20081866 Ver 2_Stormwater Info_20090313

OFFICE USE ONLY
Date Received Fee Paid Permit Number(s)
V2
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality 401/Wetlands Unit
EXPRESS REVIEW PROGRAM STORMWATER MANAGEMENT APPLICATION FORM
This form may be photocopied for use as an original
1. GENERAL INFORMATION
1. APPLICANT'S NAME (specify the name of the corporation, individual, etc. who owns the project):
Crescent Resources, LLC
2. OWNER/SIGNING OFFICIAL'S NAME AND TITLE (person legally responsible for facility and
compliance): David Niekamp, Director of Retail Development
3. OWNER MAILING ADDRESS (for person listed in item 2 above):
400 South Tryon Street
Suite 1300
Charlotte, North Carolina 28285
4. OWNER ADDITIONAL CONTACT INFORMATION:
Phone: [phone] Fax: [phone] Email: [e-mail]
5. PROJECT NAME (subdivision, facility, or establishment name - should be consistent with project name
on plans, specifications, letters, inspection and maintenance agreements, etc.):
North Belgate Multi-Family
6. PROJECT LOCATION:
Street Address: Intersection of McCullough Drive and IKEA Blvd. (Exit 45 off 1-85)
City: Charlotte County: Mecklenburg State: NC Zip Code:
Latitude: 35.3005 N Longitude: 80.7602 W
7. DIRECTIONS TO PROJECT SITE (from nearest major intersection):
Exist off I-85 at Exit 45; East to intersection with McCullough Drive; Right turn on McCullough Drive; Right turn
on exiting road intersection with IKEA Blvd. and McCullough Drive.
8. CONTACT PERSON (who can answer stormwater-related questions about the project):
Name: Beverly Rosenbloom, El Company: Kimley-Horn and Associates, Inc.
Phone: [phone] Fax: [phone] Email: [e-mail]
1/2009 Version 1.1 Page 1 of 5
II. PERMIT INFORMATION
1. THE PROJECT IS (check one): ?X NEW ? A RENEWAL ? A MODIFICATION
2. OTHER JURISDICTIONS:
Which local government(s) has jurisdiction over the project (e.g. Town of Cary or Johnston County)?:
City of Charlotte
3. STORMWATER MANAGEMENT PROGRAM
Check all of the state-approved stormwater management programs (implemented by either the State or
local government) that apply to your project:
? Phase II Post Construction ? Water Supply Watershed ? Neuse or Tar-Pamlico NSW
? Randleman WSWS ? USMP ? Coastal Counties ? HQW ? ORW
4. PERMIT HISTORY (renewal or modification requests must complete this item):
Existing DWQ Permit Number: Date Issued:
5. PROJECT TYPE (check one): ? Low Density* ?X High Density*
* Low Density projects shall be under 24% Impervious with only vegetated stormwater conveyances. A
curb and gutter or pipe system for stormwater conveyance shall result in reclassification of project as
High Density even if below 24%, except when pipes are used for road or driveway crossing purposes.
6. ADDITIONAL PROJECT REQUIREMENTS (check all that apply):
? CAMA Major ?X Sedimentation/Erosion Control ?X NPDES Stormwater
? 404/401 Permit ? Non-404 Jurisdictional Permit ? Other:
Note: Information on required state permits can be obtained by contacting the Customer Service Center at
1-877-623-6748
III. PROJECT INFORMATION
1. STORMWATER TREATMENT METHODS (Describe briefly how stormwater will be treated):
The development will be treated by two wet detention ponds. Storm-water will be collected by a storm-water system
and directed to the ponds.
Important Note: attach a detailed narrative (one to two pages) describing stormwater management for the
project.
2. RIVER BASIN/STREAM INFORMATION
a. Stormwater runoff from this project drains to which River Basin?: Yadkin
b. Nearest named stream: UT to Doby Creek
c. Water quality classification of nearest named stream: C
1/2009 Version 1.1 Page 2 of 5
3. TOTAL PROJECT AREA: 1 26.7 (acres)
4. PROJECT BUILT UPON AREA: 1 53.33%
5. DRAINAGE AREAS (How many drainage areas does the project have?):
Complete the following information for each drainage area. If there are more than two drainage areas in the
project, attach an additional sheet with the information for each area provided in the same format as below.
Basin Information Drainage Area 1 Drainage Area 2
Receiving Stream Name UT to Doby Creek UT to Doby Creek
Receiving Stream Class C C
Drainage Area 9.42 10.97
Existing Impervious* Area --- ---
Proposed Impervious*Area 6.28 7.96
% Impervious* Area (total) 67% 73%
Impervious* Surface Area Determination (Breakdown)
Impervious* Surface Area Drainage Area 1 Drainage Area 2
On-site Buildings
On-site Streets
On-site Parking
On-site Sidewalks
Other on-site
Off-site --- ---
Total: 6.28 Total: 7.96
* Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking
areas, sidewalks, gravel areas, etc.
6. EXPLAIN HOW THE OFF-SITE IMPERVIOUS AREA WAS DERIVED:
IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS
Deed restrictions and protective covenants are required to be recorded for all subdivisions, outparcels and
future development draining to the proposed stormwater management devices prior to the sale of any lot. If
applicable, please complete and submit a copy of the deed restrictions and protective covenants along with
your application.
1/2009 Version 1.1 Page 3 of 5
V. SUPPLEMENT FORMS
1. The applicable stormwater management supplement form(s) listed below must be submitted for each
BMP specified for this project. The most current form(s) located on the 401/wetlands unit website at
http://h2o.enr.state.nc.us/su/bmp forms.htm must be used. Please include both the Design Summary and
the Required Items Checklist along with all required items and supporting design calculations.
(Check the supplement forms that will be required for your project):
? Bioretention Supplement ? Level Spreader/Filter Strip/Restored Buffer
? Dry Detention Supplement Supplement
? Grassed Swale Supplement
? Infiltration Basin Supplement
? Infiltration Trench Supplement
? Sand Filter Supplement
? Stormwater Wetland Supplement
Wet Detention Supplement
VI. SUBMITTAL REQUIREMENTS
Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ).
A complete package includes all of the items listed below. The complete application package should be
submitted to the DWQ Central Office.
1. Please indicate that you have provided the following required information by initialing in the space
provided next to each item.
Initials
• Original and two copies of the Express Review Stormwater Management Application
• Signed and Notarized Inspection and Maintenance Agreement
• Three copies of the applicable Supplement Form(s) for each BMP
• Application processing fee (payable to DWQ)
• Detailed narrative description of stonnwater treatment/management
• Three copies of plans and specifications, including:
? Development/Project name
? Engineer and firm
? Legend
? North arrow
? Scale
? Revision number & date
? Mean high water line
? Dimensioned property/project boundary
? Location map with named streets or NCSR numbers
? Original contours, proposed contours, spot elevations, finished floor elevations
? Details of roads, drainage features, collection systems, and stormwater control measures
? Wetlands and streams delineated, or a note on plans that none exist
? Existing drainage (including off-site), drainage easements, pipe sizes, runoff calculations
? Drainage areas delineated
? Vegetated buffers (where required)
1/2009 Version 1.1 Page 4 of 5
VII. AGENT AUTHORIZATION
If you wish to designate authority to another individual or firm so that they may provide information on your
behalf, please complete this section.
1. DESIGNATED AGENT (individual or firm): Kimley-Horn and Associates, Inc.
2. MAILING ADDRESS:
Contact: Matthew Edwards, PE
4651 Charlotte Park Drive
Suite 300
Charlotte, NC 28217
Phone: [phone] Fax: [phone]
VIII. APPLICANT'S CERTIFICATION
I, (print or type name of person listed in General Information, item 2)
David Niekamp , certify that the information included on this application form is, to
the best of my knowledge, correct and that the project will be constructed in conformance with the approved
plans, that the required deed restrictions and protective covenants (if applicable) will be recorded, and that the
proposed project complies with the requirements of 15A NCAC 2H .1000.
Signature: Date: l,P f
1/2009 Version 1.1 Page 5 of 5
Permit Number: Gx p 0 O- 1 O Lo to Y
(to be provided by DWQ)
Drainage Area Number:
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does ® does not
This system (check one):
? does ? does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/debris is resent. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads 6 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 6 feet in the forebay, the sediment shall
be removed.
BASIN DIAGRAM
(fill in the blanks)
Sediment Removal
Bottom
Permanent Pool Elevation 674
668 Pe ane'
------------------ Volume
667 -ft Min.
Sediment
Storage
FOREBAY
Pool
- - -Sediment Removal Elevation 668 ............ Volume
------ Sediment
Bottom Elevation
MAIN POND
1-ft
Storage
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name:North Belgate Multi-Family
BMP drainage area number:2
Print name:Crescent Resources, LLC - David Niekamp
Title:Director of Retail Development
Address:400 South Tryon Street, Suite 1300, Charlotte, NC 28285
Phone:[phone]/l . 17
r
Signature: AU-41, I
Date: & o
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, YfiY?1 1 - T? a Njotart' Public for the State of
• r . , County of Uv? , do hereby certify that

