0.10 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
6.8 500 0.0600 1.22 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
4.1 686 0.0200 2.78 13.90 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
28.4 1,286 Total
Subcatchment 7S: Post DA 1A Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=10.830 ac
Runoff Volume=1.015 af
Runoff Depth=1.13"
Flow Length=1,286'
Tc=28.4 min
CN=58
11.78 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 96HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA 1B
Runoff = 29.83 cfs @ 3.33 hrs, Volume= 1.889 af, Depth= 3.29"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
* 6.880 85 Adjacent Developed Property
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
4.4 240 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
18.6 340 Total
Subcatchment 8S: Post DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=6.880 ac
Runoff Volume=1.889 af
Runoff Depth=3.29"
Flow Length=340'
Tc=18.6 min
CN=85
29.83 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 97HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 9S: Post DA 2
Runoff = 12.45 cfs @ 3.27 hrs, Volume= 0.684 af, Depth= 2.14"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
1.160 98 Paved parking, HSG B
2.680 61 >75% Grass cover, Good, HSG B
3.840 72 Weighted Average
2.680 69.79% Pervious Area
1.160 30.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
8.0 100 0.0300 0.21 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
13.0 100 Total
Subcatchment 9S: Post DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=3.840 ac
Runoff Volume=0.684 af
Runoff Depth=2.14"
Flow Length=100'
Slope=0.0300 '/'
Tc=13.0 min
CN=72
12.45 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 98HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 10S: Post DA 3
Runoff = 2.66 cfs @ 3.21 hrs, Volume= 0.129 af, Depth= 2.82"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
0.280 98 Paved parking, HSG B
0.270 61 >75% Grass cover, Good, HSG B
0.550 80 Weighted Average
0.270 49.09% Pervious Area
0.280 50.91% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
4.0 35 0.0200 0.14 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
9.0 35 Total
Subcatchment 10S: Post DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=0.550 ac
Runoff Volume=0.129 af
Runoff Depth=2.82"
Flow Length=35'
Slope=0.0200 '/'
Tc=9.0 min
CN=80
2.66 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 99HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 11S: Post DA 4 Controlled
Runoff = 18.46 cfs @ 3.15 hrs, Volume= 0.805 af, Depth= 3.20"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
1.860 98 Paved parking, HSG B
1.160 61 >75% Grass cover, Good, HSG B
3.020 84 Weighted Average
1.160 38.41% Pervious Area
1.860 61.59% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 11S: Post DA 4 Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=3.020 ac
Runoff Volume=0.805 af
Runoff Depth=3.20"
Tc=5.0 min
CN=84
18.46 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 100HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 13S: Post DA 4 Sheet Flow
Runoff = 3.68 cfs @ 3.61 hrs, Volume= 0.342 af, Depth= 1.32"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"
Area (ac) CN Description
* 3.110 61 >75% Grass cover, Good, HSG B
3.110 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
34.6 Direct Entry,
Subcatchment 13S: Post DA 4 Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)4
3
2
1
0
Charlotte 6-hr 50-yr
6hr - 50yr Rainfall=4.92"
Runoff Area=3.110 ac
Runoff Volume=0.342 af
Runoff Depth=1.32"
Tc=34.6 min
CN=61
3.68 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 101HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 1P: DS 24" Culvert
[57] Hint: Peaked at 631.66' (Flood elevation advised)
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 1.77" for 6hr - 50yr event
Inflow = 49.32 cfs @ 3.38 hrs, Volume= 3.663 af
Outflow = 49.32 cfs @ 3.38 hrs, Volume= 3.663 af, Atten= 0%, Lag= 0.0 min
Primary = 49.32 cfs @ 3.38 hrs, Volume= 3.663 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 631.66' @ 3.38 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=49.04 cfs @ 3.38 hrs HW=631.58' (Free Discharge)
1=Culvert (Barrel Controls 49.04 cfs @ 15.61 fps)
Pond 1P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=24.780 ac
Peak Elev=631.66'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
49.32 cfs
49.32 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 103HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 2P: Pond 1
Inflow Area = 11.320 ac, 65.19% Impervious, Inflow Depth = 3.29" for 6hr - 50yr event
Inflow = 70.96 cfs @ 3.15 hrs, Volume= 3.108 af
Outflow = 2.89 cfs @ 4.99 hrs, Volume= 3.078 af, Atten= 96%, Lag= 110.6 min
Primary = 2.89 cfs @ 4.99 hrs, Volume= 3.078 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 634.32' @ 4.99 hrs Surf.Area= 40,198 sf Storage= 108,991 cf
Plug-Flow detention time= 1,448.7 min calculated for 3.078 af (99% of inflow)
Center-of-Mass det. time= 1,447.3 min ( 1,656.1 - 208.8 )
Volume Invert Avail.Storage Storage Description
#1 631.50' 173,626 cf Main Pool Above Forebay Berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.50 32,265 0 0
636.00 44,902 173,626 173,626
Device Routing Invert Outlet Devices
#1 Primary 630.50'18.0" Round Culvert
L= 400.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 630.50' / 625.50' S= 0.0125 '/' Cc= 0.900
n= 0.013 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 631.50'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 633.00'12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 635.00'16.0' long Sharp-Crested Rectangular Weir 0 End Contraction(s)
#5 Secondary 635.50'20.0' 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=2.89 cfs @ 4.99 hrs HW=634.32' (Free Discharge)
1=Culvert (Passes 2.89 cfs of 13.15 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.40 cfs @ 8.09 fps)
3=Orifice/Grate (Orifice Controls 2.49 cfs @ 4.98 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.50' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 104HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 2P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=11.320 ac
Peak Elev=634.32'
Storage=108,991 cf
70.96 cfs
2.89 cfs
2.89 cfs
0.00 cfs
Pond 2P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302520151050Elevation (feet)636
635
634
633
632
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 106HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 3P: DS 24" Culvert
