NC0001422_Sutton BOD Comments Letter FINAL_20161221

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Water Resources
ENVIRONMENTAL QUALITY
December 21, 2016
Ed Sullivan
Duke Energy
526 South Church Street
Mail Code EC13K
Charlotte, North Carolina 28202
Subject: Basis of Design Report Comments
L. V. Sutton Energy Complex
Dear Mr. Sullivan:
PAT MCCRORY
(ioremor
DONALD R. VAN DER VAART
Secretary
S. JAY ZIMMERMAN
Dlrec•(or
On November 22, 2016, the North Carolina Department of Environmental Quality's Division of
Water Resources (Division) received the Interim Action Plan -Basis of Design (BOD) Report for
the L.V. Sutton Energy Complex. Division staff from the Wilmington Regional Office have
reviewed the BOD Report and offer the following comments:
The proposed approach presented in the BOD Report, including the supporting aquifer testing
results, groundwater modeling, and extraction well system design is sufficient to support
development of a final plan that will facilitate implementation of the proposed interim action at
the subject facility. Specific comments are provided below:
• Details regarding the groundwater fate and transport models and the groundwater
extraction system operation sections are needed to complete the 100% BOD Report.
A detailed plan for the effectiveness monitoring of the groundwater extraction system is
needed as part of the System Performance Metrics subsection. This monitoring plan should
include evaluation of the upper Peedee aquifer. If monitoring and ongoing site assessment
activities indicate impacts from the ash basins to the upper Peedee aquifer, modifications
to the groundwater extraction system maybe necessary.
An annual interim action system effectiveness monitoring Report shall be required to
document effectiveness of the groundwater extraction system. This Report shall provide
details concerning hydraulic data that includes cones of depression and hydraulic
capture. In addition, sampling and analysis results that support the interim action must be
documented. The annual effectiveness monitoring Reports shall include figures, tables,
cross-sections, maps, and time -series plots in a manner that addresses performance
metrics in integrated, comprehensive interpretation of site conditions related to the
State ofNorth Caroline � Endvonmenhl Quality � Water Resources
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919 707 9000

interim action. Reports submitted in a data summary format will not be approved as an
acceptable documentation of the monitoring program. The annual effectiveness
monitoring plan Report for each calendaz yeaz shall be submitted by Apri130�h of the
following yeaz.
• As part of the annual effectiveness monitoring Reports, predictive simulations shall be
made with the existing groundwater -flow model with extraction data. The fate and
transport models and geochemical models shall be re-evaluated based on data collected
regarding the constituent trends, aquifer response, pumping rates, capture zones, etc.
• The 100% BOD Report should include licensed engineer's certification and seal.
If you have any questions, please feel free to contact the Wilmington Regional Office at (910) 796-
7215 or Steve Lanter at [phone].
Sincerely,
S. JC < ay -Zimmerman, P.G., Director
Division of Water Resources
cc: Jim Gregson — WIRO Regional Office Supervisor
WQROS Central File Copy