personally appeared before me this
day of le , ZOO ) n , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My Commission Expires August 17, 2013
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
EX? 08- 186 to V2
DWQ 401/Express Permit Stormwater Applications (Version 1)
DEED RESTRICTIONS AND PROTECTIVE COVENANTS
Deed restrictions and protective covenants are necessary to ensure that the development maintains an "impervious"
area consistent with the design criteria used to size the stormwater control structure. The following italicized deed
restrictions and protective covenants are required to be recorded prior to the sale of any lot for all subdivisions,
outparcels and future development, where lots will be subdivided.
1. The following covenants are intended to ensure ongoing compliance with state Riparian Buffer Authorization
and/or Water Quality General Certification number(s) as issued by the Division of Water
Quality (DWQ) for the project known as
2. The State of North Carolina is made a beneficiary of these covenants to the extent necessary to maintain
compliance with the Riparian Buffer Authorization and/or Water Quality General Certification. These covenants,
therefore, may not be altered, rescinded or deleted without the written consent of the State of North Carolina,
Division of Water Quality.
For drainage area 1, the impervious area percentage shall not exceed
3. (a) Th@-,.suW,.soi.,i au iicrr'v'c^^oc%e i7i4F 2rb'i61b18 EIYEQ 1er- lotb;
square7eept. OR
For drainage area 2, the impervious area percentage shall not exceed
(b) If the proposed impervious amount per lot varies significantly, please provide the following: lot number, lot
size (square feet), and the maximum allowable impervious area (square feet) for each lot as an attachment.
Impervious materials include asphalt, gravel, concrete, brick, stone, slate or similar material but do not include
wood decking or the water surface of swimming pools.
4. Swales shall not be filled in, piped, or altered except as necessary to provide driveway crossing.
5. Impervious area in excess of the permitted amount requires a modified water quality certification prior to
construction.
6 All permitted runoff from outparcels or future development shall be directed into the permitted stormwater control
system. These connections to the stormwater control system shall be performed in a manner that maintains the
integrity and performance of the system as permitted.
7. The approved stormwater treatment facilities, stormwater easements and drainage patterns must be maintained in
perpetuity. Alteration of the drainage system as depicted on the approved plan(s) may not take place without the
concurrence of the Division of Water Quality.
8. These covenants are to run with the land and be binding on all parties claiming under them.
By your signature below, you certify that, prior to the sale of any lot, the deed restrictions and protective covenants for
this project shall?ecoj?ed, and wffinclude all the applicable required items above.
Date: Y-6-09
1, r , a Notary Public in the State of .
ell,
County of Ir O do hereby certify that appeared
before me this the day of M,4P, c 2009 , and acknowledge the due execution of the
foregoin strument, Witne my hand and official seal,
SEAT
ignature ds
P
My commission expires gust 17, 2013 e
MY
Page 1 of 1
yn.
66.10.
72.6%.

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F.x$ bg-18619 v z

Stormwater Management Calculations
Belgate Multi-Family
Development
9@Lr;!;3Owg9o
MAR 1 3 2009
7 i'tANA$ AND STW ATa 9RMW
Prepared for:
Crescent Resources, LLC
400 S. Tryon Street, Suite 1300
Charlotte, North Carolina 28202
© Kimley-Hom and Associates, Inc. 2009
? ? ? Kimley-Horn
and Associates, Inc.

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This document, together with the concepts and designs presented herein, as an instrument of service, is intended only for the specific
purpose and client for which it was prepared. Reuse of and improper reliance on this document without written authorization and
adaptation by Kimley-Horn and Associates, Inc. shall be without liability to Kimley-Horn and Associates, Inc.
1

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BELGATE MULTI-FAMILY DEVELOPMENT
CHARLOTTE, NORTH CAROLINA
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
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February 2009
KHA Ref: 018253029

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
RIPRAP CALCULATIONS
HYDROCAD HYDROLOGY REPORTS
WET POND I
WET POND 2
STORMWATER MANAGEMENT CALCULATIONS i
Belgate Multi-Family Development, Charlotte, NC

r
Background OVERVIEW
This report contains the approach and results of a stormwater analysis conducted for the Belgate Multi-
Family Development. The approximately 24-acre project site is located north of the interchange of
Interstate 85 and City Boulevard in the City of Charlotte (see vicinity map).
Existing Conditions
The existing on-site conditions consist of woods and meadow therefore this ground cover was used in the
analysis. The site topography varies from elevation 760 ft to elevation 660 ft. Site runoff discharges into
an existing stream along the southwest portion of the site. This stream drains to a culvert under I-85.
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 Basins 1 and 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 once the site develops. The 100-year, 24-hour storm event was checked
for 6" of freeboard at the top of bank.
r.

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Results
Pre-development Flow
1- r, 24-hr storm cfs Post-development Flow
1- r, 24-hr storm cfs
DA-1 4.71 2.41
DA-2 4.93 1.49
STORMWA TER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, NC
r 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.

1
1
STORMWA TER MANAGEMENT CALCULATIONS 3
Belgate Multi-Family Development, Charlotte, NC
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Stornwater
0?0 BELGATE VICINITY MAP FIGURE
Kimley-Horn and Associates, inc. MULTI FAMILY NTS+ 1
THIS DOCU1017. TOOETM WITH DE CONCEM AND DEMO PRESENTED NflTEW. AS AN W11MAW OF SERVICE, IS W DDFD ONLY Fort TIE KXWCSE AND WENT FOR WITCH R WAS PREPARED. REUSE
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I n BELGATE SCS SOIL SURVEY FIGURE
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PRE-DEVELOPMENT
WATERSHED MAP
STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina
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WATERSHED MAP
STORMWATER MANAGEMENT CALCULATIONS
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WET POND CALCULATIONS
STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina
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Kimley-Hom
Cu" and Associates, Inc.
WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR Date: 10/16/2008
Revised by: BRR Date: 1/19/2009
Revised by: Date:
Site Information
Sub Area Location: Drainage Area 1
Drainage Area (DA) = 9.42 Acres
Impervious Area (IA) = 6.28 Acres
Percent Impervious (1) = 66.7 %
Required Surface Area
Permanent Pool Depth: 3.25 ft
SA/DA = 3.85 (90% TSS Removal via Pond)
Min Req'd Surface Area = 15798 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) = 0.65 in/in
Storage Volume Required = 22,226 cf (above Permanent Pool)
Forebay Volume = 10,885
Elevations Area (s.f.)
Bank Elevation = 675.00 ft
Top of Pond Elevation = 675.00 ft
Temporary Pool Elevation = 671.40 ft
Forebay Weir = 670.00 ft
Shelf Beginning Elevation = 670.50 ft
Permanent Pool Elevation = 670.00 ft
Shelf Ending Elevation = 669.50 ft
Bottom Elevation = 663.00 ft
Wet Basin Areas/Volumes
Area @ Top of Temporary Pool = 20,847 sf
Area @ Top of Permanent Pool = 16,472 sf
Volume of Temporary Storage = 26,123 cf
Side Slopes of Pond = 3 : 1
Side Slopes of Shelf = 10 : 1
Side Slopes of Pond (below shelf) = 3 : 1
Is Permanent Pool Surface Area Sufficient (yes/no)?
Volume of Storage Provided 26,123 cf
Total Volume Sufficient (yes/no)? Yes
Orifice Size = 2.50 inches
Drawdown Time = 2.29 days
20,847
16,472
(Elevation = 671.40)
(Elevation = 670.00 )
Yes ( 16472 > 15798 ) sf
WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR
Revised by: BRR
Revised by:
Site Information
Date:
Date:
Date:
10/20/2008
1/19/2009
Sub Area Location: Drainage Area 1
Drainage Area (DA) = 9.4 Acres
Impervious Area (IA) = 6.3 Acres
Percent Impervious (1) = 66.7 % (Drainage Area)
Orifice Sizing
Q2 Days = 0.1512 cfs (Flowrate required for a 2 day drawdown)
Q5 Days = 0.0605 cfs (Flowrate required for a 5 day drawdown)
Orifice Size = 2.50 in (Diameter)
Q office = 0.108 cfs
Drawdown Time = 2.80 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
A9= Area of Pipe = 7T/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
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PP- Kimley-Hom
kh- and Associates, Inc.
WET DETENTION BASIN
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR Date: 10/16/2008
Revised by: BRR Date: 1/19/2009
Revised by: Date:
Site Information
Sub Area Location: Drainage Area 2
Drainage Area (DA) = 10.97 Acres
Impervious Area (IA) = 7.96 Acres
Percent Impervious (1) = 72.6 %
Required Surface Area
Permanent Pool Depth: 3.25 ft
SA/DA = 3.95 (90% TSS Removal via Pond)
Min Req'd Surface Area = 18875 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) = 0.70 in/in
Storage Volume Required = 27996 cf (above Permanent Pool)
Elevations Area (s.f.)
Bank Elevation = 679.00 ft
Top of Pond Elevation = 679.00 ft
Temporary Pool Elevation = 676.30 ft 27,100
Forebay Weir = 675.00 ft
Shelf Beginning Elevation = 675.50 ft
Permanent Pool Elevation = 675.00 ft 19,979
Shelf Ending Elevation = 674.50 ft
Bottom Elevation = 667.00 ft
Wet Basin Areas/Volumes
Area @ Top of Temporary Pool = 27100 sf (Elevation = 676.30 )
Area @ Top of Permanent Pool = 19979 sf (Elevation = 675.00 )
Volume of Temporary Storage = 30601 cf
Side Slopes of Pond = 3 : 1
Side Slopes of Shelf = 10 : 1
Side Slopes of Pond (below shelf) = 3 : 1
Is Permanent Pool Surface Area Sufficient (yes/no)? Yes ( 19979 > 18875) sf
Volume of Storage Provided 30601 cf
Total Volume Sufficient (yes/no)? Yes
Orifice Size = 2.50 inches
Drawdown Time = 2.9 days

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Project Information
WET DETENTION BASIN
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR Date: 10/21/2008
Revised by: BRR Date: 1/19/2009
Revised by: Date:
Site Information
Sub Area Location: Drainage Area 2
Drainage Area (DA) = 11.0 Acres
Impervious Area (IA) = 8.0 Acres
Percent Impervious (1) = 72.6 % (Drainage Area)
Orifice Sizing
Qz Days = 0.1771 cfs
Qs Days = 0.0708 cfs
Orifice Size = 2.50 in
Q Office = 0.104 cfs
Drawdown Time = 2.9 days
less than 5 days (yes/no) ? Yes
greater than 2 days (yes/no) ? Yes
(Flowrate required for a 2 day drawdown)
(Flowrate required for a 5 day drawdown)
(Diameter)
Orifice Equation: Q=CAgV(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

