HomeMy WebLinkAbout20170239 Ver 1_BMP_Manual_20180325BEST MANAGEMENT PRACTICES
FOR
CONSTRVCTION
AND
MA1 NTENANCE
ACTIVITI ES
NORTH CAROLINA DEPARTMENT
OF TRANSPORTATION
August 2003
BEST MANAGEMENT PRACT/CES FOR CONSTRUCTION AND MAINTENANCE ACTIVITIES
TABLE OF CONTENTS
1.0 BACKGROUND INFORMATION ................................................................................ 1
1.1 INTRODUCTION .................................................................................................................................................. 2
1.2 PURPOSE OF MANUAL ...................................................................................................................................... 3
2.0 PROJECT PLANNING AND PRECONSTRUCTION .................................................. 7
2.1 PLANNING .............................................................................................................................................................8
2.2 PRECONSTRUCTION ......................................................................................................................................... 9
3.0 GENERAL PROJECT CONSTRUCTION PRACTICES/ OPERATIONS .................. 11
3.1 PROJECT MONITORING ................................................................................................................................. 12
3.2 EROSION AND SEDIMENTATION CONTROL ............................................................................................ 12
3.3 MANAGING THE WATERCOURSE ............................................................................................................... 13
3.4
3.5
3.6
3.7
3.8
MANAGING THE BUFFER AREAS ................................................................................................................ 14
MANAGING THE WORK AREA ..................................................................................................................... 16
MANAGING THE SPOIL .................................................................................................................................. 17
GROUND STABILIZATION ............................................................................................................................. 18
SITECLEAN-UP ................................................................................................................................................. 20
4.0 SPECIFIC CONSTRUCTION PRACTICES/ OPERATIONS ..................................... 21
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
PIPE/CULVERT EXTENSIONS ........................................................................................................................ 22
PIPE/CULVERT INSTALLATION ................................................................................................................... 26
SLOPE REPAIRS ADJACENT TO JURISDICTIONAL WATERS ............................................................. 33
HEADWALL INSTALLATION ......................................................................................................................... 36
OUTLET MAINTENANCE ................................................................................................................................ 39
BRIDGEDEMOLiTION .................................................................................................................................... 41
BRIDGECONSTRUCTION ............................................................................................................................... 44
CHANNELRELOCATION ................................................................................................................................ 47
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Pagei
Table of Contents
5.0 OPERATION BEST MANAGEMENT PRACTICES .................................................. 51
5.1 EROSION CONTROL ........................................................................................................................................ 52
5.1.1 Temporary Silt Fence ......................................................................................................................................... 53
5.1.2 Special Sediment Control Fence ........................................................................................................................ 55
5.1.3 Temporary Silt Ditch .......................................................................................................................................... 56
5.1.4 Temporary Rock Silt Check Type «A> . .............................................................................................................. 58
5.1.5 Temporary Rock Sediment Dam Type «B> ......................................................................................................... 60
5.2 FLOW DIVERSION ............................................................................................................................................ 62
5.2.1 Bypass Pumping ................................................................................................................................................. 63
5.2.2 Suspended Bypass Pipe ...................................................................................................................................... 66
5.2.3 Piped Diversion .................................................................................................................................................. 69
5.2.4 Fabric Lined Diversion Channel ........................................................................................................................ 71
5.2.5 Turbidity Curtain ............................................................................................................................................... 74
5.3 IMPERVIOUS DIKES ......................................................................................................................................... 76
5.3.1 Stone with Impervious Fabric ............................................................................................................................ 77
5.3.2 Sand Bags .......................................................................................................................................................... 79
53.3 Prefabricated Dams ............................................................................................................................................ 81
53.4 Sheet Piles .......................................................................................................................................................... 83
5.4 DEWATERING ....................................................................................................................................................85
5.4.1 Stilling Basin for Pumped Effluent .................................................................................................................... 86
5.42 Special Stilling Basin (Silt Bag) ........................................................................................................................ 88
5.5 TEMPORARY STREAM CROSSINGS ............................................................................................................ 90
5.5.1 Temporary Fording ............................................................................................................................................ 91
5.5.2 Temporary Piped Crossing ................................................................................................................................. 93
5.5.3 Temporary Access Bridge .................................................................................................................................. 95
5.6 GROUND STABILIZATION ............................................................................................................................. 98
5.6.1 Temporary Seeding and Mulching ..................................................................................................................... 99
5.6.2 Permanent Seeding and Mulching ................................................................................................................... 101
5.6.3 Erosion Control Blankets ................................................................................................................................. 103
5.6.4 Riprap Slope Protection ................................................................................................................................... 105
5.6.5 Riprap Outlet Protection .................................................................................................................................. 107
5.7 MAINTAINING NORMAL FLOW ................................................................................................................. 109
5.7.1 Sills .................................................................................................................................................................. 110
5.72 Cross Vane Rock Weir ..................................................................................................................................... 111
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Pageii
Table of Contents
APPENDICES
ACRONYMS ......................................................................................................APPENDIX A
TERMS AND DEFINITIONS ..............................................................................APPENDIX B
CONTACT LIST .................................................................................................APPENDIX C
REGULATIONS, 2003 .......................................................................................APPENDIX D
ENVIRONMENTAL PERMITS & CERTIFICATIONS, 2003 ... ...........................APPENDIX E
PREDICTABLE PERMIT CONDITIONS ...................................................APPENDIX F
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page iii
1. 0 BA CKGROUND INFORMA TION
1.1 Introduction
1.2 Purpose of Manual
1.3 Ethics Policy
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 1
Section 1.0 —Background Information
1.1 INTRODUCTION
Improper construction and maintenance practices can have
significant impacts on water quality, stream ecology and
aquatic habitat. The health of these aquatic systems impacts
many aspects of life in North Carolina including fishing, travel
and tourism, water-based recreation, drinking water supplies
and aesthetics. Healthy stream ecology and aquatic habitat
are necessary to support a healthy recreational and
commercial fishing stock. Good water quality is key to
providing clean and affordable drinking water supplies and
maintaining attractive water bodies that invite recreational
use.
Much of North Carolina's economy is supported by aquatic
trades and tourism and many of North Carolina's citizens
enjoy activities on or around the numerous streams, lakes
and estuaries the state has to offer. By managing North
Carolina Department of Transportation's (NCDOT) operation
and maintenance activities to minimize adverse water quality
impacts, we all help maintain the outstanding quality of life
and stewardship that takes place in North Carolina.
NCDOT can best manage its water quality impacts by
performing work in and around bodies of water with the
utmost care and by using Best Management Practices
(BMPs) that focus on minimizing sediment loss from a
project. Sediment transport is a natural stream function.
However, excess sediment is the number one pollutant in
streams across the state of North Carolina and its impacts
are often seen far downstream. When sediment enters a
stream it can have a number of effects on the water body. It
may cause turbidity, or clouding of the water, which reduces
light penetration through the water column. Decreased light
penetration can affect plant life and the levels of oxygen in
the water, which in turn affects aquatic life that obtain oxygen
from the water. Sediment particles suspended in the water
column also add erosive force to a stream, much like a piece
of sandpaper, and can contribute to accelerated bank erosion
and wash away the streambeds. Sediment settles to the
bottom of water bodies and smothers the insects, microbes
and plants that support healthy populations of fish and other
aquatic animals. Sediment can also serve as the transport
mechanism for many other pollutants that adhere to sediment
particles, such as nutrients, bacteria, pesticides, and organic
matter which have their own adverse affects on the water
body.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 2
Section 1.0 —Background Information
1.2 PURPOSE OF MANUAL
NCDOT is responsible for managing new roadway
construction and operating and maintaining over 76,000 miles
of existing roadway throughout the state. This manual is
designed for employees and contractors to construct, and
maintain the NCDOT roadway systems while minimizing
adverse impacts on the water resources of the State.
This manual assumes that the proper permits have
been obtained and notifications sent before any
work begins in the jurisdictional areas.
This manual includes the necessary information for the
Department to perform essential activities while minimize
their impacts on jurisdictional areas during normal
construction, maintenance, and emergency repair situations.
Activities in and around streams, lakes and estuaries are
regulated by a number of different programs and anyone
perForming work in these areas should have some idea of the
magnitude of regulations governing their activities. This
manual provides guidance on a number of BMPs consistent
with existing regulatory programs that should be utilized when
working within or adjacent to jurisdictional areas.
The Project Planning and Preconstruction section describes
the actions that should be performed prior to any construction
or maintenance activities. The Construction Supervisor is not
responsible for performing these actions but should question
the Lead Engineer and/or Division Environmental Officer
(DEO) if it is unclear that these activities have been
completed. The Construction Supervisor should ensure that
all permit conditions are followed and that no work is
performed outside of areas shown as impacted in permit
drawings or plans.
The General Project Construction Practices/Operations
section provides an overview and general guidance for field
personnel/contractor that should be applied to all projects and
activities within or adjacent to jurisdictional areas. Specific
conditions that shall be followed on all projects are
highlighted.
The overview and general process for all projects is followed
by specific guidance in the Specific Construction
Practices/Operations section. Specific construction practices
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 3
Section 1.0 —Background Information
are identified and guidance provided so the project can be
completed in an environmentally responsible manner. This
section also identifies appropriate BMPs, provides a general
overview of the construction sequence as it relates to
protecting jurisdictional areas, and highlights specific
conditions that must be followed in order to be in compliance
with NCDOT Environmental Stewardship Policy, as well as
State and Federal regulations.
The last section of the manual includes activity-specific
information for each individual BMP such as where the
practice is and is not applicable, construction standards,
maintenance requirements, and typical problems. Some of
the BMPs identify the appropriate NCDOT standard and
specification for proper construction. While other BMPs have
detailed construction specifications and installation
procedures, the intent is to not duplicate existing standards
and provide standards where none exist.
The overall goal of this manual is to provide guidance to
construction crews when working within and adjacent to
jurisdictional areas. At the same time providing flexibility to
the crews to choose which method is suitable for each given
situation.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 4
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August2003
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BMPs for Construction and Maintenance Activities
Page 5
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North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 6
2.0 PROJECT PLANNING AND
PRECONS TR UC TION
This section provides guidance to Lead Engineers, Division
Environmental Officers, and Contractors with respect to
planning and preconstruction activities on projects in or
adjacent to jurisdictional waters. It is assumed that the
proper permits have been obtained and notifications sent
before any work begins in the jurisdictional areas.
2.1 Planning
2.2 Preconstruction
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 7
Section 2.0 - Project Planning and
Preconstruction
2.1 PLANNING
• All projects shall have obtained the proper permits
or authorization from the USACE, DWQ, DCM,
CAMA, DLR-LQS, DWR, US Fish and Wildlife
Service, and/or NC Wildlife Resources
Commission prior to construction.
For projects designed, bid, and awarded as part of
the NCDOT Transportation Improvement Project
process, the Lead Engineer and/or DEO will
attend the pre-construction meeting or arrange a
regulatory meeting to discuss permit conditions for
the specific project if necessary.
For NCDOT Division projects, the DEO shall
confirm whether the project is located on a
jurisdictional stream and delineate other
environmentally sensitive areas such as wetlands,
stream buffers, high quality waters, trout waters,
Areas of Environmental Concern (AECs), etc.
Final jurisdictional determination authority is with
USACE.
For NCDOT Division projects, the Lead Engineer
and DEO shall determine if the project requires a
Pre-Construction Notification to utilize a general
404 permit, a 401 certification and/or an
authorization for buffer zone impacts, or other
applicable permits prior to construction.
If necessary, the DEO will also determine the
potential for adverse impacts to known federally
protected species populations (listed in that
county by the Fish and Wildlife Service as shown
on the NC Natural Heritage database) by
conducting an onsite survey for those species and
their suitable habitats.
• If necessary, the Lead Engineer or DEO will
consult with the State Historic Preservation Office
(SHPO).
• For NCDOT Division projects where CAMA AEC's
exist in the project area, a pre-application meeting
should be scheduled with the Division of Coastal
Management (DCM) field representative. The
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 8
Section 2.0 - Project Planning and
Preconstruction
Lead Engineer or DEO shall schedule this
meeting well in advance of letting or construction.
• No demolition, construction, filling, excavation, or
other ground disturbance should occur in a CAMA
AEC without specific approval by DCM.
• The Lead Engineer, DEO, and Contractor shall be
well versed in the guidance provided in Sections
3.0, 4.0 and 5.0 of this manual prior to undertaking
the design and construction of a project in the
vicinity of jurisdictional waters.
• All projects shall have an erosion and
sedimentation control plan in compliance with
current NCDOT practices.
• Roadside Field Operation Engineer (RFOE) must
review and approve the erosion and
sedimentation control plan for trout waters before
submission to District Wildlife Resources
Commission Fisheries Biologist.
• All timber bridge deck removal, bridge demolition,
and bridge construction projects shall have a
detailed plan of these activities submitted and
approved by the Resident Engineer.
• In general the Divisions should consult the
NCDOT Hydraulics Unit for proper sizing of any
pipes or culverts > 48" diameter.
• All appropriate BMPs for the given site conditions
shall be followed by field personnel.
• The Construction Supervisor or Lead Engineer
shall ensure issues such as vertical clearance,
horizontal clearance, and access are addressed.
2.2 PRECONSTRUCTION
• The Construction Supervisor shall have a copy of all
permits (including permit drawings showing all
jurisdictional areas) on-site during construction or all
jurisdictional areas should be clearly identified or marked
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 9
Section 2.0 - Project Planning and
Preconstruction
on the ground.
• The Lead Engineer shall check the project plans for
consistency with the permit drawings and report any
discrepancies to the DEO.
• Any questions regarding general and special
permit conditions should be discussed with the
DEO and RFOE.
• Any impacts to jurisdictional areas for
waste/borrow activities other than shown on the
permit drawings and project plans are prohibited.
• The Contractor shall have submitted and received
an approved Reclamation Plan that has been
signed off by the RFOE.
• For waste/borrow areas, the Contractor is
responsible to identify jurisdictional surFace
waters, wetlands, AECs (CAMA), and address
federally listed threatened and endangered
species issues per NCDOT Standard Specification
802-2.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 10
3. 0 GENERA L PROJEC T
CONSTRUCTION PRACTICES/
OPERA TIONS
This section provides general guidance for field personnel
working on projects in or adjacent to jurisdictional waters. These
guidelines are generic and should be universally applied to all
projects. It is assumed that the proper permits have been
obtained and notifications sent before any work begins in the
jurisdictional areas.
3.1 Project Monitoring
3.2 Erosion Control
3.3
3.4
3.5
3.6
3.8
3.9
North Carolina Department of Transportation
August2003
Managing the Watercourse
Managing the Riparian Buffer
Managing the Work Area
Managing Spoil
Ground Stabilization
Site Cleanup
BMPs for Construction and Maintenance Activities
Page 11
Section 3.0 Genera/ Project Consfruction
Pra ctices/Opera tions
3.1 PROJECT MONITORING
The Roadside Field Operations Engineer (RFOE) and
the Division Environmental Officer (DEO) monitors
construction activities for adherence to the Construction
and Maintenance Manual and any permit conditions.
Periodic field review will be made to ensure compliance
with erosion and sedimentation control laws, permit
conditions, buffer rules, and other environmental
considerations.
• The RFOE, through the Chief Engineer's office, has the
authority to require correction of erosion and
sedimentation control problems on NCDOT projects
through the Immediate Corrective Action (ICA) process.
3.2 EROSION AND SEDIMENTATION
CONTROL
Erosion and sedimentation control consists of ineasures
taken to prevent sediment from leaving the job site. Structural
controls reduce erosion from disturbed areas. Sediment
controls intercept and treat runoff before it is discharged from
the project. Velocity controls also help reduce velocity,
reduce the erosive force of runoff, and cause suspended
particulates to settle out.
Figure 1. Typical Perimeter Erosion Controls
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 12
Section 3.0 General Project Construction
Practices/Operations
Several specific methods of erosion and sediment control are
provided in this manual (see Section 5.1). However, the
following general measures should be employed as
appropriate:
• Install erosion and sedimentation control measures prior
to any land disturbing activity, including clearing and
grubbing.
• Sedimentation control measures are installed both within
the work area and on the outside limits of the work area
to control runoff from disturbed areas before it leaves the
site.
• Remove erosion and sedimentation controls measures
after graded project area is complete and stable.
3.3 MANAGING THE WATERCOURSE
The work area must be isolated from the normal flow of a
stream and the flow in the stream that occurs during minor
rainfall events. When the stream must be diverted on a
project, the watercourse should be managed to minimize
adverse impacts to the jurisdictional waters.
