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Stormwater Pollution Prevention Plan
For
Younker Nissan
Prepared For
Northwest Regional Office
3190 - 160th Avenue SE
Bellevue, WA 98008-5452
425-649-7000
Owner Developer Operator/Contractor
Younker Nissan Younker Nissan Younker Nissan
3820 E. Valley Hwy. So. 3820 E. Valley Hwy. So. 3820 E. Valley Hwy. So.
� Renton, WA 98055 Renton, WA 98055 Renton, WA 98055
I
,
�_ Project Site Location
! Renton, WA
� Certified Erosion and Sediment Control Lead
Jeff Brown, P.E.
� (425) 827-5874
SWPPP Prepared By
Peterson Consulting Engineers
� 4010 Lake Washington Blvd. NE, Suite 300
Kirkland, WA 98033
(425) 827-5874
Jeff Brown, P.E., Project Manager ,� - ,
t��` �,,,� - �
SWPPP Preparation Date , Y ���,�� ' \ �`�
May 9, 2007 � '�
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Approximate Project Construction Dates �
July 2007 �',.��
March 2008 �a �\.: .� a
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IC ontents
I1.0 Introduction...............................................................................................................................5
2.0 Site Description........................................................................................................................7
� 2.1 Existing Conditions...........................................................................................................7
2.2 Proposed Construction Activities......................................................................................7
� 3.0 Construction Stormwater BMPs...............................................................................................9
3.1 The 12 BMP Elements.......................................................................................................9
3.1.1 Element#1 —Mark Clearing Limits ................................................................9
I3.1.2 Element#2—Establish Construction Access...................................................9
3.1.3 Element#3 —Control Flow Rates..................................................................10
3.1.4 Element#4—Install Sediment Controls ........................................................10
I3.1.5 Element#5 — Stabilize Soils..........................................................................11
3.1.6 Element#6—Protect Slopes..........................................................................12
( 3.1.7 Element#7—Protect Drain Inlets..................................................................12
3.1.8 Element#8—Stabilize Channels and Outlets................................................13
3.1.9 Element#9—Control Pollutants....................................................................13
I 3.1.10 Element#10—Control Dewatering...............................................................15
3.1.11 Element#11 —Maintain BMPs......................................................................15
3.1.12 Element#12—Manage the Project................................................................16
� 3.2 Site Specific BMPs..........................................................................................................18
3.3 Additional Advanced BMPs............................................................................................18
4.0 Construction Phasing and BMP Implementation...................................................................19
1 5.0 Pollution Prevention Team ...19
...................................................................................................
� 5.1 Roles and Responsibilities...............................................................................................19
5.2 Team Members. .20
6.0 Site Inspections and Monitoring.............................................................................................21
� 6.1 Site Inspection.................................................................................................................21
6.1.1 Site Inspection Frequency..............................................................................21
I 6.1.2 Site Inspection Documentation......................................................................22
6.2 Stormwater Quality Monitoring............... 22
62.1 Turbidity Sampling........................................................................................22
I7.0 Reporting and Recordkeeping................................................................................................25
7.1 Recordkeeping.................................................................................................................25
� 7.1.1 Site Log Book................................................................................................25
7.1.2 Records Retention..........................................................................................25
7.1.3 Access to Plans and Records..........................................................................25
� 7.1.4 Updating the SWPPP.....................................................................................25
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Stormwater Pollution Prevention Plan
several appendices that include stormwater related reference materials. The topics presented in
the each of the main sections are:
■ Section 1 — INTRODUCTION. This section provides a suinmary
description of the project, and the organization of the SWPPP document.
■ Section 2—SITE DESCRIPTION. This section provides a detailed
i ' description of the existing site conditions, proposed construction activities,
and calculated stormwater flow rates for existing conditions and post—
construction conditions.
■ Section 3 —CONSTRUCTION BMPs. This section provides a detailed
description of the BMPs to be implemented based on the 12 required
elements of the SWPPP (SWMMWW 2005).
■ Section 4—CONSTRUCTION PHASING AND BMP
IMPLEMENTATION. 'This section provides a description of the timing
of the BMP implementation in relation to the project schedule.
■ Section 5 —POLLUTION PREVENTION TEAM. This section identifies
the appropriate contact names (emergency and non-emergency),
monitoring personnel, and the onsite temporary erosion and sedimentation
control inspector
■ Section 6-1NSPECTION AND MONITORING. This section provides a
description of the inspection and monitoring requirements such as the
parameters of concern to be monitored, sample locations, sample
frequencies, and sampling methods for all stormwater discharge locations
from the site.
■ Section 7—RECORDKEEPING. This section describes the requirements I
for documentation of the BMP implementation, site inspections,
monitoring results, and changes to the implementation of certain BMPs
due to site factors experienced during construction.
- Supporting documentation and standard forms are provided in the following Appendices:
Appendix A—Site Plans
Appendix B —Construction BMPs
Appendix C—Alternative Construction BMPs
Appendix D—General Permit
Appendix E—Site Log and Inspection Forms
Appendix F—Engineering Calculations
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Stormwater Pollution Prevention Plan
2.0 Site Description
2.1 Existing Conditions
The 4.51 acre site is very flat and the drainage patterns within the site are not easily discerned.
, The existing site drainage eventually sheet flows to the south across the site and is collected in a
shallow swale along the south property line. The swale drains gently to the west and exits the
site at the southwest corner of the property. The swale continues to the west along the railroad
right-of-way and discharges into a catch basin approximately 380 feet west of the site. Flow
continues to the west through a series of pipes and catch basins and discharges into the 60 inch
storm drain running north-south under Lind Avenue Southwest (approx. 750 feet downstream of
the site). Flow continues north in the 60 inch storm drain to the intersection of Lind Avenue
Southwest and SW 34�' Street. Flow continues west in the SW 34th Street storm drain system
and discharges into Springbrook Creek, approximately 2400 feet downstream of the site.
Springbrook Creek flows to the north, crosses under Interstate 405, and discharges into the Green
River, approximately 3.0 miles downstream of the site. The Green River enters the Duwamish
River, continues to flow north and is discharged into Elliott Bay.
Soils on the western portion of the site are mapped as Snohomish silt loam. Soils on the eastern
portion of the site are mapped as Tukwila muck.
The site is located in an area of susceptibility to liquefaction during seismic events,but is
otherwise not located in or near known critical areas.
2.2 Proposed Construction Activities
The proposed development activities will include TESC installation, excavation, grading,
utilities,paving, sidewalks, landscaping and construction of a 2-story building with approx.
23,800 sq. ft. footprint.
The source of storm water runoff will include the roof of the new building, parking areas and
drive aisles. Storm water runoff will be collected in a network of catch basins and routed to a
water quality/detention system. Discharge from the detention system will be conveyed to the
storm drain main in East Valley Road. The flow in the main will be conveyed north along East
Valley Road and discharged into a drainage way at SW 23� Street. The drainage way conveys
flow to the west and discharges into Springbrook Creek approximately 2400 feet downstream of
the site.
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Stormwafer Pollution Prevention Plan
A temporary erosion and sediment control plan consistent with City of Renton regulations will
be utilized for this project. The schedule and phasing of BMPs during construction is provided
in Section 4.0.
Stormwater runoff volumes were calculated using the Western Washington Hydrology Model
(WWHM). The temporary sedimentation pond that will be used during construction was
designed using the 2-year storm event since construction will not occur over a long time-frame
(approximately one year).
The following summarizes details regarding site areas:
■ Total site area: 4.51 acres
■ Percent impervious area before construction: 0 %
■ Percent impervious area after construction: 75 %
■ Disturbed area during construction: 4.5 acres
■ 2-year stormwater runoff peak flow prior to construction
(existing): 0.11 cfs
■ 10-year stormwater runoff peak flow prior to construction
(existing): 0.20 cfs
■ 2-year stormwater runoff peak flow after construction: 0.11 cfs
■ 10-year stormwater runoff peak flow after construction: 0.20 cfs
Stormwater flow calculations are provided in Appendix F.
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Stormwafer Pollution Prevention Plan
3.0 Construction Stormwater BMPs
3.1 The 12 BMP Elements
3.1.1 Element#1 —Mark Clearing Limits
To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of
construction will be clearly marked before land-disturbing activities begin. Trees that are to be
preserved, as well as all sensitive areas and their buffers, sha11 be clearly delineated,both in the
field and on the plans. In general, natural vegetation and native topsoil shall be retained in an
undisturbed state to the maximum extent possible. The BMPs relevant to marking the clearing
limits that will be applied for this project include:
• High Visibility Plastic or Metal Fence(BMP C103)
Clearing limits shall be established prior to the commencement of site preparation. The TESC
plan notes the location of silt fencing. These shall be installed before construction can begin and
shall be inspected and signed offby City of Renton inspectors.
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
3.1.2 Element#2 —Establish Construction Access
Construction access or activities occurring on unpaved areas shall be minimized, yet where
necessary, access points shall be stabilized to minimize the tracking of sediment onto public
roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent
sediment from entering state waters. All wash wastewater shall be controlled on site. The
specific BMPs related to establishing construction access that will be used on this project
include:
• Stabilized Construction Entrance (BMP C105)
The TESC plans note the location of the stabilized construction entrance. The entrance shall be
installed prior to site clearing. As site development progresses, the entrance will be inspected
and improved as needed to prevent erosion and transfer of materials off-site via truck tires.
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
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Stormwafer Pollution Prevention Plan
3.1.3 Element#3—Control Flow Rates
' In order to protect the properties and waterways downstream of the project site, stormwater
discharges from the site will be controlled. The specific BMPs for flow control that shall be used
on this project include:
• Sediment Trap (BMP C240)
In general, discharge rates of stormwater from the site will be controlled where increases in
impervious area or soil compaction during construction could lead to downstream erosion, or
where necessary to meet local agency stormwater discharge requirements (e.g. discharge to the
public storm drainage system).
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
3.1.4 Element#4 —Install Sediment Controls
All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal
BMP before leaving the construction site or prior to being discharged to an infiltration facility.
The specific BMPs to be used for controlling sediment on this project include:
• Straw Bale Barrier (BMP C230)
• Silt Fence(BMP C233)
• Sediment Trap (BMP C240)
� Storm Drain Inlet Protection(BVIP C220)
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Stormwater Pollution Prevention Plan �
If the BMP options listed above are deemed ineffective during construction, the Certified '
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
A silt fence shall be installed to prevent silt run-off from entering the existing public system.
Native vegetation will be maintained as much as possible outside the development areas to
provide additional buffers. As new storm drains and catch basins are installed on-site, filter
fabric will be utilized under all grates to catch sediment run-off. The temporary sediment trap
will be used to manage run-off from the interceptor dike and swales. Outfall from the trap will
be transferred to the existing storm sewer system.
In addition to the construction entry, sediment will be removed from vehicles tires via the use of
a wheel wash.
Sediment will also be removed from paved areas in and adjacent to construction work areas
manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle
tires away from the site and to minimize wash off of sediments from adjacent streets in runoff.
3.1.5 Element#5—Stabilize Soils
Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent
erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be
used on this project include:
• Temporary and Permanent Seeding(BMP C120)
• Mulching(BMP C 121)
� Nets and Blankets (BMP C122)
• Plastic Covering(BMP C123)
• Dust Control (BMP C 140)
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Stormwater Pollufion Prevention Plan
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain
exposed and unworked for mare than 7 days during the dry season(May 1 to September 30) and i�
2 days during the wet season(October 1 to Apri130). Regardless of the time of year, all soils I
shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather I
forecasts. '
In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be '�
temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, ,
protected with sediment trapping measures, and where possible,be located away from storm
drain inlets, waterways, and drainage channels.
Exposed and unworked soils will be seeded, mulched or covered with plastic as required.
3.1.6 Element#6—Protect Slopes
All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes
erosion. The following specific BMPs will be used to protect slopes for this project:
• Temporary and Permanent Seeding (BMP C120)
Slopes will be protected from erosion via seeding andlor plastic covering, as appropriate. Final
grades will be appropriately landscaped.
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
3.1.7 Element#7—Protect Drain Inlets
All storm drain inlets and culverts made operable during construction shall be protected to
prevent unfiltered or untreated water from entering the drainage conveyance system. However, �
the first priority is to keep all access roads clean of sediment and keep street wash water separate
from entering storm drains until treatment can be provided. Storm Drain Inlet Protection(BMP
C220)will be implemented for all drainage inlets and culverts that could potentially be impacted
by sediment-laden runoff on and near the project site. The following inlet protection measures
will be applied on this project:
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Stormwater PoNution Prevention Plan
Storm drain inlets shall be protected by catch basin inserts per BMP C220 in order to reduce
sediment loading and to prevent clogging of the storm drain system. The inlets shall be
inspected weekly at a minimum and daily during storm events. Inlet protection devices shall be
cleaned or removed and replaced before six inches of sediment can accumulate.
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
; manage this BMP element.
' 3.1.8 Element#8—Stabilize Channels and Outlets
;
Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural
drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for
channel and outlet stabilization that shall be used on this project include:
' • Channel Lining(BMP C202)
• Outlet Protection(BMP C209)
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
3.1.9 Element#9—Control Pollutants
All pollutants, including waste materials and demolition debris, that occur on site during
- construction shall be handled and disposed of in a manner that does not cause contamination of
�
stormwater. Woody debris may be chopped and spread on site.
' Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid
products, petroleum products, and non-inert wastes present on the site (see Chapter 173-304
WAC for the definition of inert waste).
Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic
system drain down, solvent and de-greasing cleaning operations, fuel tank drain down and
removal, and other activities which may result in discharge or spillage of pollutants to the ground
or into stormwater runoff must be conducted using spill prevention measures, such as drip pans.
Contaminated surfaces shall be cleaned immediately following any discharge or spill incident.
Emergency repairs may be performed on-site using temporary plastic placed beneath and, if
raining, over the vehicle.
Wheel wash or tire bath wastewater shall be discharged to a separate on-site treatment system or
to the sanitary sewer.
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Stormwater Pollution Prevention Plan
Application of agricultural chemicals including fertilizers and pesticides shall be conducted in a
manner and at application rates that will not result in loss of chemical to stormwater runoff.
Manufacturers' recommendations for application rates and procedures shall be followed.
BMPs shall be used to prevent or treat contamination of stormwater runoff by pH modifying
sources. These sources include bulk cement, cement kiln dust, fly ash, new concrete washing
and curing waters, waste streams generated from concrete grinding and sawing, exposed
aggregate processes, and concrete pumping and mixer washout waters. Stormwater discharges
shall not cause a violation of the water quality standard for pH in the receiving water.
BMPs C151 and C152 shall be used to reduce pollution from concrete and sawcutting.
The following good housekeeping practices will be followed on-site during the construction
project.
1. Only enough products required to do the job will be stored on-site.
2. All materials stored on-site will be stored in a neat, orderly manner in their
appropriate containers.
3. Products will be kept in their original containers with the original manufacturer's
labeL
4. Substances will not be mixed with one another unless recommended by the
manufacturer. '
5. Whenever possible, all of the product will be used up before disposing of the
container.
6. Manufacturers' recommendations for proper use and disposal will be followed.
7. The site superintendent will inspect the use and disposal of materials on-site on a
daily basis to ensure proper materials management.
8. There will be regular garbage, rubbish, construction waste, and sanitary waste
disposal. Self-contained temporary toilets will be furnished and used by all workers.
9. There will be prompt cleanup of any spills of liquid or dry materials that occur. �
10. Sediments that have been tracked by vehicles or have been transported by wind or
stormwater about the site or onto nearby roadways will be cleaned up.
11. No emulsifiers, dispersants, soaps, detergents or surfactants shall be allowed to enter
the stormwater system.
- If the BMP options listed above are deemed ineffective during construction, the Certified I
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively �
manage this BMP element.
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Stormwater Pollution Prevention Plan
3.1.10 Element#10—Control Dewatering
All dewatering water from open cut excavation, tunneling, foundation work, trench, or
underground vaults shall be discharged into a controlled conveyance system prior to discharge to
a sediment trap. Channels will be stabilized, per Element#8. Clean, non-turbid dewatering
water will not be routed through stormwater sediment traps, and will be discharged to systems
tributary to the receiving waters of the State in a manner that does not cause erosion, flooding, or
a violation of State water quality standards in the receiving water. Highly turbid dewatering
water from soils known or suspected to be contaminated, or from use of construction equipment,
will require additional monitoring and treatment as required for the specific pollutants based on
the receiving waters into which the discharge is occurring. Such monitoring is the responsibility
of the contractor.
However, the dewatering of soils known to be free of contamination will trigger BMPs to trap
sediment and reduce turbidity. At a minimum, geotextile fabric socks/bags/cells will be used to
filter this material. Other BMPs to be used for sediment trapping and turbidity reduction include
the following:
■ Concrete Handling(BMP C151)
■ Use of a sedimentation bag, with outfall to a ditch or swale for small
volumes of localized dewatering.
If the BMP options listed above are deemed ineffective during construction, the Certified
Erosion and Sediment Control Lead shall implement other BMP's as necessary to effectively
manage this BMP element.
3.1.11 Element#11 —Maintain BMPs
All temporary and permanent erosion and sediment control BMPs shall be maintained and
repaired as needed to assure continued performance of their intended function. Maintenance and
repair shall be conducted in accordance with each particular BMP's specifications. Visual
monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours
of any rainfall event that causes a discharge from the site. If the site becomes inactive, and is
temporarily stabilized, the inspection frequency will be reduced to once every month.
All temporary erosion and sediment control BMPs shall be removed within 30 days after the
final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped
sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs
or vegetation shall be permanently stabilized.
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Stormwater Pollution Prevention Plan
3.1.12 Element#12 —Manage the Project
Erosion and sediment control BMPs for this project have been designed based on the following
principles:
' ■ Design the project to fit the existing topography, soils, and drainage
patterns.
■ Emphasize erosion control rather than sediment control.
■ Minimize the extent and duration of the area exposed.
■ Keep runoff velocities low.
■ Retain sediment on site.
■ Thoroughly monitor site and maintain all ESC measures.
■ Schedule major earth«�ork during the dry season.
In addition, project management will incorporate the key components listed below:
As this project site is located west of the Cascade Mountain Crest, the project will be managed
according to the following key project components:
I_ Phasing of Construction
■ The construction project is being phased to the extent practicable in order
to prevent soil erosion, and,to the maximum extent possible, the transport
of sediment from the site during construction.
i
' ■ Revegetation of exposed areas and maintenance of that vegetation shall be
an integral part of the clearing activities during each phase of construction,
per the Scheduling BMP (C 162).
Seasonal Work Limitations
■ From October 1 through April 30, clearing, grading, and other soil
,
disturbing activities shall only be permitted if shown to the satisfaction of
' the local permitting authority that silt-laden runoff will be prevented from
- leaving the site through a combination of the following:
❑ Site conditions including existing vegetative coverage, slope, soil
- type, and proximity to receiving waters; and
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Stormwater Pollution Prevention Plan
❑ Limitations on activities and the extent of disturbed areas; and
❑ Proposed erosion and sediment control measures.
■ Based on the information provided and/or local weather conditions, the
local pernutting authority may expand or restrict the seasonal limitation on
site disturbance.
■ The following activities are exempt from the seasonal clearing and grading
limitations:
o Routine maintenance and necessary repair of erosion and sediment
control BMPs;
o Routine maintenance of public facilities or existing utility
structures that do not expose the soil or result in the removal of the
vegetative cover to soil; and
❑ Activities where there is 100 percent infiltration of surface water i
runoff within the site in approved and installed erosion and
sediment control facilities.
Coordination`��ith Utilities and Other Jurisdictions
■ Care has been taken to coordinate with utilities, other construction
projects, and the local jurisdiction in preparing this SWPPP and
scheduling the construction work.
Inspection and Monitoring
■ All BMPs shall be inspected, maintained, and repaired as needed to assure
continued performance of their intended function. Site inspections shall
� be conducted by a person who is knowledgeable in the principles and
; practices of erosion and sediment control. This person has the necessary
skills to:
❑ Assess the site conditions and construction activities that could
impact the quality of stormwater, and
❑ Assess the effectiveness of erosion and sediment control measures
used to control the quality of stormwater discharges.
■ A Certified Erosion and Sediment Control Lead shall be on-site or on-call
at all times.
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Stormwater Pollution Prevention Plan
■ Whenever inspection and/or monitoring reveals that the BMPs identified
in this SWPPP are inadequate, due to the actual discharge of or potential �
to discharge a significant amount of any pollutant, appropriate BMPs or
design changes shall be implemented as soon as possible. II,
'�_ I
Maintaining an Updated Construction SWPPP I,
;- ,
■ This SWPPP shall be retained on-site or within reasonable access to the '
site.
' ■ The SWPPP shall be modified whenever there is a change in the design,
construction, operation, or maintenance at the construction site that has, or
could have, a significant effect on the discharge of pollutants to waters of �
the state.
■ The SWPPP shall be modified if, during inspections or investigations
conducted by the owner/operator, or the applicable local or state
regulatory authority, it is determined that the SWPPP is ineffective in
eliminating or significantly minimizing pollutants in stormwater
discharges from the site. The SWPPP shall be modified as necessary to
include additional or modified BMPs designed to correct problems
identified. Revisions to the SWPPP shall be completed within seven(7)
days following the inspection.
3.2 Site Specific BMPs
Site specific BMPs are shown on the TESC Plan Sheet included in Appendix A.
3.3 Additional Advanced BMPs
I�To additional advanced BMP's are proposed for the project.
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IStormwater Pollufron Prevention P/an
I 4.0 Construction Phasing and BMP
Implementation
�
The BMP implementation schedule will be driven by the construction schedule. As of
� the date of the preparation of this document,permit issuance was pending and
consequently, the start of construction is not known. When the actual construction
schedule is known, a BMP implementation schedule will be prepared and included with
� this document.
1 5.0 Pollution Prevention Team
' S.1 Roles and Responsibilities
� The pollution prevention team consists of personnel responsible for implementation of the
SWPPP, including the following:
� ■ Certified Erosion and Sediment Control Lead (CESCL)—primary
contractor contact, responsible for site inspections (BMPs, visual
monitoring, sampling, etc.); to be called upon in case of failure of any �I,
IESC measures. �
■ Resident Engineer—For projects with engineered structures only
' (sediment ponds/traps, sand filters, etc.): site representative for the owner
that is the project's supervising engineer responsible for inspections and �
1 issuing instructions and drawings to the contractor's site supervisor or
representative
� ■ Emergency Ecology Contact—individual to be contacted at Ecology in
case of emergency. Puget Sound Regional Office: 425-649-7000.
I ■ Emergency Owner Contact=individual that is the site owner or
representative of the site owner to be contacted in the case of an
emergency.
� ■ Non-Emergency Ecology Contact—individual that is the site owner or
representative of the site owner than can be contacted if required.
' ■ Monitoring Personnel—personnel responsible for conducting water '�
quality monitoring; far most sites this person is also the Certified Erosion I
' and Sediment Control Lead.
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Stormwater Pollufion Prevention Plan
6.1.2 Site Inspection Documentation
The site inspector will record each site inspection using the site log inspection forms provided in
Appendix E. The site inspection log forms may be separated from this SWPPP document,but
will be maintained on-site or within reasonable access to the site and be made available upon
request to Ecology or the local jurisdiction.
6.2 Stormwater Quality Monitoring
6.2.1 Turbidity Sampling
Monitoring requirements for the proposed project will include either turbidity or water
transparency sampling to monitor site discharges for water quality compliance with the 2005
Construction Stormwater General Permit(Appendix D). Sampling will be conducted at all
' discharge points at least once per calendar week.
' � Turbidity or transparency monitoring will follow the analytical methodologies described in
Section S4 of the 2005 Construction Stormwater General Permit(Appendix D). The key
benchmark values that require action are 25 NTU for turbidity(equivalent to 32 cm
transparency) and 250 NTU for turbidity (equivalent to 6 cm transparency). If the 25 NTLT
benchmark for turbidity(equivalent to 32 cm transparency) is exceeded, the following steps will
be conducted:
1. Ensure all BMPs specified in this SWPPP are installed and functioning as
intended.
2. Assess whether additional BMPs should be implemented, and document
revisions to the SWPPP as necessary.
3. Sample discharge location daily until the analysis results are less than 25
NTU (turbidity) or greater than 32 cm(transparency).
If the turbidity is greater than 25 NTU (or transparency is less than 32 cm)but less than 250 '
NTU (transparency greater than 6 cm) for more than 3 days, additional treatment BMPs will be
implemented within 24 hours of the third consecutive sample that exceeded the benchmark ',
value. Additional treatment BMPs to be considered will include,but are not limited to, off=site I�
treatment, infiltration, filtration and chemical treatment. �'
If the 250 NTU benchmark for turbidity(or less than 6 cm transparency) is exceeded at any time,
the following steps will be conducted:
1. Notify Ecology by phone within 24 hours of analysis (see Section 5.0 of
this SWPPP for contact information).
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Stormwater Pollution Prevention Plan
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� Stormwater Pollution Prevention Plan
, 7.0 Reporting and Recordkeeping
� 7.1 Recordkeeping �
7.1.1 Site Log Book I
� A site log book will be maintained for all on-site construction activities and will include: �
I ■ A record of the implementation of the SWPPP and other permit
requirements;
� ■ Site inspections; and,
■ Stormwater quality monitoring.
� For convenience, the inspection form and water quality monitoring forms included in this
� SWPPP include the required information for the site log book.
7.1.2 Records Retention
t Records of all monitoring information (site log book, inspection reports/checklists, etc.), this
Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit
I requirements will be retained during the life of the construction project and for a minimum of
three years following the termination of permit coverage in accordance with permit condition
SS.C.
�
7.1.3 Access to Plans and Records
jThe SWPPP, General Permit,Notice of Authorization letter, and Site Log Book will be retained
on site or within reasonable access to the site and will be made immediately available upon
� request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology
within 14 days of receipt of a written request for the SWPPP from Ecology. Any other
information requested by Ecology will be submitted within a reasonable time. A copy of the
� SWPPP or access to the SWPPP will be provided to the public when requested in writing in
accordance with permit condition SS.G.