[57] Hint: Peaked at 628.99' (Flood elevation advised)
[79] Warning: Submerged Pond 2P Primary device # 1 OUTLET by 3.47'
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 2.47" for 6hr - 50yr event
Inflow = 39.49 cfs @ 3.37 hrs, Volume= 5.982 af
Outflow = 39.49 cfs @ 3.37 hrs, Volume= 5.982 af, Atten= 0%, Lag= 0.0 min
Primary = 39.49 cfs @ 3.37 hrs, Volume= 5.982 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 628.99' @ 3.37 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=39.33 cfs @ 3.37 hrs HW=628.95' (Free Discharge)
1=Culvert (Barrel Controls 39.33 cfs @ 12.52 fps)
Pond 3P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=29.030 ac
Peak Elev=628.99'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
39.49 cfs
39.49 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 108HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 4P: Pond 2
Inflow Area = 3.020 ac, 61.59% Impervious, Inflow Depth = 3.20" for 6hr - 50yr event
Inflow = 18.46 cfs @ 3.15 hrs, Volume= 0.805 af
Outflow = 0.42 cfs @ 6.04 hrs, Volume= 0.793 af, Atten= 98%, Lag= 173.2 min
Primary = 0.42 cfs @ 6.04 hrs, Volume= 0.793 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 624.72' @ 6.04 hrs Surf.Area= 12,567 sf Storage= 30,855 cf
Plug-Flow detention time= 1,395.5 min calculated for 0.792 af (98% of inflow)
Center-of-Mass det. time= 1,395.1 min ( 1,604.7 - 209.6 )
Volume Invert Avail.Storage Storage Description
#1 622.00' 45,378 cf Main pool above forebay berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
622.00 7,948 0 0
626.00 14,741 45,378 45,378
Device Routing Invert Outlet Devices
#1 Primary 615.15'15.0" Round Culvert
L= 310.0' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 615.15' / 611.44' S= 0.0120 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 622.00'1.7" Vert. Orifice/Grate C= 0.600
#3 Device 1 623.00'3.0" Vert. Orifice/Grate C= 0.600
#4 Device 1 624.75'16.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 625.50'20.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Primary OutFlow Max=0.42 cfs @ 6.04 hrs HW=624.72' (Free Discharge)
1=Culvert (Passes 0.42 cfs of 11.56 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.12 cfs @ 7.84 fps)
3=Orifice/Grate (Orifice Controls 0.30 cfs @ 6.08 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=622.00' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 109HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 4P: Pond 2
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=3.020 ac
Peak Elev=624.72'
Storage=30,855 cf
18.46 cfs
0.42 cfs
0.42 cfs
0.00 cfs
Pond 4P: Pond 2
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302826242220181614121086420Elevation (feet)626
625
624
623
622
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 111HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 1L: POI 1 COMBINED
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 1.77" for 6hr - 50yr event
Inflow = 49.32 cfs @ 3.38 hrs, Volume= 3.663 af
Primary = 49.32 cfs @ 3.38 hrs, Volume= 3.663 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 1L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=24.780 ac
49.32 cfs
49.32 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 112HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 2L: POI 1 COMBINED
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 2.47" for 6hr - 50yr event
Inflow = 39.49 cfs @ 3.37 hrs, Volume= 5.982 af
Primary = 39.49 cfs @ 3.37 hrs, Volume= 5.982 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 2L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=29.030 ac
39.49 cfs
39.49 cfs
Charlotte 6-hr 50-yr 6hr - 50yr Rainfall=4.92"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 113HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 3L: POI 4
Inflow Area = 6.130 ac, 30.34% Impervious, Inflow Depth > 2.22" for 6hr - 50yr event
Inflow = 4.04 cfs @ 3.61 hrs, Volume= 1.135 af
Primary = 4.04 cfs @ 3.61 hrs, Volume= 1.135 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 3L: POI 4
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)4
3
2
1
0
Inflow Area=6.130 ac
4.04 cfs
4.04 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 33HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=17.900 ac 2.79% Impervious Runoff Depth=0.59"Subcatchment 1S: Pre DA 1A
Flow Length=635' Tc=24.0 min CN=59 Runoff=10.33 cfs 0.873 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=2.21"Subcatchment 2S: Pre DA 1B
Tc=18.6 min CN=85 Runoff=20.78 cfs 1.267 af
Runoff Area=7.050 ac 9.65% Impervious Runoff Depth=1.03"Subcatchment 3S: Pre DA 2
Flow Length=1,795' Tc=15.5 min CN=68 Runoff=10.11 cfs 0.606 af
Runoff Area=0.860 ac 17.44% Impervious Runoff Depth=0.87"Subcatchment 4S: Pre DA 3
Flow Length=344' Tc=3.0 min CN=65 Runoff=1.49 cfs 0.062 af
Runoff Area=8.370 ac 2.99% Impervious Runoff Depth=0.59"Subcatchment 5S: Pre DA 4
Flow Length=2,170' Tc=34.6 min CN=59 Runoff=4.02 cfs 0.408 af
Runoff Area=11.320 ac 65.19% Impervious Runoff Depth=2.21"Subcatchment 6S: Post DA 1A Controlled
Tc=5.0 min CN=85 Runoff=50.08 cfs 2.084 af
Runoff Area=10.830 ac 0.00% Impervious Runoff Depth=0.54"Subcatchment 7S: Post DA 1A Sheet Flow
Flow Length=1,286' Tc=28.4 min CN=58 Runoff=5.22 cfs 0.490 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=2.21"Subcatchment 8S: Post DA 1B
Flow Length=340' Tc=18.6 min CN=85 Runoff=20.78 cfs 1.267 af
Runoff Area=3.840 ac 30.21% Impervious Runoff Depth=1.27"Subcatchment 9S: Post DA 2
Flow Length=100' Slope=0.0300 '/' Tc=13.0 min CN=72 Runoff=7.47 cfs 0.406 af
Runoff Area=0.550 ac 50.91% Impervious Runoff Depth=1.81"Subcatchment 10S: Post DA 3
Flow Length=35' Slope=0.0200 '/' Tc=9.0 min CN=80 Runoff=1.78 cfs 0.083 af
Runoff Area=3.020 ac 61.59% Impervious Runoff Depth=2.13"Subcatchment 11S: Post DA 4 Controlled
Tc=5.0 min CN=84 Runoff=12.90 cfs 0.535 af
Runoff Area=3.110 ac 0.00% Impervious Runoff Depth=0.67"Subcatchment 13S: Post DA 4 Sheet Flow
Tc=34.6 min CN=61 Runoff=1.78 cfs 0.175 af
Peak Elev=626.69' Inflow=28.42 cfs 2.139 afPond 1P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=28.42 cfs 2.139 af
Peak Elev=633.53' Storage=78,172 cf Inflow=50.08 cfs 2.084 afPond 2P: Pond 1
Primary=1.55 cfs 2.060 af Secondary=0.00 cfs 0.000 af Outflow=1.55 cfs 2.060 af
Peak Elev=625.93' Inflow=23.67 cfs 3.816 afPond 3P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=23.67 cfs 3.816 af
Peak Elev=623.81' Storage=20,526 cf Inflow=12.90 cfs 0.535 afPond 4P: Pond 2
Primary=0.30 cfs 0.525 af Secondary=0.00 cfs 0.000 af Outflow=0.30 cfs 0.525 af
