20230942_Sugar Creek Greenway_Mecklenburg Co_ additional info

Baker, Caroline D
From: Jennifer Burdette <[e-mail]>
Sent: Thursday, August 10, 2023 11:48 AM
To: Conchilla, Ryan
Cc: Kaylie Yankura
Subject: [External] RE: 20230942_Sugar Creek Greenway_Mecklenburg Co.
Attachments: image005.wmz; Ditch Calculations.pdf, Trailhead BUA Exhibit.pdf
CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the Report Message
button located on your Outlook menu bar on the Home tab.
Rya n,
Thank you for your and Susan's review. Please see the responses below and attachments pertaining to your request for
additional information on July 31, 2023, for the Sugar Creek Greenway project located in Charlotte, Mecklenburg
County. Please let me and Kaylie know if you have any follow-up questions.
Thanks,
Jennifer
Avoidance and Minimization
1.) "No temporary impacts are proposed for two separate culvert installations, please discuss."
The two streams referenced are classified as intermittent. Culvert installation will occur during periods of no flow to
ensure that the flowing stream does not come in contact with disturbed areas per Water Quality General Certification
4246, II. General Condition 8 (15A NCAC 02H .0507(c), 15A NCAC 02B .0200). Culvert installation will be conducted from
high ground. Approved erosion and sedimentation control measures and best management practices will be utilized to
prevent in -stream sedimentation and impacts to downstream water quality.
2.) "On page 26, the project begins at Mounting Rock Road and a jurisdictional stream is located to the west in close
proximity. What avoidance measures are proposed in this area to minimize impacts to the downgradient stream feature
during construction?"
A Sediment and Erosion Control Plan for the project will be submitted and approved by Mecklenburg County Land
Development prior to any construction on the site. Likewise, the project will comply with a supplementary NPDES
Construction Stormwater Permit (NCG010000). Examples of erosion control measures associated with this area may
include the use of silt fence, temporary and permanent seed application, erosion control matting, diversion features,
etc.
3.) "Page 33, Stream Impact 9 and 10 — culvert and permanent rip -rap fill placement along the stream bank."
The culvert and riprap dissipator pad associated with proposed Stream Impact 9 and 10 have been designed to maintain
the natural dimension, pattern, and profile of the stream. Additionally, the proposed riprap dissipator pad provides
channel and bank stability in a section of stream that is currently incised and eroding.
4.) "Page 39 — Stream Impact S12 — permanent rip -rap apron at 37 ton"
The proposed Stream Impact S12 is associated with a new stormwater conveyance ditch and addresses concentrated
stormwater flow from an existing outlet pipe connected to a stormwater inlet located on W. Tvyola Road. The dissipator
pad was also designed to accommodate the velocity of sheet flow from an adjacent Duke Energy access road and from
W. Tvyola Rd, located upslope from the proposed greenway. The proposed dissipator pad and culvert are predominately
located within an upland area and provide a stabilized conveyance to Sugar Creek to prevent erosion and stream
degradation. Overall, the design of the dissipator pad aims to maximize the opportunity to slow down stormwater
velocity within a relatively short distance. The installation will include the use of geotextile fabric and clean riprap. The

project will adhere to an approved Sediment and Erosion Control plan and the use of best management practices to
avoid impacts to Sugar Creek during the installation of this feature.
5.) 'Page 41—Stream Impact S15 — rip -rap apron location and topography in close proximity to Sugar Creek."
The culvert and riprap dissipator pad associated with proposed Stream Impact 14 and 15 have been designed to
maintain the natural dimension, pattern, and profile of the stream. The riprap dissipator pad associated with Stream
Impact 15 is located within a section of stream that is actively eroding and is intended to address velocity and channel
degradation. The terminus of the proposed riprap pad is at grade with a stable section of stream and avoids additional
impacts to Sugar Creek.
Map Comments
1.) Impact Map Sheet 4
Comment 1: "Revise plans to remove black background."
An uncorrupted file/plan set was uploaded to a sharefile link and submitted on August 2, 2023, via email.
Comment 2: "Is span length maximized... Is there opportunity for longer span to avoid impacts?"
The are no impacts associated with the proposed pedestrian bridge. Stream bank stabilization is proposed for incised
banks located beneath pedestrian bridges to prevent erosion. The bridge structure will shade these areas and may not
support vegetation that would otherwise provide bank stability.
Comments 3 & 4: "Is energy dissipation at the end of this ditch prior to flow entering creek?"
Energy dissipation pads are not proposed for the ends of the referenced ditches. The ditch designs were based on
drainage calculations for a 10-year storm event and fall within the non -erosive velocity of a grass -lined ditch, as
proposed. A copy of the ditch calculations is attached.
2.) Impact Map Sheet 5
Comment 5: "Can alignment not be pulled back from steep slope? Is this alignment determined by existing bridge over
Sugar Creek?"
The current alignment is at least approximately 30 feet from an unnamed tributary to Sugar Creek and at least
approximately 50 feet from Sugar Creek. The alignment was designed to reduce stream impacts to the maximum extent
practicable within the space provided by the easement parcels.
Comment 6: "Has approval been obtained from FEMA for floodway encroachment?"
An approval from the local floodplain manager with Charlotte -Mecklenburg Stormwater Services is anticipated before
the design is finalized.
Comments 7 & 8: "Remove black so staff can provide appropriate review."
Please reference the response to Comment 1, access to maps without the black markup were provided on August 2nd
3.) Impact Map Sheet 6
Comment 9: "Remove black background..."
Please reference the response to Comment 1.
Comment 10: "Any opportunity for longer span to reduce impact?"
Please reference the response to Comment 2.
4.) Impact Map Sheet 7:
Comment 11: "Remove black background..."
Please reference the response to Comment 1.
5.) Impact Map Sheet 12:
Comment 12: "What is the significance of this green dot and line? Is there a wetland here that is not shown completely?"

The line represents the western side of a linear wetland that was avoided.
6.) Impact Map Sheet 13:
Comments 13 & 14: "Can pump around not be located on E side of trail to avoid impact?" and "Can pump around not be
located on high ground during construction?"
Culvert replacement will occur via an open cut trench method. The pump around as proposed mimics the current
drainage of water from the headwater wetland to stream and ensures a dry work area for setting the invert within the
wetland at the appropriate/existing elevation. Proposed impacts associated with Impact W1 for the pump
around/access area include temporary measures like sandbags that assist the pump around apparatus.
7.) Impact Map Sheet 15:
Comment 15: "Any drains proposed for this bridge? If so, where?"
There are no drains proposed for the bridge.
Comment 16: "Is this bridge at 0 grade? How will it drain?
The bridge will be pitched at a two-inch height difference from one end of the bridge to the other. Sheet flow will drain
across the concrete bridge deck and downgradient to the greenway trail.
8.) Impact Map Sheet 17:
Comment 17: "Should there be a detail for this outfall? It does not appear to be an existing defined conveyance."
Please reference the response to comment number 4) under Avoidance and Minimization above.
9.) Impact Map Sheet 18:
Comment 18: "Is this 18" adequate? Topo illustrates a significant conveyance."
The topography within this area is representative of its use to drain a former parking lot associated with the Charlotte
Coliseum. The ditch no longer receives concentrated flow, and the proposed culvert has been designed to meet the
stormwater needs associated with greenway use.
10.) Impact Map Sheet 19:
Comment 19: "Remove black background..."
Please reference the response to Comment 1.
11.) Impact Map Sheets 20 & 21:
Comments 20, 21 & 22: "Remove black background..."
Please reference the response to Comment 1.
12.) Impact Sheet 22:
Comment 23: "How is transition from cut to fill being handled? Is there enough flow to warrant rip rap, etc.?"
A retaining wall is situated upslope of the greenway trail limiting the drainage area. Stormwater and minimal retaining
wall drainage will sheet flow across the well -vegetated slopes above and below the trail.
13.) Impact Map Sheet 23:
Comment 24: "Are there options for longer span to reduce impacts?"
Please reference the response to Comment 2.
14.) Impact Map Sheets 24 & 25:
Comment 25 & 26s: "Remove black background..."
Please reference the response to Comment 1.
15.) Impact Map Sheet 26:
Comment 27: "Where is closure for these WLBs?"
This portion of wetland is representative of a linear wetland ditch.

Comment 28: "Remove black background..."
Please reference the response to Comment 1.
16.) Impact Map Sheet 27:
Comment 29: "Remove black background..."
Please reference the response to Comment 1.
17.) Impact Map Sheet 29:
Comment 30: "Where is the inlet to this 64" RCP? Has flow been accounted for in design?"
The inlet to the 64" RCP is located upslope off Memorial Parkway and National Avenue and is associated with an existing
residential community and Aloft hotel. Flow from this outlet has been accounted for in the design and alignment of the
proposed greenway. Stormwater from the outlet currently accesses a wetland and gently distributes the outflow within
the shallow contours of the area, which eventually diverts away from the greenway trail. Additional measures, including
a spill bridge, have also been proposed to provide additional relief if needed.
18.) Impact Map Sheet 30:
Comment 31: "Remove black background..."
Please reference the response to Comment 1.
19.) Impact Map Sheet 32:
Comment 32: "Remove black background..."
Please reference the response to Comment 1.
Comment 33: "Has flow in cut sections been addressed?"
Please reference the response to Comment 23.
20.) Impact Map Sheet 33:
Comment 34: "Does flow in cut section have relief?"
Please reference the response to Comment 23.
21.) Sheet C2.00:
Comment 35: "Has the City of Charlotte approved a Stormwater Plan for this increase in BUA?"
The City of Charlotte will review and approve the stormwater management plan prior to the project's construction.
22.) Sheet C3.00:
Comment 36: "Is there not a proposed stormwater treatment device for this site plan?
There is no stormwater treatment device for this component of the project. Please reference the attached Built Upon
Area (BUA) exhibit. The built upon area for the trailhead/parking lot totals 15.4% of impervious area, which is below the
24% threshold requiring a stormwater treatment plan/device per the City of Charlotte.
Jennifer Burdette
Natural Resource Consultants
New Address:
308 W Millbrook Rd, Ste D #200, Raleigh, NC 27609
burdette(@nrconsultnc.com — 919.422.3605
Natural Resource
Consultants
From: Conchilla, Ryan <[e-mail]>
Sent: Wednesday, August 9, 2023 10:32 AM

To: Kaylie Yankura <[e-mail]>
Cc: Jennifer Burdette <[e-mail]>
Subject: 20230942_Sugar Creek Greenway_Mecklenburg Co.
Hi Kaylie,
Thank you for sending the updated plan sets.
I'm following up on responses for the comments provided on 7/31/23.
Let me know if I can provide additional support at this time.
Thanks
Ryan Conchilla, PWS
Environmental Specialist II
401 and Buffer Transportation Permitting Branch (DOT Divisions 7+8)
Division of Water Resources, NC Department of Environmental Quality
919-707-9111 office
[e-mail]
D- E
�
NORTH CAROLINA kipi
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.
From: Kaylie Yankura <[e-mail]>
Sent: Wednesday, August 2, 2023 10:44 AM
To: Conchilla, Ryan <[e-mail]>; Jennifer Burdette <[e-mail]>
Subject: RE: [External] RE: 20230942_Sugar Creek Greenway_Mecklenburg Co.
CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the Report Message
button located on your Outlook menu bar on the Home tab.
Hi Ryan,
Thanks for uploading the impact map comments. We're working on addressing your avoidance and minimization
questions, as well as the comments on the impact sheets and will have a response to you soon. In the meantime, it looks
like the maps were corrupted during upload with the PCN application (probably due to file size), which is why there are
black areas Susan marked as unable to review. I've uploaded the maps at the link previously used below, the file is
labeled 2023-06-13 Sugar Creek Greenway_lmpact Maps, which should be free of any blacked out/unviewable areas.
Please let me know if you have any additional questions/comments or if there are any issues accessing the file.
Thanks,
Kaylie Yankura
Natural Resource Consultants
New Address:
308 W Millbrook Rd, Ste D #200, Raleigh, NC 27609

[e-mail] — 724.994.8917
izem.
atural Resource
nnsulkants
Law and may be disclosed to third parties by an authorized state official.