20090501 Ver 2_More Info Letter_20131021

A
w&V
North Carolina Department of Environment and Natural Resources
Pat McCrory
Governor
Mr. Scott Twiddy
Division of Water Resources
Water Quality Programs
Thomas A. Reeder
Director
October 21, 2013
Carolina Development Solutions, LLC
1932 Clark Elliot Street
Fort Mill, SC
Subject Property: Chestnut Place, Phase II
Terrible Creek [030403, 27- 43- 15- 8 -(2), C, NSW]
REQUEST FOR MORE INFORMATION: STORMWATER MANAGEMENT PLAN
Dear Mr. Twiddy:
John E. Skvarla, III
Secretary
DWR Project # 09- 05010
Union County
On June 13, 2013, the Division of Water Resources (DWR) issued a 401 Water Quality Certification to
place fill within or otherwise impact the following:
Type of Impact
Amount Approved
(temporary impacts)
Amount Approved
404 /Wetlands
—
0.12 acre
Stream — permanent
75 linear feet
203 linear feet
In order to meet Condition 8 (stormwater management) of the Water Quality Certification and Buffer
Authorization for this project, a stormwater management plan, dated August 28, 2013, was received on
August 30, 2013. The Division has determined that your stormwater management plan was incomplete
as discussed below.
Additional Information Requested:
Stormwater may not be directed to a natural wetland for treatment unless it can be
demonstrated:
a. That the stormwater conveyances discharging to the wetland will be at a non - erosive
flow of two feet per second or less during the ten -year, twenty -four hour storm, AND
b. That the stormwater can be retained for a period of two to five days prior to discharge
and that this will not result in harm to the native wetland plants.
1617 Mail Service Center, Raleigh, North Carolina 27699 -1617
Phone: [phone] FAX: 919 - 733558
Internet: www.ncwaterguality.org
An Equal Opportunity 1 Affirmative Action Employer

Mr. Scott Twiddy
October 21, 2013
Page 2 of 2
2. If you do decide to treat stormwater in the natural wetland, then you must provide a complete
Stormwater Wetland Supplement Form and Required Items Checklist with all required items.
The supplement form is available at: http: / /oortal.ncdenr.org /web /wa /ws /su /bmp -ch9. Some
of the items that were omitted in the submittal include plans of the site at 1" = 50' or larger, the
boundaries of the drainage easement, details of the outlet structure, a section view,
calculations, and an operation and maintenance agreement. Please see the required items
checklist for a complete list.
3. The proposed infiltration trenches do not appear to be designed correctly. Infiltration trenches
must be level in order to retain and infiltrate stormwater. Also, the submittal does not include
calculations to show that the infiltration trenches can infiltrate the design storm from their
drainage areas.
4. For each proposed infiltration trench, provide a complete Infiltration Trench Supplement Form
and Required Items Checklist with all required items. The supplement form is available at:
http: / /Portal.ncdenr.org /web /wq /ws /su /bmp -ch16. Some of the items that were omitted in
the submittal include plans of the site at 1" = 50' or larger, the boundaries of the drainage
easement, details of the flow splitting structure, a section view, a soils report documenting the
soil infiltration rates, calculations, and an operation and maintenance agreement. Please see
the required items checklist for a complete list.
5. It appears that there is a ditch behind lots 69 -73 that conveys untreated stormwater to an
adjacent lot. This stormwater must be collected and treated in a properly designed stormwater
BMP.
Thank you for your attention to this matter. If you have any questions or wish to discuss these matters
further, please do not hesitate to contact Annette Lucas at (919) 807 -6381.
Sincerely,
1
Karen A. Higgins, Supe r
401 & Buffer Permitting nit
KAH/aml
cc: DWR, Mooresville Regional Office
USACE Asheville Regulatory Field Office
DLR Mooresville Regional Office
Mr. Greg Antemann, CWS, 550 East Westinghouse Boulevard, Charlotte, NC 28273
File Copy
Filename: 090501v2ChestnutPlaceSD (Union)SW_Hold.docx