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 34HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Inflow=28.42 cfs 2.139 afLink 1L: POI 1 COMBINED
Primary=28.42 cfs 2.139 af
Inflow=23.67 cfs 3.816 afLink 2L: POI 1 COMBINED
Primary=23.67 cfs 3.816 af
Inflow=2.01 cfs 0.700 afLink 3L: POI 4
Primary=2.01 cfs 0.700 af
Total Runoff Area = 80.610 ac Runoff Volume = 8.255 af Average Runoff Depth = 1.23"
84.79% Pervious = 68.350 ac 15.21% Impervious = 12.260 ac
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 35HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1A
Runoff = 10.33 cfs @ 3.50 hrs, Volume= 0.873 af, Depth= 0.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
17.400 58 Woods/grass comb., Good, HSG B
0.500 98 Paved parking, HSG B
17.900 59 Weighted Average
17.400 97.21% Pervious Area
0.500 2.79% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
9.8 535 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
24.0 635 Total
Subcatchment 1S: Pre DA 1A
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=17.900 ac
Runoff Volume=0.873 af
Runoff Depth=0.59"
Flow Length=635'
Tc=24.0 min
CN=59
10.33 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 36HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 1B
Runoff = 20.78 cfs @ 3.33 hrs, Volume= 1.267 af, Depth= 2.21"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
* 6.880 85 adj prop
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
18.6 Direct Entry,
Subcatchment 2S: Pre DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=6.880 ac
Runoff Volume=1.267 af
Runoff Depth=2.21"
Tc=18.6 min
CN=85
20.78 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 37HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA 2
Runoff = 10.11 cfs @ 3.32 hrs, Volume= 0.606 af, Depth= 1.03"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
* 0.680 98 Impervious
6.370 65 Woods/grass comb., Fair, HSG B
7.050 68 Weighted Average
6.370 90.35% Pervious Area
0.680 9.65% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.1 100 0.0400 0.23 Sheet Flow, Pre Sheet grass
Grass: Short n= 0.150 P2= 3.50"
0.3 35 0.0700 1.85 Shallow Concentrated Flow, Pre Shallow Wooded
Short Grass Pasture Kv= 7.0 fps
8.1 1,660 0.0300 3.40 17.02 Channel Flow, roadside ditch
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
15.5 1,795 Total
Subcatchment 3S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=7.050 ac
Runoff Volume=0.606 af
Runoff Depth=1.03"
Flow Length=1,795'
Tc=15.5 min
CN=68
10.11 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 38HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA 3
[49] Hint: Tc<2dt may require smaller dt
Runoff = 1.49 cfs @ 3.15 hrs, Volume= 0.062 af, Depth= 0.87"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
0.150 98 Paved parking, HSG B
0.710 58 Woods/grass comb., Good, HSG B
0.860 65 Weighted Average
0.710 82.56% Pervious Area
0.150 17.44% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 20 0.4000 0.19 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
1.3 324 0.7000 4.18 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
3.0 344 Total
Subcatchment 4S: Pre DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=0.860 ac
Runoff Volume=0.062 af
Runoff Depth=0.87"
Flow Length=344'
Tc=3.0 min
CN=65
1.49 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 39HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Pre DA 4
Runoff = 4.02 cfs @ 3.67 hrs, Volume= 0.408 af, Depth= 0.59"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
8.120 58 Woods/grass comb., Good, HSG B
8.370 59 Weighted Average
8.120 97.01% Pervious Area
0.250 2.99% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
10.0 670 0.0500 1.12 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
10.4 1,400 0.0130 2.24 11.21 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
34.6 2,170 Total
Subcatchment 5S: Pre DA 4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)4
3
2
1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=8.370 ac
Runoff Volume=0.408 af
Runoff Depth=0.59"
Flow Length=2,170'
Tc=34.6 min
CN=59
4.02 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 40HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA 1A Controlled
Runoff = 50.08 cfs @ 3.15 hrs, Volume= 2.084 af, Depth= 2.21"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
7.380 98 Paved parking, HSG B
3.940 61 >75% Grass cover, Good, HSG B
11.320 85 Weighted Average
3.940 34.81% Pervious Area
7.380 65.19% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 6S: Post DA 1A Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)55
50
45
40
35
30
25
20
15
10
5
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=11.320 ac
Runoff Volume=2.084 af
Runoff Depth=2.21"
Tc=5.0 min
CN=85
50.08 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 41HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA 1A Sheet Flow
Runoff = 5.22 cfs @ 3.58 hrs, Volume= 0.490 af, Depth= 0.54"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
10.830 58 Woods/grass comb., Good, HSG B
10.830 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
17.5 100 0.0300 0.10 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
6.8 500 0.0600 1.22 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
4.1 686 0.0200 2.78 13.90 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
28.4 1,286 Total
Subcatchment 7S: Post DA 1A Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)5
4
3
2
1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=10.830 ac
Runoff Volume=0.490 af
Runoff Depth=0.54"
Flow Length=1,286'
Tc=28.4 min
CN=58
5.22 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 42HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA 1B
Runoff = 20.78 cfs @ 3.33 hrs, Volume= 1.267 af, Depth= 2.21"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
* 6.880 85 Adjacent Developed Property
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
4.4 240 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
18.6 340 Total
Subcatchment 8S: Post DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=6.880 ac
Runoff Volume=1.267 af
Runoff Depth=2.21"
Flow Length=340'
Tc=18.6 min
CN=85
20.78 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 43HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 9S: Post DA 2
Runoff = 7.47 cfs @ 3.28 hrs, Volume= 0.406 af, Depth= 1.27"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
1.160 98 Paved parking, HSG B
2.680 61 >75% Grass cover, Good, HSG B
3.840 72 Weighted Average
