20130918 Ver 11_U-2525C Site 10 sediment Loss_20201106

Wanucha, Dave
From:Parker, Jerry A
Sent:Friday, November 6, 2020 3:55 PM
To:Wanucha, Dave; [e-mail]
Cc:'[e-mail]'; Harper, Aaron A; Eason, Patty P; Knowles, James S; Julian, Jason R;
Childress, Donald W; Josh Pratt
Subject:U-2525C Site 10 sediment Loss
Attachments:Sediment Removal Guidelines.pdf; U-2525C Site 10 Pictures.docx

This email is to make you aware of sediment loss at Site 10 on U-2525C in Guilford
County. The loss occurred beneath and downstream of a temporary stream
crossing which is being utilized for transporting dirt from an approved borrow site.
The source of the loss could not be definitively determined since all of the nearby
devices appeared to be functioning properly. So due to the sediment appearing
downstream from the crossing with no significant sediment appearing upstream of
the crossing, it was concluded that the loss must have come from the temporary
stream crossing (see pictures). Even though soil is removed from the crossing
prior to any anticipated rain event, it is assumed that runoff carrying sediment
likely entered the stream from the location of the crossing. Based on that, the
contractor has been instructed to first remove the accumulated sediment in the
stream for a distance of approximately 70 ft beginning beneath the temporary
crossing and extending downstream. I have attached sediment removal guidelines
which will be followed during the removal process. The contractor is then
instructed to clean out and replace as needed the geotextile underlaying the
temporary crossing, retrieving any project material that migrated under the
temporary crossing and cleaning off the temporary crossing deck per the directives
of the Roadside Environmental Engineer. The contractor was also directed by the
Engineer to re-settle the wattles along the temporary crossing deck to good
working order and establish temporary stabilization of the slopes along the haul
road. In addition, diversions are to be re-established daily and in advance of
forecasted rains across the haul road. The contractor is also instructed to remove
the Class B riprap on the bank downstream of the crossing and replace with larger
Class 1 riprap underlain with filter cloth to further stabilize that bank. The wattle
barriers should then be re-installed along the toe of the slope of the new riprap.

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Please let me know if you have any questions or comments concerning this matter
or if you have any further recommendations.

Jerry Parker
Environmental Supervisor
Division 7
North Carolina Department of Transportation

336 256 2063 office
[e-mail]

1584 Yanceyville St.
P.O. Box 14996
Greensboro, NC. 27415-4996

Email correspondence to and from this sender is subject to the N.C. Public Records Law and may be disclosed to third parties.
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