All projects should minimize the time that the watercourse will
be diverted. Several specific methods of diverting a
watercourse are provided in this manual (see Section 5.2).
However, the following general measures should be
employed on all projects as appropriate:
The stream's normal flow and flow during minor rainfall
events shall be maintained near normal downstream flow
conditions without mixing with untreated water from the
work area. This can be accomplished by diverting the
stream around or through the work area.
Where the construction time is anticipated to be less than
one day and no normal flow occurs in the channel, the
watercourse can be managed by keeping equipment and
materials from entering the stream channel and
maintaining appropriate erosion and sedimentation
controls. Since these steam channels are intermittent, the
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 13
Section 3.0 Genera/ Project Consfruction
Pra ctices/Opera tions
timing of construction should be during times of no stream
flow.
• Where the construction time is anticipated to be less than
one day and little or no base flow occurs in the channel,
an impervious dike may be utilized to create an
impoundment upstream of the work area.
Figure 2. Water Course Diversion
• The watercourse shall be managed to minimize any
flooding of the work area.
3.4 MANAGING THE BUFFER AREAS
Buffers are legally protected areas along jurisdictional waters
such as streams, lakes, ponds and estuaries. Buffer
requirements may be applied throughout a regional area,
such as a river basin, watershed or AEC, and may vary from
region to region.
It is important to be familiar with the requirements that apply
in your project area. The following general buffer
requirements provide initial guidance:
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 14
Section 3.0 Genera/ Project Consfruction
Pra ctices/Opera tions
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• Prior to 2003, state riparian buffer requirements were in
place in the Neuse, Tar-Pamlico, and Catawba River
Basins and in the Randleman Reservoir watershed as
part of the Water Supply Watershed Rules. Be aware
that buffer programs may have been added in other river
basins or watersheds since 2003.
• Cities and counties may have specific local riparian buffer
requirements. Be familiar with the specific buffer rules
that apply in the work area. Consult with the DEO to
determine if/what buffer rules are in effect in the project
area.
• Riparian buffer requirements may also apply in coastal
shoreline AEC's.
• Typically, the riparian buffer is a 50-foot wide vegetative
strip along each side of a jurisdictional stream measured
from the top of bank or the mean high water line. The
riparian buffer typically cannot be disturbed unless
specific conditions are satisfied.
• Trout waters must have a 25-foot minimum width of
undisturbed buffer zone. When temporary and minimal
disturbance is permitted, it shall be limited to a maximum
of 10% of the total length of the buffer zone within the
tract to be disturbed.
• Existing drainage ditches and roadside ditches are
typically exempt from the buffer rules provided that they
are managed to minimize sediment, nutrients and other
pollution that enters jurisdictional waters. However, the
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 15
Section 3.0 General Project Construction
Practices/Operations
DEO should first determine whether a roadside ditch is a
modified natural stream or not.
• Existing drainage ditches may not be deepened beyond
original pre-construction depths.
• New ditches through a riparian buffer are typically not
allowed unless specific conditions are satisfied.
• Excavation of stream beds is prohibited.
• Consult DWQ on installation of sediment and erosion
control devices in zone 1, as needed.
3.5 MANAGING THE WORK AREA
For this manual, the work area consists of the area necessary
to perForm the construction or maintenance activity within or
adjacent to jurisdictional areas. They include but are not
limited to excavation and storage of material offsite in upland
disposal sites, construction, and the maneuvering of
equipment and manpower.
The following general measures should be employed on all
projects as appropriate:
• All land disturbing activities shall be confined to the work
area as shown in the permit drawings, including
equipment staging and access.
• The work area shall be isolated from jurisdictional
waters. The goal is to prevent the discharge of water
from the work area prior to treatment.
• All runoff from the work area shall drain through a
Sedimentation Control BMP or a Dewatering Device
BMP prior to entering jurisdictional waters.
• Intermediate Sedimentation Control BMPs may be
needed as work progresses and the work area changes
in size and elevation.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 16
Section 3.0 Genera/ Project Consfruction
Pra ctices/Opera tions
Figure 4— Managing the Work Area
BMPs shall be maintained throughout the life of the
project. Refer to Section 5.0 for proper maintenance of
specific BMPs.
• Multiple small work areas in lieu of one large work area
may be established to minimize the disturbance of
jurisdictional waters.
3.6 MANAGING THE SPOIL
Excavated material or spoil shall either be:
• Contained within the work area.
• Stockpiled near the work area and contained by an
appropriate Erosion and Sedimentation Control BMP.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Pagel7
Section 3.0 Genera/ Project Construction
Pra ctices/Opera tions
• Removed from the site and disposed of properly.
• Spoil material shall not be placed in wetlands, protected
riparian buffers, or other jurisdictional areas.
• Used for reestablishing groundcover.
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Figure 5. Typical Spoil Management
3.7 GROUND STABILIZATION
After completion of construction or land disturbing activities,
all disturbed areas must be stabilized to prevent future
erosion. Establishing a good vegetative cover helps protect
soil from the impact of raindrops and reduces the erosive
forces of runoff. Hard armor, such as riprap, helps protect
areas that cannot be stabilized with vegetation.
Several specific methods of ground stabilization are provided
in this manual (see Section 5.6). However, the following
general measures should be employed on all projects as
appropriate:
• When construction/repairs are complete, remove all
construction debris, includinq old concrete, asphalt, and
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 PagelB
Section 3.0 Genera/ Project Consfruction
Pra ctices/Opera tions
stockpiled material.
• Notify the seeding crews in advance when final grading is
to be performed.
• Dress and fine grade disturbed areas.
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Figure 6. Ground Stabilization
• Prepare an adequate seed bed. Wetland areas are to
planted with appropriate seed mixtures. Consult with
RFOE and DEO in your division to determine the
appropriate seed mixture.
• Maintain erosion control BMPs until vegetation is well
established.
• Do not apply fertilizer directly into streams.
• Temporary seeding shall be performed if the project is to
remain idle for longer than 15 working days. Working
days means days exclusive of Saturday and Sunday
during which weather conditions or soil conditions permit
land-disturbing activities to be undertaken.
• Do not spray straw tacking material into stream during
seeding operation.
• Disturbed areas in riparian buffers may need planting of
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Pagel9
Section 3.0 Genera/ Project Consfruction
Pra ctices/Opera tions
woody species, in addition to seeding.
3.8 SITE CLEAN-UP
Figure 7 — Site Clean-up
• Temporary fill shall not be placed within jurisdictional
waters and wetlands unless specifically identified in the
permit.
• When temporary fill is approved, it shall be completely
removed and the affected area restored to the pre-project
conditions upon completion of the construction activity.
• After establishment of the groundcover vegetation,
remove sedimentation control BMPs and restore the
ground to pre-project conditions and stabilize.
• Continue to spot seed and mulch exposed, erodible
areas.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 20
4. 0 SPECIFI C CONS TR UC TION
PRA C TI CES/ OPERA TIONS
This section provides detailed information on specific construction
practices/operations that are perFormed in or adjacent to
jurisdictional waters. Specific construction projects are identified
along with the steps that shall be taken to complete the project in
an environmentally responsible manner. It is assumed that the
proper permits have been obtained and notifications sent before
any work begins in the jurisdictional areas.
For each practice/operation, appropriate BMPs are identified and
specific conditions highlighted in order to be in compliance with
NCDOT, State, and Federal regulations.
4.1
4.2
Pipe/Culvert Extensions
Pipe/Culvert Installation
4.3 Slope Repairs Adjacent to Jurisdictional Waters
4.4 Headwalllnstallation
4.5 Outlet Maintenance
4.6
4.7
4.8
North Carolina Department of Transportation
August2003
Bridge Demolition
Bridge Construction
Channel Relocation
BMPs for Construction and Maintenance Activities
Page 21
Erosion Control
Managing Watercourse
4.1 - Pipe/Culvert Extensions
4.1 PIPE/CULVERT EXTENSIONS
This section describes the steps to take when performing a
pipe extension on a jurisdictional stream.
1. Prior to installing Erosion Control, identify permit
conditions and impact area limits. Contact the Division
Environmental Officer (DEO) for information on permit
drawings or jurisdictional areas.
2. Install temporary silt fence or silt ditch to treat runoff from
the work area or isolate the work area from the
jurisdictional areas (See Section 5.1)
3. Install Temporary Rock Silt Check Type "A" or Temporary
Sediment Dam Type "B" in ditch lines to contain sediment
prior to discharge into the watercourse (See Section 5.1)
4. Streamflow diversion is typically utilized to isolate the
work area using the bypass pumping or suspended
bypass pipe (See Section 5.2).
• In CAMA AECs, the type of flow diversion is
identified in the permit.
5. Utilize a temporary stream crossing (See Section 5.5)
when the stream must be crossed in an area that will not
be permanently replaced by the pipe extension.
• In CAMA AECs, the type of temporary stream
crossing is identified in the permit
Managing Work Area 6. Dewatering devices such as silt bags, stilling basins or
Temporary Rock Sediment Dam Type "B" should be used
to manage water from the work area prior to discharge
(see Sections 5.4 and 5.1).
• In CAMA AECs, the type of dewafering device
is identified in the permit
7. Install the pipe/culvert per the NCDOT standards and
specifications.
• Foundation material shall be confined to the
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 22
4.1 - Pipe/Culvert Extensions
pipe extension area and shall not be placed in
the existing stream channel outside the pipe
extension area.
• Excavation of stream channel shall not exceed
10 feet on either end of the new pipe%ulvert.
However, DEO should ensure that all work
falls within the threshold of the riparian buffer
rule or other rule.
• No live or fresh concrete shall come into
contact with jurisdictional waters until the
concrete has cured.
,
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Figure 8. Culvert Construction
8. Install the riprap slope and outlet protection where
required (See Section 5.6).
• Placement of riprap within jurisdictional
waters must be the minimum necessary fo
protect or ensure the safety of the slopes.
• Minimal riprap should be used to line stream
channel and should not impede aquafic
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 23
4.1 - Pipe/Culvert Extensions
organism passage.
• Riprap shall consist of c/ean rock or masonry
material free of debris or pollufants.
• If the streambed is subject to high velocity at
the outlet of the culvert, engineering outlet
protection measures, such as energy
dissipaters should be insfalled a minimum of
1.0 foot below fhe existing streambed.
9. Remove flow diversion and allow the stream to flow
through the new pipe/culvert extension.
• The impervious dike shall be completely
removed from the existing stream and the
affected areas restored to the pre-projecf
conditions.
10. Begin backfill operations. Intermediate erosion and
sediment control BMPs shall be installed prior to the
backfill operation to provide containment between the
work area and the watercourse.
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North Carolina Department of Transportation
August2003
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Figure 9. Completed Culvert Extension
BMPs for Construction and Maintenance Activities
Page 24
Ground Stabilization
Site Cleanup
4.1 - Pipe/Culvert Extensions
11. Upon completion of backfill operations, prepare slopes
and other disturbed areas and stabilize (See Section 5.6).
12. Maintain erosion and sedimentation control measures
until groundcover or vegetation is well established.
13. Upon establishment of vegetation, remove any remaining
erosion and sedimentation control BMPs and stabilize
disturbed areas.
• Within jurisdictional waters and wetlands all
temporarily disturbed areas shall be restored to the
pre-project conditions and planted with appropriate
plant species.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 25
4.2 - Pipe/Culvert Installation
4.2 PIPE/CULVERT INSTALLATION
This section describes the steps to take when an existing pipe or
culvert is being constructed or replaced on a jurisdictional stream.
1. Prior to installing Erosion Control, identify permit conditions
and impact area limits. Contact the Division Environmental
Officer (DEO) for information on permit drawings or
jurisdictional areas.
Erosion Control 2. Install temporary silt fence or silt ditch to treat runoff from the
work area or isolate the work area from the jurisdictional
areas, such as wetlands or riparian buffers (See Section 5.1).
3. Install Temporary Rock Silt Check Type "A" or Temporary
Sediment Dam Type "B" in ditch lines to contain sediment
prior to discharge into the watercourse (See Section 5.1).
Do not install Temporary Rock Silt Check Type
"A" or Temporary Sediment Dam Type "B" in
stream channel
Figure 10. Pipe Repair/Replacement
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 26
Managing the Water
Course
4.2 - Pipe/Culvert Installation
4. On larger streams, flow diversion may be used to isolate the
work area using bypass pumping, piped diversion or fabric-
lined channel (See Section 5.2). On smaller streams, or at low
flow conditions, an impervious dike may be used to
temporarily dewater the work area within the stream channel
(See Section 5.3).
• All temporary in-stream structures must be
insfalled with geotextile fabric beneath them, and
removed in their entirety immediately upon
completion of in-stream work
• In CAMA-AECs, the type of flow diversion is
identified in the permit.
5. Temporary stream crossings may be utilized in order to
provide equipment access, if underlain by geotextile fabric, so
that the riprap may be entirely removed (See Section 5.5).
• Confirm that the temporary stream crossing is
shown in the permit drawings as an approved
temporary impact.
• In CAMA-AECs, the type of temporary stream
crossing is identified in the permit.
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Figure 11
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Pipe/Culvert Foundation Installation
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 27
Managing the Work
Area
4.2 - Pipe/Culvert Installation
6. Dewatering devices are typically needed to keep the work
area dry (see Section 5.4). The permit conditions and the
amount of available space and length of pipe replacement or
project limits will determine the type of dewatering device to
be used. Every effort should be made to minimize the extent
of the area to be dewatered and the length of time the site is
dewatered.
• In CAMA-AECs, the type of dewatering device is
identified in the CAMA permit.
7. Install the pipe/culvert per the NCDOT standards and
specifications, and any specified permit conditions. Note that
pipes and culverts shall be buried a minimum depth below the
existing streambed, as defined below, in order to allow for
aquatic organism passage during low flow conditions.
Variance may be obtained by the DEO to allow for deviations
in pipe burial depths due to bedrock, steep gradients in the
stream channel, existing headcutting, potential for drainage of
upstream wetlands, or other concerns.
Figure 12. Pipe/Culvert Installation
• Foundation material shall be confined to the
pipe%ulvert area and shall not be placed in the
existing stream channel outside of the permifted
impact area.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 28
4.2 - Pipe/Culvert Installation
• Excavation of the stream channel shall not exceed
10 feet on either end of the new pipe or culvert
unless the stream is being relocated per Section
4.9, or if indicated in the permit.
• Within river basins subject to the Riparian Buffer
Ru/es, projects may be exempt if work in the
stream channel is limited to a total of 40 feet of
additional impact, including pipe extension.
• In CAMA AECs (within the twenty coasta/
counties), all pipes and culverts must be buried
one foot below the existing average streambed
elevation.
• In other parts of the state, pipes/culverts must be
buried as follows:
o Culverts 48-inches in diameter or greater shall be
buried one foot below the streambed elevation.
Average streambed elevation shall be measured
from multiple measurements taken outside of the
area of scour or road crossing disturbance,
outside of the ROW limits, if necessary.
o Culverts /ess than 48-inches shall be buried a
depth equal to 20% of the pipe%ulvert diameter,
such as the following examples. The hydraulic
conveyance of the culvert however should not be
compromised.
Examples:
� 36„ _ �„
• 30" = 6"
� 24„ - 5„
� 18„ _ 4„
8. Stream pattern, dimension and profile shall be maintained
by pipe/culvert installation.
• A 4-foot diameter pipe%ulvert installed in a 2-foot
wide stream may require baffles in order to
maintain aquatic organism passage (AOP) during
low flow conditions.
• Pipe size should at least match stream width
wherever possible, but a 2-foot wide culvert
installed in a 4-foot wide stream may also need
baffles to reduce velocities.
• Two 48 inch pipes installed in a 10-foot wide
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 29
4.2 - Pipe/Culvert Installation
stream would require that one pipe be installed at
a lower elevation, and in alignment with the low
flow stream channel elevation, so that AOP is
mainfained during low f/ow condifions.
• The low flow pipe should be aligned with the
deepest part of the stream channel, so that flow is
maintained during low flow conditions.
• No "live" or fresh concrete shall come into contact
with jurisdictional waters until the concrete has
cured.
Figure 13. Pipe/Culvert Outlet Protection
9. Install the riprap shoulder slope and outlet protection on
upstream and downstream channels where indicated on
the permit drawings (See Section 5.6). Do not exceed
approved limits in the permit. Contact the DEO if the
permit or permit drawings are not clear.
• Riprap shall consist of c/ean rock or masonry
material free of debris or pollutants (such as
asphalt).
• Outlet profection shou/d be countersunk at /east
one foot below the average stream bed elevation.
• P/acement of riprap within jurisdictional waters
must be the minimum necessary to protect or
ensure shoulder s/ope and streambank stability.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page30
Ground Stabilization
Site Cleanup
4.2 - Pipe/Culvert Installation
10. Remove temporary flow diversion or dewatering devices and
accumulated sediment before allowing stream flow to resume
through the new pipe or culvert.
• The impervious dike shall be completely removed
to pre-project conditions.
• Care should be taken to not disturb or destabilize
the undisturbed streambed during removal of
temporary devices.
11. Stream realignment can occur within approved permit impact
limits. Minimize sharp or acute angles in stream alignment
wherever possible. Stream channel pattern, dimension and
profile should be maintained similar to the upstream and
downstream stream reach.
12. Bioengineering techniques may be used to stabilize
streambanks where feasible.
13. Begin backfill operations. Intermediate erosion and
sedimentation control BMPs shall be installed prior to the
backfill operation to provide containment between the work
area and the watercourse.
14. If the pipe/culvert is part of a larger roadway project, enough
backfill should be placed to allow for the removal of the
temporary stream crossing. If no temporary stream crossing
is required then enough backfill should be placed to prevent a
washout during a minor storm event.
15. Upon completion of backfill operations, prepare slopes and
other disturbed areas and stabilize (See Section 5.6).
16. Maintain erosion and sedimentation control measures until
ground vegetation is well established.
17. Upon establishment of vegetation, remove remaining erosion
and sedimentation control BMPs, stabilize and reestablish
remaining disturbed areas to proper grade, such as buffers,
wetlands, and water.
• Within jurisdictional waters & wetlands all
temporarily disturbed areas shall be restored to
the pre-project conditions.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 31
4.2 - Pipe/Culvert Installation
;.
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'i ..� . • . w: . ; .. :� _ �_
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Figure 14. Completed Pipe/Culvert Installation
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page32
4.3 - Slope Repairs Adjacent
to Jurisdictional Waters
4.3 SLOPE REPAIRS ADJACENT TO
JURISDICTIONAL WATERS
This section describes the steps to take when channel bank
slopes, cut slopes, or fill slopes are repaired on or adjacent to
jurisdictional waters, including wetlands. The required
permits should be obtained or coordinated with the ACOE,
DWQ, or DCM before removing sediment from jurisdictional
waters.
1. Prior to installing Erosion Control, identify permit
conditions and impact area limits. Contact the Division
Environmental Officer (DEO) for information on permit
drawings or jurisdictional areas.
Erosion Control 2. Temporary silt fence or silt ditches are typically installed
along the toe of the slope to intercept runoff from the work
area (See Section 5.1).
Managing the Water
Course
3. Install Temporary Rock Silt Check Type "A" or Temporary
Sediment Dam Type "B" in ditch lines to contain sediment
prior to discharge into jurisdictional waters (See Section
5.1).
4. Where normal flow occurs or for projects where potential
in-stream impacts may occur, an impervious dike or
turbidity curtain may be utilized to isolate the work area
from the stream flow. The curtain or impervious dike
should be placed adjacent to the work area and securely
anchored to isolate the work area from the stream. The
curtain shall not be used to cross or dam the stream flow.
(See Section 5.2 and 5.3).
5. If sediment from a slope failure must be removed from the
stream channel, the work area should be isolated from
the stream by installing an impervious dike or turbidity
curtain prior to beginning work.
• Removal of sediment resulting from fill s/ope
failure into a waterway is limited to the
minimum necessary to restore the waterway to
the pre-existing conditions.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 33
Managing the Work Area
Ground Stabilization
4.3 - S/ope Repairs Adjacent
to Jurisdictional Waters
6. Repair the slope.
• Riprap shall consist of c/ean rock or masonry
material free of debris or pollutants.
• Placement of riprap within jurisdictional
waters musf be the minimum necessary to
protect or ensure the safety of the slopes.
Riprap shall be limited to fhe toe of the s/ope
being sfabilized.
• No material shall be placed which impairs
surface water flow into any wetland area.
• No material shall be placed in a manner that
will be eroded or displaced by normal or
expected high flows.
7. Prepare slope and other disturbed areas and stabilize
(See Section 5.6).
Site Cleanup 8. Remove turbidity curtains or impervious dike after any
significant sediment accumulations have been removed
and turbidity of water has cleared.
• The impervious dike shall be completely
removed from the existing stream and the
affected areas restored to the pre-project
conditions.
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, Figure 15. Slope Repair
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 34
4.3 - Slope Repairs Adjacent
to Jurisdictional Waters
9. Upon establishment of vegetation, remove remaining
erosion and sedimentation control BMPs, stabilize, and
reestablish disturbed areas, such as buffers, wetlands,
and water.
• Within jurisdictional waters and wetlands all
temporarily disturbed areas shall be restored to
the pre-project conditions.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 35
Erosion Control
4.4 - Headwall Installation
4.4 HEADWALL INSTALLATION
This section describes the steps to take when a headwall is
being installed on an existing pipe or culvert on a jurisdictional
stream.
1. Prior to installing Erosion Control, identify permit
conditions and impact area limits. Contact the Division
Environmental Officer (DEO) for information on permit
drawings or jurisdictional areas.
2. Install temporary silt fence or silt ditch to contain sediment
in the work area (See Section 5.1).
3. Install Temporary Rock Silt Check Type "A" or Temporary
Sediment Dam Type "B" in ditch lines to contain sediment
prior to discharge into the watercourse (See Section 5.1).
Managing the 4. Typically, flow diversion is utilized to isolate the work
Watercourse area using the bypass pumping or suspended bypass
pipe (See Section 5.2).
• In CAMA-AECs, the type of f/ow diversion is
identified in the permit.
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Figure 16. Headwall BMP Installation
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page36
4.4 - Headwall Installation
Managing the Work Area 5. If needed, dewatering devices such as silt bags or
Temporary Rock Sediment Dam Type "B" should be used
to manage water from the work area prior to discharge
(See Section 5.4 and 5.1).
• In CAMA-AECs, the type of dewatering device
is identified in the permit.
6. Install the headwall per the NCDOT standards and
specifications.
• Foundation material shall be limited to the
headwall repair area and shall not be placed in
the existing stream channel outside the repair
area.
Excavation of stream channel shall not exceed
10 feet on either end of the pipe%ulvert.
However, DEO should insure that all work fa//s
within the threshold of the riparian buffer rule
or other rule.
• No live or fresh concrete shall come into
contact with jurisdictional waters until the
concrete has cured.
Figure 17. Prefabricated Headwall
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page37
Ground Stabilization
Site Cleanup
4.4 - Headwall Installation
7. Remove the flow diversion and allow the stream to flow
through the new pipe/culvert.
• The impervious dike sha// be completely
removed from the existing sfream and the
affected areas restored to the pre-project
conditions.
8. Place backfill around headwall. Install intermediate
erosion and sedimentation control BMPs where needed.
9. Prepare slope and other disturbed areas and stabilize
(See Section 5.6).
10. Upon establishment of vegetation, remove remaining
erosion and sedimentation control BMPs, stabilize, and
reestablish disturbed areas, such as buffers, wetlands, and
water.
�
• Within jurisdictional waters and wetlands, all
temporarily disturbed areas shall be restored to
the pre-project conditions
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Figure 18. Completed Headwall Installation
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page38
4.5 - Outlet Maintenance
4.5 OUTLET MAINTENANCE
This section describes the steps to take when outlet
protection is being installed on an existing pipe or culvert
located on a jurisdictional stream.
1. Prior to installing Erosion Control, identify permit
conditions and impact area limits. Contact the Division
Environmental Officer (DEO) for information on permit
drawings or jurisdictional areas.
Erosion Control 2. Minimize disturbed area needed for equipment access
and install appropriate erosion control device to contain
sediment in the work area (See Section 5.1).
Managing the 3. Typically, flow diversion is utilized to isolate the work area
Watercourse using the bypass pumping or suspended bypass pipe
(See Section 5.2).
• In CAMA-AECs, the type of flow diversion is
identified in the permit.
4. When the construction time is anticipated to be less than
one day and no normal flow occurs in the channel, the
watercourse can be managed by keeping equipment and
materials from entering the stream channel and
maintaining appropriate erosion and sedimentation
controls.
5. When the construction time is anticipated to be less than
one day and little or no base flow occurs in the channel,
an impervious dike may be utilized to create an
impoundment upstream of the work area. Since these
channels are intermittent, the timing of construction should
occur during times of no flow.
Managing the Work Area 6. If needed, dewatering devices such as silt bags, stilling
basins, or Temporary Rock Sediment Dam Type "B"
should be used to manage pumped water from the work
area prior to discharge (see Sections 5.4 and 5.1.)
• In CAMA-AECs, the type of dewatering device
is identified in the permit
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 39
Ground Stabilization
Site Cleanup
4.5 - Outlef Maintenance
7. Remove debris and sediment.
8. Install riprap slope and outlet protection where required.
• Outlet protection shall be buried a minimum of
one foot be/ow the streambed.
• Excavation of stream channel just for pipe
installation shall not exceed 10 feef on either
end of the pipe%ulvert However, DEO should
insure that all work falls within fhe thresho/d
of the riparian buffer rule or other rule.
9. Prepare slope and other disturbed areas and stabilize
(See Section 5.6).
10. Remove the flow diversion and allow the stream to flow
through the new pipe/culvert.
• The impervious dike shall be completely
removed from the existing stream and the
affected areas restored to the pre-project
conditions.
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Figure 19. Completed Outlet Maintenance
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 40
4.6 - Bridge Demolition
4.6 BRIDGE DEMOLITION
This section describes the steps to take when an existing
bridge is demolished over jurisdictional areas.
Erosion Control
Managing the
Watercourse
Managing the Work Area
North Carolina Department of Transportation
August2003
1. Prior to installing Erosion Control, identify permit
conditions and impact area limits. Contact the Division
Environmental Officer (DEO) for information on permit
drawings or jurisdictional areas.
2. Install temporary silt fences around each bridge
approach (See Section 5.1).
3. Install additional work area BMP measures when
required.
4. Install turbidity curtains when water surFace velocity
and depth are sufficient to move debris outside of
work area in sensitive water bodies (See Section 5.2).
5. Evaluate structure and site for best demolition method
that will create the least amount of debris and
sediment loss.
6. Locate all equipment on existing roadway or specially
constructed work pads
7. Transfer of fuel and vehicle maintenance should occur
in a containment site and away from surFace water
8. Collect and remove all loose debris and asphalt-
wearing surfaces from the roadway
9. Collect and remove all road surFace material before
removing bridge sections.
10. Remove bridge in the fewest number of sections as
possible to limit the amount of loose debris created.
• Always use non-shattering demolition
methods. If alternative methods such as
exp/osives are required, approval must be
granted from permitting agencies.
• Concrete bridge decks should be removed by
BMPs for Construction and Maintenance Activities
Page 41
Ground Stabilization
North Carolina Department of Transportation
August 2003
4.6-Bridge Demolition
sawing full depth or full span length in order to
remove deck and beam sections as one unit.
Remove any material that fa//s into the water
body. No bridge deck or substrucfure
components shall be dropped into the water.
lf this is not possib/e, such as the case of
concrete arch design, demolition should not
occur over more than one-half of the channel
width at a time.
If a CAMA permit is required, dropping any
component of a bridge into the water will not
be acceptable unless it is proven that there is
no feasible alternative. Such an activify would
require coordination with and approval from
DCM.
11. Remove loose debris and road surface material piles
from the work site promptiy to eliminate possible
scattering by wind and rain
12. Remove any debris and sediment resulting from the
bridge demolition at the end of each workday.
13. Inspect all equipment used near surface water for
possible leakage of liquid or semi-liquid fuels and
lubricants daily. Promptly remove any leaking
equipment from the area.
rigure �u. tsnctge uemouuon
14. Reevaluate temporary BMP measures that are
BMPs for Construction and Maintenance Activities
Page 42
Site Cleanup
North Carolina Department of Transportation
August2003
4.6-Bridge Demolition
required when the bridge demolition is complete.
15. Stabilize exposed stream banks with indigenous
vegetation or riprap if required.
• Riprap shall consist of clean rock or masonry
material free of debris or pollutants.
• No asphalt or concrete debris recycling
allowed in jurisdictional waters.
• Placement of riprap within jurisdictional
waters must be the minimum necessary to
protect or ensure the safety of the slopes.
Riprap shall be limited to the toe of the s/ope
being stabilized.
• No material is placed which impairs surface
water flow into any wetland area.
• No material is placed in a manner that will be
eroded by normal or expected high flows.
• Plant material should be installed during the
proper planting season and as soon as
possible to help stabilize the stream.
16. Remove inactive equipment from temporary
causeways or floodplain areas
17. Upon establishment of vegetation cover remove
remaining erosion and sediment control BMPs and
stabilize disturbed areas.
• Within jurisdictional waters and wetlands all
temporarily disturbed areas shall be restored
to the pre-project conditions
BMPs for Construction and Maintenance Activities
Page 43
Erosion Control
4.7 - Bridge Consfruction
4.7 BRIDGE CONSTRUCTION
This section describes the steps to take when a new bridge is
constructed.
1. Prior to installing Erosion Control, identify permit
conditions and impact area limits. Contact the Division
Environmental Officer (DEO) for information on permit
drawings or jurisdictional areas.
2. Install temporary silt fence, silt ditch, temporary rock silt
check type "A", or temporary sediment dam type "B" to
manage runoff from the work area required to install the
approach roadway approach fill (See Section 5.1).
3. Conduct approved clearing and grubbing necessary to
construct the roadway approach fill.
4. When stream banks are exposed due to clearing and
grubbing operations, banks should be stabilized with
indigenous vegetation or riprap.
• Riprap shall consist of clean rock or masonry
material free of debris or pollutants.
• Placement of riprap within jurisdictional waters
must be the minimum necessary to protect or
ensure the safety of the s/opes. Riprap shall
be limited to the toe of the slope being
stabilized.
• No material shall be placed which impairs
surface water flow into any wetland area.
• No material shall be placed in a manner that
will be displaced by normal or expected high
flows.
5. Temporarily seed and mulch roadway approaches and
maintain erosion control measures (See Section 5.6).
6. Install and or relocated erosion control measures to
manage runoff from the work area required for bridge
construction.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 44
Managing the
Watercourse
Managing the Work Area
4.7-Bridge Construction
7. Install turbidity curtain when water surface velocity and
depth are sufficient to move debris downstream outside of
work area in sensitive water bodies (See Section 5.2).
8. At the end of each workday, remove any debris or
sediment deposited outside of the work area as a result of
the bridge construction.
Figure 21 — Bridge Construction within Wetlands
9. Evaluate proposed bridge structure and site for best
construction methods that will minimize erosion potential
and construction debris. Steps for sequencing are
required on work plan.
10. Store construction material and equipment within the
construction limits of the project and away from flood
prone areas. No equipment should be stored in wetlands,
surFace waters, or protected riparian buffers.
11. Transfer of fuel and vehicle maintenance should occur in
a fuel containment area which is at least 50 feet away
from any surface water.
12. Locate all equipment on existing roadways or specially
constructed work pads.
13. Inspect and repair equipment for possible leakage of
liquid or semi-liquid fuels and lubricants. Promptly
remove any leaking equipment from the area.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 45
Ground Stabilization
Site Cleanup
4.7-Bridge Construction
14. Contain fresh concrete in wood or plastic forms and
properly clean-out areas so that no seepage occurs into
the adjacent water body, especially with the pouring of
foundation work.
• No live or fresh concrete shall come into contact
with jurisdictional waters until the concrete has
cured.
15. Install any scour protection measures in accordance with
permit conditions.
16. Maintain and adjust erosion and sedimentation control
measures as needed during all construction phases of the
project
Figure 22. Completed Bridge Construction
17. Remove inactive equipment from temporary causeway or
floodplain areas.
18. Dispose of construction debris and stockpiles of erodible
material properly and stabilize the site with sufficient
ground cover that will restrain erosion.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 46
Erosion Control
4.8 - Channel Re/ocation
4.8 CHANNEL RELOCATION
This section describes the steps to take when an existing
stream or channel is being relocated.
1. Prior to installing Erosion Control, identify permit
conditions and impact area limits. Contact the Division
Environmental Officer (DEO) for information on permit
drawings or jurisdictional areas.
2. Install temporary silt fence, silt ditch, temporary rock silt
check type "A", or temporary sediment dam type "B" to
treat runoff from the work area (See Section 5.1).
3. Typical channel relocation projects require erosion control
measures to be added and removed throughout
construction to prevent sediment and debris from
reaching the active stream.
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Figure 23. Stream Channel Relocation
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 47
Managing the
Watercourse
Managing the Work Area
4.8 - Channel Re/ocation
4. The existing stream shall be maintained as much as
practical while the relocated channel section is
constructed
5. Typically flow diversion is utilized to isolate the work area
using a fabric-lined diversion channel (See Section 5.2)
when the existing stream cannot be maintained.
• The existing stream shall not be diverted
during fish migration periods.
6. The existing stream flow shall only be diverted into either
a stable temporary flow diversion channel or a completed
and stabilized relocated channel reach.
7. Channel relocation projects typically include inactive and
active work areas to minimize the amount of exposed soil
at any given time.
8. Inactive work areas shall be stabilized by seed and mulch
temporarily, such that the work perFormed will not be
displaced in the event the area is inundated during a
storm event. (See Section 5.6).
9. Active areas shall be temporarily stabilized prior to an
anticipated precipitation event to prevent the work
performed from being displaced in the event the active
work area is inundated.
Figure 24. Completed Stream Channel Relocation
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 48
4.8 - Channel Relocation
10. Riprap shall only be placed when specifically shown on
the plans.
• Riprap shall consist of clean rock or masonry
material free of debris or pollutants.
• No material shall be placed which impairs
surface water flow into any wetland area.
• No material shall be placed in a manner that
will be eroded by normal or expected high
flows.
11. The stream dimensions and depth shown on the plans
are critical to the proper function of the channel
relocation. Notify the Resident Engineer and/or
regulatory agencies immediately if these dimensions
cannot be maintained.
Ground Stabilization 12. The relocated channel and surrounding area shall be
properly stabilized prior to receiving the normal stream
flow. It is important that vegetative plantings occurs at
the proper time of the year and as soon as possible to
help stabilize the stream.
Site Cleanup
13. Remove the flow diversion, if necessary, and allow the
stream to flow through the new channel.
• The impervious dike shall be completely
removed from the existing stream and the
affected areas restored to the pre-project
conditions
14. Remove all temporary erosion control measures and
properly dispose of excess spoil in upland disposal area
which require field confirmation/verification by DEO.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 49
THIS PAGE WAS INTENTIONALLY LEFT BLANK
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 50
5. 0 OPERA TION BEST MANA GEMENT
PRA C TI CES
Best Management Practices, or BMPs, include the host of tools
that are applied to a project to prevent pollutants from entering
jurisdictional waters and to minimize any pollutant loading. These
tools include structural and non-structural measures. In some
cases, a BMP is a structure that is installed on the site and in
other cases it is the way in which a project is managed or, more
typically, a combination of both. BMPs in this manual are
targeted at reducing the impact to jurisdictional waters by
roadway construction and/or maintenance activities. It is
assumed that the proper permits have been obtained and
notifications sent before any work begins in the jurisdictional
areas.
5.1 Erosion Control Measures
5.2 Flow Diversion
5.3 Impervious Dikes
5.4 Dewatering
5.5 Temporary Stream Crossings
5.6 Ground Stabilization
5.7 Outlet Stabilization
5.8 Maintaining Normal Flow
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 51
5.1 EROSION CONTROL
Erosion control consists of ineasures taken to prevent sediment
from leaving the job site. These controls intercept and settle
sediment from runoff before it is discharged from the project.
Erosion controls also help reduce velocity and reduce the erosive
force of runoff. All erosion and sedimentation devices should be
placed outside of wetlands, streams, and buffer areas.
5.1.1
5.1.2
5.1.3
Temporary Silt Fence
Special Sediment Control Fence
Temporary Silt Ditch
5.1.4 Temporary Rock Silt Check Type "A"
5.1.5
North Carolina Department of Transportation
August2003
Temporary Rock Sediment Dam Type "B"
BMPs for Construction and Maintenance Activities
Page 52
5.1 - Erosion Control
5.1.1 Temporary Silt Fence
Purpose A temporary sediment device consisting of geotextile fabric
installed between supporting posts. The silt fence intercepts
water flow from the site, decreases velocity, and causes
suspended particles to settle.
Conditions Where
Practice Applies:
Conditions Where
Practice Does Not
Apply:
Construction
Figure 25. Silt Fence
✓ Below small disturbed areas less than '/4 acre per 100 feet of
fence.
✓ Where runoff can accumulate behind the sediment fence
without damaging the fence or the inundated area behind the
fence.
✓ Do not install sediment fences across streams, ditches,
waterways or areas that have concentrated flow.
• Reference Std. 1605.01 — Erosion and Sedimentation Control
Field Guide.
• Reference Section 1605 — Standard Specifications for Roads
and Structures, Current Edition
• Reference Std. 1605.01 — Roadway Standard Drawings,
Current Edition
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 53
5.1- Erosion Control
Maintenance . Inspect silt fences on a regular basis and after each rainfall.
Make any required repairs immediately.
• Inspect silt fence to be sure bottom edge is keyed in properly.
• Remove and replace deteriorated or clogged silt fence.
• Remove and dispose of sediment accumulations when depth
reaches one-half the height of the filter fabric. Take care to
avoid undermining the fence during cleanout.
• Replace silt fence removed for access at the end of each
day's operation.
• Install additional posts or wire backing if fence is sagging.
Typical Problems • Improper installation (bottom of fabric not buried or keyed-in
properly.
• Failure due to installation across streams, ditches, waterways,
and other areas that receive concentrated flow.
• Excessive sediment accumulations.
• Knocked down or cut by fallen trees, equipment, excess water
flows, or for work access.
• Inadequate access to maintain and remove fence.
• Installed across contours creating channelized flow behind
fence.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 54
5.1.2
5.1- Erosion Control
Special Sediment Control Fence
Purpose A special sediment control fence is a hardware cloth with
sediment control stone at the base and contained by wire mesh
fence. Water from the site drains through the sediment control
stone causing sediment to be trapped or settle.
Figure 26 — Typical Special SecJiment Control Fence
Conditions Where Where the volume of water is too extensive for a silt fence
Practice Applies: Where inadequate right of way is available for a silt ditch
Conditions Where Where topography forces water to run along the base of the
Practice Does Not sediment control stone instead of allowing the water to pond up
Apply and flow through the stone.
Construction • Reference Std. 1606.01 — Erosion and Sediment Control Field
Guide.
Maintenance • Inspect sediment control fence on a regular basis and after
each rainfall. Make any required repairs immediately.
• Remove and replace clogged sediment stone.
• Install additional posts or wire if fence is sagging.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 55
Purpose
Conditions Where
Practice Applies
5.1 - Erosion Control
5.1.3 Temporary Silt Ditch
Used in place of Silt Fence where room allows. Use in
conjunction with Rock Sediment Dams or other measures to
contain sediment at the outlet.
Figure 27. Temporary Silt Ditch
✓ Toe of fill slopes where fill exceeds 3 feet (1 meter) in vertical
height.
✓ Adjacent streams to intercept flow and/or divert to a controlled
outlet.
✓ Along project perimeters to minimize sediment loss from the
site.
Conditions Where ✓ Within jurisdictional waters and wetlands.
Practice Does Not ✓ When access is difficult due to high fill slope.
App�Y
Construction • Reference Std. 1630.03 — Erosion and Sediment Control Field
Guide.
• Reference Std. 1630.03 — Roadway Standard Drawings,
current edition.
Maintenance
• Clean out sediment when silt ditch is one half full.
• Rebuild ditch daily when damaged by equipment or covered
by fill.
• Inspect erosion control devices at outlet. Remove sediment
and repair any damage.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page56
5.1- Erosion Control
Typical Problems . Excessive sediment accumulations.
• Outlet protection not maintained.
• Requires room for stockpiling sediment cleanout material or
material must be hauled off from the site.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 57
Purpose
Conditions Where
Practice Applies:
Conditions Where
Practice Does Not
Apply:
Construction
5.1.4
5.1 - Erosion Control
Temporary Rock Silt Check Type "A"
A small dam with a weir outlet that uses a naturally-formed
storage area to trap sediment (rather than an excavated pit).
These are generally referred to as check dams.
Figure 28. Rock Silt Check Type "A"
✓ In channels, roadside ditch outlets, temporary silt ditches, and
temporary diversions.
✓ In conjunction with Type-B silt basins.
✓ In channels where sandy soil prohibits the use of Type-B silt
basins.
✓ In jurisdictional wetlands without any excavation, Type B silt
basins, and any silt deposits must be removed upon
completion.
✓ These check dams may not be placed in live streams
• Reference Std. 1633.01 — Erosion and Sediment Control Field
Guide.
• Reference Section 1633 — Standard Specifications for Roads
and Structures, Current Edition
• Reference Std. 1633.01 — Roadway Standard Drawings,
Current Edition
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page58
5.1- Erosion Control
Maintenance . Inspect after each significant rainfall.
• Remove sediment from device when sediment accumulates.
• Rebuild and reshape structure and weir when damaged.
• Clean out when clogged by straw, limbs, or other debris.
Typical Problems • Rock structure is not rebuilt when damaged by storms,
equipment, etc.
• Rock weir sections are not constructed properly.
• When weir is constructed higher than outside edges, water
may flow around dam and erode ditch.
• Not built wide enough to intercept ditch slope at top of check
dam.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 59
5.1 - Erosion Control
5.1.5 Temporary Rock Sediment Dam Type "B"
Purpose A small Class B stone dam with sediment control stone and built
in sediment basin. Typically, used at the outlets of roadside
ditches or channels to impound and settle runoff prior to entering
streams or exiting site.
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Conditions Where ✓ At outlets of temporary diversions, temporary silt ditches,
Practice Applies: channels, and temporary slope drains.
✓ In locations where dam can be cleaned and maintained on a
regular basis.
✓ In locations where runoff is exiting the construction site.
✓ In small natural drainage turnouts.
Conditions Where
Practice Does Not
Apply:
Construction
✓ Use may be limited in buffer zones
• Reference Std. 1634.02 — Erosion and Sediment Control Field
Guide.
• Reference Std. 1634.02 — Roadway Standard Drawings,
Current Edition
• Reference Section 1634 — Standard Specifications for Roads
and Structures, Current Edition.
Maintenance • Inspect after each significant rainfall.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 60
Typical Problems
5.1- Erosion Control
• Remove sediment from device when sediment accumulates to
one-half the basin area formed by the dam.
• Remove and replace sediment control stone when water no
longer drains between rainfall events.
• Rebuild and reshape structure and weir when damaged.
• Clean out when clogged by straw, limbs, or other debris.
• Sediment accumulations are not removed when needed.
• Structure not rebuilt when damaged.
• Rock weirs are not constructed properly.
• Stone is not cleaned or replaced when clogged.
• Stone is not tied into slopes.
• Fabric not placed under stone for reinforcement
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 61
5.2 FLOW DIVERSION
The normal flow of a stream must be diverted and the work area
isolated to allow a project to proceed. The watercourse should be
managed to minimize adverse impacts to the jurisdictional
waters. All projects should be planned to minimize the time that
the watercourse will be diverted.
Several methods of diverting a watercourse are provided in this
section. There may be certain seasonal components to consider
when attempting flow diversion of a stream, such as spawning
times of individual fish species.
5.2.1
5.2.2
5.2.3
Bypass Pumping
Suspended Bypass Pipe
Piped Diversion
5.2.4 Fabric Lined Diversion Channel
North Carolina Department of Transportation
August2003
BMPs for Construction and Maintenance Activities
Page 62
5.2 - F/ow Diversion
5.2.1 Bypass Pumping
Purpose A bypass pump and an impervious dike divert the flow of the
watercourse from the inlet of the pipe to the outlet of the pipe.
This is a water-to-water operation and care should be taken that
the discharge is at a low flow rate to minimize turbidity at the
outlet of the bypass pipe and/or eroding the channel.
Figure 30. Bypass Pumping
Conditions Where ✓ When another type of diversion is not physically possible or
Practice Applies practical.
✓ When the repair or construction activities will not require
pumping for an extended period of time.
Conditions Where ✓ When the discharge location can not be adequately stabilized
Practice Does Not ✓ When ponding of the stream to adequately submerge the
Apply pump suction line is not allowed or not practical.
✓ When the normal flow of the stream cannot be handled by the
typical bypass pump.
Construction Step 1— Set up bypass pump and temporary piping. Place outlet
of temporary pipe to minimize erosion at discharge site or provide
temporary energy dissipation measures. Firmly anchor pump
and piping.
Step 2— Construct outlet protection if needed.
Step 3— Construct impervious dike upstream of work area to
impound water for bypass pump intake. Use a floating intake for
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 63
5.2 — F/ow Diversion
pumps where possible.
Step 4— Construct an impervious dike downstream, if necessary,
to isolate work area.
Step 5— Check operation of pump and piping system Step 4-
Step 6— Upon completion of construction, remove impervious
dike, bypass pump, and temporary pipe.
Maintenance • Routinely inspect bypass pump and temporary piping to
ensure proper operation.
• Inspect impervious dike for leaks and repair any damage.
• Inspect discharge point for erosion.
Typical Problems
• Ensure flow is adequately diverted through pipe.
• Pump failure.
• Erosion at outlet.
• Leaks in piping and improper connection to pump.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 64
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5.2.2 Suspended Bypass Pipe
Purpose The suspended bypass pipe is used where an existing pipe or
culvert is extended. This bypass pipe is constructed inside the
existing pipe or culvert to divert the watercourse through the work
area while allowing the work area to remain dry.
Conditions Where
Practice Applies
Conditions Where
Practice Does Not
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✓ When a pipe or culvert is being extended and is large enough
to accommodate the bypass pipe.
✓ When space limitations do not allow for a fabric lined
diversion channel
✓ When the upstream ponding required to enter the suspended
pipe inlet is unacceptable.
Construction Step 1— Install sediment controls.
Step 2— Install temporary pipe through the existing pipe or
culvert to be extended. Place outlet of temporary pipe to
minimize erosion at discharge site or provide temporary energy
dissipation measures.
Step 3— Construct an impervious dike upstream of the work area
to divert flow through the temporary pipe. Anchor and seal
temporary pipe securely at inlet.
Step 4— Construct an impervious dike at the downstream side of
the bypass pipe to isolate work area.
Step 5— Upon completion of the culvert or pipe extension,
remove the impervious dike and temporary pipe.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 66
5.2 — F/ow Diversion
Maintenance . Inspect the inlet regularly and dike for damage and/or leakage
and to ensure flow is adequately diverted.
• Remove sediment and trash that accumulate behind the dike
and at the inlet on a regular basis.
• Inspect the outlet regularly for erosion and to ensure flow is
adequately diverted through the system.
Typical Problems
• Failure because inlet is not properly anchored and sealed.
• Erosion at outlet.
• Inlet clogged with debris.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 67
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5.2.3 Piped Diversion
Purpose Install a temporary pipe to divert the flow of the watercourse
around the work area without the use of pumping operations.
While the cost is higher for this operation, the probability of offsite
sediment loss is much lower than with an open diversion channel.
Conditions Where
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Conditions Where
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Construction
Maintenance
✓ Where adequate slope and space exist between the upstream
and downstream ends of the diversion.
✓ Pipe extensions, headwall installations and some pipe/culvert
replacements where adequate space is unavailable.
✓ When the pipe would adversely impact the aquatic habitat
migration.
Step 1— Install sediment controls.
Step 2— Install temporary pipe adjacent to work area.
Excavation may be required to provide a positive drainage slope
from the upstream to downstream side.
Step 3— Connect the downstream temporary pipe into the
downstream existing channel. Place outlet of pipe to minimize
erosion at the discharge site or provide temporary energy
dissipation measures.
Step 4— Connect the upstream temporary pipe into the upstream
existing channel.
Step 5— Construct an impervious dike at the upstream side of
the existing channel to divert the existing channel into the
temporary pipe.
Step 6— Construct an impervious dike at the downstream side of
the bypass pipe to isolate work area.
Step 7— Upon completion of construction, remove the
impervious.
• Inspect diversion berm and piping for damage.
• Remove accumulated sediment and debris from berm and
inlet.
• Inspect outlet for erosion.
Typical Problems • Improper amount of slope that impedes diverted flow.
• Diverted flow bypasses the temporary pipe and causes
erosion as surface flow.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 69
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5.2 - F/ow Diversion
5.2.4 Fabric Lined Diversion Channel
Purpose Used to divert the normal flow and small storm events around the
work area without the use of pumping operations. The diversion
channel is typically constructed adjacent to the work area and is
lined with a poly-fabric to prevent erosion of the diversion
channel.
Conditions Where
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Conditions Where
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Construction
Figure 32. Fabric Lined Diversion Channel
✓ When adequate space and slopes exist adjacent to the work
area.
✓ Pipe extensions, headwall installations and some pipe/culvert
replacements where adequate space is unavailable.
Step 1— Install sediment controls.
Step 2— Excavate the diversion channel without disturbing the
existing channel.
Step 3—Place poly-fabric liner in diversion channel with a
minimum of 4 feet of material overlapping the channel banks.
Secure the overlapped material using at least 1 foot of fill
material.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page71
Maintenance
5.2 — F/ow Diversion
Step 4— Connect the downstream diversion channel into the
downstream existing channel and secure the poly-fabric liner at
the connection.
Step 5— Connect the upstream diversion channel into the
upstream existing channel and secure the poly fabric liner at the
connection.
Step 6— Construct an impervious dike in the existing channel at
the upstream side to divert the flow into the diversion channel.
Step 7— Construct an impervious dike in the existing channel at
the downstream side to isolate the work area.
Step 8— Upon completion of the culvert construction, remove the
impervious dikes and divert the channel back into the culvert.
Step 9— Remove the poly-fabric liner and fill in the diversion
channel.
Step 10 — Establish vegetation on fill section and all other bare
areas.
• Check the poly-fabric liner for stability during normal flow
• Check the liner for stability after each rainfall event
Typical Problems • Improperly installed liners.
• Filter fabric not installed (secured) properly.
• Earthen material allowed to come into contact with water
body.
• There maybe certain times of the year, especially in the
summer, when fabric-lined channels may cause thermal
pollution. This could be a problem in trout waters during
certain times of the year.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 72
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5.2.5 Turbidity Curtain
Purpose Used as instream erosion control filtration device to isolate the
streambank work from the normal flow of the stream. This device
is normally used in open waters for containment in work zones.
May also be used across channels with very low flow for short-
term work when anchored properly.
Conditions Where
Practice Applies
Conditions Where
Practice Does Not
Apply
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✓ When performing work on a stream bank in a small localized
area.
✓ When the repair or construction activities will not require an
extended period of time to complete.
✓ Across flowing streams. Turbidity curtains are not designed
as prefabricated dams.
Construction The curtain should be made of a tightly woven nylon, plastic or
other non-deteriorating material. The material shall meet the
following specifications:
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 74
Maintenance
5.2 — F/ow Diversion
Propertv Value
Grab tensile strength '`md-370 Ibs. (1.65 Kn) *cd-250 Ibs
Mullen burst strength 480 psi (3307 kpa)
Trapezoid tear strength *md-100 Ibs. (0.45 Kn) *cd-60 Ibs.
Apparent opening size 70 us standard sieve (0.210 mm)
Percent open area 4% permittivity 0.28 sec-1
*md — machine direction
*cd — cross machine direction
(1.11 Kn)
(0.27 Kn)
• A flotation material with over 29 Ibs./ft. (43 kg/m) buoyancy
shall support the curtain material. A 5/16 inch (7.8 mm)
galvanized chain shall act as ballast for the floating curtain.
Dual 5/16 inch (7.8 mm) galvanized wire ropes with a heavy
vinyl coating shall be used as the load lines.
• Inspect the curtain, flotation and ballast to ensure the work
area is securely partitioned from the stream flow.
• Remove accumulated sediment and debris.
Typical Problems • Does not permanently remove sediment.
• Improper anchoring of curtain on channel bottom.
• Tidal flows requiring frequent repositioning
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 75
5.3 IMPERVIOUS DIKES
Impervious dikes are used to divert normal stream flow around a
construction site. Acceptable materials for impervious dikes
include, but are not limited to, sheet piles and sandbags and/or
the placement of an acceptable size stone lined with
polypropylene or other impervious fabric. Also, prefabricated
dams and/or the placement of appropriately sized stone lined with
polypropylene or other impervious fabric can be used. Earthen
material should not be used to construct an impervious dike when
it is in direct contact with the stream unless cover of vegetation
can be established before there is contact with the stream.
5.3.1 Stone with Impervious Fabric
5.3.2 Sand Bags
5.3.3 Prefabricated Dams
5.3.4 Sheet Piles
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 76
5.3 - Impervious Dikes
5.3.1 Stone with Impervious Fabric
Purpose A stone dike encapsulated with a high tensile impervious
geotextile fabric material to create a temporary impervious barrier
that will either impound or divert water. This barrier can be
constructed to the shape of the existing channel.
Conditions Where
Practice Applies
Conditions Where
Practice Does Not
Apply
Construction
Figure 34. Installation of Stone with Impervious Fabric
✓ When the size of the pipe is less than 48-inches.
✓ When heavy equipment can be used for installation.
✓ When the pipe is 48-inches or greater
Step 1— Prepare the channel and overbanks for installation.
• Remove all branches and debris from location of the stone
dike.
• Make sure that there are no sharp rocks or roots that can
puncture the fabric.
• Do not excavate the existing channel or banks.
Step 2— Place the high tensile impervious fabric with the center
over the center of the proposed dike. Utilize a small amount of
stone to hold down the fabric while adjustments are being made.
Ensure there is enough extra fabric on each side of the dike to
wrap up and over the stone dike to make it impervious.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page77
Maintenance
Typical Problems
5.3 — Impervious Dike
Step 3— Pile stone on top of the fabric to create dike.
Step 4— Roll fabric up over the stone to form an impervious dike.
Make sure the top layer is rolled from the upstream to
downstream direction. Secure fabric with metal fence stakes or
other suitable material.
• Inspect dike regularly for damage and leakage.
• Remove impounded trash and sediment.
• Leaks through puncture in fabric.
• Blow-out by large storm events.
• Erosion around the side of dike.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 78
5.3 - Impervious Dikes
5.3.2 Sand Bags
Purpose Filter bags filled with sand can be manually stacked to form a
temporary impervious dike when encapsulated with an
impervious poly-fabric liner. This impervious dike can be used to
impound or divert water and can be easily removed.
Figure 35. Sand Bag Installation
Conditions Where ✓ Used when low flow rates exist.
Practice Applies ✓ Used when the height of the dike is less than 15 feet.
✓ Used when heavy equipment cannot be utilized.
Conditions Where
Practice Does Not
App�Y
Construction
✓ Concrete is not allowed in sand mixture.
Step 1— Remove branches and large rocks from area where the
sand bags will be placed.
Step 2— Lay out the impervious poly-fabric liner with the center
of the liner located over the center of the sand bag dike.
Step 3— Place the sandbags to the desired height. The dikes
shall have a width suitable to support the height. Each row shall
be offset so the joints are staggered. Pack sandbags tightly
together.
Step 4— Wrap impervious poly-fabric liner around sandbag dike
and secure with final layer of sandbags.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page79
Maintenance
Typical Problems
5.3 — Impervious Dike
• Periodically inspect sandbag dike for damage and leaks.
• Remove impounded trash and sediment.
• Leakage due to improper construction or liner failure.
• Blow-out by large storm event.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 80
5.3 - Impervious Dikes
5.3.3 Prefabricated Dams
Purpose Prefabricated dams are typically made of an impervious poly-
fabric that can be placed in an existing channel. The weight of
the water is used to hold the prefabricated dam in place to
temporarily impound or divert water.
Conditions Where
Practice Applies
Conditions Where
Practice Does Not
Apply
Figure 36. Prefabricated Dam
✓ When there is a normal flow in the existing channel.
✓ When the area of the temporary dam will not puncture the
dam.
✓ Where there is no water to hold the temporary dam in place.
Construction There are various types and manufacturers of prefabricated
temporary dams. The construction guidelines given below are
typical. Prefabricated dams shall be installed based on the
manufacturers installation guidelines.
Step 1— Remove the branches, debris, sharp rocks and roots
where the prefabricated dam is to be placed.
Step 2— Place the prefabricated dam in the channel bottom and
utilize sandbags or heavy rocks to temporarily anchor to the
bottom of the channel.
Step 3—Secure each end upslope above the toe.
Step 4— Allow the prefabricated dam to utilize the upstream
water pressure to seal the dam and impound or divert the water.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page81
Maintenance
Typical Problems
5.3 — Impervious Dike
• Monitor prefabricated dam for volume of water flowing,
inherent safety, and dam stability.
• Poor sealing between the prefabricated dam and the bottom
of the channel.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 82
5.3 - Impervious Dikes
5.3.4 Sheet Piles
Purpose A flat cross-section piling that is driven into the ground and
interlocked to create a wall or bulkhead. Sheet piles can be used
to detain water in low-flow situations or coupled with bypass
pumps to keep a site moderately dry during construction.
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'n�'i�:� � � �� �,�' ��i y-�j�'
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Figure 37. Sheet Piles
Conditions Where ✓ Where minimum channel disturbance is required.
Practice Applies ✓ Preferred method of sealing the work area from the
watercourse on pipe sizes of 48" and greater.
Conditions Where ✓ Small channel with little or no flow.
Practice Does Not ✓ Where the access to drive piles requires more disturbance to
Apply jurisdictional areas than other impervious dikes.
✓ Locations where rocks and other obstructions prevent piles
from being driven
Construction . Install by placing and driving piles with a backhoe, excavator,
hammer, or other suitable equipment.
• Be sure pile is free of dirt, grease and other potential
contaminants before installation.
• Ensure the piles penetrate to a sufficient depth in order to
bear the load of water being diverted.
� Overlap or interlock piles in a manner that prevents any
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 83
Maintenance
Typical Problems
5.3 — Impervious Dike
seepage of water into the work area and prevents seepage of
sediment from the work area into the stream.
• Remove trapped debris and sediment prior to removing.
• Inspect sheet piles daily for water leaks and signs of instability
and implement repair procedures accordingly.
• Improperly installed piles cause leaks.
• Piles not driven deep enough to withstand pressure of water.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 84
5.4 DEWATERING
Dewatering is the practice of removing water from the work area.
This water is considered effluent polluted and must be treated to
remove sediment before being discharged into a stream, channel,
or other area. Effluent water is typically pumped out of the work
area and into one of the erosion control devices identified in this
section before being discharged from the site.
5.4.1
5.4.2
North Carolina Department of Transportation
August2003
Stilling Basin for Pumped Effluent
Special Stilling Basin (Silt Bag)
BMPs for Construction and Maintenance Activities
Page 85
Purpose
Conditions Where
Practice Applies
5.4 - Dewatering
5.4.1 Stilling Basin for Pumped Effluent
Used at sites where dewatering of the work area is required to
perForm work. The effluent is pumped into the stilling basin to
allow the heavier particles to settle out prior to being discharged.
Figure 38. Stilling Basin for Pumped Effluent
✓ Where there is enough room in the work area to form or
excavate the basin.
✓ Where large volumes of water will be pumped from the work
area.
Conditions Where ✓ Not allowed to be constructed in jurisdictional wetlands
Practice Does Not ✓ Should not be built in ditch lines.
App�Y
Construction • Reference Std. 1630.04 — Erosion and Sediment Control Field
Guide.
• Reference Std. 1630.04 — Erosion and Sedimentation Control
Guidelines for Contract Construction.
Maintenance
Typical Problems
• Inspect basin after each significant rainfall.
• Basin should be cleaned out when approximately one half full.
• Clean and replace sediment control stone when needed.
Inadequate basin capacities — basins are not constructed to
dimensions specified on plans.
Accumulated sediment not removed when needed.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page86
5.4 - Dewatering
• Basins built in sandy soils may cause sloughing of slopes.
• Erosion occurs at inlet end when basin is too deep.
• Pump discharge entering too close to outlet.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 87
5.4 - Dewatering
5.4.2 Special Stilling Basin (Silt Bag)
Purpose Used at sites where the construction limits do not allow for the
construction of a stilling basin. The effluent from the work area is
pumped into a prefabricated silt bag. Water slowly filters out of
the bag in a dispersed manner and the sediment is captured in
the bag. Sediment control stone is used as a foundation for the
bag.
Figure 39. Silt Bag
Conditions Where ✓ When the effluent can be pumped out of the work area at a
Practice Applies rate of 1500 gallons per minute or less.
✓ When the work area and dewatering volume is small.
✓ When there is not enough available non-jurisdictional area to
excavate stilling basin.
✓ When the repair or construction activities will not require an
extended period of time.
Conditions Where
Practice Does Not
Apply
✓ Construction sites that will require large amounts of
dewatering.
Construction . The silt bag shall be at least 10 ft. by 15 ft. The bag should
be made from a nonwoven fabric and have a sewn-in sleeve
for receiving pump discharge.
• The sediment control stone shall meet the requirements of
Section 1005.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page88
Maintenance
Typical Problems
5.4 - Dewatering
• The bag seams should be sewn with a double needle
machine using a high strength thread. The seams shall have
a wide width strength of at least 60 Ib./in. (using test method
ASTM D-4884).
• The filter fabric shall meet the requirements of Section 1056
for Type 2 fabric. It shall also meet the following
specifications for flow rates, strength, and permeability:
Property Test Method
Weight ASTM D-3776
Grab tensile ASTM D-4632
Puncture ASTM D-4833
Flow rate ASTM D-4491
Permittivity ASTM D-4991
UV Resistance
Units Minimum
Specifications
oz/yd 8.0
Ib. 200.0
Ib. 130.0
gal/min/s.f. 80.0
1 /sec 1.5
ASTM D-4355 %70.0
The silt bag shall be placed on top of at least 6-inches of
sediment control stone in an area that will drain away from the
work area. Plan ahead for acceptable methods of removal
and disposal of silt bag.
• Inspect inlet pipe and bag for damage and blockage.
• Replace bag when 3/4 full of sediment.
• Discharge too large for pump.
• Pump is too large.
• Continued use when bag is full.
• Inlet pipe disconnected from bag.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 89
5.5 TEMPORARY STREAM CROSSINGS
Temporary stream crossings provide a means for construction
equipment to cross streams. The goal is to keep sediment
generated by construction traffic out of the water body and
minimize the impacts to the stream channel's bottom and banks.
Without a stabilized crossing, the constant disturbance of the
channel's bottom and banks by construction traffic will result in
downstream impacts.
5.5.1
5.5.2
5.5.3
North Carolina Department of Transportation
August2003
Temporary Fording
Temporary Piped Crossing
Temporary Access Bridge
BMPs for Construction and Maintenance Activities
Page 90
5.5 - Temporary Stream Crossings
5.5.1 Temporary Fording
Purpose The temporary ford uses filter fabric and stone to provide a stable
crossing that can be easily removed. These crossings are best
suited for streams with a rock channel bottom and having no
normal flow. A temporary rock filter should be constructed
downstream to capture sediment deposited on the crossing by
equipment that may be washed away during storm events.
Figure 40. Temporary Fording (Device should be constructed
during no flow conditions)
Conditions Where ✓ When performing work and the only equipment access is to
Practice Applies cross a stream.
✓ Fording should only be used on small streams having
intermittent flow. Timing of these impacts should be during no
flow periods.
✓ Where adequate space is available to accommodate the
temporary ford and any construction across the channel.
✓ Where banks can be graded back to a slope that will allow
equipment access if needed.
Conditions Where
Practice Does Not
ApP�Y
✓ Streams with normal flows.
✓ Sites where instream moratorium periods apply.
Construction Temporary fords should be constructed with Class-A or riprap
structural stone over a Type II filter fabric. The crossing must be
installed so that erosion during construction and use is minimized.
Step 1— Locate crossing where approaches and crossing will
disturb the least amount of the channel's bank and bottom.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page91
5.5 - Temporary Stream Crossings
Step 2— Divert stormwater runoff from the top of the approaches
to prevent runoff flowing down the approach and into the stream.
Step 3— If needed, construct approaches by pulling soil back
away from the stream channel. Do not contour the bank by
pushing the soil down into the stream.
Step 4— Center filter fabric on crossing and temporarily anchor
ends.
Step 5— Place stone over fabric on approaches and across
stream channel.
Step 6— Construct temporary rock filter downstream of crossing.
Step 7- Completely remove all of the ford from stream when
construction is complete.
Step 8— If over-widening of stream channel occurs, structures
(i.e. floodplain bench, rock vanes, etc.) will need to be installed to
restore natural stream pattern and dimension profile.
Maintenance • Inspect the ford to ensure that stormwater runoff is diverted
away from approach ramps.
• Inspect crossing for erosion and/or damage by construction
traffic.
Typical Problems
• Inspect temporary rock filter. Remove accumulated sediment
and repair any damage.
• Revegetate the stream-side buffers when the crossing
approach is complete.
• Channelization and erosion of approaches from off-site
stormwater runoff.
• Over-widening the stream at the crossing location.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 92
5.5 - Temporary Stream Crossings
5.5.2 Temporary Piped Crossing
Purpose Provides a means for equipment to cross streams while
minimizing the impact of sediment to the stream channel. The
temporary crossing uses filter fabric, stone, and piping to provide
a stable travel surface that does not restrict normal flow and flow
during minor storm events. Ensure stone size is large enough
when required to help prevent washouts.
Conditions Where
Practice Applies
Conditions Where
Practice Does Not
Apply
Construction
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t Figure 41. Temporary Piped Crossing
✓ When the existing channel has a normal flow.
✓ When performing work and the only equipment access is to
cross a stream.
✓ Sites where instream work moratoriums apply, such as
anadromous fish species, etc.
Step 1— Locate crossing where approaches and crossing will
disturb the least amount of the channel's bank and bottom.
Step 2— Divert stormwater runoff from the crossing approaches
to prevent runoff flowing down the approach and into the stream.
Step 3— If needed, construct approach ramps by pulling soil back
away from the stream channel. Do not contour the bank by
pushing soil into the stream. Disturbing stream banks to construct
approach ramps should only be undertaken where stone for the
crossing cannot effectively be raised to the level of the top of
bank.
Step 4— Center filter fabric on the crossing and temporarily
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 93
5.5 - Temporary Stream Crossings
anchor ends.
Step 5— Place washed stone over filter fabric across stream
channel.
Step 6— Install temporary pipes on bed of washed stone and
cover with stone to a depth sufficient to support equipment loads.
Soil should not be used as backfill material.
Step 7— Armor sides and top of fill to prevent erosion and provide
a firm travel surface.
Step 8— If approach ramps have been excavated, armor side
slopes with riprap to prevent erosion when water flows over
crossing.
Step 9— Completely remove crossing immediately upon
completion of construction. Establish permanent vegetation on
graded areas outside of stream channel.
Maintenance • Inspect crossing daily and after each rainfall event for
damage.
• Inspect runoff diversions along approaches.
• Keep pipes clear of debris.
Typical Problems
• Need to revegetate the stream-side buffers when the crossing
approach is complete.
• Runoff channelizes and erodes approaches to the stream
crossing.
• Damage to crossing from high flow events.
• Erosion of side slopes where approach ramps are used.
• Flooding upstream due to crossing not being properly
designed to handle large flows because over-topping of
crossing not allowed or pipes are too small.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 94
Purpose
5.5 - Temporary Stream Crossings
5.5.3 Temporary Access Bridge
The temporary access bridge is a stream crossing made of wood,
metal, or other materials designed to limit the amount of
disturbance to the stream banks and bed.
Figure 42. Temporary Access Bridge
Conditions Where ✓ Streams with normal flows.
Practice Applies ✓ Sites where seasonal instream work moratoriums apply.
✓ When performing work and the only equipment access is to
cross a stream.
✓ Where adequate space is available to accommodate the
temporary bridge and any construction across the channel.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 95
Conditions Where
Practice Does Not
Apply
5.5 - Temporary Stream Crossings
✓ Channels with little or no base flows
✓ Short construction time frame.
Construction All erosion and sedimentation control devices, including stream
diversions, should be implemented first. Finally, dewatering
basins should be built as needed and swales or ditches should be
used to prevent surface drainage from entering the stream via the
bridge crossing. The proposed construction, maintenance, and
removal sequence is as follows:
Step 1- Abutments should be placed parallel to, and on, stable
banks such that the structure is at or above bankfull depth to
prevent the entrapment of floating materials and debris.
Step 2- Temporary access bridges should be constructed to
span the entire channel. If the bankfull channel width exceeds 8
feet (2.5 meters), then a footing, pier, or other bridge support may
be constructed within the waterway. No support will be permitted
within the channel for waterways less than 8 feet wide. One
additional bridge support will be permitted for each additional 8-
foot width of the channel.
Step 3- All decking members should be placed perpendicularly to
the stringers, butted tightly, and securely fastened to the stringers.
Decking materials must be butted tightly to prevent any soil
material tracked onto the bridge from entering the waterway.
Step 4-Although run planks are optional, they may be necessary
to properly distribute loads. One run plank should be provided for
each track of the equipment wheels and should be securely
fastened to the length of the span.
Step 5- Curbs or fenders may be installed along the outer sides
of the deck to provide additional safety.
Step 6- Bridges should be securely anchored at one end using
steel cable or chain to prevent the bridge from floating
downstream and possibly causing an obstruction to the flow.
Anchoring at only one end will prevent channel obstruction in the
event that flood waters float the bridge. Acceptable anchors are
large trees, boulders, or driven steel anchors.
Step 7- All areas disturbed during installation should be
stabilized.
Step 8- When the temporary bridge is no longer needed, all
structures including abutments and other bridging materials
should be removed. In all cases, the bridge materials should be
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 96
5.5 - Temporary Stream Crossings
removed. Removal of the bridge and clean-up of the area,
including protection and stabilization of disturbed stream banks,
should be accomplished without the use of construction
equipment in the waterway. Any debris that falls into the stream
during removal should be taken out.
Maintenance • Periodic inspection should be performed by the user to ensure
that the bridge, streambed, and stream banks are maintained
and not damaged
• Maintenance should be performed as needed to ensure that
the structure complies with all standards and specifications.
This should include the removal of trapped sediment and
debris which should then be disposed of and stabilized
outside the floodplain.
Typical Problems • Construction debris falling into stream.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 97
5.6 GROUND STABILIZATION
After completion of construction or land disturbing activities, all
disturbed areas must be stabilized to prevent future erosion. The
establishment of a good vegetative cover helps protect soil from
the impact of raindrops and reduces the erosive forces of runoff.
Hard armor protection, such as riprap, helps protect areas that
cannot be stabilized with vegetative cover.
5.6.1 Temporary Seeding and Mulching
5.6.2 Permanent Seeding and Mulching
5.6.3 Erosion Control Blankets
5.6.4
5.6.5
North Carolina Department of Transportation
August2003
Riprap Slope Protection
Riprap Outlet Protection
BMPs for Construction and Maintenance Activities
Page 98
Purpose
5.6 - Ground Stabilization
5.6.1 Temporary Seeding and Mulching
To prevent erosion of exposed soil material by covering with
mulch and quick germinating seed mixture. Disturbed areas may
need planting of woody species, in addition to seeding.
Figure 43 — Temporary Seeding
Conditions Where ✓ When work areas will not be active for more than 15 days
Practice Applies ✓ Prior to anticipated precipitation events which will severely
damage work performed orjurisdictional areas.
Conditions Where
Practice Does Not
Apply
Construction
✓ Permanent stabilization
✓ Areas permanently under water.
Reference Section 1620 — Standard Specifications for Roads and
Structures, Current Edition
Maintenance • Inspect after heavy rains and repair seed and mulch bare
areas until vegetative cover is established.
• Inspect seeded areas periodically until vegetation has
permanently stabilized. Repair damaged areas or failure
accordingly.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page99
5.6 — Ground Stabilization
Typical Problems . Inadequate seed germination due to use of wrong seed mix
for season or regional area, poor seed bed preparation, or
poor fertilizer application.
• Insufficient amount of tack on mulch.
Inadequate seed bed preparation.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 100
5.6 — Ground Stabilization
5.6.2 Permanent Seeding and Mulching
Purpose Perform as soon as possible after final grade is complete to
stabilize the site and minimize erosion. Coordination with seeding
crews prior to completion of the project is essential. Disturbed
areas may need planting of woody species in addition to seeding.
Figure 44. Permanent Seeding and Mulching
Conditions Where ✓ On all bare soil that will not be perennially under water or
Practice Applies covered with a permanent land cover such as riprap, stone,
asphalt, or concrete.
Conditions Where
Practice Does Not
App�Y
Construction
✓ Areas that are perennially under water.
• Reference Section 1660 — Standard Specifications for Roads
and Structures. Current edition.
• Shall be performed within 15 working days unless otherwise
specified in the permit conditions or in the contract
specifications. Work day means days exclusive of Saturday
and Sunday during which weather conditions or soil conditions
permit land-disturbing activities to be undertaken.
• Topdressing shall be conducted in a manner that is consistent
• Do not overspray tacking material into stream during operation
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 101
Maintenance
Typical Problems
5.6 — Ground Stabilization
• Inspect after heavy rains and repair seed and mulch bare
areas until vegetative cover is established.
• Inspect seeded areas periodically until vegetation has
permanently stabilized. Repair damaged of failure areas
accordingly.
• Inadequate seed germination due to use of wrong seed mix
for season or regional area, poor seed bed preparation or
poor fertilizer application.
• Insufficient amount of tack on mulch.
• Inadequate seed bed preparation.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 102
5.6 - Ground Stabilization
5.6.3 Erosion Control Blankets
Purpose A temporary blanket of thin biogradable materials is bound
together between a plastic material. The blankets are placed over
a surface that has been properly prepared and seeded. The
blanket is stapled or stacked in place. An erosion control blanket
serves as mulch and ultimately becomes part of the vegetation
layer that protects the soil.
Figure 45. Erosion Control Blankets
Conditions Where ✓ In drainage ditches to prevent erosion and scour prior to the
Practice Applies establishment of vegetation.
✓ On steep slopes where normal mulching practices will readily
erode during a rainfall event. Always check manufacturer
slope velocity limits for specific blankets.
✓ On slopes less than 2:1 to provide slope protection/
stabilization around inlets and outlets of pipes.
Conditions Where ✓ In areas that are perennially inundated with water.
Practice Does Not ✓ In area where slope and water velocity exceeds blanket
Apply capabilities.
Construction Reference Section 1631 — Standard Specifications for Roads and
Structures, Current edition.
Maintenance . Reshape, repair, or replace damaged erosion control
blankets.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 103
Typical Problems
5.6 — Ground Stabilization
• Secure staples that become loose.
• Erosion control blankets being undermined.
• Staple numbers are not adequate to anchor blankets.
• Ends not properly anchored.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 104
5.6 — Ground Stabilization
5.6.4 Riprap Slope Protection
Purpose Used at the inlets and outlets of pipe to provide stabilization of
roadway fill slope and on slopes of the channel to transition from
the pipe outlet to the natural channel. Dissipates energy of
flowing water, reduces velocity, and prevents scouring and
erosion.
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Figure 46. Riprap Slope Protection
Conditions Where ✓ When the velocities at the inlet and outlet of the pipe exceed
Practice Applies the allowable limits of an erosion control blanket with
vegetative cover.
Conditions Where
Practice Does Not
Apply
✓ When field conditions exist that will prevent the establishment
of a stable vegetative cover.
✓ Above normal high water line.
✓ May want to also consider the use of other natural stream
design devices
✓ When the anticipated velocities and natural stream require
outlet protection per 5.6.5
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page105
Construction
Maintenance
Typical Problems
5.6 — Ground Stabilization
Step 1— Place geotextile filter fabric on the slope and temporarily
anchor.
Step 2— Place riprap on slope and dress uniformly. Do not
extend riprap into bottom of stream channel. Do not use gravel,
small stone with fines or asphalt for slope protection.
• Inspect to ensure uniform coverage and stabilization has been
successful. Make repairs if necessary.
• Riprap is displaced by the force of the water.
• Erosion may occur where there is inadequate structural
control.
• Excessive amounts of riprap placed in jurisdictional areas.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 106
5.6 — Ground Stabilization
5.6.5 Riprap Outlet Protection
Purpose Where the natural streambed cannot withstand the anticipated
outlet velocities, riprap is typically used to absorb energy and
reduce velocity from the outlet flow. This prevents outlet scouring
and protects the pipe from being undermined.
Conditions Where
Practice Applies
Conditions Where
Practice Does Not
Apply
Construction
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Figure 47. Riprap Outlet Protection
✓ At pipe or culvert outlets where scour is present and is
endangering the stability of the pipe or culvert.
✓ At new pipe or culvert outlets where the natural stream bed
cannot withstand the anticipated outlet velocities and failure
will endanger the stability of the pipe or culvert.
✓ Areas must be permitted.
✓ When scouring of the natural stream will not endanger the
stability of the pipe or culvert.
✓ When scouring is not present.
• Reference Standard 876.01 and 876.02 — Roadway Standard
Drawings, Current Edition
• Riprap should typically be placed for a distance of 4 times the
pipe diameter from the outlet.
• The area in which to install a dissipater should be undercut
the thickness of the riprap such that the riprap is flush with the
channel side slopes.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Page107
Maintenance
Typical Problems
5.6 — Ground Stabilization
• Unless otherwise specified, use the following:
- Pipes < 48", use Class B riprap
- Pipes > 48", use Class I riprap
• Inspect and repair areas of erosion.
• Erosion due to inadequate riprap coverage.
• Riprap exceeds permit allowances.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 108
5.7 MAINTAINING NORMAL FLOW
Maintaining normal stream flow is critical to aquatic organisms.
Multiple barrel culverts or pipes are designed for peak flow
conditions, and during low flow conditions they may distribute
normal flow over a large cross-section. Practices such as sills
and rock vanes are installed to direct the stream flow through a
single culvert or pipe, thereby maintaining a more natural channel
condition.
5.8.1 Sills
5.8.2 Cross Vane Rock Weir
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 109
MA/NTA/N/NG NORMAL FLOW
5.7.1 Sills
Purpose Often a 6- to 12-inch high structure is placed at the upstream side
of a multiple barrel culvert to divert the stream's normal flow into a
single barrel. The goal is to maintain a similar depth and velocity
of water in the existing channel similar to the natural stream
geometry. During larger storm events, the sill is overtopped and
all of the barrels are utilized. When utilizing multiple barrel
culverts, the design of the sill should mimic the stream cross-
section.
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Figure 48. Sills
Conditions Where ✓ Streams that have a normal flow and multiple culvert barrels.
Practice Applies
Construction Step 1— Divert the normal flow into the designated barrel using
an approved temporary impervious dike.
Step 2— Construct the sill such that wet concrete does not come
into contact with the stream.
Step 3— Leave the temporary impervious dike in place long
enough to allow the concrete to cure.
Step 4— Remove the temporary impervious dike.
Maintenance • Inspect for damage.
Remove debris and sediment.
Typical Problems . Debris and sediment accumulation blocks flow and causes
premature overtopping when culvert is not properly sized to
accommodate a sill.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003 Page 110
MA/NTA/N/NG NORMAL FLOW
5.7.2 Cross Vane Rock Weir
Purpose A 6- to 12-inch high rock structure keyed into streambank with
declining surFace plane in center. Device placed just downstream
or upstream of culverts to maintain stream stability and
streamgrade. The goal is to maintain a similar depth and velocity
of water as in the existing channel. During larger storm events,
the cross vane rock weir is overtopped and the other openings
are utilized to convey water. The device should be sized and the
dimension is a function of the stream bank full dimension.
Conditions Where
Practice Applies
Construction
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Figure 49. Cross Vane Rock Weir (looking upstream)
✓ Streams that have a normal flow
✓ Existing multiple pipes and culvert barrels.
✓ Stream retrofit to improve low flow, decrease stream bank
erosion, and improve AOC.
Step 1— Divert the normal flow into the designated barrel using
an approved temporary impervious dike.
Step 2— Construct the cross vane rock weir using footer rocks.
The rocks should be uniform enough to form a solid barrier to
divert the normal flow and minor storm flows
Step 3— Remove the temporary impervious dike.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August2003 Pagelll
Maintenance
Typical Problems
5.7 — Maintaining Normal Flow
• Inspect for damage.
• Remove debris and sediment.
• Debris and sediment accumulation blocks flow and causes
premature overtopping.
North Carolina Department of Transportation
August2003
BMPs for Construction and Maintenance Activities
Page 112
I_�r»�►�17►:1
Appendix A - ACRONYMS
Appendix B— TERMS AND DEFINITIONS
Appendix C — CONTACT LIST
Appendix D — REGULATIONS 2003
Appendix E— ENVIRONMENTAL PERMITS & CERTIFICATIONS
Appendix F— PREDICTABLE PERMIT CONDITIONS
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX A —ACRONYMS
Acronyms
AECs Areas of Environmental Concern
AOP A uatic Or anism Passa e
BMP Best Mana ement Practices
CAMA Coastal Area Management Act
CRC Coastal Resources Commission
DCM North Carolina Department of Environment and Natural Resources,
Division of Coastal Mana ement
DEO Division Environmental Officer
DLR LQS North Carolina Department of Environment and Natural Resources,
Division of Land Resources, Land Qualit Section
DWQ North Carolina Department of Environment and Natural Resources,
Division of Water Qualit
E&SC Erosion and Sedimentation Control
HQW Hi h Qualit Waters
NCDOT North Carolina Department of Transportation
ORW Outstandin Resource Waters
RFOE Roadside Field Operations En ineer
SHPO State Historic Preservation Officer
SSMP State Stormwater Mana ement Pro ram
USACE United States Arm Corps of En ineers
USGS United States Geolo ical Surve
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX B —TERMS AND DEFINIT/ONS
Terms & Definitions
Areas of Environmental Designated areas within the 20 coastal counties and set rules
Concern for mana in develo ment activities within these areas.
Base Flow The portion of streamflow that is not runoff and results from
seepage of water from the ground into a channel slowly over
time. The primary source of running water in a stream during
dr weather.
Best Management Best Management Practices, or BMPs, are the host of tools
Practices that are applied to a project to prevent pollutants from
entering jurisdictional waters and to minimize any pollutant
loading. These tools include structural and non-structural
measures.
Biological Assessment Information provided by, or under the direction of the Federal
agency to determine whether the proposed action is likely to
adversel affect listed species or desi nated critical habitat.
Biological Opinion Document that includes the opinion of the Service as to
whether or not a Federal action is likely to jeopardize the
continued existence of listed species, or result in destruction
or adverse modification of desi nated critical habitat.
Candidate Species Any species for which the Service has on file sufficient
information on biological vulnerability and threat(s) to support
proposals to list them as endan ered or threatened.
Construction Activities All activities associated with building and operation of a new
transportation structure, or modifications to an existing
structure.
Critical Habitat (1) Specific areas within the geographic area occupied by a
listed species that is determined to be essential to the
conservation of the species and (2) Specific area outside of
the geographical area occupied by the species at the time of
listing, that are determined to be essential to the conservation
of the species.
Dewatering Dewatering is the practice of removing water from the
construction area. This water is considered polluted and
must be treated to remove sediment before being discharged
back into the channel.
Endangered Any species, which is in danger of extinction throughout all or
a si nificant portion of its ran e
Federal Species of Any species that are under consideration for listing as
Concern endangered or threatened for which there is insufficient
information to support listing (further biological research and
field study are needed to determine if listing is warranted).
Is likely to adversely affect: The appropriate conclusion when
a proposed acfion may pose any effects on listed species, or
designated critical habitat and the effect is not discountable,
insignificant, or beneficial. When the Federal Agency
preparing the Biological Assessment determines that a"is
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX B —TERMS AND DEFINIT/ONS
likely to adversely affecY' situation exists, then they must
initiate formal consultation.
Is not likely to adversely affect: The appropriate conclusion
when effects on listed species are expected to be
discountable, insignificant, or beneficial. A concurrence (by
the Service) with this conclusion is the termination point of an
Informal Consultation.
Jeopardize the continued existence of.� To engage in an
action that reasonably would be expected directly or indirectly
to appreciably reduce the likelihood of both the survival and
recove of a listed species.
Erosion Control Erosion control consists of ineasures taken to prevent
sediment from leaving the job site. These controls intercept,
and settle sediment from runoff before it is discharged from
the project. Erosion controls also help reduce velocity and
reduce the erosive force of runoff.
Formal Consultation If a proposed Federal action may affect a listed species,
Formal Consultation is required. Formal consultation is a
process between the Service and the Federal agency or
applicant that: determines whether a proposal Federal action
may affect the continued existence of listed species, or
results in adverse modification of designated critical habitat.
This process begins with a written request from the Federal
agency to initiate consultation. A complete initiation package
(Biological Assessment) is submitted with the request. If a
determination is made that the action is not likely to
"Jeopardize the continued existence" of a listed species, the
Consultation concludes with the issuance of a Biological
O inion and incidental take statement b the Service.
Jurisdictional Areas Waters of the United States including streams, lakes,
estuaries, and wetlands that are regulated by the federal and
state government.
Maintenance Activities All activities associated with the repair or replacement and
operation of an existing transportation structure which reflect
current design specifications and safety standards but do not
result in a change from an existing use.
May Affect The appropriate conclusion when a proposed action may
pose any effects on listed species, or designated critical
habitat. When the Federal agency preparing the Biological
Assessment determines that a"may affect" situation exists,
then the must initiate formal consultation.
Natural Channel The channel area that conveys the intermittent or year round
water from the respective drainage area.
Peak Flow The hi hest rate of flow durin a s ecified rainfall event.
Riparian Buffers Legally protected areas along jurisdictional waters such as
streams, lakes, ponds, and estuaries in certain basins.
Rip Rap Rock of varying size place to reduce or eliminate erosion
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX B —TERMS AND DEFINIT/ONS
caused b fallin rain or runnin water.
Service(s) The U.S. Fish and Wildlife (FWS) or National Marine
Fisheries Service (NMFS), or both
Take To harass, harm, pursue, hunt, shoot, wound, kill, trap,
capture, or collect, or attempt to en a e in an such conduct.
Threatened Any species, which is likely to become an endangered
species within the foreseeable future.
Watercourse Flow path through the normal channel and/or diversion that
occurs durin minor rainfall events.
Work Area The area necessary to perform the construction or operation
activity within or adjacent to jurisdictional areas. They include
but are not limited to, excavation and storage of material,
construction, and the maneuvering of equipment and
manpower.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
NCDOT CONTACTS
Contact Division for Resident Engineer, Environmental Officer, Field Operations Engineer.
DIVISION MAP
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Z
O
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I
Ci
O
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APPEND/X C —CONTACT LIST
NCDOT CONTACTS
Contact Division for Resident Engineer, Environmental Officer, Field Operations Engineer.
ORGANIZATION MAILING ADDRESS PHONE FAX
NCDOT Division of Highways 1536 Mail Service Center (919) 733-7384 (919) 733-9428
Ralei h, NC 27699-1536
NCDOT Headquarters 1501 MAIL SERVICE CENTER (919) 733-2520 (919) 733-9150
Secretary of Transportation RALEIGH NC 27699-1501
NCDOT Highway Division O1 1 l 3 Airport Drive, Suite 100 (252) 482-7977 (252) 482-8722
Edenton, NC 27932
NCDOT Highway Division 02 105 Pactolus Hwy. (NC 33) (252) 830-3490 (252) 830-3352
PO Box 1587
Greenville, NC 27835
NCDOT Highway Division 03 124 Division Drive (910) 251-5724 (910) 251-5727
W ilmington, NC 28401
NCDOT Highway Division 04 PO Box 3165 (252) 237-6164 (252) 234-6174
Wilson, NC 27895
NCDOT Highway Division OS 2612 N. Duke Street (919) 560-6851 (919) 560-3371
Durham, NC 27704
NCDOT Highway Division 06 PO Box 1150 (910) 486-1493 (910) 486-1959
Fa etteville, NC 28302
NCDOT Highway Division 07 PO Box 14996 (336) 334-3192 (336) 334-3637
1584 Yanceyville Street
Greensboro, NC 27415-4996
NCDOT Highway Division 08 902 N Sandhills Blvd, PO Box 1067 (910) 944-2344 (910) 944-5623
Aberdeen, NC 28315
NCDOT Highway Division 09 2125 Cloverdale Avenue (336) 631-1340 (336) 761-2347
Winston Salem, NC 27103
NCDOT Highway Division 10 716 W Main St. (704) 982-0101 (704) 982-3146
Albemarle, NC 28001
NCDOT Highway Division ll P O Box 250 (336) 667-9111 (336) 667-4549
North Wilkesboro, NC 28659
NCDOT Highway Division 12 P O Box 47 (704) 480-9020 (704) 480-5401
Shelby, NC 28151-0047
NCDOT Highway Division 13 PO Box 3279 (828) 251-6171 (828) 251-6394
Asheville, NC 28802
NCDOT Highway Division 14 253 Webster Road (828) 586-2141 (828) 586-4043
S lva, NC 28779
NCDOT Roadside Environmental 1557 Mail Service Center (MAIL) (919) 733-2920 (919) 733-9810
Unit Ralei h NC 27699-1557
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX C —CONTACT L/ST
United States Army Corps of Enqineers (Civil)
Re ulato Field Office MAILING ADDRESS PHONE FAX
ASHEVILLE REGULATORY 151 Patton Avenue, Room 208
FIELD OFFICE (NCDOT Asheville, North Carolina 28801- (828) 271-7980 (828) 281-8120
Divisions 10, 12, 13 & 14 5006
RALEIGH REGULATORY 6508 Falls of the Neuse Road,
FIELD OFFICE (NCDOT Suite 120 (919) 876-8441 (919) 876-5823
Divisions 5, 7, 9& 11 Ralei h, North Carolina 27615
WASHINGTON Post Office Box 1000
REGULATORY FIELD Washington, North Carolina (252) 975-1616 (252) 975-1399
OFFICE (NCDOT Divisions 2�889_1000
1,2&4
WILMINGTON Post Office Box 1890
REGULATORY FIELD Wilmington, North Carolina (910) 251-4511 (910) 251-4025
OFFICE (NCDOT Divisions 2g402-1890
3,6&8
United States Fish & Wildlife Services*
RALEIGH FIELD OFFICE SS1-F Pylon Drive (919) 856-4520 (919) 856-4556
FOR ECOLOGICAL Raleigh, NC 27636-3726
SERVICES
ASHEVILLE FIELD OFFICE 160 Zillicoa Street (828) 258-3939 (828) 258-5330
FOR ECOLOGICAL Asheville, NC 28801
SERVICES
� County list of threatened and endangered species can be found at the website http://nc-es.fws.qov
National Marine Fisheries Service
HABITAT CONSERVATION Pivers Island (252) 728-5090 (252) 728-8728
DIVISION Beaufort, NC 28516
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX C —CONTACT L/ST
NCDENR Reqional Contacts
DWQ, DLR-LQS
Re ion Offices Address Phone Fax
Interchange Building
Asheville Regional 59 Woodfin Place �82g� 251-6208 (828) 251-6452
Office Asheville, NC 28801-2482
Courier 12-59-01
Systel Building,
Fayetteville 225 Green St., Suite 714 (g10) 486-1541 (910) 486-0707
Regional Office Fayetteville, NC 28301-5094
Courier 14-56-25
Mooresville 919 North Main Street
Regional Office Mooresville, NC 28115 (704) 663-1699 (704) 663-6040
Courier 09-08-06
1628 Mail Service Center
Raleigh, NC 27699-1628
Raleigh Regional Location: (g19) 571-4700 (919) 571-4718
Office 3800 Barrett Drive
Raleigh, NC 27611
Courier 52-01-00
943 Washington Square Mall
Washington (252) 946-6481
Regional Office Washington, NC 27889 (252) 975-3716
Courier 16-04-01
Wilmington 127 Cardinal Drive Extension (g10) 395-3900 (910) 350-2004
Regional Wilmington, NC 28405
Office Courier 04-16-33
585 Waughtown Street Main
Winston-Salem �/inston-Salem, NC 27107 (336) 771-4600 i336) 771-4631
Regional Office (Courier 13-15-01) Water Quality
336 771-4630
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX C —CONTACT L/ST
Wildlife Resources Commission Contacts
Eastern Counties 1142 I-85 Service Road
Highway Project Coordinator Creedmoor, NC 27522
(919) 528-9886
Western Counties 12275 Swift Road
Highway Project Coordinator Oakboro, NC 28129
(704) 485-2384
Northern Coastal Plain NCWRC, DENR
Regional Non-Game Biologist Coordinator 943 Washingto Square Mall
Washington, NC 27889
252 946-6061 Ext. 345
Southern Coastal Plain 901 Laroque Avenue
Regional Non-Game Biologist Coordinator Kinston, NC 28501
(252) 522-9736
Eastern Piedmont 1142 I-85 Service Road
Regional Non-Game Biologist Coordinator Creedmoor, NC 27522
(919) 528-9886
Western Piedmont 3855 Idlewild Road
Regional Non-Game Biologist Coordinator Kernersville, NC 27284
(336) 769-9453
Mountain 20830 Great Smoky Mountain Expressway
Regional Non-Game Biologist Coordinator Waynesville, NC 28786
828 452-2546
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
Beaufort
Bertie
Brunswick
Camden
Carteret
Chowan
Craven
Currituck
Dare
Gates
Hertford
Hyde
New Hanover
Onslow
Pamlico
Pasquotank
Pender
Perquimans
Tyrrell
Washington
North Carolina Department of Transportation
August 2003
APPENDIX C -CONTACT L/ST
CAMA COUNTIES
BMPs for Construction and Maintenance Activities
APPEND/X C —CONTACT LIST
CAMA CONTACTS
OFFICE ADDRESS PHONE FAX
Raleigh Central Office 1638 Mail Service Center �g19) 733-2293 (919) 733-1495
Raleigh, NC 27699-1638
Elizabeth City District
Serves: Camden, 1367 U.S. 17 South �252) 264-3901 (252) 264-3723
Chowan, Currituck, Elizabeth City, NC 27909
Dare, Gates,
Pasquotank and
Perquimans counties
Morehead City District
151-B Hwy. 24
Serves: Carteret, Hestron Plaza II (252) 808-2808 (252) 247-3330
Craven, Pamlico Morehead City, NC
counties and Onslow 28557
County south to New
River
Washington District
943 Washington Square
Serves: Beaufort, Bertie, Mall (252) 946-6481 (252) 948-0478
Hertford, Hyde, Tyrrell Washington, NC 27889
and Washington
counties
Wilmington District
Serves: Brunswick, New 127 Cardinal Drive Ext.
Hanover, Pender Wilmington, NC 28405- (910) 395-3900 (910) 350-2004
counties, and Onslow 3845
County north to New
River
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX C -CONTACT L/ST
NORTH CAROLINA TROUT WATERS
(Named West to East)
Cherokee Yancey Wilkes
Graham Mitchell Surry
Clay McDowell Stokes
Macon RutherFord
Swain Polk
Jackson Burke
Haywood Caldwell
Transylvania Avery
Henderson Watauga
Buncombe Ashe
Madison Allegany
North Carolina Department of Transportation
August 2003
BMPs for Construction and Maintenance Activities
APPENDIX D —REGULATIONS 2003
Regulations
Clean Water Act In 1972, Congress enacted the first comprehensive national
clean water legislation in response to growing public concern
for serious and widespread water pollution. The Clean Water
Act is the primary federal law that protects our nation's
waters, including lakes, rivers, aquifers and coastal areas.
The Clean Water Act's primary objective is to restore and
maintain the integrity of the nation's waters. This objective
translates into two fundamental national goals:
To eliminate the discharge of pollutants into the
nation's waters, and
To achieve water quality levels that are fishable and
swimmable.
Section 404 Section 404 of the Clean Water Act establishes a program to
regulate the discharge of dredged and fill material into waters
of the United States, including wetlands (waters of the
U.S. are referred to as jurisdictional waters in this
manual). Activities in jurisdictional waters that are regulated
under this program include fills for development, water
resource projects (such as dams and levees), infrastructure
development (such as highways and airports), and
conversion of wetlands to uplands for agriculture and forestry.
The basic premise of the program is that no discharge of
dredged or fill material can be permitted if a practicable
alternative exists that is less damaging to the aquatic
environment or if the jurisdictional waters would be
significantly degraded. In other words, when you apply for a
permit, you must show that you have
Taken steps to avoid wetland impacts where practicable,
Minimized potential impacts to wetlands, and
Provided compensation for any remaining, unavoidable
impacts through activities to restore or create wetlands.
A permit review process controls regulated activities. An
individual permit is usually required for potentially significant
impacts. However, for most discharges that will have only
minimal adverse effects, The United States Army Corps of
Engineers (USACE) has established nationwide general
permits and some specific regional general permits, which
allow an activity under specific conditions.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX D —REGULATIONS 2003
If the USACE determines that a 404 Permit is required
because the proposed project involves impacts to
jurisdictional waters, then a 401 Water Quality Certification is
also required. In North Carolina, a single form is used to
request both a 404 Permit and 401 Certification.
Section 401 Section 401 of the Clean Water Act delegates authority to the
states to issue a 401 Water Quality Certification for all
projects that require a Federal Permit (such as a Section 404
Permit). The "401" is essentially a verification by the state
Division of Water Quality (DWQ) that a given project will not
degrade jurisdictional waters or otherwise violate water
quality standards.
Endangered Species Act Applicability: Applies to all NCDOT projects that have a
(ESA) Section 7 federal involvement including FHWA funded projects, or
Interagency Cooperation projects requiring a federal permit such as an Army Corps of
Engineers permit.
Requirements: Section 7 of the ESA requires every Federal
agency to insure any action it authorizes, funds, or carries out
"is not likely to jeopardize the continued existence of any
listed species or results in the destruction or adverse
modification of designated critical habitat."
Procedures: The procedural regulations governing
interagency cooperation (consultation process) under Section
7 of the ESA were established by a joint rule (50 CFR Part
402) between the U.S. Fish and Wildlife Service (Service)
and the National Marine Fisheries Service (NMFS) on June 3,
1986.
Protocol for Division Projects Performed by NCDOT Division
Environmental Officer
Determine presence/absence of listed species in a
project area
o Review NC Natural Heritage Program
database of rare species to determine
presence. If not present in database, conduct
specific on-site habitat evaluation to confirm
absence.
o Habitat evaluation: consult with USFWS or
NCWRC representative for latest information
o Conduct specific surveys for plants during
identified flowering periods. All surveys (plant
and animals) should be conducted by the
appropriate personnel.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX D —REGULATIONS 2003
• Evaluate and Document Project Impacts
o Avoidance/Minimization/Offset Impacts
o Direct Impacts
o Secondary Impacts
o Cumulative Impacts
Determination of Affect
o No Effect — no written concurrence needed (no
suitable habitat, no individuals observed)
o Not Likely to Adversely Affect — written
concurrence from the Service required
(suitable habitat in the impact area but no
individuals observed or species may be
present but project as proposed is not
expected to result in adverse impact to species
or critical habitat)
o May Affect — may require formal consultation if
effects cannot be avoided or minimized
(individuals or critical habitat affected).
Maintain Documentation
o Maintain adequate documentation in terms of
GIS screening, maps, correspondence, and
photographs in a permanent record.
o Provide documentation in the event of
individual request or audit of programmatic
projects.
o Document negative findings as well as positive
findings. Explain how conclusions were
reached for either scenario.
Emergency Protocols: Requirements of the Endangered
Species Act are still applicable. Appropriate NCDOT
representative should immediately contact local USFWS
representative to initiate appropriate coordination/con-
sultation.
Coastal Area Management In 1972, Congress passed the Coastal Zone Management
Act Act, which encouraged states to keep our coasts healthy by
establishing programs to manage, protect and promote our
country's fragile coastal resources. Two years later, the
North Carolina General Assembly passed the landmark
Coastal Area Management Act, known as CAMA. As a part
of this program, the Coastal Resources Commission (CRC)
designated "Areas of Environmental Concern" (AECs) within
the 20 coastal counties and set rules for managing
development activities within these areas. Section 103(5)(b)
of CAMA exempts road maintenance within a public right-of-
way.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003
APPENDIX D —REGULATIONS 2003
Sedimentation Pollution North Carolina General Statute 113A, Article 4 was
Control Act promulgated in 1973 to establish minimum mandatory
controls for sedimentation from land disturbing activities. The
Division of Land Resources (DLR) implements the Erosion
and Sediment Control (E/SC) Program which requires
approval of erosion and sediment control plans for all
development activities disturbing one acre or more. DLR has
delegated NCDOT authority for the NCDOT E/SC Program.
The State E/SC program may also be delegated to local
governments.
State Stormwater The State Stormwater Management Program (SSMP) was
Management Program established in the late 1980's and is implemented through the
North Carolina Division or Environment and Natural
Resources, Division of Water Quality Regional Offices. A
permit is required for development activities that require
either an Erosion and Sediment Control Plan (for
disturbances of one or more acres) or a CAMA major permit
within one or both of the following areas:
The twenty North Carolina coastal counties, and/or
development activities draining to Outstanding Resource
Waters (ORW), High Quality Waters (HQW), Trout Waters, or
Water Supply Watersheds.
The SSMP requires protection of these sensitive waters
through the use of BMPs designed to minimize the impacts of
development activities on water quality (e.g., wet detention
ponds, low-density development, etc.).
Basinwide Stream Buffers Since the late 1990's, the DWQ has established several
major river basinwide programs that require protected buffers
along jurisdictional waters of the State (as shown on soil
surveys, USGS topo maps or by field determination) such as
streams, lakes, ponds and estuaries. Typically, a 50-foot
wide vegetative band along each side of the water body is
protected from development activities. The buffer is usually
measured from the top of the bank or the Mean High Water
line. Existing drainage ditches and roadside ditches are
typically exempt from the buffer rules provided that they are
managed to minimize the amount of sediment, nutrients and
other pollution that enters jurisdictional waters. New ditches
are allowable if stormwater management is provided.
Excavation of streambeds usually require authorization from
the appropriate state agency. Prior to 2002, buffer protection
rules were established in the Neuse River Basin, the Tar-
Pamlico River Basin, the Catawba River Basin, and the
Randleman Reservoir Watershed. Additional State
basinwide buffer programs may be developed in the future or
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APPENDIX D —REGULATIONS 2003
may already be in place.
CAMA Buffers Coastal shoreline rules require a 30-foot buffer for new
development along coastal shorelines in the 20 counties
governed by the Coastal Area Management Act. The buffer is
measured landward from the normal high water or normal
water level. The rules apply to all navigable waterways in the
coastal counties, including upstream public trust shorelines.
In some cases, large drainage ditches could be determined to
be navigable. The buffer requirement does not apply to the
oceanfront, which already has its own setback requirements.
Local Buffers Local stream buffer programs may be established by cities,
towns, counties or other public entities. These requirements
may be more stringent than state buffer requirements.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
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APPENDIX E— ENV/RONMENTAL PERM/TS & CERT/F/CAT/ONS 2003
Environmental Permits and Certifications
401 General Certifications The Division of Water Quality (DWQ) issues general
certifications that correspond to the Nationwide 404 permits
listed below. All conditions of the Nationwide 404 permits
and General Certification must be followed throughout
construction and maintenance of projects authorized under
the General Certification. The activities and measures
described in this manual are consistent with the conditions in
the Nationwide 404 permits and the State's General
Certification conditions. It is the Contractor's or Construction
Supervisor's responsibility to know of any special conditions
identified for a specific project.
404 General Permit No. 31: This general permit is issued by the Wilmington District
NCDOT Bridges United States Army Corps of Engineers (USACE) specifically
for the North Carolina Department of Transportation or other
institutions charged with the construction and maintenance of
public transportation infrastructure projects. This permit
authorizes repair and replacement of bridges and culverts
following natural disaster events. This general permit
identifies general and specific conditions that must be
followed in order for the permit to be applicable.
Requires corresponding DWQ General Certification 3404.
404 Nationwide Permit No. This permit authorizes the minimal impact repair,
3: Maintenance replacement, or rehabilitation of any previously authorized
structure or fill that does not qualify for the Section 404(f)
exemption for maintenance.
Requires corresponding DWQ General Certification 3376.
404 Nationwide Permit No. This permit authorizes the construction, maintenance and
12: Utility Line Discharges repair of utility lines and associated facilities.
Requires corresponding DWQ General Certification 3374.
404 Nationwide Permit No. This permit authorizes bank stabilization activities necessary
13: Bank Stabilization for erosion prevention. This permit may not be used for the
channelization of jurisdictional waters.
Requires corresponding DWQ General Certification 3399.
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APPENDIX E— ENV/RONMENTAL PERM/TS & CERT/F/CAT/ONS 2003
404 Nationwide Permit No. This permit authorizes activities for the construction,
14: Road Crossings expansion, modification or improvement of linear
transportation crossings (e.g. highways, railways, trails, etc.)
in jurisdictional waters, and is subject to specific acreage and
linear limits. Authorization for public linear transportation
projects in non-tidal waters, excluding non-tidal wetlands
adjacent to tidal waters, is provided if the discharge does not
cause the loss of greater than 1/2 acre of jurisdictional
waters. Authorization for public linear transportation projects
in tidal waters or non-tidal wetlands adjacent to tidal waters is
provided if the discharge does not cause the loss of greater
than 1/3 acre of jurisdictional waters and the length of fill for
the crossing does not exceed 200 linear feet.
Requires corresponding DWQ General Certification 3404.
404 Nationwide Permit No. This permit authorizes discharges of dredged or fill material
18: Minor Discharges into all jurisdictional waters, provided that the activity meets
specific criteria including (a) the discharge and the volume of
the excavated area does not exceed 25 cubic yards below
the high water line, (b) the discharge, including excavated
areas, will not cause the loss of more than 1/10 acre of a
special aquatic site, including wetlands and (c) the discharge
is part of a single and complete project and is not placed for
the purpose of stream diversion.
Requires corresponding DWQ General Certification 3402.
404 Nationwide Permit No. This permit authorizes activities undertaken, assisted,
23: Approved Categorical authorized, regulated, funded or financed, in whole or in part,
Exclusions by a federal agency or department where that agency or
department has determined that the activity, work or
discharge is categorically excluded from environmental
documentation because it is included within a category of
actions which neither individually nor cumulatively have a
significant effect on the human environment.
Requires corresponding DWQ General Certification 3403.
404 Nationwide Permit No. This permit authorizes activities in jurisdictional waters
27: Wetland and Riparian associated with the restoration of former waters, the
Restoration and Creation enhancement or creation of degraded tidal and non-tidal
wetlands and riparian areas, and the restoration and
enhancement of non-tidal streams and non-tidal open water
areas. This permit does not authorize stream channelization
or conversion of natural wetlands to another use.
Activities authorized by this permit include, but are not limited
to, the removal of accumulated sediments; the installation,
removal and maintenance of small water control structures,
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dikes and berms; the installation of current deflectors, the
enhancement, creation or restoration of pool and riffle stream
structure; the backfilling of artificial channels and drainage
ditches; activities needed to reestablish vegetation; and other
related activities.
Requires corresponding DWQ General Certification 3399.
404 Nationwide Permit No. This permit authorizes temporary structures, work and
33: Temporary discharges necessary for construction activities, access fills,
Construction, Access and or dewatering of construction sites.
Dewatering
Requires corresponding DWQ General Certification 3366.
CAMA General Permit This permit authorizes demolition, removal, and replacement
(07H.2300) of existing bridges and culverts spanning no more than 250
feet of estuarine water, public trust area, and coastal wetland
AECs and has threshold limits for AEC and wetland impacts.
This permit does not authorize temporary fill causeways or
temporary bridges associated with bridge replacements.
CAMA Dredge and Fill Under General Statute 113-229, a dredge and fill permit must
Permits be obtained before any excavation or filling project is begun
in any estuarine waters, tidelands, marshlands, or State-
owned lakes. Emergency permits may be issued when life or
structural property is in imminent danger as a result of rapid
recent erosion or sudden failure of a man-made structure.
Isolated Wetlands Permit Isolated wetlands, which are not claimed by the USACE, are
under the jurisdiction of the DWQ. The DWQ issues an
Isolated Wetlands Permit following public review of the
proposed work.
State Stormwater The DWQ issues this permit for development activities in the
Management Permit 20 coastal CAMA counties. The permit specifies stormwater
runoff controls for projects that require a CAMA Major Permit
or an approved Erosion and Sediment Control Plan.
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
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APPENDIX F— PREDICTABLE PERMIT CONDITIONS
Predictable Permit Conditions
Environmental permits typically include special conditions to ensure that impacts to the aquatic
environment are minimal. Some of the more common conditions are included in this appendix.
However, this list is not inclusive. The permittee must read, understand, and comply with all of the
permit conditions that are associated with each maintenance and construction activity.
Proper Maintenance
Any structure or fill authorized shall be properly maintained,
including maintenance to ensure public safety.
Soil and Erosion Controls Appropriate soil erosion and sediment controls must be
used and maintained in effective operating condition
during construction, and all exposed soil and other fills as
well as any work below the ordinary high water mark or
high tide line, must be permanently stabilized at the
earliest practicable date. Permittees are encouraged to
perform work within waters of the United States during
periods of low-flow or no-flow.
All sediment and erosion control measures placed in
wetlands and waters shall be removed and the original
grade restored within two months after the project is
permanently stabilized.
Aquatic Life Movements No activity may substantially disrupt the necessary life-
cycle movements of those species of aquatic life
indigenous to the waterbody, including those species that
normally migrate through the area, unless the activity's
primary purpose is to impound water. Culverts placed in
streams must be installed to maintain low flow conditions.
Equipment
Heavy equipment working in wetlands must be placed on
mats, or other measures must be taken to minimize soil
disturbance.
Endangered Species No activity is authorized under any NWP which is likely to
jeopardize the continued existence of a threatened or
endangered species or a species proposed for such
designation, as identified under the Federal Endangered
Species Act (ESA), or which will destroy or adversely
modify the critical habitat of such species.
Historic Properties No activity that may affect historic properties listed, or
eligible for listing, in the National Register of Historic Places
is authorized, until the District Engineer has complied with
the provisions of 33 CFR part 325, Appendix C. The
prospective permittee must notify the District Engineer if
the authorized activity may affect any historic properties
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APPENDIX F— PREDICTABLE PERMIT CONDITIONS
listed, determined to be eligible, or which the prospective
permittee has reason to believe may be eligible for listing
on the National Register of Historic Places, and shall not
begin the activity until notified by the District Engineer that
the requirements of the National Historic Preservation Act
have been satisfied and that the requirements of the
National Historic Preservation Act have been satisfied and
that the activity is authorized.
Anadromous Fish Spawning Discharges into Waters of the United States designated by
Areas either the N. C. Division of Marine Fisheries (NCDMF) or
the N. C. Wildlife Resources Commission (NCWRC) as
anadromous fish spawning area, are prohibited during the
period between February 15 and June 30, without prior
written approval form NCDMF or NCWRC and the Corps.
Sturgeon Spawning Discharges into Waters of the United States designated as
sturgeon spawning areas are prohibited during the period
between Feb. 1 and June 30, without approval from the
National Marine Fisheries Service (NMFS).
High Quality Waters Outstanding Resource Waters, High Quality Waters, Inland
Primary Nursery Areas, Contiguous Wetlands, and Primary
Nursery Areas.
Areas of Environmental Area of Environmental Concern (AEC) in the twenty (20)
Concern coastal counties of Eastern North Carolina covered by the
N.C. Carolina Coastal Area Management Act (CAMA),
must also obtain the required CAMA permit.
Trout Waters Prior to the use of any NWP in Mountain Trout Waters
within twenty-five (25) designated counties of North
Carolina, applicants must comply with NWP 13. The
applicant shall furnish a written statement of compliance
with all of the conditions listed in the applicable NWP.
Notification will include a letter of comments and
recommendations from the North Carolina Wildlife
Resources Commission (NCWRC), the location of work, a
delineation of wetlands, a discussion of alternatives to
working in the Mountain Trout Waters, why other
alternatives were not selected, and a plan to provide
compensatory mitigation for all unavoidable adverse
impacts to the Mountain Trout Waters.
Riparian Buffer Protection Impacts to any stream length in the Neuse, Tar-Pamilico,
Rules Randleman and Catawba River Basins (or any other river
basins with Riparian Area Protection Rules [Buffer Rules]),
requires written concurrence from DWQ in accordance with
15A NCAC 2B.0200. Activities listed as "exempt" from
these rules do not need to apply for written concurrence.
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APPENDIX F— PREDICTABLE PERMIT CONDITIONS
Concrete in Water Measures will be taken to prevent live or fresh concrete,
including bags of uncured concrete, from coming into
contact with waters of the state until the concrete has
hardened.
Riprap Bank Stabilization Filter cloth must be placed underneath riprap used for
streambank stabilization.
Pipe/Culvert Installation Installation shall be in a manner to promote the safe
passage of fish and other aquatic organisms. All culverts
in the 20 CAMA coastal counties must be buried to a depth
of one foot below the bed of the stream or wetland. The
dimension, pattern, and profile of the stream, (above and
below a pipe or culvert), should not be modified by
widening the stream channel or by reducing the depth of
the stream. Culvert inverts will be buried at least one foot
below the bed of the stream for culverts 48 inches in
diameter. For culverts 48 inches in diameter or smaller,
culverts must be buried below the bed of the stream to a
depth equal to or greater than 20 percent of the diameter of
the culvert.
Steam Relocations
North Carolina Department of Transportation
August 2003
Natural channel design must be applied to the maximum
extent practicable for stream relocations.
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Additional copies of this manual or further questions should be addressed to:
Ken Pace, PE
Roadside Environmental Unit
Operation Section
NC Department of Transportation
1557 Mail Service Center
Raleigh, NC 27699-1557
Phone: (919) 733-2920
North Carolina Department of Transportation BMPs for Construction and Maintenance Activities
August 2003