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HomeMy WebLinkAboutRS_TIR_180830_v1 Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors Technical Information Report PREPARED FOR: Northwest Gourmet Food Products, Inc. 600 SW 7th Street Renton, WA 98057-2916 Contact: Mike Gilroy PROJECT: Northwest Gourmet Freezer Addition 600 SW 7th Street Renton, WA 98057-2916 AHBL No. 2160966.10 PREPARED BY: Tyler D. Watkins, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager J. Matthew Weber, PE Principal DATE: June 2018 Revised September 2018 RECEIVED 11/14/2018 jtaylor PLANNING DIVISION Technical Information Report PREPARED FOR: Northwest Gourmet Food Products, Inc. 600 SW 7th Street Renton, WA 98057-2916 Contact: Mike Gilroy PROJECT: Northwest Gourmet Freezer Addition 600 SW 7th Street Renton, WA 98057-2916 AHBL No. 2160966.10 PREPARED BY: Tyler D. Watkins, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager J. Matthew Weber, PE Principal DATE: June 2018 Revised September 2018 I hereby state that this Technical Information Report for the Northwest Gourmet Freezer Addition project has been prepared by me or under my supervision, and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that the City of Renton does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. Technical Information Report i Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Table of Contents 1.0 Project Overview ......................................................................................................................... 1-1 Purpose and Scope.......................................................................................................... 1-1 1.1 Existing Conditions........................................................................................................... 1-1 1.2 Post-Development Conditions ......................................................................................... 1-1 1.3 Section 1.0 Figures Figure 1-1 ......... TIR Worksheet Figure 1-2 ......... Vicinity Map Figure 1-3 ......... Permit Set Figure 1-4 ......... NRCS Soil Map 2.0 Conditions and Requirements Summary ................................................................................. 2-1 Core Requirements .......................................................................................................... 2-1 2.1 2.1.1 CR 1 – Discharge at the Natural Location .......................................................... 2-1 2.1.2 CR 2 – Offsite Analysis ....................................................................................... 2-1 2.1.3 CR 3 – Flow Control ............................................................................................ 2-1 2.1.4 CR 4 – Conveyance System ............................................................................... 2-1 2.1.5 CR 5 – Construction Stormwater Pollution Prevention ....................................... 2-1 2.1.6 CR 6 – Maintenance and Operations ................................................................. 2-1 2.1.7 CR 7 – Financial Guarantees and Liability ......................................................... 2-1 2.1.8 CR 8 – Water Quality Facilities ........................................................................... 2-2 2.1.9 CR 9 – Onsite Best Management Practices (BMPs) .......................................... 2-2 2.1.10 SR 1 – Other Adopted Area-Specific Requirements........................................... 2-3 2.1.11 SR 2 – Flood Hazard Area Delineation ............................................................... 2-3 2.1.12 SR 3 – Flood Protection Facilities ....................................................................... 2-3 2.1.13 SR 4 – Source Controls ...................................................................................... 2-3 2.1.14 SR 5 – Oil Control ............................................................................................... 2-3 2.1.15 SR 6 – Aquifer Protection Area ........................................................................... 2-3 Section 2.0 Figures Figure 2-1 ......... FEMA Map Figure 2-2 ......... Groundwater Protection Areas 3.0 Offsite Analysis ........................................................................................................................... 3-1 Task 1 – Study Area Definition and Maps........................................................................ 3-1 3.1 Task 2 – Resource Review .............................................................................................. 3-1 3.2 Task 3 – Field Inspection ................................................................................................. 3-1 3.3 Task 4 – Drainage System Description and Problem Descriptions ................................. 3-1 3.4 Technical Information Report ii Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 3.0 Figures Figure 3-1 ......... Downstream Drainage Map 4.0 Flow Control and Water Quality Facility Analysis and Design ............................................... 4-1 Flow Control ..................................................................................................................... 4-1 4.1 4.1.1 Existing Site Hydrology (Part A) .......................................................................... 4-1 4.1.2 Developed Site Hydrology (Part B) ..................................................................... 4-1 4.1.3 Performance Standards (Part C) ........................................................................ 4-1 4.1.4 Flow Control System (Part D) ............................................................................. 4-2 4.1.5 Water Quality System (Part E) ............................................................................ 4-2 Section 4.0 Figures Figure 4-1 ......... Flow Control Application Map Figure 4-2 ......... WWHM Report 5.0 Conveyance System Analysis and Design ............................................................................... 5-1 6.0 Special Reports and Studies ..................................................................................................... 6-1 Section 6.0 Figures Figure 6-1 ......... Geotechnical Report 7.0 Other Permits .............................................................................................................................. 7-1 8.0 CSWPPP Analysis and Design .................................................................................................. 8-1 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant .................................... 9-1 10.0 Operations and Maintenance Plan .......................................................................................... 10-1 11.0 Conclusion ................................................................................................................................. 11-1 Technical Information Report iii Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendices Appendix A Operations and Maintenance Manual Appendix B Construction Stormwater Pollution Prevention Plan (CSWPPP) Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 1 Project Overview Technical Information Report 1-1 Northwest Gourmet Freezer Addition AHBL No. 2160966.10 1.0 Project Overview Purpose and Scope 1.1 This report accompanies the civil engineering plans and documents for the Northwest Gourmet Freezer Addition project located at 600 SW 7th Street in the city of Renton. The site is located on Parcel No. 1823059254. The project proposes a 6,386-square foot freezer addition placed over the existing loading dock area against the existing 66,786-square foot building. A 300-square foot concrete freezer compressor pad surrounded by 612 square feet of gravel will be placed outside the building. The project site is approximately 5.01 acres in size. Stormwater management is to comply with the 2016 King County Surface Water Design Manual (KCSWDM), as amended by the City of Renton, the 2016 City of Renton Surface Water Design Manual (CRSWDM). Existing Conditions 1.2 The 5.01-acre site is currently occupied by Northwest Gourmet Food Products, Inc. The site contains two existing buildings, a 66,786-square foot food processing plant/office building and a 1,680-square foot storage shed. The main food processing building has loading docks along the east side, along with a paved area used for truck maneuvering. The site includes a parking lot to the south and west of the main building, a drive aisle along the north side, and a landscape/lawn area to the southeast. The northernmost portion of the site near the BNSF Railway Co. (BNSF) railroad consists of dense trees. The site is relatively flat. Runoff from the site is collected by the existing private onsite storm drainage system and discharged into the public storm drainage system within SW 7th Street. An existing Filterra unit located offsite is used to provide treatment before discharging into the Black River, approximately 0.51 mile downstream from the site. The site is bordered by a railroad owned by BNSF to the north, Harper Engineering to the west, SW 7th Street to the south, and Puget Sound Electrical JATC to the east beyond a right-of-way owned by BNSF. Refer to Figure 1-2 for the Vicinity Map. Per the Natural Resources Conservation Service (NRCS) Web Soil Survey, the majority of the site consists of Woodinville Silt Loam. The typical profile for this soil type comprises silt loam at a depth of 0 to 7 inches, silty clay loam at a depth of 7 to 15 inches, and stratified muck to silt loam at a depth of 15 to 60 inches. The soil is described as poorly drained, with approximately 0 to 12 inches of depth to the water table. The capacity of the most limiting soil layer is estimated to be between 0.20 inch per hour and 0.57 inch per hour, and is located more than 80 inches below the existing grade. The soil is classified as Hydrologic Soil Group C/D and is rated as a hydric soil. Refer to Figure 1-4 for the NRCS Soil Map. The existing drainage patterns have been analyzed and are discussed in detail in the Level One Downstream Analysis (see Section 3.0). Post-Development Conditions 1.3 The proposed project plans to remove a portion of the existing paved loading dock area on the east side of the building and construct a 6,386-square foot freezer addition. The proposed building addition will be located entirely over an area that was previously impervious. Stormwater runoff from the building addition roof will discharge onto splash blocks and will be collected by the existing private storm drainage system. The proposed 300-square foot compressor pad and 612-square foot gravel area to the south of the building addition will utilize basic dispersion sheet flow to discharge into the existing lawn area to the south. Refer to Figure 1-3 for the Permit Set. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 1.0 Figures Figure 1-1 ......... TIR Worksheet Figure 1-2 ......... Vicinity Map Figure 1-3 ......... Permit Set Figure 1-4 ......... NRCS Soil Map Mike Gilroy 600 SW 7th Street Renton, WA 98057-2916 Matt Weber, PE AHBL (253) 383-2422 NW Gourmet Foods - Freezer Addition 18 23 N 05 E June 13, 2018 600 SW 7th Street Renton, WA 98057-2916 June 13, 2018 Black River Drainage Basin Valley Peak Flow Rate Control Standard and Enhanced Basic Water Quality N/A 15% to 40% slope along north edge of property Most of site is in a seismic hazard area Wo 0% to 2%N/A Existing fill and alluvial soils cannot support infiltration SW 7th Street Public Storm Drainage System 1 TBD N/A Peak Rate Flow Control Standard June 6, 2018 #2 described in Section 1.2.3.1 N/A Commercial Roof downspouts, conveyance pipes, and catch basins #1 - Surface Area Exemption described in Section 1.2.8 N/A N/A NW Gourmet Freezer Addition Project #2160966.10 Vicinity Map Figure 1-2 SITE N2215 N. 30th Street, #300 Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX www.ahbl.com EXISTING BUILDING 66,786 SF SL EXISTING BUILDING 1,680 SF FF CL CONSTRUCTION ENTRANCE REMOVE ASPHALT PAVEMENT PROTECT EXISTING LAWN IPREMOVE CONCRETE PAVEMENT IP EXISTING CATCH BASIN COORDINATE PAVEMENT REMOVAL LIMITS WITH FOUNDATION PLAN. REMOVE PAVEMENT AS NECESSARY.Sheet No.Designed by:Drawn by:Checked by:Sheet Title:Revisions:Issue Set & Date:Client:Job No.of Sheets123Project Title:535 DOCK ST, SUITE 211, TACOMA, WA 98402TEL: 253.284.9680 FAX:253.284.9681WWW.TAHOMADESIGNGROUP.COMTAHOMADESIGN GROUPNorthwest Gourmet Foods - Freezer Addition 600 SW 7th St, Renton, WA 98057 Northwest Gourmet FoodsFreezer AdditionNorthwest Gourmet Foods600 SW 7th St, Renton, WA 98057Mike Gilroy (425) 793-5001Issue For ClientReview9/4/20182160966.10TESC ANDDEMOLITION PLANTDWTDWSTKC1.02215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB TACOMA SEATTLE SPOKANE TRI-CITIES CONSTRUCTION SEQUENCE 1.HOLD THE PRE-CONSTRUCTION MEETING WITH THE CITY OF RENTON. IDENTIFY REQUIRED INSPECTIONS. 2.POST SIGN WITH NAME AND PHONE NUMBER OF ESC SUPERVISOR (MAY BE CONSOLIDATED WITH THE REQUIRED NOTICE OF CONSTRUCTION SIGN). 3.FLAG OR FENCE CLEARING AND CONSTRUCTION LIMITS. 4.INSTALL INLET SEDIMENT PROTECTION AS SHOWN ON PLANS. 5.UTILIZE THE EXISTING EAST DRIVEWAY FOR STABILIZED CONSTRUCTION ACCESS. SWEEP ENTRANCE DAILY. 6.INSTALL FILTER FABRIC FENCE AS SHOWN ON PLANS. 7.SAWCUT AND REMOVE EXISTING ASPHALT PAVEMENT AS SHOWN ON PLANS. 