1 7.1.4 Updating the SWPPP
( In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be
modified if the SWPPP is ineffective in eliminating or significantly minimizing pollutants in
stormwater discharges from the site or there has been a change in design, construction, operation,
� or maintenance at the site that has a significant effect on the discharge, or potential for discharge,
( 25
Draina2e Report for Younker Nissan April S. 2007
�
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Stormwater Pollution Prevention Plan
Appendix B — Construction BMPs
I
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;I
Zs
BMP C103: High Visibility Plastic or Metal Fence �
Purpose Fencing is intended to: (1)restrict clearing to approved limits; (2)prevent
disturbance of sensitive areas,their buffers, and other areas required to be
left undisturbed; (3)limit construction traffic to designated construction
entrances or roads; and, (4)protecf areas where marking with survey tape
may not provide adequate protection. I
Conditions of Use To establish clearing limits,plastic or metal fence may be used: II
• At the boundary of sensitive areas,their buffers, and other areas '
required to be left uncleared.
• As necessary to control vehicle access to and on the site. '
Design and • High visibility plastic fence shall be composed of a high-density
Installation polyethylene material and shall be at least four feet in height. Posts
Specifications for the fencing shall be steel or wood and placed every 6 feet on
center(maarimum) or as needed to ensure rigidity. The fencing shall
be fastened to the post every s�inches with a polyethylene tie. On
long continuous lengths of fencing, a tension wire or rope shall be
used as a top stringer to prevent sagging between posts. The fence
color shall be high visibility orange. The fence tensile strength shall
be 3601bs./ft. using the ASTM D4595 testing method.
• Metal fences shall be designed and installed according to the
manufacturer's speci_fications.
• Metal fences shall be at least 3 feet high and must be highly visible.
• Fences shall not be wired or stapled to trees.
Maintenance • If the fence has been damaged or visibility reduced,it shall be
Standards repaired or replaced itnmediately and visibility restored.
4-6 Vo/ume!1— Construction Stormwater Pollution Prevention February 2005
BMP C105: Stabilized Construction Entrance
Purpose Construction entrances are stabilized to reduce the amount of sediment
transported onto paved roads by vehicles or equipment by constructing a
stabilized.pad of quarry spalls at entrances to construction sites.
Conditions of Use Construction eritrances shall be stabilized wherever traffic will be leaving
a construction site and txaveling on paved roads or other paved areas
within 1,000 feet of the site.
On large commercial,highway,and road projects,the designer should
include enough extra materials in the contract to allow for additional
stabilized entrances not shown in the initial Construction SWPPP. It is
difficult to deterniine exactly where access to these projects will take
place; additional materials will enable the contractor to install them where
needed. �
Design and • See Figure 4.2 for details. Note:the 100' minimum length of the
Installation entrance shall be reduced to the maximum practicable size when the
� Specifications size or configuration of the site does not allow the full length(100').
• A separation geotextile shall be placed under the spalls to prevent
fine sedi.ment from pumping up into the rock pad. The geote�ile
shall meet the following standards:
Grab Tensile Strength (ASTM D4751) 200 psi min.
Grab Tensile Elongation(ASTM D4632) 30% max. 5
Mullen Burst Strength (ASTM D3786-80a) 400 psi min.
AOS (ASTM D4751) 20-45(U.S. standard sieve size)
• Consider early installation of the first lift of asphalt in areas that will
paved; this can be used as a stabilized entrance. Also consider the
installation of excess concrete as a stabilized entrance. During large
concrete pours,excess concrete is often available for this purpose.
• Hog fuel(wood-based mulch)may be substituted for or combined with
quarry spalls in areas that will not be used for permanent roads.Hog
fuel is generally less effective at stabilizing construction entrances and
should be used only at sites where the amount of traffic is very li.mited.
Hog fuel is not recommended for entrance stabilization in urban areas.
The effectiveness of hog fuel is highly variable and it generally
requires more maintenance than quarry spalls. The inspector may at
any ti.me require the use of quarry spalls if the hog fuel is not
preventing sediment from being tracked onto pavement or if the hog
fuel is being carried onto pavemen� Hog fuel is prohibited in
permanent roadbeds because organics in the subgrade soils cause
degradation of the subgrade support over ti.me.
• Fencing(see BMPs C103 and C104) shall be installed as necessary to
restrict traffic to the construction entrance.
4-8 Volume fl— Construcfion Stormwater Pollution Prevention February 2005
• Whenever possible,the entrance shall be constructed on a firm,
{ compacted subgrade. This can substantially increase the effectiveness
of the pad and reduce the need for maintenance.
Maintenance • Quarry spalls(or hog fuel) shall be added if the pad is no longer in
Standards accordance with the specifications.
•� If the entrance is not preventing sediment from being tracked onto
pavement,then alternative measures to keep the streets free of
sediment shall be used. This may i.nclude street sweeping, an increase �
' in the dimensions of the entrance, or the installation of a wheel wash. ',
• Any sediment that is tracked onto pavement shall be removed by �I
shoveling or street sweeping. The sediment collected by sweeping
shall be removed or stabilized on site. The pavement shall not be ,
cleaned by washi.ng down the street,except when sweeping is '
ineffective and there is a threat to public safety. If it is necessary to
wash the streets,the construction of a small sump shall be considered.
The sediment would then be washed into the sump where it cari be
controlled.
• Any quarry spalls that are loosened from the pad,which end up on the
roadway shall be removed immediately.
• If vehicles are entering or exiting the site at points other than the
construction entrance(s),fencing(see BMPs C103 and C104) shall be ,
— installed to control traffic. '
• Upon project completion and site stabilization, all construction ,
accesses intended as permanent access for maintenance shall be ,
permanently stabilized. '
Driveway shaA meet the � ���
requiiements of the I
Pa��^9 a9�Y ''
It is recommended that
the eMrar�ce be
' � crowned so that runoff
�oBa � drains oH the pad �
Ex`�� i
��
3y
i
d
Insta➢dr(veway culvert
�there is a roadside
d'dch preseM
4�-8�quarp'sPalls
Geotextila
�5�c �`�.
1 Z"min.thlckness_� /�� .
Provide fuA widih of
inpresslepress area
i
Figure 4.2–Stabilized Construction Entrance I;,
February 2005 Volume !1–Construction Stormwater Pollution Prevention 4-9
BMP C106: Wheel Wash �
Purpose Wheel washes reduce the amount of sediment transported onto paved
roads by motor vehicles.
Conditions of Use When a stabilized construction entrance(see BMP C105) is not preventing
- sedi.ment from being tracked onto pavement.
.
Wheel waslvng is generally an effective BMP when installed with
careful attention to topography. For example, a wheel wash can be
detrimental if installed at the top of a slope abutting a right-of-way
where the water from the dripping truck can run ununpeded into the
�� street.
• Pressure washing combined with an adequately sized and surfaced pad
with direct drainage to a large 10-foot x 10-foot sump can be very
effective.
Design and Suggested details are shown in Figure 4.3. The Local Permitting
Installation Authority may allow other designs. A minimum of 6 inches of asphalt
Specifications treated base(ATB)over crushed base material or 8 inches over a good
subgrade is recommended to pave the wheel wash.
� Use a low clearance truck to test the wheel wash before paving. Either a
belly dump or lowboy will work well to test clearance.
Keep the water level from 12 to 14 inches deep to avoid damage to truck ,,^
hubs and filling the truck tongues with water.
Midpoint spray nozzles are only needed in extremely muddy conditions.
Wheel wash systems should be designed with a small grade change,6 to
12 inches for a 10-foot-wide pond,to allow sediment to flow to the low
side of pond to help prevent re-suspension of sediment. A drainpipe with
a 2-to 3-foot riser should be installed on the low side of the pond to allow
for easy cleaning and refilling. Polymers ma.y be used to promote
coagulation and flocculation in a closed-loop system. Polyacrylamide
(PA1V�added to the wheel wash water at a rate of 0.25 - 0.5 pounds per
1,000 gallons of water increases effectiveness and reduces cleanup ti.me.
If PA1VI is already bein.g used for dust or erosion control and is being
applied by a water huck,the same truck can be used to change the wash
water.
Maintenance The wheel wash should start out the day with fresh water.
Standards 'I'he wash water should be changed a minimum of once per day. On
large earthwork jobs where more than 10-20 trucks per hour are
expected,the wash water will need to be changed more often,
Wheel wash or tire bath wastewater shall be discharged to a separate on-
site treatment system, such as closed-loop recirculation or land
application, or to the sanitary sewer with proper local sewer distr�ct
approval.
4-10 Volume!!-Construction Stormwa�er Pollution Prevention February 2005
( -
"Schedule 40
1 '/i'schedule 4Q for sprayers
Y
�.r
�^ � �
2% 5:1 5:1 I f 2%
Slope Slope ' Slope Slope
1l
� � ,
, 1�1_ . _._
Slo�pe
Wheel Wash Plan
�15�15 20' 15� 5Q' �
Elevation Vew
,Vlfater level
�� � 1:1 Slope
_�
L____--1�---� '
Section A-A I
' • N.T.S.
I
Figure 4.3 Wheel Wash
Notes:
1. Asphalt construction entrance 6 in. asphalt treated base(ATB). �
2. 3-inch trash pump with floats on the suction hose. '
3. Midpoint spray nozzles, if needed.
4. 6-inch sewer pipe with buttertly valves. Bottom one is a drain. Locate top pipe's invert 1 foot
above bottom of wheel wash.
5. 8 foot x 8 foot sump with 5 feet of catch. Build so can be deaned with trackhoe. ,
6. Asphalt curb on the Iow road side to direct water back to pond.
7. 6-inch sleeve under road.
8. Ball valves.
9. 15 foot. ATB apron to protect ground from splashing water.
February 2005 Volume U— Construction Stormwater Pollu�ion Prevention 4-11
� BMP C120: Temporary and Permanent Seeding
Purpose Seeding is intended to reduce erosion by stabilizing exposed soils. A
well-established vegetative cover is one of the most effective methods of
reducing erosion.
Conditions of Use • Seeding may be used throughout the project on disturbed areas that
have reached final grade or that will remain unworked for more than
30 days.
�!, • Channels that will be vegetated should be installed before major
earthwork and hydroseeded with a Bonded Fiber Matr�. The
vegetation should be well established(i.e., 75 percent cover)before
water is allowed to flow in the ditch. With channels that will have -
, � high flows,erosion control blankets should be installed over the
hydroseed. If vegetation cannot be established from seed before water
is allowed in the ditch, sod should be installed in the bottom of the
� ditch over hydromulch and blankets.
I • Retention/detention ponds should be seeded as required.
' • Mulch is required at all times because it protects seeds from heat,
� - moisture loss, and transport due to runoff.
• All disturbed areas shall be reviewed in late August to early September
_-- and all seeding should be completed by the end of September.
�.. Otherwise,vegetation will not establish itself enough to provide more
than average protection.
. • At final site stabilization,all disturbed areas not otherwise vegetated or
stabilized shall be seeded and mulched. Final stabilization means the
completion of all soil disturbing activities at the site and the
establishment of a permanent vegetative cover, or equivalent '
permanent stabilization measures (such as pavement,riprap, gabions I
. or geote�iles)which will prevent erosion. _ I
Design and • Seeding should be done during those seasons most conducive to i
Installation ���d will vary with the cli.mate conditions of the region. ,,
Specifua�ions Local experience should be used to determine the appropriate '
seeding periods.
• The optimum seeding windows for western Washington are April 1
through June 30 and September 1 through October 1. Seeding that
occurs between July 1 and August 30 will require irrigation unti175
percent grass cover is established, 5eeding that occurs between
October 1 and March 30 will require a mulch or plastic cover until
75 percent grass cover is established.
• To prevent seed from being washed away,confirm that all required
surface water control measures have been installed
i '
February 2005 Volume ll-Construction Stormwater Po�lution Prevention 4-13
- • The seedbed should be firm and rough. All soil should be roughened ,
no matter what the slope. If compaction is required for engineering
purposes, slopes must be track walked before seeding. Backbladi.ng or
smoothing of slopes greater than 4:1 is not allowed if they are to be
seeded.
• New and more effective restoration-based landscape practices rely on
deeper incorporation than tliat provided by a si.mple single-pass
rototilling treatment. Wherever practical the subgrade should be .
� initially ripped to improve long-term permeability, infiltration,and
water inflow qualities. At a minimum,permanent areas shall use soil
amendments to achieve organic matter and permeability performance
defined in engineered soiUlandscape systems. For systems that are
deeper than 8 inches the rototilling process should be done in multiple
lifts,or the prepared soil system shall be prepared properly and then
placed to achieve the specified depth.
• Organic matter is the most appropriate form of"fertilizer"because it
provides nutrients(including nitrogen,phosphorus,and potassium) in
the least water-soluble form. A natural system typically releases 2-10
percent of its nutrients annually. Chemical fertilizers have since been
formulated to simulate what organic matter does naturally.
• In general, 10-4-6 N-P-K(nitrogen-phosphorus-potassium� fertilizer
can be used at a rate of 90 pounds per acre. Slow-release fertilizers ;
should always be used because they are more efficient and have fewer
environmental impacts. It is recommended that areas being seeded for
final landscaping conduct soil tests to determ.i.ne the exact type and
quantity of fertilizer needed. This will prevent the over-application of
fertilizer. Fertilizer should not be added to the hydromulch machine
and agitated more than 20 minutes before it is to be used if agitated
too much,the slow-release coating is destroyed.
• There are numerous products available on the market that take the
place of chemical fertilizers. These include several with seaweed �
extracts that are beneficial to soil microbes and organisms. If 100
percent cottonseed meal is used as the mulch in hydroseed, chemical
fertilizer may not be necessary. Cottonseed meal is a good source of
long-term, slow-release, available nitrogen.
• Hydroseed applications shall include a m;n;mum of 1,500 pounds per ,
acre of mulch with 3 percent tackifier. Mulch may be made up of 100 ��I
percent: cottonseed meal; fibers made of wood, recycled cellulose, I
hemp, and kenaf; compost; or blends of these. Tackifier shall be plant-
based, such as guar or alpha plantago, or chemical-based such as
polyacrylamide or polymers. Any mulch or tackifier product used
shall be installed per manufacturer's instructions. Generally,mulches
come in 40-50 pound bags. Seed and fertilizer are added at time of
application.
414 Volume ll—Cons6-uction Stormwater Pollufion Prevenfion Fe6ruary 2005
� • Mulch is always required for seeding. Mulch can be applied on top of '�
the seed or simultaneously by hydroseeding.
• On steep slopes,Bonded Fiber Matrix(BF1V�or Mechanically Bonded
Fiber Matrix (MBFIV�products should be used. BFM/MBFM
products are applied at a m;nimum rate of 3,000 pounds per acre of
mulch with approxi_mately 10 percent tackifier. Application is made
so that a�_mum of 95 percent soil coverage is achieved. Numerous
products are available commercially and should be installed per
� manufacturer's instructions. Most products require 24-36 hours to
cure before a rainfall and cannot be installed on wet or saturated soils.
Generally,these products come in 40-50 pound bags and include all
necessary ingredients except for seed and fertilizer.
r
! BFMs and MBFMs have some advantages over blankets:
• No surface preparation required;
• Can be installed via helicopter in remote areas;
• On slopes steeper than 2.5:1, blanket installers may need to be roped
and harnessed for safety;
• They are at least$1,000 per acre cheaper installed.
— In most cases,the shear strength of blankets is not a factor when used on
� slopes, only when used in channels. BFMs and MBFMs are good
alternatives to blankets in most situations where vegetation establishment
is the goal.
• When installing seed via hydroseeding operations, only about 1/3 of
the seed actually ends up in contact with the soil surface. This reduces
the ability to establish a good stand of grass quickly. One way to
overcome this is to increase seed quantities by up to 50 percent. ,
• Vegetation establishment can also be enhanced by dividing the 'i
hydromulch operation into two phases: I,
1. Phase 1-Install all seed and fertilizer with 25-30 percent mulch I
and tackifier onto soil in the first lift;
2. Phase 2-Install the rest of the mulch and tackifier over the first lift.
An alternative is to install the mulch, seed, fertilizer, and tackifier in one
lift. Then, spread or blow straw over the top of the hydromulch at a rate of
about 800-1000 pounds per acre. Hold straw in place with a standard
tackifier. Both of these approaches will increase cost moderately but will
greatly improve and enhance vegetative establishmen� The increased cost
may be offset by the reduced need for:
1. Irrigation
2. Reapplication of mulch '
3. Repair of failed slope surfaces
February 2005 Volume ll–Construction Stormwater Pollufion Prevention 415
This technique works with standard hydromulch(1,500 pounds per acre
minimum)and BFMIMBFMs (3,000 pounds per acre minimum).
• Areas to be permanently landscaped shall provide a healthy topsoil
that reduces the need for fertilizers,i.mproves overall topsoil quality,
provides for better vegetal health and vitaliiy, improves hydrologic
characteristics,and reduces the need for irrigation. This can be
acconiplished in a number of ways:
Recent research has shown that the best method to ixnprove till soils is
to amend these soils with compost. The optimum mixture is
approximately two parts soil to one part compost. This equates to 4
inches of compost mixed to a depth of 12 inches in till soils. Increasing
the concentration of compost beyond this level can have negative
effects on vegetal health,while decreasing the concentrations can
reduce the benefits of amended soils. Please note: The compost should
meet specifications for Grade A quality compost in Ecology
Publication 94-038.
Other soils, such as gravel or cobble outwash soils, may require
different approaches. Organics and fines easily migrate through the
loose structure of these soils. Therefore,the i.mportation of at least 6
inches of quality topsoil,underlain by some type of filter fabric to
prevent the migration of fines,may be more appropriate for these soils. '
Areas that akeady have good topsoil, such as u.ndisturbed areas, do not
require soil amendments.
• Areas that will be seeded only and not landscaped may need compost
or meal-based mulch i.ncluded in the hydroseed in order to establish
vegetation. Native topsoil should be re-installed on the disturbed soil
surface before application.
• Seed that is installed as a temporary measure may be insta.11ed by hand
if it will be covered by straw,mulch, or topsoil. Seed that is installed
as a permanent measure may be installed by hand on sma.11 areas
(usually less than 1 acre)that will be covered with mulch,topsoil, or
erosion blankets. The seed mixes listed below include recommended
mixes for both temporary and permanent seeding. These mixes,with
the exception of the wetland mix, shall be applied at a rate of 120
pounds per acre. This rate can be reduced if soil amendments or slow
release fertilizers aze used. Local suppliers or the local conservation
district should be consulted for their recommendations because the
appropriate mix depends on a variety of factors, including location,
exposure, soil type, slope, and expected foot traffic. Alternative seed
mixes approved by the local authority may be used.
. 4-16 Volume ll—Consbruction Stormwafer Pollution Prevention February 2005
- Table 4.1 represents the standard mix for those areas where just a
' temporary vegetative cover is required.
Table 4.1
Tem ora Erosion Control Seed Mix
%We' ht %Puri %Germination
Chewings or annual blue grass 40 98 90
Festuca rubra var. commutata or Poa cmna
Perennial rye- 50 98 90
Lolium erenne
Redtop or colonial bentgrass 5 92 85
A ostis alba orA ostis tenuis
� White dutch clover 5 98 90
Tri olium re ens
Table 4.2 provides just one recommended possibility for landscaping seed
Table 4.2
Landsca in Seed Mix �
%Wei ht %Puri %Germination
� Perennial.rye blend 70 98 90
� Lolium erenne
Chewings and red fescue blend 30 98 90
Festuca rubra var. commutata
or Festuca rubra
This turf seed mix in Talile 4.3 is for dry situations where there is no need
for much water. The advantage is that this m�requires very little
� maintenance.
Tabie 4.3
Low-Growin Turf Seed Mix
% R'ei ht %Puri %Germination
Dwarf tall fescue(several varieties) 45 98 90
Festuca arundinacea var.
Dwarf perennial rye(Barclay) 30 98 90
Lolitan erenne var:barcl
Red fescue 20 98 90
Festuca rubra
Colonial bentgrass 5 98 90
A ostis tenuis
Table 4.4 presents a mix recommended for bioswales and other
intermittently wet areas.
Tabie 4.4
Bioswale Seed Mix*
%R'ei ht %Pnri %Germinatioa
Tall or meadow fescue 75-80 98� 90
Festuca mYmdinacea or Festuca elatior
Seaside/Creeping bentgrass 10-15 92 85
A ostis alustris
Redtop bentgrass 5-10 90 80
A ostis albaorA ostis ' cmtea
*Mod�ed Briargreen,Ina Hydroseeding Guide Wetlands Seed Mix
February 2005 Volume 11— Construction Stormwafer Pollution Prevenfion 4-17
The seed mix shown in Table 4.5 is a recommended low-growing, , I,
;
relatively non-invasive seed mix appropriate for very wet areas that aze i,
not regulated wetlands. Other m�es may be appropriate, depending on !
the soil type and hydrology of the area. Recent research suggests that 'I
bentgrass(agrostis sp.) should be emphasized i.n.wet-area seed mixes. '
Apply this mixture at a rate of 60 pounds per acre.
Table 4.5
Wet Area Seed Mix*
%R'ei ht %Puri %Germination
Tall or meadow fescue 60-70 98 90
Festuca arundinacea or
Festuca elatior
Seaside/Creeping bentgrass 10-15 . 98 85
A ostis alustris
Meadow foxtail 10-15 90 80
Ale ocurus ratensis
Alsike clover 1-6 98 90
Tri olium bridum
Redtop bentgrass 1-6 92 85
A ostis alba
� *Modified Briargreen,Inc. Hydroseeding Guide Wetlands Seed Mix
The meadow seed m�in Table 4.6 is recommended for areas that will be
maintained infrequently or not at all and where colonization by native
. plants is desirable. Likely applications include rural road and utility right- �
of-way. Seeding should take place in September or very early October in �
order to obtain adequate establishment prior to the winter months. The
appropriateness of clover in the mix may need to be considered, as this can
be a fairly invasive species. If the soil is amended,the addition of clover
may not be necessary. _
Table 4.6
Meadow Seed Mix
%We' ht %Puri %Germination
Redtop or Oregon bentgrass 20 92 85
A artis alba or A astis are onensis
Red fescue � 70 98 90
Festuca rubra
White dutch clover 10 98 90
Tri olium r errs
Maintenance • Any seeded areas that fail to establish at least 80 percent cover(100
Standardr percent cover for areas that receive sheet or concentrated flows) shall
be reseeded. If reseeding is ineffective, an alternate method, such as
soddi.ng,mulching, or nets/blankets, shall be used. If wi.nter weather
prevents adequate grass growth,this time limit may be relaxed at the
discretion of the local authority when sensitive areas would otherwise
be protected. .
9-18 Vo/ume 11—Construcfion Stormwater Pollution Prevention February 2005
• After adequate cover is achieved, any areas that experience erosion
' shall be reseeded and protected by muleh. If the erosion problem is
drainage related,the problem shall be fixed and the eroded area
reseeded and protected by mulch.
• Seeded areas shall be supplied with adequate moisture,but not watered
to the e�rtent that it causes runoff.
r� I�I
' I
�
February 2005 Volume ll— Construction Sformwafer Pollution Prevention 4-99
I f
BMP C121: Mulching i
Purpose The purpose of mulching soils is to provide immediate temporary
protection from erosion. Mulch also enhances plant establishment by �
conserving moisiure,holding fertilizer, seed, and topsoil in place, and
moderating soil temperatures. There is an enormous variety of mulches
that can be used Only the most common types are discussed in this
section.
Conditions of Use As a temporary cover measure,mulch should be used:
• On disturbed areas that require cover measures for less than 30 days.
• As a cover for seed during the wet season and during the hot summer
months.
• Duzing the wet season on slopes steeper than 3H:1V with more than 10
feet of vertical relief.
� • Mulch may be applied at any time of the year and must be refreshed
periodically. .
Design and For mulch materials, application rates, and specifications, see Table 4.7.
Installation Note: Thicknesses may be increased for disturbed areas in or near
Specifications sensitive areas or other areas highly susceptible to erosion. '
Mu1ch used within the ordinary high-water mark of surface waters should �
be selected to minimi7e potential flotation of organic matter. Composted
organic materials have higher specific gravities(densities)than straw,
wood, or chipped material.
Maintenance • The thickness of the cover must be maintained.
Standards �y�eas that experience erosion shall be remulched andlor protected
• with a net or blanket. If the erosion problem is drainage related,then
the problem shall be f�ed and the eroded area remulched
i
4-20 Volume Il-Construction Sformwafer Pollution Prevention February 2005
Table 4.7 III
� Mulch Standards and Guidelines '
Mulch Application '
Material Quali Standards Rates Remarks ,
Straw Air-dried;free from 2"-3"thick;5 Cost-effective protection when applied with adequate
undesirable seed and bales per 1000 sf thickness. Hand-application generally requires greater
coarse material. or 2-3 tons per thickness than blowv straw.The thiclmess of straw may be
acre reduced by half when used in conjunction with seeding. In
windy areas straw must be held in piace by crimping,using a
taclafier,or cov�-+ng with netting. Blown straw always has
to be held in place with a tackifier as even light winds will
blow it away.Straw,however,has several deficiencies that
should be considered when selecting mulch materials.It
often inh�oduces and/or encourages the propagation of wced
species and it has no significant long-term benefits. Straw
should be used only if mulches with long-term benefits are
unavailable locally. It should aLso not be used within the
ordinary high-water elevation of surface waters(due to
flotadon). '
Hydromulch No growth Approx.25-30 Shall be applied with hydromulcher. Shall not be used
inhibiting factors, lbs per 1000 sf without seed and tackifier unless the application rate is at
or 1500 -2000 least doubled. Fibers longer than about 3/a-1 inch clog
lbs per acre hydromulch equipment. Fibers should be kept to less than'/a
inch.
Composted � No visible water or 2"thick min.; More effective control can be obtained by increasing
Mulch and dust during approx 100 tons thickness to 3". Excellent mulch for protecting final grades
Compost handling. Must be per acre(approx. until landscaping because it can be directly seeded or tilled
� purchased from 8001bs per yard) into soi�as an amendment. Composted mulc�has a coazser
supplier with Solid size gradation than compost.It is more stable and practical
_ Waste Handling to use in wet areas and during rainy weather conditions.
