20072082 Ver 1_More Info Received_20080606

0'1 - - -o03 2,
THE JOHN R McADAMS COMPANY, INC.
LETTER OF TRANSMITTAL
To: Joseph Gyamfi
NC Division of Water Qualitv
401 Oversight & Express Permitting Unit
2331 Crabtree Blvd, Suite 250
Raleiah. NC 27604
Re: Highway 29 Project (DWQ #07-2082)
Charlotte. NC
am sending you the following item(s):
Date: June 5, 2008
** FEDERAL EXPRESS **
Job No.: GWH-06040
COPIES DATE NO. DESCRIPTION
3 5/5/08 Request for More Information
3 6/5/08 Letter & attachments (original & 2 copies)
3 6/5/08 Stormwater Impact Analysis
3 6/5/08 Stormwater M mt Facility Deis n Plans

These are transmitted as checked below:
? As requested
® For approval
? For review and comment
Remarks:
?? , I
? For your use ?uN 6 2008
? i Auld
DS AND S' M'NAER {? 0011
F-1 V45T ?
Copy to:
Signed:
t
Jennifer C. Dia I
Assoc Eng, SW & Environmental
FOR INTERNAL USE ONLY
? Copy Letter of Transmittal Only to File
® Copy Entire Document to File
ENGINEERS • PLANNERS • SURVEYORS • ENVIRONMENTAL
RESEARCH TRIANGLE PARK • CHARLOTTE ¦ WILMINGTON
800-733-5646 ¦ www.johnrmcadams.com
[JEcoEngineering
A division of The John R. McAdams Company, Inc.
June 5, 2008
Mr. Joseph Gyamfi
North Carolina Division of Water Quality
401 Oversight/Express Review Permitting
2321 Crabtree Boulevard, Suite 250
Raleigh, North Carolina 27604
Re: Highway 29 Project (DWQ #07-2082)
Response to Comments dated May 5, 2008
GWH-06040
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Dear Mr. Gyamfi:
Below please find our response to your comments for your review on the
above referenced project:
Comment 1: Please clearly delineate the drainage area to each BMP (one
color drainage map, and one copy shall suffice). Please note that
stormwater runoff from the entire project site shall be treated to
achieve 85% TSS removal prior to leaving the site or discharge
to state waters. Runoff generated onsite shall not bypass the
stormwater treatment systems.
Response 1: A color version of the post development watershed map WS-2
has been provided.
Comment 2: Please redesign all proposed BMPs (Wet Detentions Ponds) in
accordance with the most current version of the NC Division of
Water Quality Stormwater Best Management Practices Manual.
Response 2: The design of the BMPs has been updated to most current
version of the NC DWQ Stormwater BMP Manual.
Comment 3: Please complete and submit the most current version of the BMP
Supplement Form for each BMP along with all requested
information in the Required Items Checklist. The BMP Manual
and the Supplement Forms are available at
http://h2o.enr.state.nc.us/su/bmp forms.htm.
Research Triangle Park, NC
Post Office Box 14005
Research Triangle Park,
North Carolina 27709
2905 Meridian Parkway
Durham, North Carolina 27713
800-733-5545
919-287-4262
919-351-2269 Fax
Response 3: Included in the resubmittal are revised BMP Supplements for
the wet ponds using the most current version (Version 4) from
the DWQ website.
Comment 4: Please pay particular attention to the Major Design Elements
listed on page 10-2 of the BMP Manual.
www.ecoengccom I Design Services Focused On Client Success
EcoEngineering
A division of The John R. McAdams Company, Inc.
Mr. Joseph Gyamfi
June 5, 2008
GWH-06040
Page 2
Response 4: In order to bring the design of the BMPs up to the most
current NC DWQ Stormwater BMP Manual standards, the
BMPs were updated to have the Major Design Elements listed
in the Manual incorporated into their design.
Comment 5: Also, please maximize the length of the flow path between the
inlets and the outlets as much as possible to avoid stormwater
flow short-circuiting. A flow path length to width ration of 3:1 is
recommended. Baffles extending above the temporary pool
levels may be used where there are site constraints.
Response 5: Every effort to avoid stormwater flow short-circuiting has been
made. Please refer to the enclosed exhibits.
Comment 6: For each BMP, please provide the BMP outlet discharge and
velocity calculations for the 10-year storm (Q10, and V10).
Exiting velocity from wet pond 1 in particular must be non-
erosive (less than 2ft/s) since it discharges directly to a
wetland. Please also include photos of areas downslope of the
dissipater pads.
Response 6: The BMP outlet discharge and velocity calculations have been
included in this resubmittal. Please note that the proposed
dissipater pads are much greater than the minimum required
to lessen erosive outlet velocity. Also included in this
resubmittal are pictures downstream of the of the proposed
outlet dissipater pads.
Consideration of this response is greatly appreciated. If you should have any
questions or require additional information, please do not hesitate to contact
me at [phone].
Sincerely,
E JOH CADAMS COMPANY, INC.
J ifer C. i
sociate ject Engineer
Stormwater and Environmental Department
Enclosures
?O?oF w H r?9?G
r-
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A ?
mvcnael v. basicy, UUvcrnor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Colcen Sullins, Director
Ltj (J ?1?/ ? Division of Water Quality
JUN 6 211?? May 5, 2008
OENR - Wru r; (?J:' , ,
W.WDS AND STORMWATER ORANC,4
CERTIFIED MAIL: RETURN RECEIPT REQUESTED
Gateway Homes, LLC
Attn: Mr. Dave Ransenberg
11121 Carmel Commons Boulevard, Suite 350
Charlotte, NC 28226
Subject Property: Highway 29 Project
Mallard Creek [030711, 13-17-5, C]
DWQ Project # 07-2082
Mecklenburg County
MAY - 7 00&

