20051216 Ver 3_Complaint Investigation_20160922

FINAL REPORT
SLOPE FAILURE REPAIR AND
SEDIMENT REMOVAL
EAST YANCEY WATER AND SEWER DISTRICT
YANCEY COUNTY, NORTH CAROLINA
EMCGM
A S S 0 C. I A T E S
CONSULTING ENGINEERS
BOONE, NORTH CAROLINA
Env i r a n m ental • P l a n n i n g & F i n a n c e
McGill Associates, P.A. • 468 New Markel Blvd. Ste. B, Boone, North Carolina 28607
Q,fice: [phone] • Fax: [phone]

FINAL REPORT
SLOPE FAILURE REPAIR AND
SEDIMENT REMOVAL
EAST YANCEY WATER AND SEWER DISTRICT
YANCEY COUNTY, NORTH CAROLINA
McGM
A S S O C I A T E S
468 New Market Boulevard, Suite B
Boone, North Carolina 28607
828-386-1920
Firm License No.: C-0459
SEPTEMBER, 2016
PROJECT NO. 12.00404

@McGill
September 22, 2016
US Army Corps of Engineers
Asheville Regulatory Field Office
151 Patton Ave., Room 208
Asheville, NC 28801-5006
Attn: Scott Jones
RE: East Yancey Water & Sewer District WWTP
Final Report - Slope Failure Repair and
Sediment Removal
Yancey County, North Carolina
Dear Mr. Jones:
McGill Associates, P.A. has completed the inspection of the slope failure repair
and sediment removal as was approved in the Corrective Action Plan East Yancey Water
and Sewer District submitted by McGill Associates, P.A. in July 2016. The Corrective
Action Plan was in response to the bank erosion and sediment loss into the South Toe
River at the East Yancey Water and Sewer District Wastewater Treatment Plant. This
report covers the corrective measures that were implemented to remove sediment from
the spill location and re-establishment of the eroded river bank and uphill slope.
This report represents the professional judgment and opinion of McGill Associates,
P.A. If there are any questions regarding this Final Report, please contact the undersigned
at your convenience. We appreciate your assistance in working toward full resolution of
this matter.
Sincerely,
J/
C. ��
Vilas
McGill Associates, P.A.
Program Services Manager- Environmental
Cc: Bryan Tompkins, US Fish and Wildlife Service
Byron Hamstead, US Fish and Wildlife Service
Andrew Moore, NCDWR
Nathan Bennett, Yancey County Manager
Mike Waresak, PE, Project Engineer
McGill Associates, P.A. Project # 12.00404
Environmental 0 Planning 0 Finance
McGill Associates, P.A. • 468 New Market Blvd. Ste. B, Boone. North Carolina 28607
O(Jice [phone] • Far (8 28) 386-1923

TABLE OF CONTENTS
1.0 INTRODUCTION............................................................................................ 1
2.0 SEDIMENT REMOVAL AND BANK STABILIZATION .................................. 2
3.0 TURBIDITY MONITORING............................................................................ 3
ATTACHMENTS
1). PHOTO SHEET 1
2). PHOTO SHEET 2
3). PHOTO SHEET 3
East Yancey Water and Sewer District Final Report
Slope Failure repair and Bank Stabilization McGill Associates, P.A.
Yancey County, North Carolina September 2016
12.00404 Page i

1.0 INTRODUCTION
The East Yancey Water and Sewer District WWTP project consists of the design
and construction of a wastewater treatment plant along the South Toe River in
Yancey County, NC near Micaville, NC.
The United States Fish and Wildlife Service received complaints of sediment
discharges into the South Toe River related to this project. A site visit revealed that
a large sediment deposit (approximately 20'x45') had formed in the river directly
across from the constructed wastewater treatment plant. This sediment deposit
was found to be approximately 24" at its deepest point before tapering to 0" at its
edges.
A site visit was conducted by McGill Associates, P.A. to find the source of this
sediment deposit on 7/18/16. It was concluded that during recent maintenance at
the wastewater treatment plant a large amount of clean water was discharged into
the river. This water washed out the toe of a constructed bank and carried sediment
into the South Toe River.
A meeting was held with the USFWS, NC DEQ, and USACE to determine the best
course of action to remove the sediment from the South Toe River. As a result of
this meeting the Corrective Action Plan - East Yancey Water and Sewer District
was submitted by McGill Associates, P.A. and was approved in July 2016.
East Yancey Water and Sewer District Final Report
Slope Failure Repair and Bank Stabilization McGill Associates, P.A.
Yancey County, North Carolina September 2016
12.00404 Page 1

2.0 SEDIMENT REMOVAL AND BANK STABILIZATION
Work began July 28, 2016 to remove the sediment deposit in the South Toe
River and begin re-establishing the eroded slope. A coir wattle coffer dam was
secured into the riverbed surrounding the in -stream work zone with wooden stakes
to prevent downriver sedimentation (see Photo Sheet 1). Once the coffer dam was
installed grading work began with a small excavator to remove the sediment
deposit. The excavator removed excess sediment down to natural river bed while
avoiding disturbance to the natural river bed substrate. The excavator only
operated within the area protected by the coffer dam and did not disturb existing
Oak and Green Ash trees adjacent to the work area (see Photo Sheet 1).
The removed sediment was placed in a temporary dewatering zone within
the work area until dry and then used to fill the eroded gully below the slope
failures. This area was returned as close as possible to original grade and
contours. The constructed slope was re -graded and compacted as necessary and
stabilized using suitable off-site fill material, as defined in the Corrective Action
Plan. The material was free of woody debris and large stones, and was suitable to
support vegetative growth. Fill was added until the eroded area matched existing
bank slopes (see Photo Sheet 1).
All disturbed areas were stabilized using erosion control matting, standard
erosion control seed mix, and native riparian seed mix. Once the regraded slope
was stabilized, the coir wattle coffer dam was removed from the river bed. The coir
wattles were then staked in to the repaired river bank and constructed slope area
to aid with erosion control and stabilization (see Photo Sheet 2). Bareroot woody
vegetation will be installed from the toe of slope to river bank during the planting
season, fall of 2016. A follow-up inspection will be performed by McGill Associates,
P.A. to ensure that the bareroot plantings were installed and established, and that
there are no further erosion issues at the site.
A site inspection performed by McGill Associates, P.A. on August 25, 2016
confirmed that the seed mix had begun to germinate and that grass cover was
beginning to establish within the disturbed area. There were no signs of erosion or
bank failure at the time of this inspection (see Photo Sheet 3).
East Yancey Water and Sewer District Final Report
Slope Failure Repair and Bank Stabilization McGill Associates, P.A.
Yancey County, North Carolina September 2016
12.00404 Page 2

3.0
DATA COLLECTION & FINDINGS
TURBIDITY MONITORING
Turbidity monitoring was performed approximately every two hours during
construction to ensure that downstream turbidity did not exceed the 10 NTU limit
for designated trout waters or background levels taken from readings directly
upstream of the project site, whichever was greater. Samples were taken
approximately 50 -feet upriver, adjacent to, and 50 -feet down river form the work
area before and during construction activities on July 28, 2016. Turbidity readings
did not exceed the 10 NTU limit for designated trout waters during construction
activities.
LaMotte 2020 Turbidimeter Readings — Nephelometric Turbidity Unit (NTU):
Up River (50 -feet)
9:00 AM — 4.64 NTU
Begin Sediment Removal
11:00 AM — 4.38 NTU
1:00 PM — 3.84 NTU
3:00 PM - 4.03 NTU
Adjacent to Work Area
9:00 AM — 5.15 NTU
Begin Sediment Removal
11:00 AM — 5.91 NTU
1:00 PM — 6.43 NTU
3:00 PM - 6.55 NTU
Down River — (50 -feet)
�g1I�1101I1111111111111111
Begin Sediment Removal
11:00 AM — 5.12 NTU
1:00 PM — 6.29 NTU
3:00 PM - 6.89 NTU
East Yancey Water and Sewer District Final Report
Slope Failure Repair and Bank Stabilization McGill Associates, P.A.
Yancey County, North Carolina September 2016
12.00404 Page 3

■
y
• V
Photo One: View looking southwest at sediment
Photo Two: View looking southwest at sediment
deposit in the South Toe River.
removal operation with coir wattle coffer dam
installed and staked into riverbed to control
turbidity.
� Y
_ F
I
Photo Four: View looking west at sediment
Photo Three: View looking west at coir wattle
coffer dam during sediment removal.
removal area. Sediment has been pulled from the
riverbed and shaped to original contours along
river bank.
SEDIMENT REMOVAL AND
McGM
PHOTO SHEET 1
PROJECT #
BANK STABILIZATION
AUGUST 9, 2016
12.00404
ASSOCIATES
ENVIRONMENTAL ■ FINANCE
YANCEY COUNTY, NORTH CAROLINA
468 NEW MARKET BLVD. STE B BOONE, NC 28607 PH. [phone]

_
Photo Four: View looking east toward the South
Photo Five: View looking east At the South Toe
Toe River at the eroded slope and river bank area.
River at area where sediment was removed from
Sediment has been removed from the river bed and
the river bed. Natural river bed substrate can be
the river bank re -sloped and seeded. Matting and
seen at toe of slope.
coir wattles have been staked in to control any
erosion before the slope is permanently vegetated.
Photo Six: View looking southwest toward the
Photo Seven: View looking west at area where
eroded slope and river bank area. Matting has been
sediment was removed from the river bed.
staked into the toe of the bank to control any erosion
Natural river bed substrate can be seen at the
before the slope is permanently vegetated.
river bank and at bottom of photo.
SEDIMENT REMOVAL AND
McGM
PHOTO SHEET 2
PROJECT #
BANK STABILIZATION
AUGUST 9, 2016
12.00404
ASSOCIATES
ENVIRONMENTAL • FINANCE
YANCEY COUNTY, NORTH CAROLINA
468 NEW MARKET BLVD. STE B BOONE, NC 28607 PH. [phone]

Photo Nine: View looking east toward the South
Toe River at the eroded slope and river bank area.
Slope repair, sediment removal, and stabilization
complete. Matting is visible with grass beginning
to germinate.
Photo Eleven: View looking east at toe of slope.
River bed with natural substrate visible.
Photo Ten: View looking west at the South Toe
River at area where bank was repaired and
stabilized. Matting is visible with grass beginning
to germinate.
Photo Twelve: View looking west at area where
sediment was removed from the river bed.
Natural river bed substrate can be seen at the
river bank and at bottom of photo.
SEDIMENT REMOVAL AND MMcGill
PHOTO SHEET 3 PROJECT # BANK STABILIZATION
AUGUST 9, 2016 12.00404 A S S O C I A T E S
YANCEY COUNTY, NORTH CAROLINA ENVIRONMENTAL • FINANCE
468 NEW MARKET BLVD. STE B BOONE, NC 28607 PH. [phone]