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Home My WebLink AboutRS_Technical_Information_Report_201125_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 November 6, 2020 Our Job No. 21453 11/06/2020 Technical Information Report Barghausen Consulting Engineers, Inc. Chevron Fuel System Replacement Renton, Washington Our Job No. 21453 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 21453.003-TIR.doc 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 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 required to be designed per the 2017 City of Renton Surface Water Design Manual (SWDM). The site project solely involves the removal of the existing underground storage tanks, which 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 of Renton SWDM, "hard surfaces proposed for the sole purpose of installing utilities or p erforming maintenance on underground facilities, and hard surfaces that are proposed to be constructed without the removal of the base course or bare soil, are not considered as such (Replaced Impervious Surface)". The 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 to meet the Core and Special Requirements and satisfy the Category No. 1 Targeted Drainage Review as specified in the 2017 City of Renton Surface Design Manual and the City of Renton Municipal Code 4-6-030. Please See Figure 2 for the Flow Chart Determining the review type. The TIR worksheet is provided as Figure 1. 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 __________________ __________________ __________________ Anthony E. Merlino Barghausen Consulting Engineers, Inc. (425) 251-6222 Ext. 1065 REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2 Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: _______________________ Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: SWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: _____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ________________________  Lake ______________________________  Wetlands ____________________________  Closed Depression ____________________  Floodplain ___________________________  Other _______________________________ _______________________________  Steep Slope __________________________  Erosion Hazard _______________________  Landslide Hazard ______________________  Coal Mine Hazard ______________________  Seismic Hazard _______________________  Habitat Protection ______________________  _____________________________________ REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ On-site BMPs: _______________________________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4 Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. _______________________ Special Requirements (as applicable): Area Specific Drainage Requirements Type: SDO / MDP / BP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Describe: Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-Use Site: Yes / No Treatment BMP: _________________________________ Maintenance Agreement: Yes / No with whom? _____________________________________ Other Drainage Structures Describe: REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5 Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION  Clearing Limits  Cover Measures  Perimeter Protection  Traffic Area Stabilization  Sediment Retention  Surface Water Collection  Dewatering Control  Dust Control  Flow Control  Control Pollutants  Protect Existing and Proposed BMPs/Facilities  Maintain Protective BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION  Stabilize exposed surfaces  Remove and restore Temporary ESC Facilities  Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore operation of BMPs/Facilities as necessary  Flag limits of sensitive areas and open space preservation areas  Other _______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description  Detention  Infiltration  Regional Facility  Shared Facility  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________  Vegetated Flowpath  Wetpool  Filtration  Oil Control  Spill Control  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS  Drainage Easement  Covenant  Native Growth Protection Covenant  Tract  Other ____________________________  Cast in Place Vault  Retaining Wall  Rockery > 4′ High  Structural on Steep Slope  Other _______________________________ REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6 Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. ____________________________________________________________________________________ Signed/Date Chris Jensen, P.E. Principal/Vice President Figure 2 Flow Chart for Determining Type of Drainage Review Figure 3 Vicinity Map Horizontal: Scale: Vertical: For: Title: V I C I N I T 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 I L 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 I T I V 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 Ma nual 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 11") sheet. Soil Map may not be valid at this scale. 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 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 STORMWATER POLLUTION PREVENTION AND SPILL (SWPPS) PLAN Barghausen Consulting Engineers, Inc. Chevron Fuel System Replacement Renton, Washington 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, th e 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 21453.doc APPENDIX B SPILL REPORT FORMS Stormwater Pollution Prevention Plan (SWPPP) Stormwater Pollution Prevention Plan (SWPPP) Brown Bear Car Wash Prepared for: The Washington State Department of Ecology Northwest Regional Office 3190 - 160th Avenue SE Bellevue, WA 98008-5452 (425) 649-7000 Owner Developer Operator / Contractor 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 Chris Jensen, Project Engineer SWPPP Preparation Date November 6, 2020 Project Construction Dates TBD 1 Table of Contents 1 Project Information .............................................................................................................. 