HomeMy WebLinkAboutRS_Technical_Information_Report_220215_v1
TECHNICAL INFORMATION REPORT
Chevron Fuel System Replacement
1419 North 30th Street
Renton, WA 98056
City of Renton File No. TBD
Prepared for:
Chevron Stations, Inc.
575 Market Street
San Francisco, CA 94105
February 9, 2021
Our Job No. 21453
ALEX D O N A LD B
E
L
L
PRO
F
ESSION A L E N G INEERR
EGIS T E R E DSTATE O F W A SHIN
GTON21036182
02/09/2022
TABLE OF CONTENTS
1.0 PROJECT OVERVIEW
Figure 1 – Technical Information Report (TIR) Worksheet
Figure 2 -- Flow Chart for Determining Type of Drainage Review
Figure 3 – Vicinity Map
Figure 4 – Assessor Map
Figure 5 – FEMA Map
Figure 6 – Soil Survey Map
Figure 7 – Sensitive Areas Map
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
Not Included/Not Required)
4.0 FLOW CONTROL, LID, AND WATER QUALITY FCILITY ANALYSIS AND DESIGN
Not Included/Not Required)
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Not Included/Not Required)
6.0 SPECIAL REPORTS AND STUDIES
7.0 OTHER PERMITS
Not Included/Not Required)
8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION (CSWPP) ANALYSIS AND
DESIGN
A. Erosion and Sediment Control (ESC) Plan Analysis and Design
B. Stormwater Pollution Prevention and Spill (SWPPS) Plan Design
C. Stormwater Pollution Prevention Plan (SWPPP)
7.0 BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION OF COVENANT
Not Included/Not Required)
7.0 OPERATIONS AND MAINTENANCE MANUAL
Not Included/Not Required)
21453.003-TIR.doc
Tab 1.0
PROJECT OVERVIEW
The proposed project site is located within a portion of Section 32, Township 24 North, Range 5 East of
the Willamette Meridian. More specifically, the site is located at 1419 N 30th Street. The site is made up
of one (1) Tax Parcel No. 3342103271. See Figure 3 for the Vicinity Map in this section for the location of
the proposed project site.
The existing 71,172 square-foot (1.72 acres) site consists of an existing 1,800 square-foot convenience
store, an existing gas station with canopy, asphalt and concrete pavement, and landscaping. The site is
relatively level with a rockery wall ranging from about 1 and a half to 4 feet tall along the eastern property
line. The project intends to be completed with no modifications to the existing drainage network on-site
and the developed condition will rely on existing storm and sewer conveyance. The proposed
improvements include the removal and replacement of the existing underground storage tanks and fuel
appurtenances. The total onsite disturbance is 2,727 square feet, which is broken down to two areas as
replaced impervious surface area (427 square feet) and area disturbed for utility/maintenance
improvements (2,300 square feet). The site is subject to the 2017 City of Renton Surface Water Design
Manual (SWDM).
The site improvements involve the replacement of the three existing underground storage tanks and fuel
dispensers, which categorizes 2,300 square feet of the area disturbed as a maintenance project. The
area described is not considered 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 o f 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)."
Part of the improvements is the removal of an existing storage tank that will not be replaced, and will
result in backfilling and pavement construction of the excavation. This area (427 square feet) is
considered replaced impervious surface and is under the 2,000 square-foot area threshold for triggering
drainage review.
Per Section 1.1.1, Drainage Review is not required for projects proposing maintenance and projects
adding less than 2,000 square feet of replaced impervious area, and therefore, deems this project exempt
from Drainage Review.
As part of this Stormwater Memorandum, we are providing a Stormwater Pollution Prevention Plan found
in the next page to supplement our proposal.
Figure 1
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
__________________
__________________
__________________
Chevron Stations, Inc.
253-797-6545
575 Market Street
San Francisco, CA 94105
Alex Bell, P.E.
Barghausen Consulting Engineers
425-251-6222
Chevron Tank Replacement
24N
5E
1419 N 30th Street
9
9 9
11/6/2020
2/9/2022
TBD
11/6/2020
2/9/2022
TBD
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 ______________________
_____________________________________
N/A
Kenneydale
Urban Design District D
East Lake Washington-Renton
Core Requirement #5 and Special Requirements #1, #2, #3, #4, and #6
9 Wetland Protection Area Zone 2
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: _________________________
Indianola loamy sand 5 to 15 percent slopes Low
9
9
Wellhead Protection Area Zone 2. Infiltration Limits
LIDs not required to be analyzed fro project scope
On Site
1
N/A
N/A
N/A
N/A
TBD
N/A
N/A
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:
N/A
N/A
N/A
N/A
Ex. Convenience store and fuel station
Hydraulically isolated fueling stations
N/A
N/A
Centralized catch basins
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 _______________________________
9
9 9
9
9
9
9
9 9
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
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
2/9/2022
Figure 2
Flow Chart for Determining
Type of Drainage Review
Figure 3
Vicinity Map
Horizontal:
Scale:
Vertical:
For:
Title:
V IC IN IT Y M A P
Job Number
N.T.S.N/A
21453
D AT E: 11/03/20
Chevron 9-3878
Renton, Washington
P:\21000s\21453\exhibit\graphics\21453 vmap.cdr
RE FER ENC E: MapQuest (2020)
SITE
Figure 4
Assessor Map
Horizontal:
Scale:
Vertical:
For:
Title:
A S S E S S O R M A P
Job Number
N.T.S.N/A
21453
D AT E: 11/03/20
Chevron 9-3878
Renton, Washington
P:\21000s\21453\exhibit\graphics\21453 amap.cdr
SITE
RE FER ENC E: King County Department of Assessments (Sept. 2020)
Figure 5
FEMA Map
Horizontal:
Scale:
Vertical:
For:
Title:
F E M A M A P
Job Number
N.T.S.N/A
21453
D AT E: 11/03/20
Chevron 9-3878
Renton, Washington
P:\21000s\21453\exhibit\graphics\21453 fema.cdr
REFER EN CE: Federal Emergency Management Agency (Portion of Map 53033C0664G, Aug. 2020)
Areas determined to be outside the 0.2%
annual chance floodplain.
ZONE X
OTHER AREAS
L E G E N D
SITE
Figure 6
Soil Survey Map
Horizontal:
Scale:
Vertical:
For:
Title:
S O IL S U RV E Y M A P
Job Number
N.T.S.N/A
21453
D AT E: 11/03/20
Chevron 9-3878
Renton, Washington
P:\21000s\21453\exhibit\graphics\21453 soil.cdr
HSG
A
RE FER ENCE: US DA, Natural Resources Conservation Service
LE GEN D:
InC = Indianola loamy sand, 5-15% slopes
SITE
Figure 7
Sensitive Areas
Map
Horizontal:
Scale:
Vertical:
For:
Title:
S E N S IT IV E A R E A S
M A P
Job Number
N.T.S.N/A
21453
D AT E: 11/03/20
Chevron 9-3878
Renton, Washington
P:\21000s\21453\exhibit\graphics\21453 sens.cdr
SITE
RE FER ENC E: City of Renton COR maps (2020)
Tab 2.0
21453.003-TIR.doc
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
The project is subject to the Category No. 1 Targeted Drainage Review per the SWDM Flow chart
Figure 2) and Section 1.1.2.2 since the site is withi n a Wellhead Protection Area Zone 2, but
involves no replaced impervious surface (by definition as stated in Section 1.0). Per Section
1.1.2.2, the scope requirements include Core Requirement No. 5, Special Requirement numbers
1 through 4 and Special Requirement number 6.
2.1 Analysis of the Core Requirements
Core Requirement No. 5: Erosion and Sediment Control.
Response: To satisfy Core Requirement No. 5, a CSWPP containing with a Stormwater
Pollution Prevention and Spill Plan (SWPPS) and Erosion Control Plan will be included
as part of this report within Section 8 for any site disturbance work.
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 53033C0664G, 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 does not proposed to add new or modify existing
source control measures. The project will maintain existing source control measures as
required within the King County Stormwater Pollution Control Manual and Renton
Municipal Code.
Special Requirement No. 6: Aquifer Protection.
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
there are no flow control or water quality ponds, infiltration facilities, or open channels
proposed for this project.
Tab 6.0
21453.003-TIR.doc
6.0 SPECIAL REPORTS AND STUDIES
The following special reports and studies are included:
6.1 NRCS Soil Survey as of November 5, 2020.
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
King County
Area,
Washington
Natural
Resources
Conservation
Service
November 4, 2020
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map..................................................................................................................8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................11
Map Unit Descriptions.........................................................................................11
King County Area, Washington.......................................................................13
InC—Indianola loamy sand, 5 to 15 percent slopes....................................13
References............................................................................................................15
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil-vegetation-landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
Custom Soil Resource Report
6
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
8
9
Custom Soil Resource Report
Soil Map
5262980526299052630005263010526302052630305263040526305052630605263070526308052630905262980526299052630005263010526302052630305263040526305052630605263070526308052630905263100560220 560230 560240 560250 560260 560270 560280 560290 560300 560310
560220 560230 560240 560250 560260 560270 560280 560290 560300 560310
47° 31' 6'' N 122° 12' 0'' W47°
31' 6'' N122° 11' 56'' W47° 31' 2''
N
122° 12' 0'' W47° 31' 2'' N 122° 11' 56'' WN Map projection:
Web Mercator Corner coordinates: WGS84
Edge
tics: UTM Zone 10N WGS84
0
30 60 120 180 Feet 0 5 10 20 30 Meters Map Scale: 1:
625 if printed on A portrait (8.5" x
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: King County Area, Washington
Survey Area Data: Version 16, Jun 4, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 25, 2020—Jul 27,
2020
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
10
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
InC Indianola loamy sand, 5 to 15
percent slopes
2.0 100.0%
Totals for Area of Interest 2.0 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
Custom Soil Resource Report
11
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
12
King County Area, Washington
InC—Indianola loamy sand, 5 to 15 percent slopes
Map Unit Setting
National map unit symbol: 2t635
Elevation: 0 to 980 feet
Mean annual precipitation: 30 to 81 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 170 to 210 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Indianola and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Indianola
Setting
Landform:Eskers, kames, terraces
Landform position (three-dimensional):Riser
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Sandy glacial outwash
Typical profile
Oi - 0 to 1 inches: slightly decomposed plant material
A - 1 to 6 inches: loamy sand
Bw1 - 6 to 17 inches: loamy sand
Bw2 - 17 to 27 inches: sand
BC - 27 to 37 inches: sand
C - 37 to 60 inches: sand
Properties and qualities
Slope:5 to 15 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat excessively drained
Capacity of the most limiting layer to transmit water (Ksat):High to very high (5.95
to 99.90 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Available water capacity:Low (about 3.9 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4s
Hydrologic Soil Group: A
Forage suitability group: Droughty Soils (G002XS401WA), Droughty Soils
G002XN402WA)
Other vegetative classification: Droughty Soils (G002XS401WA), Droughty Soils
G002XN402WA)
Hydric soil rating: No
Custom Soil Resource Report
13
Minor Components
Alderwood
Percent of map unit:8 percent
Landform:Ridges, hills
Landform position (two-dimensional):Shoulder
Landform position (three-dimensional):Nose slope, talf
Down-slope shape:Linear, convex
Across-slope shape:Convex
Hydric soil rating: No
Everett
Percent of map unit:5 percent
Landform:Kames, eskers, moraines
Landform position (two-dimensional):Shoulder, footslope
Landform position (three-dimensional):Crest, base slope
Down-slope shape:Convex
Across-slope shape:Convex
Hydric soil rating: No
Norma
Percent of map unit:2 percent
Landform:Depressions, drainageways
Landform position (three-dimensional):Dip
Down-slope shape:Concave, linear
Across-slope shape:Concave
Hydric soil rating: Yes
Custom Soil Resource Report
14
References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
15
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
16
Tab 8.0
21453.003-TIR.doc
8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (CSWPPS) ANALYSIS
AND DESIGN
A. Erosion and Sediment Control (ESC) Plan
The Erosion and Sediment Control Plan is provided in this section on the following pages.
B. Stormwater Pollution Prevention and Spill (SWPPS) Plan Design
A Stormwater Pollution Prevention and Spill Plan is provided in this section on the
following pages.
A. Erosion and Sediment
Control (ESC) Plan
Analysis and Design
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
Dial 811
Callbefore you dig.
below.Know what's
CHEVRON TANK REPLACEMENT
CHEVRON FUEL SYSTEM REPLACEMENTALEX D O N A LD B
E
L
L
PRO
F
ESSIONA L E N G INEERREGIST E R E DSTATE O F W ASHIN
GTON21036182
NE 30TH STREET
HIGHWAY 405ON RAMP
Stormwater Pollution
Prevention and Spill
SWPPS) Plan Design
STORMWATER POLLUTION PREVENTION AND
SPILL (SWPPS) PLAN
Chevron Fuel System Replacement
1419 North 30th Street
Renton, WA 98056
City of Renton File No. TBD
Prepared for:
Chevron Stations, Inc.
575 Market Street
San Francisco, CA 94105
November 6, 2020
Our Job No. 21453
21453.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
APPENDIX A – DEMOLITION AND TESC PLAN
APPENDIX B – SPILL REPORT FORMS
Tab 1.0
21453.doc
1.0 PROJECT AND SITE INFORMATION
The proposed project site is located within a portion of Section 32, Township 24 North, Range 5
East of the Willamette Meridian. More specifically, the site is located at 1419 N 30th Street. The
site is made up of one (1) Tax Parcel No. 3342103271. See Figure 3 for the Vicinity Map in this
section for the location of the proposed project site.
The existing 71,172 square-foot (1.72 acres) site consists of an existing 1,800 square-foot
convenience store, an existing gas station with canopy, asphalt and concrete pavement, and
landscaping. The proposed improvements include the removal and replacement of the existing
Underground storage and appurtenances. The total onsite disturbance is 2,300 square feet.
The site is relatively level with a rockery wall ranging from about 1 and a half to 4 feet tall along
the eastern property line. The project intends to be completed with no 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: ______________
Tab 2.0
21453.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.
Tab 3.0
21453.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 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.
Tab 4.0
21453.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.
21453.doc
5.0 MAINTENANCE, REPAIRS, AND STORAGE OF VEHICLES AND EQUIPMENT
The TESC Plan 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 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.
Tab 6.0
21453.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. TESC plan located in Appendix A provides a location for concrete washo ut
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 shall area shall be
lined and waste shall be disposed offsite.
Tab 7.0
21453.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.
Tab 8.0
21453.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 construc tion.
Tab 9.0
21453.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 c rew 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 TESC Plan
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 B for Spill
Report Form.
21453.doc
APPENDIX A
DEMOLITION AND TESC PLAN
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
Dial 811
Callbefore you dig.
below.Know what's
CHEVRON TANK REPLACEMENT
CHEVRON FUEL SYSTEM REPLACEMENTALEX D O N A LD B
E
L
L
PRO
F
ESSIONA L E N G INEERREGIST E R E DSTATE O F W ASHIN
GTON21036182
NE 30TH STREET
HIGHWAY 405ON RAMP
21453.doc
APPENDIX B
SPILL REPORT FORMS
Stormwater Pollution
Prevention Plan
SWPPP)
Stormwater Pollution Prevention Plan
(SWPPP)
Chevron Fuel System Replacement - Renton, WA
Prepared for:
The Washington State Department of Ecology
Northwest Regional Office
3190 - 160th Avenue S.E.
Bellevue, WA 98008-5452
(425) 649-7000
Owner Developer Operator / Contractor
Chevron Stations, Inc. TBD
Project Site Location
1419 North 30th Street
Renton, WA 98056
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
Alex Bell, Project Engineer
SWPPP Preparation Date
December 29, 2021
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: Chevron Fuel System Replacement
Street/Location: 1419 North 30th Street
City: Renton State: WA Zip code: 98056
1.1 Existing Conditions
Total acreage (including support activities such as off-site equipment staging yards, material
storage areas, borrow areas).
Total acreage: 0.21
Disturbed acreage:
0.06
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 North 30th Street westward of the
property.
Existing Vegetation:
The site has some existing landscaping and trees with a forested area on
the southern half of the property.
Critical Areas (wetlands, streams, high
erosion risk, steep or difficult to stabilize
slopes):
The project site is located within Wellhead
Protection Zone No. 2.
1.2 Proposed Construction Activities
Description of site development (example: subdivision):
The proposed project's sole purpose is replacing the existing underground storage tanks (USTs)
and associated utilities.
Description of construction activities (example: site preparation, demolition, excavation):
Site preparation will include removing any pavement within the new UST footprint and in the path
of the associated utilities. The excavation of the existing USTs will take place under a separate
permit. Replacing the pavement will commence once all of the existing structures and
asphalt/concrete paving are disposed and USTs with associated utilities are installed.
Construction activities will installation of asphalt, concrete pavement, and concrete barrier curbs.
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 North 30th Street westward of the property.
Description of final stabilization (example: extent of revegetation, paving, landscaping):
Final stabilization of the site will generally include the installation asphalt and concrete pavement.
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. 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 Saw cutting 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 Alex Bell, 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.
27
Appendix/Glossary
A. Site Map
IN COMPLIANCE WITH CITY OF RENTON STANDARDS
Dial 811
Callbefore you dig.
below.Know what's
CHEVRON TANK REPLACEMENT
CHEVRON FUEL SYSTEM REPLACEMENTALEX D O N A LD B
E
L
L
PRO
FESSIONA L E N G INEERREGIST E R E DSTATE O F W ASHIN
GTON21036182
NE 30TH STREET
HIGHWAY 405ON RAMP
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 cov er, 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 m eets
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 / Composting or BMP T5.13:
Post-Construction Soil Quality and
Depth. It is more stable and practical to
43
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
use in wet areas and during rainy
weather 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
44
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
detrimental to plant life. Sawdust or
wood shavings shall 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 meth od 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
45
areas. Do not mix clean runoff from a plastic covered slope with dirty runoff from
a project.
• 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 lo cal
use. The products are available for review on Ecology’s website at
http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html
46
47
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.
48
• 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.
49
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.
50
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:
51
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.
52
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 const ructed 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.
53
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.
54
• 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
55
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
56
• 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.
57
• 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 tha t 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.
58
• 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 wea kening
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.
D E P A R T M E N T O F
E C O L O G Y
S t a t e o f W a s h i n g t o n
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.
D E P A R T M E N T O F
E C O L O G Y
S t a t e o f W a s h i n g t o n
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.
D EPARTMENT 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
62
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.
63
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.
64
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 lea ves 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.
65
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 pl ug 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).
66
• 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.
D E P A R T M E N T O F
E C O L O G Y
S t a t e o f W a s h i n g t o n
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.8
Block and Gravel Filter
Revised August 2015
NOT TO SCALE
Plan View
A
A
Section A-A
Drain grate
Concrete block
Gravel backfill
Less than5% slope
Gravel backfill
Concrete block
Water
Overflow
water
Drop inlet
Ponding height
Wire screen or
filter fabric
Notes:
1.Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less
than 5%)
2.Excavate a basin of sufficient size adjacent to the drop inlet.
3.The top of the structure (ponding height) must be well below the ground elevation
downslope to prevent runoff from bypassing the inlet. A temporary dike may be
necessary on the downslope side of the structure.
68
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.
Catch basin 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 catch basin filter with another type of inlet protection. This type
of inlet protection provides flow bypass without overflow and therefore may be a better
method for inlets located along active rights-of-way.
• 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 catch basin filter in the catch basin 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.
69
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
D E P A R T M E N T O F
E C O L O G Y
S t a t e o f W a s h i n g t o n
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.9
Block and Gravel Curb Inlet Protection
Revised August 2015
NOT TO SCALE
Plan View
A
A
Section A-A
Notes:
1.Use block and gravel type sediment barrier when curb inlet is located in gently sloping street
segment, where water can pond and allow sediment to separate from runoff.
2.Barrier shall allow for overflow from severe storm event.
3.Inspect barriers and remove sediment after each storm event. Sediment and gravel must be
removed from the traveled way immediately.
Back of sidewalk
Catch basin
Back of curb Curb inlet
Concrete block
2x4 Wood stud
Concrete block34 inch (20 mm)
Drain gravel
Wire screen or
filter fabric
3 4 inch (20 mm)
Drain gravel
Wire screen or
filter fabric
Ponding height
Overflow
2x4 Wood stud
(100x50 Timber stud)
Concrete block
Curb inlet
Catch basin
D E P A R T M E N T O F
E C O L O G Y
S t a t e o f W a s h i n g t o n
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.
72
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, though,
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.
73
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 pre sent 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.
74
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 perpend icular 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.
D E P A R T M E N T O F
E C O L O G Y
S t a t e o f W a s h i n g t o n
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 3 4" -
1.5" washed gravel
77
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.
78
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
79
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
80
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?
81
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?
82
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.
83
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: