20180032 Ver 2_COE questions/answers_20201202

Strickland, Bev
From: Amschler, Crystal C CIV USARMY CESAW (USA) <[e-mail]>
Sent: Tuesday, December 1, 2020 11:19 AM
To: Tinklenberg, Chris
Cc: Johnson, Alan
Subject: [External] RE: SAW-2020-01148 Lower Little Sugar Creek ( CSWS)
• External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
report. spa mC•) nc.f,c
Chris,
Yeah apparently I just missed Charlotte so much I just couldn't stay away!
Thanks for your response to my questions. Below I've made my comments in Blue:
1) Tthe question of single and complete for this project discussed with Dave S and if so, do you have any
of the documentation from that discussion? The PCN indicates that this part of the Cross -Charlotte
Trail project and there are a couple of files in our database with that name. The plan shows the
termination on the western end of the project with the greenway connecting with what appears to be
a future greenway and a note that there will be a "future Greenway Connection by others". The
eastern end connects to the project that was permitted under SAW-2018-01818 and issued
September 2018. Please provide any documentation on previous discussion of whether this project is
single and complete, and if there has been no previous discussion please provide justification that this
segment is single and complete from other segments.
This was discussed many years ago during the Tyvola to 1-485 section of the XCLT trail as well as ANY trail that
is part of a larger greenway system. Dave communicated that under NWP 14, each crossing would be
considered single and complete, however, the threshold for mitigation had been met and ALL impacts require
mitigation unless the greenway trail is not part of a larger network. Spans, slab -top bridges, and top -down
constructed boardwalk are all implemented where practicable and feasible. I do not have any formal
correspondence on this. It was just understood that all impacts moving forward, for most greenway projects,
would require mitigation.
Thanks for your response. I coordinated with David S and Bryan and they both confirmed the permitting
mechanism for this project.
2) The rock toe: Typically rock toes aren't as preferred as other natural stabilization measure and I often
see them designed using large boulders that would restrict flow, and as Alan pointed out in an email
correspondence sent with the original request, acts more as a retaining wall. However, the detail for
rock toes provided in the plan seems to show smaller rock (6-18") used along the toe of the bank and
sloped at what looks like more of a 2:1 slope. Can you verify that my interpretation of the plan is
correct and that the rock toe won't result in creating a vertical, restrictive barrier along the stream
bank?
You are correct. The rock -toe protection proposes to install 6"-18" riprap flush with the bank to provide a
stable rock foundation for the grading that is proposed to occur behind the rock and up the bank. Please note

that per the site walk on February 2, 2018, Dave Shaeffer identified an area of opportunity within a rock -toe
section (STA 27+50 — 28+50) and requested that we replace the rock -toe protection with a brush mattress
solution.
Thanks for your comments. I consider this issue resolved.
3) The plan sheets showing the bridge crossings indicate that sheets S4-S6 show bridge details, but I
didn't see these sheets in the plan. Please forward those to me. I'm particularly looking for
information that indicates there won't be any additional riprap in the stream associated with these
crossings as the plans indicate that class 11 riprap will be used with the bridge and references the "S"
sheets for these details.
In an effort to reduce the overall size of the planset, I mistakenly removed the "S" sheets from the compiled
set. I have attached this section for your reference.
Thanks for the plan sheets Chris. Still confused though. Looks like Structures 2, 3, 5, 6 and 8 all cross
jurisdictional features and all of these structures (except 8) show riprap along the banks or across the entire
creek on the plans, but I don't see that these riprap impacts have been captured in the table. Am I just
missing it? Also, assuming the plan accurately shows the riprap here in these areas, please indicate why
riprap would need to be placed within the streams or along the banks where bridge crossings will be
constructed.
