R-3300B Update on 1_23_23 Erosion Issues

From:Gingrich, Sophia E
To:Sprinkle, Hannah H; Steffens, Thomas A CIV USARMY CESAW (USA)
Cc:Westphal, Anneliese; Farrell, Sean C
Subject:R-3300B Update on 1/23/23 Erosion Issues
Date:Monday, January 30, 2023 12:51:41 PM
Attachments:42in pipes.jpg
78in inlet.jpg
Air Bridge.jpg
Filling Old JS.jpg
Old JS Entry.jpg
Rock check at 42in.jpg
Upstream of 78in (1).jpg
Upstream of 78in (2).jpg
Upstream of 78in.jpg
Tom and Hannah,

I wanted to provide an update for you on the loss and erosion issues we had last week at the bypass.
I’m sorry it took so long to get you an update. The 42” pipe inlet at Y32 Sta. 18+00 was the only
location they had a loss in the active stream. The other locations included in Ben’s email on 1/23 are
ditches that drain to/connect to the active stream or, in the case of the air bridge, occurred in the
old stream that is no longer active. When I visited the site last week, they had cleaned out the
sediment in the inlet of the 42” pipe down to 4 inches below the water level. The plan was to get
more out when the water went down. The sediment came from the bank of the ditch that runs along
US 17 and connects to the stream at the inlet of the 42” pipes. The sediment was in and in front of
the inlet of the 42” closest to the ditch. Water in the ditch got under the fabric next to the rock
check and washed out some of the wall of the ditch. They estimated about 2 cubic yards of material
washed out. They had already fixed the fabric and rock check last week. I believe they decided to
remove the rock check, but if not, I did ask them to replace the dirty stone.

The connection of the old stream that ran under the air bridge to the new stream had been sand
bagged (see “Old JS Entry”), so there was no longer any connection between the two. They were
actively filling in the old stream, starting upstream of the air bridge and working their way to where
it used to connect to the now active stream. They are planning on pumping the water left in the
channel into a basin.

The ditch upstream of the 78” pipe had some erosion issues as well. This location was up near the
outlet of the 48” CAAP at Y32 Sta. 29+40. They had washing around and under the silt fence where it
met the rock check. They were going to remove a little more material from the ditch and extend the
rock past the end of the silt fence so there would be more overlap. They also planned on adding
hardware cloth and making it a special sediment control fence instead of a rock check.

I do not have any pictures of the side ditch washout at Y32RPBI that connects to the outlet of the
78” pipe. I checked in with Jim, and he said that this area had been cleaned up too.

At the time of my visit, they had not done anything to fix the elevations of the 78” pipe or backfill
culvert 10. They had put in 18-20 slope drain along the fill slopes that outlet in the side ditches which
drain to the outlet and inlet of the 78” pipe to help direct runoff from the fill into the ditches. In the
picture titled “78in inlet” the rock you can see up in the side ditch is an outlet of one of these slope
drains.

We can check out these sites during our ride through this week. If you have any questions before
then, just let me know.

Thanks,

Sophia Gingrich
Environmental Specialist I
Division 3
NCDOT – Division of Highways

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