HomeMy WebLinkAboutRS_ SWPPP 711 Renton_191010_v1Construction Stormwater General Permit
Stormwater Pollution Prevention Plan
(SWPPP)
for
7-Eleven Renton
Prepared for:
The Washington State Department of Ecology
Permittee / Owner Developer Operator / Contractor
7-Eleven, Inc. TBD TBD
11505 SE 168th Ave., Renton WA 98055
Update as necessary.
Certified Erosion and Sediment Control Lead (CESCL)
Name Organization Contact Phone Number
TBD TBD TBD
SWPPP Prepared By
Name Organization Contact Phone Number
Chris Jensen, P.E. Barghausen Consulting
Engineers, Inc.
425-251-6222
SWPPP Preparation Date
October 10, 2019
Project Construction Dates
Activity / Phase Start Date End Date
Site Redevelopment TBD TBD
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Table of Contents
1 Project Information ................................................................................................................. 4
1.1 Existing Conditions ......................................................................................................... 4
1.2 Proposed Construction Activities .................................................................................... 4
2 Construction Stormwater Best Management Practices (BMPs) ............................................ 6
2.1 The 13 Elements ............................................................................................................ 6
2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits .......................................... 6
2.1.2 Element 2: Establish Construction Access .............................................................. 7
2.1.3 Element 3: Control Flow Rates ................................................................................ 8
2.1.4 Element 4: Install Sediment Controls ...................................................................... 9
2.1.5 Element 5: Stabilize Soils ...................................................................................... 10
2.1.6 Element 6: Protect Slopes ..................................................................................... 11
2.1.7 Element 7: Protect Drain Inlets .............................................................................. 12
2.1.8 Element 8: Stabilize Channels and Outlets ........................................................... 13
2.1.9 Element 9: Control Pollutants ................................................................................ 14
2.1.10 Element 10: Control Dewatering ........................................................................... 16
2.1.11 Element 11: Maintain BMPs .................................................................................. 17
2.1.12 Element 12: Manage the Project ........................................................................... 18
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs .................................. 19
3 Pollution Prevention Team ................................................................................................... 20
4 Monitoring and Sampling Requirements .............................................................................. 21
4.1 Site Inspection .............................................................................................................. 21
4.2 Stormwater Quality Sampling ....................................................................................... 21
4.2.1 Turbidity Sampling ................................................................................................. 21
4.2.2 pH Sampling .......................................................................................................... 23
5 Reporting and Record Keeping ........................................................................................... 24
5.1 Record Keeping ............................................................................................................ 24
5.1.1 Site Log Book ........................................................................................................ 24
5.1.2 Records Retention ................................................................................................. 24
5.1.3 Updating the SWPPP ............................................................................................ 24
5.2 Reporting ...................................................................................................................... 25
5.2.1 Discharge Monitoring Reports ............................................................................... 25
5.2.2 Notification of Noncompliance ............................................................................... 25
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List of Tables
Table 3 – pH-Modifying Sources ............................................................................................. 14
Table 5 – Management .............................................................................................................. 18
Table 7 – Team Information ..................................................................................................... 20
Table 8 – Turbidity Sampling Method ..................................................................................... 21
Table 9 – pH Sampling Method ................................................................................................ 23
List of Appendices
Appendix/Glossary
A. Site Map
B. BMP Detail
D. Site Inspection Form
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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: 7-Eleven Renton
Street/Location: 11505 SE 168th Ave.
City: Renton State: WA Zip code: 98055
Receiving waterbody: Soos Creek
1.1 Existing Conditions
Total acreage (including support activities such as off-site equipment staging yards, material
storage areas, borrow areas).
Total acreage: .68
Disturbed acreage: .1
Existing structures: The site currently consists of asphalt and concrete paving used primarily for
an existing fueling pad, parking and an existing 7-Eleven Convenience
Store. The site also includes an area for underground storage tanks.
Landscape
topography:
The site contains mild slopes with grades ranging from 1-8 percent sloping
from west to east.
Drainage patterns: The existing drainage patterns are such that stormwater sheet flows into
existing catch basins and flows into a the public storm system that runs
along 116th Avenue S,E.
Existing Vegetation: The site has some no existing landscape islands, however pervious
surfaces exist along the west property line.
Critical Areas (wetlands, streams, high erosion
risk, steep or difficult to stabilize slopes):
This project is not located in a critical area.
1.2 Proposed Construction Activities
Description of site development (example: subdivision):
The project includes the replacement of three existing underground storage tanks (UST) with 2
UST's, as well as the fueling concrete pad and fueling dispensers. The existing fueling canopy
shall remain. ADA improvements include the repaving of the ADA parking stall and aisle.
Description of construction activities (example: site preparation, demolition, excavation):
Construction activities will include clearing and grubbing existing asphalt and concrete
pavement and removal and installation of underground storage tanks and fueling dispensers.
Description of site drainage including flow from and onto adjacent properties. Must be consistent
with Site Map in Appendix A:
Stormwater generally flows from west to east into the existing catch basins located onsite and
discharges into the conveyance system that runs along 116th Avenue SE.
