20161220 Ver 2_USACE Site Visit Comments_20190401

Carpenter,Kristi
From:Steve Kichefski
Sent:Monday, April 01, 2019 8:53 AM
To:Hood, Donna; Dagnino, Carla S; Barrett, William A; Conner, Eric W; Grigg, Justin T
Cc:Braspennickx, Nicholle M CIV USARMY CESAW (US); Beam, Patricia; Wyatt, Jeffrey L;
Carpenter, Larry S; Matthews, Monte K CIV USARMY CESAW (USA); Chambers, Marla J;
[e-mail]
Subject:RE: I-5000 Gaston County
Attachments:I-5000 Stream Profile Exhibit_2016-06-03_print.pdf; I5000-Site1CulvertSediment_
20190326.jpg
All,
I also agreed to send an email regarding our site visit Tuesday and current project concerns. As Donna mentioned, we
visited I-5000 on Tuesday, March 26th due to concerns about the amount of sediment that immediately accumulated in
the 3@8' x 9' box culvert (Site 1) post- construction and whether this sediment will move through the system as
originally planned. I attached a picture of this culvert taken during Tuesday's visit.

Here is a quick summary of the project issues within this area based on my files. The merger team had several meetings
regarding the accumulated sediment in this area prior to permitting and the various requests for dredging it out (I'm
ignoring the issues with the unknown adjacent landfill for today's discussion). The permitting and resource agencies had
several concerns with dredging, including whether this was a natural sand bed stream, what the appropriate
streambed/culvert elevations should be throughout this reach, why the sediment was not moving through the system
and how the channel/stream banks might adjust afterwards. After various assessments, NCDOT and Kimley Horn
determined that there were many disturbed/eroding stream banks contributing sediment within the watershed and
believed that the channel constriction caused by the Rankin Lake Road Bridge coupled with a man-made and natural
rock formation immediately downstream of the bridge were holding sediment from moving thru the system. I attached
the June 3, 2016 stream profile exhibit, one of the many documents provided during those meetings. The agency's
strongly recommended removal of the Rankin Lake Road Bridge at the beginning of project construction to let the
sediment flush as proposed instead of dredging, however NCDOT insisted that it could not be removed until later in the
project sequence after the Bulb Avenue construction was completed. A compromise was reached to let a smaller
amount of dredging occur immediately downstream (with monitoring) of the Site 1 culvert extension and the rest would
flush after the Rankin Lake Road impacts occurred.

During our site visit Tuesday, we verified that the approved construction plans cannot be completed until the sediment
accumulation is addressed. There are three to four feet of sediment over the top of the two foot sills installed at the Site
1 culvert outlet. This prevents the outlet benching and lateral base ditch outlet from being constructed according to
plans and keeps the base flow from being directed through just one culvert as agreed to during merger in order to help
flush sediment from the culvert and stream channel.

We recognize that the proposed work removing the bridge and rock formations immediately downstream have yet to be
completed and may still improve the situation. We also recognize that project plans did not call for all sediment to be
flushed from the culvert after project completion, however, we are concerned about the capacity of the culverts until
the improvements are made. If 5-6 feet of the 8 foot culverts are filled with sediment, we are concerned about what
storm events could do to the structural integrity of the culverts and potential flooding to the upstream properties.

Also, during the site visit Tuesday there was concern expressed about potential bedrock within the stream channel
between the Rankin Lake Road Bridge and Site 1 that was high enough in elevation to prevent the sediment from
flushing as originally proposed.

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Please provide us with the following information:

1) What level of sediment in the culverts was submitted when obtaining the CLOMR for the National Flood Insurance
Program and do you still anticipate they are correct?

2) Are there additional obstructions between the Rankin Lake Road Bridge and Site 1 that would prevent the sediment
from flushing as proposed? Provide the contractor and any additional Div12 surveys for verification on this reach of
stream. Were the original surveys done in a manor sufficient to determine the elevation or are additional investigation
needed in this area to ensure the stream elevations originally proposed?

3) Do you still anticipate completion of Site 1 and Site 5 as permitted? If three feet of sediment are expected to remain
in the culverts how will the culvert benching be constructed at a two foot depth and how will the base flow of the
stream be directed into just one pipe instead of spread out across all three culverts?

4) What is the current timetable for of the completion of construction around Rankin Lake Road Bridge, including its
removal and the channel alterations in this area? Do you have concerns regarding the current culvert capacity as
mentioned above during this timeframe?

5) How deep is the utility line crossing the creek near Rankin Lake Road and will it have sufficient cover if the channel
sediment is flushed as proposed? Will its elevation affect the flushing of the sediment in this area as proposed?

Feel free to contact me with any questions.

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

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-----Original Message-----
From: Hood, Donna \[mailto:[e-mail]\]
Sent: Wednesday, March 27, 2019 6:09 AM
To: Dagnino, Carla S <[e-mail]>; Barrett, William A <[e-mail]>; Conner, Eric W
<[e-mail]>; Grigg, Justin T <[e-mail]>
Cc: Braspennickx, Nicholle M CIV USARMY CESAW (US) <[e-mail]>; Kichefski, Steven L
CIV USARMY CESAW (US) <[e-mail]>; Beam, Patricia <[e-mail]>; Wyatt, Jefffrey L
<[e-mail]>; Carpenter, Larry S <[e-mail]>
Subject: \[Non-DoD Source\] I-5000 Gaston County

All,

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Yesterday we had a site visit at I-5000 to discuss problems with the site. The current site conditions show that the new
extension on the culvert under I-85 currently has 4-5 feet of sand in an 8 foot tall culvert. The construction company got
out of the stream 2 weeks ago and it filled in within those 2 weeks, just that fast.

Based on some preliminary findings of on-site personnel a few months ago, there is bedrock in the stream, the width of
the stream, and it is at a higher elevation than the bottom of the culvert. 2 feet higher. This is of great consequence
because it will prevent the stream from flushing the sand that currently fills the culvert, even when Rankin Lake Road
bridge is removed. This will not meet the CLOMAR and houses/properties upstream will be flooded. Current conditions
during rain events are already showing impacts by how much water cannot get through the culvert during storm events.
The current situation also will not meet 401 permit conditions. 6 feet of sand would have to be dug out of the stream
channel to install the benches. This is also the area of the stream that was going to show a postconstruction uplift.

Apparently bedrock location was not investigated during the site assessment for the merger and permitting processes.
Bill, if you know of anything done and I am remembering incorrectly, please help us out.

There were conversations on site several months ago about this problem and it is my understanding that the Division did
not move forward with further investigations. Larry and Eric, if I am wrong about that please advise because we are now
in a bit of a time crunch to address the problem before fill slopes encroach too much on stream access in some areas. It
is also my understanding that Div. 12 has surveyors available to help, as they did with the postconstruction site
assessment of the wetland at the Buffalo Shoals bridge.

To move forward there needs to be a thorough investigation of bedrock depths down the length of the stream channel
past the Rankin Lake Road bridge. Survey information gathered by the contractor indicates that break point in the
channel, where the elevation begins to be lower than the bottom of the culvert, is after the bridge.

Please be advised that bedrock depths cannot be determined by sticking a grade rod on top of the sand in the thalweg of
the stream, a probe rod must be used. Once we have more stream information, we can move forward with how to
correct the problem and modify the permit.

Eric or Tyler, if either of you could please share the preliminary bedrock grade information already gathered by the
contractor, it would be greatly appreciated.

I look forward to solving this problem. Bill, I am on I-485 today but will be available Thursday afternoon if you would like
to talk about this for more clarification.

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Regards,

Donna

Donna Hood - [e-mail]

North Carolina Dept. of Environmental Quality

Division of Water Resources

Transportation Permitting Branch

610 E. Center Ave.

Mooresville, NC 28115

Ph: 704.663.1699 Cell: 704.682.2839

Fax: [phone]

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