4iol
REQUEST FOR MORE INFORMATION: STORMWATER MANAGEMENT PLAN
Dear Mr. Ransenberg:
On January 31, 2008, the Division of Water Quality (DWQ) issued a 401 Water Quality Certification with
additional conditions to fill or otherwise impact 288 linear feet of stream in order to construct the above
named project. In order to meet Condition 6 of the 401 Certification for this project, a stormwater
management plan, dated August 8, 2007 and revised on April 18, 2008, signed and sealed on April 22, 2008
by Mr. James W. Caldwell, P.E., of John R McAdams Co., Inc was received by the DWQ on April 28,
2008. The DWQ has determined that your stormwater management plan was incomplete as discussed
below.
Additional Information Requested:
1. Please clearly delineate the drainage area to each BMP (one color drainage map, and one copy
shall suffice). Please note that stormwater runoff from the entire project site shall be treated to
achieve 85% TSS removal prior to leaving the site or discharge to state waters. Runoff generated
onsite shall not bypass the stormwater treatment systems.
2. Please redesign all proposed BMPs (Wet Detentions Ponds) in accordance with the most current
version of the NC Division of Water Quality Stormwater Best Management Practices Manual.
3. Please complete and submit the most current version of the BMP Supplement Form for each BMP
along with all requested information in the Required Items Checklist. The BMP Manual and the
Supplement Forms are available at http•//h2o enr state ne us/su/bmn forms htm
4, Please pay particular attention to the Major Design Elements listed on page 10-2 of the BMP
Manual.
t?` hC ng
401 Oversight/Expross Revitw Ptrtnitting Unit 1650 Mail Service Center, Raloigh, North Carding 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh North Carolina 27604
Phone: [phone] / FAX [phone] / hQa nd: (W7/moo enr state.ne/moo enr state.nencwctlands
An Equal Opportunity/Affirmative Action Employer- SW* Recycled/l W- Post Consumer Paper
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Page 2 of 2
May 5, 2008
5. Also, please maximize the length of the flow path between the inlets and the outlets as much as
possible to avoid stormwater flow short-circuiting. A flow path length to width ratio of 3:1 is
recommended. Baffles extending above the temporary pool levels may be used where there are
site constraints.
6. For each BMP, please provide the BMP outlet discharge and velocity calculations for the 10-year
storm (Qlo, and Vlo). Exiting velocity from wet pond 1 in particular must be non-erosive (less
than 2ft/s) since it discharges directly to a wetland. Please also include photos of areas downslope
of the dissipater pads.
The DWQ will require the above additional information to finalize review of the stormwater
management plan for the subject property. Please provide the following information so that we may
continue to review your project.
This letter only addresses the stormwater application review and does not authorize any impacts to
wetlands or waters of the state. Please be aware the stormwater management plans must be approved by
this office before the impacts specified in your 401 Certification occur. You are welcome to contact me
at 919-733-1786 if you have questions or would like to set up a meeting.
Sincerely, 4W
Cyndi Karoly, Supervisor
AIO1 Oversight/Express Review Permitting Unit
CBIUjg
cc: USACE Asheville Regulatory Field Office
Alan Johnson, DWQ Mooresville Regional Office
James Caldwell, P.E., The John R McAdams Co., Inc. 2905 Meridian Pkwy, Durham, NC 28226
File Copy
Central Files
Filename; 072482111gbway29Projeet(Meeklenburq) SW Noldl.doe
Permit No. 07-2082
(to be provided by DWQ)
o??p W A T??OG

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_
NCDEHt y
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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 lllJ must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Highway 29 Project
Contact person James W. Caldwell
Phone number [phone]
Date 5/22/2008
Drainage area number To Pond #1
11. DESIGN INFORMATION
Site Characteristics
Drainage area 658,191.60 fe
Impervious area 342,817.20 fe
% impervious 52.08 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 23,204.00 ft3
Volume provided 102,107.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth N/A in
Pre-development 1-yr, 24-hr runoff N/A ft3
Post-development 1-yr, 24-hr runoff N/A ft3
Minimum volume required #VALUE! ft3
Volume provided NIA ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth N/A (See Note 1) in
Rational C, pre-development N/A (unitless)
Rational C, post-development N/A (unitless)
Rainfall intensity: 1-yr, 24-hr storm N/A in/hr
Pre-development 1-yr, 24-hr peak flow N/A ft3/sec
Post-development 1-yr, 24-hr peak flow WA ft3/sec
Pre/Post 1-yr, 24-hr peak flow control #VALUE! felsec
Basin Elevations
Basin bottom elevation 584.00 ft
Sediment cleanout elevation 585.25 ft
Bottom of shelf elevation 588.50 ft
Permanent pool elevation 589.00 ft
SHWT elevation N/A (See Note 2) ft
Top of shelf elevation 589.50 ft
Temporary pool elevation 590.31 ft
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 3
Permit No. 07-2082
(to be provided by DWQ)
11. DESIGN INFORMATION
Volume and Surface Area Calculations
SA/DA ratio 2.12 (unitless)
Surface area at the bottom of shelf 12,660.00 fe
Volume at the bottom of shelf 38,475.00 ft3
Permanent pool, surface area required 13,970.00 fe
Permanent pool, surface area provided 15,237.00 fe OK
Permanent pool volume 46,092.00 f3
Average depth for SA/DA tables 3.03 ft OK
Surface area at the top of shelf 18,341.00 fe
Volume at the top of shelf 53,339.00 ft3
Forebay volume 9,009.00 ft3
Forebay % of permanent pool volume 19.55 % OK
Temporary pool, surface area provided 20,355.00 fe
Drawdown Calculations
Treatment volume drawdown time 2.04 days OK
Treatment volume discharge rate 0.18 ft3/s
Pre-development 1-yr, 24-hr discharge N/A ft3/s OK
Post-development 1-yr, 24-hr discharge N/A ft3/s OK
Diameter of orifice 2.5 in
Design TSS removal 85 %
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 3.40 :1 OK
Length to width ratio 9.50 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.00 ft OK
Vegetated filter provided? N (See Note 3) (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 8" plug valve (may require pumping for full drainage)
Notes
1-Peak flow attenuation is not required for compliance with the 401 Water
Quality Certification but the City of Charlotte requires peak flow
attenuation for the 2- and 10-year storm events. Please refer to the
design report for detailed calculations.
2-The pond is situated near the existing stream on site so that the
permanent pool is as close to the SHWT as possible.
3-The existing riparian buffer provides the vegetative filter at the
outlet of the pond. Please refer to the pictures provided.
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 3
Permit No. 07-2082
(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.
JWC WS-2 1. Plans (1" 50' or larger) of the entire site showing:
SW-1A 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.
JWC SW-1A 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
SW-1B 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.
N/A 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.
JWC SW-1A 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.
JWC see report 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
JWC SW-1A 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
JWC see report 7. The supporting calculations.
JWC attached 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
N/A 9. A copy of the deed restrictions (if required).
JWC see report 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 3 of 3
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 1
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. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.3 Page 1 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 1
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.3 Page 2 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 1
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.
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 3.75 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 3.75 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 589.00
Sediment Removal
585.25
---------------
584.00
Volume
-ft Min.
Sediment
Storage
Pool
------Sediment Removal Elevation 585.25---------- Volume
-----
Bottom
FOREBAY
Bottom Elevation 584.00 1 1-ft
MAIN POND
Storage
Form SW401-Wet Detention Basin O&M-Rev.3 Page 3 of 4
Permit Number: 0 7- 2 0 8 2
(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: Highway 29 Project
BMP drainage area number: Pond #1
Print name: Mr. Dave
Title: Member Manager / President
Address: 11121 Caramel Commons Boulevard, Suite 350, Charlotte, NC 28266
Phon
Signa
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
r
County of , do hereby certify that
aW-aO L personally appeared before me this ztrcle
day of l fi/? ,dQQ?'; and acknowledge the due execution of the
wet detention basin maintenance requirements. Witness my hand and official
seal,

ca
Z A!%& - IJBL%c ;e
0
SEAL
My commission expiresZk'G Z Z 2e13
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4
w \1 s \ , \\
\ WET POND 1 ??OUTLET ??? ? ??? O •? V \ \ ? ?
\ FLOW LENGTH TO WIDTH RATIO APPROX. # 10% OF DA\? \ \ ?\ \
OUTLET #1 = 3.4:1 \ \ \ \ \\ ?? \
OUTLET #2 = 5.7:1 \ \ \ \ \ `\\ ;, \?\ \ ??\ \ \\
\\ \ \ \ \ \ OUTLET #1 FLOW LENGTH PATH
'w 1 A \ \ V LENGTH = 148'
1XI
\\ \ \ I \ \ AVG FLOW WIDTH ? 43's, l
\ \ III I v v/ I ??:?? i?"Kk
\ v 11 1 I I I I 11 1 \ I ?? ???
1\ 1 1 1 I I I I I III I I I ?/ ?? ' ???
I 1 1 \
10' AQUATIC SHELF 10:1
I // / I 1
FROM EL 588.5 TO EL 589.5 I I / `
// III I I I / // // I I I I
/ I II I //// / / I I TOP OF DAM EL 596.0'\\
/ I I I II II / I 10' MIN?•
/ I I I I I /// / I .\
// / I I / \
NORMAL POOL = EL 589.0 / / II I I I \?
SA = 15,237 SQ FT I \ ( ( II I I I \
SA REQ. = 13,970 SQ FT II I I I \
I I
I I \\ % I ? 11 \\\ /I I
1 I v
?\ I\ I ?` / \\\ AVG FLOW WIDTH 48 \C''`
I I I 1 \ I II \ \ II \\\ 1 ?_ .?
I
I / / I I I I I \ II \\\\ OUTLET #2 FLOW LENGTH PATH-
LENGTH = 273' / ^ f\
OUTLET / / I I \ I I #
\AAPPROX.90% OF DAy
`'G 'APHIC SCALE
50 0 25 50 10 -------- 5N.3.00_ -
S 7\
1 inch = 50 ft. -
PROJECT NO. GWH-06040
® HIGHWAY 29 ATHE JOHN McADAMS
FI GWH06040-WS2.DWG COMPANY, I NC.
a ENGINEERS/PLANNERS/SURVEYORS
SALE: AS NOTED CHARLOTTE, NORTH CAROLINA RESEARCH TRIANGLE PARK, NC
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4 DATE: POND #1 GRADING EXHIBIT P.O. BOX 14005 ZIP 27709-4005
05-19-2008 [phone]
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Pond #1 - Natural Vegetated Buffer at Outlet
Pond #1 -Natural Vegetated Buffer at Outlet
Highway 29
GWH-06040
Wet Pond #1 Dissipator Calculations
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs : 14.01 Flow depth (ft) = 1.12
slope S in %: 0.50% Outlet velocity (fps) = 5.817
pipe diameter D in in.: 36
Manning number n : 0.013
NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft) 3.00
Outlet velocity (fps) 5.82
Apron length (ft) 18.00
AVG DIAM STONE
(inches) CLASS
3 A
» 6 B
13 Bor1
23 2
THICKNESS
(inches)
9
22
22
27
CALCULATION:
Minimum TW Conditions: W = Do + La
=3'+18'
=21 ft
J.C. Diaz, El
6/2/2008
CONCLUSION:
MINIMUM REQUIRED: NCDOT CLASS `B' RIP RAP
18'L x 2 PW x 22" THK
PROPOSED: NCDOT CLASS `B' RIP RAP
27'L x 20'W x 22" THK
DISSIPATOR
Permit No. 07-2082
(to be provided by DWQ)
OF W A TF?
d? OP
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HCDENR °
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 lll) must be printed, filled out and submitted along with all of the required information.
L PROJECT INFORMATION
Project name Highway 29 Project
Contact person James W. Caldwell
Phone number [phone]
Date 5/22/2008
Drainage area number To Pond #2
II. DESIGN INFORMATION
Site Characteristics
Drainage area 522,720.00 ft2
Impervious area 312,760.80 ft2
% impervious 59.83 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 21,020.00 ft3
Volume provided 28,080.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth NIA in
Pre-development 1-yr, 24-hr runoff N/A ft3
Post-development 1-yr, 24-hr runoff N/A ft3
Minimum volume required #VALUE! ft3
Volume provided NIA ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth N/A (See Note 1) in
Rational C, pre-development NIA (unitless)
Rational C, post-development N/A (unitless)
Rainfall intensity: 1-yr, 24-hr storm N/A in/hr
Pre-development 1-yr, 24-hr peak flow N/A ft3lsec
Post-development 1-yr, 24-hr peak flow NIA ft3lsec
Pre/Post 1-yr, 24-hr peak flow control #VALUE! ft3lsec
Basin Elevations
Basin bottom elevation 597.00 ft
Sediment cleanout elevation 598.75 ft
Bottom of shelf elevation 603.50 ft
Permanent pool elevation 604.00 ft
SHWT elevation N/A (See Note 2) ft
Top of shelf elevation 604.50 ft
Temporary pool elevation 605.56 ft
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 2
Permit No. 07-2082
(to be provided by DWQ)
If. DESIGN INFORMATION
Volume and Surface Area Calculations
SA/DA ratio 2.15 (unitless)
Surface area at the bottom of shelf 9,879.00 ft2
Volume at the bottom of shelf 34,351.00 ft3
Permanent pool, surface area required 11,256.00 ft
Permanent pool, surface area provided 11,329.00 ft2 OK
Permanent pool volume 41,380.00 ft3
Average depth for SA/DA tables 3.65 ft OK
Surface area at the top of shelf 12,940.00 ft2
Volume at the top of shelf 47,003.00 ft3
Forebay volume 8,433.00 ft3
Forebay % of permanent pool volume 20.38 % OK
Temporary pool, surface area provided 15,098.00 ft2
Drawdown Calculations
Treatment volume drawdown time 2.58 days OK
Treatment volume discharge rate 0.13 ft3ls
Pre-development 1-yr, 24-hr discharge NIA ft3ls OK
Post-development 1-yr, 24-hr discharge NIA ft3ls OK
A rl d i t i n n n I I nfn rm n t i n n
Diameter of orifice 2 in
Design TSS removal 85 %
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 3.40 :1 OK
Length to width ratio 3.40 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.00 ft OK
Vegetated filter provided? N (See Note 3) (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 8" plug valve (may require pumping for complete drainage)
Notes
1-Peak flow attenuation is not required for compliance with the 401 Water
Quality Certification but the City of Charlotte requires peak flow
attenuation for the 2- and 10-year storm events. Please refer to the
design report for detailed calculations.
2-The pond is situated near the existing stream on site so that the
permanent pool is as close to the SHWT as possible.
3-The existing riparian buffer provides the vegetative filter at the
outlet of the pond. Please refer to the pictures provided.
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
Permit No
(to be provided by DWQ)
07-2082
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.
JWC WS-2 1. Plans (1" - 50' or larger) of the entire site showing:
SW-2A 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.
JWC SW-2A 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
SW- 21B 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.
N/A 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.
JWC SW-2A 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.
JWC see report 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
JWC SW-2A 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
JWC see report 7. The supporting calculations.
JWC attached 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
N/A 9. A copy of the deed restrictions (if required).
JWC see report 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 3 of 3
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 2
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 roblem: 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.3 Page 1 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 2
BMP element: Potential problem: How I will rernediate 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.3 Page 2 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 2
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.
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 5.25 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 4.50 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
Sediment Removal
Bottom Elev
0 Permanent Pool Elevation 604.00
599.50 Pe manen Pool
-------------- -- Volume Sediment Removal Elevation 598.75 Volume
----------------------------------------------
5 8.00 -ft Min. ----
Sediment Bottom Elevation 597.00 1-ft n
Storage Sedimer
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev. 3 Page 3 of 4
Permit Number: 0 7- 2 0 8 2
(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: Highway 29 Project
BMP drainage area number: Pond #2
Print name: Mr. Dave Ransenberg
Title: Member Manager / President
Address: 11121 Caramel Commons Boulevard Suite 350, Charlotte NC 28266
Phone: [phone]
Signature:
Date: (0 17-16
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,????• , a Notary Public for the State of
of ?i CCL? do hereby certify that
personally appeared before me this 244-1,
day of and acknowledge the due execution of the
forgoi g wet detention basin maintenance requirements. Witness my hand and official
seal,
i
v,vA,
s
? Y
C) AUGOCI
1111,818810166666
SEAL
0
Z7
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4
\ - _OUTLET #1
APPROX. 5% OF DA
%
\ OUTLET #1 FLOW LENGTH PATH x\ \ \ 14' \ \ \ \
/ _ - LENGTH = 175' \\\?\?O \ \
OUTLET #2 FLOW LENGTH PATH \ \ \
LENGTH = 205'
\ \ \ \ \\ \\\ ( \ \ \ \ \
\ \ \ I
\N 0
\ \ \ \ \ \ \ \ \ \ \ \
\\ \ \ \\ \\ \\\ \ \ \
VG FLOW WIDTH = 54.5' \ \
\
a
In
00
0
0
N
O
N
U
m
E
D
m
3
m
\\ \\ \ \ NORMAL POOL = EL 604.0-
\\, \ \\ SA = 11,329 SQ FT
AVG FLOW WIDTH = 52' SA REQ. = 11,146 SQ FT
\\\?\\\ I ' II II I
W. XX\
I
- ? I I
? II I
l

