SW6190507_ACP Add Info Request_20190621

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
NORTH CAROLINA
Environmental Quality
June 21, 2019
CERTIFIED MAIL
RETURN RECEIPT REQUESTED 7003 2260 0005 5380 9167
Leslie Hartz, Vice President of Engineering and Construction
Atlantic Coast Pipeline, LLC
c/o Dominion Energy Transmission, Inc.
707 East Main Street
Richmond, VA 23219
Subject: Request for Additional Information
Stormwater Permit No. SW6190507
ACP Pipe Yard PY 09-B
Harnett County
Dear Ms. Hartz:
The Division of Energy, Mineral and Land Resources (Division) received a Stormwater Management
Permit Application for the subject project on May 20, 2019. A preliminary review of the submitted
application package has determined that additional information is needed to meet the requirements of 15A
NCAC 02H A 000 and continue the stormwater permit application review.
Please note that the Division is allowed ninety (90) calendar days from the receipt of a completed
application to issue the permit. Failure to provide the requested additional information to DEMLR
by July 22, 2019 will result in the application being returned as incomplete. The return of a project
application necessitates resubmittal of all required items, including the application fee.
If additional time is needed to submit the requested additional information, then a request for extension
may be submitted to the Division for approval. The request must indicate the date by which the required
information is proposed to be submitted.
The submittal of the requested additional information listed below does not preclude additional requests
for information as necessary to determine compliance with regulatory requirements prior to permit
issuance. The requested additional information at this time is:
Cover Sheet (Sheet 1 of 9)
1. Denote site location on Soil Map.
2. Please remove sheets 8 and 9 as they are not relevant to the post -construction stormwater plan.
These two plan sheets are only applicable to the NCG010000 permit, which is separate from the
post -construction stornwater permit.
3. Recommend placing the Plan Reproduction Warning (information may be lost in copying and/or
gray scale plotting) on every sheet. The plans are insufficient for construction if not provided to
North Carolina Department of Environmental Quality I Division of Energy, Mineral and Land Resources
512 North Salisbury Street 1 1612 Mall Service Center I Raleigh, North Carolina 27699-1612
Wmto'
10A1010"''\ 919.707.9200

the contractor(s) in color, and individual plan sheets could potentially be distributed without the
cover sheet.
Overall Stormwater Site Plan (Sheet 2 of 99
It is expected that all approved Erosion and Sediment Control (ESC) Plan devices could require
maintenance or modification when the site transitions from the construction phase to the post -
construction (PC) phase. In some cases, different contractors may be involved in performing the
ESC and PC site work. Therefore, all PC device references must be specifically included in this
plan set. Items currently referenced to the ESC Plan that affect the post -construction
functionality of the site and should be included in this PC plan set include:
a. Discharge structure outlet protection detail
b. Eastern swale detail (including stabilization)
c. Middle swale detail (including stabilization)
2. Delete "proposed" from the eastern swale and middle Swale labels.
3. Label the wetland forebay and denote the forebay boundary. This is particularly important
because of the atypical forebay design.
4. The equalization pipe under the driveway entrance is noted on the plan sheet as a 12" diameter
CMP culvert. Section 4.8 of the Stormwater Management System Design document states that
this pipe was designed as a 24" RCP. Please correct the discrepancy.
5. Top of bean label lists elevation 194. The topo and design calculations show elevation 195.
Please correct the discrepancy.
6. It is not clear how the 0.70-acre topsoil segregation area that is bounded by the constructed
wetland, middle swale and eastern swale will be accessed, utilized and prevented from impacting
the constructed wetland device and the existing wetland during the post -construction phase of
development. Please clarify.
7. Include the turf reinforcement mat symbol in the legend.
8. Gravel Area symbol appears to denote the boundary of the gravel parking lot, not the actual
gravel area. Please clarify by either changing label to Gravel Area Boundary or including the
symbol throughout the gravel area.
9. Denote outlet structure location.
10. Revise Stormwater Wetland Detail label to include both details (Detail 1 Sheet 6 and Detail 3
Sheet 6).
11. Provide the required 10-foot wide access easement for maintenance [Ref. 15A NCAC 02H
.1050(8)].
Landscaping Plan Sheet 3 of 9
1. The listed cross -sections A/3 and B/3 are provided on Sheet 5 and should be denoted as A/5 and
B/5, respectively.
2. Denote the outlet structure.
3. Recommend a heavy border and a match line for section A -A to clearly denote the two separate
details shown on this page.
4. Please update legend to include:
a. Both shades of brown shown on the plan. Only one is listed.
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b. Turf Reinforcement Mat
c. Gravel Area
5. Notes No. 2 includes the three specific options provided in 15A NCAC 02H .1054(14). To avoid
indicating that the contractor can choose options other than those specified on the plans, please
revise to include only the appropriate option(s) for the specific planting plan on Sheet 4 [i.e. only
item 2(a)].
6. Specify non -clumping turf grass on embankments [Ref. 15A NCAC 02H .1055(15)].
7. Notes No. 5 states that plantings shall be installed several weeks prior to the first frost. This is
also noted on Sheet 4 of 9. However, these notes conflict with the Sheet 6 of 9, Construction
Specifications Notes No. 6 which states that the optimal planting period is early April to mid -
June. As provided in 15A NCAC 02H. 1054(13), it is generally safe to install wetland plants
from the average last spring frost to several weeks before average first fall frost. Please resolve
the discrepancy.
8. Notes No. 6 states, "Plant material, species, size, planting forms and locations subject to
change..." Per 15A NCAC 02H .1054(12), the landscape plan is required to be by an appropriate
professional. Therefore, changes to the approved plan cannot be enacted solely by the contractor
and will constitute a permit modification. Please clarify the requirements.
9. Notes No. 10 states that "The contractor shall obtain topsoil that is suitable for the proposed
wetland plants and provide the distributor's soil analysis results to the owner..." Per 15A NCAC
02H .1054(4), the pH, compaction and other attributes of the first 12-inch depth of the soil shall
be adjusted if necessary to promote plant establishment and growth. Include the general
parameter specification in the plans and change the word "proposed" to installed. It is
recommended that owner approval be required prior to placement of the soil, not just receipt of
the soils analysis.
Landscape Plan (Sheet 4 of 9)
i . Notes No. 2 includes all three temporary inundation zones options as provided in 15A NCAC
02H .1054(14). To avoid indicating that the contractor can choose other options, please revise to
include only the appropriate option for the specific temporary inundation zone planting plan (50
herbaceous per 200 sf (2-11 spacing)) or rely solely upon Planting Note No. 1 which specifies 2-
foot centers and is applicable to both shallow water zones and temporary inundation zones.
2. The Temporary Pool Elevation denoted in the legend does not show clearly on the color plan
sheet. Please clarify with a different line weight or symbol.
3. Notes No. 5 states that plantings shall be installed several weeks prior to the first frost. This is
also noted on Sheet 3 of 9. However, these notes conflict with the Sheet 6 of 9, Construction
Specifications Notes No. 6 which states that the optimal planting period is early April to mid -
June. As provided in 15A NCAC 02H .1054(13), it is generally safe to install wetland plants
from the average last spring frost to several weeks before average first fall frost. Please resolve
the discrepancy.
Constructed Wetland Cross Sections (Sheet 5 of 9)
1. Remove "proposed" from the legend items.
2. Label temporary and permanent pool elevations on Constructed Wetland Section B-B.
3. Because the forebay is atypical, it is recommended that that the equalization pipe and swale be
included on profile Section A -A.
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Stormwater Measures - Details (Sheet 6 of 9)
Construction Specifications No. 3 states that "...it maybe necessary to modify the planting plan
to reflect altered depths or the availability of wetland plant stock..." Per 15A NCAC 02H
.1054(12), the landscape plan is required to be by an appropriate professional. Therefore,
changes to the approved plan cannot be enacted solely by the contractor and approval of any
changes by an appropriate professional is required. Please clarify the requirements. Additionally,
an adjustable outlet device to correct construction errors/allow for lower ponding during first
growing season is recommended.
2. Stormwater Wetland Cross Section Detail 1:
a. Specify a valve for the riser dewatering method.
b. Dewatering method should include an elbow to create a submerged outlet.
c. Add outlet protection detail rather than referencing the ESC Plan. See Comment 1 under
Overall Stormwater Site Plan (Sheet 2 of 9) above.
d. Reference Detail 2 on Sheet 7 for emergency spillway stabilization.
e. Extend arrow for "3' x 2' NCDOT Drop Inlet" label to the box.
f. The riser outlet to establish the temporary pool is shown above the temporary inundation
zone elevation and does not have an elevation label. Confirm that the temporary pool
outlet is correctly shown and the outlet elevation is appropriately indicated.
g. Specify the anti -seep collar material.
3. Riser Structure, Detail 2: The riser outlet to establish the temporary pool is listed as elevation
193.5. This is the top of riser elevation. The temporary inundation zone elevation should be
noted as 192.9.
4. Wetland Specifications, Detail 3: The listed forebay depth is 24". However, the forebay depth
appears to be 2.4' (192.4 — 190). Please confirm the forebay depth.
5. Construction Specifications:
a. No. 2 — This item appears to be an ESC reference. All required stabilization should be
specified rather than referencing the agencies that can provide information on ESC
techniques.
b. No. 6 - Ensure this is consistent with Sheet 3 Note No. 5 and Sheet 4 Note No. 5.
6. Maintenance:
a. Note No. 2: It is not clear how the water level can be adjusted. An adjustable outlet
device to correct construction errors/allow for lower ponding during first growing season
is recommended. See also Comment 1 under Stormwater Measures - Details (Sheet 6 of
9) above.
b. It is unclear what direction the statement "(Refer to the NCDEQ Stormwater Design
Manual regarding stormwater wetlands for any design concerns)" is intended to convey
to the contractor. Contractors should not be authorized to alter the design or make
changes to the approved design. All design concerns should be addressed by the
approved plans or an appropriate licensed design professional. Please clarify.
Construction Sequence No. 2: It is unclear what direction this item is providing, "Excavate top of
the basin to El. 192 to remove any unwanted contaminates that may hinder wetland thriving
ability." It would appear that this refers to the ESC Plan and sediment basin as there are no
provisions for removing accumulated sediment prior to converting the sediment basin into the
wetland. Please clarify.
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Stormwater Measures - Details (Sheet 7 of 9)
1. Revise Detail 2 title to Turf Mat Reinforcement (Emerizengy Spillway) Detail.
Stormwater Management System Design Document
1. Section 4.8 calls for 24" RCP equalizer pipe. Plans show 12" CMP. Resolve discrepancy. See
also comment 4 under Overall Stormwater Site Plan (Sheet 2 of 9) above.
2. The request to place the emergency spillway in fill material as noted in Section 6 is acceptable.
3. Please denote what constitutes the upstream and downstream forebay in Table 3.
4. The pipe run length in Table 6 is listed as 33.5'. However, the standard laying length should be
30.5' as noted on the plan sheets. Resolve discrepancy.
Operation and Maintenance Agreement
The Operation and Maintenance Agreement information in some rows has been cut off. Please
reformat and reprint.
Please reference the State -assigned project number SW6190507 on all correspondence and submit to:
DEMLR Stormwater Permitting Program
Attn: Jeanette Powell
1612 Mail Service Center
Raleigh, NC 27699-1612
Be advised that the construction of any impervious surfaces prior to issuance of a post -construction
stormwater permit, other than a construction entrance under an approved Sedimentation Erosion Control
Plan, is a violation of NCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-
215.6A.
If you have any questions concerning this matter please feel free to contact Jeanette Powell at
Jeanette.Powell(wncdenr.gov or [phone].
Sincerely
S. Daniel Smith
Cc: Mr. Scott A Robinson, PE, ERM NC, Inc.
Spencer Trichell, Dominion Energy
Richard Gangle, Dominion Energy
DEMLR Fayetteville Regional Office
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