20180307 Ver 2_ResponseToChristyn_20180207

Reference No. 11123681
North Carolina #!vision OT
401 & Buffer Permitting Unit
Attn: Ms. Christyn Fertenbaugh
512 N. Salisbury Street, Rm. 925S
Raleigh, NC 27604
Dear Ms. Fertenbaugh'.
Be: Stevens Creek Trunk Sewer Phase 1 — Variance Application: Request for Additional
Information
EroLect Nam Stevens Creek Trunk Sewer
Coordinates: a - - roximately 1135-146 -80.65"
GHD Job Number 11123681
Charlotte Water Pro ect Number . 2017000405
i
In response to your email dated Friday, January 19, 2018, we have compiled a list of responses and
documents requested to complete the review process. On behalf of Charlotte Water, GHD requests your
approval for the construction of a sanitary sewer along Stevens Creek and Stevens Creek Tributary, and
within the Goose Creek Basin, utilizing PVC, AWWA 0900, Pressure Class 165 psi, DR25 as an equal to
ductile iron pipe. There have been no changes in request from the submittal on December 8, 2017 and
that includes the use of ductile iron pipe for all stream crossings and for pipe cover depths of greater than
20 --feet as shown on plans.
Included with the enclosed variance application, you will find plans, details, and specifications for the
proposed project.
GHD appreciates your assistance with this project. Please contact me at [phone] or
Jason. Mars,[e-mail] if you have any questions or require additional information.
Sincerely,
GHD,
Jaso Marshall, PE
Project Coordinator
Encl. Plans
Specifications
cc: Nicole Bartlett, Charlotte Water
Tony Martin, Charlotte Water
Chuck Bliss, Charlotte Water
Michael Bisignani, GHD
1609001
GHD
222 South Church Street Suite 400 Charlotte North Carolina 28202 USA
T7()4 342 4910 F 704 342 4911 w wvvw.ghdxarn

Lindsay Matthy, GHD
Response to General Comments:
DEQ Comment: As the entirety of this project is shown to be constructed within the 200 -foot buffer
as required by 15A NCAC 0213, and multiple areas constructed within the 50 -foot buffer, please
provide clarification as to what design alternatives were considered to potentially avoid these
impacts. Please also provide more information about how the project construction/materials as
depicted on the provided plans shall meet the requirements of 15A ICAC 02T.0105(n); and
specifically, how they shall provide equal or better protection of the environment in this area.
GHD Response: Alternatives outside of the 200 ft buffer zone were evaluated but deemed
unfeasible to locate a gravity trunk sewer The trunk sewer project matches the project limits for
the Stevens Creek Stream Restoration project being completed by Mecklenburg County
Stormwater and Stantec. GHD and Charlotte Water have been working with the stream
restoration team to design and construct the proposed alignment with the Stevens Creek and its
Tributary stream restoration in order to minimize overall project disturbance. Both of these
projects will be bid together and constructed along the same timeline. This will ultimately reduce
clearing and minimize disturbance to the overall area. Additionally the alignment was chosen with
input from NODE Q's Mooresville office and the project team has held several field meetings and
walks with Alan Johnson of NCDEQ for input on the location and disturbance to limit the overall
disruption to all stakeholders. Meetings and field visits have also been completed with USACE
and US Fish and Wildlife.
For requirements of 15A CAC 02T 0 1 05(n),
(1) equal or better treatment of the waste-, - P,VC pipe material provides an equal level of service
for the conveyance of wastewater.
(2) equal or better protection of the waters of the state; and — PVC pipe material produced under
A WWA and ASTIR standards is considered an equal to ductile iron pipe produced under similar
standards for water and sewer service. Gaskets materials are the same or similar in design and
function to provide equal protection for a leak free system. All pipe, no matter the material must
pass a zero leakage test to ensure a watertight system. PVC also has the advantage of being
inert to corrosion caused by hydrogen sulfide gas. Charlotte Water has experienced corrosion
issues with DIP and prefers to utilize PVC for its inert properties, Utilizing PVC eliminates the
need for corrosion protection required for DIP sewers providing equal or better protection against
leaks and pollution caused by corrosion.
(3) no increased potential for nuisance conditions from noise, odor or vermin. — Pipe material does
not affect environmental conditions.
2. DEQ Comment: It appears that the alignment of the buffers as shown on the plans (30-, 50-, and
200 -feet) is based on a proposed stream alignment, not the existing alignment. Please provide
more information regarding the proposed realignment of the stream, as this affects the buffer
zones through which this project is proposed to be constructed,
GHD Response: In prior discussions with Alan Johnson from NC DEQ and Mecklenburg County
Stormwater, it was determined that utilizing the 50 and 30 foot buffers reflecting the proposed
stream restoration alignment was most appropriate, As both projects will be constructed at the
same time, the 30 and 50 foot buffers for the proposed stream alignment are most reflective of
conditions at the time of post construction. Additionally, in most cases, the proposed stream
EMC Variance Response Letter - 02 7.2018

