HomeMy WebLinkAbout2023-04-24 Seattle Sounders FC HQ CSWPPP
Construction Stormwater General Permit
Stormwater Pollution Prevention Plan
(SWPPP)
for
Seattle Sounders FC Headquarters & Training Center
Prepared for:
The Washington State Department of Ecology
Northwest Regional Office (Bellevue, WA)
Permittee / Owner Developer Operator / Contractor
Seattle Sounders FC Seattle Sounders FC Venture General Contracting
LLC
Certified Erosion and Sediment Control Lead (CESCL)
Name Organization Contact Phone Number
TBD TBD TBD
SWPPP Prepared By
Name Organization Contact Phone Number
William Andres Coughlin Porter Lundeen 206-343-0460
SWPPP Preparation Date
4/24/2023
Project Construction Dates
Activity / Phase Start Date End Date
Construction 5/2023 12/2023
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Table of Contents
1 Project Information .............................................................................................................. 6
1.1 Existing Conditions ...................................................................................................... 6
1.2 Proposed Construction Activities .................................................................................. 7
2 Construction Stormwater Best Management Practices (BMPs) ........................................... 8
2.1 The 13 Elements .......................................................................................................... 8
2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits ........................................ 8
2.1.2 Element 2: Establish Construction Access ............................................................ 9
2.1.3 Element 3: Control Flow Rates ............................................................................10
2.1.4 Element 4: Install Sediment Controls ...................................................................11
2.1.5 Element 5: Stabilize Soils ....................................................................................12
2.1.6 Element 6: Protect Slopes....................................................................................13
2.1.7 Element 7: Protect Drain Inlets ............................................................................14
2.1.8 Element 8: Stabilize Channels and Outlets ..........................................................15
2.1.9 Element 9: Control Pollutants ...............................................................................16
2.1.10 Element 10: Control Dewatering ..........................................................................20
2.1.11 Element 11: Maintain BMPs .................................................................................21
2.1.12 Element 12: Manage the Project ..........................................................................22
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs .................................25
3 Pollution Prevention Team .................................................................................................26
4 Monitoring and Sampling Requirements ............................................................................27
4.1 Site Inspection ............................................................................................................27
4.2 Stormwater Quality Sampling ......................................................................................27
4.2.1 Turbidity Sampling ...............................................................................................27
4.2.2 pH Sampling ........................................................................................................29
5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies .........................30
5.1 303(d) Listed Waterbodies ..........................................................................................30
5.2 TMDL Waterbodies .....................................................................................................30
6 Reporting and Record Keeping ..........................................................................................31
6.1 Record Keeping ..........................................................................................................31
6.1.1 Site Log Book ......................................................................................................31
6.1.2 Records Retention ...............................................................................................31
6.1.3 Updating the SWPPP ...........................................................................................31
6.2 Reporting ....................................................................................................................32
6.2.1 Discharge Monitoring Reports ..............................................................................32
6.2.2 Notification of Noncompliance ..............................................................................32
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List of Tables
Table 2 – Pollutants ..................................................................................................................16
Table 3 – pH-Modifying Sources ...............................................................................................18
Table 5 – Management .............................................................................................................22
Table 6 – BMP Implementation Schedule .................................................................................24
Table 7 – Team Information ......................................................................................................26
Table 8 – Turbidity Sampling Method ........................................................................................27
List of Appendices
Appendix/Glossary
A. Site Map
B. BMP Detail
C. BMP C101: Preserving Natural Vegetation
· BMP C103: High Visibility Fence
· BMP C105/COR STD 215.00: Stabilized Construction Entrance/Exit
· BMP C106/COR STD 215.00: Wheel Wash
· BMP C120: Temporary and Permanent Seeding
· BMP C123: Plastic Covering
· BMP C140: Dust Control
· BMP C150: Materials on Hand
· BMP C151: Concrete Handling
· BMP C152: Sawcutting and Surfacing Pollution Prevention
· BMP C153: Material Delivery, Storage, and Containment
· BMP C160: Certified Erosion and Sediment Control Lead
· BMP C162: Scheduling
· BMP C220/COR STD 216.30: Storm Drain Inlet Protection
· BMP C233/COR STD 214.00: Silt Fence
· BMP C235/COR STD 213.40: Straw Wattles
· BMP C252: High pH Neutralization Using CO2
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Correspondence
D. Department of Ecology – Northwest Regional Office
3190 160th Avenue SE
Bellevue, WA 98008
425-649-7000
City of Renton – Public Works
11055 S Grandy Way
Renton, WA 98057
425-430-7400
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Site Inspection Form
E. Construction Stormwater General Permit (CSWGP)
F. 303(d) List Waterbodies / TMDL Waterbodies Information
G. Contaminated Site Information
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List of Acronyms and Abbreviations
Acronym / Abbreviation Explanation
303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies
BFO Bellingham Field Office of the Department of Ecology
BMP(s) Best Management Practice(s)
CESCL Certified Erosion and Sediment Control Lead
CO2 Carbon Dioxide
CRO Central Regional Office of the Department of Ecology
CSWGP Construction Stormwater General Permit
CWA Clean Water Act
DMR Discharge Monitoring Report
DO Dissolved Oxygen
Ecology Washington State Department of Ecology
EPA United States Environmental Protection Agency
ERO Eastern Regional Office of the Department of Ecology
ERTS Environmental Report Tracking System
ESC Erosion and Sediment Control
GULD General Use Level Designation
NPDES National Pollutant Discharge Elimination System
NTU Nephelometric Turbidity Units
NWRO Northwest Regional Office of the Department of Ecology
pH Power of Hydrogen
RCW Revised Code of Washington
SPCC Spill Prevention, Control, and Countermeasure
su Standard Units
SWMMEW Stormwater Management Manual for Eastern Washington
SWMMWW Stormwater Management Manual for Western Washington
SWPPP Stormwater Pollution Prevention Plan
TESC Temporary Erosion and Sediment Control
SWRO Southwest Regional Office of the Department of Ecology
TMDL Total Maximum Daily Load
VFO Vancouver Field Office of the Department of Ecology
WAC Washington Administrative Code
WSDOT Washington Department of Transportation
WWHM Western Washington Hydrology Model
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1 Project Information
Project/Site Name: Seattle Sounders FC Headquarters &
Training Center
Street/Location: 1901 Oakesdale Ave SW
City: Renton State: WA Zip code: 98057
Receiving waterbody: Puget Sound
1.1 Existing Conditions
Total acreage (including support activities such as off-site equipment staging yards, material
storage areas, borrow areas).
Total acreage: 13.15
Disturbed acreage: 13.15
Existing structures: 1.37 (existing office building)
Topography: The site slopes generally south-southeast to north-northwest with about a 3-foot
elevation change throughout most of the area. Larger grade differences exist in
localized areas within that plane, especially along the western edge of the
project site which is adjacent to Pond B’s side-slope.
Drainage patterns: Runoff from the site will be conveyed to a new water quality vault, then into
South Pond B. The site discharges to the managed stormwater system within the
Longacres property which was sized and constructed in anticipation of receiving
undetained and untreated runoff from this site. That system drains to
Springbrook Creek in accordance with the Development Agreement and
associated Master Drainage Plan for the Longacres Office Park that was
previously permitted by the City and State. Springbrook Creek, in turn, drains to
the Black River and, ultimately, the Duwamish River and Puget Sound.
Existing Vegetation: There are trees and landscaping throughout the site surrounding the
asphalt parking lots and concrete walkways.
Critical Areas (wetlands, streams, high erosion
risk, steep or difficult to stabilize slopes):
Wetland A is located northwest of the
project limits.
List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the
receiving waterbody: Puget Sound
· Bacteria – Assessment Unit ID: 47122F4I00101
There are no suspected and/or known contaminants associated with the project site.
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1.2 Proposed Construction Activities
Description of site development:
The Seattle Sounders FC Headquarters & Training Center Project proposes to build (4) sports
fields by eveloped upon existing open grass fields, portions of a parking lot, and a
decommissioned helicopter pad. Existing swales and ponds located on the site will not be
encroached upon for this project
Description of construction activities:
Site development will include asphalt paving, landscaping, concrete sidewalk and installation,
excavation for 584,020 fubic feet of floodplain mitigation, and the construction of the (4) sport
fields and associated infrastructure.
Description of site drainage including flow from and onto adjacent properties. Must be consistent
with Site Map in Appendix A:
This project proposes to construct a drainage system with a new network of underground pipes
and catch basins to collect surface water runoff throughout the site and direct it to a water
quality treatment facility that will be constructed adjacent to an existing detention pond (Pond B)
which exists on the property. Treated water from that facility will flow into Pond B, along with
higher storm events that are not subject to the requirements for water quality treatment. Pond B
was designed for the Boeing Master Plan and was constructed to accommodate the full
detention requirements for the overall Longacres Campus, of which this Sounders Field
Complex site is a part. From Pond B, the storm runoff flows into the North Pond (Pond A) via a
flow control facility which in turn flows out to Springbrook Creek and ultimately the Duwamish
River. This system is consistent with the conditions of the original Longacres Development
Agreement with the City which was the basis for the existing development on the property.
Additionally, a series of underground storage chambers (StormTech or Eq) is proposed to
provide the flood plain fill mitigation volume.
Description of final stabilization:
Native landscape shrubs and trees are being retained where feasible. All areas on-site will be
stabilized with either paving or landscape areas.
Contaminated Site Information:
There are no contaminated areas on-site.
Proposed activities regarding contaminated soils or groundwater:
Not applicable.
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2 Construction Stormwater Best Management Practices (BMPs)
The SWPPP is a living document reflecting current conditions and changes throughout the life
of the project. These changes may be informal (i.e., hand-written notes and deletions). Update
the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design.
2.1 The 13 Elements
2.1.1 Element 1: Preserve Vegetation / 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 shall 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:
· BMP C101: Preserving Natural Vegatation
· BMP C103: High-Visability Fence
· BMP C233/COR STD 214.00: Silt Fence
Installation Schedules: The high visibility fencing, silt fencing, and natural vegetation protection
shall be installed at the beginning of construction to ensure that the above listed areas are
preserved to the maximum extent possible through the duration of construction activities.
Inspection and Maintenance plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
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2.1.2 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. Wheel washing, street sweeping, and street cleaning shall be employed as necessary 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:
· BMP C105/COR STD 215.00: Stabilized Construction Access
· BMP C106/COR STD 215.00: Wheel Wash
Installation Schedules: The project will utilize the existing paved access driveways, onsite
hardscape, and asphalt parking areas for access and staging. Quarry spall access roads are not
recommended or necessary. The stabilized construction access shall be available via the
existing site driveways at the start of construction and will be utilized to the maximum extent
possible through the duration of construction activities.
Inspection and Maintenance Plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
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2.1.3 Element 3: Control Flow Rates
Will you construct stormwater retention and/or detention facilities?
Yes No
Will you use permanent infiltration ponds or other low impact development (example: rain
gardens, bio-retention, porous pavement) to control flow during construction?
Yes No
In order to protect the properties and waterways downstream of the project site,
stormwater discharge from the site will be controlled. 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. The specific BMPs for flow
control that shall be used on this project include:
· BMP C235/COR STD 213.40: Straw Wattles
See Appendix B – Construction BMPs for BMP details.
Installation Schedules: Wattles shall be installed at the beginning of construction activities to
ensure the protection of onsite areas downstream of the clearing area to the maximum extent
possible.
Inspection and Maintenance Plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
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2.1.4 Element 4: Install Sediment Controls
All stormwater runoff from disturbed areas shall pass through appropriate sediment removal
BMPs 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:
· BMP C233/COR STD 214.00: Silt Fence
· BMP C235/COR STD 213.40: Straw Wattles
See Appendix B – Construction BMPs for BMP details.
In addition, sediment will 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.
Installation Schedules: Silt fence and straw wattles shall be installed at the beginning of
construction activities to ensure onsite areas downstream of the clearing area are protected to
the maximum extent possible.
Inspection and Maintenance Plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
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2.1.5 Element 5: Stabilize Soils
West of the Cascade Mountains Crest
Season Dates Number of Days Soils Can
be Left Exposed
During the Dry Season May 1 – September 30 7 days
During the Wet Season October 1 – April 30 2 days
Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on
the weather forecast.
Anticipated project dates: Start date: 4/2023 End date: 12/2023
Will you construct during the wet season?
Yes No
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:
· BMP C120: Temporary and Permanent Seeding
· BMP C123: Plastic Covering
· BMP C140: Dust Control
See Appendix B – Construction BMPs for BMP details.
In general, exposed soils 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. Construction activities shall be scheduled in a
way that limits the amount of time soil is exposed throughout the duration of the project.
Installation Schedules: Soil stabilization BMPs shall be installed and maintained starting at the
beginning of construction as soon as soils are exposed, and throughout construction activities
for as long as they are exposed during the designated time frames listed above to ensure they
are utilized to the maximum extent possible through the duration of construction activities.
Inspection and Maintenance Plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
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2.1.6 Element 6: Protect Slopes
Will steep slopes be present at the site during construction?
Yes No
All temporary stockpile slopes will be designed, constructed, and protected in a manner that
minimizes erosion. The following BMPs will be used to protect slopes for this project:
· BMP C120: Temporary and Permanent Seeding
· BMP C123: Plastic Covering
See Appendix B – Construction BMPs for BMP details.
Installation Schedules: Slope protection BMPs shall be installed and maintained starting at the
beginning of construction as soon as soils are exposed, and throughout construction activities
for as long as they are exposed during the designated time frames listed above to ensure they
are utilized to the maximum extent possible through the duration of construction activities.
Inspection and Maintenance Plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
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2.1.7 Element 7: Protect Drain Inlets
All storm drain inlets made operable during construction shall be protected to prevent unfiltered
or untreated water from entering the drainage conveyance system. The following inlet protection
measures will be applied on this project:
BMP C220/COR STD 216.30: Storm Drain Inlet Protection
See Appendix B – Construction BMPs for BMP details.
Installation Schedules: Storm drain inlet protection shall be installed at the beginning of
construction, as no grading or construction is required prior to their installation.
Inspection and Maintenance plan: Inlet protection will be cleaned (or removed and replaced)
when sediment has filled the device by one third (1/3) or as specified by the manufacturer. Inlets
will be inspected weekly at a minimum and daily during storm events.
Inspection and Maintenance Plan to be prepared by contractor in accordance with the BMP
details (appendix B) from Volume II of the State of Washington Department of Ecology’s 2019
Stormwater Management Manual for Western Washington.
Responsible Staff: CESCL
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2.1.8 Element 8: Stabilize Channels and Outlets
There will be no temporary on-site conveyance channels for the civil scope of this project. No
onsite channels exist within the project site nor the immediately surrounding areas.
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: CESCL
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2.1.9 Element 9: Control Pollutants
The following pollutants are anticipated to be present on-site:
Table 2 – Pollutants
Pollutant (List pollutants and source, if applicable)
Vehicle, Construction Equipment, and Petroleum Storage/Dispensing: Petroleum
Chemical Storage: Agricultural Chemicals, Fertilizer, Pesticides
Demolition: Dust, Soil, Debris
Concrete and Grout
Vehicles, construction equipment, and/or petroleum product storage/dispensing:
All vehicles, equipment, and petroleum product storage/dispensing areas will be
inspected regularly to detect any leaks or spills, and to identify maintenance needs to
prevent leaks or spills.
On-site fueling tanks and petroleum product storage containers shall include secondary
containment.
Spill prevention measures, such as drip pans, will be used when conducting
maintenance and repair of vehicles or equipment.
In order to perform emergency repairs on site, temporary plastic will be placed beneath
and, if raining, over the vehicle.
Contaminated surfaces shall be cleaned immediately following any discharge or spill
incident.
Chemical storage:
BMP C153: Material Delivery, Storage and Containment
Any chemicals stored in the construction areas will conform to the
appropriate source control BMPs listed in Volume IV of the Ecology
stormwater manual. In Western WA, all chemicals shall have cover,
containment, and protection provided on site.
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 procedures and rates shall be followed.
Demolition:
BMP C140: Dust Control:
Dust released from demolished sidewalks, buildings, or structures will be
controlled using Dust Control measures.
BMP C220/COR STD 216.30: Storm Drain Inlet Protection
Storm drain inlets vulnerable to stormwater discharge carrying dust, soil,
or debris will be protected using Storm Drain Inlet Protection.
BMP C152: Sawcutting and Surfacing Pollution Prevention
Process water and slurry resulting from saw cutting and surfacing
operations will be prevented from entering the waters of the State by
implementing Sawcutting and Surfacing Pollution Prevention measures.
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Concrete and grout:
BMP C151: Concrete Handling
Process water and slurry resulting from concrete work will be prevented
from entering the waters of the state by implementing Concrete Handling
measures.
Other:
Other BMPs will be administered as necessary to address any additional
pollutant sources on site.
The specific BMPs for control pollutants to be used on-site shall be implemented as
needed and include:
BMP C140: Dust Control
BMP C151: Concrete Handling
BMP C152: Sawcutting and Surfacing Pollution Prevention
BMP C153: Material Delivery, Storage, and Containment
BMP C220/COR STD 216.30: Storm Drain Inlet Protection
See Appendix B – Construction BMPs for BMP details.
Installation Schedules: The above listed BMPs shall be implemented as the need arises,
depending on the pollutant they will mitigate, so as to reduce the possibility of pollutants off and
on-site.
Inspection and Maintenance plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site?
Yes No
Will wheel wash or tire bath system BMPs be used during construction?
Yes No
Wheel washing, street sweeping, and street cleaning shall be employed as necessary 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:
· BMP C106/COR STD 215.00: Wheel Wash
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Installation Schedules: The project will utilize the existing paved access driveways, onsite
hardscape, and asphalt parking areas for access and staging. Quarry spall access roads are not
recommended or necessary. The stabilized construction access shall be available via the
existing site driveways at the start of construction and will be utilized to the maximum extent
possible through the duration of construction activities.
Inspection and Maintenance Plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
Will pH-modifying sources be present on-site?
Yes No If yes, check the source(s).
Table 3 – pH-Modifying Sources
None
Bulk cement
Cement kiln dust
Fly ash
Other cementitious materials
New concrete washing or curing waters
Waste streams generated from concrete grinding and sawing
Exposed aggregate processes
Dewatering concrete vaults
Concrete pumping and mixer washout waters
Recycled concrete
Recycled concrete stockpiles
Other (i.e., calcium lignosulfate) [please describe: ]
Where pH-modifying sources may be encountered, steps must be taken to prevent pollutants
from contaminating stormwater and raising the pH level above 8.5. The acceptable pH range for
stormwater is between 6.5 and 8.5, beyond that, pH neutralization must occur. The specific
BMPs for pH modification that shall be used on this project include:
· BMP C252: High pH Neutralization Using CO2
See Appendix B – Construction BMPs for BMP details.
Installation Schedules: The above listed BMP shall be implemented as soon as a stormwater pH
reaches higher than 8.5, which typically occurs when the aforementioned pH-modifying sources
come into contact with stormwater.
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Inspection and Maintenance plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches,
streets, or streams. Excess concrete must not be dumped on-site, except in designated
concrete washout areas with appropriate BMPs installed.
Will uncontaminated water from water-only based shaft drilling for construction of building, road,
and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits
discharge to surface waters?
Yes No
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2.1.10 Element 10: Control Dewatering
No dewatering is anticipated for civil scope of this project.
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: CESCL
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2.1.11 Element 11: Maintain BMPs
All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained
and repaired as needed to ensure continued performance of their intended function.
Maintenance and repair shall be conducted in accordance with each particular BMP
specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW).
Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar
week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the
site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to
once every calendar month.
All temporary ESC BMPs shall be removed within 30 days after final site stabilization is
achieved or after the temporary BMPs are no longer needed.
Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal
of either BMPs or vegetation shall be permanently stabilized.
Additionally, protection must be provided for all BMPs installed for the permanent control of
stormwater from sediment and compaction. BMPs that are to remain in place following
completion of construction shall be examined and restored to full operating condition. If
sediment enters these BMPs during construction, the sediment shall be removed and the facility
shall be returned to conditions specified in the construction documents.
List and describe BMPs:
BMP C150: Materials on Hand
BMP C160: Certified Erosion and Sediment Control Lead
See Appendix B – Construction BMPs for BMP details.
Installation Schedules: Establish BMP at the start of construction.
Inspection and Maintenance plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
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2.1.12 Element 12: Manage the Project
The project will be managed based on the following principles:
· Projects will be phased to the maximum extent practicable and seasonal work limitations
will be taken into account.
· Inspection and monitoring:
o Inspection, maintenance and repair of all BMPs will occur as needed to ensure
performance of their intended function.
o Site inspections and monitoring will be conducted in accordance with Special
Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map.
Sampling station(s) are located in accordance with applicable requirements of
the CSWGP.
· Maintain an updated SWPPP.
o The SWPPP will be updated, maintained, and implemented in accordance with
Special Conditions S3, S4, and S9 of the CSWGP.
As site work progresses the SWPPP will be modified routinely to reflect changing site
conditions. The SWPPP will be reviewed monthly to ensure the content is current.
Table 5 – Management
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 earthwork during the dry season
Other (please describe)
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:
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.
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
(BMP C162).
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Coordination with 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.
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.
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Table 6 – BMP Implementation Schedule
Phase of Construction
Project
Stormwater BMPs Date Wet/Dry
Season
Start of Construction C101 04/2023 Wet
Start of Construction C103 04/2023 Wet
Start of Construction C105/COR STD 215.00 04/2023 Wet
Start of Construction C106/COR STD 215.00 04/2023 Wet
Start of Construction C120 04/2023 Wet
Start of Construction C123 04/2023 Wet
As Needed C140 N/A Dry
As Needed C150 N/A Dry
As Needed C151 N/A Dry
As Needed C152 N/A Dry
As Needed C153 N/A Dry
Start of Construction C160 04/2023 Wet
Start of Construction C162 04/2023 Wet
Start of Construction C220/COR STD 216.30 04/2023 Wet
Start of Construction C233/COR STD 214.00 04/2023 Wet
Start of Construction C235/COR STD 213.40 04/2023 Wet
Start of Construction C252 04/2023 Wet
P a g e | 25
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs
No proposed LID BMP measures are located on site.
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: CESCL
P a g e | 26
3 Pollution Prevention Team
Table 7 – Team Information
Title Name(s) Phone Number
Certified Erosion and
Sediment Control Lead
(CESCL)
TBD TBD
Resident Engineer Tim Brockway, P.E. 206-343-0460
Emergency Ecology
Contact
TBD TBD
Emergency Permittee/
Owner Contact
Tom Chiado 206-550-8363
Non-Emergency Owner
Contact
TBD TBD
Monitoring Personnel TBD TBD
Ecology Regional Office Northwest Regional Office 425-649-7000
P a g e | 27
4 Monitoring and Sampling Requirements
Monitoring includes visual inspection, sampling for water quality parameters of concern, and
documentation of the inspection and sampling findings in a site log book. A site log book will be
maintained for all on-site construction activities and will include:
· A record of the implementation of the SWPPP and other permit requirements
· Site inspections
· Stormwater sampling data
The site log book must be maintained on-site within reasonable access to the site and be made
available upon request to Ecology or the local jurisdiction.
Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See
CSWGP Special Condition S8 and Section 5 of this template.
4.1 Site Inspection
Site inspections will be conducted at least once every calendar week and within 24 hours
following any discharge from the site. For sites that are temporarily stabilized and inactive, the
required frequency is reduced to once per calendar month.
The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with
the applicable requirements of the CSWGP.
4.2 Stormwater Quality Sampling
4.2.1 Turbidity Sampling
Requirements include calibrated turbidity meter or transparency tube to sample site discharges
for compliance with the CSWGP. Sampling will be conducted at all discharge points at least
once per calendar week.
Method for sampling turbidity:
Table 8 – Turbidity Sampling Method
Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size)
Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size)
The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency
less than 33 centimeters.
If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to
or greater than 6 cm, the following steps will be conducted:
1. Review the SWPPP for compliance with Special Condition S9. Make appropriate
revisions within 7 days of the date the discharge exceeded the benchmark.
P a g e | 28
2. Immediately begin the process to fully implement and maintain appropriate source
control and/or treatment BMPs as soon as possible. Address the problems within 10
days of the date the discharge exceeded the benchmark. If installation of necessary
treatment BMPs is not feasible within 10 days, Ecology may approve additional time
when the Permittee requests an extension within the initial 10-day response period.
3. Document BMP implementation and maintenance in the site log book.
If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following
steps will be conducted:
1. Telephone or submit an electronic report to the applicable Ecology Region’s
Environmental Report Tracking System (ERTS) within 24 hours.
· Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan,
Yakima): (509) 575-2490 or
http://www.ecy.wa.gov/programs/spills/forms/nerts_online/CRO_nerts_online.html
· Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant,
Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400
or http://www.ecy.wa.gov/programs/spills/forms/nerts_online/ERO_nerts_online.html
· Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish,
Whatcom): (425) 649-7000 or
http://www.ecy.wa.gov/programs/spills/forms/nerts_online/NWRO_nerts_online.html
· Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis,
Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 or
http://www.ecy.wa.gov/programs/spills/forms/nerts_online/SWRO_nerts_online.html
2. Immediately begin the process to fully implement and maintain appropriate source
control and/or treatment BMPs as soon as possible. Address the problems within 10
days of the date the discharge exceeded the benchmark. If installation of necessary
treatment BMPs is not feasible within 10 days, Ecology may approve additional time
when the Permittee requests an extension within the initial 10-day response period
3. Document BMP implementation and maintenance in the site log book.
4. Continue to sample discharges daily until one of the following is true:
· Turbidity is 25 NTU (or lower).
· Transparency is 33 cm (or greater).
· Compliance with the water quality limit for turbidity is achieved.
o 1 - 5 NTU over background turbidity, if background is less than 50 NTU
o 1% - 10% over background turbidity, if background is 50 NTU or greater
· The discharge stops or is eliminated.
P a g e | 29
4.2.2 pH Sampling
pH monitoring is not required since this project does not involve “significant concrete work” (less
than 1000 cubic yards poured concrete over the life of the project).
P a g e | 30
5 Discharges to 303(d) or Total Maximum Daily Load (TMDL)
Waterbodies
5.1 303(d) Listed Waterbodies
Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH?
Yes No
List the impairment(s):
· Bacteria – Assessment Unit ID: 47122F4I00101
5.2 TMDL Waterbodies
In order to protect the properties and waterways downstream of the project site and remain
TMDL compliant, stormwater discharges from the site will be controlled.
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
combined sewer systems).
Installation Schedules: Existing detention facilities shall be inspected to ensure they are
functioning properly before constructing site improvements.
Inspection and Maintenance plan: Inspection and Maintenance Plan to be prepared by
contractor in accordance with the BMP details (appendix B) from Volume II of the State of
Washington Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
Responsible Staff: CESCL
Discharges to TMDL receiving waterbodies will meet in-stream water quality criteria at the point
of discharge.
P a g e | 31
6 Reporting and Record Keeping
6.1 Record Keeping
6.1.1 Site Log Book
A site log book will be maintained for all on-site construction activities and will include:
· A record of the implementation of the SWPPP and other permit requirements
· Site inspections
· Sample logs
6.1.2 Records Retention
Records will be retained during the life of the project and for a minimum of three (3) years
following the termination of permit coverage in accordance with Special Condition S5.C of the
CSWGP.
Permit documentation to be retained on-site:
· CSWGP
· Permit Coverage Letter
· SWPPP
· Site Log Book
Permit documentation will be provided within 14 days of receipt of a written request from
Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when
requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP.
6.1.3 Updating the SWPPP
The SWPPP will be modified if:
· Found ineffective in eliminating or significantly minimizing pollutants in stormwater
discharges from the site.
· 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.
·
The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine
additional or modified BMPs are necessary for compliance. An updated timeline for BMP
implementation will be prepared.
P a g e | 32
6.2 Reporting
6.2.1 Discharge Monitoring Reports
Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring
Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given
monitoring period the DMR will be submitted as required, reporting “No Discharge”. The DMR
due date is fifteen (15) days following the end of each calendar month.
DMRs will be reported online through Ecology’s WQWebDMR System.
6.2.2 Notification of Noncompliance
If any of the terms and conditions of the permit is not met, and the resulting noncompliance may
cause a threat to human health or the environment, the following actions will be taken:
1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable
Regional office ERTS phone number (Regional office numbers listed below).
2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or
correct the noncompliance. If applicable, sampling and analysis of any noncompliance
will be repeated immediately and the results submitted to Ecology within five (5) days of
becoming aware of the violation.
3. A detailed written report describing the noncompliance will be submitted to Ecology
within five (5) days, unless requested earlier by Ecology.
Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6
cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as
required by Special Condition S5.A of the CSWGP.
· Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit,
Snohomish, or Whatcom County
Include the following information:
1. Your name and / Phone number
2. Permit number
3. City / County of project
4. Sample results
5. Date / Time of call
6. Date / Time of sample
7. Project name
In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will
be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH
water.
P a g e | 33
Appendix/Glossary
A. Site Map
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SDx(NOT INCLUDED)100 YEAR FLOODPLAINELEVATIONBFE=20.0100 YEAR FLOODPLAINELEVATIONBFE=20.0100 YEAR FLOODPLAINELEVATIONBFE=20.0040801601"=80'801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTERED PROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON13ROVERALL TESC PLAN
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20TREEPROTECTION(TYP)TREEPROTECTION(TYP)TREEPROTECTION(TYP)100 FT POND "A"WETLANDBUFFERWETLAND AΔZONEAESDxSDxSDxSDxΔZONEAESDxSDxSDxSDx801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN14RCONTINUED - SEE SHEET C2.04CONTINUED - SEE SHEET C2.02
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SDxSDxSDxSDxSDx100 FT POND "A"WETLANDBUFFER801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN15RCONTINUED - SEE SHEET C2.05CONTINUED - SEE SHEET C2.03
CONTINUED - SEE SHEET C2.01
1901 OAKESDALE AVE SW
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20TREEPROTECTION(TYP)100 FT POND"A" WETLANDBUFFERPOND BXXXXXXSDx SDx SDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx
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SDxSDxSDx801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN16RCONTINUED - SEE SHEET C2.07CONTINUED - SEE SHEET C2.05 CONTINUED - SEE SHEET C2.01
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20INLETPROTECTION(TYP)WHEEL WASHCONSTRUCTIONENTRANCESEE DETAILPOTENTIALSTOCKPILE/LAYDOWN AREACONSTRUCTIONENTRANCE AND GATESEE DETAIL1C2.201C2.20SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxWxWxWxWxWxWxWxWxWxWxWxWxWxWxWx801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN17RCONTINUED - SEE SHEET C2.08CONTINUED - SEE SHEET C2.06
CONTINUED - SEE SHEET C2.04
CONTINUED - SEE SHEET C2.021901 OAKESDALE AVE SW
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20PROTECTEXISTING PONDINSTALL WEIGHTED PLASTICSHEETING UP TO WATER LINE.ADJUST LIMITS AS NEEDEDFOR WALL CONSTRUCTIONFILTER AND FABRIC FENCE TO BEINSTALLED AROUND THE EXISTINGWATER FEATURESTREEPROTECTION(TYP)POND BSDxSDxSDx SDx SDxSDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDxSDx SDx SDx SDx SDxSDxSDxSDxSDxSDxSDx801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN18RCONTINUED - SEE SHEET C2.10CONTINUED - SEE SHEET C2.08 CONTINUED - SEE SHEET C2.04
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20INLETPROTECTION(TYP)POTENTIALSTOCKPILE/LAYDOWN AREAWHEEL WASHCONSTRUCTIONENTRANCESEE DETAILCONSTRUCTIONENTRANCEAND GATE1C2.20SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSD
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SDxSDx801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN19RCONTINUED - SEE SHEET C2.11CONTINUED - SEE SHEET C2.07
CONTINUED - SEE SHEET C2.05CONTINUED - SEE SHEET C2.09
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20OAKESDALE AVE SWINLETPROTECTION(TYP)OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPx OHPxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx
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SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx SDx801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN20RCONTINUED - SEE SHEET C2.08
CONTINUED - SEE SHEET C2.06
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20PROTECTEXISTING PONDPROTECTEXISTING PONDINSTALL WEIGHTED PLASTICSHEETING UP TO WATER LINE.ADJUST LIMITS AS NEEDEDFOR WALL CONSTRUCTIONFILTER AND FABRIC FENCE TO BEINSTALLED AROUND THE EXISTINGWATER FEATURES. ONCE GRADINGHAS COMPLETED, TESC FENCINGSHALL MATCH SHOWN LIMITS.INSTALL WEIGHTED PLASTICSHEETING UP TO WATER LINE.ADJUST LIMITS AS NEEDEDFOR WALL CONSTRUCTIONFILTER AND FABRIC FENCE TO BEINSTALLED AROUND THE EXISTINGWATER FEATURES. ONCE GRADINGHAS COMPLETED, TESC FENCINGSHALL MATCH SHOWN LIMITS.POND B100 YEARFLOODPLAINELEVATIONLOT LINE ADJUSTMENTFOR SOUNDERSHEADQUARTERSSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx
SDxSDxSDxSDxSDxSDxSDxSDxSDxSDxSDx SDx SDx SDx SDx SDx SDx SDx
SDxSDxSDxSDxSDx801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN21RCONTINUED - SEE SHEET C2.11 CONTINUED - SEE SHEET C2.07
LegendPROPERTY LINELIMITS OF CONSTRUCTIONINTERCEPTOR SWALEFILTER FABRIC FENCINGDo not use BlockEdit, Use LEGEND to editTEMPORARY STORM PIPETEMPORARY SWALETREE PROTECTIONINLET PROTECTIONSTRAW WATTLESWETLANDPOTENTIAL STOCKPILELAYDOWN AREACONSTRUCTIONENTRANCE TEMPOARYTEMPORARYCONSTRUCTION GATECONSTRUCTIONFENCING TEMPORARYWEIGHTED PLASTICSHEETING7C2.2012C2.208C2.206C2.205C2.201C2.20100 YEARFLOODPLAINELEVATIONZONE XZONE X801 SECOND AVENUE, SUITE 900 (206) 343-0460 SEATTLE, WA 98104 www.cplinc.com COUGHLIN LUNDEEN PORTER E N G I N E E R I N G S E I S M I C C I V I L S T R U C T U R A L 33708STATE OF WASHINGTONREGISTEREDPROFESSIONALENGINEER CORB.BYHTOMITYAWK
A PORTION OF THE NW 1/4 OF SECTION 8, TOWNSHIP 23N, RANGE 5E, W.M.Call Before You Dig. 8-1-1 or 1-800-424-5555 Underground Service (USA)TED-40-4238
SEATTLE SOUNDERS FC HEADQUARTERS& TRAINING CENTERRENTON, WASHINGTONSEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER
LUA22-000357 C22005747SEATTLE SOUNDERS FC HEADQUARTERS & TRAINING CENTER -4238PR22-000301CITY OFRENTON01020401"=20'TESC PLAN22RCONTINUED - SEE SHEET C2.10
CONTINUED - SEE SHEET C2.08CONTINUED - SEE SHEET C2.12
P a g e | 34
B. BMP Detail
· BMP C101: Preserving Natural Vegetation
· BMP C103: High Visibility Fence
· BMP C105/COR STD 215.00: Stabilized Construction Entrance/Exit
· BMP C106/COR STD 215.00: Wheel Wash
· BMP C120: Temporary and Permanent Seeding
· BMP C123: Plastic Covering
· BMP C140: Dust Control
· BMP C150: Materials on Hand
· BMP C151: Concrete Handling
· BMP C152: Sawcutting and Surfacing Pollution Prevention
· BMP C153: Material Delivery, Storage, and Containment
· BMP C160: Certified Erosion and Sediment Control Lead
· BMP C162: Scheduling
· BMP C220/COR STD 216.30: Storm Drain Inlet Protection
· BMP C233/COR STD 214.00: Silt Fence
· BMP C235/COR STD 213.40: Straw Wattles
· BMP C252: High pH Neutralization Using CO2
BMP C101: Preserving Natural Vegetation
Purpose
The purpose of preserving natural vegetation is to reduce erosion wherever practicable. Limiting site
disturbance is the single most effective method for reducing erosion. For example, conifers can hold
up to about 50 percent of all rain that falls during a storm. Up to 20-30 percent of this rain may never
reach the ground but is taken up by the tree or evaporates. Another benefit is that the rain held in the
tree can be released slowly to the ground after the storm.
Conditions of Use
Natural vegetation should be preserved on steep slopes, near perennial and intermittent water-
courses or swales, and on building sites in wooded areas.
l As required by local governments.
l Phase construction to preserve natural vegetation on the project site for as long as possible
during the construction period.
Design and Installation Specifications
Natural vegetation can be preserved in natural clumps or as individual trees, shrubs and vines.
The preservation of individual plants is more difficult because heavy equipment is generally used to
remove unwanted vegetation. The points to remember when attempting to save individual plants
are:
l Is the plant worth saving? Consider the location, species, size, age, vigor, and the work
involved. Local governments may also have ordinances to save natural vegetation and trees.
l Fence or clearly mark areas around trees that are to be saved. It is preferable to keep ground
disturbance away from the trees at least as far out as the dripline.
Plants need protection from three kinds of injuries:
l Construction Equipment - This injury can be above or below the ground level. Damage results
from scarring, cutting of roots, and compaction of the soil. Placing a fenced buffer zone around
plants to be saved prior to construction can prevent construction equipment injuries.
l Grade Changes - Changing the natural ground level will alter grades, which affects the plant's
ability to obtain the necessary air, water, and minerals. Minor fills usually do not cause prob-
lems although sensitivity between species does vary and should be checked. Trees can typ-
ically tolerate fill of 6 inches or less. For shrubs and other plants, the fill should be less.
When there are major changes in grade, it may become necessary to supply air to the roots of
plants. This can be done by placing a layer of gravel and a tile system over the roots before the
fill is made. The tile system should be laid out on the original grade leading from a dry well
2019 Stormwater Management Manual for Western Washington
Volume II -Chapter 3 -Page 271
around the tree trunk. The system should then be covered with small stones to allow air to cir-
culate over the root area.
Lowering the natural ground level can seriously damage trees and shrubs. The highest per-
centage of the plant roots are in the upper 12 inches of the soil and cuts of only 2-3 inches can
cause serious injury. To protect the roots it may be necessary to terrace the immediate area
around the plants to be saved. If roots are exposed, construction of retaining walls may be
needed to keep the soil in place. Plants can also be preserved by leaving them on an undis-
turbed, gently sloping mound. To increase the chances for survival, it is best to limit grade
changes and other soil disturbances to areas outside the dripline of the plant.
l Excavations - Protect trees and other plants when excavating for drainfields, power, water,
and sewer lines. Where possible, the trenches should be routed around trees and large
shrubs. When this is not possible, it is best to tunnel under them. This can be done with hand
tools or with power augers. If it is not possible to route the trench around plants to be saved,
then the following should be observed:
o Cut as few roots as possible. When you have to cut, cut clean. Paint cut root ends with a
wood dressing like asphalt base paint if roots will be exposed for more than 24-hours.
o Backfill the trench as soon as possible.
o Tunnel beneath root systems as close to the center of the main trunk to preserve most
of the important feeder roots.
Some problems that can be encountered with a few specific trees are:
l Maple, Dogwood, Red alder, Western hemlock, Western red cedar, and Douglas fir do not
readily adjust to changes in environment and special care should be taken to protect these
trees.
l The windthrow hazard of Pacific silver fir and madrona is high, while that of Western hemlock
is moderate. The danger of windthrow increases where dense stands have been thinned.
Other species (unless they are on shallow, wet soils less than 20 inches deep) have a low
windthrow hazard.
l Cottonwoods, maples, and willows have water-seeking roots. These can cause trouble in
sewer lines and infiltration fields. On the other hand, they thrive in high moisture conditions
that other trees would not.
l Thinning operations in pure or mixed stands of Grand fir, Pacific silver fir, Noble fir, Sitka
spruce, Western red cedar, Western hemlock, Pacific dogwood, and Red alder can cause ser-
ious disease problems. Disease can become established through damaged limbs, trunks,
roots, and freshly cut stumps. Diseased and weakened trees are also susceptible to insect
attack.
Maintenance Standards
Inspect flagged and/or fenced areas regularly to make sure flagging or fencing has not been
removed or damaged. If the flagging or fencing has been damaged or visibility reduced, it shall be
repaired or replaced immediately and visibility restored.
2019 Stormwater Management Manual for Western Washington
Volume II -Chapter 3 -Page 272
If tree roots have been exposed or injured, “prune” cleanly with an appropriate pruning saw or lop-
pers directly above the damaged roots and recover with native soils. Treatment of sap flowing trees
(fir, hemlock, pine, soft maples) is not advised as sap forms a natural healing barrier.
BMP C102: Buffer Zones
Purpose
Creation of an undisturbed area or strip of natural vegetation or an established suitable planting that
will provide a living filter to reduce soil erosion and stormwater runoff velocities.
Conditions of Use
Buffer zones are used along streams, wetlands and other bodies of water that need protection from
erosion and sedimentation. Contractors can use vegetative buffer zone BMPs to protect natural
swales and they can incorporate them into the natural landscaping of an area.
Do not use critical-areas buffer zones as sediment treatment areas. These areas shall remain com-
pletely undisturbed. The local permitting authority may expand the buffer widths temporarily to allow
the use of the expanded area for removal of sediment.
The types of buffer zones can change the level of protection required as shown below:
Designated Critical Area Buffers - buffers that protect Critical Areas, as defined by the Washington
State Growth Management Act, and are established and managed by the local permitting authority.
These should not be disturbed and must protected with sediment control BMPs to prevent impacts.
The local permitting authority may expand the buffer widths temporarily to allow the use of the expan-
ded area for removal of sediment.
Vegetative Buffer Zones - areas that may be identified in undisturbed vegetation areas or managed
vegetation areas that are outside any Designated Critical Area Buffer. They may be utilized to
provide an additional sediment control area and/or reduce runoff velocities. If being used for pre-
servation of natural vegetation, they should be arranged in clumps or strips. They can be used to pro-
tect natural swales and incorporated into the natural landscaping area.
Design and Installation Specifications
l Preserving natural vegetation or plantings in clumps, blocks, or strips is generally the easiest
and most successful method.
l Leave all unstable steep slopes in natural vegetation.
l Mark clearing limits and keep all equipment and construction debris out of the natural areas
and buffer zones. Steel construction fencing is the most effective method to protect sensitive
areas and buffers. Alternatively, wire-backed silt fence on steel posts is marginally effective.
Flagging alone is typically not effective.
l Keep all excavations outside the dripline of trees and shrubs.
l Do not push debris or extra soil into the buffer zone area because it will cause damage by
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burying and smothering vegetation.
l Vegetative buffer zones for streams, lakes or other waterways shall be established by the
local permitting authority or other state or federal permits or approvals.
Maintenance Standards
Inspect the area frequently to make sure flagging remains in place and the area remains undis-
turbed. Replace all damaged flagging immediately. Remove all materials located in the buffer area
that may impede the ability of the vegetation to act as a filter.
BMP C103: High-Visibility Fence
Purpose
High-visibility fencing is intended to:
l Restrict clearing to approved limits.
l Prevent disturbance of sensitive areas, their buffers, and other areas required to be left undis-
turbed.
l Limit construction traffic to designated construction entrances, exits, or internal roads.
l Protect areas where marking with survey tape may not provide adequate protection.
Conditions of Use
To establish clearing limits plastic, fabric, or metal fence may be used:
l At the boundary of sensitive areas, their buffers, and other areas required to be left uncleared.
l As necessary to control vehicle access to and on the site.
Design and Installation Specifications
High-visibility plastic fence shall be composed of a high-density polyethylene material and shall be at
least four feet in height. Posts for the fencing shall be steel or wood and placed every 6 feet on center
(maximum) or as needed to ensure rigidity. The fencing shall be fastened to the post every six 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 360 lbs/ft using the ASTM D4595 testing method.
If appropriate install fabric silt fence in accordance with BMP C233: Silt Fence to act as high-visibility
fence. Silt fence shall be at least 3 feet high and must be highly visible to meet the requirements of
this BMP.
Metal fences shall be designed and installed according to the manufacturer's specifications.
Metal fences shall be at least 3 feet high and must be highly visible.
Fences shall not be wired or stapled to trees.
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Maintenance Standards
If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and
visibility restored.
BMP C105: Stabilized Construction Access
Purpose
Stabilized construction accesses are established to reduce the amount of sediment transported onto
paved roads outside the project site by vehicles or equipment. This is done by constructing a sta-
bilized pad of quarry spalls at entrances and exits for project sites.
Conditions of Use
Construction accesses shall be stabilized wherever traffic will be entering or leaving a construction
site if paved roads or other paved areas are within 1,000 feet of the site.
For residential subdivision construction sites, provide a stabilized construction access for each res-
idence, rather than only at the main subdivision entrance. Stabilized surfaces shall be of sufficient
length/width to provide vehicle access/parking, based on lot size and configuration.
On large commercial, highway, and road projects, the designer should include enough extra mater-
ials in the contract to allow for additional stabilized accesses not shown in the initial Construction
SWPPP. It is difficult to determine exactly where access to these projects will take place; additional
materials will enable the contractor to install them where needed.
Design and Installation Specifications
See Figure II-3.1: Stabilized Construction Access for details. Note: the 100’ minimum length of the
access shall be reduced to the maximum practicable size when the size or configuration of the site
does not allow the full length (100’).
Construct stabilized construction accesses with a 12-inch thick pad of 4-inch to 8-inch quarry spalls,
a 4-inch course of asphalt treated base (ATB), or use existing pavement. Do not use crushed con-
crete, cement, or calcium chloride for construction access stabilization because these products raise
pH levels in stormwater and concrete discharge to waters of the State is prohibited.
A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up
into the rock pad. The geotextile shall meet the standards listed in Table II-3.2: Stabilized Con-
struction Access Geotextile Standards.
Geotextile Property Required Value
Grab Tensile Strength (ASTM D4751)200 psi min.
Table II-3.2: Stabilized Construction Access
Geotextile Standards
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Geotextile Property Required Value
Grab Tensile Elongation (ASTM D4632)30% max.
Mullen Burst Strength (ASTM D3786-80a)400 psi min.
AOS (ASTM D4751)20-45 (U.S. standard sieve size)
Table II-3.2: Stabilized Construction Access
Geotextile Standards (continued)
l Consider early installation of the first lift of asphalt in areas that will be paved; this can be used
as a stabilized access. Also consider the installation of excess concrete as a stabilized access.
During large concrete pours, excess concrete is often available for this purpose.
l Fencing (see BMP C103: High-Visibility Fence) shall be installed as necessary to restrict
traffic to the construction access.
l Whenever possible, the access shall be constructed on a firm, compacted subgrade. This can
substantially increase the effectiveness of the pad and reduce the need for maintenance.
l Construction accesses should avoid crossing existing sidewalks and back of walk drains if at
all possible. If a construction access must cross a sidewalk or back of walk drain, the full length
of the sidewalk and back of walk drain must be covered and protected from sediment leaving
the site.
Alternative Material Specification
WSDOT has raised safety concerns about the Quarry Spall rock specified above. WSDOT observes
that the 4-inch to 8-inch rock sizes can become trapped between Dually truck tires, and then
released off-site at highway speeds. WSDOT has chosen to use a modified specification for the rock
while continuously verifying that the Stabilized Construction Access remains effective. To remain
effective, the BMP must prevent sediment from migrating off site. To date, there has been no per-
formance testing to verify operation of this new specification. Jurisdictions may use the alternative
specification, but must perform increased off-site inspection if they use, or allow others to use, it.
Stabilized Construction Accesses may use material that meets the requirements of WSDOT's Stand-
ard Specifications for Road, Bridge, and Municipal Construction Section 9-03.9(1) (WSDOT, 2016)
for ballast except for the following special requirements.
The grading and quality requirements are listed in Table II-3.3: Stabilized Construction Access
Alternative Material Requirements.
Sieve Size Percent Passing
2½″99-100
Table II-3.3: Stabilized
Construction Access
Alternative Material
Requirements
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Sieve Size Percent Passing
2″65-100
¾″40-80
No. 4 5 max.
No. 100 0-2
% Fracture 75 min.
Table II-3.3: Stabilized
Construction Access
Alternative Material
Requirements
(continued)
l All percentages are by weight.
l The sand equivalent value and dust ratio requirements do not apply.
l The fracture requirement shall be at least one fractured face and will apply the combined
aggregate retained on the No. 4 sieve in accordance with FOP for AASHTO T 335.
Maintenance Standards
Quarry spalls shall be added if the pad is no longer in accordance with the specifications.
l If the access is not preventing sediment from being tracked onto pavement, then alternative
measures to keep the streets free of sediment shall be used. This may include replace-
ment/cleaning of the existing quarry spalls, street sweeping, an increase in the dimensions of
the access, or the installation of BMP C106: Wheel Wash.
l Any sediment that is tracked onto pavement shall be removed by shoveling or street sweep-
ing. The sediment collected by sweeping shall be removed or stabilized on site. The pavement
shall not be cleaned by washing down the street, except when high efficiency sweeping is inef-
fective and there is a threat to public safety. If it is necessary to wash the streets, the con-
struction of a small sump to contain the wash water shall be considered. The sediment would
then be washed into the sump where it can be controlled.
l Perform street sweeping by hand or with a high efficiency sweeper. Do not use a non-high effi-
ciency mechanical sweeper because this creates dust and throws soils into storm systems or
conveyance ditches.
l Any quarry spalls that are loosened from the pad, which end up on the roadway shall be
removed immediately.
l If vehicles are entering or exiting the site at points other than the construction access(es),
BMP C103: High-Visibility Fence shall be installed to control traffic.
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l Upon project completion and site stabilization, all construction accesses intended as per-
manent access for maintenance shall be permanently stabilized.
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Figure II-3.1: Stabilized Construction Access
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Approved as Functionally Equivalent
Ecology has approved products as able to meet the requirements of this BMP. The products did not
pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions
may choose not to accept these products, or may require additional testing prior to consideration for
local use. Products that Ecology has approved as functionally equivalent are available for review on
Ecology’s website at:
https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per-
mittee-guidance-resources/Emerging-stormwater-treatment-technologies
BMP C106: Wheel Wash
Purpose
Wheel washes reduce the amount of sediment transported onto paved roads by washing dirt from
the wheels of motor vehicles prior to the motor vehicles leaving the construction site.
Conditions of Use
l Use a wheel wash when BMP C105: Stabilized Construction Access is not preventing sed-
iment from being tracked off site.
l Wheel washing is generally an effective BMP when installed with careful attention to topo-
graphy. For example, a wheel wash can be detrimental if installed at the top of a slope abut-
ting a right-of-way where the water from the dripping truck can run unimpeded into the street.
l 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.
l Wheel wash wastewater is not stormwater. It is commonly called process water, and must be
discharged to a separate on-site treatment system that prevents discharge to waters of the
State, or to the sanitary sewer with local sewer district approval.
l Wheel washes may use closed-loop recirculation systems to conserve water use.
l Wheel wash wastewater shall not include wastewater from concrete washout areas.
l When practical, the wheel wash should be placed in sequence with BMP C105: Stabilized
Construction Access. Locate the wheel wash such that vehicles exiting the wheel wash will
enter directly onto BMP C105: Stabilized Construction Access. In order to achieve this, BMP
C105: Stabilized Construction Access may need to be extended beyond the standard install-
ation to meet the exit of the wheel wash.
Design and Installation Specifications
Suggested details are shown in Figure II-3.2: Wheel Wash. The Local Permitting Authority may
allow other designs. A minimum of 6 inches of asphalt treated base (ATB) over crushed base mater-
ial or 8 inches over a good subgrade is recommended to pave the wheel wash.
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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 sed-
iment. 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 may be used to promote coagulation and flocculation in a
closed-loop system. Polyacrylamide (PAM) 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 time. If PAM is
already being used for dust or erosion control and is being applied by a water truck, the same truck
can be used to change the wash water.
Maintenance Standards
The wheel wash should start out each day with fresh water.
The wheel 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 wheel wash water will need to be changed
more often.
Approved as Functionally Equivalent
Ecology has approved products as able to meet the requirements of this BMP. The products did not
pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions
may choose not to accept these products, or may require additional testing prior to consideration for
local use. Products that Ecology has approved as functionally equivalent are available for review on
Ecology’s website at:
https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per-
mittee-guidance-resources/Emerging-stormwater-treatment-technologies
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Figure II-3.2: Wheel Wash
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BMP C107: Construction Road / Parking Area
Stabilization
Purpose
Stabilizing roads, parking areas, and other on-site vehicle transportation routes immediately after
grading reduces erosion caused by construction traffic or stormwater runoff.
Conditions of Use
Roads and parking areas shall be stabilized wherever they are constructed, whether permanent or
temporary, for use by construction traffic.
BMP C103: High-Visibility Fence shall be installed, if necessary, to limit the access of vehicles to only
those roads and parking areas that are stabilized.
Design and Installation Specifications
l On areas that will receive asphalt as part of the project, install the first lift as soon as possible.
l A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course
shall be applied immediately after grading or utility installation. A 4-inch course of asphalt
treated base (ATB) may also be used, or the road/parking area may be paved. It may also be
possible to use cement or calcium chloride for soil stabilization. If cement or cement kiln dust is
used for roadbase stabilization, pH monitoring and BMP C252: Treating and Disposing of
High pH Water is necessary to evaluate and minimize the effects on stormwater. If the area
will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel
may also be used, but this is likely to require more maintenance. Whenever possible, con-
struction roads and parking areas shall be placed on a firm, compacted subgrade.
l Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to
drain. Drainage ditches shall be provided on each side of the roadway in the case of a
crowned section, or on one side in the case of a super-elevated section. Drainage ditches
shall be directed to a sediment control BMP.
l Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet-
flows into a heavily vegetated area with a well-developed topsoil. Landscaped areas are not
adequate. If this area has at least 50 feet of vegetation that water can flow through, then it is
generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap.
The 50 feet shall not include wetlands or their buffers. If runoff is allowed to sheetflow through
adjacent vegetated areas, it is vital to design the roadways and parking areas so that no con-
centrated runoff is created.
l Storm drain inlets shall be protected to prevent sediment-laden water entering the drainage
system (see BMP C220: Inlet Protection).
Maintenance Standards
Inspect stabilized areas regularly, especially after large storm events.
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Crushed rock, gravel base, etc., shall be added as required to maintain a stable driving surface and
to stabilize any areas that have eroded.
Following construction, these areas shall be restored to pre-construction condition or better to pre-
vent future erosion.
Perform street cleaning at the end of each day or more often if necessary.
BMP C120: Temporary and Permanent Seeding
Purpose
Seeding reduces erosion by stabilizing exposed soils. A well-established vegetative cover is one of
the most effective methods of reducing erosion.
Conditions of Use
Use seeding throughout the project on disturbed areas that have reached final grade or that will
remain unworked for more than 30 days.
The optimum seeding windows for western Washington are April 1 through June 30 and September
1 through October 1.
Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is established.
Between October 1 and March 30 seeding requires a cover of mulch or an erosion control blanket
until 75 percent grass cover is established.
Review all disturbed areas in late August to early September and complete all seeding by the end of
September. Otherwise, vegetation will not establish itself enough to provide more than average pro-
tection.
Mulch is required at all times for seeding because it protects seeds from heat, moisture loss, and
transport due to runoff. Mulch can be applied on top of the seed or simultaneously by hydroseeding.
See BMP C121: Mulching for specifications.
Seed and mulch all disturbed areas not otherwise vegetated at final site stabilization. Final sta-
bilization 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, or geotextiles) which will prevent erosion. See BMP T5.13: Post-Construction Soil
Quality and Depth.
Design and Installation Specifications
General
l Install channels intended for vegetation before starting major earthwork and hydroseed with a
Bonded Fiber Matrix. For vegetated channels that will have high flows, install erosion control
blankets over the top of hydroseed. Before allowing water to flow in vegetated channels,
establish 75 percent vegetation cover. If vegetated channels cannot be established by seed
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before water flow; install sod in the channel bottom — over top of hydromulch and erosion con-
trol blankets.
l Confirm the installation of all required surface water control measures to prevent seed from
washing away.
l Hydroseed applications shall include a minimum of 1,500 pounds per acre of mulch with 3 per-
cent tackifier. See BMP C121: Mulching for specifications.
l Areas that will have seeding only and not landscaping may need compost or meal-based
mulch included in the hydroseed in order to establish vegetation. Re-install native topsoil on
the disturbed soil surface before application. See BMP T5.13: Post-Construction Soil Quality
and Depth.
l 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. To overcome this, consider increasing seed quantities by up to 50 percent.
l Enhance vegetation establishment by dividing the hydromulch operation into two phases:
o Phase 1- Install all seed and fertilizer with 25-30 percent mulch and tackifier onto soil in
the first lift.
o Phase 2- Install the rest of the mulch and tackifier over the first lift.
Or, enhance vegetation by:
o Installing the mulch, seed, fertilizer, and tackifier in one lift.
o Spread or blow straw over the top of the hydromulch at a rate of 800-1000 pounds per
acre.
o Hold straw in place with a standard tackifier.
Both of these approaches will increase cost moderately but will greatly improve and enhance
vegetative establishment. The increased cost may be offset by the reduced need for:
o Irrigation.
o Reapplication of mulch.
o Repair of failed slope surfaces.
This technique works with standard hydromulch (1,500 pounds per acre minimum) and Bon-
ded Fiber Matrix/ Mechanically Bonded Fiber Matrix (BFM/MBFMs) (3,000 pounds per acre
minimum).
l Seed may be installed by hand if:
o Temporary and covered by straw, mulch, or topsoil.
o Permanent in small areas (usually less than 1 acre) and covered with mulch, topsoil, or
erosion blankets.
l The seed mixes listed in Table II-3.4: Temporary and Permanent Seed Mixes include
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recommended mixes for both temporary and permanent seeding.
l Apply these mixes, with the exception of the wet area seed mix, at a rate of 120 pounds per
acre. This rate can be reduced if soil amendments or slow-release fertilizers are used. Apply
the wet area seed mix at a rate of 60 pounds per acre.
l Consult the local suppliers or the local conservation district for their recommendations. 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,
depending on the soil type and hydrology of the area.
Common Name Latin Name % Weight % Purity % Germination
Temporary Erosion Control Seed Mix
A standard mix for areas requiring a temporary vegetative cover.
Chewings or
annual blue grass
Festuca rubra var.
commutata or Poa
anna
40 98 90
Perennial rye Lolium perenne 50 98 90
Redtop or colonial
bentgrass
Agrostis alba or
Agrostis tenuis 5 92 85
White dutch clover Trifolium repens 5 98 90
Landscaping Seed Mix
A recommended mix for landscaping seed.
Perennial rye blend Lolium perenne 70 98 90
Chewings and red
fescue blend
Festuca rubra var.
commutata or Fes-
tuca rubra
30 98 90
Low-Growing Turf Seed Mix
A turf seed mix for dry situations where there is no need for watering. This mix requires very little main-
tenance.
Dwarf tall fescue
(several varieties)
Festuca arundin-
acea var. 45 98 90
Dwarf perennial
rye (Barclay)
Lolium perenne
var. barclay 30 98 90
Red fescue Festuca rubra 20 98 90
Colonial bentgrass Agrostis tenuis 5 98 90
Bioswale Seed Mix
A seed mix for bioswales and other intermittently wet areas.
Tall or meadow fes-Festuca arundin-75-80 98 90
Table II-3.4: Temporary and Permanent Seed Mixes
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Common Name Latin Name % Weight % Purity % Germination
cue acea or Festuca
elatior
Seaside/Creeping
bentgrass Agrostis palustris 10-15 92 85
Redtop bentgrass Agrostis alba or
Agrostis gigantea 5-10 90 80
Wet Area Seed Mix
A low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wet-
lands. Consult Hydraulic Permit Authority (HPA) for seed mixes if applicable.
Tall or meadow fes-
cue
Festuca arundin-
acea or Festuca
elatior
60-70 98 90
Seaside/Creeping
bentgrass Agrostis palustris 10-15 98 85
Meadow foxtail Alepocurus praten-
sis 10-15 90 80
Alsike clover Trifolium hybridum 1-6 98 90
Redtop bentgrass Agrostis alba 1-6 92 85
Meadow Seed Mix
A recommended meadow seed mix for infrequently maintained areas or non-maintained areas where col-
onization by native plants is desirable. Likely applications include rural road and utility right-of-way. Seed-
ing should take place in September or very early October in order to obtain adequate establishment prior to
the winter months. Consider the appropriateness of clover, a fairly invasive species, in the mix. Amending
the soil can reduce the need for clover.
Redtop or Oregon
bentgrass
Agrostis alba or
Agrostis ore-
gonensis
20 92 85
Red fescue Festuca rubra 70 98 90
White dutch clover Trifolium repens 10 98 90
Table II-3.4: Temporary and Permanent Seed Mixes (continued)
Roughening and Rototilling
l The seedbed should be firm and rough. Roughen all soil no matter what the slope. Track walk
slopes before seeding if engineering purposes require compaction. Backblading or smoothing
of slopes greater than 4H:1V is not allowed if they are to be seeded.
l Restoration-based landscape practices require deeper incorporation than that provided by a
simple single-pass rototilling treatment. Wherever practical, initially rip the subgrade to
improve long-term permeability, infiltration, and water inflow qualities. At a minimum,
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permanent areas shall use soil amendments to achieve organic matter and permeability per-
formance defined in engineered soil/landscape systems. For systems that are deeper than 8
inches complete the rototilling process in multiple lifts, or prepare the engineered soil system
per specifications and place to achieve the specified depth.
Fertilizers
l Conducting soil tests to determine the exact type and quantity of fertilizer is recommended.
This will prevent the over-application of fertilizer.
l Organic matter is the most appropriate form of fertilizer because it provides nutrients (includ-
ing nitrogen, phosphorus, and potassium) in the least water-soluble form.
l In general, use 10-4-6 N-P-K (nitrogen-phosphorus-potassium) fertilizer at a rate of 90
pounds per acre. Always use slow-release fertilizers because they are more efficient and
have fewer environmental impacts. Do not add fertilizer to the hydromulch machine, or agit-
ate, more than 20 minutes before use. Too much agitation destroys the slow-release coating.
l There are numerous products available 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 provides a good source of long-term, slow-release, available
nitrogen.
Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix
l On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix
(MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre
with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during
application. Numerous products are available commercially. Most products require 24-36
hours to cure before rainfall and cannot be installed on wet or saturated soils. Generally,
products come in 40-50 pound bags and include all necessary ingredients except for seed and
fertilizer.
l Install products per manufacturer's instructions.
l BFMs and MBFMs provide good alternatives to blankets in most areas requiring vegetation
establishment. Advantages over blankets include:
o BFM and MBFMs do not require surface preparation.
o Helicopters can assist in installing BFM and MBFMs in remote areas.
o On slopes steeper than 2.5H:1V, blanket installers may require ropes and harnesses
for safety.
o Installing BFM and MBFMs can save at least $1,000 per acre compared to blankets.
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Maintenance Standards
Reseed any seeded areas that fail to establish at least 75 percent cover (100 percent cover for areas
that receive sheet or concentrated flows). If reseeding is ineffective, use an alternate method such
as sodding, mulching, nets, or blankets.
l Reseed and protect by mulch any areas that experience erosion after achieving adequate
cover. Reseed and protect by mulch any eroded area.
l Supply seeded areas with adequate moisture, but do not water to the extent that it causes run-
off.
Approved as Functionally Equivalent
Ecology has approved products as able to meet the requirements of this BMP. The products did not
pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions
may choose not to accept these products, or may require additional testing prior to consideration for
local use. Products that Ecology has approved as functionally equivalent are available for review on
Ecology’s website at:
https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per-
mittee-guidance-resources/Emerging-stormwater-treatment-technologies
BMP C121: Mulching
Purpose
Mulching soils provides immediate temporary protection from erosion. Mulch also enhances plant
establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and moderating
soil temperatures. There are a variety of mulches that can be used. This section discusses only the
most common types of mulch.
Conditions of Use
As a temporary cover measure, mulch should be used:
l For less than 30 days on disturbed areas that require cover.
l At all times for seeded areas, especially during the wet season and during the hot summer
months.
l During 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.
For seeded areas, mulch may be made up of 100 percent:
l cottonseed meal;
l fibers made of wood, recycled cellulose, hemp, or kenaf;
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BMP C123: Plastic Covering
Purpose
Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas.
Conditions of Use
Plastic covering may be used on disturbed areas that require cover measures for less than 30 days,
except as stated below.
l Plastic is particularly useful for protecting cut and fill slopes and stockpiles. However, the rel-
atively rapid breakdown of most polyethylene sheeting makes it unsuitable for applications
greater than six months.
l Due to rapid runoff caused by plastic covering, do not use this method upslope of areas that
might be adversely impacted by concentrated runoff. Such areas include steep and/or
unstable slopes.
l Plastic sheeting may result in increased runoff volumes and velocities, requiring additional on-
site measures to counteract the increases. Creating a trough with wattles or other material
can convey clean water away from these areas.
l To prevent undercutting, trench and backfill rolled plastic covering products.
l Although the plastic material is inexpensive to purchase, the cost of installation, maintenance,
removal, and disposal add to the total costs of this BMP.
l Whenever plastic is used to protect slopes, install water collection measures at the base of the
slope. These measures include plastic-covered berms, channels, and pipes used to convey
clean rainwater away from bare soil and disturbed areas. Do not mix clean runoff from a
plastic covered slope with dirty runoff from a project.
l Other uses for plastic include:
o Temporary ditch liner.
o Pond liner in temporary sediment pond.
o Liner for bermed temporary fuel storage area if plastic is not reactive to the type of fuel
being stored.
o Emergency slope protection during heavy rains.
o Temporary drainpipe (“elephant trunk”) used to direct water.
Design and Installation Specifications
l Plastic slope cover must be installed as follows:
1. Run plastic up and down the slope, not across the slope.
2. Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet.
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3. Provide a minimum of 8-inch overlap at the seams.
4. On long or wide slopes, or slopes subject to wind, tape all seams.
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 underneath.
6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and tie them
together with twine to hold them in place.
7. Inspect plastic for rips, tears, and open seams regularly and repair immediately. This
prevents high velocity runoff from contacting bare soil, which causes extreme erosion.
8. Sandbags may be lowered into place tied to ropes. However, all sandbags must be
staked in place.
l Plastic sheeting shall have a minimum thickness of 0.06 millimeters.
l 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 slope in order to reduce the velocity of runoff.
Maintenance Standards
l Torn sheets must be replaced and open seams repaired.
l Completely remove and replace the plastic if it begins to deteriorate due to ultraviolet radi-
ation.
l Completely remove plastic when no longer needed.
l Dispose of old tires used to weight down plastic sheeting appropriately.
Approved as Functionally Equivalent
Ecology has approved products as able to meet the requirements of this BMP. The products did not
pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions
may choose not to accept these products, or may require additional testing prior to consideration for
local use. Products that Ecology has approved as functionally equivalent are available for review on
Ecology’s website at:
https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per-
mittee-guidance-resources/Emerging-stormwater-treatment-technologies
BMP C124: Sodding
Purpose
The purpose of sodding is to establish turf for immediate erosion protection and to stabilize drainage
paths where concentrated overland flow will occur.
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BMP C140: Dust Control
Purpose
Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways, drainage
ways, and surface waters.
Conditions of Use
Use dust control in areas (including roadways) subject to surface and air movement of dust where
on-site or off-site impacts to roadways, drainage ways, or surface waters are likely.
Design and Installation Specifications
l Vegetate or mulch areas that will not receive vehicle traffic. In areas where planting, mulching,
or paving is impractical, apply gravel or landscaping rock.
l Limit dust generation by clearing only those areas where immediate activity will take place,
leaving the remaining area(s) in the original condition. Maintain the original ground cover as
long as practical.
l Construct natural or artificial windbreaks or windscreens. These may be designed as enclos-
ures for small dust sources.
l Sprinkle the site with water until the surface is wet. Repeat as needed. To prevent carryout of
mud onto the street, refer to BMP C105: Stabilized Construction Access and BMP C106:
Wheel Wash.
l Irrigation water can be used for dust control. Irrigation systems should be installed as a first
step on sites where dust control is a concern.
l Spray exposed soil areas with a dust palliative, following the manufacturer’s instructions and
cautions regarding handling and application. Used oil is prohibited from use as a dust sup-
pressant. Local governments may approve other dust palliatives such as calcium chloride or
PAM.
l PAM (BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection) added to water at a rate
of 0.5 pounds per 1,000 gallons of water per acre and applied from a water truck is more effect-
ive than water alone. This is due to increased infiltration of water into the soil and reduced
evaporation. In addition, small soil particles are bonded together and are not as easily trans-
ported by wind. Adding PAM may reduce the quantity of water needed for dust control. Note
that the application rate specified here applies to this BMP, and is not the same application
rate that is specified in BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection, but the
downstream protections still apply.
Refer to BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection for conditions of use.
PAM shall not be directly applied to water or allowed to enter a water body.
l Contact your local Air Pollution Control Authority for guidance and training on other dust con-
trol measures. Compliance with the local Air Pollution Control Authority constitutes
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compliance with this BMP.
l Use vacuum street sweepers.
l Remove mud and other dirt promptly so it does not dry and then turn into dust.
l Techniques that can be used for unpaved roads and lots include:
o Lower speed limits. High vehicle speed increases the amount of dust stirred up from
unpaved roads and lots.
o Upgrade the road surface strength by improving particle size, shape, and mineral types
that make up the surface and base materials.
o Add surface gravel to reduce the source of dust emission. Limit the amount of fine
particles (those smaller than .075 mm) to 10 to 20 percent.
o Use geotextile fabrics to increase the strength of new roads or roads undergoing recon-
struction.
o Encourage the use of alternate, paved routes, if available.
o Apply chemical dust suppressants using the admix method, blending the product with
the top few inches of surface material. Suppressants may also be applied as surface
treatments.
o Limit dust-causing work on windy days.
o Pave unpaved permanent roads and other trafficked areas.
Maintenance Standards
Respray area as necessary to keep dust to a minimum.
BMP C150: Materials on Hand
Purpose
Keep quantities of erosion prevention and sediment control materials on the project site at all times
to be used for regular maintenance and emergency situations such as unexpected heavy rains. Hav-
ing these materials on-site reduces the time needed to replace existing or implement new BMPs
when inspections indicate that existing BMPs are not meeting the Construction SWPPP require-
ments. In addition, contractors can save money by buying some materials in bulk and storing them at
their office or yard.
Conditions of Use
l 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
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pipe, sandbags, geotextile fabric and steel “T” posts.
l Materials should be stockpiled and readily available before any site clearing, grubbing, or
earthwork begins. A large contractor or project proponent could keep a stockpile of materials
that are available for use on several projects.
l 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 Installation Specifications
Depending on project type, size, complexity, and length, materials and quantities will vary. A good
minimum list of items that will cover numerous situations includes:
l Clear Plastic, 6 mil
l Drainpipe, 6 or 8 inch diameter
l Sandbags, filled
l Straw Bales for mulching
l Quarry Spalls
l Washed Gravel
l Geotextile Fabric
l Catch Basin Inserts
l Steel "T" Posts
l Silt fence material
l Straw Wattles
Maintenance Standards
l All materials with the exception of the quarry spalls, steel “T” posts, and gravel should be kept
covered and out of both sun and rain.
l Re-stock materials as needed.
BMP C151: Concrete Handling
Purpose
Concrete work can generate process water and slurry that contain fine particles and high pH, both of
which can violate water quality standards in the receiving water. Concrete spillage or concrete dis-
charge to waters of the State is prohibited. Use this BMP to minimize and eliminate concrete, con-
crete process water, and concrete slurry from entering waters of the State.
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Conditions of Use
Any time concrete is used, utilize these management practices. Concrete construction project com-
ponents include, but are not limited to:
l Curbs
l Sidewalks
l Roads
l Bridges
l Foundations
l Floors
l Runways
Disposal options for concrete, in order of preference are:
1. Off-site disposal
2. Concrete wash-out areas (see BMP C154: Concrete Washout Area)
3. De minimus washout to formed areas awaiting concrete
Design and Installation Specifications
l Wash concrete truck drums at an approved off-site location or in designated concrete
washout areas only. Do not wash out concrete trucks onto the ground (including formed areas
awaiting concrete), or into storm drains, open ditches, streets, or streams. Refer to BMP
C154: Concrete Washout Area for information on concrete washout areas.
o Return unused concrete remaining in the truck and pump to the originating batch plant
for recycling. Do not dump excess concrete on site, except in designated concrete
washout areas as allowed in BMP C154: Concrete Washout Area.
l Wash small concrete handling equipment (e.g. hand tools, screeds, shovels, rakes, floats,
trowels, and wheelbarrows) into designated concrete washout areas or into formed areas
awaiting concrete pour.
l At no time shall concrete be washed off into the footprint of an area where an infiltration fea-
ture will be installed.
l Wash equipment difficult to move, such as concrete paving machines, in areas that do not dir-
ectly drain to natural or constructed stormwater conveyance or potential infiltration areas.
l Do not allow washwater from areas, such as concrete aggregate driveways, to drain directly
(without detention or treatment) to natural or constructed stormwater conveyances.
l Contain washwater and leftover product in a lined container when no designated concrete
washout areas (or formed areas, allowed as described above) are available. Dispose of con-
tained concrete and concrete washwater (process water) properly.
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l Always use forms or solid barriers for concrete pours, such as pilings, within 15-feet of surface
waters.
l Refer to BMP C252: Treating and Disposing of High pH Water for pH adjustment require-
ments.
l Refer to the Construction Stormwater General Permit (CSWGP) for pH monitoring require-
ments if the project involves one of the following activities:
o Significant concrete work (as defined in the CSWGP).
o The use of soils amended with (but not limited to) Portland cement-treated base,
cement kiln dust or fly ash.
o Discharging stormwater to segments of water bodies on the 303(d) list (Category 5) for
high pH.
Maintenance Standards
Check containers for holes in the liner daily during concrete pours and repair the same day.
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. Concrete spillage or concrete discharge to waters of the State is prohibited. Use this BMP to
minimize and eliminate process water and slurry created through sawcutting or surfacing from enter-
ing waters of the State.
Conditions of Use
Utilize these management practices anytime sawcutting or surfacing operations take place. Saw-
cutting and surfacing operations include, but are not limited to:
l Sawing
l Coring
l Grinding
l Roughening
l Hydro-demolition
l Bridge and road surfacing
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Design and Installation Specifications
l Vacuum slurry and cuttings during cutting and surfacing operations.
l Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight.
l Slurry and cuttings shall not drain to any natural or constructed drainage conveyance includ-
ing stormwater systems. This may require temporarily blocking catch basins.
l Dispose of collected slurry and cuttings in a manner that does not violate ground water or sur-
face water quality standards.
l Do not allow process water generated during hydro-demolition, surface roughening or similar
operations to drain to any natural or constructed drainage conveyance including stormwater
systems. Dispose of process water in a manner that does not violate ground water or surface
water quality standards.
l Handle and dispose of cleaning waste material and demolition debris in a manner that does
not cause contamination of water. Dispose of sweeping material from a pick-up sweeper at an
appropriate disposal site.
Maintenance Standards
Continually monitor operations to determine whether slurry, cuttings, or process water could enter
waters of the state. If inspections show that a violation of water quality standards could occur, stop
operations and immediately implement preventive measures such as berms, barriers, secondary
containment, and/or vacuum trucks.
BMP C153: Material Delivery, Storage, and
Containment
Purpose
Prevent, reduce, or eliminate the discharge of pollutants to the stormwater system or watercourses
from material delivery and storage. Minimize the storage of hazardous materials on-site, store mater-
ials in a designated area, and install secondary containment.
Conditions of Use
Use at construction sites with delivery and storage of the following materials:
l Petroleum products such as fuel, oil and grease
l Soil stabilizers and binders (e.g., Polyacrylamide)
l Fertilizers, pesticides and herbicides
l Detergents
l Asphalt and concrete compounds
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l Hazardous chemicals such as acids, lime, adhesives, paints, solvents, and curing compounds
l Any other material that may be detrimental if released to the environment
Design and Installation Specifications
l The temporary storage area should be located away from vehicular traffic, near the con-
struction entrance(s), and away from waterways or storm drains.
l Safety Data Sheets (SDS) should be supplied for all materials stored. Chemicals should be
kept in their original labeled containers.
l Hazardous material storage on-site should be minimized.
l Hazardous materials should be handled as infrequently as possible.
l During the wet weather season (Oct 1 – April 30), consider storing materials in a covered
area.
l Materials should be stored in secondary containments, such as an earthen dike, horse trough,
or even a children’s wading pool for non-reactive materials such as detergents, oil, grease,
and paints. Small amounts of material may be secondarily contained in “bus boy” trays or con-
crete mixing trays.
l Do not store chemicals, drums, or bagged materials directly on the ground. Place these items
on a pallet and, when possible, within secondary containment.
l If drums must be kept uncovered, store them at a slight angle to reduce ponding of rainwater
on the lids to reduce corrosion. Domed plastic covers are inexpensive and snap to the top of
drums, preventing water from collecting.
l Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or 302 shall be
stored in approved containers and drums and shall not be overfilled. Containers and drums
shall be stored in temporary secondary containment facilities.
l Temporary secondary containment facilities shall provide for a spill containment volume able
to contain 10% of the total enclosed container volume of all containers, or 110% of the capa-
city of the largest container within its boundary, whichever is greater.
l Secondary containment facilities shall be impervious to the materials stored therein for a min-
imum contact time of 72 hours.
l Sufficient separation should be provided between stored containers to allow for spill cleanup
and emergency response access.
l During the wet weather season (Oct 1 – April 30), each secondary containment facility shall
be covered during non-working days, prior to and during rain events.
l Keep material storage areas clean, organized and equipped with an ample supply of appro-
priate spill clean-up material (spill kit).
l The spill kit should include, at a minimum:
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o 1-Water Resistant Nylon Bag
o 3-Oil Absorbent Socks 3”x 4’
o 2-Oil Absorbent Socks 3”x 10’
o 12-Oil Absorbent Pads 17”x19”
o 1-Pair Splash Resistant Goggles
o 3-Pair Nitrile Gloves
o 10-Disposable Bags with Ties
o Instructions
Maintenance Standards
l Secondary containment facilities shall be maintained free of accumulated rainwater and spills.
In the event of spills or leaks, accumulated rainwater and spills shall be collected and placed
into drums. These liquids shall be handled as hazardous waste unless testing determines
them to be non-hazardous.
l Re-stock spill kit materials as needed.
BMP C154: Concrete Washout Area
Purpose
Prevent or reduce the discharge of pollutants from concrete waste to stormwater by conducting
washout off-site, or performing on-site washout in a designated area.
Conditions of Use
Concrete washout areas are implemented on construction projects where:
l Concrete is used as a construction material
l It is not possible to dispose of all concrete wastewater and washout off-site (ready mix plant,
etc.).
l Concrete truck drums are washed on-site.
Note that auxiliary concrete truck components (e.g. chutes and hoses) and small concrete
handling equipment (e.g. hand tools, screeds, shovels, rakes, floats, trowels, and wheel-
barrows) may be washed into formed areas awaiting concrete pour.
At no time shall concrete be washed off into the footprint of an area where an infiltration feature will
be installed.
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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
responsible for ensuring compliance with all local, state, and federal erosion and sediment control
and water quality requirements. Construction sites one acre or larger that discharge to waters of the
State must designate a Certified Erosion and Sediment Control Lead (CESCL) as the responsible
representative.
Conditions of Use
A CESCL shall be made available on projects one acre or larger that discharge stormwater to sur-
face waters of the state. Sites less than one acre may have a person without CESCL certification
conduct inspections.
The CESCL shall:
l Have a current certificate proving attendance in an erosion and sediment control training
course that meets the minimum ESC training and certification requirements established by
Ecology.
Ecology has provided the minimum requirements for CESCL course training, as well as a list
of ESC training and certification providers at:
https://ecology.wa.gov/Regulations-Permits/Permits-certifications/Certified-erosion-sed-
iment-control
OR
l Be a Certified Professional in Erosion and Sediment Control (CPESC). For additional inform-
ation go to:
http://www.envirocertintl.org/cpesc/
Specifications
l CESCL certification shall remain valid for three years.
l The CESCL shall have authority to act on behalf of the contractor or project proponent and
shall be available, or on-call, 24 hours per day throughout the period of construction.
l The Construction SWPPP shall include the name, telephone number, fax number, and
address of the designated CESCL. See II-2 Construction Stormwater Pollution Prevention
Plans (Construction SWPPPs).
l A CESCL may provide inspection and compliance services for multiple construction projects
in the same geographic region, but must be on site whenever earthwork activities are
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occurring that could generate release of turbid water.
l Duties and responsibilities of the CESCL shall include, but are not limited to the following:
o Maintaining a permit file on site at all times which includes the Construction SWPPP
and any associated permits and plans.
o Directing BMP installation, inspection, maintenance, modification, and removal.
o Updating all project drawings and the Construction SWPPP with changes made.
o Completing any sampling requirements including reporting results using electronic Dis-
charge Monitoring Reports (WebDMR).
o Facilitate, participate in, and take corrective actions resulting from inspections per-
formed by outside agencies or the owner.
o Keeping daily logs, and inspection reports. Inspection reports should include:
n Inspection date/time.
n Weather information; general conditions during inspection and approximate
amount of precipitation since the last inspection.
n Visual monitoring results, including a description of discharged stormwater. The
presence of suspended sediment, turbid water, discoloration, and oil sheen shall
be noted, as applicable.
n Any water quality monitoring performed during inspection.
n General comments and notes, including a brief description of any BMP repairs,
maintenance or installations made as a result of the inspection.
n 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.
4. Locations of where additional or different BMPs are required.
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.
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Conditions of Use
The construction sequence schedule is an orderly listing of all major land-disturbing 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 work 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
construction. The removal of ground cover leaves a site vulnerable to erosion. Construction sequen-
cing that limits land clearing, provides timely installation of erosion and sedimentation controls, and
restores protective cover quickly can significantly reduce the erosion potential of a site.
Design Considerations
l Minimize construction during rainy periods.
l Schedule projects to disturb only small portions of the site at any one time. Complete grading
as soon as possible. Immediately stabilize the disturbed portion before grading the next por-
tion. Practice staged seeding in order to revegetate cut and fill slopes as the work progresses.
II-3.3 Construction Runoff BMPs
BMP C200: Interceptor Dike and Swale
Purpose
Provide a dike of compacted soil or a swale at the top or base of a disturbed slope or along the peri-
meter of a disturbed construction area to convey stormwater. Use the dike and/or swale to 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 con-
struction site.
Conditions of Use
Use an interceptor dike or swale where runoff from an exposed site or disturbed slope must be con-
veyed to an erosion control BMP which can safely convey the stormwater.
l Locate upslope of a construction site to prevent runoff from entering the disturbed area.
l When placed horizontally across a disturbed slope, it reduces the amount and velocity of run-
off flowing down the slope.
l Locate downslope to collect runoff from a disturbed area and direct it to a sediment BMP (e.g.
BMP C240: Sediment Trap or BMP C241: Sediment Pond (Temporary)).
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thickness is 2 feet.
o For outlets at the base of steep slope pipes (pipe slope greater than 10 percent), use an
engineered energy dissipator.
o Filter fabric or erosion control blankets should always be used under riprap to prevent
scour and channel erosion. See BMP C122: Nets and Blankets.
l Bank stabilization, bioengineering, and habitat features may be required for disturbed areas.
This work may require a Hydraulic Project Approval (HPA) from the Washington State Depart-
ment of Fish and Wildlife. See I-2.11 Hydraulic Project Approvals.
Maintenance Standards
l Inspect and repair as needed.
l Add rock as needed to maintain the intended function.
l Clean energy dissipator if sediment builds up.
BMP C220: Inlet Protection
Purpose
Inlet protection prevents coarse sediment from entering drainage systems prior to permanent sta-
bilization of the disturbed area.
Conditions of Use
Use inlet protection at inlets that are operational before permanent stabilization of the disturbed
areas that contribute runoff to the inlet. Provide protection for all storm drain inlets downslope and
within 500 feet of a disturbed or construction area, unless those inlets are preceded by a sediment
trapping BMP.
Also consider inlet protection for lawn and yard drains on new home construction. These small and
numerous drains coupled with lack of gutters can add significant amounts of sediment into the roof
drain system. If possible, delay installing lawn and yard drains until just before landscaping, or cap
these drains to prevent sediment from entering the system until completion of landscaping. Provide
18-inches of sod around each finished lawn and yard drain.
Table II-3.10: Storm Drain Inlet Protection lists several options for inlet protection. All of the methods
for inlet protection tend to plug and require a high frequency of maintenance. Limit contributing drain-
age areas for an individual inlet to one acre or less. If possible, provide emergency overflows with
additional end-of-pipe treatment where stormwater ponding would cause a hazard.
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Type of Inlet Pro-
tection
Emergency
Overflow
Applicable for
Paved/ Earthen Sur-
faces
Conditions of Use
Drop Inlet Protection
Excavated drop
inlet protection
Yes, temporary
flooding may
occur
Earthen
Applicable for heavy flows. Easy
to maintain. Large area requirement:
30'x30'/acre
Block and gravel
drop inlet pro-
tection
Yes Paved or Earthen Applicable for heavy concentrated flows.
Will not pond.
Gravel and wire
drop inlet pro-
tection
No Paved or Earthen Applicable for heavy concentrated flows.
Will pond. Can withstand traffic.
Catch basin filters Yes Paved or Earthen Frequent maintenance required.
Curb Inlet Protection
Curb inlet pro-
tection with
wooden weir
Small capacity
overflow Paved Used for sturdy, more compact install-
ation.
Block and gravel
curb inlet pro-
tection
Yes Paved Sturdy, but limited filtration.
Culvert Inlet Protection
Culvert inlet sed-
iment trap N/A N/A 18 month expected life.
Table II-3.10: Storm Drain Inlet Protection
Design and Installation Specifications
Excavated Drop Inlet Protection
Excavated drop inlet protection consists of an excavated impoundment around the storm drain inlet.
Sediment settles out of the stormwater prior to entering the storm drain. Design and installation spe-
cifications for excavated drop inlet protection include:
l Provide a depth of 1-2 ft as measured from the crest of the inlet structure.
l Slope sides of excavation should be no steeper than 2H:1V.
l Minimum volume of excavation is 35 cubic yards.
l Shape the excavation to fit the site, with the longest dimension oriented toward the longest
inflow area.
l Install provisions for draining to prevent standing water.
l Clear the area of all debris.
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l Grade the approach to the inlet uniformly.
l Drill weep holes into the side of the inlet.
l Protect weep holes with screen wire and washed aggregate.
l Seal weep holes when removing structure and stabilizing area.
l Build a temporary dike, if necessary, to the down slope side of the structure to prevent bypass
flow.
Block and Gravel Filter
A block and gravel filter is a barrier formed around the inlet with standard concrete blocks and gravel.
See Figure II-3.17: Block and Gravel Filter. Design and installation specifications for block gravel fil-
ters include:
l Provide a height of 1 to 2 feet above the inlet.
l Recess the first row of blocks 2-inches into the ground for stability.
l Support subsequent courses by placing a pressure treated wood 2x4 through the block open-
ing.
l Do not use mortar.
l Lay some blocks in the bottom row on their side to allow for dewatering the pool.
l Place hardware cloth or comparable wire mesh with ½-inch openings over all block openings.
l Place gravel to just below the top of blocks on slopes of 2H:1V or flatter.
l An alternative design is a gravel berm surrounding the inlet, as follows:
o Provide a slope of 3H:1V on the upstream side of the berm.
o Provide a slope of 2H:1V on the downstream side of the berm.
o Provide a 1-foot wide level stone area between the gravel berm and the inlet.
o Use stones 3 inches in diameter or larger on the upstream slope of the berm.
o Use gravel ½- to ¾-inch at a minimum thickness of 1-foot on the downstream slope of
the berm.
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Figure II-3.17: Block and Gravel Filter
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Gravel and Wire Mesh Filter
Gravel and wire mesh filters are gravel barriers placed over the top of the inlet. This method does not
provide an overflow. Design and installation specifications for gravel and wire mesh filters include:
l Use a hardware cloth or comparable wire mesh with ½-inch openings.
o Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot bey-
ond each side of the inlet structure.
o Overlap the strips if more than one strip of mesh is necessary.
l Place coarse aggregate over the wire mesh.
o Provide at least a 12-inch depth of aggregate over the entire inlet opening and extend at
least 18-inches on all sides.
Catch Basin Filters
Catch basin filters are designed by manufacturers for construction sites. The limited sediment stor-
age capacity increases the amount of inspection and maintenance required, which may be daily for
heavy sediment loads. To reduce maintenance requirements, combine a catch basin 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. Design and install-
ation specifications for catch basin filters include:
l Provides 5 cubic feet of storage.
l Requires dewatering provisions.
l Provides a high-flow bypass that will not clog under normal use at a construction site.
l Insert the catch basin filter in the catch basin just below the grating.
Curb Inlet Protection with Wooden Weir
Curb inlet protection with wooden weir is an option that consists of a barrier formed around a curb
inlet with a wooden frame and gravel. Design and installation specifications for curb inlet protection
with wooden weirs include:
l Use wire mesh with ½-inch openings.
l Use extra strength filter cloth.
l Construct a frame.
l Attach the wire and filter fabric to the frame.
l Pile coarse washed aggregate against the wire and fabric.
l Place weight on the frame anchors.
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Block and Gravel Curb Inlet Protection
Block and gravel curb inlet protection is a barrier formed around a curb inlet with concrete blocks and
gravel. See Figure II-3.18: Block and Gravel Curb Inlet Protection. Design and installation spe-
cifications for block and gravel curb inlet protection include:
l Use wire mesh with ½-inch openings.
l Place two concrete blocks on their sides abutting the curb at either side of the inlet opening.
These are spacer blocks.
l Place a 2x4 stud through the outer holes of each spacer block to align the front blocks.
l Place blocks on their sides across the front of the inlet and abutting the spacer blocks.
l Place wire mesh over the outside vertical face.
l Pile coarse aggregate against the wire to the top of the barrier.
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Figure II-3.18: Block and Gravel Curb Inlet Protection
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Curb and Gutter Sediment Barrier
Curb and gutter sediment barrier is a sandbag or rock berm (riprap and aggregate) 3 feet high and 3
feet wide in a horseshoe shape. See Figure II-3.19: Curb and Gutter Barrier. Design and installation
specifications for curb and gutter sediment barrier include:
l Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high
and 3 feet wide, at least 2 feet from the inlet.
l Construct a horseshoe shaped sedimentation trap on the upstream side of the berm. Size the
trap to sediment trap standards for protecting a culvert inlet.
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Figure II-3.19: Curb and Gutter Barrier
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Maintenance Standards
l Inspect all forms of inlet protection frequently, especially after storm events. Clean and
replace clogged catch basin filters. For rock and gravel filters, pull away the rocks from the
inlet and clean or replace. An alternative approach would be to use the clogged rock as fill and
put fresh rock around the inlet.
l 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.
Approved as Functionally Equivalent
Ecology has approved products as able to meet the requirements of this BMP. The products did not
pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions
may choose not to accept these products, or may require additional testing prior to consideration for
local use. Products that Ecology has approved as functionally equivalent are available for review on
Ecology’s website at:
https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per-
mittee-guidance-resources/Emerging-stormwater-treatment-technologies
BMP C231: Brush Barrier
Purpose
The purpose of brush barriers is to reduce the transport of coarse sediment from a construction site
by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland
flow.
Conditions of Use
l Brush barriers may be used downslope of disturbed areas that are less than one-quarter acre.
l Brush barriers are not intended to treat concentrated flows, nor are they intended to treat sub-
stantial amounts of overland flow. Any concentrated flows must be directed to a sediment trap-
ping BMP. The only circumstance in which overland flow can be treated solely by a brush
barrier, rather than by a sediment trapping BMP, is when the area draining to the barrier is
small.
l Brush barriers should only be installed on contours.
Design and Installation Specifications
l Height: 2 feet (minimum) to 5 feet (maximum).
l Width: 5 feet at base (minimum) to 15 feet (maximum).
l Filter fabric (geotextile) may be anchored over the brush berm to enhance the filtration ability
of the barrier. Ten-ounce burlap is an adequate alternative to filter fabric.
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BMP C233: Silt Fence
Purpose
Silt fence reduces the transport of coarse sediment from a construction site by providing a temporary
physical barrier to sediment and reducing the runoff velocities of overland flow.
Conditions of Use
Silt fence may be used downslope of all disturbed areas.
l Silt fence shall prevent sediment carried by runoff from going beneath, through, or over the
top of the silt fence, but shall allow the water to pass through the fence.
l Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial
amounts of overland flow. Convey any concentrated flows through the drainage system to a
sediment trapping BMP.
l Do not construct silt fences in streams or use in V-shaped ditches. Silt fences do not provide
an adequate method of silt control for anything deeper than sheet or overland flow.
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Figure II-3.22: Silt Fence
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Design and Installation Specifications
l Use in combination with other construction stormwater BMPs.
l Maximum slope steepness (perpendicular to the silt fence line) 1H:1V.
l Maximum sheet or overland flow path length to the silt fence of 100 feet.
l Do not allow flows greater than 0.5 cfs.
l Use geotextile fabric that meets the following standards. All geotextile properties listed below
are minimum average roll values (i.e., the test result for any sampled roll in a lot shall meet or
exceed the values shown in Table II-3.11: Geotextile Fabric Standards for Silt Fence):
Geotextile Property Minimum Average Roll Value
Polymeric Mesh AOS
(ASTM D4751)
0.60 mm maximum for slit film woven (#30 sieve).
0.30 mm maximum for all other geotextile types (#50 sieve).
0.15 mm minimum for all fabric types (#100 sieve).
Water Permittivity
(ASTM D4491)
0.02 sec-1 minimum
Grab Tensile Strength
(ASTM D4632)
180 lbs. Minimum for extra strength fabric.
100 lbs minimum for standard strength fabric.
Grab Tensile Strength
(ASTM D4632)
30% maximum
Ultraviolet Resistance
(ASTM D4355)
70% minimum
Table II-3.11: Geotextile Fabric Standards for Silt Fence
l Support standard strength geotextiles with wire mesh, chicken wire, 2-inch x 2-inch wire,
safety fence, or jute mesh to increase the strength of the geotextile. Silt fence materials are
available that have synthetic mesh backing attached.
l Silt fence material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum
of six months of expected usable construction life at a temperature range of 0°F to 120°F.
l One-hundred 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 the local jurisdiction.
l Refer to Figure II-3.22: Silt Fence for standard silt fence details. Include the following Stand-
ard Notes for silt fence on construction plans and specifications:
1. The Contractor shall install and maintain temporary silt fences at the locations shown in
the Plans.
2. Construct silt fences in areas of clearing, grading, or drainage prior to starting those
activities.
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3. The silt fence shall have a 2-feet min. and a 2½-feet max. height above the original
ground surface.
4. The geotextile fabric shall be sewn together at the point of manufacture to form fabric
lengths as required. Locate all sewn seams at support posts. Alternatively, two sections
of silt fence can be overlapped, provided that the overlap is long enough and that the
adjacent silt fence sections are close enough together to prevent silt laden water from
escaping through the fence at the overlap.
5. Attach the geotextile fabric on the up-slope side of the posts and secure with staples,
wire, or in accordance with the manufacturer's recommendations. Attach the geotextile
fabric to the posts in a manner that reduces the potential for tearing.
6. Support the geotextile fabric with wire or plastic mesh, dependent on the properties of
the geotextile selected for use. If wire or plastic mesh is used, fasten the mesh securely
to the up-slope side of the posts with the geotextile fabric up-slope of the mesh.
7. Mesh 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 180 lbs. grab tensile strength. The polymeric mesh
must be as resistant to the same level of ultraviolet radiation as the geotextile fabric it
supports.
8. Bury the bottom of the geotextile fabric 4-inches min. below the ground surface. Backfill
and tamp soil in place over the buried portion of the geotextile fabric, so that no flow can
pass beneath the silt fence and scouring cannot occur. When wire or polymeric back-up
support mesh is used, the wire or polymeric mesh shall extend into the ground 3-inches
min.
9. Drive or place the silt fence posts into the ground 18-inches min. A 12–inch min. depth
is allowed if topsoil or other soft subgrade soil is not present and 18-inches cannot be
reached. Increase fence post min. depths by 6 inches if the fence is located on slopes of
3H:1V or steeper and the slope is perpendicular to the fence. If required post depths
cannot be obtained, the posts shall be adequately secured by bracing or guying to pre-
vent overturning of the fence due to sediment loading.
10. Use wood, steel or equivalent posts. The spacing of the support posts shall be a max-
imum of 6-feet. Posts shall consist of either:
l Wood with minimum dimensions of 2 inches by 2 inches by 3 feet. Wood shall be
free of defects such as knots, splits, or gouges.
l No. 6 steel rebar or larger.
l ASTM A 120 steel pipe with a minimum diameter of 1-inch.
l U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft.
l Other steel posts having equivalent strength and bending resistance to the post
sizes listed above.
11. Locate silt fences on contour as much as possible, except at the ends of the fence,
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where the fence shall be turned uphill such that the silt fence captures the runoff water
and prevents water from flowing around the end of the fence.
12. If the fence must cross contours, with the exception of the ends of the fence, place
check dams perpendicular to the back of the fence to minimize concentrated flow and
erosion. The slope of the fence line where contours must be crossed shall not be
steeper than 3H:1V.
l Check dams shall be approximately 1-foot deep at the back of the fence. Check
dams 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.
l Check dams shall consist of crushed surfacing base course, gravel backfill for
walls, or shoulder ballast. Check dams shall be located every 10 feet along the
fence where the fence must cross contours.
l Refer to Figure II-3.23: Silt Fence Installation by Slicing Method for slicing method details. The
following are specifications for silt fence installation using the slicing method:
1. The base of both end posts must be at least 2- to 4-inches above the top of the geo-
textile 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.
2. Install posts 3- to 4-feet apart in critical retention areas and 6- to 7-feet apart in standard
applications.
3. Install posts 24-inches deep on the downstream side of the silt fence, and as close as
possible to the geotextile fabric, enabling posts to support the geotextile fabric from
upstream water pressure.
4. Install posts with the nipples facing away from the geotextile fabric.
5. Attach the geotextile fabric to each post with three ties, all spaced within the top 8-
inches of the fabric. Attach each tie diagonally 45 degrees through the fabric, with each
puncture at least 1-inch vertically apart. Each tie should be positioned to hang on a post
nipple when tightening to prevent sagging.
6. Wrap approximately 6-inches of the geotextile fabric around the end posts and secure
with 3 ties.
7. No more than 24-inches of a 36-inch geotextile fabric is allowed above ground level.
8. Compact the soil immediately next to the geotextile 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. Check and correct
the silt fence installation for any deviation before compaction. Use a flat-bladed shovel
to tuck the fabric deeper into the ground if necessary.
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Figure II-3.23: Silt Fence Installation by Slicing Method
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Maintenance Standards
l Repair any damage immediately.
l Intercept and convey all evident concentrated flows uphill of the silt fence to a sediment trap-
ping BMP.
l Check the uphill side of the silt 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 and remove the trapped sediment.
l Remove sediment deposits when the deposit reaches approximately one-third the height of
the silt fence, or install a second silt fence.
l Replace geotextile fabric that has deteriorated due to ultraviolet breakdown.
BMP C234: Vegetated Strip
Purpose
Vegetated strips reduce the transport of coarse sediment from a construction site by providing a
physical barrier to sediment and reducing the runoff velocities of overland flow.
Conditions of Use
l Vegetated strips may be used downslope of all disturbed areas.
l Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat
substantial amounts of overland flow. Any concentrated flows must be conveyed through the
drainage system to BMP C241: Sediment Pond (Temporary) or other sediment trapping
BMP. The only circumstance in which overland flow can be treated solely by a vegetated strip,
rather than by a sediment trapping BMP, is when the following criteria are met (see Table II-
3.12: Contributing Drainage Area for Vegetated Strips):
Average Contributing Area
Slope
Average Contributing Area Per-
cent Slope
Max Contributing area Flowpath
Length
1.5H : 1V or flatter 67% or flatter 100 feet
2H : 1V or flatter 50% or flatter 115 feet
4H : 1V or flatter 25% or flatter 150 feet
6H : 1V or flatter 16.7% or flatter 200 feet
10H : 1V or flatter 10% or flatter 250 feet
Table II-3.12: Contributing Drainage Area for Vegetated Strips
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Design and Installation Specifications
l The vegetated strip shall consist of a continuous strip of dense vegetation with topsoil for a min-
imum of a 25-foot length along the flowpath. Grass-covered, landscaped areas are generally
not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips
shall consist of undisturbed native growth with a well-developed soil that allows for infiltration
of runoff.
l The slope within the vegetated strip shall not exceed 4H:1V.
l The uphill boundary of the vegetated strip shall be delineated with clearing limits.
Maintenance Standards
l Any areas damaged by erosion or construction activity shall be seeded immediately and pro-
tected by mulch.
l If more than 5 feet of the original vegetated strip width has had vegetation removed or is being
eroded, sod must be installed.
l If there are indications that concentrated flows are traveling across the vegetated strip, storm-
water runoff controls must be installed to reduce the flows entering the vegetated strip, or addi-
tional perimeter protection must be installed.
BMP C235: Wattles
Purpose
Wattles are temporary erosion and sediment control barriers consisting of straw, compost, or other
material that is wrapped in netting made of natural plant fiber or similar encasing material. They
reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sed-
iment.
Conditions of Use
l Wattles shall consist of cylinders of plant material such as weed-free straw, coir, wood chips,
excelsior, or wood fiber or shavings encased within netting made of natural plant fibers
unaltered by synthetic materials.
l Use wattles:
o In disturbed areas that require immediate erosion protection.
o On exposed soils during the period of short construction delays, or over winter months.
o On slopes requiring stabilization until permanent vegetation can be established.
l The material used dictates the effectiveness period of the wattle. Generally, wattles are effect-
ive for one to two seasons.
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l Prevent rilling beneath wattles by entrenching and overlapping wattles to prevent water from
passing between them.
Design Criteria
l See Figure II-3.24: Wattles for typical construction details.
l Wattles are typically 8 to 10 inches in diameter and 25 to 30 feet in length.
l Install wattles perpendicular to the flow direction and parallel to the slope contour.
l Place wattles in shallow trenches, staked along the contour of disturbed or newly constructed
slopes. Dig narrow trenches across the slope (on contour) to a depth of 3- to 5-inches on clay
soils and soils with gradual slopes. On loose soils, steep slopes, and areas with high rainfall,
the trenches should be dug to a depth of 5- to 7- inches, or 1/2 to 2/3 of the thickness of the
wattle.
l Start building trenches and installing wattles from the base of the slope and work up. Spread
excavated material evenly along the uphill slope and compact it using hand tamping or other
methods.
l Construct trenches at intervals of 10- to 25-feet depending on the steepness of the slope, soil
type, and rainfall. The steeper the slope the closer together the trenches.
l Install the wattles snugly into the trenches and overlap the ends of adjacent wattles 12 inches
behind one another.
l Install stakes at each end of the wattle, and at 4-foot centers along entire length of wattle.
l If required, install pilot holes for the stakes using a straight bar to drive holes through the wattle
and into the soil.
l Wooden stakes should be approximately 0.75 x 0.75 x 24 inches min. Willow cuttings or 3/8-
inch rebar can also be used for stakes.
l Stakes should be driven through the middle of the wattle, leaving 2 to 3 inches of the stake pro-
truding above the wattle.
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Figure II-3.24: Wattles
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Maintenance Standards
l Wattles may require maintenance to ensure they are in contact with soil and thoroughly
entrenched, especially after significant rainfall on steep sandy soils.
l Inspect the slope after significant storms and repair any areas where wattles are not tightly
abutted or water has scoured beneath the wattles.
Approved as Functionally Equivalent
Ecology has approved products as able to meet the requirements of this BMP. The products did not
pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions
may choose not to accept these products, or may require additional testing prior to consideration for
local use. Products that Ecology has approved as functionally equivalent are available for review on
Ecology’s website at:
https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per-
mittee-guidance-resources/Emerging-stormwater-treatment-technologies
BMP C236: Vegetative Filtration
Purpose
Vegetative filtration as a BMP is used in conjunction with detention storage in the form of portable
tanks or BMP C241: Sediment Pond (Temporary), BMP C206: Level Spreader, and a pumping sys-
tem with surface intake. Vegetative filtration improves turbidity levels of stormwater discharges by fil-
tering runoff through existing vegetation where undisturbed forest floor duff layer or established lawn
with thatch layer are present. Vegetative filtration can also be used to infiltrate dewatering waste
from foundations, vaults, and trenches as long as runoff does not occur.
Conditions of Use
l For every five acres of disturbed soil use one acre of grass field, farm pasture, or wooded
area. Reduce or increase this area depending on project size, ground water table height, and
other site conditions.
l Wetlands shall not be used for vegetative filtration.
l Do not use this BMP in areas with a high ground water table, or in areas that will have a high
seasonal ground water table during the use of this BMP.
l This BMP may be less effective on soils that prevent the infiltration of the water, such as hard
till.
l Using other effective source control measures throughout a construction site will prevent the
generation of additional highly turbid water and may reduce the time period or area need for
this BMP.
l Stop distributing water into the vegetated filtration area if standing water or erosion results.
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system) will be directed into the permanent Flow Control BMP. If site constraints make locating the
untreated stormwater storage pond difficult, the permanent Flow Control BMP may be divided to
serve as the untreated stormwater storage pond and the post-treatment temporary flow control
pond. A berm or barrier must be used in this case so the untreated water does not mix with the
treated water. Both untreated stormwater storage requirements, and adequate post-treatment flow
control must be achieved. The designer must document in the Construction SWPPP how the per-
manent Flow Control BMP is able to attenuate the discharge from the site to meet the requirements
of Element 3: Control Flow Rates. If the design of the permanent Flow Control BMP was modified
for temporary construction flow control purposes, the construction of the permanent Flow Control
BMP must be finalized, as designed for its permanent function, at project completion.
Maintenance Standards
l Rapid sand filters typically have automatic backwash systems that are triggered by a pre-set
pressure drop across the filter. If the backwash water volume is not large or substantially more
turbid than the untreated stormwater stored in the holding pond or tank, backwash return to
the untreated stormwater pond or tank may be appropriate. However, other means of treat-
ment and disposal may be necessary.
l Screen, bag, and fiber filters must be cleaned and/or replaced when they become clogged.
l Sediment shall be removed from the storage and/or treatment ponds as necessary. Typically,
sediment removal is required once or twice during a wet season and at the decommissioning
of the ponds.
l Disposal of filtration equipment must comply with applicable local, state, and federal reg-
ulations.
BMP C252: Treating and Disposing of High pH Water
Purpose
When pH levels in stormwater rise above 8.5, it is necessary to lower the pH levels to the acceptable
range of 6.5 to 8.5 prior to discharge to surface or ground water. A pH level range of 6.5 to 8.5 is typ-
ical for most natural watercourses, and this neutral pH range is required for the survival of aquatic
organisms. Should the pH rise or drop out of this range, fish and other aquatic organisms may
become stressed and may die.
Conditions of Use
l The water quality standard for pH in Washington State is in the range of 6.5 to 8.5. Storm-
water with pH levels exceeding water quality standards may be either neutralized on site or
disposed of to a sanitary sewer or concrete batch plant with pH neutralization capabilities.
l Neutralized stormwater may be discharged to surface waters under the Construction Storm-
water General permit.
l Neutralized process water such as concrete truck wash-out, hydro-demolition, or saw-cutting
slurry must be managed to prevent discharge to surface waters. Any stormwater
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contaminated during concrete work is considered process wastewater and must not be dis-
charged to waters of the State or stormwater collection systems.
l The process used for neutralizing and/or disposing of high pH stormwater from the site must
be documented in the Construction Stormwater Pollution Prevention Plan.
Causes of High pH
High pH at construction sites is most commonly caused by the contact of stormwater with poured or
recycled concrete, cement, mortars, and other Portland cement or lime containing construction
materials. (See BMP C151: Concrete Handling for more information on concrete handling pro-
cedures). The principal caustic agent in cement is calcium hydroxide (free lime).
Calcium hardness can contribute to high pH values and cause toxicity that is associated with high pH
conditions. A high level of calcium hardness in waters of the state is not allowed. Ground water stand-
ard for calcium and other dissolved solids in Washington State is less than 500 mg/l.
Treating High pH Stormwater by Carbon Dioxide Sparging
Advantages of Carbon Dioxide Sparging
l Rapidly neutralizes high pH water.
l Cost effective and safer to handle than acid compounds.
l CO2 is self-buffering. It is difficult to overdose and create harmfully low pH levels.
l Material is readily available.
The Chemical Process of Carbon Dioxide Sparging
When carbon dioxide (CO2) is added to water (H2O), carbonic acid (H2CO3) is formed which can
further dissociate into a proton (H+) and a bicarbonate anion (HCO3-) as shown below:
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
The free proton is a weak acid that can lower the pH. Water temperature has an effect on the reac-
tion as well. The colder the water temperature is, the slower the reaction occurs. The warmer the
water temperature is, the quicker the reaction occurs. Most construction applications in Washington
State have water temperatures in the 50°F or higher range so the reaction is almost simultaneous.
The Treatment Process of Carbon Dioxide Sparging
High pH water may be treated using continuous treatment, continuous discharge systems. These
manufactured systems continuously monitor influent and effluent pH to ensure that pH values are
within an acceptable range before being discharged. All systems must have fail safe automatic shut
off switches in the event that pH is not within the acceptable discharge range. Only trained operators
may operate manufactured systems. System manufacturers often provide trained operators or train-
ing on their devices.
The following procedure may be used when not using a continuous discharge system:
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1. Prior to treatment, the appropriate jurisdiction should be notified in accordance with the reg-
ulations set by the jurisdiction.
2. Every effort should be made to isolate the potential high pH water in order to treat it separately
from other stormwater on-site.
3. Water should be stored in an acceptable storage facility, detention pond, or containment cell
prior to pH treatment.
4. Transfer water to be treated for pH to the pH treatment structure. Ensure that the pH treat-
ment structure size is sufficient to hold the amount of water that is to be treated. Do not fill the
pH treatment structure completely, allow at least 2 feet of freeboard.
5. The operator samples the water within the pH treatment structure for pH and notes the clarity
of the water. As a rule of thumb, less CO2 is necessary for clearer water. The results of the
samples and water clarity observations should be recorded.
6. In the pH treatment structure, add CO2 until the pH falls into the range of 6.9-7.1. Adjusting
pH to within 0.2 pH units of receiving water (background pH) is recommended. It is unlikely
that pH can be adjusted to within 0.2 pH units using dry ice. Compressed carbon dioxide gas
should be introduced to the water using a carbon dioxide diffuser located near the bottom of
the pH treatment structure, this will allow carbon dioxide to bubble up through the water and
diffuse more evenly.
7. Slowly discharge the water, making sure water does not get stirred up in the process. Release
about 80% of the water from the pH treatment structure leaving any sludge behind. If turbidity
remains above the maximum allowable, consider adding filtration to the treatment train. See
BMP C251: Construction Stormwater Filtration.
8. Discharge treated water through a pond or drainage system.
9. Excess sludge needs to be disposed of properly as concrete waste. If several batches of
water are undergoing pH treatment, sludge can be left in the treatment structure for the next
batch treatment. Dispose of sludge when it fills 50% of the treatment structure volume.
10. Disposal must comply with applicable local, state, and federal regulations.
Treating High pH Stormwater by Food Grade Vinegar
Food grade vinegar that meets FDA standards may be used to neutralize high pH water. Food
grade vinegar is only 4% to 18% acetic acid with the remainder being water. Food grade vinegar
may be used if dosed just enough to lower pH sufficiently. Use a treatment process as described
above for CO2 sparging, but add food grade vinegar instead of CO2.
This treatment option for high pH stormwater does not apply to anything but food grade vinegar.
Acetic acid does not equal vinegar. Any other product or waste containing acetic acid must go
through the evaluation process in Appendix G of Whole Effluent Toxicity Testing Guidance and Test
Review Criteria (Marshall, 2016).
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Disposal of High pH Stormwater
Sanitary Sewer Disposal
Local sewer authority approval is required prior to disposal via the sanitary sewer.
Concrete Batch Plant Disposal
l Only permitted facilities may accept high pH water.
l Contact the facility to ensure they can accept the high pH water.
Maintenance Standards
Safety and materials handling:
l All equipment should be handled in accordance with OSHA rules and regulations.
l Follow manufacturer guidelines for materials handling.
Each operator should provide:
l A diagram of the monitoring and treatment equipment.
l A description of the pumping rates and capacity the treatment equipment is capable of treat-
ing.
Each operator should keep a written record of the following:
l Client name and phone number.
l Date of treatment.
l Weather conditions.
l Project name and location.
l Volume of water treated.
l pH of untreated water.
l Amount of CO2 or food grade vinegar needed to adjust water to a pH range of 6.9-7.1.
l pH of treated water.
l Discharge point location and description.
A copy of this record should be given to the client/contractor who should retain the record for three
years.
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P a g e | 35
C. Correspondence
Department of Ecology – Northwest Regional Office
3190 160th Avenue SE
Bellevue, WA 98008
425-649-7000
City of Renton – Public Works
11055 S Grandy Way
Renton, WA 98057
425-430-7400
P a g e | 36
D. Site Inspection Form
Construction Stormwater Site Inspection Form
Page 1
Project Name MSCR-SBB Permit # 307268 Inspection Date Time
Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre
Print Name:
Approximate rainfall amount since the last inspection (in inches):
Approximate rainfall amount in the last 24 hours (in inches):
Current Weather Clear Cloudy Mist Rain Wind Fog
A. Type of inspection: Weekly Post Storm Event Other
B. Phase of Active Construction (check all that apply):
Pre Construction/installation of erosion/sediment
controls
Clearing/Demo/Grading Infrastructure/storm/roads
Concrete pours Vertical
Construction/buildings
Utilities
Offsite improvements Site temporary stabilized Final stabilization
C. Questions:
1. Were all areas of construction and discharge points inspected? Yes No
2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen Yes No
3. Was a water quality sample taken during inspection? (refer to permit conditions S4 & S5) Yes No
4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less? * Yes No
5. If yes to #4 was it reported to Ecology? Yes No
6. Is pH sampling required? pH range required is 6.5 to 8.5. Yes No
If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken,
and when.
*If answering yes to # 4 record NTU/Transparency with continual sampling daily until turbidity is 25 NTU or less/ transparency is 33
cm or greater.
Sampling Results: Date: 6/20/19
Parameter Method (circle one) Result Other/Note
NTU cm pH
Turbidity tube, meter, laboratory
pH Paper, kit, meter
Construction Stormwater Site Inspection Form
Page 2
D. Check the observed status of all items. Provide “Action Required “details and dates.
Element # Inspection BMPs Status
Good/Ok/Bad
BMP Commentary BMP
failed
Action
required
(describe in
section F)
G Ok B
1
Clearing
Limits
Before beginning land disturbing
activities are all clearing limits,
natural resource areas (streams,
wetlands, buffers, trees) protected
with barriers or similar BMPs? (high
visibility recommended)
2
Construction
Access
Construction access is stabilized
with quarry spalls or equivalent
BMP to prevent sediment from
being tracked onto roads?
Sediment tracked onto the
roadway was cleaned thoroughly at
the end of the day or more
frequent as necessary.
3
Control Flow
Rates
Are flow control measures installed
to control stormwater volumes and
velocity during construction and do
they protect downstream
properties and waterways from
erosion?
If permanent infiltration ponds are
used for flow control during
construction, are they protected
from siltation?
4
Sediment
Controls
All perimeter sediment controls
(e.g. silt fence, wattles, compost
socks, berms, etc.) installed, and
maintained in accordance with the
Stormwater Pollution Prevention
Plan (SWPPP).
Sediment control BMPs (sediment
ponds, traps, filters etc.) have been
constructed and functional as the
first step of grading.
Stormwater runoff from disturbed
areas is directed to sediment
removal BMP.
5
Stabilize
Soils
Have exposed un-worked soils
been stabilized with effective BMP
to prevent erosion and sediment
deposition?
Construction Stormwater Site Inspection Form
Page 3
Element # Inspection BMPs Status
Good/Ok/Bad
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
G Ok B
5
Stabilize Soils
Cont.
Are stockpiles stabilized from erosion,
protected with sediment trapping
measures and located away from drain
inlet, waterways, and drainage
channels?
Have soils been stabilized at the end of
the shift, before a holiday or weekend
if needed based on the weather
forecast?
6
Protect
Slopes
Has stormwater and ground water
been diverted away from slopes and
disturbed areas with interceptor dikes,
pipes and or swales?
Is off-site storm water managed
separately from stormwater generated
on the site?
Is excavated material placed on uphill
side of trenches consistent with safety
and space considerations?
Have check dams been placed at
regular intervals within constructed
channels that are cut down a slope?
7
Drain Inlets
Storm drain inlets made operable
during construction and are protected.
Are existing storm drains within the
influence of the project protected?
8
Stabilize
Channel and
Outlets
Have all on-site conveyance channels
been designed, constructed and
stabilized to prevent erosion from
expected peak flows?
Is stabilization, including armoring
material, adequate to prevent erosion
of outlets, adjacent stream banks,
slopes and downstream conveyance
systems?
9
Control
Pollutants
Are waste materials and demolition
debris handled and disposed of to
prevent contamination of stormwater?
Has cover been provided for all
chemicals, liquid products, petroleum
products, and other material?
Has secondary containment been
provided capable of containing 110%
of the volume?
Were contaminated surfaces cleaned
immediately after a spill incident?
Were BMPs used to prevent
contamination of stormwater by a pH
modifying sources?
Construction Stormwater Site Inspection Form
Page 4
Element # Inspection BMPs Status
Good/Ok/Bad
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
G Ok B
9
Cont.
Wheel wash wastewater is handled
and disposed of properly.
10
Control
Dewatering
Concrete washout in designated areas.
No washout or excess concrete on the
ground.
Dewatering has been done to an
approved source and in compliance
with the SWPPP.
Were there any clean non turbid
dewatering discharges?
11
Maintain
BMP
Are all temporary and permanent
erosion and sediment control BMPs
maintained to perform as intended?
12
Manage the
Project
Has the project been phased to the
maximum degree practicable?
Has regular inspection, monitoring and
maintenance been performed as
required by the permit?
Has the SWPPP been updated,
implemented and records maintained?
13
Protect LID
Is all Bioretention and Rain Garden
Facilities protected from
sedimentation with appropriate BMPs?
Is the Bioretention and Rain Garden
protected against over compaction of
construction equipment and foot
traffic to retain its infiltration
capabilities?
Permeable pavements are clean and
free of sediment and sediment laden-
water runoff. Muddy construction
equipment has not been on the base
material or pavement.
Have soiled permeable pavements
been cleaned of sediments and pass
infiltration test as required by
stormwater manual methodology?
Heavy equipment has been kept off
existing soils under LID facilities to
retain infiltration rate.
Construction Stormwater Site Inspection Form
Page 5
E. Check all areas that have been inspected.
All in place BMPs All disturbed soils All concrete wash out area All material storage areas
All discharge locations All equipment storage areas All construction entrances/exits
F. Elements checked “Action Required” (section D) describe corrective action to be taken. List the element number;
be specific on location and work needed. Document, initial, and date when the corrective action has been completed
and inspected.
Element
#
Description and Location Action Required Completion
Date
Initials
Sign the following certification:
“I certify that this report is true, accurate, and complete, to the best of my knowledge and belief”
Inspected by: (print) (Signature) Date:
Title/Qualification of Inspector:
Construction Stormwater Site Inspection Form
Page 6
Corrective Action Figures:
P a g e | 37
E. Construction Stormwater General Permit (CSWGP)
To be provided upon receipt of approved.
P a g e | 38
F. 303(d) List Waterbodies / TMDL Waterbodies Information
N/A
P a g e | 39
G. Contaminated Site Information
There are no suspected and/or known contaminants associated with the project site.