2.680 69.79% Pervious Area
1.160 30.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
8.0 100 0.0300 0.21 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
13.0 100 Total
Subcatchment 9S: Post DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)8
7
6
5
4
3
2
1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=3.840 ac
Runoff Volume=0.406 af
Runoff Depth=1.27"
Flow Length=100'
Slope=0.0300 '/'
Tc=13.0 min
CN=72
7.47 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 44HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 10S: Post DA 3
Runoff = 1.78 cfs @ 3.21 hrs, Volume= 0.083 af, Depth= 1.81"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
0.280 98 Paved parking, HSG B
0.270 61 >75% Grass cover, Good, HSG B
0.550 80 Weighted Average
0.270 49.09% Pervious Area
0.280 50.91% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
4.0 35 0.0200 0.14 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
9.0 35 Total
Subcatchment 10S: Post DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=0.550 ac
Runoff Volume=0.083 af
Runoff Depth=1.81"
Flow Length=35'
Slope=0.0200 '/'
Tc=9.0 min
CN=80
1.78 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 45HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 11S: Post DA 4 Controlled
Runoff = 12.90 cfs @ 3.15 hrs, Volume= 0.535 af, Depth= 2.13"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
1.860 98 Paved parking, HSG B
1.160 61 >75% Grass cover, Good, HSG B
3.020 84 Weighted Average
1.160 38.41% Pervious Area
1.860 61.59% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 11S: Post DA 4 Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=3.020 ac
Runoff Volume=0.535 af
Runoff Depth=2.13"
Tc=5.0 min
CN=84
12.90 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 46HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 13S: Post DA 4 Sheet Flow
Runoff = 1.78 cfs @ 3.65 hrs, Volume= 0.175 af, Depth= 0.67"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"
Area (ac) CN Description
* 3.110 61 >75% Grass cover, Good, HSG B
3.110 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
34.6 Direct Entry,
Subcatchment 13S: Post DA 4 Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
Charlotte 6-hr 10-yr
6hr - 10yr Rainfall=3.72"
Runoff Area=3.110 ac
Runoff Volume=0.175 af
Runoff Depth=0.67"
Tc=34.6 min
CN=61
1.78 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 47HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 1P: DS 24" Culvert
[57] Hint: Peaked at 626.69' (Flood elevation advised)
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 1.04" for 6hr - 10yr event
Inflow = 28.42 cfs @ 3.38 hrs, Volume= 2.139 af
Outflow = 28.42 cfs @ 3.38 hrs, Volume= 2.139 af, Atten= 0%, Lag= 0.0 min
Primary = 28.42 cfs @ 3.38 hrs, Volume= 2.139 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 626.69' @ 3.38 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=28.30 cfs @ 3.38 hrs HW=626.66' (Free Discharge)
1=Culvert (Barrel Controls 28.30 cfs @ 9.01 fps)
Pond 1P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=24.780 ac
Peak Elev=626.69'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
28.42 cfs
28.42 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 49HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 2P: Pond 1
Inflow Area = 11.320 ac, 65.19% Impervious, Inflow Depth = 2.21" for 6hr - 10yr event
Inflow = 50.08 cfs @ 3.15 hrs, Volume= 2.084 af
Outflow = 1.55 cfs @ 5.65 hrs, Volume= 2.060 af, Atten= 97%, Lag= 149.7 min
Primary = 1.55 cfs @ 5.65 hrs, Volume= 2.060 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 633.53' @ 5.65 hrs Surf.Area= 37,955 sf Storage= 78,172 cf
Plug-Flow detention time= 1,894.2 min calculated for 2.059 af (99% of inflow)
Center-of-Mass det. time= 1,894.1 min ( 2,105.0 - 210.9 )
Volume Invert Avail.Storage Storage Description
#1 631.50' 173,626 cf Main Pool Above Forebay Berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.50 32,265 0 0
636.00 44,902 173,626 173,626
Device Routing Invert Outlet Devices
#1 Primary 630.50'18.0" Round Culvert
L= 400.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 630.50' / 625.50' S= 0.0125 '/' Cc= 0.900
n= 0.013 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 631.50'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 633.00'12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 635.00'16.0' long Sharp-Crested Rectangular Weir 0 End Contraction(s)
#5 Secondary 635.50'20.0' 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=1.55 cfs @ 5.65 hrs HW=633.53' (Free Discharge)
1=Culvert (Passes 1.55 cfs of 12.41 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.34 cfs @ 6.85 fps)
3=Orifice/Grate (Orifice Controls 1.21 cfs @ 2.42 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.50' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 50HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 2P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=11.320 ac
Peak Elev=633.53'
Storage=78,172 cf
50.08 cfs
1.55 cfs
1.55 cfs
0.00 cfs
Pond 2P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302520151050Elevation (feet)636
635
634
633
632
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 52HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 3P: DS 24" Culvert
[57] Hint: Peaked at 625.93' (Flood elevation advised)
[79] Warning: Submerged Pond 2P Primary device # 1 OUTLET by 0.43'
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 1.58" for 6hr - 10yr event
Inflow = 23.67 cfs @ 3.36 hrs, Volume= 3.816 af
Outflow = 23.67 cfs @ 3.36 hrs, Volume= 3.816 af, Atten= 0%, Lag= 0.0 min
Primary = 23.67 cfs @ 3.36 hrs, Volume= 3.816 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 625.93' @ 3.36 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=23.67 cfs @ 3.36 hrs HW=625.93' (Free Discharge)
1=Culvert (Barrel Controls 23.67 cfs @ 7.53 fps)
Pond 3P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=29.030 ac
Peak Elev=625.93'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
23.67 cfs
23.67 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 54HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 4P: Pond 2
Inflow Area = 3.020 ac, 61.59% Impervious, Inflow Depth = 2.13" for 6hr - 10yr event
Inflow = 12.90 cfs @ 3.15 hrs, Volume= 0.535 af
Outflow = 0.30 cfs @ 6.03 hrs, Volume= 0.525 af, Atten= 98%, Lag= 172.6 min
Primary = 0.30 cfs @ 6.03 hrs, Volume= 0.525 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 623.81' @ 6.03 hrs Surf.Area= 11,021 sf Storage= 20,526 cf
