20091085 Ver 2_More Info Received_20100211

Kimley-Horn
- --andAssociates;,nc. -- -
February 10, 2010
Mr. Joseph Gyamfi
2321 Crabtree Blvd
Raleigh, NC 27604
R- V D-2 S V z--
Subject: Troutman Towne Center - Troutman, NC
Comment Response Letter
Our Ref: 018426001
Dear Mr. Gyamfi:
¦
Suite 100
1919 South Boulevard
Charlotte, North Carolina
28203-4778
G L v 1.9
t" EB 1 ? 20,110
DE,%R. WATER QUALITY
tt&TtA" n AND STom-4%NTER BRANI M
We are writing in response to the engineering review comments for the subject
project. A list of the comments and our responses follows:
1. Please extend the clay liner to the temporary pool elevation or raise the
permanent pool elevation to 868 ft or higher. The clay liner must be
shown in the cross sections of both ponds.
The clay liner has been extended to the temporary pool elevation.
The liner is now shown on the pond cross sections (C27) in addition
to the note on sheet C26.
2. Please submit a notarized Operation and Maintenance Agreement for the
level spreader.
Original document is forthcoming and should arrive at the DWQ
office no later than February 11th, at 5pm.
3. Please ensure that the outlet pipe from wet pond 1 discharges at an angle
(>135° preferred) to the level spreader channel, and not nearly
perpendicular.
The outlet control structure outlets at approximately 125° to the
level spreader. This angle is maxed out due to the proximity of the
existing wetlands.
4. Please correct the contour labeling of the weir between the larger forebay
and the main pond for wet pond 1.
The contour labeling has been corrected.
¦
TEL [phone]
FAX [phone]
Mr. Joseph Gyamfl, February 10, 2010, Page 2
Kimley-Horn
Associates; Inc,
We trust this meets your needs for continued review of this project, but please
feel free to call me at [phone] with any questions or concerns.
Sincerely yours,
KIMLEY-HORN AND ASSOCIATES, INC.
Beverly Rosenbloom, El
Enclosure
(K:\CSE_LDEV\018426 Chivas Retail Partners\000 Troutman Towne Center\Correspondence\L021010.DWQ-CONfNENT-RESPONSE.BRR.doc)
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NCDENR `
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER, FILTER STRIP AND RESTORED RIPARIAN BUFFER SUPPLEMENT
This form must be completely filled out, printed and submitted.
DO NOT FORGET TO ATTACH THE REQUIRED ITEMS CHECKLIST AND ALL REQUIRED ITEMS (NEXT WORKSHEET)!
L PROJECT INFORMATION
Project name Troutman Towne Center
Contact name Beverly Rosenbloom
Phone number 704-319-7699
Date February 10, 2010
Drainage area number DA-1
If,; DESIGN INFORMATION
For Level Spreaders Receiving Flow From a BMP
Type of BMP Wet Detention Pond 1
Drawdown flow from the BMP 0.37 cfs
For Level Spreaders Receiving Flow from the Drainage Area Do not complete this section of the worksheet.
Drainage area fiz Do not complete this section of the worksheet.
Impervious surface area ft2 Do not complete this section of the worksheet.
Percent impervious % Do not complete this section of the worksheet.
Rational C coefficient Do not complete this section of the worksheet.
Peak flow from the 1 in/hr storm cfs Do not complete this section of the worksheet.
Time of concentration min
Rainfall intensity, 10-yr storm in/hr Do not complete this section of the worksheet.
Peak flow from the 10-yr storm cfs Do not complete this section of the worksheet.
Where Does the Level Spreader Discharge?
To a grassed bioretention cell? (Y or N)
To a mulched bioretention cell? (Y or N)
To a wetland? Y (Y or N) Please complete filter strip characterization below.
To a filter strip or riparian buffer? (Y or N)
Other (specify)
Filter Strip or Riparian Buffer Characterization (if applicable)
Width of grass 0.00 ft
Width of dense ground cover 42.00 ft
Width of wooded vegetation 0.00 ft
Total width 42.00 ft
Elevation at downslope base of level lip 864.00 fmsl
Elevation at top of bank of the receiving water 863.00 fmsl
Slope (from level lip to to top of bank) 2.38 % OK
Are any draws present? N (Y or N) OK
Level Spreader Design
Forebay surface area sq ft No forebay is needed.
Feet of level lip needed per cfs 13 ft/cfs
Answer "Y" to one of the following:
Length based on the 1 in/hr storm? N (Y or N)
Length based on the 10-yr storm? Y (Y or N)
Length based on the BMP discharge rate? Y (Y or N)
Design flow 3.22 cfs
Is a bypass device provided? N (Y or N) A bypass device is not needed.
Form SW401-1-evel Spreader, Filter Strip, Restored Riparian Buffer-Rev.5 Parts I. and II. Design Summary, page 1 of 2
Length of the level lip
Are level spreaders in series?
Bypass Channel Design (if applicable)
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Dimensions of the channel (see diagram below):
M
B
W
y
Peak velocity in the channel during the 10-yr storm
Channel lining material
42.00 ft
N (Y or N)
#VALUE! '
(Y or N) Do not complete this section of the worksheet.
(Y or N) Do not complete this section of the worksheet.
Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
ft Do not complete this section of the worksheet.
cfs Do not complete this section of the worksheet.
Do not complete this section of the worksheet.
1 W
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Y
1 B 1
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Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.5 Parts I. and ll. Design Summary, page 2 of 2
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.
Paget Plan
Initials Sheet No.
BRR C14, C26 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),
Forebay (if applicable),
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW), and
Boundaries of drainage easement.
BRR C26 2. Plan details (1" = 30' or larger) for the level spreader showing:
Forebay (if applicable),
High flow bypass system,
One foot topo lines between the level lip and top of stream bank,
Proposed drainage easement, and
Design at ultimate build-out.
BRR C26 3. Section view of the level spreader (1" = 20' or larger) showing:
Underdrain system (if applicable),
Level lip,
Upslope channel, and
Downslope filter fabric.
BRR Attached 4. A date-stamped photograph of the filter strip that clearly shows the type of vegetation that is present.
BRR C06-C10 5. A construction sequence that shows how the level spreader will be protected from sediment until the
entire drainage area is stabilized.
BRR Attached 6. The supporting calculations.
BRR Attached 7. A copy of the signed and notarized operation and maintenance (0&M) agreement.
BRR 8. A copy of the deed restrictions (if required).
Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.5 Part III, page 1 of 1