Alaska; Stormwater Guidance Manual - Juneau

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City and Borough of Juneau

Stormwater Guidance ManualDRAFT

March 2009


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City and Borough of Juneau

STORMWATER GUIDANCE MANUAL

DRAFT

March 2009

Prepared for:City and Borough of Juneau

155 South Seward StreetJuneau, AK 99801

Prepared by:

Project 135-12556-09001


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City and Borough of JuneauDraft Stormwater Guidance Manual

TABLE OF CONTENTS

Title Page No.

Acknowledgments........................................................................................................................................ iv

Chapter 1. Introduction..............................................................................................................................1-1Background and Objectives for Manual .................................................................................................... 1-1

Overview of Stormwater Management Measures.........................................................................1-1Objective.......................................................................................................................................1-2 What This Manual Addresses ....................................................................................................... 1-2

Geographic Considerations........................................................................................................................1-3Montana Creek..............................................................................................................................1-5Duck Creek and Jordan Creek ...................................................................................................... 1-6Douglas Island ..............................................................................................................................1-6Direct Discharges to Large Water Bodies.....................................................................................1-7Steep Hillsides ..............................................................................................................................1-7Unpopulated Areas ....................................................................................................................... 1-7

Applicability to State and Interjurisdictional Projects ...............................................................................1-8Relationship of This Manual to Federal, State and Local Regulatory Requirements ................................ 1-8

Chapter 2. How to Use This Manual..........................................................................................................2-1

Chapter 3. Stormwater Quality ..................................................................................................................3-1Background................................................................................................................................................3-1 Thresholds and Exemptions.......................................................................................................................3-1

Source Control ..............................................................................................................................3-1

Water Quality Treatment ..............................................................................................................3-2Source Control ........................................................................................................................................... 3-4

General BMPs for Commercial Development..............................................................................3-4Site-Specific BMPs for Commercial Development...................................................................... 3-7BMPs for Residential Development ...........................................................................................3-21

Water Quality Treatment ......................................................................................................................... 3-29Biofiltration Swale......................................................................................................................3-31Filter Strip...................................................................................................................................3-38Infiltration Basin ......................................................................................................................... 3-43Wet Pond.....................................................................................................................................3-47Constructed Wetland...................................................................................................................3-54Catch Basin Insert.......................................................................................................................3-59

Filtration......................................................................................................................................3-62 Hydrodynamic Separator ............................................................................................................ 3-68Oil-Water Separator....................................................................................................................3-70Spill Control Device ...................................................................................................................3-76Flow Splitter ...............................................................................................................................3-79Snow Disposal Facility ...............................................................................................................3-83Emerging Technologies ..............................................................................................................3-92

Chapter 4. Stormwater Quantity ................................................................................................................4-1


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Background................................................................................................................................................4-1 Thresholds and Exemptions.......................................................................................................................4-2

Source Control ..............................................................................................................................4-2Flow Reduction.............................................................................................................................4-3

Stormwater Quantity Source Control.........................................................................................................4-4Large-Scale Site Design................................................................................................................4-4

Small-Scale Site Design................................................................................................................4-4Implementation .............................................................................................................................4-6

Flow Reduction..........................................................................................................................................4-8Runoff Dispersion.........................................................................................................................4-9Rain Garden ................................................................................................................................4-15Downspout Infiltration Systems: Trench and Dry Well .............................................................4-19Perforated Stub-Out Connections ...............................................................................................4-24

Chapter 5. Conveyance Systems and Hydraulic Structures ....................................................................... 5-1Background................................................................................................................................................5-1 Design Event Storm Frequency .................................................................................................................5-1Determination of Design Flows .................................................................................................................5-2Off Site Analysis........................................................................................................................................5-2

Backwater Analysis ...................................................................................................................................5-2Conveyance System Route Design ............................................................................................................5-3Easements, Access, and Dedicated Tracts .................................................................................................5-3

Easements, Access, and Dedicated Tracts .................................................................................... 5-3Pipe System Design Criteria ...................................................................................................................... 5-4

Analysis Methods ......................................................................................................................... 5-4Acceptable Pipe Sizes ...................................................................................................................5-5Pipe Materials ...............................................................................................................................5-5Pipe Slope and Velocity................................................................................................................5-6Pipes on Steep Slopes ................................................................................................................... 5-7Pipe System Layout Criteria ......................................................................................................... 5-7Pipe Structure Criteria...................................................................................................................5-8

Outfalls.......................................................................................................................................................5-9 General Design Criteria for Outfall Features................................................................................5-9Tightline Systems ....................................................................................................................... 5-11

Culvert Criteria ........................................................................................................................................ 5-11Culvert Design Criteria...............................................................................................................5-12Fish Passage Criteria...................................................................................................................5-12

Open Conveyances...................................................................................................................................5-13Private Drainage Systems ........................................................................................................................ 5-14

Discharge Locations....................................................................................................................5-14Drainage Stub-Outs.....................................................................................................................5-14

Chapter 6. Stormwater Site Plan................................................................................................................6-1

Background................................................................................................................................................6-1 Threshold ...................................................................................................................................................6-1Exemptions ................................................................................................................................................6-1Plan Elements.............................................................................................................................................6-1

Cover Sheet...................................................................................................................................6-1Project Engineer's Certification .................................................................................................... 6-2Phased Project Submittals.............................................................................................................6-2Proposed Project Description........................................................................................................6-2Site Map........................................................................................................................................6-2


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Schedule of Structures ..................................................................................................................6-3General Drawing Site and/or Grading Plan Sheets.......................................................................6-4Plan and Profile Sheet...................................................................................................................6-4BMP Design..................................................................................................................................6-5Off Site Analysis...........................................................................................................................6-5Maintenance Plan..........................................................................................................................6-5

Pollution Source Control...............................................................................................................6-5

References................................................................................................................................................. R-1

Appendix A. Small Project Stormwater Management..............................................................................A-1Water Quality............................................................................................................................................A-1

Source Control ............................................................................................................................. A-1Water Quality Treatment .............................................................................................................A-1

Water Quantity..........................................................................................................................................A-1Source Control ............................................................................................................................. A-1Runoff Reduction.........................................................................................................................A-1

Conveyance...............................................................................................................................................A-1 Stormwater Site Plan.................................................................................................................................A-2

Appendix B. Hydrologic Analysis and Design Methodology .................................................................. B-1Introduction............................................................................................................................................... B-1

Hydrologic Methodology and Data Objectives ........................................................................... B-1Hydrologic Design Data .............................................................................................................. B-1

Water Quality Design Data Analysis........................................................................................................ B-4Rainfall Data ................................................................................................................................ B-4Rainfall Data Analysis ................................................................................................................. B-4

Water Quality Storm................................................................................................................................. B-5Water Quality Design Depth........................................................................................................ B-6Water Quality Design Intensity ................................................................................................... B-6

Hydrologic Design Methods..................................................................................................................... B-7Water Quality Volume Determination......................................................................................... B-7Rational Method .......................................................................................................................... B-8SCS Unit Hydrograph................................................................................................................ B-10Continuous Simulation............................................................................................................... B-20

References............................................................................................................................................... B-20

Appendix B Attachment ........................................................................................................................ BA-1

Appendix C. Recommended Plant List..................................................................................................... C-1Turf Grass ................................................................................................................................................. C-1Grasses ...................................................................................................................................................... C-1Wetland, Non-Woody............................................................................................................................... C-1Trees and Shrubs, Woody......................................................................................................................... C-1


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ACKNOWLEDGMENTS

Text from the following documents has been used in the development of this manual without individualacknowledgment or footnotes:

Alaska Storm Water Guide, Alaska Department of Environmental Conservation, 2009

Alaska Highway Drainage Manual, Alaska Department of Transportation and PublicFacilities, 1995

Stormwater Management Manual for Western Washington, Washington State Department ofEcology, 2005

Stormwater Management Manual, City of Portland, 2008

Stormwater Management and Site Development Manual, Pierce County, Washington, 2008

Surface Water Design Manual, King County, Washington, 2009

Sources of figures, tables and photographs have been indentified.


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NOTE TO REVIEWERS

This version of the Stormwater Guidelines Manual has been written in a format to elicit discussion on the

manuals organization, thresholds for application of structures and practices, exemptions from

requirements and potential stormwater control structures. Some of the sections in this manual,

particularly the introduction, may be changed in tone and level of detail in the final versions of themanual. Notes to the reviewer have been added where specific further input is necessary.

The organization and presentation of the requirements can be changed in the process of developing the

manual. Whichever way the manual is ultimately organized, it will include the thresholds and concepts

presented here.

This manual has also been written in a format that assumes the manual will be adopted by reference in

the City and Borough of Juneau municipal code. An assessment of the existing code and recommended

code changes is discussed in a separate memorandum delivered to the City and Borough of Juneau on

December 30, 2008. That memorandum discusses the issue of adopting the manual by reference in the

municipal code.


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CHAPTER 1.INTRODUCTION

BACKGROUND AND OBJECTIVES FOR MANUALStormwater runoff is a natural occurrence, but the quantity and water quality of runoff can besignificantly affected by land development:

Most development activities replace permeable soils with impermeable roads, parking lotsand roofs, causing more stormwater to runoff rather than be absorbed into the soils on-site.

Stormwater picks up whatever pollutants are present on a site; for developed sites these arefrequently trash, oils and grease, fertilizers, pesticides, pet waste, and sediment. Stormwaterdrains typically discharge directly into a river, stream, lake or saltwater, so these pollutantsare introduced directly into natural water bodies with no treatment.

Many communities around the United States have strict stormwater requirements for development tomitigate stormwater impacts. Federal regulatory programs require these municipal stormwater programsfor all medium to large cities in urbanized areas or adjacent to sensitive water bodies. While the City andBorough of Juneau (CBJ) is not yet subject to these federal regulatory requirements, it likely will be in thefuture. Also, without stormwater requirements, and as development density increases in the CBJ,stormwater impacts will be noticeable. At that point it will be more difficult and expensive to correct thesituation. This Stormwater Guidance Manual is the first step in putting into place requirements that willprevent the creation of stormwater problems associated with new development.

Overview of Stormwater Management Measures

Stormwater management measures rely on best management practices(BMPs) to reduce stormwater impacts on areas surrounding a site of

development. BMPs take a variety of forms:

They may consist of installing structural features, such as wetponds, where stormwater flow is captured and detained to settleout pollutants.

They may involve operational procedures, such as storinghazardous materials in covered areas.

They may be associated with designing a development in a waythat minimizes the amount of runoff produced by preservingnatural vegetation and soils.

BMPs that have been shown to work best at specific sites and types of developments are identified inChapters 3 through 5 of this manual. These have been tailored to conditions in the Juneau area, asdiscussed below. In many cases, a single BMP will not be enough to adequately reduce pollution fromstormwater. Most developments will need a series of BMPs, including site design, source control, andtreatment control practices to meet stormwater requirements.

Best Management

Practices (BMPs) aremethods that have beendetermined to be the mosteffective, practical means ofpreventing or reducingpollution from stormwater.These methods can bestructural (e.g., devices,ponds) or non-structural(e.g., policies to reduceimperviousness).


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Objective

The objective of the CBJs Stormwater Guidance Manual is to address impacts on the environment fromstormwater runoff and to ensure that stormwater treatment and conveyance infrastructure is developed ina safe and efficient manner. The manual provides the following information:

Thresholds and exemptions for structural stormwater controls

Hydrologic and hydraulic design methods

Design, construction, and operational details for stormwater structures

Management practices that are required to prevent and reduce stormwater pollution fromcommercial, industrial and residential development.

Design and construction of stormwater conveyance structures

Submittal requirements for stormwater plan for local approval.

What This Manual Addresses

This manual addresses post-construction runoff, which is the stormwater produced from a developed sitesuch as a shopping plaza, gas station or housing development after construction has been completed.Appropriate stormwater management measures for these types of sites and others are described inChapters 3 through 6.

Development Size

Developments of all sizes have direct and cumulative impacts on waterquality and habitat. Regulating small developments, however, isexpensive and resources may be better allocated to regulating largedevelopments with more potential to cause pollution. This manualrequires water quantity controls for developments establishing morethan 2,000 square feet of impervious surface and requires water quality

treatment controls for developments establishing more than 5,000square feet of impervious surfaces that have the potential to transport pollutants to the environment. Developments below these thresholdsare encouraged to apply the stormwater control techniques and sourcecontrol practices to the maximum extent practical.

Larger developments with more potential to cause pollution shall berequired to develop more detailed reporting to assure that therequirements of this manual are met. A separate set of simplifiedreporting requirements is presented for smaller developments inAppendix A.

New Development, Redevelopment, and ExistingDevelopment

EPA regulations typically treat new development and redevelopmentthe same. This manual proposes that redevelopment projects have thesame requirements as new development projects in order to minimizethe impacts from new or replaced surfaces. To not discourageredevelopment projects, replaced surfaces are not required to be brought up to new stormwater standardsunless the noted cost or space thresholds are exceeded. As long as the replaced surfaces have similar

Why distinguish betweennew development,redevelopment, andexisting development?

Redevelopment is when analready-developed site

undergoes some sort ofchange. This may or maynot impact stormwater. Forexample, adding a newparking lot does impactstormwater, while interiorremodeling probably wontaffect stormwater. Thismanual includes specificcriteria to identify onlyredevelopment projects thatdo impact stormwater.

The manual does notaddress stormwater impactsfrom existing development,but the BMPs presentedcould certainly be used byowners of those sites.


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pollution-generating potential, the amount of pollutants discharged shouldnt be significantly different.However, if the redevelopment project scope is sufficiently large that required space criteria are exceeded,it is reasonable to require the replaced surfaces to be brought up to current stormwater standards. This isconsistent with other utility standards.

Maintenance activities such as a road surface overlay or reroof shall be exempt from the requirements for

construction of water quality and flow reduction BMPs. Utility projects where the trench surface isreplaced in kind shall also be exempt from requirements for construction of water quality and flowreduction BMPs.

Other Municipal Stormwater Needs

Municipal stormwater programs typically address three categories of stormwater management:

Post-construction stormwater management The subject of this manual, this is thepermanent management of stormwater originating from a developed site, and may includeboth water quantity and water quality controls.

Construction site stormwater managementStormwater runoff from construction sites can bea significant source of pollution. Erosion of bare earth, the coming and going of heavyequipment, and site clearing and grading all have the potential for big impacts on adjacentland and downstream water bodies. Construction stormwater management is not addressed inthis manual. However the hydrologic data and methodologies detailed in the manual can beused to help size and design temporary stormwater control structures. In addition many of the permanent water quality control structures described here can easily be modified to suitsediment control for construction sites.

Municipal operations and maintenance stormwater managementMany routine municipaloperations such as road and drainage work have potential stormwater impacts. Theseoperations are not the subject of this manual, but they may make use of the BMPs describedin Chapters 3 through 5.

GEOGRAPHIC CONSIDERATIONSThe Juneau area is unique in many ways, and a one size fits all strategy for stormwater management isnot appropriate. The steep topography of the coastal range makes development a challenge in uplandareas, leading to fairly high density urbanized development in the flatter lowland areas. Unfortunately, because these flatter areas are often near streams, lakes, wetlands, or Gastineau Channel, stormwatercontaminants may flow directly into these water bodies from developed sites.

The geographic regions described below and shown in Figure 1-1 warrant different levels of stormwaterregulation and controls. Stormwater considerations associated with each of these regions are describedbelow and in Chapters 3 through 6. Juneau has many drainages that, because they are steep or ephemeral,do not support resident or anadromous fish populations. Except for Montana Creek, this manual does notimpose additional protections for these streams.


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Figure1-1.C

BJGeographicRegionsandFeatures


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Montana Creek

Montana Creek is a productive fishery and scenic area that is highly valued by the community. The creekhas been identified as perhaps the highest priority creek for protection within Juneau. Most of the upperbasin is federally owned and not subject to modification or development. Some areas in the lower basinare in private property and there is concern that development will damage the creek ecosystem.Development in the watershed could lead to pollutants from stormwater affecting stream and riparianhabitat. In addition, development within the drainage area of Montana Creek tributaries may causechanges in the flow regime that may lead to habitat degradation both in the tributaries and the main stem.

This manual proposes that the Montana Creek drainage area have a higher level of protection:

Lower thresholds for water quality treatment (i.e. water quality treatment devices will berequired for smaller parking lots and roads)

Higher enforcement of source control requirements

Increased level of flow reduction: requirements/encouragement for approaches that reduce orslow runoff.


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Duck Creek and Jordan Creek

The lower portions of Duck Creek and JordanCreek are the only significant areas in Juneauthat are subject to riverine flooding that may becaused or exacerbated by increased runoff flowrates and volumes from development. Recentflood studies show that the 100-year floodplainsof Duck and Jordan Creeks cover largedeveloped areas in downstream portions of thecreeks drainage basins. Flooding here may be partly attributable to lack of flow control indevelopment in the basin. Flooding in theseareas may also be due to undersized culverts orbridges (i.e. Trout Street at Jordan Creek).

To ensure that future development does notincrease the flooding and drainage problems,

additional protections for the Duck and JordanCreek region will consist of the following:

Increased level of flow reduction:requirements/encouragement forapproaches that reduce or slow runoff.

Douglas Island

Douglas Island has small areas of commercial and dense residential development but otherwise is sparselydeveloped. The island is mostly drained by small creeks with small populations of anadromous fish.Douglas Island is perhaps the only area in Juneau where large-scale development can occur. WhetherDouglas Island will see large-scale development will depend on the local economy and construction of a

second bridge across the Gastineau Channel.

Large-scale future development in areas of Douglas Island has the potential to cause habitat degradationand flooding if flows from development are not controlled. This is particularly acute for steep areas suchas the east side of the island where residential development is increasing up the slope. Along with therunoff will come the potential for pollutants from stormwater to impact stream and riparian habitat. CBJhas the opportunity now to address these potential impacts proactively through identification of sensitiveareas, and implementation of stormwater BMPs to protect them.

Little information is currently available about sensitive streams and habitat areas on Douglas Island.Lacking information to the contrary, CBJ will operate under the assumption that all stream, riparian, andwetland areas are high-value habitat that should receive high-level protection. Similar to Montana Creek,

these protections will consist of the following:

Lower thresholds for water quality treatment (i.e. water quality treatment devices will berequired for smaller parking lots and roads)

Higher enforcement of source control requirements

Increased level of flow reduction: requirements/encouragement for approaches that reduce orslow runoff; flow detention using ponds or tanks.


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Direct Discharges to Large Water Bodies

Large water bodies such as Auke and Mendenhall Lakes, the Mendenhall River, Gold Creek, LemonCreek, and Gastineau Channel will be less affected by increased stormwater flow rates and volumes thansmaller streams. This manual does not require flow control for areas that drain directly to these waterbodies. Water quality BMPs will be required, along with adequate conveyance and outfall facilities tominimize erosion and other potential impacts.

Water quality for stormwater discharge to saltwater is governed by Alaskas marine water quality

standards.

Steep Hillsides

As development advances into steep hillside areas, stormwaterrunoff has the potential to be more hazardous than in flatterterrain. Steep slopes frequently have thin soils and can generatemore runoff than flatter areas. Runoff can be more difficult tocollect in a pipe system, it will have higher velocities, and itwill entrain more sediment and debris. To protect against theseproblems, this manual employs a lower threshold for requiringoff-site analysis of downstream effects in steep hillside areas.

Unpopulated Areas

The urbanized areas of Juneau (Downtown, Mendenhall Valleyand Douglas Island) cover only a small portion of the borough.Large developments in areas outside the urban servicesboundary (Figure 1-1), such as Taku Inlet, will be consideredon a case-by-case basis.


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APPLICABILITY TO STATE AND INTERJURISDICTIONAL PROJECTS

The applicability of the requirements of this manual to large construction projects led by othergovernment entities such as the Alaska Department of Transportation and Public Facilities (ADOT&PF)Juneau Access Road, Second Douglas Island Bridge and Airport Expansion has yet to be determined.Since these entities may have their own stormwater guidelines because of their statewide purview, there

will be a need to coordinate the two sets of requirements to determine appropriate BMPs.

RELATIONSHIP OF THIS MANUAL TO FEDERAL, STATE AND LOCALREGULATORY REQUIREMENTS

Few current federal or state regulations require changes to CBJ local stormwater regulation. The AlaskaDepartment of Environmental Conservation (ADEC) may require a permit for CBJ to dischargestormwater through a separate stormwater system following the U.S. Census in 2010. That Juneau is being proactive in addressing stormwater quality and quantity control issues may forestall state andfederal regulation. In addition, the regulatory climate is requiring stricter control on stormwater.Requirements for stricter stormwater regulation may be imposed on Juneau through other means such asthe Endangered Species Act.

Relevant federal, state and local stormwater regulations are discussed in Table 1-1. Additional detail isfound in ADECsAlaska Storm Water Guide.


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TABLE 1-1.SUMMARY OF FEDERAL, STATE AND LOCAL STORMWATER REGULATIONS

Program orPermit

Who isRegulated Description

Relation to StormwaterManagement and this Manual

National PollutantDischargeEliminationSystem (NPDES)MunicipalStormwaterPermit

EPA-designatedmedium-sizedcities

Requires development of a program that:regulates stormwater practices for newdevelopment, redevelopment and constructionsites; identifies and eliminates illicit dischargesto the stormwater system; provides publiceducation and involvement; and implements anoperations and maintenance program formunicipal operations.

CBJ is not currentlydesignated by EPA to requirea permit, however, it may berequired to obtain coverage in2012.

NPDES Generalpermit forStormwaterDischarges from

ConstructionActivity (alsoknown as theConstructionGeneral Permit(CGP))

Constructionoperators forsites withmore than

1 acre ofdisturbance

Requires operators to develop and implement aStormwater Pollution Prevention Plan(SWPPP) to define measures to be taken toreduce erosion and pollution during

construction. For guidance on developing aSWPPP and design of construction site BMPs,refer to the ADOT&PFsAlaska StormwaterPollution Prevention Plan Guide.

Hydrologic methodologies anddata in this may be used todesign temporary stormwatercontrol structures.

NPDES Multi-Sector GeneralPermit (MSGP)for stormwaterfrom industrialsites

EPA-designatedindustrialactivities

The MSGP requires permitted industrialfacilities, including those owned or operated

by municipalities, to develop a site-specificSWPPP to control stormwater pollution. InJuneau, this permit has been required foraffected gravel operations and mines.Satisfying the requirements of this manual willnot relieve the responsibility of obtaining anindustrial stormwater discharge permit.

Stormwater controls on thesepermitted industrial sitesshould benefit stormwaterquality coming off these sites.

While not the intended

audience for this manual,operators of these sites coulduse this manual as a resource.

United StatesArmy Corps ofEngineers 404Permit

Projectproponentswhere any sortof fill materialwill be addedto a regulatedwater body

Section 404 of the Clean Water Act authorizesthe Secretary of the Army to issue permits forthe discharge of dredged or fill material intowaters of the United States, includingnavigable waters and wetlands. The termdischarges of fill material means the additionof rock, sand, dirt, concrete, or other materialinto the waters of the United States incidental

to construction of any structure. A Section 404permit may require stormwater quality orquantity BMPs as mitigation.

In Juneau, the Corps of Engineers issuespermits for fill in Class A & B wetlands. CBJ(Wetland Review Board) issues a WetlandPermit for fill in Class C & D wetlands.

Not directly related tostormwater requirements inthis manual


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TABLE 1-1 (continued).SUMMARY OF FEDERAL, STATE AND LOCAL STORMWATER REGULATIONS

Program orPermit



Federal CleanWater Act Section401 WaterQualityCertification

Projectproponent forany projectthat mayimpact waterquality in aregulatedwater body

Requires any applicant for a federal permit forany activity that may affect the quality ofwaters of the United States to also obtain awater quality permit from the state in whichthe discharge originates or will originate. InAlaska, the ADEC issues water quality

permits.

Not directly related tostormwater requirements inthis manual

The Coastal ZoneActReauthorizationAmendments of

1990

Projectproponent forany projectthat may

impact waterquality in aregulatedwater body

This act requires that every state participatingin the federal Coastal Management Programuse erosion and sediment control managementmeasures. The Alaska Coastal Management

Program (ACMP) requires that estuaries,wetlands, tide flats, lagoons, rivers, streamsand lakes be managed to protect naturalvegetation, water quality, important fish andwildlife habitat, and natural water flow. TheACMP states that contractors for projectswithin the coastal zone must use all feasibleand prudent steps to maximize conformancewith this requirement. State and federalresource agencies that issue permits oftenrequire erosion control measures to ensure thata project will be consistent with the ACMP.

This manual could be used asa resource for stormwatermanagement BMPs that wouldfulfill the requirements of the

Coastal Zone Act.

EndangeredSpecies Act

Any activitiesthat mayinjure anendangeredspecies withinits criticalhabitat aresubject toreview andregulation.

There currently are no endangered species inthe Juneau area. In 1990, the eastern stock ofSteller sea lion was listed as threatened by the

National Marine Fisheries Service. TheEndangered Species Act can be used tointroduce increased stormwater regulationthrough federal programs such as the NationalFlood Insurance Program. Given the relativelysmall population and few other municipalitiesin the area, this may be unlikely.

Not currently an issue, butwould become a significantissue if a local species isdesignated as endangered.


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TABLE 1-1 (continued).SUMMARY OF FEDERAL, STATE AND LOCAL STORMWATER REGULATIONS

Program orPermit



Impaired WaterBody List (303(d)list) and WaterCleanup Plans(TMDLs)

State ofAlaska

Department ofEnvironmentalConservation,residents andbusinesseswithin eachwatershed

EPA requires the State of Alaska toperiodically prepare a list of all surface watersin the state for which beneficial usessuch asdrinking, recreation, aquatic habitat, andindustrial useare impaired by pollutants.Waters placed on the 303(d) list require the

preparation of total maximum daily load(TMDL) plans. TMDLs identify the maximumamount of a pollutant to be allowed to bereleased into a water body so as not to impairuses of the water, and allocate that amountamong various sources.

TMDLs for fecal coliform bacteria, debris,habitat modification and sediment have beendeveloped for several streams in Juneau(Duck, Jordan, Lemon, Vanderbilt andPederson Hill Creeks). These TMDLs allidentify stormwater runoff as a major source of

pollutants, and recommend that CBJ develop astormwater management program.

The stormwater managementmeasures proposed in thismanual will help address these

pollutants. In the future, morestringent requirements could

be imposed if current effortsfor cleanup are not determinedto be successful.

StormwaterDisposal Plans,AlaskaDepartment of

EnvironmentalConservation

Projectproponent

Modification of a stormwater treatment ordisposal system requires approval of ADEC

per 18 AAC 72.600

Should ADEC pursueenforcement of this regulation,water quality treatmentrequirements in this manual

may need to be changed tomatch requirements of AAC.

Alaska Statute41.14.870,Anadromous FishAct

Projectproponent

The Alaska Department of Fish and Game(ADF&G) regulates construction activities thatwill affect freshwater anadromous fish habitat.Any activity that will pollute or change thenatural flow or bed of a stream important forthe spawning, rearing, or migration ofanadromous fish must be approved byADF&G to ensure that the construction plansand specifications will protect fish and game.Often, the ADF&G permit requires an erosion

and sediment control plan.

BMP requirements in thismanual will providestormwater managementstandards for ADF&G staff touse in this review

CBJ Codes andOrdinances

Projectproponent

Local regulations affecting surface water,stormwater and water quality are found in CBJMunicipal Code Titles 19, 49 and 75.

Some local regulation isdiscussed in this manual.Compliance with this manualdoes not guarantee compliancewith all CBJ stormwaterregulations.


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CHAPTER 2.HOW TO USE THIS MANUAL

This manual is separated into four major areas that cover CBJs requirements for stormwater control:

Water quality

Water quantity

Conveyance

Stormwater site plan.

Each chapter details the geographic areas, thresholds and exemptions for the stormwater control structuresand practices that are required for development in Juneau. Details of design methodology, constructionand maintenance are provided in Chapters 3 through 6. Figure 2-1 is a flow chart summary of theapplication of the requirements. Additional stormwater requirements for land use and grading permits are

found in CBJs codes and ordinances.

Small Project

Development?

Water Quality

Water Quantity

Conveyance

Site Plan

Appendix ASmall Project

Stormwater Management

Yes

No

Chapter 3Stormwater Quality

Chapter 4Stormwater Quantity

Chapter 5Stormwater Conveyance

Chapter 6Stormwater Site Plan

Figure 2-1. How to Use This Manual


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CHAPTER 3.STORMWATER QUALITY

BACKGROUNDStormwater runoff from development can contain a wide variety of pollutants from many sources. Duringand after construction, sediment is transported to surface waters from developed sites at rates muchgreater than pre-development conditions. Runoff from industrial developments can include oils andgreases and metals. Runoff from residential areas can include nutrients and pesticides from landscapesand fecal coliform bacteria from pet wastes. Automobile traffic is a major source of oil and grease fromleaks, metals from brake pads and tires and hydrocarbons from exhaust fallout.

This chapter details the requirements, thresholds and application of two strategies for controlling pollutionin stormwater runoff (see Figure 3-1):

Source controlSource control BMPs are activities, prohibitions of practices, maintenance

procedures, and structural and/or managerial practices that prevent or reduce the potential forpollutants to come in contact with stormwater and be transported to the natural environment.Pollution source control measures can be separated into operational and structural measures.