Plug-Flow detention time= 1,533.5 min calculated for 0.525 af (98% of inflow)
Center-of-Mass det. time= 1,532.5 min ( 1,744.2 - 211.7 )
Volume Invert Avail.Storage Storage Description
#1 622.00' 45,378 cf Main pool above forebay berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
622.00 7,948 0 0
626.00 14,741 45,378 45,378
Device Routing Invert Outlet Devices
#1 Primary 615.15'15.0" Round Culvert
L= 310.0' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 615.15' / 611.44' S= 0.0120 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 622.00'1.7" Vert. Orifice/Grate C= 0.600
#3 Device 1 623.00'3.0" Vert. Orifice/Grate C= 0.600
#4 Device 1 624.75'16.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 625.50'20.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Primary OutFlow Max=0.30 cfs @ 6.03 hrs HW=623.81' (Free Discharge)
1=Culvert (Passes 0.30 cfs of 11.11 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.10 cfs @ 6.35 fps)
3=Orifice/Grate (Orifice Controls 0.20 cfs @ 3.98 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=622.00' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 55HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 4P: Pond 2
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=3.020 ac
Peak Elev=623.81'
Storage=20,526 cf
12.90 cfs
0.30 cfs
0.30 cfs
0.00 cfs
Pond 4P: Pond 2
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302826242220181614121086420Elevation (feet)626
625
624
623
622
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 57HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 1L: POI 1 COMBINED
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 1.04" for 6hr - 10yr event
Inflow = 28.42 cfs @ 3.38 hrs, Volume= 2.139 af
Primary = 28.42 cfs @ 3.38 hrs, Volume= 2.139 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 1L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=24.780 ac
28.42 cfs
28.42 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 58HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 2L: POI 1 COMBINED
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 1.58" for 6hr - 10yr event
Inflow = 23.67 cfs @ 3.36 hrs, Volume= 3.816 af
Primary = 23.67 cfs @ 3.36 hrs, Volume= 3.816 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 2L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=29.030 ac
23.67 cfs
23.67 cfs
Charlotte 6-hr 10-yr 6hr - 10yr Rainfall=3.72"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 59HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 3L: POI 4
Inflow Area = 6.130 ac, 30.34% Impervious, Inflow Depth > 1.37" for 6hr - 10yr event
Inflow = 2.01 cfs @ 3.66 hrs, Volume= 0.700 af
Primary = 2.01 cfs @ 3.66 hrs, Volume= 0.700 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 3L: POI 4
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)2
1
0
Inflow Area=6.130 ac
2.01 cfs
2.01 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 114HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=17.900 ac 2.79% Impervious Runoff Depth=1.43"Subcatchment 1S: Pre DA 1A
Flow Length=635' Tc=24.0 min CN=59 Runoff=28.27 cfs 2.136 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=3.68"Subcatchment 2S: Pre DA 1B
Tc=18.6 min CN=85 Runoff=33.62 cfs 2.112 af
Runoff Area=7.050 ac 9.65% Impervious Runoff Depth=2.13"Subcatchment 3S: Pre DA 2
Flow Length=1,795' Tc=15.5 min CN=68 Runoff=21.38 cfs 1.249 af
Runoff Area=0.860 ac 17.44% Impervious Runoff Depth=1.88"Subcatchment 4S: Pre DA 3
Flow Length=344' Tc=3.0 min CN=65 Runoff=3.37 cfs 0.135 af
Runoff Area=8.370 ac 2.99% Impervious Runoff Depth=1.43"Subcatchment 5S: Pre DA 4
Flow Length=2,170' Tc=34.6 min CN=59 Runoff=10.84 cfs 0.999 af
Runoff Area=11.320 ac 65.19% Impervious Runoff Depth=3.68"Subcatchment 6S: Post DA 1A Controlled
Tc=5.0 min CN=85 Runoff=80.22 cfs 3.475 af
Runoff Area=10.830 ac 0.00% Impervious Runoff Depth=1.36"Subcatchment 7S: Post DA 1A Sheet Flow
Flow Length=1,286' Tc=28.4 min CN=58 Runoff=14.72 cfs 1.228 af
Runoff Area=6.880 ac 0.00% Impervious Runoff Depth=3.68"Subcatchment 8S: Post DA 1B
Flow Length=340' Tc=18.6 min CN=85 Runoff=33.62 cfs 2.112 af
Runoff Area=3.840 ac 30.21% Impervious Runoff Depth=2.46"Subcatchment 9S: Post DA 2
Flow Length=100' Slope=0.0300 '/' Tc=13.0 min CN=72 Runoff=14.58 cfs 0.788 af
Runoff Area=0.550 ac 50.91% Impervious Runoff Depth=3.19"Subcatchment 10S: Post DA 3
Flow Length=35' Slope=0.0200 '/' Tc=9.0 min CN=80 Runoff=3.05 cfs 0.146 af
Runoff Area=3.020 ac 61.59% Impervious Runoff Depth=3.58"Subcatchment 11S: Post DA 4 Controlled
Tc=5.0 min CN=84 Runoff=20.92 cfs 0.902 af
Runoff Area=3.110 ac 0.00% Impervious Runoff Depth=1.58"Subcatchment 13S: Post DA 4 Sheet Flow
Tc=34.6 min CN=61 Runoff=4.51 cfs 0.409 af
Peak Elev=634.64' Inflow=58.35 cfs 4.247 afPond 1P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=58.35 cfs 4.247 af
Peak Elev=634.65' Storage=121,353 cf Inflow=80.22 cfs 3.475 afPond 2P: Pond 1
Primary=3.26 cfs 3.444 af Secondary=0.00 cfs 0.000 af Outflow=3.26 cfs 3.444 af
Peak Elev=630.74' Inflow=46.16 cfs 6.784 afPond 3P: DS 24" Culvert
24.0" Round Culvert n=0.013 L=60.0' S=0.0100 '/' Outflow=46.16 cfs 6.784 af
Peak Elev=624.81' Storage=31,869 cf Inflow=20.92 cfs 0.902 afPond 4P: Pond 2
Primary=1.21 cfs 0.890 af Secondary=0.00 cfs 0.000 af Outflow=1.21 cfs 0.890 af
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 115HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Inflow=58.35 cfs 4.247 afLink 1L: POI 1 COMBINED
Primary=58.35 cfs 4.247 af
Inflow=46.16 cfs 6.784 afLink 2L: POI 1 COMBINED
Primary=46.16 cfs 6.784 af
Inflow=4.91 cfs 1.299 afLink 3L: POI 4
Primary=4.91 cfs 1.299 af
Total Runoff Area = 80.610 ac Runoff Volume = 15.689 af Average Runoff Depth = 2.34"
84.79% Pervious = 68.350 ac 15.21% Impervious = 12.260 ac
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 116HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1A
Runoff = 28.27 cfs @ 3.45 hrs, Volume= 2.136 af, Depth= 1.43"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
17.400 58 Woods/grass comb., Good, HSG B
0.500 98 Paved parking, HSG B
17.900 59 Weighted Average
17.400 97.21% Pervious Area
0.500 2.79% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
9.8 535 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
24.0 635 Total
Subcatchment 1S: Pre DA 1A
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=17.900 ac
Runoff Volume=2.136 af
Runoff Depth=1.43"
Flow Length=635'
Tc=24.0 min
CN=59
28.27 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 117HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 1B