Permit(unless
exempt).
Chipped Site Average size shall 2"minimum This is a cost-effective way to dispose of debris from
Vegetation be several inches. thiclrness clearing and grubbing,and it eli.minates the problems
' Gradations from associated with bum.ing. Generally,it should not be used on
fines�0 6 inches in slopes above approx. 10%because of its tendency to be
' length for texture, transported by ruuo� It is not recommended within 200
va�iation,and feet of surface waters: If seeding is expected shortly after I
interlocking mulch,the decomposition of the chipped vegetation may tie
properties. up nutrients important to grass establishment �
Wood based No visible water or 2"thick;approx. This material is oft�called"hog or hogged fueL" It is
Mu1ch dust during 100 tons per acre usable as a mateaial for Stabilized Construction Fntrances
handling. Must be (approx,8001bs. (BMP C105)and as a mulch. The use of mulch uttimately
purchased&om a per cubic yard) improves the organic matter in the soil. Special caution is
'— ' supplier with a Solid advised regarding the source and composition of wood-
Waste Handling based mulches. Its preparation typically does not provide '
Permit or one any weed seed control,so evidence of residual vegexatian in
exempt from solid its composition or lmown inclusion of weed plants or seeds j
` waste regulations. should be monitored and prevented(or m;n;m;�ed). 'I
February 2005 Volume ll—Consfruction Stormwater Pollution Prevention 4-21
BMP C123: Plastic Covering
Purpose Plastic covering provides immediate, short-term erosion protection to
slopes and disturbed areas.
Conditions of • Plastic covering may be used on disturbed areas that require cover
Use measures for less than 30 days, except as stated below.
• Plastic is particularly useful for protecting cut and fill slopes and
stockpiles. Note: The relatively rapid breakdown of most polyethylene
sheeti.ng makes it unsuitable for long-term(greater than six months)
applications.
• Clear plastic sheeting can be used over newly-seeded areas to create a
greenhouse effect and encourage grass growth if the hydroseed was
installed too late in the season to establish 75 percent grass cover, or if
the wet season started earlier than normal. Clear plastic should not be
used for this purpose during the swruner months because the resulting ��
high temperatures can kill the grass.
• Due to rapid runoff caused by plastic sheeting,this method shall not be
used upslope of areas that might be adversely impacted by
concentrated runoff. Such areas include steep and/or unstable slopes.
• While plastic is inexpensive to purchase,the added cost of installation,
maintenance,removal,and disposal make this an expensive material, �.
up to$1.50-2.00 per square yard.
• Whenever plastic is used to protect slopes,water collection measures
must be installed at the base of the slope. These measures include
plastic-covered berms,channels,and pipes used to covey clean
rainwater away from bare soil and disturbed areas. At no time is clean
�
runoff from a plastic covered slope to be mixed with dirty runoff from
a project.
• Other uses for plastic include:
� 1. Temporary ditch liner;
2. Pond liner in temporary sediment pond;
3. Liner for bermed temporary fuel storage azea if plastic is not
reactive to the type of fuel being stored;
t � 4. Emergency slope protection during heavy rains; and,
5. Temporary drainpipe("elephant trunk")used to direct water.
426 Volume!I—Construction Stormwafer.Pollution Prevention February 2005
- � Design and • Plastic slope cover must be installed as follows:
Installation 1. Run plastic up and down slope,not across slope;
Specifications
2. Plastic may be installed perpendicular to a slope if the slope length
is less than 10 feet; �
3. Minimum of 8-inch overlap at seams;
4. On long or wide slopes, or slopes subject to wind, all seams should
be taped;
5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench
at the top of the slope and backfill with soil to keep water from
flowing undemeath;
6. Place sand filled burlap or geote�rtile bags every 3 to 6 feet along
seams and pound a wooden stake throtigh each to hold them in
place;
7. Inspect plastic for rips,tears, and open seams regularly and repair
unmediately. This prevents high velocity runoff from contacti.ng
bare soil which causes extreme erosion;
8. Sandbags may be lowered into place tied to ropes. However, all
sandbags must be staked in place.
i' • Plastic sheeting shall have a miniinnum thickness of 0.06 millimeters.
• If erosion at the toe of a slope is likely, a gravel berm,riprap, or other
suitable protection shall be installed at the toe of the s�ope in order to �
reduce the velocity of runoff.
Maintenance • Tom sheets must be replaced and open seams repaired.
Standards
• If the plastic begins to deteriorate due to ultraviolet radiation, it must I,
be completely removed and replaced. !
• ��Vhen the plastic is no longer needed,it shall be completely removed. i
• Dispose of old tires appropriately. '�,
February 2005 Volume ll— Consfruction Stormwafer PoJlution Prevention 4-27
BMP C150: Materials On Hand �,
Purpose Quantities of erosion prevention and sediment control materials can be �
kept on the project site at all times to be used for emergency situations
• such as unexpected heavy su.mmer rains. Having these materials on-site
reduces the time needed to implement BMPs when inspections indicate
that e�sting BMPs are not meeting the Construction SWPPP
requirements. In addition, contractors can save money by buying some
materials in bulk and stori.ng them at their office or yard.
Conditions of Use • Construction projects of any size or type can benefit from having
materials on hand. A small commercial development project could
have a roll of plastic and some gravel available for immediate
� protection of bare soil and temporary berm construction. A large
earthwork project, such as highway construction,might have several
tons of straw, several rolls of plastic, flexible pipe, sandbags,
geotextile fabric and steel "T"posts.
• Materials are stockpiled and readily available before any site clearing,
grubbing, or earthwork begins. A large contractor or developer could
keep a stockpile of materials that are available to be used on several
projects.
. • If storage space at the project site is at a premium,the contractor could
maintain the materials at their office or yard. The office or yard must
be less than an hour from the project site. �
Design and Depending on project type, size, complexity, and length,materials and '
Installation quantities will vary. A good minimum that will cover numerous situations
Specifications includes:
Material Measure Quanti
Clear Plastic, 6 mil 100 foot roll 1-2
Drain i e, 6 or 8 inch diameter 25 foot section 4-6
Sandb s,filled each 25-50
Straw Bales for mulchin , a rox. 50#each 10-20
S alls ton 2-4
Washed Gravel cubic ard 2-4
Geotextile Fabric 100 foot roll 1-2
Catch Basin Inserts each 2-4
Steel"T"Posts each 12-24
Maintenance • All materials with the exception of the quarry spalls, steel"T"posts,
Standards and gravel should be kept covered and out of both sun and rain.
• Re-stock materials used as rieeded.
4-42 Vo/ume ll—ConstrUcfion Stormwater Pollufion Prevention February 2005
� BMP C151: Concrete Handling
Purpose Concrete work can generate process water and slurty that contain fine
particles and high pH,both of which can violate water quality standards in
the receiving water. This BMI'is intended to minimize and eliminate
concrete process water and slurry from entering waters of the state.
Conditions of Use Any time concrete is used,these management practices shall be utilized.
Concrete construction projects include,but are not limited to,the
following:
• Curbs
• Sidewalks
• Roads
• Bridges
• Foundations
• Eloors
• Runways
Design and • Concrete truck chutes,pumps, and internals shall be washed out only ,
Installation into formed areas awaiting installation of concrete or asphalt.
Specifications Unused concrete remaining in the truck and pump shall be returned to
1 '
g g P y ' g �
the ori inatin batch lant or rec c �
- • Hand tools including,but not limited to, screeds, shovels,rakes, floats, I'�
and trowels shall be washed off only into formed areas awaiting �
' installation of concrete or asphalt. I
• Equipment that cannot be easily moved, such as concrete pavers, shall �
only be washed in areas that do not directly drain to natural or
constructed stormwater conveyances.
• Washdown from areas such as concrete aggregate driveways shall not
drain directly to natural or constructed stormwater conveyances.
• When no formed areas are available,washwater and leftover product
shall be contained in a lined container. Contained concrete shall be
disposed of in a manner that does not violate groundwater or surface
water quality standards.
Maintenance Containers shall be checked for holes in the,li.ner daily during concrete
Standards pours and repaired the same day.
I February 2005 Vo/ume Il— Construction Stormwater Po!lution Prevention 4-43
BMP C152: Sawcutting and Surfacing Pollution Prevention ,
�,
Purpose Sawcutting and surfacing operations generate slurry and process water
that contains fine particles and high pH(concrete cutting),both of which
can violate the water quality standards in the receiving water. This BMP
is intended to minimi7e and eliminate process water and slurry from
enteri.ng waters of the State.
Conditions of Use Anytime sawcutting or surfacing operations take place,these
management practices shall be utilized. Sawcutting and surfacing
operations include,but are not limited to,the following:
• Sawing
• Coring
• Grinding �
• Roughening
• Hydro-demolition �I
• Bridge and road surfacing '
Design and • Slurry and cuttings shall be vacuumed during cutting and surfacing ,
Installation operations. ,
Specifications . Slurry and cuttings sl�all not remain on permanent concrete or asphalt ( I',
pavement overnight. ',
• Slurry and cuttings shall not drain to any natural or constructed
drainage conveyance.
• Collected sluny and cuttings shall be disposed of in a manner that does
not violate groundwater or surface water quality standards.
• Process water that is generated during hydro-demolition, surface
rougheni.ng�r similar operations shall not drain to any natural or
constructed drainage conveyance and shall be disposed of in a manner
that does not violate groundwater or surface water quality standards.
• Cleaning waste material and demolition debris shall be handled and ',
disposed of in a manner that does not cause contamination of water. If ',
the azea is swept with a pick-up sweeper,the material must be hauled I,
out of the area to an appropriate disposal site. li
Maintenance Continually monitor operations to determine whether slurry, cuttings, or
Standards process water could enter waters of the state. If inspections show that a
violation of water quality standards could occur, stop operations and
immediatel�implement preventive measures such as berms,barriers,
secondary containment, and vacuum trucks.
444 Volume 1!- Construction Stormwater Pollufion Prevention February 2005 '
�� BMP C160: Certified Erosion and Sediment Control Lead
Purpose The project proponent designates at least one person as the responsible
representative in charge of erosion and sediment control(ESC), and water
quality protection. The designated person shall be the Certified Erosion
and Sediment Control Lead(CESCL)who is responsible for ensuring
compliance with all local, state,and federal erosion and sediment control
and water quality requirements.
Conditions of Use A CESCL shall be made available on projects one acre or larger that
discharge stormwater to surface waters of the state
• The CESCL shall:
• Have a current certificate proving attendanee in an erosion and
sediment control training course that meets the m;nimum ESC
train.ing and certification requirements established by Ecology
(see details below).
Ecology will maintain a list of ESC training and certification
providers at: «�ww.ecv.wa.aov/pro�ams/wq/stormwater.
OR
. • Be a Certified Professional in Erosion and Sediment Control
t� (CPESC); for additional information go to: www.cpesc.net
Specifications . Certification shall remain valid for three years.
• The CESCL shall have authority to act on behalf of the contractor or
developer and shall be available,on call,24 hours per day throughout
the period of construction.
• The Construction SWPPP shall include the name,telephone number,
fax number, and address of the designated CESCL. _
• A CESCL may provide inspection and compliance services for
multiple construction projects in the same geographic region.
Duties and responsibilities of the CESCL shall include,but aze not limited
to the following: �
• Maintaining permit file on site at all times which includes the SWPPP
and any associated permits and plans.
• Directing BMP installation,inspection,maintenance, modification,
and removal. '
• Updating all project drawings and the Construction SWPPP with
changes made.
February 2005 Volume !I— Construction Stormwafer Po!lution Prevenfion 4-47
• Keeping daily logs, and inspection reports. Inspection reports should �'
include:
•Inspection date/time.
•Weather information; general conditions during inspection and
approximate amount of precipitation since the last inspection.
•A summary or list of all BMPs implemented, including
observations of all erosion/sediment control structures or
practices. The following shall be noted:
. 1)Locations of BMPs inspected,
2)Locations of BMPs that need maintenance,
3)Locations of BMPs that failed to operate as designed or
intended,and
4)Locations of where additional or different BMPs are
� required.
•Visual monitori.ng results, including a description of dischazged
stormwater. The presence of suspended sediment,turbid
water, discoloration, and oil sheen shall be noted, as applicable.
•Any water quality monitori.ng performed during inspection. �
•General comments and notes,including a brief description of any
BMP repairs, maintenance or installations made as a result of
the inspection. �
• Facilitate,participate in, and take corrective actions resulting from
inspections performed by outside agencies or the owner.
¢48 Volume ll—Construction Stormwater Po!lution Prevention February 2005
�
Minimum Requirements for ESC Training and Certification Courses
General Requirements
l. The course shall teach the construction stormwater pollution prevention guidance
provided in the most recent version of:
a. The Washington State Dept. of Ecology Stormwater Management Manual for
� Westem Washington,
b. Other equivalent stormwater management manuals approved by Ecology.
2. Upon completion of course,each attendee shall receive documentation of certification,
including, at a minimum, a wallet-sized card that certifies completion of the course.
Certification shall remain valid for three years.Recertification may be obtained by
completing the 8-hour refresher course or by taking the i.nitial 16-hour training course
again.
3. The i.nitial certification course shall be a minimum of 16 hours(with a reasonable time
allowance for lunch,breaks,and travel to and from field) and include a field element and
test. �
a. The field element must familiarize students with the proper installation,
maintenance and inspection of common erosion and sediment control BMP�s
� — including,but not limited to,blankets, check dams, silt fence, straw mulch,
i'
plastic,and seeding.
b. The test shall be open book and a passing score is not required for certification.
Upon completion of the test,the correct answers shall be provided and discussed ,
4. The refresher course shall be a minimum of 8 hours and include a test.
a. The refresher course shall include:
� i. Applicable updates to the Stormwater Management Manual that is used to i
. teach the course, including new or updated BMPs; and
ii. Applicable changes to the NPDES General Permit for Construction
Activities.
b. The refresher course test shall be open book and a passing score is not required
for certification.Upon completion of the test,the correct answers shall be
provided and discussed.
c. The refresher course may be taught using an alternative format(e.g. intemet, CD
ROM, etc.)if the module is approved by Ecology.
Required Conrse Elements
l. Erosion and Sedimentation Impacts
a. Examples/Case studies
� .
February 2005 Volume 1!—Construction Stormwater Pollution Prevention 4-49
2. Erosion and Sedimentation Processes �
a. Definitions
b. Types of erosion
c. Sedimentation
i. Basic settli.ng concepts
ii. Problems with clays/turbidity
3. Factors Influencing Erosion Potential
a. Soil
. b. Vegetation
c. Topography
d. Climate
4. Regulatory Requirements
a. NPDES - Construction Stormwater General Permit
b. Local requirements and permits
c. Other regulatory requirements
5. Stormwater Pollution Prevention Plan(SWPPP)
a. SWPPP is a living document—should be revised as necessary ,
b. 12 Elements of a SWPPP;discuss suggested BMPs(with examples) '
1. Mark Clearing Limits � �,
2. Establish Construction Access ,
3. Control Flow Rates '
4. Install Sediment Controls
5. Stabilize Soils
6. Protect Slopes
7. Protect Drain Inlets
� 8. Stabilize Channels and Outlets
9. Control Pollutants
10. Control De-watering
1 l. Maintain BMPs
12. Manage the Project
6. Monitoring/Reporting/Recordkeeping
a. Site inspections/visual monitoring �
i. Disturbed azeas
ii. BMPs
ui. Stormwater discharge points
b. Water quality sampling/analysis
i. Turbidity �
ii. pH
. c. Monitori.ng frequency
i. Set by NPDES permit
ii. Inactive sites-reduced frequency
¢50 Volume!!—Consfivction Stormwafer Pollution Prevenfion February 2005
� d. Adaptive Management
i. When monitoring indicates problem,take appropriate action(e.g.
instalUmaintain BMPs)
u. Document the corrective action(s)in SWPPP
e. Reporting
i. Inspection reports/checklists
ii. Discharge Monitoring Reports(DMR)
iii. Non-compliance notification
Instructor Qualifications
1. Instructors must be qualified to effectively teach the required course elements.
2. At a minimum, instructors must have:
a. Current certification as a Certified Professional in Erosion and Sedi.ment Control
(CPESC),ar
b. Completed a traini.ng program for teaching the required course elements, or
c. The academic credentials and instructional experience necessary for teaching the
required course elements.
3. Instructors must demonstrate competent instructional skills and knowledge of the �
_ applicable subject matter. '�
i
i
I
I
February 2005 Volume 11—Construction Stormwater Pollution Prevention 4-51
BMP C162: Scheduling �
Purpose Sequencing a construction project reduces the amount and duration of soil
exposed to erosion by wind,rain, runoff, and vehicle tracking.
Conditions of Use The construction sequence schedule is an orderly listing of all major land-
disturbuig activities together with the necessary erosion and sedimentation
control measures planned for the project. This type of schedule guides the
contractor on work to be done before other worlc is started so that serious
erosion and sedimentation problems can be avoided.
Following a specified work schedule that coordinates the timing of land-
disturbing activities and the installation of control measures is perhaps the
most cost-effective way of controlling erosion during constxuction. The
removal of surface ground cover leaves a site vulnerable to accelerated
erosion. Construction procedures that limit land clearing,provide timely
installation of erosion and sedimentation controls,and restore protective
cover quickly can significantly reduce the erosion potential of a site.
Design � Avoid rainy periods.
Considerations . Schedule projects to disturb only small portions of the site at any one
ti.me. Complete grading as soon as possible. Immediately stabilize the
disturbed portion before grading the ne�portion. Practice staged l
seeding in order to revegetate cut and fill slopes as the work
progresses.
454 Volume ll- Consfrucfion Stormwafer Pollution Prevention February 2005
i
i
� t 4.2 RunofF Conveyance and Treatment BMPs
BMP C200: Interceptor Dike and Swale
� Purpose Provide a ridge of compacted soil, or a ridge with an upslope swale,at the
top or base of a disturbed slope or along the perimeter of a disturbed
construction area to convey stormwater. Use the dike and/or swale to
I intercept the runoff from unprotected areas and direct it to areas where
erosion can be controlled. This can prevent storm runoff from entering the
work area or sediment-laden runoff from leaving the construction site.
` Conditions o,f'Use Where the runoff from an exposed site or disturbed slope must be conveyed
to an erosion control facility which can safely convey the stormwater.
` • Locate upslope of a construction site to prevent runoff from entering
� disiurbed area.
� , • When placed horizontally across a dishubed slope, it reduces the
amount and velocity of runoff flowing down the slope.
• Locate downslope to collect runoff from a disiurbed area and direct it
� to a sediment basin.
Design and • Dike and/or swale and channel must be stabilized with temporary or
Installation permanent vegetation or other channel protection during construction.
tSpecifications . Channel requires a positive grade for drainage; steeper grades require
� channel protectiori and check dams.
� • Review construction for areas where overtoppi.ng may occur.
• Can be used at top of new fill before vegetation is established.
! • May be used as a permanent diversion channel to carry the runoff.
f • Sub-basin tributary area should be one acre or less.
• Design capacity for the peak flow from a 10-year, 24-hour storm,
� ass»min�a Type lA rainfall distribution, for temporary facilities.
Alternatively,use 1.6 times the 10-year, 1-hour flow indicated by an
approved conti.nuous runoff model. For facilities that will also serve
� on a permanent basis, consult the local government's drainage
requirements.
� Interceptor dikes shall meet the following criteria:
Top Width 2 feet minimum, .
Height 1.5 feet minimum on berm.
I . Side Slope 2:1 or flatter.
Grade Depends on topography,however, dike system minimum is
0.5%,ma�imum is 1%.
, � Compaction Minimum of 90 percent ASTM D698 standard proctor. �'I
�
I ,
February 2005 Volume ll—Construction Sformwater PoUufion Prevention 4-57 '�
_ �� BMP C201: Grass-Lined�Channels �
Purpose To provide a channel with a vegetative lining for conveyance of runoff.
See Figure 4.7 for typical grass-lined channels.
Conditions of Use This practice applies to construction sites where concentrated runoff need:
to be contained to prevent erosion or flooding.
• When a vegetative lining can provide sufficient stability for the
channel cross section and at lower velocities of water(normally
dependent on grade). This means that the cha.nnel slopes are generally .
less than 5 percent and space is available for a relatively large cross
section.
• Typical uses include roadside ditches,channels at property boundaries,
outlets for diversions, and other channels and drainage ditches in low
areas. �
• Channels that will be vegetated should be installed before major
. earthwork and hydroseeded with a bonded fiber matr�(BF1Vn. The
vegetation should be well established(i.e., 75 percent cover)before
water is allowed to flow in the ditch. With channels that will have
high�flows,erosion control blankets should be installed over the
hydroseed. If vegetation cannot be established from seed before water
__ is allowed in the ditch, sod should be installed in the bottom of the
�` ditch in lieu of hydromulch and blankets.
; Design and Locate�the channel where it can conform to the topography and other
Installation features such as roads.
I Specifications Locate them to use natural drainage systems to the greatest extent
.
' possible.
• Avoid sharp changes in alignment or bends and cha.nges in grade.
• Do not reshape the landscape to fit the drainage channel.
• The maximum design velocity shall be based on soil conditions,type .
of vegetation,and method of revegeta.tion, but at no ti.mes shall '
velocity exceed 5 feet/second. The channel shall not be overtopped by I
the peak runoff from a 10-year,24-hour storm, assuini.ug a Type lA '�,
rainfall distribution." Alternatively,use 1.6 times the 10-year, 1-hour j
flow indicated by an approved continuous runoff model to determiue a ',
flow rate which the channel must contain. - '',
• Where the grass-lined channel will also function as a permanent I,
stormwater conveyance facility, consultant the dra.inage conveyance �I
requirements of the local government with jurisdiction. i�
• An established grass or vegetated lining is required before the channel ��
can be used to convey stormwater, uniess stabilized with nets or I
, blankets. � "
February 2005 Volume/l— Consfruction Stormwater Polltrfion Prevention 4-59
• If design velocity of a channel to be vegetated by seeding exceeds 2 ;
ft/sec,a temporary channel li.ner is required. Geote�ctile or special �
mulch protection such as fiberglass roving or straw and netting provide
stability until the vegetation is fully established. See Figure 4.9.
• Check dams shall be removed when the grass has matured sufficiently
to protect the ditch or swale unless the slope of the swale is greater
than 4 percent. The area beneath the check dams shall be seeded and
mulched immediately after dam removal.
• If vegetation is established by sodding,the pernussible velocity for
established vegetation may be used and no temporary liner is needed.
• Do not subject grass-lined channel to sedimentation from disturbed
areas. Use sediment-trapping BMPs upstream of the channel.
• V shaped grass channels generally apply where the quantity of water
is small, such as in short reaches along roadsides. The V-shaped cross
section is least desirable because it is difficult to stabilize the bottom
where velocities may be high.
• Trapezoidal grass channels are used where runoff volumes are large
and slope is low so that velocities are nonerosive to vegetated linings.
(Note: it is difficult to construct small parabolic shaped channels.)
. • Subsurface drainage, or riprap channel bottoms, may be necessary on
sites that aze subject to prolonged wet conditions due to long duration
flows or a high water table.
� •. Provide outlet protecrion at culvert ends and at channel intersections.
• Grass channels, at a minimum, should carry peak runoff for temporary
construction drainage facilities from the 10-year, 24-hour storm
without eroding. Where flood hazard exists, increase the capacity
accordi.ng to the potential damage.
• Grassed channel side slopes generally are constructed 3:1 or flatter to
aid in the establishment of vegetation and for maintenance.
• Construct channels a minimum of 0.2 foot larger around the periphery
to allovv for soil bulking duririg seedbed preparations and sod buildup.
Maintenance During the establishment period, check grass-lined channels after every
Standards rainfall.
• After grass is established,periodically check the channel; check it after
every heavy rainfall event. Immediately make repairs.
• It is particulazly important to check the channel outlet and all road
erossings for bank stability and evidence of piping or scour holes.
• Remove all significant sediment accumulations to maintain the
designed carrying capacity. Keep the grass in a healthy,vigorous
condition at all times, since it is the primary erosion protection for the
channel.
4-60 Volume !1- Construction Stormwafer Pollution Prevention February 2005
� Typical V-Shaped Channel Cross-section
`� ,, \��� '� . �, \a �\�
>>� �.�
��,��j'�,�� i�, ��` ^�\�� /�\'� .,��� ��., �//�.
/� `�+rl V��1� //\/, / �,�
.\./.\� i, i t�r �/�\/ -•
/% //\ � n n
����j\��� /�i 6 -9
Filter_�\, /\�/ �150-225mm)
Fabric ���i�/�� Key in Fabric
Grass-Lined �
th Rock Center
Typical Parabolic Channel Cross-Section
UII�/ ���r V,i,i� �..d�l\�
�� '���G;��, ��v`��� �\�'�''��IG,�b 1�a� ���,` ���
�:\ .�` �V�f' '�Vl,� \�1V����v . �/���/ .�/i. / � ,�V� /\�/
\ �'ii I��lil�V� � � 6"-9"�`'� �\\ ��
��\�j\ \ ����•/ (150-225mm) �\ � %�
����j���� Key In Fabric ��// /��/ Filter
� �:'� Fabric
With Channel Liner With Rock Center
� for Base Flow
Typical Trapezoidal Channel Cross-Section
'% � �� � Desi n De th J ^1���� �. ,,�I�
� ✓ 9 P �\ /� // /.