/ OUTLET #2
,APPROX. 95% OF DA
GRAPHIC SCALE WET POND # 2
30 0 15 30 60 FLOW LENGTH TO WIDTH RATIO
OUTLET #1 = 3.4:1
OUTLET #2 = 3.8:1
I inch = 30 ft.
0

® PROJECT NO. GWH-06040 HIGHWAY 29 THE
JOHN R.
McADAMS

n
FILENAME:
GWH 06040-WS2.DWG COMPANY,
INC.

a
SCALE:
C
NOR'T'H CAROLINA ENGINEERS PLANNERS SURVEYORS
/ /
AS NOTED , RESEARCH TRIANGLE PARK, NC
DATE: POND #2 GRADING EXHIBIT P.O. BOX 14005 ZIP 27709-4005
05-19-2008 [phone]
x

Pond #2 - Natural Vegetated Buffer at Outlet
Pond #2 - Natural Vegetated Buffer at Outlet
Highway 29
GWH-06040
Wet Pond #2 Dissipator Calculations
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs : 20.83 Flow depth (ft) = 1.39
slope S in %: 0.50% Outlet velocity (fps) = 6.471
pipe diameter D in in.: 36
Manning number n : 0.013
NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft)
Outlet velocity (fp
Apron length (ft)
AVG DIAM STONE
(inches) CLASS
3 A
» 6 B
13 Bor1
23 2
CALCULATION:
Minimum TW Conditions: W = Do + La
=3'+18'
=21 ft
3.00
s) 6.47
18.00
THICKNESS
(inches)
9
22
22
27
J.C. Diaz, El
6/2/2008
CONCLUSION:
MINIMUM REQUIRED: NCDOT CLASS `B' RIP RAP
18'L x 2 VW x 22" THK
PROPOSED: NCDOT CLASS `B' RIP RAP
271L x 201W x 22" THK
DISSIPATOR
Permit No. 07-2082
(to be provided by DWQ)
0
M- ^
*A p??f W A T?gdG,
h
_
HCIKHR O r
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 Ill) must be printed, filled out and submitted along with all of the required information.
Is PROJECT INFORMATION
Project name Highway 29 Project
Contact person James W. Caldwell
Phone number [phone]
Date 5/22/2008
Drainage area number To Pond #3
II. DESIGN INFORMATION
Site Characteristics
Drainage area 108,028.80 fe
Impervious area 62,726.40 fe
% impervious 58.06 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 4,222.00 ft3
Volume provided 21,262.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth NIA in
Pre-development 1-yr, 24-hr runoff N/A ft3
Post-development 1-yr, 24-hr runoff N/A ft3
Minimum volume required #VALUE! ft3
Volume provided NIA ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth NIA (See Note 1) in
Rational C, pre-development N/A (unitless)
Rational C, post-development NIA (unitless)
Rainfall intensity: 1-yr, 24-hr storm WA in/hr
Pre-development 1-yr, 24-hr peak flow NIA ft3/sec
Post-development 1-yr, 24-hr peak flow N/A ft3lsec
Pre/Post 1-yr, 24-hr peak flow control #VALUE! ft3lsec
Basin Elevations
Basin bottom elevation 598.00 ft
Sediment cleanout elevation 599.50 ft
Bottom of shelf elevation 603.50 ft
Permanent pool elevation 604.00 ft
SHWT elevation N/A (See Note 2) ft
Top of shelf elevation 604.50 ft
Temporary pool elevation 604.63 ft
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 2
Permit No. 07-2082
(to be provided by DWQ)
I! DESIGN INFORMATION
Volume and Surface Area Calculations
SAIDA ratio 2.32 (unitless)
Surface area at the bottom of shelf 5,211.00 ftz
Volume at the bottom of shelf 16,115.00 ft3
Permanent pool, surface area required 2,502.00 fe
Permanent pool, surface area provided 6,399.00 fe OK
Permanent pool volume 19,518.00 ft3
Average depth for SAIDA tables 3.05 ft OK
Surface area at the top of shelf 7,738.00 fe
Volume at the top of shelf 22,752.00 ft3
Forebay volume 3,704.00 ft3
Forebay % of permanent pool volume 18.98 % OK
Temporary pool, surface area provided 7,876.00 ftz
Drawdown Calculations
Treatment volume drawdown time 3.32 days OK
Treatment volume discharge rate 0.02 ft3ls
Pre-development 1-yr, 24-hr discharge NIA ft3ls OK
Post-development 1-yr, 24-hr discharge NIA ft3ls OK
AAA;H,.. 1 W--*;--
Diameter of orifice 1 in
Design TSS removal 85 %
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 2.2 (See Note 3) :1 OK
Length to width ratio 2.20 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.00 ft OK
Vegetated filter provided? N (See Note 4) (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 8" plug valve (may require pumping for complete drainage)
Notes
1-Peak flow attenuation is not required for compliance with the 401 Water
Quality Certification but the City of Charlotte requires peak flow
attenuation for the 2- and 10-year storm events. Please refer to the
design report for detailed calculations.
2-The pond is situated near the existing stream on site so that the
permanent pool is as close to the SHWT as possible.
3-This is the maximum flowpath to width ratio the pond can achieve because
of site constraints without sacrificing surface area. The proposed
surface area is needed for peak flow attenuation.
4-The existing riparian buffer provides the vegetative filter at the
outlet of the pond. Please refer to the pictures provided.
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
Permit No. 07-2082
(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.
JWC WS-2 1. Plans (1" 50' or larger) of the entire site showing:
SW-3A 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.
JWC SW-3A 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
SW-3B 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.
N/A 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.
JWC SW-3A 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.
JWC see report 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
JWC SW-3A 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
JWC see report 7. The supporting calculations.
JWC attached 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
N/A 9. A copy of the deed restrictions (if required).
JWC see report 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 3 of 3
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 3
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. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.3 Page 1 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 3
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 s ra yin g.
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.3 Page 2 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 3
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.
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 4.50 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 3.75 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Sediment Removal
Bottom
Permanent Pool Elevation 604.00
600.25 Pe manen`?
Volume
\
--------------- --
599.00 -ft Min.
Sediment
Storage
FOREBAY
Pool
------Sediment Removal Elevation 599.50---------- Volum
Bottom Elevation
MAIN POND
1-ft
Storage
Form SW401-Wet Detention Basin O&M-Rev.3 Page 3 of 4
Permit Number: 0 7- 2 0 8 2
(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: Highway 29 Project
BMP drainage area number: Pond #3
Print name: Mr. Dave Ransenberg
Title: Member Manager / President
Address: 11121 Caramel Commons Boulevard Suite 350, Charlotte NC 28266
Phone:
Signatt
Date:( 11196
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 , do hereby certify that
personall appeared before me this ZAO(,
day of ,o7GY> , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
1616810t
V?
to ? •
C) ?.1
ti
ORG C0464"
SEAL
My commission expires c. Z7 Z, e '3
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4

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GRAPHIC SCALE
30 0 15 30 60
1 inch = 30 ft.