Runoff = 33.62 cfs @ 3.32 hrs, Volume= 2.112 af, Depth= 3.68"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
* 6.880 85 adj prop
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
18.6 Direct Entry,
Subcatchment 2S: Pre DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=6.880 ac
Runoff Volume=2.112 af
Runoff Depth=3.68"
Tc=18.6 min
CN=85
33.62 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 118HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA 2
Runoff = 21.38 cfs @ 3.31 hrs, Volume= 1.249 af, Depth= 2.13"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
* 0.680 98 Impervious
6.370 65 Woods/grass comb., Fair, HSG B
7.050 68 Weighted Average
6.370 90.35% Pervious Area
0.680 9.65% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
7.1 100 0.0400 0.23 Sheet Flow, Pre Sheet grass
Grass: Short n= 0.150 P2= 3.50"
0.3 35 0.0700 1.85 Shallow Concentrated Flow, Pre Shallow Wooded
Short Grass Pasture Kv= 7.0 fps
8.1 1,660 0.0300 3.40 17.02 Channel Flow, roadside ditch
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
15.5 1,795 Total
Subcatchment 3S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=7.050 ac
Runoff Volume=1.249 af
Runoff Depth=2.13"
Flow Length=1,795'
Tc=15.5 min
CN=68
21.38 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 119HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA 3
[49] Hint: Tc<2dt may require smaller dt
Runoff = 3.37 cfs @ 3.13 hrs, Volume= 0.135 af, Depth= 1.88"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
0.150 98 Paved parking, HSG B
0.710 58 Woods/grass comb., Good, HSG B
0.860 65 Weighted Average
0.710 82.56% Pervious Area
0.150 17.44% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
1.7 20 0.4000 0.19 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
1.3 324 0.7000 4.18 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
3.0 344 Total
Subcatchment 4S: Pre DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)3
2
1
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=0.860 ac
Runoff Volume=0.135 af
Runoff Depth=1.88"
Flow Length=344'
Tc=3.0 min
CN=65
3.37 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 120HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Pre DA 4
Runoff = 10.84 cfs @ 3.61 hrs, Volume= 0.999 af, Depth= 1.43"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
8.120 58 Woods/grass comb., Good, HSG B
8.370 59 Weighted Average
8.120 97.01% Pervious Area
0.250 2.99% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
10.0 670 0.0500 1.12 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
10.4 1,400 0.0130 2.24 11.21 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
34.6 2,170 Total
Subcatchment 5S: Pre DA 4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=8.370 ac
Runoff Volume=0.999 af
Runoff Depth=1.43"
Flow Length=2,170'
Tc=34.6 min
CN=59
10.84 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 121HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA 1A Controlled
Runoff = 80.22 cfs @ 3.15 hrs, Volume= 3.475 af, Depth= 3.68"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
7.380 98 Paved parking, HSG B
3.940 61 >75% Grass cover, Good, HSG B
11.320 85 Weighted Average
3.940 34.81% Pervious Area
7.380 65.19% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 6S: Post DA 1A Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=11.320 ac
Runoff Volume=3.475 af
Runoff Depth=3.68"
Tc=5.0 min
CN=85
80.22 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 122HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA 1A Sheet Flow
Runoff = 14.72 cfs @ 3.52 hrs, Volume= 1.228 af, Depth= 1.36"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
10.830 58 Woods/grass comb., Good, HSG B
10.830 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
17.5 100 0.0300 0.10 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 3.50"
6.8 500 0.0600 1.22 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
4.1 686 0.0200 2.78 13.90 Channel Flow,
Area= 5.0 sf Perim= 20.0' r= 0.25'
n= 0.030 Earth, grassed & winding
28.4 1,286 Total
Subcatchment 7S: Post DA 1A Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=10.830 ac
Runoff Volume=1.228 af
Runoff Depth=1.36"
Flow Length=1,286'
Tc=28.4 min
CN=58
14.72 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 123HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA 1B
Runoff = 33.62 cfs @ 3.32 hrs, Volume= 2.112 af, Depth= 3.68"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
* 6.880 85 Adjacent Developed Property
6.880 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
14.2 100 0.0500 0.12 Sheet Flow, Pre Dev Sheet
Woods: Light underbrush n= 0.400 P2= 3.50"
4.4 240 0.0330 0.91 Shallow Concentrated Flow, Pre Dev Shallow
Woodland Kv= 5.0 fps
18.6 340 Total
Subcatchment 8S: Post DA 1B
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=6.880 ac
Runoff Volume=2.112 af
Runoff Depth=3.68"
Flow Length=340'
Tc=18.6 min
CN=85
33.62 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 124HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 9S: Post DA 2
Runoff = 14.58 cfs @ 3.27 hrs, Volume= 0.788 af, Depth= 2.46"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
1.160 98 Paved parking, HSG B
2.680 61 >75% Grass cover, Good, HSG B
3.840 72 Weighted Average
2.680 69.79% Pervious Area
1.160 30.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
8.0 100 0.0300 0.21 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
13.0 100 Total
Subcatchment 9S: Post DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=3.840 ac
Runoff Volume=0.788 af
Runoff Depth=2.46"
Flow Length=100'
Slope=0.0300 '/'
Tc=13.0 min
CN=72
14.58 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 125HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 10S: Post DA 3
Runoff = 3.05 cfs @ 3.20 hrs, Volume= 0.146 af, Depth= 3.19"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
0.280 98 Paved parking, HSG B
0.270 61 >75% Grass cover, Good, HSG B
0.550 80 Weighted Average
0.270 49.09% Pervious Area
0.280 50.91% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
4.0 35 0.0200 0.14 Sheet Flow,
Grass: Short n= 0.150 P2= 3.50"
9.0 35 Total
Subcatchment 10S: Post DA 3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)3
2
1
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=0.550 ac
Runoff Volume=0.146 af
Runoff Depth=3.19"
Flow Length=35'
Slope=0.0200 '/'
Tc=9.0 min
CN=80
3.05 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 126HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 11S: Post DA 4 Controlled
