20100251 Ver 1_More Info Letter_20100503

NCDEE R
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
May 3, 2010
CERTIFIED MAIL: RETURN RECEIPT REQUESTED
Mr. Rodney Tart
Harnett County Department of Public Utilities
P.O. Box 119
Lillington, NC 27546
Subject Property: Brightwater Medical Complex
Ut to Neills Creek [030607, 18-16-(0.7), WSIV]
REQUEST FOR MORE INFORMATION
Dear Mr. Tart:
DWQ Project # 10-0251
Harnett County
On March 31, 2010, the Division of Water Quality (DWQ) received your application dated March 30,
2010, to fill or otherwise impact 0.35 acres of 404/wetland and 219 linear feet of perennial stream, to
construct the proposed mixed-use development at the site. On April 9, 2010, the DWQ received
additional information from you, however, the DWQ has determined that your application remains
incomplete and/or provided inaccurate information as discussed below. The DWQ will require additional
information in order to process your application to impact protected wetlands and/or streams on the
subject property. Therefore, unless we receive five copies of the additional information requested below,
we will place this project on hold as incomplete until we receive this additional information. 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:
Brightwater Biotechnologv_and Medical Center:
1. Please clarify which parts of the proposed development are Phase I and Phase II on a full-sized
plan sheet that shows surface waters, topographic lines and all anticipated impervious surfaces.
2. You must provide the Required items Checklist associated with each of the Wet Detention Basin
Supplement Forms and all required items listed therein at the correct scales. The checklist
includes a signed and notarized Operation and Maintenance Agreement for the wet detention
ponds as well as many other items. If all required items are not included in the next
submittal, your application will be returned.
3. Please provide a table of elevations, areas, incremental volumes and accumulated volumes for the
ponds and forebays. This must include rows for key elevations (bottom, sediment cleanout,
permanent pool, temporary pool, etc.).
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone]
Internet: hdp://h2o.enr.state.nc.us/ncwetlands/
NorthCarohna
A I
Witrally
An Equal Opportunity 1 Affirmative Action Employer
Harnett County Department of Public Utilities
Page 2 of 4
May 3, 2010
4. Please show the following items on the pond profiles:
a. The forebay invert, ponds invert and sediment clean-out elevations.
b. The correct side slopes: 10:1 for the vegetated shelf and 3:1 elsewhere.
c. The permanent and temporary pond elevations as well as any other relevant storage
elevations.
d. The size, length and slope of the outlet barrel.
5. The average depths provided are less than the required minimum of 3 feet. This depth cannot
include the 1' of sediment storage. Please revise the ponds to provide the minimum depth or
more. Please correct the errors in the calculation of average depth in your resubmittal.
6. The forebay volumes must comprise 10 percent of the total volume of the BMP. None of the four
ponds have an appropriate forebay volume.
7. Planting plans for the ponds must be provided on the plans as per 10.3.7 of the BMP manual.
8. Please provide the drawdown calculations for each pond.
9. Please provide a soils test based on in-field borings conducted in the footprint of the proposed wet
detention ponds to document the SHWT elevation. Liners may be required if it is well below the
permanent pool elevations. See also 10.3.2 of the BUT manual.
10. Please show details of all the pond outlets and associated energy dissipation devices.
11. Per the BMP Manual, the emergency spillway must be hardened with concrete, rip rap or other
appropriate material.
12. Please be sure that any changes are consistently reflected on all documents (plans, calculations,
supplement forms, etc.)
13. For the Phase II portion of the site, you must provide a conceptual stormwater management plan
that includes the following:
a. A depiction of the drainage areas on the site.
b. An estimation of the percentage imperviousness associated with each of the drainage
areas.
c. A calculation of the water quality volume associated with each drainage area.
d. A depiction of the proposed BMP (state the type of BMP you plan to use) on the site plan
that is correctly sized based on the water quality volume.
Harnett Health Hospitals:
1. Please address the following issues with Wet Detention Basin #2:
Harnett County Department of Public Utilities
Page 3 of 4
May 3, 2010
a. The pond appears to be short circuiting. Please shift the outlet location to lengthen the
flow path length to width ratio. A ratio of at least 3:1 (L: W) is recommended.
b. The 18" pipe discharging into the pond needs to enter the pond via a forebay.
c. Sizing of the pond must take into account the build-out of the offsite drainage area to the
north. Another option would be to bypass that area around the pond, and treat it
separately if it is ever developed.
2. Please address the following issues with Wet Detention Basins # 1 and #2:
a. The double 6-inch diameter orifices appear to draw down in less than 2 days. Also,
please provide drawdown calculations that show that the minimum required treatment
volume draws down in 2 to 5 days.
b. Please provide calculations that show how the treatment volume was calculated using the
Simple Method.
c. The stage storage output provided does not provide all the information needed. Please
provide a table of elevations, areas, incremental volumes and accumulated volumes for
the overall pond and forebay so that we can verify volumes, areas, and elevations
provided on the plans and supplement forms. This must include rows for key elevations
(bottom, sediment cleanout, permanent pool, temporary pool, etc.).
d. On page 3 of the O&M Agreements, the elevations for when sediment is to be removed
are incorrect.
e. The average depths provided are less than the required minimum of 3 feet. This depth
cannot include the F of sediment storage. Please revise the ponds to provide the
minimum depth or more.
f. Please provide the SHWT elevations. A liner may be required if it is well below the
permanent pool elevation. See also 10.3.2 of the BMP Manual.
g. Planting plans for the ponds must be provided on the plans as per 10.3.7 of the BMP
Manual.
h. Please provide outlet details on the plans showing orifices, weirs, trash rack, etc.
i. We recommend adding an emergency spillway in the event the outlet structure gets
clogged. That way the flow is released in a controlled manner.
j. The outlet structures should be moved closer to the bank of the ponds to allow for easier
inspection and maintenance of the outlets.
3. Please be sure that any changes are consistently reflected on all documents (plans, calcs,
supplement forms, O&M forms, etc.)
Please submit this information or otherwise address this request within 30 calendar days of the date of this
letter. 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.
Harnett County Department of Public Utilities
Page 4 of 4
May 3, 2010
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 Mr. Ian McMillan or Ms. Amy Chapman at 919-733-1786 if you have
any questions regarding or would like to set up a meeting to discuss thi matter.
Sin ly,
Ian McMillan, Acting Supervisor
401 Oversight/Express Review Permitting Unit
UM
cc: Crystal Amschler, U.S. Army Corps of Engineers - Wilmington Regulatory Field Office
Chad Turlington, DWQ Fayetteville Regional Office
File Copy
Troy Beasley, Withers & Ravenel, 1410 Commonwealth Drive, Suite 101, Wilmington, NC 28403
Hunter Freeman, Withers & Ravenel, 111 Mackenan Drive, Cary, NC 27511
Warren Sugg, Mulkey Engineers & Consultants, P.O. Box 33127, Raleigh, NC 27636
Filename: 100251BrightwaterMedica[Complex(Harnett)On_Hold2

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1. Article Addressed to:
RODNEY TART 5/4/10
HARNETT COO EPT OF PUBLIC UTILITIES
PO BOX9
LILLINGTON NC 27546
DWQ 10-0251 HARNETT CO
Agent
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X / , 2 Addressee
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