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ANTI-FLOTATION DEVICE CALCULATIONS
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STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina
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Can wr?.raan
NCDENR ANTIFLOATATION DEVICE DESIGN CALCULATIONS
(per NCDENR Manual)
Project Information
ProjectName: Belgate Multi-Family North
KHA Project g: 018253029
Designed by BRR Date: 1212009
Revised by: BRR Date: 2232009
Revised by: Date:
Revised by Date:
Drainage Area Information:
Drainage Area (ac) = 9 49
Flow (Q25) (cfs) = 15.9
Storage Dimensions:
Basin Side Slopes LX: 1 ) - 3.0 (3:1 max side slopes)
Storage Depth "R" (ft) = 7.00
Elev tt Area SF Cumulative Volume CF
Top of Basin Elevation 675000 27.758
673.00 23.828 124.336
Temporary Pool Elevation 671.40 20847 68.596
Permanent Pool Elevation 670000 16.472 62473
668.00 11.004 34.997
666.00 7.658 16,335
Bottom of Basin Elevation 663.00 3.232 0
Sizing of Aminotation Block:
Control Structure Length (n) = 48
Control Structure Width (in) = 36
Riser Area (sf) = 12.00 (Check riser geometry vs. area equation)
Volume of Water Displaced (cf) = 84.0
Weight of Water Displaced (lb) = 5,242
Min. Required Weight of Anchor Block (b) = 5,766 (1.1 factor of safety)
Anchor Sae:
Width (I7) = 4.5
Length (m = 4.5
Height (If) = 3.50
Weight of Anchor (to) = 6,2D9 O.K. > Minimum Required Weight
Sizing of Emergency Spillway:
Q2,5 (cis) = 15.9
Q,p (cfs) = 15.9
Water Depth Over Spillway (ft) = 0.5
SpBMay Length (ft) = 20.0 (10 t minimum spillway length, Cw=2.7)
Spillway Crest Elevation (ft) = 673.50 (1 ft min. above sediment storage depth)
Freeboard (ft) = 1.06 (1 t minimum)
Pond 2
Drainage Area Information:
Drainage Area (ac) = 10 97
Flow (Q20 (cfs) = 117
Storage Dimensions:
Basin Side Slopes LX: 1 ) = 3.0 (3:1 max side slopes)
Storage Depth "R" (ft) = 8.00
Elev tt Area SF Cumulative Volume CF
Top of Basin Elevation 779000 33.469
777.00 28.671 143.530
Temporary Pool Elevation 776020 27.100 121.221
Pemwnem Pool Elevation 775.00 19.979 92.974
773.00 15.530 57465
769.00 7.351 11703
Bottom of Basin Elevation 767.00 4.352 0
Sizing of Antiflotation Block:
Control Structure Length (n) = 48
Control Structure Width (in) = 36
Riser Area (sf) - 12.00 (Check riser geometry vs. area equation)
Volume of Water Displaced (cf) = 96.0
Weight of Water Displaced (lb) = 5,990
Min. Required Weight of Anchor Block (lb) = 6,589 (1.1 factor of safety)
Anchor Sae:
Width (It) = 5.0
Length (If) = 5.0
Height M = 3.50
Weight of Anchor (b) = 7,665 O.K. > Minimum Required Weight
Sizing of Emergency Spillway:
025(cfa)- 11.7
0.-, (cfs) = 11.7
Water Depth Over Spillway (ft) = 0.5
Spillway Length (ft) = 15.0 (1 D it minimum spillway length, Cw=2.7)
Spillway Crest Elevation (ft) = 777.50 (1 it min. above sediment storage depth)
Freeboard (t) - 1.D6 (1 It minimum)
Page 1 of 1

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VOLUME AND SURFACE AREA TABLES
I
STORMWATER MANAGEMENT CALCULATIONS
' Belgate Multi-Family Development, Charlotte, North Carolina
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WET DETENTION POND
SUPPLEMENT FORMS
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STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina
I Permit

NCDENR
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.
(to be provided by DWQ)
O?O? WAtFROG
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L PROJECT INFORMATION
Project name Belgate Multi-Family
Contact person Beverly Rosenbloom
Phone number 704-319-7699
Date 2/24/2009
Drainage area number 2
ll. DESIGN INFORMATION
Site Characteristics
Drainage area 477,853 ft2
Impervious area, post-development 346,738 ft2
% impervious 72.56 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
27,997 ft3 OK
30,601 ft3
OK, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1 yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: )-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
ft3
ft3
-ft3
0 ft3
ft3
Y (Y or N)
2.6 in
0.15 (unitless)
0.70 (unitless)
0.12 in/hr OK
4.93 ft3lsec
32.80 ft3lsec
27.87 ft3lsec
676.30 fmsl
674.00 fmsl
fmsl
674.50 fmsl
673.50 fmsl Data not needed for calculation option #1, but OK if provided.
668.00 fmsl
667.00 fmsl Data not needed for calculation option #1, but OK if provided.
1.00 ft
Y (Y or N)
676.3 fmsl OK
Form SW401-Wet Detention Basin-Rev.6-2/20/09 Parts I. & 11. Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
Ill. DESIGN INFORMATION
Surface Areas
Area, temporary pool 27,100 ftZ
Area REQUIRED, permanent pool 18,875 ftZ
SAIDA ratio 3.95 (unitess)
Area PROVIDED, permanent pool, AceR„,,a 19,979 ftZ OK
Area, bottom of 1 Oft vegetated shelf, Abc?_meu 12,514 ftz
Area, sediment cleanout, top elevation (bottom of pond), At,atpd 5,052 ftZ
Volumes
Volume, temporary pool 106,550 ft3 Insufficient. Volume does not agree with data previously entered.
Volume, permanent pool, Vp j)w 68,666 ft3
Volume, forebay (sum of forebays if more than one forebay) 14,530 ft3
Forebay % of permanent pool volume 21.2% % OK
SAIDA Table Data
Design TSS removal 90 %
Coastal SAIDA Table Used? N (Y or N)
Mountain/Piedmont SAIDA Table Used? Y (Y or N)
SAIDA ratio 3.95 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) Y (Y or N)
Volume, permanent pool, Vp,---,d 68,666 ft3 OK
Area provided, permanent pool, Ace,,, 19,979 ftZ OK
Average depth calculated 3.44 It OK
Average depth used in SAIDA, d., (Round to nearest 0.5ft) 3.5 It OK
Calculation option 2 used? (See Figure 10-2b) N (Y or N)
Area provided, permanent pool, Aa- " ftZ
Area, bottom of 1 Oft vegetated shelf, Abo, a a, ftZ
Area, sediment cleanout, top elevation (bottom of pond), AM-pd fe
"Depth" (distance b/w bottom of IN shelf and top of sediment) ft
Average depth calculated ft
Average depth used in SAIDA, d.„ (Round to nearest 0.5ft) ft
Drawdown Calculations
Drawdown through orifice? Y (Y or N)
Diameter of orifice (if circular) 2.50 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (CD) 0.60 (unitless)
Driving head (Ho) 0.73 ft
Drawdown through weir? N (Y or N)
Weir type (unitless)
Coefficient of discharge (C.) (unitless)
Length of weir (L) ft
Driving head (H) ft
Pre-development 1-yr, 24-hr peak flow 4.93 ft3/sec OK
Post-development 1-yr, 24-hr peak flow 1.49 ft3/sec Insufficient post-development peak flow.
Storage volume discharge rate (through discharge orifice or weir) 0.10 ft3/sec
Storage volume drawdown time 2.90 days OK, draws down in 2-5 days.
Drawdown time varvinq from expected value by more than a half day.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 3 :1 OK
Length to width ratio 2.4 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.1 ft OK
Vegetated filter provided? N (Y or N) OK
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 Gravity Pipe
Form SW401-Wet Detention Basin-Rev.6-2/20/09
Parts I. & II. Design Summary, Page 2 of 2

