20081213 Ver 2_Stormwater Info_20090702

? ? ? Kimley-Horn
and Associates, Inc.
July 1, 2009
Mr. Joseph Gyamfi
NCDENR, Department of Water Quality
2321 Crabtree Blvd, Suite 250
Raleigh, NC 27604
Subject: South Tract City Boulevard Development
Charlotte, North Carolina
Our Ref: 018253029
DWQ Ref: 08-1213 V 2.
Dear Mr. Gyamfi:
JUL ?[R@[Emgo
9, 2009
WETLANDS AND SToRMVtsArrR BRANCH
On behalf of our client, Crescent Resources, LLC, we are writing in response to your
letter dated June 3, 2009. It is our understanding that DWQ has approved the
revised stormwater management plans with the condition that we provide a
description of the changes and supporting documentation. The revisions to the
previously approved set of plans include an increase in spillway width and revised
control structure elevations for the 10- and 25-year, 6-hour storm events.
Per your request, we hereby submit the following items:
• Two stormwater management calculation packages
We trust this meets your needs at this time, but please feel free to contact me at (704)
319-7699 with any questions or concerns.
Sincerely yours,
KIMLEY-HORN AND ASSOCIATES, INC.
Beverly Ro^?m, EI
:brr (KACHL LDEV\018253 Crescent\026 Belgate\Belgate Stormwater Management
Plan\Correspondence\L062609.D WQ.BRR_ST.doc)
NCDF?NR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Bevedy Eaves Perdue Coleen H. Sullins
Governor Director
June 3, 2009
Dee Freeman
Secretary
Mecklenburg County
DWQ EXP #t 08-1213v2
Mr. David Niekamp
Crescent Resources, LLC
400 S. Tryon Street, Suite 1300
Charlotte, NC 28285
Subject Property: South Tract City Blvd Development
APPROVAL OF REVISED STORMWATER MANAGEMENT PLAN (SMP)
Dear Mr. Niekamp,
la? R-9i E=5
l1
JUL 2 2009
DENR - WATER QUALITY
WETLANDS AND STORMVIAI A BRANCH
On June 2, 2009, the Division of Water Quality (DWQ) received one set of revised (updated) stormwater
management plans (SMP) for the subject project from Ms. Beverly Rosenbloom of Kimley-Horn and
Associates, Inc. The SMP, with last revision dated May 28, 2009, was. revised to satisfy the Phase 11
requirements of the City of Charlotte's Stormwater Ordinance.
The DWQ has reviewed the revised SMP and found no significant changes to the one previously
approved on December 3, 2008 except for a slight increase in drainage areas. The DWQ therefore
approves the newly revised plans to satisfy the stormwater condition required by the 401 Water Quality
Certification issued by the DWQ on August 25, 2008 for the subject project. You are however required
to meet the additional conditions 1 through 4 in the approval issued on December 3, 2008. In
addition, within 30 days of receipt of this letter, please send a detailed description of all changes, if
any, made to the previous SMP along with supporting documents including design calculations.
This letter completes the review of the Division of Water Quality under Section 401 of the Clean Water
Act. If you have any questions, please contact Joseph Gyamfi or Lia M. Gilleski at 919-733-1786.
Sincerely, /
Cynd€ Karoly, Supervisor
401 Oversight/Express Review Program
CBKJjg
cc: USACE Asheville Regulatory Field Office
DWQ Mooresville Regional Office
File Copy
Bev Rosenbloom, Kimley-Horn, 4651 Charlotte Park Dr., Suite 300, Charlotte, NC 28217
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carotin 27699-1650
Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604
Phone; 919-733-1786 t FAX: [phone]
Internet: http:llh2o.enr.state.nc.uslncwetlandsl
.One
Mma!!y
An Equal Opportunity 1 Affirmative Action Employer
0 Revised Stormwater Management Calculations:
South Tract
City Boulevard Development
Prepared for:
Crescent Resources, LLC
400 S. Tryon Street, Suite 1300
Charlotte, North Carolina 28202
Prepared by:
Kimley-Horn and Associates, Inc.
4651 Charlotte Park Drive, Suite 300
Charlotte, North Carolina 28217
Kimley-Horn
and Associates, Inc.
ag @IN O V/ [!D
J U L 2 2009
DENR - WATER QUALi fY
WETLANDS AND sTORWATaft
©Kimley-Horn and Associates, Inc. 2008
018253026
SOUTH TRACT CITY BOULEVARD DEVELOPMENT
CHARLOTTE, NORTH CAROLINA
REVISED STORMWATER MANAGEMENT CALCULATIONS
Prepared for:
Crescent Resources, LLC
400 S. Tryon Street, Suite 1300
Charlotte, North Carolina 28202
Prepared by:
Kimley-Horn and Associates, Inc.
4651 Charlotte Park Drive, Suite 300
Charlotte, North Carolina 28217
CARO?//i
Fs S/ -
A r.
• .F ¢
i??/y?'p' ?O ?\3 vq
March 2009
KHA Ref: 018253026
TABLE OF CONTENTS
OVERVIEW
SITE MAPS
SITE VICINITY MAP
SCS SOIL SURVEY
FEMA FIRM PANEL
WATERSHED MAPS
PRE-DEVELOPMENT WATERSHED MAP
POST-DEVELOPMENT WATERSHED MAP
WATER QUALITY
WET POND CALCULATIONS
ANTI-FLOTATION DEVICE CALCULATIONS
VOLUME AND SURFACE AREA TABLES
WET DETENTION BASIN SUPPLEMENT FORMS
WATER QUANTITY
CURVE NUMBER CALCULATIONS
TIME OF CONCENTRATION CALCULATIONS
HYDROCAD HYDROLOGY REPORT
¦
Jl vnmw,glCx MAlvACiCA&NT CALCULATIONS
South Tract city Boulevard Development, Charlotte, NC
i
Background
OVERVIEW
This report contains the approach and results of a stormwater analysis conducted for the South
Tract City Boulevard Development. The 41-acre project site is located in the south east quadrant
of the interchange of Interstate 85 and City Boulevard in the City of Charlotte (see vicinity map).
The site has been mass graded per City of Charlotte permit number GRS-2007223.
Existing Conditions
The existing on-site conditions (before mass grading) consisted of woods and meadow therefore
this ground cover was used in the analysis. The site topography varies from elevation 770 ft to
elevation 720 ft. Site runoff discharges into an existing stream in the middle portion of the site.
This stream drains to a culvert under City Blvd.
Floodplain/Floodway
The proposed site does not lie within a 100-year floodway boundary as determined by FIRM
Panel # 3717900070C.
Water Quality
Water quality treatment by means of permanent Best Management Practices (BMP's) will be
provided using two wet ponds as treatment. The ponds are designed to treat the first inch of
runoff per the Stormwater Model Ordinance for North Carolina and will draw down over a
period of two to five days. Wet Detention Basin 1 and Wet Detention Basin 2 have been
designed to provide a minimum 90% average annual removal of Total Suspended Solids (TSS).
Water Quantity
The proposed wet detention ponds have been designed to address the water quantity
requirements to match pre- and post-development peak runoff rates for the 1-year, 24-hour storm
events. (These ponds will also control the peak runoff rates for the 10- and 25-year, 6-hour storm
events per the City of Charlotte rezoning notes on Petition 2006-155. However, these water
quantity requirements will be reviewed by the City of Charlotte when the site develops.) The
100-year, 24-hour storm event was checked for 6" of freeboard at the top of bank.
Results
Pre-development
1-yr, 24-hr storm Post-development
1-yr, 24-hr storm
DA-1 4.17 cfs 1.30 cfs
DA-2 1.46 cfs 1.37 cfs
STORMWATER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, NC
Conclusion
The proposed wet detention basins were designed using methods prescribed by the
aforementioned resources. HydroCAD software was utilized to evaluate the pre-development
and post-development flow rates. HydroCAD utilizes TR-55 methods of calculating times of
concentration (based on sheet, shallow concentrated, and channelized flows) and SCS curve
number method of generating hydrographs (results are provided in Appendix C). Based on the
analyses provided herein, the proposed system will be adequate to address the stormwater
requirements of the North Carolina Department of Environment and Natural Resources, Division
of Water Quality.
61 uRMWAIER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, NC
SITE MAPS
STORMWA TER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
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Kimley-Horn and Associates, Inc. NTS '
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PRE-DEVELOPMENT
WATERSHED MAP
STORM WATER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
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POST-DEVELOPMENT
WATERSHED MAP
STORMWATER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
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WET POND CALCULATIONS
STORM6VATER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
I
C KmleyHom
and Associates, Inc.
WET DETENTION BASIN
Project Information
Project Name: Belgate - Southern Tract
KHA Project #: 018253026
Designed by: BRR Date: 10/8/2008
Revised by: BRR Date: 10/27/2008
Revised by: BRR Date: 11/14/2008
Site Information
Sub Area Location: Drainage Area 1
Drainage Area (DA) = 7.44 Acres
Impervious Area (IA) = 6.43 Acres
Percent Impervious (1) = 86.4 %
Required Surface Area
Permanent Pool Depth: 4 ft
SA/DA = 4 (90% TSS Removal via Pond)
Min Req'd Surface Area = 12963 sf (at Permanent Pool)
Required Storage Volume:
Design Storm = 1 inch (Project Does Not Drain to SA waters)
Determine Rv Value = 0.05 +.009 (I) = 0.83 in/in
Storage Volume Required = 22357 cf (above Permanent Pool)
Elevations Area (s.f.)
Bank Elevation = 732.00 ft
Top of Pond Elevation = 732.00 ft
Temporary Pool Elevation = 727.70 ft 19,373
Permanent Pool Elevation = 726.00 ft 14,257
Shelf Beginning Elevation = 726.50 ft
Forebay Weir = 728.00 ft
Shelf Ending Elevation = 725.50 ft
Sediment Cleanout Elevation = 718.00 ft
Bottom Elevation = 717.00 ft
Wet Basin Areas/Volumes (Elevation = 727.70)
Area @ Top of Temporary Pool = 19373 sf (Elevation = 726.00)
' Area @ Top of Permanent Pool = 14257 sf
Volume of Temporary Storage = 28586 cf
Side Slopes of Pond = 3 :1
Side Slopes of Shelf = 1 0 :1
Side Slopes of Pond (below shelf) = 3 :1
Yes ( 14257 > 12963) sf
Is Permanent Pool Surface Area Sufficient (yes/no)?
Volume of Storage Provided 28586 cf
Total Volume Sufficient (yes/no)? Yes
Orifice Size = 2.30 inches