4) From Dave's request for information sent in response to the 2018 permit request: "a typical for Wall
DID shown on Sheet 51. Please provide a typical detail." I also would like to see more info on the
retaining walls. The plans reference sheets RW1-RW22 for more detail on retaining walls but I was
unable to locate these plan sheets. Generally speaking, retaining walls are not desirable stabilization
measures compared to bank grading, vegetation and riprap. In the PCN you indicated that the
"Retaining walls are necessary in areas of extreme bank erosion where existing infrastructure, parking
lots, buildings need protection as well as areas where the greenway is close to the top of bank" and
the impact table proposes 1.205 If of impact due to retaining walls and grading. This is a lot of wall
and I think justification needs to be provided in each area where a wall is proposed. Further, in areas
where the wall is proposed due to the proximity of the greenway, then you should provide
information on why the greenway can't be moved further from the creek to allow for more natural
stabilization efforts. Also, NWP 3 doesn't allow bulkheads greater than 1,000 feet in length along the
bank so you should identify the length of the wall at each location.
I have attached the retaining wall plans for Walls AA, BB, CC, & DD for your reference. Please note that there
are other walls placed in upland areas around the site. These plans were not included to prevent any
confusion and reduce the attachment size.
Please refer to Figures 5a and 5b and the attached retaining wall plans. Retaining wall lengths and justification
for each reach are as follows:
• NCSAM Reach 1 (Wall AA) — 300 If
o Opportunity for solely bank grading and a more natural stabilization solution
is constrained at this location by an existing driveway and parking lots serving
the adjacent apartment home community. A near -vertical bank is present
immediately adjacent to the parking lot and poses an imminent threat to the
existing infrastructure and a safety concern for residents. The wall is
necessary to provide a stable toe and grade banks to a stable slope.

• NCSAM Reach 2 (Wall BB) — 157 If
o Similar to Reach 1, an opportunity for solely bank grading and a more natural
stabilization solution is constrained at this location by an existing driveway
and parking lot serving the adjacent apartment home community. A near -
vertical bank is present immediately adjacent to the parking lot and poses an
imminent threat to the existing infrastructure and a safety concern for
residents. The wall is necessary to provide a stable toe and grade banks to a
stable slope and is limited to only the most constrained location along the
meander bend.
• NCSAM Reach 3 (Wall CC) — 407 If
o Reach 3 & 4 are both extremely topographically constrained. From a
hydraulic perspective, it is not feasible to grade out into the stream without
significantly constricting the baseflow. The landward topography is too steep
and would be difficult to stabilize. The earthwork required to grade out to a
stable slope would likely encounter bedrock which would limit the ability to
provide the appropriate stabilization measures. The retaining wall along the
toe creates a solid, stable base and allows for a stable slope to be constructed
above. The stabilization activities at these locations are not constrained or
dictated by the proposed greenway alignment although, inherently, do
provide long-term protections of the greenway trail.
• NCSAM Reach 4 (Wall DD) — 341 If
o see above.
NCSAM assessments were performed at each location as directed by Dave Shaeffer in order to qualify for the
Corps' waiver. As mentioned in the attached 2/12/2018 email, the wall heights are limited to the minimum
necessary to provide a stable slope above resulting in heights ranging from 4'-5' at each location.
Thanks for this additional information Chris. I think it justifies the use of these retaining walls, and judging by
the pictures, this is a very degraded system that will benefit from stabilizing areas that are actively eroding
and resulting in excessive sedimentation downstream. as such, I think it may be better to lump these impacts
as NWP 27 impacts. We normally would not authorize retaining walls under NWP 27, but considering this
project includes a large aspect of stream improvement work under NWP 27, the retaining walls seem to be
placed minimally where other, less intrusive stabilization measures aren't feasible and that the retaining
walls, along with the overall project activities, should provide some benefit to the overall system, I think in
this case it is appropriate to issue these impacts under NWP 27.
5) Per NWP 13 requirements, please indicate how many cubic yards per running foot, as measured along
the length of the treated bank, below the plane of the ordinary high water mark will result from
stabilization that falls under NWP 13 for this project.
All proposed bank stabilization areas are no more than 0.7 cubic yards per running foot below
OHWM. I have attached the table indicating the volume of fill material below OHWM to this email.
Thanks for your comments. I consider this issue resolved.
6) For the purposes of notification that NLEB falls under the 4D rule, please indicate an estimate of acres
or numbers of trees that will be removed with this project. Didn't answer this question.
7) Looks like you forgot to answer this one? Any idea how much wooded area will be cleared with this project?

8) The cover letter indicates that a Preliminary Jurisdictional Determination (PJD) Request, Field Data
Forms, NCDWR Stream Identification Forms, NCSAM Forms and Agency Correspondences were
included with the packet but it looks like for whatever reason they didn't make it. the previously
submitted packet includes the JD information and agency information so if none of this information
has been changed then no need to resubmit. Please just verify I can rely on previously submitted
information. The previous package does not include the SAM forms so please forward those forms.
No changes to the PJD information but interesting that you didn't receive that info since it is all
compiled into one single pdf. Anyway, no changes to the JD information, you can rely on what was
previously submitted. I've attached the NCSAM forms and agency correspondence for reference.
Yeah it is weird, not sure what happened but thanks for re -sending.
9) Lastly, I seem to be missing some information from my file. The file associated with the withdrawn
2018 permit request has correspondence that indicates a field meeting took place, but I don't see any
follow up or field notes in the file. There are also emails in this file that bring up the rock toe and
retaining wall but I don't see that the concerns regarding these things were resolved. If there is any
information or document you have that would fill me in on any previous discussion on rock toes and
retaining walls, and that might help answer my questions above, please forward those to me. Also, if
you have any field meeting minutes that indicate what was discussed during the field meeting that
would be helpful as well.
An agency field review was conducted on February 2, 2018, with Dave Shaeffer, KH's stream
engineer Jason Diaz, and myself. Corresponding emails are attached for your reference.
Thanks for this additional information.
Sincerely,
Crystal C. Amschler
Project Manager
Asheville Regulatory Field Office
151 Patton Avenue, Room 208
Asheville, NC 28403
(828)-271-7980 Ext 4231
The Wilmington District is committed to providing the highest level of support to the public. To help us ensure we
continue to do so, please complete the Customer Satisfaction Survey located at:
http://corpsmapu.usace.army.mil/cm_apex/f?p=136:4:0
From: Tinklenberg, Chris <[e-mail]>
Sent: Thursday, November 5, 2020 9:54 AM
To: Amschler, Crystal C CIV USARMY CESAW (USA) <[e-mail]>
Cc: Johnson, Alan <[e-mail]>
Subject: [Non-DoD Source] RE: SAW-2020-01148 Lower Little Sugar Creek ( CSWS)
Hey Crystal! Welcome back to Mecklenburg County! Haha. I hope you've been well. Please see my responses to your
comments in red below.

If you have any other questions or need additional clarification, please let me know.
Thanks,
Chris
Chris Tinklenberg, PWS
Kimley-Horn 1200 South Tryon Street, Suite 200, Charlotte, NC 28202
Direct: 704 409 1802 1 Mobile: [phone]
From: Amschler, Crystal C CIV USARMY CESAW (USA) <[e-mail]>
Sent: Friday, October 30, 2020 1:57 PM
To: Tinklenberg, Chris <[e-mail]>
Cc: Johnson, Alan <[e-mail]>
Subject: SAW-2020-01148 Lower Little Sugar Creek ( CSWS)
Hi Chris,
I've reviewed the Lower Little Sugar Creek PCN and have the following comments:
1) Was the question of single and complete for this project discussed with Dave S and if so, do you have
any of the documentation from that discussion? The PCN indicates that this part of the Cross -
Charlotte Trail project and there are a couple of files in our database with that name. The plan shows
the termination on the western end of the project with the greenway connecting with what appears
to be a future greenway and a note that there will be a "future Greenway Connection by others". The
eastern end connects to the project that was permitted under SAW-2018-01818 and issued
September 2018. Please provide any documentation on previous discussion of whether this project is
single and complete, and if there has been no previous discussion please provide justification that this
segment is single and complete from other segments.
This was discussed many years ago during the Tyvola to 1-485 section of the XCLT trail as well as ANY trail that
is part of a larger greenway system. Dave communicated that under NWP 14, each crossing would be
considered single and complete, however, the threshold for mitigation had been met and ALL impacts require
mitigation unless the greenway trail is not part of a larger network. Spans, slab -top bridges, and top -down
constructed boardwalk are all implemented where practicable and feasible. I do not have any formal
correspondence on this. It was just understood that all impacts moving forward, for most greenway projects,
would require mitigation.
2) The rock toe: Typically rock toes aren't as preferred as other natural stabilization measure and I often
see them designed using large boulders that would restrict flow, and as Alan pointed out in an email
correspondence sent with the original request, acts more as a retaining wall. However, the detail for
rock toes provided in the plan seems to show smaller rock (6-18") used along the toe of the bank and
sloped at what looks like more of a 2:1 slope. Can you verify that my interpretation of the plan is
correct and that the rock toe won't result in creating a vertical, restrictive barrier along the stream
bank?
You are correct. The rock -toe protection proposes to install 6"-18" riprap flush with the bank to provide a
stable rock foundation for the grading that is proposed to occur behind the rock and up the bank. Please note

that per the site walk on February 2, 2018, Dave Shaeffer identified an area of opportunity within a rock -toe
section (STA 27+50 — 28+50) and requested that we replace the rock -toe protection with a brush mattress
solution.
3) The plan sheets showing the bridge crossings indicate that sheets S4-S6 show bridge details, but I
didn't see these sheets in the plan. Please forward those to me. I'm particularly looking for
information that indicates there won't be any additional riprap in the stream associated with these
crossings as the plans indicate that class 11 riprap will be used with the bridge and references the "S"
sheets for these details.
In an effort to reduce the overall size of the planset, I mistakenly removed the "S" sheets from the compiled
set. I have attached this section for your reference.
4) From Dave's request for information sent in response to the 2018 permit request: "a typical for Wall
DID shown on Sheet 51. Please provide a typical detail." I also would like to see more info on the
retaining walls. The plans reference sheets RW1-RW22 for more detail on retaining walls but I was
unable to locate these plan sheets. Generally speaking, retaining walls are not desirable stabilization
measures compared to bank grading, vegetation and riprap. In the PCN you indicated that the
"Retaining walls are necessary in areas of extreme bank erosion where existing infrastructure, parking
lots, buildings need protection as well as areas where the greenway is close to the top of bank" and
the impact table proposes 1.205 If of impact due to retaining walls and grading. This is a lot of wall
and I think justification needs to be provided in each area where a wall is proposed. Further, in areas
where the wall is proposed due to the proximity of the greenway, then you should provide
information on why the greenway can't be moved further from the creek to allow for more natural
stabilization efforts. Also, NWP 3 doesn't allow bulkheads greater than 1,000 feet in length along the
bank so you should identify the length of the wall at each location.
I have attached the retaining wall plans for Walls AA, BB, CC, & DD for your reference. Please note that there
are other walls placed in upland areas around the site. These plans were not included to prevent any
confusion and reduce the attachment size.
Please refer to Figures 5a and 5b and the attached retaining wall plans. Retaining wall lengths and justification
for each reach are as follows:
• NCSAM Reach 1 (Wall AA) — 300 If
o Opportunity for solely bank grading and a more natural stabilization solution
is constrained at this location by an existing driveway and parking lots serving
the adjacent apartment home community. A near -vertical bank is present
immediately adjacent to the parking lot and poses an imminent threat to the
existing infrastructure and a safety concern for residents. The wall is
necessary to provide a stable toe and grade banks to a stable slope.
• NCSAM Reach 2 (Wall BB) — 157 If
o Similar to Reach 1, an opportunity for solely bank grading and a more natural
stabilization solution is constrained at this location by an existing driveway
and parking lot serving the adjacent apartment home community. A near -
vertical bank is present immediately adjacent to the parking lot and poses an
imminent threat to the existing infrastructure and a safety concern for
residents. The wall is necessary to provide a stable toe and grade banks to a

stable slope and is limited to only the most constrained location along the
meander bend.
• NCSAM Reach 3 (Wall CC) — 407 If
o Reach 3 & 4 are both extremely topographically constrained. From a
hydraulic perspective, it is not feasible to grade out into the stream without
significantly constricting the baseflow. The landward topography is too steep
and would be difficult to stabilize. The earthwork required to grade out to a
stable slope would likely encounter bedrock which would limit the ability to
provide the appropriate stabilization measures. The retaining wall along the
toe creates a solid, stable base and allows for a stable slope to be constructed
above. The stabilization activities at these locations are not constrained or
dictated by the proposed greenway alignment although, inherently, do
provide long-term protections of the greenway trail.
• NCSAM Reach 4 (Wall DD) — 341 If
o see above.
NCSAM assessments were performed at each location as directed by Dave Shaeffer in order to qualify for the
Corps' waiver. As mentioned in the attached 2/12/2018 email, the wall heights are limited to the minimum
necessary to provide a stable slope above resulting in heights ranging from 4'-5' at each location.
5) Per NWP 13 requirements, please indicate how many cubic yards per running foot, as measured along
the length of the treated bank, below the plane of the ordinary high water mark will result from
stabilization that falls under NWP 13 for this project.
All proposed bank stabilization areas are no more than 0.7 cubic yards per running foot below
OHWM. I have attached the table indicating the volume of fill material below OHWM to this email.
6) For the purposes of notification that NLEB falls under the 4D rule, please indicate an estimate of acres
or numbers of trees that will be removed with this project.
7) The cover letter indicates that a Preliminary Jurisdictional Determination (PJD) Request, Field Data
Forms, NCDWR Stream Identification Forms, NCSAM Forms and Agency Correspondences were
included with the packet but it looks like for whatever reason they didn't make it. the previously
submitted packet includes the JD information and agency information so if none of this information
has been changed then no need to resubmit. Please just verify I can rely on previously submitted
information. The previous package does not include the SAM forms so please forward those forms.
No changes to the PJD information but interesting that you didn't receive that info since it is all
compiled into one single pdf. Anyway, no changes to the JD information, you can rely on what was
previously submitted. I've attached the NCSAM forms and agency correspondence for reference.
8) Lastly, I seem to be missing some information from my file. The file associated with the withdrawn
2018 permit request has correspondence that indicates a field meeting took place, but I don't see any
follow up or field notes in the file. There are also emails in this file that bring up the rock toe and
retaining wall but I don't see that the concerns regarding these things were resolved. If there is any
information or document you have that would fill me in on any previous discussion on rock toes and
retaining walls, and that might help answer my questions above, please forward those to me. Also, if

you have any field meeting minutes that indicate what was discussed during the field meeting that
would be helpful as well.
An agency field review was conducted on February 2, 2018, with Dave Shaeffer, KH's stream
engineer Jason Diaz, and myself. Corresponding emails are attached for your reference.
Thanks and fill free to give me a call if you'd like to discuss. my work mobile is 828-526-6013.
Crystal C. Amschler
Project Manager
Asheville Regulatory Field Office
151 Patton Avenue, Room 208
Asheville, NC 28403
(828)-271-7980 Ext 4231
The Wilmington District is committed to providing the highest level of support to the public. To help us ensure we
continue to do so, please complete the Customer Satisfaction Survey located at:
Blockedhttp://corpsmapu.usace.army.mil/cm_apex/f?p=136:4:0