20061085 Ver 2_More Info Letter_20061128

~O~ W A TFRQ Michael F. Easley, Governor
`t~ (~ William G. Ross Jr., Secretary
Vj rte.. North Carolina Department of Environment and Natural Resources
~ ~ `
~ ,~. Alan W. Klimek, P.E. Director
Division of Water Quality
November 28, 2006
DWQ EXP No. 06-1085
Union County
CERTIFIED MAIL: RETURN RECEIPT REQUESTED
Mr. Donald S. Hughes
Union County Public Schools
116 North Main Street
Monroe, NC 28112
Subject Property: Elementary School G
REQUEST FOR MORE INFORMATION-EXPRESS REVIEW PROGRAM
Dear Mr. Hughes:
On November 16 and 28, 2006, the Division of Water Quality (DWQ) received additional information in
response to our November 7, 2006 request. This is the final request for more information letter you will
receive regarding this project. This re-submittal is still problematic as there are stormwater design-related
issues. This is DWQ's third request for additional information and the project has exceeded satisfying all
requirements for approval within the 30-day Express Review timeframe. If the response to this request
for information is inadequate, you will be required to resubmit your PCN application for stream and
wetland impacts through the regular 401 review process. Please note that your project will be reviewed
for the time being under Express Review, but without the Express Review timeframe.
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:
Stormwater Management Plan:
a. Operation and Maintenance Agreement: DWQ has not received a signed and notarized
operation and maintenance agreement for the bioretention cells. You are required to provide
one (1) original and two (2) copies of this Agreement.
b. Bio-retention Planting Plan: DWQ requires that the plant material be at least 2.5" dbh for trees.
Please explain why your plan specifies the use of smaller material.
c. Drainage Area 1/Bioretention:
i. The required surface area is significantly larger than the permanent pool surface area
you have proposed. Please redesign the bioretention cell for this drainage area in
accordance with DWQ's stormwater BMP design guidance.
ii. DWQ generally recommends a ponding depth of 0.5 feet. Please explain your
temporary pool elevation.
d. Drainage Area 3/Wet Pond:
i. Please explain the volumes for the permanent and temporary pool. You have reduced
the forebay volume to 1597.22; please explain why the forebay volume has been
reduced to 6.1 %. -
ii. Please explain the SA/DA ratio used. The SA/DA ratio does not appear to be based on
the five-foot permanent pool depth.
401 Oversight /Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone; 919-733-17861 FAX[phone]ntemet:http:!/h2o.enr.state.nc.us/ncwetlands
Nose Carolina
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An Equal OpportunitylAffirmative Action Employer - 50% Recycled110% Post Consumer Paper

Elementary School G, Union County
Page 2 of 2
November 28, 2006
iii. DWQ has calculated a 5.2-day drawdown for the wet pond. Please redesign. to shorten
this time.
e. Drainage Area 4Bioretention:
i. DWQ generally recommends a ponding depth of 0.5 feet. Please explain your
temporary pool elevation.
ii. Please explain why the permanent pool surface area is significantly smaller than design
criteria would dictate for the drainage area impervious area.
Please respond within five (5) days of the date of this letter by sending one (1) copy to the attention of:
Cynthia Van Der Wiele, NCDWQ Wetlands Unit/Express Review Program, 2321 Crabtree Blvd., Suite
250, Raleigh, NC 27604 and two (2) sets of this information to the attention of: Barry Love, DWQ
Mooresville Regional Office.
This letter only addresses the application review and does not authorize any impacts to wetlands or
waters. Please be aware that any impacts requested within your application are not authorized (at
this time) by the DWQ. Please contact Cynthia Van Der Wiele at [phone] if you have any
questions regarding this matter.
Sincerely, )
i ~ /
\~~~~~_~
Cyndi Karoly,
401 OversightBxpress Review Permitting Unit
CBIC/cvdw
cc: Barry Love, DWQ Mooresville Regional Office
USACE, Asheville Field Office
File Copy
Central Files
Eddie MacEldowney, Davis-Martin-Powell and Assoc., 6415 Old Plank Road, High Point, NC
27265
Filename: 061085EIementaryschoolG(U nion)EXP+hold3