4 1.1 Existing Conditions ...................................................................................................... 4 1.2 Proposed Construction Activities .................................................................................. 4 2 Construction Stormwater Best Management Practices (BMPs) ........................................... 6 2.1 The 13 Elements .......................................................................................................... 6 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits ........................................ 6 2.1.2 Element 2: Establish Construction Access ............................................................ 7 2.1.3 Element 3: Control Flow Rates ............................................................................. 8 2.1.4 Element 4: Install Sediment Controls .................................................................... 9 2.1.5 Element 5: Stabilize Soils ....................................................................................10 2.1.6 Element 6: Protect Slopes....................................................................................11 2.1.7 Element 7: Protect Drain Inlets ............................................................................12 2.1.8 Element 8: Stabilize Channels and Outlets ..........................................................13 2.1.9 Element 9: Control Pollutants ...............................................................................14 2.1.10 Element 10: Control Dewatering ..........................................................................16 2.1.11 Element 11: Maintain BMPs .................................................................................17 2.1.12 Element 12: Manage the Project ..........................................................................18 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs .................................19 3 Pollution Prevention Team .................................................................................................20 4 Monitoring and Sampling Requirements ............................................................................21 4.1 Site Inspection ............................................................................................................21 4.2 Stormwater Quality Sampling ......................................................................................21 4.2.1 Turbidity Sampling ...............................................................................................21 4.2.2 pH Sampling ........................................................................................................23 5 Reporting and Record Keeping ..........................................................................................24 5.1 Record Keeping ..........................................................................................................24 5.1.1 Site Log Book ......................................................................................................24 5.1.2 Records Retention ...............................................................................................24 5.1.3 Updating the SWPPP ...........................................................................................24 5.2 Reporting ....................................................................................................................25 5.2.1 Discharge Monitoring Reports ..............................................................................25 5.2.2 Notification of Noncompliance ..............................................................................25 2 List of Tables Table 1 – pH-Modifying Sources ............................................................................................14 Table 2 – Management ............................................................................................................18 Table 3 – Team Information ....................................................................................................20 Table 4 – Turbidity Sampling Method ....................................................................................21 Table 5 – pH Sampling Method ..............................................................................................23 List of Appendices Appendix/Glossary A. Site Map B. BMP Detail C. Site Inspection Form 3 List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s) Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GULD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure Su Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model 4 1 Project Information Project/Site Name: 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: 0.05 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 N 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 installe. 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 N 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 Sawcutting and Surface Pollution Prevention • BMP C154 Concrete Washout Area Installation Schedules: BMPs shall be installed as necessary to control pollutants for the duration of construction. Inspection and Maintenance plan: TBD Responsible Staff: TBD Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site? Yes No Will wheel wash or tire bath system BMPs be used during construction? Yes No Will pH-modifying sources be present on-site? Yes No Table 1 – pH-Modifying Sources None 15 Bulk cement Cement kiln dust Fly ash Other cementitious materials New concrete washing or curing waters Waste streams generated from concrete grinding and sawing Exposed aggregate processes Dewatering concrete vaults Concrete pumping and mixer washout waters Recycled concrete Recycled concrete stockpiles Other (i.e., calcium lignosulfate) [please describe: ] Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on-site, except in designated concrete washout areas with appropriate BMPs installed. Will uncontaminated water from water-only based shaft drilling for construction of building, road, and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits discharge to surface waters? Yes No 16 2.1.10 Element 10: Control Dewatering  Discharge clean, non-turbid de-watering water, such as well-point groundwater, to systems tributary to, or directly into surface waters of the state, as specified in Element No. 8, provided the de-watering flow does not cause erosion or flooding of receiving waters or interfere with the operation of the system. Do not route clean dewatering water through stormwater sediment ponds. Note that "surface waters of the state" may exist on a construction site as well as off site; for example, a creek running through a site.  Highly turbid or contaminated dewatering water shall be handled separately from stormwater.  Clean, non-turbid dewatering water, such as well-point ground water, can be discharged to systems tributary to, or directly into surface waters of the state, provided the dewatering flow does not cause erosion or flooding of receiving waters. Clean dewatering water should not be routed through stormwater sediment ponds.  Other dewatering disposal options may include: o Transport off site in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state waters. o Infiltration. o Ecology-approved on-site chemical treatment or other suitable treatment technologies. o Sanitary sewer discharge with local sewer district approval, if there is no other option. o Use of a sedimentation bag with outfall to a ditch or swale for small volumes of localized dewatering. The project site has a high groundwater elevation. Dewatering activities may occur during the installation of on-site stormwater conveyance systems and/or excavation activities. Installation Schedules: Dewatering controls will be installed prior to any significant excavation activities. Inspection and Maintenance plan: TBD Responsible Staff: TBD 17 2.1.11 Element 11: Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. 18 2.1.12 Element 12: Manage the Project The project will be managed based on the following principles:  Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account.  Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling station(s) shall be located in accordance with applicable requirements of the CSWGP.  Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Table 2 – Management Design the project to fit the existing topography, soils, and drainage patterns Emphasize erosion control rather than sediment control Minimize the extent and duration of the area exposed Keep runoff velocities low Retain sediment on-site Thoroughly monitor site and maintain all ESC measures Schedule major earthwork during the dry season Other (please describe) 19 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs The project does not propose any Low Impact Development BMPs to be implemented as part of this proposal. As such the project does not have a reason to implement BMPs to protect proposed LID improvements. 20 3 Pollution Prevention Team Table 3 – Team Information Title Name(s) Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer Chris Jensen, P.E. (425) 251-6222 Emergency Ecology Contact Staff on Duty (425) 649-7130 Emergency Permittee/ Owner Contact TBD TBD Non-Emergency Owner Contact TBD TBD Monitoring Personnel TBD TBD Ecology Regional Office Northwest Regional Office (425) 649-7000 21 4 Monitoring and Sampling Requirements Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include:  A record of the implementation of the SWPPP and other permit requirements  Site inspections  Stormwater sampling data The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. 4.1 Site Inspection Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. 4.2 Stormwater Quality Sampling 4.2.1 Turbidity Sampling Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Table 4 – Turbidity Sampling Method Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) 22 The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Region’s Environmental Report Tracking System (ERTS) within 24 hours.  Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 or http://www.ecy.wa.gov/programs/spills/forms/nerts_online/NWRO_nerts_online.html 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true:  Turbidity is 25 NTU (or lower).  Transparency is 33 cm (or greater).  Compliance with the water quality limit for turbidity is achieved. o 1 - 5 NTU over background turbidity, if background is less than 50 NTU o 1 to 10 percent over background turbidity, if background is 50 NTU or greater  The discharge stops or is eliminated. 23 4.2.2 pH Sampling pH monitoring is required for “Significant concrete work” (i.e., greater than 1000 cubic yards poured concrete over the life of the project). The use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (CO2) sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: Table 5 – pH Sampling Method pH meter pH test kit Wide range pH indicator paper 24 5 Reporting and Record Keeping 5.1 Record Keeping 5.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include:  A record of the implementation of the SWPPP and other permit requirements  Site inspections  Sample logs 5.1.2 Records Retention Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.C of the CSWGP. Permit documentation to be retained on-site:  CSWGP  Permit Coverage Letter  SWPPP  Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. 5.1.3 Updating the SWPPP The SWPPP will be modified if:  Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site.  There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. 