Runoff = 20.92 cfs @ 3.15 hrs, Volume= 0.902 af, Depth= 3.58"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
1.860 98 Paved parking, HSG B
1.160 61 >75% Grass cover, Good, HSG B
3.020 84 Weighted Average
1.160 38.41% Pervious Area
1.860 61.59% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 11S: Post DA 4 Controlled
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=3.020 ac
Runoff Volume=0.902 af
Runoff Depth=3.58"
Tc=5.0 min
CN=84
20.92 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 127HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 13S: Post DA 4 Sheet Flow
Runoff = 4.51 cfs @ 3.60 hrs, Volume= 0.409 af, Depth= 1.58"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"
Area (ac) CN Description
* 3.110 61 >75% Grass cover, Good, HSG B
3.110 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
34.6 Direct Entry,
Subcatchment 13S: Post DA 4 Sheet Flow
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)5
4
3
2
1
0
Charlotte 6-hr100-yr
6hr-100yr Rainfall=5.34"
Runoff Area=3.110 ac
Runoff Volume=0.409 af
Runoff Depth=1.58"
Tc=34.6 min
CN=61
4.51 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 128HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 1P: DS 24" Culvert
[57] Hint: Peaked at 634.64' (Flood elevation advised)
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 2.06" for 6hr-100yr event
Inflow = 58.35 cfs @ 3.38 hrs, Volume= 4.247 af
Outflow = 58.35 cfs @ 3.38 hrs, Volume= 4.247 af, Atten= 0%, Lag= 0.0 min
Primary = 58.35 cfs @ 3.38 hrs, Volume= 4.247 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 634.64' @ 3.38 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=58.02 cfs @ 3.38 hrs HW=634.53' (Free Discharge)
1=Culvert (Barrel Controls 58.02 cfs @ 18.47 fps)
Pond 1P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)65
60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=24.780 ac
Peak Elev=634.64'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
58.35 cfs
58.35 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 130HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 2P: Pond 1
Inflow Area = 11.320 ac, 65.19% Impervious, Inflow Depth = 3.68" for 6hr-100yr event
Inflow = 80.22 cfs @ 3.15 hrs, Volume= 3.475 af
Outflow = 3.26 cfs @ 4.86 hrs, Volume= 3.444 af, Atten= 96%, Lag= 102.3 min
Primary = 3.26 cfs @ 4.86 hrs, Volume= 3.444 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 634.65' @ 4.86 hrs Surf.Area= 41,097 sf Storage= 121,353 cf
Plug-Flow detention time= 1,353.2 min calculated for 3.443 af (99% of inflow)
Center-of-Mass det. time= 1,353.7 min ( 1,561.6 - 207.9 )
Volume Invert Avail.Storage Storage Description
#1 631.50' 173,626 cf Main Pool Above Forebay Berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.50 32,265 0 0
636.00 44,902 173,626 173,626
Device Routing Invert Outlet Devices
#1 Primary 630.50'18.0" Round Culvert
L= 400.0' RCP, groove end w/headwall, Ke= 0.200
Inlet / Outlet Invert= 630.50' / 625.50' S= 0.0125 '/' Cc= 0.900
n= 0.013 Concrete pipe, straight & clean, Flow Area= 1.77 sf
#2 Device 1 631.50'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 633.00'12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 635.00'16.0' long Sharp-Crested Rectangular Weir 0 End Contraction(s)
#5 Secondary 635.50'20.0' 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=3.26 cfs @ 4.86 hrs HW=634.65' (Free Discharge)
1=Culvert (Passes 3.26 cfs of 13.44 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.42 cfs @ 8.54 fps)
3=Orifice/Grate (Orifice Controls 2.84 cfs @ 5.68 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.50' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 131HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 2P: Pond 1
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=11.320 ac
Peak Elev=634.65'
Storage=121,353 cf
80.22 cfs
3.26 cfs
3.26 cfs
0.00 cfs
Pond 2P: Pond 1
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302520151050Elevation (feet)636
635
634
633
632
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 133HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 3P: DS 24" Culvert
[57] Hint: Peaked at 630.74' (Flood elevation advised)
[79] Warning: Submerged Pond 2P Primary device # 1 INLET by 0.22'
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 2.80" for 6hr-100yr event
Inflow = 46.16 cfs @ 3.37 hrs, Volume= 6.784 af
Outflow = 46.16 cfs @ 3.37 hrs, Volume= 6.784 af, Atten= 0%, Lag= 0.0 min
Primary = 46.16 cfs @ 3.37 hrs, Volume= 6.784 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 630.74' @ 3.37 hrs
Device Routing Invert Outlet Devices
#1 Primary 622.81'24.0" Round Culvert
L= 60.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 622.81' / 622.21' S= 0.0100 '/' Cc= 0.900
n= 0.013 Concrete pipe, bends & connections, Flow Area= 3.14 sf
Primary OutFlow Max=45.97 cfs @ 3.37 hrs HW=630.69' (Free Discharge)
1=Culvert (Barrel Controls 45.97 cfs @ 14.63 fps)
Pond 3P: DS 24" Culvert
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)50
45
40
35
30
25
20
15
10
5
0
Inflow Area=29.030 ac
Peak Elev=630.74'
24.0"
Round Culvert
n=0.013
L=60.0'
S=0.0100 '/'
46.16 cfs
46.16 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 135HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 4P: Pond 2
Inflow Area = 3.020 ac, 61.59% Impervious, Inflow Depth = 3.58" for 6hr-100yr event
Inflow = 20.92 cfs @ 3.15 hrs, Volume= 0.902 af
Outflow = 1.21 cfs @ 4.40 hrs, Volume= 0.890 af, Atten= 94%, Lag= 75.2 min
Primary = 1.21 cfs @ 4.40 hrs, Volume= 0.890 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 624.81' @ 4.40 hrs Surf.Area= 12,719 sf Storage= 31,869 cf
Plug-Flow detention time= 1,269.7 min calculated for 0.889 af (99% of inflow)
Center-of-Mass det. time= 1,269.5 min ( 1,478.2 - 208.7 )
Volume Invert Avail.Storage Storage Description
#1 622.00' 45,378 cf Main pool above forebay berm (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
622.00 7,948 0 0
626.00 14,741 45,378 45,378
Device Routing Invert Outlet Devices
#1 Primary 615.15'15.0" Round Culvert
L= 310.0' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 615.15' / 611.44' S= 0.0120 '/' Cc= 0.900
n= 0.013, Flow Area= 1.23 sf
#2 Device 1 622.00'1.7" Vert. Orifice/Grate C= 0.600
#3 Device 1 623.00'3.0" Vert. Orifice/Grate C= 0.600
#4 Device 1 624.75'16.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Secondary 625.50'20.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Primary OutFlow Max=1.19 cfs @ 4.40 hrs HW=624.81' (Free Discharge)
1=Culvert (Passes 1.19 cfs of 11.60 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.13 cfs @ 7.97 fps)
3=Orifice/Grate (Orifice Controls 0.31 cfs @ 6.25 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 0.75 cfs @ 0.80 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=622.00' (Free Discharge)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 136HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Pond 4P: Pond 2
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (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
Inflow Area=3.020 ac
Peak Elev=624.81'
Storage=31,869 cf
20.92 cfs
1.21 cfs
1.21 cfs
0.00 cfs
Pond 4P: Pond 2
Total
Primary
Secondary
Stage-Discharge
Discharge (cfs)
302826242220181614121086420Elevation (feet)626
625
624
623
622
Orifice/Grate
Orifice/Grate
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 138HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 1L: POI 1 COMBINED
Inflow Area = 24.780 ac, 2.02% Impervious, Inflow Depth = 2.06" for 6hr-100yr event
Inflow = 58.35 cfs @ 3.38 hrs, Volume= 4.247 af
Primary = 58.35 cfs @ 3.38 hrs, Volume= 4.247 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 1L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)65
60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=24.780 ac
58.35 cfs
58.35 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 139HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 2L: POI 1 COMBINED
Inflow Area = 29.030 ac, 25.42% Impervious, Inflow Depth > 2.80" for 6hr-100yr event
Inflow = 46.16 cfs @ 3.37 hrs, Volume= 6.784 af
Primary = 46.16 cfs @ 3.37 hrs, Volume= 6.784 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 2L: POI 1 COMBINED
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)50
45
40
35
30
25
20
15
10
5
0
Inflow Area=29.030 ac
46.16 cfs
46.16 cfs
Charlotte 6-hr100-yr 6hr-100yr Rainfall=5.34"H&H Waxhaw - 180228
Printed 3/1/2018Prepared by Bohler Engineering
Page 140HydroCAD® 10.00-20 s/n 08583 © 2017 HydroCAD Software Solutions LLC
Summary for Link 3L: POI 4
Inflow Area = 6.130 ac, 30.34% Impervious, Inflow Depth > 2.54" for 6hr-100yr event
Inflow = 4.91 cfs @ 3.60 hrs, Volume= 1.299 af
Primary = 4.91 cfs @ 3.60 hrs, Volume= 1.299 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Link 3L: POI 4
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)5
4
3
2
1
0
Inflow Area=6.130 ac
4.91 cfs
4.91 cfs
Q = ciA
9.5 Disturbed Area (Acres) i 3.67
20.9 Peak Flow from 10-year Storm (cfs) C 0.6
17100 Required Volume ft3
6799 Required Surface Area ft2
58.3 Suggested Width ft
116.6 Suggested Length ft
190 Trial Top Width at Spillway Invert ft
236 Trial Top Length at Spillway Invert ft
3 Trial Side Slope Ratio Z:1
4 Trial Depth ft (2 to 13 feet above grade)
166 Bottom Width ft
212 Bottom Length ft
35192 Bottom Area ft2
173213 Actual Volume ft3 Okay
44902 Actual Surface Area ft2 Okay
20 Trial Weir Length ft
0.5 Trial Depth of Flow ft
21.2 Spillway Capacity cfs Okay
2 Skimmer Size (inches) Skimmer Size
0.167 Head on Skimmer (feet) (Inches)
3 Orifice Size (1/4 inch increments) 1.5
2.01 Dewatering Time (days) 2
Suggest about 3 days 2.5
3
4
5
6
8
SKIMMER BASIN #1(West)
Main Street Station
Q = ciA
4.78 Disturbed Area (Acres) i 3.67
10.5 Peak Flow from 10-year Storm (cfs) C 0.6
8604 Required Volume ft3
3421 Required Surface Area ft2
41.4 Suggested Width ft
82.7 Suggested Length ft
95 Trial Top Width at Spillway Invert ft
170 Trial Top Length at Spillway Invert ft
3 Trial Side Slope Ratio Z:1
3 Trial Depth ft (2 to 13 feet above grade)
77 Bottom Width ft
152 Bottom Length ft
11704 Bottom Area ft2
49069 Actual Volume ft3 Okay
11973 Actual Surface Area ft2 Okay
20 Trial Weir Length ft
0.5 Trial Depth of Flow ft
21.2 Spillway Capacity cfs Okay
2.5 Skimmer Size (inches) Skimmer Size
0.208 Head on Skimmer (feet) (Inches)
1.5 Orifice Size (1/4 inch increments) 1.5
3.63 Dewatering Time (days) 2
Suggest about 3 days 2.5
3
4
5
6
8
SKIMMER BASIN #2 (East)
Main Street Station
Project:
Location:
Project Number:
Date:
Designed:ATZ
Checked:MT
Outlet ID:
Pipe diameter=15 inches
Pipe slope=1 %
Roughness Coef.=0.013
Full Flow Capacity=7.12 cfs
Full flow velocity=5.81 ft/sec
Zone from graph above =1
Is grade of apron 10% or more:y Y/N
2 Length =7.5 ft.
Outlet pipe diameter=15 in.Width at Outlet =3.8 ft.
Outlet flowrate=7.1 cfs Width at end of Pad=12.4 ft.
Outlet velocity=5.81 ft/sec Stone diameter =8 in.
Material =Class B Thickness =12 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
Jan-18-2018
RRA
Inlcudes 1.1 Factor of Safety
Zone used =
NCC172039
Riprap Outlet Protection Design
Main Street Station
Waxhaw, NC
5.8 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=18 inches
Pipe slope=1 %
Roughness Coef.=0.013
Full Flow Capacity=11.59 cfs
Full flow velocity=6.56 ft/sec
Zone from graph above =1
Is grade of apron 10% or more:y Y/N
2 Length =9.0 ft.
Outlet pipe diameter=18 in.Width at Outlet =4.5 ft.
Outlet flowrate=11.6 cfs Width at end of Pad=14.9 ft.
Outlet velocity=6.56 ft/sec Stone diameter =8 in.
Material =Class B Thickness =12 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
NCC172039
Riprap Outlet Protection Design
Main Street Station
Waxhaw, NC
Special study required
Jan-18-2018
RRB
Inlcudes 1.1 Factor of Safety
Zone used =
6.6 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=1 %
Roughness Coef.=0.013
Full Flow Capacity=7.12 cfs
Full flow velocity=5.81 ft/sec
Zone from graph above =1
Is grade of apron 10% or more:y Y/N
2 Length =7.5 ft.
Outlet pipe diameter=15 in.Width at Outlet =3.8 ft.
Outlet flowrate=7.1 cfs Width at end of Pad=12.4 ft.
Outlet velocity=5.81 ft/sec Stone diameter =8 in.
Material =Class B Thickness =12 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
NCC172039
Riprap Outlet Protection Design
Main Street Station
Waxhaw, NC
Special study required
Jan-18-2018
RRC
Inlcudes 1.1 Factor of Safety
Zone used =
5.8 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=24 inches
Pipe slope=4 %
Roughness Coef.=0.013
Full Flow Capacity=49.90 cfs
Full flow velocity=15.88 ft/sec
Zone from graph above =3
Is grade of apron 10% or more:y Y/N
4 Length =16.0 ft.
Outlet pipe diameter=24 in.Width at Outlet =6.0 ft.
Outlet flowrate=49.9 cfs Width at end of Pad=24.5 ft.
Outlet velocity=15.88 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
Jan-18-2018
RRD
Inlcudes 1.1 Factor of Safety
Zone used =
NCC172039
Riprap Outlet Protection Design
Main Street Station
Waxhaw, NC
15.9 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