20190089 Ver 1_Watauga Bridge #83 bank failure_20200324

Wanucha, Dave
From: Hining, Kevin J
Sent: Monday, March 23, 2020 2:34 PM
To: Beckwith, Loretta A CIV USARMY CESAW (USA); Wanucha, Dave
Subject: Watauga Bridge #83 bank failure
Attachments: 2019-01984, NWP VL (signed), Bridge 83, Watauga Co.pdf, 401 Cert for Bridge 83 on
SR 1340.pdf, post construction prior to flood eventjpg; after the flood event in
Februaryjpg; rip rap addition at Watauga bridge #83.pdf
Hey Dave and Lori,
Last fall, we completed a bridge project in Watauga County — Bridge #83. Dave, you visited the site with me on
10/17/19. Despite finishing the project late in the year, we were able to get some vegetation growing on the newly
sloped banks located upstream of the new bridge. However, a flood in February undermined both banks. As a result,
we need to add rip rap to stabilize the banks. We plan to only put rip rap at the toe of the bank, leaving the existing
vegetation and coir fiber matting. This will help narrow up the stream channel (mimicking conditions upstream and
downstream of the site), and will stabilize the banks against future storm events. Also, since we are only putting rip rap
at the toe of the bank, trees and shrubs will hopefully take root on the un-armored portions of the bank and provide
shade.
I've attached photos of the site —1) a couple months post construction when it was in good shape, 2) after the flood
event showing the issue, and 3) a depiction of what we would like to do. I've also attached the 401 permit and the
modified 404 (we had a modification to the permit, involving a channel change) for reference.
I visited the site and took measurements earlier today, and we are in need of an additional 15 ft of riprap (we will be
applying more than that, but from a permit standpoint, we only need 15 ft). I'm not sure if this requires a new permit, a
permit modification, or just something to note in your files. The stream is naturally very rocky, and like most high
gradient Watauga County streams, the banks are typically hardened by natural rock throughout. We installed a
temporary detour pipe where the issue occurred, so much of the natural rock that occurred at the site may have been
removed in order to get the pipe in place. That's all to say that the area in question was likely hardened naturally prior
to the construction of the project. However, I wasn't around back then, so I do not have photos of the banks pre -
construction to support that possibility.
I'm more than happy to provide whatever additional information you might need. Also, if I need to fill out a PCN, or
other formal process, just let me know.
PS — NCDOT has asked me to work form home for the time being, to limit the number of employees in the building.
have email access, but best to call my cell if you need to speak to me in person.
Thanks!
Kevin
Kevin Hining
Division 11 Environmental Officer
North Carolina Department of Transportation
336 903 9129 office
828-386-7202 cell

k . j1hininggLncdoI:.-qoy
801 Statesville Rd.
PO Box 250
North Wilkesboro, NC 28659
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