USACE 09202023 Email Responses

From: Amschler, Crystal C CIV USARMY CESAW (USA) <[e-mail]>
Sent: September 20, 2023 4:09 PM
To: Breedlove, Patrick J <[e-mail]>
Cc: Mitchell, Robert K <[e-mail]>; McHenry, David G <[e-mail]>; Chris Rivenbark
<[e-mail]>
Subject: RE: R-5861 - Cherokee County - Additional Information & Email Responses 7.21.2023 & 8.1.2023

Hi Patrick,

I’ve reviewed the additional information provided on 8/22/2023. Below are some subsequent questions regarding this
information. As we discussed on the phone and suggested below, setting up a meeting to discuss some of these
questions might be a quicker way to get these issues resolved.

Comments/responses to the 8/1/2023 email

Regarding the permit type and relocation revisions: Thank you for the additional information. With the revisions and in
consideration of this information, we concur that this project qualifies for GP 50.
Thank you for confirming.

Regarding proposed mitigation for the stream relocations segments: The revised stream relocation design for stream
impact 1C now meets GP50s definitions and requirements for stream relocation. However, the additional information
provided on 8/22/2023 indicated the stream for 1C is 2’ wide but detail F, referenced for the stream relocation plan
shows a 4’ wide bed. Please address the discrepancy in the reported stream width and the relocation design width.
To meet hydraulic conveyance in this channel change, our ditch calculation spreadsheet requires a 4’ base to meet criteria,
detail F is correct. This revised channel change enters a 66” pipe before outleting into SA on the other side of DR1 which
shows a 3’ wide channel (riprap pad on the outlet of 66” will be benched property and coordinated to install riprap in a
manner to not over widen the channel).

You’ve proposed mitigating for the permanent impacts at Sites 1C & 23C at 1.5:1. Based on these impacts involving
stream relocation that includes some degree of uplift, we concur that mitigation for stream relocation impacts at 1.5:1 is
adequate at these locations. However, it appears that the new stream length would be shorter than the existing stream
length. Any loss of linear footage should still be mitigated at a 2:1 ration.
A footnote has been added to wetland summary impact table at the end of permit drawings to reference stream
(sinuosity) length loss in these two channels. See table and notes below for impact & mitigation details at these two
sites.
Site Original length w/ rip rap w/o rip rap Stream Loss
1C 403

225 162 16
23C 353 -- 253 100

The May 25, 2023 DMS Acceptance Letter provided mitigation for 3,013’ of stream impacts.
Assuming up to a 2:1 results in 6,026’ of credit provided by DMS.

Site 1C 403’ @ 2:1= 806’, though @ 1.5:1 only 580.5’ and stream loss @ 2:1 only 32’ is needed
Site 23C 353’ @ 2:1= 706’, though @ 1.5:1 only 379.5’ and stream loss @ 2:1 only 200’ is needed

3,013’-(225’+162’+253’)=2,373’ @2:1= 4,746’
225’+162’+253’=640’ @1.5:1= 960’
The revised mitigation required from DMS is 4,746’+960’=5,706’ which is still covered by the current DMS Acceptance
Letter. The Stream Impact table from the permit application has been updated to reflect the revised mitigation totals
and is included with this response.

Comments/responses to the 7/21/2023 email

Thank you for the additional information which satisfied the majority of my questions/concerns outlined in this
email. Below are some subsequent and/or remaining questions/concerns:

2) I cross-referenced the stream widths you provided with the proposed pipes at each location. Below are three crossings
that I had questions about as the pipe size doesn’t seem to match the widths of these streams. Please indicated how
stream widths will be maintained at the below crossings:

Site 23A: 2' wide outfall channel: 72” culvert for a 2’ wide channel
Site 23D: 2' wide infall channel: 60” culvert for a 2’ channel
Site 24: 5’ wide outfall channel: 30” culvert for a 5’ wide stream
The contractor will bench/riprap construct as to not over-widen channel and backfill with native material. Currently
coordinating a possible sill option with “weir cut out” at 72” crossing into 2’ wide channel as to not over-widen channel
inside the pipe. Other locations discussed during the 9/25/23 meeting and found acceptable as currently designed.

Comments/responses to plan comments submitted with the 7/21/2023 email

• Regarding detours: I think it would be more straight forward just to have a separate plan showing the detours
and impacts associated with detours. That will facilitate the review of the impacts and provide necessary
information to confirm that impacts associated with detours have been avoided and minimized to the extent
possible.
As mentioned during the 9/25/23 meeting, detour sheets (with colored jurisdictional resources) showing
proposed impacts only due to the detours are attached for reference.

Also, it appears wetland impacts resulting from the detours have been identified on the impact tables as
permanent: Site 3-WA, Site 5-WA. All temporary impacts to wetlands resulting from the detour should be
restored to preconstruction condition once the detour is removed. Please address this and revise the
wetland impact as necessary.
These sites will remain as total takes due to wetland size as discussed at the 9/25/23 meeting.

• Permit Drawing Sheet 16/17 of 50: I still have questions regarding this design. I suggest we set up a meeting to
discuss.
Discussed during the 9/25/23 meeting.

• Permit Drawing Sheet 23 of 50 and Permit Drawing Sheet 36 of 50: CSRs for this project were not provided with
the PCN. I have the CSR for Site 11 because dave had previously provided one back in 2020. Please provide an
updated CSR for site 11 and the CSR for Site 20 and any other CSRs that were created for culverts on this project
if any.
Previously provided.

Also, there still seems to be confusion on what I’m asking for regarding riprap and backfill in the low flow
culvert. We are asking that the details be revised to indicate that supplemental riprap should be used as needed
in the low flow channel, along with native material, where there isn’t enough native material to ensure complete
backfill. I’m also wondering if the CSRs will be provided to the contractor during construction for reference? If
not, then the main plan set should also include this information to ensure that the contractor is fully aware of
how the backfill and the culverts should be constructed.
A note has been added to the plan view and detail sheet.

• Permit Drawing Sheet 39 of 50: I still have questions regarding this design. I suggest we set up a meeting to
discuss.
Discussed during the 9/25/23 meeting.

• Permit Drawing Sheet 41 of 50 Permit Drawing: Why don’t you want to change the existing channel at the pipe
invert? It might be better for the system to step the upstream segment of the stream down a bit to tie into the
culvert at a lower elevation to flatten the pipe out a bit. This may result in additional impacts to the stream
but these impacts may be outweighed by the benefit from flattening out the culvert. This is another one that
might be good to discuss via a meeting.
Revised drainage design to straighten pipe under DR19 and revised grade on proposed channel from outlet of
60” to entrance of 72”. 60” pipe is now at 2.3% instead of 8% as previously shown – no additional impacts are
needed for this revision.

• Permit Drawing Sheet 44 of 50: I still have questions regarding this design. I suggest we set up a meeting to
discuss.
Discussed during the 9/25/23 meeting.

• Utility Permit Drawing Sheet 2 of 6 and Utility Permit Drawing Sheet 4 of 6: Please revise the plans to remove the
guy wire from the stream. Its fine to show a temporary impact in case construction requires it, however, the guy
wire should not be shown in the stream as we wouldn’t expect the guy wire itself would impact or need to be in
the stream and so the plans should be clear that the impact is not from the guy wire but potentially from
construction to install.
The guy wire was shifted out of stream to ensure it is constructed correctly.

Sincerely,
Crystal C. Amschler
Project Manager
Crystal Amschler
WRDA-Transportation Permitting Branch
828-526-6013