ADOT erosion and pollution control manual for highway design and construction 
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As submitted to ADEQ on 2/1/2005. Document is subject to modification and will be updated as deemed necessary.
ADOT EROSION AND POLLUTION CONTROL MANUAL
For Highway Design and Construction
Arizona Department of Transportation
Intermodal Transportation Division
ADOT EROSION AND POLLUTION CONTROL MANUAL
Wheat Scharf Associates ADOT Erosion and Pollution Control Review Committee Joseph Salazar Roadside Development Section Zitao Fang Roadside Development Section Andrew Roth Prescott District Kirk Kiser Phoenix Construction District Colleen Kelley EcoPlan Associates Terry Brennan Tonto National Forest
for the under the direction of Written and Edited by
LeRoy Brady Roadside Development Section Matthew Walkowiak Phoenix Construction District Michael Mingo Natural Resources Rob Ingram Tonto National Forest Ted Littlefield Construction Operations
Arizona Department of Transportation, Intermodal Transportation Division Wheat Scharf Associates ADOT Roadside Development Section February 2005 Arizona Department of Transportation, Intermodal Transportation Division Roadside Development Section 205 S. 17th Avenue, MD 617E Phoenix, Arizona 85007
Produced and Published by and Photography and Graphics by
TABLE OF CONTENTS 1 INTRODUCTION
1.1 PURPOSE OF MANUAL ............................................................................................................ 3 1.2WATER QUALITY REGULATIONS AND PERMITS ............................................................ 3 1.2.1 Arizona Department of Environmental Quality's (ADEQ's) Arizona Pollution Discharge Elimination System (AZPDES) Storm Water Permit Requirements. ................... 4 1.2.2 Federal Highway Administration Erosion Control Guidelines ..................................... 5 1.2.3 Section 404 of the Clean Water Act .............................................................................. 5 1.2.4 Section 401 of the Clean Water Act .............................................................................. 6 1.2.5 Additional Federal Land Requirements ........................................................................ 7 1.2.6 State and Local Government and Agency Requirements ............................................. 8 1.3BEST MANAGEMENT PRACTICE (BMP) SELECTION AND DESIGN ........................... 9
2 PROJECT PLANNINGAND DESIGN GUIDE
2.1 OVERVIEW ................................................................................................................................ 10 2.2 PROJECT PLANNING AND DESIGN ..................................................................................... 11 2.2.1. Evaluate Increased Runoff Flows .............................................................................. 11 2.2.2 Preservation of Existing Vegetation............................................................................ 12 2.2.3 Concentrated Flow Structures .................................................................................... 13 2.2.3.1 Ditches and Dikes .................................................................................................... 13 2.2.3.2 Overside Drains ....................................................................................................... 16 2.2.3.3 Culvert and Channel Outlets ................................................................................... 16 2.2.4 Slope Protection.......................................................................................................... 17 2.2.4.1 Vegetated Surfaces ................................................................................................... 17 2.2.4.2 Hard Surfaces .......................................................................................................... 18 2.2.4.3 Erosion and Sediment Control Plans and Details .................................................... 18
3 INSTRUCTIONS FOR OBTAINING ARIZONA OR FEDERAL CONSTRUCTION GENERAL PERMIT AUTHORIZATION FOR ADOT CONSTRUCTION PROJECTS
3.1 PREPARE A STORM WATER POLLUTION PREVENTION PLAN (SWPPP) ................ 20 3.1.1 Project Document BMPs ............................................................................................ 20 3.2 CERTIFY THE SWPPP............................................................................................................. 20 3.3 SUBMIT NOTICE OF INTENT (NOI) .................................................................................... 21
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3.4 RETAIN THE NOI AND THE SWPPP AT THE JOB SITE ................................................. 23 3.5 IMPLEMENT THE SWPPP ..................................................................................................... 23 3.6 INSPECT THE BMPS REGULARLY ..................................................................................... 24 3.7 ADJUST THE SWPPP TO FIT SITE CONDITIONS ............................................................ 27 3.8 MAINTAIN AN UPDATED SWPPP ........................................................................................ 27 3.9 MAINTAIN THE BMPS ............................................................................................................ 27 3.10 EVALUATE JOB SITE TO DETERMINE FINAL STABILIZATION .............................. 28 3.11 SUBMIT NOTICE OF TERMINATION (NOT) ................................................................... 28 3.12 RETENTION OF RECORDS ................................................................................................. 29 3.13 SPECIAL CONDITIONS, REQUIREMENTS AND EXCEPTIONS ................................. 30 3.13.1 Permit Requirements on Tribal Trust Lands ............................................................. 30 3.13.2 Permit requirements for projects located within 1/4 mile of Impaired or Unique Waters. ................................................................................................................................. 31 3.13.3 Permit requirements for Batch Plants, Borrow Pits and Material Pits ..................... 31 3.13.4 Waivers for Small Construction Activities ............................................................... 31
4 STORM WATER POLLUTION PREVENTION PLANS (SWPPP)
4.1 IDENTIFY ALL OPERATORS FOR THE PROJECT .......................................................... 32 4.2 DESCRIBE THE SITE AND PREPARE A SCHEDULE OF CONSTRUCTION ACTIVITIES ................................................................................................................................................... 33 4.3. SELECT BMPS TO REDUCE POLLUTANTS ..................................................................... 33 4.4 PREPARE A PLAN FOR MAINTENANCE OF BMPS ......................................................... 34 4.5 COLLECT PERMIT-RELATED DOCUMENTS ................................................................... 34 4.6 COMPLY WITH APPLICABLE FEDERAL, STATE AND LOCAL PROGRAMS........... 34 4.7 DEVELOP A SITE SPECIFIC INSPECTION PLAN ............................................................ 34
5 TEMPORARY BEST MANAGEMENT PRACTICES
5.0 INTRODUCTION ..................................................................................................................... 35 Disturbed Soil Area Management ........................................................................................ 35 5.1 SOIL STABILIZATION BEST MANAGEMENT PRACTICES .......................................... 35 5.1.1 Scheduling .................................................................................................................. 36 5.1.2 Preserve Existing Vegetation ...................................................................................... 38 5.1.3 Minibenches/ Slope Roughening ................................................................................ 40 5.1.4 Hydraulic Mulch ......................................................................................................... 44 5.1.5 Hydroseeding .............................................................................................................. 46 5.1.6 Soil Binders ................................................................................................................ 48
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5.1.7 Straw Mulch ............................................................................................................... 54 5.1.8 Geotextiles, Plastic Covers and Erosion Control Blankets/ Mats .............................. 56 5.1.9 Compost/ Wood Mulching .......................................................................................... 64 5.2 CONCENTRATED FLOW CONVEYANCE CONTROLS .................................................. 67 5.2.1 Earth Dikes/Drainage Swales ..................................................................................... 68 5.2.2 Cut to Fill Slope Transitions ....................................................................................... 70 5.2.3 Erosion Protection at Structures ................................................................................. 72 5.2.4 Rock Outlet Protection ............................................................................................... 74 5.2.5 Slope Drains ............................................................................................................... 76 5.3 SEDIMENT CONTROL BEST MANAGEMENT PRACTICES ......................................... 79 5.3.1 Erosion Control Berm................................................................................................. 80 5.3.2 Silt Fence .................................................................................................................... 84 5.3.3 Desilting Basin/ Sediment Trap .................................................................................. 88 5.3.4 Check Dams ................................................................................................................ 92 5.3.5 Sediment Wattles ........................................................................................................ 96 5.3.6 Sediment Logs .......................................................................................................... 100 5.3.7 Street Sweeping and Vacuuming .............................................................................. 104 5.3.8 Sand Bag Barrier ....................................................................................................... 106 5.3.9 Storm Drain Inlet Protection......................................................................................110 5.3.10 Curb Inlet Protection ............................................................................................... 116 5.4 WIND EROSION CONTROL BEST MANAGEMENT PRACTICES ............................... 119 5.4.1 Wind Erosion Control ............................................................................................... 120 5.5 TRACKING CONTROL BEST MANAGEMENT PRACTICES ....................................... 123 5.5.1 Stabilized Construction Entrance/Exit ..................................................................... 124 5.5.2 Stabilized Construction Roadway ............................................................................ 126 5.6 NON-STORM WATER BEST MANAGEMENT PRACTICES .......................................... 129 5.6.1 Water Conservation Practices ................................................................................... 130 5.6.2 Dewatering Operations ............................................................................................. 132 5.6.3 Paving and Milling Operations ................................................................................. 134 5.6.4 Temporary Stream Crossing ..................................................................................... 138 5.6.5 Clear Water Diversion .............................................................................................. 142 5.6.6 Vehicle and Equipment Cleaning ............................................................................. 146
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5.6.7 Vehicle and Equipment Fueling ................................................................................ 148 5.6.8 Vehicle and Equipment Maintenance ....................................................................... 150 5.7 WASTE MANAGEMENT AND MATERIALS POLLUTION CONTROL BEST MANAGEMENT PRACTICES ............................................................................................................. 153 5.7.1 Material Delivery and Storage .................................................................................. 154 5.7.2 Material Use ............................................................................................................. 158 5.7.3 Stockpile Management ............................................................................................. 160 5.7.4 Spill Prevention and Control .................................................................................... 162 5.7.5 Solid Waste Management ......................................................................................... 164 5.7.6 Hazardous Waste Management ................................................................................. 166 5.7.7 Contaminated Soil Management .............................................................................. 170 5.7.8 Concrete Waste Management ................................................................................... 174 5.7.9 Liquid Waste Management ....................................................................................... 178
APPENDIX A PERMITTING FORMS AND CHECKLISTS ................................................. A-1
A.1 A.2 A.3 A.4 A.5 A.6 A.7 SWPPP Checklist ............................................................................................................ 1 Notice of Intent (NOI) Form ........................................................................................... 1 ADOT Standard Sheet (non-tribal lands) ........................................................................ 1 ADOT Standard Sheet (tribal lands) ............................................................................... 1 ADOT AZPDES Inspection Checklist ............................................................................ 1 Methods for Determining Final Stabilization ................................................................. 1 Notice of Termination (NOT) Form ............................................................................... 1
APPENDIX B .................................................................................................... B-1 ABBREVIATIONS, ACRONYMS AND DEFINITION OF TERMS ..................... .............................................................................................................. B-1 TO B-6 APPENDIX C ................................................................................................... C-1 REFERENCES AND RESOURCES.................................................... C-1 TO C-3
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1
INTRODUCTION
Highway construction has been identified as a primary source of soil erosion and sediment loss. Construction of highways typically disturbs large areas of natural vegetative cover that can result in an accelerated rate of soil erosion. In contrast to highways of the past where the roadways were narrow and profiles followed the contour of the land, contemporary highways have wider cross sections and flatter profiles, which results in large areas of land disturbance, high fills and deep cuts (Figures 1.1 and 1.2). Consequently, highway design and construction requires careful consideration for erosion and sediment control. Erosion and sedimentation from construction sites can have environmental and economic impacts. Environmentally, some of the more common impacts of excessive erosion include: Turbidity, which reduces in-stream photosynthesis and increased water temperatures, leading to reduced food supply and aquatic habitat; Introduction of soil nutrients into waters that cause algal blooms, which reduces water clarity and depletes oxygen; Sedimentation of stream bottoms that blankets fauna and destroys spawning areas; and Removal of top soil that leaves hard, rocky and infertile soil, which is difficult to revegetate.
Figure 1.1 Today's highways have wide cross sections that result in large areas of land disturbance
These environmental impacts result in damage to aquatic habitat that is difficult to quantify in terms of costs. However, the economic impacts go beyond the cost of damage to natural resources. For example: excessive accumulation of sediment in streams and reservoirs can require dredging at very high costs; replacement and repair of eroded soil can be very expensive; and sediment removal from roadways, channels and culverts can produce additional maintenance costs and cause flood damage (Figure 1.3).
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Excessive sedimentation can also disturb the physical stability of ephemeral channels, resulting in accelerated rates of erosion and sediment deposition within the channels. Increased erosion and deposition can result in damage to native vegetation and subsequently to local wildlife populations for which ephemeral stream channels are important habitats and movement corridors. Increased channel erosion and sedimentation can also lead to accelerated delivery of sediment downstream to intermittent and perennial stream channels, thereby damaging those environments as well. The Arizona Department of Transportation (ADOT) has adopted this manual to assist in developing erosion and pollution control during both design and construction of roadways.
Figure 1.2 (Above) Rill erosion on cut slope Figure 1.3 (Below) Sedimentation at storm drain
There are three main goals: Reduce erosion potential. Reduce off-site sedimentation. Prevent contamination by construction materials. These goals are achieved by means of both permanent and temporary storm water Best Management Practices (BMPs).
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Figure 1.4 When properly designed, today's highways carefully fit into the physical and visual landscape
1.1 PURPOSE OF MANUAL The overall purpose of this manual is three-fold: To outline ADOT's procedures for complying with water quality regulations and permits. To provide a "tool box" of available BMP's. To provide guidance for the selection of BMPs on ADOT construction projects. 1.2 WATER QUALITY REGULATIONS AND PERMITS
All ADOT construction projects must comply with federal, state and local water quality regulation and permit requirements. Attention must be given to these regulations and permit requirements through-out the planning, design and construction of a project to insure that the quality of the waters of the U.S. is not compromised. The following is a general overview of the pertinent regulations and permitting requirements.
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1.2.1 Arizona Department of Environmental Quality's (ADEQ's) Arizona Pollution Discharge Elimination System (AZPDES) Storm Water Permit Requirements. On Dec. 5, 2002, Arizona became one of 45 states with authorization from Environmental Protection Agency (EPA) to operate the National Pollutant Discharge Elimination System (NPDES) Permit Program (Section 402 of the Clean Water Act) (CWA) at the state level. Under the AZPDES Permit Program, all facilities that discharge pollutants from any point source into waters of the U.S. are required to seek coverage under an AZPDES permit. Pollutants can enter waters of the U.S. from various sources including agricultural, domestic, and industrial. For regulatory purposes, these sources are generally categorized as either point source or non-point sources. For similar types of construction activities, the ADEQ has issued a Construction General Permit (CGP), Arizona Construction General Permit (AZCGP) No. AZG2003-001, which is available to provide storm water permit coverage to all construction projects in the State of Arizona (except on Tribal Trust Lands where the construction general permit is issued by the EPA, termed the Federal Construction General Permit or FCGP in this document). In order to comply with the conditions of either the AZCGP or the FCGP, the operator is required to file a Notice of Intent (NOI) with ADEQ or EPA if construction and construction-related activities, including all clearing, grading, excavation, and stockpiling activities, will result in the disturbance of equal to or greater than one acre. ADEQ or EPA approves the specific project use of the general permit for storm water discharges by accepting and approving the NOI. If ADEQ or EPA denies NOI approval, the operator may have to pursue an individual storm water discharge permit for the project. The AZCGP specifies allowable storm water discharges (Part I.C) from construction sites and requires the operator to meet water quality standards through implementation of temporary and permanent BMPs and other measures. Compliance with the requirements of the AZCGP constitutes compliance with the National Pollution Discharge Elimination System permit. In order to obtain coverage, construction contractors under contract to ADOT and ADOT representatives shall:
Comply with all terms and conditions of the AZCGP or FCGP. Prepare and implement a site specific Storm Water Pollution Prevention Plan (SWPPP) which meets the minimum requirements of Part IV of the AZCGP. Submit an NOI to ADEQ after the contract has been awarded and before any construction activity begins (the NOI is submitted to the EPA if the project is located on Tribal Trust Lands). These requirements are described under Part II.B and Part III of the AZCGP.
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Submit a Notice of Termination (NOT) to ADEQ when construction is complete, all permanent erosion and sedimentation controls are in place, and final stabilization has been achieved to meet the requirements described in Part II.C of the AZCGP. The NOI is submitted to the EPA if the project is located on Tribal Trust Lands.
Chapters 3 and 4 of this manual provide instructions for preparing a SWPPP and completing the NOI and NOT forms for ADOT projects. 1.2.2 Federal Highway Administration Erosion Control Guidelines Section 1057 of the Intermodel Transportation Efficiency Act of 1991 (ISTEA) requires the Federal Highway Administration (FHWA) to develop erosion and sediment control guidelines for States to follow when building highways using Federal funds. FHWA has formally adopted the American Association of State Highway and Transportation Officials (AASHTO) Highway Drainage Guidelines, Volume III (see Reference 1, Appendix c), for this purpose. Each State highway agency is required to comply with the AASHTO Guidelines or to develop and apply their own more stringent guidelines. 1.2.3 Section 404 of the Clean Water Act Section 404 of the CWA regulates the discharge of dredged or fill material within the waters of the U.S. and establishes a program to issue permits. In Arizona, the U.S. Army Corps of Engineers (Corps) administers this program. In addition, the U.S. Fish & Wildlife, the National Marine Fisheries Service and State resources agencies (e.g., ADEQ, Game and Fish Department, Water Resources) have important advisory roles. The phrase "discharge of dredged or fill material" includes all earthwork activities such as clearing, grading, filling, and excavating. The 404 program has considerable impact on the design, construction and maintenance of Arizona's highways. Essentially, any proposed work in washes, rivers, streams, lakes and wetlands requires ADOT's Environmental and Enhancement Group (EEG) to obtain a permit from the Corps. During construction, the Corps evaluates adherence to permit conditions. Typical projects that are affected include the construction and maintenance of culverts, bridges, and stream bank erosion protection. There are two types of 404 permits: nationwide permits and individual permits. Nationwide permits are general permits designed for allowing minor, noncontroversial projects that are similar in nature, and which create minimal impact on the environment. Individual permits are required for projects that do not meet the terms and conditions for a nationwide permit. They require greater scrutiny by the Corps, other regulatory agencies and the public.
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1. Introduction
Requirements for nationwide permits in Arizona are found in the Corps Special Public Notice dated April 19, 2002. Some projects may require an individual permit. The Corps should be contacted for determination of permit requirements. U.S. Army Corps of Engineers Regulatory Branch 3636 N. Central Avenue, Suite 900 Phoenix, AZ 85012-1939 (602) 640-5385 FAX (602) 640-2020 The federal Section 404 permit program can be easily confused with the ADEQ, Section 402, AZPDES program. It is important to remember, however, that they are two separate and distinct regulatory programs. The distinction is that a Section 404 permit provides permission to add fill material to the waters of the U.S., whereas an AZPDES permit provides permission to discharge treated storm waters to the waters of the U.S. in compliance with permit limitations, conditions and BMPs. 1.2.4 Section 401 of the Clean Water Act Section 401 of the CWA enables the States to provide certification that the draft 404 permit is in compliance with State law. ADOT Environmental Planning Group obtains 401 Certification during the design process. The purpose of Section 401 is to ensure that the proposed activity meets the State's water quality standards and any other pertinent state-required criteria. In Arizona, ADEQ performs the State Water Quality Certification Review for all areas of the State with the exception of Indian Reservations. For projects within the White Mountain Apache Reservation, the Tribal Environmental Planning Office performs certification reviews. For projects within all other Indian Reservations in Arizona, EPA performs certification reviews. Section 401 certification requirements apply to all activities regulated under Section 404 of the CWA. The certification review evaluates proposed projects for compliance with state water quality standards and consistency with approved water quality planning and management programs. ADEQ may approve or deny certification for any Section 404 Permit based on the anticipated effect on water quality. A Letter of Certification will be issued by ADEQ if the applicant is in compliance with these standards and conditions. In order to obtain a letter of certification from ADEQ, construction contractors under contract to ADOT and ADOT representatives shall contact ADEQ Water Permits Division.
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1.2.5 Additional Federal Land Requirements There are several agencies within the U.S. government that manage public lands and may have their own erosion and pollution control requirements. These agencies include the BLM, the BIA, the U.S. Forest Service, the National Parks Service and the U.S. Fish and Wildlife Service. Each affected agency shall be included in the planning and design process when roadway plans are prepared within their jurisdictions. Doing so will ensure that their requirements are incorporated into the plans. Contact Information: Bureau of Land Management � http://www.blm.gov/nhp/ Bureau of Indian Affairs - www.doi.gov/bureau-indian-affairs.html The U.S. Department of Agriculture Forest Service � www.fs.fed.us/ Southwestern Region USDA Forest Service 333Broadway SE Albuquerque, NM 87102 (505) 842-3192 The National Parks Service � www.nps.gov/ Pacific West Region, Regional Director National Park Service One Jackson Center 1111 Jackson Street Suite 700 Oakland, CA 94607 (510) 817-1300 U.S. Fish and Wildlife Service � www.fws.gov/ Southwest Region 2 500 Gold Ave. SW Albuquerque, NM 87102 (505) 248-6635
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1.2.6 State and Local Government and Agency Requirements The Arizona State Land Department does not have a specific policy on erosion control for construction projects but rather reviews projects on a case-by-case basis. For projects that are located on State Trust Land contact: Arizona State Land Department Right-of-Way Section 1616 W. Adams St. Phoenix, AZ 85007 (602) 542-4098 Other environmental issues such as archaeological and/or historic sites may be identified during project planning and design that affect design and construction activities. These issues may affect the contractor's proposed activities outside of the approved right-of-way. Projects may also be located within the jurisdictions of local governments. These may include Municipal Separate Storm Sewer Systems (MS4) and County Flood Control Districts. Each affected agency shall be included in the planning and design process when roadway plans are prepared within their jurisdictions. This will ensure that their requirements are incorporated into the plans. Contact Information: Local Government Units Phone Listings in Government Pages Arizona Council of Governments Website http://www.mag.maricopa.gov/archive/AZ-COGs/index.html Municipal Separate Storm Sewer Systems Arizona Department of Environmental Quality Listings http://www.adeq.state.az.us/environ/water/permits/stormwater.html EPA Region 9: Water Programs Website http://www.epa.gov/region09/water/npdes/stormwater.html County Flood Control Districts Phone Listings County Government Pages Arizona Association of Counties Website http://www.azcounties.org/home/index.cfm
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1.3
BEST MANAGEMENT PRACTICE (BMP) SELECTION AND DESIGN
As used in this document, the term BMP refers to operational (non-structural) activities or physical controls (structural) that prevent or reduce the discharge of pollutants and minimize potential impacts upon receiving waters. Proper BMP design, selection and installation are essential to achieve the goals of this manual. BMP selection begins during the design phase but must be continued by the contractor and ADOT throughout the life of the project. The most effective way to reduce erosion and offsite sedimentation and to prevent the contamination of storm water is to select and install BMPs that best fit the specific conditions encountered. This manual provides the following: Chapter 2: Design guidance for incorporating storm water quality controls in projects during the planning and design phases. Chapter 3: Instructions to the contractor for obtaining a Construction General Permit. Chapter 4: Instructions to the contractor for preparing a SWPPP, a necessary requirement of the General Permit. Chapter 5: Descriptions of both temporary and permanent BMPs for consideration by ADOT and the contractor during design and construction of ADOT projects.
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2
PROJECT PLANNING AND DESIGN GUIDE
2.1 OVERVIEW As used in this document, the term BMP refers to operational activities or physical controls that reduce the discharge of pollutants and minimize potential impacts upon receiving waters. There are two categories of BMPs within ADOT: Permanent Pollution Prevention BMPs and Temporary Pollution Prevention BMPs. Permanent Pollution Prevention BMPs are permanent measures to improve storm water quality both during and after construction of the project. They include: 1. The minimization of impermeable surfaces; 2. The re-establishment of vegetation to disturbed soils (Figure 2.1); 3. The evaluation of increased runoff flows; 4. The preservation of existing vegetation; 5. The design of concentrated flow structures; and 6. The design of measures to protect disturbed slopes.
Figure 2.1 Revegetated cut slope
Figure 2.2 Installation of erosion control blanket
Temporary Pollution Prevention BMPs are temporary measures to improve storm water quality during the construction process. They include: 1. Temporary soil stabilization and sediment control (Figure 2.2); 2. Non-storm water management; and 3. Waste management. The objective of this chapter is to provide guidelines for the consideration of permanent pollution prevention BMPs during the ADOT planning and design processes.
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2.2 PROJECT PLANNING AND DESIGN During the design process, the Landscape Architect and Engineer must endeavor to minimize the impacts to water quality that may be caused by the project. In order to maintain water quality affected by a project, ADOT has established the following objectives: 1. Maximize vegetated surfaces; 2. Stabilize disturbed soils; 3. Prevent downstream erosion. The designer should consider the BMPs described in this chapter in order to achieve these objectives. 2.2.1. Evaluate Increased Runoff Flows The project design may increase the amount of impermeable surface area within the project area, resulting in increased runoff quantities from the project site. The project design may also increase the velocities of existing offsite runoff flows by concentrating those flows into smaller drainage structures. Consequently, large storm events may result in greater peak runoff discharges into existing drainages than those drainages may have historically received. To address these concerns, the designer shall consider the following: Drainage design: Bridges typically affect offsite runoff less significantly than do culverts and may be less visually intrusive; Bio-engineered designs such as live fascines and/ or pole plantings; Modifications to receiving drainages: the drainage may need to be protected by means of vegetation, geotextile mats, rock or riprap; Energy dissipation devices at culvert outlets; Reducing the turbulence and scour at culvert inlets and outlets by smoothing the transition between culvert inlets and outlets and drainages; Incorporating detention facilities into project design in order to reduce peak discharges; and Spread runoff flows across channel outlet structures in order to mimic natural drainage channels.
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Figure 2.3 Preserving vegetation and limiting land disturbance are major factors in highway erosion prevention
2.2.2 Preservation of Existing Vegetation Existing vegetation provides natural protection against soil erosion and should be preserved wherever possible (Figure 2.3). Mature plants have extensive root structures that help hold soil in place and reduce erosion. Vegetative foliage also helps reduce erosion by absorbing the impact of raindrops that would otherwise fall directly to the ground and erode the soil. Disturbed soils typically erode at much greater rates than do undisturbed soils. T h e r e f o r e , the designer should seek to minimize land disturbance by the following general guidelines: Minimize land disturbance through appropriate design to balance cut and fill and to reduce the length and steepness of the highway slopes and the extent of grading (typically, vegetation will not successfully colonize slopes greater than 2:1, H: V); Areas to be preserved should be delineated prior to the start of soil-disturbing activities. Vegetation that lies within transition areas of cuts or fills and outside of clear zones should be preserved in place; For larger projects, existing vegetation should be preserved for as long as possible where activity will occur later in the construction process; Temporary roads should be located to avoid stands of significant vegetation and to follow existing contours to reduce cutting and filling; and Temporary roads should be located within limits of area to be disturbed by permanent road construction. 2-12
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Figure 2.4 and Figure 2.5 Swale with check dams
2.2.3 Concentrated Flow Structures 2.2.3.1 Ditches and Dikes These are permanent devices used to intercept and direct surface runoff into a drain and/or into an existing drainage. Because they concentrate storm water runoff, they are highly susceptible to erosion. Therefore, the designer should consider the following: The drainage design should include calculations of peak flows and velocities for all drainage structures and should provide erosion control measures where erodable velocities occur (Table 2.1); To prevent downcutting, riprap should be considered for all ditches and dikes that exceed five percent slope; and Rock check dams reduce runoff velocity and capture sediment (Figures 2.4 and Figure 2.5).
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Figure 2.6 Cut fill transition
Maximum Permis s ibl e Velocities For: S oil Type or Lining (earth: no vegetation) W ter a W ter C arrying a C lear W ter C arrying Fine a S and and S ilts Gravel F.P.S. Fine sand (noncolloidal) Sandy loam (noncolloidal) Silt loam (noncolloidal) Ordinary firm loam Fine gravel Stiff clay (very Colloidal) Graded, loam to cobbles (noncolloidal) Graded, silt to cobbles (colloidal) Alluvial silts (noncolloidal) Alluvial silts (colloidal) Coarse gravel (noncolloidal) Cobbles and shingles Shales and hard pans 1.5 1.7 2.0 2.5 2.5 3.7 3.7 4.0 2.0 3.7 4.0 5.0 6.0 F.P.S. 2.5 2.5 3.0 3.5 5.0 5.0 5.0 5.5 3.5 5.0 6.0 5.5 6.0 F.P.S. 1.5 2.0 2.0 2.2 3.7 3.0 5.0 5.0 2.0 3.0 6.5 6.5 5.0
Table 2.1. Permissible Velocities for Channels with Erodible Linings, Based on Uniform Flow in Continuously Wet, Aged Channels1 As recommended by Special Committee on Irrigation research, American Society of Civil Engineers, 1926. From: FHWA - Hydraulic velocity by: 0.95 for slightly sinuous; 0.90 for moderately sinuous; and 0.80 for highly sinuous.
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Figure 2.7 (left) Spillway (with failed temporary embankment curb) Figure 2.8 (right) Culvert protection
Ditches and dikes also act as devices to prevent erosion. During the design process, the designer should consider the following: Crown ditches installed at the tops of slopes to divert runoff from adjacent cut slopes. Construction should take place prior to excavation of the slope. The designer should give careful consideration to crown ditch outlets to avoid downstream erosion and minimize ditch maintenance. In addition, since crown ditches can be highly visible to motorists, consideration should be given to ditch layout and existing vegetation. Finally, the designer should keep in mind that all ditches required maintenance; therefore, crown ditch access should be a consideration; Slope ditches: Installed at bottom and mid-slope locations to intercept sheet flow and convey concentrated flows; Embankment curbs: Installed on fill slopes at the edge of the roadway to intercept sheet flow from paved surfaces. Embankment curbs are of special consideration where the roadway is super-elevated, thereby directing all sheet flow to one side of the pavement; and
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Cut-to-fill slope transition protection: Installed at the intersection of cut and fill slopes. Cut ditches that discharge at cut-to-fill slope transitions will normally require erosion protection until runoff flows reach an existing stable drainage (Figure 2.6).
Figure 2.9 Rock rip rap at culvert
2.2.3.2 Overside Drains Overside drains are pipes, downdrains and spillways used to protect slopes against erosion by collecting surface runoff and conveying it down the slope to a stabilized drainage. The designer should consider their use as follows: Cut slope spillway: Installed where offsite runoff will intercept a cut slope. Because cut slopes typically are highly visible to motorists, consideration should be given to the aesthetic design of these structures; and Fill slopes: Where embankment curbs are installed, openings in the curb are constructed that drain into a spillway or downdrain. Generally, downdrains are used for aesthetic reasons where slopes will be visible from a main roadway (Figure 2.7). 2.2.3.3 Culvert and Channel Outlets Culvert and structural channel outlets are typically areas of high concern for erosion. The designer should consider the following: Careful review of inlet invert elevation: When lower than the existing natural channel, the channel backslope must be protected to avoid headcutting of that slope by runoff;
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2. Project Planning and Design Guide
Flared end section: These are typically installed at the inlets and outlets of pipes and channels to improve the hydraulic operation, retain the embankment near pipe conveyances and help prevent scour (Figure 2.8); Outlet protection/ velocity dissipation devices: In order to prevent scour at the outlet and to reduce runoff flow velocity, rock riprap or some other measure is typically installed. These devices should be constructed during or immediately after construction of the culvert; and Protection at the soil/ drainage structure interface: The interface between fill slope soils and concrete or metal structures is typically prone to erosion. While this interface frequently occurs at drainage structure outlets, it is also possible at the edges of spillways and bridge abutments. The designer should consider the use of rock or other protective measure to prevent erosion in this area (Figure 2.9).
2.2.4 Slope Protection Surface protection consists of permanent design measures that are used alone or in combination to minimize erosion from disturbed surfaces. Vegetated surfaces may offer several advantages to paved surfaces including lower runoff volumes, slower runoff velocities, increased times of concentration and lower cost. However, where site-specific conditions would prevent adequate establishment and maintenance of a vegetative cover, hard surfacing should be considered. 2.2.4.1 Vegetated Surfaces A vegetated surface is a permanent vegetative cover on areas that have been disturbed. The purpose of the vegetated surface is to prevent erosion and remove pollutants (including sediment) in storm water runoff. Vegetated surfaces should be established on areas of disturbed soil after construction related activities in that area are completed and after the slope has been prepared. Vegetated surfaces should only be considered for areas that can support the selected vegetation long-term. Typically, responsibility for treatment of vegetated slopes rests with the project Landscape Architect as follows: Project site shall be evaluated for soil types and conditions; topography; local climate and season; existing native vegetation types and species; Surfaces to be vegetated shall be designed to maximize rainfall infiltration and minimize concentrated flow volumes and speeds. Slopes shall be considered for roughening, terracing, and rounding; and Existing project site topsoil and vegetation shall be considered for salvage during clearing and grubbing operations. Use salvaged materials as part of surface preparation prior to seeding.
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2.2.4.2 Hard Surfaces Hard surfaces consist of placing concrete, rock or rock and mortar. Typically, these measures are considered where vegetation will not provide adequate erosion control and/or where vegetation will be difficult to maintain. The designer should to consider the downstream effects of increased runoff volumes and velocities from hard surfaces. Typical applications include bank protection and bridge abutments. 2.2.4.3 Erosion and Sediment Control Plans and Details. As part of the project design process, the designer should develop plans and details which direct the contractor to the proper locations, installation and maintenance of BMPs. The intent of these plans is to provide general direction and specific BMP expectations to the contractor. They will not be considered a complete SWPPP and shall not replace the contractor's SWPPP, since the project plans and details are prepared assuming standard construction practices and may not reflect the contractor's actual methods of construction, access requirements or project phasing. The contractor shall use the project plans as a guide in developing his own SWPPP.
Figure 2.10 Installation of sediment wattles
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3
INSTRUCTIONS FOR OBTAINING ARIZONA OR FEDERAL CONSTRUCTION GENERAL PERMIT AUTHORIZATION FOR ADOT CONSTRUCTION PROJECTS
The following sections describe the steps that ADOT and the general contractor will follow to comply with the ADEQ's AZCGP requirements (federal CGP instructions are described at the end of this chapter). Within each section a short summary of responsibilities for the individuals involved in the construction process is explained. It is ADOT's intent to share responsibilities on the job site with the contractor. It shall not be the general contractor's nor ADOT's sole responsibility to comply with AZCGP requirements. Instead, it is a shared obligation between ADOT and the general contractor and subcontractors to protect the environment.
S tep Step 1 Action Prepare a Storm Water Pollution Prevention Plan (SWPPP). Certify the SWPPP AZC GP R eference Part IV Information & forms Chapter 4 Appendix A, Contract Documents ADOT Stored Specification 104SWDEQ ADOT Standard Sheet-Appendix A "AZPDES SWPPP Index" Appendix A www.adeq.state.az.us Project Specifications Project Specifications
Step 2
Part IV.C.1, Part IV.J.1, Part VII.K Part III
Step 3
Submit a Notice of Intent (NOI)
Step 4
Retain the NOI and SWPPP at the job site Implement the SWPPP
Part IV.J.
Part IV.D
Step 5 Inspect the BMP's regularly and after Part IV.H, each storm event Adjust the SWPPP to fit site conditions Maintain an Updated SWPPP Maintain the BMPs Part IV.H.7 Part IV.I Part IV.E.1 -3
Maintenance, record keeping and sitemonitoring forms - Appendix A Project Specifications ADOT Inspection Form Appendix A Project Specifications Project Specifications Project Specifications BMP descriptions-Appendices A & B Final Stabilization Methods Appendix A Project Specifications Appendix A www.adeq.state.az.us Project Specifications Project Specifications
Step 6 Step 7 Step 8 Step 9 Step 10
Evaluate job site to determine if Final Part IX - definition of Stabilization is achieved final stabilization Submit Notice of Termination (NOT) Part II.C
Step 11 Step 12 Retain Records after project is complete for 3 years. Part VI
Table 3.1 Steps for obtaining Arizona Construction General Permit Authorization
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.1 STEP 1: PREPARE A STORM WATER POLLUTION PREVENTION PLAN (SWPPP) A complete SWPPP shall be developed by an Erosion Control Coordinator who is designated by the contractor in accordance with the project specifications. Instructions for completing a SWPPP are included in Chapter 4. Two copies of the draft SWPPP shall be submitted to the Engineer at the preconstruction conference if possible, but not later than 14 calendar days from the Department's approval of the contractor's Erosion Control Coordinator. Responsibilities: ADOT: Provide supporting documents required to complete the SWPPP. Review the credentials of the Erosion Control Coordinator selected by the contractor. Review the draft SWPPP submitted by the contractor. The Contractor: Designate an Erosion Control Coordinator. The Erosion Control Coordinator shall prepare the SWPPP. 3.1.1 Project Document BMPs As described in Section 2.2.4.3, during the project design process ADOT will prepare storm water pollution prevention plans (entitled "Erosion and Sediment Control Plans"), details (entitled "Erosion and Sediment Control Details") and specifications (in Section 810 of the Special Provisions) using BMPs from this manual and BMPs developed for unique conditions particular to individual projects. The project documents will provide direction and specific expectations to the contractor regarding storm water pollution prevention. However, these documents shall not be considered a complete SWPPP and shall not replace the contractor's SWPPP, since the project documents are prepared assuming standard construction practices and may not reflect the contractor's actual methods of construction, access requirements or project phasing. Instead, the contractor shall use the project documents as a guide in developing his own SWPPP. 3.2 STEP 2: CERTIFY THE SWPPP ADOT, the contractor and any subcontractors that are responsible for constructing the pollution controls must certify the SWPPP. In the case of ADOT local government projects involving federal aide, the appropriate municipality shall also certify the SWPPP. Refer to the AZCGP Part IV.C.1, Part IV.J.1, and Part VII.K for specific instructions. The certifications shall occur after award of the contract and before construction begins.
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects
As described earlier, it is the obligation of all personnel involved in the construction process to protect the environment. The certification requirement shall reinforce the fact that it takes a team effort to properly control storm water pollution and that the responsibility is equally shared between ADOT and its contractors and subcontractors. The following certification is required by ADEQ and is included on ADOT's "AZPDES SWPPP Index" Sheet (Appendix A). Responsibilities: ADOT: The Engineer will certify the SWPPP. I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. The Contractor: The Contractor, the Erosion Control Coordinator and any Subcontractors who are involved in implementing measures identified in the SWPPP must sign the certification. 3.3 STEP 3: SUBMIT NOTICE OF INTENT (NOI) A complete and accurate NOI form must be prepared and signed by the operator(s) to receive coverage under the AZCGP. The NOI form serves as a promise that the operator(s) will comply with the AZCGP conditions. An operator(s) is any person associated with the project that has control over the construction plans or specifications (the ADOT Engineer) or day-to-day operational control of the site (the Contractor, the Erosion Control Coordinator, and any Subcontractor directly associated with installation or maintenance of BMPs). Refer to Part IX of the AZCGP for a complete definition of operator. The NOI must be mailed to ADEQ at least 2 business days before any construction activities occur at the site (AZCGP Part III.C.1). If the project is located within or has the potential to discharge to an MS4, a copy of the NOI must also be submitted to the MS4 (AZCGP Part III.F). A list of MS4 municipalities in Arizona is located on the ADEQ website (www.adeq.state.az.us). Also, contractors operating under an approved local sediment and erosion control plan, grading plan, or storm water management plan shall submit a signed copy of the NOI to the local authority upon their request. If the project site is
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects
located within 1/4 mile of unique or impaired waters, the NOI must be submitted at least 32 business days before any construction activities occur at the site (AZCGP Part II.B.1). A SWPPP that satisfies the conditions of the AZCGP must be completed and certified prior to submitting the NOI to ADEQ. It is not necessary for the SWPPP to be included with the NOI, but the SWPPP must always be available for ADEQ review. The SWPPP must be submitted to ADEQ with the NOI if the construction site is located within 1/4 mile of a unique or impaired water (AZCGP Part II.B.1). The NOI form and detailed instructions for completing the form are available at the ADEQ website (www.adeq.state.az.us) or by calling either 602-771-4665 or 602-771-4449. Submit NOI form by certified mail or hand delivery to: Arizona Department of Environmental Quality Water Permits Section/Storm Water NOI (5415B-3) 1110 W. Washington Street Phoenix, AZ 85007 Forms can be faxed to 602-771-4674. The agency now offers a Web-based service to assist individuals in applying for construction storm water discharge permits (Smart NOI). Access the website as described above. Responsibilities: ADOT: Because of its control over the project specifications, ADOT is required to submit the NOI. Following approval by ADOT and completion of the Contractor-prepared SWPPP, the Engineer shall prepare, sign, and mail the NOI for ADOT. The Contractor: Because he has day-to-day control over the job site, the Contractor also is required to submit the NOI. The Contractor shall prepare the NOI after certification of the SWPPP and mail the signed forms at least 48 hours before any construction begins.
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.4 STEP 4: RETAIN DOCUMENTS AT THE JOB SITE The following documents must be kept with the SWPPP and retained on the job site, or a location easily accessible during normal business hours, throughout the construction process:
Document Copy of the AZPDES AZCGP (AZG2003-001) NOI (as completed by the contractor and ADOT) AZPDES authorization number for the project. Other agreements with any state, local or federal agencies that affect the provisions or implementation of the SWPPP.
AZC GP R eference
S ource www.adeq.state.az.us
Part IV.J Part IV.J.2 Part IV.J.3
www.adeq.state.az.us Provided by ADEQ after NOI is approved. ADOT environmental clearance documents
Responsibilities: ADOT: The Engineer shall keep copies of the above-mentioned documents at the construction office. The Contractor: The contractor shall post a sign or other notice near the main entrance of the construction site with specific information requested in Part IV.J.2 of the AZCGP. If the contractor maintains a construction office at or near the site, the SWPPP with all the above-mentioned attachments shall be kept at the office. If there is no construction office, the contractor's superintendent and ADOT's inspector shall keep copies in their vehicles. 3.5 STEP 5: IMPLEMENT THE SWPPP After the NOI is accepted and an authorization number received, construction may begin that will require implementation of the SWPPP (Quick Start projects require special coordination with the Engineer). The pollution controls (i.e., the BMPs) shall be constructed in accordance with the SWPPP. The SWPPP is intended to be a dynamic plan that shall be revised as a result of unanticipated or changing conditions during construction. Making changes to the plan where it is not effective is a requirement of the AZCGP. Any changes to the plan shall be noted and dated on the plan.
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects
Responsibilities: In order to effectively implement the SWPPP, ADOT and the contractor shall monitor and record weeklyextended weather forecasts. The contractor and the Engineer shall discuss these forecasts at regularly scheduled weekly progress meetings. In the event that extended forecasts report a high probability for precipitation in the project area, the contractor shall ensure that all BMPs in the SWPPP have been properly installed and maintained. He shall also install additional measures in areas determined to be susceptible to erosion as directed by the Engineer. Stabilization measures shall be installed within 14 calendar days in portions of the site where construction activities have temporarily or permanently ceased. Exceptions can be found in the AZCGP Part IV.D.4. The Engineer and the contractor are jointly responsible for implementing the SWPPP and maintaining dated records of : Major grading activities. Areas where construction activities have temporarily or permanently stopped. Installation of stabilization measures (BMPs). Delays and reasons for delays of installation of stabilization measures. These records shall be included in the SWPPP. A sample form for record keeping is included in Appendix A. 3.6 STEP 6: INSPECT THE BMPS REGULARLY Regular site inspections are required as part of the AZCGP (Part IV.H) to ensure that BMPs are functional and that the SWPPP is properly maintained. The AZCGP requires regular inspections. In areas of the state that receive greater than 20 inches mean annual rainfall, the inspection requirement is every 7 calendar days or once every 14 calendar days and within 24 hours after a rainfall event of 1/2 inch or greater. In areas of the state that receive less than 20 inches mean annual rainfall and construction occurs during the seasonal dry period, inspections are required monthly, anytime rain is predicted and within 24 hours following a rainfall event of 1/2 inch or greater. Refer to the following map (Figure 3.1) to determine the locations in Arizona where the mean annual rainfall is less than or greater than 20 inches. The reduced inspection frequency requirement also applies to sites where runoff is unlikely due to winter conditions.
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects
Inspections must be preformed by qualified personnel as described in Part IV.H.3 of the AZCGP and as specified in the project specifications. Inspections must include all areas of the site disturbed by construction activity, staging areas and areas used for storage of materials that are exposed to precipitation. Refer to AZCGP Part IV.H.4 for a complete scope of inspections. ADOT has developed an AZPDES inspection checklist to be used on ADOT construction projects (Appendix A). The completed ADOT checklist and any additional sheets necessary to record the results of the inspection shall serve as the Compliance Evaluation Report (Part IV.H.5). The Report and the record of any follow-up actions taken shall be retained as part of the SWPPP. Responsibilities: ADOT: Responsible for inspections of BMPs and approval of any follow-up actions deemed necessary following the inspections. The Contractor: Responsible for inspections, inspection reports and installation and maintenance of all BMPs. Responsible for required follow-up actions within time limits described in project specifications.
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects
Figure 3.2 Arizona Climate Map
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.7 STEP 7: ADJUST THE SWPPP TO FIT SITE CONDITIONS The operator shall implement follow-up actions based on results of the inspection process within seven calendar days following the inspection, or as required by the project specifications. Where adjustments to the SWPPP are deemed necessary, implementation must be completed before the next anticipated storm event or as soon as practical (AZCGP Part IV.H.7). Responsibilities: ADOT: Responsible for the approval of any changes or additions to the SWPPP based on specific site conditions. The Contractor: Responsible for the installation and adjustment of BMPs to fit specific site conditions deemed necessary as a result of inspections. The contractor is also responsible for recording these actions on the SWPPP. 3.8 STEP 8: MAINTAIN AN UPDATED SWPPP It is imperative that the SWPPP remain current with the changes and adjustments made in the field. Failure to update the SWPPP is considered a violation of AZCGP conditions and grounds for issuance of a failure notice. The SWPPP shall be updated within 15 calendar days if changes in design, scheduling or maintenance activities have a significant effect on the discharge of pollutants or it is determined that discharges from the construction site are causing or contributing to water quality exceedances (Refer to AZCGP Part IV.I). Responsibilities: ADOT: The Engineer must retain copies of updated SWPPP in his vehicle. The Contractor: Must maintain an updated SWPPP. 3.9 STEP 9: MAINTAIN THE BMPS All erosion and sediment control measures and other protective measures identified in the SWPPP must be maintained in effective operational condition (Refer to AZCGP Part IV.E.1-3).
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects
Responsibilities: ADOT: Responsible for inspections and approval of maintenance activities. The Contractor: Responsible for the maintenance of all erosion and sediment control measures. 3.10 STEP 10: EVALUATE JOB SITE TO DETERMINE FINAL STABILIZATION Final Stabilization shall be defined as the completion of all soil-disturbing activities and the two following criteria have been met:
A uniform (i.e., evenly distributed, without large bare areas) perennial vegetative cover with a density equivalent to 70% of the native background vegetative cover has been established on all unpaved areas and areas not covered by permanent structures. Where perennial vegetation is not yet fully established, temporary erosion control devices are properly installed and fully operational. Permanent erosion control measures (e.g., riprap, gabions, or geotextiles) have been employed and are fully operational.
Refer to Appendix A for methods for determining final stabilization for native seeded/unpaved areas. Responsibilities: ADOT: Determine final acceptance in accordance with the project specifications. The Contractor: Initiate inspections to determine if final stabilization has been achieved. 3.11 STEP 11: SUBMIT NOTICE OF TERMINATION (NOT) A complete and accurate NOT must be submitted to ADEQ after it has been determined that the project has met the submittal criteria as described in 3.10 above. The NOT form is available at the ADEQ website www.adeq.az.us or by calling 602-771-4665 or 4449.
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects
Submit form by certified mail or hand delivery to: Arizona Department of Environmental Quality Storm Water Program - Water Permits Section/NOT (5415B-3) 1110 W. Washington Street, Phoenix, AZ 85007 Responsibilities: ADOT: The Engineer is responsible for filling out, signing and submitting the NOT form for ADOT. The Contractor: The Contractor is responsible for submitting his own NOT form to ADEQ and providing one copy to the Engineer. In the case of an urban highway project where the landscape contract lags behind the paving project, the following rules apply for submitting the NOT:
If the bare ground is temporarily seeded and mulched as part of the paving project, ADOT and the contractor shall submit NOTs when the contract is complete. At the start of the subsequent landscape contract, both ADOT and the landscape contractor shall submit NOIs to obtain a new permit to cover the landscaping activities. If temporary seeding and mulching are not part of the paving project, ADOT cannot submit a NOT until after the completion of the landscaping project. Therefore, ADOT shall maintain temporary erosion and sediment controls in the area. ADOT shall also perform regular inspections (in accordance with the AZCGP) during the interim period after the paving project is complete and before the landscape contract begins. It should be noted that in this latter case, the paving contractor will submit a NOT at the end of the paving contract and the landscape contractor will submit a NOI before beginning subsequent work. In the interim, ADOT will have sole responsibility for the project.
3.12 STEP 12: RETENTION OF RECORDS ADOT and the Contractor shall retain copies of SWPPPs and all documentation required by this permit, including records of all data used to complete the NOI to be covered by this permit, for at least three years from the date of final stabilization of the site (AZCGP Part VI).
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.13 SPECIAL CONDITIONS, REQUIREMENTS AND EXCEPTIONS
C ondition, R equirement or E xception Permit Requirements for Tribal Trust Lands Action Permit must be obtained through the EPA Location of forms and further information EPA website: www.epa.gov http://cfpub.epa.gov/npdes/index.cfm ADOT Stored Specification 104SWEPA
Permit Requirements for discharge to unique or impaired waters
Follow instructions outlined in AZCGP and submit NOI, SWPPP and Monitoring Program 32 business days before construction activity will begin
AZCGP Part II.B.1 www.adeq.state.az.us This chapter - for AZCGP instructions Chapter 4 - for SWPPP preparation
Permit Requirements for Batch Plants, Borrow Pits and Material Pits located outside the right-of-way. Waivers for Small Construction Activities
Obtain permit coverage under Multi- www.adeq.state.az.us Sector General permit for AZCGP Part I.C.1.c for definition of construction activities not directly allowable discharges. related to a construction site. Determine if project equal to or greater than 1 acre but less than 5 acres is exempt from permit requirements AZCGP Part I.E and Part III.B
Table 3.3 Special Conditions, Requirements and Exceptions
3.13.1 Permit Requirements on Tribal Trust Lands If the project is located entirely on Tribal Trust Lands, permit coverage shall be obtained through the EPA (http://cfpub.epa.gov/npdes/index.cfm). Follow these steps (described in detail on the EPA website) and refer to the ADOT Stored Specification 104SWEPA to obtain coverage: Step 1: Read the FCGP and fact sheet. Step 2: Determine if project is eligible for coverage under the FCGP. Step 3: Develop and implement SWPPP (follow instructions in Chapter 4). Step 4: Complete and submit a NOI.
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3. Instructions for Obtaining a Construction General Permit for ADOT Projects Forms can be submitted by mail to: Storm Water Notice Processing Center Mail Code 4203M U.S. EPA 1200 Pennsylvania Avenue, NW Washington, DC 20460 Electronic NOI forms are available from the following website: http://cfpub.epa.gov/npdes/stormwater/enoi.cfm If the project site is located on the White Mountain Apache Reservation, the NOI shall be sent to: Tribal Environmental Planning Office P.O. Box 2109 Whiteriver, AZ 85941 3.13.2 Permit requirements for projects located within 1/4 mile of Impaired or Unique Waters. If the project site is located within � mile of unique (R18-11-112) or impaired (Section 303(d) of the CWA) waters, the NOI and the SWPPP must be submitted to ADEQ at least 32 business days before any construction activities occur at the site (AZCGP Part II.B.1). This extra time allows ADEQ to review the SWPPP to determine whether selected BMPs are sufficiently protective of water quality. The SWPPP must include a proposal for monitoring to determine if BMPs and controls are effective (AZCGP Part I.D.5.a). 3.13.3 Permit requirements for Batch Plants, Borrow Pits and Material Pits Discharges from support activities such as concrete or asphalt batch plants, equipment staging yards, material storage areas, screening and crushing plants, excavated material disposal areas and borrow areas are covered under the AZCGP if the conditions of the permit are followed (AZCGP Part I.C.1). The contractor must obtain coverage under a separate Multi-Sector General Permit (MSGP) for activities that do not fall under the allowable discharges for an AZCGP. 3.13.4 Waivers for Small Construction Activities Small Construction Activities, equal to or greater than 1 acre and less than 5 acres may be exempt from Arizona or Federal Construction General Permits if:
The project's rainfall erosivity factor calculation is less than 5 during the entire period of construction activity (AZCGP Part I.E.1) or, When an EPA-approved "total maximum daily load" indicates that receiving waters will not be impacted by discharges from the project (AZCGP Part I.E.2).
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4
STORM WATER POLLUTION PREVENTION PLANS (SWPPP)
Storm Water Pollution Prevention Plans (SWPPPs) are developed to describe operational activities and physical controls (BMPs) that will be used to prevent the discharge of pollutants into the waters of the United States. SWPPPs are site specific and, for ADOT construction projects, the contractor develops them as a first step in obtaining a CGP. A useful construction SWPPP checklist can be downloaded from the ADEQ website (www.adeq.state.az.us) and is included in Appendix A. The follow steps have www.adeq.state.az.us been developed to provide direction and resources to facilitate the completion of the SWPPP.
S tep Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7
Action Identify all operators for the Project Describe the Site and Prepare a Schedule of Construction Activities Select Controls to Reduce Pollutants Prepare a Plan for Maintenance of BMPs Collect Permit Related Documents Comply with Applicable Federal, State and Local Programs Develop a Site Specific Inspection Plan
AZC GP R eference Part IV.C Part IV.C Part IV.D Part IV.E Part IV.F Part IV.G Part IV.H
Information & forms
ADOT Standard Sheet Project Specifications Chapters 2 & 5 Appendix A
Chapter 1Design Documents ADOT AZPDES Inspection Checklist
4.1 STEP 1: IDENTIFY ALL OPERATORS FOR THE PROJECT An operator(s) is any person associated with the project who has control over the construction plans or specifications (ADOT) or day-to-day operational control of the site (the Contractor, the Erosion Control Coordinator, and any Subcontractor directly associated with installation or maintenance of BMPs). Operators certify the SWPPP (Chapter 3, Step 2) and are identified on the Standard "AZPDES SWPPP Index" Sheet in the erosion and sediment control plans developed by ADOT.
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4. Storm Water Pollution Prevention Plans (SWPP) 4.2 STEP 2: DESCRIBE THE SITE AND PREPARE A SCHEDULE OF CONSTRUCTION ACTIVITIES Much of the information needed to complete this portion of the SWPPP is included in the contract documents or in reports that are generated as part of the design process. These reports include the soils/geotechnical report, the project drainage report, and the environmental clearance documents and are available from ADOT. For larger projects, the project site may be divided into sub-areas based on the maximum allowable exposed area as specified in the project specifications. A schedule of construction activity shall be developed for each sub-area. 4.3 STEP 3: SELECT BMPS TO REDUCE POLLUTANTS To comply with Part IV.D of the AZCGP, the SWPPP must describe all BMPs that will be implemented as part of the construction project to control pollutants in storm water discharges. The SWPPP must clearly describe appropriate control measures to be used in each sub-area. Refer to the BMP descriptions in Chapter 5 when selecting appropriate permanent and temporary controls. As discussed in Section 3.1.1, ADOT will prepare Erosion and Sediment Control plans and details as part of the construction documents. These will provide direction and specific BMP expectations to the contractor. However, the project documents shall not be considered a complete SWPPP and shall not replace the contractor's SWPPP, since the project plans and details are prepared assuming standard construction practices and may not reflect the contractor's actual methods of construction, access requirements or project phasing. The contractor shall use the project plans as a guide in developing his own SWPPP. The SWPPP must also describe the "Good Housekeeping" procedures and practices as specified in the project specifications. These include: An inventory of chemicals and materials needed for construction. A spill prevention and clean-up plan; A description of storage, use and disposal of chemical and construction materials; A hazardous waste management plan; A solid waste management plan; and Sanitary/septic waste storage and disposal procedures.
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4. Storm Water Pollution Prevention Plans (SWPP)
4.4 STEP 4: PREPARE A PLAN FOR MAINTENANCE OF BMPS Proper maintenance of BMPs is an integral part of the effort to prevent storm water pollution. BMPs must be cleaned or replaced where design capacity is reduced by 50%. Procedures and activities for this purpose must be included in the SWPPP. Maintenance criteria are included in the BMP descriptions in Chapter 5. 4.5 STEP 5: COLLECT PERMIT-RELATED DOCUMENTS The following documents must be included in the SWPPP:
Document AZPDES permit (AZG2003-001) NOI (as completed by the contractor) NPDES or AZPDES authorization number for the project. Other agreements with any state, local or federal agencies that affect the provisions or implementation of the SWPPP. Part IV.J Part IV.J.2 Part IV.J.3 AZC GP R eferenc e S ource www.adeq.state.az.us www.adeq.state.az.us Provided by ADEQ after NOI is approved. ADOT environmental clearance documents.
In addition, a site specific inspection plan must be developed as part of the SWPPP. A standard ADOT inspection checklist is included in Appendix A. Identify and document the credentials of qualified inspectors. The credentials of a qualified inspector are described in the project specifications. 4.6 STEP 6: COMPY WITH APPLICABLE FEDERAL, STATE AND LOCAL PROGRAMS Chapter one described the federal, state and local soil and erosion control programs that must be followed to prevent pollution to the waters of the U.S. 4.7 STEP 7: DEVELOP A STE SPECIFIC INSPECTION PLAN An inspection plan must be developed as part of the SWPPP. A standard ADOT inspection checklist is included in Appendix A. Identify and show the credentials of qualified inspectors, as described in project specifications and in the SWPPP to simplify the completion of inspection reports in the field.
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5
BEST MANAGEMENT PRACTICES
5.0 INTRODUCTION ADOT requires contractors to prepare and implement a SSWPPP to control water pollution effectively during the construction process of all ADOT projects. As described in Chapter 4 of this manual, in order to complete the SWPPP for ADOT approval, the contractor is required to select those BMPs which will best control storm water pollution. This chapter provides instructions for the selection and implementation of BMPs. The BMPs described in this Chapter include both temporary and permanent erosion and sediment control practices. Each project presents unique conditions. These BMPs are provided as a "toolbox" to allow ADOT and the Contractor options to best address the requirements of the Arizona Construction General Permit. Disturbed Soil Area Management Limiting the amount of disturbed soil is a critical component in conducting an effective storm water management program. Section 104.09 of the Special Provisions states "Unless otherwise approved in writing, the contractor shall not expose an area greater than 750,000 square feet in any one location within the project limits until the erosion control devices proposed for that portion of the project have been installed and accepted by the Engineer.... In addition, unless otherwise approved by the Engineer, erosion control measures for each slope that is not scheduled to be re-disturbed within 21 days shall be placed not later than 14 days after construction activity has temporarily or permanently ceased for that portion of the work." The Engineer may elect to further restrict the size of the project's total disturbed area during the rainy season. 5.1 SOIL STABILIZATION BEST MANAGEMENT PRACTICES Soil stabilization consists of preparing the soil surface and applying one of the following BMPs, or a combination thereof, to disturbed soils areas. 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 5.1.7 5.1.8 5.1.9 Scheduling............................................................................. 36 Preserve Existing Vegetation..................................................38 Minibenches/Slope Roughening........................................... 40 Hydraulic Mulch.....................................................................44 Hydroseeding..........................................................................46 Soil Binders............................................................................48 Straw Mulch........................................................................... 54 Geotextiles, Plastic Covers, Erosion Control Blankets/Mats.............................................56 Compost/Wood Mulching.....................................................64
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Scheduling
5.1.1 Scheduling Definition The development of a schedule for every project that includes sequencing of construction activities in conjunction with the implementation of construction site BMPs in order to reduce the amount and duration of soil exposed by construction activities. The purpose is to minimize erosion of disturbed soils by wind, rain, runoff, and vehicle tracking. Purpose
To reduce the amount and duration of soil exposed to erosion. To ensure that BMPs are implemented in a timely manner as construction proceeds.
Appropriate Applications Construction activities shall be planned to minimize the amount of disturbed land exposed to erosive conditions. Stabilization measures shall be installed and maintained as work progresses, not just at the completion of construction.
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Planning Considerations Schedule the installation of temporary and permanent controls as specified in the Construction General Permit. The schedule of construction activities and concurrent application of temporary and permanent BMPs is developed as part of the SWPPP. Schedule clearing and grubbing activity to allow existing vegetation to remain in place as long as possible. For larger projects, the contractor shall not expose more than 750,000 square feet in any location until temporary or permanent BMPs have been installed. Schedule shall include dates for significant long-term operations or activities that may have planned non-storm water discharges such as dewatering, sawcutting, grinding, drilling, boring, crushing, blasting, painting, hydro-demolition, mortar mixing, bridge cleaning, etc. Schedule shall include dates for installation of permanent drainage systems and runoff diversion devices. These devices should be installed as early as possible in the construction process. The schedule shall include non-storm water BMPs, waste management and materials pollution control BMPs. Stabilize non-active areas as specified in the CGP. Monitor weather forecast and adjust construction schedule to allow for the implementation of soil stabilization and sediment controls on all disturbed areas prior to the onset of rain. Inspections
Verify that work is progressing in accordance with the schedule.
Maintenance The schedule must be updated when changes are warranted or when directed by the Engineer.
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Preserve Existing Vegetation
5.1.2 Preserve Existing Vegetation Definition The carefully planned protection of trees and natural vegetated areas within the construction site or right-of-way in order to minimize the amount of bare soil exposed to erosive forces and provide vegetated areas to filter storm water runoff. Purpose
Reduce soil erosion, sediment transport, and tracking. Reduce maintenance.
Appropriate Application Protect trees and natural areas not in direct conflict with construction activities. Limitations
Difficult on sites with restricted access. Requires planning and may limit area available for construction activity.
Standards and Specifications
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5. Best Management Practices Timing
Evaluate existing vegetation early in the planning process to adjust grading limits around high quality natural areas. Areas to be preserved in place shall be clearly marked at the site and identified on the project plans. Preservation of existing vegetation shall conform to scheduling requirements set forth in the special provisions. Clearing and grubbing and other soil-disturbing construction activities shall not be permitted prior to preservation of existing vegetation.
Design and Layout Areas to be preserved shall be marked with highly visible, non-metallic, temporary fencing as described in the project specifications. Temporary fencing shall be placed beyond the "dripline" of a tree by a distance that is 1� times the length of the "dripline" radius. Temporary roads shall be constructed to minimize disturbance to existing vegetation and remain within limits of disturbance of permanent road. Construction materials, equipment storage, and parking areas shall be located where they will not cause root compaction. Waste materials including vegetation to be removed shall not be stored within the preserved area. Construction Activities Where tree roots are disturbed, they shall be covered with soil as soon as possible. Damaged roots and limbs shall be cut cleanly. Seriously damaged trees shall be examined a trained arborist. Remove and replace trees if they are damaged seriously enough to affect their survival. Aerate soil where compaction occurs from construction activity. Immediately repair damage to irrigation systems. Inspections
Follow inspection schedule required in CGP Part IV.H. Inspect the preservation fencing to ensure that it is intact and that there has been no encroachment into the preservation area. Evaluate preserv-in-place vegetation for signs of stress.
Maintenance Maintain preservation fencing as needed. After all other work is complete, fencing and barriers shall be removed last. Address unhealthy and declining vegetation as described in project specifications.
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Minibenches/Slope Roughening
5.1.3
Minibenches/Slope Roughening
Definition Terracing and roughening are techniques for creating furrows, terraces, serrations, stair-steps or track-marks on the soil surface. Purpose
To improve water infiltration. To increase the effectiveness of temporary and permanent soil stabilization practices.
Appropriate Applications Large engineered slopes, primarily cuts in rural settings. Soils prone to erosion. Prior to application of permanent seeding. Limitations
Not appropriate on rock slopes. Must be constructed as slope is cut.
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Standards and Specifications Planning Considerations Minibenching and slope roughening shall be constructed from the top of a cut slope down. Design Minibenches, terraces, furrows, and other horizontal roughening techniques shall follow the contour. Inspections and Maintenance Follow inspection schedule required in the CGP Part IV.H. Where horizontal roughening falls away from the contour, additional BMPs may be required to protect the slope.
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Hydraulic Mulch
5.1.4
Hydraulic Mulch
Definition Hydraulic mulch consists of applying a mixture of shredded wood fiber or a hydraulic matrix (e.g., bonded fiber matrix), and a stabilizing emulsion or tackifier with hydro-mulching equipment. This will protect exposed soil from erosion by raindrop impact or wind. This is one of five temporary soil stabilization alternatives to consider. Purpose Reduce soil erosion through temporary stabilization. Appropriate Applications Temporary protection of disturbed areas until permanent measures (such as vegetation) are installed. Temporary protection of disturbed areas that must be re-disturbed following an extended period of inactivity. Hydraulic matrices typically are effective for longer periods of time. Limitations
Wood fiber hydraulic mulches are typically short-lived (less than a growing season). Hydraulic tackifiers typically require 24 hours to cure to be effective. Therefore,
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should not be applied immediately prior to a storm event. Standards and Specifications Apply as specified in project documents or by manufacturer. Soil surface must be loose at time of application. Area to be mulched shall be completely covered. Avoid overspray onto existing pavements, structures and vegetation. Selection of hydraulic mulches by the contractor must be approved by the Engineer prior to use. Inspections
Follow inspection schedule required in the CGP Part IV.H. Inspect after all rainfall events.
Maintenance Maintain an unbroken ground cover throughout the period of construction the soils are not being reworked.
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Hydroseeding
5.1.5
Hydroseeding
Definition Hydroseeding typically consists of applying a mixture of fiber, seed, fertilizer, and stabilizing emulsion with hydro-mulch equipment, which protects exposed soils from erosion by water and wind. This is one of five temporary soil stabilization alternatives to consider. Purpose Reduce soil erosion through temporary soil stabilization. Appropriate Applications Application of seed for permanent revegetation and stabilization of disturbed soils. Temporary protection of disturbed areas until permanent measures (e.g., vegetation) are installed. Temporary protection of disturbed areas that must be re-disturbed following an extended period of inactivity. Limitations
Straw mulching may be necessary in addition to hydroseeding in order to promote establishment of vegetation.
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Steep slopes are difficult to protect with temporary seeding. Dry or cold weather will affect vegetative establishment.
Standards and Specifications Site conditions must be evaluated prior to determining suitable species selection and application rates. Attributes such as soil types, topography, local climate and season, maintenance requirements, proximity of sensitive areas (e.g., live streams), and existing native vegetation types. Prior to use, ADOT shall approve application rates for mulches, tackifier, soil amendments and seed mixtures as per specifications prior to application. All seed shall be in conformance with requirements of the project specifications. Areas to be seeded shall be filled as described in project specifications. Soil shall be loose and friable. Inspections
Follow inspection schedule required in the CGP Part IV.H and project specifications.
Maintenance Any temporary revegetation efforts that do not provide adequate cover must be revegetated as required by the Engineer.
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Soil Binders
5.1.6
Soil Binders
Definition Soil binders consist of applying and maintaining polymeric or lignin sulfonate soil stabilizers or emulsions. Soil binders are materials applied to the soil surface to temporarily prevent waterinduced erosion of exposed soils on construction sites. Soil binders typically also provide dust, wind, and soil stabilization (erosion control) benefits. This is one of five temporary soil stabilization alternatives to consider. Purpose
Reduce soil erosion through temporary soil stabilization.
Appropriate Applications Temporary protection of disturbed areas until permanent measures (e.g., vegetation) are installed. Temporary protection of disturbed areas that must be re-disturbed following a period of inactivity. Because they can be often incorporated back into the work, they may be a good choice where grading activities will soon resume.
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Limitations
Soil binders are temporary in nature and may require reapplication, especially after heavy or prolonged rainfall. Typically require a cure time of approximately 24 hours. Easily disturbed by vehicular or pedestrian traffic. Do not adhere well to compacted or dense (clay) soils. May not perform well under conditions of low relative humidity or low temperatures. May be slippery if oversprayed onto vehicular travelways.
Standards and Specifications General Considerations Site conditions (soil type, temperature and humidity) must be evaluated prior to determining appropriate soil binder type. Regional soil types will dictate appropriate soil binders to be used. Must be environmentally benign (non-toxic to existing plants and wildlife). Selecting a Soil Binder Properties of common soil binders used for erosion control are provided on Table 5.1.6. In consultation with the Engineer, use Table 5.1.6 to select an appropriate soil binder. Factors to consider when selecting a soil binder include the following:
Suitability to situation � Consider where the soil binder will be applied: if it needs a high resistance to leaching or abrasion, and whether it needs to be compatible with any existing vegetation. Determine the length of time soil stabilization will be needed, and if the soil binder will be placed in an area where it will degrade rapidly. In general, slope steepness is not a discriminating factor for the listed soil binders. The soil binders in Table 5.1.6 may also be used for dust control using the provided dust control application rates. The dust control application rates will not be adequate to provide protection from water-induced erosion. Soil types and surface materials � Fines and moisture content are key properties of surface materials. Consider a soil binder's ability to penetrate, likelihood of leaching, and ability to form a surface crust on the surface materials. Frequency of application � The frequency of application can be affected by subgrade conditions, surface type, traffic volumes, climate, and maintenance schedule.
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Soil Binders
Frequent applications could lead to high costs. Application frequency may be minimized if the soil binder has good penetration, low evaporation, and good longevity. Consider also that frequent application will require frequent equipment clean-up. After considering the above factors, the soil binders in Table 5.1.6 will be generally appropriate as follows: Copolymer: Appropriate for long term soil stabilization in areas where cross-traffic might occur, or where stabilization needs to be achieved in conjunction with preserving existing vegetation. Longevity can be up to 2 years, it has a high resistance to abrasion, and is compatible with existing vegetation. However, it is also relatively costly which makes it less desirable for short-term or frequent applications. Lignin sulfonate: Appropriate for short- or medium-term soil stabilization applications in low traffic areas. The moderate relative cost makes it less desirable to reapply frequently, though it typically lasts longer than psyllium or guar. With only moderate penetration and a low resistance to abrasion, it would be more suited to areas which will not be disturbed frequently by construction activities. Psyllium/Guar: Appropriate for typical soil stabilizing situations or short-term applications. Because of the relatively low cost, they can be applied more frequently. Their high penetration provides good stabilization but their moderate resistance to abrasion limits their longevity. They are not very compatible with vegetation. Applying Soil Binders After selecting an appropriate soil binder, the untreated soil surface must be prepared before applying the soil binder. The untreated soil surface must contain sufficient moisture to assist the agent in achieving uniform distribution. In general, the following steps shall be followed:
Follow manufacturer's recommendations for application rates, pre-wetting of application area and cleaning of equipment after use. Prior to application, roughen embankment and fill areas. Track walking shall only be used where rolling is impractical. Soil binders shall not be applied during or immediately before rainfall. Avoid over-spray onto the traveled way, sidewalks, lined drainage channels, sound walls, and existing vegetation. Do not apply soil binders to frozen soil, areas with standing water, under freezing or rainy conditions, or when temperature is below 4 � (40�F).
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More than one treatment is often necessary, although the second treatment may be diluted or have a lower application rate. Generally, soil binders require a minimum curing time of 24 hours before they are fully effective. Refer to manufacturer's instructions for specific cure times.
For liquid agents: Crown or slope ground to avoid ponding. Uniformly pre-wet ground at 0.14 to 1.4 l/m� (0.03 to 0.3 gal/yd�) or according to manufacturer's recommendations. Apply solution under pressure. Overlap solution 150 to 300 mm (6 to 12 inches). Allow treated area to cure for the time recommended by the manufacturer, typically, at least 12 hours. Apply second treatment before the first treatment becomes ineffective, using 50% application rate. In low humidities, reactivate chemicals by re-wetting with water at 0.5 to 0.9 l/m� (0.1 to 0.2 gal/yd�). Maintenance and Inspection Reapplying the selected soil binder may be needed for proper maintenance. High traffic areas shall be inspected on a daily basis, and lower traffic areas should be inspected on a weekly basis. After any rainfall event, the Contractor is responsible for maintaining all slopes to prevent erosion.
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Soil Binders
Properties of Soil Binders for Erosion Control
C hemicals C opolymer - Forms semipermeable transparent crust. - Resists ultraviolet radiation and moisture induced breakdown High Low Moderate Moderate Low High 1 to 2 years 24 hours Lignin S ulfonate - Paper industry waste produce - Acts as dispersing agent- Best in dry climates- Can be slippery Moderate Low Moderate Moderate High Low 6 months to 1 year 24 hours P oor Ps yllium Guar
Comments
- Effective on dry, hard soils - Forms a crust
- Effective on dry, hard soils - Forms a crust
Relative Cost Environmental Hazard Penetration Evaporation Resistance to Leaching Resistance to Abrasion Longevity Minimum Curing Time before Rain
Low Low High Moderate High Moderate 3 to 6 months 24 hours P oor
Low Low High Moderate High Moderate 3 to 6 months 24 hours P oor Biologically Degradable No Yes Powder Yes, but dissolves on rewetting Water Apply 110-220 kg/ha (100-200 lbs./ac) with 5602,200 kg/ha (5002,000 lbs./ac) fiber mulch. Apply at 45-70 K/ha (40-60 lbs./ac).
Compatibility with Good Existing Vegetation Mode of Degradation Labor Intensive Specialized Application Equipment Liquid/Powder Surface Crusting Clean-Up Chemically Degradable No Yes Liquid Yes Solvents
Biologically/PhysicallBiologically y/Chemically Degradable Degradable No Yes Powder No Yes Powder
Yes, but dissolves on Yes, but dissolves rewetting on rewetting Solvents Water
Erosion Control Application Rate
Apply 170 kg/ha (150 lb./ac) with Apply 800-1,000I/ha Apply 5,600-6,500 560-2,200 kg/ha (85-110 gal/ac). I/ha (600-700 gal/ac). (500-2,000 lbs./ac) fiber mulch. Loosen surface 2550mm (1-2 in). Need Apply 280-520 L/ha Apply 170 K/ha 4-8% fines. Apply (30-55 gal/ac). (150 lbs./ac). 470-1,900 l/ha (50200 gal/ac).
Dust Control Application Rate
Table 5.1.6
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Straw Mulch
5.1.7
Straw Mulch
Definition Straw mulch consists of placing a uniform layer of straw and incorporating it into the soil by mechanical means (e.g., a drill or studded roller) or anchoring it with tackifier. This is one of five temporary soil stabilization alternatives to consider. Purpose
Reduce soil erosion through temporary soil stabilization.
Appropriate Applications Straw mulch is used for soil stabilization as a temporary surface cover on disturbed areas until soils can be prepared for final stabilization. Typically used in combination with temporary and/or permanent seeding applications to enhance plant establishment. Limitations
Where mechanical straw blowers are used, application areas are typically limited to within approximately 150 feet of equipment. Therefore, for large slopes frequent mobilizations and applications are necessary. Application of straw mulch by hand is typically expensive.
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Potential for accidental introduction of undesirable weed species. Blown straw is potentially a nuisance when applied in urban areas.
Standards and Specifications Materials shall conform to and shall be applied at rates specified in special provisions. Straw shall be certified to be free of weeds and invasive species. When applied by blower, avoid overspray onto existing pavements, structures and vegetation. On slopes less steep than 2 (horizontal): 1 (vertical) and where mechanical action will not contribute to soil compaction, straw can be "punched" into the soil using a knife-blade roller or a straight bladed coulter ("crimper"). For small areas, straw can be anchored by hand tools. Inspections
Follow inspection schedule required in the CGP Part IV.H.
Maintenance Reapply mulch when more than 20% bare ground is exposed in application area.
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Geotextiles, Plastic Covers, Erosion Control Blankets/Mats
5.1.8
Geotextiles, Plastic Covers and Erosion Control Blankets/Mats
Definition A natural (excelsior, straw, coconut, etc.) or synthetic (usually polyethelene) material installed to reduce soil erosion by wind or water. This is one of five soil stabilization alternatives to consider. Purpose
Reduce rainfall impact. Provide a microclimate to promote seedling establishment. Protect exposed soil from wind and rain. Reduce erosiveness of concentrated flows.
Appropriate Applications Steep slopes (typically greater than 3 horizontal: 1 vertical). Slopes with highly erosive soils or where the erosion hazard is high. Slopes adjacent to bodies of water. Concentrated flow areas such as ditches and channels with flows exceeding 3.3 ft/ sec. (refer to ADOT Hydraulic Manual for channel lining criteria). In areas where plant establishment is likely to be slow. Areas inaccessible to hydraulic equipment.
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Stockpiles. Costly. Not suitable for excessively rocky sites or rough slopes. Not suitable for areas where vegetation will be mowed. Plastic sheeting is easily disturbed and must be removed and disposed of prior to Application of permanent soil stabilization measures. Plastic also results in increased runoff rates. May trap wildlife.
Limitations
Standards and Specifications Material Selection There are a wide variety of types and materials from which to choose. Selection shall be based on needs for the specific project. Factors to consider include: Cost: materials, site preparation, installation. Effectiveness: reduction of erosion, flow velocity, and runoff. Acceptability: environmental compatibility, regulatory, and aesthetic concerns. Vegetation enhancement: moisture retention, temperature modification. Installation: durability, longevity, ease of installation, safety. Maintenance. Geotextiles: Material shall be woven polypropylene fabric with minimum thickness of 0.5 inches, minimum width of 12 feet and shall have minimum tensile strength of 50 lbs/ ft (0.67 kN) (warp) 25 lbs/ ft. (0.36 kN) (fill) in conformance with the requirements in ASTM Designation: D 4632. The permittivity of the fabric shall be approximately 0.07 sec-� in conformance with the requirements in ASTM Designation: D4491. The fabric shall have an ultraviolet (UV) stability of 70 percent in conformance with the requirements in ASTM designation: D4355. Geotextile blankets shall be secured in place with wire staples or sandbags and by keying into tops of slopes to prevent infiltration of surface waters under Geotextiles may be reused if, in the opinion of the RE, they are suitable for the use intended.
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Geotextiles, Plastic Covers, Erosion Control Blankets/Mats
Plastic Covers: Material shall be polyethylene sheeting and shall have a minimum thickness of 6 mm. Plastic covers shall be anchored by sandbags placed no more than 10 feet apart and by keying into the tops of slopes to prevent infiltration of surface waters under the plastic. All seams shall be taped or weighted down their entire length, and there shall be at least 12 inches to 24 inches overlap of all seams. Plastic covers may be reused if, in the opinion of the engineer, they are suitable for the use intended. Erosion Control Blankets/Mats: Blankets and Mats are available in materials with a wide variety of susceptibility to biological and photo-degradation. The most common materials in order of least to most durable are: Agricultural straw. Jute fiber. Wood fiber (Excelsior). Coconut fiber (coir). Site Preparation Proper site preparation is essential to ensure complete contact of the blanket or matting with the soil. Grade and shape the area of installation. Remove all rocks, clods, vegetation or other obstructions so that the installed blankets or mats will have complete, direct contact with the soil. Contractor shall cut material to fit around large boulders. If areas is to be seeded, prepare soil as directed in the project specifications before applying covering. Seeding Seed the area before blanket installation for erosion control and revegetation. Seeding after mat installation is often specified for turf reinforcement application. When seeding prior to blanket installation, all check slots and other areas disturbed during installation must be re-seeded. Where soil filling is specified, seed the matting and the entire disturbed area after installation and prior to filling the mat with soil. Anchoring
U-shaped wire staples, metal pins or wooden stakes can be used to anchor mats and blankets to the ground surface. Staples shall be made of .12 inch steel wire and shall be U-shaped with 8-inch legs and 2-inch crown. Wire staples shall be minimum of 11 gauge.
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Metal stake pins shall be 0.188-inch diameter steel with a 1.5 inch steel washer at the head of the pin. Wire staples and metal stakes shall be driven flush to the soil surface. All anchors shall have sufficient ground penetration to resist pullout by wind. Longer anchors may be required for loose soils.
Installation on Slopes Always consult the manufacturer's recommendations for installation. In general, these will be as follows: 1. Begin at the top of the slope and anchor the blanket in a 12-inch deep trench. Backfill trench, tamp earth firmly and staple every 12 inches. 2. Unroll blanket downslope in the direction of water flow. 3. Overlap the edges of adjacent parallel rolls 4 inches and staple every 12 inches. 4. When blankets must be spliced, place blanket ends in common trench as described above with 6-inch overlap. Staple through overlapped area, approximately 6 inches apart. 5. Lay blankets loosely and maintain direct contact with the soil. Do not stretch. 6. Staple blankets sufficiently to anchor blanket and maintain contact with the soil. Staples shall be placed down the center and staggered with the staples placed along the edges. 7. On steep slopes, 1:1 (V:H) to 1:2 (V:H), require a minimum of 2 staples/yd�. Moderate slopes, 1:2 (V:H) to 1:3 (V:H), require a minimum of 1 � staples/yd�, placing 1 staple/yd on centers. Gentle slopes require a minimum of 1 staple/yd�. Installation in Channels Always consult the manufacturer's recommendations for installation. In general, these will be as follows: 1. Dig initial anchor trench 12 inches deep and 6 inches wide across the channel at the lower end of the project area. 2. Excavate intermittent check slots, 6 inches deep and 6 inches wide across the channel at 25- to 30 foot-intervals along the channels. 3. Cut longitudinal channel anchor slots 4 inches deep and 4 inches wide along each side of the installation to bury edges of matting, whenever possible extend matting 2 inches to 3 inches above the crest of the channel side slopes. 4. Beginning at the downstream end and in the center of the channel, place the initial end of the first roll in the anchor trench and secure with fastening devices at 12 inches intervals. Note: matting will initially be upside down in anchor trench. 5. In the same manner, position adjacent rolls in anchor trench, overlapping the preceding roll a minimum of 3 inches.
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Geotextiles, Plastic Covers, Erosion Control Blankets/Mats
6. Secure these initial ends of mats with anchors at 12-inch intervals, backfill and compact soil.Unroll center strip of matting upstream. Stop at next check slot or terminal anchor trench. Unroll adjacent mats upstream in similar fashion, maintaining a 3-inch overlap. Fold and secure all rolls of matting snugly into all transverse check slots. Lay mat in the bottom of the slot then fold back against itself. Anchor through both layers of mat at 12-inch intervals, then backfill and compact soil. Continue rolling all mat widths upstream to the next check slot or terminal anchor trench.
7.
Alternate method for non-critical installations: 1. Place two rows of anchors on 6-inch centers at 25- to 30-foot intervals in lieu of excavated check slots. 2. Shingle-lap spliced ends by a minimum of 12 inches apart on 12-inch intervals. 3. Place edges of outside mats in previously excavated longitudinal slots, anchor using prescribed staple pattern, backfill and compact soil. 4. Anchor, fill and compact upstream end of mat in a 12 inches by 6 inches terminal trench. 5. Secure mat top ground surface using U-shaped wire staples, geotextile pins, or wooden stakes. 6. Seed and fill turf reinforcement matting with soil, if specified. Soil filling (if specified for turf reinforcement) Always consult the manufacturer's recommendations for installation. Do not drive tacked or heavy equipment over mat. Avoid any traffic over matting if loose or wet soil conditions exist. Use shovels, rakes or brooms for fine grading and touch up. Smooth out soil filling; just exposing top netting of mat. Removal When no longer required for the work, coverings shall become the property of the Contractor and shall be disposed of outside the highway right of way in conformance with the special provisions. Inspections
Follow inspection schedule required in CGP Part IV.H. Erosion may occur under blankets in areas were contact with soil has been compromised. This damage may be difficult to detect and repair.
Maintenance Re-anchor loosened matting and replace lost matting and staples as required. Repair slope or channel damage before re-installing matting if washout or breakage occurs.
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Compost/Wood Mulching
5.1.9
Compost/Wood Mulching
Definition Compost or wood mulching consists of applying a mixture of compost, shredded wood mulch or bark. Purpose
To temporarily protect exposed soil from wind, raindrop impact, increase infiltration and reduce runoff. To provide a suitable microclimate to promote seed germination. To prevent surface compaction or crusting.
Appropriate Applications Temporary soil stabilization. Shredded bark mulch may be applied to smaller drainage channels to reduce runoff velocities and soil erosion. Sensitive areas may be mulched at the end of a day's operations if rain is predicted. In conjunction with seed to encourage seed germination and establishment.
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Mulches that are susceptible to erosion by wind or water are anchored to the soil using a variety of techniques. Crimping, tracking, disking or punching. Hydraulic bonding using a variety of organic or acrylic tackifiers. Covering with netting and stapled Limitations
Susceptible to wind disturbance. Potential for accidental introduction of undesirable weed species. Areas where hydraulically bonded mulches are to be applied must be accessible to equipment used in the process. Hydraulically bonded mulches require 24 hours to dry before rainfall occurs to be effective. Shredded wood mulch will not withstand significant concentrated flows and is prone to sheet erosion.
Standards and Specifications Mulch Selection There are many different types of mulches. Selection on type shall be based on type of application and site conditions. Prior to use, choice of mulch shall be approved by the Landscape Architect. Shredded wood and wood chips)�may be available from existing suitable vegetation to be cleared from site. Compost � typically applied as a component of seeding applications; shall be tested as described in the special provisions for biotic and abiotic factors. Installation
May be applied by hand or by mechanical or hydraulic methods. Follow inspection schedule required in CGP Part IV.H. Inspect for exposed areas of soil or where covering is broken.
Inspections
Maintenance Reapply mulch when more than 20% bare ground is exposed in application area.
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5.2 CONCENTRATED FLOW CONVEYANCE CONTROLS Temporary concentrated flow conveyance controls consist of a system of installations or BMPs that are used alone or in combination to intercept, divert, convey, and discharge concentrated flows with a minimum of soil erosion, both on-site and downstream (offsite). Temporary concentrated flow conveyance controls may be required to direct run-on around or through the project in a non-erodible fashion. Temporary concentrated flow conveyance systems include the following BMPs: 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 Earth Dikes/Drainage Swales................................................ 68 Cut to Fill Slope Transitions................................................ 70 Erosion Protection at Structures.............................................72 Rock Outlet Protection.......................................................... 74 Slope Drains.......................................................................... 76
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Earth Dikes/Drainage Swales
5.2.1
Earth Dikes/Drainage Swales
Definition Structures that intercept, divert, and convey surface runoff (generally sheet flow) to a desired location. Purpose
To divert runoff away from erodible surfaces. To divert runoff toward sediment trapping devices.
Appropriate Applications At the base of fill slopes where runoff begins to concentrate. At the top of slopes to control rill and gully erosion. At bottom and mid-slope locations to intercept sheet flow and convey concentrated flows. To divert runoff toward a stabilized watercourse or drainage structure. To divert sediment laden water to sediment trapping device. To divert storm water around construction staging areas.
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5. Best Management Practices
Limitations
Runoff must be diverted into existing or stabilized drainages or sediment basins. High runoff velocities may scour and erode dikes and swales. May be necessary to combine with other BMPs such as check dams, blankets, and sediment logs or riprap. Does not control erosion or remove sediment.
Standards and Specifications Must be sized correctly for expected flows. Swales shall be lined where high runoff velocities are expected. Dikes shall be stabilized by compaction or other means such as erosion control blankets or riprap. Provide stabilized outlets. Where runoff will carry sediment, divert flow into sediment traps. Where installed at construction traffic crossings, the top width may be wider and side slopes may be flatter. When possible, dikes and swales shall be installed early in the construction process. Shall not adversely impact adjacent properties and must conform to local floodplain management regulations. Inspections
Follow inspection schedule required in CGP Part IV.H. Inspect for washouts and failure of associated BMPs. Check outlet stabilization for signs of erosion.
Maintenance Repair as needed. Repair where damaged by construction equipment. If material is added to repair the dike it must be properly recompacted. Where flows are directed into sediment traps, maintain as described in Sediment Trap BMP.
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Cut to Fill Slope Transitions
5.2.2
Cut to Fill Slope Transitions
Definition Rock riprap placed in cut-to-fill slope transitions. Purpose
To reduce erosion at cut-to fill transitions.
Appropriate Applications Where concentrated surface flows must be conveyed from a cut ditch, down to the toe of the adjoining downstream fill slope. Limitations
Rock riprap transitions reduce erosion only when they have been sized and built properly.
Standards and Specifications Width of riprap application at beginning of the cut-to-fill transition shall match width of roadside ditch. Width of rock riprap at end of cut-to-fill transition shall be 50% greater than the width of rock riprap at the beginning of the cut-to-fill transition.
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Cut-to-fill transition shall terminate at a planned or existing stabilized drainage. Rock shall be placed by hand or mechanical means to achieve complete coverage at the transition. Dumping of riprap may be necessary. Riprap shall be embedded into slopes. Riprap shall be placed to ensure that the center of the transition is lower than the edges and avoid runoff flow over unprotected soil. Size of rock used must be large enough to withstand expected design flow through the transition. Riprap greater than 6 inches shall be wire-tied if required by traffic recovery area.
Inspections and Maintenance Follow inspection schedule required in the CGP Part IV.H. Inspect for signs of slope erosion under and around the rock protection, check for erosion and displacement of rock at the outlet. Replace rock and repair as needed.
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Erosion Protection at Structures
5.2.3
Erosion Protection at Structures
Definition Rock riprap place along soil interface of concrete and metal structures Purpose
To reduce or eliminate the potential for undercutting at structures.
Appropriate Applications Place at any structure that abuts a soil surface and where concentration and/or velocity of storm water is great enough to cause erosive flows. Limitations
None
Planning Considerations Rock interface protection is effective when the rock is sized and placed properly. Standards and Specifications Design and size as specified in the contract documents or as directed by the Engineer.
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5. Best Management Practices
Use sound, durable, and angular rock for best results. Follow inspection schedule required in the CGP Part IV.H. Inspect for signs of erosion and undercutting around the structure.
Inspections
Maintenance Replace rock and repair erosion damage as needed.
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Rock Outlet Protection
5.2.4
Rock Outlet Protection
Definition Rock riprap or grouted riprap placed at outlets ends of culverts, conduits, or channels. Purpose
To prevent scour and reduce velocity of exiting storm water flows.
Appropriate Applications Where discharge velocities and energies at the outlets of culverts, pipes or channels are sufficient to erode the downstream channel. At discharge outlets that carry continuous flows of water. At points where lined conveyances discharge to unlined conveyances. Limitations
Loose rock may be washed away during high flows. Freeze/thaw cycles may break up grouted riprap.
Standards and Specifications
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Grouted or wire-tied rock riprap can minimize maintenance requirements. Rock must be sized and placed properly to be effective. Refer to ADOT Drainage Manual. A sediment trap below the outlet is recommended if runoff is sediment-laden. Use sound, durable and angular rock for best results. Follow inspection schedule required in the CGP Part IV.H. Inspect for displacement of riprap or damage to underlying fabric, and signs of scour beneath the riprap or around the outlet.
Inspections
Maintenance Replace rock and repair apron and slopes as needed.
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Slope Drains
5.2.5
Slope Drains A temporary drain used to intercept and convey runoff into a stabilized drainage.
Definition
Purpose
To prevent soil erosion.
Appropriate Applications Installed where slopes may be eroded by surface runoff. Typically used in conjunction with top of slope diversion berms, dikes or swales or temporary embankment curbs. Where final road grades are completed but remain unpaved. May be used as emergency spillway for sediment basin. Limitations
Volume of runoff to be conveyed must not exceed capacity of structure. Larger areas require a paved spillway, rock lined channel or additional pipes. May become clogged or overcharged during large storms forcing water around pipe. Failure causes extreme slope erosion.
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Standards and Specifications Design and Layout Size of area to be drained must be taken into consideration. Typically, no more than 5 acres shall be drained by one pipe. For larger areas, use a rock-lined channel or a series of pipes. Direct runoff into stabilized drainages. Inlet installation is critical because it is a common point of failure. Consider use of erosion control blanket at inlets. Outfall must be protected by riprap. For that reason, installation is typically limited to maximum grades of 2:1(v:h). Installation on steeper slopes is difficult. Consider flared end section for high volume discharges. Slope drains can be placed on the surface of slopes or installed below grade. Recommended materials for pipes are PVC, ABS or comparable. If a pipe slope drain is conveying sediment-laden water all flows shall be directed into a sediment-trapping device. Installation
Install as directed in contract documents. Drains shall be perpendicular to slope contours. All slope drain pipe sections shall be securely fastened together with a watertight seal and shall be securely anchored into the soil. Follow requirements for diversion dikes/swales to construct diversions used to direct runoff into a slope drain. Compact soil around and under inlet, outlet, and along length of pipe. The area below the outlet must be stabilized with a riprap apron. Refer to Erosion Protection and Structures Detail E-2. Follow inspection schedule required in Construction General Permit Part IV.H. Inspect for structural integrity, blockage, and stability at the inlet and outlet. Inspect for downstream scour; remedy as required.
Inspections
Maintenance Reinforce inlet with compacted soil or sandbags if problems occur. If outlet flow is directed to a sediment-trapping device, sediment should removed as specified in for that device.
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5.3 SEDIMENT CONTROL BEST MANAGEMENT PRACTICES Temporary sediment control practices include those measures that intercept and slow or detain the flow of storm water to allow sediment to settle and be trapped and include the following BMPs: 5.3.1 Sediment Control Berm..........................
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| Rating | |
| TITLE | ADOT erosion and pollution control manual for highway design and construction |
| CREATOR | Wheat Scharf Associates |
| SUBJECT | Roads--Environmental aspects--Arizona--Handbooks, manuals, etc.; Soil conservation--Arizona--Handbooks, manuals, etc.; Road drainage--Arizona--Handbooks, manuals, etc.; Water--Pollution--Arizona--Handbooks, manuals, etc.; |
| Browse Topic |
Transportation Land and resources |
| DESCRIPTION | 214 pages (PDF version). File size: 13343.821 KB. |
| Language | English |
| Contributor | Arizona Dept. of Transportation. Intermodal Transportation Division. |
| Publisher | Arizona Dept. of Transportation. Intermodal Transportation Division. |
| TYPE | Text |
| Material Collection |
State Documents |
| Acquisition Note | Publication or link to publication sent to reports@lib.az.us |
| RIGHTS MANAGEMENT | Copyright to this resource is held by the creating agency and is provided here for educational purposes only. It may not be downloaded, reproduced or distributed in any format without written permission of the creating agency. Any attempt to circumvent the access controls placed on this file is a violation of United States and international copyright laws, and is subject to criminal prosecution. |
| DATE ORIGINAL | 2005-02-01 |
| Time Period |
2000s (2000-2009) |
| ORIGINAL FORMAT | Born digital |
| Source Identifier | TRT 7.2:E 65/2005 |
| Location | 228300393 |
| DIGITAL IDENTIFIER | Erosion_and_Pollution_Control_Manual_020105.pdf |
| DIGITAL FORMAT | PDF (Portable Document Format) |
| REPOSITORY | Arizona State Library. Archives and Public Records--Law and Research Library. |
| File Size | 13343.821 KB |
| Full Text | As submitted to ADEQ on 2/1/2005. Document is subject to modification and will be updated as deemed necessary. ADOT EROSION AND POLLUTION CONTROL MANUAL For Highway Design and Construction Arizona Department of Transportation Intermodal Transportation Division ADOT EROSION AND POLLUTION CONTROL MANUAL Wheat Scharf Associates ADOT Erosion and Pollution Control Review Committee Joseph Salazar Roadside Development Section Zitao Fang Roadside Development Section Andrew Roth Prescott District Kirk Kiser Phoenix Construction District Colleen Kelley EcoPlan Associates Terry Brennan Tonto National Forest for the under the direction of Written and Edited by LeRoy Brady Roadside Development Section Matthew Walkowiak Phoenix Construction District Michael Mingo Natural Resources Rob Ingram Tonto National Forest Ted Littlefield Construction Operations Arizona Department of Transportation, Intermodal Transportation Division Wheat Scharf Associates ADOT Roadside Development Section February 2005 Arizona Department of Transportation, Intermodal Transportation Division Roadside Development Section 205 S. 17th Avenue, MD 617E Phoenix, Arizona 85007 Produced and Published by and Photography and Graphics by TABLE OF CONTENTS 1 INTRODUCTION 1.1 PURPOSE OF MANUAL ............................................................................................................ 3 1.2WATER QUALITY REGULATIONS AND PERMITS ............................................................ 3 1.2.1 Arizona Department of Environmental Quality's (ADEQ's) Arizona Pollution Discharge Elimination System (AZPDES) Storm Water Permit Requirements. ................... 4 1.2.2 Federal Highway Administration Erosion Control Guidelines ..................................... 5 1.2.3 Section 404 of the Clean Water Act .............................................................................. 5 1.2.4 Section 401 of the Clean Water Act .............................................................................. 6 1.2.5 Additional Federal Land Requirements ........................................................................ 7 1.2.6 State and Local Government and Agency Requirements ............................................. 8 1.3BEST MANAGEMENT PRACTICE (BMP) SELECTION AND DESIGN ........................... 9 2 PROJECT PLANNINGAND DESIGN GUIDE 2.1 OVERVIEW ................................................................................................................................ 10 2.2 PROJECT PLANNING AND DESIGN ..................................................................................... 11 2.2.1. Evaluate Increased Runoff Flows .............................................................................. 11 2.2.2 Preservation of Existing Vegetation............................................................................ 12 2.2.3 Concentrated Flow Structures .................................................................................... 13 2.2.3.1 Ditches and Dikes .................................................................................................... 13 2.2.3.2 Overside Drains ....................................................................................................... 16 2.2.3.3 Culvert and Channel Outlets ................................................................................... 16 2.2.4 Slope Protection.......................................................................................................... 17 2.2.4.1 Vegetated Surfaces ................................................................................................... 17 2.2.4.2 Hard Surfaces .......................................................................................................... 18 2.2.4.3 Erosion and Sediment Control Plans and Details .................................................... 18 3 INSTRUCTIONS FOR OBTAINING ARIZONA OR FEDERAL CONSTRUCTION GENERAL PERMIT AUTHORIZATION FOR ADOT CONSTRUCTION PROJECTS 3.1 PREPARE A STORM WATER POLLUTION PREVENTION PLAN (SWPPP) ................ 20 3.1.1 Project Document BMPs ............................................................................................ 20 3.2 CERTIFY THE SWPPP............................................................................................................. 20 3.3 SUBMIT NOTICE OF INTENT (NOI) .................................................................................... 21 ADOT Erosion and Pollution Control Manual For Highway Design and Construction ii 3.4 RETAIN THE NOI AND THE SWPPP AT THE JOB SITE ................................................. 23 3.5 IMPLEMENT THE SWPPP ..................................................................................................... 23 3.6 INSPECT THE BMPS REGULARLY ..................................................................................... 24 3.7 ADJUST THE SWPPP TO FIT SITE CONDITIONS ............................................................ 27 3.8 MAINTAIN AN UPDATED SWPPP ........................................................................................ 27 3.9 MAINTAIN THE BMPS ............................................................................................................ 27 3.10 EVALUATE JOB SITE TO DETERMINE FINAL STABILIZATION .............................. 28 3.11 SUBMIT NOTICE OF TERMINATION (NOT) ................................................................... 28 3.12 RETENTION OF RECORDS ................................................................................................. 29 3.13 SPECIAL CONDITIONS, REQUIREMENTS AND EXCEPTIONS ................................. 30 3.13.1 Permit Requirements on Tribal Trust Lands ............................................................. 30 3.13.2 Permit requirements for projects located within 1/4 mile of Impaired or Unique Waters. ................................................................................................................................. 31 3.13.3 Permit requirements for Batch Plants, Borrow Pits and Material Pits ..................... 31 3.13.4 Waivers for Small Construction Activities ............................................................... 31 4 STORM WATER POLLUTION PREVENTION PLANS (SWPPP) 4.1 IDENTIFY ALL OPERATORS FOR THE PROJECT .......................................................... 32 4.2 DESCRIBE THE SITE AND PREPARE A SCHEDULE OF CONSTRUCTION ACTIVITIES ................................................................................................................................................... 33 4.3. SELECT BMPS TO REDUCE POLLUTANTS ..................................................................... 33 4.4 PREPARE A PLAN FOR MAINTENANCE OF BMPS ......................................................... 34 4.5 COLLECT PERMIT-RELATED DOCUMENTS ................................................................... 34 4.6 COMPLY WITH APPLICABLE FEDERAL, STATE AND LOCAL PROGRAMS........... 34 4.7 DEVELOP A SITE SPECIFIC INSPECTION PLAN ............................................................ 34 5 TEMPORARY BEST MANAGEMENT PRACTICES 5.0 INTRODUCTION ..................................................................................................................... 35 Disturbed Soil Area Management ........................................................................................ 35 5.1 SOIL STABILIZATION BEST MANAGEMENT PRACTICES .......................................... 35 5.1.1 Scheduling .................................................................................................................. 36 5.1.2 Preserve Existing Vegetation ...................................................................................... 38 5.1.3 Minibenches/ Slope Roughening ................................................................................ 40 5.1.4 Hydraulic Mulch ......................................................................................................... 44 5.1.5 Hydroseeding .............................................................................................................. 46 5.1.6 Soil Binders ................................................................................................................ 48 ADOT Erosion and Pollution Control Manual For Highway Design and Construction iii 5.1.7 Straw Mulch ............................................................................................................... 54 5.1.8 Geotextiles, Plastic Covers and Erosion Control Blankets/ Mats .............................. 56 5.1.9 Compost/ Wood Mulching .......................................................................................... 64 5.2 CONCENTRATED FLOW CONVEYANCE CONTROLS .................................................. 67 5.2.1 Earth Dikes/Drainage Swales ..................................................................................... 68 5.2.2 Cut to Fill Slope Transitions ....................................................................................... 70 5.2.3 Erosion Protection at Structures ................................................................................. 72 5.2.4 Rock Outlet Protection ............................................................................................... 74 5.2.5 Slope Drains ............................................................................................................... 76 5.3 SEDIMENT CONTROL BEST MANAGEMENT PRACTICES ......................................... 79 5.3.1 Erosion Control Berm................................................................................................. 80 5.3.2 Silt Fence .................................................................................................................... 84 5.3.3 Desilting Basin/ Sediment Trap .................................................................................. 88 5.3.4 Check Dams ................................................................................................................ 92 5.3.5 Sediment Wattles ........................................................................................................ 96 5.3.6 Sediment Logs .......................................................................................................... 100 5.3.7 Street Sweeping and Vacuuming .............................................................................. 104 5.3.8 Sand Bag Barrier ....................................................................................................... 106 5.3.9 Storm Drain Inlet Protection......................................................................................110 5.3.10 Curb Inlet Protection ............................................................................................... 116 5.4 WIND EROSION CONTROL BEST MANAGEMENT PRACTICES ............................... 119 5.4.1 Wind Erosion Control ............................................................................................... 120 5.5 TRACKING CONTROL BEST MANAGEMENT PRACTICES ....................................... 123 5.5.1 Stabilized Construction Entrance/Exit ..................................................................... 124 5.5.2 Stabilized Construction Roadway ............................................................................ 126 5.6 NON-STORM WATER BEST MANAGEMENT PRACTICES .......................................... 129 5.6.1 Water Conservation Practices ................................................................................... 130 5.6.2 Dewatering Operations ............................................................................................. 132 5.6.3 Paving and Milling Operations ................................................................................. 134 5.6.4 Temporary Stream Crossing ..................................................................................... 138 5.6.5 Clear Water Diversion .............................................................................................. 142 5.6.6 Vehicle and Equipment Cleaning ............................................................................. 146 ADOT Erosion and Pollution Control Manual For Highway Design and Construction iv 5.6.7 Vehicle and Equipment Fueling ................................................................................ 148 5.6.8 Vehicle and Equipment Maintenance ....................................................................... 150 5.7 WASTE MANAGEMENT AND MATERIALS POLLUTION CONTROL BEST MANAGEMENT PRACTICES ............................................................................................................. 153 5.7.1 Material Delivery and Storage .................................................................................. 154 5.7.2 Material Use ............................................................................................................. 158 5.7.3 Stockpile Management ............................................................................................. 160 5.7.4 Spill Prevention and Control .................................................................................... 162 5.7.5 Solid Waste Management ......................................................................................... 164 5.7.6 Hazardous Waste Management ................................................................................. 166 5.7.7 Contaminated Soil Management .............................................................................. 170 5.7.8 Concrete Waste Management ................................................................................... 174 5.7.9 Liquid Waste Management ....................................................................................... 178 APPENDIX A PERMITTING FORMS AND CHECKLISTS ................................................. A-1 A.1 A.2 A.3 A.4 A.5 A.6 A.7 SWPPP Checklist ............................................................................................................ 1 Notice of Intent (NOI) Form ........................................................................................... 1 ADOT Standard Sheet (non-tribal lands) ........................................................................ 1 ADOT Standard Sheet (tribal lands) ............................................................................... 1 ADOT AZPDES Inspection Checklist ............................................................................ 1 Methods for Determining Final Stabilization ................................................................. 1 Notice of Termination (NOT) Form ............................................................................... 1 APPENDIX B .................................................................................................... B-1 ABBREVIATIONS, ACRONYMS AND DEFINITION OF TERMS ..................... .............................................................................................................. B-1 TO B-6 APPENDIX C ................................................................................................... C-1 REFERENCES AND RESOURCES.................................................... C-1 TO C-3 ADOT Erosion and Pollution Control Manual For Highway Design and Construction v 1 INTRODUCTION Highway construction has been identified as a primary source of soil erosion and sediment loss. Construction of highways typically disturbs large areas of natural vegetative cover that can result in an accelerated rate of soil erosion. In contrast to highways of the past where the roadways were narrow and profiles followed the contour of the land, contemporary highways have wider cross sections and flatter profiles, which results in large areas of land disturbance, high fills and deep cuts (Figures 1.1 and 1.2). Consequently, highway design and construction requires careful consideration for erosion and sediment control. Erosion and sedimentation from construction sites can have environmental and economic impacts. Environmentally, some of the more common impacts of excessive erosion include: Turbidity, which reduces in-stream photosynthesis and increased water temperatures, leading to reduced food supply and aquatic habitat; Introduction of soil nutrients into waters that cause algal blooms, which reduces water clarity and depletes oxygen; Sedimentation of stream bottoms that blankets fauna and destroys spawning areas; and Removal of top soil that leaves hard, rocky and infertile soil, which is difficult to revegetate. Figure 1.1 Today's highways have wide cross sections that result in large areas of land disturbance These environmental impacts result in damage to aquatic habitat that is difficult to quantify in terms of costs. However, the economic impacts go beyond the cost of damage to natural resources. For example: excessive accumulation of sediment in streams and reservoirs can require dredging at very high costs; replacement and repair of eroded soil can be very expensive; and sediment removal from roadways, channels and culverts can produce additional maintenance costs and cause flood damage (Figure 1.3). ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1-1 1. Introduction Excessive sedimentation can also disturb the physical stability of ephemeral channels, resulting in accelerated rates of erosion and sediment deposition within the channels. Increased erosion and deposition can result in damage to native vegetation and subsequently to local wildlife populations for which ephemeral stream channels are important habitats and movement corridors. Increased channel erosion and sedimentation can also lead to accelerated delivery of sediment downstream to intermittent and perennial stream channels, thereby damaging those environments as well. The Arizona Department of Transportation (ADOT) has adopted this manual to assist in developing erosion and pollution control during both design and construction of roadways. Figure 1.2 (Above) Rill erosion on cut slope Figure 1.3 (Below) Sedimentation at storm drain There are three main goals: Reduce erosion potential. Reduce off-site sedimentation. Prevent contamination by construction materials. These goals are achieved by means of both permanent and temporary storm water Best Management Practices (BMPs). 1-2 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1. Introduction Figure 1.4 When properly designed, today's highways carefully fit into the physical and visual landscape 1.1 PURPOSE OF MANUAL The overall purpose of this manual is three-fold: To outline ADOT's procedures for complying with water quality regulations and permits. To provide a "tool box" of available BMP's. To provide guidance for the selection of BMPs on ADOT construction projects. 1.2 WATER QUALITY REGULATIONS AND PERMITS All ADOT construction projects must comply with federal, state and local water quality regulation and permit requirements. Attention must be given to these regulations and permit requirements through-out the planning, design and construction of a project to insure that the quality of the waters of the U.S. is not compromised. The following is a general overview of the pertinent regulations and permitting requirements. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1-3 1. Introduction 1.2.1 Arizona Department of Environmental Quality's (ADEQ's) Arizona Pollution Discharge Elimination System (AZPDES) Storm Water Permit Requirements. On Dec. 5, 2002, Arizona became one of 45 states with authorization from Environmental Protection Agency (EPA) to operate the National Pollutant Discharge Elimination System (NPDES) Permit Program (Section 402 of the Clean Water Act) (CWA) at the state level. Under the AZPDES Permit Program, all facilities that discharge pollutants from any point source into waters of the U.S. are required to seek coverage under an AZPDES permit. Pollutants can enter waters of the U.S. from various sources including agricultural, domestic, and industrial. For regulatory purposes, these sources are generally categorized as either point source or non-point sources. For similar types of construction activities, the ADEQ has issued a Construction General Permit (CGP), Arizona Construction General Permit (AZCGP) No. AZG2003-001, which is available to provide storm water permit coverage to all construction projects in the State of Arizona (except on Tribal Trust Lands where the construction general permit is issued by the EPA, termed the Federal Construction General Permit or FCGP in this document). In order to comply with the conditions of either the AZCGP or the FCGP, the operator is required to file a Notice of Intent (NOI) with ADEQ or EPA if construction and construction-related activities, including all clearing, grading, excavation, and stockpiling activities, will result in the disturbance of equal to or greater than one acre. ADEQ or EPA approves the specific project use of the general permit for storm water discharges by accepting and approving the NOI. If ADEQ or EPA denies NOI approval, the operator may have to pursue an individual storm water discharge permit for the project. The AZCGP specifies allowable storm water discharges (Part I.C) from construction sites and requires the operator to meet water quality standards through implementation of temporary and permanent BMPs and other measures. Compliance with the requirements of the AZCGP constitutes compliance with the National Pollution Discharge Elimination System permit. In order to obtain coverage, construction contractors under contract to ADOT and ADOT representatives shall: Comply with all terms and conditions of the AZCGP or FCGP. Prepare and implement a site specific Storm Water Pollution Prevention Plan (SWPPP) which meets the minimum requirements of Part IV of the AZCGP. Submit an NOI to ADEQ after the contract has been awarded and before any construction activity begins (the NOI is submitted to the EPA if the project is located on Tribal Trust Lands). These requirements are described under Part II.B and Part III of the AZCGP. 1-4 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1. Introduction Submit a Notice of Termination (NOT) to ADEQ when construction is complete, all permanent erosion and sedimentation controls are in place, and final stabilization has been achieved to meet the requirements described in Part II.C of the AZCGP. The NOI is submitted to the EPA if the project is located on Tribal Trust Lands. Chapters 3 and 4 of this manual provide instructions for preparing a SWPPP and completing the NOI and NOT forms for ADOT projects. 1.2.2 Federal Highway Administration Erosion Control Guidelines Section 1057 of the Intermodel Transportation Efficiency Act of 1991 (ISTEA) requires the Federal Highway Administration (FHWA) to develop erosion and sediment control guidelines for States to follow when building highways using Federal funds. FHWA has formally adopted the American Association of State Highway and Transportation Officials (AASHTO) Highway Drainage Guidelines, Volume III (see Reference 1, Appendix c), for this purpose. Each State highway agency is required to comply with the AASHTO Guidelines or to develop and apply their own more stringent guidelines. 1.2.3 Section 404 of the Clean Water Act Section 404 of the CWA regulates the discharge of dredged or fill material within the waters of the U.S. and establishes a program to issue permits. In Arizona, the U.S. Army Corps of Engineers (Corps) administers this program. In addition, the U.S. Fish & Wildlife, the National Marine Fisheries Service and State resources agencies (e.g., ADEQ, Game and Fish Department, Water Resources) have important advisory roles. The phrase "discharge of dredged or fill material" includes all earthwork activities such as clearing, grading, filling, and excavating. The 404 program has considerable impact on the design, construction and maintenance of Arizona's highways. Essentially, any proposed work in washes, rivers, streams, lakes and wetlands requires ADOT's Environmental and Enhancement Group (EEG) to obtain a permit from the Corps. During construction, the Corps evaluates adherence to permit conditions. Typical projects that are affected include the construction and maintenance of culverts, bridges, and stream bank erosion protection. There are two types of 404 permits: nationwide permits and individual permits. Nationwide permits are general permits designed for allowing minor, noncontroversial projects that are similar in nature, and which create minimal impact on the environment. Individual permits are required for projects that do not meet the terms and conditions for a nationwide permit. They require greater scrutiny by the Corps, other regulatory agencies and the public. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1-5 1. Introduction Requirements for nationwide permits in Arizona are found in the Corps Special Public Notice dated April 19, 2002. Some projects may require an individual permit. The Corps should be contacted for determination of permit requirements. U.S. Army Corps of Engineers Regulatory Branch 3636 N. Central Avenue, Suite 900 Phoenix, AZ 85012-1939 (602) 640-5385 FAX (602) 640-2020 The federal Section 404 permit program can be easily confused with the ADEQ, Section 402, AZPDES program. It is important to remember, however, that they are two separate and distinct regulatory programs. The distinction is that a Section 404 permit provides permission to add fill material to the waters of the U.S., whereas an AZPDES permit provides permission to discharge treated storm waters to the waters of the U.S. in compliance with permit limitations, conditions and BMPs. 1.2.4 Section 401 of the Clean Water Act Section 401 of the CWA enables the States to provide certification that the draft 404 permit is in compliance with State law. ADOT Environmental Planning Group obtains 401 Certification during the design process. The purpose of Section 401 is to ensure that the proposed activity meets the State's water quality standards and any other pertinent state-required criteria. In Arizona, ADEQ performs the State Water Quality Certification Review for all areas of the State with the exception of Indian Reservations. For projects within the White Mountain Apache Reservation, the Tribal Environmental Planning Office performs certification reviews. For projects within all other Indian Reservations in Arizona, EPA performs certification reviews. Section 401 certification requirements apply to all activities regulated under Section 404 of the CWA. The certification review evaluates proposed projects for compliance with state water quality standards and consistency with approved water quality planning and management programs. ADEQ may approve or deny certification for any Section 404 Permit based on the anticipated effect on water quality. A Letter of Certification will be issued by ADEQ if the applicant is in compliance with these standards and conditions. In order to obtain a letter of certification from ADEQ, construction contractors under contract to ADOT and ADOT representatives shall contact ADEQ Water Permits Division. 1-6 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1. Introduction 1.2.5 Additional Federal Land Requirements There are several agencies within the U.S. government that manage public lands and may have their own erosion and pollution control requirements. These agencies include the BLM, the BIA, the U.S. Forest Service, the National Parks Service and the U.S. Fish and Wildlife Service. Each affected agency shall be included in the planning and design process when roadway plans are prepared within their jurisdictions. Doing so will ensure that their requirements are incorporated into the plans. Contact Information: Bureau of Land Management � http://www.blm.gov/nhp/ Bureau of Indian Affairs - www.doi.gov/bureau-indian-affairs.html The U.S. Department of Agriculture Forest Service � www.fs.fed.us/ Southwestern Region USDA Forest Service 333Broadway SE Albuquerque, NM 87102 (505) 842-3192 The National Parks Service � www.nps.gov/ Pacific West Region, Regional Director National Park Service One Jackson Center 1111 Jackson Street Suite 700 Oakland, CA 94607 (510) 817-1300 U.S. Fish and Wildlife Service � www.fws.gov/ Southwest Region 2 500 Gold Ave. SW Albuquerque, NM 87102 (505) 248-6635 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1-7 1. Introduction 1.2.6 State and Local Government and Agency Requirements The Arizona State Land Department does not have a specific policy on erosion control for construction projects but rather reviews projects on a case-by-case basis. For projects that are located on State Trust Land contact: Arizona State Land Department Right-of-Way Section 1616 W. Adams St. Phoenix, AZ 85007 (602) 542-4098 Other environmental issues such as archaeological and/or historic sites may be identified during project planning and design that affect design and construction activities. These issues may affect the contractor's proposed activities outside of the approved right-of-way. Projects may also be located within the jurisdictions of local governments. These may include Municipal Separate Storm Sewer Systems (MS4) and County Flood Control Districts. Each affected agency shall be included in the planning and design process when roadway plans are prepared within their jurisdictions. This will ensure that their requirements are incorporated into the plans. Contact Information: Local Government Units Phone Listings in Government Pages Arizona Council of Governments Website http://www.mag.maricopa.gov/archive/AZ-COGs/index.html Municipal Separate Storm Sewer Systems Arizona Department of Environmental Quality Listings http://www.adeq.state.az.us/environ/water/permits/stormwater.html EPA Region 9: Water Programs Website http://www.epa.gov/region09/water/npdes/stormwater.html County Flood Control Districts Phone Listings County Government Pages Arizona Association of Counties Website http://www.azcounties.org/home/index.cfm 1-8 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1. Introduction 1.3 BEST MANAGEMENT PRACTICE (BMP) SELECTION AND DESIGN As used in this document, the term BMP refers to operational (non-structural) activities or physical controls (structural) that prevent or reduce the discharge of pollutants and minimize potential impacts upon receiving waters. Proper BMP design, selection and installation are essential to achieve the goals of this manual. BMP selection begins during the design phase but must be continued by the contractor and ADOT throughout the life of the project. The most effective way to reduce erosion and offsite sedimentation and to prevent the contamination of storm water is to select and install BMPs that best fit the specific conditions encountered. This manual provides the following: Chapter 2: Design guidance for incorporating storm water quality controls in projects during the planning and design phases. Chapter 3: Instructions to the contractor for obtaining a Construction General Permit. Chapter 4: Instructions to the contractor for preparing a SWPPP, a necessary requirement of the General Permit. Chapter 5: Descriptions of both temporary and permanent BMPs for consideration by ADOT and the contractor during design and construction of ADOT projects. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 1-9 2 PROJECT PLANNING AND DESIGN GUIDE 2.1 OVERVIEW As used in this document, the term BMP refers to operational activities or physical controls that reduce the discharge of pollutants and minimize potential impacts upon receiving waters. There are two categories of BMPs within ADOT: Permanent Pollution Prevention BMPs and Temporary Pollution Prevention BMPs. Permanent Pollution Prevention BMPs are permanent measures to improve storm water quality both during and after construction of the project. They include: 1. The minimization of impermeable surfaces; 2. The re-establishment of vegetation to disturbed soils (Figure 2.1); 3. The evaluation of increased runoff flows; 4. The preservation of existing vegetation; 5. The design of concentrated flow structures; and 6. The design of measures to protect disturbed slopes. Figure 2.1 Revegetated cut slope Figure 2.2 Installation of erosion control blanket Temporary Pollution Prevention BMPs are temporary measures to improve storm water quality during the construction process. They include: 1. Temporary soil stabilization and sediment control (Figure 2.2); 2. Non-storm water management; and 3. Waste management. The objective of this chapter is to provide guidelines for the consideration of permanent pollution prevention BMPs during the ADOT planning and design processes. 2-10 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2. Project Planning and Design Guide 2.2 PROJECT PLANNING AND DESIGN During the design process, the Landscape Architect and Engineer must endeavor to minimize the impacts to water quality that may be caused by the project. In order to maintain water quality affected by a project, ADOT has established the following objectives: 1. Maximize vegetated surfaces; 2. Stabilize disturbed soils; 3. Prevent downstream erosion. The designer should consider the BMPs described in this chapter in order to achieve these objectives. 2.2.1. Evaluate Increased Runoff Flows The project design may increase the amount of impermeable surface area within the project area, resulting in increased runoff quantities from the project site. The project design may also increase the velocities of existing offsite runoff flows by concentrating those flows into smaller drainage structures. Consequently, large storm events may result in greater peak runoff discharges into existing drainages than those drainages may have historically received. To address these concerns, the designer shall consider the following: Drainage design: Bridges typically affect offsite runoff less significantly than do culverts and may be less visually intrusive; Bio-engineered designs such as live fascines and/ or pole plantings; Modifications to receiving drainages: the drainage may need to be protected by means of vegetation, geotextile mats, rock or riprap; Energy dissipation devices at culvert outlets; Reducing the turbulence and scour at culvert inlets and outlets by smoothing the transition between culvert inlets and outlets and drainages; Incorporating detention facilities into project design in order to reduce peak discharges; and Spread runoff flows across channel outlet structures in order to mimic natural drainage channels. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2-11 2. Project Planning and Design Guide Figure 2.3 Preserving vegetation and limiting land disturbance are major factors in highway erosion prevention 2.2.2 Preservation of Existing Vegetation Existing vegetation provides natural protection against soil erosion and should be preserved wherever possible (Figure 2.3). Mature plants have extensive root structures that help hold soil in place and reduce erosion. Vegetative foliage also helps reduce erosion by absorbing the impact of raindrops that would otherwise fall directly to the ground and erode the soil. Disturbed soils typically erode at much greater rates than do undisturbed soils. T h e r e f o r e , the designer should seek to minimize land disturbance by the following general guidelines: Minimize land disturbance through appropriate design to balance cut and fill and to reduce the length and steepness of the highway slopes and the extent of grading (typically, vegetation will not successfully colonize slopes greater than 2:1, H: V); Areas to be preserved should be delineated prior to the start of soil-disturbing activities. Vegetation that lies within transition areas of cuts or fills and outside of clear zones should be preserved in place; For larger projects, existing vegetation should be preserved for as long as possible where activity will occur later in the construction process; Temporary roads should be located to avoid stands of significant vegetation and to follow existing contours to reduce cutting and filling; and Temporary roads should be located within limits of area to be disturbed by permanent road construction. 2-12 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2. Project Planning and Design Guide Figure 2.4 and Figure 2.5 Swale with check dams 2.2.3 Concentrated Flow Structures 2.2.3.1 Ditches and Dikes These are permanent devices used to intercept and direct surface runoff into a drain and/or into an existing drainage. Because they concentrate storm water runoff, they are highly susceptible to erosion. Therefore, the designer should consider the following: The drainage design should include calculations of peak flows and velocities for all drainage structures and should provide erosion control measures where erodable velocities occur (Table 2.1); To prevent downcutting, riprap should be considered for all ditches and dikes that exceed five percent slope; and Rock check dams reduce runoff velocity and capture sediment (Figures 2.4 and Figure 2.5). ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2-13 2. Project Planning and Design Guide Figure 2.6 Cut fill transition Maximum Permis s ibl e Velocities For: S oil Type or Lining (earth: no vegetation) W ter a W ter C arrying a C lear W ter C arrying Fine a S and and S ilts Gravel F.P.S. Fine sand (noncolloidal) Sandy loam (noncolloidal) Silt loam (noncolloidal) Ordinary firm loam Fine gravel Stiff clay (very Colloidal) Graded, loam to cobbles (noncolloidal) Graded, silt to cobbles (colloidal) Alluvial silts (noncolloidal) Alluvial silts (colloidal) Coarse gravel (noncolloidal) Cobbles and shingles Shales and hard pans 1.5 1.7 2.0 2.5 2.5 3.7 3.7 4.0 2.0 3.7 4.0 5.0 6.0 F.P.S. 2.5 2.5 3.0 3.5 5.0 5.0 5.0 5.5 3.5 5.0 6.0 5.5 6.0 F.P.S. 1.5 2.0 2.0 2.2 3.7 3.0 5.0 5.0 2.0 3.0 6.5 6.5 5.0 Table 2.1. Permissible Velocities for Channels with Erodible Linings, Based on Uniform Flow in Continuously Wet, Aged Channels1 As recommended by Special Committee on Irrigation research, American Society of Civil Engineers, 1926. From: FHWA - Hydraulic velocity by: 0.95 for slightly sinuous; 0.90 for moderately sinuous; and 0.80 for highly sinuous. 1 2-14 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2. Project Planning and Design Guide Figure 2.7 (left) Spillway (with failed temporary embankment curb) Figure 2.8 (right) Culvert protection Ditches and dikes also act as devices to prevent erosion. During the design process, the designer should consider the following: Crown ditches installed at the tops of slopes to divert runoff from adjacent cut slopes. Construction should take place prior to excavation of the slope. The designer should give careful consideration to crown ditch outlets to avoid downstream erosion and minimize ditch maintenance. In addition, since crown ditches can be highly visible to motorists, consideration should be given to ditch layout and existing vegetation. Finally, the designer should keep in mind that all ditches required maintenance; therefore, crown ditch access should be a consideration; Slope ditches: Installed at bottom and mid-slope locations to intercept sheet flow and convey concentrated flows; Embankment curbs: Installed on fill slopes at the edge of the roadway to intercept sheet flow from paved surfaces. Embankment curbs are of special consideration where the roadway is super-elevated, thereby directing all sheet flow to one side of the pavement; and ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2-15 2. Project Planning and Design Guide Cut-to-fill slope transition protection: Installed at the intersection of cut and fill slopes. Cut ditches that discharge at cut-to-fill slope transitions will normally require erosion protection until runoff flows reach an existing stable drainage (Figure 2.6). Figure 2.9 Rock rip rap at culvert 2.2.3.2 Overside Drains Overside drains are pipes, downdrains and spillways used to protect slopes against erosion by collecting surface runoff and conveying it down the slope to a stabilized drainage. The designer should consider their use as follows: Cut slope spillway: Installed where offsite runoff will intercept a cut slope. Because cut slopes typically are highly visible to motorists, consideration should be given to the aesthetic design of these structures; and Fill slopes: Where embankment curbs are installed, openings in the curb are constructed that drain into a spillway or downdrain. Generally, downdrains are used for aesthetic reasons where slopes will be visible from a main roadway (Figure 2.7). 2.2.3.3 Culvert and Channel Outlets Culvert and structural channel outlets are typically areas of high concern for erosion. The designer should consider the following: Careful review of inlet invert elevation: When lower than the existing natural channel, the channel backslope must be protected to avoid headcutting of that slope by runoff; ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2-16 2. Project Planning and Design Guide Flared end section: These are typically installed at the inlets and outlets of pipes and channels to improve the hydraulic operation, retain the embankment near pipe conveyances and help prevent scour (Figure 2.8); Outlet protection/ velocity dissipation devices: In order to prevent scour at the outlet and to reduce runoff flow velocity, rock riprap or some other measure is typically installed. These devices should be constructed during or immediately after construction of the culvert; and Protection at the soil/ drainage structure interface: The interface between fill slope soils and concrete or metal structures is typically prone to erosion. While this interface frequently occurs at drainage structure outlets, it is also possible at the edges of spillways and bridge abutments. The designer should consider the use of rock or other protective measure to prevent erosion in this area (Figure 2.9). 2.2.4 Slope Protection Surface protection consists of permanent design measures that are used alone or in combination to minimize erosion from disturbed surfaces. Vegetated surfaces may offer several advantages to paved surfaces including lower runoff volumes, slower runoff velocities, increased times of concentration and lower cost. However, where site-specific conditions would prevent adequate establishment and maintenance of a vegetative cover, hard surfacing should be considered. 2.2.4.1 Vegetated Surfaces A vegetated surface is a permanent vegetative cover on areas that have been disturbed. The purpose of the vegetated surface is to prevent erosion and remove pollutants (including sediment) in storm water runoff. Vegetated surfaces should be established on areas of disturbed soil after construction related activities in that area are completed and after the slope has been prepared. Vegetated surfaces should only be considered for areas that can support the selected vegetation long-term. Typically, responsibility for treatment of vegetated slopes rests with the project Landscape Architect as follows: Project site shall be evaluated for soil types and conditions; topography; local climate and season; existing native vegetation types and species; Surfaces to be vegetated shall be designed to maximize rainfall infiltration and minimize concentrated flow volumes and speeds. Slopes shall be considered for roughening, terracing, and rounding; and Existing project site topsoil and vegetation shall be considered for salvage during clearing and grubbing operations. Use salvaged materials as part of surface preparation prior to seeding. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 2-17 2.2.4.2 Hard Surfaces Hard surfaces consist of placing concrete, rock or rock and mortar. Typically, these measures are considered where vegetation will not provide adequate erosion control and/or where vegetation will be difficult to maintain. The designer should to consider the downstream effects of increased runoff volumes and velocities from hard surfaces. Typical applications include bank protection and bridge abutments. 2.2.4.3 Erosion and Sediment Control Plans and Details. As part of the project design process, the designer should develop plans and details which direct the contractor to the proper locations, installation and maintenance of BMPs. The intent of these plans is to provide general direction and specific BMP expectations to the contractor. They will not be considered a complete SWPPP and shall not replace the contractor's SWPPP, since the project plans and details are prepared assuming standard construction practices and may not reflect the contractor's actual methods of construction, access requirements or project phasing. The contractor shall use the project plans as a guide in developing his own SWPPP. Figure 2.10 Installation of sediment wattles 2-18 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3 INSTRUCTIONS FOR OBTAINING ARIZONA OR FEDERAL CONSTRUCTION GENERAL PERMIT AUTHORIZATION FOR ADOT CONSTRUCTION PROJECTS The following sections describe the steps that ADOT and the general contractor will follow to comply with the ADEQ's AZCGP requirements (federal CGP instructions are described at the end of this chapter). Within each section a short summary of responsibilities for the individuals involved in the construction process is explained. It is ADOT's intent to share responsibilities on the job site with the contractor. It shall not be the general contractor's nor ADOT's sole responsibility to comply with AZCGP requirements. Instead, it is a shared obligation between ADOT and the general contractor and subcontractors to protect the environment. S tep Step 1 Action Prepare a Storm Water Pollution Prevention Plan (SWPPP). Certify the SWPPP AZC GP R eference Part IV Information & forms Chapter 4 Appendix A, Contract Documents ADOT Stored Specification 104SWDEQ ADOT Standard Sheet-Appendix A "AZPDES SWPPP Index" Appendix A www.adeq.state.az.us Project Specifications Project Specifications Step 2 Part IV.C.1, Part IV.J.1, Part VII.K Part III Step 3 Submit a Notice of Intent (NOI) Step 4 Retain the NOI and SWPPP at the job site Implement the SWPPP Part IV.J. Part IV.D Step 5 Inspect the BMP's regularly and after Part IV.H, each storm event Adjust the SWPPP to fit site conditions Maintain an Updated SWPPP Maintain the BMPs Part IV.H.7 Part IV.I Part IV.E.1 -3 Maintenance, record keeping and sitemonitoring forms - Appendix A Project Specifications ADOT Inspection Form Appendix A Project Specifications Project Specifications Project Specifications BMP descriptions-Appendices A & B Final Stabilization Methods Appendix A Project Specifications Appendix A www.adeq.state.az.us Project Specifications Project Specifications Step 6 Step 7 Step 8 Step 9 Step 10 Evaluate job site to determine if Final Part IX - definition of Stabilization is achieved final stabilization Submit Notice of Termination (NOT) Part II.C Step 11 Step 12 Retain Records after project is complete for 3 years. Part VI Table 3.1 Steps for obtaining Arizona Construction General Permit Authorization ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-19 3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.1 STEP 1: PREPARE A STORM WATER POLLUTION PREVENTION PLAN (SWPPP) A complete SWPPP shall be developed by an Erosion Control Coordinator who is designated by the contractor in accordance with the project specifications. Instructions for completing a SWPPP are included in Chapter 4. Two copies of the draft SWPPP shall be submitted to the Engineer at the preconstruction conference if possible, but not later than 14 calendar days from the Department's approval of the contractor's Erosion Control Coordinator. Responsibilities: ADOT: Provide supporting documents required to complete the SWPPP. Review the credentials of the Erosion Control Coordinator selected by the contractor. Review the draft SWPPP submitted by the contractor. The Contractor: Designate an Erosion Control Coordinator. The Erosion Control Coordinator shall prepare the SWPPP. 3.1.1 Project Document BMPs As described in Section 2.2.4.3, during the project design process ADOT will prepare storm water pollution prevention plans (entitled "Erosion and Sediment Control Plans"), details (entitled "Erosion and Sediment Control Details") and specifications (in Section 810 of the Special Provisions) using BMPs from this manual and BMPs developed for unique conditions particular to individual projects. The project documents will provide direction and specific expectations to the contractor regarding storm water pollution prevention. However, these documents shall not be considered a complete SWPPP and shall not replace the contractor's SWPPP, since the project documents are prepared assuming standard construction practices and may not reflect the contractor's actual methods of construction, access requirements or project phasing. Instead, the contractor shall use the project documents as a guide in developing his own SWPPP. 3.2 STEP 2: CERTIFY THE SWPPP ADOT, the contractor and any subcontractors that are responsible for constructing the pollution controls must certify the SWPPP. In the case of ADOT local government projects involving federal aide, the appropriate municipality shall also certify the SWPPP. Refer to the AZCGP Part IV.C.1, Part IV.J.1, and Part VII.K for specific instructions. The certifications shall occur after award of the contract and before construction begins. 3-20 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3. Instructions for Obtaining a Construction General Permit for ADOT Projects As described earlier, it is the obligation of all personnel involved in the construction process to protect the environment. The certification requirement shall reinforce the fact that it takes a team effort to properly control storm water pollution and that the responsibility is equally shared between ADOT and its contractors and subcontractors. The following certification is required by ADEQ and is included on ADOT's "AZPDES SWPPP Index" Sheet (Appendix A). Responsibilities: ADOT: The Engineer will certify the SWPPP. I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. The Contractor: The Contractor, the Erosion Control Coordinator and any Subcontractors who are involved in implementing measures identified in the SWPPP must sign the certification. 3.3 STEP 3: SUBMIT NOTICE OF INTENT (NOI) A complete and accurate NOI form must be prepared and signed by the operator(s) to receive coverage under the AZCGP. The NOI form serves as a promise that the operator(s) will comply with the AZCGP conditions. An operator(s) is any person associated with the project that has control over the construction plans or specifications (the ADOT Engineer) or day-to-day operational control of the site (the Contractor, the Erosion Control Coordinator, and any Subcontractor directly associated with installation or maintenance of BMPs). Refer to Part IX of the AZCGP for a complete definition of operator. The NOI must be mailed to ADEQ at least 2 business days before any construction activities occur at the site (AZCGP Part III.C.1). If the project is located within or has the potential to discharge to an MS4, a copy of the NOI must also be submitted to the MS4 (AZCGP Part III.F). A list of MS4 municipalities in Arizona is located on the ADEQ website (www.adeq.state.az.us). Also, contractors operating under an approved local sediment and erosion control plan, grading plan, or storm water management plan shall submit a signed copy of the NOI to the local authority upon their request. If the project site is ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-21 3. Instructions for Obtaining a Construction General Permit for ADOT Projects located within 1/4 mile of unique or impaired waters, the NOI must be submitted at least 32 business days before any construction activities occur at the site (AZCGP Part II.B.1). A SWPPP that satisfies the conditions of the AZCGP must be completed and certified prior to submitting the NOI to ADEQ. It is not necessary for the SWPPP to be included with the NOI, but the SWPPP must always be available for ADEQ review. The SWPPP must be submitted to ADEQ with the NOI if the construction site is located within 1/4 mile of a unique or impaired water (AZCGP Part II.B.1). The NOI form and detailed instructions for completing the form are available at the ADEQ website (www.adeq.state.az.us) or by calling either 602-771-4665 or 602-771-4449. Submit NOI form by certified mail or hand delivery to: Arizona Department of Environmental Quality Water Permits Section/Storm Water NOI (5415B-3) 1110 W. Washington Street Phoenix, AZ 85007 Forms can be faxed to 602-771-4674. The agency now offers a Web-based service to assist individuals in applying for construction storm water discharge permits (Smart NOI). Access the website as described above. Responsibilities: ADOT: Because of its control over the project specifications, ADOT is required to submit the NOI. Following approval by ADOT and completion of the Contractor-prepared SWPPP, the Engineer shall prepare, sign, and mail the NOI for ADOT. The Contractor: Because he has day-to-day control over the job site, the Contractor also is required to submit the NOI. The Contractor shall prepare the NOI after certification of the SWPPP and mail the signed forms at least 48 hours before any construction begins. 3-22 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.4 STEP 4: RETAIN DOCUMENTS AT THE JOB SITE The following documents must be kept with the SWPPP and retained on the job site, or a location easily accessible during normal business hours, throughout the construction process: Document Copy of the AZPDES AZCGP (AZG2003-001) NOI (as completed by the contractor and ADOT) AZPDES authorization number for the project. Other agreements with any state, local or federal agencies that affect the provisions or implementation of the SWPPP. AZC GP R eference S ource www.adeq.state.az.us Part IV.J Part IV.J.2 Part IV.J.3 www.adeq.state.az.us Provided by ADEQ after NOI is approved. ADOT environmental clearance documents Responsibilities: ADOT: The Engineer shall keep copies of the above-mentioned documents at the construction office. The Contractor: The contractor shall post a sign or other notice near the main entrance of the construction site with specific information requested in Part IV.J.2 of the AZCGP. If the contractor maintains a construction office at or near the site, the SWPPP with all the above-mentioned attachments shall be kept at the office. If there is no construction office, the contractor's superintendent and ADOT's inspector shall keep copies in their vehicles. 3.5 STEP 5: IMPLEMENT THE SWPPP After the NOI is accepted and an authorization number received, construction may begin that will require implementation of the SWPPP (Quick Start projects require special coordination with the Engineer). The pollution controls (i.e., the BMPs) shall be constructed in accordance with the SWPPP. The SWPPP is intended to be a dynamic plan that shall be revised as a result of unanticipated or changing conditions during construction. Making changes to the plan where it is not effective is a requirement of the AZCGP. Any changes to the plan shall be noted and dated on the plan. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-23 3. Instructions for Obtaining a Construction General Permit for ADOT Projects Responsibilities: In order to effectively implement the SWPPP, ADOT and the contractor shall monitor and record weeklyextended weather forecasts. The contractor and the Engineer shall discuss these forecasts at regularly scheduled weekly progress meetings. In the event that extended forecasts report a high probability for precipitation in the project area, the contractor shall ensure that all BMPs in the SWPPP have been properly installed and maintained. He shall also install additional measures in areas determined to be susceptible to erosion as directed by the Engineer. Stabilization measures shall be installed within 14 calendar days in portions of the site where construction activities have temporarily or permanently ceased. Exceptions can be found in the AZCGP Part IV.D.4. The Engineer and the contractor are jointly responsible for implementing the SWPPP and maintaining dated records of : Major grading activities. Areas where construction activities have temporarily or permanently stopped. Installation of stabilization measures (BMPs). Delays and reasons for delays of installation of stabilization measures. These records shall be included in the SWPPP. A sample form for record keeping is included in Appendix A. 3.6 STEP 6: INSPECT THE BMPS REGULARLY Regular site inspections are required as part of the AZCGP (Part IV.H) to ensure that BMPs are functional and that the SWPPP is properly maintained. The AZCGP requires regular inspections. In areas of the state that receive greater than 20 inches mean annual rainfall, the inspection requirement is every 7 calendar days or once every 14 calendar days and within 24 hours after a rainfall event of 1/2 inch or greater. In areas of the state that receive less than 20 inches mean annual rainfall and construction occurs during the seasonal dry period, inspections are required monthly, anytime rain is predicted and within 24 hours following a rainfall event of 1/2 inch or greater. Refer to the following map (Figure 3.1) to determine the locations in Arizona where the mean annual rainfall is less than or greater than 20 inches. The reduced inspection frequency requirement also applies to sites where runoff is unlikely due to winter conditions. 3-24 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3. Instructions for Obtaining a Construction General Permit for ADOT Projects Inspections must be preformed by qualified personnel as described in Part IV.H.3 of the AZCGP and as specified in the project specifications. Inspections must include all areas of the site disturbed by construction activity, staging areas and areas used for storage of materials that are exposed to precipitation. Refer to AZCGP Part IV.H.4 for a complete scope of inspections. ADOT has developed an AZPDES inspection checklist to be used on ADOT construction projects (Appendix A). The completed ADOT checklist and any additional sheets necessary to record the results of the inspection shall serve as the Compliance Evaluation Report (Part IV.H.5). The Report and the record of any follow-up actions taken shall be retained as part of the SWPPP. Responsibilities: ADOT: Responsible for inspections of BMPs and approval of any follow-up actions deemed necessary following the inspections. The Contractor: Responsible for inspections, inspection reports and installation and maintenance of all BMPs. Responsible for required follow-up actions within time limits described in project specifications. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-25 3. Instructions for Obtaining a Construction General Permit for ADOT Projects Figure 3.2 Arizona Climate Map ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-26 3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.7 STEP 7: ADJUST THE SWPPP TO FIT SITE CONDITIONS The operator shall implement follow-up actions based on results of the inspection process within seven calendar days following the inspection, or as required by the project specifications. Where adjustments to the SWPPP are deemed necessary, implementation must be completed before the next anticipated storm event or as soon as practical (AZCGP Part IV.H.7). Responsibilities: ADOT: Responsible for the approval of any changes or additions to the SWPPP based on specific site conditions. The Contractor: Responsible for the installation and adjustment of BMPs to fit specific site conditions deemed necessary as a result of inspections. The contractor is also responsible for recording these actions on the SWPPP. 3.8 STEP 8: MAINTAIN AN UPDATED SWPPP It is imperative that the SWPPP remain current with the changes and adjustments made in the field. Failure to update the SWPPP is considered a violation of AZCGP conditions and grounds for issuance of a failure notice. The SWPPP shall be updated within 15 calendar days if changes in design, scheduling or maintenance activities have a significant effect on the discharge of pollutants or it is determined that discharges from the construction site are causing or contributing to water quality exceedances (Refer to AZCGP Part IV.I). Responsibilities: ADOT: The Engineer must retain copies of updated SWPPP in his vehicle. The Contractor: Must maintain an updated SWPPP. 3.9 STEP 9: MAINTAIN THE BMPS All erosion and sediment control measures and other protective measures identified in the SWPPP must be maintained in effective operational condition (Refer to AZCGP Part IV.E.1-3). ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-27 3. Instructions for Obtaining a Construction General Permit for ADOT Projects Responsibilities: ADOT: Responsible for inspections and approval of maintenance activities. The Contractor: Responsible for the maintenance of all erosion and sediment control measures. 3.10 STEP 10: EVALUATE JOB SITE TO DETERMINE FINAL STABILIZATION Final Stabilization shall be defined as the completion of all soil-disturbing activities and the two following criteria have been met: A uniform (i.e., evenly distributed, without large bare areas) perennial vegetative cover with a density equivalent to 70% of the native background vegetative cover has been established on all unpaved areas and areas not covered by permanent structures. Where perennial vegetation is not yet fully established, temporary erosion control devices are properly installed and fully operational. Permanent erosion control measures (e.g., riprap, gabions, or geotextiles) have been employed and are fully operational. Refer to Appendix A for methods for determining final stabilization for native seeded/unpaved areas. Responsibilities: ADOT: Determine final acceptance in accordance with the project specifications. The Contractor: Initiate inspections to determine if final stabilization has been achieved. 3.11 STEP 11: SUBMIT NOTICE OF TERMINATION (NOT) A complete and accurate NOT must be submitted to ADEQ after it has been determined that the project has met the submittal criteria as described in 3.10 above. The NOT form is available at the ADEQ website www.adeq.az.us or by calling 602-771-4665 or 4449. 3-28 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3. Instructions for Obtaining a Construction General Permit for ADOT Projects Submit form by certified mail or hand delivery to: Arizona Department of Environmental Quality Storm Water Program - Water Permits Section/NOT (5415B-3) 1110 W. Washington Street, Phoenix, AZ 85007 Responsibilities: ADOT: The Engineer is responsible for filling out, signing and submitting the NOT form for ADOT. The Contractor: The Contractor is responsible for submitting his own NOT form to ADEQ and providing one copy to the Engineer. In the case of an urban highway project where the landscape contract lags behind the paving project, the following rules apply for submitting the NOT: If the bare ground is temporarily seeded and mulched as part of the paving project, ADOT and the contractor shall submit NOTs when the contract is complete. At the start of the subsequent landscape contract, both ADOT and the landscape contractor shall submit NOIs to obtain a new permit to cover the landscaping activities. If temporary seeding and mulching are not part of the paving project, ADOT cannot submit a NOT until after the completion of the landscaping project. Therefore, ADOT shall maintain temporary erosion and sediment controls in the area. ADOT shall also perform regular inspections (in accordance with the AZCGP) during the interim period after the paving project is complete and before the landscape contract begins. It should be noted that in this latter case, the paving contractor will submit a NOT at the end of the paving contract and the landscape contractor will submit a NOI before beginning subsequent work. In the interim, ADOT will have sole responsibility for the project. 3.12 STEP 12: RETENTION OF RECORDS ADOT and the Contractor shall retain copies of SWPPPs and all documentation required by this permit, including records of all data used to complete the NOI to be covered by this permit, for at least three years from the date of final stabilization of the site (AZCGP Part VI). ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-29 3. Instructions for Obtaining a Construction General Permit for ADOT Projects 3.13 SPECIAL CONDITIONS, REQUIREMENTS AND EXCEPTIONS C ondition, R equirement or E xception Permit Requirements for Tribal Trust Lands Action Permit must be obtained through the EPA Location of forms and further information EPA website: www.epa.gov http://cfpub.epa.gov/npdes/index.cfm ADOT Stored Specification 104SWEPA Permit Requirements for discharge to unique or impaired waters Follow instructions outlined in AZCGP and submit NOI, SWPPP and Monitoring Program 32 business days before construction activity will begin AZCGP Part II.B.1 www.adeq.state.az.us This chapter - for AZCGP instructions Chapter 4 - for SWPPP preparation Permit Requirements for Batch Plants, Borrow Pits and Material Pits located outside the right-of-way. Waivers for Small Construction Activities Obtain permit coverage under Multi- www.adeq.state.az.us Sector General permit for AZCGP Part I.C.1.c for definition of construction activities not directly allowable discharges. related to a construction site. Determine if project equal to or greater than 1 acre but less than 5 acres is exempt from permit requirements AZCGP Part I.E and Part III.B Table 3.3 Special Conditions, Requirements and Exceptions 3.13.1 Permit Requirements on Tribal Trust Lands If the project is located entirely on Tribal Trust Lands, permit coverage shall be obtained through the EPA (http://cfpub.epa.gov/npdes/index.cfm). Follow these steps (described in detail on the EPA website) and refer to the ADOT Stored Specification 104SWEPA to obtain coverage: Step 1: Read the FCGP and fact sheet. Step 2: Determine if project is eligible for coverage under the FCGP. Step 3: Develop and implement SWPPP (follow instructions in Chapter 4). Step 4: Complete and submit a NOI. 3-30 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3. Instructions for Obtaining a Construction General Permit for ADOT Projects Forms can be submitted by mail to: Storm Water Notice Processing Center Mail Code 4203M U.S. EPA 1200 Pennsylvania Avenue, NW Washington, DC 20460 Electronic NOI forms are available from the following website: http://cfpub.epa.gov/npdes/stormwater/enoi.cfm If the project site is located on the White Mountain Apache Reservation, the NOI shall be sent to: Tribal Environmental Planning Office P.O. Box 2109 Whiteriver, AZ 85941 3.13.2 Permit requirements for projects located within 1/4 mile of Impaired or Unique Waters. If the project site is located within � mile of unique (R18-11-112) or impaired (Section 303(d) of the CWA) waters, the NOI and the SWPPP must be submitted to ADEQ at least 32 business days before any construction activities occur at the site (AZCGP Part II.B.1). This extra time allows ADEQ to review the SWPPP to determine whether selected BMPs are sufficiently protective of water quality. The SWPPP must include a proposal for monitoring to determine if BMPs and controls are effective (AZCGP Part I.D.5.a). 3.13.3 Permit requirements for Batch Plants, Borrow Pits and Material Pits Discharges from support activities such as concrete or asphalt batch plants, equipment staging yards, material storage areas, screening and crushing plants, excavated material disposal areas and borrow areas are covered under the AZCGP if the conditions of the permit are followed (AZCGP Part I.C.1). The contractor must obtain coverage under a separate Multi-Sector General Permit (MSGP) for activities that do not fall under the allowable discharges for an AZCGP. 3.13.4 Waivers for Small Construction Activities Small Construction Activities, equal to or greater than 1 acre and less than 5 acres may be exempt from Arizona or Federal Construction General Permits if: The project's rainfall erosivity factor calculation is less than 5 during the entire period of construction activity (AZCGP Part I.E.1) or, When an EPA-approved "total maximum daily load" indicates that receiving waters will not be impacted by discharges from the project (AZCGP Part I.E.2). ADOT Erosion and Pollution Control Manual For Highway Design and Construction 3-31 4 STORM WATER POLLUTION PREVENTION PLANS (SWPPP) Storm Water Pollution Prevention Plans (SWPPPs) are developed to describe operational activities and physical controls (BMPs) that will be used to prevent the discharge of pollutants into the waters of the United States. SWPPPs are site specific and, for ADOT construction projects, the contractor develops them as a first step in obtaining a CGP. A useful construction SWPPP checklist can be downloaded from the ADEQ website (www.adeq.state.az.us) and is included in Appendix A. The follow steps have www.adeq.state.az.us been developed to provide direction and resources to facilitate the completion of the SWPPP. S tep Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Action Identify all operators for the Project Describe the Site and Prepare a Schedule of Construction Activities Select Controls to Reduce Pollutants Prepare a Plan for Maintenance of BMPs Collect Permit Related Documents Comply with Applicable Federal, State and Local Programs Develop a Site Specific Inspection Plan AZC GP R eference Part IV.C Part IV.C Part IV.D Part IV.E Part IV.F Part IV.G Part IV.H Information & forms ADOT Standard Sheet Project Specifications Chapters 2 & 5 Appendix A Chapter 1Design Documents ADOT AZPDES Inspection Checklist 4.1 STEP 1: IDENTIFY ALL OPERATORS FOR THE PROJECT An operator(s) is any person associated with the project who has control over the construction plans or specifications (ADOT) or day-to-day operational control of the site (the Contractor, the Erosion Control Coordinator, and any Subcontractor directly associated with installation or maintenance of BMPs). Operators certify the SWPPP (Chapter 3, Step 2) and are identified on the Standard "AZPDES SWPPP Index" Sheet in the erosion and sediment control plans developed by ADOT. 4-32 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 4. Storm Water Pollution Prevention Plans (SWPP) 4.2 STEP 2: DESCRIBE THE SITE AND PREPARE A SCHEDULE OF CONSTRUCTION ACTIVITIES Much of the information needed to complete this portion of the SWPPP is included in the contract documents or in reports that are generated as part of the design process. These reports include the soils/geotechnical report, the project drainage report, and the environmental clearance documents and are available from ADOT. For larger projects, the project site may be divided into sub-areas based on the maximum allowable exposed area as specified in the project specifications. A schedule of construction activity shall be developed for each sub-area. 4.3 STEP 3: SELECT BMPS TO REDUCE POLLUTANTS To comply with Part IV.D of the AZCGP, the SWPPP must describe all BMPs that will be implemented as part of the construction project to control pollutants in storm water discharges. The SWPPP must clearly describe appropriate control measures to be used in each sub-area. Refer to the BMP descriptions in Chapter 5 when selecting appropriate permanent and temporary controls. As discussed in Section 3.1.1, ADOT will prepare Erosion and Sediment Control plans and details as part of the construction documents. These will provide direction and specific BMP expectations to the contractor. However, the project documents shall not be considered a complete SWPPP and shall not replace the contractor's SWPPP, since the project plans and details are prepared assuming standard construction practices and may not reflect the contractor's actual methods of construction, access requirements or project phasing. The contractor shall use the project plans as a guide in developing his own SWPPP. The SWPPP must also describe the "Good Housekeeping" procedures and practices as specified in the project specifications. These include: An inventory of chemicals and materials needed for construction. A spill prevention and clean-up plan; A description of storage, use and disposal of chemical and construction materials; A hazardous waste management plan; A solid waste management plan; and Sanitary/septic waste storage and disposal procedures. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 4-33 4. Storm Water Pollution Prevention Plans (SWPP) 4.4 STEP 4: PREPARE A PLAN FOR MAINTENANCE OF BMPS Proper maintenance of BMPs is an integral part of the effort to prevent storm water pollution. BMPs must be cleaned or replaced where design capacity is reduced by 50%. Procedures and activities for this purpose must be included in the SWPPP. Maintenance criteria are included in the BMP descriptions in Chapter 5. 4.5 STEP 5: COLLECT PERMIT-RELATED DOCUMENTS The following documents must be included in the SWPPP: Document AZPDES permit (AZG2003-001) NOI (as completed by the contractor) NPDES or AZPDES authorization number for the project. Other agreements with any state, local or federal agencies that affect the provisions or implementation of the SWPPP. Part IV.J Part IV.J.2 Part IV.J.3 AZC GP R eferenc e S ource www.adeq.state.az.us www.adeq.state.az.us Provided by ADEQ after NOI is approved. ADOT environmental clearance documents. In addition, a site specific inspection plan must be developed as part of the SWPPP. A standard ADOT inspection checklist is included in Appendix A. Identify and document the credentials of qualified inspectors. The credentials of a qualified inspector are described in the project specifications. 4.6 STEP 6: COMPY WITH APPLICABLE FEDERAL, STATE AND LOCAL PROGRAMS Chapter one described the federal, state and local soil and erosion control programs that must be followed to prevent pollution to the waters of the U.S. 4.7 STEP 7: DEVELOP A STE SPECIFIC INSPECTION PLAN An inspection plan must be developed as part of the SWPPP. A standard ADOT inspection checklist is included in Appendix A. Identify and show the credentials of qualified inspectors, as described in project specifications and in the SWPPP to simplify the completion of inspection reports in the field. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 4-34 5 BEST MANAGEMENT PRACTICES 5.0 INTRODUCTION ADOT requires contractors to prepare and implement a SSWPPP to control water pollution effectively during the construction process of all ADOT projects. As described in Chapter 4 of this manual, in order to complete the SWPPP for ADOT approval, the contractor is required to select those BMPs which will best control storm water pollution. This chapter provides instructions for the selection and implementation of BMPs. The BMPs described in this Chapter include both temporary and permanent erosion and sediment control practices. Each project presents unique conditions. These BMPs are provided as a "toolbox" to allow ADOT and the Contractor options to best address the requirements of the Arizona Construction General Permit. Disturbed Soil Area Management Limiting the amount of disturbed soil is a critical component in conducting an effective storm water management program. Section 104.09 of the Special Provisions states "Unless otherwise approved in writing, the contractor shall not expose an area greater than 750,000 square feet in any one location within the project limits until the erosion control devices proposed for that portion of the project have been installed and accepted by the Engineer.... In addition, unless otherwise approved by the Engineer, erosion control measures for each slope that is not scheduled to be re-disturbed within 21 days shall be placed not later than 14 days after construction activity has temporarily or permanently ceased for that portion of the work." The Engineer may elect to further restrict the size of the project's total disturbed area during the rainy season. 5.1 SOIL STABILIZATION BEST MANAGEMENT PRACTICES Soil stabilization consists of preparing the soil surface and applying one of the following BMPs, or a combination thereof, to disturbed soils areas. 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 5.1.7 5.1.8 5.1.9 Scheduling............................................................................. 36 Preserve Existing Vegetation..................................................38 Minibenches/Slope Roughening........................................... 40 Hydraulic Mulch.....................................................................44 Hydroseeding..........................................................................46 Soil Binders............................................................................48 Straw Mulch........................................................................... 54 Geotextiles, Plastic Covers, Erosion Control Blankets/Mats.............................................56 Compost/Wood Mulching.....................................................64 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-35 Scheduling 5.1.1 Scheduling Definition The development of a schedule for every project that includes sequencing of construction activities in conjunction with the implementation of construction site BMPs in order to reduce the amount and duration of soil exposed by construction activities. The purpose is to minimize erosion of disturbed soils by wind, rain, runoff, and vehicle tracking. Purpose To reduce the amount and duration of soil exposed to erosion. To ensure that BMPs are implemented in a timely manner as construction proceeds. Appropriate Applications Construction activities shall be planned to minimize the amount of disturbed land exposed to erosive conditions. Stabilization measures shall be installed and maintained as work progresses, not just at the completion of construction. 5-36 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Planning Considerations Schedule the installation of temporary and permanent controls as specified in the Construction General Permit. The schedule of construction activities and concurrent application of temporary and permanent BMPs is developed as part of the SWPPP. Schedule clearing and grubbing activity to allow existing vegetation to remain in place as long as possible. For larger projects, the contractor shall not expose more than 750,000 square feet in any location until temporary or permanent BMPs have been installed. Schedule shall include dates for significant long-term operations or activities that may have planned non-storm water discharges such as dewatering, sawcutting, grinding, drilling, boring, crushing, blasting, painting, hydro-demolition, mortar mixing, bridge cleaning, etc. Schedule shall include dates for installation of permanent drainage systems and runoff diversion devices. These devices should be installed as early as possible in the construction process. The schedule shall include non-storm water BMPs, waste management and materials pollution control BMPs. Stabilize non-active areas as specified in the CGP. Monitor weather forecast and adjust construction schedule to allow for the implementation of soil stabilization and sediment controls on all disturbed areas prior to the onset of rain. Inspections Verify that work is progressing in accordance with the schedule. Maintenance The schedule must be updated when changes are warranted or when directed by the Engineer. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-37 Preserve Existing Vegetation 5.1.2 Preserve Existing Vegetation Definition The carefully planned protection of trees and natural vegetated areas within the construction site or right-of-way in order to minimize the amount of bare soil exposed to erosive forces and provide vegetated areas to filter storm water runoff. Purpose Reduce soil erosion, sediment transport, and tracking. Reduce maintenance. Appropriate Application Protect trees and natural areas not in direct conflict with construction activities. Limitations Difficult on sites with restricted access. Requires planning and may limit area available for construction activity. Standards and Specifications 5-38 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Timing Evaluate existing vegetation early in the planning process to adjust grading limits around high quality natural areas. Areas to be preserved in place shall be clearly marked at the site and identified on the project plans. Preservation of existing vegetation shall conform to scheduling requirements set forth in the special provisions. Clearing and grubbing and other soil-disturbing construction activities shall not be permitted prior to preservation of existing vegetation. Design and Layout Areas to be preserved shall be marked with highly visible, non-metallic, temporary fencing as described in the project specifications. Temporary fencing shall be placed beyond the "dripline" of a tree by a distance that is 1� times the length of the "dripline" radius. Temporary roads shall be constructed to minimize disturbance to existing vegetation and remain within limits of disturbance of permanent road. Construction materials, equipment storage, and parking areas shall be located where they will not cause root compaction. Waste materials including vegetation to be removed shall not be stored within the preserved area. Construction Activities Where tree roots are disturbed, they shall be covered with soil as soon as possible. Damaged roots and limbs shall be cut cleanly. Seriously damaged trees shall be examined a trained arborist. Remove and replace trees if they are damaged seriously enough to affect their survival. Aerate soil where compaction occurs from construction activity. Immediately repair damage to irrigation systems. Inspections Follow inspection schedule required in CGP Part IV.H. Inspect the preservation fencing to ensure that it is intact and that there has been no encroachment into the preservation area. Evaluate preserv-in-place vegetation for signs of stress. Maintenance Maintain preservation fencing as needed. After all other work is complete, fencing and barriers shall be removed last. Address unhealthy and declining vegetation as described in project specifications. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-39 Minibenches/Slope Roughening 5.1.3 Minibenches/Slope Roughening Definition Terracing and roughening are techniques for creating furrows, terraces, serrations, stair-steps or track-marks on the soil surface. Purpose To improve water infiltration. To increase the effectiveness of temporary and permanent soil stabilization practices. Appropriate Applications Large engineered slopes, primarily cuts in rural settings. Soils prone to erosion. Prior to application of permanent seeding. Limitations Not appropriate on rock slopes. Must be constructed as slope is cut. 5-40 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Standards and Specifications Planning Considerations Minibenching and slope roughening shall be constructed from the top of a cut slope down. Design Minibenches, terraces, furrows, and other horizontal roughening techniques shall follow the contour. Inspections and Maintenance Follow inspection schedule required in the CGP Part IV.H. Where horizontal roughening falls away from the contour, additional BMPs may be required to protect the slope. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-41 5-42 ADOT Erosion and Pollution Control Manual For Highway Design and Construction ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-43 Hydraulic Mulch 5.1.4 Hydraulic Mulch Definition Hydraulic mulch consists of applying a mixture of shredded wood fiber or a hydraulic matrix (e.g., bonded fiber matrix), and a stabilizing emulsion or tackifier with hydro-mulching equipment. This will protect exposed soil from erosion by raindrop impact or wind. This is one of five temporary soil stabilization alternatives to consider. Purpose Reduce soil erosion through temporary stabilization. Appropriate Applications Temporary protection of disturbed areas until permanent measures (such as vegetation) are installed. Temporary protection of disturbed areas that must be re-disturbed following an extended period of inactivity. Hydraulic matrices typically are effective for longer periods of time. Limitations Wood fiber hydraulic mulches are typically short-lived (less than a growing season). Hydraulic tackifiers typically require 24 hours to cure to be effective. Therefore, 5-44 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices should not be applied immediately prior to a storm event. Standards and Specifications Apply as specified in project documents or by manufacturer. Soil surface must be loose at time of application. Area to be mulched shall be completely covered. Avoid overspray onto existing pavements, structures and vegetation. Selection of hydraulic mulches by the contractor must be approved by the Engineer prior to use. Inspections Follow inspection schedule required in the CGP Part IV.H. Inspect after all rainfall events. Maintenance Maintain an unbroken ground cover throughout the period of construction the soils are not being reworked. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-45 Hydroseeding 5.1.5 Hydroseeding Definition Hydroseeding typically consists of applying a mixture of fiber, seed, fertilizer, and stabilizing emulsion with hydro-mulch equipment, which protects exposed soils from erosion by water and wind. This is one of five temporary soil stabilization alternatives to consider. Purpose Reduce soil erosion through temporary soil stabilization. Appropriate Applications Application of seed for permanent revegetation and stabilization of disturbed soils. Temporary protection of disturbed areas until permanent measures (e.g., vegetation) are installed. Temporary protection of disturbed areas that must be re-disturbed following an extended period of inactivity. Limitations Straw mulching may be necessary in addition to hydroseeding in order to promote establishment of vegetation. 5-46 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Steep slopes are difficult to protect with temporary seeding. Dry or cold weather will affect vegetative establishment. Standards and Specifications Site conditions must be evaluated prior to determining suitable species selection and application rates. Attributes such as soil types, topography, local climate and season, maintenance requirements, proximity of sensitive areas (e.g., live streams), and existing native vegetation types. Prior to use, ADOT shall approve application rates for mulches, tackifier, soil amendments and seed mixtures as per specifications prior to application. All seed shall be in conformance with requirements of the project specifications. Areas to be seeded shall be filled as described in project specifications. Soil shall be loose and friable. Inspections Follow inspection schedule required in the CGP Part IV.H and project specifications. Maintenance Any temporary revegetation efforts that do not provide adequate cover must be revegetated as required by the Engineer. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-47 Soil Binders 5.1.6 Soil Binders Definition Soil binders consist of applying and maintaining polymeric or lignin sulfonate soil stabilizers or emulsions. Soil binders are materials applied to the soil surface to temporarily prevent waterinduced erosion of exposed soils on construction sites. Soil binders typically also provide dust, wind, and soil stabilization (erosion control) benefits. This is one of five temporary soil stabilization alternatives to consider. Purpose Reduce soil erosion through temporary soil stabilization. Appropriate Applications Temporary protection of disturbed areas until permanent measures (e.g., vegetation) are installed. Temporary protection of disturbed areas that must be re-disturbed following a period of inactivity. Because they can be often incorporated back into the work, they may be a good choice where grading activities will soon resume. 5-48 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Limitations Soil binders are temporary in nature and may require reapplication, especially after heavy or prolonged rainfall. Typically require a cure time of approximately 24 hours. Easily disturbed by vehicular or pedestrian traffic. Do not adhere well to compacted or dense (clay) soils. May not perform well under conditions of low relative humidity or low temperatures. May be slippery if oversprayed onto vehicular travelways. Standards and Specifications General Considerations Site conditions (soil type, temperature and humidity) must be evaluated prior to determining appropriate soil binder type. Regional soil types will dictate appropriate soil binders to be used. Must be environmentally benign (non-toxic to existing plants and wildlife). Selecting a Soil Binder Properties of common soil binders used for erosion control are provided on Table 5.1.6. In consultation with the Engineer, use Table 5.1.6 to select an appropriate soil binder. Factors to consider when selecting a soil binder include the following: Suitability to situation � Consider where the soil binder will be applied: if it needs a high resistance to leaching or abrasion, and whether it needs to be compatible with any existing vegetation. Determine the length of time soil stabilization will be needed, and if the soil binder will be placed in an area where it will degrade rapidly. In general, slope steepness is not a discriminating factor for the listed soil binders. The soil binders in Table 5.1.6 may also be used for dust control using the provided dust control application rates. The dust control application rates will not be adequate to provide protection from water-induced erosion. Soil types and surface materials � Fines and moisture content are key properties of surface materials. Consider a soil binder's ability to penetrate, likelihood of leaching, and ability to form a surface crust on the surface materials. Frequency of application � The frequency of application can be affected by subgrade conditions, surface type, traffic volumes, climate, and maintenance schedule. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-49 Soil Binders Frequent applications could lead to high costs. Application frequency may be minimized if the soil binder has good penetration, low evaporation, and good longevity. Consider also that frequent application will require frequent equipment clean-up. After considering the above factors, the soil binders in Table 5.1.6 will be generally appropriate as follows: Copolymer: Appropriate for long term soil stabilization in areas where cross-traffic might occur, or where stabilization needs to be achieved in conjunction with preserving existing vegetation. Longevity can be up to 2 years, it has a high resistance to abrasion, and is compatible with existing vegetation. However, it is also relatively costly which makes it less desirable for short-term or frequent applications. Lignin sulfonate: Appropriate for short- or medium-term soil stabilization applications in low traffic areas. The moderate relative cost makes it less desirable to reapply frequently, though it typically lasts longer than psyllium or guar. With only moderate penetration and a low resistance to abrasion, it would be more suited to areas which will not be disturbed frequently by construction activities. Psyllium/Guar: Appropriate for typical soil stabilizing situations or short-term applications. Because of the relatively low cost, they can be applied more frequently. Their high penetration provides good stabilization but their moderate resistance to abrasion limits their longevity. They are not very compatible with vegetation. Applying Soil Binders After selecting an appropriate soil binder, the untreated soil surface must be prepared before applying the soil binder. The untreated soil surface must contain sufficient moisture to assist the agent in achieving uniform distribution. In general, the following steps shall be followed: Follow manufacturer's recommendations for application rates, pre-wetting of application area and cleaning of equipment after use. Prior to application, roughen embankment and fill areas. Track walking shall only be used where rolling is impractical. Soil binders shall not be applied during or immediately before rainfall. Avoid over-spray onto the traveled way, sidewalks, lined drainage channels, sound walls, and existing vegetation. Do not apply soil binders to frozen soil, areas with standing water, under freezing or rainy conditions, or when temperature is below 4 � (40�F). 5-50 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Temporary Best Management Practices More than one treatment is often necessary, although the second treatment may be diluted or have a lower application rate. Generally, soil binders require a minimum curing time of 24 hours before they are fully effective. Refer to manufacturer's instructions for specific cure times. For liquid agents: Crown or slope ground to avoid ponding. Uniformly pre-wet ground at 0.14 to 1.4 l/m� (0.03 to 0.3 gal/yd�) or according to manufacturer's recommendations. Apply solution under pressure. Overlap solution 150 to 300 mm (6 to 12 inches). Allow treated area to cure for the time recommended by the manufacturer, typically, at least 12 hours. Apply second treatment before the first treatment becomes ineffective, using 50% application rate. In low humidities, reactivate chemicals by re-wetting with water at 0.5 to 0.9 l/m� (0.1 to 0.2 gal/yd�). Maintenance and Inspection Reapplying the selected soil binder may be needed for proper maintenance. High traffic areas shall be inspected on a daily basis, and lower traffic areas should be inspected on a weekly basis. After any rainfall event, the Contractor is responsible for maintaining all slopes to prevent erosion. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-51 Soil Binders Properties of Soil Binders for Erosion Control C hemicals C opolymer - Forms semipermeable transparent crust. - Resists ultraviolet radiation and moisture induced breakdown High Low Moderate Moderate Low High 1 to 2 years 24 hours Lignin S ulfonate - Paper industry waste produce - Acts as dispersing agent- Best in dry climates- Can be slippery Moderate Low Moderate Moderate High Low 6 months to 1 year 24 hours P oor Ps yllium Guar Comments - Effective on dry, hard soils - Forms a crust - Effective on dry, hard soils - Forms a crust Relative Cost Environmental Hazard Penetration Evaporation Resistance to Leaching Resistance to Abrasion Longevity Minimum Curing Time before Rain Low Low High Moderate High Moderate 3 to 6 months 24 hours P oor Low Low High Moderate High Moderate 3 to 6 months 24 hours P oor Biologically Degradable No Yes Powder Yes, but dissolves on rewetting Water Apply 110-220 kg/ha (100-200 lbs./ac) with 5602,200 kg/ha (5002,000 lbs./ac) fiber mulch. Apply at 45-70 K/ha (40-60 lbs./ac). Compatibility with Good Existing Vegetation Mode of Degradation Labor Intensive Specialized Application Equipment Liquid/Powder Surface Crusting Clean-Up Chemically Degradable No Yes Liquid Yes Solvents Biologically/PhysicallBiologically y/Chemically Degradable Degradable No Yes Powder No Yes Powder Yes, but dissolves on Yes, but dissolves rewetting on rewetting Solvents Water Erosion Control Application Rate Apply 170 kg/ha (150 lb./ac) with Apply 800-1,000I/ha Apply 5,600-6,500 560-2,200 kg/ha (85-110 gal/ac). I/ha (600-700 gal/ac). (500-2,000 lbs./ac) fiber mulch. Loosen surface 2550mm (1-2 in). Need Apply 280-520 L/ha Apply 170 K/ha 4-8% fines. Apply (30-55 gal/ac). (150 lbs./ac). 470-1,900 l/ha (50200 gal/ac). Dust Control Application Rate Table 5.1.6 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-52 5. Temporary Best Management Practices ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-53 Straw Mulch 5.1.7 Straw Mulch Definition Straw mulch consists of placing a uniform layer of straw and incorporating it into the soil by mechanical means (e.g., a drill or studded roller) or anchoring it with tackifier. This is one of five temporary soil stabilization alternatives to consider. Purpose Reduce soil erosion through temporary soil stabilization. Appropriate Applications Straw mulch is used for soil stabilization as a temporary surface cover on disturbed areas until soils can be prepared for final stabilization. Typically used in combination with temporary and/or permanent seeding applications to enhance plant establishment. Limitations Where mechanical straw blowers are used, application areas are typically limited to within approximately 150 feet of equipment. Therefore, for large slopes frequent mobilizations and applications are necessary. Application of straw mulch by hand is typically expensive. 5-54 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Potential for accidental introduction of undesirable weed species. Blown straw is potentially a nuisance when applied in urban areas. Standards and Specifications Materials shall conform to and shall be applied at rates specified in special provisions. Straw shall be certified to be free of weeds and invasive species. When applied by blower, avoid overspray onto existing pavements, structures and vegetation. On slopes less steep than 2 (horizontal): 1 (vertical) and where mechanical action will not contribute to soil compaction, straw can be "punched" into the soil using a knife-blade roller or a straight bladed coulter ("crimper"). For small areas, straw can be anchored by hand tools. Inspections Follow inspection schedule required in the CGP Part IV.H. Maintenance Reapply mulch when more than 20% bare ground is exposed in application area. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-55 Geotextiles, Plastic Covers, Erosion Control Blankets/Mats 5.1.8 Geotextiles, Plastic Covers and Erosion Control Blankets/Mats Definition A natural (excelsior, straw, coconut, etc.) or synthetic (usually polyethelene) material installed to reduce soil erosion by wind or water. This is one of five soil stabilization alternatives to consider. Purpose Reduce rainfall impact. Provide a microclimate to promote seedling establishment. Protect exposed soil from wind and rain. Reduce erosiveness of concentrated flows. Appropriate Applications Steep slopes (typically greater than 3 horizontal: 1 vertical). Slopes with highly erosive soils or where the erosion hazard is high. Slopes adjacent to bodies of water. Concentrated flow areas such as ditches and channels with flows exceeding 3.3 ft/ sec. (refer to ADOT Hydraulic Manual for channel lining criteria). In areas where plant establishment is likely to be slow. Areas inaccessible to hydraulic equipment. 5-56 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Stockpiles. Costly. Not suitable for excessively rocky sites or rough slopes. Not suitable for areas where vegetation will be mowed. Plastic sheeting is easily disturbed and must be removed and disposed of prior to Application of permanent soil stabilization measures. Plastic also results in increased runoff rates. May trap wildlife. Limitations Standards and Specifications Material Selection There are a wide variety of types and materials from which to choose. Selection shall be based on needs for the specific project. Factors to consider include: Cost: materials, site preparation, installation. Effectiveness: reduction of erosion, flow velocity, and runoff. Acceptability: environmental compatibility, regulatory, and aesthetic concerns. Vegetation enhancement: moisture retention, temperature modification. Installation: durability, longevity, ease of installation, safety. Maintenance. Geotextiles: Material shall be woven polypropylene fabric with minimum thickness of 0.5 inches, minimum width of 12 feet and shall have minimum tensile strength of 50 lbs/ ft (0.67 kN) (warp) 25 lbs/ ft. (0.36 kN) (fill) in conformance with the requirements in ASTM Designation: D 4632. The permittivity of the fabric shall be approximately 0.07 sec-� in conformance with the requirements in ASTM Designation: D4491. The fabric shall have an ultraviolet (UV) stability of 70 percent in conformance with the requirements in ASTM designation: D4355. Geotextile blankets shall be secured in place with wire staples or sandbags and by keying into tops of slopes to prevent infiltration of surface waters under Geotextiles may be reused if, in the opinion of the RE, they are suitable for the use intended. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-57 Geotextiles, Plastic Covers, Erosion Control Blankets/Mats Plastic Covers: Material shall be polyethylene sheeting and shall have a minimum thickness of 6 mm. Plastic covers shall be anchored by sandbags placed no more than 10 feet apart and by keying into the tops of slopes to prevent infiltration of surface waters under the plastic. All seams shall be taped or weighted down their entire length, and there shall be at least 12 inches to 24 inches overlap of all seams. Plastic covers may be reused if, in the opinion of the engineer, they are suitable for the use intended. Erosion Control Blankets/Mats: Blankets and Mats are available in materials with a wide variety of susceptibility to biological and photo-degradation. The most common materials in order of least to most durable are: Agricultural straw. Jute fiber. Wood fiber (Excelsior). Coconut fiber (coir). Site Preparation Proper site preparation is essential to ensure complete contact of the blanket or matting with the soil. Grade and shape the area of installation. Remove all rocks, clods, vegetation or other obstructions so that the installed blankets or mats will have complete, direct contact with the soil. Contractor shall cut material to fit around large boulders. If areas is to be seeded, prepare soil as directed in the project specifications before applying covering. Seeding Seed the area before blanket installation for erosion control and revegetation. Seeding after mat installation is often specified for turf reinforcement application. When seeding prior to blanket installation, all check slots and other areas disturbed during installation must be re-seeded. Where soil filling is specified, seed the matting and the entire disturbed area after installation and prior to filling the mat with soil. Anchoring U-shaped wire staples, metal pins or wooden stakes can be used to anchor mats and blankets to the ground surface. Staples shall be made of .12 inch steel wire and shall be U-shaped with 8-inch legs and 2-inch crown. Wire staples shall be minimum of 11 gauge. 5-58 ADOT Erosion and Pollution Control Manual For Highway Design and Construction Metal stake pins shall be 0.188-inch diameter steel with a 1.5 inch steel washer at the head of the pin. Wire staples and metal stakes shall be driven flush to the soil surface. All anchors shall have sufficient ground penetration to resist pullout by wind. Longer anchors may be required for loose soils. Installation on Slopes Always consult the manufacturer's recommendations for installation. In general, these will be as follows: 1. Begin at the top of the slope and anchor the blanket in a 12-inch deep trench. Backfill trench, tamp earth firmly and staple every 12 inches. 2. Unroll blanket downslope in the direction of water flow. 3. Overlap the edges of adjacent parallel rolls 4 inches and staple every 12 inches. 4. When blankets must be spliced, place blanket ends in common trench as described above with 6-inch overlap. Staple through overlapped area, approximately 6 inches apart. 5. Lay blankets loosely and maintain direct contact with the soil. Do not stretch. 6. Staple blankets sufficiently to anchor blanket and maintain contact with the soil. Staples shall be placed down the center and staggered with the staples placed along the edges. 7. On steep slopes, 1:1 (V:H) to 1:2 (V:H), require a minimum of 2 staples/yd�. Moderate slopes, 1:2 (V:H) to 1:3 (V:H), require a minimum of 1 � staples/yd�, placing 1 staple/yd on centers. Gentle slopes require a minimum of 1 staple/yd�. Installation in Channels Always consult the manufacturer's recommendations for installation. In general, these will be as follows: 1. Dig initial anchor trench 12 inches deep and 6 inches wide across the channel at the lower end of the project area. 2. Excavate intermittent check slots, 6 inches deep and 6 inches wide across the channel at 25- to 30 foot-intervals along the channels. 3. Cut longitudinal channel anchor slots 4 inches deep and 4 inches wide along each side of the installation to bury edges of matting, whenever possible extend matting 2 inches to 3 inches above the crest of the channel side slopes. 4. Beginning at the downstream end and in the center of the channel, place the initial end of the first roll in the anchor trench and secure with fastening devices at 12 inches intervals. Note: matting will initially be upside down in anchor trench. 5. In the same manner, position adjacent rolls in anchor trench, overlapping the preceding roll a minimum of 3 inches. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-59 Geotextiles, Plastic Covers, Erosion Control Blankets/Mats 6. Secure these initial ends of mats with anchors at 12-inch intervals, backfill and compact soil.Unroll center strip of matting upstream. Stop at next check slot or terminal anchor trench. Unroll adjacent mats upstream in similar fashion, maintaining a 3-inch overlap. Fold and secure all rolls of matting snugly into all transverse check slots. Lay mat in the bottom of the slot then fold back against itself. Anchor through both layers of mat at 12-inch intervals, then backfill and compact soil. Continue rolling all mat widths upstream to the next check slot or terminal anchor trench. 7. Alternate method for non-critical installations: 1. Place two rows of anchors on 6-inch centers at 25- to 30-foot intervals in lieu of excavated check slots. 2. Shingle-lap spliced ends by a minimum of 12 inches apart on 12-inch intervals. 3. Place edges of outside mats in previously excavated longitudinal slots, anchor using prescribed staple pattern, backfill and compact soil. 4. Anchor, fill and compact upstream end of mat in a 12 inches by 6 inches terminal trench. 5. Secure mat top ground surface using U-shaped wire staples, geotextile pins, or wooden stakes. 6. Seed and fill turf reinforcement matting with soil, if specified. Soil filling (if specified for turf reinforcement) Always consult the manufacturer's recommendations for installation. Do not drive tacked or heavy equipment over mat. Avoid any traffic over matting if loose or wet soil conditions exist. Use shovels, rakes or brooms for fine grading and touch up. Smooth out soil filling; just exposing top netting of mat. Removal When no longer required for the work, coverings shall become the property of the Contractor and shall be disposed of outside the highway right of way in conformance with the special provisions. Inspections Follow inspection schedule required in CGP Part IV.H. Erosion may occur under blankets in areas were contact with soil has been compromised. This damage may be difficult to detect and repair. Maintenance Re-anchor loosened matting and replace lost matting and staples as required. Repair slope or channel damage before re-installing matting if washout or breakage occurs. 5-60 ADOT Erosion and Pollution Control Manual For Highway Design and Construction ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-61 5-62 ADOT Erosion and Pollution Control Manual For Highway Design and Construction ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-63 Compost/Wood Mulching 5.1.9 Compost/Wood Mulching Definition Compost or wood mulching consists of applying a mixture of compost, shredded wood mulch or bark. Purpose To temporarily protect exposed soil from wind, raindrop impact, increase infiltration and reduce runoff. To provide a suitable microclimate to promote seed germination. To prevent surface compaction or crusting. Appropriate Applications Temporary soil stabilization. Shredded bark mulch may be applied to smaller drainage channels to reduce runoff velocities and soil erosion. Sensitive areas may be mulched at the end of a day's operations if rain is predicted. In conjunction with seed to encourage seed germination and establishment. 5-64 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Mulches that are susceptible to erosion by wind or water are anchored to the soil using a variety of techniques. Crimping, tracking, disking or punching. Hydraulic bonding using a variety of organic or acrylic tackifiers. Covering with netting and stapled Limitations Susceptible to wind disturbance. Potential for accidental introduction of undesirable weed species. Areas where hydraulically bonded mulches are to be applied must be accessible to equipment used in the process. Hydraulically bonded mulches require 24 hours to dry before rainfall occurs to be effective. Shredded wood mulch will not withstand significant concentrated flows and is prone to sheet erosion. Standards and Specifications Mulch Selection There are many different types of mulches. Selection on type shall be based on type of application and site conditions. Prior to use, choice of mulch shall be approved by the Landscape Architect. Shredded wood and wood chips)�may be available from existing suitable vegetation to be cleared from site. Compost � typically applied as a component of seeding applications; shall be tested as described in the special provisions for biotic and abiotic factors. Installation May be applied by hand or by mechanical or hydraulic methods. Follow inspection schedule required in CGP Part IV.H. Inspect for exposed areas of soil or where covering is broken. Inspections Maintenance Reapply mulch when more than 20% bare ground is exposed in application area. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-65 5. Temporary Best Management Practices 5-66 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Temporary Best Management Practices 5.2 CONCENTRATED FLOW CONVEYANCE CONTROLS Temporary concentrated flow conveyance controls consist of a system of installations or BMPs that are used alone or in combination to intercept, divert, convey, and discharge concentrated flows with a minimum of soil erosion, both on-site and downstream (offsite). Temporary concentrated flow conveyance controls may be required to direct run-on around or through the project in a non-erodible fashion. Temporary concentrated flow conveyance systems include the following BMPs: 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 Earth Dikes/Drainage Swales................................................ 68 Cut to Fill Slope Transitions................................................ 70 Erosion Protection at Structures.............................................72 Rock Outlet Protection.......................................................... 74 Slope Drains.......................................................................... 76 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-67 Earth Dikes/Drainage Swales 5.2.1 Earth Dikes/Drainage Swales Definition Structures that intercept, divert, and convey surface runoff (generally sheet flow) to a desired location. Purpose To divert runoff away from erodible surfaces. To divert runoff toward sediment trapping devices. Appropriate Applications At the base of fill slopes where runoff begins to concentrate. At the top of slopes to control rill and gully erosion. At bottom and mid-slope locations to intercept sheet flow and convey concentrated flows. To divert runoff toward a stabilized watercourse or drainage structure. To divert sediment laden water to sediment trapping device. To divert storm water around construction staging areas. 5-68 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Limitations Runoff must be diverted into existing or stabilized drainages or sediment basins. High runoff velocities may scour and erode dikes and swales. May be necessary to combine with other BMPs such as check dams, blankets, and sediment logs or riprap. Does not control erosion or remove sediment. Standards and Specifications Must be sized correctly for expected flows. Swales shall be lined where high runoff velocities are expected. Dikes shall be stabilized by compaction or other means such as erosion control blankets or riprap. Provide stabilized outlets. Where runoff will carry sediment, divert flow into sediment traps. Where installed at construction traffic crossings, the top width may be wider and side slopes may be flatter. When possible, dikes and swales shall be installed early in the construction process. Shall not adversely impact adjacent properties and must conform to local floodplain management regulations. Inspections Follow inspection schedule required in CGP Part IV.H. Inspect for washouts and failure of associated BMPs. Check outlet stabilization for signs of erosion. Maintenance Repair as needed. Repair where damaged by construction equipment. If material is added to repair the dike it must be properly recompacted. Where flows are directed into sediment traps, maintain as described in Sediment Trap BMP. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-69 Cut to Fill Slope Transitions 5.2.2 Cut to Fill Slope Transitions Definition Rock riprap placed in cut-to-fill slope transitions. Purpose To reduce erosion at cut-to fill transitions. Appropriate Applications Where concentrated surface flows must be conveyed from a cut ditch, down to the toe of the adjoining downstream fill slope. Limitations Rock riprap transitions reduce erosion only when they have been sized and built properly. Standards and Specifications Width of riprap application at beginning of the cut-to-fill transition shall match width of roadside ditch. Width of rock riprap at end of cut-to-fill transition shall be 50% greater than the width of rock riprap at the beginning of the cut-to-fill transition. 5-70 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Cut-to-fill transition shall terminate at a planned or existing stabilized drainage. Rock shall be placed by hand or mechanical means to achieve complete coverage at the transition. Dumping of riprap may be necessary. Riprap shall be embedded into slopes. Riprap shall be placed to ensure that the center of the transition is lower than the edges and avoid runoff flow over unprotected soil. Size of rock used must be large enough to withstand expected design flow through the transition. Riprap greater than 6 inches shall be wire-tied if required by traffic recovery area. Inspections and Maintenance Follow inspection schedule required in the CGP Part IV.H. Inspect for signs of slope erosion under and around the rock protection, check for erosion and displacement of rock at the outlet. Replace rock and repair as needed. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-71 Erosion Protection at Structures 5.2.3 Erosion Protection at Structures Definition Rock riprap place along soil interface of concrete and metal structures Purpose To reduce or eliminate the potential for undercutting at structures. Appropriate Applications Place at any structure that abuts a soil surface and where concentration and/or velocity of storm water is great enough to cause erosive flows. Limitations None Planning Considerations Rock interface protection is effective when the rock is sized and placed properly. Standards and Specifications Design and size as specified in the contract documents or as directed by the Engineer. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-72 5. Best Management Practices Use sound, durable, and angular rock for best results. Follow inspection schedule required in the CGP Part IV.H. Inspect for signs of erosion and undercutting around the structure. Inspections Maintenance Replace rock and repair erosion damage as needed. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-73 Rock Outlet Protection 5.2.4 Rock Outlet Protection Definition Rock riprap or grouted riprap placed at outlets ends of culverts, conduits, or channels. Purpose To prevent scour and reduce velocity of exiting storm water flows. Appropriate Applications Where discharge velocities and energies at the outlets of culverts, pipes or channels are sufficient to erode the downstream channel. At discharge outlets that carry continuous flows of water. At points where lined conveyances discharge to unlined conveyances. Limitations Loose rock may be washed away during high flows. Freeze/thaw cycles may break up grouted riprap. Standards and Specifications 5-74 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Grouted or wire-tied rock riprap can minimize maintenance requirements. Rock must be sized and placed properly to be effective. Refer to ADOT Drainage Manual. A sediment trap below the outlet is recommended if runoff is sediment-laden. Use sound, durable and angular rock for best results. Follow inspection schedule required in the CGP Part IV.H. Inspect for displacement of riprap or damage to underlying fabric, and signs of scour beneath the riprap or around the outlet. Inspections Maintenance Replace rock and repair apron and slopes as needed. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-75 Slope Drains 5.2.5 Slope Drains A temporary drain used to intercept and convey runoff into a stabilized drainage. Definition Purpose To prevent soil erosion. Appropriate Applications Installed where slopes may be eroded by surface runoff. Typically used in conjunction with top of slope diversion berms, dikes or swales or temporary embankment curbs. Where final road grades are completed but remain unpaved. May be used as emergency spillway for sediment basin. Limitations Volume of runoff to be conveyed must not exceed capacity of structure. Larger areas require a paved spillway, rock lined channel or additional pipes. May become clogged or overcharged during large storms forcing water around pipe. Failure causes extreme slope erosion. 5-76 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5. Best Management Practices Standards and Specifications Design and Layout Size of area to be drained must be taken into consideration. Typically, no more than 5 acres shall be drained by one pipe. For larger areas, use a rock-lined channel or a series of pipes. Direct runoff into stabilized drainages. Inlet installation is critical because it is a common point of failure. Consider use of erosion control blanket at inlets. Outfall must be protected by riprap. For that reason, installation is typically limited to maximum grades of 2:1(v:h). Installation on steeper slopes is difficult. Consider flared end section for high volume discharges. Slope drains can be placed on the surface of slopes or installed below grade. Recommended materials for pipes are PVC, ABS or comparable. If a pipe slope drain is conveying sediment-laden water all flows shall be directed into a sediment-trapping device. Installation Install as directed in contract documents. Drains shall be perpendicular to slope contours. All slope drain pipe sections shall be securely fastened together with a watertight seal and shall be securely anchored into the soil. Follow requirements for diversion dikes/swales to construct diversions used to direct runoff into a slope drain. Compact soil around and under inlet, outlet, and along length of pipe. The area below the outlet must be stabilized with a riprap apron. Refer to Erosion Protection and Structures Detail E-2. Follow inspection schedule required in Construction General Permit Part IV.H. Inspect for structural integrity, blockage, and stability at the inlet and outlet. Inspect for downstream scour; remedy as required. Inspections Maintenance Reinforce inlet with compacted soil or sandbags if problems occur. If outlet flow is directed to a sediment-trapping device, sediment should removed as specified in for that device. ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5-77 5-78 ADOT Erosion and Pollution Control Manual For Highway Design and Construction 5.3 SEDIMENT CONTROL BEST MANAGEMENT PRACTICES Temporary sediment control practices include those measures that intercept and slow or detain the flow of storm water to allow sediment to settle and be trapped and include the following BMPs: 5.3.1 Sediment Control Berm.......................... |
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