20110749 Ver 1_More Info Letter_20110919

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NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
September 19, 2011
DWQ Project # 11-0749
Johnston County
CERTIFIED MAIL: 7010 1870 0001 3428 0716
RETURN RECEIPT REQUESTED
Jeremy Dowd Medlin
M/I Homes of Raleigh, LLC
1511 Sunday Drive, Suite 100
Raleigh, NC 27607
Subject Property: Flowers Plantation - Dogwood
UT to Mill Creek (030402, 27-39, WS-IV; NSW)
REQUEST FOR MORE INFORMATION
Dear Mr. Medlin:
On August 15, 2011, the Division of Water Quality (DWQ) received your application dated August 11, 2011 and
received additional information on August 22, 2011 to fill or otherwise impact 2,031 square feet of Zone 1 Neuse
River basin protected riparian buffer (permanent impacts) and 12,047 square feet of Zone 2 Neuse basin protected
riparian buffer (permanent impacts) associated with a residential development. The DWQ has determined that your
application was incomplete and/or provided inaccurate information as discussed below. The DWQ will require
additional information in order to process your application to impact protected buffers on the subject property. This
project is on hold and incomplete until we receive the additional information requested below. If we do not receive
the requested information, your project will be formally returned as incomplete. Please provide the following
information so that we may continue to review your project.
Additional Information Requested:
1. Please provide an agent authorization letter for the application signature.
2. Pertaining to Page 7 of 11, D.1. Avoidance and Minimization
a. Where will the retaining wall be located? If it will be in the buffer please indicate on the IMP 1.
b. You describe level spreaders providing diffuse flow but please explain how diffuse flow will be
achieved at the outlets of the two sediment basins (C-8). If this is not possible then these basins
will need to be reconfigered and/or relocated to avoid concentrated flow at these two locations.
NonehCarolina
Naturally
North Carolina Division of Water Quality Raleigh Regional Office Surface Water Protection Phone [phone] Customer Service
Internet: www.ncwaterquality.org 1628 Mail Service Center Raleigh, NC 27699-1628 FAX [phone]
An Equal Opportunity/Affirmative Action Employer-50% Recycled/10% Post Consumer Paper
Page 2
Pertaining to IMP 1:
a. Clearly show Zone 1 and Zone 2 on the impact map (IMP 1).
b. Zone 2 Impact 8,200 square feet appears to be shaded incorrectly. Please revise map and
resubmit.
c. Why is Impact 5 - 1,137 sqaure feet of Zone 2 needed?
4. The Limits of Disturbance on Plan Sheet C-8 does not match the buffer line in some places on IMP 1.
Please revise the plan and impact map to accurately depict the Limits of Disturbance and Impacts. If
additional buffer impacts are warranted then please also revise appropriate informaiton in the PCN
application.
5. Pertaining to Sheet D-2:
a. Please allocate more space for the blind swale, level lip and #57 stone. The plan view shows
about six feet in width for these BMP elements; however, your detail shows that over 11 feet of
width is needed.
b. Please provide watering specifications to establish the sod in the vegetated filter strip.
c. Please provide dimensions for the level lip and footer in section view.
d. The construction sequence discusses installing a forebay; however, it appears that the blind swale
is being used as the forebay in this design.
e. If it is your intent to use the blind swale as the forebay, then the depth will need to be increased to
18 inches.
f. Please provide proposed topographic contours for the blind swale and provide proposed grading
directions that will prevent stormwater from short-circuiting around each end of the level
spreader.
g. Please provide plans for each of the three proposed flow splitting devices.
h. Please provide details for the dissipater pads located downslope of the bypass channel outlets.
6. Pertaining to Level Spreader 1:
a. The Supplement Form shows that the drainage area for this level spreader is 0.41 acre. However,
the Runoff Map (Sheet C-1) that you provided shows that there are portions of a number of lots
that also drain to this device. Please correct the drainage area size and adjust the size of the level
spreader accordingly.
b. Sheet C-1 shows that the drainage from the road and the lots is initially conveyed in ditches that
flatten out prior to hitting the level spreader. The DWQ is concerned that this approach may
result in erosion through the flattened area and recommends retaining the ditches until the water
is dispersed into the blind swale.
c. Please accurately calculate the surface area of the forebay and report this in the Supplement
Form.
7. Pertaining to Level Spreaders 2 and 4:
a. Please relocate the level spreader and vegetated filter strip such that is it completely outside of the
protected riparian buffer. See Figure 8-5 of the BMP Manual, available at:
http://portal.ncdenr.org/c/document library/get file?uuid=5d698fDO-caaa-4f64-aclf-
d 1561 b4fd53d&groupId=38364.
b. Please accurately calculate the surface area of the forebay and report this in the Supplement
Form.
Page 3
8. It appears that there is a ditch located between the drainage areas of level spreaders 2 and 3 that
discharges directly to the protected riparian buffer. Please either re-grade this area to avoid concentrated
flow or provide an appropriately designed LS-VFS to diffuse the flow from the ditch.
Please submit three copies of this information within 30 calendar days of the date of this letter. Please send
additional information to DWQ Central Office, Attn: Karen Higgins, 1650 Mail Service Center, Raleigh,
NC 27699-1650 and copy Lauren Witherspoon ([e-mail]). If we do not receive this
requested information within 30 calendar days of the date of this letter, your project will be withdrawn and you
will need to reapply with a new application and a new fee. If you need additional time to compile the information
requested above, please email Lauren Witherspoon ([e-mail]) requesting an extension
and indicate a new date for submittal.
This letter only addresses the application review and does not authorize any impacts to wetlands, waters or
protected buffers. Please be aware that any impacts requested within your application are not authorized (at this
time) by the DWQ. Please call Lauren Witherspoon at 919-791-4251 if you have any questions regarding this
letter or would like to set up a meeting to discuss this matter.
?
Sincere
Danny S}ith
Raleigh egional Office Supervisor
Surface Water Protection Section
cc: DWQ Raleigh Regional Office File Copy
WeBSCaPe -1650 Mail Service Center
Robert Turnbull - Environmental Services Inc., 524 S. New Hope Road, Raleigh, NC 27610
Doug Radford - JPM South Development, 9380 Falls of Neuse Road, Suite 203, Raleigh, NC 27615
Filename: 11-0749-Flowers Plantation - Dogwood_NBR_On-Hold