WET DETENTION BASIN
Project Information
Project Name: Belgate - Southern Tract
KHA Project #: 018253026
Designed by: BRR Date:
Revised by: Date:
Revised by: BRR Date:
Site Information
4/1/2008
11/1412008
Sub Area Location: Drainage Area 1
Drainage Area (DA) = 7.44 Acres
Impervious Area (IA) = 6.48 Acres
Percent Impervious (1) = 87.1 % (Drainage Area)
Orifice Sizing
Q2 Days = 0.1654 cfs
Q5 Days = 0.0662 CfS
Orifice Size = 2.30 in
Q orifice = 0.102 cfs
Drawdown Time = 3.3 days
(Flowrate required for a 2 day drawdown)
(Flowrate required for a 5 day drawdown)
(Diameter)
less than 5 days (yes/no) ? yes
greater than 2 days (yes/no) ? yes
Orifice Equation: Q=CAgd(2gh) Q2 < Q < Q5
c=0.6
A9= Area of Pipe = n/4D2
g = gravity = 32.2 ft/s2
h = orifice head = 1/3 (TPE-PPE-1/2D)
TPE = Temporary Pool Elevation
PPE = Permanent Pool Elevation
D = Diameter
C Kirnley-Horn
and Associates, Inc.
WET DETENTION BASIN
Project Information
Project Name:
KHA Project #:
Designed by:
Revised by:
Revised by:
Belgate - Southern Tract
018253026
BRR Date: 10/8/2008
BRR Date: 10/19/2008
BRR Date: 11/1412008
Site Information
Sub Area Location: Drainage Area 2
Drainage Area (DA) = 25.11 Acres
Impervious Area (IA) = 18.53 Acres
Percent Impervious (1) = 73.8 %
Required Surface Area
Permanent Pool Depth: 4.35 ft
SA/DA = 3.375 (90% TSS Removal via Pond)
Min Req'd Surface Area = 36915 sf (at Permanent Pool)
Required Storage Volume:
Design Storm = 1 inch (Project Does Not Drain to SA waters)
Determine Rv Value = 0.05 +.009 (1) = 0.71 in/in
Storage Volume Required = 65095 cf (above Permanent Pool)
Elevations Area (s.f.)
Bank Elevation = 725.00 ft
Top of Pond Elevation = 725.00 ft
Temporary Pool Elevation = 720.60 ft 46,100
Permanent Pool Elevation = 719.00 ft 38,235
Shelf Beginning Elevation = 719.50 ft
Forebay Weir = 722.00 ft
Shelf Ending Elevation = 718.50 ft
Sediment Cleanout Elevation = 712.00 ft
Bottom Elevation = 711.00 ft
Wet Basin Areas/Volumes
Area @ Top of Temporary Pool = 46100 sf (Elevation = 720.60)
' Area @ Top of Permanent Pool = 38235 sf (Elevation = 719.00)
Volume of Temporary Storage = 67468 cf
Side Slopes of Pond = 3 : 1
Side Slopes of Shelf = 1 0 : 1
Side Slopes of Pond (below shelf) = 3 : 1
i Is Permanent Pool Surface Area Sufficient (yes/no)? Yes ( 38235 > 36915) sf
Volume of Storage Provided 67468 cf
Total Volume Sufficient (yes/no)? Yes
Orifice Size = 2.90 inches
WET DETENTION BASIN
Project Information
Project Name: Belgate - Southern Tract
KHA Project #: 018253026
Designed by: BRR Date:
Revised by: BRR Date:
Revised by: BRR Date:
Site Information
Sub Area Location: Drainage Area 2
Drainage Area (DA) = 24.40 Acres
Impervious Area (IA) = 18.30 Acres
Percent Impervious (1) = 75.0 % (Drainage Area)
Orifice Sizing
Q2 Days = 0.3904 cfs (Flowrate required for a 2 day drawdown)
Qs Days = 0.1562 cfs (Flowrate required for a 5 day drawdown)
Orifice Size = 2.90 in (Diameter)
Q orifice = 0.155 cfs
Drawdown Time = 5.0 days
less than 5 days (yes/no) ? yes
greater than 2 days (yes/no) ? yes
Orifice Equation: Q=cA9d(2gh) Q2 < Q < Q5
c = 0.6
Ay= Area of Pipe = Ti/4D 2
g = gravity = 32.2 ft/S2
h = orifice head = 1/3 (TPE-PPE-1/2D)
TPE = Temporary Pool Elevation
PPE = Permanent Pool Elevation
D = Diameter
10/19/2008
11/3/2008
11/14/2008
Wmley-Han
CC" and Associates, Inc.
Pre vs. Post Runoff Analysis
Composite Curve Number (CN)
Project Information
Project Name: Belgate - South Tract
KHA Project #: 018253029
Designed by: BRR Date: 10/6/2008
Revised by: BRR Date: 11/14/2008
Revised by: Date:

Drainage Area
Name
Drainage
Location
Cover/Soil
Name (Type)

Cover Description`
Hydrologic Soil
Group

Curve # (CN)"

Area (ac)
Product of
CN x area Composite
Curve Number
(CN)
PRE-DEVELOPMENT

DA-1
OUTFALL 1 Mecklenburg,
Enon, Wilkes Woods
Good Condition
C 70 5.04 353
70
Meadow
Good Condition
B 71 5.04 358
71
10.08 711 70.5

DA-2
OUTFALL 1 Mecklenburg,
Enon, Wilkes Woods
Good Condition
C 70 2.95 207
70
Mecklenburg,
Enon, Wilkes Meadow
Good Condition
C 71 2.95 209
71

Cecil
Meadow
Good Condition i I

B 58 10.69 620

58

Cecil Woods
Good Condition
B 55 10.69 588
55
27.28 1624 59.5
Total Pre-development Area = 37.36
POST DEVELOPMENT
DA-1 POND 1 Impervious 98 6.43 631 98
Mecklenburg,
Enon, Wilkes Open Space - Good Condition
(from City Blvd) C 73 0.29 21
73
Mecklenburg,
Enon, Wilkes
Open Space - Good Condition C 74 0.71 53
74
7.44 704.63 94.72
Mecklenburg,
UND DA-1 OUTFALL 1 Enon, Wilkes i
Open Space - Good Condition C 74 0.90 67
74
0.90 66.60 1 74.00

DA-2
POND 2
Impervious i
98 15.40 1509
98
Mecklenburg,
Enon, Wilkes
Open Space - Good Condition
C 74 0.83 61
74
Cecil Open Space - Good Condition B 61 4.11 251 61
!
Roadway - Impervious I j
98 3.13 307
98
Mecklenburg,
Enon, Wilkes
Roadway - Open Space (
C 74 1.54 114
74
Cecil Roadway - Open Space B 61 1 0.10
I 6
61
25.11 2248.13 89.53 -

UND DA-2
OUTFALL 2 Mecklenburg,
Enon, Wilkes Open Space - Good Condition
C 74 2.96 219
74
Cecil Open Space - Good Condition B 61 2.97 181 61
5.93 400.21 67.49
Total Post-development Area = 39.38
Cover Descriptions per TR-55 Manual
" From TR-55 Manual, Table 2-2 a & c
I
I K:\CHL_LDEV\018253 Crescent\026 Belgate\Belgate Stormwater Management Plan\Calculations\South Tract\Stormwater Calculations_2008-10-06.xls 1 of 1
ANTI-FLOTATION DEVICE CALCULATIONS
STORMWATER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
run 121d% =11 Im
NCDENR ANTIFLOATATION DEVICE DESIGN CALCULATIONS
(per NCDENR Manual)
Project Information
Project Name: Belgate - Southern Tract
KHA Project #: 018253026
Designed by: BRR Date: 11/3/2008
Revised by: Date:
Revised by: Date:
Revised by: Date:
Pond 1
Drainage Area Information:
Drainage Area (ac) = 7.15
Flow (Q.) (cts) = 12.8
Storage Dimensions:
Basin Side Slopes L : 1 ) = 3.0
Storage Depth "R" (ft) = 9.0
Top of Basin Elevation
Temporary Pool Elevation
Permanent Pool Elevation
Bottom of Basin Elevation
(3:1 max side slopes)
Elev (ft) Area SF Cumulative Volume (CF)
732.00 27.972
730.00 23.807 124,239
727.70 16.459 77,934
726.00 11.541 54.134
723.00 7.735 25,220
720.00 3,846 7.848
717.00 1,386 0
Control Structure Length (in) = 48
Control Structure Width (in) = 36
Riser Area (so = 12.00 (Check dser geometry vs. area equation)
Volume of Water Displaced (co = 108.0
Weight of Water Displaced (lb) = 6,739
Min. Required Weight of Anchor Block (lb) = 7,413 (1.1 factor of safety)
Anchor Size:
Width (If) = 4.4
Length (If) = 5.0
Height (If) = 4.00
Weight of Anchor (lb) = 7,709 O.K. > Minimum Required Weight
Sizing of Emergency Spillway:
0, (cts) = 12.8
C6,._r (cts) = 12.8 (Riser ignored)
Water Depth Over Spillway (ft) = 0.5
Spillway Length (ft) = 15.0 (10 ft minimum spillway length, Cw=2.7)
Spillway Crest Elevation (ft) = 730.5 (1 ft min. above sediment storage depth)
Freeboard (ft) = 1.04 (1 ft minimum)
Page 1 of 1
Cc" ,k..
NCDENR ANTIFLOATATION DEVICE DESIGN CALCULATIONS
(per NCDENR Manual)
Project Information
Project Name: Belgate - Southern Tract
KHA Project #: 018253026
Designed by: BRR Date: 11/32008
Revised by: Date:
Revised by: Date:
Revised by: Date:
Pond 2
Drainage Area Information:
Drainage Area (ac) = 23.90
Flow (05D) ids) = 16.7
Storage Dimensions:
Basin Side Slopes LX: 11 = 3.0 (3:1 max side slopes)
Storage Depth "R" (ft) = 7.0
Top of Basin Elevation
Temporary Pool Elevation
Permanent Pool Elevation
Bottom of Basin Elevation
Elev ft Area SF Cumulative Volume (CF)
725.00 60.143
723.00 53.616 332 340
720.70 39.312 225,473
719.00 31.750 165,071
716.00 22.055 84.363
714.00 17,794 44.514
711.00 11.882 0

Sizing of Antiflotation Block:
Control Structure Length (in) = 48
Control Structure Width (in) = 36
Riser Area (so = 12.00 (Check riser geometry vs. area equation)
Volume of Water Displaced (d) = 96.0
Weight of Water Displaced (Ib) = 5,990
Min. Required Weight of Anchor Block (lb) = 6,589 (1.1 factor of safety)
Anchor Size:
Width (If) = 4.1
Length (If) = 4.8
Height (If) = 4.00
Weight of Anchor (lb) = 6,896 O.K. - Minimum Required Weight
Sizing of Emergency Spillway:
0. (ds) = 16.7
O,gµ,Y (ds) = 16.7 (Riser ignored)
Water Depth Over Spillway (ft) = 0.5
Spillway Length (ft) = 40.0 (10 ft minimum spillway length, Cyr-2.7)
Spillway Crest Elevation (ft) = 7237 (1 ft min. above sediment storage depth)
Freeboard (ft) = 1.01 (1 ft minimum)
Page 1 of 1
VOLUME AND SURFACE AREA TABLES
STORMWA TER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
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WET DETENTION BASIN
SUPPLEMENT FORMS
STORADVA TER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
Permit No
A=*A
i NCDENR
(to be provided by DWQ)
O?O? W A TE9OG
O T
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
1. PROJECT INFORMATION
Project name Belgate Southern Tract
Contact person Beverly Rosenbloom, El
Phone number 704-319-7699
Date 3/31/2009
Drainage area number 1
!!. DESIGN INFORMATION
Site Characteristics
Drainage area 324,086.40 ft2
Impervious area 280,090.80 ft
% impervious 86.42 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 22,357.00 ft3
Volume provided 28,586.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth in
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth 2.58 in
Rational C, pre-development 0.28 (unitless)
Rational C, post-development 0.88 (unitless)
Rainfall intensity: 1-yr, 24-hr storm 0.12 in/hr
Pre-development 1-yr, 24-hr peak flow 2.63 ft3/sec
Post-development 1-yr, 24-hr peak flow 9.25 ft3/sec
Pre/Post 1-yr, 24-hr peak flow control 6.62 ft3/sec
Basin Elevations
Basin bottom elevation 717.00 ft
Sediment cleanout elevation 718.00 ft
Bottom of shelf elevation 725.50 ft
Permanent pool elevation 726.00 ft
SHWT elevation 712.00 ft
Top of shelf elevation 726.50 ft
Temporary pool elevation 727.70 ft
1 Form SW401-Wet Detention Basin-Rev.4 Parts I.8 II. Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
IL DESIGN INFORMATION
Volume and Surface Area Calculations
SA/DA ratio 4.00 (unitless)
Surface area at the bottom of shelf 11,462.00 e
Volume at the bottom of shelf 52,187.00 ft3
Permanent pool, surface area required 12,458.00 ft
Permanent pool, surface area provided 14,257.00 ftz OK
Permanent pool volume 58,619.00 ft3
Average depth for SA/DA tables 4.11 ft OK
Surface area at the top of shelf 17,373.00 ftz
Volume at the top of shelf 66,405.00 ft3
Forebay volume 10,977.00 ft3
Forebay % of permanent pool volume 18.73 % OK
Temporary pool, surface area provided 19,373.00 ft2
Drawdown Calculations
Treatment volume drawdown time 3.30 days OK
Treatment volume discharge rate 0.10 ff3/s
Pre-development 1-yr, 24-hr discharge 2.63 ft3/s OK
Post-development 1-yr, 24-hr discharge 1.76 ft3/s OK
Additional Information
Diameter of orifice 2.3 in
Design TSS removal 90 %
Basin side slopes 3.00 :1 OK
Vegetated shelf slope 10.00 :1 OK
Vegetated shelf width 10.00 It OK
Length of flowpath to width ratio 4.40 :1 OK
Length to width ratio 3.30 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 2.25 It OK
Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal
Recorded drainage easement provided? Y (Y or N) OK
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies 24-HR EMERGENCY PUMP

I Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
Permit N
(to be provided by DWQ)
Ill. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
IMF C-3 1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
- Off-site drainage (if applicable),
' - Delineated drainage basins (include Rational C coefficient per basin),
- Basin dimensions,
- Pretreatment system,
' - High flow bypass system,
Maintenance access,
- Proposed drainage easement and public right of way (ROVE,
' - Overflow device, and
- Boundaries of drainage easement.
K C4 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
' - Outlet structure with trash rack or similar,
- Maintenance access,
- Permanent pool dimensions,
' - Forebay and main pond with hardened emergency spillway,
- Basin cross-section,
- Vegetation specification for planting shelf, and
- Filter strip.
'
13XK _C-7_ 3. Section view of the dry detention basin (1" = 20' or larger) showing:
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
' - Inlet and outlet structures.
_C-3 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
_C-4 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
'
g?c Attached 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
' _Calc book- 7. The supporting calculations.
-Attached- 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
-Attached- 9. A copy of the deed restrictions (if required).
-Attached- 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1
Permit No.
(to be provided by DWQ)
AT"tA
WDENR
1
1
1
1
1
1
1
1
1
1
1
1
1
O?o? W ATF9OG
o
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Belgate Southern Tract
Contact person Beverly Rosenbloom, El
Phone number 704-319-7699
Date 3131/2009
Drainage area number 2
II. DESIGN' INFORMATION
Site Characteristics
Drainage area 1,093,791.60 ft2
Impervious area 807,166.80 ft2
% impervious 73.80 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 65,095.00 ft3
Volume provided 67,468.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth in
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required fts
Volume provided ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth 2.58 in
Rational C, pre-development 0.28 (unitless)
Rational C, post-development 0.79 (unitless)
Rainfall intensity: )-yr, 24-hr storm 0.12 in/hr
Pre-development 1-yr, 24-hr peak flow 1.57 ft3/sec
Post-development 1-yr, 24-hr peak flow 24.36 ft3/SeC
Pre/Post 1-yr, 24-hr peak flow control 22.79 ft3/sec
Basin Elevations
Basin bottom elevation 711.00 ft
Sediment cleanout elevation 712.00 ft
Bottom of shelf elevation 718.50 ft
Permanent pool elevation 719.00 ft
SHWT elevation 708.00 ft
Top of shelf elevation 719.50 ft
Temporary pool elevation 720.60 ft
Form SW401-Wet Detention Basin-Rev.4
Parts I. & II. Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
!L DESIGN INFORMATION
Volume and Surface Area Calculations
SAIDA ratio 3.38 (unitless)
Surface area at the bottom of shelf 33,899.00 ft2
Volume at the bottom of shelf 163,941.00 ft3
Permanent pool, surface area required 35,872.00 ftz
Permanent pool, surface area provided 38,235.00 ft2 OK
Permanent pool volume 181,976.00 ft3
Average depth for SAIDA tables 4.76 ft OK
Surface area at the top of shelf 42,920.00 ft2
Volume at the top of shelf 202,265.00 ft3
Forebay volume 33,586.00 ft3
Forebay % of permanent pool volume 18.46 % OK
Temporary pool, surface area provided 46,100.00 ft2
Drawdown Calculations
Treatment volume drawdown time 5.00 days OK
Treatment volume discharge rate 0.16 ft3/s
Pre-development 1-yr, 24-hr discharge 1.57 ft3/s OK
Post-development 1-yr, 24-hr discharge 1.51 ft3/s OK
Additional Information
Diameter of orifice 2.9 in
Design TSS removal 90 %
Basin side slopes 3.00 :1 OK
Vegetated shelf slope 10.00 :1 OK
Vegetated shelf width 10.00 ft OK
Length of flowpath to width ratio 4.10 :1 OK
Length to width ratio 3.20 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 2.65 ft OK
Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal
Recorded drainage easement provided? Y (Y or N) OK
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies 24-HR EMERGENCY PUMP
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
' Permit No.
(to be provided by DWQ)
111. REQUIRED ITEMS CHECKLIST
' Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
_C-3_ 1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
' - Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
- Basin dimensions,
- Pretreatment system,
- High flow bypass system,
- Maintenance access,
- Proposed drainage easement and public right of way (ROW),
- Overflow device, and
- Boundaries of drainage easement.
_C4 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
Outlet structure with trash rack or similar,
- Maintenance access,
- Permanent pool dimensions,
- Forebay and main pond with hardened emergency spillway,
- Basin cross-section,
- Vegetation specification for planting shelf, and
- Filter strip.
K? _C-7_ 3. Section view of the dry detention basin (1" = 20' or larger) showing:
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
- Inlet and outlet structures.
_C-3 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
' on the plans prior to use as a wet detention basin.
_ _C-4 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
A'tV" t 1_ to verify volume provided.
1 r s°t"" 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
_Calc book- 7. The supporting calculations.
441? -Attached- 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
-Attached- 9. A copy of the deed restrictions (if required).
-Attached- 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
1 Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1
CURVE NUMBER CALCULATIONS

