Mayo Gypsum Pad Assessment Comments Letter_20190614

ROY COOPER
Governor
MICHAEL S. REGAN
secretary
LINDA CULPEPPER
Director
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental Quality
June 14, 2019
Subject: Mayo Steam Electric Plant — Gypsum Pad Groundwater Assessment Plan
Comments
Dear Mr. Draovitch:
On May 15, 2019, the North Carolina Department of Environmental Quality Division of Water
Resources (Division) received the proposed Groundwater Assessment Plan for the Gypsum Pad at
the Mayo Steam Electric Plant. The Division has reviewed and hereby approves the proposed
assessment activities under the condition that the following item are addressed as part of the plan
implementation and the results reported in the comprehensive site assessment for the subject area
if the gypsum pad is confirmed to be positioned in a separate flow regime than ash basin area.
Otherwise, the results should be incorporated into facility's Corrective Action Plan (CAP) that
includes the impoundment.
• If the physical well locations of the proposed monitoring wells deviate by more than one
hundred (100) feet from the original proposed locations, please contact the Raleigh
Regional Office prior to boring/well installation.
• Include a map showing the extent of any liner beneath the gypsum pad.
The results should also be incorporated into the CAP's geochemical and groundwater fate and
transport models if the subject area is found to be coincident with the impoundment. If the results
of the modeling show current or future impacts to groundwater and/or surface water from this area,
then appropriate remedial strategies shall be proposed in the CAP.
North Carolina Department of Environmental Quality I Division of Water Resources
D_E �� 512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919.707.9000

If you have any questions, please contact Eric Rice (Raleigh Regional Office) at [phone]
or Steve Lanter (Central Office) at [phone].
Sincerely,
;onsg ard, Chief
Animal Feeding Operations and Groundwater Section
cc: RRO WQROS Regional Office
WQROS Central File Copy