20061804 Ver 12_More Info Requested_20161017 (2)

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Mr. Jeff Carter
Stocks Engineering, PA
PO Box 1108
Nashville, North Carolina J2.
PA I" MCC RORY
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Johnston County
Subject: REQUEST FOR ADDITIONAL INFORMATION
Stormwater Management Plan for Woodlands @ Flowers Plantation
Dear Mr. Carter:
On September 8, 2016, the Division of Water Resources (Division) received a proposed stormwater
management plan (SMP) for the subject project. A review of the SMP has determined that the
plan is incomplete and cannot be approved at this time. Please address the following items:
Provide supporting calculations detailing overall project BUA and % impervious for each
SCM and include a summary of rooftop, driveway, roadway areas to support the project
built upon area.
2. The required item checklist was not provided for the bioretention cell supplement form —
30"n-10 =som
3. According to the site plan on sheet CE -01 depicting final BMP drainage areas approximately
nine (9) full lots and 57 half lots from the perimeter of the development bypass the two
proposed BMPs. Note that high density projects must capture and treat runoff from all
new imperviousness which may necessitate construction additional BMPs. Another option
would be increase the water quality volume for each proposed BMP to treat an equivalent
amount of impervious area that drains away. Please revise the SMP design and associated
documents as necessary.
4. Provide outlet protection sizing calculations for bioretention and wet detention pond
outfalls. Provide documentation that 10 -year storm discharges are released at a non-
erosive velocity to surface waters and will not result in erosion of the 50 foot Neuse
riparian buffer.
Stite ot'North Carolina I Environmental Quality I Water Resources 1401 & Buffer Pernlining
1617 Mail service Center I Raleigh, North Carolina 27699-1 61 7
919707 6300

Pursuant to Title ISA NCAC 02H .0502(e) the applicant shall furnish all of the above requested
information for the proper consideration of the application, if all of the requested information is
not received in writing at the address below within 30 calendar day of receipt of this letter, the
Division will be unable to process the application and it will be returned. The return of this project
will necessitate reapplication to the Division for approval, including a complete application
package and the appropriate fee.
questions or concerns.
cc: DWR 401 & Buffer Permitting Branch File
DWR RRO File
Sincerely,
Karen Higgins, Supervisor
401 & Buffer Permitting Branch
Filename: Woodlands -Flowers SME