Water quality treatmentWater quality treatment BMPs are structures used to treat orremove pollutants after they have come in contact with runoff. These BMPs use processessuch as settling, filtration and biological treatment to reduce pollutant levels. TreatmentBMPs target a wide range of stormwater pollutants, including sediment, oil and grease,metals and nutrients. This chapter details design and construction considerations for waterquality treatment structures, and outlines thresholds such as the level of sediment in astructure that calls for cleaning or the minimum infiltration rate for infiltration facilities

Preventing pollutants from contacting stormwater is a much more effective and cost-efficient method ofpollution control than removing pollutants from stormwater. Water quality treatment BMPs are expensiveto construct and maintain and are not 100-percent effective at removing pollutants. Many pollutants havebiological and physical impacts at very low concentrations that approach irreducible levels. Many waterquality treatment BMPs cannot feasibly remove pollutants below these concentrations.

THRESHOLDS AND EXEMPTIONS

Source Control

CBJ intends to implement pollution source control through education and encouraging commercial andresidential land owners to adopt source control practices. Should water quality conditions worsen or ifstate or federal regulation requires tighter controls, CBJ could require these practices for new construction

or as a condition of CBJ-issued permits or licenses.

Commercial landowners should follow the source control practices applicable to their industry.Residential land owners should follow residential pollution source control BMPs.


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Small Project Development

(>2,000 square feet

and 5,000 square feet of new or replacedpollution-generating impervious surfaces.

Options for basic stormwater control include: Vegetated filter strips

Biofiltration swales

Hydrodynamic separators

Filtration

Wet Ponds

Constructed Wetlands

Infiltration Basins

In addition, advanced stormwater quality treatment (oil control) is required for the following: High use parking lots, based on number of stalls (e.g., 30 stalls)

High use intersections (average daily traffic >15,000)

High use roads (average daily traffic >25,000)

Commercial facilities generating high loads of oils and greases.

Pollution Generating Impervious Surfaces (PGIS) areimpervious surfaces considered to be a significant sourceof pollutants in stormwater runoff. Such surfaces includethose which are subject to: vehicular use (roads andparking lots); certain industrial activities; or storage oferodible or leachable materials, wastes, or chemicals,and which receive direct rainfall or the run-on or blow-inof rainfall.


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3. STORMWATER QUALITY

3-3

The facility choices for oil control are intended to achieve the goals of no ongoing or recurring visiblesheen, and to have a 24-hour average Total Petroleum Hydrocarbon (TPH) concentration no greater than10 mg/l, and a maximum of 15 mg/l for a discrete sample (grab sample).

Options for oil control include:

Oil water separators

Sand Filtration

Catch Basin Inserts

Exemptions

Maintenance activities and utility projects that replace trench surface in kind shall be exempt from therequirement to construct stormwater quality control structures.


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3-4

SOURCE CONTROL

General BMPs for Commercial Development

The following operational source control BMPs should be implemented at applicable commercial andindustrial establishments.

Formation of a Pollution Prevention Team Assign one or more individuals to be responsible for stormwater pollution control.

Hold regular meetings to review the overall operation of the BMPs.

Establish responsibilities for inspections, operation and maintenance, and availability foremergency situations.

Train all team members in the operation, maintenance and inspections of BMPs, andreporting procedures.

Good Housekeeping Promptly contain and clean up solid and liquid pollutant leaks and spills, including oils,

solvents, fuels and dust from manufacturing operations on any exposed soil, vegetation or paved area. Use solid absorbents (e.g., clay and peat absorbents and rags) for cleanup ofliquid spills and leaks where practicable.

Sweep paved material-handling and storage areas regularly as needed, for the collection anddisposal of dust and debris that could contaminate stormwater. Do not hose down pollutantsfrom any area to the ground, storm drain, conveyance ditch, or receiving water unlessnecessary for dust control purposes to meet air quality regulations and unless the pollutantsare conveyed to a treatment system approved by the local jurisdiction.

Clean oil, debris, sludge, etc. from all BMP systems regularly, including catch basins,settling/detention basins, oil-water separators, boomed areas and conveyance systems, toprevent the contamination of stormwater.

Promptly repair or replace all substantially cracked or otherwise damaged paved secondarycontainment, high-intensity parking and any other drainage areas that are subject to pollutantmaterial leaks or spills.

Promptly repair or replace all leaking connections, pipes, hoses, valves, etc. that cancontaminate stormwater.

Recycle materials, such as oils, solvents and wood waste, to the maximum extent practicable.

Preventive Maintenance Prevent the discharge of unpermitted liquid or solid wastes, process wastewater and sewage

to ground or surface water, or to storm drains that discharge to surface water or to the ground.

Do not connect floor drains in potential pollutant source areas to storm drains, surface wateror the ground.

Conduct all cleaning, steam cleaning or pressure washing of oily equipment or containersinside a building or on an impervious contained area, such as a concrete pad. Directcontaminated stormwater from such areas to a sanitary sewer where allowed by the localsewer authority or to other approved treatment.

Do not pave over contaminated soil unless it has been determined that groundwater has notbeen and will not be contaminated by the soil.


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Construct impervious areas that are compatible with the materials handled. Portland cementconcrete, asphalt, or equivalent material may be considered.

Use drip pans to collect leaks and spills from industrial/ commercial equipment such ascranes at ship/boat building and repair facilities, log stackers, industrial parts, and trucks andother vehicles that are stored outside. Empty drip pans immediately after a spill or leak is

collected in an uncovered area. At industrial and commercial facilities, drain oil and fuel

filters before disposal. Discard empty oil and fuel filters, oilyrags and other oily solid waste into appropriately closed and properly labeled containers, and in compliance with theUniform Fire Code.

For the storage of liquids, use containers, such as steel and plastic drums, that are rigid and durable, resistant tocorrosion due to weather and fluid content, non-absorbent,water tight, rodent-proof, and equipped with a close-fittingcover.

For the temporary storage of solid wastes contaminated with liquids or other potentialpollutant materials, use dumpsters, garbage cans, drums and comparable containers that aredurable, corrosion-resistant, non-absorbent, non-leaking and equipped with either a solidcover or screen cover to prevent littering. If covered with a screen, the container must bestored under a lean-to or equivalent structure.

Where feasible, store potential stormwater pollutant materials inside a building or under acover and/or containment.

Minimize use of toxic cleaning solvents, such as chlorinated solvents, and other toxicchemicals.

Use environmentally safer raw materials, products, additives, etc., such as substitutes for zincused in rubber production.

Stencil warning signs at stormwater catch basins and drains, e.g., Dump no waste.

Where exposed to stormwater, use containers, piping, tubing, pumps, fittings, and valves thatare appropriate for their intended use and for the contained liquid.

Spill Prevention and Cleanup If pollutant materials are stored on-site, have spill

containment and cleanup kits readily accessible.Place and maintain spill kits at outside areas wherethere is a potential for fluid spills. These kits should be stocked as appropriate for the materials beinghandled and the size of the potential spill.

If a spill has reached or may reach a sanitary or astorm sewer, groundwater or surface water, notifythe local sewer authority immediately. Notificationmust comply with and federal spill reportingrequirements.

Do not flush absorbent materials or other spill cleanup materials to a storm drain. Collect thecontaminated absorbent material as a solid and place in appropriate disposal containers.

Note: Evidence of stormwatercontamination can include thepresence of visible sheen, coloror turbidity in the runoff, orpresent or historical operationalproblems at the facility. SimplepH measurements with litmus orpH paper can be used to test forstormwater contamination inareas subject to acid or alkalinecontamination.

Note: Recommended items for spillkits include salvage drums orcontainers, such as high densitypolyethylene, polypropylene orpolyethylene sheet-lined steel;polyethylene or equivalent disposal

bags; an emergency responseguidebook; safetygloves/clothes/equipment; shovels orother soil removal equipment; and oilcontainment booms and absorbentpads; all stored in an imperviouscontainer.


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3-6

Employee Training

Train all employees who work in pollutant source areas in identifying pollutant sources and inunderstanding pollutant control measures, spill response procedures, and environmentally acceptablematerial handling practicesparticularly those related to vehicle/equipment liquids such as fuels, andvehicle/equipment cleaning.

Inspections

Conduct visual inspections quarterly during storm events to achieve the following:

Verify that the descriptions of the pollutant sources identified by the pollution preventionteam are accurate.

Verify that the stormwater pollutant controls (BMPs) being implemented are adequate.

Update the site map to reflect current conditions.

Include observations of the presence of floating materials, suspended solids, oil and grease,discoloration, turbidity and odor in stormwater discharges, in outside vehiclemaintenance/repair, and in liquid handling and storage areas. In areas where acid or alkaline

materials are handled or stored, use a simple litmus or pH paper to identify the types ofstormwater contaminants.

Conduct at least one dry season inspection each year.

Determine whether there are unpermitted non-stormwater discharges to storm drains orreceiving waters, such as process wastewater and vehicle/equipment washwater, and eithereliminate or obtain a permit for such a discharge.

Record Keeping

Retain the following reports for three years:

Visual inspection reports, which should include: the scope of the inspection, the personnel

conducting the inspection, the dates of the inspection, major observations regardingstormwater (performance of the BMPs, etc.), and actions taken to correct BMP inadequacies.

Reports on spills of oil or hazardous substances in greater than Reportable Quantities (Codeof Federal Regulations Title 40 Parts 302.4 and 117), including oil, gasoline or diesel fuelthat causes a violation of water quality standards, or, that causes a film or sheen upon ordiscoloration of the surface waters or adjoining shorelines or causes a sludge or emulsion tobe deposited beneath the surface of the water or upon adjoining shorelines.


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3-7

Site-Specific BMPs for Commercial Development

Fueling at Dedicated Stations

Description of Pollutant Sources

A fueling station is a facility dedicated to the transfer of fuels from a stationary pumping station to mobile

vehicles or equipment. It includes above- or under-ground fuel storage facilities. In addition to generalservice gas stations, fueling may occur at 24-hour convenience stores, construction sites, warehouses, carwashes, manufacturing establishments, port facilities, and businesses with fleet vehicles. Typically,stormwater contamination at fueling stations is caused by leaks or spills of fuels, lube oils, radiatorcoolants and vehicle wash water.

Pollutant Control Approach

New or substantially remodeled* fueling stations must beconstructed on an impervious concrete pad under a roof to keepout rainfall and stormwater run-on. A treatment BMP must beused for contaminated stormwater and wastewaters in the fuelingcontainment area.

Operational BMPs for New or Substantially Remodeled Fueling Stations Prepare an emergency spill response and cleanup plan and have designated trained staff

available on site or on call at all times to promptly and properly implement that plan andimmediately cleanup all spills. Keep suitable cleanup materials, such as dry adsorbentmaterials, on site to allow prompt cleanup of a spill.

Train employees in the proper use of fuel dispensers. Post signs in accordance with theUniform Fire Code (UFC). Post No Topping Off signs (topping off gas tanks causesspillage and vents gas fumes to the air). Make sure that the automatic shutoff on the fuelnozzle is functioning properly.

The person conducting the fuel transfer must be present at the fueling pump during fueltransfer, particularly at unattended or self-serve stations.

Keep drained oil filters in a suitable container or drum.

Structural Source Control BMPs for New or Substantially Remodeled Fueling Stations Design the fueling island to control spills (dead-end sump or spill control separator in

compliance with the UFC), and to treat collected stormwater and/or wastewater to requiredlevels. Slope the concrete containment pad around the fueling island toward trench drains,catch basins or a dead-end sump. The slope of the drains shall not be less than 1 percent(UFC Section 7901.8). Drains to treatment shall have a shutoff valve, which must be closedin the event of a spill. The spill control sump must be sized in compliance with UFC Section7901.8; or

Design the fueling island as a spill containment pad with a sill or berm raised to a minimumof 4 inches (UFC Section 7901.8) to prevent the runoff of spilled liquids and to prevent run-on of stormwater from the surrounding area. Raised sills are not required at the open-gratetrenches that connect to an approved drainage-control system.

The fueling pad must be paved with Portland cement concrete or equivalent. Asphalt is notconsidered an equivalent material.

* Substantial remodeling includesreplacing the canopy or relocatingor adding one or more fueldispensers in a way that modifiesthe paving in the fueling area.


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The fueling island must have a roof or canopy to prevent the direct entry of precipitation ontothe spill containment pad. The roof or canopy should, at a minimum, cover the spillcontainment pad (within the grade break or fuel dispensing area) and preferably extendseveral additional feet to reduce the introduction of windblown rain. Connect all roof drainsto storm drains outside the fueling containment area.

Stormwater collected on the fuel island containment pad must be conveyed to a sanitarysewer system, if approved by the sanitary authority; or to an approved treatment system suchas an oil-water separator and a basic treatment BMP. Discharges from treatment systems tostorm drains or surface water or to the ground must not display ongoing or recurring visiblesheen and must not contain a significant amount of oil and grease.

Alternatively, stormwater collected on the fuel island containment pad may be collected andheld for proper off site disposal.

Conveyance of any fuel-contaminated stormwater to a sanitary sewer must be approved bythe local sewer authority and must comply with pretreatment regulations. These regulationsprohibit discharges that could cause fire or explosion. An explosive or flammable mixture isdefined under state and federal pretreatment regulations, based on a flash point determinationof the mixture. If contaminated stormwater is determined not to be explosive, then it could beconveyed to a sanitary sewer system.

Transfer the fuel from delivery tank trucks to the fuel storage tank in impervious containedareas and ensure that appropriate overflow protection is used. Alternatively, cover nearbystorm drains during the filling process and use drip pans under all hose connections.


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3-9

Building, Repair, and Maintenance of Boats and Ships


Most marinas and boatyards are located on or adjacent to coastal waters, lakes and rivers, and theiractivities can contribute significant pollution directly to these water bodies. The following BMPs apply toonshore repair activities, mobile operations, and on-water fueling and repair operations. These can pollute

stormwater and surface water with toxic organic compounds and oils/greases, heavy metals, suspendedsolids, nutrients and abnormal pH.

The toxic organic compounds most commonly associated with activities at marinas and boatyards arehydrocarbons and solvents. Hydrocarbons include lubrication oil, gasoline, fuel oil and exhaust residues.Components of gasoline, diesel fuel, kerosene and solvents can be acutely toxic. Solvents such astetrachloroethylene, tetrachloroethane, trichloroethylene, trichloroethane, and methylene chloride are usedas degreasing agents and in varnishes, paint removers and lacquers. Many solvents are knowncarcinogens.

Heavy metals are found in paint particles, metal shavings, engine oils, bilge water and runoff frommaintenance and repair areas and include lead, mercury, copper, nickel, cadmium, zinc, chromium, and

arsenic. Metals, such as chromated copper arsenate (CCA) are in wood preservatives commonly used indock and pier construction. Metals generally do not break down into less harmful chemicals and tend toaccumulate where they are released into the environment.

Soil may enter a water body during construction and by stormwater runoff. Operating boats in shallowwaters can scour the bottom and re-suspend bottom sediment, as well as cut off or uproot plants.Sediments are also stirred up during dredging operations. Sediments can affect a water body in severalways:

By smothering bottom-dwelling plants and animals

By decreasing clarity, which may reduce the amount of available light that plants andphytoplankton need to grow, as well as affect the ability of animals to find food

By clogging fish gills

By increasing sediment oxygen demand, resulting in the depletion of dissolved oxygen

By attaching to contaminants, such as heavy metals and hydrocarbons.

Nutrients, particularly nitrogen and phosphorus, are essential to plant growth. However, in elevatedconcentrations, they stimulate nuisance plant growth in the form of algal blooms or excessive growth ofweeds. When excessive plant growth dies and decays, dissolved oxygen concentrations may becomedepleted and kill fish and other animals. Algal blooms can reduce light penetration and harm beneficialplants. Also, excessive growth of tiny plants attached to the blades of larger plants can harm the growth ofthe larger plant. Weed-like plants tend to out-compete normal plants and may smother animals. Likeexcessive nutrients, abnormal pH can harm plant growth and animal life.


Apply good housekeeping and preventive maintenance and contain BMPs in and around work areas.

Operational BMPs

The following BMPs are required for operations engaged in boat building, mooring, maintenance andrepair:


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Move maintenance and repair activities onshore if possible. This action reduces some of thepotential for direct pollution of water bodies.

Shelter any blasting and spray painting activities by hanging wind blocking tarps to preventdust and overspray from painting.

Use ground cloths or drip pans for collection of strips and spills in painting, maintenance,

repair and finishing activities.

Collect bilge and ballast water that has an oily sheen on the surface. Properly dispose of itrather than dumping it in surface waters or on land.

Employ a bilge pump-out service or use oil absorbent pads to capture the oil in bilge waterbefore pumping. If pads are used, they must be recycled or properly disposed of.

To avoid spilling directly in surface water bodies, perform paint and solvent mixing, fuelmixing and similar handling of liquids on-shore. Clean up spills immediately. Do not washspills to a storm drain or surface water.

Collect and properly dispose of wash water from washing painted boat hulls. Consider takingthe boat to a local boat yard that is equipped to collect and treat the wash water. Never

dispose of wash water containing soap or other chemicals to storm drains or surface waters.This practice is acceptable if washing a boat with only water.

The following BMPs are optional unless the above minimum BMPs fail to provide adequate sourcecontrol:

Boat construction and structural repair activities should be covered.

A tarp should be placed above the water surface underneath the work area on boats or docksto collect spills, drips, paint chips and loose solids when work is performed over water.

All used oil and oil filters should be recycled. Most marinas now offer used oil recyclingservices.

No soaps or detergents of any kind should be used to wash the topsides of hulls of boatswhere the wash water will enter surface waters.

Use sanders that have dust containment bags.

Required Routine Maintenance Store and maintain appropriate spill cleanup materials in a clearly marked location. Ensure

that employees are familiar with the sites spill control plan and/or proper spill cleanupprocedures.

Sweep maintenance yard areas, docks, and boat ramps as needed to collect sandblastingmaterial, paint chips, oils and other loose debris. These collected materials are to be properlydisposed of. Do not hose down the area to a storm drain or to the water.


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3-11

Deicing and Anti-Icing Operations; Airports and Streets


This section applies to deicing and anti-icing operations to control ice and snow on streets, highways,airport runways and aircraft. Deicers commonly used on highways and streets include sand, calciummagnesium acetate, calcium chloride, magnesium chloride, sodium chloride, urea, and potassium acetate.

Deicers used on aircraft are typically ethylene glycol and propylene glycol. These deicing and anti-icingcompounds become pollutants when they enter storm drains or surface water after application. Leaks andspills of these chemicals can also occur during handling and storage. BMPs for aircraft deicers and anti-icers must be consistent with aviation safety and the operational needs of the aircraft operator.

BMPs for Aircraft

The following BMPs are required for operations that perform deicing and/or anti-icing operations onaircraft:

Conduct aircraft deicing or anti-icing applications in impervious containment areas. Collectaircraft deicer or anti-icer spent chemicals, such as glycol, draining from the aircraft indeicing or anti-icing application areas and convey to a sanitary sewer, treatment or other

approved disposal or recovery method. Divert deicing runoff from paved gate areas toappropriate collection areas or conveyances for proper treatment or disposal.

Do not allow spent deicer or anti-icer chemicals, or stormwater contaminated with aircraftdeicer or anti-icer, to be discharged from application areas, including gate areas, to surfacewater or ground water, directly or indirectly.

Transfer deicing and anti-icing chemicals on an impervious containment pad, or equivalentspill/leak containment area, and store in secondary containment areas.


Establish a centralized aircraft de/anti-icing facility or, centralize activities in designatedareas of the tarmac equipped with separate collection drains for the spent deicer liquids.

Consider installing an aircraft de/anti-icing chemical recovery system, or contract with achemical recycler.

BMPs for Airport Runways/Taxiways

The following BMPs are required for operations that are engaged in airport runway/taxiway deicing andanti-icing:

Avoid excessive application of all de/anti-icing chemicals.

Store and transfer de/anti-icing materials on an impervious containment pad or an equivalentcontainment area and/or under cover.

Do not hose down the area to a storm drain, a conveyance to a storm drain, or a receivingwater.

Choose one or more of the following options for stockpiles greater than 5 cubic yards of erodible or watersoluble materials:

Store in a building or a paved and bermed covered area.

Place temporary plastic sheeting over the material.


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Pave the area and install a stormwater drainage system. Place curbs or berms along theperimeter of the area to prevent the run-off of uncontaminated stormwater and to collect andconvey drainage to treatment. Slope the paved area in a manner that minimizes the contact between stormwater (e.g., pooling) and leachable materials in compost, logs, bark, woodchips, etc.

For large stockpiles that cannot be covered, implement containment practices at the perimeterof the site and at any catch basins as needed to prevent erosion and discharge of thestockpiled material offsite or to a storm drain. Ensure that contaminated stormwater is notdischarged directly to catch basins without being conveyed through a treatment BMP.


Include limits on toxic materials and phosphorous in the specifications for de/anti-icers,where applicable.

Consider using anti-icing materials rather than deicers if it will result in less adverseenvironmental impact.

Select cost-effective de/anti-icers that cause the least adverse environmental impact.

BMPs for Streets/Highways

The following BMPs are required for operations that are engaged in street/highway deicing and anti-icing:

Select de/anti-icers that cause the least adverse environmental impact. Apply only as neededusing minimum quantities.

Where feasible and practical, use roadway deicers, such as calcium magnesium acetate,potassium acetate, or similar materials, as they cause less adverse environmental impact thanurea and sodium chloride.

Store and transfer de/anti-icing materials on an impervious containment as stated in

Applicable BMPs for Airport Runways/Taxiways. Sweep/clean up accumulated de/anti-icing materials and grit from roads as soon as possible

after the road surface clears.


Intensify roadway cleaning in early spring to help remove particulates from road surfaces.

Include limits on toxic metals in the specifications for de/anti-icers.


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Maintenance of Roadside Ditches


Common road debris including eroded soil, oils, vegetative particles and heavy metals can be a source ofstormwater pollutants.


Roadside ditches should be maintained to preserve the condition and capacity for which they wereoriginally constructed, and to minimize bare or thinly vegetated ground surfaces. Maintenance practicesshould provide for erosion and sediment control.

Operational BMPs for Maintenance of Roadside Ditches

The following BMPs are required for all activities pertaining to roadside ditches:

Inspect roadside ditches regularly to identify sediment accumulations and localized erosion.

Clean ditches on a regular basis. Ditches should be kept free of rubbish and debris.

Vegetation in ditches often prevents erosion and cleanses runoff waters. Remove vegetationonly when flow is blocked or excess sediments have accumulated. Conduct ditchmaintenance (seeding, fertilizer application, harvesting) in late spring and/or early fall, wherepossible. This allows vegetative cover to be re-established by the next wet season, therebyminimizing erosion of the ditch as well as making the ditch effective as a biofilter.

In the area between the edge of the pavement and the bottom of the ditch, commonly knownas the bare earth zone, use grass vegetation wherever possible. Vegetation should beestablished from the edge of the pavement if possible, or at least from the top of the slope ofthe ditch.

Ditch cleanings are not to be left on roadway surfaces. Sweep dirt and debris remaining onthe pavement at the completion of ditch cleaning operations.

Roadside ditch cleanings not contaminated by spills or other releases and not associated witha stormwater treatment system such as a biofiltration swale may be screened to remove litterand separated into soil and vegetative matter (leaves, grass, branches, needles, etc.). The soilfraction may be handled as clean soils and the vegetative matter can be composted ordisposed of in a municipal waste landfill.

Roadside ditch cleanings contaminated by spills or other releases known or suspected tocontain dangerous waste must be handled following CBJ regulations unless testingdetermines it is not dangerous waste.

Examine culverts on a regular basis for scour or sedimentation at the inlet and outlet, andrepair as necessary. Give priority to culverts conveying perennial or salmon-bearing streamsand culverts near streams in areas of high sediment load, such as those near subdivisions

during construction.

The following BMP is optional unless the above minimum BMPs fail to provide adequate source control:

Install biofiltration swales and filter strips to treat roadside runoff wherever practical and useengineered topsoils wherever necessary to maintain adequate vegetation. These systems canimprove infiltration and stormwater pollutant control upstream of roadside ditches.


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Maintenance and Repair of Vehicles and Equipment


Pollutant sources include parts/vehicle cleaning, spills/leaks of fuel and other liquids, replacement ofliquids, outdoor storage of batteries/liquids/parts, and vehicle parking.


Good control of leaks and spills of fluids using good housekeeping, and cover and containment BMPs.

Operational BMPs for Maintenance and Repair of Vehicles and Equipment

The following BMPs are required for all activities pertaining to maintenance and repair of vehicles andequipment:

Inspect for leaks all incoming vehicles, parts and equipment stored temporarily outside.

Use drip pans or containers under parts or vehicles that drip or that are likely to drip liquids,such as during dismantling of liquid-containing parts of removal or transfer of liquids.

Remove batteries and liquids from vehicles and equipment in designated areas designed to prevent stormwater contamination. Store cracked batteries in a covered non-leakingsecondary equipment system.

Empty oil and fuel filters before disposal of waste oil and fuel.

Do not pour/convey washwater, liquid waste, or other pollutants into storm drains or tosurface water. Check with the local sanitary sewer authority for approval to convey to asanitary sewer.

Do not connect maintenance and repair shop floor drains to storm drains or to surface water.To allow for snowmelt during the winter, a drainage trench with a sump for particulatecollection can be installed and used only for draining the snowmelt and not for dischargingany vehicular or shop pollutants.


Consider storing damaged vehicles inside a building or other covered containment until allliquids are removed. Remove liquids from vehicles retired for scrap.

Clean parts with aqueous detergent based solutions or non-chlorinated solvents such askerosene or high flash mineral spirits, and/or use wire brushing or sand blasting whenever practicable. Avoid using toxic liquid cleaners such as methylene chloride, 1,1,1-trichloroethane, trichloroethylene or similar chlorinated solvents. Choose cleaning agents thatcan be recycled.

Inspect all BMPs regularly, particularly after a significant storm. Identify and correct

deficiencies to ensure that the BMPs are functioning as intended.

Avoid hosing down work areas. Use dry methods for cleaning leaked fluids.

Recycle grasses, used oil, oil filters, antifreeze, cleaning solutions, automotive batteries,hydraulic fluids, transmission fluids, and engine oils.

Do not mix dissimilar or incompatible waste liquids stored for recycling.


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Structural Source Control BMPs Conduct all maintenance and repair of vehicles and equipment in a building or other covered

impervious containment area that is sloped to prevent run-on of uncontaminated stormwaterand runoff of contaminated stormwater.

The maintenance of refrigeration engines in refrigerated trailers may be conducted in a

parking area with due caution to avoid the release of engine or refrigeration fluids to stormdrains or surface waters.

Park large mobile equipment, such as log stackers, in a designated contained area.

Treatment

Contaminated stormwater runoff from vehicle staging and maintenance areas must be conveyed to asanitary sewer, if allowed by the local sewer authority, or to an oil-water separator, applicable filter, orother equivalent oil treatment system.


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Landscaping and Lawn/Vegetation Management


This activity encompasses all aspects of landscaping and vegetationmanagement, from small-scale yard maintenance to large-scale commerciallandscaping businesses and vegetation management programs. It includes

vegetation removal, pesticide and herbicide application, fertilizer application,watering, clearing, grading, and other practices. These may contaminatestormwater runoff with the following pollutants: pesticides and other toxic organic compounds; metals,such as arsenic, cadmium, chromium, copper, lead and zinc; oils; suspended solids; and coliform bacteria.

Fertilizer runoff adds nutrients to water, causing excessive plant and algae growth. When too muchgrowth occurs, the dead and/or dying plant material in the water can take the oxygen out of the water andsuffocate all other life in the water.

Pollutant Control Approach Control fertilizer and pesticide applications, soil erosion, and site debris to prevent

contamination of stormwater.

Consider using the Integrated Pest Management (IPM) approach for pest control, and usepesticides only as a last resort. IPM is an effective pest management approach that uses anarray of methods to manage pest damage with the least possible hazard to people and theenvironment. Using IPM practices can significantly reduce or eliminate the needs forpesticides.

Operational BMPs for Landscaping

The following BMPs or equivalent measures, methods or practices are required in landscaping activities:

Install engineered soil/landscape systems to improve infiltration and the regulation ofstormwater in landscaped areas.

Do not dispose of collected vegetation into waterways orstorm drainage systems.

Conduct mulch-mowing whenever possible or dispose ofgrass clippings, leaves, sticks, or other collectivevegetation by composting, if feasible.

The following BMPs are optional unless the minimum requiredBMPs fail to provide adequate source control:

Use mulch or other erosion control measures when soilsare exposed for more than one week during the dry season or two days during the rainyseason.

If oil or other chemicals are handled, store and maintain appropriate oil and chemical spillcleanup materials in readily accessible locations. Ensure that employees are familiar withproper spill cleanup procedures.

Till fertilizers into the soil rather than dumping or broadcasting onto the surface. Determinethe proper fertilizer application for the types of soil and vegetation encountered.

Till a topsoil mix or composted organic material into the soil to create a well-mixed transitionlayer that encourages deeper root systems and drought-resistant plants.

Note: The termpesticide includesinsecticides, herbicides,

fungicides, etc.

Note: Installing an amended soil/landscapesystem can preserve both the plant systemand the soil system more effectively. Thistype of approach provides a soil/landscapesystem with adequate depth, permeability,and organic matter to sustain itself andcontinue working as an effectivestormwater infiltration system and a nutrientcycle.


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Use manual

Alaska; Stormwater Guidance Manual - Juneau

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