STORMWA TER MANAGEMENT CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
I \ Khnley-Hom
I , I , and Associates, Inc.
Pre vs. Post Runoff Analysis
Composite Curve Number (CN)
Project Information
Project Name: Belgate - South Tract
KHA Project #: 018253029
Designed by: BRR
Revised by: BRR
Revised by:
Date: 10/6/2008
Date: 11/14/2008
Date:

Drainage Area
Name
Drainage
Location
Cover/Soil
Name (Type)

Cover Description`
Hydrologic Soil
Group

Curve # (CN)"

Area (ac)
Product of
CN x area Composite
Curve Number
(CN)
PRE-DEVELOPMENT

DA-1
OUTFALL 1 Mecklenburg,
Enon, Wilkes Woods
Good Condition
C 70 5.04 353
70
Meadow
Good Condition
B 71 5.04 358
71
i 10.08 1 711 70.5 ,

DA-2
OUTFALL 1 Mecklenburg,
Enon, Wilkes Woods
Good Condition
C 70 2.95 207
70
Mecklenburg,
Enon, Wilkes Meadow
Good Condition
C 71 2.95 209
71

Cecil Meadow
Good Condition
B 58 10.69 620
58

Cecil Woods
Good Condition
B 55 10.69 588
55
27.28 1624 59.5
Total Pre-development Area = 37.36
POST DEVELOPMENT
DA-1 POND 1 Impervious 98 6.43 631 98
Mecklenburg,
Enon, Wilkes Open Space - Good Condition
(from City Blvd) j
C 73 0.29 21
73
Mecklenburg,
Enon, Wilkes
Open Space - Good Condition
C 74 0.71 53
74
7.44 704.63 1 94.72

UND DA-1 Mecklenburg,
OUTFALL 1 Enon, Wilkes Open Space - Good Condition C 74 0.90 67
74
0.90 ! 66.60 74.00
DA-2 POND 2 Impervious
!
98 15.40 1509
98
Mecklenburg,
Enon, Wilkes
Open Space - Good Condition I i
C 74 0.83 61
74
Cecil Open Space - Good Condition B 61 4.11 251 61
Roadway - Impervious 98 3.13 307 96
Mecklenburg,
En n. Wilkes
Roadway - Open Space
C 74 1.54 114
74
Cecil Roadway - Open Space B 61 0.10 6 61
25.11 1 2248.13 89.53

UND DA-2
OUTFALL 2 Mecklenburg,
Enon, Wilkes
Open Space - Good Condition
C 74 2.96 219
74

Cecil
Open
Space -Good Condition i

g 61 2.97 j 181

61
5.93 400.21 1 67.49
Total Post-development Area = 39.38
' Cover Descriptions per TR-55 Manual
From TR-55 Manual, Table 2-2 a & c
K:\CHL_LDEV\018253 Crescent\026 Belgate\Belgate Stormwater Management Plan\Calculations\South Tract\Stormwater Calculations_2008-1 0-06.xls 1 of 1

TIME OF CONCENTRATION
CALCULATIONS
LAU61UIV CUNIROL CALCULATIONS
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HYDROCAD HYDROLOGY REPORT
WET DETENTION POND I
' EROSION CONTROL CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
1S
Pre-dev DA-1
2S 45
Post-de DA-1 Post-dev ND DA-1
3P' 8P
South Tract Wet Pond 1 Outfall 1
Subca Each on Link.
Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paoe 2
Summary for Subcatchment 1S: Pre-dev DA-1
Runoff = 4.17 cfs @ 12.23 hrs, Volume= 0.442 af, Depth> 0.53"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
10.080 71
10.080 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
25.2 Direct Entry, From spreadsheet
Subcatchment 1S: Pre-dev DA-1
Hydrograph
Runoff
w
v
3
0
U-
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Time (hours)
Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 2S: Post-dev DA-1
' Runoff = 25.35 cfs @ 11.95 hrs, Volume= 1.264 af, Depth> 2.04"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
7.440 95
7.440 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, From spreadsheet
Subcatchment 2S: Post-dev DA-1
Hydrograph
Runoff
3
0
LL
U i L 3 a o e i s 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Time (hours)
Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=258"
Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009
HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 4S: Post-dev UND DA-1
Runoff = 1.01 cfs @ 11.97 hrs, Volume= 0.049 af, Depth> 0.65"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
0.900 74
0.900 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
w
0
LL
Subcatchment 4S: Post-dev UND DA-1
Hydrograph
1 cfs
1.0 ..:....
....... --- ---- --- -- ...- - --------------
CharJotte' 24-hr
1-yr 1 yr - 24 hr
Rainfall=2.68"
:Runoff Area=0.900 ac
btu off'VolU e=:0.049 of
Runoff `D6Pth>0.05,
tc=5. min
GN=74
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Time (hours)
® Runoff
Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfal1=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5
Summary for Pond 3P: South Tract Wet Pond 1
Inflow Area = 7.440 ac, 0.00% Impervious, Inflow Depth > 2.04" for 1 yr - 24 hr event
Inflow = 25.35 cfs @ 11.95 hrs, Volume= 1.264 of
Outflow = 1.23 cfs @ 12.97 hrs, Volume= 0.555 af, Atten= 95%, Lag= 61.2 min
Primary = 1.23 cfs @ 12.97 hrs, Volume= 0.555 of
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Peak Elev= 728.00' @ 12.97 hrs Surf.Area= 19,939 sf Storage= 35,291 cf
Plug-Flow detention time= 301.2 min calculated for 0.555 of (44% of inflow)
Center-of-Mass det. time= 181.3 min ( 964.5 - 783.2 )
Volume Invert Avail.Storage Storage Description
#1 726.00' 130,637 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
726.00 14,257 0 0
727.00 18,100 16,179 16,179
728.00 19,930 19,015 35,194
729.00 21,832 20,881 56,075
730.00 23,807 22,820 78,894
731.00 25,853 24,830 103,724
732.00 27,972 26,913 130,637
Device Routing Invert Outlet Devices
#1 Primary 726.00' 24.0" x 51.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 725.00' S=0.0196/' Cc= 0.900 n=0.013
#2 Device 1 726.00' 2.3" Vert. Orifice/Grate C= 0.600
#3 Device 1 727.75' 2.50' W x 1.00'H Vert. Orifice/Grate C=0.600
#4 Secondary 730.50' 15.0' long x 13.5' breadth Emergency Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.62 2.66 2.70 2.66 2.65 2.66 2.65 2.63
#5 Device 1 729.50' 14.0' long x 0.5' breadth Grate on Overflow Structure
Head (feet) 0.20 0.40 0.60 0.80 1.00
Coef. (English) 2.80 2.92 3.08 3.30 3.32
Primary OutFlow Max=1.22 cfs @ 12.97 hrs HW=728.00' (Free Discharge)
t1=Culvert (Passes 1.22 cfs of 15.16 cfs potential flow)
U-==Grate Orifice/Grate (Orifice Controls 0.19 cfs @ 6.65 fps)
Orifice/Grate (Orifice Controls 1.03 cfs @ 1.62 fps)
on Overflow Structure ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=726.00' (Free Discharge)
L4=Emergency Spillway (Controls 0.00 cfs)
Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009
HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 6
Pond 3P: South Tract Wet Pond 1
Hydrograph
d
u
® Inflow '
r-M Outflow
Primary
12 Secondary
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 ZO 21 ZZ Zs Z4
Time (hours)
Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 7
Stage-Discharge for Pond 3P: South Tract Wet Pond 1
Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs)
726.00 0.00 0.00 0.00
726.10 0.02 0.02 0.00
726.20 0.04 0.04 0.00
726.30 0.06 0.06 0.00
726.40 0.08 0.08 0.00
726.50 0.09 0.09 0.00
726.60 0.10 0.10 0.00
726.70 0.11 0.11 0.00
726.80 0.12 0.12 0.00
726.90 0.12 0.12 0.00
727.00 0.13 0.13 0.00
727.10 0.14 0.14 0.00
727.20 0.15 0.15 0.00
727.30 0.15 0.15 0.00
727.40 0.16 0.16 0.00
727.50 0.16 0.16 0.00
727.60 0.17 0.17 0.00
727.70 0.18 0.18 0.00
727.80 0.27 0.27 0.00
727.90 0.65 0.65 0.00
728.00 1.19 1.19 0.00
728.10 1.86 1.86 0.00
728.20 2.62 2.62 0.00
728.30 3.48 3.48 0.00
728.40 4.42 4.42 0.00
728.50 5.43 5.43 0.00
728.60 6.51 6.51 0.00
728.70 7.65 7.65 0.00
728.80 8.77 8.77 0.00
728.90 9.66 9.66 0.00
729.00 10.45 10.45 0.00
729.10 11.17 11.17 0.00
729.20 11.83 11.83 0.00
729.30 12.46 12.46 0.00
729.40 13.06 13.06 0.00
729.50 13.62 13.62 0.00
729.60 15.40 15.40 0.00
729.70 18.19 18.19 0.00
729.80 21.77 21.77 0.00
729.90 25.76 25.76 0.00
730.00 26.20 26.20 0.00
730.10 26.63 26.63 0.00
730.20 27.06 27.06 0.00
730.30 27.48 27.48 0.00
730.40 27.89 27.89 0.00
730.50 28.30 28.30 0.00
730.60 29.94 28.70 1.24
730.70 32.61 29.10 3.52
730.80 35.99 29.49 6.51
730.90 39.97 29.87 10.09
731.00 44.47 30.25 14.21
731.10 49.45 30.63 18.82
731.20 54.54 31.00 23.54
731.30 59.92 31.37 28.55
Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs)
731.40 65.73 31.73 34.00
731.50 71.84 32.09 39.75
731.60 78.39 32.44 45.95
731.70 85.24 32.79 52.45
731.80 92.17 33.14 59.03
731.90 99.33 33.48 65.85
732.00 106.57 33.82 72.75
Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" '
Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 8 '
Summary for Pond 8P: Outfall 1
Inflow Area = 8.340 ac, 0.00% Impervious, Inflow Depth > 0.87" for 1 yr - 24 hr event '
Inflow = 1.30 cfs @ 12.93 hrs, Volume= 0.604 of
Primary = 1.30 cfs @ 12.93 hrs, Volume= 0.604 af, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Pond 8P: Outfall 1
Hydrograph
Inflow
FE-1 n fi-
Primary
,
N
w
V
3
O
U.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Time (hours)
HYDROCAD HYDROLOGY REPORT
WET DETENTION POND 2
EROSION CONTROL CALCULATIONS
South Tract City Boulevard Development, Charlotte, North Carolina
(5S (6S) (8S)
Pre-dev DA-2 Post-d v DA-2 Post-dev ND DA-2
7P -? 9P
South Tract Wet Pond 2 Outfall 2
Subca Reach on link
Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009
HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment 5S: Pre-dev DA-2
Runoff = 1.46 cfs @ 12.62 hrs, Volume= 0.435 af, Depth> 0.19"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
27.280 60
27.280 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
41.7 Direct Entry, From Spreadsheet
Subcatchment 5S: Pre-dev DA-2
Hydrograph
Runoff
w
3
0
U.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Time (hours)
Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 6S: Post-dev DA -2
Runoff = 71.04 cfs @ 11.96 hrs, Volume= 3.351 af, Depth> 1.60"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
25.110 90
25.110 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 6S: Post-dev DA-2
Hydrograph
-- -------------------- 7 - -- r --- - ----- - - -
Runoff
75 71.04 cfs
..
70 ' _........ - ; ....: .... -... Ghar1otte 24-hr....
65 --------------- - --------- --------------- - -
- - - 1--y ?t r :24--hr----
60 -------
------------------------ ----------------
55 ' Raltlf«-2 r$?
50 R??r?nff Ards-7? 77nw7?,.
Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 8S: Post-dev UND DA-2
Runoff = 1.07 cfs @ 12.49 hrs, Volume= 0.189 af, Depth> 0.38"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
5.930 67
5.930 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
41.7 Direct Entry,
Subcatchment 8S: Post-dev UND DA-2
Hydrograph
® Runoff I
w
0
3
0
LL
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Time (hours)
Southern Tract Pond 2 Charlotte 24-hr 7 yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009
HydroCAD0 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5
Summary for Pond 7P: South Tract Wet Pond 2
Inflow Area = 25.110 ac, 0.00% Impervious, Inflow Depth > 1.60" for 1 yr - 24 hr event
Inflow = 71.04 cfs @ 11.96 hrs, Volume= 3.351 of
Outflow = 0.37 cfs @ 24.00 hrs, Volume= 0.361 af, Atten= 99%, Lag= 722.7 min
Primary = 0.37 cfs @ 24.00 hrs, Volume= 0.361 of
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Peak Elev= 721.89'@ 24.00 hrs Surf.Area= 50,086 sf Storage= 130,204 cf
Plug-Flow detention time= 439.9 min calculated for 0.360 of (11 % of inflow)
Center-of-Mass det. time= 263.1 min ( 1,074.0 - 811.0 )
Volume Invert Avail.Storage Storage Description
#1 719.00' 301,703 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
719.00 38,235 0 0
720.00 44,277 41,256 41,256
721.00 47,329 45,803 87,059
722.00 50,442 48,886 135,945
723.00 53,616 52,029 187,974
724.00 56,850 55,233 243,207
725.00 60,143 58,497 301,703
Device Routing Invert Outlet Devices
#1 Primary 719.00' 24.0" x 147.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 716.00' S= 0.0204'/' Cc= 0.900 n=0.013
#2 Device 1 719.00' 2.9" Vert. Orifice/Grate C= 0.600
#3 Device 1 722.00' 1.50' W x 0.50'H Vert. Orifice/Grate C=0.600
#4 Secondary 723.50' 40.0' long x 13.5' breadth Emergency Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.62 2.66 2.70 2.66 2.65 2.66 2.65 2.63
#5 Device 1 723.60' 14.0' long x 0.5' breadth Grate on Overflow Structure
Head (feet) 0.20 0.40 0.60 0.80 1.00
Coef. (English) 2.80 2.92 3.08 3.30 3.32
Primary OutFlow Max=0.37 cfs @ 24.00 hrs HW=721.89' (Free Discharge)
L1=Culvert (Passes 0.37 cfs of 20.77 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.37 cfs @ 8.01 fps)
3=Orifice/Grate ( Controls 0.00 cfs)
-Grate on Overflow Structure ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=719.00' (Free Discharge)
t4=Emergency Spillway (Controls 0.00 cfs)
Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009
HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 6
Pond 7P: South Tract Wet Pond 2
Hydrograph
u
M
3
c
u
¦ Inflow '
Outflow
i Primary
'
Secondary
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Z1 ZZ Z6 24
Time (hours)
Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009
HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 7
Stage-Discharge for Pond 7P: South Tract Wet Pond 2
Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs)
719.00 0.00 0.00 0.00
719.10 0.02 0.02 0.00
719.20 0.06 0.06 0.00
719.30 0.09 0.09 0.00
719.40 0.12 0.12 0.00
719.50 0.14 0.14 0.00
719.60 0.15 0.15 0.00
719.70 0.17 0.17 0.00
719.80 0.18 0.18 0.00
719.90 0.19 0.19 0.00
720.00 0.21 0.21 0.00
720.10 0.22 0.22 0.00
720.20 0.23 0.23 0.00
720.30 0.24 0.24 0.00
720.40 0.25 0.25 0.00
720.50 0.26 0.26 0.00
720.60 0.27 0.27 0.00
720.70 0.28 0.28 0.00
720.80 0.29 0.29 0.00
720.90 0.29 0.29 0.00
721.00 0.30 0.30 0.00
721.10 0.31 0.31 0.00
721.20 0.32 0.32 0.00
721.30 0.33 0.33 0.00
721.40 0.33 0.33 0.00
721.50 0.34 0.34 0.00
721.60 0.35 0.35 0.00
721.70 0.35 0.35 0.00
721.80 0.36 0.36 0.00
721.90 0.37 0.37 0.00
722.00 0.37 0.37 0.00
722.10 0.53 0.53 0.00
722.20 0.82 0.82 0.00
722.30 1.18 1.18 0.00
722.40 1.62 1.62 0.00
722.50 2.11 2.11 0.00
722.60 2.50 2.50 0.00
722.70 2.81 2.81 0.00
722.80 3.08 3.08 0.00
722.90 3.32 3.32 0.00
723.00 3.55 3.55 0.00
723.10 3.76 3.76 0.00
723.20 3.96 3.96 0.00
723.30 4.14 4.14 0.00
723.40 4.32 4.32 0.00
723.50 4.49 4.49 0.00
723.60 7.97 4.66 3.31
723.70 15.43 6.06 9.37
723.80 25.83 8.47 17.35
723.90 38.61 11.70 26.92
724.00 53.50 15.60 37.90
724.10 70.44 20.25 50.19
724.20 88.36 25.58 62.78
724.30 107.50 31.37 76.13
Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs)
724.40 122.41 31.73 90.68
724.50 138.09 32.09 106.00
724.60 154.96 32.44 122.52
724.70 172.66 32.79 139.87
724.80 190.55 33.14 157.41
724.90 209.07 33.48 175.59
725.00 227.82 33.82 194.00
Southern Tract Pond 2 Charlotte 24-hr 9-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009
HydroCADO 8 50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 8
Summary for Pond 9P: Outfall 2
Inflow Area = 31.040 ac, 0.00% Impervious, Inflow Depth > 0.21" for 1 yr - 24 hr event
Inflow = 1.37 cfs @ 12.50 hrs, Volume= 0.550 of
Primary = 1.37 cfs @ 12.50 hrs, Volume= 0.550 af, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Pond 9P: OutFall 2
Hydrograph
¦ Inflow
® Primary H
w
V
3
O
U.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 1U 1u L1 LL t.5 cw
Time (hours)