WQ0000020_Corrective Action Plan_20200306

DUKE
ENERGY
March 6, 2020
Mr. Brett Laverty
North Carolina Department of Environmental Quality
Asheville Regional Office
2090 US 70 Highway
Swannanoa, NC 28778
410 S. Wilmington Street
Raleigh, NC 27601
Mailing Address
Mail Code NC 15
Raleigh, NC 27601
919-546-7863
Subject: Response to North Carolina Department of Environmental Quality Site Assessment
Review letter dated August 12, 2019 — Asheville Airport Area 1 Structural Fill
Dear Mr. Laverty:
Duke Energy is in receipt of the above -referenced letter from the North Carolina Department of
Environmental Quality (NCDEQ), which requested that a permanent cap system be developed to "abate
the infiltration of groundwater and/or precipitation into Area 1" and "to abate or control the.... seepage
water." Duke Energy partnered with Geosyntec Consultants of NC, P.C. (Geosyntec) to prepare the
enclosed Design Report - Permanent Cap System for Area 1 structural fill (Area 1). The proposed
permanent cap system will:
Abate or control seepage from Area 1 through the installation of a permanent cap system to
reduce and abate infiltration from precipitation into the CCR, which will lower the interstitial
water elevation over time;
• Achieve long-term slop stability factors of safety equal to or above 1.5; and
• Improve and actively manage stormwater runoff volume from Area 1.
Upon NCDEQ concurrence with this proposed cap system, Duke Energy will work with the Greater
Asheville Regional Airport Authority to obtain required access to the property and install the permanent
cap system. Note that the Greater Asheville Regional Airport Authority has conveyed that they are not in
agreement with the cap design through a February 24, 2020 letter to Duke Energy; that letter and Duke
Energy's response are also attached. If you have any questions or need any clarification regarding the
information provided, feel free to contact me at [e-mail] or at 919-546-7863 at
your convenience.
Res ullyRPE.i'
ted,
J n Toepfe
Lead Engineer, Duke Energy EHS CCP
Waste & Groundwater Programs
cc: Ms. Jessica Bednarcik —Duke Energy
Mr. Michael Reisman — Greater Asheville Regional Airport Authority
Mr. James McNash — Geosyntec

March 6, 2020
Mr. Laverty Letter
enc: Design Report Permanent Cap System, Asheville Regional Airport — Area 1 Structural Fill, Rev. 0,
Geosyntec Consultants of NC, P.C., March 2020
Greater Asheville Regional Airport Authority letter, February 24, 2020
Duke Energy response to Greater Asheville Regional Airport Authority, March 5, 2020

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R E G I Oeville NAL AIRPORT
Take the easy way out.
February 24th, 2020
Duke Energy
Mr. William M. Harrison, P.E.
CCP Engineering — Mgr Programmatic Engineering
400 S. Tryon Street
Charlotte, NC 28202
RE: Response to Duke Energy Letter Dated February 15th, 2020
Dear Mr. Harrison:
We are in receipt of your letter noted above which was in response to the Greater
Asheville Regional Airport Authority's (GARAA's) comments on the most current
proposed plans for Area 1. The following information and details are provided in
response to your letter.
It is important to reiterate that the intent of the airport in permitting CCB material
to be placed in any location on the airport, including Area 1, was specifically to
improve those areas in order to permit new aeronautical and non -aeronautical
development. Without the creation of land for future development, there was no
purpose in the airport accepting the placement of this material on its property.
2. The initial project which took place during the 2006-2009 timeframe transformed
approximately 14 acres of land for development. As a result of more recent
issues of course with the stability of the Area 1 slope, the NCDEQ has mandated
permanent improvements to this area.
3. Duke Energy presented its preliminary plans to GARAA on November 1st, 2018,
through a meeting between Duke Energy and Airport staff. At that time, the
stated intent was for Duke Energy to strip a certain amount of topsoil from Area
1, install a cap liner system, and then replace the top soil. GARAA staff were
generally in agreement with this plan, as it maintained the airports ability to
develop this acreage in the future without significant additional site
improvements, based on our understanding that the finished grade would be
generally level, while accounting for proper surface runoff.
4. There was no further communication from Duke Energy on this matter until
October 18th, 2019, when Duke Energy met with airport staff. No new
information was provided concerning design at this meeting, but rather it was an
opportunity for new personnel involved with the project for Duke Energy to meet
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