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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 � , :, ' ;' ;,� ,},�l . ; �� ++ t+,. r _.,._ . Section 1.0 -Background Information Nerrth Cuolina De��artn�ei�t uETr>nispoataciur� j / �� ZU -LL 2 � �Z� S � � � 'L% �L `L !% �fi � North Carolina Department of Transportation August2003 Tf�c mission c�f thc Nocd� C=uolina Lkpar[mrnr ot 1'ransp���tat�on is to pr�-,vidc u,� liltcgratcd rransE�:�rtati�ri �-��str�n �hat rn}t.u�ccs thc sratcs well Lxin€. i?ur gnal is to �rnvidc a satr a�d wcll-rc,ain�ained rrans�ictativn sysicm chat mcc� thc nced< <�t out �ustnrr�as an� cup�tts che �•cln�,mrnt nfsuctalnal�lc, vlbrant CUIT�[1tW11[1C'. IIl SC> duin�, we:ue c�unmitte.i tu pla�nin�. clesigning, .nnstrucn��, rnainta�n�ng az��i man:�ir�� an tntercon�ucce� v:u�s�+urtatirrn sysrem whilt strivir�� tt� pre:cenm and rnhance ouc n�tural arid .ultural resuiu�es. Envirnnmenral steucar�hip encamEra4ses �h�e ccsPunsihiliries and is reftectcvi in uut daytu-day operatlnns by: • Sa�cg,�ac�ing thr �ubl'ic's hc�lth l�y cnndutrtiag ouz buSinas In an cnvirunmcncally r�pnn�iMlc �nan�cs • L)cmurotrating uur cur f�c and commltmrnt tn thc cr�v7rocimrnz Feco�nizin� tlixt csuc �uet+�nicrs a�ect us t� pmvidc mobil'iry and a.�ualit3 nt lifc tli:a� iucfuiio the �rotc�:tiou at �he nuural resni�rccs an�� ch< <-�ilnu�l and so:ial valu�s of tl�rir cuniniunitv. Fa.h em�4c�yec is res�,��nsible Evr trra�r��?ratin� thcic ptln:iplo c�f safcty, rnviconmcraral stevrudship and custamer for�� into thclr daily �tivitics. .�,pE�cove� Ln� the Boud of Teu►sportaue,n c�n Febru�ry %. 2G��12. � �� � / � �` l� i � ��_ . � ! .�/ ., ! �, , ,. BMPs for Construction and Maintenance Activities Page 5 THIS PAGE WAS INTENTIONALLY LEFT BLANK 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 ' ���� ���,�. �,` \ � ¢ y_ _.ty` �� � r #K ""� � � � � r - � . � 'r'P ��•� � Y �.� ; * � � � ��-._� ._ � � � � � ~ ���h � x �_�A � ::, w. . . r — _ , .+r - . - �c �x�, ,� .� 4 � - - _ . . � „�., '�' ' `� . " - � '�F, � +�,'., : - Ar �� � �:. � � �� . .� � <;, �.; , . ,�t_.: , _ �� y � � .. t �c ji< —�- � ; �� - _ '� _ .�-'?�'e='��;e�.� � � F .,,� ��x �%' ;"' � --_ . _ ' _ ��ii�. _ y� � .t' �__r .r. ' �3. =' �.. _ Figure 3. Riparian Buffer • 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. , .� .p .;: o-- `� � '.1� �A �. f { t; 1 �: � ��,, ������ _' I� __ _ e ��': . � I �v d .�:. ` � c �' +./� - f�T�^ `'�— , - _ _ _. � � � u .: r - �� � A�" e�'�:' �'� � �� �i'��,.� ' 1i � �� a �'��: :S. .� T'�� � .. ,. r �r` � YS-�f°`�v �'�arsP -�, �,s.l�r '�- r J ,. s s w `y� �l ,,rt�i� d��k; � � ��. 1� � k 7 � ': �x, i �,. . �'. t `. �..: k r ».���. '� � c�..: r i' k �" � ,t�a1s� ` .S4 \'" d y' �r,�y, � "r' `¢ .'.%�k, s7 J2 �, ✓ :i�ii�'�• e � `l� _ .�.7LJ�it 3�i1.i`iFE�..�_'.� 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. �� ' � ;�r �,� � r � , y F"� 7� M y ��.'-� � . 4 �r ��` `�q�:a�� �`:'l� ��. .� �� ' � •+.Ry�Tof .:'�„��_., T�r k� + �' .. - '+.. �. w ..� . " _. _ . . 4 ._ _ '"' x. . ' .. _ . a/L�•i �' ,_ " 4 � � ` � +� r �. �•� .-a, � � - � � �� � � ' � '��Cd ��' �.�' ` : � `-,-�-��- ���:, e u �-. �� � _ �x , . .� �. �,s� ��' z�r"�4,s +• i : ! , � � y y y�,y.� �y }�t �„*�'r� r '��� ' . t ' � .� ' rt�`Y'"?��.�'' + � r' � , �� , i � .�, .: � -� �i,: '.,k•' ���� y�'�`,�,. �.� _ _ i U�� >(b-, .,���, "}fj.. �': � �� < . ., r ��r — r/ �' . i - -.. r� l. .�1C �.i 1." �n� \ , �+�`../lp_'"-S� �Q �r :,{� I �r , �F��r'�i A�y� � ;t� ���t v�' i ,�_.,:� rE�� - � �,<: �w ,:,e� �, � r4 '�s _ _ �i�"" `�, :r f`� c� R . �� ; � ��,a� } ,��� , �� x�',:. q� t��� t' �r.'r�� r ..1,��t1 ` . ti�� z � P�` �.. _ �� 5 _ h t� y��� ;'� S _ i � . ,�.i - � • �{� � "4 3 N:� V �.�,,•,`j'�-�` .��+s� _.,`l � � � .. �.�' r �,-i + ,�'- , ',�L-..?,..�.;` �.., . _ � � �, : f.4 � � . _.. ' i�- -' � j�' r{ '- ;. �� , � ,� r \ 7�• � 7' 1 t`= i� � A,� ~,' �`t �y+`�.L'�{ � r � �.� : > �'fr �K�'''�'w�^'�{.. r � . . . :..� Yk. •r ��� � iqlr,i y'i,'t"- � . „ /� � .���, 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. , � ;� .;;: : ; �_.���.�-__�_��... ____-��w_._.__,--__ ,��_��<<__�_��-- y" �T'�:�.�►, `_� y_ � � =' - f �' � �� -s,,,,. ° . � , � �. , -s� �- ,'` r � '�r • a : s .� w..,,�,. � „ " ': '- „ �..��.. r y �,��. t r,y{ •' 2}, � ....- - � � `�y' ;r�� J'� ' �`..�-� 9 �+�''�`��.�.0 '�ii+� ° ��.��t 1-}� /ri s� ���l� � � �. . 'r �J,!��� �y _ `s��4 r,�. ��� �.� -..��:4�' __ � .9 � y�Y �t A � j'�s ��� '�,."ty . -� -� � . � �f < � ' _ _ ' _ ; yy' . \ � � i " . �'11.,• r . �.,�� -�= . ` '''`+.. - ... , ,.. _, - v: -- ���_��„� F'��l� �,�Ji ': �-�`�!�`=��'� �' :�,_ , .,�: _. _ 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. � .,� �.: ��..� " �- . _ , ;��=..,� � � � � � � T ' � � 'l �' y a I.� � North Carolina Department of Transportation August2003 ��'� �f ��c r: `��;��; > � _.,_-4-, ,; � -� ~ •, „r ;' +'��'' ' ` � �=��� � �, :� y aFl � W . 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. �a -:, r r }` ,� `; �eY f � � � � * �� : I 1 �`. �� � ~ I I I � , �.. � �� � . 'I I : � 1 � i � I r_ , �� � I ' � � � � � -r'_� - _ t • - { ; i� � i�+-' . , _ ' ` ����q �� � �I C � y J J `' ak i . i ; � , �I ' w 'w �' -� _ � a. � �:�. .?'_�. r � i �. . : �- ,� � - . , %� � -. .�. r �. � — - :�.� � ; �2,. ,� ;�:;. �.�- _ - '�!� ,y � ' � �- - .::'�b�Y ,�� , �'.�s� �a _.� ��'�� - . �� � ` � � . . —��-�x�*��1:: is� s'^�'' .`, � , ___..-�--v-�-' _ ,_.,:. „�--�. � � '� � ti ` •..r.----<-^- , � 1;� f� � "i � ..�` 4�'���i� ��- '` � -���, � � 1 .,g ��. . ' , . . ' �tt : .'°?��a�`�..�..�o.� !T; . ?}�,: �: - � . - , '���ca'`.'.k�1�'� - � �.'.. . ,\ '� . •,-± � `r \i � . ``' �w'1�\�ri �� Figure 11 ,����' --.."...+ �� ' - � '` �� '2' � c ;r�''� �>. ,� �� - 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 ;. � �,~ °"_ �-a-- - . , "-r% ���' --'� ''� e�.� - ::�. '9., . ' ' 4 �'�. �� �` ^ � ti;. . �, �` � � �:_:,. f�,l_.x'� � �: — �,I• ��. � ���' � 1 � .i� � � � �.� - � _: �� ��� _ � : '�..I �� .�ri �S' "_ ' � .�. _ � , .. Il+���, .'�;;'t � _ s. ":i�+hj�.:,--..��z-I ,1 Ijl:'.', ,� . , ' �'""�� _ . � � .. �� _ � .x�' xV. i � "1s � 4aM -. �- : y .,. � ,,: ..�i,,: �� }; � r ,�YO�,a;,j� 'i ..� . • . w: . ; .. :� _ �_ ' � S r. .':�t3 : � �'f�'�.✓� � i1 � , � , %I :�_��� � .{1['1. �' � . . � ti .. � fi . • Y I .� � . �..�+� � , o � � . . �� � , � .1�I � . :♦ � � •�.��� �� t � s � :2'+r' : `s � ��• a y� ` `� ; `� ��:t'� „j � "Y '',,e?.....� . �i��`I, ���j l 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. ��'.....� ..� �. �r ,.;�_>:-r,;, . - _ :_�;� - � �� �' �'. � � _ . �. , -_- �, ,,�,t'' : I' J � ��� 1 �� r . _ u ,�. , ; � ' Y r ` `i. . a _ �: � ` ' : �`a�p € ,�i,a � � x�. � �,,� ti v, ' . �.� �� � ' �`, ? � � � T y�� � �' _ 1 � a v• � _t�.r�r' ,� 'y* . '' <� .-h �.�; � ,\ 4"�, , 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. Y�t1�, ; 1 �' � � i 1 Y. �•- �� �-��.��•�� � ,`��, � � �i ,- _ � Tr �,� � � !,ty� . �� � .,, 3a^��;c t o �s � '!�r . .�9AAi7"> �Y�'��t, . . r � � �� .. i� ��- :'v:e1"'i�i`�`„ Y�'.�J � . � c.,Ig• a �^:, \� L' Y - . `�. g �t, ? ";' �.�.;�,,}..a.w' ar - _ �.� q� �F� �- . : � ` ,.-_ s ,_. e :�t'' `\ .. z b',�i .'1. �'4' ; � . •:�. ,.,� i:_ ;-�; _ ' ^. .. ' . - . . , . �. ,�. ' � ` � A .}� \� � �� ".,�' ' -'nG. L: K yf"c `' �t. 1 A'; j'y'�t. s` - �- .�,,�. r -.�.,- � - �. _ : �,r ',H_ . . j .t' .,�: �� ' �� L -� ' �r'�J- .., � � _. _�� .�' � '': � _ ' ` \ , ,�,. %4, . , �_ ` .,. _ y �"�f,, � � ,� ` - `�� ,� . �'� ��„ -- t ._, - y. `. -�,.0 � � - . �� � t iy ' , � �L� y � , j-.���� � � r,.y+' �*�� y � ���k+a �+e� :� � SF�,S.' `' ; , � .. . kt r n�j'� +n ' t <IJ i'�.. . . � � �� ; �' � �,��� � . .iix- �'.' r '�__ `�+ 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 4 _ _T � _ 1. . " �A ._ "` ' i p _- ` �i.Ti��"r" .��.� �.�'� '� . '�i,-r r r � �' ''��� :i`_• - � 'rer,..y,^ t '� �� �t: , _ . . . � ,�,_ . '' ' = s: �— - �, _ `� r , " � v � k.- � � ; fk . � �� . � I , � �p,: � � �.E * '�r� �� . • .. �, . w s a'�':'r + y' , V.' � . ar,% � 'y Y.� e ,,�1�- _���'Y - V �'�'�� �� � �'`� ��� �`� ,�y�y.��d` �_ �4 a i i�a; � :,f t� � � :=� � �.; *�, r � OJ�rFF�^-r., �b<+�r . _ . r "L` �� r�, -LY�' � ,;s s • t: .~ .ai r ,�, -- � .:: �.: s _. . � "„� � ?' 16 � ' r r �� � ' �-�'�. � '� -, .r.�. . y.'" �.. , � 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. �L?�4=_'_'- _;e� ��' ��l�=�.-�. � . _ �� ' �� - � � _ r : �. � � � �-'�� • � - � �,y � w�-.:��;�,� ':`� � _ � � '�i b;ra� �f•.��� : a r . �.3'�. �,i, '� :� •� � ,� � �a � � - ' � �rr � '�� aF�,, •r A �� � . ..'� � : - 3; _.,� c• ��.. , ,.�_r : - _`� � � � f E ` 4 �y',�"�--�"�F'+�`� s��""� � � `' c . ";y� } � _ ���� I �k`�J��-•-5`+� 'F,y"�- "� ��3f'J '� T�- � � �.�' .- � k� � f �4 �y���. .� . V Ci, ' . � : � �`:�d 4t �y q _. j ' . _ . +l1' ..:j/�,�.��. �� ,�` .�-� t - -�' ; : c�'�.- ;' .�.:L'' r� ' � �o := � �. L''� J3 e'' 4� L�,� f� ,C --.r�, _. � ,._�.� ; ,,, _ .�.� T�� �, � � ,� T� �,. r,.'�:^ -� , �- _L. _ .y;�-�. �,�" � . � .� �#� . - . �, � .� � .i�a�. '.�`Y q j . ) �-�� i � r +, y � i, � �S: � y' �' � �s ��� ���- � � , . :'-� ,�, �� � � � � . - fy -. � . % � �{Y �Srt4w�`��. �����tr- �� �.���ZR�t�.� 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. , . ,�,+���.,,�;, ���` -� ' -- `-►�--�-� .. _ _ - — ; x�"��`� ;� = z- -�i�.•� - �.'_'� ..��. '- -.. . �_� � - � ` - ' g�r_.�,���.. . � �'� - , _ �Q- _ _ - y _. . ''-+�F�"`�- . �1"".' -�,..} :'���-s�x� '�.s� �R4" r _ � �� ���� � � 1�� �� � �, er[ r� ,� `Y���: � " " { '" �� " '�{`, C 'I� i►l� ..> � t",! f � �� � . '���' �' . � ie� 'V. .!F_ '^� �: ,�' -. ' �I�� :,�` • �, � ._�a��:.: � ;. �- �. -.. ;-. tt : -- ¢ �-� � 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. *`--� �'-`�- `'',�`��, = f's� +: - *.c��• �' � �'! ' � �'_` � �`��°�'� � � 3 �y� � b . � �'� �r�-�- , � �` �: � �� ' ��1 �� � ��•� f�� �,t_ -+. ..�y J� . ������� � a�. �3 � J E ;' y_. � � ���?'� �.-_,F.e-^� �r � c 3 ' _'Z.. � 1 V-J•: � .Ei6 �y-,�g�, . a 3 �t . w� l / C ` hT1 �r,� J � �:M' `a��S`� ' � f , . . . . . . jSY� 3 `� £�'ry � � r�.. ,� - �i.�� ��� ' i � '� L+ _'t . j } . _ �► �. . ` _ ~ ��t� �� _ ' ���j' _ �� '__—"'��,'�� � _:FA ���,-� . . ����y/��- ��lw�^ - :'^ . ` . -�;y _► ,, �`'_. .� #' � �_ ��r �?�_' `������ � � Figure 29. Temporary Rock Sediment Dam Type "B" 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 � N�IA►N14GIN� �i�l� Wia►fi�R��C��R��: I�YP�ISS PI�MPING ENSURE TC} ANCHOR ALL Y rv, �" �,�•�. , PUMPS AND PIP��B SECi1RELY. NC}RTki CARO�f�A �EPAFtTMENTi OF TRANSPC]��ATICIN AUGUST 20D3 �1411Ps �OR C[DNSTIF2UCTION AN@ hAAIM��NANC� ACTIVe�V�S � N � � O � O �' � y O � 5.2 - F/ow Diversion 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 Apply �LL.y..-:: - �*=— - . , - - � -. -�::1f�...., ,'�►' 1 �;��. _z ,,t � � � � �_�. �� � � ,�'� �.' ' - � _ �" ' i?'' ' '_'y' . ,. `- � s�'� - i _ ` ..'. �.� ,. `� � , +��'!4lyp; - . ��r-� .�..--. � �,y :4,_ r4 ;Y� � E-. a � _�<. "-� " : _ ��_� , -+.�.' Figure 31 Suspended Bypass Pipe ✓ 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 W � -o m n 0 � � � 0 o' � v � a � o� �' m v � � � �D w � � < m r. a m' �� DE �l O' �N: �U� M�4,�N�4�IMC THE W�ITERCOURSE� SUS�E���� Bl�'�'AS� �'IE�E IMF�R'VIQUS pIK� � �1 SUCTIdN H4SE Td D�WATERING DEVICE M�3I�TH CAf�{}LaN� [7��AF��AIlE�� C1F T�ANS�O�iTATI�N AUGLVSt 2003 � PR�J�CT �FL01N SUM� PRC�FI�� VIEW SEALARC3U'�VD P�IPE AhJCHGJR FIPE SEC�JR�LY @�MPs FOFt C4NSTRUCTI01� AND MAINTENANC€ ACTIVITIES � rv I � O � O �' � y O � 5.2 - F/ow Diversion 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 Practice Applies Conditions Where Practice Does Not Apply 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 DZ � o � � c � � N N O � O 0 W �. v 0 � � v � � � � 0 � v � � � 0 � v o' � W � �o m 0 C) 0 � � � 0 o' � v � n � o� �' m v � � m �D v� � < m r, �m o cn �N�RGY ���.r����-�,,.� � NIr4��4� I I� ���I �'VVi��� F�+�+�L� F�S E� PIP�D [�IV�R���I� EI�SCJtl�E�'OAIUCHQRALL r�v�•�•�,�•�f � PUMPS AEJD PIPES S�CURELY. NORTH CAROLlNA DEPARTMETiT OF TRANSPORTATION A�1G�ST 2U43 BMPs F4R �ONSTRUCTION A�la MAIMTENANCE ACTIYITIES 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 Practice Applies Conditions Where Practice Does Not Apply 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 DZ � o � � c � � N N O � O 0 W �. v 0 � � v � � � � 0 � v � � � 0 � v o' � W � �o m 0 C) 0 � � � 0 o' � v � n � o� �' m v � � � �D m � � < m r. � m' w v� ENEf2GY DE MAI�A�G�iNG� THE INATER�OWIRSE: Fr�►BRIC LINE[) DIV'EE'�S��?f�Il �CH�'►N�11EL ENSURE TC)A9VCHOR ALL �•v",•r,�•��� PUMPS AN� �'IP�S S�CIJR�I�Y. f�ORTR� CAROLINA [?EPAFtTMENT O� TRANSPORTATI�W AUGI�ST 2[103 �iMPs F{}R C{}NSTRUCTION AND MAIMtT�F1ANC� ACTIYITI�S � N I � O � O �' � y O � 5.2 - F/ow Diversion 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 �. i'�I�-_•�w�?��j-�� :.e:�' ,�'"��, ;r��°�r4w�ita�`,?�R�`�i�i�'.-! F �=� � � �, � '� � . . _' . . _ 9 _' c _ ._ -. -�-c� � �. Y.�. i . _ tat'.�. +e -:. ..- .a�- � �� � ^��J-'-i �3 ��` � . . "�- ` � � ..�.Y w.e: v,_,_ � -d _��y �(++ y C- � 'Y' -J.. _ �s- =-ry� . �� - _ . { . � .. `/ � ' -. �. - - �. " -.. �.�t f• a ` �-z+.`-. .�_, " � '�-�� � :�� ��;'" ��.�__�—.``, `�`�--� r� � a-y_ . - = a:�► � �-��. r,-_ � a'-- � �.�� ]� �., -� -� --�.� "� �{^�4'-�_ � / J_;f '1S P iV :%'��,M \ _�" '� �"'��. " tt � � ti-�` � - � Q_� � � ,�,� s�<....�"�-= �-.,.,r�.�� � •+ � _ � � . �� - _�\�`�-- �:�,,;�:: ,,; _ . ��'`.. Y --� ;� _�=?='' _ _ -� � _ = � S � � . ' � . � _�.y�; � �. - . ' v ,� __r '• -- _" _ ' � .` _" �.�-•r �. ��t[Y l':=�f i '�— "M�"ti .�T� � �f1 � � ���� 'Y� � �-�' � a� �f 'Il♦� ��~� T J��}�� � ,� ti� Figure 33. Turbidity Curtain ✓ 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. � x I r. . � ± _ e� � �l _� 'R.. : ' __ ,-� ._` -��=- + . _�.� „Q`' --_ a :. � , �'`�y'';:�:, . , . ' qt���' m's.'"'i � � .� e,�,�` t � � .��-���Y� �?.� [ ��` r t �� � �5� . tib-��'*�'� _. � �� � ��4 7T � . � �. ,,, Y ; : �� r r,� , � �, . ��- � .:. �`y� � 1♦'�� � �, .k ��'<; sn� ti"k.p ��-� "' ts"' ;�` ��i� � t �, c � _ � ^ ���a"���� �,;'- � `�`,.� �. �,p ��F e'J , � ,., � . - '.• r;: �-- .. . . Z .i F�^�.. a� . - . r ♦ � � � 'n�'i�:� � � �� �,�' ��i y-�j�' R � � —��. �_� y � �it .$y� ` , J _l , �� ? �E' ,,jjilr� /,. '►�z - �r� ��Y' ' �;��+��►`,�� � «� 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 . �,�F' _ - '� a j �''" ✓,�{iF`�" {� � q .-' t � � i'. . � .$ � �' a . .�' ��F � Ld ai' ^4 � �,�it y:�� �,Y � .}.. �QL��^� i'�— P 4`� ��' ' +5-r lt' �` ^_� `� �. � s� �:IT x ��+ t . �y�, k .� � :F f�� .� �� :> �`_- �' 'r , ;� ' � �4'�.�, �. . � �`� .. } _ � ; ',, - "�r�. , ' t• --- �� ° C�i : � • ; 1y ' ti� r.-K' -` �„� � �'� .._ i :R �', ..: t.�;_ ' -� . } � `.- :r .� k ��x�'=�Fr' ' � '� �y � ��.�� = ~�'_ _ �� - _ � _ ,j�• _ r � _ _ �� -„��' r_+►��� ���` y� �' � - �� '�.- . _. _� i . e„ � - . 1{s'+ • 14' 'a � aa.�-: ` ty ` � -� . _ , r_ �,.,�.ti, i . . . � T>. � �,�''.��"y��l`�-y.�. _. _ � - �� : ,� ���' � �: �,i ir. '�, _� _ � . .. �" � ��_ ' _ " ' . • --.� _ ". ' � � ' _ ''`'�`!;. ±�'�' :,�,`'��,,. ' _ -�, - .+v -s�,. • ��v�r� � •+. �.. .�.'`-`• � �� �+`r, . +.� • � +'— 4,:5,��'S 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. r � ; 7� �, � - �l '� .�.� �� �- f�— �.5� . r _, '� # �'.ti ` , ' . ; � r� � �: 3 .; {� „ - ' , � � �'�� -- �'''� ' �'� I , _ -..�_'"�� "�. .':`.''w'.�."��l".!Y.{'Sz�'l4r ���"' ��- .:,•i� ..�i� c_ =37 �.,r�. __ J _ ;� - y :�, � - ��,t �+r.�T' - .. � � � f ,� ��•� S "•t•� . • •,� , i / -.� .� � �1,,.�' r ' �r:; � i ° �' ��y �,,'`9l,;,'. ,�.�,`�" �, . � . n� � :�� �., .. ��y'�` —_ . ;f'�s � �� ��� i�y � � . '�� r 4�.,.r ...G'y.��'.^ ^��y t1 w . ri �`� . • .'/r _ , l+i�"a ,.�-.y,v�_ �IC':.i4, . � 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 . - ---�.�_ . �:..: s - "�; .:�,��?,�;��, fi; - :-0 ' `-t" - - �.. �_ ,� . i _-. ,,.-+� - �: �. � . �- ,r"�`.� ` - . ,�:r o-y �,+• � \ �y,/,`�.�.:�s. �� i . � " _ . . -� .. *'' . . 3 . � ', �, . d ., r � Z � �� � ,1_ i ' �ti_'���- a� �t.� .. � . P' ,.1�- j.1► r Y`, ; �, ,�4 �. A � i. Y , � � �i;,,�. � �- ,�I �' `' �` _..� -� ''. %� s - ��y . 1 ' �`.� : �- i ..- . � . � � � 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. -� ��1-�'��'���1. �, `,,;.;=_.},;.`, ;� ` ,����� t �``''��� ���`,�,, �, � . � � . `t .: `i `r.,. ��S :�_. � = - ` R' '�. �; �,.4.�,;.. r�� � � '� } •� .�'� f' ,� � 51 "< + ��" f i,�� .-.a 5 �, `��_ � a t-�. a a s ` �; � }' � � �;.#_ .,<r, ,. ����- - a}: _ . _ � ,� -' L ��� i , �, � y,y� . - s.� � .1��=� 'Tt, � k.�n { . ' � iC"F .; Q, r . ..- ��. �'' _. _ ` �r :.�, :� � a j„ , �� ��. �- �a- � ,� �:. 3 -�,. - . _ i r���,_�,� - 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 � � � � ,--- ::n T� ----� � .. . :�a : • � � - ����-"j Iw� ,� .C� �•f��� +v- .� '4i,� - ` '11►� � Ma .� : - _T • > - d � i 9L- ,�jpj�� . r" i .. .� 4 �` • � . . _..•`+�1' � I-'I�a..,'tir."�- f� � � ^:" �� -. _ '1�` ,. ._ ,. w�,-" #�i, � � 1'� r =: •� t �X � � . . } '� � � _ � _� �'L � a. L � ", < i�� . ---� ,_ �` ► tl Y� �f � ����� .F.�'� fl' i�.,.n,���`'�� ,� ` -, .� � � � � � -.� � ` � J��� � - � .f' �� ..i'a��_ ! �'�! h{�� : a,� ' �',:r ��`'�' .�t �� � -� ._°� —i�C�,rc� � ,++�� � �'_ �,y� + y�.�yy�`., -• � � IM � ' � � : ` ` ��r � y ' t� �� 1 ' r �� �� � t ��� � � 1' . � .. � � � �a�� y � � �� /,' -�. ��i: � j �' � �- � �,,�f��� t � �a�� " .�. �4�����y'�- '�� r� — I �• n� J�y�_� � .ey��S���.�F �I 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 � n v v m Z O k n I Ci O Z n � y r y y 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 North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 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 August 2003 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. North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 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, North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 APPENDIX E— ENV/RONMENTAL PERM/TS & CERT/F/CAT/ONS 2003 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 August 2003 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 North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 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. North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 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. BMPs for Construction and Maintenance Activities NOTES: North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 NOTES: North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 NOTES: North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 NOTES: North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 NOTES: North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 THIS PAGE INTENTIONALLY LEFT BLANK North Carolina Department of Transportation BMPs for Construction and Maintenance Activities August 2003 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