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Description of final stabilization (example: extent of revegetation, paving, landscaping):
Final site stabilization will include the installation of hardscapes, such as asphalt and concrete
pavement. The developed condition of the site will retain the existing drainage pattern and sheet
flow stormwater to on-site catch basins and maintain the offsite discharge location. A site map
has been provided in Appendix A.
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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
List and describe BMPs: In order to protect adjacent properties and to reduce the area of soil
exposed to construction, the limits of construction will be clearly marked and enclosed within a
construction fence prior to any land disturbing activities. This fence will encompass all areas
subject to construction, as well as delineate all areas where no construction is to take place.
Refer to Appendix B: Construction BMPs for detailed drawings of the proposed BMPs. The
proposed BMPs relevant to vegetation preservation/clearing limits is:
• BMP C103: High Visibility Plastic or Metal Fence
Installation Schedules: BMPs listed above (Silt Fence and High Visibility Plastic or Metal Fence)
will be installed prior to any land disturbing activity.
Inspection and Maintenance plan: TBD
Responsible Staff: TTBD
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2.1.2 Element 2: Establish Construction Access
List and describe BMPs: A construction entrance is not needed for this project since the
construction vehicles will have minimal contact with exposed soil. Wheel washing and daily
sweeping will be required should any dirt be found on tires of vehicles to prevent soil transfer onto
public roads.
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
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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
List and describe BMPs: NA
Installation Schedules: NA
Inspection and Maintenance plan: NA
Responsible Staff: NA
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2.1.4 Element 4: Install Sediment Controls
List and describe BMPs: The majority of the project site is impervious and only has minimal
landscaping on the west side of the site retained by a wall. The improvements do not include
any reconstruction of the wall, hence eliminating the possibility of soil/sediment sheetwash from
upslope.
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
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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: TBD End date: TBD
Will you construct during the wet season?
TBD
List and describe BMPs: Soils exposed and unworked for the time period specified above shall
be stabilized with the application of effective BMPs to prevent erosion throughout the duration of
the project. Soil stockpiles shall be stabilized or covered using plastic sheeting and where
possible, located away from storm inlets, waterways, and drainage channels . Refer to Appendix
B for detailed drawings of the BMPs used. The proposed BMPs specific to Soil Stabilization
are:
• BMP C123: Plastic Covering
Installation Schedules: BMPs shall be implemented as soon as land disturbing activity begins
and installed where applicable for the duration of the project.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
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2.1.6 Element 6: Protect Slopes
Will steep slopes be present at the site during construction?
Yes No
List and describe BMPs: N/A
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
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2.1.7 Element 7: Protect Drain Inlets
List and describe BMPs: All storm drain inlets must be protected to prevent unfiltered or
untreated water from entering the drainage conveyance system. However, the first priority is to
keep all access roads clean of sediment and keep water from washing streets separate from
entering storm drains until treatment can be provided. Storm Drain Inlet Protection will be
implemented for all drainage inlets and culverts that could potentially be impacted by sediment-
laden runoff on or near the project site. This includes inlets and culverts located offsite. Inlet
protection devices shall be cleaned and replaced or removed when sediment has filled a third of
the available storage (unless a different standard is specified by the product manufacturer). The
following inlet protection measures will be proposed for this project:
• BMP C220: Storm Drain Inlet Protection
Installation Schedules: Storm Drain Inlet Protection will be provided at the start of the project
and will be maintained for the duration of the project.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
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2.1.8 Element 8: Stabilize Channels and Outlets
Provide stabilization, including armoring material, adequate to prevent erosion of outlets,
adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all
conveyance systems.
List and describe BMPs: The project site does not consist of open channels, steep slopes, or
streams. Sediment from surface water deposits will be minimized through inlet protection of
existing catch basins (Element 7).
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
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2.1.9 Element 9: Control Pollutants
List and describe BMPs: All pollutants, including waste materials and demolition debris, that
occur on site will be handled and disposed of in a manner that does not cause contamination of
stormwater. Good housekeeping and preventative measures will be taken to ensure that the
site will be kept clean, well-organized, and free of debris. The following BMPs will be
implemented:
• 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.
• In order to perform emergency repairs on site, temporary plastic will be placed beneath
and, if raining, over the vehicle.
• Any chemicals stored in the construction areas will conform to the appropriate source
control BMPs listed in Volume IV of the Ecology stormwater manual. All chemicals shall
have cover, containment, and protection provided on site, pursuant to BMP C153 for
Material Delivery, Storage and Containment.
Proposed BMPs applicable to Pollutant Control:
• BMP C140: Dust Control
• BMP C151: Concrete Handling
• BMP C 152: Sawcutting and Surface Pollution Prevention
• BMP C154: Concrete Washout Area
Installation Schedules: BMPs shall be installed as necessary to control pollutants for the
duration of construction.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
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
Will pH-modifying sources be present on-site?
Yes No If yes, check the source(s).
Table 3 – pH-Modifying Sources
None
Bulk cement
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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: ]
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
Discharge clean, non-turbid de-watering water, such as well-point groundwater, to
systems tributary to, or directly into surface waters of the state, as specified in Element
No. 8, provided the de-watering flow does not cause erosion or flooding of receiving
waters or interfere with the operation of the system. Do not route clean dewatering
water through stormwater sediment ponds. Note that "surface waters of the state" may
exist on a construction site as well as off site; for example, a creek running through a
site.
Highly turbid or contaminated dewatering water shall be handled separately from
stormwater.
Clean, non-turbid dewatering water, such as well-point ground water, can be discharged
to systems tributary to, or directly into surface waters of the state, provided the
dewatering flow does not cause erosion or flooding of receiving waters. Clean
dewatering water should not be routed through stormwater sediment ponds.
Other dewatering disposal options may include:
o Transport off site in a vehicle, such as a vacuum flush truck, for legal disposal in
a manner that does not pollute state waters.
o Infiltration.
o Ecology-approved on-site chemical treatment or other suitable treatment
technologies.
o Sanitary sewer discharge with local sewer district approval, if there is no other
option.
o Use of a sedimentation bag with outfall to a ditch or swale for small volumes of
localized dewatering.
The project may exhibit high groundwater elevations. Depending on the time of year,
dewatering activities may occur during the installation of on-site stormwater conveyance
systems and/or excavation activities.
Installation Schedules: Dewatering controls will be installed prior to any significant excavation
activities.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
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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.
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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.
Check all the management BMPs that apply at your site:
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)
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2.1.13 Element 13: Protect Low Impact Development (LID) BMPs
This project does not proposed any Low Impact Development BMPs to be implemented as part
of this proposal.
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3 Pollution Prevention Team
Table 7 – Team Information
Title Name(s) Phone Number
Certified Erosion and
Sediment Control Lead
(CESCL)
TBD TBD
Resident Engineer Chris Jensen, P.E. 425-251-6222
Emergency Ecology
Contact
Staff on Duty 425-649-7130
Emergency Permittee/
Owner Contact
TBD TBD
Non-Emergency Owner
Contact
TBD TBD
Monitoring Personnel TBD TBD
Ecology Regional Office Northwest Region 425-649-7000
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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
File a blank form under Appendix D.
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:
Check the analysis method you will use:
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:
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1. Review the SWPPP for compliance with Special Condition S9. Make appropriate
revisions within 7 days of the date the discharge exceeded the benchmark.
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.
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
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.
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4.2.2 pH Sampling
pH monitoring is required for “Significant concrete work” (i.e., greater than 1000 cubic yards
poured concrete over the life of the project). The use of recycled concrete or engineered soils
(soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln
dust [CKD] or fly ash) also requires pH monitoring.
For significant concrete work, pH sampling will start the first day concrete is poured and
continue until it is cured, typically three (3) weeks after the last pour.
For engineered soils and recycled concrete, pH sampling begins when engineered soils or
recycled concrete are first exposed to precipitation and continues until the area is fully
stabilized.
If the measured pH is 8.5 or greater, the following measures will be taken:
1. Prevent high pH water from entering storm sewer systems or surface water.
2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate
technology such as carbon dioxide (CO2) sparging (liquid or dry ice).
3. Written approval will be obtained from Ecology prior to the use of chemical treatment
other than CO2 sparging or dry ice.
Method for sampling pH:
Check the analysis method you will use:
Table 9 – pH Sampling Method
pH meter
pH test kit
Wide range pH indicator paper
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5 Reporting and Record Keeping
5.1 Record Keeping
5.1.1 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
5.1.2 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.
5.1.3 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.
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5.2 Reporting
5.2.1 Discharge Monitoring Reports
Cumulative soil disturbance is less than one (1) acre; therefore, Discharge Monitoring
Reports (DMRs) will not be submitted to Ecology because water quality sampling is not being
conducted at the site.
5.2.2 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.
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Appendix/Glossary
A. Site Map
B. BMP Detail
C. Site Inspection Form
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
Dial 811
Callbefore you dig.
below.Know what's
7-ELEVEN RENTON
28 20828.002.doc
BMP C103: High Visibility Fence
Purpose
Fencing is intended to:
1. Restrict clearing to approved limits.
2. Prevent disturbance of sensitive areas, their buffers, and other areas required
to be left undisturbed.
3. Limit construction traffic to designated construction entrances, exits, or
internal roads.
4. 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:
· At the boundary of sensitive areas, their buffers, and other areas required to be
left uncleared.
· As necessary to control vehicle access to and on the site.
Design and 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 (p.367) 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.
Maintenance Standards
If the fence has been damaged or visibility reduced, it shall be repaired or replaced
immediately and visibility restored.
37 20828.002.doc
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
In areas (including roadways) subject to surface and air movement of dust where on-
site and off-site impacts to roadways, drainage ways, or surface waters are likely.
Design and Installation Specifications
· Vegetate or mulch areas that will not receive vehicle traffic. In areas where
planting, mulching, or paving is impractical, apply gravel or landscaping rock.
· 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.
· Construct natural or artificial windbreaks or windscreens. These may be
designed as enclosures for small dust sources.
· Sprinkle the site with water until surface is wet. Repeat as needed. To prevent
carryout of mud onto street, refer to BMP C105: Stabilized Construction Entrance
Exit (p.270)
· 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.
· 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 suppressant. Local governments may approve
other dust palliatives such as calcium chloride or PAM.
· PAM (BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection (p.300))
added to water at a rate of 0.5 lbs. per 1,000 gallons of water per acre and
applied from a water truck is more effective 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 transported by
wind. Adding PAM may actually reduce the quantity of water needed for dust
control. Use of PAM could be a cost-effective dust control method.
Techniques that can be used for unpaved roads and lots include:
· Lower speed limits. High vehicle speed increases the amount of dust stirred up
from unpaved roads and lots.
· Upgrade the road surface strength by improving particle size, shape, and mineral
types that make up the surface and base materials.
· 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.
· Use geotextile fabrics to increase the strength of new roads or roads undergoing
reconstruction.
· Encourage the use of alternate, paved routes, if available.
38 20828.002.doc
· Restrict use of paved roadways by tracked vehicles and heavy trucks to prevent
damage to road surface and base.
· 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.
· Pave unpaved permanent roads and other trafficked areas.
· Use vacuum street sweepers.
· Remove mud and other dirt promptly so it does not dry and then turn into dust.
· Limit dust-causing work on windy days.
· Contact your local Air Pollution Control Authority for guidance and training on
other dust control measures. Compliance with the local Air Pollution Control
Authority constitutes compliance with this BMP.
·
Maintenance Standards
Respray area as necessary to keep dust to a minimum.
40 20828.002.doc
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 discharge to surface waters of the State is prohibited. Use
this BMP to minimize and eliminate concrete, concrete process water, and concrete
slurry from entering waters of the state.
Conditions of Use
Any time concrete is used, utilize these management practices. Concrete construction
projects include, but are not limited to, the following:
· Curbs
· Sidewalks
· Roads
· Bridges
· Foundations
· Floors
· Runways
Design and Installation Specifications
· Assure that washout of concrete trucks, chutes, pumps, and internals is
performed at an approved off-site location or in designated concrete washout
areas. Do not wash out concrete trucks onto the ground, or into storm drains,
open ditches, streets, or streams. Refer to BMP C154: Concrete Washout Area
(p.317) for information on concrete washout areas.
· 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.
· Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats,
and trowels into formed areas only.
· Wash equipment difficult to move, such as concrete pavers in areas that do not
directly drain to natural or constructed stormwater conveyances.
· Do not allow washdown from areas, such as concrete aggregate driveways, to
drain directly to natural or constructed stormwater conveyances.
· Contain washwater and leftover product in a lined container when no formed
areas are available. Dispose of contained concrete in a manner that does not
violate ground water or surface water quality standards.
· Always use forms or solid barriers for concrete pours, such as pilings, within 15-
feet of surface waters.
· Refer to BMP C252: High pH Neutralization Using CO2 (p.409) and BMP C253:
pH Control for High pH Water (p.412) for pH adjustment requirements.
· Refer to the Construction Stormwater General Permit for pH monitoring
requirements if the project involves one of the following activities:
41 20828.002.doc
o Significant concrete work (greater than 1,000 cubic yards poured concrete
or recycled concrete used over the life of a project).
o The use of engineered 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.
42 20828.002.doc
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 surface
waters of the State is prohibited. Use this BMP to minimize and eliminate process water
and slurry created through sawcutting or surfacing from entering waters of the State.
Conditions of Use
Utilize these management practices anytime sawcutting or surfacing operations take
place. Sawcutting and surfacing operations include, but are not limited to, the following:
· Sawing
· Coring
· Grinding
· Roughening
· Hydro-demolition
· Bridge and road surfacing
Design and Installation Specifications
· Vacuum slurry and cuttings during cutting and surfacing operations.
· Slurry and cuttings shall not remain on permanent concrete or asphalt pavement
overnight.
· Slurry and cuttings shall not drain to any natural or constructed drainage
conveyance including stormwater systems. This may require temporarily blocking
catch basins.
· Dispose of collected slurry and cuttings in a manner that does not violate ground
water or surface water quality standards.
· 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 process water in a manner
that does not violate ground water or surface water quality standards.
· Handle and dispose 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 vacuum trucks.
45 20828.002.doc
BMP C154: Concrete Washout Area
Purpose
Prevent or reduce the discharge of pollutants to stormwater from concrete waste by
conducting washout off-site, or performing on-site washout in a designated area to
prevent pollutants from entering surface waters or ground water.
Conditions of Use
Concrete washout area best management practices are implemented on construction
projects where:
· Concrete is used as a construction material
· It is not possible to dispose of all concrete wastewater and washout off-site
(ready mix plant, etc.).
· Concrete trucks, pumpers, or other concrete coated equipment are washed on-
site.
· Note: If less than 10 concrete trucks or pumpers need to be washed out on-site,
the washwater may be disposed of in a formed area awaiting concrete or an
upland disposal site where it will not contaminate surface or ground water. The
upland disposal site shall be at least 50 feet from sensitive areas such as storm
drains, open ditches, or water bodies, including wetlands.
Design and Installation Specifications
Implementation
The following steps will help reduce stormwater pollution from concrete wastes:
· Perform washout of concrete trucks at an approved off-site location or in
designated concrete washout areas only.
· Do not wash out concrete trucks onto the ground, or into storm drains, open
ditches, streets, or streams.
· Do not allow excess concrete to be dumped on-site, except in designated
concrete washout areas.
· Concrete washout areas may be prefabricated concrete washout containers, or
self-installed structures (above-grade or below-grade).
· Prefabricated containers are most resistant to damage and protect against spills
and leaks. Companies may offer delivery service and provide regular
maintenance and disposal of solid and liquid waste.
· If self-installed concrete washout areas are used, below-grade structures are
preferred over above-grade structures because they are less prone to spills and
leaks.
· Self-installed above-grade structures should only be used if excavation is not
practical.
Education
· Discuss the concrete management techniques described in this BMP with the
ready-mix concrete supplier before any deliveries are made.
46 20828.002.doc
· Educate employees and subcontractors on the concrete waste management
techniques described in this BMP.
· Arrange for contractor’s superintendent or Certified Erosion and Sediment
Control Lead (CESCL) to oversee and enforce concrete waste management
procedures.
· A sign should be installed adjacent to each temporary concrete washout facility
to inform concrete equipment operators to utilize the proper facilities.
Contracts
Incorporate requirements for concrete waste management into concrete supplier and
subcontractor agreements.
Location and Placement
· Locate washout area at least 50 feet from sensitive areas such as storm drains,
open ditches, or water bodies, including wetlands.
· Allow convenient access for concrete trucks, preferably near the area where the
concrete is being poured.
· If trucks need to leave a paved area to access washout, prevent track-out with a
pad of rock or quarry spalls (see BMP C105: Stabilized Construction Entrance /
Exit (p.270)). These areas should be far enough away from other construction
traffic to reduce the likelihood of accidental damage and spills.
· The number of facilities you install should depend on the expected demand for
storage capacity.
· On large sites with extensive concrete work, washouts should be placed in
multiple locations for ease of use by concrete truck drivers.
On-site Temporary Concrete Washout Facility, Transit Truck Washout
Procedures:
· Temporary concrete washout facilities shall be located a minimum of 50 feet from
sensitive areas including storm drain inlets, open drainage facilities, and
watercourses. See Figure II-4.1.7a Concrete Washout Area (p.322), Figure II-
4.1.7b Concrete Washout Area (p.323), and Figure II-4.1.8 Prefabricated
Concrete Washout Container w/Ramp (p.324).
· Concrete washout facilities shall be constructed and maintained in sufficient
quantity and size to contain all liquid and concrete waste generated by washout
operations.
· Washout of concrete trucks shall be performed in designated areas only.
· Concrete washout from concrete pumper bins can be washed into concrete
pumper trucks and discharged into designated washout area or properly
disposed of off-site.
· Once concrete wastes are washed into the designated area and allowed to
harden, the concrete should be broken up, removed, and disposed of per
applicable solid waste regulations. Dispose of hardened concrete on a regular
basis.
· Temporary Above-Grade Concrete Washout Facility
47 20828.002.doc
· Temporary concrete washout facility (type above grade) should be constructed
as shown on the details below, with a recommended minimum length and
minimum width of 10 ft, but with sufficient quantity and volume to contain all liquid
and concrete waste generated by washout operations.
· Plastic lining material should be a minimum of 10 mil polyethylene sheeting and
should be free of holes, tears, or other defects that compromise the
impermeability of the material.
· Temporary Below-Grade Concrete Washout Facility.
· Temporary concrete washout facilities (type below grade) should be constructed
as shown on the details below, with a recommended minimum length and
minimum width of 10 ft. The quantity and volume should be sufficient to contain
all liquid and concrete waste generated by washout operations.
· Lath and flagging should be commercial type.
· Plastic lining material shall be a minimum of 10 mil polyethylene sheeting and
should be free of holes, tears, or other defects that compromise the
impermeability of the material.
· Liner seams shall be installed in accordance with manufacturers’
recommendations.
· Soil base shall be prepared free of rocks or other debris that may cause tears
· or holes in the plastic lining material.
Maintenance Standards
Inspection and Maintenance
· Inspect and verify that concrete washout BMPs are in place prior to the
commencement of concrete work.
· During periods of concrete work, inspect daily to verify continued performance.
o Check overall condition and performance.
o Check remaining capacity (% full).
o If using self-installed washout facilities, verify plastic liners are intact and
sidewalls are not damaged.
o If using prefabricated containers, check for leaks.
· Washout facilities shall be maintained to provide adequate holding capacity with
a minimum freeboard of 12 inches.