25 5.2 Reporting 5.2.1 Discharge Monitoring Reports Cumulative soil disturbance is less than one (1) acre; therefore, Discharge Monitoring Reports (DMRs) will not be submitted to Ecology because water quality sampling is not being conducted at the site. 5.2.2 Notification of Noncompliance If any of the terms and conditions of the permit are not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP.  Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. 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 29 B. BMP Detail  BMP C103: High Visibility Plastic or Metal Fence  BMP C120 Temporary and Permanent Seeding  BMP C121 Mulching  BMP C123 Plastic Covering  BMP C140: Dust Control  BMP C150: Materials on Hand  BMP C151: Concrete Handling  BMP C152: Sawcutting and Surfacing Pollution Prevention  BMP C153: Material Delivery, Storage and Containment  BMP C154: Concrete Washout Area  BMP C160: Certified Erosion and Sediment Control Lead  BMP C162: Scheduling  BMP C220: Storm Drain Inlet Protection  BMP C233: Silt Fence 30 BMP C103: High Visibility Fence Purpose Fencing is intended to: 1. Restrict clearing to approved limits. 2. Prevent disturbance of sensitive areas, their buffers, and other areas required to be left undisturbed. 3. Limit construction traffic to designated construction entrances, exits, or internal roads. 4. Protect areas where marking with survey tape may not provide adequate protection. Conditions of Use To establish clearing limits plastic, fabric, or metal fence may be used:  At the boundary of sensitive areas, their buffers, and other areas required to be left uncleared.  As necessary to control vehicle access to and on the site. Design and Installation Specifications High visibility plastic fence shall be composed of a high-density polyethylene material and shall be at least four feet in height. Posts for the fencing shall be steel or wood and placed every 6 feet on center (maximum) or as needed to ensure rigidity. The fencing shall be fastened to the post every six inches with a polyethylene tie. On long continuous lengths of fencing, a tension wire or rope shall be used as a top stringer to prevent sagging between posts. The fence color shall be high visibility orange. The fence tensile strength shall be 360 lbs./ft. using the ASTM D4595 testing method. If appropriate install fabric silt fence in accordance with BMP C233: Silt Fence (p.367) to act as high visibility fence. Silt fence shall be at least 3 feet high and must be highly visible to meet the requirements of this BMP. Metal fences shall be designed and installed according to the manufacturer's specifications. Metal fences shall be at least 3 feet high and must be highly visible. Fences shall not be wired or stapled to trees. Maintenance Standards If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. 31 BMP C120: Temporary and Permanent Seeding Purpose Seeding reduces erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use Use seeding throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. The optimum seeding windows for western Washington are April 1 through June 30 and September 1 through October 1. Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is established. Between October 1 and March 30 seeding requires a cover of mulch with straw or an erosion control blanket until 75 percent grass cover is established. Review all disturbed areas in late August to early September and complete all seeding by the end of September. Otherwise, vegetation will not establish itself enough to provide more than average protection.  Mulch is required at all times for seeding because it protects seeds from heat, moisture loss, and transport due to runoff. Mulch can be applied on top of the seed or simultaneously by hydroseeding. See BMP C121: Mulching for specifications.  Seed and mulch, all disturbed areas not otherwise vegetated at final site stabilization. Final stabilization means the completion of all soil disturbing activities at the site and the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as pavement, riprap, gabions, or geotextiles) which will prevent erosion. Design and Installation Specifications Seed retention/detention ponds as required. 32 Install channels intended for vegetation before starting major earthwork and hydroseed with a Bonded Fiber Matrix. For vegetated channels that will have high flows, install erosion control blankets over hydroseed. Before allowing water to flow in vegetated channels, establish 75 percent vegetation cover. If vegetated channels cannot be established by seed before water flow; install sod in the channel bottom—over hydromulch and erosion control blankets.  Confirm the installation of all required surface water control measures to prevent seed from washing away.  Hydroseed applications shall include a minimum of 1,500 pounds per acre of mulch with 3 percent tackifier. See BMP C121: Mulching for specifications.  Areas that will have seeding only and not landscaping may need compost or meal-based mulch included in the hydroseed in order to establish vegetation. Re- install native topsoil on the disturbed soil surface before application.  When installing seed via hydroseeding operations, only about 1/3 of the seed actually ends up in contact with the soil surface. This reduces the ability to establish a good stand of grass quickly. To overcome this, consider increasing seed quantities by up to 50 percent.  Enhance vegetation establishment by dividing the hydromulch operation into two phases: 1. Phase 1- Install all seed and fertilizer with 25-30 percent mulch and tackifier onto soil in the first lift. 2. Phase 2- Install the rest of the mulch and tackifier over the first lift. Or, enhance vegetation by: 1. Installing the mulch, seed, fertilizer, and tackifier in one lift. 2. Spread or blow straw over the top of the hydromulch at a rate of 800-1000 pounds per acre. 3. Hold straw in place with a standard tackifier. 33 Both of these approaches will increase cost moderately but will greatly improve and enhance vegetative establishment. The increased cost may be offset by the reduced need for: o Irrigation. o Reapplication of mulch. o Repair of failed slope surfaces. This technique works with standard hydromulch (1,500 pounds per acre minimum) and BFM/MBFMs (3,000 pounds per acre minimum).  Seed may be installed by hand if: o Temporary and covered by straw, mulch, or topsoil. o Permanent in small areas (usually less than 1 acre) and covered with mulch, topsoil, or erosion blankets. o The seed mixes listed in the tables below include recommended mixes for both temporary and permanent seeding. o Apply these mixes, with the exception of the wetland mix, at a rate of 120 pounds per acre. This rate can be reduced if soil amendments or slow- release fertilizers are used. o Consult the local suppliers or the local conservation district for their recommendations because the appropriate mix depends on a variety of factors, including location, exposure, soil type, slope, and e xpected foot traffic. Alternative seed mixes approved by the local authority may be used. o Other mixes may be appropriate, depending on the soil type and hydrology of the area.  Table II-4.1.2 Temporary Erosion Control Seed Mix lists the standard mix for areas requiring a temporary vegetative cover. 34 Table II-4.1.2 Temporary Erosion Control Seed Mix % Weight % Purity % Germination Chewings or annual blue grass Festuca rubra var. commutata or Poa anna 40 98 90 Perennial rye Lolium perenne 50 98 90 Redtop or colonial bentgrass Agrostis alba or Agrostis tenuis 5 92 85 White dutch clover Trifolium repens 5 98 90  Table II-4.1.3 Landscaping Seed Mix lists a recommended mix for landscaping seed. Table II-4.1.3 Landscaping Seed Mix % Weight % Purity % Germination Perennial rye blend Lolium perenne 70 98 90 Chewings and red fescue blend Festuca rubra var. commutata or Festuca rubra 30 98 90  Table II-4.1.4 Low-Growing Turf Seed Mix lists a turf seed mix for dry situations where there is no need for watering. This mix requires very little maintenance. 35 Table II-4.1.4 Low-Growing Turf Seed Mix % Weight % Purity % Germination Dwarf tall fescue (several varieties) Festuca arundinacea var. 45 98 90 Dwarf perennial rye (Barclay) Lolium perenne var. barclay 30 98 90 Red fescue Festuca rubra 20 98 90 Colonial bentgrass Agrostis tenuis 5 98 90  Table II-4.1.5 Bioswale Seed Mix* lists a mix for bioswales and other intermittently wet areas. Table II-4.1.5 Bioswale Seed Mix* % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca elatior 75-80 98 90 Seaside/Creeping bentgrass Agrostis palustris 10-15 92 85 Redtop bentgrass Agrostis alba or Agrostis gigantea 5-10 90 80 36 Table II-4.1.5 Bioswale Seed Mix* % Weight % Purity % Germination * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix  Table II-4.1.6 Wet Area Seed Mix* lists a low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wetlands. Apply this mixture at a rate of 60 pounds per acre. Consult Hydraulic Permit Authority (HPA) for seed mixes if applicable. Table II-4.1.6 Wet Area Seed Mix* % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca elatior 60-70 98 90 Seaside/Creeping bentgrass Agrostis palustris 10-15 98 85 Meadow foxtail Alepocurus pratensis 10-15 90 80 Alsike clover Trifolium hybridum 1-6 98 90 Redtop bentgrass Agrostis alba 1-6 92 85 * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix 37  Table II-4.1.7 Meadow Seed Mix lists a recommended meadow seed mix for infrequently maintained areas or non-maintained areas where colonization by native plants is desirable. Likely applications include rural road and utility right-of- way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. Consider the appropriateness of clover, a fairly invasive species, in the mix. Amending the soil can reduce the need for clover. Table II-4.1.7 Meadow Seed Mix % Weight % Purity % Germination Redtop or Oregon bentgrass Agrostis alba or Agrostis oregonensis 20 92 85 Red fescue Festuca rubra 70 98 90 White dutch clover Trifolium repens 10 98 90  Roughening and Rototilling: o The seedbed should be firm and rough. Roughen all soil no matter what the slope. Track walk slopes before seeding if engineering purposes require compaction. Backblading or smoothing of slopes greater than 4H:1V is not allowed if they are to be seeded. o Restoration-based landscape practices require deeper incorporation than that provided by a simple single-pass rototilling treatment. Wherever practical, initially rip the subgrade to improve long-term permeability, infiltration, and water inflow qualities. At a minimum, permanent areas shall use soil amendments to achieve organic matter and permeability performance defined in engineered soil/landscape systems. For systems 38 that are deeper than 8 inches complete the rototilling process in multiple lifts, or prepare the engineered soil system per specifications and place to achieve the specified depth.  Fertilizers: o Conducting soil tests to determine the exact type and quantity of fertilizer is recommended. This will prevent the over-application of fertilizer. o Organic matter is the most appropriate form of fertilizer because it provides nutrients (including nitrogen, phosphorus, and potassium) in the least water-soluble form. o In general, use 10-4-6 N-P-K (nitrogen-phosphorus-potassium) fertilizer at a rate of 90 pounds per acre. Always use slow-release fertilizers because they are more efficient and have fewer environmental impacts. Do not add fertilizer to the hydromulch machine, or agitate, more than 20 minutes before use. Too much agitation destroys the slow-release coating. o There are numerous products available that take the place of chemical fertilizers. These include several with seaweed extracts that are beneficial to soil microbes and organisms. If 100 percent cottonseed meal is used as the mulch in hydroseed, chemical fertilizer may not be necessary. Cottonseed meal provides a good source of long-term, slow-release, available nitrogen.  Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix: o On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix (MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre of mulch with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during application. Numerous products are available commercially. Installed products per manufacturer’s instructions. Most products require 24-36 hours to cure before rainfall and cannot be installed on wet or saturated soils. Generally, products come in 40-50 pound bags and include all necessary ingredients except for seed and fertilizer. 39 o BFMs and MBFMs provide good alternatives to blankets in most areas requiring vegetation establishment. Advantages over blankets include:  BFM and MBFMs do not require surface preparation.  Helicopters can assist in installing BFM and MBFMs in remote areas.  On slopes steeper than 2.5H:1V, blanket installers may require ropes and harnesses for safety.  Installing BFM and MBFMs can save at least $1,000 per acre compared to blankets. Maintenance Standards Reseed any seeded areas that fail to establish at least 80 percent cover (100 percent cover for areas that receive sheet or concentrated flows). If reseeding is ineffective, use an alternate method such as sodding, mulching, or nets/blankets. If winter weather prevents adequate grass growth, this time limit may be relaxed at the discretion of the local authority when sensitive areas would otherwise be protected.  Reseed and protect by mulch any areas that experience erosion after achieving adequate cover. Reseed and protect by mulch any eroded area.  Supply seeded areas with adequate moisture, but do not water to the extent that it causes runoff. Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C120: Temporary and Permanent Seeding. The products did not pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology’s website at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html . 40 BMP C121: Mulching Purpose Mulching soils provides immediate temporary protection from erosion. Mulch also enhances plant establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and moderating soil temperatures. There is an enormous variety of mulches that can be used. This section discusses only the most common types of mulch. Conditions of Use As a temporary cover measure, mulch should be used:  For less than 30 days on disturbed areas that require cover.  At all times for seeded areas, especially during the wet season and during the hot summer months.  During the wet season on slopes steeper than 3H:1V with more than 10 feet of vertical relief. Mulch may be applied at any time of the year and must be refreshed periodically.  For seeded areas mulch may be made up of 100 percent: cottonseed meal; fibers made of wood, recycled cellulose, hemp, kenaf; compost; or blends of these. Tackifier shall be plant-based, such as guar or alpha plantago, or chemical-based such as polyacrylamide or polymers. Any mulch or tackifier product used shall be installed per manufacturer’s instructions. Generally, mulches come in 40-50 pound bags. Seed and fertilizer are added at time of application. Design and Installation Specifications For mulch materials, application rates, and specifications, see Table II-4.1.8 Mulch Standards and Guidelines. Always use a 2-inch minimum mulch thickness; increase the 41 thickness until the ground is 95% covered (i.e. not visible under the mulch layer). Note: Thickness may be increased for disturbed areas in or near sensitive areas or other areas highly susceptible to erosion. Where the option of “Compost” is selected, it should be a coarse compost that meets the following size gradations when tested in accordance with the U.S. Composting Council “Test Methods for the Examination of Compost and Composting” (TMECC) Test Method 02.02-B. Coarse Compost Minimum Percent passing 3” sieve openings 100% Minimum Percent passing 1” sieve openings 90% Minimum Percent passing ¾” sieve openings 70% Minimum Percent passing ¼” sieve openings 40% Mulch used within the ordinary high-water mark of surface waters should be selected to minimize potential flotation of organic matter. Composted organic materials have higher specific gravities (densities) than straw, wood, or chipped material. Consult Hydraulic Permit Authority (HPA) for mulch mixes if applicable. Maintenance Standards  The thickness of the cover must be maintained.  Any areas that experience erosion shall be remulched and/or protected with a net or blanket. If the erosion problem is drainage related, then the problem shall be fixed and the eroded area remulched. 42 Table II-4.1.8 Mulch Standards and Guidelines Mulch Material Quality Standards Application Rates Remarks Straw Air-dried; free from undesirable seed and coarse material. 2"-3" thick; 5 bales per 1,000 sf or 2-3 tons per acre Cost-effective protection when applied with adequate thickness. Hand- application generally requires greater thickness than blown straw. The thickness of straw may be reduced by half when used in conjunction with seeding. In windy areas straw must be held in place by crimping, using a tackifier, or covering with netting. Blown straw always has to be held in place with a tackifier as even light winds will blow it away. Straw, however, has several deficiencies that should be considered when selecting mulch materials. It often introduces and/or encourages the propagation of weed species and it has no significant long- term benefits It should also not be used within the ordinary high-water elevation of surface waters (due to flotation). Hydromulch No growth inhibiting factors. Approx. 