20071431 Ver 2_More Info Letter_20080410

~pF ~AT~9P Michael F. Easley, Governor
.~~ G William G. Ross Jr., Secretary
~~-- North Carolina Department of Environment and Natural Resources
~ ~
(,'~ ~ Coleen H. Sullins, Director
Division of Water Quality
April 10, 2008
DWQ EXP No. 07-1431v2
Wake County
CERTIFIED MAIL: RETURN RECEIPT REQUESTED
Wake County Public Schools
Attn: Mr. Jeff Young
Facilities Planning & Construction Management
1551 Rock Quarry Road
Raleigh, NC 27610
Project Name: E-31 Elementary
REQUEST FOR MORE INFORMATION
Dear Mr. Young:
On Apri19, 2008, the Express Review Program of the Division of Water Quality (DWQ) received your
application for the above referenced project. The DWQ has determined that your application will require
additional information. Please provide the following information so that we may continue to review
your project and prevent denial of your application as required by 15A NCAC 2H .0506:
Additional Information Requested
1. Diffuse Flow:
a. Please include the existing and proposed contours and their elevations on plan sheets C 1.2.
b. Please provide detail calculations of the peak flow rate from the 10-yr storm routed through
the bioretention basin. In effect, please show how 5.7cfs was determined. .
c. Please provide a cross section detail of the outlet structure showing all inlet and outlet pipes
and elevations.
d. Level spreader detail:
i. Please show the plan view and cross sections of the level spreader system on the
plans.
ii. Include a completed level spreader supplement form along with all required items in
the checklist, and a signed and notarized inspection and maintenance agreement
form.
iii. If the location of.the level spreader is such that all flows exiting the bioretention go to
the level spreader prior to entering the outlet channel, then either bypass higher flows
from the BMP around the level spreader, or design the level spreader to handle the
10-yr storm discharge rate from the BMP (which may not be practicable in this case),
or replace the level spreader with a plunge pool/scour hole of appropriate size, depth
and slope to provide the low flows to the channel.
2. New Storm Drainage Rip Rap
a. As discussed in the pre-application meeting, filling in a buffered stream is prohibited (see sheet
C 1.2). This action would require a major variance from the Environmental Management
Committee.
401 Oversight I Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] FAX [phone] Internet: htto:!/h2o.enr.state.nc.us/ncwetlands
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E-31 Elementary School
Page 2 of 2
April 10, 2008
b. Additionally any "allowable" riparian buffer impact (such as to the beginning of the
intermittent stream channel "A 1 ") for stormwater BMP outflow must be enumerated on the
PCN form.
3. Riparian Buffer Impacts
a. From your impact maps, Zone 1 impacts appear to be 5,400 ft2 and Zone 2 impacts appear to be
4,700 ftZ. It appears that Figure #6 buffer impacts have not been enumerated on the PCN form.
If impacts are being avoided, they should not be listed on the impact maps. Please correct this
error and/or explain the discrepancy.
4. PCN Addendum
a. Please include a copy of the completed PCN addendum (it is a checklist) and provide all
information requested therein.
Please respond within five (5) days of the date of this letter by sending two (2) copies of the above
information in writing. The Express Review Program is a process that requires all parties to participate in a
timely manner.
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 contact Joseph Gyamfi or Lia Myott at 919-733-1786 if you have any questions regarding or
would like to set up a meeting to discuss this matter.
CBK/lem/jg
Sincerel ,
ndi Karoly, Supervisor
O1 Oversight/Express Review Permitting Unit
cc: Jamie Shern, USACE Raleigh Regulatory Field Office
Lauren Witherspoon, DWQ Raleigh Regional Office
File Copy
Central Files
Jason Volker, S&ME Inc., 3201 Spring Forest Road, Raleigh, NC 27616