20210224 Ver 1_NCDWR Response letter_Westpoint_3-28-2022_FINAL_20220328

Environmental Consultants,
8412 Falls of Neuse Road, Suite 104, Raleigh, NC 27615 • Phone: [phone] • Fax: [phone]
sandec.com
March 28, 2022
S&EC Project #13706.W13
NC DWR, 401 & Buffer Permitting Unit
Attn: Paul Wojoski
1617 Mail Service Center
Raleigh, NC 27699-1617
Re: Request for Additional Information
Westpoint
AID #SAW-2006-40196; DWR #20210224
Durham, Durham County, NC
Dear Mr. Wojoski:
The purpose of this letter is to respond to a Request for More Information letter dated March 18,
2022 from the NC Division of Water Resources (NCDWR). The original questions/requests from
the March 18, 2022 letter are below and are followed by responses.
Additional Information Requested:
1. The Division requested a copy of the Stormwater Management Plan (SMP) for this project in
a previous request for additional information dated November 16, 2021. The provided plans,
received December 16, 2021, included calculations for wetlands sizing but no design details
were provided. The following additional information is needed to clarify and complete the
plan [15A NCAC 02H .0502(c); 15A NCAC 02H .0506(b)(1)].
a. The drainage, peak flow, and water quality analysis maps submitted with the
stormwater analysis are illegible. Please submit new maps (as a separate file) that
clearly shows:
All of the requested maps are included in the attached Stormwater Impact
Analysis (SIA) - D1900225 - Eno Village - SIA -1801 CDs 2022-03-07.pdf. The
provided SIA in this resubmittal is based on the current CD's. Note Westpoint at
Eno name has changed to Eno Village. See pages 49-51 and 261-262 in the pdf of
the attached SIA. Note that these are 24x36 plan sheets, so they may not print
legibly on smaller size paper. If the Division would like 24x36 hard copies of the
relevant plan sheets, please provide the Division's preferred address for delivery.
Identification and boundary for each of the drainage basins (different color line for
each basin is recommended);
Separate pdf files are included (01_Pre-Development Drainage Area Map,
02 Post -Development Drainage Area Map and 02_Post-Development
Drainage Area Map -Hatch) that show the pre- and post -development
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drainage basins to the points of analysis. Basins 1, 2, and 5 drain to the
streams on the east and west sides of the site.
Identification and location of each analysis point and outfall:
The pdf s noted in the response above show the analysis points. As noted,
Basins 1, 2, and 5 drain to the streams on the east and west sides of the
site. In addition, the included pdf, 03_Grading Plans — SCM Locations,
includes the locations of the inlets, outlets, and discharge locations from
each of the proposed stormwater wetlands.
iii. Identification and location of each proposed stormwater wetland including their
inlet and outlet locations;
The included pdf, 03_Grading Plans — SCM Locations, includes the
locations of the inlets, outlets, and discharge locations from each of the
proposed stormwater wetlands.
iv. Essential collection system routing stormwater in the drainage area to each
SCM;
The proposed storm drain piping system is shown on the pdf, 03—Grading
Plans — SCM Locations. In addition, the (HGL) storm drain calculations
(131900225 - Eno Village — HGL.pdf) and construction drawings sheets C3.1
— C3.62 from the Eno Village - Construction Drawings 2022-03-10 set are
included for reference.
v. Relevant stream(s) and water features;
The streams, wetlands, and buffers are shown on all of the plan sheets.
The included pdf, EXISTING CONDITIONS Westpoint pdf was included
within the original application submittal with all streams, wetlands and
riparian buffers identified. Note that the City of Durham requires 100 ft
buffers on the streams, these additional buffers not required by the
NCDWR are not shown on this exhibit.
V- Any vegetative conveyances and energy dissipaters (if provided);
The conveyance system and dissipaters are shown on all of the plan
sheets. The included pdf, 05-07_Streams-Dissipaters-Easement.pdf.
vii. Easement and maintenance access to each of the stormwater wetlands. A
minimum 10-foot wide access around the SCM is required.
The SCM maintenance and access easements are shown on all of the plan
sheets. The included pdf, 05-07_Streams-Dissipaters-Easement.pdf. These
are shown in purple. These easements are outside of the 50 ft stream
buffers.
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b. Provide a copy of the O&M Plan for the stormwater wetlands including estimated
annual maintenance cost (ex. Trash/debris removal, inspection, plants trimming and
maintenance, etc.).
Drafts of the O&M's are included with the additional information request. These
do not include estimated annual maintenance costs as the City does not require
this information to be included. With that said, the annualized maintenance costs
for a large stormwater wetland based on NCSU's Annualized Maintenance Costs
spreadsheet is $4,706.
2. The Division has received comments indicating that site development work, such as
clear cutting and vegetation removal on site may have been initiated. Please indicate if
any impact to regulated riparian buffers has occurred. [15A NCAC 02B .0714(3)].
The City of Durham has recently conducted clearing on a portion of the site as
part of its sewer replacement project (Eno River Outfall Upgrade Phase II). A
portion of this plan set showing the City's project area in which clearing may have
occurred, as well as copies of the easement request documents from the City to
the property owner (Letter of Intent -Offer -Point Ridge Park 2 & Sheet TC3_VE104-
30790012_Temp Constr Access_3), are included with this response. Sheet
C4_VE109-30790012—Outfall Sta 40+50 to 44+50.pdf is associated with the City's
Eno River Outfall project and not associated with the Eno Village future project.
Prior to the 401 application, there was also some limited clearing on the site in
order to perform geotechnical investigation, please see Geotech Clearing exhibits.
After this work was performed, Durham County issued a Notice of Violation (NOV)
in August 2021 as the land disturbance exceeded the disturbance threshold for a
permit. Upon receiving this notice, the contractor immediately stabilized the
disturbed areas and addressed the NOV as evidenced by a Notice of Site
Compliance (NoSC) letter dated September 15,2021. Both the NOV and the NoSC
letter are enclosed with this response.
We anticipate that this will provide answers to the NCDWR's questions/concerns. If additional
information is needed, please do not hesitate to email me at dsNrley(t�sandec.com
Sincerely, ^
L�
Deborah E. Shirley
Project Manager -Regulatory Specialist
CC:
Jon Holtvedt-Terramor Homes (email)
April Norton-USACE (email)
Attachments:
1) D190025 — Eno Village — SIA — 1801 CDs 2022-03-07
2) 01_Pre-Development Drainage Area Map
Page 3 of 4

3) 02_Post-Development Drainage Area Map
4) 02_Post-Development Drainage Area Map -Hatch
5) 03_Grading Plans — SCM Locations
6) D190025 — Eno Village — HGL
7) DWR Stormwater Response Sheets C3.1 — C3.62
8) EXISTING CONDITIONS Wespoint
9) 05-07_Strearns-Dissipaters-Easement
10) Q&M Manual — Stormwater Wetland — WETLAND 1
11) O&M Manual — Stormwater Wetland — WETLAND 2
12) O&M Manual — Stormwater Wetland — WETLAND 3
13) O&M Manual -- Stormwater Wetland — WETLAND 4
14) Sheet C4—VE109-30790012_Outfall Sta 40+50 to 44+50
15) Letter of Intent -Offer -Point Ridge Park 2
16) Sheet TC3—VE104-30790012_Temp Construction Access_3
17) Pages from 2020.10.27 Eno Phase II IFC Plan Set (signed)
18) Geotech Clearing
19) Notice of Violation
20) Notice of Site Compliance
Page 4 of 4