��//�//� ������ \��\
� '��/� /� �
�j\ ���� ' �\ .//��///\/
`�• ' �1/�i ,f�/` .}� 1�' �I 1V�U��d�\�I1.\1�\I� �
vercut channel 2" (50mm)
to allow bulking during �\��\�,�\/�\�j` �\�\��������
seedbed preparation �/���
and grovuth of vegetation. Filter� �Nith Rock Center For Base Flow
Fabric
Figure 4.8—Typical Grass-Lined Channels
February 2005 Volume!!— Consfructron Stormwater Pollution Prevention 4-61
����'r, Overlap 6" (150mm) minimum ���� �
\ i/� y�v \�! '
�� � - ,� Exqvate Channel to Design ��u� �
� �// � �:i Grade and Cross Section `��� � /�///
�, %\\///\ `\/�//��
�� �
��� �� ���i,,�� Design Depth `
��,
OUEHCUTCHANNEL � ��G�� `� Longitudinal
2'(50mmJ TOALLOW '-� ��� anchor trench
BULK/NGOUH/NGSEEDBED f `��� ������ ��I Vi .IL
PHEPAR.4T/ON � \//�/�.//j\///\/�
P
P s•(tsomm) TYPICAL/NSTALLAT/ON
W/TH EROS/ON CONTROL ��/��/
/�/� '� � �� �/ / / BLANKETS OR TUHF � �� ��
//��j j��� :. � j��jj��j RE/NFORCEMENTMATS ��\��\���� �\�\\�\�\�
. \\\%\\\ c somm� \\%\\%\\\ ///\\//\\//�ns�/\//\\///
Intermittent Check Slot Longitudinal Anchor Trench
Shingle-lap spliced ends or begin new ,
� roll in an intermittent check slot
,
� -� �-
Prepare soil and apply seed before � O �
installing blankefs, mats or other u � �
temporary channel liner system � �
� � � �
� � � � . .
� - - - - - - - � � .
, �
. ,,�/\ > \/� .
\��\i� �
�\, /� ��v
/f� ' ��� /\���
\ � \ '
��������%�%��i�/%� ��,
NOTES: �� �\ '
l.Design velocifies exceeding 2 ftlsec(O.Sm/sec)require temporary blankets,mats or similaz
liners to protect seed and soil until vegetation becomes established. '�
2.Grass-lined channels with design velocities exceeding 6 fllsec(2m/sec)should include i�
turf reinforcement mats. �
Figure 4.9—Temporary Channel Liners
4-62 Volume I!—Consfruction Stormwater Pollution Prevention February 2005
,_ �' BMP C202: Channel Lining
Purpose To protect erodible channels by providing a channel liner using either
blankets or riprap.
Conditions of Use When natural soils or vegetated stabilized soils in a channel are not adequat�
to prevent channel erosion.
• When a permanent ditch or pipe system is to be installed and a
temporary measure is needed.
• In almost all cases, synthetic and organic coconut blankets are more
effective than riprap for protecting channels from erosion: Blankets
can be used with and without vegetation. Blanketed channels can be
designed to handle any expected flow and longevity requirement.
Some synthetic blankets have a predicted life span of 50 years or
more, even in sunlight.
• Other reasons why blankets are better than rock include the availability
of blankets over rock. In many areas of the state,rock is not easily
obtainable or is very expensive to haul to a site. Blankets can be
delivered anywhere. Rock requires the use of dump trucks to haul and
heavy equipment to place. Blankets usually only require laborers with
hand tools, and sometimes a backhoe. �
• The Federal Highway Administration recommends not using flexible
(�-- liners whenever the slope exceeds 10 percent or the shear stress
exceeds 81bs/ft2.
Design and See BMP C122 for information on blankets.
Installation Since riprap is used where erosion potential is high, construction must be
Specifications sequenced so that the riprap is put in place with the minimum possible
delay.
• Disturbance of areas where riprap is to be placed should be undertaken
_ only when final preparation and placement of the riprap can follow
immediately behind the initial disturbance. Where riprap is used for
� outlet protection,the riprap should be placed before or in conjunction
_ with the construction of the pipe or channel so that it is in place when
the pipe or channel begins to operate.
' • The designer, after determining the riprap size that will be stable under
� the flow conditions, shall consider that size to be a m;n;mum size and
, then,based on riprap gradations actually available in the area, select
' the size or sizes that equal or exceed the minimum size. The
possibility of drainage structure damage by children shall be
- considered in selecting a riprap size, especially if there is nearby water
or a gully in which to toss the stones.
• Stone for riprap sha11 consist of field stone or quarry stone of
� approximately rectangular shape. The stone shall be hard and angular
and of such quality that it will not disintegrate on exposure to water or
;
February 2005 Volume ll—Construction Sformwater Pollution Prevenfion 4-63
weathering and it shall be suitable in all respects for the purpose i' '
intended.
• Rubble concrete may be used provided it has a density of at least 150
pounds per cubic foot, and otherwise meets the requirement of this
standard and specification.
• A lini.ng of engineeri.ng filter fabric (geotextile) shall be placed
between the riprap and the underlying soil surface to prevent soil
movement into or through the riprap. The geotextile should be keyed
in at the top of the bank. .
• Filter fabrie shall not be used on slopes greater than 1-1/2:1 as slippage
may occur. It should be used 'ui conjunction with a layer of coarse
aggregate (granular filter blanket)when the riprap to be placed is 12
� inches and larger.
4-64 Volume 11—Construction Stormwafer Pollution Prevention February 2005
r BMP C207: Check Dams
;
Purpose Construction of small dams across a swale or ditch reduces the velocity of '
concentrated flow and dissipates energy at the check dam. ',
Conditions of Use �ere temporary channels or permanent channels are not yet vegetated, I
channel lining is infeasible, and velocity checks are required. ,
• Check dams may not be placed in streams unless approved by the State I
Department of Fish and Wildlife. Check dams may not be placed in �
wetlands without approval from a permitting agency. '
• Check dams shall not be placed below the expected backwater from ,
any salmonid bearing water between October 1 and May 31 to ensure '
. that there is no loss of high flow refuge habitat for overwintering �
juvenile salmonids and emergent salmonid fiy.
Design and Whatever material is used,the dam should form a triangle when viewed
Installation from the side. This prevents undercutting as water flows over the face of '
Specifications the dam rather than falling directly onto the ditch bottom.
Check dams in association with sumps work more effectively at slowing �
flow and retaining sediment than just a check dam alone. A deep sump
should be provided 'unmediately upstream of the check dam.
. • In some cases,if carefully located and designed,check dams can
�' remain as permanent installations with very minor regrading. They !
' ma be left as either s illwa s in which case accumulated sediment '
Y P Y �
_ would be graded and seeded, or as check dams to prevent further ,
sediment from leaving the site. �
I • Check dams can be constructed of either rock or ea- avel filled b s. '�
P �' �
Numerous new products are also available for this purpose. They tend !�
to be re-usable,quick and easy to install, effective, and cost efficient. '
_ � • Check da.ms should be placed perpendicular to the flow of water. !i
, • The maximum spacing between the dams shall be such that the toe of ',
, ' the upstream dam is at the same elevation as the top of the downstream ��
` � dam. I
• Keep the ma�mum height at 2 feet at the center of the dam.
• Keep the center of the check dam at lea.st 12 inches lower than the
outer edges at natural ground elevation.
. • Keep the side slopes of the check dam at 2:1 or flatter..
� • Key the stone into the ditch banks and e�rtend it beyond the abutments
a m;n;mum of 18 inches to avoid washouts from overflow around the
dam,
.
February 2005 Volume 11— Consfruction Stormwater Pollution Prevenfion 475
• Use filter fabric foundation under a rock or sand bag check dam. If a �
blanket ditch liner is used,this is not necessary. A piece of organic or
synthetic blanket cut to fit will also work for this purpose.
• Rock check dams shall be constructed of appropriately sized rock.
The rock must be placed by hand or by mechanical means (no
dumping of rock to form dam)to achieve complete coverage of the
ditch or swale and to ensure that the center of the dam is lower than
the edges. The rock used must be large enough to stay in place given
the expected design flow through the channel.
• In the case of grass-lined ditches and swales, all check dams and
accumulated sediment shall be removed when the grass has matured
sufficiently to protect the ditch or swale-unless the slope of the swale
is greater than 4 percent. The area beneath the check dams shall be
seeded and mulched immediately after dam removal.
• Ensure that channel appurtenances, such as culvert entrances below
check dams, are not subject to damage or blockage from displaced
stones. Figure 4.13 depicts a typical rock check dam.
Maintenance Check dams shall be monitored for performance and sediment
Standards accumulation during and after each runoff producing rainfall. Sediment
shall be removed when it reaches one half the sump depth.
• Anticipate submergence and deposition above the check dam and
erosion from high flows around the edges of the dam. `
• If significant erosion occurs between dams, install a protective riprap
liner in that portion of the channel.
4-76 Volume I!— Construction Sformwater Pollution Prevention February 2005
� View Looking Upstream
A 18" (0.5m)
12" (150mm)
�\ \ � ° � /,•'� i�//.��/./
��/i��/i��//��/�o• ��o��o�� Do� °a� ��j��°��' /.
�� /� �0.ov,> po �p4a�q���p� p.o i,.//�/ 24"(0.6m)
NOTE: �'O' �°o�• O. o.
e � � ��� +
<
Key stone into channel banks and � � � /� /
extend it beyond the abutments a ��\� ��\���i\�\�
minimum of 1 S"(0.5m)to prevent A
flow around dam.
Section A - A
FLOW �
24" (0.6m) �o��'��
� O oq o0
0
� g, o 0 00�•
''�//��/��/ � � °ao° , �o�o °o�'o oo,
�/��/�. '� �i� ,/\\ \\ �\��\/�\�\ cp.
.��i\�j��/i������\�j,\��j\��j �j\�j\
\/\/ ��\
8' (2.4m}
Spacing Between Check Dams
'L'=the distance such that points'A'and
'B'are of equal elevation.
'L'
� o ����°gp°� ��POINT'A' �POINT'B'
/��/\�%\��\��\��\� \� \ \ o •
/i�//i.�/�.�/�,�/..�//�/ �/ / �•..,
�\��j��\��\��\��\��\�� �� � ��� ° o n oe
%��j/��j/��j/�//\�//\�//��j,,�/.,�/i /
���\��\���j��j���
NOT TO SCALE
Figure 4.13—Check Dams
February 2005 Volume!1— Consfruction Stormwater Po!lution Prevention 4-77
BMP C209: Outlet Protection � I
Purpose Outlet protection prevents scour at conveyance outlets and m�n�m»es the
potential for downstream erosion by reducing the velocity of concentrated
stormwater flows. �
Conditions of use Outlet protection is required at the outlets of all ponds,pipes, ditches,or
other conveyances, and where runoff is conveyed to a natural or manmade
drainage feature such as a stream,wetland, lake, or ditch.
Design and The receiving channel at the outlet of a culvert shall be protected from
Installation erosion by rock lining a minimum of 6 feet downstream and e�rtending up
Specifications �e channel sides a minimum of 1-foot above the maximum tailwater
elevation or 1-foot above the crown,whichever is higher. For large pipes
(more than 18 inches in diameter),the outlet protection lining of the
channel is lengthened to four times the diameter of the culvert.
: Standard wingwalls, and tapered outlets and paved channels should
also be considered when appropriate for permanent culvert outlet
protection. (See WSDOT Hydraulic Manual, available through �
WSDOT Engineering Publications).
• Organic or synthetic erosion blankets,with or without vegetation, are
usually more effective than rock,cheaper, and easier to install. -
Materials can be chosen using manufacturer product specifications. '
ASTM test results are available for most products and the designer can
choose the conect material for the expected flow.
� • With low flows,vegetation(including sod) can be effective.
• The following guidelines shall be used for riprap outlet protection:
1. If the dischazge velocity at the outlet is less than 5 fps{pipe slope
less than 1 percent),use 2-inch to 8-inch riprap. Minimum
thickness is 1-foot.
2. For 5 to 10 fps discharge velocity at the outlet(pipe slope less than
3 percent), use 24-inch to 4-foot riprap. Minimum thickness is 2
feet.
3. For outlets at the base of steep slope pipes(pipe slope greater than
10 percent), an engineered energy dissipater shall be used.
• Filter fabric or erosion control blankets should always be used under
riprap to prevent scour and channel erosion.
• New pipe outfalls can provide an opportunity for low-cost fish habitat
improvements. For example,an alcove of low-velocity water can be
created by constructing the pipe outfall and associated energy
dissipater back from the stream edge and digging a channel, over- .
widened to the upstreaan side,from the outfall. Overwintering juvenile
and migrating adult salmonids may use the alcove as shelter during
9-80 Volume!I-Construction Stormwater Pol/ution Prevention February 2005
J
� high flows. Bank stabilization,bioengineering, and habitat features �
may be required for disturbed areas. See Volume V for more
- information on outfall system design.
Maintenance . �spect and repair as needed.
Standards
� Add rock as needed to maintain the intended function.
' • Clean energy dissipater if sediment builds up.
�
�
, 1 .
! i �
(
� �
February 2005 Volume 1!— Construction Sformwafer Pollution Prevention 4-81
�
�
� BMP C220: Storm Drain Inlet Protection . �
Purpose To prevent coasse sediment from entering drainage systems prior to
permanent stabilization of the disturbed area.
' Conditions of Use ��Vhere storm drain inlets are to be made operational before permanent
� stabilization of the disturbed drainage area. Protection should be provided
for all storm drain inlets downslope and within 500 feet of a disturbed or
construction area,unless the runoff that enters the catch basin will be
conveyed to a sediment pond or trap. Inlet protection may be used
' anywhere to protect the drainage system. It is likely that the drainage
system will still require cleanirig.
� Table 4.91ists several options for inlet protection. All of the methods for
storm drain inlet protection are prone to plugging and require a high
frequency of maintenance. Drainage areas should be limited to 1 acre or
� less. Emergency overflows may be required where stormwater ponding
would cause a hazard. If an emergency overflow is provided, additional
end-of-pipe treahnent may be required. ,
, Table 4.9
Storm Drain Inlet Profetion
� Applicable for
Type of Inlet Emergency Pavedl Earthen
Protection Overflow Surfaces Conditions of Use
Dro Inlet Protection �
� Excavated drop i.nlet Yes, Earthen Applicable for heavy flows. Easy
protection temporary to mai.ntain. Large area
flooding will Requirement: 30'X 30'/acre
� occur
Block and gravel drop Yes Paved or Earthen Applicable for heavy concentrated
i.nlet protection flows. Will not pond.
Gravel and wire drop No Applicable for heavy concentrated
� inlet protection flows. Will pond. Can withstand
traffic.
Catch basin filters Yes Paved or Earthen Fre uent maintenance re uired.
I Curb Inlet Protection
Curb inlet protection Small capacity Paved Used for sturdy, more compact
with a wooden weir overflow installataon.
� Block and gravel curb Yes Paved Sturdy,but limited filtration.
i.nlet protection
Culvert Inlet Protection
, Culvert inlet sediment 18 month expected life.
tra
1
�
II .
¢82 Volume 11- Constnrction Stormwafer Pollufion Prevention February 2005
Catchbasin Filters-Inserts should be designed by the manufacturer for
{ use at construction sites. The limited sediment storage capacity increases
the amount of inspection and maintenance required,which may be daily
for heavy sediment loads. The maintenance requirements can be reduced
by combining a catchbasin filter with another type of inlet protection.
This type of inlet protection provides flow bypass without overflow and
therefore may be a better method for inlets located along active rights-of-
way.
• 5 cubic feet of storage.
• Dewatering provisions.
� • High-flow bypass that will not clog under normal use at a construction
j site.
• The catchbasin filter is inserted in the catchbasin just below the
grating.
Curb Inlet Protection with �Pooden Weir—Barrier formed around a curb
i.nlet with a wooden frame and gravel.
• Wire mesh with 1/2-inch openings.
• Extra strength filter cloth.
• Construct a frame. ;
• Attach the wire and filter fabric to the frame. '
j� • Pile coarse washed aggregate against wire/fabric.
� • Place weight on frame anchors.
' Block and Gravel Curb Inlet Protection—Barrier formed around an inlet
with concrete blocks and gravel. See Figure 4.14.
• Wire mesh with %z-inch openings.
• Place two concrete blocks on their sides abutting the curb at either side
of the i.nlet opening. These are spacer blocks.
• Place a 2x4 stud through the outer holes of each spacer block to al�gn
the front blocks.
• Place blocks on their sides across the front of the i.nlet and abutting the
spacer blocks.
• Place wire mesh over the outside vertical face.
• Pile coarse aggregate against the wire to the top of the barrier.
Curb and Gutter Sediment Barrier—Sandbag or rock berm(riprap and
aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See Figure
4.16.
• Construct a horseshoe shaped berm, faced with coazse aggregate if
using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inle�
, • Construct a horseshoe shaped sedimentation trap on the outside of the
�� berm sized to sedimen�trap standards for protecting a culvert i.nlet.
February 2005 Volume N—Constrvction Stormwafer Pollution Prevention 4-85
Maintenance • Catch basin filters should be inspected frequently, especially after i
Standards storm events. If the insert becomes clogged, it should be cleaned or
replaced.
• For systems using stone filters: If the stone filter becomes clogged
with sedi.ment,the stones must be pulled away from the inlet and
cleaned or replaced. Since cleani.ng of gravel at a construction site
may be difficult, an alternative approach would be to use the clogged
stone as fill and put fresh stone around the inlet.
• Do not wash sediment into storm drains while cleaning. Spread all
excavated material evenly over the surrounding land area or stockpile
and stabilize as appropriate.
4-86 Vo/ume 1I—Construction Stormwater Pollution Pr�vention February 2005
, . �, Plan View . '
Back of Sidewalk A Catch gasin III
� �
�c4 V1bod Stud
Back of Curb Concrete Block
Curb Inlet
'__' ' G a�,�� Q �'?�'�,.�
.a � e�����
�� � 4�?(���0 d 3�•
� a A�
� q0��• ����
,... P�O o��a eb Q ��° o' �'
.- . .a�^' L��&f�Qo 'R � °R op R 4 p°8�Qd-�����t
�,'�o, o. � •o. o. oA o•o. og, o.a�CpA�op bP
...��, � ,"�'�?°�•4� .Y �� •��Q �`o� ,�°�.�°°s,��p�'�o�� .
_ qop opo.�, op. gop�op���oqoQ�o.Q� op�'op��oop�o.Q�rqop.
v�o, o, �° o o•o oe ae obo",�� �� �� Qo' �^9,SJo�$'
_ ���?�"p� g� �°�� �°�� •��fi��`°o�,.
�
0
� , Wire Screen r
; Filter Fabric A Concrete Block
;
' SeCt��n /�i - A s/•"Dra'n Gravel
� � (20mm) �
' '/."Drain Gravel
(20mm)
Ponding Height
. Concrete Block
OverFl
• • . � �
����\���
'� � Curb inlet �//\
1Mre Screen or \\�/.���%�/\�/\/\ ����
Flter Fabric ����/���i�� //�
4 V1bod Stud �\ Catch Basin \/'
(100x50 Timber Stud) \�
��/
NOTES:
�- 1. Use block and gravel type sedimerrt barrier when curb inlet is locabed in geriUy sloping street segmerrt,
where water can pond and allow sedimer�t to separate from nmoff.
2.Barrier shall aliow for overflow from severe storm everit.
I __
3. Inspect barriers and remove sedimerrt after each stortn event. Sedimerrt and gravel must be removed
from the traveled way immediately.
+ Figure 4.15-Block and Gravel Curb Inlet Protection
February 2005 Volume lf-Construction Stormwater Pollution Prevention 4-87
Plan View � I!�
Back of Sidewalk
Burlap Sacks to Catch Basin
Overlap onto Curb
Curb Inlet
Back of Curb
�
I
I
RUNOFF 'I
RUNOFF SPILLWAY II
_ .
Gravel Filled Sandbags I
Stacked Tightly
'' NOTES:
1.Place curb type sediment barriers on gently sloping street segments,where water can pond and allow
sediment to separa.te from runoff. '
2. Sandbags of either b�slap or woven'geotextile'fabric,are filled with gravel,layered and packed tightly. ��
� 3.Leave a one sandbag gap in the top row to provide a spillway for overflow. j
4.Inspect bazriers and remove sediment after each storm event.Sediment and gravel must be removed from 'i
the traveled way immediately.
Fi ure 4.16—Curb and Gutter Barrier
4-88 Volume I!—Construction Stormwater Pollution PreventioQ February 2005
� BMP C230: Straw Bale Barrier
Purpose To decrease the velocity of sheet flows and intercept and detain small
amounts of sediment from disturbed areas of lixnited extent,preventing
sediment from leaving the site. See Figure 4.17 for details on straw bale
barriers.
Conditions of Use Below disiurbed areas subject to sheet and rill erosion.
' . • Straw bales are among the most used and least effective BMPs. The
best use of a straw bale is hand spread on the site.
• Where the size of the drainage area is no greater than 1/4 acre per 100
feet of barrier length;the maximum slope length behind the barrier is
100 feet;and the maximum slope gradient behind the barrier is 2:1.
• Where effectiveness is required for less than three months.
• Under no circumstances should straw bale barriers be constructed
in streams,channels,or ditches.
• Straw bale barriers should not be used where rock or hard surfaces
prevent the full and uniform anchoring of the barrier.
Design and Bales shall be placed in a single row, lengthwise on the contour,with ends
Installation of adjacent bales tightly abutting one another.
Specifications All bales shall be either wire-bound or string-tied. Straw bales shall be ,
installed so that bindings are oriented around the sides rather than along '
� the tops and bottoms of the bales in order to prevent deterioration of the
bindings.
• The barrier shall be entrenched and backfilled. A trench shall be
� excavated the width of a bale and the Iength of the proposed barrier to
a minimum depth of 4 inches. The trench must be deep enough to
remove all grass and other material that might allow underflow. After
the bales are staked and chi.nked(filled by wedging),the excavated
soil shall be backfilled against the barrier. Backfill soil shall conform
to the ground level on the downhill side and shall be built up to 4
inches against the uphill side of the barrier.
• Each bale shall be securely anchored by at least two stakes or re-bars
driven through the bale. The first stake in each bale shall be driven
toward the previously laid bale to force the bales together. Stakes or
re-bars shall be driven deep enough into the ground to securely anchor
the bales. Stakes should not extend above the bales but instead should
be driven in flush with the top of the bale for safety reasons.
� • The gaps between the bales shall be chinked(filled by wedging)with
straw to prevent water from escaping between the bales. Loose straw
scattered over the area immediately uphill from a straw bale barrier
tends to increase barrier efficiency. Wedging must be done carefully
in order not to separate the bales.
i
Febrr�ary 2005 Volume ll—Construction Sformwater Pollution Prevention 4-89
Maintenance • Straw bale barriers shall be inspected immediately after each runoff- �
Standards producing rainfall and at least daily during prolonged rainfall.
• Close attention shall be paid to the repair of da.maged bales,end runs,
and undercutting beneath bales.
• Necessary repairs to barriers or replacement of bales shall be
accomplished promptly.
• Sediment deposits should be reinoved after each runoff-producing
rainfall. They must be removed when the level of deposition reaches
appro�mately one-half the height of the barrier. .
• Any sediment deposits remaining in place after the straw bale barrier
is no longer requued shall be dressed to conform to the existing grade,
. prepared and seeded
• Straw bales used as a temporary straw bale barrier shall be removed
after project completion and stabilization to prevent sprouting of
unwanted vegetation.
4-90 Volume!I— Construction Stormwater Pollution Prevention February 2005
j ,
�� �
Section A - A
5'-6'
(1.5-1.8m) ��\/ / ' \/�\/\\
�jj/,///\ %/,.//��/�
Ponding Height
2�� S\o/��
\ \ \\/\\//\\//\���� Embed Straw Bale
4"(100mm)Minimum
�////� into Soil
.
Angle Stake Toward
Previous Bale to
Section B - B A Provide Tight Fit
,, , , ,
% i, � i . % A ,, i. � . . i �/
Wooden 5take
or Rebar Driven
� Through Bale.
Pian ��` LL �
/
B B
v
NOTES:
1.The straw bales shall be placed on slope contour.
2.Bales to be placed in a row with the ends tightly abutting.
3.Key in bales to prevent erosion or flow under bales.
Figure 4.17 Straw Bale Barrier
r �
February 2005 Volume II— Consfruction Stormwater PolJution Prevention 4-99
BMP C233: Silt Fence I
Purpose Use of a silt fence reduces the transport of coarse sedi.ment from a
construction site by providing a temporary physical barrier to sediment
and reducing the runoff•velocities of overland flow. See Figure 4.19 for '
details on silt fence construction.
Conditions of llse Silt fence may be used downslope of all disturbed areas.
• Silt fence is not intended to treat concentrated flows,nor is it intended
to treat substantial amounts of overland flow. Any concentrated flows
must be conveyed through the drainage system to a sedi.ment pond.
The only circumstance in which overland flow can be treated solely by
a silt fence,rather than by a sediment pond, is when the area drai.ning
to the fence is one acre or less and flow rates are less than 0.5 cfs..
• Silt fences should not be constructed in streams or used in V-shaped
ditches. They are not an adequate method of silt control for anything
deeper than sheet or overland flow.
Joints in fifter fabric shall be spliced at
posts.Use staples,wire rings or 2"x2•by 14 Ga.wire or
equivalent to attach fabric to posts equivalent 'rf standard
� strength�abric used
� � Filter fabric
II I =
II I N �
II I
II
��� �� � � � c
� 7 �.-6'max-� T� Minimum 4"x4"trench � E
!J �, , "
Backfill trench with native soil
' Post spacing may be increased or 3/4"-1.5"washed gravel
to 8'if wire backing is used
2'x2"wood posts,steei fence
posts,or equivalent
Figure 4.19—Silt Fence
Design and • Drainage area of 1 acre or less or in combination with sediment basin
Installation in a larger site.
Speci.f'tcations
• Maximum slope steepness (normal(perpendiculaz)to fence line) 1:1.
• Maximum sheet or overland flow path length to the fence of 100 feet.
• No flows greater than 0.5 cfs.
• The geotextile used shall meet the following standa.rds. All geotextile
properties listed below are m;nimum average roll values(i.e.,the test
result for any sampled roll in a lot shall meet or exceed the values �
shown in Table 4.10):
494 Vo/ume/l—Consfruction Stormwater Pollution Prevention February 2005
Table 4.10
�, Geotextile Standards
Polymeric Mesh AOS 0.60 mm ma�cimum for slit film wovens(,#30 sieve). 0.30
(ASTM D4751) mm maximum for all other geotextile types(#50 sieve).
' 0.15 mm min;mum for all fabric types(#100 sieve).
Water Permittivity 0.02 sec m;n;mum
(ASTM D4491)
Grab Tensile Strength 1801bs.Mi.nimum for exh�a strength fabric.
(ASTM D4632) 1001bs min;T„um for standard strength fabric.
Grab Tensile Strength 30%maximum
(ASTM D4632)
Ultraviolet Resistance 70%min;mum
(ASTM D4355)
. • Standard strength fabrics shall be supported with wire mesh, chicken
wire, 2-inch x 2-inch wire, safety fence, or jute mesh to increase the
strength of the fabric. Silt fence materials are available that have
• synthetic mesh backing attached �
• Filter fabric material shall contain ultraviolet ray inhibitors and
stabilizers to provide a minimum of six months of expected usable
construction life at a temperahue range of 0°F.to 120°F.
• 100 percent biodegradable silt fence is available that is strong,long
lasting,and can be left in place after the project is completed,if
permitted by local regulations.
• Standard Notes for construction plans and specifications follow. Refer
to Figure 4.19 for standard silt fence details. ',
The contractor shall install and maintain temporary silt fences at the j
locations shown in the Plans. The silt fences shall be constructed in I
the areas of clearing, grading,or drainage prior to starting those �
, activities. A silt fence shall not be considered temporary if the silt
fence must function beyond the life of the contract. The silt fence
shall prevent soil carried by runoff water from going beneath,through, �
or over the top of the silt fence,but shall allow the water to pass
through the fence. '
The m;nimum height of the top of silt fence shall be 2 feet and the
m�.Ximum height shall be 21/z feet above the original ground surface.
The geote�ctile shall be sewn together at the point of manufacture, or at
an approved location as determined by the Engineer,to form geotextile
lengths as required. All sewn seams shall be located at a support post. ,
Alternatively,two sections of silt fence can be overlapped,provided ',
the Contractor can demonstrate,to the satisfaction of the Engineer,that '
the overlap is long enough and that the adjacent fence sections are
close enough together to prevent silt laden water from escaping
through the fence at the overlap.
February 2005 Vo/ume H—Consfruction Stormwater Pollution Prevention 4-95
The geotextile shall be attached on the up-slope side of the posts and
. support system with staples,wire, or in accordance with the
manufacturer's recommendations. The geote�rtile shall be attached to
the posts in a manner that reduces the potential for geotextile tearing at
the staples;wire, or other connection device. Silt fence back-up
support for the geotextile in the form of a wire or plastic mesh is
dependent on the properties of the geotextile selected for use. If wire
or plastic back-up mesh is used,the mesh shall be fastened securely to
the up-slope of the posts with the geotextile being up-slope of the
mesh back-up support.
The geote�ile at the bottom of the fence shall be buried in a trench to
a minimum depth of 4 inches below the ground surface. The trench
shall be backfilled and the soil tamped in place over the buried portion
of the geotextile, such that no flow can pass beneath the fence and
scouring can not occur. When wire or polymeric back-up support
mesh is used,the wire or polymeric mesh shall extend into the trench a
minimum of 3 inches.
The fence posts shall be placed or driven a minimum of 18 inches. A
m;nimum depth of 12 inches is allowed if topsoil or other soft
subgrade soil is not present and a minimum depth of 18 inches cannot
be reached. Fence post depths shall be increased by 6 inehes if the
fence is located on slopes of 3:1 or steeper and the slope is
perpendicular to the fence. If required post depths cannot be obtained,
the posts shall be adequately secured by braci.ng or guying to prevent .
overiurning of the fence due to sediment loading.
Silt fences shall be located on contour as much as possible, except at
the ends of the fence,where the fence shall be turned uphill such that
the silt fence captures the ninoffwater and prevents water from
flowing around the end of the fence.
If the fence must cross contours,with the exception of the ends of the
fence,gravel check dams placed perpendicular to the back of the fence
shall be used to m;nimi�e concentrated flow and erosion along the
back of the fence. The gravel check dams shall be approxi.mately 1-
foot deep at the back of the fence. It shall be continued perpendicular
to the fence at the same elevation until the top of the check dam
intercepts the ground surface behind the fence. The gravel check dams
shall consist of crushed surfacing base course, gravel backfill for
walls, or shoulder ballast. The gravel check dams shall be located
. every 10 feet along the fence where the fence must cross contours.
The slope of the fence line where contours must be crossed shall not
be steeper tha.n 3:1.
Wood, steel or equivalent posts shall be used Wood posts shall have
minimum dimensions of 2 inches by 2 inches by 3 feet minimum
length,and shall be free of defects such as�ots, splits, or gouges.
4-96 Volume 11—Consfruction Stormwater Po/lufion Prevention February 2005
Steel posts shall consist of either size No. 6 rebar or larger, ASTM A
� 120 steel pipe with a uLinimum diameter of 1-inch, U,T,L, oi C shape
steel posts with a minimum weight of 1.351bs./ft. or other steel posts
having equivalent strength and bending resistance to the post sizes
listed The spacing of the support posts shall be a maximum of 6 feet.
Fence back-up support, if used, shall consist of steel wire with a
maximum mesh spacing of 2 inches,or a prefabricated polymeric
mesh. The strength of the wire or polymeric mesh shall be equivalent
to or greater than 1801bs. grab tensile strength. The polymeric mesh
. must be as resistan�to ultraviolet radiation as the geote�rtile it supports.
� Silt fence installation using the slicing method specification details
follow. Refer to Figure 4.20 for slicing method details.
The base of both end posts must be at least 2 to 4 inches above the top
of the silt fence fabric on the middle posts for ditch checks to drain
properly. Use a hand level or string level, if necessary,to mark base
points before installation.
Install posts 3 to 4 feet apart in critical retention areas and 6 to 7 feet
apart in standard applications.
Install posts 24 inches deep on the downstream side of the silt fence,
and as close as possible to the fabric, enabling posts to support the
__ fabric from upstream water pressure.
� Install posts with the nipples facing away from the silt fence fabric.
Attach the fabric to each post with three ties, all spaced within the top
8 inches of the fabric. Attach each tie d.iagonally 45 degrees through
the fabric,with each puncture at least 1 inch vertically apart. In '
addition,each tie should be positioned to hang on a post nipple when
tightening to prevent saggi.ng.
Wrap appro�mately 6 inches of fabric around the end posts and secure
with 3 ties. �
No more than 24 inches of a 36-inch fabric is allowed above ground
level.
The rope lock system must be used in all ditch check applications.
The installation should be checked and corrected for any deviation I,
before compaction. Use a flat-bladed shovel to tuck fabric deeper into '
the ground if necessary.
Compaction is vitally important for effective results. Compact the soil
immediately next to the silt fence fabric with the front wheel of the
tractor, skid steer, or roller exerting at least 60 pounds per square inch.
Compact the upstream side first and then each side twice for a total of
four trips.
� �
February 2005 Volume ll-Consfruction Stornrwater Pollufion Prevention 4-97
• Any damage shall be repaired immediately.
Maintenance �
• If concentrated flows are evident uphill of the fence,they must be
Standards intercepted and conveyed to.a sediment pond.
• It is important to check the uphill side of the fence for signs of the
fence clogging and acting as a barrier to flow and then causing
channelization of flows parallel to the fence. If this occurs,replace the
fence or remove the trapped sediment.
• Sediment deposits shall either be removed when the deposit reaches
approximately one-third the height of the silt fence, or a second silt
fence shall be installed.
• If the filter fabric (geotextile)has deteriorated due to ultraviolet
breakdown,it shall be re laced.
-.,;
_ ,,.
iu.dlay i�.iyhe POET SPAGtMG: .
ma�c 2T T a��[.�a ep�n nma . _
.............. .. '....«:........TopdFaWie
. r asax.oa pesGnB anat ' � ,:
Attub Me1e ta f - .. � ''r
. nn:am.u.ar o.�
, - �g'^�,
FLO1R—+ .
" o.w'�o►.r sseh rt�N r � POST QEPTH: �
sxt faea s b t ate.a b enueb MEew�rwnd `.
�rtri dwl�� � as taisEe ab�rr Oreea�0 `
•O ps.i.�s ps�h� } ,.. ... ' '
. SOD%tewpaetlo�. 1Do%wepsee�n . .�aa.d����nn_1n.
�\��\�/� \��\/�\���\�//�\ ---_
/\;\\\�\\\ \�\\�,\�\\/�\\ —
//�/� /�/�� //\/�\/,\�`\ _
///;/j\%�{ ����j�\��j�\��j/�� n�r�ucw�r a�ua�
�/��j� � \%��i`\�\�\\� •Gau,er reene a pom�,r.iesdee.
�\ \ � r \/�/�/ �/
��\\�/\�/\�/ �'.Q�%���\���`\\ •ut�'¢e tltiee Sespa posl,all wWn tq�8•d feMc
. /\�/��/\! �`��������� •RdRlon satll tie�apmdy:punalM4q hdlS.r�I�sCy.-��`
%/��/�/ �i �%�%�%�% a e�+4+Ynse ot T apsm .
\ �� \ � \��\t�\\\� _ _
•Hag wch 8s on a P�MFF+M�MD��•. ;
No more than 24'of a 3S'tahric ws�ws eec�md ar ad�,.�ae.,
is allowad above grotn►d. -
Roi af s+lt teaee
,� � ,�_,.� .
�
� -
. . �
��
. �c; ., . Fa[�Ac'
a6a�: Sit f�ee
��
k���# v`r�'��? �`�✓,o-�,;
i q,C�3`����'� .:i� �. 1 y�v,�%`�J:.; y{�.�
i � �d.�i�i' �. � .� � r;N:;� �A�'��,
.� ��\, �jt��/�b" �\/ ,�.� .\i\J;` ���/
,�`f r� Q<a.f!�' . i�.' . `�.,<.
C?��,�����\�l���'i��i� ✓ii.b�h�\ `�`/`t9,.�y .. . � .'ri �i,, .�.
o.. v.�� ��e`a � `� a� � . �:' � ��� �i\!i
�
1k+�anoet c�sel P�n 9cing blade;.
�75 mm wt�l�j (t B mm wldlh}:: •
� Coa�plaosd kmdatlon
,.. . ,..
t�ptow 8 nat ac�trile becsuse oF. : "
Figure 4.20-Silt Fence Installation by Slicing Method
4-98 Volume I!- Construction Stormwafer Pollution Prevention February 2005
BMP C240: Sediment Trap ,
Purpose A sediment trap is a small temporary ponding area with a gravel outlet
used to collect and store sedi.ment from sites cleared andlor graded during
construction. Sediment traps,along with other peri.meter controls, shall be �
installed before any land disturbance takes place in the drainage area.
Conditions of Use Prior to leaving a construction site, stormwater runoff must pass through a
sediment pond or trap or other appropriate sediment removal best
management practice. Non-engineered sediment traps may be used on-site
� prior to an engineered sediment trap or sediment pond to provide
additional sediment removal capacity.
. It is intended for use on sites where the tributary drainage area is less than
3 acres,with no unusual drainage features, and a projected build-out time
of six months or less. The sediment trap is a temporary measure(with a
design life of approximately 6 months) and shall be maintained until the
site area is permanently protected against erosion by vegetation and/or
structures.
' Sediment traps and ponds are only effective in removing sediment down
to about the medium silt size fraction. Runoffwith sediment of finer
grades (fine silt and clay)will pass through untreated, emphasizing the
need to control erosion to the ma�umum e�ent first.
i
Whenever possible, sedi.ment-laden water shall be discharged into onsite,
relatively level,vegetated areas (see BMP C234-Vegetated Strip). This
is the only way to effectively remove fine particles from iunoff unless
chemical treatment or filtration is used. This can be particularly useful
after initial treatment in a sediment trap or pond. The areas of release
must be evaluated on a site-by-site basis in order to determine appropriate
locations for and methods of releasing runoff. Vegetated wetlands shall
not be used for this purpose. Frequently, it may be possible to pump water
from the collection point at the downhill end of the site to an upslope
vegetated area. Pumping shall only augment the treatment system,not
replace it,because of the possibility of pump failure or runoff volume in
excess of pump capacity.
All projects that aze constructing permanent facilities for runoff quantity
control should use the rough-graded or final-graded permanent facilities
for traps and ponds. This includes combined facilities and infiltration
facilities. When permanent facilities are used as temporary sedimentation
facilities,the surface area requirement of a sediment trap or pond must be
met. If the surface area requirements are larger than the surface area of
the permanent facility,then the trap or pond shall be enlarged to comply
with the surface azea requiremen� The permanent pond shall also be
divided into two cells as required for sediment ponds.
4-102 Volume!1— Construction Stormwater Pollution Prevention February 2005
Either a permanent control structure or the temporary control structure
� (described in BMP C241, Temporary Sediment Pond)can be used. If a
permanent control structure is used, it may be advisable to partially restrict
the lower orifice with gravel to increase residence time while still allowing
dewatering of the pond. A shut-off valve may be added to the control
structure to allow complete retention of stormwater in emergency
situations. In this case, an emergency overflow weir must be added.
A skimmer may be used for the sediment trap outlet if approved by the
Local Permittin�Authority.
Design and • See Figures 4.22 and 4.23 for details.
Installation . If permanent runoff control facilities are part of the project,they
Specifications
should be used for sediment retention.
• To determi.ne the sediment trap geometry,first calculate the design
surface area(SA) of the trap,measured at the invert of the weir. Use
the following equation:
SA = FS(Q�JVS)
where
Q2 = Design inflow based on the peak discharge from the
-- developed 2-year runoff event from the contributing
i � drainage area as computed in the hydrologic analysis. The
10-year peak flow shall be used if the project size,expected
timing and duration of construction,or downstream
conditions warrant a higher level of protection. If no
hydrologic analysis is required,the Rational Method may
be used.
VS = The settling velocity of the soil particle of interest. The
0.02 mm(medium silt)particle with an assumed density of
2.65 g/cm3 has been selected as the particle of interest and
has a settling velocity(Vs)of 0.00096 f�Jsec.
FS = A safety factor of 2 to account for non-ideal settling.
Therefore,the equation for computing surface area becomes:
5A = 2 x Q�0.00096 or
I2080 square feet per cfs of i.nflow
Note:Even if permanent facilities are used,they must still have a
surface area that is at least as large as that derived from the above
formula. If they do not,the pond must be enlarged.
• To aid in determining sediment depth, all sediment traps shall have a
� staff gauge with a prominent mark 1-foot above the bottom of the trap.
I � February 2005 Vo/ume!I-Construcfion Stormwater Pollution Prevention 4-103
• Sediment traps may not be feasible on utility projects due to the ;
� limited work space or the short-term nature of the work. Portable
� tanks may be used in place of sediment traps for utility projects.
Maintenance • Sediment shall be removed from the trap when it reaches 1-foot in
Standards depth.
• Any damage to the pond embank�ents or slopes shall be repaired.
SurFace area determined 4'Min. �
at top of weir
� � � � _ � s � � � � 1' Min. Ovelrflow
�y � 1`Mn. `��—
�L 3.5'-5' 1' Min.
� 1.5'Min. �
�' Flat Bottom
o/�,_1.5�� 2,��,�R� R�p�P
Vlfashed gravel
Note:Trap may be formed by berm or by Geotextile
partial or complete excavation
Discharge to stabilized
conveyance,outlet,or
level spreader
Figure 4.22 Cross Section of Sediment Trap
6' Min:
_�������_���_���=I�I_)� 1'Min. depth overflow spiliway —I I I—I I I—I I I—I I I—I I�I
ii=i i i-i i i-i i i-iTi-1 I 1=1 I I 1=�Ti-iTi-i i i-i i i-i i i_
��IIIII II- p
Native soil or Min. 1' de th
compacted bacl�ill ��.��� ' '• ' _���- 2"-4'"rodc
Geotextile -I I I—I I�_���_������—���_��� ���_����� Min. 1'depth 3/4"-1.5" '
=���=���,-������ ������ ������� washed gravel
Figure 4.23 Sediment Trap Outlet
4-104 Volume!1–Constnrcfion Sformwater Poliution Prevenfion February 2005
Stormwater Pollution Prevention Plan '
Appendix C — Alternative BMPs '
No alternative BMP's are proposed for the project.
29
Stormwater Po/lution Prevention Plan
Appendix D — General Permit
31
Issuance Date: November 16, 2005
Effective Date: December 16, 2005
Expiration Date: December 16, 2010
CONSTRUCTION STOF�MWATER GENERAL PERMIT
National Pollutant Discharge Elimination System (NPDES) and State Waste
Discharge General Permit for Stormwater Discharges Associated With
Construction Activity
State of Washington
Department of Ecology
Olympia, Washington 98504-7600
In compliance with the provisions of
The State of Washington Water Pollution Control Law
Chapter 90.48 Revised Code of Washington
and
The Federal Water Pollution Control Act
(The Clean Water Act)
Title 33 United States Code, Section 1251 et seq.
Until this pernut expires, is modified or revoked, Permittees that have properly obtained
coverage under this general permit are authorized to discharge in accordance with the special and
general conditions which follow.
��
David C.Peeler, Manager
Water Quality Program
Washington State Department of Ecology
�
Page 2 of 46
TABLE OF CONTENTS
SUMMARY OF PERMIT REPORT SUBMITTALS.....................................................................3
SUMIVIARY OF REQUIRED ON SITE DOCUMENTATION....................................................3
SPECIAL CONDITIONS
S1. PERNIIT COVERAGE........................................................................................................4
S3. COMPLIANCE WITH STANDARDS...............................................................................9
S4. MO1vITORING REQUIREMENTS..................................................................................10
S5. REPORTING AND RECORDKEEPING REQIJIRENIENTS.........................................15
S6. PERNIIT FEES...................................................................................................................18
S7. SOLID AND LIQUID WASTE DISPOSAL....................................................................18
S8. DISCHARGES TO 303(d)ORTNIDL WATERBODIES................................................18
S9. STORMWATER POLLUTION PREVENTION PLAN...................................................21
S 10. NOTICE OF TERMINATION.......................................................................................:..29
GENER.AL CONDITIONS ...........................................................................................................30
G1. DISCHARGE VIOLATIONS ...........................................................................................30
G2. SIGNATORY REQUIREMENTS.....................................................................................30
G3. RIGHT OF INSPECTION AND ENTRY.........................................................................31
G4. GENERAL PERNIIT MODIFICATION AND REVOCATION......................................31
G5. REVOCATION OF COVERAGE UNDER THE PERMIT .............................................31
� G6. REPORTING A CAUSE FOR MODIFICATION............................................................32
G7. CONIPLIANCE WITH OTHER LAWS AND STATiJTES.............................................32
G8. DUT'Y TO REAPPLY.......................................................................................................32
G9. TRANSFER OF GENERAL PERMIT COVERAGE.......................................................32
G10. REMOVED SUBSTANCES.............................................................................................33
G11. DUTY TO PROVIDE INFORMATION...........................................................................33
G12. OTHER REQUIREMENTS OF 40 CFR...........................................................................33
G13. ADDITIONAL MONTTORING........................................................................................33
G14. PENALTIES FOR VIOLATING PERNIIT CONDITIONS .............................................33
G15. UPSET...............................................................................................................................34
G16. PROPERTY RIGHTS........................................................................................................34
G17. DUTY TO COMPLY........................................................................................................34
G18. TOXIC POLLUTANTS.....................................................................................................34
G 19. PENALTIES FOR TAMPERING.....................................................................................35
G20. REPORTING PLANNED CHANGES..............................................................................35
G21. REPORTING OTHER INFORMATION..........................................................................35
Page 3 of 46
G22. REPORTING ANTICIPATED NON-COMPLIANCE.....................................................35
G23. REQUESTS TO BE EXCLUDED FROM COVERAGE UNDER THE PERMIT..........36
G24. APPEALS..........................................................................................................................36
G25. SEVERABII.ITY...............................................................................................................36
G26. BYPASS PROHIBITED....................................................................................................36
APPENDIX A—DEFINITIONS...................................................................................................39
APPENDIX B—ACRONYMS .....................................................................................................46
SUI�IMARY OF PERNIIT REPORT SUBMITTALS
Refer to the Special and General Conditions for additional submittal requirements.
' Permit Submittal Frequency First Submittal Date
Section
SS.A High Turbidity/Transparency Phone As Necessary Within 24 hours
Reporting
, SS.B Discharge Monitoring Report Monthly Within 15 days after the
applicable monitoring
period
SS.F Noncompliance Notification As necessary Immediately
SS.F Noncompliance Notification—Written As necessary Within 5 Days of non-
Report compliance
G2. Notice of Change in Authorization As necessary
G6. Permit Applicarion for Substantive As necessary
Changes to the Discharge
G8. Application for Pernut Renewal 1/permit cycle No later than 180 days
before expuarion
G9. Notice of Permit Transfer As necessary
G20. Notice of Planned Changes As necessary
G22. Reporting Anticipated Non-compliance As necessary
SUMMARY OF REQUIRED ON SITE DOCUMENTATION
Permit Conditions Document Title '
Conditions S2, SS Permit Covera e Letter �,
Conditions S2, SS Construction Stormwater General Pernut
Conditions S4, SS Site Lo Book
Conditions S9, SS Storm���ater Pollution Prevention Plan SWPPP)
Page 4 of 46
SPECIAL CONDITIONS
Sl. PERMIT COVERAGE
A. Permit Area
This general pennit covers all areas of Washington State, except for federal and tribal
lands specified in S1.D3.
B. Operators Required to Seek Covera�e Under this General Pernut:
1. Operators of the following construction activities are required to seek coverage under
this permit:
a. Clearing, grading and/or excavation which results in the disturbance of one or
more acres, and discharges stormwater to surface waters of the state; and clearing,
grading and/or excavation on sites smaller than one acre which are part of a larger
common plan of development or sale, if the common plan of development or sale
will ultimately disturb one acre or more,and discharges stormwater to surface
waters of the state.
i. This includes forest practices that are part of a construcrion activity that will
result in the disturbance of one or more acres,and discharges to surface waters
of the state(i.e.,forest practices which are preparing a site for construction
activities); and
b. Any size construction activity discharging stormwater to waters of the state which
the Department of Ecology(Ecology):
i. Deternlines to be a significant contributor of pollutants to waters of the state of ,
Washington, or ,
ii. Reasonably expects to cause a violation of any water quality standard. I
2. Operators of the following activiries are not required to seek coverage under this
pemut, unless specifically required under Condition S 1.B.l.b. (Signif'icant
Contributor):
a. Constnzction activities which discharge all stormwater and non-stormwater to
ground water,and have no point source discharge to surface water or a storm
sewer system that drains to surface waters of the state;
b. Construction activities covered under an Erosivity Waiver(Condition S2.C);
c. Routine maintenance that is perforxned to maintain the original line and grade,
hydraulic capacity, or original purpose of a facility.
Page 5 of 46
C. Authorized Dischar�es:
1. Stormwater Associated with Construction Activitv. Subject to compliance with the
terms and conditions of this permit,Permittees are authorized to discharge
stormwater associated with construction activity to surface waters of the state or to a
storm sewer system that drains to surface waters of the state.
2. Stormwater Associated with Construction Support Activitv. This permit also
authorizes stormwater discharges from support activities related to the permitted
conshuction site(e.g., of�site equipment staging yards, material storage areas,
borrow areas, etc.)provided:
a. The support activity is directly related to the pernutted construction site that is
required to have an NPDES permit; and
b. The support activity is not a commercial operation serving multiple unrelated
construction projects, and does not operate beyond the completion of the
conshuction activity; and
c. Appropriate controls and measures are identified in the Stormwater Pollution
Prevention Plan(SWPPP)for the discharges from the support activity areas.
3. Non-Stormwater Discharges. The categories and sources of non-stormwater
discharges identified below are conditionally authorized, provided the discharge is
consistent with the terms and conditions of this pernut:
a. Discharges from fire fighting activities;
b. Fire hydrant system flushing;
c. Potable water including uncontaminated water line flushing(de-chlorinated);
d. Pipeline hydrostatic test water;
e. Uncontaminated air conditioning or compressor condensate;
f. Uncontaminated ground water or spring water;
g. Uncontaminated excavarion de-watering(in accordance with S9.D.10)
h. Uncontaminated discharges from foundation or footing drains;
i. Water used to control dust;
_ j. Routine external building wash down that does not use detergents; and
k. Landscape irrigation.
Page 6 of 46
All authorized non-stormwater discharges, except for discharges from fire fighting
, activities, shall be adequately addressed in the SWPPP and comply with Special
Condition S3.
D. Limitations on Covera�e
The Director may require any discharger to apply for and obtain coverage under an
individual pernut or another more specific general pemut. Such alternative coverage
will be required when Ecology determines that this general permit does not provide
adequate assurance that water quality will be protected; or there is a reasonable potential
� for the project to cause or contribute to a violation of water quality standards.
The following stormwater discharges are not covered by this pemut:
1. Post-construction stormwater discharges that originate from the site after construction
` activities have been completed and the site has undergone final stabilization.
2. Nonpoint source silvicultural activities such as nursery operations, site preparation,
reforestation and subsequent cultural treatment,thinning,prescribed burning,pest and
fue control,harvesting operations, surface drainage, or road construction and
maintenance from which there is natural runoff as excluded in 40 CFR Subpart
122.27.
3. Stormwater from any federal project or project on federal land or land within an
Indian Reservation except for the Puyallup Reservation. Within the Puyallup
Reservation, any project that discharges to surface water on land held in trust by the
federal government may be covered by this permit.
4. Stormwater from any site covered under an existing NPDES individual pernut in
which stormwater management and/or treatment requirements are included for all
stormwater discharges associated with construction activity.
5. Where an applicable Total Maximum Daily Load(TMDL) specifically precludes or
prohibits discharges from construction activity, the operator is not eligible for
coverage under this permit.
S2. APPLICATION REQUIREME�ITS
A. Permit A�plication Forms
1. Notice of Intent Form/Timeli.ne
a. Operators of new or previously unpermitted construction activities shall submit a
complete and accurate permit application form[Notice oflntent(NOI)] to
Ecology. Applicants are encouraged to use Ecology's internet-based electronic
NOI to apply for permit coverage.
b. The NOI shall be submitted on or before the date of the first public notice (see
Condition S2.B below) and at least 60 days prior to the discharge of stormwater
Page 7 of 46
from construction activiries. The 30-day public comment period required by WAC
173-226-130(5)begins on the publication date of the second public notice. Unless
Ecology responds to the complete application in writing,based on public
comments, or any other relevant factors,coverage under the general permit will
automatically commence on the thirty-first day following receipt by Ecology of a
completed NOI,or the issuance date of this permit,whichever is later;unless a
later date is specified by Ecology in writing.
c. Applicants that discharge to a storm sewer system operated by Seattle, King
� County, Snohomish County, Tacoma,Pierce County, or Clark County shall also
submit a copy of the NOI to the appropriate jurisdiction.
2. Transfer of Covera e�Form
Current coverage under this peimit may be transferred to one or more new operators,
including operators of sites within a Common Plan of Development,by submitting
a Transfer of Coverage Form in accordance with Condition G9. Transfers do not
require public notice.
B. Public Notice
For new or previously unpermitted sites,the applicant shall publish a public notice at
least one time each week for two consecutive weeks,with a 7-day time span between
dates, in a newspaper that has general circulation in the county in which the construction
is to take place.The notice shall contain the following:
1. A statement that"`The applicant is seeking coverage under the Washington State
Department of Ecology's Construction Stormwater NPDES and State Waste Discharge
General Permit";
2. The name, address and location of the constxuction site;
3. The name and address of the applicant;
4. The type of construction activity that will result in a discharge, (e.g.,residential
construction,commercial construction, etc.) and the number of acres to be disturbed;
5. The name of the receiving water(s) (i.e.,the surface water(s)that the site will discharge
to),or if the discharge is through a storm sewer system,the name of the operator of the
storm sewer, and
6. The statement: "Any person desiring to present their views to the Department of
Ecology regarding this application,or interested in the DepartmenYs action on this
application may notify the Department of Ecology in writing within 30 days of the last
date of publication of this notice. Comments can be submitted to: Department of
Ecology,P.O. Box 47696,Olympia,WA 985047696, Attn: Water Quality Program,
Construction Stormwate�".
Page 8 of 46
C. Erosivitv Waiver
Operators may qualify for a waiver from the permit if the following conditions are met:
1. The site will result in the disturbance of less than 5 acres; and the site is not a portion
of a common plan of development or sale that will disturb 5 acres or greater.
2. Calculation of Erosivity"R"Factor and Regional Timeframe:
a. The projecYs rainfall erosivity factor("R" Factor)must be less than 5 during the
period of construction activity, as calculated using the Texas A&M University '
online rainfall erosivity calculator at:http:Uei.tamu.edu/. The period of
construction activity begins at initial earth disturbance and ends with final
stabilization; and,in addition:
b. The entire period of construction activity must fall within the following
timeframes:
i. For sites west of the Cascades Crest: June 15—September 15; or
ii. For sites east of the Cascades Crest, excluding the Central Basin: June 15—
October 15; or
iii. For sites east of the Cascades Crest,within the Central Basin*: no additional
timeframe restrictions apply.
*I�Tote: The Central Basin is defined as the portions of Eastem Washington
with mean annual precipitation of less than 12 inches.
3. Operators must submit a complete Erosivity Waiver Certification Form at least one
«�eek prior to commencing land disturbing activities. Certification must include:
a. A statement that the operator will comply with applicable local stormwater
requirements; and
b. A statement that the operator will implement appropriate erosion and sediment
control BMPs to prevent violations of water quality standards.
4. This waiver is not available for facilities declared a significant contributor of �I
pollutants as defined in Condition S1.B.l.b.
5. This waiver does not apply to construction activity which includes non-stormwater
discharges listed in S 1.C.3.
6. If construction activity extends beyond the certified waiver period for any reason, the
operator shall either:
Page 9 of 46
a. Recalculate the rainfall erosivity"R" factor using the original start date and a new
projected ending date and,if the"R"factor is still under 5 and the entire project
falls within the applicable regional timeframe in S2.C.2.b,complete and submit
an amended waiver certificarion form before the original waiver expires; or
b. Submit a complete pemut application to Ecology in accordance with Condition
S2.A and B before the end of the certified waiver period.
S3. COMPLIANCE WITH STANDARDS
A. Discharges shall not cause or contribute to a violarion of surface water quality standards
(Chapter 173-201A WAC), ground water quality standards(Chapter 173-200 WAC),
sediment management standards(Chapter 173-204 WAC), and human health-based
criteria in the National Toxics Rule(40 CFR Part 131.36). Discharges that are not in
compliance with these standards are not authorized.
B. Prior to the discharge of stormwater and non-stormwater to waters of the state, the
Permittee shall apply all knovvn,available, and reasonable methods of prevention,
control,and treatment(AKAR7�. This includes the preparation and implementation of an
adequate Stormwater Pollution Prevention Plan(SWPPP),with all appropriate best
nzanagement practices(BMPs)installed and maintained in accordance with the SWPPP
and the terms and conditions of this permit.
C. Compliance with water quality standards shall be presumed,unless discharge monitoring
data or other site specific information demonstrates that a dischazge causes or contributes
to a violation of water quality standards,when the Permittee is:
1. In full compliance with all pemut conditions, including planni.ng, sampling,
monitori.ng,reporting, and recordkeeping conditions; and
2. Fully implementing stormwater BMPs contained in stormwater management manuals
published or approved by Ecology,or BMPs that are demonstrably equivalent to
BMPs contained in stormwater technical manuals published or approved by Ecology,
including the proper selection,implementation, and maintenance of all applicable and
appropriate BMPs for on-site pollution control.
D. For sites that discharge to both surface water and ground water,all ground water
discharges aze also subject to the terms and conditions of this permit. Permittees who
discharge to ground water through an injection well shall comply with any applicable
requirements of the Underground Injecrion Control(LTIC)regulations, Chapter 173-218
WAC.
Page 10 of 46
S4. MOIVITORING REQUIItEMENTS
The primary monitoring requirements are summarized in Table 3 (below):
Table 3. Summary of Monitoring Requirementsl
Size of Soil Disturbance Weekly Weekly Weekly �'Veekly
Site Sampling w/ Sampling w/ pH
Inspections Turbidity Meter Transparency sampling3
Tube
Sites which disturb less than 1 Required Not Required Not Required Not
acre Re uired
Sites which disturb 1 acre or Required Sampling Requir4d—either Required
more, but less than 5 acres method
Sites which disturb 5 acres or Required Required Not Required5 Required
more
A. Site Lo B�ook
The Permittee shall maintain a site log book that contains a record of the
- implementation of the SWPPP and other pemut requirements including the installation
and maintenance of BMPs, site inspections, and stormwater monitoring.
B. Site Inspections
1. Site inspections shall include all areas disturbed by construction activities, all BMPs,
and all stormwater discharge points. Stormwater shall be visually examined for the
1 Additional monitoring requuements may apply for: 1)discharges to 303(d)listed waterbodies and waterbodies
with applicable TMDLs for turbidity,fine sediment,high pH,or phosphorus-see Condition S8;and 2)sites
requued to perform additional monitoring by Ecology order—see Condition G13.
2 Soil disturbance is calculated by adding together all areas affected by construction activity.Construction Activity
means clearing,grading,excavation,and any other activity which disturbs the surface of the land,including
ingress/egress from the site.
3 Beginning October 1,2006,if construction activity involves significant concrete work or the use of�gineered
soils,and stormwater from the affected area drains to a stormwater collection system or other surface water,the
Permittee shall conduct pH sampling in accordance with Condirion S4.D.
4 Begirming October 1,2008,sites with'one or more acres,but less than 5 acres of soil disturbance,shall conduct
turbidity or transparency sampling in accordance with Condition S4.C.
5 Beginning October I,2006,sites greater than or equal to 5 acres of soil disturbance shall conduct turbidity
sampling using a turbidity meter in accordance with Condition S4.C.
Page 11 of 46
presence of suspended sediment,turbidity, discoloration, and oil sheen. Inspectors
shall evaluate the effectiveness of BMPs and determine if it is necessary to install,
maintain, or repair BMPs to improve the quality of stormwater discharges.
Based on the results of the inspection,the Pemuttee shall correct the problems
identified as follows:
a. Review the SWPPP for compliance with Condition S9 and make appropriate
revisions within 7 days of the inspection; and
b. Fully implement and maintain appropriate source control and/or treatment BMPs
as soon as possible,but no later than 10 days of the inspection; and
c. Document BMP implementation and maintenance in the site log book.
2. The site inspections shall be conducted at least once every calendar week and within
24 hours of any discharge from the site.The inspection frequency for temporarily
stabilized, inactive sites may be reduced to once every calendar month.
3. Site inspections shall be conducted by a person who is laiowledgeable in the
principles and practices of erosion and sediment control. The inspector shall have the
skills to:
a. Assess the site conditions and construction activities that could impact the quality
of stormwater, and
b. Assess the effectiveness of erosion and sediment control measures used to control
the quality of stormwater discharges.
4. Beginniug October 1, 2006, construction sites one acre or larger that discharge
stormwater to surface waters of the state, shall have site inspections conducted by a
Certified Erosion and Sediment Control Lead(CESCL). The CESCL shall be
identified in the SWPPP and shall be present on-site or on-call at all times.
Certification shall be obtained through an approved erosion and sediment control
training program that meets the minimum training standards established by Ecology
(see BMP C160 in the Manual).
5. The inspector shal�summarize the results of each inspection in an inspection report or
checklist and be entered into, or attached to,the site log book.At a min;mum, each
inspection report or checklist shall include:
a. Inspection date and time.
b. Weather information; general conditions during inspecrion and approximate
amount of precipitation since the last inspection, and within the last 24 hours.
c. A summary or list of all BMPs which have been implemented, including
observations of all erosion/sediment control structures or practices.
d. The following shall be noted:
i. locations of BMPs i.nspected,
- -
1
j a �
Pabe 1_ of 46
� ii. locarions of BMPs that need maintenance,
iii. the reason maintenance is needed,
� iv. locations of BNIPs that failed to operate as designed or intended, and
v. locations where additional or different BMPs are needed, and the reason(s) why.
ie. A descriprion of stormwater discharged from the site. The inspector shall note the
presence of suspended sediment, turbid water, discoloration, andlor oil sheen, as
� applicable.
f. Any water quality monitoring performed during inspection.
� g. General comments and notes, including a brief description of any BMP repairs,
maintenance or installations made as a result of the inspection.
h. A statement that, in the judgment of the person conducting the site inspection,the
� site is either in compliance or out of compliance with the terms and conditions of
the SWPPP and the permit. If the site inspection indicates that the site is out of
compliance, the inspection report shall include a summary of the remedial actions
j required to bring the site back into compliance, as well as a schedule of
implementation.
� i. Name,title, and signature of the person conducting site inspection; and the
following statement: "I certify that this report is true, accurate, and complete,to
the best of my knowledge and belief'.
tC. Turbidity/Transparencv Samplin�quirements
i
1. Sampling Methods/Effective Dates
Ia. Beginning October 1,2006, if construction activity will involve the disturbance
of 5 acres or more, the Permittee shall conduct turbidity sampling per Condition
S4.C.
; � b. Beginniug October 1,2008, if construction activity will involve greater than or
equal to 1 acre,but less than 5 acres of soil disturbance, the Permittee shall
I � conduct transparency sampling or turbidity sampling per Condition S4.C.
2. Sampling Frequency
� � a. Sampling shall be conducted at least once every calendar week, when there is a
discharge of stormwater(or authorized non-stormwater) from the site. Samples
shall be representative of the flow and characteristics of the discharge.
iI b. When there is no discharge during a calendar week, sampling is not required.
c. Sampling is not required outside of normal working hours or during unsafe
I � conditions. If a Permittee is unable to sample during a monitoring period,the
Discharge Monitoring Report(DMR) shall include a brief explanation.
1�
!l
Page 14 of 46
If discharge turbidity is greater than or equal to 250 NTU; or if discharge
transparency is less than or equal to 6 cm,the CESCL shall:
i. Notify Ecology by phorie in accordance with Condition SS.A.; and
u. Review the SWPPP for compliance with Condition S9 and make appropriate
, revisions within 7 days of the discharge that exceeded the benchmark; and
iii. Fully implement and maintain appropriate source control and/or treatment
BMPs as soon as possible,but within 10 days of the discharge that
exceeded the benchmark;
iv. Document BMP implementation and maintenance in the site log book; and
� v. Continue to sample discharges daily until:
� l. turbidity is 25 NTU(or lower); or
2. transparency is 31 cm(or greater); or
3. the CESCL has demonstrated compliance with the water quality
standard for turbidity:
a. no more than 5 NTU over background turbidity, if background is
less than 50 NTU, or
b. no more than 10%over background turbidity, if background is 50
NTU or greater; or
4. the discharge stops or is eliminated.
D. pH Monitorin�: Sites with Sienificant Concrete Work or Engineered Soils
Beginning October 1,2006,if construction activity will result in the disturbance of 1
acre or more, and involves significant concrete work or the use of engineered soils, and
stormwater from the affected area drains to surface waters of the state or to a storm
sewer system that drains to surface waters of the state, the Permittee shall conduct pH
monitoring as set forth below:
1. For sites with significant concrete work, the pH nzonitoring period shall commence
when the concrete is first exposed to precipitation and continue«-eekly until
stormwater pH is 8.5 or less.
a. "Significant concrete work"means greater than 1000 cubic yards poured concrete
or recycled concrete.
2. For sites with engineered soils,the pH monitoring period shall commence when the
soil amendments are first exposed to precipitation and shall continue until the azea of
engineered soils is fully stabilized.
Page 15 of 46
a. "Engineered soils"means soil amendments including,but not 1'united,to Portland
cement treated base(CTB), cement kiln dust(CKD), or fly ash.
3. During the pH monitoring period, the Permittee shall obtain a representative sample
_ of stormwater and conduct pH analysis at least once per week.
4. The Permittee shall monitor pH in the sediment trap/pond(s) or other locations that
receive stormwater runoff from the area of significant concrete work or engineered
' soils prior to discharge to surface waters.
' S. The benchmark value for pH is 8.5 standard units. Any time sampling indicates that
pH is 8.5 or greater,the Pemuttee shall:
a. Prevent the high pH water(8.5 or above) from entering storm sewer systems or
surface waters; and
b. If necessary, adjust or neutralize the high pH water using an appropriate treatment
BMP such as CO2 sparging or dry ice. The Permittee shall obtain written
approval from Ecology prior to using any form of chemical treatment other than
COZ sparging or dry ice.
6. The Permittee shall perform pH analysis on-site with a calibrated pH meter,pH test
kit, or wide range pH indicator paper. The Permittee shall record pH monitoring
results in the site log book.
S5. REPORTING AND RECORDKEEPING REQUIItEMENTS
A. High Turbidity Phone Reporting
Any time sampling performed in accordance with Special Condition S4.0 indicates
turbidity is 2�0 NTU or greater(or transparency is 6 cm or less)the Pernuttee shall notify
the appropriate Ecology regional office by phone within 24 hours of analysis.
B. Discharpe Monitorin�Reports
1. Permittees required to conduct water quality sampling in accordance with Special
Conditions S.4.0(Turbidity/Transparency), S4.D(pH) and/or S8 [303(d)/TMDL
sampling] shall submit the results to Ecology monthly on Discharge Monitoring
Report(DMR) forms provided by Ecology.
Permittees are authorized and encouraged to submit electronic DMRs using the"E-
DMR FoYm"on Ecology's Construction Stormwater web site:
htt�://www.ecv.wa.�ov/pro grams/wq/stormwater'constructian./.
2. The Permittee shall submit DMR forms electronically or by mail to be received by
Ecology withi.n 15 days following the end of each month. If there was no discharge
during a given monitoring period, the Permittee shall submit the form as required
with the words "no discharge" entered in place of the monitoring results. If the
Permittee is unable to submit discharge monitori.ng reports electronically, the
Permittee may mail reports to the address listed below:
Page 16 of 46
Department of Ecology
Water Quality Program-Construction Stormwater
PO Box 47696
Olympia,Washington 98504-7696
C. Records Retention
The Pennittee shall retain records of all monitoring information(site log book, sampling
results, inspection reports/checklists, etc.), Stormwater Pollution Prevention Plan, and
any other documentation of compliance with permit requirements duri.ng the life of the
construction project and for a minimum of three years following the termivation of
pemut coverage. Such information shall include all calibration and maintenance records,
and records of all data used to complete the application for this pemut. This period of
retention shall be extended during the course of any unresolved litigation regarding the
discharge of pollutants by the Permittee or when requested by Ecology.
D. Recordin�of Results
For each measurement or sample taken, the Permittee shall record the following
information:
1. Date,place,method, and time of sampling or measurement;
2. The individual who performed the sampling or measurement;
3. The dates the analyses were performed;
4. The individual who performed the analyses;
5. The analytical techniques or methods used; and
6. The results of all analyses.
E. Additional Monitoring by the Pemuttee
If the Permittee monitors any pollutant more frequently than required by this pemut using
test procedures specified by Condition S4 of this permit, the results of this monitoring
shall be included in the calculation and reporting of the data submitted in the Permittee's
� DMR. � � �
F. Noncompliance Notification
In the event the Permittee is unable to comply with any of the terms and conditions of
this permit which may cause a threat to human health or the environment, the Permittee
shall:
1. Immediately notify Ecology of the failure to comply.
2. Ixnmediately take action to prevent the discharge/pollution, or otherwise stop or
correct the noncompliance,and, if applicable,repeat sampling and analysis of any
noncompliance immediately and submit the results to Ecology within five(5) days ,
after becoming aware of the violation. I
Page 17 of 46
3. Submit a detailed written report to Ecology within five(5) days,unless requested
earlier by Ecology.The report shall contain a description of the noncompliance,
including exact dates and times, and if the noncompliance has not bee�corrected, the
anticipated time it is expected to continue; and the steps taken or planned to reduce,
eliminate,and prevent reoccurrence of the noncompliance.
Compliance with these requirements does not relieve the Permittee from
responsibility to maintain continuous compliance with the terms and conditions of
this permit or the resulting liability for failure to comply.
G. Access to Plans and Records
1. The Permittee shall retain the following permit documentation(plans and records) on-
site, or within reasonable access to the site, for use by the operator; or on-site review
by Ecology or the local jurisdiction:
a. General Pemut;
b. Permit Coverage Letter;
c. Stormwater Pollution Prevention Plan(SWPPP); and
d. Site Log Book
2. The Permittee(s) shall address written requests for plans and records listed above
(Condition SS.G.1)as follows:
a. A copy of plans and records shall be provided to Ecology within 14 days of
receipt of a written request from Ecology.
b. A copy of plans and records sha11 be provided to the public when requested in
writing. Upon receiving a written request from the public for the Permittee's
plans and records,the Permittee shall either:
i. Provide a copy of the plans and records to the requestor within 14 days of a
receipt of the written request; or
ii. Notify the requestor within 10 days of receipt of the written request of the
location and times within normal business hours when the plans and records
may be viewed, and provide access to the plans and records within 14 days of
receipt of the written request; or
ui. Within 14 days of receipt of the written request,the Pemuttee may submit a
copy of the plans and records to Ecology for viewing and/or copying by the
requestor at an Ecology office, or a mutually agreed upon location. If plans
and records are viewed and/or copied at a location other than at an Ecology
office,the Permittee will provide reasonable access to copying services for
which a reasonable fee may be charged. The Permittee shall notify the
Page 18 of 46 II
requestor within 10 days of receipt of the request where the plans and records
may be viewed and/or copied.
S6. PERMIT FEES
The Permittee shall pay permit fees assessed by Ecology. Fees for stormwater discharges
covered under this permit shall be established by Chapter 173-224 WAC. Permit fees will
continue to be assessed until the permit is terminated in accordance with Special Condition
S 10 or revoked in accordance with General Condition G5.
S7. SOLID AND LIQUID WASTE DISPOSAL
Solid and liquid wastes generated by construction activity such as demolition debris,
construction materials,contauunated materials,and waste materials from maintenance
activities, including liquids and solids from cleaning catch basins and other stormwater
facilities, shall be handled and disposed of in accordance with:
1. Special Condirion S3, Compliance with Standards, and
2. WAC 173-216-110,and other applicable regulations. '
S8. DISCHARGES TO 303(D) OR TNIDL WATERBODIES
A. Samplin� and Numeric Effluent Limitations For Discharges to 303(dl-listed Waterbodies
1. 1.Permittees that discharge to water bodies listed as impaired by the State of
Washington under Section 303(d) of the Clean WaterAct for turbidity,fine
sediment,high pH,or phosphorus, shall conduct water quality sampling according
to the requirements of this section.
2. All references and requirements associated with Section 303(d)of the Clean Water
Act mean the most current listing by Ecology of impaired waters that exists on
November 16, 2005,or the date when the operator's complete permit application is
received by Ecology,whichever is later.
B. Dischar�es to 303(d)-Listed Waterbodies(Turbiditv,Fine Sediment,or Phosphorus�
1. Permittees which discharge to waterbodies on the 303(d) list for turbidity, fine
sediment, or phosphorus shall conduct turbidity sampling at the following locations
to evaluate compliance with the water quality standard for turbidity:
a. Background turbidity shall be measured i.n the 303(d)-listed receiving water
unmediately upstream(upgradient)or outside the area of influence of the
discharge; and
b. Discharge turbidity shall be measured at the point of discharge into the 303(d)
listed receiving waterbody, inside the area of influence of the discharge; or
Page 19 of 46
Altematively,discharge turbidity may be measured at the point where tlie
discharge leaves the construction site,rather than in the receiving waterbody.
2. Based on sampling,if the discharge turbidity exceeds the water quality standard for
turbidity(more than 5 NTU over background turbidity when the background
turbidity is 50 NTU or less, or more than a 10%increase in turbidity when the
background turbidity is more than 50 NTiJ), all future discharges shall comply with
a numeric eftluent limit which is equal to the water quality standard for turbidity.
3. If a future discharge exceeds the water quality standard for turbidity,the Permittee
shall:
a. Review the SWPPP for compliance with Condition S9 and make appropriate
revisions within 7 days of the discharge that exceeded the standard;
� b. Fully implement and maintain appropriate source control and/or treatment BMPs
as soon as possible,but within 10 days of the discharge that exceeded the
standard;
c. Document BMP implementation and maintenance in the site log book;
d. Notify the appropriate Ecology Regional Office by phone within 24 hours of
analysis;
e. Continue to sample daily until discharge turbidity meets the water quality
standard for turbidity.
C. Dischar�es to waterbodies on the 303(d)list for High pH
1. Pernlittees which discharge to waterbodies on the 303(d) list for high pH shall
conduct sampling at one of the following locations to evaluate compliance with the
water quality standard for pH(in the range of 6.5—8.5):
a. pH shall be measured at the point of discharge into the 303(d) listed waterbody,
inside the area of influence of the discharge; or
b. Altematively,pH may be measured at the point where the discharge leaves the
construction site,rather than in the receiving water.
2. Based on the sampling set forth above, if the pH exceeds the water quality standard
for pH(in the range of 6.5— 8.5), all future discharges shall comply with a numeric
effluent limit which is equal to the water quality standard for pH.
3. If a future discharge exceeds the water quality standard for pH,the Permittee shall:
a. Review the SWPPP for compliance with Condition S9 and make appropriate
revisions withi.n 7 days of the discharge that exceeded the water quality standard;
Page 20 of 46
b. Fully implement and maintain appropriate source control and/or treatment BMPs
as soon as possible,but within 10 days of the discharge that exceeded the
standards;
c. Document BMP implementation and maintenance in the site log book;
d. Notify the appropriate Ecology Regional Office by phone within 24 hours of
analysis; and
e. Continue to sample daily until discharge meets the water quality standard for pH I
(in the range of 6.5—8.5) or the discharge stops or is elurunated. II
Parameter identified Parameter/LJnits Analytical Sampling Water Quality I��
in 303(d) listing Method Frequency Standard
Turbidity Turbidity/NTU SM2130 or Weekly, if If background is 50 I
Fine Sediment EPA180.1 discharging NTU or less: 5 NTU
Phosphorus over background; or
If background is
more than 50 NTU:
10% over
background
High pH pH/Standard pH meter Weekly, if In the range of
Units discharging 6.5—8.5
D. Sampling and L'unitations For Sites Dischar��pplicable TNIDLs
1. Discharges to a waterbodies subject to an applicable Total Maximum Daily Load
(TMDL) for turbidity, fine sediment, high pH, or phosphorus, shall be consistent with
the assumptions and requirements of the TMDL.
a. Where an applicable TMDL sets specific waste load allocations or requirements
for discharges covered by this permit, discharges shall be consistent with any
specific waste load allocations or requirements established by the applicable
TMDL.
u.The Permittee sha11 sample discharges weekly,or as otherwise specified by the
TNIDL,to evaluate compliance with the specific waste load allocations or
requirements.
iu.Analytical methods used to meet the monitoring requirements shall conform to
the latest revision of the Guidelines Establishing Test Procedures for the
Analysis of Pollutants contained in 40 CFR Part 136. Turbidity and pH methods
Page 21 of 46
need not be accredited or registered unless conducted at a laboratory which must
otherwise be accredited or registered.
b. Where an applicable TMDL has established a general waste load allocation for
construction stormwater discharges,but no specific requirements have been
identified, compliance with Conditions S4 (Monitoring) and S9 (SWPPPs)will be
assumed to be consistent with the approved TNIDL.
c. Where an applicable TMDL has not specified a waste load allocation for
construction stormwater discharges, but has not excluded these discharges,
compliance with Conditions S4 (Monitoring) and S9 (SWPPPs)will be assumed
to be consistent with the approved TNIDL.
d. Where an applicable TNIDL specifically precludes or prohibits discharges from
constxuction activity, the operator is not eligible for coverage under this pernut.
2. Applicable TMDL means a TMDL for turbidity, fine sediment,high pH,or
phosphorus,which has been completed and approved by EPA prior to November 16,
2005, or prior to the date the operator's complete permit application is received by
Ecology,whichever is later. TMDLs completed after the operator's complete permit
application is received by Ecology become applicable to the Permittee only if they are
imposed through an administrative order by Ecology, or through a modification of
permit coverage.
S9. STORM�VATER POLLUTION PREVENTION PLAN
An adequate Stormwater Pollution Prevention Plan(SWPPP) for conshuction activity shall
be prepared and implemented in accordance with the requirements of tlus permit beginni.ng
with initial soil disturbance and until final stabilization.
A. The SWPPP shall meet the following objectives:
1. To implement Best Management Pracrices(BMPs)to prevent erosion and
sedimentation,and to identify,reduce, eliminate or prevent stormwater contamination
and water pollution from construction activity.
2. To prevent violations of surface water quality,ground water quality, or sediment
management standards. .
3. To control peak volumetric flow rates and velocities of stormwater discharges.
B. General Requirements
1. The SWPPP shall include a narrative and drawings. All BMPs shall be clearly
referenced in the narrative and marked on the drawings.
The SWPPP narrative shall include documentation to explain and justify the pollution
prevention decisions made for the project. Documentation shall include:
a. Information about e�sting site conditions (topography, drainage, soils,
vegetation, etc.);
Page 22 of 46
b. Potential erosion problem areas;
Ic. The 12 elements of a SWPPP in S9.D.1-12, including BMPs used to address each
i ;
element;
d. Construction phasing/sequence and general BMP implementation schedule;
e. The actions to be taken if BMP perforxnance goals are not achieved; and
f. Engineering calculations for ponds and any other designed structures.
2. The Permittee shall modify the SWPPP if, during inspections or investigations
conducted by the owner/operator, or the applicable local or state regulatory authority,
it is determined that the SWPPP is, or would be, ineffective in eliminating or
significantly minunizing pollutants in stormwater discharaes from the site. The
Pernuttee shall take the following actions:
a. Review the SWPPP for compliance with Condition S9 and make appropriate
revisions within 7 days of the inspection or investigation;
b. Fully implement and maintain appropriate source control and/or treatment BMPs
as soon as possible,but no later than 10 days from the inspection or investigation;
and
c. Document BMP implementation and maintenance in the site log book.
3. The Pernuttee shall modify the SWPPP whenever there is a change in design,
construction, operation,or maintenance at the construction site that has, or could
have,a significant effect on the discharge of pollutants to waters of the state.
C. Stormwater Best Mana�ement Practices (BMPs�
BMPs shall be consistent with:
1. Stormwater Management Manual for Western Washington(most recent edition), for
sites west of the crest of the Cascade Mountains;
2. Stormwater Management Manual for Eastern Washington(most recent edition), for
sites east of the crest of the Cascade Mountains; or
3. Other stormwater management guidance documents or manuals which provide an
equivalent level of pollution prevention and are approved by Ecology; or
4. Documentarion in the SWPPP that the BMPs selected provides an equivalent level of
pollution prevention, compared to the applicable Stormwater Management Manuals,
including:
Page 23 of 46
' a. The technical basis for the selection of all stormwater BMPs(scientific, technical
studies, and/or modeling) which support the performance claims for the BMPs
being selected; and
b. An assessment of how the selected BMP will satisfy AKART requirements and
the applicable federal technology-based treatment requirements under 40 CFR
part 125.3.
_ D. SWPPP—Narrative Contents and Requirements
The Permittee shall include each of the 12 elements below in S9.D.1-12 in the narrative
of the SWPPP and ensure that they are implemented unless site conditions render the
element unnecessary and the exemprion from that element is clearly justified in the
SWPPP.
1. Preserve Vegetation/Mark Clearing Limits
a. Prior to beginning land disturbing activiries, including clearing and grading,
clearly mark all clearing limits,sensitive areas and their buffers, and trees that are
to be preserved within the construction area.
b. The duff layer,native top soil, and na.tural vegetation shall be retained in an
undisturbed state to the maximum degree practicable.
2. Establish Construction Access
a. Construction vehicle access and exit shall be limited to one route,if possible.
b. Access points shall be stabilized with a pad of quarry spalls, crushed rock,or other
equivalent BMP,to m;n;mi�e the tracking of sediment onto public roads.
c. Wheel wash or tire baths shall be located on site,if the stabilized construction
entrance is not effective in preventing sediment from being tracked onto public
roads.
d. If sediment is tracked off site,public roads shall be cleaned thoroughly at the end of
each day,or more frequently during wet weather. Sediment shall be removed from
roads by shoveling or pickup sweeping and shall be traxisported to a controlled
sediment disposal area.
e. Street washing is allowed only after sediment is removed in accordance with
S9.D.2.d. Street wash wastewater shall be controlled by pumping back on site or
otherwise be prevented from discharging into systems tributary to waters of the
state.
3. Control Flow Rates
a. Properties and waterways downstream from development sites sha.11 be protected
from erosion due to increases in the velocity and peak volumetric flow rate of
stormwater runoff from the project site,as required by local plan approval
authority.
Page 24 of 46
, b. `Vhere necessary to comply with S9.D.3.a., stormwater retention or detentio�t
facilities shall be constructed as one of the first steps in grading. Detention
facilities shall be functional prior to construction of site improvements(e.g.,
impervious surfaces).
c. If permanent infiltration ponds are used for flow control during construction,these
facilities shall be protected from siltation during the construction phase.
4. Install Sediment Controls
a. Stormwater runoff from disturbed areas shall pass through a sediment pond or other
appropriate sediment removal BMP,prior to leaving a construcrion site or prior to
discharge to an infiltration facility. Runoff from fully stabilized areas may be
discharged without a sediment removal BMP,but sha.11 meet the flow control
performance standard of S9.D.3.a.
b. Sediment control BNIPs (sediment ponds, traps, filters,etc.)shall be constructed as
� one of the first steps in grading. These BMPs shall be functional before other land
disturbing activities take place.
c. BMPs intended to trap sediment on site shall be located in a manner to avoid
interference with the movement of juvenile salmonids attempting to enter off-
channel areas or drainages.
5. Stabilize Soils
a. Exposed and unworked soils shall be stabilized by application of effective BMPs
that prevent erosion. Applicable BMPs include,but are not limited to: temporary
and permanent seeding, sodding, mulching,plastic covering, emsion control fabrics
and matting, soil application of polyacrylanude(PA1Vn, the early application of
gravel base on areas to be paved, and dust control.
b. Depending on the geographic location of the project,no soils shall remain exposed
and unworked for more than the time periods set forth below to prevent erosion:
West of the Cascade Mountains Crest
During the dry season(May 1 - Sept. 30): 7 days
During the wet season(October 1 -Apri130): 2 days
East of the Cascade Mountains Crest, except for Central Basin*
During the dry season(July 1 - September 30): 10 days
During the wet season(October 1 -June 30): 5 days
The Central Basin*, East of the Cascade Mountains Crest
During the dry Season(July 1 - September 30): 30 days
During the wet season(October 1 -June 30): 15 days
*Note: The Central Basin is defined as the portions of Eastern Washington
with mean annual precipitation of less than 12 inches.
�
Page 26 of 46
b. Inlet protection devices shall be cleaned or removed and replaced when sediment
has filled one-third of the available storage(unless a different standard is specified
by the product manufacturer).
8. Stabilize Channels and Oudets
_ a. All temporary on-site conveyance channels shall be designed,constructed, and
stabilized to prevent erosion from the following expected peak flows:
i. West of the Cascade Mountains Crest: Channels shall handle the peak 10
minute velocity of flow from a Type lA, 10-year, 24-hour frequency storm for
the developed condition. Alternatively,the 10-year, 1-hour flow rate indicated
by an approved continuous runoff model,increased by a factor of 1.6,may be
- used. The hydrologic analysis shall use the existing land cover condition for
predicting flow rates from tributary areas outside the project limits.For
tributary areas on the project site, the analysis shall use the temporary or
permanent project land cover condition,whichever will produce the highest
' flow rates. If using the WWHM to predict flo�us,bare soil areas should be
modeled as "landscaped area."
, "- ii. East of the Cascade Mountains Crest: Channels shall handle the expected peak
flow velocity from a 6-month, 3-hour storm for the developed condition,
referred to as ihe short duration storm.
b. Stabilization,including armoring material, adequate to prevent erosion of outlets,
adjacent stream banks,slopes, and downstream reaches shall be provided at the
outlets of all conveyance systems.
9. Control Pollutants
a. All pollutants,including waste materials and demolition debris,that occur onsite
shall be handled and disposed of in a inanner that does not cause contaminarion of
stormwater.
b. Cover, containment, and protection from vandalism shall be provided for all
chemicals, liquid products,petroleum products,and other materials that have the
potential to pose a threat to human health ar the environment.On-site fueling tanks
shall include secondary containment.
c. Maintenance,fueling,and repair of hea�y equipment and vehieles shall be
conducted using spill prevention and control measures. Contaminated surfaces shall
be cleaned immediately following any spill incident.
d. Wheel wash or tire bath wastewater shall be discharged to a separate on-site
treatment system or to the sanitary sewer with local sewer dishict approval.
e. Application of fertilizers and pesticides, shall be conducted in a manner and at
applica.tion rates that will not result in loss of chemical to stormwater runoff.
Manufacturers' label requirements for application rates and procedures shall be
follo«zed.
� I
Page 27 of 46
f. BMPs shall be used to prevent or treat contamination of stormwater runoff by pH
modifying sources. These sources include,but are not limited to:bulk cement,
cement kiln dust,fly ash,new concrete washing and curing waters,waste streams
generated from concrete grinding and sawing,exposed aggregate processes,
dewatering concrete vaults,concrete pumping and mi�cer washout waters.
Permittees shall adjust the pH of stormwater if necessary to prevent violations of
water quality standards.
g. Pernuttees shall obtain written approval from Ecology prior to using chemical
treatment,other than CO2 or dry ice to adjust pH.
10. Control De-Watering
a. Foundation,vault, and trench de-watering water,which have si.milar characteristics
to stormwater runoff at the site, shall be discharged into a controlled conveyance
system prior to discharge to a sediment�ap or sediment pond.
b. Clean,non-turbid de-watering water, such as well-point ground water,can be
discharged to systems tributary to,or directly into surface waters of the state,as
specified in S9.D.8,provided the de-watering flow does not cause erosion or
flooding of receiving waters. Clean de-wateri.ng water should not be routed through
storxnwater sediment ponds.
c. Other de-watering disposal options may include:
i. infiltration
ii. transport offsite in a vehicle, such as a vacuum flush truck, for legal disposal in
a manner that does not pollute state waters,
iii. Ecology-approved on-site chemical treatment or other suitable treatment
technologies,
iv. sanitary sewer discharge with local sewer district approval, if there is no other
option,or
v. use of a sedimentation bag with outfall to a ditch or swale for small volumes of
localized de-wateri.ng.
d. Highly turbid or contaminated dewatering water shall be handled separately from ,
stormwater.
11.Maintain BMPs
a. All temporary and permanent erosion and sediment control BMPs shall be '
maintained and repaired as needed to assure continued performance of their
intended function in accordance with BMP specifications.
b. All temporary erosion and sediment control BMPs shall be removed withi.n 30 days
after final site stabilization is achieved or after the temporary BMPs are no longer
needed.
Page 28 of 46
12. Manage the Project
a. Development projects shall be phased to the maximum degree practicable and shall
take into account seasonal work limitations.
b. Inspection and Monitoring
All BMPs shall be inspected,maintained, and repaired as needed to assure
conti.nued performance of their intended function. Site inspections and monitoring
shall be conducted in accordance with S4.
c. Maintaining an Updated Construction SWPPP
The SWPPP shall be maintained,updated, and implemented in accordance with
Conditions S3, S4 and S9.
E. SWPPP—Map Contents and Requirements
The SWPPP shall also include a vicinity map or general location map (e.g.USGS
Quadrangle map, a portion of a county or city map, or other appropriate map) with
enough detail to identify the location of the construction site and receiving waters within
one mile of the site.
The SWPPP shall also include a legible site map(or maps) showing the entire
construction site. The following features shall be identified,unless not applicable due to
site conditions:
1. The direction of north,property lines, and existi.ng structures and roads;
2. Cut and fill slopes indicating the top and bottom of slope catch lines;
3. Approximate slopes, contours, and direction of stormwater flow before and after
major grading activities;
4. Areas of soil disturbance and azeas that will not be disturbed;
5. Locations of structural and nonstructural controls(BMPs}identified in the SWPPP
6. Locations of off-site material, stockpiles,waste storage,borrow areas,and
vehicle/equipment storage areas;
7. Locations of all surface water bodies, includi.ng wetlands;
8. Locations where stormwater or non-stormwater dischazges off-site and/or to a surface
water body,including wetlands;
9. Location of water quality sampling station(s),if sampling is required by state or local
permitking authority; and
Page 29 of 46
� 10. Areas where final stabilization has been accomplished and no further construction-
phase permit requirements apply.
S10. NOTICE OF TERNIINATION
A. The site is eligible for termination when either of the following conditions have been met:
1. The site has undergone final stabilization, all temporary BMPs have been removed,
and all stormwater discharges associated with construction activity have been
eliminated; or
2. All portions of the site which have not undergone fmal stabilization per S 10.A.1 have
been sold and/or transferred(per Condition G9),and the Permittee no longer has
operarional control of the construction activity.
B. When the site is eligible for termination, the Permittee shall submit a complete and
accurate Notice of Termination(NOT} form, signed in accordance with General
Condition G2,to:
Department of Ecology
Water Quality Program-Construction Stormwater
PO Box 47696
Olympia,Washington 98504-7696
C. The terxnination is effective on the date the NOT form was received by Ecology,unless �
the Permittee is notified by Ecology within 30 days that termination request is denied
because the eligibility requirements in Condition S 10.A have not been met.
�
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GENERAL CONDITIONS
Gl. DISCHARGE VIOLATIONS �
All discharges and activities authorized by this general permit shall be consistent with the ��,
terms and conditions of this general permit. Any discharge of any pollutant more frequent
than or at a level in excess of that identified and authorized by the general permit sha.11
constitute a violation of the terms and conditions of this permit.
G2. SIGNATORY REQUIREMENTS
A. All pernut applications shall bear a certification of correctness to be signed:
l. In the case of corporations,by a responsible corporate officer of at least the level of
vice president of a corporation;
2. In the case of a partxiership,by a general partner of a partnership;
3. In the case of sole proprietorship,by the proprietor; or
4. In the case of a municipal,state,or other public facility,by either a pri.ncipal
executive officer or ranking elected official.
B. All reports required by this permit and other information requested by Ecology shall be
signed by a person described above or by a duly authorized representative of that person.
A person is a duly authorized representative only i£
1. The authorization is made in writing by a person described above and submitted to
the Ecology.
2. The authorization specifies either an individual or a position having responsibility for
the overall operation of the regulated facility, such as the position of plant manager,
superintendent,position of equivalent responsibility, or an individual or position
having overall responsibility for environmental matters.
C. Changes to authorization. If an authorization under paragraph G2.B.2 above is no longer
accurate because a different individual or position has responsibility for the overall
operation of the facility,a new authorization satisfying the requirements of paragraph
G2.B.2 above shall be submitted to Ecology prior to or together with any reports,
information,or applicarions to be signed by an authorized representative.
D. Certification. Any person signi.ng a document under this section shall make the following
certification: �
"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
Page 31 of 46 '
the information submitted. Based on my inquiry of the person or persons who
manage the system, or those persons directly responsible for gathering
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 i.nformation,including the possibility of fine and
imprisonment for knowing violations."
G3. RIGHT OF INSPECTION AND ENTRY
The Permittee shall allow an authorized representative of Ecology,upon the presentation of
credentials and such other documents as may be required by law:
A. To enter upon the premises where a discharge is located or where any records shall be
kept under the terms and conditions of this permit.
B. To have access to and copy-at reasonable times and at reasonable cost-any records
required to be kept under the terms and conditions of this permit.
C. To inspect-at reasonable times -any facilities, equipment(including monitoring and
control equipment), practices,methods, or operations regulated or required under this
permit.
D. To sample or monitor-at reasonable times-any substances or.parameters at any location
for purposes of assuring permit compliance or as otherwise authorized by the Clean
Water Act.
G4. GENERAL PERNIIT MODIFICATION AND REVOCATION
This permit may be modified,revoked and reissued, or terminated in accordance with the
provisions of Chapter 173-226 WAC. Grounds for modification,revocation and reissuance,
or termination include,but are not limited to, the following:
A. When a change which occurs in the technology or practices for control or abatement of
pollutants applicable to the category of dischargers covered under this permit;
B. When effluent limitation guidelines or standards are promulgated pursuant to the CWA or
Chapter 90.48 RCW, for the category of dischargers covered under this permit;
C. When a water quality management plan containing requirements applicable to the
category of dischargers covered under this permit is approved; or
D. When information is obtained which indicates that cumulative efFects on the environment
from dischargers covered under this permit are unacceptable.
G5. REVOCATION OF COVERAGE L:�1DER THE PERMIT
Pursuant with Chapter 43.21B RCW and Chapter 173-226 WAC,the Director may terminate
coverage for any discharger under this pemut for cause. Cases where coverage may be
teiminated include,but are not limited to, the following:
_ J
Page 32 of 46
A. Violation of any term or condition of this permit;
B. Obtaining coverage under this permit by misrepresentation or failure to disclose fully all
relevant facts;
C. A change in any condition that requires either a temporary or permanent reduction or
elimination of the permitted discharge;
D. Failure or refusal of the Permittee to allow entry as required in RCW 90.48.090;
E. A determination that the permitted activity endangers human health or the environment,
or contributes to water quality standards violations;
F. Nonpayment of permit fees or penalties assessed pursuant to RCW 90.48.465 and
Chapter 173-224 WAC;
G. Failure of the Pernuttee to satisfy the public notice requirements of WAC 173-226-
130(5),when applicable.
The Director may require any discharger under this permit to apply for and obtain coverage
under an individual permit or another more specific general permit. Permittees who have
their coverage revoked for cause according to WAC 173-226-240 may request temporary
coverage under this permit during the time an individual permit is being developed,provided
the request is made within ninety(90) days from the time of revocation and is submitted
along with a complete individual permit application form.
G6. REPORTING A CAUSE FOR MODIFICATION
The Permittee shall submit a new application, or a supplement to the previous application,
whenever a material change to the construction activity or in the quanrity or type of discharge
is anticipated which is not specifically authorized by this permit. This application shall be
submitted at least siacty(60) days prior to any proposed changes. The filing of a request by
the Pemuttee for a permit modification,revocation and reissuance, or termination,or a
notification of planned changes or anticipated noncompliance does not relieve the Permittee
of the duty to comply with the existing permit until it is modified or reissued.
G7. COMPLIANCE WITH OTHER LAWS AND STATUTES
Nothing in this permit shall be construed as excusing the Permittee from compliance with
any applicable federal, state,or local statutes,ordinances, or regulations.
G8. DUTY TO REAPPLY
The Permittee shall apply for permit renewal at least 180 days prior to the specified
expiration date of this permit.
G9. TRANSFER OF GENERAL PERMIT COVERAGE
Coverage under this general permit is automatically transfened to a new discharger,
including operators of lots'parcels within a common plan of development or sale, if:
Page 33 of 46
A. A written, signed agreement(Transfer of Coverage Form)between the current discharger
(Pernuttee) and new discharger contai.ning a specific date for transfer of permit ',
responsibility, coverage,and liability is submitted to the Director, and
B. The Director does not notify the current discharger and new discharger of the Director's
intent to revoke coverage under the general permit. If this norice is not given,the transfer
is effective on the date specified in the written agreement.
When a current discharger(Permittee) transfers a op rtion of a permitted site,the current
discharger shall also submit an updated application form(NOn to the Director indicating the
remaining permitted acreage after the transfer.When a current discharger(Permittee)
transfers all portions of a pemutted site to one or more new dischargers,the current
discharger shall also submit a norice of termination(NOT)form to the Director.
G10.REMOVED SUBSTANCES
Collected screenings, grit, solids, sludges, filter backwash,or other pollutants removed in the
course of treatment or control of stormwater shall not be resuspended or reintroduced to the
final effluent stream for discharge to state waters. �
Gl l.DUTY TO PROVIDE INFORMATION
The Permittee shall submit to Ecology,within a reasonable time,all information which
Ecology may request to determine whether cause exists for modifying,revoking and
reissuing, or ternunating this permit or to determine compliance with this permit. The
Permittee shall also submit to Ecology upon request,copies of records required to be kept by I
this permit[40 CFR 122.41(h)].
G12.OTHER REQUIItEMENTS OF 40 CFR
All other requirements of 40 CFR 122.41 and 122.42 are incorporated in this permit by
reference.
G13.ADDITIONAL MO1vITORING
Ecology may establish specific monitoring requirements in addirion to those contained in this
permit by administrative order or permit modification.
G14.PENALTIES FOR VIOLATING PERNIIT CONDTTIONS
Any person who is found guilty of willfully violating the terms and conditions of this permit
shall be deemed guilty of a crime,and upon conviction thereof shall be punished by a fine of
up to ten thousand dollars($10,000) and costs of prosecution, or by imprisonment in the
discretion of the court. Each day upon which a willful violation occurs may be deemed a
separate and additional violation.
Any person who violates the terms and condirions of a waste discharge permit shall incur, in
addition to any other penalty as provided by law, a civil penalty in the amount of up to ten
Page 34 of 46
thousand dollars($10,000) for every such violation. Each and every such violation shall be a
separate and distinct offense, and in case of a continuing violation, every day's continuance
shall be deemed to be a separate and distinct violation.
G15.UPSET
Definition—"Upset"means an exceptional incident in which there is unintentional and I
temporary noncompliance with technology-based permit effluent limitations because of ',
factors beyond the reasonable control of the Permittee. An upset does not include
noncompliance to the extent caused by operational error, improperly designed treatment
facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or
improper operation.
An upset constitutes an affirmative defense to an action brought for noncompliance with such
technology-based pernut effluent limitations if the requirements of the followin�paragraph
are met.
A Permittee who wishes to establish the affumative defense of upset shall demonstrate,
through properly signed, contemporaneous operating logs or other relevant evidence that: 1)
an upset occurred and that the Permittee can identify the cause(s)of the upset; 2)the
permitted facility was being properly operated at the time of the upset; 3)the Permittee
submitted notice of the upset as required in condition SS.F; and 4)the Permittee complied
with any remedial measures required under this permit.
In any enforcement proceeding,the Permittee seeking to establish the occurrence of an upset
� has the burden of proof.
G16.PROPERTY RIGHTS
This pemut does not convey any property rights of any sort, or any exclusive privilege.
G17.DUTY TO COAZPLY
The Permittee shall comply with all conditions of this permit. Any permit noncompliance
constitutes a violation of the Clean Water Act and is grounds for enforcement action; for
permit termination,revocation and reissuance, or modification; or denial of a permit renewal
application.
G18.TOXIC POLLUTANTS
The Pernuttee shall comply with effluent standards or prohibitions established under Section
307(a) of the Clean Water Act for toxic pollutants withi.n the time provided in the regulations
that establish those standards or prohibitions, even if this pernut has not yet been modified to
incorporate the requirement.
Page 35 of 46
G19.PENALTIES FOR TAMPERING
The Clean Water Act provides that any person who falsifies, tampers with, or knowingly
renders inaccurate any monitoring device or method required to be maintained under this
permit shall,upon conviction,be punished by a fine of not more than$10,000 per violation,
� or by imprisonment for not more than two yea.rs per violation,or by both. If a conviction of
a person is for a violation committed after a first conviction of such person under this
Condition,punishment shall be a fine of not more than$20,000 per day of violation, or
imprisonment of not more than four(4) years, or both.
G20.REPORTING PLANNED CHANGES
The Permittee shall, as soon as possible,give notice to Ecology of planned physical
alterations,modifications or additions to the permitted construction activity,which will result
in:
A. The permitted facility being detemuned to be a new source pursuant to 40 CFR
122.29(b);
B. A significant change in the nature or an increase in quantity of pollutants discharged,
including but not limited to: for sites 5 acres or larger, a 20% or greater increase in
acreage disturbed by construction activity;
C. A change in or addirion of surface water(s)receiving stormwater or non-stormwater from
the construction activity; or
D. A change in the construction plans and/ar activity that affects the Pernuttee's monitoring
requirements in Special Condition S4.
Following such notice,pernut coverage may be modified, or revoked and reissued pursuant
to 40 CFR 122.62(a) to specify and limit any pollutants not previously limited. Until such
modification is effective, any new or increased discharge in excess of pernut limits or not
specifically authorized by this permit constitutes a violation.
G21.REPORTING OTHER INFORMATION
� Where the Permittee becomes aware that it failed to submit any relevant facts in a permit
application, or submitted inconect informarion in a permit application or in any report to
. Ecology, it shall promptly submit such facts or information.
_ G22.REPORTING ANTICIPATED NON-COMPLIANCE
The Perm.ittee sha11 give advance notice to Ecology by submission of a new application or
supplement thereto at least forty-five(45)days prior to commencement of such discharges,
of any facility expansions,production increases, or other planned changes, such as process
; modifications, in the permitted facility or activity which may result in noncompliance«-ith
permit limits or conditions. Any maintenance of facilities,which might necessitate
I��
�
' Page 36 of 46
unavoidable interruption of operation and degradation of effluent quality, shall be scheduled
during non-critical water quality periods and carried out in a manner approved by Ecology. ,
G23.REQUESTS TO BE EXCLUDED FROM COVERAGE UNDER THE PERNIIT
Any discharger authorized by this permit may request to be excluded from coverage under
the general permit by applying for an individual permit. The discharger shall submit to the
Duector an application as described in WAC 173-220-040 or WAC 173-216-070,whichever
is applicable,with reasons supporting the request.These reasons shall fully document how an
individual permit will apply to the applicant in a way that the general permit cannot. Ecology
may make specific requests for information to support the request. The Director shall either
issue an individual pemut or deny the request with a statement explaining the reason for the
denial. When an individual permit is issued to a discharger otherwise subject to the
construction stormwater general permit, the applicability of the construction stormwater
general permit to that Permittee is automatically termi.nated on the effective date of the '
individual pernut.
G24.APPEALS
A. The terms and conditions of this general pernut,as they apply to the appropriate class of
' dischargers, are subject to appeal by any person within 30 days of issuance of this general '
permit, in accordance with Chapter 43.21B RCW, and Chapter 173-226 WAC.
' B. The terms and conditions of this general permit, as they apply to an individual discharger,
' are appealable in accordance with Chapter 43.21B RCW witivn 30 days of the effective
date of coverage of that discharger. Consideration of an appeal of general permit
coverage of an individual discharger is limited to the general permit's applicability or
nonapplicability to that individual discharger.
C. The appeal of general permit coverage of an individual discharger does not affect any
other dischargers covered under this general permit. If the terms and conditions of this
general permit are found to be inapplicable to any individual discharger(s),the matter
shall be remanded to Ecology for consideration of issuance of an individual permit or
permits. '
G25.SEVERABILITY �
The provisions of this permit are severable, and if any provision of this permit,or application
of any provision of this permit to any circumstance, is held invalid,the application of such
provision to other circumstances, and the remainder of this permit shall not be affected
thereby.
G26.BYPASS PROHIBITED
A. Bvuass Procedures
Bypass,which is the intentional diversion of waste streams from any portion of a
treatment facility, is prohibited for stormwater events below the design criteria for
Page 37 of 46
stormwater management. Ecology may take enforcement action against a Permittee for
bypass unless one of the following circumstances (1,2, 3 or 4)is applicable.
1. Bypass of stormwater is consistent with the design criteria and part of an approved
management practice in the applicable stormwater management manual.
2. Bypass for essential maintenance��ithout the potential to cause violation of permit
limits or conditions.
Bypass is authorized if it is for essential maintenance and does not have the potential
to cause violations of limitations or other conditions of this permit, or adversely
impact public health.
3. Bypass of stormwater is unavoidable, unanticipated, and results in noncompliance of
this permit.
This bypass is permitted only if:
a. Bypass is unavoidable to prevent loss of life,personal injury, or severe property
damage. "Severe property damage"means substantial physical damage to
property, damage to the treatment facilities which would cause them to become
inoperable,or substantial and permanent loss of natural resources which can
reasonably be expected to occur in the absence of a bypass;
b. There are no feasible alternatives to the bypass, such as the use of aiixili,ary
treatment facilities,retention of untreated wastes,maintenance during normal
periods of equipment downti.me(but not if adequate backup equipment should
have been installed in the exercise of reasonable engineering judgment to prevent
a bypass which occurred during normal periods of equipment downtime or
preventative maintenance), or transport of untreated wastes to another treatment
facility; and
c. Ecology is properly notified of the bypass as required in Special Condition SS.F
of this permit.
4. A planned action that would cause bypass of stormwater and has the potential to
result in noncompliance of this permit during a storm event.
The Permittee shall notify Ecology at least thirty(30) days before the planned date of
bypass. The notice shall contain:
a. a description of the bypass and its cause;
b. an analysis of all lrnown altematives which would elimi.nate,reduce, or mitigate
the need for bypassing;
c. a cost-effectiveness analysis of alternatives including comparative resource
damage assessment;
d. the m;nimum and maximum duration of bypass under each altemative;
e. a recommendation as to the preferred altemative for conducting the bypass;
Page 38 of 46
f. the projected date of bypass iniriation;
g. a statement of compliance with SEPA;
h. a request for modification of water quality standards as provided for in WAC 173-
201A-110, if an exceedance of any water quality standard is anticipated; and
i. steps taken or planned to reduce, eliminate, and prevent reoccurrence of the
bypass.
5. For probable construction bypasses,the need to bypass is to be identified as early in
the planning process as possible. The analysis required above shall be considered
during preparation of the Stormwater Pollution Prevention Plan(SWPPP)and shall
be included to the extent pracrical. In cases where the probable need to bypass is
determined early,continued analysis is necessary up to and including the construction
period in an effort to minimi�e or eliminate the bypass.
Ecology will consider the following prior to issuing an administrative order for this
type bypass:
a. If the bypass is necessary to perform construction or maintenance-related
' activities essential to meet the requirements of this permit.
b. If there are feasible altematives to bypass, such as the use of auxiliary treatment
facilities,retenrion of untreated wastes, stopping production, maintenance during
normal periods of equipment down time, or transport of untreated wastes to
another treatment facility.
a If the bypass is planned and scheduled to minimize adverse effects on the public
and the environment.
After consideration of the above and the adverse effects of the proposed bypass and
any other relevant factors,Ecology will approve, conditionally approve,or deny the
request. The public shall be notified and given an opportunity to comment on bypass
incidents of significant duration,to the extent feasible. Approval of a request to
bypass will be by admi.nistrative order issued by Ecology under RCW 90.48.120.
B. Du to Miti�
The Permittee is required to take all reasonable steps to minimize or prevent any
discharge or sludge use or disposal in violation of this permit that has a reasonable
likelihood of adversely affecting human health or the environment.
Page 39 of 46
APPENDIX A—DEFINITIONS
AKART is an acronym for"all known,available,and reasonable methods of prevention, control,
and treatment."AKART represents the most current methodology that can be reasonably
required for preventing, controlling,or abating the pollutants and controlling pollution associated
with a discharge.
Applicable TMDL means a TMDL for turbidity, fine sediment, high pH,or phosphorus,which
has been completed and approved by EPA prior to November 16,2005,or prior to the date the
operator's complete permit application is received by Ecology, whichever is later.
A�plicant means an�erator seeking coverage under this permit.
Best ManaQement Practices(BMPs)means schedules of activities,prohibitions of practices,
maintenance procedures, and other physical, structural andlor managerial practices to prevent or
reduce the pollution of waters of the state. BMI's include treatment systems,operating
procedures,and practices to control: stormwater associated with construction activity, spillage
or leaks, sludge or waste disposal, or drainage from raw material storage.
Bu er means an azea designated by a local jurisdiction that is contiguous to and intended to
protect a sensitive area
Bvpass means the intentional diversion of waste streams from any portion of a treatment facility.
' Calendar Week(same as Week means a period of seven consecutive days starting on Sunday.
; Certified Erosion and Sediment Control Lead(CESCL)means a person who has current
' certification through an approved erosion and sediment control training program that meets the
minimum training standards established by Ecology(see BMP C160 in the SWMM).
Clean WaterAct(CWA)means the Federal Water Pollution Control Act enacted by Public Law
92-500, as amended by Public Laws 95-217, 95-576, 96-483, and 97-117; USC 1251 et seq.
Combined Sewer means a sewer which has been designed to serve as a sanitary sewer and a
storm sewer,and into which inflow is allowed by local ordinance.
Common plan ofdevelopment or sale means a site where multiple sepazate and distinct
construction activities may be talang place at different times on different schedules,but still
under a single plan. Examples include: 1)phas.ed projects and projects with multiple filings or
lots, even if the separate phases or filings/lots will be constructed under separate contract or by
separate owners (e.g., a development where lots are sold to separate builders); 2)a development
plan that may be phased over multiple years,but is still under a consistent plan for long-term
development; and 3)projects in a contiguous area that may be unrelated but still under the same
contract, such as construction of a building extension and a new parking lot at the same facility.
Page 40 of 46
If the project is part of a common plan of development or sale,the disturbed area of the entire
plan shall be used in determining permit requirements.
Composite Sample A mixture of grab samples collected at the same sampling point at different
times, formed either by continuous sampling or by mixing discrete samples. May be "time-
composite" (collected at constant time intervals) or"flow-proportional" (collected either as a
constant sample volume at time intervals proportional to stream flow, or collected by increasing
the volume of each aliquot as the flow increases while maintaining a constant time interval
between the aliquots.
Construction Activitv means land disturbing operations including clearing, grading or excavation
which disturbs the surface of the land. Such activities may include road construction,
construction of residential houses,office buildings,or industrial buildings, and demolition
activity.
Demonstrablv Equivalent means that the technical basis for the selection of all stormwater BMPs
is documented within a SWPPP,including:
1. The method and reasons for choosing the stormwater BMPs selected;
2. The pollutant removal performance expected from the BMPs selected;
3. The technical basis supporting the performance claims for the BMPs selected,
including any available data concerni.ng field performance of the BMPs selected;
4. An assessment of how the selected BMPs will comply with state water quality
standards; and
5. An assessment of how the selected BMPs will satisfy both applicable federal
technology-based treatment requirements and state requirements to use all l�own,
available, and reasonable methods of prevention, control, and treahnent(AKART). ,
, Department means the Washington State Department of Ecology. I!
Detention means the temporary storage of stormwater to improve quality and/or to reduce the �,
mass flow rate of discharge.
De-waterin�means the act of pumping ground water or stormwater away from an active
construction site.
Dr�-ector means the Director of the Washington Department of Ecology or his/her authorized ',
representative. ,
Discharger means an owner or operator of any facility or activiry subject to regulation under I
Chapter 90.48 RCW or the Federal Clean Water Act. '
Domestic Wastewater means water carrying human wastes,including kitchen,bath,and laundry
wastes from residences,buildings, industrial establishments,or other places,together with such
ground water infiltration or surface waters as may be present.
Page 41 of 46
Eng,ineer-ed soils The use of soil amendments including,but not limited,to Portland cement
treated base(CTB), cement kiln dust(CKD),or fly ash to achieve certain desirable soil
characteristics.
Equivalent BMPs means operational, source control,treatment, or innovative BMPs which result
in equal or better quality of stormwater discharge to surface water or to ground water than BMPs
selected from the SWMM.
Erosion means the wearing away of the land surface by running water,wind, ice, or other
geological agents,including such processes as gravitational creep.
Erosion and Sediment Control BMPs means BMPs that are intended to prevent erosion and I
sedimentation, such as preserving natural vegetation, seeding,mulchi.ng and matting,plastic
covering, filter fences, sediment traps,and ponds. Erosion and sediment control BMPs are
synonymous with stabilization and struchu-al BMPs.
Final Stabilization (same as, ullv stabilized or.full stabilization)means the establishment of a
permanent vegeta.tive cover,or equivalent permanent stabilization measures(such as riprap,
gabions or geotextiles)which prevents erosion.
Ground Water means water in a saturated zone or stratum beneath the land surface or a surface
water body.
Iniection well means a"���ell"that is used for the subsurface emplacement of fluids. (see y�rel�
Jurisdiction means a political unit such as a city,town or county; incorporated for local self-
government.
Natiofzal Pollutant Dischar,Qe Elimination System (NPDES)means the national program for
issuing,modifying,revoking and reissuing, terminating,monitoring, and enforcing permits,and
imposing and enforcing pretreatment requirements,under sections 307,402, 318,and 405 of the
Federal Clean Water Act, for the dischazge of pollutants to surface waters of the state from point
sources. These permits are referred to as NPDES permits and, in Washington State, are
administered by the Washington Department of Ecology.
Notice oflntent(NOn means the application for, or a request for coverage under this general
permit pursuant to WAC 173-226-200.
Notice ofTermination(I�'OT)means a request for termination of coverage under this general
permit as specified by Special Condition S10 of this permit.
Operator means any party associated with a construction project that meets either of the
following two criteria:
1. The party has operational control over construction plans and specifications, including the
ability to make modifications to those plans and specifications; or
Page 42 of 46
2. The party has day-to-day operational control of those activities at a project which are
necessary to ensure compliance with a SWPPP for the site or other permit conditions(e.g.,they
are authorized to direct workers at a site to carry out activities required by the SWPPP or comply
with other permit conditions).
Out all means the location where stormwater leaves the site. It also includes the location where
stormwater is discharged to a surface waterbody within a site,but does not include discharges to
on-site stormwater treatmendinfiltration devices or storm sewer systems.
Permittee means individual or entity that receives notice of coverage under this general permit.
�H means a liquid's acidity or alkalinity. A pH of 7 is defined as neutral. Large variations above '
or below this value are considered harmful to most aquatic life.
pHMonitorin�Period means the time period in which the pH of stormwater runoff from a site
shall be tested a minimum of once every seven days to determine if stormwater is above pH 8.5.
Point Source means any discernible, confined, and discrete conveyance, including but not
limited to, any pipe, ditch, channel,tunnel, conduit,well, discrete fissure,and container from
which pollutants are or may be discharged to surface waters of the state. This term does not
include return flows from irrigated agriculture. (See Fact Sheet for further explanation.)
Pollutant means dredged spoil, solid waste,incinerator residue,filter backwash, sewage,
garbage, domestic sewage sludge(biosolids),munitions, chemical wastes, biological materials,
radioactive materials,heat,wrecked or discarded equipment,rock, sand,cellar dirt, and
industrial,municipal, and agricultural waste. This term does not include sewage from vessels
�yithin the meaning of section 312 of the CWA,nor does it include dredged or fill material
discharged in accordance with a permit issued under section 404 of the CWA.
Pollution means contamination or other alteration of the physical,chemical, or biological
properties of waters of the state; including change in temperature,taste, color,turbidity, or odor
of the waters; or such discharge of any liquid, gaseous, solid,radioactive or other substance into
any waters of the state as will or is likely to create a nuisance or render such waters harmful,
detrimental or injurious to the public health,safety or welfare;or to domestic,commercial,
industrial, agricultural,recreational, or other legitimate beneficial uses; or to livestock, wild
animals,birds, fish or other aquatic life.
Receivin� Water means the waterbody at the point of discharge. If the discharge is to a storm
sewer system, either surface or subsurface, the receiving water is the waterbody that the storm
sewer system discharges to. Systems designed pri.marily for other purposes such as for ground
water drainage,redirecting stream natural flows, or for conveyance of irrigation water/return
flows that coincidentally convey stormwater are considered the receivi.ng water.
Representative means a stormwater or wastewater sample which represents the flow and
characteristics of the discharge.Representarive samples may be a grab sample, a time-
proportionate composite sample, or a flow proporkionate sample. Ecology's Construction
Stormwater Monitoring Manual provides guidance on representative sampling.
Page 43 of 46
Sanitarv Sewer means a sewer which is designed to convey domestic x�astewater.
Sedime�it means the fragmented material that originates from the weathering and erosion of rocks
or unconsolidated deposits, and is transported by, suspended in, or deposited by water.
Sedimentation mea.ns the depositing or formation of sediment.
Sensitive area means a waterbody,wetland, stream, aquifer recharge area, or channel migration
zone.
SEPA (State Environmental Policy Act)means the Washington State Law, RCVV 43.21C.020,
intended to prevent or eliminate damage to the environment.
SignificantAmount means an amount of a pollutant in a discharge that is amenable to available
and reasonable methods of prevention or treatment; or an amount of a pollutant that has a
reasonable potential to cause a violation of surface or ground water quality or sediment
management standards.
Si�nificant Concrete Work means greater than 1000 cubic yards poured concrete or recycled
concrete.
Si nificant Contributor ofPollutants means a facility determined by Ecology to be a contributor
of a significant amount(s)of a pollutant(s)to waters of the state of Washington.
Site means the land or water area where any"facility or activity" is physically located or
conducted.
Source Control BMPs means physical, structural or mechanical devices or facilities that are
intended to prevent pollutants from entering stormwater. A few examples of source control
BMPs are erosion control pracrices,maintenance of stormwater facilities,constructing roofs over
storage and working areas,and directing wash water and similar discharges to the sanitary sewer ',
or a dead end sump.
Stabilization means the application of appropriate BMPs to prevent the erosion of soils, such as,
temporary and permanent seeding,vegetative covers,mulching and matting,plastic covering and
soddi.ng. See also the defuution of Erosion and Sediment Control BMPs.
Storm Drain means any drain which drains directly into a storm sewer system,usually found ,
along roadways or in parking lots. �
Storna Sewer Svstem means a means a conveyance, or system of conveyances (including roads
with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade
channels, or storm drains designed or used for collecti.ng or conveying stormwater. This does
not include systems which are part of a combined sewer or Publicly Owned Treatment Works
(POTV� as defined at 40 CFR 122.2.
Pa e 44 of 46 I'
g I
Stormwater means that portion of precipitarion that does not naturally percolate into the ground II
or evaporate,but flows via overland flow,mterflow,pipes, and other features of a stormwater li
drainage system into a defined surface water body, or a constructed infiltration facility. �I
Stormwater Mana�ernent Manual(SWMM) or Manual means the technical manual published by
Ecology for use by local governments that contain descriptions of and design criteria for BMPs
to prevent, control,or treat pollutants in stormwater.
Stormwater Pollution Prevention Plan (SWPPP�means a documented plan to implement
measures to identify,prevent,and control the contamination of point source dischazges of
stormwater.
Surface Waters o the State includes lakes,rivers,ponds, streams, inland waters, salt waters, and
all other surface waters and water courses within the jurisdiction of the state of Washi.ngton.
Total Maximum Dailv Load(TMDL1 means a calculation of the maximum amount of a pollutant
that a waterbody can receive and still meet state water quality standards. Percentages of the total
maximum daily load are allocated to the various pollutant sources. A TMDL is the sum of the
allowable loads of a single pollutant from all contributing point and nonpoint sources. The
TMDL calculations shall include a"margin of safety" to ensure that the waterbody can be
protected in case there are unforeseen events or unknown sources of the pollutant. The
calculation shall also account for seasonable variation in water quality.
Treatment BMPs means BMPs that are intended to remove pollutants from stormwater. A few
examples of treatment BMPs are detention ponds, oiUwater separators,biofiltration,and
constructed wetlands.
Transparency means a measurement of water clarity in centimeters (cm),using a 60 cm.
transparency tube. The transpazency tube is used to esti.mate the relative clarity or transparency
of water by noting the depth at which a black and wlute Secchi disc becomes visible when water
is released from a value in the bottom of the tube.A transparency tube is sometimes referred to
as a"turbidity tube".
Turbidi The clarity of«�ater expressed as nephelometric turbidiry units (NTL� and measured
with a calibrated turbidimeter.
Waste Load Allocation (WLA) means the portion of a receiving«�ater's loading capacity that is
allocated to one of its existing or future point sources of pollution. WLAs constitute a type of
water quality based efIluent limitation(40 CFR 130.2{h)).
i�ater Qualitv means the chemical,physical,and biological characteristics of water,usually with
respect to its suitability for a parkicular purpose.
Waters o the State includes those waters as defined as "waters of the United States" in 40 CFR
Subpart 122.2 within the geographic boundaries of Washington State and"waters of the state" as
Page 45 of 46
defined in Chapter 90.48 RCW which include lakes,rivers,ponds, sh�eams, inland waters,
underground waters, salt waters,and all other surface waters and water courses within the
jurisdiction of the state of Washington.
Well means a bored, drilled or driven shaft, or dug hole whose depth is greater than the
largest surface dimension. (see Injection Wel�
i
Page 46 of 46
� APPENDIX B—ACRONYMS
AKART All Known,Available, and Reasonable Methods of Prevention, Control, and
Treatment
BMP Best Management Practice
CESCL Certified Erosion and Sediment Control Lead
� CFR Code of Federal Regulations
CKD Cement Kiln Dust
cm Centimeters
CTB Cement Treated Base
CWA Clean Water Act ,
DMR Discharge Monitoring Report
EPA Environmental Protection Agency
ESC Erosion and Sediment Control
NOI Notice of Intent
NOT Notice of Termination
NPDES National Pollutant Discharge Eliinination System
NTU Nephelometric Turbidity Unit
RCW Revised Code of Washington
SEPA State Environmental Policy Act
SWMM Stormwater Management Manual
SWPPP Stormwater Pollution Prevention Plan
TNIDL Total Maximum Daily Load �
UIC Underground Injection Control ',
USC United States Code �
USEPA United States Environmental Protection Agency I,
WAC Washington Administrative Code
WQ Water Quality
� - WWHM Westem Washington Hydrology Model
Stormwafer Po!lution Prevention Plan �
�
Appendig E — Site Inspection Forms (and Site Log)
The results of each inspection shall be summarized in an inspection report or checklist
that is entered into or attached to the site log book. It is suggested that the inspection
report or checklist be included in this appendix to keep monitoring and inspection
information in one document, but this is optional. However, it is mandatory that this
SWPPP and the site inspection forms be kept onsite at all times during construction, and
that inspections be performed and documented as outlined below.
At a minimum, each inspection report or checklist shall include:
a. Inspection date/times
b. Weather information: general conditions during inspection,
approximate amount of precipitation since the last inspection,
and approximate amount of precipitation within the last 24 hours.
c. A summary or list of all BMPs that have been implemented,
including observations of all erosion/sediment control structures or
practices.
d. The following shall be noted: I
i. locations of BMPs inspected,
ii. locations of BMPs that need maintenance,
iii. the reason maintenance is needed,
iv. locations of BMPs that failed to operate as designed or
intended, and
v. locations where additional or different BMPs are needed, and
the reason(s)why
e. A description of stormwater discharged from the site. The presence
of suspended sediment, turbid water,discoloration, and/or oil
sheen shall be noted, as applicable.
f. A description of any water quality monitoring performed during
,
inspection, and the results of that monitoring.
g. General comments and notes, including a brief description of any
BMP repairs,maintenance or installations made as a result of the
inspection.
;
' h. A statement that, in the judgment of the person conducting the site
inspection, the site is either in compliance or out of compliance
with the terms and conditions of the SWPPP and the NPDES
32
Stormwater Pollution Prevention Plan
permit. If the site inspection indicates that the site is out of
compliance,the inspection report shall include a summary of the
remedial actions required to bring the site back into compliance, as
well as a schedule of implementation.
i. Name, title, and signature of person conducting the site inspection;
and the following statement: "I certify under penalty of law that
this report is true, accurate, and complete, to the best of my
knowledge and belief'.
When the site inspection indicates that the site is not in compliance with any terms and
conditions of the NPDES permit, the Pernuttee shall take immediate action(s)to: stop,
contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance;
correct the problem(s); implement appropriate Best Management Practices (BMPs),
andlor conduct maintenance of existing BMPs; and achieve compliance with all
applicable standards and permit conditions. In addition, if the noncompliance causes a
threat to human health or the environment, the Permittee shall comply with the
Noncompliance Notification requirements in Special Condition SS.F of the permit.
Site Inspection Form
, GeneralInformation
Project Name:
Inspector Name: Title:
CESCL# :
Date: Time:
Inspection Type: ❑ After a rain event
❑ Weekly
❑ Turbidity/transparency benchmark exceedance
❑ Other
�'�'eather
Precipitation Since last inspection In last 24 hours �I�
Description of General Site Conditions: I
Inspection of BMPs
33
Stormwafer Pollution Prevention Plan
Element 1: Mark Clearing Limits
BNIP:
Location �spected Functioning problem/Corrective Action
Y N Y N NIP
��
�
BMP:
Location Inspected Functioning problem/Conective Action
Y N Y N NIP
Elernent 2: Establish Construction Access
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Conective Action
�=.
BMP: I
Location Inspected Functioning problem/Corrective Action !
Y N Y N NIP
Element 3: Control Flow Rates
BMP:
Location �spected Functioning problemJCorrective Action
Y N Y N NIP
BMP:
Inspected Functioning
Location y N Y N NIP Problem/Corrective Action
Element 4: Install Sediment Controls
BMP:
Location �spected Functioning problem/Corrective Action
Y N Y N NIP
34
Sformwater Pollution Preventron Plan
BMP:
Location Inspected Functioning problem/Corrective Action
Y N Y N NIP
�•
�_
BMP:
Location �spected Functioning problem/Corrective Action
Y N Y N NIP
�:_
�
BMP:
Location �SPected Functioning problem/Corrective Action
Y N Y N NIP
BMP:
Location Inspected Functioning problem/Corrective Action
Y N Y N NIP
�
35
Stormwafer Po!lufion Prevention Plan
Ble�nent S: Stabilize Soils
BMP:
Inspected Functioning
Location y N Y N NIP Problem/Corrective Action
BMP:
Location �spected Functioning problem,'Corrective Action
Y N Y N NIP
BMP:
Location Inspected Functioning problem/Corrective Action
Y N Y N NIP
BMP:
Location �spected Functioning problem/Corrective Action
Y N Y N NIP
Element 6: Protect Slopes
BMI':
Inspected Functioning
Location �, N Y N �TIP Problem/Corrective Action
BMP:
Location Inspected Functioning problem/Conective Action
Y N Y N NIP
BMP:
Location �spected Functioning problem/Conective Action
Y N Y N NIP
36
Stormwater Pollution Prevention Plan
�
Element 7: Protect Drain Inlets
BMP: '
Location �spected Functioning problem/Corrective Action '
Y N Y N NIP �
BMP:
Location Inspected Functioning probleriv'Corrective Action
Y N Y N NIP �
BMP:
Location Inspected Functioning problemlCorrective Action
Y N Y I�T NIl'
Element 8: Stabilize Cliannels and Outlets I�
BMP:
Location �spected Functioning problem/Conective Action
Y N Y N NIP '
BMP: �
Location Inspected Functioning problem/Corrective Action
Y N Y N NIP
BMP:
Location Inspected Functioning problem/Corrective Action '
Y N Y N NIP �,
BMP: '
Location ��ected Functioning problem/Corrective Action
Y N Y N NIP
37
�—
Stormwater Pollution Prevention P/an
�
Element 9: Control Pollutants
BMP:
Inspected Functioning
Location �, N Y N �T� Problem/Corrective Action
' .;�::.
�;
BMP:
Location �spected Functioning problemlCorrective Action
Y N Y N NIP
Element 10: Control Dewatering
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
�:
BiVIP:
� Location �spected Functioning problem/Corrective Action
Y N Y N NIP
:�
�
BMP:
Location Inspected Functioning problem/Corrective Action
Y N Y N NIP
38
Stormwater Pollution Prevention Plan
Storm�r�ater Dischar es From the Site
Observed? Problem/Conective Action
Y�N
Location
Turbidity ,
Discoloration
Sheen
Location ,
Turbidity � �!,
Discoloration '�
Sheen �i
39
Stormwater PoUution Prevention Plan
Water Quality Monitorin
Was any water quality monitoring conducted? ❑ Yes ❑ No
If water quality monitoring was conducted, record results here:
If water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6
cm or less, was Ecology notified by phone within 24 hrs?
❑ Yes ❑ �10
If Ecology was notified, indicate the date, time, contact name and phone number
belo��:
Date:
Time:
Contact Name:
Phone ,#:
General Comments and Notes
Include BMP re airs, maintenance, or installations made as a result of the ins ection.
Were Photos Taken? ❑ Yes ❑ �to
If hotos taken, describe hotos below:
40
IStormwater Pollution Prevention Plan
1
' I Appendix F — Engineering Calculations
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