FLOW LENGTH PATH
LENGTH = 118' r _ \\
NORMAL POOL = EL 604.0
SA = 6,306 SQ FT
/ I SA REQ. = 2,502 SQ FT
// / j ? III
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II
AVG FLOW WIDTH = 53'
/ / i'/ ; / /IIII I I
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?^ l? lIl /l1/?I I II
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/ WET POND # 3
FLOW LENGTH TO WIDTH RATIO
= 2.2:1
1 l I ? ?/ A
0 HIGHWAY 29 THE JOHN R. McADAMS
COMPANY
INC.
( WG
RE ,
' C
NORTH CAROLINA
` ENGINEERS/PLANNERS/SURVEYORS
,
? RESEARCH TRIANGLE PARK, NC
POND #3 GRADING EXfIIB1T P.O. BOX 14005 ZIP 27709-4005
8 [phone]
#Yr' '

it 11
e
?. ? r.
Highway 29
GWH-06040
Wet Pond #3 Dissipator Calculations
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs : 1.05 Flow depth (ft) = 0.31
slope S in %: 0.50% Outlet velocity (fps) = 2.731
pipe diameter D in in.: 36
Manning number n : 0.013
NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft) 3.00
Outlet velocity (fps) 2.73
Apron length (ft) 18.00
AVG DIAM
(inches)
3
» 6
13
23
CALCULATION:
Minimum TW Conditions: W = Do + La
=3'+18'
=21 ft
STONE THICKNESS
CLASS (inches)
A 9
B 22 «
Bor1 22
2 27
J.C. Diaz, El
6/2/2008
CONCLUSION:
MINIMUM REQUIRED: NCDOT CLASS `B' RIP RAP
18'L x 2VW x 22" THK
PROPOSED: NCDOT CLASS W RIP RAP
27'L x 20'W x 22" THK
DISSIPATOR
Permit No. 07-2082
(to be provided by DWQ)
pt'O? W A r?p?G
f
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 Ill) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Highway 29 Project
Contact person James W. Caldwell
Phone number [phone]
Date 5/22/2008
Drainage area number To Pond #4
II. DESIGN INFORMATION
Site Characteristics
Drainage area 272,685.60 fe
Impervious area 186,436.80 fe
% impervious 68.37 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 12,455.00 ft3
Volume provided 21,183.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth N/A in
Pre-development 1-yr, 24-hr runoff N/A ft3
Post-development 1-yr, 24-hr runoff N/A ff3
Minimum volume required #VALUE! ft3
Volume provided N/A ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth N/A (See Note 1) in
Rational C, pre-development N/A (unitless)
Rational C, post-development N/A (unitless)
Rainfall intensity: 1-yr, 24-hr storm NIA in/hr
Pre-development 1-yr, 24-hr peak flow NIA ft3lsec
Post-development 1-yr, 24-hr peak flow N/A ft3lsec
Pre/Post 1-yr, 24-hr peak flow control #VALUE! ft3/sec
Basin Elevations
Basin bottom elevation 588.00 ft
Sediment cleanout elevation 589.50 ft
Bottom of shelf elevation 593.50 ft
Permanent pool elevation 594.00 ft
SHWT elevation N/A (See Note 2) ft
Top of shelf elevation 594.50 ft
Temporary pool elevation 595.27 ft
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 2
Permit No. 07-2082
(to be provided by DWQ)
II. DESIGN INFORMATION
Volume and Surface Area Calculations
SA/DA ratio 2.80 (unitless)
Surface area at the bottom of shelf 6,543.00 fe
Volume at the bottom of shelf 20,429.00 ft3
Permanent pool, surface area required 7,635.00 fe
Permanent pool, surface area provided 8,146.00 fe OK
Permanent pool volume 24,873.00 ft3
Average depth for SA/DA tables 3.05 ft OK
Surface area at the top of shelf 10,033.00 fie
Volume at the top of shelf 29,057.00 ft3
Forebay volume 4,790.00 ft3
Forebay % of permanent pool volume 19.26 % OK
Temporary pool, surface area provided 11,173.00 f 2
Drawdown Calculations
Treatment volume drawdown time 2.97 days OK
Treatment volume discharge rate 0.07 ft3/s
Pre-development 1-yr, 24-hr discharge N/A ft3/s OK
Post-development 1-yr, 24-hr discharge
A.1.6.i..... 1 is........ ;-- WA ff3/s OK
Diameter of orifice 1.5 in
Design TSS removal 85 %
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 3.00 :1 OK
Length to width ratio 3.00 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.00 ft OK
Vegetated filter provided? N (See Note 3) (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 8" plug valve (may require pumping for complete drainage)
Notes
1-Peak flow attenuation is not required for compliance with the 401 Water
Quality Certification but the City of Charlotte requires peak flow
attenuation for the 2- and 10-year storm events. Please refer to the
design report for detailed calculations.
2-The pond is situated near the existing stream on site so that the
permanent pool is as close to the SHWT as possible.
3-The existing riparian buffer provides the vegetative filter at the
outlet of the pond. Please refer to the pictures provided.
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
Permit No. 07-2082
(to be provided by DWQ)
{II. 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.
JWC WS-2 1. Plans (1" 50' or larger) of the entire site showing:
SW-4A 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.
JWC SW-4A 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
SW-4B 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.
N/A 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.
JWC SW-4A 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.
JWC see report 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
JWC SW-4A 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
JWC see report 7. The supporting calculations.
JWC attached 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
N/A 9. A copy of the deed restrictions (if required).
JWC see report 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 3 of 3
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 4
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. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.3 Page 1 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 4
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.3 Page 2 of 4
Permit Number: 0 7- 2 0 8 2
(to be provided by DWQ)
Drainage Area Number: 4
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.
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 4.50 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 3.75 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
Sediment Removal
Bottom
Permanent Pool Elevation 594.00
590.25 1 Pe manenN
--------------- --Volume
589.00 -ft Min.
Sediment
Storage
FOREBAY
Pool
------Sediment Removal Elevation 599.50---------- Volume
Bottom Elevation
MAIN POND
1-ft
Storage
Form SW401-Wet Detention Basin O&M-Rev.3 Page 3 of 4
Permit Number: 0 7- 2 0 8 2
(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: Highway 29 Project
BMP drainage area number: Pond #4
Print name: Mr. Dave
Title: Member Manager / President
Address: 11121 Caramel Commons Boulevard Suite 350 Charlotte NC 28266
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.
I, a Notary Public for the State of
c County of do hereby certify that
personally appeared before me this Z .41
day-ol 7' and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
74
0TAF?V,
'; U=
-
Vin
fog J, G 0 0%
!!!1!!l?l?j1
SEAL
My commission expires_ f7 ZdIS
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4

-? NORMAL POOL = EL 604.0
'<- \ \ SA = 8,146 SO FT
SA REQ. = 7,635 SO FT
\ ?? \
.? \\ \ \\\ ? \ ? FROM ?? ? - \\
N FLOW LENGTH PATH \ \ \ ' \ \ \\\ '\
LENGTH = 163' \ \_ \
00 \ \ \ \
00
M \ \? \ \ \ \ - \ \
00
N \ \ \ \ \ \
N \\ AVG FLOW WIDTH = 54.5' \ \ \
U) \?< \ \ \
3 \ \\\\ \ \\ \\ \ \
WET POND # 4 \ \ \ \ \ \
° 'S \ FLOW LENGTH TO WIDTH RATIO \
2 ?\ = 3:1 \ \
0
v\? v?
Ca \\ 'N \\ n\ \ \ \\\ \
o \ \ \ ?,\ \? \? \ \\ - _ \ \ \ \
I , GRAPHIC SCALE
E 30 0 15 30 60
0
0 Q 1 inch = 30 ft.

® PROJECT NO.. GWH-06040 HIGHWAY 29 THE
JOHN R.
McADAMS

FILENAME:
GWH06040-WS2.DWG COMPANY,
INC.

d
SCALE:
C
NORTH CAROLINA ENGINEERS/PLANNERS/SURVEYORS
AS NOTED , RESEARCH TRIANGLE PARK, NC
DATE, POND #4 GRADING EXHIBIT P.O. BOX 14005 ZIP 27709-4005
05-19-2008 [phone]

Pond #4 - Natural Vegetated Buffer at Outlet
Pond #4 - Natural Vegetated Buffer at Outlet
Highway 29
G W H-06040
Wet Pond #4 Dissipator Calculations
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs : 30.94 Flow depth (ft) = 1.77
slope S in %: 0.50% Outlet velocity (fps) = 7.116
pipe diameter D in in.: 36
Manning number n : 0.013
NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft)
Outlet velocity (fp
Apron length (ft)
AVG DIAM STONE
(inches) CLASS
3 A
» 6 B
13 Bor1
23 2
CALCULATION:
Minimum TW Conditions: W = Do + La
= 3' + 18'
=21 ft
3.00
s) 7.12
18.00
THICKNESS
(inches)
9
22
22
27
J.C. Diaz, El
6/2/2008
CONCLUSION:
MINIMUM REQUIRED: NCDOT CLASS `B' RIP RAP
18'Lx21'Wx22"THK
PROPOSED: NCDOT CLASS `B' RIP RAP
27'L x 20'W x 22" THK
DISSIPATOR