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alignment buffers pushes the proposed sewer alignment further from the existing stream top Of
bank.
a. DEQ Comment: it also appears that the 100 -year flood elevation lines are based on the existing
creek alignment rather than the proposed alignment. Please provide more information, as this
affects the installation of different manhole -types, per 15A NCAC 02T.0305(e),
GHD Response: We are awaiting final base flood models revision reflective of the 100 -year flood
elevation for the proposed stream restoration. We are aware of the requirements for either
minimum two feet rim elevations above the 100 -year flood line, or watertight lids and vents, We
have requested the revised floodplain mapping currently in process for a Conditional Letter of Map
Revision and wit] make changes to update manhole types, elevations, and vents as necessary to
comply with 15A N CA C 02 T, 0305(e).
3. DEQ Comment: As this project requests the usage of PVC in most locations whereas both the
02T and 026 rules require ductile iron within such a buffer, please provide clarification as to why
ductile iron cannot be utilized for this project.
GHD Response: We are requesting that PVC be considered as an equal to ductile iron pipe as
PVC is preferred to DIP due to its inert corrosion resistant properties. Ductile iron pipe requires
special coatings for sewer service and is susceptible to corrosion once liner has deteriorated,
4. DEQ Comment: The provided VAR 10-2013 form indicates that sewer lines located in wetland
areas shall have anti -seep collars installed, however, it was not clear where wetland areas are
impacted nor where anti -seep collars may be installed. Please clarify,
GHD Response: Plans will be updated accordingly to show the anti -seep collars. Where the sewer
alignment passes through wetland areas, we have callouts specifying to reduce clearing to 40 feet
width in the permanent easement. 'Wetiands are located on sheets 6, 7, and 12 and anti -seep
collars have been added to the drawings.
Plans/Sp ecif icatio n s:
t. DEQ Comment: All plans and specifications submitted for the variance must be signed/sealed
by a Professional Engineer licensed to practice in North Carolina, Please revise.
GHD Response: Plans and Specifications have been signed and sealed included in this
submittal.
2. Brief sections of specifications were provided. Please clarify if these are parts of Charlotte
Water's standard specifications, which are referenced by the provided plan sheets. All
specifications to be referenced by this variance that are not part of Charlotte Water's standard
specifications must be signed/sealed by a Professional Engineer licensed to practice in North
Carolina.
GHD Response: Technical specifications were provided specific to Stevens Creek Sanitary
Trunk Sewer project that incorporate Charlotte Water's standards for materials and
construction. Full project specifications have been Signed and Sealed for review.
3. DEQ Comment: Have the quality testing methods for gravity lines outlined in the provided
specifications been approved by the Public Water Supply Section — Plan Review Group as being
equivalent to water main standards as found in 15A NCAC 18C, per 15A NCAC 02T.0305(g)(5)2
if so, please provide a copy of the letter or email approving the testing methods. If this has not yet
been verified, please contact the Plan Review Team Leader Shashi Bhatta at
Shashi. [e-mail],
EMC VadanCe Response Letter - 02 7.2018

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,GHD Response: GHD is working with Sashi Bhatta for a resolution and will provide a formal
response at a later date.
4. DEQ Comment: It appears that multiple manholes depicted as being located within the current
I00 -year flood elevation are listed as having vented covers (e.g. H-17, 19, 20, 24, 25), All
manholes located within the 100 -year flood elevation must have a watertight seal, per 15A NCAC
02T.0305(e). Please revise such that all manholes located within the 100 -year flood elevation are
depicted as having watertight covers and frames, and ensure that the manhole schedule located
on plan sheet 2 correctly reflects which type of manhole cover shall be installed,
GHD Response: See previous response and general comments 2.a. Manholes with vented cover
located inside the 1007year floodplain have rim elevations well above (at least 2 feet) 100 -year
floodplain elevations. All manholes are pending further revisions pending flood study analysis.
Please note General Comment #2, as it appears that in many locations, the location of the
100 -year flood elevation may change significantly if the stream is realigned as shown on the
plans.
See previous response and general comments 2.a.
5. DEQ Comment: On plan sheets 9 and 11, a temporary stream crossing is depicted. Please clarify
if these tributary streams shall permanently cross the sanitary sewer after construction is
completed, and if so, please revise such that these sections of sewer are constructed of DIP as
the provided VAR 10-2013 form for variance requests to the 15A NCAC 02B rules indicates that
ductile iron shall be used for all stream crossings.
GHD Response: These intermittent tributaries crossings have been revised to include DIP at the
crossings. Please see plans included in this submittal.
6. DEQ Comment: On plan sheet 14, the distance between MH -28 and MH -29 appears to be greater
than 425 linear feet (measured at approximately 465 linear feet). Per 15A NCAC 02T.0305(i)(2),
please provide documentation from Charlotte Water indicating that they have the capability to
provide routine cleaning and maintenance on the sewer at the specified manhole separation,
GHD Response, - Charlotte Water has the capabilities to clean sewers beyond 500' and we have
verified with their Operations and Maintenance staff. Please see email communication between
Charlotte Water, Project Manager, Tony Martin and operations staff Lee William, See enclosures.
EMC; Variance Response Letter -02.7.2098