20140957 Ver 2_Add Info - JAB Notes_20171016

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Dominion Energy Smvices, Inc.
5000 Dominion BouIevard
Glen Men. VA 2,3060
DominionEnergy.com
October 13, 2017
ELECTRONIC MAIL
Jeff Poupart
Water Quality Section
North Carolina Department of Environmental Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
Jeff.Poutl)[e-mail]
Re: Atlantic Coast Pipeline — DWR Project #14-0957 v2
Response to Request for Additional Information — Meeting FoHow-up
401 Water Quality Certification Review
Dear Mr. Poupart:
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;ft Dominior
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Atlantic Coast Pipeline, LLC (Atlantic) is providing the enclosed responses to the request for
additional information dated September 14, 2017, from the North Carolina Department of
Environmental Quality (NCDEQ) an Atlantic's Water Quality Certification application, which we
also discussed during a meeting with NCDEQ staff on September 29, 2017. The enclosed responses
are in addition to responses provided on September 22 and 29, 2017.
Each of the items requested by NCDEQ staff during the September 29, 2017 meeting are I isted
below, followed by a response or updated information from Atlantic.
NCDEQ requests site-specific drawings that illustrate plan views of a horizontal directional
drill and conventional bore (to also include a cross sectional view) crossing of Beaverdam.
Swamp and Raft Swamp.
Atlantic Response: Atlantic has provided drawings illustrating potential workspace layout and cross-
sectional drawings for Beaverdam Swamp and Raft Swamp, included in Attachment A. The
drawings illustrate the additional workspace that would be needed for a conventional bore and a
horizontal directional drill.
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The horizontal directional drill (FrDD) exhibit depicting alignment and workspace for Beaverdam
Swamp presents two potential HDD options. Both options include a horizontally straight route
between endpoints located adjacent to seasonally flooded wetlands. The waterbody known as
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Beaverdam Swamp is characterized as a 45 to 50 foot wide perennial waterbody with an estimated I t t"
depth of approximately 3 to 5 feet. The attached HDD alignment traversing Beaverdam S
ft,a:dJqccnt wetlands deviates from the pipeline route both filed with the Federal Energy Regulatory I'd
Commission 01� and used for right-of�way/easement acquisition, Therefore, this route was
developed based on the assumption that landowners would provide consent and FERC would approve
a variance for the proposed route adjustment associate with alignment.