· Washout facilities must be cleaned, or new facilities must be constructed and
ready for use once the washout is 75% full.
· If the washout is nearing capacity, vacuum and dispose of the waste material in
an approved manner.
· Do not discharge liquid or slurry to waterways, storm drains or directly onto
ground.
· Do not use sanitary sewer without local approval.
· Place a secure, non-collapsing, non-water collecting cover over the concrete
washout facility prior to predicted wet weather to prevent accumulation and
overflow of precipitation.
48 20828.002.doc
· Remove and dispose of hardened concrete and return the structure to a
functional condition. Concrete may be reused on-site or hauled away for disposal
or recycling.
· When you remove materials from the self-installed concrete washout, build a new
structure; or, if the previous structure is still intact, inspect for signs of weakening
or damage, and make any necessary repairs. Re-line the structure with new
plastic after each cleaning.
Removal of Temporary Concrete Washout Facilities
· When temporary concrete washout facilities are no longer required for the work,
the hardened concrete, slurries and liquids shall be removed and properly
disposed of.
· Materials used to construct temporary concrete washout facilities shall be
removed from the site of the work and disposed of or recycled.
· Holes, depressions or other ground disturbance caused by the removal of the
temporary concrete washout facilities shall be backfilled, repaired, and stabilized
to prevent erosion.
DEPARTMENT OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.1.7a
Concrete Washout Area
Revised June 2015
NOT TO SCALE
Sandbag
Berm
10 mil plastic lining
1 m
Section A-A
Plan
Type "Below Grade"
Lath and flagging
on 3 sides
3m Minimum
Varies
Sandbag
Berm
10 mil plastic lining
Type "Above Grade" with Wood Planks
Section B-B
Plan
3m Minimum
Stake (typ.)
AA
10 mil plastic lining
Varies
Two-stacked
2x12 rough
wood frame
BB
10 mil
plastic lining
Wood frame
securely fastened
around entire
perimeter with two
stakes
Notes:
1. Actual layout
determined in the field.
2. A concrete washout
sign shall be installed
within 10 m of the
temporary concrete
washout facility.
DEPARTMENT OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.1.7b
Concrete Washout Area
Revised June 2015
NOT TO SCALE
Type "Above Grade" with Straw Bales
Plan
Section B-B
Concrete Washout Sign
Detail (or equivalent)
Staple Detail
Wood or
metal stakes
(2 per bale)
Staples
(2 per bale)
Straw bale
10 mil plastic lining
Native material
(optional)
Binding wire
CONCRETE
WASHOUT
915 mm
915 mm
Plywood
1200 mm x 610 mm
painted white
Black letters
150 mm height
Lag screws
(12.5 mm)
Wood post
(89 mm x 89 mm
x 2.4 m)
50 mm
200 mm 3.05 mm dia.
steel wire
3m Minimum
Varies
10 mil plastic lining
Stake (typ)
Straw bale
(typ.)
BB
Notes:
1. Actual layout
determined in the field.
2. The concrete washout
sign shall be installed
within 10 m of the
temporary concrete
washout facility.
DEPARTMENT OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.1.8
Prefabricated Concrete Washout Container
w/Ramp
Revised June 2015
NOT TO SCALE
52 20828.002.doc
BMP C160: Certified Erosion and Sediment Control Lead
Purpose
The project proponent designates at least one person as the responsible representative
in charge of erosion and sediment control (ESC), and water quality protection. The
designated person shall be the Certified Erosion and Sediment Control Lead (CESCL)
who is responsible for ensuring compliance with all local, state, and federal erosion and
sediment control and water quality requirements.
Conditions of Use
A CESCL shall be made available on projects one acre or larger that discharge
stormwater to surface waters of the state. Sites less than one acre may have a person
without CESCL certification conduct inspections; sampling is not required on sites that
disturb less than an acre.
The CESCL shall:
· 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 (see details below). Ecology will maintain a
list of ESC training and certification providers at:
http://www.ecy.wa.gov/programs/wq/stormwater/cescl.html
OR
· Be a Certified Professional in Erosion and Sediment Control (CPESC); for
additional information go to: http://www.envirocertintl.org/cpesc/
Specifications
· Certification shall remain valid for three years.
· The CESCL shall have authority to act on behalf of the contractor or developer
and shall be available, or on-call, 24 hours per day throughout the period of
construction.
· The Construction SWPPP shall include the name, telephone number, fax
number, and address of the designated CESCL.
· A CESCL may provide inspection and compliance services for multiple
construction projects in the same geographic region.
Duties and responsibilities of the CESCL shall include, but are not limited to the
following:
· Maintaining permit file on site at all times which includes the Construction
SWPPP and any associated permits and plans.
· Directing BMP installation, inspection, maintenance, modification, and removal.
· Updating all project drawings and the Construction SWPPP with changes made.
· Completing any sampling requirements including reporting results using
WebDMR.
· Keeping daily logs, and inspection reports. Inspection reports should include:
o Inspection date/time.
53 20828.002.doc
o Weather information; general conditions during inspection and
approximate amount of precipitation since the last inspection. A summary
or list of all BMPs implemented, including observations of all
erosion/sediment control structures or practices. The following shall be
noted:
Locations of BMPs inspected.
Locations of BMPs that need maintenance.
Locations of BMPs that failed to operate as designed or intended
Locations of where additional or different BMPs are required.
o Visual monitoring results, including a description of discharged
stormwater.
o The presence of suspended sediment, turbid water, discoloration, and oil
sheen shall be noted, as applicable.
o Any water quality monitoring performed during inspection.
o General comments and notes, including a brief description of any BMP
repairs, maintenance or installations made as a result of the inspection.
o Facilitate, participate in, and take corrective actions resulting from
inspections performed by outside agencies or the owner.
54 20828.002.doc
BMP C162: Scheduling
Purpose
Sequencing a construction project reduces the amount and duration of soil exposed to
erosion by wind, rain, runoff, and vehicle tracking.
Conditions of Use
The construction sequence schedule is an orderly listing of all major land-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 surface ground cover leaves a
site vulnerable to accelerated erosion. Construction procedures that limit land clearing
provide timely installation of erosion and sedimentation controls, and restore protective
cover quickly can significantly reduce the erosion potential of a site.
Design Considerations
· Minimize construction during rainy periods.
· 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 portion. Practice staged seeding in order to
revegetate cut and fill slopes as the work progresses.
55 20828.002.doc
BMP C220: Storm Drain Inlet Protection
Purpose
Storm drain inlet protection prevents coarse sediment from entering drainage systems
prior to permanent stabilization of the disturbed area.
Conditions of Use
Use storm drain inlet protection at inlets that are operational before permanent
stabilization of the disturbed drainage area. Provide protection for all storm drain inlets
downslope and within 500 feet of a disturbed or construction area, unless conveying
runoff entering catch basins to a sediment pond or trap.
Also consider inlet protection for lawn and yard drains on new home construction.
These small and numerous drains coupled with lack of gutters in new home
construction 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 pre- vent sediment from entering the system until completion of landscaping.
Provide 18- inches of sod around each finished lawn and yard drain.
Table II-4.2.2 Storm Drain Inlet Protection (p.358) lists several options for inlet
protection. All of the methods for storm drain inlet protection tend to plug and require a
high frequency of maintenance. Limit drainage areas to one acre or less. Possibly
provide emergency overflows with additional end-of-pipe treatment where stormwater
ponding would cause a hazard.
Design and Installation Specifications
Excavated Drop Inlet Protection - An excavated impoundment around the storm drain.
Sediment settles out of the stormwater prior to entering the storm drain.
· Provide a depth of 1-2 ft as measured from the crest of the inlet structure.
· Slope sides of excavation no steeper than 2H:1V.
· Minimum volume of excavation 35 cubic yard.
· Shape basin to fit site with longest dimension oriented toward the longest inflow
area.
· Install provisions for draining to prevent standing water problems.
· Clear the area of all debris.
· Grade the approach to the inlet uniformly.
· Drill weep holes into the side of the inlet.
· Protect weep holes with screen wire and washed aggregate.
· Seal weep holes when removing structure and stabilizing area.
· Build a temporary dike, if necessary, to the down slope side of the structure to
prevent bypass flow.
Block and Gravel Filter - A barrier formed around the storm drain inlet with standard
concrete blocks and gravel. See Figure II-4.2.8 Block and Gravel Filter (p.360).
· Provide a height of 1 to 2 feet above inlet.
56 20828.002.doc
· Recess the first row 2-inches into the ground for stability.
· Support subsequent courses by placing a 2x4 through the block opening.
· Do not use mortar.
· Lay some blocks in the bottom row on their side for dewatering the pool.
· Place hardware cloth or comparable wire mesh with ½-inch openings over all
· Block openings.
· Place gravel just below the top of blocks on slopes of 2H:1V or flatter.
· An alternative design is a gravel donut.
· Provide an inlet slope of 3H:1V.
· Provide an outlet slope of 2H:1V.
· Provide a1-foot wide level stone area between the structure and the inlet.
· Use inlet slope stones 3 inches in diameter or larger.
· Use gravel ½- to ¾-inch at a minimum thickness of 1-foot for the outlet slope.
DEPARTMENT OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.8
Block and Gravel Filter
Revised August 2015
NOT TO SCALE
Plan View
A
A
Section A-A
Drain grate
Concrete block
Gravel backfill
Less than5% slope
Gravel backfill
Concrete block
Water
Overflow
water
Drop inlet
Ponding height
Wire screen or
filter fabric
Notes:
1. Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less
than 5%)
2. Excavate a basin of sufficient size adjacent to the drop inlet.
3. The top of the structure (ponding height) must be well below the ground elevation
downslope to prevent runoff from bypassing the inlet. A temporary dike may be
necessary on the downslope side of the structure.
58 20828.002.doc
Gravel and Wire Mesh Filter - A gravel barrier placed over the top of the inlet. This
structure does not provide an overflow.
· Use a hardware cloth or comparable wire mesh with ½-inch openings.
· Use coarse aggregate.
· Provide a height 1-foot or more, 18-inches wider than inlet on all sides.
· Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot
beyond each side of the inlet structure.
· Overlap the strips if more than one strip of mesh is necessary.
· Place coarse aggregate over the wire mesh.
· Provide at least a 12-inch depth of gravel over the entire inlet opening and
extend at least 18-inches on all sides.
Catchbasin Filters – Use inserts designed by manufacturers for construction sites. The
limited sediment storage capacity increases the amount of inspection and maintenance
required, which may be daily for heavy sediment loads. To reduce maintenance
requirements combine a catchbasin filter with another type of inlet protection. This type
of inlet protection provides flow bypass without overflow and therefore may be a better
method for inlets located along active rights-of-way.
· Provides 5 cubic feet of storage.
· Requires dewatering provisions.
· Provides a high-flow bypass that will not clog under normal use at a construction
site.
· Insert the catchbasin filter in the catchbasin just below the grating.
Curb Inlet Protection with Wooden Weir – Barrier formed around a curb inlet with a
wooden frame and gravel.
· Use wire mesh with ½-inch openings.
· Use extra strength filter cloth.
· Construct a frame.
· Attach the wire and filter fabric to the frame.
· Pile coarse washed aggregate against wire/fabric.
· Place weight on frame anchors.
Block and Gravel Curb Inlet Protection – Barrier formed around a curb inlet with
concrete blocks and gravel. See Figure II-4.2.9 Block and Gravel Curb Inlet Protection
(p.363).
· Use wire mesh with ½-inch openings.
· Place two concrete blocks on their sides abutting the curb at either side of the
inlet opening. These are spacer blocks.
· Place a 2x4 stud through the outer holes of each spacer block to align the front
blocks.
· Place blocks on their sides across the front of the inlet and abutting the spacer
blocks.
· Place wire mesh over the outside vertical face
· Pile coarse aggregate against the wire to the top of the barrier.
59 20828.002.doc
Curb and Gutter Sediment Barrier – Sandbag or rock berm (riprap and aggregate) 3 feet
high and 3 feet wide in a horseshoe shape. See Figure II-4.2.10 Curb and Gutter Barrier
(p.364).
· 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.
· Construct a horseshoe shaped sedimentation trap on the outside of the berm
sized to sediment trap standards for protecting a culvert inlet.
Maintenance Standards
· Inspect catch basin filters frequently, especially after storm events. Clean and
replace clogged inserts. For systems with clogged stone filters: pull away the
stones from the inlet and clean or replace. An alternative approach would be to
use the clogged stone as fill and put fresh stone around the inlet.
· Do not wash sediment into storm drains while cleaning. Spread all excavated
material evenly over the surrounding land area or stockpile and stabilize as
appropriate.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C220: Storm
Drain Inlet Protection. The products did not pass through the Technology Assessment
Protocol – Ecology (TAPE) process. Local jurisdictions may choose not to accept this
product approved as equivalent, or may require additional testing prior to consideration
for local use. The products are available for review on Ecology’s website at
http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html
DEPARTMENT OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.9
Block and Gravel Curb Inlet Protection
Revised August 2015
NOT TO SCALE
Plan View
A
A
Section A-A
Notes:
1. Use block and gravel type sediment barrier when curb inlet is located in gently sloping street
segment, where water can pond and allow sediment to separate from runoff.
2. Barrier shall allow for overflow from severe storm event.
3. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be
removed from the traveled way immediately.
Back of sidewalk
Catch basin
Back of curb Curb inlet
Concrete block
2x4 Wood stud
Concrete block34 inch (20 mm)
Drain gravel
Wire screen or
filter fabric
3 4 inch (20 mm)
Drain gravel
Wire screen or
filter fabric
Ponding height
Overflow
2x4 Wood stud
(100x50 Timber stud)
Concrete block
Curb inlet
Catch basin
DEPARTMENT OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.10
Curb and Gutter Barrier
Revised September 2015
NOT TO SCALE
Plan View
Back of sidewalk
Runoff
Runoff Spillway
Burlap sacks to
overlap onto curb
Gravel filled sandbags
stacked tightly
Curb inlet
Catch basin
Back of curb
Notes:
1. Place curb type sediment barriers on gently sloping street segments, where water can
pond and allow sediment to separate from runoff.
2. Sandbags of either burlap or woven 'geotextile' fabric, are filled with gravel, layered
and packed tightly.
3. Leave a one sandbag gap in the top row to provide a spillway for overflow.
4. Inspect barriers and remove sediment after each storm event. Sediment and gravel
must be removed from the traveled way immediately.
Construction Stormwater Site Inspection Form
Page 1
Project Name Permit # 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:
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
Inspected
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
yes no n/a
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 road
way 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
Inspected
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
yes no n/a
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 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
Inspected
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
yes no n/a
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.
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
Construction Stormwater Site Inspection Form
Page 5
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
Attach additional page if needed
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: