NC0003573_Plan of Action_20201218

Strickland, Bev
From: Grzyb, Julie
Sent: Thursday, December 17, 2020 4:08 PM
To: Allen, Trent; Brantley, Mark; Chernikov, Sergei; Hill, David A
Cc: Poupart, Jeff, Wojoski, Paul A
Subject: Fw: [External] Chemours 003 Sediment Removal Work Plan
Attachments: Chemours - 003 sediment action - 12_16_2020 -final (3).pdf
FYI - Attached is a sediment removal plan Chemours submitted yesterday afternoon due to a slug of sediment
moving down the channel towards the 003 intake. Please see DEQ's response below.
Sergei, since this affects treatment and requires some additional sampling at and around Outfall 003 it may be
good to put the attached plan and DEQ's response on Laserfiche and the electronic NPDES permit file.
Thanks,
Julie
Julie A. Grzyb, Deputy Director
Division of Water Resources
1617 Mail Service Center, Raleigh, NC 27699-1617
919/707-9147 (wk); 336-210-8454 (cell))
From: Grzyb, Julie <[e-mail]>
Sent: Thursday, December 17, 2020 2:54 PM
To: Garon, Kevin P <[e-mail]>
Cc: Compton, Christel E <[e-mail]>; Bahr, Sebastian <SEBASTIAN.BAH [e-mail]>;
Chris Butler <[e-mail]>; Wojoski, Paul A <[e-mail]>; Greer, Emily C CIV USARMY
CESAW (USA) <[e-mail]>; Smith, Ronnie D CIV USARMY CESAW (USA)
<[e-mail]>; [e-mail] <[e-mail]>; Smith,
Danny <[e-mail]>; Holman, Sheila <[e-mail]>; Lane, Bill F <[e-mail]>
Subject: Re: [External] Chemours 003 Sediment Removal Work Plan
Kevin,
DEQ's response to Chemours plan:
On December 16, 2020, Chemours' contractor, Fayetteville Works (Geo Services LLC) provided an Outfall 003
Sediment Removal Workplan to DWR. This plan proposes the immediate implementation of Phase I sediment
removal plan upon DWR's e-mail approval. It is DWR's understanding that the purpose of this sediment
removal is to remove sediment that has aggraded in the stream channel that is at risk of interfering with WWTP
operations and thereby resulting in the discharge of contaminated wastewater into the Cape Fear River.
Under these extraordinary circumstances you have identified and because the Corps of Engineers is not
requiring an additional permit, no requirement for a 401 Certification is triggered. DEQ expects Chemours to

maintain compliance with its applicable NPDES permits, 401 Certifications and 15A NCAC 213 water quality
standards. Additionally, there shall be no disturbance to the original stream bed, bank and profile, and no
permanent structure(s) put into the channel. Lastly, daily influent and effluent sampling of turbidity should be
started at the treatment plant prior to sediment removal along with collecting an instream sample for PFAS
compounds midway through the removal process, upstream of the reservoir and downstream of the discharge
point (— in the middle of the channel). Please notify the Fayetteville Regional Office when sediment removal is
expected to start and the estimated duration time.
By copy of this email, DWR does not object to the removal of sediment as described in the Outfall 003
Sediment Removal Workplan, and as stipulated above.
DEQ requests that Chemours provide a written response, an after -action report, within 5-days of sediment
removal completion. Your response should address items 1-8 listed below:
1) On a map, clearly identify the number of linear feet depicting the footprint of the work impacted by this
disturbance, from the furthest downstream location to the most upstream extent of the removal effort.
2) Confirm that the work was conducted such that the original stream bed, bank and profile during your
efforts to remediate was not impacted.
3) Confirm no permanent structure or discharge of fill was placed into the stream channel.
4) Provide a written account estimating the volume of sediment that has been removed from the
stream. Also provide an account of the control measures used for temporary stabilization/ sediment
control while this work is under way, including what oversight maintenance that was required.
5) Please explain where and specifically how the sediment will be stored and managed going forward such
that runoff from the sediment will be prevented from flowing back into the stream or Cape Fear River
during future storm events.
6) Explain in your response when (dates) you anticipate having sediment characterization (data) for
PFAS/Metals for the subject dredged sediments.

7) Provide an account of how Chemours plans to ultimately dispose of the removed sediment/solids.
8) Finally, include a detailed account of the long-term proposal to protect the treatment system intake.
This response does not address or approve future scenarios and DEQ reserves the right to evaluate and
comment on any future plans Chemours proposes to remove sediment from the stream.
Thank you for your attention to this matter. Please do not hesitate to contact Paul Wojoski if you have any
questions.
Julie A. Grzyb, Deputy Director
Division of Water Resources
1617 Mail Service Center, Raleigh, NC 27699-1617
919/707-9147 (wk); 336-210-8454 (cell))
From: Garon, Kevin P <[e-mail]>
Sent: Wednesday, December 16, 2020 4:05 PM
To: [e-mail] <[e-mail]>; Smith, Ronnie D CIV USARMY CESAW (USA)
<[e-mail]>; Greer, Emily C CIV USARMY CESAW (USA) <[e-mail]>;
Wojoski, Paul A <[e-mail]>; Grzyb, Julie <[e-mail]>
Cc: Compton, Christel E <[e-mail]>; Bahr, Sebastian <SEBASTIAN.BAH [e-mail]>;
Chris Butler <[e-mail]>
Subject: [External] Chemours 003 Sediment Removal Work Plan
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All,
Please find attached our 2 phase plan to handle the sediment flow discussed this morning heading toward our 003
intake structure. Phase 1 would be immediate upon your e-mail approval. We would like to get into the field and start
removing this sediment front as early as tomorrow. Our understanding from the call this morning is that we will not
need a permit to perform Phase 1, but will need to modify the current permit before we can perform Phase 2.
Thanks, and I look forward to any comments on the plan. If you need additional information, let us know. As soon as
we hear back from both the Corp and DEQ we will begin Phase 1 removal.
Thanks,
Kevi n
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4M
GEOServioes, LLC, Geotechnical and Materials Engineers
Chemours Fayetteville Works — Outfall 003 Sediment Removal Workplan
1 Project Obiectives
Based on the current sediment loading at Outfall 003 sediment buildup is required to be removed prior
to reaching the intake structures for the wastewater treatment plant and minimize any potential
damage to the intake and treatment systems. The objective is to remove sediment that is not in
solution from the channel. This maintenance will minimize the amount of sediment migrating on the
channel bed and maintain the original design elevations. Figure 1 displays the project area and Figure 2
displays the current migration of the sediment.
WWTP Intake and Dam
Figure 1 — Project Area
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Figure 2—Sediment Migration
GEOServices, LLC 1 5559 North Lee Highway, Cleveland, TN 379311 Phone [phone] Fax [phone] www.geoserviceslic.com

Sediment Removal Workplan
Outfall 003 — Fayetteville, North Carolina
2 Proposed Corrective Action Plan
GEOServices Project No. 45-20400A
December 16, 2020
After field review of the sediment loading in the channel at Outfall 003, corrective activities are required
to protect the downstream infrastructure. GEOServices will implement long-term maintenance and
near -term corrective action. During the corrective action activities, some phases likely will be performed
simultaneously with others.
1. Phase I (Mechanical Removal of Sediment): Temporary access roadways are in the process of
being constructed on the project site to allow for sediment removal and to facilitate the
transportation of the sediment material to a stockpile location area. After completion of the
temporary access roads, a work area will be developed adjacent to the channel. Figure 3 below
documents the initial haul road to be utilized for the removal.
Figure 3 — Access Road
After installing temporary access adjacent to the channel, a long reach excavator will be utilized
to mechanically remove the excess sediment, see Figure 4 below. The sediment will be hauled
to a stockpile/dewatering area adjacent to the wastewater treatment plant outside of the 100-
year floodplain, see figure 5.
Figure 4 —Sediment Excavation Area
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Sediment Removal Workplan
Outfall 003 — Fayetteville, North Carolina
Figure 5 — Stockpile Area
GEOServices Project No. 45-20400A
December 16, 2020
The stockpile area will be graded to drain towards the creek to allow the water to drain to the
outfall channel. The water in the outfall channel will be captured by the wastewater treatment
plant intakes and treated prior to discharging downstream of the dam, through Outfall 003.
The stockpile area will be surrounded by a combination of silt fence and haybales. The floor of
the stockpile area will be lined with Visqueen plastic liner and graded to drain on the creek side.
Based on the required timely response and the uncertainty of the volume of sediment in the
channel, this activity may be required multiple times to capture the sediment that is accessible.
As an alternative for the immediate action Chemours is procuring materials and equipment to
address multiple clean outs prior to Phase II being permitted and constructed. The alternative
method includes the use of a hydraulic cutting head (See Figure 6) to remove the sediment and
transport directly to Geotube° (See Figure 7) for dewatering, where water will drain to the
upstream side of the dam and allow for treatment at the WWTP.
Figure 6 — Hydraulic Cutting Head
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Sediment Removal Workplan GEOServices Project No. 45-20400A
Outfall 003 — Fayetteville, North Carolina December 16, 2020
Figure 7 — Geotube° Dewatering System
2. Phase II (Long -Term Maintenance): Based on limited reach of the excavator in the channel, we
anticipate multiple maintenance activities will be required. To allow for future maintenance
activities and to enhance our ability to extend the reach of the excavator, we will be proposing
to build an access platform within the channel and installing a rock check dam to minimize the
amount of sediment that reaches the intakes. We anticipate the check dam to be
approximately 4 feet high and 24 feet in length, but the final determination will be based on the
information gathered during Phase I. Phase 11, the Long -Term Maintenance plan, will be
designed to minimize the amount of maintenance and sediment loss, but is the longer -term
solution although Phase I will dictate the final needs and schedule of Phase 11.
At this time, Phase I is the requested action and the permit and construction requirements will be
developed in the future for Phase II action.
3. Phase 1 Mechanical Sediment Removal
Standard excavation equipment will be used to remove the materials from the channel. A track -
mounted excavator will be used to remove the sediment and loaded into trucks for transport back to a
stockpile area adjacent to the wastewater treatment plant for proper storage until final disposal can be
determined.
Sediment Removal Activities
• Mobilizing equipment and personnel
• Construct temporary access to the area adjacent to the channel
• Completing minor improvements to the existing surface adjacent to the wastewater treatment
plant for a stockpile and dewatering area utilizing erosion and sediment control best
management practices
• Install silt curtains in the channel in the vicinity of the wastewater treatment plant intake
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Sediment Removal Workplan
Outfall 003 — Fayetteville, North Carolina
GEOServices Project No. 45-20400A
December 16, 2020
Begin mechanical excavation of the sediment
Characterization of sediment for disposal per the Soil and Materials Waste Management Plan.
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