1

1
r,
1
1
1
1

1

Permit No
(to be provided by DWQ)
III. 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.
PARR 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.
Flub C-7 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.
C-7 3. Section view of the wet 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.
CALC BOOK 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
C-3 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
I?l'LIL CALC BOOK 7. The supporting calculations.
I- 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).
LPIL, 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.6-2/20/09 Part III. Required Items Checklist, Page 1 of 1
I Permit No.
(to be provided by DWQ)

NCDENR
1

o=?F W A TF9OG
tip r
STORMWATER MANAGEMENT PERMIT APPLICATION FORM Y
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 Multi-Family
Contact person Beverly Rosenbloom
Phone number 704-319-7699
Date 2124/2009
Drainage area number 1
Ill. DESIGN INFORMATION
Site Characteristics
Drainage area 410,335 ftz
Impervious area, post-development 273,557 ft2
% impervious 66.67 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 22,227 ft3 OK
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: )-yr, 24-hr stone
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
26,123 ft3
OK, volume provided is equal to or in excess of volume required.
to
ft3
ft3
0 ft3
ft3
Y (Y or N)
2.6 in
0.15 (unitless)
0.70 (unitless)
0.12 in/hr OK
4.71 ft3lsec
27.03 ft3lsec
22.32 ft3lsec
671.40 fmsl
670.00 fmsl
fmsl
670.50 fmsl
669.50 fmsl Data not needed for calculation option #1, but OK if provided.
664.00 fmsl
663.00 fmsl Data not needed for calculation option #1, but OK if provided.
1.00 ft
Y (Y or N)
671.4 fmsl OK
Form SW401-Wet Detention Basin-Rev.6-2/20/09 Parts I. & II. Design Summary, Page 1 of 2
I Permit No.
(to be provided by DWQ)

1
1
1

1
1

I

II. DESIGN INFORMATION
Surface Areas
Area, temporary pool 27,100 ft2
Area REQUIRED, permanent pool 18,875 ft2
SAIDA ratio 3.95 (unitless)
Area PROVIDED, permanent pool, Ap.,w 19,979 ft2 OK
Area, bottom of 10ft vegetated shelf, Ab?t_sj1en 12,514 ft2
Area, sediment cleanout, top elevation (bottom of pond), Abot_,M 5,052 ft2
Volumes
Volume, temporary pool 106,550 ft3 Insufficient. Volume does not agree with data previously entered.
Volume, permanent pool, Vp--P , 68,666 ft3
Volume, forebay (sum of forebays if more than one forebay) 14,530 ft3
Forebay % of permanent pool volume 21.2% % OK
SAIDA Table Data
Design TSS removal 90 %
Coastal SAIDA Table Used? N (Y or N)
Mountain/Piedmont SAIDA Table Used? Y (Y or N)
SAIDA ratio 3.95 (unitiess)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) Y (Y or N)
Volume, permanent pool, Vpe- j, , 68,666 ft3 OK
Area provided, permanent pool, Ap---P a 19,979 ft2 OK
Average depth calculated 3.44 It OK
Average depth used in SA/DA, d., (Round to nearest 0.5ft) 3.5 It OK
Calculation option 2 used? (See Figure 10-2b) N (Y or N)
Area provided, permanent pool, A,,,,,_,w ft2
Area, bottom of 1 Oft vegetated shelf, Amts of ft2
Area, sediment cleanout, top elevation (bottom of pond), At,a_ d ft2
"Depth" (distance b/w bottom of 10ft shelf and top of sediment) It
Average depth calculated It
Average depth used in SAIDA, d., (Round to nearest 0.5ft) It
Drawdown Calculations
Drawdown through orifice? Y (Y or N)
Diameter of orifice (if circular) 2.50 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (Go) 0.60 (unitless)
Driving head (Ho) 0.73 It
Drawdown through weir? N (Y or N)
Weir type (unitless)
Coefficient of discharge (C.) (unitless)
Length of weir (L) ft
Driving head (H) It
Pre-development 1-yr, 24-hr peak flow 4.93 ft3/sec OK
Post-development 1-yr, 24-hr peak flow 0.92 ft3/sec OK
Storage volume discharge rate (through discharge orifice or weir) 0.10 ft3/sec
Storage volume drawdown time 2.90 days OK, draws down in 2-5 days.
Drawdown time varvinq from expected value by more than a half day.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 3 :1 OK
Length to width ratio 2.4 :1 OK
Trash rack for overflow i£ orifice? Y (Y or N) OK
Freeboard provided 1.1 ft OK
Vegetated filter provided? N (Y or N) OK
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 Gravity Pipe
Form SW401-Wet Detention Basin-Rev.e-2/20109 Parts 1. & 11. Design Summary, Page 2 of 2

Permit No.
(to be provided by DWQ)
Jill. 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.
13 g . 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.

' 1W C-6 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.
D
8r-- C-6 3. Section view of the wet detention basin (1" = 20' or larger) showing:
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
' - Inlet and outlet structures.
1- 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.
Qn CALC BOOK 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
ux C-3 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 Bas in-Rev.6-2/20/09 Part III. Required Items Checklist, Page 1 of 1

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I

CURVE NUMBER CALCULATIONS
I
STORMWATER MANAGEMENT CALCULATIONS
' Belgate Multi-Family Development, Charlotte, North Carolina

u_I \ Kimley-Hom
C]CF1 and Associates, Inc.
Pre vs. Post Runoff Analysis
Composite Curve Number (CN)
Project Information
Project Name: Belgate Multifamily
KHA Project #: 018253029
Designed by: TDR
Revised by: BRR
Revised by:
Date: 10/16/2008
Date: 1/19/2009
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
Wilkes Woods
Good Condition
C
70
5.67
397
70
T Meadow
Good Condition
C
71
5.68
403
71
11.35 800 70.5

DA-2
OUTFALL 2
Wilkes/Enon Woods
Good Condition
C
70
5.53
387
70

Wilkes/Enon Meadow
Good Condition
C
71
5.53
393
71

Cecil Woods
Good Condition
B
55
0.37
20
55

Cecil Meadow
Good Condition
B
58
0.37
21
58
1
11.80
822
69.6
Total Pre-development Area = 23.15
POST DEVELOPMENT
DA-1 POND 1 - Impervious - 98 6.28 615 98

Enon, Wilkes
Open Space - Good Condition
C
74
3.14
232
-7
74
i 9.42 847.80 90.00
UND DA-1 OUTFALL 1 Wilkes Open Space - Good Condition C 74 1.95 144 74
j 1.95 144.30 74.00
DA-2 POND 2 - Impervious - 98 6.01 589 98
Enon, Wilkes Open Space - Good Condition C 74 2.77 205 74
Cecil Open Space - Good Condition B 61 0.24 15 61
- Roadway - Impervious _ 98 1,95 191 98
i
10.97
999.78
91.14
UND DA-2 OUTFALL 2 Wilkes Open Space - Good Condition C 74 1.14 84 74
1.14 84.36 74.00
Total Post-development Area = 23.48
* 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\Nlulti-family\Stormwater Calculations_Multifamily_2008-1 0-18.xtt;1
' TIME OF CONCENTRATION
' CALCULATIONS
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1
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1
1
STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina

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RIP RAP CALCULATIONS
1
STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina
1
1
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1
1
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1
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i
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Belgate Multi-Family Kimle -Horn and Associates, Inc.
Charlotte, North Carolina Date: 2123/2009
KHA Project #: 018253029 Prepared by: BRR
Checked by:
RIP RAP APRON CALCULATIONS
Per NCDENR Design Manual
Structure: Pond 1 Outfall
Pipe Diameter (in): 24
Slope (%): 1.33 0.0133
Manning (n): 0.013
Radius (in): 12
Pipe Area (sf): 3.14
Wetted
Perimeter Flow Area Hydraulic Flow Velocity
Depth Theta (ft) s Radius Flow GPD) (CFS (fps)
Flowing Full: 24.0 6.283 6.283 3.142 0.500 16,906,982 26.16 8.33
10-year flow from HydroCAD: 10.09 2.822 2.822 1.254 0.444 6,236,813 9.65 7.70
Discharge (Q10) = 9.65
Pipe Diameter (in) = 24
d50 = 0.833 Figure 8.06a
Design Conditions = Assume Minimum Tailwater
Width at Pipe Outlet'Do' (ft) = 6
Length of Apron 'La' (ft) = 12 Figure 8.06a
Width at End of Apron 'W' ft) = 18
Min. Stone Depth (in) = 22.491
Stone Class = Class B
RIP RAP APRON CALCULATIONS
Per NCDENR Design Manual
Structure: Pond 2 Outfall
Pipe Diameter (in): 24
Slope (%): 1.11 0.0111
Manning (n): 0.013
Radius (in): 12
Pipe Area (so: 3.14
Depth Theta
Flowing Full: 24.0 6.283
10-year flow from HydroCAD: 8.50 2.550
Discharge (Q10) = 6.43
Pipe Diameter (in) = 24
d50 = 0.833 Figure 8.06a
Design Conditions = Assume Minimum Tailwater
Width at Pipe Outlet 'Do' (ft) = 6
Length of Apron 'La' (ft) = 12 Figure 8.06a
Width at End of Apron 'W' (ft) = 18
Min. Stone Depth (in) = 22.491
Stone Class = Class B
Wetted
Perimeter Flow Area Hydraulic Flow Velocity
ft (s Radius Flow (GPD (CFS (fps)
6.283 3.142 0.500 15,445,493 23.90 7.61
2.550 0.996 0.391 4,152,746 6.43 6.45

' HYDROCAD HYDROLOGY REPORT
WET POND 1

1
1

r
STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina
r
1
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1
1
1
1
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1
1S
Pre-dev DA-1
Subca Reach on Link
5S (7S
Post-d v DA-1 Post-dev 1 Undetained
41
6P 8P
Multi-Family Wet Pond 1 Outfall 1
Multi-Family North Pond 1 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD®8 50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 2
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: Pre-dev DA-1 Runoff Area=11.350 ac 0.00% Impervious Runoff Depth=0.53"
Tc=25.2 min CN=71 Runoff=4.71 cfs 0.503 of
Subcatchment 5S: Post-dev DA-1 Runoff Area=9.420 ac 0.00% Impervious Runoff Depth=1.60"
Tc=5.0 min CN=90 Runoff=27.03 cfs 1.258 of
Subcatchment 7S: Post-dev 1 - Undetained Runoff Area=1.950 ac 0.00% Impervious Runoff Depth=0.65"
Tc=5.0 min CN=74 Runoff=2.25 cfs 0.106 of
Pond 6P: Multi-Family Wet Pond 1 Peak Elev=671.65' Storage=32,519 cf Inflow=27.03 cfs 1.258 of
Primary=1.41 cfs 1.238 of Secondary=0.00 cfs 0.000 of Outflow=1.41 cfs 1.238 of
Pond 8P: Outfall 1 Inflow=2.41 cfs 1.344 of
Primary=2.41 cfs 1.344 of
Total Runoff Area = 22.720 ac Runoff Volume =1.867 of Average Runoff Depth = 0.99"
100.00% Pervious= 22.720 ac 0.00% Impervious = 0.000 ac
F
1 Multi-Family North Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 1S: Pre-dev DA-1
Runoff = 4.71 cfs @ 12.23 hrs, Volume= 0.503 af, Depth= 0.53"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
' Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
11.350 71 PRE - Woods/Meadow - Good condition HSG C
' 11.350 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

3
0

11

1
1
Runoff

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Multi-Family North Pond 1 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD®8 50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 5S: Post-dev DA-1
Runoff = 27.03 cfs @ 11.96 hrs, Volume= 1.258 af, Depth= 1.60"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
9.420 90 POST - Pond Drainage Area
9.420 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, From spreadsheet
Subcatchment 5S: Post-dev DA-1
Hydrograph
w
0
1
1
1
1
1
1
1
1
1
1
0 5 10 15 20 25 30 35 40 45 50 55 60 eb to to ou oo wu vu
Time (hours)

Multi-Family North Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5
Summary for Subcatchment 7S: Post-dev 1 - Undetained
Runoff = 2.25 cfs @ 11.97 hrs, Volume= 0.106 af, Depth= 0.65'
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area ac CN Description
1.950 74 POST - Undetained Drainaqe Area
1.950 Pervious Area
Tc Length Slope Velocity Capacity Description
' (min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 7S: Post-dev 1 - Undetained
Hydrograph

3
0
U.

11

Runoff

u o 1v io zu 40 su s5 4u 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Multi-Family North Pond 1 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCADO 8 50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 6
Summary for Pond 6P: Multi-Family Wet Pond 1
Inflow Area = 9.420 ac, 0.00% Impervious, Inflow Depth = 1.60" for 1 yr - 24 hr event
Inflow = 27.03 cfs @ 11.96 hrs, Volume= 1.258 of
Outflow = 1.41 cfs @ 12.94 hrs, Volume= 1.238 af, Atten= 95%, Lag= 59.1 min
Primary = 1.41 cfs @ 12.94 hrs, Volume= 1.238 of
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 671.65'@ 12.94 hrs Surf.Area= 21,319 sf Storage= 32,519 cf
Plug-Flow detention time= 1,213.3 min calculated for 1.237 of (98% of inflow)
Center-of-Mass det. time= 1,205.0 min ( 2,016.5 - 811.5 )
Volume Invert Avail Storage Storage Description
#1 670.00' 114,229 cf Custom Stage Data (Prismatic) Listed below
Elevation Su rf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
670.00 16,472 0 0
670.50 19,193 8,916 8,916
671.00 20,125 9,830 18,746
672.00 21,949 21,037 39,783
673.00 23,828 22,889 62,671
674.00 25,765 24,797 87,468
675.00 27,758 26,762 114,229
Device Routing Invert Outlet Devices
#1 Primary 663.00' 24.0" x 75.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 662.00' S= 0.0133 '/' Cc= 0.900 n=0.013
#2 Device 1 670.00' 2.5" Vert. Orifice/Grate C= 0.600
#3 Device 1 671.40' 3.00'W x 0.25' H Vert. Orifice/Grate C= 0.600
#4 Device 1 672.00' 3.00' W x 1.00'H Vert. Orifice/Grate C=0.600
#5 Secondary 673.50' 20.0' long x 5.0' 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 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65
2.67 2.66 2.68 2.70 2.74 2.79 2.88
#6 Primary 673.50' 4.00' W x 3.00' H Vert. Orifice/Grate C=0.600
Primary OutFlow Max=1.44 cfs @ 12.94 hrs HW=671.65' (Free Discharge)
1=Culvert (Passes 1.44 cfs of 41.85 cfs potential flow)
2=OrifcelGrate (Orifice Controls 0.20 cfs @ 6.00 fps)
3=Orifice/Grate (Orifice Controls 1.23 cfs @ 1.65 fps)
-Orifice/Grate ( Controls 0.00 cfs)
-Orifice/Grate ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=670.00' (Free Discharge)
L5=Broad-Crested Rectangular Weir (Controls 0.00 cfs)
1
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1
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1
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1
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1
1
1
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1
1
Multi-Family North Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 7
Pond 6P: Multi-Family Wet Pond 1
Hydrograph

® Inflow
Outflow
Primary
El Secondary
I IV io cu ca Ou so 4u 4b bU bb 60 65 70 75 80 85 90.95 100 105 110 115 120
Time (hours)
Multi-Family North Pond 1 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HvdroCADO 8 50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 8
Summary for Pond 8P: OutFall 1
[40] Hint: Not Described (Outflow= Inflow)
Inflow Area = 11.370 ac, 0.00% Impervious, Inflow Depth > 1.42" for 1 yr - 24 hr event
Inflow = 2.41 cfs @ 11.97 hrs, Volume= 1.344 of
Primary = 2.41 cfs @ 11.97 hrs, Volume= 1.344 af, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Pond 8P: Outfall 1
Hydrograph
® Inflow
Primary
941 r 13 S i
2.41 cfs InfIow Area=11:370: ac
2
w
- ---------------
- - - -
----------
LL
y
O
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
1
1
1
1
1
1
HYDROCAD HYDROLOGY REPORT
WET POND 2
STORMWATER MANAGEMENT CALCULATIONS
Belgate Multi-Family Development, Charlotte, North Carolina
1
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1

9S
Pre-dev DA-2
Subca Reach on Link
10S 13S
Post-d v DA-2 Post-dev 2 Undetained
11 12
Multi-Family Wet Pond 2 Outfall 2

Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCADO 8 50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 2
Time span=0.00-120.00 hrs, dt=0.04 hrs, 3001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 9S: Pre-dev DA-2
Subcatchment 10S: Post-dev DA-2
Runoff Area=11.800 ac 0.00% Impervious Runoff Depth=0.49"
Tc=21.4 min CN=70 Runoff=4.93 cfs 0.486 of
Runoff Area=10.970 ac 0.00% Impervious Runoff Depth=1.68"
Tc=5.0 min CN=91 Runoff=32.80 cfs 1.539 of
Subcatchment 13S: Post-dev 2 - Undetained
Runoff Area=1.140 ac 0.00% Impervious Runoff Depth=0.65"
Tc=5.0 min CN=74 Runoff=1.31 cfs 0.062 of

117

1
J
Pond 11 P: Multi-Family Wet Pond 2 Peak Elev=676.31' Storage=56,125 cf Inflow=32.80 cfs 1.539 of '
Primary=0.28 cfs 1.442 of Secondary=0.00 cfs 0.000 of Outflow=0.28 cfs 1.442 of
Pond 12P: Outfall 2
Inflow=1.49 cfs 1.504 of '
Primary=1.49 cfs 1.504 of
Total Runoff Area = 23.910 ac Runoff Volume = 2.087 of Average Runoff Depth = 1.05"
100.00% Pervious= 23.910 ac 0.00% Impervious = 0.000 ac
L

1
' Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 3
' Summary for Subcatchment 9S: Pre-dev DA-2
' Runoff = 4.93 cfs @ 12.18 hrs, Volume= 0.486 af, Depth= 0.49"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
11.800 70 PRE - Woods/Meadow - Good condition HSG C
' 11.800 Pervious Area
Tc Length Slope Velocity Capacity Description
' (min) (feet) (ft/ft) (ft/sec) (cfs)
21.4 Direct Entry, From spreadsheet
Subcatchment 9S: Pre-dev DA-2
Hydrograph
1
n

3
0
U.
r

1-1
Runoff

U 0 I0 io Z0 15 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 10S: Post-dev DA-2
Runoff = 32.80 cfs @ 11.96 hrs, Volume= 1.539 af, Depth= 1.68"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
' 10.970 91 POST - Pond Drainage Area
10.970 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, From spreadsheet
Subcatchment 10S: Post-dev DA-2
Hydrograph
3
0
U.
o '
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1
1
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1
1
1
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 11u 115 1Z0
Time (hours)

Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5
Summary for Subcatchment 13S: Post-dev 2 - Undetained
Runoff = 1.31 cfs @ 11.97 hrs, Volume= 0.062 af, Depth= 0.65'
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Area (ac) CN Description
1.140 74 POST - Undetained Drainage Area
1.140 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
w

3
0
LL

. 6 .. jg .. 8,6..85.. 9 . .
0 5 10 .. 1,? .. 20 25 36 A 46 45 ' 50 j
0 95 100 105 1'10-1'1'5-1'2O
Time (hours
1
1
1
1
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD® 8.50 s/n 005123 @2007 HydmCAD Software Solutions LLC Paae 6
Summary for Pond 11P: Multi-Family Wet Pond 2
Inflow Area = 10.970 ac, 0.00% Impervious, Inflow Depth = 1.68" for 1 yr - 24 hr event
Inflow = 32.80 cfs @ 11.96 hrs, Volume= 1.539 of
Outflow = 0.28 cfs @ 24.00 hrs, Volume= 1.442 af, Atten= 99%, Lag= 722.8 min
Primary = 0.28 cfs @ 24.00 hrs, Volume= 1.442 of
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Peak Elev= 676.31'@ 24.00 hrs Surf.Area= 27,138 sf Storage= 56,125 cf
Plug-Flow detention time= 2,467.7 min calculated for 1.442 of (94% of inflow)
Center-of-Mass det. time= 2,432.6 min ( 3,239.3 - 806.8 )
Volume Invert Avail Storage Storage Description
#1 674.00' 137,143 cf Custom Stage Data (Prismatic) Listed below
Elevation Su rf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
674.00 19,979 0 0
675.00 24,296 22,138 22,138
676.00 26,441 25,369 47,506
677.00 28,671 27,556 75,062
678.00 31,011 29,841 104,903
679.00 33,469 32,240 137,143
Device Routing Invert Outlet Devices
#1 Primary 667.00' 24.0" x 90.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 666.00' S= 0.0111 '/' Cc= 0.900 n= 0.013
#2 Device 1 674.00' 2.5" Vert. Orifice/Grate C= 0.600
#3 Device 1 676.30' 3.50' W x 0.50'H Vert. Orifice/Grate C=0.600
#4 Device 1 677.00' 3.50' W x 1.00'H Vert. Orifice/Grate C=0.600
#5 Secondary 677.50' 15.0' long x 5.0' 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 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65
2.67 2.66 2.68 2.70 2.74 2.79 2.88
#6 Device 1 677.50' 4.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C=0.600
Primary OutFlow Max=0.26 cfs @ 24.00 hrs HW=676.31' (Free Discharge)
L1=Culvert (Passes 0.26 cfs of 43.61 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.24 cfs @ 7.16 fps)
3=Orifice/Grate (Orifice Controls 0.02 cfs @ 0.36 fps)
-Orifice/Grate ( Controls 0.00 cfs)
-Orifice/Grate ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=674.00' (Free Discharge)
t--5=Broad-Crested Rectangular Weir (Controls 0.00 cfs)
11
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1
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Pam
Pond 11P: Multi-Family Wet Pond 2
Hydrograph
i
Inflow
Outflow
Primary
! Secondary
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Mulit-Family North Pond 2 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58"
Prepared by Kimley-Horn and Associates, Inc. Printed 2/12/2009
HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 8
Summary for Pond 12P: Outfall 2
[40] Hint: Not Described (Outflow= Inflow)
Inflow Area = 12.110 ac, 0.00% Impervious, Inflow Depth > 1.49" for 1 yr - 24 hr event
Inflow = 1.49 cfs @ 11.97 hrs, Volume= 1.504 of
Primary = 1.49 cfs @ 11.97 hrs, Volume= 1.504 af, Atten= 0%, Lag= 0.0 min
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.04 hrs
Pond 12P: Outfall 2
Hydrograph
® Inflow
Primary
N
w
V
3
O
LL
., ?„ ?., ?., ? .. .... .... .... ... .... Time (hours) - - --
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does ? does not incorporate a vegetated filter at the outlet.
This system (check one):
? does ? does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/debris is resent. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
Swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads 6 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 5 feet in the forebay, the sediment shall
be removed.
BASIN DIAGRAM
ill in the blanks)
0 Permanent Pool Elevation 670
Sediment Removal .665 YPe anen Po ol
- - - - - - - - - - - - - - - olume Sediment Removal Elevation 664 Volume
Bottom Elevatio 664 Min.
------------------------------ ------------ ----ediment Bottom Elevation 663 1-ft n
Storage Sedimet
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4

Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name:North Belgate Multi-Family
BMP drainage area number: l
Print name:Crescent Resources, LLC - David Niekamp
Title:Director of Retail Development
Address:400 South Tryon Street, Suite 1300, Charlotte NC 28285
Phone:[phone],
Signature Date: Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
a Notary Public for the State of
County of C? , do hereby certify that
Ah-VtO o )') personally appeared before me this
day of )4144- 1U? , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires
W CotnMiSSW Expires August 17, 2013
Form SW401-Wet Detention Basin O&M-Rev.4
Page 4 of 4