20161220 Ver 2_I-5000 Permit Re-Verification Information Request_20210625

Carpenter,Kristi
From:Steve Kichefski
Sent:Friday, June 25, 2021 3:52 PM
To:Turchy, Michael A
Cc:Hood, Donna; Matthews, Monte K CIV USARMY CESAW (USA)
Subject:\[External\] I-5000 Permit Re-Verification Information Request
Attachments:RE: I-5000 Gaston County; \[Non-DoD Source\] Re: I-5000; RE: I-5000
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Mr. Turchy
As per our discussion Friday, June 18, 2021, we have received NCDOT’s request for project authorization renewal for the
Improvements to the I-85 and US 321 Interchange in Gaston County, Federal Aid Project No. IMF-85-1(113) 17, Division
12, TIP No. I-5000. Verification was originally authorized under Regional General Permit SAW-198200031 (RGP 31) on
January 31, 2017 with the USACE Action ID# SAW-2010-00033. The GP31 verification expired on April 30, 2020 and on
April 21, 2021 we received your renewal request under Regional General Permit SAW-2019-02350 (RGP 50) due to the
project being incomplete.

Portions of this interchange project involved culvert construction near existing culverts for I-85. The stream bed in these
areas contained sedimentation that proved problematic for the new culvert construction and the NCDOT met with
agencies multiple times to work through these issues prior to the original authorization. The resolution agreed upon was
the removal of Rankin Lake Road bridge and a man-made cascade directly downstream of the bridge (which was seen as
the major barrier to flushing this sediment), authorizing dredging throughout a short section of channel in order to
accommodate one of the culvert extensions (Site 1) and reconfiguring the culverts with benching and sills to route base
flow thru one of the three culvert barrels in an effort to create normal channel dimensions (thalweg scour/sediment
flushing). During the project construction the culvert extension was dredged and installed but quickly filled with
sediment, reducing capacity by over 60 percent. These culvert conditions have persisted for several years in a large part
due to Rankin Lake Road not being removed within the timeline requested by agencies. Due to continued agency
concern for this area of the project, NCDOT had additional modeling done to determine the best course of action for this
stream reach. NCDOT’s final recommendation based on this modeling is still unclear, but seemed to at least involve
floodplain grading.

At the time of the NCDOT request for permit renewal, project construction is incomplete, however prior to USACE
authorization additional information is needed to understand the remaining work to be completed, a timeframe for this
work and whether the design has changed (or needs to be changed) to resolve some of the issues identified on the
project. I have attached several emails documenting the most recent project correspondence from 2019.

1. What work within jurisdictional areas are needed in order to complete the project as submitted? When do you
anticipate this work will be completed?
2. Have all impacts already constructed within jurisdictional features been completed in accordance with the
design authorized by the January 31, 2017 verification?
a. Was the Site 1 culvert extension elevation installed in accordance with plans? There has been previous
discussion that the outlet elevation was potentially installed at a lower elevation which could increase
the problem of sediment flushing downstream of this culvert.
b. Were benches and sills for Site 1 constructed in accordance with plans submitted with the original
permit application and what is the current sediment depth sitting in the culvert (and over sills/benching
if constructed)?
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3. There are some unanswered questions regarding final design and function for the stream channel from the
outlet of Site 1 thru the natural rock formation downstream of the bridge.
a. Last update provided by NCDOT in 2019 indicated, based on modeling, that floodplain grading would
help improve the attempts to lower sedimentation in this reach and provide a normal functioning
channel dimension (with thalweg) as to the current wide, flat, sand bed channel present. Has the
floodplain grading been completed to this design recommendation? If not, is it still the recommendation
and when will it be completed?
b. Were other recommendations made based on this model?
c. What is the timeline for the removal of the Rankin Lake Road bridge and is the man-made cascade
immediately downstream of the bridge also to be removed? If not, is the elevation of the cascade
causing increased sediment elevations in this area or the Site 1 culvert?
d. What extent is the combination of the floodplain grading and the Rankin Lake Road bridge removal
expected to lower the sediment elevation in this reach of stream and how much sediment is anticipated
to stay within the culvert?
e. In my April 1, 2019 information request email, during our August 22, 2019 project meeting and in my
September 16, 2019 information request email I asked for clarification as to whether the Site 1
benching/sills will be functioning as designed and agreed upon during pre-application meetings based
on channel sedimentation (base flow in one barrel in order to provide more appropriate dimension). It is
still not clear to me if the sediment elevation within this stream reach and culvert Site 1 will be above
bench and sill height based on the presence of natural rock downstream of Site 1.
i. Are bedrock formations downstream of Site 1 going to hold sediment elevations higher than the
existing culvert outlet elevation? What height?
ii. Are any bedrock formations proposed for removal at this time in order to flush sediment? Will
they be accessible if further work is needed on them later?
iii. Is NCDOT recommending design changes to the bench or sill elevations at Site 1 in order to
maintain baseflow through a singe barrel of the triple barrel culvert?
iv. Is there any reason why NCDOT believes base flow through a single barrel is incorrect for
reaching appropriate channel dimension or not attainable at this point?
v. Will Site 1 meet permit conditions GP50 Special Condition 1(d) Culverts and Pipes. If not, please
explain why and what design NCDOT believes to be appropriate.
4. The initial permit verification included monitoring requirements to ensure that the Site1 thru Rankin Lake Road
bridge project reach is constructed to meet agency expectations and permit conditions. Monitoring conditions
will be required in the permit re-issuance and if this reach does not adjust appropriately, additional actions may
be required.
a. Have any initial monitoring steps already been set up (cross sections, photo stations, bank pins, etc.)?
b. What monitoring and timeline does NCDOT propose in order to adequately ensure that channel
conditions meet agency requirements?
c. Who is proposed to complete monitoring in this project reach (Div12, Central Office, consultant, etc.)?
5. Has all compensatory mitigation been paid in accordance with Special Condition 1 and the Mitigation
Responsibility Transfer Form accompanying your January 31, 2017 permit verification? Please provide a copy of
the MRTF signed my DMS.
6. At Site 6, the 3-sided culvert (Conspan) installed under Bulb Avenue, no permanent impacts within the Conspan
were proposed or authorized based on initial project design. After discovering a bedrock stream in this location
and the pre-constructed Conspan to be too narrow to entirely avoid the stream, some impacts seemed likely to
occur in this project location. Provide a brief description of impacts that occurred and an estimate (linear
footage) of permanent impacts within the Ordinary High Water Mark of the stream associated with this culvert.
Pictures of the inside of the completed culvert would be helpful if available.

At this time, the request to utilize GP 50 for authorization of impacts to waters of the U.S. is on hold until the above
additional information has been received. If the information is not received by July 26, 2021, the Corps will withdraw
the permit request.

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Feel free to contact me with questions on this matter.

Regards,

Steve Kichefski
Regulatory Project Manager
U.S. Army Corps of Engineers
Wilmington District, Asheville Field Office
151 Patton Avenue, Suite 208
Asheville, NC 28801
(828)-271-7980 Ext. 4234
(828)-933-8032 cell

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