HomeMy WebLinkAboutVarma Short Plat SWPPPConstruction Stormwater General Permit (CSWGP)
Stormwater Pollution Prevention Plan
(SWPPP)
for
Varma Short Plat
Prepared for:
The Washington State Department of Ecology
Northwest Regional Office
3190 160th Ave SE
Bellevue, WA 98008
SDP2017-02556
Permittee / Owner Developer Operator / Contractor
Kushal Varma
4159 NW Weekgate Ave
Portland, OR 97229
Kushal Varma
4159 NW Weekgate Ave
Portland, OR 97229
TBD
[Insert Project Site Location]
Certified Erosion and Sediment Control Lead (CESCL)
Name Organization Contact Phone Number
TBD TBD TBD
SWPPP Prepared By
Name Organization Contact Phone Number
Edward Mecum G2 Civil (425) 821-5038
SWPPP Preparation Date
2/25/2022
Project Construction Dates
Activity / Phase Start Date End Date
Site Grading TBD TBD
Table of Contents
PROJECT INFORMATION (1.0)..............................................................................................................4
CONSTRUCTION STORMWATER BEST MANAGEMENT PRACTICES (BMPS) (2.0)........................6
POLLUTION PREVENTION TEAM (3.0)...............................................................................................23
MONITORING AND SAMPLING REQUIREMENTS (4.0).....................................................................24
DISCHARGES TO 303(D) OR TOTAL MAXIMUM DAILY LOAD (TMDL) WATERBODIES (5.0).......27
REPORTING AND RECORD KEEPING (6.0) .......................................................................................28
List of Tables
1. Summary of Site Pollutant Constituents
2. Pollutants
3. pH-Modifying Sources
4. Management
5. Team Information
6. Turbidity Sampling Method
7. pH Sampling Method
List of Appendices
A. Site Map
B. BMP Detail
C. Site Inspection Form
D. CSWGP
E. Sediment Pond Design
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
Project Information (1.0)
Project/Site Name: Kushal Varma
Street/Location: 13016 156th Ave SE
City: Renton State: WA Zip code: 98059
Subdivision: N/A
Receiving waterbody: Cedar River
Existing Conditions (1.1)
Total acreage (including support activities such as off-site equipment staging yards, material
storage areas, borrow areas).
Total acreage: 3.22
Disturbed acreage: 3.22
Existing structures: Single Family Residence
Landscape topography: The existing topography of the construction area on the lot has slopes
which range between 0% to 2%.
Drainage patterns: Runoff from the eastern portion of the site sheet flows south and east into a
roadside ditch on the west side of 158th Ave SE and flows south through a series of ditches and
culverts. Runoff from the western portion of the site sheet flows south and west into a roadside
ditch on the east side of 156th Ave SE and also flows south through a series of ditches and
culverts. These two flow paths do not converge within a ¼ of a mile; therefore, the two separate
Natural Discharge Areas have been described and modeled as two separate Threshold
Discharge Areas. See full downstream analysis in Section III of this Technical Information
Report (TIR).
Existing Vegetation: Grass, lawn, vegetation, trees.
Critical Areas: According to COR Maps, and the Wetland and Stream Reconnaissance dated
January 29, 2020, no critical areas are located on the project site.
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.
Table 1 – Summary of Site Pollutant Constituents
Constituent
(Pollutant)Location Depth Concentration
Gasoline Construction Vehicles
Proposed Construction Activities (1.2)
Description of site development:
The project site is located at 13016 156th Ave SE in Renton, WA. The tax parcel number is
366450-0185 and 366450-0205. The site is 140,421 square-feet (3.22 acres) and currently
developed with a single-family residence on the far west side of parcel 366450-0205 accessed
from a gravel driveway on the east side of 156th Ave SE. North of the residence, the area
encompassing parcel 366450-0185 has been cleared and consists of open grass and a few
stockpiles of sand and gravel. To the east of the residence, the remainder of site is undeveloped
and consists of a mixed upland forest and brush patches.
The project proposes the development of nine (9) single-family lots within the 140,421 SF (3.22
Acres) parcel, as well as a 5.5-foot right-of-way dedication with frontage improvements along
156th Ave SE. A residential access street will traverse east to west across the site giving access
to each lot via paved driveways. Frontage improvements along 156th Ave SE and 158th Ave SE
will include the addition of a 5-foot sidewalk, 8-foot planter strip, as well as curb and gutter along
the edge of asphalt roadway. On the west side of the site, the residential access street will
include a 5-foot sidewalk, 8-foot planter strip as well as curb and gutter on both side of the
street. On the east side of the site, a 5-foot sidewalk, 8-foot planter strip as well as curb and
gutter will only be present on the south side of the street.
Description of construction activities
The area of disturbance will be cleared and graded prior to the start of construction. The
development of the site will include site grading and utilities installation. Utilities will include
stormwater, sanitary sewer, potable water, and all private utilities.
Description of site drainage:
Stormwater runoff from the proposed development of Lots 1-9 as well as the proposed road
improvements on 156th Ave SE, 158th Ave SE, and the Residential Access street will be managed
as follows:
Lots 1-9: Stormwater from impervious areas including rooftop and driveways on Lots 1 and
4 will be conveyed to Tract A, and into a wet vault followed by three detention tanks before
it is conveyed south and eventually released into the roadside ditch along the east side of
156th Ave SE. Stormwater from impervious areas including rooftop and driveways on Lots
2, 3, and 5-9 will be conveyed to Tract B, and into a combination wetvault/detention vault
before entering a new storm conveyance system on 158th Ave SE, and eventually released
into the ditch on the west side of 158th Ave SE. Where feasible, BMP’s satisfying Core
Requirement #9 will be used to the maximum extent feasible to mitigate other new runoff
created by the proposed single-family residence and other impervious surfaces on-site.
Basic dispersion will be used on some residences to mitigate stormwater from rooftop areas.
Residential Access Street: Stormwater from roadway improvements on the Residential
Access Street will be conveyed through the on-site storm system to the wetvault/detention
vault on Tract B.
156th Ave SE: Stormwater from the improved roadway north of the intersection of 156th Ave
SE and the Residential Access Street will flow into a series of 3 catch basins on the east
side of 156th Ave SE which convey the stormwater to a wet vault and detention tank facility
on Tract A. South of this intersection, stormwater will follow existing drainage patterns and
sheet flow into the ditch on the east side of 156th Ave SE.
158th Ave SE: Stormwater on 158th Ave SE will enter a series of catch basins and flow
south down the center of 158th Ave SE. At the intersection of 158th Ave SE and NE 2nd Pl,
the stormwater will enter the existing ditch on the west side of the road and follow existing
drainage patterns to the south.
Description of final stabilization:
Final stabilization will include revegetation and landscaping of exposed areas, as well as paving
of roads and sidewalks.
Contaminated Site Information:
There are no known contaminated soils on site.
Construction Stormwater Best Management Practices
(BMPs) (2.0)
The 12 Elements (2.1)
Element 1: Preserve Vegetation / Mark Clearing Limits (2.1.1)
The limits of clearing and grading will be marked in several ways around the site depending on
the location. Combination high visibility orange/silt fencing will be installed along clearing limits.
Several trees are scheduled to be retained on the site. Trees that are within the clearing limits
will need to be protected with a tree protection fence.
During the clearing effort, the topsoil and duff materials should be kept in a separate stockpile
for future use to help promote grass growth during project close out.
List and describe BMPs:
BMP C101: Preserving Natural Vegetation
BMP C102: Buffer Zones
BMP C103: High Visibility Fence
BMP C233: Silt Fence
Installation Schedules: Marking the clearing limits is one of the first things to be accomplished
on the construction site. Prior to any site clearing or grading, areas that are to remain
undisturbed during project construction shall be delineated. Once all plat construction is
complete the clearing limit BMP’s may be removed as approved by the City.
Inspection and Maintenance plan: The clearing limits should be observed daily and thoroughly
inspected weekly to ensure they are in place and functioning to protect areas that are not being
cleared. Any damaged or missing portions of the clearing limit BMP’s should be repaired or
replaced immediately.
Responsible Staff: CESCL
Element 2: Establish Construction Access (2.1.2)
This project will establish a stabilized construction entrance off of SE 304th Street and a 25’x50’
gravel parking area on site for construction vehicles. If construction vehicles are observed
tracking soil onto the roads, a wheel wash will be installed at the construction access.
List and describe BMPs:
BMP C105: Stabilized Construction Entrance
BMP C107: Construction Road/Parking Area Stabilization
Installation Schedules: A temporary stabilized construction entrance and construction parking
area shall be constructed on-site prior to initiating other construction activities unless the
existing driveway proves to be adequate. The initial construction entrance will be installed south
of the proposed garage.
Inspection and Maintenance plan: The construction entrance will be observed daily for any
deficiencies such as excess dirt or mud. Also, the public roads will be observed on a continual
basis during vehicle exiting to ensure no soil deposits are being tracked onto the roadway. If the
construction entrance proves inadequate to prevent soil from being deposited onto the roadway,
additional measures will be necessary, including street sweeping and the use of a wheel wash
for pervasive failures. Other stabilized areas will be inspected regularly, especially after large
storm events. Any damaged or missing portions of the site BMP’s should be repaired or
replaced immediately.
Responsible Staff: CESCL
Element 3: Control Flow Rates (2.1.3)
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: A wet vault is proposed in Tract A on the west side of the lot and a
detention/water quality system is proposed in Tract B on the east side of the lot.
Installation Schedules: TBD.
Inspection and Maintenance plan: TBD.
Responsible Staff: City of Renton.
Element 4: Install Sediment Controls (2.1.4)
Silt fence will be installed along the downstream perimeter of the construction limits to minimize
sediment discharges from the site.
List and describe BMPs:
BMP C233: Silt Fence
Installation Schedules: Implementation of sediment control BMPs is scheduled for the beginning
of the project. These BMPs shall be functional before other land disturbing activities take place.
The measures described above are required throughout construction.
Inspection and Maintenance plan: The sediment control facilities should be inspected on a
weekly basis to verify that the capacity has not diminished due to sedimentation in such a way
that the BMP loses efficiency. Any damaged or missing portions of the site BMPs should be
repaired or replaced immediately.
Responsible Staff: CESCL
Element 5: Stabilize Soils (2.1.5)
Soils on site will be stabilized as appropriate through a variety of methods. These BMPs will be
implemented when soil is to remain unworked or at the threat of rain throughout the project.
Stock piles will be covered with plastic sheeting unless an extended period of storage is
expected, in which case the stockpiles should be seeded and covered with mulch and an
erosion control net. Runoff from plastic sheeting will be directed to an acceptable discharge
location.
During the hot summer months, dust control is necessary. This is accomplished by applying
water to dry soils routinely. The water should not be applied in a way that creates runoff,
however.
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
East of the Cascade Mountains Crest, except the Central Basin*
Season Dates Number of Days Soils Can
be Left Exposed
During the Dry Season July 1 – September 30 10 days
During the Wet Season October 1 – June 30 5 days
The Central Basin*, East of the Cascade Mountain Crest
Season Dates Number of Days Soils Can
be Left Exposed
During the Dry Season July 1 – September 30 30 days
During the Wet Season October 1 – June 30 15 days
*Note: The Central Basin is defined as the portions of Eastern Washington with mean annual precipitation
of less than 12 inches.
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?
Yes No
List and describe BMPs:
BMP C120: Temporary and Permanent
Seeding BMP C121: Mulching
BMP C123: Plastic Covering
BMP C140: Dust Control
Installation Schedules: Soil Stabilization BMPs will be applied as deemed necessary. Exposed
areas should be evaluated and covered to prevent impacts to roadways, drainage ways, or
surface waters. Seeding shall be used throughout the project on disturbed areas that have
reached final grade or that will remain unworked for more than 30 days.
Inspection and Maintenance plan: Soil Stabilization BMPs should be reviewed daily and
thoroughly inspected weekly and after each rainfall event to ensure they are functioning
appropriately. All deficiencies shall be repaired or replaced in accordance with the number of
days exposed soils may be left exposed. Any damaged or missing portions of the site BMPs
should be repaired or replaced immediately.
Responsible Staff: CESCL
Element 6: Protect Slopes (2.1.6)
There are no existing steep slopes on the site, and no slopes are proposed to be constructed or
altered by the development.
Will steep slopes be present at the site during construction?
Yes No
List and describe BMPs: None
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
Element 7: Protect Drain Inlets (2.1.7)
Catch basin inserts will be installed on all on-site and downstream catch basins.
List and describe BMPs:
BMP C220: Inlet Protection
Installation Schedules: Storm drain inlets are to be installed prior to the start of construction for
all existing inlets. Constructed onsite catch basins will be protected prior to the first gravel lift.
Inspection and Maintenance plan: All facilities should be inspected weekly and after every
rainfall event. BMPs showing 1/3 of their capacity full of sediment should have the sediment
removed or the unit replaced. Any damaged or missing portions of the site BMPs should be
repaired or replaced immediately.
Responsible Staff: CESCL
Element 8: Stabilize Channels and Outlets (2.1.8)
A temporary interceptor swale with check dams/TSDs as described in detail in Element 3 has
been designed to intercept runoff from unprotected areas and direct it to the temporary
sediment pond. The design velocity of the swale is less than 2 f/s; therefore, stabilization via
seeding will be utilized. Please refer to the site plan in Appendix A and the Sediment Pond
Design Calculations in Appendix E for additional details.
List and describe BMPs:
BMP C120: Temporary and Permanent Seeding
BMP C207: Check Dams
BMP C208: Triangular Silt Dike (TSD)
BMP C209: Outlet Protection
Installation Schedules: Stabilization BMPs are to be implemented after temporary channels are
constructed. Channel lining shall be used if other measures prove insufficient for stabilization.
Inspection and Maintenance plan: BMPs shall be monitored for performance and sediment
accumulation during and after each runoff event. Sediment shall be removed from check dams
when it reaches on half the sump depth. Any damaged or missing portions of the site BMPs
should be repaired or replaced immediately.
Responsible Staff: CESCL
Element 9: Control Pollutants (2.1.9)
The following pollutants are anticipated to be present on-site:
Table 2 – Pollutants
Pollutant (and source, if applicable)
Gasoline in vehicles
Concrete poured in place
There are no known pollutants contained on the existing site. During construction, the contractor
will need to conduct maintenance, fueling, and repair of heavy equipment and vehicles at the
designated contractor parking area, as spills of hazardous materials could result in an
environmental event.
If a wheel wash is incorporated into the protection plan, the contractor will discharge wheel
wash wastewater to a separate on-site treatment system that prevents discharge to surface
water, such as closed-loop recirculation or upland land application, or to the sanitary sewer, with
local sewer district approval.
Concrete will be handled in ways to eliminate concrete, concrete process water, and concrete
slurry from entering waters of the state.
List and describe BMPs:
BMP C151: Concrete Handling
BMP C153: Material Delivery, Storage and Containment
BMP C154: Concrete Washout Area
BMP C251: Construction Stormwater Filtration
Installation Schedules: BMPs will be implemented at the beginning of construction and as
needed throughout the project. Concrete washout BMPs shall be in place prior to the
commencement of concrete work.
Inspection and Maintenance plan: Inspection of the concrete washout area should be done
weekly and prior to expected concrete pours. Washout facilities must be cleaned, or new
facilities must be constructed and ready for use one the washout is 75% full. Secondary
containment facilities should be inspected daily and repaired or replaced as necessary.
Contaminated surfaces shall be cleaned immediately following any discharge or spill incident.
Any damaged or missing portions of the site BMPs should be repaired or replaced immediately.
Responsible Staff: CESCL
Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site?
Yes No
List and describe BMPs:
BMP C153: Material Delivery, Storage and Containment
Installation Schedules: Containment of hazardous materials will be conducted throughout the
duration of construction.
Inspection and Maintenance plan: Containment facilities should be inspected daily and repaired
or replaced as necessary. Material storage areas shall be kept clean, organized and equipped
with an ample supply of appropriate spill clean-up material. Contaminated surfaces shall be
cleaned immediately following any discharge or spill incident. Any damaged or missing portions
of the site BMPs should be repaired or replaced immediately.
Responsible Staff: CESCL
Will wheel wash or tire bath system BMPs be used during construction?
Yes No
List and describe BMPs:
BMP C106: Wheel Wash
Installation Schedules: Wheel wash systems will be installed if deemed necessary by the
contractor when the stabilized construction entrance is not preventing sediment from being
tracked onto pavement.
Inspection and Maintenance plan: Wheel wash systems will be inspected weekly and repaired
as necessary. Wash water should be changed a minimum of once per day.
Responsible Staff: CESCL
Will pH-modifying sources be present on-site?
Yes No
Table 3 – pH-Modifying Sources
None
X Bulk cement
Cement kiln dust
Fly ash
Other cementitious materials
X New concrete washing or curing waters
Waste streams generated from concrete grinding and sawing
Exposed aggregate processes
Dewatering concrete vaults
X Concrete pumping and mixer washout waters
Recycled concrete
Other (i.e. calcium lignosulfate) [please describe]
During this construction activity, the pH levels of stormwater runoff must be monitored. If pH
levels exceed 8.5, the level will need to be corrected. The use of CO2 per WDOE standards will
rapidly neutralize the water and make it suitable for discharge.
List and describe BMPs:
BMP C252: Treating and Disposing of High pH Water
Installation Schedules: pH neutralization using CO2 will be implemented as necessary to correct
pH levels in excess of 8.5.
Inspection and Maintenance plan: Operators will keep written records related to treatment as
detailed in the Stormwater Management Manual for Western Washington. A copy of this record
should be given to the client/contractor who should retain the record for three years.
Responsible Staff: CESCL
Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches,
streets, or streams. Excess concrete must not be dumped on-site, except in designated
concrete washout areas with appropriate BMPs installed.
Element 10: Control Dewatering (2.1.10)
Dewatering is not anticipated.
List and describe BMPs:
BMP C220: Inlet Protection
Installation Schedules: Storm drain inlets are to be installed prior to the start of construction and
dewatering for all existing inlets.
Inspection and Maintenance plan: All facilities should be inspected weekly and after every
rainfall event. BMPs showing 1/3 of their capacity full of sediment should have the sediment
removed or the unit replaced. Any damaged or missing portions of the site BMPs should be
repaired or replaced immediately.
Responsible Staff: CESCL
Element 11: Maintain BMPs (2.1.11)
All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained
and repaired as needed to ensure continued performance of their intended function.
Maintenance and repair shall be conducted in accordance with each particular BMP
specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW).
Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar
week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the
site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to
once every calendar month.
All temporary ESC BMPs shall be removed within 30 days after final site stabilization is
achieved or after the temporary BMPs are no longer needed.
Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal
of either BMPs or vegetation shall be permanently stabilized.
Additionally, protection must be provided for all BMPs installed for the permanent control of
stormwater from sediment and compaction. BMPs that are to remain in place following
completion of construction shall be examined and restored to full operating condition. If
sediment enters these BMPs during construction, the sediment shall be removed and the facility
shall be returned to conditions specified in the construction documents.
List and describe BMPs:
BMP C150: Materials on Hand
BMP C160: Certified Erosion and Sediment Control
Lead Responsible Staff: CESCL
Element 12: Manage the Project (2.1.12)
The project will be managed based on the following principles:
Projects will be phased to the maximum extent practicable and seasonal work limitations
will be taken into account.
Inspection and monitoring:
o Inspection, maintenance and repair of all BMPs will occur as needed to ensure
performance of their intended function.
o Site inspections and monitoring will be conducted in accordance with Special
Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map.
Sampling station(s) are located in accordance with applicable requirements of
the CSWGP.
Maintain an updated SWPPP.
o The SWPPP will be updated, maintained, and implemented in accordance with
Special Conditions S3, S4, and S9 of the CSWGP.
As site work progresses the SWPPP will be modified routinely to reflect changing site
conditions. The SWPPP will be reviewed monthly to ensure the content is current.
Table 4 – Management
X Design the project to fit the existing topography, soils, and drainage patterns
X Emphasize erosion control rather than sediment control
Minimize the extent and duration of the area exposed
X Keep runoff velocities low
X Retain sediment on-site
X Thoroughly monitor site and maintain all ESC measures
Schedule major earthwork during the dry season
Other (please describe)
Element 13: Protect Low Impact Development (LID) BMPs (2.1.13)
The proposed project will not incorporate LID BMPs. No protection is required for this BMP.
Pollution Prevention Team (3.0)
Table 5 – Team Information
Title Name(s)Phone Number
Certified Erosion and
Sediment Control Lead
(CESCL)
TBD TBD
Resident Engineer Edward Mecum (425) 364-5285
Emergency Ecology
Contact
TBD TBD
Emergency Permittee/
Owner Contact
Kushal Varma (949) 838-6057
Non-Emergency Owner
Contact
Kushal Varma (949) 838-6057
Monitoring Personnel TBD TBD
Ecology Regional Office Northwest (425) 649-7000
Monitoring and Sampling Requirements (4.0)
Monitoring includes visual inspection, sampling for water quality parameters of concern, and
documentation of the inspection and sampling findings in a site log book. A site log book will be
maintained for all on-site construction activities and will include:
A record of the implementation of the SWPPP and other permit requirements
Site inspections
Stormwater sampling data
The site log book must be maintained on-site within reasonable access to the site and be made
available upon request to Ecology or the local jurisdiction.
Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See
CSWGP Special Condition S8 and Section 5 of this template.
Complete the following paragraph for sites that discharge to impaired waterbodies for fine
sediment, turbidity, phosphorus, or pH:
Site Inspection (4.1)
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.
Stormwater Quality Sampling (4.2)
Turbidity Sampling (4.2.1)
Requirements include calibrated turbidity meter or transparency tube to sample site discharges
for compliance with the CSWGP. Sampling will be conducted at all discharge points at least
once per calendar week.
Method for sampling turbidity:
Table 8 – Turbidity Sampling Method
Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size)
X Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size)
The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency
less than 33 centimeters.
If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to
or greater than 6 cm, the following steps will be conducted:
1. Review the SWPPP for compliance with Special Condition S9. Make appropriate
revisions within 7 days of the date the discharge exceeded the benchmark.
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.
https://www.ecology.wa.gov/About-us/Get-involved/Report-an-environmental-issue
Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima):
(509) 575-2490
Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant,
Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400
Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish,
Whatcom): (425) 649-7000
Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis,
Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300
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.
pH Sampling (4.2.2)
pH monitoring is required for “Significant concrete work” (i.e. greater than 1000 cubic yards
poured concrete or recycled concrete over the life of the project).The use of 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:
Table 8 – pH Sampling Method
pH meter
X pH test kit
Wide range pH indicator paper
Discharges to 303(d) or Total Maximum Daily Load (TMDL)
Waterbodies (5.0)
303(d) Listed Waterbodies (5.1)
Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH?
Yes No
List the impairment(s): N/A
List and describe BMPs: N/A
TMDL Waterbodies (5.2)
No known waste load allocation for CWSGP discharges.
Reporting and Record Keeping (6.0)
Record Keeping (6.1)
Site Log Book (6.1.1)
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
Records Retention (6.1.2)
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.
Updating the SWPPP (6.1.3)
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.
Reporting (6.2)
Discharge Monitoring Reports (6.2.1)
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.
Notification of Noncompliance (6.2.2)
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.
Appendix/Glossary
A. Site Map
The site map must meet the requirements of Special Condition S9.E of the CSWGP
B. BMP Detail
Insert BMPs specification sheets here.
Download BMPs from the Ecology Construction Stormwater website at:
https://www.ecology.wa.gov/Regulations-Permits/Guidance-technical-
assistance/Stormwater-permittee-guidance-resources/Stormwater-manuals
C. Correspondence
Ecology
EPA
Local Government
D. Site Inspection Form
Create your own or download Ecology’s template:
https://www.ecology.wa.gov/Regulations-Permits/Permits-certifications/Stormwater-
general-permits/Construction-stormwater-permit
E. Construction Stormwater General Permit (CSWGP)
Download CSWGP: https://www.ecology.wa.gov/Regulations-Permits/Permits-
certifications/Stormwater-general-permits/Construction-stormwater-permit
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