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Construction Stormwater General Permit
Stormwater Pollution Prevention Plan
(SWPPP)
for
Grant Place Townhomes
Permit # PRE23-000015
Prepared for:
The Washington State Department of Ecology
Northwest Region
Permittee / Owner Developer Operator / Contractor
Satwant Singh
Skyline Properties, Inc.
50 116th Ave. SE
Ste. 120
Bellevue, WA 98004
Satwant Singh
Skyline Properties, Inc.
50 116th Ave. SE
Ste. 120
Bellevue, WA 98004
TBD
Shoreline, WA
Certified Erosion and Sediment Control Lead (CESCL)
Name Organization Contact Phone Number
TBD TBD TBD
SWPPP Prepared By
Name Organization Contact Phone Number
Rachel Elliott, EIT Furr Engineering, PLLC (404) 345-4400
SWPPP Preparation Date
March 30, 2023
Project Construction Dates
Activity / Phase Start Date End Date
Project construction June 1st, 2023 Sept. 30th, 2024
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Table of Contents
1 Project Information .............................................................................................................. 4
1.1 Existing Conditions ...................................................................................................... 4
1.2 Proposed Construction Activities .................................................................................. 5
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 .................................................................... 8
2.1.5 Element 5: Stabilize Soils ..................................................................................... 9
2.1.6 Element 6: Protect Slopes....................................................................................10
2.1.7 Element 7: Protect Drain Inlets ............................................................................11
2.1.8 Element 8: Stabilize Channels and Outlets ..........................................................12
2.1.9 Element 9: Control Pollutants ...............................................................................13
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 .................................20
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 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies .........................24
5.1 303(d) Listed Waterbodies ..........................................................................................24
5.2 TMDL Waterbodies .....................................................................................................24
6 Reporting and Record Keeping ..........................................................................................25
6.1 Record Keeping ..........................................................................................................25
6.1.1 Site Log Book ......................................................................................................25
6.1.2 Records Retention ...............................................................................................25
6.1.3 Updating the SWPPP ...........................................................................................25
6.2 Reporting ....................................................................................................................26
6.2.1 Discharge Monitoring Reports ..............................................................................26
6.2.2 Notification of Noncompliance ..............................................................................26
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List of Tables
Table 1 – Summary of Site Pollutant Constituents ................................................................ 5
Table 2 – Pollutants ................................................................................................................13
Table 3 – pH-Modifying Sources ............................................................................................14
Table 4 – Dewatering BMPs ....................................................................................................16
Table 5 – Management ............................................................................................................18
Table 6 – BMP Implementation Schedule ..............................................................................19
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
C. Correspondence
D. Site Inspection Form
E. Construction Stormwater General Permit (CSWGP)
F. 303 (d) List Waterbodies/TMDL Waterbodies Information
G. Contaminated Site Information
H. Engineering Calculations
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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: Grant Place Townhomes
Street/Location: 1600 Grant Ave
City: Renton State: WA Zip code: 98055
Subdivision:
Receiving waterbody: Black River
1.1 Existing Conditions
This project proposes the construction of eight townhouse buildings on a single 92,828 sf (2.131
ac) parcel (no. 202305-9052) located at 1600 Grant Ave. S, Renton, WA 98055. This project is
the continuation of an expired plat (civil permit no. U16004475); currently, the site is partially
developed with several constructed buildings, building foundations, utilities, and rough-graded
alley.
Stormwater onsite is collected into a combined detention/wetvault, designed by others, which
discharges through a Contech StormFilter manhole and into the municipal storm system within
Grant Ave. Low Impact Development (LID) BMPs are generally infeasible onsite due to unsuitable
soils, high/perched groundwater, and the amount of completed construction onsite. A letter from
a licensed geotechnical engineer has been added to the 2005 geotechnical investigation to
confirm site conditions and to approve construction to continue as proposed.
Total acreage: 2.192 ac
Disturbed acreage: 2.192 ac
Existing structures: Partially-constructed townhouses, rough grading
Landscape Topography: Slopes 5 – 15%
Drainage patterns: Sheet-flows east to west, enters storm system
Existing Vegetation: N/A – project partially constructed
Critical Areas (wetlands, streams,
high erosion risk, steep or difficult to
stabilize slopes):
N/A
List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the
receiving waterbody: N/A
Table 1 includes a list of suspected and/or known contaminants associated with the construction
activity.
List all known or suspected contaminants associated with this site in Table 1. Include
contaminants previously remediated.
There are no known contaminants within the soil at this location.
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Table 1 – Summary of Site Pollutant Constituents
Constituent (Pollutant) Location Depth Concentration
None known to exist on site
1.2 Proposed Construction Activities
The project proposes the construction of a single-family residence, to be accessed by a new
asphalt and concrete driveway from Mirrormont Blvd, and new retaining walls. Development will
also include a new septic system, permitted separately. Runoff from impervious surfaces onsite
will be collected into a detention vault, which will discharge into an existing vegetated street on
the north side of Mirrormont.
Construction Activities:
Fine-grade site; alley construction and paving; complete building construction; landscaping and
walkway construction.
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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
The site will be delineated by silt fence and high visibility fencing.
List and describe BMPs:
BMP C101: Preserving Natural Vegetation
BMP C102: Buffer Zone
BMP C103: High Visibility Plastic or Metal Fence
BMP C233: Silt Fence
Installation Schedules: once prior to construction
Inspection and Maintenance plan: Weekly and daily during storm events
Responsible Staff: TBD
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2.1.2 Element 2: Establish Construction Access
The existing gravel driveway shall be used as construction access.
Street washing is not permitted, even after shoveling or sweeping.
During construction, if material is being deposited on off-site streets, consider implementing the
following:
1. Regenerative-type vacuum sweepers and repeated or continuous sweeping.
2. Wheel wash (or an improved wheel wash if one already exists).
3. Special site procedures and provisions (such as transferring haul-outs to trucks that travel
only on paved and maintained surfaces in the site).
4. Suspension of work until dry weather.
List and describe BMPs:
BMP C105: Stabilized Construction Entrance / Exit. Installed per Plan
BMP C106: Wheel Wash
BMP C107: Construction Road/Parking Area Stabilization
Inspection and Maintenance plan: Weekly
It will be the responsibility to clean all roadway surfaces using regenerative vacuum sweepers.
Installation Schedules: as needed.
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:
Installation Schedules: Once at the beginning of the project.
Inspection and Maintenance plan:
Weekly and after every storm event. Sediment shall be removed when it reaches 1ft above the
bottom.
Responsible Staff: TBD
2.1.4 Element 4: Install Sediment Controls
Silt fence will be installed downstream along the determined clearing limits.
List and describe BMPs:
BMP C233: Silt Fence
Installation Schedules: once prior to construction activities
Inspection and Maintenance plan: Weekly and daily during storm events
Responsible Staff: TBD
If the standards are not being met, additional BMPs (including site-specific designs) shall be
implemented. If additional BMPs are not implemented or are not successful, work may be
suspended until the City approves a new SWPPP (see Vol. II: 2.3).
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2.1.5 Element 5: Stabilize Soils
All unworked exposed soil will be covered by mulching, plastic covering or permanently
vegetated. It is the intent to have all hardscape constructed early in the project.
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: 6/1/2023 End date: 6/1/2024
Will you construct during the wet season?
Yes No
It is anticipated that any construction during the wet season will be confined to building
construction (framing, plumbing, electrical, etc.) and interior finishing of the building only. All
proposed hardscapes will be constructed prior to the wet season and all landscaping will be
planted and mulched.
List and describe BMPs:
BMP C120: Temporary and Permanent Seeding
BMP C121: Mulching
BMP C125: Topsoiling/Composting - as a requirement to provide on-site stormwater
management to implement BMP T5.13: Post Construction Soil Quality and Depth - Installed
per plan
BMP C123: Plastic Covering to be used on stockpiles and cut slopes
BMP C150: Materials on Hand - in the event that additional TESC materials are necessary
during emergency situations.
Installation Schedules: As soon as soils get exposed
Inspection and Maintenance plan: Weekly and daily during storm events
Responsible Staff: TBD
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2.1.6 Element 6: Protect Slopes
Tributary areas adjacent to cut slopes are small and runoff can be considered negligible
because they are considered flat and vegetated. Cut slopes on the order of 8ft and fill slopes on
the order of 3ft are expected during foundation construction. These slopes should be covered
by plastic until the foundation walls are set and the foundations should be immediately
backfilled. The exposed soil must be covered with mulch.
Clearing/grading work shall comply with the Stormwater Manual, geotechnical
recommendations, SEPA (State Environmental Policy Act) conditions, and other applicable
regulations and standards. These project-specific requirements are in addition to and take
priority over general standards.
Will steep slopes be present at the site during construction?
Yes No
List and describe BMPs:
BMP C121: Mulching
BMP C123: Plastic Covering to be used on stockpiles and cut slopes
Installation Schedules: when the cuts are made
Inspection and Maintenance plan: Daily
Responsible Staff: TBD
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2.1.7 Element 7: Protect Drain Inlets
There are no off-site catch basins or drain inlets near this project site.
List and describe BMPs:
Installation Schedules: Once prior to construction activities
Inspection and Maintenance plan: Weekly and during storm events. Sediment buildup must be
removed when the device is filled by one third (1/3).
Responsible Staff: TBD
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2.1.8 Element 8: Stabilize Channels and Outlets
Temporary conveyance channels shall be stabilized for the 10-year, 24-hour frequency storm,
and assuming full build out of tributary area(s).
List and describe BMPs:
BMP C122: Nets and Blankets
BMP C202: Rip Rap Channel Lining
BMP C207: Check Dams
Installation Schedules: as needed.
Inspection and Maintenance plan: as needed.
Responsible Staff: TBD
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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)
Concrete from foundation construction
Waste material/demolition debris
All pollutants, including waste materials and demolition debris, that occur onsite shall 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. Dust will be controlled and is in compliance with the Puget
Sound Clean Air Agency and Work in Critical Areas conforms to requirements of the City’s
Critical Areas Ordinance (CAO). If required, BMPs to be implemented to control specific
sources of pollutants are discussed below.
List and describe BMPs:
BMP C151: Concrete Handling
BMP C152: Saw cutting and Surfacing Pollution Prevention
BMP C153: Material Delivery, Storage and containment
Installation Schedules: Prior to construction and during foundation construction
Inspection and Maintenance plan: Weekly and during storm events
Responsible Staff: TBD
Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site?
Yes No
List and describe BMPs:
Installation Schedules:
Inspection and Maintenance plan:
Responsible Staff:
Will wheel wash or tire bath system BMPs be used during construction?
Yes No
If yes, provide disposal methods for wastewater generated by BMPs.
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If discharging to the sanitary sewer, include the approval letter from your local sewer district
under Correspondence in Appendix C.
List and describe BMPs:
Installation Schedules:
Inspection and Maintenance plan:
Responsible Staff:
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: ]
Construction concrete washout is planned to be done onsite using an eco-pan type system. On
a weekly basis the eco pans will be disposed of offsite at an approved facility.
List and describe BMPs:
BMP C151: Concrete Handling
BMP C152: Saw cutting and Surfacing Pollution Prevention
BMP C153: Material Delivery, Storage and containment
Installation Schedules: Throughout the project
Inspection and Maintenance plan: Inspection and Maintenance plan: Inspect weekly and
dispose of eco pans weekly or more frequently. Dispose to an approved facility
Responsible Staff: TBD
Adjust pH of stormwater if outside the range of 6.5 to 8.5 su.
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Obtain written approval from Ecology and the City of Sammamish before using chemical
treatment with the exception of CO2 or dry ice to modify pH.
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
If yes, provide BMPs to contain the wastewater during infiltration.
Prior to infiltration, water from water- only based shaft drilling that comes into contact with curing
concrete must be neutralized until pH is in the range of 6.5 to 8.5 (su).
List and describe BMPs:
Installation Schedules:
Inspection and Maintenance plan:
Responsible Staff:
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2.1.10 Element 10: Control Dewatering
Dewatering is not anticipated for this project.
Check treatment of disposal option for dewatering water, if applicable:
Table 4 – Dewatering BMPs
Infiltration
Transport off-site in a vehicle (vacuum truck for legal disposal)
Ecology-approved on-site chemical treatment or other suitable treatment technologies
Sanitary or combined sewer discharge with local sewer district approval (last resort)
Use of sedimentation bag with discharge to ditch or swale (small volumes of localized
dewatering)
List and describe BMPs:
Installation Schedules:
Inspection and Maintenance plan:
Responsible Staff:
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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.
For CESCL requirements, and Rainy Season Requirements and Seasonal Suspension
Plan, refer to EDM Chapter 22, Stormwater Pollution Prevention Plan.
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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Table 6 – BMP Implementation Schedule
Phase of Construction
Project
Stormwater BMPs Date Wet/Dry
Season
Pre construction Establish Clearing Limits, Silt
Fence, Construction Entrance,
High Visibility Fence
6/1/2023
Dry
Export Dust Control to include sprinkling
water on soil and vacuum or wet
sweep fine dirt and skid control
materials from paved roads soon
after rain events or when needed.
6/14/2023 Dry
Building foundation and
vault
BMP C151: Concrete Handling,
BMP C152: Saw cutting and
Surfacing Pollution Prevention,
BMP C153: Material Delivery,
Storage and containment
6/14/2023 Dry
Site Grading utility
trenching
Maintain installed BMPS and
Dust Control
8/14/2023 Dry
Driveway and Sidewalk
construction
BMP C151: Concrete Handling,
BMP C152: Saw cutting and
Surfacing Pollution Prevention,
BMP C153: Material Delivery,
Storage and containment
8/14/2023 Dry
Building Construction 8/14/2023 Dry
Landscaping BMP C120: Temporary and
Permanent Seeding
BMP C125:
Topsoiling/Composting - as a
requirement to provide on-site
stormwater management to
implement BMP T5.13: Post
Construction Soil Quality and
Depth - Installed per plan
BMP C150: Materials on Hand -
in the event that additional TESC
materials are necessary during
emergency situations.
9/25/2023 Dry
Completed Project Site stabilized during building
construction
5/1/2024 Dry
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2.1.13 Element 13: Protect Low Impact Development (LID) BMPs
None.
3 Pollution Prevention Team
Table 7 – Team Information
Title Name(s) Phone Number
Certified Erosion and
Sediment Control Lead
(CESCL)
TBD TBD
Resident Engineer Dean A. Furr, P.E., CESCL 206.890.8291
Emergency Ecology
Contact
Report A Spill 425.649.7000
Emergency Permittee/
Owner Contact
Satwant Singh
Non-Emergency Owner
Contact
Satwant Singh
Monitoring Personnel TBD
Ecology Regional Office Northwest Regional Office 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
Create your own Site Inspection Form or use the Construction Stormwater Site Inspection Form
found on Ecology’s website.
http://www.ecy.wa.gov/programs/wq/stormwater/construction/index.html
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.
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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.
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.
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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 Discharges to 303(d) or Total Maximum Daily Load (TMDL)
Waterbodies
5.1 303(d) Listed Waterbodies
Circle the applicable answer, if necessary:
Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH?
Yes No
List the impairment(s):
If yes, discharges must comply with applicable effluent limitations in S8.C and S8.D of the
CSWGP.
5.2 TMDL Waterbodies
Waste Load Allocation for CWSGP discharges:
Describe the method(s) for TMDL compliance:
List and describe BMPs:
Discharges to TMDL receiving waterbodies will meet in-stream water quality criteria at the point
of discharge.
The Construction Stormwater General Permit Proposed New Discharge to an Impaired Water
Body form is included in Appendix F.
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6 Reporting and Record Keeping
6.1 Record Keeping
This section does not need to be filled out. It is a list of reminders for the permittee.
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.
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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.
To sign up for WQWebDMR go to:
http://www.ecy.wa.gov/programs/wq/permits/paris/webdmr.html
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.
Specific information to be included in the noncompliance report is found in Special Condition
S5.F.3 of the CSWGP.
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
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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
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B. BMP Detail
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C. Correspondence
Ecology
EPA
Local Government
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D. Site Inspection Form
Create your own or download Ecology’s template:
http://www.ecy.wa.gov/programs/wq/stormwater/construction/index.html
Select Permit, Forms and Application to find the link to the Construction Stormwater
Site Inspection Form.
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E. Construction Stormwater General Permit (CSWGP)
Download the CSWGP:
http://www.ecy.wa.gov/programs/wq/stormwater/construction/index.html
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F. 303(d) List Waterbodies / TMDL Waterbodies Information
Proposed New Discharge to an Impaired Water Body form
SWPPP Addendum addressing impairment
G. Contaminated Site Information
Administrative Order
Sanitary Discharge Permit
Soil Management Plan
Soil and Groundwater Reports
Maps and Figures Depicting Contamination
H. Engineering Calculations
The site proposes to use the detention vault for
construction stormwater mitigation and
sediment trap calculations are not required.
Sediment Traps
SA= FS (Q₂/ Vs) (Q₂)
FS= 2 Factor of Safety
Vs 0.00096 ft/sec Settling Velocity
Q2 15-min Peak from
WWHM2012
WWHM Input
Landcover Basin A
Type (AC)
Imp. Area
Grass
Total Area
Soil Type = Till
Used 15 min. Time series
Results
Basin A
Q10 (cfs)
SA REQD (ft²)