25-30 lbs per 1,000 sf or 1,500 - 2,000 lbs per acre Shall be applied with hydromulcher. Shall not be used without seed and tackifier unless the application rate is at least doubled. Fibers longer than about 3/4 - 1 inch clog hydromulch equipment. Fibers should be kept to less than 3/4 inch. Compost No visible water or dust during handling. Must be produced per WAC 173-350, Solid Waste Handling Standards, but may have up to 35% biosolids. 2" thick min.; approx. 100 tons per acre (approx. 800 lbs per yard) More effective control can be obtained by increasing thickness to 3". Excellent mulch for protecting final grades until landscaping because it can be directly seeded or tilled into soil as an amendment. Compost used for mulch has a coarser size gradation than compost used for BMP C125: Topsoiling / 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 method upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes.  Plastic sheeting may result in increased runoff volumes and velocities, requiring additional on-site measures to counteract the increases. Creating a trough with wattles or other material can convey clean water away from these areas.  To prevent undercutting, trench and backfill rolled plastic covering products.  While plastic is inexpensive to purchase, the added cost of installation, maintenance, removal, and disposal make this an expensive material, up to $1.50-2.00 per square yard.  Whenever plastic is used to protect slopes install water collection measures at the base of the slope. These measures include plastic-covered berms, channels, and pipes used to covey clean rainwater away from bare soil and disturbed 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 d irect water. Design and Installation Specifications  Plastic slope cover must be installed as follows: 1. Run plastic up and down slope, not across slope. 2. Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet. 3. Minimum of 8-inch overlap at seams. 4. On long or wide slopes, or slopes subject to wind, tape all seams. 5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top of the slope and backfill with soil to keep water from flowing underneath. 6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and tie them together with twine to hold them in place. 7. Inspect plastic for rips, tears, and open seams regularly and repair immediately. This prevents high velocity runoff from contacting bare soil which causes extreme erosion. 8. Sandbags may be lowered into place tied to ropes. However, all sandbags must be staked in place.  Plastic sheeting shall have a minimum thickness of 0.06 millimeters.  If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff. Maintenance Standards  Torn sheets must be replaced and open seams repaired.  Completely remove and replace the plastic if it begins to deteriorate due to ultraviolet radiation.  Completely remove plastic when no longer needed.  Dispose of old tires used to weight down plastic sheeting appropriately. Approved as Equivalent Ecology has approved products as able to meet the requirements of BMP C123: Plastic Covering. The products did not pass through the Technology Assessment Protocol Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology’s website at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html 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 constructed drainage conveyance including stormwater systems. This may require temporarily blocking catch basins.  Dispose of collected slurry and cuttings in a manner that does not violate ground water or surface water quality standards.  Do not allow process water generated during hydro-demolition, surface roughening or similar operations to drain to any natural or constructed drainage conveyance including stormwater systems. Dispose process water in a manner that does not violate ground water or surface water quality standards.  Handle and dispose cleaning waste material and demolition debris in a manner that does not cause contamination of water. Dispose of sweeping material from a pick-up sweeper at an appropriate disposal site. Maintenance Standards Continually monitor operations to determine whether slurry, cuttings, or proce ss 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 detrim ental 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 wa ter. 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 that compromise the impermeability of the material.  Temporary Below-Grade Concrete Washout Facility.  Temporary concrete washout facilities (type below grade) should be constructed as shown on the details below, with a recommended minimum length and minimum width of 10 ft. The quantity and volume should be sufficient to contain all liquid and concrete waste generated by washout operations.  Lath and flagging should be commercial type.  Plastic lining material shall be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the impermeability of the material.  Liner seams shall be installed in accordance with manufacturers’ recommendations.  Soil base shall be prepared free of rocks or other debris that may cause tears or holes in the plastic lining material.  Maintenance Standards Inspection and Maintenance  Inspect and verify that concrete washout BMPs are in place prior to the commencement of concrete work.  During periods of concrete work, inspect daily to verify continued performance. o Check overall condition and performance. o Check remaining capacity (% full). o If using self-installed washout facilities, verify plastic liners are intact and sidewalls are not damaged. o If using prefabricated containers, check for leaks.  Washout facilities shall be maintained to provide adequate holding capacity with a minimum freeboard of 12 inches.  Washout facilities must be cleaned, or new facilities must be constructed and ready for use once the washout is 75% full.  If the washout is nearing capacity, vacuum and dispose of the waste material in an approved manner.  Do not discharge liquid or slurry to waterways, storm drains or directly onto ground.  Do not use sanitary sewer without local approval.  Place a secure, non-collapsing, non-water collecting cover over the concrete washout facility prior to predicted wet weather to prevent accumulation and overflow of precipitation. 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 weakening or damage, and make any necessary repairs. Re-line the structure with new plastic after each cleaning. Removal of Temporary Concrete Washout Facilities  When temporary concrete washout facilities are no longer required for the work, the hardened concrete, slurries and liquids shall be removed and properly disposed of.  Materials used to construct temporary concrete washout facilities shall be removed from the site of the work and disposed of or recycled.  Holes, depressions or other ground disturbance caused by the removal of the temporary concrete washout facilities shall be backfilled, repaired, and stabilized to prevent erosion. 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 leaves a site vulnerable to accelerated erosion. Construction procedures that limit land clearing provide timely installation of erosion and sedimentation controls, and restore protective cover quickly can significantly reduce the erosion potential of a site. Design Considerations  Minimize construction during rainy periods.  Schedule projects to disturb only small portions of the site at any one time. Complete grading as soon as possible. Immediately stabilize the disturbed portion before grading the next portion. Practice staged seeding in order to revegetate cut and fill slopes as the work progresses. 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 plug and require a high frequency of maintenance. Limit drainage areas to one acre or less. Possibly provide emergency overflows with additional end-of-pipe treatment where stormwater ponding would cause a hazard. Design and Installation Specifications Excavated Drop Inlet Protection - An excavated impoundment around the storm drain. Sediment settles out of the stormwater prior to entering the storm drain.  Provide a depth of one to two feet as measured from the crest of the inlet structure.  Slope sides of excavation no steeper than 2H:1V.  Minimum volume of excavation 35 cubic yard.  Shape basin to fit site with longest dimension oriented toward the longest inflow area.  Install provisions for draining to prevent standing water problems.  Clear the area of all debris.  Grade the approach to the inlet uniformly.  Drill weep holes into the side of the inlet.  Protect weep holes with screen wire and washed aggregate.  Seal weep holes when removing structure and stabilizing area.  Build a temporary dike, if necessary, to the down slope side of the structure to prevent bypass flow. Block and Gravel Filter - A barrier formed around the storm drain inlet with standard concrete blocks and gravel. See Figure II-4.2.8 Block and Gravel Filter (p.360). 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 th is 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 present and 18- inches cannot be reached. Increase fence post min. depths by 6 inches if the fence is located on slopes of 3H:1V or steeper and the slope is perpendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent overturning of the fence due to sediment loading. 10. Use wood, steel or equivalent posts. The spacing of the support posts shall be a maximum of 6-feet. Posts shall consist of either: a. Wood with dimensions of 2-inches by 2-inches wide min. and a 3-feet min. length. Wood posts shall be free of defects such as knots, splits, or gouges. b. No. 6 steel rebar or larger. c. ASTM a 120 steel pipe with a minimum diameter of 1-inch. d. U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft. e. Other steel posts having equivalent strength and bending resistance to the post sizes listed above. 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 perpendicular to the fence at the same elevation until the top of the check dam intercepts the ground surface behind the fence. b. Gravel check dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. Gravel check dams shall be located every 10 feet along the fence where the fence must cross contours.  Refer to Figure II-4.2.13 Silt Fence Installation by Slicing Method (p.374) for slicing method details. Silt fence installation using the slicing method specifications: o The base of both end posts must be at least 2- to 4-inches above the top of the filter fabric on the middle posts for ditch checks to drain properly. Use a hand level or string level, if necessary, to mark base points before installation. o Install posts 3- to 4-feet apart in critical retention areas and 6- to 7-feet apart in standard applications. o Install posts 24-inches deep on the downstream side of the silt fence, and as close as possible to the filter fabric, enabling posts to support the filter fabric from upstream water pressure. o Install posts with the nipples facing away from the filter fabric. o Attach the filter fabric to each post with three ties, all spaced within the top 8-inches of the filter fabric. Attach each tie diagonally 45 degrees through the filter fabric, with each puncture at least 1-inch vertically apart. Each tie should be positioned to hang on a post nipple when tightening to prevent sagging. o Wrap approximately 6-inches of fabric around the end posts and secure with 3 ties. o No more than 24-inches of a 36-inch filter fabric is allowed above ground level. o Compact the soil immediately next to the filter fabric with the front wheel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. o Compact the upstream side first and then each side twice for a total of four trips. Check and correct the silt fence installation for any deviation before compaction. Use a flat-bladed shovel to tuck fabric deeper into the ground if necessary. 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: