HomeMy WebLinkAboutTIR-4114
TECHNICAL INFORMATION REPORT
Brown Bear Car Wash
77 Rainier Avenue South
Renton, Washington
City of Renton File No. TBD
Prepared for:
Car Wash Enterprises, Inc.
3977 Leary Way N.W.
Seattle, WA
Revised: March 19, 2020
January 8, 2020
Our Job No. 20696
03/19/2020
Scott Warlick 7/15/2020
SURFACE WATER UTILITY
jfarah 07/15/2020
Technical Information Report Barghausen Consulting Engineers, Inc. Brown Bear Car Wash Renton, Washington Our Job No. 20696
20696.003-TIR.doc
TABLE OF CONTENTS
1.0 PROJECT OVERVIEW
Figure 1 - Vicinity Map
Figure 2 - Assessor Map
Figure 3 - FEMA Map
Figure 4 - Soil Survey Map
Figure 5 - Sensitive Areas Map
Figure 6 - Drainage Review Flow Chart
Figure 7 - TIR Worksheet
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
2.1 Analysis of the Core Requirements
2.2 Analysis of the Special Requirements
3.0 OFF-SITE ANALYSIS
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
4.1 Existing Site Hydrology
4.2 Developed Site Hydrology
4.3 Performance Standards
4.4 Flow Control System
4.5 Water Quality System
4.6 On-site BMPs
Figure 8 - Existing Conditions Map
Figure 9 - Proposed Conditions Map
Figure 10 - Oil/Water Separator Calculations
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
6.0 SPECIAL REPORTS AND STUDIES
6.1 Geologic Hazard Area Report
7.0 OTHER PERMITS
20696.003-TIR.doc
8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (CSWPP) ANALYSIS
AND DESIGN
9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
10.0 OPERATIONS AND MAINTENANCE MANUAL
Tab 1.0
20696.003-TIR.doc
1.0 PROJECT OVERVIEW
The proposed project site is located within a portion of Section 18, Township 23 North, Range 5
East of the Willamette Meridian. More specifically, the site is located at 77 Rainier Avenue South.
The site is made up of one (1) Tax Parcel No. 182305-9131. See Figure 1 for the Vicinity Map in
this section for the location of the proposed project site.
The existing 21,913 square-foot site consists of an existing 1,836 square-foot car wash structure,
an existing gas station with canopy, asphalt and concrete pavement, and landscaping. The
proposed improvements include the removal of the existing gas station and appurtenances, the
construction of a new auto sentry pay station, which includes a new canopy, new landscaping, and
relocation of the dumpster enclosure, and the installation of an oil/water separator to treat existing
runoff generated from the site. The total onsite and offsite improvements proposed 4,215 square
feet of replaced impervious surface as defined in the 2017 City of Renton Surface Water Design
Manual (SWDM).
Moreover, it is assumed that the portion of the site that includes the removal of the existing
underground storage tanks is not considered as a target surface as it falls under the definition for
utility/maintenance project. Per the definition of 'Replaced Impervious Surface' mentioned in the
2017 City of Renton SWDM, "hard surfaces proposed for the sole purpose of installing utilities or
performing maintenance on underground facilities, and hard surfaces that are proposed to be
constructed without the removal of the base course or bare soil, are not considered as such
(Replaced Impervious Surface)". The total impervious surfaces within the utility/maintenance is
approximately 1,608 square feet.
The total land disturbing area of the redevelopment is 5,823 square feet.
The site is relatively level with a rockery wall ranging from about 1 and a half to 4 feet tall. It is
located along the western property line and is the toe of the off-site east-facing slope. The project
intends to be completed with minimal modifications to the existing drainage network on-site. The
developed condition will rely on existing storm and sewer conveyance systems to meet the Core
and Special Requirements and satisfy the Full Drainage Review as specified in the 2017 City of
Renton Surface Design Manual and the City of Renton Municipal Code 4-6-030. Please See Figure
6 for the Flow Chart Determining the review type. The TIR worksheet is provided as Figure 7.
Figure 1
Vicinity Map
Horizontal:
Scale:
Vertical:
For:
Title:
VICINITY MAP
Job Number
N.T.S.N/A 20696
DATE: 12/18/19
Brown Bear Car Wash
77 Rainier Avenue South
Renton, Washington
P:\20000s\20696\exhibit\graphics\20696 vmap.cdr
REFERENCE: Rand McNally (2019)
SITE
Figure 2
Assessor Map
Horizontal:
Scale:
Vertical:
For:
Title:
ASSESSOR MAP
Job Number
N.T.S.N/A 20696
DATE: 12/18/19
Brown Bear Car Wash
77 Rainier Avenue South
Renton, Washington
P:\20000s\20696\exhibit\graphics\20696 amap.cdr
SITE
REFERENCE: King County Department of Assessments (Aug. 2018)
Figure 3
FEMA Map
Horizontal:
Scale:
Vertical:
For:
Title:
FEMA MAP
Job Number
N.T.S.N/A 20696
DATE: 12/18/19
Brown Bear Car Wash
77 Rainier Avenue South
Renton, Washington
P:\20000s\20696\exhibit\graphics\20696 fema.cdr
REFERENCE: Federal Emergency Management Agency (Portion of Map 53033C0977 F, May 1995)
Areas determined to be outside 500-year
floodplain.
ZONE X
OTHER AREAS
LEGEND
SITE
Figure 4
Soil Survey Map
Horizontal:
Scale:
Vertical:
For:
Title:
SOIL SURVEY MAP
Job Number
N.T.S.N/A 20696
DATE: 12/18/19
Brown Bear Car Wash
77 Rainier Avenue South
Renton, Washington
P:\20000s\20696\exhibit\graphics\20696 soil.cdr
HSG
B
-
REFERENCE: USDA, Natural Resources Conservation Service
LEGEND:
5020 = Beausite-Alderwood-Urban land complex, 12-35% slopes
SITE
Ur = Urban land
Figure 5
Sensitive Areas
Map
Horizontal:
Scale:
Vertical:
For:
Title:
SENSITIVE AREAS
MAP
Job Number
N.T.S.N/A 20696
DATE: 12/18/19
Brown Bear Car Wash
77 Rainier Avenue South
Renton, Washington
P:\20000s\20696\exhibit\graphics\20696 sens.cdr
SITE
REFERENCE: City of Renton GIS (2019)
Figure 6
Drainage Review
Flow Chart
SECTION 1.1 DRAINAGE REVIEW
12/12/2016 2017 City of Renton Surface Water Design Manual 1-14
FIGURE 1.1.2.A FLOW CHART FOR DETERMINING TYPE OF DRAINAGE REVIEW REQUIRED
Figure 7
TIR Worksheet
CITY OF RENTON SURFACE WATER DESIGN MANUAL
2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1
REFERENCE 8-A
TECHNICAL INFORMATION REPORT (TIR)
WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Owner _____________________________
Phone ___________________________________
Address __________________________________
_________________________________________
Project Engineer ___________________________
Company _________________________________
Phone ___________________________________
Project Name __________________________
CED Permit # ________________________
Location Township ________________
Range __________________
Section _________________
Site Address __________________________
_____________________________________
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
Land Use (e.g., Subdivision / Short Subd.)
Building (e.g., M/F / Commercial / SFR)
Grading
Right-of-Way Use
Other _______________________
DFW HPA
COE 404
DOE Dam Safety
FEMA Floodplain
COE Wetlands
Other ________
Shoreline Management
Structural Rockery/Vault/_____
ESA Section 7
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review
(check one):
Date (include revision
dates):
Date of Final:
Full
Targeted
Simplified
Large Project
Directed
____________________________________
__________________
Plan Type (check
one):
Date (include revision
dates):
Date of Final:
Full
Modified
Simplified
____________________________________
__________________
Car Wash Enterprises, Inc.
3977 Leary Way N.W.
Seattle, WA 98107
(206) 774-3765
Anthony E. Merlino
Barghausen Consulting Engineers, Inc.
(425) 251-6222 Ext. 1065
Brown Bear Facility 1008
PR19-000396
77 Rainier Avenue South
18
05
23
Renton, Washington 98057
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2
Part 6 SWDM ADJUSTMENT APPROVALS
Type (circle one): Standard / Blanket
Description: (include conditions in TIR Section 2)
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
Approved Adjustment No. ______________________ Date of Approval: _______________________
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / No
Start Date: _______________________
Completion Date: _______________________
Describe: _________________________________
_________________________________________
_________________________________________
Re: SWDM Adjustment No. ________________
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan: ____________________________________________________________________
Special District Overlays: ______________________________________________________________
Drainage Basin: _____________________________________________________________________
Stormwater Requirements: _____________________________________________________________
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
River/Stream ________________________
Lake ______________________________
Wetlands ____________________________
Closed Depression ____________________
Floodplain ___________________________
Other _______________________________
_______________________________
Steep Slope __________________________
Erosion Hazard _______________________
Landslide Hazard ______________________
Coal Mine Hazard ______________________
Seismic Hazard _______________________
Habitat Protection ______________________
_____________________________________
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3
Part 10 SOILS
Soil Type
______________________
______________________
______________________
______________________
Slopes
________________________
________________________
________________________
________________________
Erosion Potential
_________________________
_________________________
_________________________
_________________________
High Groundwater Table (within 5 feet)
Other ________________________________
Sole Source Aquifer
Seeps/Springs
Additional Sheets Attached
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE
Core 2 – Offsite Analysis_________________
Sensitive/Critical Areas__________________
SEPA________________________________
LID Infeasibility________________________
Other________________________________
_____________________________________
LIMITATION / SITE CONSTRAINT
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Threshold Discharge Area:
(name or description)
Core Requirements (all 8 apply):
Discharge at Natural Location Number of Natural Discharge Locations:
Offsite Analysis Level: 1 / 2 / 3 dated:__________________
Flow Control (include facility
summary sheet)
Standard: _______________________________
or Exemption Number: ____________
On-site BMPs: _______________________________
Conveyance System Spill containment located at: _____________________________
Erosion and Sediment Control /
Construction Stormwater Pollution
Prevention
CSWPP/CESCL/ESC Site Supervisor: _____________________
Contact Phone: _________________________
After Hours Phone: _________________________
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Maintenance and Operation Responsibility (circle one): Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and Liability Provided: Yes / No
Water Quality (include facility
summary sheet)
Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog
or Exemption No. _______________________
Special Requirements (as applicable):
Area Specific Drainage
Requirements
Type: SDO / MDP / BP / Shared Fac. / None
Name: ________________________
Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None
100-year Base Flood Elevation (or range): _______________
Datum:
Flood Protection Facilities Describe:
Source Control
(commercial / industrial land use)
Describe land use:
Describe any structural controls:
Oil Control High-Use Site: Yes / No
Treatment BMP: _________________________________
Maintenance Agreement: Yes / No
with whom? _____________________________________
Other Drainage Structures
Describe:
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
Clearing Limits
Cover Measures
Perimeter Protection
Traffic Area Stabilization
Sediment Retention
Surface Water Collection
Dewatering Control
Dust Control
Flow Control
Control Pollutants
Protect Existing and Proposed BMPs/Facilities
Maintain Protective BMPs / Manage Project
MINIMUM ESC REQUIREMENTS
AFTER CONSTRUCTION
Stabilize exposed surfaces
Remove and restore Temporary ESC Facilities
Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore
operation of BMPs/Facilities as necessary
Flag limits of sensitive areas and open space
preservation areas
Other _______________________
Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch)
Flow Control Type/Description Water Quality Type/Description
Detention
Infiltration
Regional Facility
Shared Facility
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
Vegetated Flowpath
Wetpool
Filtration
Oil Control
Spill Control
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
________________
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
Drainage Easement
Covenant
Native Growth Protection Covenant
Tract
Other ____________________________
Cast in Place Vault
Retaining Wall
Rockery > 4′ High
Structural on Steep Slope
Other _______________________________
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6
Part 17 SIGNATURE OF PROFESSIONAL ENGINEER
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
____________________________________________________________________________________ Signed/Date
January 8, 2020
Tab 2.0
20696.003-TIR
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
The project is subject to the Full Drainage Review since it results in greater than 2,000 square
feet of new plus replaced impervious surface and is therefore subject to all minimum
requirements. Below is an analysis of each core requirement:
2.1 Analysis of the Core Requirements
Core Requirement No. 1: Discharge at the Natural Location.
Response: The proposed redevelopment will continue to discharge at the natural and
existing location and thus not alter and/or adversely affect any downstream basins or
facilities.
Core Requirement No. 2: Off-Site Analysis.
Response: Per the City of Renton SWDM, the proposed project is exempt from Core
Requirement No. 2 as there will be no increase in discharge rate at the location of
discharge to and from the project site because the proposed condition will decrease the
existing impervious area by 2,000 square feet.
Core Requirement No. 3: Flow Control.
Response: The project site will replace less than 5,000 square feet of impervious surface
and less than three quarter acres of pervious surfaces will be added. This makes the
redevelopment exempt from providing flow control facilities.
Core Requirement No. 4: Conveyance System.
Response: The redevelopment has no change in flow characteristics and it will continue
to use the existing onsite conveyance system. Therefore, conveyance capacity analysis
is not needed.
Core Requirement No. 5: Erosion and Sediment Control
Response: To satisfy Core Requirement No. 5, a CSWPP along with a Stormwater
Pollution Prevention and Spill Plan (SWPPS) and Erosion Control Plan will be included
as part of this report within Section 8.
Core Requirement No. 6: Maintenance and Operations.
Response: The redevelopment includes regrading for the auto sentry station and trash
enclosure with a sewer connected catch basin, and the installation of an oil/water
separator. The catch basin maintenance and coalescing oil/water separator charts from
the City of Renton SWDM will be included in this report in Section 10.
Core Requirement No. 7: Financial Guarantees and Liability.
Response: All Financial Guarantees will be put in place as needed prior to permit
issuance.
20696.003-TIR
Core Requirement No. 8: Water Quality.
Response: The project meets the Surface Area Exemption to install water quality
facilities as stated in the City of Renton SWDM, as the proposed replaced pollution
generating impervious surfaces are less than 5,000 square feet and there will be less
than three quarter acres of pollution generating pervious surface added.
Core Requirement No. 9: On-site BMPs.
Response: The project will consider On-site BMPs for the target surfaces as feasible per
the Small Lot BMP Requirements detailed within the City of Renton SWDM. Further
discussion as to the feasibility of On-site BMPs can be found in Section 4.6.
2.2 Analysis of the Special Requirements
Special Requirement No. 1: Other Adopted Area-Specific Requirements.
Response: The project will meet all requirements as required based off project location
and area-specific requirements therein.
Special Requirement No. 2: Flood Hazard Area Delineation.
Response: As per the FEMA Flood Map Service Panel 53033C0977F, the area of the
project site is located in the 500-year floodplain, Zone X that largely includes areas of
minimal flooding. The project will adhere to any additional requirements as necessary.
Special Requirement No. 3: Flood Protection Facilities.
Response: The project site does not rely on an existing flood protection facility or modify
and construct a new flood protection facility as described in the City of Renton SWDM for
a redevelopment to comply Special Requirement No. 3. Thus, the implementation of
Flood Protection Facilities is not required.
Special Requirement No. 4: Source Control.
Response: The proposed project will implement source control measures as required
within the King County Stormwater Pollution Control Manual and Renton Municipal Code.
A roof will be required for the trash enclosure per CED Plan Review Decision dated
November 8, 2019. A catch basin with a vertical tee for oil control will be placed in the
trash enclosure to allow for self-containment.
Special Requirement No. 5: Oil Control.
Response: The redevelopment proposes more than $100,000 in improvements and is
classified as a high-use site. Special Requirement No. 5 will be implemented through the
installation of an oil/water separator to treat run-off. Please see Section 4.0 for further
information.
Special Requirement No. 6: Aquifer Protection Area.
Response: This redevelopment project is within the Wellhead Protection Zone No. 2;
however, the requirements specified for Zone No. 2 do not apply to this project because
20696.003-TIR
there are no flow control or water quality ponds, infiltration facilities, or open channels
proposed for this project.
Tab 3.0
20696.003-TIR.doc
3.0 OFF-SITE ANALYSIS
The proposed project does not intend to increase the discharge rate. It will maintain the same
location of discharge to and from the project site, and shall use the existing drainage network to
convey storm runoff to the public storm facilities. It is anticipated that the existing drainage and
conveyance system is adequate and has sufficient capacity to serve the site post-development
since there will be a significant net decrease in impervious area.
Tab 4.0
20696.003-TIR.doc
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
4.1 Existing Site Hydrology
The existing site hydrology sheet flows and collects into existing catch basins in
centralized locations within the site. The existing drainage network on-site consists of
three catch basins and pipes that convey stormwater runoff to a 12-inch pipe in the City
of Renton storm system.
4.2 Developed Site Hydrology
The redevelopment's drainage patterns will largely remain the same. Runoff from
impervious surfaces will be conveyed to the public storm network through existing and
proposed drainage and conveyance facilities, and a proposed oil water separator. The
redevelopment incorporates graded concrete and asphalt as a means to convey runoff to
the existing and proposed catch basins.
4.3 Performance Standards
The proposed redevelopment includes the replacement of hard surfaces and conversion
to pervious surfaces and is within the threshold for a Full Drainage Review as described
in the 2017 City of Renton Surface Water Design On-site BMPs per the Small Lot BMP
requirements. The feasibility of each On-site BMP is explained in Section 4.6.
Since the re-development is a high-use site, Special Requirement No. 5 - Oil control shall
be implemented on-site through the installation of an Oldcastle 660-SA Oil/Water
Separator, which will treat runoff to comply with the necessary oil control requirements.
This oil/water separator has been sized with the on-line water quality flow rate acquired
through WWHM. See Figure 9 and 10 for the Proposed Condition Map and Oil/Water
Separator Calculations.
4.4 Flow Control System
The project is required to consider Core Requirement No. 3; however, the City of Renton
SWDM presents a basic exemption, which includes the creation of less than 5,000
square feet of impervious surfaces and no addition of pervious surfaces. The
redevelopment falls under this criteria and will not propose any flow control facilities.
4.5 Water Quality System
Per the City of Renton SWDM, this project is exempt from the provision of water quality
facilities and is therefore, not included in the implementation of this Drainage Review.
4.6 On-site BMPs
As described in the City of Renton SWDM, Small Lot BMPs are required to be considered
for project sites under 22,000 square feet. The redevelopment, sized at 21,913 square
feet, triggers this requirement for target areas on-site where feasible. Discussion of the
required on-site BMPs are found below:
1. Full Dispersion
The required length of a vegetated flow path over a native vegetated surface required
per Appendix C of the Renton SWDM for full dispersion is not available for this
project site; thus, Full Dispersion in infeasible.
20696.003-TIR.doc
2. Full Infiltration of Roof Runoff
A site-specific Geologic Hazard Area Report, by ZipperGeo dated July 27, 2018,
determined the land on-site does not meet the criteria for a landslide hazard area;
however, the slope directly west of the site within the Hayes Place S.W. right-of-way
is a high Landslide Hazard Area. The 2017 City of Renton SWDM states in Section
C2.2.2.6 "Infiltration devices are not allowed within 50 feet of landslide hazard" areas.
When depicting this 50-foot setback on the west property line for infiltration devices.
Infiltration devices become infeasible for over half of the landscaped area. See the
Developed Conditions Map for a delineation of this setback. Additionally, the
geotechnical engineer found fill material onsite during subsurface explorations.
Appendix C of the Renton SWDM states the existing soils cannot be comprised of fill
materials where an infiltration device will be located. Since the site contains fill
material, infiltration is not feasible. See Section 6.1 for the Geotechnical Report.
3. Infiltration BMPs
a. Full Infiltration
The consideration above for full infiltration for roof downspouts applies to full
infiltration. The Renton SWDM states, in Appendix C, "Existing soils must be
coarse sands or cobbles or medium sands and cannot be comprised of fill
materials where the infiltration device will be located" (Renton SWDM 2017).
Since the site exhibits primarily fill soils, Full infiltration is not feasible.
b. Limited Infiltration
The site exhibits fill soils that consist of "silty sands with gravel to gravel with
variable silt sand" (ZipperGeo 2018). According to the minimum design
requirements for limited infiltration, "Silt and clay loams, cemented till
(hardpan) are not suitable for limited infiltration systems; therefore, limited
infiltration is not feasible" (Renton SWDM 2017).
c. Rain Gardens/Bioretention
Rain gardens and Bioretention BMPs are not feasible. Landscape areas with
adequate space are within 50 feet from a steep slope hazard and within 5
feet of a structure; therefore, due to insufficient "usable space for
Bioretention facilities" with this being a re-development site, Rain gardens
and Bioretention Facilities are infeasible (Renton SWDM 2017).
d. Permeable Pavement
The existing project site is classified as "high-use" due to the use and nature
of the existing business. This result to the infeasibility of using permeable
pavement in addition to the presence of fill material onsite.
4. Basic Dispersion
Adequate vegetated surfaces are not available, nor is there enough flow path length
as required within Appendix C of the 2017 Renton SWDM available, deeming Basic
Dispersion infeasible.
20696.003-TIR.doc
5. BMP Credits
a. Reduced Impervious Surface Credit
Due to the nature of the site being an existing commercial carwash, this BMP
Credit is not practical as the site is already fully developed and has no area
available to designate for reduction credits.
b. Native Growth Retention Credit
Due to the nature of the site being an existing commercial carwash, this BMP
Credit is not practical as the site is already fully developed, having no native
vegetation to retain.
c. Tree Retention Credit
The site proposes to retain the only existing tree surveyed on-site. This is
delineated to be retained in the TESC and Demolition Plan and Landscaping
Plan.
6. Soil Amendment BMP
The project proposes to convert existing impervious surface into pervious surface.
The pervious surface that is converted will be protected in accordance to the soil
amendment BMP found in the Manual Section C.2.13.
7. Perforated Pipe Roof Connections
The project does not propose any downspout pipe connections to the existing storm
conveyance system and fill material was reported onsite by the geotechnical
engineer; therefore, this Flow Control BMP is infeasible.
Based on the existing site characteristics and current use of the site, the
implementation of the above BMPs as discussed is infeasible.
Figure 8
Existing Conditions
Map
For:Title:206965BROWN BEARC2.0SCALE: 1"=30'
167
N
”
·
·
·
·
·
·
Figure 9
Proposed Conditions
Map
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
Dial 811
Callbefore you dig.
below.Know what's
RENTON BROWN BEAR AUTO SENTRY ADDITION
SCALE: 1"=20'
Figure 10
Oil/Water Separator
Calculations
OIL/WATER SEPARATOR SIZING CALCULATIONS
Project Name:Date:03/19/20
Site Location:Our Job No.:20626
Municipality:
Engineer:
Sizing per 2009 King County Surface Water Design Manual
Chapter 6 - Section 6.6.2.1 - Method for Coalescing Plate Separator (Page 6-149)
Specific Gravity of Water, Sw =1.0
Specific Gravity of Oil, So =0.85
Absolute Viscosity of Water, μ =0.015674
0.0763 CFS (per WWHM Calcs)
k = 2.74
12.54372
Required Effective Plate Area of Surface Media, Ah =339.94 SF
Brown Bear - Renton
77 Rainier Ave S
King County
Charm Salvino
Water Quality Design Flow Rate, Q =
Adjusted Water Quality Flow Rate( Q * k)
Use OldCastle Precast Oil Water Separator 660-CPS (Plate Area = 444 SF)
Page 1 of 1 20696 - Storm Oil-Water Separator Sizing Calcs.xlsx
Tab 5.0
20696.003-TIR.doc
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
The redevelopment does not propose to alter the existing conveyance system. The existing
conveyance system is expected to have sufficient capacity to convey the proposed conditions
since the site is significantly reducing the existing impervious area; thus, a Conveyance System
Analysis and Design is not included in this proposal.
Tab 6.0
20696.003-TIR.doc
6.0 SPECIAL REPORTS AND STUDIES
6.1 Geologic Hazard Report by ZipperGeo dated July 27, 2018
Tab 7.0
20696.003-TIR.doc
7.0 OTHER PERMITS
All other Permits in conjunction with a Full Drainage Review are listed below:
- Building Permit
Tab 8.0
20696.003-TIR.doc
8.0 STORMWATER POLLUTION PREVENTION PLAN (SWPP)
A Stormwater Pollution Prevention and Spill Plan and Erosion and Sediment Control Plan is
provided in this section on the following pages.
Stormwater Pollution Prevention Plan
(SWPPP)
Brown Bear Car Wash
Prepared for:
The Washington State Department of Ecology
Northwest Regional Office
3190 - 160th Avenue SE
Bellevue, WA 98008-5452
(425) 649-7000
Owner Developer Operator / Contractor
Car Wash Enterprises, Inc. TBD
Project Site Location
77 Rainier Avenue South
Renton, WA 98057
Certified Erosion and Sediment Control Lead (CESCL)
TBD
SWPPP Prepared By
Barghausen Consulting Engineers, Inc.
18215 - 72nd Avenue South
Kent, WA 98032
(425) 251-6222
Chris Jensen, Project Engineer
SWPPP Preparation Date
January 3, 2020
Project Construction Dates
TBD
1
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
2
List of Tables
Table 1 – pH-Modifying Sources ............................................................................................. 14
Table 2 – Management .............................................................................................................. 18
Table 3 – Team Information ..................................................................................................... 20
Table 4 – Turbidity Sampling Method ..................................................................................... 21
Table 5 – pH Sampling Method ................................................................................................ 23
List of Appendices
Appendix/Glossary
A. Site Map
B. BMP Detail
C. Site Inspection Form
3
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
4
1 Project Information
Project/Site Name: Brown Bear Car Wash
Street/Location: 77 Rainier Ave S
City: Renton State: WA Zip code: 98057
1.1 Existing Conditions
Total acreage (including support activities such as off-site equipment staging yards, material
storage areas, borrow areas).
Total acreage: 0.50
Disturbed acreage:
0.50
Existing structures:
Project site is currently developed with existing structures, asphalt paving,
storm, sewer, dry utilities and some landscaping.
Landscape topography:
The site is largely flat with slopes ranging from 1 to 5 percent on existing
paving.
Drainage patterns:
The existing drainage pattern sheet flows into centralized catch basins
and routes to public conveyance in Rainier Avenue South eastward of the
property.
Existing Vegetation:
The site has some existing landscaping and trees.
Critical Areas (wetlands, streams, high
erosion risk, steep or difficult to stabilize
slopes):
The project site located within a High
Erosion Hazard and high landslide hazard
zone. The Geologic Hazard report in the
Drainage report Section 6.1 discusses
these hazards.
1.2 Proposed Construction Activities
Description of site development (example: subdivision):
The proposed development includes the construction of an auto sentry station with a canopy, two
parking stalls with paint striping, a screened Covered trash enclosure, and landscaping.
Description of construction activities (example: site preparation, demolition, excavation):
Site preparation will include the demolition of existing structures and asphalt pavement.
Excavation of the existing USTs will take place under a separate permit. Site development will
commence once all of the existing structures and asphalt/concrete paving are disposed.
Construction activities will include regrading, construction of the auto sentry station and canopy,
installation of asphalt, concrete barrier curbs and landscaping. A catch basin with pipe connection
to the existing on site infrastructure will be included in the scope of work.
5
Description of site drainage including flow from and onto adjacent properties. Must be
consistent with Site Map in Appendix A:
The existing drainage pattern sheet flows into centralized catch basins and routes to public
conveyance in Rainier Avenue South eastward of the property.
Description of final stabilization (example: extent of revegetation, paving, landscaping):
Final stabilization of the site will generally include the installation of an auto sentry station, asphalt
pavement and landscaping.
6
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:
Adjacent properties to the construction site shall be protected and have minimal soil exposure by
properly marking the limits of construction around any land disturbing activities. A construction
fence will enclose all areas subject to construction, as well as delineate areas where no
construction is to take place. To protect soil and vegetation outside of the construction area, a silt
fence will be placed in areas as shown on the Demolition and TESC plan.
Refer to Appendix B: Construction BMPs for detailed drawings of the proposed BMPs. The
proposed BMPs relevant to clearing limits/vegetation preservation are:
• BMP C103 High Visibility Plastic or Metal Fence
• BMP C233 Silt 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: TBD
7
2.1.2 Element 2: Establish Construction Access
List and describe BMPs:
A construction entrance will not be required as the site will remain largely stabilized. Construction
vehicles are not expected to come into contact with exposed soils.
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
8
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: The developed site hydrology will remain relatively unchanged from
the existing site hydrology. There aren't any proposed stormwater systems proposed to alter flow
rates.
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
9
2.1.4 Element 4: Install Sediment Controls
List and describe BMPs:
Sediment control shall be implemented through the installation of a silt fence and inlet protections.
A silt fence will be placed in the necessary area where land disturbing will take place and may
contaminate with soils located in the adjacent property. Moreover, storm drain inlet protection
shall be installed to prevent sediment from entering drainage systems while construction is
ongoing.
See Appendix A: Location of silt fences on-site
See Appendix B: Detailed drawings of the proposed BMPs.
The proposed BMP that will be installed for sediment control is:
• BMP C233: Silt Fence
• BMP C220: Storm Drain Inlet Protection
Installation Schedules: Sediment Controls will be installed prior to any land disturbance activity.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
10
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. Depending on the time of year the
construction begins, additional BMP's for soil stabilization shall be required. Anticipated BMP's
such as straw, mulch, seeding along with the plastic covering are noted below.
See Appendix B: Detailed drawings of the BMPs used. The proposed BMPs specific to Soil
Stabilization are:
BMP C120 Temporary and Permanent Seeding
BMP C121 Mulching
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
11
2.1.6 Element 6: Protect Slopes
Will steep slopes be present at the site during construction?
Yes No
List and describe BMPs: Steep Slopes will not be present on this site for the duration of the
project. Therefore, there will be no proposed BMPs as they will not be needed.
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
12
2.1.7 Element 7: Protect Drain Inlets
List and describe BMPs:
Sediment shall be prevented from entering the drainage conveyance system through the
implementation of Storm Drain Inlet Protection. 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. Inlet protection devices shall be cleaned and replaced or removed
when sediment has filled 1/3 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 be maintained for the duration of the project.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
13
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: There will not be a significant amount of flows from this site and will
flow into catch basins within the Phase II site area. No BMPs will be required for channel
stabilization.
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
14
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
Table 1 – pH-Modifying Sources
None
15
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: ]
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
16
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 site has a high groundwater elevation. 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
17
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.
18
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 station(s) shall be 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 2 – 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)
19
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs
The project does not propose any Low Impact Development BMPs to be implemented as part of
this proposal. As such the project does not have a reason to implement BMPs to protect
proposed LID improvements.
20
3 Pollution Prevention Team
Table 3 – 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 Regional Office (425) 649-7000
21
4 Monitoring and Sampling Requirements
Monitoring includes visual inspection, sampling for water quality parameters of concern, and
documentation of the inspection and sampling findings in a site log book. A site log book will be
maintained for all on-site construction activities and will include:
A record of the implementation of the SWPPP and other permit requirements
Site inspections
Stormwater sampling data
The site log book must be maintained on-site within reasonable access to the site and be made
available upon request to Ecology or the local jurisdiction.
Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See
CSWGP Special Condition S8 and Section 5 of this template.
4.1 Site Inspection
Site inspections will be conducted at least once every calendar week and within 24 hours following
any discharge from the site. For sites that are temporarily stabilized and inactive, the required
frequency is reduced to once per calendar month.
The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with
the applicable requirements of the CSWGP.
4.2 Stormwater Quality Sampling
4.2.1 Turbidity Sampling
Requirements include calibrated turbidity meter or transparency tube to sample site discharges
for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once
per calendar week.
Method for sampling turbidity:
Table 4 – 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)
22
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.
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 to 10 percent over background turbidity, if background is 50 NTU or
greater
The discharge stops or is eliminated.
23
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:
Table 5 – pH Sampling Method
pH meter
pH test kit
Wide range pH indicator paper
24
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.
25
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 are 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.
26
27
Appendix/Glossary
A. Site Map
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
Dial 811
Callbefore you dig.
below.Know what's
BROWN BEAR CAR WASH
SCALE: 1"=20'
29
B. BMP Detail
BMP C103: High Visibility Plastic or Metal Fence
BMP C120 Temporary and Permanent Seeding
BMP C121 Mulching
BMP C123 Plastic Covering
BMP C140: Dust Control
BMP C150: Materials on Hand
BMP C151: Concrete Handling
BMP C152: Sawcutting and Surfacing Pollution Prevention
BMP C153: Material Delivery, Storage and Containment
BMP C154: Concrete Washout Area
BMP C160: Certified Erosion and Sediment Control Lead
BMP C162: Scheduling
BMP C220: Storm Drain Inlet Protection
BMP C233: Silt Fence
30
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.
31
BMP C120: Temporary and Permanent Seeding
Purpose
Seeding reduces erosion by stabilizing exposed soils. A well-established vegetative
cover is one of the most effective methods of reducing erosion.
Conditions of Use
Use seeding throughout the project on disturbed areas that have reached final grade or
that will remain unworked for more than 30 days.
The optimum seeding windows for western Washington are April 1 through June 30 and
September 1 through October 1.
Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is
established.
Between October 1 and March 30 seeding requires a cover of mulch with straw or an
erosion control blanket until 75 percent grass cover is established.
Review all disturbed areas in late August to early September and complete all seeding
by the end of September. Otherwise, vegetation will not establish itself enough to
provide more than average protection.
Mulch is required at all times for seeding because it protects seeds from heat,
moisture loss, and transport due to runoff. Mulch can be applied on top of the
seed or simultaneously by hydroseeding. See BMP C121: Mulching for
specifications.
Seed and mulch, all disturbed areas not otherwise vegetated at final site
stabilization. Final stabilization means the completion of all soil disturbing
activities at the site and the establishment of a permanent vegetative cover, or
equivalent permanent stabilization measures (such as pavement, riprap, gabions,
or geotextiles) which will prevent erosion.
Design and Installation Specifications
Seed retention/detention ponds as required.
32
Install channels intended for vegetation before starting major earthwork and hydroseed
with a Bonded Fiber Matrix. For vegetated channels that will have high flows, install
erosion control blankets over hydroseed. Before allowing water to flow in vegetated
channels, establish 75 percent vegetation cover. If vegetated channels cannot be
established by seed before water flow; install sod in the channel bottom—over
hydromulch and erosion control blankets.
Confirm the installation of all required surface water control measures to prevent
seed from washing away.
Hydroseed applications shall include a minimum of 1,500 pounds per acre of
mulch with 3 percent tackifier. See BMP C121: Mulching for specifications.
Areas that will have seeding only and not landscaping may need compost or
meal-based mulch included in the hydroseed in order to establish vegetation. Re-
install native topsoil on the disturbed soil surface before application.
When installing seed via hydroseeding operations, only about 1/3 of the seed
actually ends up in contact with the soil surface. This reduces the ability to
establish a good stand of grass quickly. To overcome this, consider increasing
seed quantities by up to 50 percent.
Enhance vegetation establishment by dividing the hydromulch operation into two
phases:
1. Phase 1- Install all seed and fertilizer with 25-30 percent mulch and tackifier
onto soil in the first lift.
2. Phase 2- Install the rest of the mulch and tackifier over the first lift.
Or, enhance vegetation by:
1. Installing the mulch, seed, fertilizer, and tackifier in one lift.
2. Spread or blow straw over the top of the hydromulch at a rate of 800-1000
pounds per acre.
3. Hold straw in place with a standard tackifier.
33
Both of these approaches will increase cost moderately but will greatly improve
and enhance vegetative establishment. The increased cost may be offset by the
reduced need for:
o Irrigation.
o Reapplication of mulch.
o Repair of failed slope surfaces.
This technique works with standard hydromulch (1,500 pounds per acre
minimum) and BFM/MBFMs (3,000 pounds per acre minimum).
Seed may be installed by hand if:
o Temporary and covered by straw, mulch, or topsoil.
o Permanent in small areas (usually less than 1 acre) and covered with
mulch, topsoil, or erosion blankets.
o The seed mixes listed in the tables below include recommended mixes for
both temporary and permanent seeding.
o Apply these mixes, with the exception of the wetland mix, at a rate of 120
pounds per acre. This rate can be reduced if soil amendments or slow-
release fertilizers are used.
o Consult the local suppliers or the local conservation district for their
recommendations because the appropriate mix depends on a variety of
factors, including location, exposure, soil type, slope, and expected foot
traffic. Alternative seed mixes approved by the local authority may be
used.
o Other mixes may be appropriate, depending on the soil type and
hydrology of the area.
Table II-4.1.2 Temporary Erosion Control Seed Mix lists the standard mix for
areas requiring a temporary vegetative cover.
34
Table II-4.1.2 Temporary Erosion Control Seed Mix
% Weight % Purity % Germination
Chewings or annual blue grass
Festuca rubra var. commutata or Poa anna
40 98 90
Perennial rye
Lolium perenne
50 98 90
Redtop or colonial bentgrass
Agrostis alba or Agrostis tenuis
5 92 85
White dutch clover
Trifolium repens
5 98 90
Table II-4.1.3 Landscaping Seed Mix lists a recommended mix for landscaping
seed.
Table II-4.1.3 Landscaping Seed Mix
% Weight % Purity % Germination
Perennial rye blend
Lolium perenne
70 98 90
Chewings and red fescue blend
Festuca rubra var. commutata or Festuca rubra
30 98 90
Table II-4.1.4 Low-Growing Turf Seed Mix lists a turf seed mix for dry situations
where there is no need for watering. This mix requires very little maintenance.
35
Table II-4.1.4 Low-Growing Turf Seed Mix
% Weight % Purity % Germination
Dwarf tall fescue (several varieties)
Festuca arundinacea var.
45 98 90
Dwarf perennial rye (Barclay)
Lolium perenne var. barclay
30 98 90
Red fescue
Festuca rubra
20 98 90
Colonial bentgrass
Agrostis tenuis
5 98 90
Table II-4.1.5 Bioswale Seed Mix* lists a mix for bioswales and other
intermittently wet areas.
Table II-4.1.5 Bioswale Seed Mix*
% Weight % Purity % Germination
Tall or meadow fescue
Festuca arundinacea or Festuca elatior
75-80 98 90
Seaside/Creeping bentgrass
Agrostis palustris
10-15 92 85
Redtop bentgrass
Agrostis alba or Agrostis gigantea
5-10 90 80
36
Table II-4.1.5 Bioswale Seed Mix*
% Weight % Purity % Germination
* Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix
Table II-4.1.6 Wet Area Seed Mix* lists a low-growing, relatively non-invasive
seed mix appropriate for very wet areas that are not regulated wetlands. Apply
this mixture at a rate of 60 pounds per acre. Consult Hydraulic Permit Authority
(HPA) for seed mixes if applicable.
Table II-4.1.6 Wet Area Seed Mix*
% Weight % Purity % Germination
Tall or meadow fescue
Festuca arundinacea or Festuca elatior
60-70 98 90
Seaside/Creeping bentgrass
Agrostis palustris
10-15 98 85
Meadow foxtail
Alepocurus pratensis
10-15 90 80
Alsike clover
Trifolium hybridum
1-6 98 90
Redtop bentgrass
Agrostis alba
1-6 92 85
* Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix
37
Table II-4.1.7 Meadow Seed Mix lists a recommended meadow seed mix for
infrequently maintained areas or non-maintained areas where colonization by
native plants is desirable. Likely applications include rural road and utility right-of-
way. Seeding should take place in September or very early October in order to
obtain adequate establishment prior to the winter months. Consider the
appropriateness of clover, a fairly invasive species, in the mix. Amending the soil
can reduce the need for clover.
Table II-4.1.7 Meadow Seed Mix
% Weight % Purity % Germination
Redtop or Oregon bentgrass
Agrostis alba or Agrostis oregonensis
20 92 85
Red fescue
Festuca rubra
70 98 90
White dutch clover
Trifolium repens
10 98 90
Roughening and Rototilling:
o The seedbed should be firm and rough. Roughen all soil no matter what
the slope. Track walk slopes before seeding if engineering purposes
require compaction. Backblading or smoothing of slopes greater than
4H:1V is not allowed if they are to be seeded.
o Restoration-based landscape practices require deeper incorporation than
that provided by a simple single-pass rototilling treatment. Wherever
practical, initially rip the subgrade to improve long-term permeability,
infiltration, and water inflow qualities. At a minimum, permanent areas
shall use soil amendments to achieve organic matter and permeability
performance defined in engineered soil/landscape systems. For systems
38
that are deeper than 8 inches complete the rototilling process in multiple
lifts, or prepare the engineered soil system per specifications and place to
achieve the specified depth.
Fertilizers:
o Conducting soil tests to determine the exact type and quantity of fertilizer
is recommended. This will prevent the over-application of fertilizer.
o Organic matter is the most appropriate form of fertilizer because it
provides nutrients (including nitrogen, phosphorus, and potassium) in the
least water-soluble form.
o In general, use 10-4-6 N-P-K (nitrogen-phosphorus-potassium) fertilizer at
a rate of 90 pounds per acre. Always use slow-release fertilizers because
they are more efficient and have fewer environmental impacts. Do not add
fertilizer to the hydromulch machine, or agitate, more than 20 minutes
before use. Too much agitation destroys the slow-release coating.
o There are numerous products available that take the place of chemical
fertilizers. These include several with seaweed extracts that are beneficial
to soil microbes and organisms. If 100 percent cottonseed meal is used as
the mulch in hydroseed, chemical fertilizer may not be necessary.
Cottonseed meal provides a good source of long-term, slow-release,
available nitrogen.
Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix:
o On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded
Fiber Matrix (MBFM) products. Apply BFM/MBFM products at a minimum
rate of 3,000 pounds per acre of mulch with approximately 10 percent
tackifier. Achieve a minimum of 95 percent soil coverage during
application. Numerous products are available commercially. Installed
products per manufacturer’s instructions. Most products require 24-36
hours to cure before rainfall and cannot be installed on wet or saturated
soils. Generally, products come in 40-50 pound bags and include all
necessary ingredients except for seed and fertilizer.
39
o BFMs and MBFMs provide good alternatives to blankets in most areas
requiring vegetation establishment. Advantages over blankets include:
BFM and MBFMs do not require surface preparation.
Helicopters can assist in installing BFM and MBFMs in remote
areas.
On slopes steeper than 2.5H:1V, blanket installers may require
ropes and harnesses for safety.
Installing BFM and MBFMs can save at least $1,000 per acre
compared to blankets.
Maintenance Standards
Reseed any seeded areas that fail to establish at least 80 percent cover (100 percent
cover for areas that receive sheet or concentrated flows). If reseeding is ineffective, use
an alternate method such as sodding, mulching, or nets/blankets. If winter weather
prevents adequate grass growth, this time limit may be relaxed at the discretion of the
local authority when sensitive areas would otherwise be protected.
Reseed and protect by mulch any areas that experience erosion after achieving
adequate cover. Reseed and protect by mulch any eroded area.
Supply seeded areas with adequate moisture, but do not water to the extent that it
causes runoff.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C120:
Temporary and Permanent Seeding. 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.
40
BMP C121: Mulching
Purpose
Mulching soils provides immediate temporary protection from erosion. Mulch also
enhances plant establishment by conserving moisture, holding fertilizer, seed, and
topsoil in place, and moderating soil temperatures. There is an enormous variety of
mulches that can be used. This section discusses only the most common types of
mulch.
Conditions of Use
As a temporary cover measure, mulch should be used:
For less than 30 days on disturbed areas that require cover.
At all times for seeded areas, especially during the wet season and during the
hot summer months.
During the wet season on slopes steeper than 3H:1V with more than 10 feet of
vertical relief.
Mulch may be applied at any time of the year and must be refreshed periodically.
For seeded areas mulch may be made up of 100 percent: cottonseed meal; fibers made
of wood, recycled cellulose, hemp, kenaf; compost; or blends of these. Tackifier shall be
plant-based, such as guar or alpha plantago, or chemical-based such as polyacrylamide
or polymers. Any mulch or tackifier product used shall be installed per manufacturer’s
instructions. Generally, mulches come in 40-50 pound bags. Seed and fertilizer are
added at time of application.
Design and Installation Specifications
For mulch materials, application rates, and specifications, see Table II-4.1.8 Mulch
Standards and Guidelines. Always use a 2-inch minimum mulch thickness; increase the
41
thickness until the ground is 95% covered (i.e. not visible under the mulch layer). Note:
Thickness may be increased for disturbed areas in or near sensitive areas or other
areas highly susceptible to erosion.
Where the option of “Compost” is selected, it should be a coarse compost that meets
the following size gradations when tested in accordance with the U.S. Composting
Council “Test Methods for the Examination of Compost and Composting” (TMECC) Test
Method 02.02-B.
Coarse Compost
Minimum Percent passing 3” sieve openings 100%
Minimum Percent passing 1” sieve openings 90%
Minimum Percent passing ¾” sieve openings 70%
Minimum Percent passing ¼” sieve openings 40%
Mulch used within the ordinary high-water mark of surface waters should be selected to
minimize potential flotation of organic matter. Composted organic materials have higher
specific gravities (densities) than straw, wood, or chipped material. Consult Hydraulic
Permit Authority (HPA) for mulch mixes if applicable.
Maintenance Standards
The thickness of the cover must be maintained.
Any areas that experience erosion shall be remulched and/or protected with a net
or blanket. If the erosion problem is drainage related, then the problem shall be
fixed and the eroded area remulched.
42
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
Straw
Air-dried; free from
undesirable seed and
coarse material.
2"-3" thick; 5
bales per 1,000
sf or 2-3 tons
per acre
Cost-effective protection when applied
with adequate thickness. Hand-
application generally requires greater
thickness than blown straw. The
thickness of straw may be reduced by half
when used in conjunction with seeding. In
windy areas straw must be held in place
by crimping, using a tackifier, or covering
with netting. Blown straw always has to
be held in place with a tackifier as even
light winds will blow it away. Straw,
however, has several deficiencies that
should be considered when selecting
mulch materials. It often introduces and/or
encourages the propagation of weed
species and it has no significant long-term
benefits It should also not be used within
the ordinary high-water elevation of
surface waters (due to flotation).
Hydromulch No growth inhibiting
factors.
Approx. 25-30
lbs per 1,000 sf
or 1,500 - 2,000
lbs per acre
Shall be applied with hydromulcher. Shall
not be used without seed and tackifier
unless the application rate is at least
doubled. Fibers longer than about 3/4 - 1
inch clog hydromulch equipment. Fibers
should be kept to less than 3/4 inch.
Compost
No visible water or
dust during handling.
Must be produced per
WAC 173-350, Solid
Waste Handling
Standards, but may
have up to 35%
biosolids.
2" thick min.;
approx. 100
tons per acre
(approx. 800 lbs
per yard)
More effective control can be obtained by
increasing thickness to 3". Excellent
mulch for protecting final grades until
landscaping because it can be directly
seeded or tilled into soil as an
amendment. Compost used for mulch has
a coarser size gradation than compost
used for BMP C125: Topsoiling /
Compostingor BMP T5.13: Post-
Construction Soil Quality and Depth. It is
more stable and practical to use in wet
areas and during rainy weather
43
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
conditions. Do not use near wetlands or
near phosphorous impaired water bodies.
Chipped Site
Vegetation
Average size shall be
several inches.
Gradations from fines
to 6 inches in length
for texture, variation,
and interlocking
properties.
2" thick min.;
This is a cost-effective way to dispose of
debris from clearing and grubbing, and it
eliminates the problems associated with
burning. Generally, it should not be used
on slopes above approx. 10% because of
its tendency to be transported by runoff. It
is not recommended within 200 feet of
surface waters. If seeding is expected
shortly after mulch, the decomposition of
the chipped vegetation may tie up
nutrients important to grass
establishment.
Wood-based
Mulch or
Wood Straw
No visible water or
dust during handling.
Must be purchased
from a supplier with a
Solid Waste Handling
Permit or one exempt
from solid waste
regulations.
2" thick min.;
approx. 100
tons per acre
(approx. 800
lbs. per cubic
yard)
This material is often called "hog or
hogged fuel".• The use of mulch
ultimately improves the organic matter in
the soil. Special caution is advised
regarding the source and composition of
wood-based mulches. Its preparation
typically does not provide any weed seed
control, so evidence of residual
vegetation in its composition or known
inclusion of weed plants or seeds should
be monitored and prevented (or
minimized).
Wood Strand
Mulch
A blend of loose,
long, thin wood
pieces derived from
native conifer or
deciduous trees with
high length-to-width
ratio.
2" thick min.
Cost-effective protection when applied
with adequate thickness. A minimum of
95-percent of the wood strand shall have
lengths between 2 and 10-inches, with a
width and thickness between 1/16 and
3/8-inches. The mulch shall not contain
resin, tannin, or other compounds in
quantities that would be detrimental to
plant life. Sawdust or wood shavings shall
44
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
not be used as mulch. (WSDOT
specification (9-14.4(4))
BMP C123: Plastic Covering
Purpose
Plastic covering provides immediate, short-term erosion protection to slopes and
disturbed areas.
Conditions of Use
Plastic covering may be used on disturbed areas that require cover measures for less
than 30 days, except as stated below.
Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note:
The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable
for long-term (greater than six months) applications.
Due to rapid runoff caused by plastic covering, do not use this method upslope of
areas that might be adversely impacted by concentrated runoff. Such areas
include steep and/or unstable slopes.
Plastic sheeting may result in increased runoff volumes and velocities, requiring
additional on-site measures to counteract the increases. Creating a trough with
wattles or other material can convey clean water away from these areas.
To prevent undercutting, trench and backfill rolled plastic covering products.
While plastic is inexpensive to purchase, the added cost of installation,
maintenance, removal, and disposal make this an expensive material, up to
$1.50-2.00 per square yard.
Whenever plastic is used to protect slopes install water collection measures at
the base of the slope. These measures include plastic-covered berms, channels,
and pipes used to covey clean rainwater away from bare soil and disturbed
areas. Do not mix clean runoff from a plastic covered slope with dirty runoff from
a project.
45
Other uses for plastic include:
o Temporary ditch liner.
o Pond liner in temporary sediment pond.
o Liner for bermed temporary fuel storage area if plastic is not reactive to
the type of fuel being stored.
o Emergency slope protection during heavy rains.
o Temporary drainpipe (“elephant trunk”) used to direct water.
Design and Installation Specifications
Plastic slope cover must be installed as follows:
1. Run plastic up and down slope, not across slope.
2. Plastic may be installed perpendicular to a slope if the slope length is less
than 10 feet.
3. Minimum of 8-inch overlap at seams.
4. On long or wide slopes, or slopes subject to wind, tape all seams.
5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top
of the slope and backfill with soil to keep water from flowing underneath.
6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and
tie them together with twine to hold them in place.
7. Inspect plastic for rips, tears, and open seams regularly and repair
immediately. This prevents high velocity runoff from contacting bare soil
which causes extreme erosion.
8. Sandbags may be lowered into place tied to ropes. However, all sandbags
must be staked in place.
Plastic sheeting shall have a minimum thickness of 0.06 millimeters.
If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable
protection shall be installed at the toe of the slope in order to reduce the velocity
of runoff.
Maintenance Standards
Torn sheets must be replaced and open seams repaired.
Completely remove and replace the plastic if it begins to deteriorate due to
ultraviolet radiation.
Completely remove plastic when no longer needed.
Dispose of old tires used to weight down plastic sheeting appropriately.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C123: Plastic
Covering. 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
46
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.
47
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.
48
BMP C150: Materials on Hand
Purpose
Keep quantities of erosion prevention and sediment control materials on the project site
at all times to be used for regular maintenance and emergency situations such as
unexpected heavy summer rains. Having these materials on-site reduces the time
needed to implement BMPs when inspections indicate that existing BMPs are not
meeting the Construction SWPPP requirements. In addition, contractors can save
money by buying some materials in bulk and storing them at their office or yard.
Conditions of Use
Construction projects of any size or type can benefit from having materials on
hand. A small commercial development project could have a roll of plastic and
some gravel available for immediate protection of bare soil and temporary berm
construction. A large earthwork project, such as highway construction, might
have several tons of straw, several rolls of plastic, flexible pipe, sandbags,
geotextile fabric and steel “T” posts.
Materials are stockpiled and readily available before any site clearing, grubbing,
or earthwork begins. A large contractor or developer could keep a stockpile of
materials that are available for use on several projects.
If storage space at the project site is at a premium, the contractor could maintain
the materials at their office or yard. The office or yard must be less than an hour
from the project site.
Design and Installation Specifications
Depending on project type, size, complexity, and length, materials and quantities will
vary. A good minimum list of items that will cover numerous situations includes:
Material
Clear Plastic, 6 mil
Drainpipe, 6 or 8 inch diameter
Sandbags, filled
Straw Bales for mulching,
Quarry Spalls
Washed Gravel
Geotextile Fabric
Catch Basin Inserts
Steel "T" Posts
Silt fence material
Straw Wattles
Maintenance Standards
All materials with the exception of the quarry spalls, steel “T” posts, and gravel
should be kept covered and out of both sun and rain.
Re-stock materials used as needed.
49
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:
50
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.
51
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.
52
BMP C153: Material Delivery, Storage and Containment
Purpose
Prevent, reduce, or eliminate the discharge of pollutants to the stormwater system or
watercourses from material delivery and storage. Minimize the storage of hazardous
materials on-site, store materials in a designated area, and install secondary
containment.
Conditions of Use
These procedures are suitable for use at all construction sites with delivery and
storage of the following materials:
Petroleum products such as fuel, oil and grease
Soil stabilizers and binders (e.g., Polyacrylamide)
Fertilizers, pesticides and herbicides
Detergents
Asphalt and concrete compounds
Hazardous chemicals such as acids, lime, adhesives, paints, solvents, and
curing compounds
Any other material that may be detrimental if released to the environment
Design and Installation Specifications
The following steps should be taken to minimize risk:
Temporary storage area should be located away from vehicular traffic, near the
construction entrance(s), and away from waterways or storm drains.
Material Safety Data Sheets (MSDS) should be supplied for all materials stored.
Chemicals should be kept in their original labeled containers.
Hazardous material storage on-site should be minimized.
Hazardous materials should be handled as infrequently as possible.
During the wet weather season (Oct 1 – April 30), consider storing materials in a
covered area.
Materials should be stored in secondary containments, such as earthen dike,
horse trough, or even a children’s wading pool for non-reactive materials such as
detergents, oil, grease, and paints. Small amounts of material may be
secondarily contained in “bus boy” trays or concrete mixing trays.
Do not store chemicals, drums, or bagged materials directly on the ground. Place
these items on a pallet and, when possible, and within secondary containment.
If drums must be kept uncovered, store them at a slight angle to reduce ponding
of rainwater on the lids to reduce corrosion. Domed plastic covers are
inexpensive and snap to the top of drums, preventing water from collecting.
Material Storage Areas and Secondary Containment Practices:
Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or
302 shall be stored in approved containers and drums and shall not be overfilled.
Containers and drums shall be stored in temporary secondary containment
facilities.
53
Temporary secondary containment facilities shall provide for a spill containment
volume able to contain 10% of the total enclosed container volume of all
containers, or 110% of the capacity of the largest container within its boundary,
whichever is greater.
Secondary containment facilities shall be impervious to the materials stored
therein for a minimum contact time of 72 hours.
Secondary containment facilities shall be maintained free of accumulated
rainwater and spills. In the event of spills or leaks, accumulated rainwater and
spills shall be collected and placed into drums. These liquids shall be handled as
hazardous waste unless testing determines them to be non-hazardous.
Sufficient separation should be provided between stored containers to allow for
spill cleanup and emergency response access.
During the wet weather season (Oct 1 – April 30), each secondary containment
facility shall be covered during non-working days, prior to and during rain events.
Keep material storage areas clean, organized and equipped with an ample
supply of appropriate spill clean-up material (spill kit).
The spill kit should include, at a minimum:
o 1-Water Resistant Nylon Bag
o 3-Oil Absorbent Socks 3”x 4’
o 2-Oil Absorbent Socks 3”x 10’
o 12-Oil Absorbent Pads 17”x19”
o 1-Pair Splash Resistant Goggles
o 3-Pair Nitrile Gloves
o 10-Disposable Bags with Ties
o Instructions
54
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
55
Discuss the concrete management techniques described in this BMP with the
ready-mix concrete supplier before any deliveries are made.
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.
56
Temporary Above-Grade Concrete Washout Facility
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 feet, 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.
57
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.
DEPAR TM E N T 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.
DEPAR TM E N T 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
61
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.
62
o Weather information; General conditions during inspection and
approximate amount of precipitation since the last inspection.
o 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.
63
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.
64
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 one to two feet 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).
65
Provide a height of 1 to 2 feet above inlet.
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.
DEPAR TM E N T OF
ECOLOGY
State of Washington
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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.
67
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.
68
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
DEPAR TM E N T 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
34 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
DEPAR TM E N T 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.
71
BMP C233: Silt Fence
Purpose
Use of a silt fence reduces the transport of coarse sediment from a construction site by
providing a temporary physical barrier to sediment and reducing the runoff velocities of
overland flow. See Figure II-4.2.12 Silt Fence (p.369) for details on silt fence
construction.
Conditions of Use
Silt fence may be used downslope of all disturbed areas.
Silt fence shall prevent soil carried by runoff water from going beneath, through,
or over the top of the silt fence, but shall allow the water to pass through the
fence.
Silt fence is not intended to treat concentrated flows, nor is it intended to treat
substantial amounts of overland flow. Convey any concentrated flows through the
drainage system to a sediment pond
Do not construct silt fences in streams or use in V-shaped ditches. Silt fences do
not provide an adequate method of silt control for anything deeper than sheet or
overland flow.
Design and Installation Specifications
Use in combination with sediment basins or other BMPs.
Maximum slope steepness (normal (perpendicular) to fence line) 1H:1V.
Maximum sheet or overland flow path length to the fence of 100 feet.
Do not allow flows greater than 0.5 cfs.
The geotextile used shall meet the following standards. All geotextile properties
listed below are minimum average roll values (i.e., the test result for any sampled
roll in a lot shall meet or exceed the values shown in Table II-4.2.3 Geotextile
Standards (p.370).
Support standard strength fabrics with wire mesh, chicken wire, 2-inch x 2-inch
wire, safety fence, or jute mesh to increase the strength of the fabric. Silt fence
materials are available that have synthetic mesh backing attached.
Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to
provide a minimum of six months of expected usable construction life at a
temperature range of 0°F. to 120°F.
One-hundred percent biodegradable silt fence is available that is strong, long
lasting, and can be left in place after the project is completed, if permitted by
local regulations.
Refer to Figure II-4.2.12 Silt Fence (p.369) for standard silt fence details. Include
the following standard Notes for silt fence on construction plans and
specifications:
1. The contractor shall install and maintain temporary silt fences at the locations
shown in the Plans.
2. Construct silt fences in areas of clearing, grading, or drainage prior to starting
those activities.
72
3. The silt fence shall have a 2-feet min. and a 2½-feet max. height above the
original ground surface.
4. The filter fabric shall be sewn together at the point of manufacture to form
filter fabric lengths as required. Locate all sewn seams at support posts.
Alternatively, two sections of silt fence can be overlapped, provided the
Contractor can demonstrate, to the satisfaction of the Engineer, that the
overlap is long enough and that the adjacent fence sections are close enough
together to prevent silt laden water from escaping through the fence at the
overlap.
5. Attach the filter fabric on the up-slope side of the posts and secure with
staples, wire, or in accordance with the manufacturer's recommendations.
Attach the filter fabric to the posts in a manner that reduces the potential for
tearing
6. 6. Support the filter fabric with wire or plastic mesh, dependent on the
properties of the geotextile selected for use. If wire or plastic mesh is used,
fasten the mesh securely to the up-slope side of the posts with the filter fabric
up-slope of the mesh.
7. Mesh support, if used, shall consist of steel wire with a maximum mesh
spacing of 2-inches, or a prefabricated polymeric mesh. The strength of the
wire or polymeric mesh shall be equivalent to or greater than 180 lbs. grab
tensile strength. The polymeric mesh must be as resistant to the same level
of ultraviolet radiation as the filter fabric it supports.
8. Bury the bottom of the filter fabric 4-inches min. below the ground surface.
Backfill and tamp soil in place over the buried portion of the filter fabric, so
that no flow can pass beneath the fence and scouring cannot occur. When
wire or polymeric back-up support mesh is used, the wire or polymeric mesh
shall extend into the ground 3-inches min.
9. Drive or place the fence posts into the ground 18-inches min. A 12–inch min.
depth is allowed if topsoil or other soft subgrade soil is not present and 18-
inches cannot be reached. Increase fence post min. depths by 6 inches if the
fence is located on slopes of 3H:1V or steeper and the slope is perpendicular
to the fence. If required post depths cannot be obtained, the posts shall be
adequately secured by bracing or guying to prevent overturning of the fence
due to sediment loading.
10. Use wood, steel or equivalent posts. The spacing of the support posts shall
be a maximum of 6-feet. Posts shall consist of either:
a. Wood with dimensions of 2-inches by 2-inches wide min. and a
3-feet min. length. Wood posts shall be free of defects such as
knots, splits, or gouges.
b. No. 6 steel rebar or larger.
c. ASTM A 120 steel pipe with a minimum diameter of 1-inch.
d. U, T, L, or C shape steel posts with a minimum weight of 1.35
lbs./ft.
e. Other steel posts having equivalent strength and bending
resistance to the post sizes listed above.
73
11. Locate silt fences on contour as much as possible, except at the ends of the
fence, where the fence shall be turned uphill such that the silt fence captures
the runoff water and prevents water from flowing around the end of the fence.
12. If the fence must cross contours, with the exception of the ends of the fence,
place gravel check dams perpendicular to the back of the fence to minimize
concentrated flow and erosion. The slope of the fence line where contours
must be crossed shall not be steeper than 3H:1V.
a. Gravel check dams shall be approximately 1-foot deep at the back of the
fence. Gravel check dams shall be continued perpendicular to the fence at
the same elevation until the top of the check dam intercepts the ground
surface behind the fence.
b. Gravel check dams shall consist of crushed surfacing base course, gravel
backfill for walls, or shoulder ballast. Gravel check dams shall be located
every 10 feet along the fence where the fence must cross contours.
Refer to Figure II-4.2.13 Silt Fence Installation by Slicing Method (p.374) for
slicing method details. Silt fence installation using the slicing method
specifications:
o The base of both end posts must be at least 2- to 4-inches above the top
of the filter fabric on the middle posts for ditch checks to drain properly.
Use a hand level or string level, if necessary, to mark base points before
installation.
o Install posts 3- to 4-feet apart in critical retention areas and 6- to 7-feet
apart in standard applications.
o Install posts 24-inches deep on the downstream side of the silt fence, and
as close as possible to the filter fabric, enabling posts to support the filter
fabric from upstream water pressure.
o Install posts with the nipples facing away from the filter fabric.
o Attach the filter fabric to each post with three ties, all spaced within the top
8-inches of the filter fabric. Attach each tie diagonally 45 degrees through
the filter fabric, with each puncture at least 1-inch vertically apart. Each tie
should be positioned to hang on a post nipple when tightening to prevent
sagging.
o Wrap approximately 6-inches of fabric around the end posts and secure
with 3 ties.
o No more than 24-inches of a 36-inch filter fabric is allowed above ground
level.
o Compact the soil immediately next to the filter fabric with the front wheel of
the tractor, skid steer, or roller exerting at least 60 pounds per square
inch.
o Compact the upstream side first and then each side twice for a total of four
trips. Check and correct the silt fence installation for any deviation before
compaction. Use a flat-bladed shovel to tuck fabric deeper into the ground
if necessary.
DEPAR TM E N T 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-4.2.12
Silt Fence
Revised October 2014
NOT TO SCALE
Joints in filter fabric shall be spliced
at posts. Use staples, wire rings or
equivalent to attach fabric to posts
6' max
Post spacing may be increased
to 8' if wire backing is used
2"x2" by 14 Ga. wire or equivalent,
if standard strength fabric used
Minimum
4"x4" trench
2"x2" wood posts, steel
fence posts, or equivalent
12" min
2' min
2"x2" by 14 Ga. wire or equivalent,
if standard strength fabric used
Filter fabric
Minimum
4"x4" trench
2"x2" wood posts, steel
fence posts, or equivalent
Backfill trench with
native soil or 34" -
1.5" washed gravel
76
C. Site Inspection Form
The results of each inspection shall be summarized in an inspection report or checklist that is
entered into or attached to the site log book. It is suggested that the inspection report or
checklist be included in this appendix to keep monitoring and inspection information in one
document, but this is optional; however, it is mandatory that this SWPPP and the site inspection
forms be kept on site at all times during construction, and that inspections be performed and
documented as outlined below:
At a minimum, each inspection report or checklist shall include:
1. Inspection date/times
2. Weather information: general conditions during inspection, approximate amount of
precipitation since the last inspection, and approximate amount of precipitation within the last
24 hours.
3. A summary or list of all BMPs that have been implemented, including observations of all
erosion/sediment control structures or practices.
4. The following shall be noted:
a. locations of BMPs inspected,
b. locations of BMPs that need maintenance,
c. the reason maintenance is needed,
d. locations of BMPs that failed to operate as designed or intended, and
e. locations where additional or different BMPs are needed, and the reason(s) why
5. A description of stormwater discharged from the site. The presence of suspended sediment,
turbid water, discoloration, and/or oil sheen shall be noted, as applicable.
6. A description of any water quality monitoring performed during inspection, and the results of
that monitoring.
7. General comments and notes, including a brief description of any BMP repairs, maintenance,
or installations made as a result of the inspection.
8. A statement that, in the judgment of the person conducting the site inspection, the site is either
in compliance or out of compliance with the terms and conditions of the SWPPP. If the site
inspection indicates that the site is out of compliance, the inspection report shall include a
summary of the remedial actions required to bring the site back into compliance, as well as a
schedule of implementation.
9. Name, title, and signature of person conducting the site inspection; and the following
statement: "I certify under penalty of law that this report is true, accurate, and complete, to
the best of my knowledge and belief."
When the site inspection indicates that the site is not in compliance with any terms and
conditions of the Permit, the CESCL shall take immediate action(s) to: stop, contain, and clean
up the unauthorized discharges, or otherwise stop the noncompliance; correct the problem(s);
implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of
existing BMPs; and achieve compliance with all applicable standards and permit conditions. In
addition, if the noncompliance causes a threat to human health or the environment, the CESCL
shall comply with the Noncompliance Notification requirements per Clark County standards.
77
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
78
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
79
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?
80
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?
81
Were BMPs used to prevent
contamination of stormwater by a pH
modifying sources?
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.
82
E. Check all areas that have been inspected.
All in place
BMPs
All disturbed
soils
All concrete wash out
area
All material storage
areas
All discharge
locations
All equipment storage
areas
All construction
entrances/exits
F. Elements checked “Action Required” (section D) describe corrective action to be taken. List the
element number; be specific on location and work needed. Document, initial, and date when the
corrective action has been completed and inspected.
Element
#
Description and Location Action Required Completion
Date
Initials
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:
STORMWATER POLLUTION PREVENTION AND SPILL (SWPPS) PLAN
Brown Bear Car Wash
77 Rainier Avenue South
Renton, Washington
City of Renton File No. TBD
Prepared for:
Car Wash Enterprises, Inc.
3977 Leary Way N.W.
Seattle, WA
January 8, 2020
Our Job No. 20696
STORMWATER POLLUTION PREVENTION AND SPILL (SWPPS) PLAN Barghausen Consulting Engineers, Inc. Brown Bear Car Wash Renton, Washington Our Job No. 20696
20696.005-Spill Plan.doc
TABLE OF CONTENTS
1.0 PROJECT AND SITE INFORMATION
- RESPONSIBLE PERSONNEL
2.0 STORAGE AND HANDLING OF LIQUIDS
3.0 STORAGE AND STOCKPILING OF CONSTRUCTION MATERIALS AND WASTES
4.0 FUELING
5.0 MAINTENANCE, REPAIRS, AND STORAGE OF VEHICLES AND EQUIPMENT
6.0 CONCRETE SAWCUTTING, SLURRY, AND WASHWATER DISPOSAL
7.0 HANDLING OF PH ELEVATED WATER
8.0 APPLICATION OF CHEMICALS INCLUDING PESTICIDES AND FERTILIZERS
9.0 SPILL RESPONSE AND CLEANUP
APPENDICES
APPENDIX A – DEMOLITION AND TESC PLAN
APPENDIX B – MATERIAL SAFETY DATA SHEETS
APPENDIX C – SPILL REPORT FORMS
20696.005-Spill Plan.doc
1.0 PROJECT AND SITE INFORMATION
The proposed project site is located within a portion of Section 18, Township 23 North, Range 5
East of the Willamette Meridian. More specifically, the site is located at 77 Rainier Avenue South.
The site is made up of one (1) Tax Parcel No. 182305-9131. See Figure 1 for the Vicinity Map in
this section for the location of the proposed project site.
The existing 21,913 square-foot site consists of an existing 1,836 square-foot car wash structure,
an existing gas station with canopy, asphalt and concrete pavement, and landscaping. The
proposed improvements include the removal of the existing gas station and appurtenances and
the construction of a new auto sentry pay station, which includes a new canopy, new
landscaping, and relocation of the dumpster enclosure. The driveway will be modified to be a 30-
foot wide driveway. The total onsite and offsite replaced impervious surface will be 4,912 square
feet. The existing car wash building will not be disturbed.
The site is relatively level with a rockery wall ranging from about 1 and a half to 4 feet tall. It is
located along the western property line and is the toe of the off-site east-facing slope. The project
intends to be completed with minimal modifications to the existing drainage network on-site. The
developed condition will rely on existing storm and sewer conveyance systems.
The contractor and sub-contractors have not been selected for this project yet. Once this is
complete, the information below will be completed.
Responsible Personnel:
Implementing and Updating the SWPPS:
Name: ____________
Company: ___________
Contact Number: ______________
Onsite Spill Responder:
Name: ____________
Company: ___________
Contact Number: ______________
Spill Response Subcontractor:
Name: ____________
Company: ___________
Contact Number: ______________
20696.005-Spill Plan.doc
2.0 STORAGE AND HANDLING OF LIQUIDS
It is anticipated that diesel fuel and gasoline will be stored onsite during construction. We
anticipate that no more than 20 gallons of each will be onsite at any one time. These liquids will
be stored under a covered area within the staging area on spill containment pallets (or approved
equal).
Form oil and bond breaker will also be used for concrete forming. We anticipate that no more
than 10 gallons will be onsite at any one time. This will be stored in the same location as the
diesel fuel and gasoline.
20696.005-Spill Plan.doc
3.0 STORAGE AND STOCKPILING OF CONSTRUCTION MATERIALS AND WASTES
With this project, we do not anticipate any construction wastes to be generated. In the event
wastes are generated, the Demolition and TESC plan shown in Appendix A provides a staging
area for the storage and stockpiling of construction materials and wastes. A dumpster with a solid
lid will be provided to contain these materials and prevent them from being exposed to rainwater.
20696.005-Spill Plan.doc
4.0 FUELING
Fueling of construction equipment will be completed with truck mounted tanks or individual 5-
gallon cans. There will be no stationary fuel tanks used for this construction project. Fueling of
construction equipment shall only take place during daylight hours, so no lighting or signage is
required.
20696.005-Spill Plan.doc
5.0 MAINTENANCE, REPAIRS, AND STORAGE OF VEHICLES AND EQUIPMENT
The SWPPS provided in Appendix A provides a graphic depiction of the equipment
“Parking/maintenance and repair” area. This area is located in the staging area.
Maintenance or repairs are not anticipated to occur onsite. In the event that this occurs,
equipment maintenance and repair, a drip pan or plastic shall be placed under the vehicle to
collect all fluids. Any fluids stored on the site shall be in sealed containers and placed in the
covered area provided in the staging area on the Demolition and TESC plan. Disposal of fluids
shall be done in accordance with state and federal requirements.
Signs will also be provided in the maintenance area to state that “No Vehicle Washing” may occur
in this area.
20696.005-Spill Plan.doc
6.0 CONCRETE SAW CUTTING, SLURRY, AND WASHWATER DISPOSAL
A truck washout area will not be required as the construction vehicles are not anticipated to drive
on exposed soils. The Demolition and TESC plan located in Appendix A provides a location for
concrete washout area within the staging area to wash concrete equipment and concrete hand
tools and dispose excess concrete.
This site is within a Zone 2 Aquifer Protection Area, so the concrete washout area shall be lined
and waste shall be disposed offsite.
20696.005-Spill Plan.doc
7.0 HANDLING OF PH ELEVATED WATER
The construction of the proposed concrete pad may cause collected water to have an elevated
pH. If pH levels exceed allowable limits, a separate permit will be obtained allowing discharge of
pH elevated water into the existing sanitary sewer system on-site.
20696.005-Spill Plan.doc
8.0 APPLICATION OF CHEMICALS INCLUDING PESTICIDES AND FERTILIZERS
There are no pesticides or fertilizers proposed to be used as part of this projects construction.
20696.005-Spill Plan.doc
9.0 SPILL REPONSE AND CLEANUP
There will be an air horn onsite that will be used in the event of a spill to assemble the crew to
take care of the spill. The area around the spill will be secured and a waste removal contractor
will be contacted (if necessary) to remove any hazardous waste that cannot be addressed by the
contractor. Spill response materials will be located in the staging area shown on the Demolition
and TESC located in Appendix A. Any disposal of any contaminated water or soil will be done in
accordance with state and federal laws.
Reports shall be completed and submitted to King County for any spills. See appendix C for Spill
Report Form.
20696.005-Spill Plan.doc
APPENDIX A
DEMOLITION AND TESC PLAN
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
Dial 811
Callbefore you dig.
below.Know what's
BROWN BEAR CAR WASH
SCALE: 1"=20'
20696.005-Spill Plan.doc
APPENDIX B
MATERIAL SAFETY DATA SHEETS
20696.005-Spill Plan.doc
APPENDIX C
SPILL REPORT FORMS
Tab 9.0
20696.003-TIR.doc
9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
The project will provide all documents pertaining to the Bond Quantities, Facility Summaries, and
Declaration of Covenants as required upon final engineering.
Tab 10.0
20696.003-TIR.doc
10.0 OPERATIONS AND MAINTENANCE MANUAL
The following pages represent the recommended maintenance operations to be performed on the
existing stormwater infrastructure.
APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS
2017 City of Renton Surface Water Design Manual 12/12/2016 A-35
NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR
MAINTENANCE
COMPONENT DEFECT
CONDITION WHEN MAINTENANCE
IS NEEDED
RESULTS EXPECTED WHEN
MAINTENANCE IS PERFORMED
Site Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility.
Contaminants and pollution Floating oil in excess of 1 inch in first chamber, any oil in other chambers or
other contaminants of any type in any chamber.
No contaminants present other than a surface oil film.
Vault Treatment
Area
Sediment
accumulation in the forebay
Sediment accumulation of 6 inches or
greater in the forebay.
No sediment in the forebay.
Discharge water not clear Inspection of discharge water shows obvious signs of poor water quality – effluent discharge from vault shows thick visible sheen.
Repair function of plates so effluent is clear.
Trash or debris accumulation Trash and debris accumulation in vault (floatables and non-floatables). Trash and debris removed from vault.
Oil accumulation Oil accumulation that exceeds 1 inch at the water surface in the in the coalescing plate chamber.
No visible oil depth on water and coalescing plates clear of oil.
Coalescing Plates Damaged Plate media broken, deformed, cracked and/or showing signs of failure. Replace that portion of media pack or entire plate pack depending on severity of failure.
Sediment accumulation Any sediment accumulation which interferes with the operation of the coalescing plates.
No sediment accumulation interfering with the coalescing plates.
Vault Structure Damage to wall, frame, bottom, and/or top slab
Cracks wider than ½-inch and any evidence of soil particles entering the structure through the cracks, or maintenance inspection personnel determines that the vault is not structurally sound.
Vault replaced or repaired to design specifications.
Baffles damaged Baffles corroding, cracking, warping and/or showing signs of failure as determined by maintenance/inspection person.
Repair or replace baffles to specifications.
Ventilation Pipes Plugged ventilation pipes Any obstruction to the ventilation pipes. Ventilation pipes are clear.
Shutoff Valve Damaged or inoperable shutoff valve
Shutoff valve cannot be opened or closed. Shutoff valve operates normally.
Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment.
Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables).
No trash or debris in pipes.
Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes.
No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe.
Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance.
Manhole access covered.
Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work.
Mechanism opens with proper tools.
APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS
12/12/2016 2017 City of Renton Surface Water Design Manual A-36
NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR
MAINTENANCE
COMPONENT DEFECT
CONDITION WHEN MAINTENANCE
IS NEEDED
RESULTS EXPECTED WHEN
MAINTENANCE IS PERFORMED
Access Manhole (cont.) Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person.
Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access.
Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed.
Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and cover access opening completely.
Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate.