20090266 Ver 3_Modifications_20110125

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Transmittal Cover Sheet
5410 Trinity Road, Suite 320
Raleigh, North Carolina 27607
Tel: [phone]
Fax: [phone]
EA
To: Mr. Ian McMillan Date: 01/24/11 Transmittal No.: 1
512 N. Salisbury Street
h
h Project No.: 134891 Task No .: 400
Archdale Building - 9t
fl. And 6t
fl.
Raleigh, North Carolina 27604 Project Title: GUC Raw Water Intake Additional and CA
Services
From: Shearin Dramby Contrac t No.:
We are sending the following item(s): Sent via:
? Shop Drawings ? Prints ? E-Mail ? U.S. Mail
? Plans ? Samples ® Fed Ex ? Courier
? Change Order ? Specifications ? UPS ? Hand Carried
® Request for Permit Modification ? Overnight Express ?
These are transmitted as checked below:
? For approval ? For review and comment ? Issued for construction
® As requested ? Reviewed as noted ? Issued for bid
? For your use ? For reference only ?
If attachments are not as noted. please notifv sender at once.
No. of
Copies Revision Date
or No. Document or
Drawing No.
Description
5 01/24/2011 404/401 Request for Permit Modification hard copies
1 01/24/2011 404/401 Request for Permit Modification electronic copy (CD)
1 01/24/2011 Check for payment of $240.00 -;
Remarks:
JAN 2O
Mr. McMillan,
WIrs""?Y
As discussed, the GUC Raw Water Intake Impacts Map has been revised to include Tar Pamlico Riparian"'O4
Buffer and ordinary high water. A check for $240.00 is also attached for the requested permit modification.
Please contact me if you have any questions or concerns.
Thank you.
Ua
cc: Josh Pelletier, U.S. Army Corps of Engineers Prepared by: Tiffany Tirico
Title: Project Coordinator
5410 Trinity Road, Suite 320
Raleigh, North Carolina 27607
Tel: [phone]
Fax: [phone]
www,brownandcaldwell.com
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January 24, 2011
Mr. Josh Pelletier
U.S. Army Corps of Engineers
2407 West Fifth Street
Washington, NC 27889
Mr. Ian McMillan
512 N. Salisbury St.
Archdale Building - 9th floor and 6th floor
Raleigh, NC 27604
Subject: Greenville Utilities Commission
Request for Permit Modification
Section 404 Permit No. 2009-00541 & Section 401
Certification No. 09-0266 v 3
Dear Sirs:
As noted in the permit modification request dated December 22, 2010, GUC recently
completed construction of their new intake in the Tar River and the installation of a
sediment and scour management system for the existing intakes (Section 404 Permit #
2009-00541 and Section 401 Water Quality Certification #09-0266). Upon completion
of construction, the contractor restored the site in October 2010 according to the
approved final grading, planting, and buffer re-establishment plans.
Flooding and associated high river velocities occurred in the region in October 2010 and
caused significant erosion of the river bank in the area of the new intakes, resulting in
undercutting and sloughing of approximately 120 linear feet of the restored riverbank.
The causes of the erosion stem from excessive high water events along with the distur-
bance associated with the removal of the coffer dam and the backfilling of the pipe
trench. Erosion on the riverbank is currently minor to moderate, but is not currently
active. Further erosion would likely occur during high water events and could potentially
cause an increase in sedimentation around the intakes. This area is in need of repair in
order to fulfill the riverbank restoration plan and protect the pipe infrastructure. The
remaining length of the restored riverbank in the project area is stable and not expe-
riencing erosion. A bathymetric and topographic survey was performed on the affected
area to verify the extents of the riverbed erosion and to develop a stabilization plan.
In order to stabilize the riverbank, placement of 3-foot diameter boulders is proposed
from elevation -6 MSL to approximately elevation 2 MSL (OHW) as shown on the at-
tached graphic. The boulders will provide a more permanent foundation for the river-
bank and will allow the riverbank to re-stabilize. This stabilization measure will require
120 linear feet (0.06 acres) of permanent impacts to the Tar River. The area of impact
is within the boundaries of the current permit. Permanent buffer impacts are not
proposed for this project. Access will be provided within an existing access road shown
on the attached graphic.
P:\Greenville Utilities\134891 Raw Water Intake\-400 Pennitting\-300 401-404 Wetlands Permits\12_2010 Permit Modification Bank
Stabilization\FINAL Permit Modv2.Doox
January 24, 2011
Page 2
The engineer evaluated replacing the bank with compacted native soil, but this method
would require placement of a cofferdam to work in the dry in order to allow proper
compaction of the riverbed material. The vibrations from installing a cofferdam around
the new intake pipes could be harmful to aquatic species and could jeopardize the
integrity of the new pipe, fittings and pipe foundation. Installation of a coffer dam could
also cause further erosion of the riverbank in this area and cause another scour hole
similar to the hole experienced with the previous coffer dam. The only identified,
practicable alternative to stabilize the Tar River bank in this area is to place the pro-
posed boulders as shown on the attached figure.
Completion of this work is required during a two-week window within the February 15 -
June 30, 2011 in-river construction moratorium. If GUC delays performing the work
after the in-river moratorium, further bank de-stabilization and erosion will likely occur
requiring additional permanent impacts beyond what is currently requested. Additionally,
it should be noted that although a two-week construction window within the moratorium
is requested, actual in-water work could only take up to 4 days to complete. Stabiliza-
tion is proposed to be performed from the top of bank by individually placing each
boulder from elevation -6 MSL to approximately elevation 2 MSL. This will help protect
the new intake screen, reduce disturbance of the riverbed, and allow for better place-
ment of the boulders to stabilize the riverbank. Appropriate erosion and sediment
control measures will be implemented to prevent sediment from leaving the stabilization
area and entering the Tar River.
We are requesting a modification to the existing permits (Section 404 Permit # 2009-
00541 and Section 401 Water Quality Certification #09-0266) for the proposed bank
stabilization activities. Upon authorization, we anticipate 30 days to mobilize equipment
and an additional two weeks to complete the work, weather permitting. Please contact
me should you have any questions or required additional information.
Very truly yours,
J. Shearin Dramby
Regulatory Specialist
cc: Mr. David Lekson, USACE - Washington, NC
Mr. Ricky Langley, GUC
Mr. David Springer, GUC
P:\Greenville Utilities\134891 Raw Water Intake\-400 Perinitting\-300 401.404 Wetlands Perinits\12 2010 Permit Modification Bank
Stabilization\FINAL Permit Modv2,Docx
IMPACTS TABLE
STREAM IMPACTS = 120 L.F. p
0.06 AC.
290 C.Y.
LEGEND:
PROPOSED RIPRAP

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HORIZONTAL SCALE: 1"=1d
SCALE: 110'
VERTICAL SCALE: 15
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C NUMBER
NUMBER
134581
Environmental Engineering and Consulting
5710TMityRoad
Suit9320
Palisades ll
NC27607(919)233-9178
Raleigh DESIGNED: BNASH CLIENT PROJECT NUMBER
,
,
,
, IMPACTS MAP
DRAWN: BNASH Utilities DRAWING NUMBER

SUBMITTED: DATE: CHECKED:
COMMISSION
FIGURE 1
POST OFFICE
POST 0FFICEICE BOX 1847 1847
CHECKED:
S APPROVED: DATE: APPROVED: GREENVILLE, NORTH CAROLINA 27835 SHEET NUABFR
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