20200634 Ver 1_Hudson - Corrective Action Plan 050820_20200512

CORRECTIVE ACTION PLAN
STORM DRAIN COMPLIANCE
TOWN OF HUDSON –
HOLLY HILL STREET AND HICKMAN AVENUE
STORM DRAIN REPAIRS PROJECT
CALDWELL COUNTY, NORTH CAROLINA

1013 State Farm Road
Boone, North Carolina, 28607
828.386.1920
Firm License No.: C-0459
MARCH 2020
PROJECT NO. 19.01412
CORRECTIVE ACTION PLAN
STORM DRAIN COMPLIANCE
TOWN OF HUDSON –
HOLLY HILL STREET AND HICKMAN AVENUE
STORM DRAIN REPAIRS PROJECT
CALDWELL COUNTY, NORTH CAROLINA
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page i
TABLE OF CONTENTS
1.0 INTRODUCTION ................................................................................ 1
2.0 STREAM IMPROVEMENT PLAN ......................................................... 4
2.1 HOLLY HILL STREET SITE ............................................................................... 4
2.2 HICKMAN AVENUE SITE ............................................................................... 6
2.3 MONITORING PLAN ..................................................................................... 8
2.4 SCHEDULE/TIMELINE ................................................................................... 8
3.0 FINAL REPORT .................................................................................. 9
APPENDICES – MAP FIGURES and PHOTO SHEETS
1.Location Map
2.USGS Topo Map
3.Aerial Map
4.Holly Hill Stream Improvement Plan
5.Hickman Avenue Stream Improvement Plan
6.Flexi Baffle Specifications
7.Curlex® Bloc Specifications
8.Photo Sheet 1
9.Photo Sheet 2
10.Photo Sheet 3
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 1
1.0 INTRODUCTION

The Town of Hudson - Holly Hill Street and Hickman Avenue Storm Drain Repairs Project
Consists of two small (approx. 3,500sf) areas along Hickman Avenue and Holly Hill Street
within the Town of Hudson Town limits, Caldwell County North Carolina. The project
consisted of the repair of erosion and washout resulting from significant rainfall and the
flooding of an unnamed tributary (UT) to Little Gunpowder Creek (C) at the Hickman
Avenue stream crossing between Hickory Street and Boxwood Street, and at the Holly Hill
Street stream crossing near Elm Avenue (see Location Map). Holly Hill Street repairs
consisted of the replacement of two approx. 45lf culvert pipes and concrete headwalls,
and repair of asphalt road and road shoulders. Hickman Avenue repairs consisted of the
replacement of two approx. 48lf culvert pipes and concrete headwalls, and repair of
asphalt road, road shoulders, and curb and gutter.

On March 5, 2020, Amy Annino from the Asheville Regional Office of the Division of
Water Resources (DWR) conducted a site inspection of two recently installed double
culverts on Hickman Avenue and Holly Hill Street in Hudson, North Carolina. The Town of
Hudson owns and maintains both roads and had recently repaired the culverts. The site
inspection was conducted after receiving notification from the US Army Corps of
Engineers (USACE) that the culverts had not been installed properly. DWR staff met with
officials from the Town of Hudson, Brandee Boggs with the US Army Corps of Engineers,
and with Jon Swaim and Matt Oetting from McGill Associates, P.A.

During the site inspection, recently installed culverts on Hickman Avenue and Holly Hill
Street were observed to have been constructed in a manner that do not meet 401 Water
Quality Conditions or the terms and conditions of a Nationwide Permit #3. The 48-inch
culverts at Hickman Avenue and Holly Hill Street were not installed 20 percent below the
elevation of the streambed to allow for low flow passage of water or aquatic life. In
addition, the distance between the parallel 48-inch culverts at both crossings have
resulted in the over-widening of the stream channel. It was noted that the riprap installed
for bank stabilization at both sites may not be adequately sized, and there were no signs
of filter cloth placement underneath the riprap. Staff also observed that concrete had
been poured over rip rap in the stream channel against the culvert head wall on Holly Hill
Street. No direct contact between uncured or curing concrete and waters of the state are
allowed.

Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 2
A Notice of Violation and Recommendation for Enforcement (NOV-2020-PC-0147) was
received from DWR dated March 11, 2020. A review of DWR files indicates no approval
has been issued for the project. As a result of the site inspection and file review, the
following violations were identified:

VIOLATIONS
I. Failure to Secure a 401 Water Quality Certification (WQC) – Title 15A NCAC 02H .0500
requires water quality certifications pursuant to Section 401 of the Clean Water Act
whenever construction or operation of facilities will result in a discharge into jurisdictional
waters, including wetlands, as described in 33 CFR Part 323. A file review confirmed that
a Pre-Construction Notification has not been received by the DWR for this project and
that a 401 Water Quality Certification has not been issued.

II. Stream Standard Violation –Conditions of Best Usage - 15A NCAC 02B.0211 (2) –
The culverts installed on Hickman Ave and Holly Hill Street do not meet Condition II. 11
of WQC 4132. The improper culvert installations have resulted in an over-widened stream
channel and will not allow for the low flow passage of water or aquatic life, all of which is
a violation of Title 15A North Carolina Administrative Code 02B .0211 (2) which requires
that “The waters shall be suitable for aquatic life propagation and maintenance of
biological integrity, wildlife, secondary recreation, and agriculture; sources of water
pollution which preclude any of these uses on either a short-term or long-term basis shall
be considered to be violating a water quality standard.”

A Notification of Permit Noncompliance was received from the USACE (SAW 2019-02332)
dated March 24, 2020. Description of Activity: This project was permitted under a non-
notifying Nationwide Permit #3 for maintenance and repairs however it fails to meet the
terms and conditions of the permit thereby putting it in a non-compliance status. Below
are the conditions that appeared to fail to meet compliance and will need addressing.
3.4 - Restriction on Use of Live Concrete - For all NWPs which allow the use of concrete
as a building material, live or fresh concrete, including bags of uncured concrete, may not
come into contact with the water in or entering into waters of the United States. Water
inside coffer dams or casings that has been in contact with wet concrete shall only be
returned to waters of the United States after the concrete is set and cured and when it
no longer poses a threat to aquatic organisms.
3.5 - Requirements for Using Riprap for Bank Stabilization - For all NWPs that allow for
the use of riprap material for bank stabilization, the following measures shall be applied:
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 3
3.5.1. - Where bank stabilization is conducted as part of an activity, natural design,
bioengineering and/or geoengineering methods that incorporate natural durable
materials, native seed mixes, and native plants and shrubs are to be utilized to the
maximum extent practicable.
3.5.2. - Filter cloth must be placed underneath the riprap as an additional requirement of
its use in North Carolina waters. The placement of filter fabric is not required if the riprap
will be pushed or “keyed” into the bank of the waterbody. A waiver from the
specifications in this Regional Condition may be requested in writing. The waiver will only
be issued if it can be demonstrated that the impacts of complying with this Regional
Condition would result in greater adverse impacts to the aquatic environment.
3.5.5. - Riprap shall be of a size sufficient to prevent its movement from the authorized
alignment by natural forces under normal conditions.

3.6 Requirements for Culvert Placement
3.6.1 - For all NWPs that involve the construction/installation of culverts, measures will
be included in the construction/installation that will promote the safe passage of fish and
other aquatic organisms. The dimension, pattern, and profile of the stream above and
below a pipe or culvert should not be modified by altering the width or depth of the
stream profile in connection with the construction activity. The width, height, and
gradient of a proposed culvert should be sufficient to pass the average historical low flow
and spring flow without adversely altering flow velocity. Spring flow is the seasonal
sustained high flow that typically occurs in the spring. Spring flows should be determined
from gage data, if available. In the absence of such data, bank-full flow can be used as a
comparable indicator.
3.6.5 - The width of the culvert shall be comparable to the width of the stream channel.
If the width of the culvert is wider than the stream channel, the culvert shall include
baffles, benches and/or sills to maintain the width of the stream channel. A waiver from
this condition may be requested in writing; this request must be specific as to the
reason(s) for the request. The waiver will be issued if it can be demonstrated that it is not
practicable or necessary to include baffles, benches or sills and the design would result in
less impacts to the aquatic environment.

McGill Associates environmental specialists visited the site on February 21, 2020 and
March 5, 2020 to assess the repair work. The intent of McGill Associates was to replace
the damaged existing CMP culverts and concrete headwalls matching the original lengths
and elevations. The existing 48” corrugated metal pipes (CMP) at both locations were
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 4
upgraded to 48” concrete pipes for added durability and life span. The existing concrete
headwalls at the Holly Hill location were replaced with matching concrete headwalls. The
existing concrete headwalls at the Hickman location were upgraded to concrete
headwalls with wing walls and concrete floor. McGill was under the assumption that these
repairs could be considered exempt since the existing culverts and headwalls were being
replaced in kind with improvements. However, after consultation with DWR and the
USACE it was determined that the repairs would fall under a Water Quality Certification
4132 with DWR and a Nationwide Permit #3 with USACE requiring that the repairs adhere
to the corresponding specific conditions such as allowing for the low flow passage of
water or aquatic life. This Corrective Action Plan (CAP) is in response to the above-
mentioned NOV and Notification of Permit Noncompliance. In response to Violation I,
McGill Associates is prepared to complete and submit an after the fact Pre-Construction
Notification to bring the existing and proposed work under compliance with Sections 401
and 404 of the Clean Water Act. In addition, McGill Associates has created a Stream
Stabilization Plan and Monitoring Plan for the two impact areas along UT-Little
Gunpowder Creek which are proposed to address Violation II and Permit Noncompliance.

2.0 STREAM IMPROVEMENT PLAN

During the site meeting on March 5, 2020 the DWR and the USACE expressed their
concerns with the new culvert installations at both locations which have resulted in an
over-widened stream channel and will not allow for the low flow passage of water or
aquatic life (see Photo Sheets). McGill Associates has coordinated with the Town of
Hudson to remedy these issues with an instream structure design at the Holly Hill site,
and a combination of streambank stabilization and baffle installation at the Hickman
Avenue site.
2.1 HOLLY HILL STREET SITE

In order to bring the recently installed Holly Hill Street culverts into compliance, Mcgill is
proposing to construct a boulder Cross-Vane (CV) structure just downstream of the outlet
end of the culverts. The CV has been designed to remedy Violation II – Stream Standard
Violation and Permit Noncompliance by raising the base flow level of the stream,
mimicking culvert burial, and allowing for the low flow passage of water or aquatic life.
CV elevations were designed to raise the base flow elevation of the stream a minimum of
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 5
9.6-inches above the inlet invert elevation of the pipes. The CV will also act as a grade
control structure that decreases near-bank shear stress, velocity, and stream power,
while increasing the energy in the center of the channel. The CV structure is intended to
reduce bank erosion, create a stable width/depth ratio, and maintain channel capacity
while maintaining sediment transport capacity and sediment competence. The CV
provides for the proper natural conditions of secondary circulation patterns
commensurate with channel pattern, but with high velocity gradients and boundary
stress shifted from the near-bank region. By concentrating stream flow directly from the
pipe outlets back to the center of the channel, we believe that the CV will remedy the
issue of over-widening. See Appendix 4 – Holly Hill Stream Improvements Plan.

In addition to the culvert installation issues, it was noted during the site visit that concrete
had been poured over rip rap in the stream channel against the culvert head wall (see
Photo Sheets). McGill does not have access to photo documentation of the concrete being
poured in a manner consistent with USACE permit conditions. DWR has requested that
this concrete and any rip rap containing concrete should be removed from the stream
channel. The concrete and rip rap will be removed and disposed of at an off-site facility
that accepts this type of waste. Also, during the site visit flowing water was observed
exiting an orifice in the outlet headwall between the headwall and culvert pipes. Stream
flow will be pumped around or diverted via approved alternative method, the orifice will
be sealed off by pumping concrete into the opening until sealed and will be allowed to
cure for 24 hours before stream flow is returned to normal. No live concrete will come in
contact with stream bed, banks, or stream flows during proposed activities. It was also
noted during the site inspection that geotextile fabric was not visible beneath the recently
installed rip rap. Existence of the fabric should be confirmed via photo documentation for
both the upstream and downstream areas, or the rip rap will need to be removed and
reinstalled with a geotextile fabric base. The rip rap should be adequately sized to avoid
movement during high flow conditions. Any disturbed streambank located upstream or
downstream of the areas disturbed during headwall installation will be stabilized using
vegetative measures including fully biodegradable matting, native seed mix, and native
live stakes. Riprap was installed along road slopes and headwall areas for erosion
protection from stormwater flow associated with Holly Hill Street. Vegetative stabilization
measures in these areas may not provide adequate protection and result in erosion
issues. McGill is prepared to submit a PCN identifying the installed riprap as permanent
stream impacts.

Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 6
During all instream improvement work a pump-around or other approved flow diversion
will be utilized so that all work may occur in the dry. Instream work will be avoided during
significant rain events and/or during increased stream flow. Once construction is
completed, disturbed streambanks will be returned to original conditions and stabilized
with fully biodegradable matting, a native North Carolina riparian seed mix, and native
live stakes.
2.2 HICKMAN AVENUE SITE

The Hickman Avenue site will be brought into compliance by stabilizing upstream and
downstream banks which have become eroded, and by retro-fitting culvert baffles which
are designed to reduce downstream velocity, divert flow to the center of the channel,
and assist with aquatic species passage during low flow, mimicking pipe burial. We believe
that these improvements to the Hickman Avenue site will resolve Violation II – Stream
Standard Violation and Permit Noncompliance.

In order to bring the recently installed Hickman Avenue culverts into compliance, McGill
is proposing the stabilization/armoring of an approximate 25lf section of the left bank just
upstream of the culvert inlet with Curlex® Bloc high density coir log for toe protection.
See Appendix 5 - Curlex® Bloc Detail and Appendix 7 - Curlex® Bloc Specifications. Existing
rip rap along the 25lf section streambank will be removed and replaced with fully
biodegradable matting, native NC riparian seed mix, and native live stakes. A small
exposed section of the right bank will be sloped back by hand as much as possible without
damaging existing vegetation and stabilized with fully biodegradable matting, native NC
riparian seed mix, and native live stakes. See Photo Sheets and Appendix 5 - Hickman
Avenue Stream Improvement Plan.

An approximate 15lf section of the right bank downstream of the culvert outlet will also
be stabilized/armored with Curlex® Bloc high density coir log for toe protection. See
Curlex® Bloc Detail – Appendix 5 - Hickman Avenue Stream Improvement Plan. A layer
(approx. 6-12 inches) of topsoil will be added to the streambank above the coir log to
achieve a positive grade and allow for native seed germination. After coir log and topsoil
application, the streambank area above the coir log will be stabilized with fully
biodegradable matting, native NC riparian seed mix, and native live stakes. This section of
streambank has historically received over bank flows during storm events. The coir log
toe protection is intended to armor the existing streambank, while allowing high flows to
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 7
access the above flood bench. The matting, seeding, and live stakes are intended to aid
in flood bench stabilization without permanently damaging existing riparian vegetation
and root mat. See Appendix 5 - Hickman Avenue Stream Improvement Plan.
A low impact solution is being proposed to mimic pipe burial by installing Flexi Baffles
within the two culverts, which will raise the base flow level of the stream and allow for
the low flow passage of water or aquatic life. The Flexi Baffles can be installed within the
existing culverts resulting in no impacts to stream bed or banks. The baffles are designed
to reduce velocity, increase depth, interrupt laminar flow, extend the range of flow
characteristics, retain streambed material, and create high and low flow passage for the
small aquatic organisms which live in UT to Little Gunpowder Creek. It is estimated that
during low flow or normal flow conditions the baffles have the capability of raising flow
in the pipes up to 6 to 9-inches. The Flexi Baffle is designed to lay back during high flow
events, then right itself as water flow drops, creating hydraulic conditions that allow fish
and other aquatic organisms to transit the culvert. Baffles will be installed at 4-foot
spacing within the culverts to mimic upstream and downstream reference reach riffle
pool sequences. In addition to installing the baffles for low flow and aquatic organism
movement, a 10-foot section of baffles will be extended along the outside diameter of
each culvert to force stream flow to the center of the channel during bank full events.
This flow diversion is intended to reduce downstream bank erosion and maintain channel
capacity by concentrating stream flow directly from the pipe outlets back to the center of
the channel. See Appendix 5 - Hickman Avenue Stream Improvement Plan and Appendix
6 - Flexi Baffle Specifications.
Coir log was chosen for streambank toe protection over large boulders since it can be
installed by hand and does not require equipment access and extensive grading which
would result in root damage within the streambanks and damage to existing riparian
vegetation and large trees. The coir log will provide bank protection, buffer flow velocity,
and will support vegetative growth without requiring significant excavation. The Flexi
Baffles were chosen based on the same reasoning. While performing design calculations
for a CV below the culvert outlets it was discovered that the CV weir elevation would need
to be 24-inches above pipe inverts to allow for the recommended 9.6-inches of fill within
the inlet of two culverts. This amount of increased flow within the stream channel and
culverts in addition to the necessary size of the CV would create issues during high flow
events such as flooding and streambed scour. Constructing a large instream structure
downstream of the outlet such as a CV would also require equipment access and grading
into the streambanks resulting in root damage and potential loss of riparian vegetation.
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 8
There are several mature trees along the right bank below the culvert outlet which would
be damaged during construction resulting in an unstable streambank long term and
potential tree loss. It was also noted during the site inspection that geotextile fabric was
not visible beneath the recently installed rip rap. The contractor provided verbal and
photo documentation that geotextile fabric had been installed beneath all rip rap as
specified in project plans. See Photo Sheets. During culvert installation the contractor
discovered bedrock at or near streambed elevation at the new culvert outlet. Excavation
for instream structure would be limited in this area and proper anchoring of boulder
material would be compromised. Riprap was installed along road slopes and headwall
areas for erosion protection from stormwater flow from road surface and curb and gutter
associated with Hickman Avenue. Vegetative stabilization measures in these areas may
not provide adequate protection and result in erosion issues. McGill is prepared to submit
a PCN identifying the installed riprap as permanent stream impacts.
During all instream improvement work a pump-around or other approved flow diversion
will be utilized so that all work may occur in the dry. Instream work will be avoided during
rain events and/or during increased stream flow. Once construction is completed,
disturbed streambanks will be returned to original conditions and stabilized with fully
biodegradable matting, a native North Carolina riparian seed mix, and native live stakes.
2.3 MONITORING PLAN
A McGill Associates or other approved representative will perform periodic site
inspections for 1-year post construction completion and agency approval. Inspections will
be performed at least quarterly and after significant rain events that result in bankfull
flows of UT-Little Gunpowder Creek. During site inspections the representative will
produce written and photo documentation of overall site conditions and stream stability.
If stream improvements have been compromised beyond working condition, all
appropriate agencies will be contacted and a remediation plan will be put in place.
2.4 SCHEDULE/TIMELINE
Once CAP approval and required permits have been obtained from all appropriate
agencies (approx. 30 – 45 days), the proposed instream work can be initiated. Once
construction activities have commenced, we anticipate 30 to 60 days for project
Town of Hudson, NC
Holly Hill Street and Hickman Avenue
Storm Drain Repairs Project
Corrective Action Plan
March 2020 Page 9
completion depending on weather and stream flow conditions. Monitoring activities will
extend for 1-year post construction.
4.0 FINAL REPORT
The Town of Hudson has authorized McGill Associates, PA to act as an independent third-
party inspection firm to visit the site during stream improvement efforts to identify
deficiencies and corrective action to be taken in order to bring the sites into compliance.
Any deviations from the plans included in this Corrective Action Plan, will be
communicated to the proper permitting authorities and recommendations will be
provided to the Contractor as needed based on our previous experience with similar
projects.
Status reports will be created by a McGill Associates, P.A. representative or other qualified
individual as needed until completion of the Corrective Action Plan. Progress related to
stream improvements to the UT to Little Gunpowder Creek will be incorporated into the
reports. Status reports will be distributed to NC DWR and any other necessary parties for
comment.
Upon completion of the Corrective Action Plan a Final Report will be completed by a
McGill Associates, P.A. representative. The Final Report will contain a description of the
completed work, the results of the stream improvement activities, and photo
documentation. The Final Report will be distributed to NC DWR and any other
necessary parties for comment.
Once approval of the Final Report is received from NCDWR and the USACE, the Town of
Hudson will be responsible for maintaining the culvert systems.
Appendix 1
Location Map
© 2020 Microsoft Corporation © 2020 HERE
500 0 250 500 1000
500DIVISION VALUE = FEETGRAPHIC SCALE
LOCATION MAP 1
FIGURE
CALDWELL COUNTY, NORTH CAROLINA
Town of Hudson
Hickman Avenue &
Holly Hill Street Repairs3/18/2020
DATE
19.01412
PROJECT #
MO
PROJECT MANAGER
P:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\FIGURES.DWG PLOT DATE 3/18/2020 2:46 PM ALEX LOWDERMILK1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com
Project Area
Project Area
Appendix 2

USGS Map

500 0 250 500 1000
500DIVISION VALUE = FEETGRAPHIC SCALE
USGS MAP 2
FIGURE
CALDWELL COUNTY, NORTH CAROLINA
Town of Hudson
Hickman Avenue &
Holly Hill Street Repairs3/18/2020
DATE
19.01412
PROJECT #
MO
PROJECT MANAGER
P:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\FIGURES.DWG PLOT DATE 3/18/2020 2:55 PM ALEX LOWDERMILK1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com
Project Area
Project Area
Appendix 3

Aerial Map

100 0 50 100 200
100DIVISION VALUE = FEETGRAPHIC SCALE
AERIAL MAP 3
FIGURE
CALDWELL COUNTY, NORTH CAROLINA
Town of Hudson
Hickman Avenue &
Holly Hill Street Repairs3/18/2020
DATE
19.01412
PROJECT #
MO
PROJECT MANAGER
P:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\FIGURES.DWG PLOT DATE 3/18/2020 3:39 PM ALEX LOWDERMILK1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com
Hickman Avenue
Holly Hill Street
UT- Little Gunpowder Creek
Appendix 4

Holly Hill Stream Improvement Plan

EXISTING CONDITIONS LEGEND
CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HOLLY HILL STREET
STREAM IMPROVEMENT PLAN
SCHEDULE OF DRAWINGS
MARCH 2020
VICINITY MAP
G-001 . . . . . COVER SHEET
G-002 . . . . . GENERAL NOTES AND LEGENDS
C-101 . . . . .PLAN and PROFILE
C-501 . . . . .CONSTRUCTION DETAILS
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P:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\19.01412_STREAM PLAN.DWG PLOT DATE 3/18/2020 6:49 PM JONATHAN M. HERMANmcgillassociates.com
1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459 19.01412 TOWN OF HUDSON HOLLY HILL and HICKMAN WASHOUT REPAIRS
GENERAL NOTES AND LEGENDS1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HOLLY HILL STREET
STORM DRAIN REPAIRS AS NOTED
19.01412 N/A
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SHEET
OFFICE MANAGER
PROJECT MANAGER
DESIGNER
REVIEWER DATE PROJECT #FUNDING #
CTV
000000000000000000000000000000000nnnEXISTING CONDITIONS LEGEND
XX.XXXXX CITY OF McGILLINGTON WATER DISTRIBUTION SYSTEM IMPROVEMENTSGENERAL NOTES:
GENERAL CONSTRUCTION NOTES
######nnnnnnnnnnnnnnnnnn######PROPOSED CONDITIONS
PROPOSED SYMBOLS PROPOSED ABBREVIATIONS
PROPOSED LINE TYPES
D. CHAPMAN
M. OETTING
J. HERMAN
J. SWAIM MARCH 2020
STREAM IMPROVEMENT
PLAN AND PROFILE 19.01412 TOWN OF HUDSON HOLLY HILL and HICKMAN WASHOUT REPAIRS1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HOLLY HILL STREET
STORM DRAIN REPAIRS
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SHEET
OFFICE MANAGER
PROJECT MANAGER
DESIGNER
REVIEWER DATE PROJECT #FUNDING #
PROFILE
SCALE: HORIZ. 1"= 10'
VERT. 1"= 2'
PLAN
SCALE: 1"= 10
D. CHAPMAN
M. OETTING
J. HERMAN
J. SWAIM
STREAM IMPROVEMENT
DETAILS 19.01412 TOWN OF HUDSON HOLLY HILL and HICKMAN WASHOUT REPAIRS1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HOLLY HILL STREET
STORM DRAIN REPAIRS
DIVISION VALUE = FEETGRAPHIC SCALE
50 0 25 50 100
50
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D. CHAPMAN
M. OETTING
J. HERMAN
J. SWAIM 19.01412 N/A
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SHEET
OFFICE MANAGER
PROJECT MANAGER
DESIGNER
REVIEWER DATE PROJECT #FUNDING #
TEMPORARY STREAM BYPASS
NOT TO SCALE
PLANELEVATION
·
·
·
·
·
·
®
®
®
®
CROSS VANE DETAIL
NOT TO SCALE
BIODEGRADEABLE COIR MATTING DETAIL
NOT TO SCALE
®
®
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®
MARCH 2020
SQUARE CUT
BUDS (FACING UPWARD)
LIVE CUTTING
(12"-112" DIAMETER)
ANGLE CUT 30-45
DEGREES
2-3 FEET IN
LENGTH
LIVE STAKES
LIVE STAKE INSTALLATION
NOT TO SCALE
STREAMBANK STABILIZATION SEEDING NOTES
Appendix 5

Hickman Avenue Stream Improvement Plan

EXISTING CONDITIONS LEGEND
CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HICKMAN AVENUE
STREAM IMPROVEMENT PLAN
SCHEDULE OF DRAWINGS
MARCH 2020
VICINITY MAP
G-001 . . . . . COVER SHEET
G-002 . . . . . GENERAL NOTES AND LEGENDS
C-101 . . . . .PLAN and PROFILE
C-501 . . . . .CONSTRUCTION DETAILS
C-502 . . . . .CONSTRUCTION DETAILS (2)
500 0 250 500 1000
500DIVISION VALUE = FEETGRAPHIC SCALE
P:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\19.01412_STREAM PLAN.DWG PLOT DATE 3/18/2020 6:41 PM JONATHAN M. HERMANmcgillassociates.com
1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459 19.01412 TOWN OF HUDSON HOLLY HILL and HICKMAN WASHOUT REPAIRS
GENERAL NOTES AND LEGENDS XX.XXXXX CITY OF McGILLINGTON WATER DISTRIBUTION SYSTEM IMPROVEMENTS1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HICKMAN AVENUE
STORM DRAIN REPAIRS AS NOTED
19.01412 N/A
G-002RCALL811BEFOREY
O
U
DGI
SAF
E DIGGING P A R TNERP:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\19.01412_STREAM PLAN.DWG PLOT DATE 3/18/2020 6:41 PM JONATHAN M. HERMANNO.DATE BY DESCRIPTION
SHEET
OFFICE MANAGER
PROJECT MANAGER
DESIGNER
REVIEWER DATE PROJECT #FUNDING #
D. CHAPMAN
M. OETTING
J. HERMAN
J. SWAIM MARCH 2020
CTV
000000000000000000000000000000000nnnEXISTING CONDITIONS LEGEND
GENERAL NOTES:
GENERAL CONSTRUCTION NOTES
######nnnnnnnnnnnnnnnnnn######PROPOSED CONDITIONS
PROPOSED SYMBOLS PROPOSED ABBREVIATIONS
PROPOSED LINE TYPES
BANK STABILIZATIONPLAN19.01412 TOWN OF HUDSON HOLLY HILL and HICKMAN WASHOUT REPAIRS1013 State Farm RoadBoone, NC 28607828.386.1920NC Firm License # C-0459mcgillassociates.comCALDWELL COUNTY, NORTH CAROLINATOWN OF HUDSONHICKMAN AVENUESTORM DRAIN REPAIRSDIVISION VALUE = FEETGRAPHIC SCALE502.55105019.01412N/AC-101RCALL811BEFOREYOUDGISAFE DIGGING PARTNERP:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\19.01412_STREAM PLAN JS EDITS.DWG PLOT DATE 3/23/2020 10:59 AM JONATHAN M. HERMANNO.DATEBYDESCRIPTIONSHEETOFFICE MANAGERPROJECT MANAGERDESIGNERREVIEWERDATEPROJECT #FUNDING #PROFILESCALE: HORIZ. 1"= 10' VERT. 1"= 2'PLAND. CHAPMANM. OETTINGJ. HERMANJ. SWAIMMARCH 2020
STREAM IMPROVEMENT
DETAILS 19.01412 TOWN OF HUDSON HOLLY HILL and HICKMAN WASHOUT REPAIRS1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HICKMAN AVENUE
STORM DRAIN REPAIRS
DIVISION VALUE = FEETGRAPHIC SCALE
50 0 25 50 100
50
0
D. CHAPMAN
M. OETTING
J. HERMAN
J. SWAIM 19.01412 N/A
C-501RCALL811BEFOREY
O
U
DGI
SAF
E DIGGING P A R TNERP:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\19.01412_STREAM PLAN.DWG PLOT DATE 3/18/2020 6:41 PM JONATHAN M. HERMANNO.DATE BY DESCRIPTION
SHEET
OFFICE MANAGER
PROJECT MANAGER
DESIGNER
REVIEWER DATE PROJECT #FUNDING #
PIPE BAFFLE DETAIL
NOT TO SCALE
MARCH 2020
CURLEX BLOC DETAIL
NOT TO SCALE
NOTE:
FOR MORE INFORMATION CONTACT SUPPLIER:
S. SCOTT & ASSOCIATES LLC
4719 NE SALMON CREEK ST
VANOUVER, WA 98686
PHONE: [phone]
EMAIL: [e-mail]
STREAM IMPROVEMENT
DETAILS 19.01412 TOWN OF HUDSON HOLLY HILL and HICKMAN WASHOUT REPAIRS1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com CALDWELL COUNTY, NORTH CAROLINA
TOWN OF HUDSON
HICKMAN AVENUE
STORM DRAIN REPAIRS
DIVISION VALUE = FEETGRAPHIC SCALE
50 0 25 50 100
50
0
D. CHAPMAN
M. OETTING
J. HERMAN
J. SWAIM 19.01412 N/A
C-502RCALL811BEFOREY
O
U
DGI
SAF
E DIGGING P A R TNERP:\2019\19.01412-HUDSONNC-HOLLYHILL HICKMAN WASHOUT REPAIRS\DESIGN\PERMITS\19.01412_STREAM PLAN JS EDITS.DWG PLOT DATE 3/23/2020 11:02 AM JONATHAN M. HERMANNO.DATE BY DESCRIPTION
SHEET
OFFICE MANAGER
PROJECT MANAGER
DESIGNER
REVIEWER DATE PROJECT #FUNDING #
MARCH 2020
PLANELEVATION
·
·
·
·
·
·
®
®
®
®
BIODEGRADEABLE COIR MATTING DETAIL
NOT TO SCALE
®
®
®
®
SQUARE CUT
BUDS (FACING UPWARD)
LIVE CUTTING
(12"-112" DIAMETER)
ANGLE CUT 30-45
DEGREES
2-3 FEET IN
LENGTH
LIVE STAKES
LIVE STAKE INSTALLATION
NOT TO SCALE
STREAMBANK STABILIZATION SEEDING NOTES
TEMPORARY STREAM BYPASS
NOT TO SCALE
Appendix 6

Flexi Baffle Specifications

This case study forms part of a series that provides
key information and guidance about how to
potentially improve a fish passage barrier in a New
Zealand waterway.
While providing fish passage is advantageous to
most fish, removing or remediating a barrier can
also affect fish populations by introducing invasive
species to new areas.

What was the problem? What was the solution?
Reservoir Creek is a small, coastal stream that runs
through urban Nelson. Approx. 1.5km inland from the
coast, the stream has a highly complex pipe culvert
system. The 1.6m diameter round culvert is 136m long
and bed gradients range from 1°-30° (Figure 1). The
culvert is made up of different culvert materials
(concrete and metal) and has several directional
changes left and right. Eels (Anguilla dieffenbachia,
Anguilla australis), banded kokopu (Galaxias fasciatus)
and common bully (Gobiomorphus cotidianus) were
found upstream and downstream of the culvert, while
inanga (Galaxias maculatus), and redfin bully
(Gobiomorphus huttoni) were only found downstream.
Based on observation, high barrel water velocities due
to the steepness of culvert gradients were considered
an impediment to successful upstream passage of fish,
particularly the weaker swimming fish species such as
inanga and bullies.
The aim for this work was to restore upstream passage
for all fish species without compromising culvert
capacity and causing blockages. We also wanted to
provide in-pipe habitat for fish in the form of pools.

In April 2018 a total of 79 flexible baffles (“Flexi-
baffles”) were secured to the culvert base to reduce
water velocities and create resting pools within the
culvert (Figure 2). Flexible baffles differ from regular
weir shaped baffles because they offer fish passage
around the baffle edges in a variety of flow regimes
(Figure 3). The baffles are made of flexible polymer and
are 600mm wide and 100mm high (Figure 2). The
baffles were attached to the concrete culvert floor with
stainless-steel sleeve anchors (M6.5 x 40mm) with
stainless steel penny washers (32mm), and attached to
the metal section with stainless steel tek-screws
(14Gx25mm) with stainless-steel penny washers
(32mm).
The spacing between baffles, and therefore the
number of baffles installed, was determined by the
culvert gradients (i.e. more baffles were installed in
shorter intervals where gradients were steeper (Figure
4)).
Flexible baffles were used as they are robust, can shed
large debris, and bend in high flows to maintain culvert
capacity.
Installation of baffles to restore fish passage in a very long
culvert
Lessons Learnt 008
May 2019
* Success rating: 5/5 – Excellent improved passage for all
species.
SUCCESS RATING*
5/5
STRUCTURE TYPE

Figure 1 – Cross section of the Reservoir Creek Culvert showing the changes in gradient.

Figure 2 – Lower section of culvert before (left) and after Flexi-baffle installation (right).

Figure 3 – Each baffle is cut at 45° on either side (A) to allow water to spill around the baffle (B) and therefore enables fish
passage past the baffle, even at low flows (Note: figures not from Reservoir Culvert).
Flow type: Laminar
Max depth: 40mm
Wetted width: 450mm
Mean velocity: 1.5m/s
Mean pool length: 0mm

Before

After

Flow type: Complex
Max depth: 100mm
Wetted width: 850mm
Mean velocity: 0.3m/s
Mean pool length: 2200mm

Figure 4 – Cross section of the Reservoir Creek Culvert showing the number of baffles installed.
Monitoring results
Fish survey data was collated from surveys completed between 2008 and 2019, upstream of the Reservoir Creek
Culvert (Source: NZ Freshwater Fish Database).
Monitoring showed an additional two fish species upstream of the culvert post installation of the flexible baffles
(i.e. inanga and redfin bully). Common bully abundance has also increased following the fish passage restoration,
however, eel numbers have dropped (Figure 5).

Figure 5 – Results of fish community monitoring before and after baffle installation upstream of the culvert over time.
Did it work?
Installation of flexible baffles in a long round culvert can overcome migration barriers for weak swimming fish and
can enhance the composition of the upstream fish community. Healthy numbers of inanga and common bullies
now exist upstream of the culvert, with redfin bullies appearing to populate the area also. Fish have been
observed resting and feeding between baffles in the culvert barrel. During a pass through the culvert in January
2019, forty fish were identified within the culvert including shortfin eel, longfin eel, inanga and common bully
(Figure 6). This suggests that as well as providing passage through the culvert, the baffles also provide suitable
conditions for fish within the pipe system.

Figure 6 – Photo A shows an eel strategically placed for feeding in a pool upstream of a Flexi-baffle. Photo B shows three
common bully resting in a pool upstream of a baffle near the top of the culvert.
Lessons learnt
1. Flexible baffles have shown to be an effective solution for providing fish passage through a complex long
culvert in Reservoir Creek.
2. Fish were observed feeding in pools between baffles and using the baffles as refuge.
3. The exact size and spacing between flexible baffles have not been prescribed and installations will differ
depending on culvert characteristics (length, diameter, gradient, and flow rate etc).
4. Subsequent culvert inspections 12 months following the installation have found all baffles remain secured
to the culvert base, therefore the fixing methodology used for this installation appears appropriate to
date.
5. To date there have been no reports of blockages within the culvert barrel as a result of the installation of
flexible baffles.
6. Ideally some bed material should be retained to create a more diverse environment within the pipe.
Minimal bed material has been retained at this culvert. This is likely due to the upstream gravel trap
stopping the natural movement of material downstream.
7. Pre and post remediation fish monitoring at upstream and downstream would be ideal.
For further information
Contact:
Tim Olley ([e-mail])

Thanks to Tasman District Council for supporting the project

SSA - FLEXI BAFFLES®
The Flexi Baffle is designed to reconnect aquatic habitat above and below a passage barrier. The
Flexi Baffle creates hydraulic conditions within a culvert that allows both strong and weak
swimming fish and other aquatic organisms to pass upstream. The flexible baffle material allows
the the weir to lay down at higher flows to preserve the hydraulic capacity of the culvert and reduce
the incidence of capturing debris. When flows drop, the Flexi Baffle reorients itself to create a fish
ladder in your culvert. The Flexi Baffle can be easily installed prior to new culvert installation or be
used to retrofit to existing structures.
Almost 1,000 Flexi Baffle installations have been established over the last 10 years for a variety of
fish and other aquatic species. Let our fish passage experts help design a solution for your barrier.
Features (At-a-Glance)
•Reduces water velocity and interrupts laminar flow to improve fish
passage conditions
•Can be installed in concrete, steel, galvanized or HDPE culverts
•Constructed from rugged, non-toxic EDPM rubber
•Height is 6inches/150mm.
•Length can be customized to your application
•Can be customized to fit any size and shape of culvert
•Can be quickly installed with common hand tools
S.Scott & Associates LLC
4719 NE Salmon Creek St. [phone]
Vancouver, WA 98686 [e-mail]
For more information and videos see: www.sscottandassociates.com/culvert-passage.html
Patent Pending
Flexi Baffle Development and Application:

The Flexi Baffle has been developed over the past ten years by ATS Environmental in New
Zealand as a country wide effort to support collapsing freshwater and marine fisheries. Today,
there are about 1,000 installations through the world ranging from a single baffle to multiple
baffle installations in a 0.5-mile-long culvert. Target species for these installations varied from
salmon and trout (Oncorhynchus spp., Salmo sp., Salvelinus spp.) to eels (Anguilla spp.), shad
and river herring (Clupeid spp.), Galaxias (Galaxiid spp.) and freshwater shrimp (Paratya spp.)
and their forage species.

Biological Justification for the Flexi Baffle:

The Flexi Baffle creates a “weir and pool” hydraulic condition that provides a variety of passage
routes for strong and weak swimming fish and other organisms. This allows habitat connectivity
above and below a culvert. Typically, a fish ladder is designed with weirs to create resting pools
and either slots or orifices to allow organisms to pass to the next pool. The Flexi Baffle creates
step pools through a culvert which allows fish or other aquatic organism to either pass over or
around the weir. Strong swimming species such as salmonids can quickly pass over the Flexi
Baffle as they migrate upstream. Weaker swimming species can pass around the angled end of
the weir. The Flexi Baffle does not create an impediment for downstream passage for any
species. Figure 1 illustrates the hydraulic conditions created at one of the fish ladders at the
Bonneville Dam on the Columbia River and at a Flexi Baffle installation.

Figure 1. Hydraulic Conditions at a Fish Ladder and a Flexi Baffle Installation.

The Flexi Baffle Design:

In the past, rigid weirs were installed in culverts to improve fish passage; there were many
drawbacks. A solid weir spanning the entire culvert created a waterfall at low water conditions.
This configuration likely impeded passage for weak swimming, but important forage species,
such as sculpin (Cottus spp.), crayfish (Pacifastacus spp.) and various insects.

Rigid weirs also adversely affect the hydraulic capacity of culverts. A lot of thought and effort is
required to properly design and install a culvert. Often the designers use the smallest culvert
allowable to reduce cost. By retrofitting a culvert with a solid weir, the hydraulic capacity of the
culverts is further reduced resulting in poor water conveyance and localized flooding.

Lastly, rigid weirs are also susceptible of damage from woody debris or bedload passing through
the culverts. At times, the rigid weirs accumulate debris which further exacerbates the hydraulic
capacity of the culvert and impacts fish passage. This debris must be manually removed which
is often expensive and dangerous for personal conducting the work.

The Flexi Baffle is designed to maintain hydraulic capacity of a culvert while providing upstream
passage for fish and other aquatic organisms. The flexible design allows the baffle to lay nearly
flat with approximately 3-feet of water depth. The Flexi Baffle then rights itself as water flow
drops, creating hydraulic conditions that allow fish and other aquatic organisms to transit the
culvert.

The Flexi Baffle is constructed from EPDM (Ethylene Propylene Diene Monomer). This rugged,
high-density polymer is primarily used for outdoor applications like rubber roofing and
weatherproof seals. It is non-toxic and often used in potable water rain collection systems.
EDPM is also resistant to heat, oxidation, ozone and the weather.

The Flexi Baffle is extruded to a 6-inch height. After hundreds of installations, ATS
Environmental has identified this as the most effective height for culvert passage applications.
The lengths of each weir and spacing is dependent upon the size and slope of the culvert.

The Flexi Baffle is designed to be easily installed in a variety of new or existing culvert
substrates (round or box), to include concrete, steel, fiberglass and HDPE. The Flexi Baffle is
attached to the culvert with either commercially available fixing such as self-tapping screws or
wedge/sleeve anchors.

Recommend Installation:

The number of Flexi Baffles to be installed is dependent upon the length and gradient of your
culvert or other passage barrier. The baffles are spaced to maintain a minimum water depth
below each unit adequate for the largest fish expected to migrate through the culvert to easily
pass from one pool to the next. Our staff can assist you with the number and placement of your
Flexi Baffles.
The Flexi Baffle is installed with simple hand tools. The baffles can be installed in dry or wet
conditions. A team of experienced installers can outfit two to four typical culverts in a single
day.
Recommended Tool list:
•Cordless hammer drill
•Masonry bit to suit fixings selected
•Hammer
•Socket and ratchet (for wedge anchors).
•Cordless impact driver (if Tapcon screws are used)
Recommended Fixings:
We recommend using wedge anchors and washers when attaching the Flexi Baffle to a concrete
culvert. (e. g., M6 x 50 - 316SS Wedge Anchor)
We recommend using self-tapping (e.g. Tapcon) screws with washers when attaching the Flexi
Baffle to a steel, HDPE or other thin walled culvert.
Appendix 7

Curlex® Bloc Specifications

Curlex Bloc Introduction
Customers across North America have been asking for an American -made alternative to coir logs and American Excelsior
Company has answered with the development of Curlex Bloc. Curlex Blocs are manufactured in the U.S.A. with American
fibers, as compared to coir fibers that are typically imported from half way across the planet. Curlex Blocs are designed to
be functional' for 3+ years. The standard biodegradable containment material is designed to start degrading during the
first year to allow voluntary seed and sediment into the Curlex fiber matrix. The matrix of the Curlex Bloc is the key to the
products performance capabilities The containment material is a carrier to assist with product shipping and placement
into the field.
Curlex Blocs are manufactured from Great Lakes Aspen. Curlex Blocs are naturally seed free, non toxic, and native to North
Ampel ca.
U.S. Made with U.S. fibers
Supports U.S. economy and adds jobs; friendly carbon footprint compared to
imported ooir logs.
Made from Cudex
Barbed fibers "cling" to one another to add strength and stability; excellent
natural filters of fines and hydrocarbons
Flat/Rectangular design
Allows for better stability and intimate soil contact
High Density
Better buffering of flow velocity
Organic
Can plant vegetation through matrix and natural fibers degrade over time
Moisture Retention
Promotes healthier growth
Sustainable Material
Renewable resource managed by sustainable forestry programs
Product Name
Curlex Bloc
Curlex Bloc HD
Nominal Diameter
18 in x 16 in
18 in x 16 in
(45.7 cm x 40.6 cm)
(45.7 cm x 40.6 cm)
Length (+ 10%, - 0%)
(2.4 m)
(2.4 m)
Unit Weight (t 10%)
14.0 Ib/ft
18.0 lb/ft
(20.8 kg/m)
(26.8 kg/m)
Unit Ground Contact (minimum)
192 in2/ft
(4,064.2 cm2 / m)
192 in2/ft
(4,064.2 cm' / m)
Density° (t 10%)
7.0 Ib/ft°
9.0 Ib/fN
(112.1 kg/m°)
(144.1 kg/m°)
'Functional Longevity varies from region to region because of differences in climatic conditions.
°Weight and density are based on a dry fiber weight basis at time of manufacture. Baseline moisture content of Great Lakes Aspen excelsior is 22%.
American -
Excelsior -
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Company®
Earth Science Division TMe�fi�
Arlington, Texas (800) 777-SOIL • www.curlex.com

ETTIM m
Curlex Bloc continues to be used in conjunction with vegetation on stream bank restorations and other shoreline applications
with low energy and wave action, but each day contractors are finding new applications for the product such as replacing wire
backed silt fence with Curlex Blocs to protect sensitive wetlands. Using versatile Curlex Blocs as natural filters is becoming
more and more common each day. They are the most effective product we have seen that does not contain flocculating
materials. Let us know if you have a new application for Curlex Bloc.
12 Months 16 Months
(willow live stakes and native sod used in this stream bank application)
1. Contaminated water channelized through Curlex Bloc Filter Station
2. Cross -sectional view of unused Curlex Bloc fibers
3. Clear, clean water exiting Curlex Bloc Filter Station on down slope side
4. Cross -sectional view of fine sediments captured by Curlex Bloc matrix after the flow (containment
material was removed from Curlex Bloc for photo)
Property
Value
Method
Flow Rate (GPM/ft2)
>_ 35
ASTM D5141
Removal of Polynudear Aromatic Hydrocarbons (PAHs) (%)
>_ 95
Quantified research'
Slope Soil Loss Reduction (%)
>_ 68
Quantified research'
pH Buffering
8±3
ASTM D1117, modified
Fly Ash Filtenng (TSS)
>>-95
Quantified research`
Fly Ash Filtration (NTU)
>_ 88
Quantified research`
'Roving and Zhang. Chemosphere 54(200,t)831-8339.
'Kelsey, K., T Johnson and R. Vinim. 2006. "Needed Information: Testing, Analyses, and Performance Values far Slope Interruption and Perimeter Control BMP6' IECA Conference Proceedings. P 171-181.
9(elsey,K.and M. Mudey. (2017, January). Fly Ash Slurry Filfrafion Using Cuden' Blocs - Quanri ag Tataf Suspended Solids and Turbidity Reduction. Unpublished internal document, EmslonL.ab.
vAoem If you would like to receive more information or consult with one of our
Customer Care Center Specialists, please call us toll free at (888-352-9582)
rPDF download specifications available in the Technical Support Library at www.curlex.com
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PHOTOSHEET 1 A-8
FIGURE
CALDWELL COUNTY, NORTH CAROLINA
HOLLY HILL ST AND HICKMAN AVE
TOWN OF HUDSON
STORM DRAIN COMPLIANCE3/20/20
DATE
19.01412
PROJECT #
MO
PROJECT MANAGER
C:\USERS\JON\DESKTOP\HUDSON CAP\PHOTO SHEETS.DWG PLOT DATE 3/20/2020 2:08 PM JON SWAIM1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com
Photo One: View looking downstream at inlet of
original dual CMP culverts, Holly Hill Street crossing.
Culverts were removed and replaced with concrete
culverts and concrete headwall. No viable photos
were taken of culvert outlets due to dense
vegetation.
Photo Two: View looking downstream at inlet of
original dual CMP culverts, Hickman Avenue
crossing. Culverts and headwall were removed and
replaced with concrete culverts and concrete
headwall.
Photo Three: View looking at original condition of left
bank UT Gunpowder Creek. Mature tree root system
visible running horizontally within bank. Excavation
will be avoided in this area to prevent root damage
resulting in potential erosion and riparian tree
mortality.
Photo Four: View looking upstream at outlet of
original dual CMP culverts, Hickman Avenue.
Culverts and headwall were removed and replaced
with concrete culverts and concrete headwall.
PHOTOSHEET 2 A-9
FIGURE
CALDWELL COUNTY, NORTH CAROLINA
HOLLY HILL ST AND HICKMAN AVE
TOWN OF HUDSON
STORM DRAIN COMPLIANCE3/20/20
DATE
19.01412
PROJECT #
MO
PROJECT MANAGER
C:\USERS\JON\DESKTOP\HUDSON CAP\PHOTO SHEETS.DWG PLOT DATE 3/20/2020 2:19 PM JON SWAIM1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com
Photo Five: View looking downstream at outlet of
original dual CMP culverts, Hickman Avenue.
Culverts and headwall were removed and replaced
with concrete culverts and concrete headwall.
Photo Six: View looking downstream at new inlet of
dual concrete culverts, Holly Hill crossing.
Concrete can be seen between culverts in stream
channel. Concrete and rip rap containing concrete
will be removed.
Photo Seven: View looking at outlet end of newly
installed concrete culverts and headwall, Holly Hill
crossing. Proposed boulder cross vane to be
installed in this area.
Photo Eight: View looking downstream at outlet end
of newly installed concrete culverts and headwall,
Holly Hill crossing. Proposed boulder cross vane to
be installed in this area.
PHOTOSHEET 3 A-10
FIGURE
CALDWELL COUNTY, NORTH CAROLINA
HOLLY HILL ST AND HICKMAN AVE
TOWN OF HUDSON
STORM DRAIN COMPLIANCE3/20/20
DATE
19.01412
PROJECT #
MO
PROJECT MANAGER
C:\USERS\JON\DESKTOP\HUDSON CAP\PHOTO SHEETS.DWG PLOT DATE 3/20/2020 2:50 PM JON SWAIM1013 State Farm Road
Boone, NC 28607
828.386.1920
NC Firm License # C-0459
mcgillassociates.com
Photo Nine: View looking at left bank inlet side,
Hickman Avenue. Rip rap on streambank will be
removed, coir log toe protection, matting, native
seeding and live stakes installed in this area.
Photo Ten: View looking at right bank inlet side,
Hickman Avenue. Streambank will be sloped back
by hand, matting, native seeding and live stakes
installed in this area.
Photo Eleven: View looking downstream at right
bank outlet end, Hickman Avenue. Rip rap on right
streambank will be removed, coir log toe protection,
matting, native seeding and live stakes installed in
this area. Excavation will be avoided to preserve
mature trees and root systems within bank.
Photo Twelve: View looking upstream from culvert
outlet, Hickman Avenue during construction.
Geotextile fabric being installed prior to rip rap
installaion.