8.CONSTRUCT BUILDING ADDITION AND CONCRETE PAD FOR COMPRESSOR PER ARCHITECTURAL PLANS. 9.MAINTAIN EROSION CONTROL MEASURES IN ACCORDANCE WITH CITY OF RENTON STANDARDS AND MANUFACTURER'S RECOMMENDATIONS. 10.RELOCATE EROSION CONTROL MEASURES OR INSTALL NEW MEASURES SO THAT, AS SITE CONDITIONS CHANGE, THE EROSION AND SEDIMENT CONTROL IS ALWAYS IN ACCORDANCE WITH THE CITY OF RENTON EROSION AND SEDIMENT CONTROL STANDARDS. 11.COVER ALL AREAS THAT WILL BE UNWORKED FOR MORE THAN SEVEN DAYS DURING THE DRY SEASON OR TWO DAYS DURING THE WET SEASON WITH STRAW, WOOD FIBER MULCH, COMPOST, PLASTIC SHEETING, OR EQUIVALENT. 12.STABILIZE ALL AREAS WITHIN SEVEN DAYS OF REACHING FINAL GRADE. 13.SEED, SOD, STABILIZE, OR COVER ANY AREAS TO REMAIN UNWORKED FOR MORE THAN 30 DAYS. 14.UPON COMPLETION OF THE PROJECT, STABILIZE ALL DISTURBED AREAS AND REMOVE BMPS, IF APPROPRIATE, UPON APPROVAL OF THE OWNER, ENGINEER, AND CITY OF RENTON INSPECTOR. 1.PROVIDE TEMPORARY EROSION CONTROL MEASURES AS SHOWN ON PLANS. CONTRACTOR IS RESPONSIBLE FOR MAINTAINING AND ADJUSTING EROSION CONTROL FACILITIES AS SITE CONDITIONS CHANGE. REFER TO THE T.E.S.C. NOTES AND DETAILS ON SHEET C1.1. 2.CONTRACTOR SHALL DESIGNATE A WASHINGTON STATE CERTIFIED EROSION AND SEDIMENT CONTROL LEAD (CESCL) WHO WILL BE ON-SITE OR ON CALL AT ALL TIMES. THE EROSION CONTROL LEAD SHALL HAVE THE AUTHORITY TO IMPLEMENT THE STORMWATER POLLUTION PREVENTION PLAN BASED ON SITE CONDITIONS WITHIN THEIR SCOPE. IF THE METHODS INDICATED FOR EROSION AND SEDIMENT CONTROL ARE NOT ADEQUATE, THE CESCL SHALL IMPLEMENT ADDITIONAL METHODS AS REQUIRED. 3.CONTRACTOR SHALL IMPLEMENT AND CHANGE EROSION CONTROL MEASURES AS NECESSITATED BY CONSTRUCTION ACTIVITIES. 4.CONTRACTOR SHALL MAINTAIN BMP C150: MATERIALS ON HAND, ON-SITE IN AN AREA EASILY ACCESSIBLE. 5.CONTRACTOR TO FOLLOW BMP C153: MATERIAL DELIVERY, STORAGE AND CONTAINMENT IN THE STORAGE OF HAZARDOUS MATERIALS ONSITE. TESC NOTES 1.DEMOLITION: IT IS THE INTENT UNDER THE WORK OF THIS CONTRACT TO INCLUDE, BUT NOT LIMITED TO, THE DEMOLITION OF ALL EXISTING PAVING, AND OTHER EXISTING SITE IMPROVEMENTS INCLUDING THE UNDERGROUND COMPONENTS AS CLARIFIED BY THIS DRAWING. IT IS THE CONTRACTOR'S RESPONSIBILITY TO FULLY REVIEW THE SITE CONDITIONS AND TO CORRELATE THESE OBSERVATIONS WITH THE PROJECT WORK AND INCLUDE ALL NECESSARY DEMOLITION, WHETHER SHOWN OR NOT, AND INCLUDE ALL SUCH COSTS IN THE SCOPE OF WORK. 2.CLEARING: IT IS THE INTENT UNDER THE WORK OF THIS CONTRACT TO CONDUCT ALL CLEARING NECESSARY TO BE ABLE TO COMPLETE ALL THE WORK OF THIS PROJECT. 3.CONTRACTOR SHALL LEGALLY DISPOSE ALL DEMOLISHED AND REMOVED MATERIALS OFF THE OWNER'S PROPERTY UNLESS INDICATED OTHERWISE. 4.IT IS THE RESPONSIBILITY OF THE CONTRACTOR TO COMPLETELY COORDINATE UTILITY DEMOLITION WITH NEW CONSTRUCTION. CONTRACTOR SHALL ENSURE THAT ADEQUATE FIRE PROTECTION IN ACCORDANCE WITH THE FIRE MARSHAL'S REQUIREMENTS IS PROVIDED FOR EXISTING BUILDINGS. 5.ALL WORK SHALL BE CONTAINED WITHIN THE CONSTRUCTION LIMITS SHOWN ON THIS DRAWING. NO ADJOINING AREAS SHALL BE DISTURBED BY CONSTRUCTION ACTIVITIES. 6.CONTRACTOR TO PROVIDE ADEQUATE MEASURES TO MINIMIZE THE AMOUNT OF SEDIMENT TRANSPORTED ONTO PAVED ROADS FROM MOTOR VEHICLES LEAVING THE PROJECT SITE. DEPOSITED SEDIMENT SHALL BE CLEANED EVERY DAY BY SHOVELING OR SWEEPING. WATER CLEANING SHALL ONLY BE DONE AFTER THE AREA HAS BEEN SHOVELED OUT OR SWEPT. 7.CONTRACTOR TO PROTECT EXISTING UTILITIES UNLESS OTHERWISE NOTED. DEMOLITION NOTES FILTER FABRIC FENCE CLEARING LIMITS FF CL INLET SEDIMENT PROTECTION ASPHALT PAVEMENT REMOVAL CONCRETE PAVEMENT REMOVAL TESC & DEMOLITION LEGEND SAWCUT LINESL IP 1 C1.1 2 C1.1GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 N PROTECT EXISTING CATCH BASIN SW 7TH STREET EXISTING BUILDING 66,786 SF BUILDING ADDITION 6,386 SF EXISTING BUILDING 1,680 SF CHAIN LINK FENCE REFER TO ARCHITECTURAL STAIR REFER TO ARCHITECTURAL FREEZER COMPRESSOR ON 30' x 10' CONCRETE PAD. REFER TO MECHANICAL AND ARCHITECTURAL. ROOF DOWNSPOUT PROVIDE SPLASH BLOCK TO EXISTING PAVEMENT ROOF DOWNSPOUT PROVIDE SPLASH BLOCK TO EXISTING PAVEMENT MATCH EXISTING PAVEMENT ELEVATION EXISTING CATCH BASIN EXISTING CATCH BASIN Sheet No.Designed by:Drawn by:Checked by:Sheet Title:Revisions:Issue Set & Date:Client:Job No.of Sheets123Project Title:535 DOCK ST, SUITE 211, TACOMA, WA 98402TEL: 253.284.9680 FAX:253.284.9681WWW.TAHOMADESIGNGROUP.COMTAHOMADESIGN GROUPNorthwest Gourmet Foods - Freezer Addition 600 SW 7th St, Renton, WA 98057 Northwest Gourmet FoodsFreezer AdditionNorthwest Gourmet Foods600 SW 7th St, Renton, WA 98057Mike Gilroy (425) 793-5001Issue For ClientReview9/4/20182160966.10DRAINAGE ANDSURFACING PLANTDWTDWSTKC1.12215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB TACOMA SEATTLE SPOKANE TRI-CITIES GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 N ASPHALT PAVEMENT CONCRETE PAVEMENT (PER STRUCTURAL) SURFACING LEGEND 3 C1.1 SW 7TH STREET REFER TO ARCHITECTURAL PLANS FOR HORIZONTAL CONTROL INFORMATION. STORMWATER RUNOFF FROM THE BUILDING ROOF WILL SPLASH BLOCK ONTO PAVEMENT AND DRAIN TO EXISTING CATCH BASINS. STORMWATER RUNOFF FROM THE COMPRESSOR PAD AND GRAVEL WILL SHEET FLOW TO THE EXISTING LAWN AREA, USING BASIC DISPERSION. NOTE PROVIDE GRAVEL SURFACING INSIDE CHAIN LINK FENCE MATCH EXISTING FINISH FLOOR AREA DISTURBED:7,632 SF REPLACED IMPERVIOUS SURFACE:6,386 SF (BUILDING) 334 SF (PAVEMENT) NEW IMPERVIOUS SURFACE:300 SF (COMPRESSOR PAD) 612 SF (GRAVEL) PROJECT STATISTICS Sheet No.Designed by:Drawn by:Checked by:Sheet Title:Revisions:Issue Set & Date:Client:Job No.of Sheets123Project Title:535 DOCK ST, SUITE 211, TACOMA, WA 98402TEL: 253.284.9680 FAX:253.284.9681WWW.TAHOMADESIGNGROUP.COMTAHOMADESIGN GROUPNorthwest Gourmet Foods - Freezer Addition 600 SW 7th St, Renton, WA 98057 Northwest Gourmet FoodsFreezer AdditionNorthwest Gourmet Foods600 SW 7th St, Renton, WA 98057Mike Gilroy (425) 793-5001Issue For ClientReview9/4/20182160966.10NOTES AND DETAILSTDWTDWSTKC1.22215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB TACOMA SEATTLE SPOKANE TRI-CITIES PROVIDE HERBICIDE TREATMENT NOTE : 1.ALL DEPTHS SHOWN ARE COMPACTED DEPTHS. 2.PREPARE SUBGRADE PER GEOTECHNICAL RECOMMMENDATIONS. COMPACTED SUBGRADE TO 95% 30" MINIMUM CRUSHED SURFACING TOP COURSE PER WSDOT STANDARD SPECIFICATION 9-03.9(3) HMA CLASS 1/2", PG 64-22 PER WSDOT STANDARD SPECIFICATION 5-04 6" 3" 1 NOT TO SCALE FILTER FABRIC FENCE 2 NOT TO SCALE INLET SEDIMENT PROTECTION 3 NOT TO SCALE ASPHALT PAVEMENT SECTION Soil Map—King County Area, Washington (NW Gourmet Foods) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/12/2018 Page 1 of 352579005258000525810052582005258300525840052585005257900525800052581005258200525830052584005258500557800557900558000558100558200558300558400558500558600558700558800558900559000 557800 557900 558000 558100 558200 558300 558400 558500 558600 558700 558800 558900 559000 47° 28' 40'' N 122° 14' 2'' W47° 28' 40'' N122° 13' 0'' W47° 28' 17'' N 122° 14' 2'' W47° 28' 17'' N 122° 13' 0'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 150 300 600 900 Feet 0 50 100 200 300 Meters Map Scale: 1:3,460 if printed on B landscape (17" x 11") sheet. Soil Map may not be valid at this scale. Site 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 13, Sep 7, 2017 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 31, 2013—Oct 6, 2013 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. Soil Map—King County Area, Washington (NW Gourmet Foods) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/12/2018 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI BeC Beausite gravelly sandy loam, 6 to 15 percent slopes 31.1 22.5% BeD Beausite gravelly sandy loam, 15 to 30 percent slopes 4.9 3.5% Ur Urban land 72.1 52.1% Wo Woodinville silt loam 30.2 21.9% Totals for Area of Interest 138.3 100.0% Soil Map—King County Area, Washington NW Gourmet Foods Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/12/2018 Page 3 of 3 Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 2 Conditions and Requirements Summary Technical Information Report Northwest Gourmet Freezer Addition 2-1 AHBL No. 2160966.10 2.0 Conditions and Requirements Summary Core Requirements 2.1 2.1.1 CR 1 – Discharge at the Natural Location The site consists of one sub-basin and one Threshold Discharge Area (TDA). Runoff from the site is collected by the existing private onsite storm drainage system and discharged into the public storm drainage system within SW 7th Street. The natural discharge location will be maintained in the developed conditions. 2.1.2 CR 2 – Offsite Analysis A level one downstream analysis is included in Section 3.0 below, including the defined and mapped study area, available information on the study area, and results from field inspections. 2.1.3 CR 3 – Flow Control The project is located in a Peak Flow Rate Control Standard area (refer to Figure 4-1). This flow control standard requires the 2-year, 10-year, and 100-year peak flow rates under developed conditions to be equal to or less than the peak flow rates under existing conditions. However, the target surfaces within the TDA will generate an increase in the 100-year peak flow that is less than 0.15 cfs. Therefore, the exception described in Section 1.2.3.1 of the CRSWDM applies to the project, and no flow control facilities are required with the proposed improvements. Flow control is discussed in further detail in Section 4.0, Flow Control and Water Quality Facility Analysis and Design. 2.1.4 CR 4 – Conveyance System There are no new conveyance systems proposed with the site improvements. The existing onsite private storm drainage system will be utilized to collect stormwater runoff from the site. Since there is only a 0.0112 cfs increase in the 100-year peak flow for the project, the existing drainage system does not need to be analyzed for conveyance capacity, as described in Section 1.2.4.2 of the CRSWDM. Refer to Section 5.0 for more information. 2.1.5 CR 5 – Construction Stormwater Pollution Prevention Onsite land disturbance will consist of sawcutting, demolition, and removal of existing asphalt and concrete pavement at the location of the building addition, as well as removal of topsoil and resurfacing at the location of the freezer compressor pad. A Construction Stormwater Pollution Prevention Plan (CSWPPP) is attached to this report as Appendix B. 2.1.6 CR 6 – Maintenance and Operations Maintenance and operations of all private drainage systems and onsite BMPs is the responsibility of the owner. An Operations and Maintenance Manual is provided as Appendix A. 2.1.7 CR 7 – Financial Guarantees and Liability All financial guarantees and liability requirements will be met by the owner. A Drainage Facilities Restoration and Site Stabilization Financial Guarantee will be provided, as necessary. Technical Information Report Northwest Gourmet Freezer Addition 2-2 AHBL No. 2160966.10 2.1.8 CR 8 – Water Quality Facilities Since the project proposes to remove existing pollution generating impervious surfaces (PGIS) and replace them with non-pollution-generating roof area, the site does not require the addition of water quality facilities. The overall developed site will have a net decrease in the PGIS area, meeting the surface area exemption from the requirement stated in Section 1.2.8 of the CRSWDM. The existing Filterra unit downstream will provide treatment for the developed site. 2.1.9 CR 9 – Onsite Best Management Practices (BMPs) Since the overall site area is greater than 22,000 square feet, the site is classified as a Large Lot per Section 1.2.9.2 of the CRSWDM. The proposed project will meet the Large Lot BMP Requirements outlined in Section 1.2.9.2.2 of the CRSWDM. Below is a discussion of the list approach for each type of surface proposed on the site. Landscape Areas  Post Construction Soil Quality and Depth will be used. Impervious Areas  Full Dispersion is not feasible because there are no native vegetated areas downslope from the proposed building addition. Additionally, the proposed impervious area is greater than 15 percent of the onsite native vegetated surface area.  Full Infiltration of Roof Runoff is not feasible since the existing fill and alluvial soils cannot support infiltration.  Full Infiltration and Limited Infiltration are not feasible because the existing fill and alluvial soils cannot support infiltration.  Bioretention per Onsite BMP standards is not feasible because the existing fill and alluvial soils cannot support infiltration.  Permeable Pavement is not feasible because the existing fill and alluvial soils cannot support infiltration.  Basic Dispersion is not feasible for the 6,386-square foot roofed area because each splash block is limited to 700 square feet of tributary roofed area, and the gravel-filled trenches are limited to 3,500 square feet of tributary roofed area. However, basic dispersion using sheet flow can be applied to the 300-square foot concrete compressor pad and the 612-square foot gravel area since there is adequate lawn area to be used as a vegetative flow path.  The Reduced Impervious Surface Credit, Native Growth Retention Credit, and Tree Retention Credit are not feasible for this site.  Native Growth Retention Credit and Tree Retention Credit are not feasible because there is no existing native vegetation or trees onsite.  Perforated Pipe Connection is not feasible because the existing fill and alluvial soils cannot support infiltration. Technical Information Report Northwest Gourmet Freezer Addition 2-3 AHBL No. 2160966.10 2.1.10 SR 1 – Other Adopted Area-Specific Requirements To our knowledge, there are no adopted area-specific requirements that are applicable to the project site. 2.1.11 SR 2 – Flood Hazard Area Delineation Flood Insurance Rate Map 53033C0976 F, Panel 976 of 1725, was consulted for this project and shows the project site within the Zone X area, which is described as areas determined to be outside of the 500-year floodplain. Refer to Figure 2-1 of this section for the Flood Insurance Rate Map. 2.1.12 SR 3 – Flood Protection Facilities The project site does not contain, nor is it adjacent to, any existing flood protection facilities. Project improvements do not include flood protection measures. 2.1.13 SR 4 – Source Controls The proposed project is classified as a commercial site. Water quality source controls applicable to the project site shall be evaluated and applied, as described in the King County Stormwater Pollution Prevention Manual (KCSWPPM) and Renton Municipal Code IV. Structural source controls (such as car wash pads and dumpster area roofing) are not proposed for this project. However, non-structural source control measures, such as plastic covering for storage piles and isolating areas where pollutants are used or stored, shall be implemented to the maximum extent feasible. Source control and erosion and sediment control measures during construction are included in the CSWPPP attached as Appendix B. 2.1.14 SR 5 – Oil Control The project is not considered a high-use site; therefore, it is not subject to oil control requirements. 2.1.15 SR 6 – Aquifer Protection Area According to the City of Renton Public Works Department Groundwater Protection Areas map, Reference 15-B of the CRSWDM, the site is not located within an aquifer protection area. Refer to Figure 2-2 for the above referenced map. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 2.0 Figures Figure 2-1 ......... FEMA Map Figure 2-2 ......... Groundwater Protection Areas Site Site Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 3 Offsite Analysis Technical Information Report Northwest Gourmet Freezer Addition 3-1 AHBL No. 2160966.10 3.0 Offsite Analysis Task 1 – Study Area Definition and Maps 3.1 There are no upstream tributary areas contributing stormwater to the onsite basin area. Task 2 – Resource Review 3.2 The following resources were reviewed to determine if there are any existing or potential problems in the study area:  Adopted Basin Plans: The project lies within the Black River Drainage Basin. Requirements for the Black River Drainage Basin will be followed where applicable.  Offsite Analysis Reports: AHBL staff has not located offsite analysis reports for projects near the site.  FEMA Map: Flood Insurance Rate Map 53033C0976 F, Panel 976 of 1725, dated May 16, 1995 (see Figure 2-1), indicates that the project site lies outside the categorized flood zones.  City of Renton Effective FEMA Flood Insurance Rate Map: The project site is not located in a Flood Hazard Zone (see Figure 3-1).  City of Renton online GIS Map. Task 3 – Field Inspection 3.3 A field inspection of the downstream drainage system was performed on June 6, 2018. There were no visible signs of downstream drainage problems. The onsite and offsite conveyance systems appear to be functioning properly. Task 4 – Drainage System Description and Problem Descriptions 3.4 Runoff from the site discharges to the public storm system within SW 7th Street. The public storm system consists of a 60-inch diameter reinforced concrete pipe flowing west. At the intersection of SW 7th Street and Naches Avenue SW, the system begins to run north, where it discharges into the Black River approximately 0.51 mile downstream from the site. There are no known signs of flooding, overtopping, or erosion. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 3.0 Figures Figure 3-1 ......... Downstream Drainage Map 4,800800 Downstream Drainage Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes 06/13/2018 Legend 544 0 272 544 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Parcels Network Structures Inlet Manhole Utility Vault Unknown Structure Control Structure Pump Station Discharge Point Water Quality Detention Facilities Pond Tank Vault Wetland Stormwater Main Culvert Open Drains Facility Outline Private Network Structures Inlet Manhole Utility Vault Unknown Structure Private Control Structure Private Discharge Point Private Water Quality Private Detention Facilities Pond Tank Vault Wetland Private Pipe Private Culvert Private Open Drains Private Facility Outline Fence2,694 .3 f t Outfall to the Black River Site Public Storm Main 60" Diameter Reinforced Concrete Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 4 Flow Control and Water Quality Facility Analysis and Design Technical Information Report Northwest Gourmet Freezer Addition 4-1 AHBL No. 2160966.10 4.0 Flow Control and Water Quality Facility Analysis and Design Flow Control 4.1 4.1.1 Existing Site Hydrology (Part A) The 5.01-acre site is currently occupied by Northwest Gourmet Food Products, Inc. The site contains two existing buildings, a 66,786-square foot food processing plant/office building and a 1,680-square foot storage shed. The main food processing building has loading docks along the east side, along with a paved area used for truck maneuvering. The site includes a parking lot to the south and west of the main building, a drive aisle along the north side, and a landscape/lawn area to the southeast. The northernmost portion of the site near the BNSF Railway Co . (BNSF) railroad consists of dense trees. The site is relatively flat. Runoff from the site is collected by the existing private onsite storm drainage system and discharged into the public storm drainage system within SW 7th Street. An existing Filterra unit located offsite is used to provide treatment before discharging into the Black River, approximately 0.51 mile downstream from the site. 4.1.2 Developed Site Hydrology (Part B) The proposed project plans to remove a portion of the existing paved loading dock a rea on the east side of the building and construct a 6,386-square foot freezer addition. The proposed building addition will be located entirely over an area that was previously impervious. Stormwater runoff from the building addition roof will discharge onto splash blocks and will be collected by the existing private storm drainage system. The proposed 300-square foot compressor pad and 612-square foot gravel area to the south of the building addition will utilize basic dispersion sheet flow to discharge into the existing lawn area to the south. 4.1.3 Performance Standards (Part C) Area-Specific Flow Control Facility Standard The project site is located within a Peak Rate Flow Control Standard area. This standard requires that the proposed project site match existing peak flow rates for the 2-, 10-, and 100-year stormwater events (see Figure 4-1). The exception to this rule applies when the increase in the 100-year peak flow is no more than 0.15 cfs (modeled using 15-minute time steps). Conveyance System Capacity Standards Per Section 1.2.4.2 of the CRSWDM, existing systems that will not experience a change in flow characteristics (e.g., peak flows or volume of flows) as a result of the proposed project need not be analyzed for conveyance capacity. If the existing system experiences a change in flow characteristics, then the system must be analyzed to demonstrate that it has sufficient capacity to convey and contain the 25 -year peak flow, assuming developed conditions. The applicant must also demonstrate that the 100-year peak flow to the existing system will not create or aggravate a severe flooding problem or severe erosion problem, as described in Core Requirement #2, Section 1.2.2 of the CRSWDM. Water Quality Treatment Menu In accordance with the 2016 CRSWDM, onsite flows must be treated to specifications provided by the Enhanced Basic Water Quality standards. The goal of this treatment menu is to reduce total suspended solids (TSS) by 80 percent and to reduce zinc concentration by 50 percent for a typical rainfall year. This requirement only applies to new and replaced PGIS. Technical Information Report Northwest Gourmet Freezer Addition 4-2 AHBL No. 2160966.10 Source Controls The proposed project is classified as a commercial site. Water quality source controls applicable to the project site shall be evaluated and applied, as described in the KCSWPPM and Renton Municipal Code IV. Structural source controls (such as car wash pads and dumpster area roofing) are not proposed for this project. However, non-structural source control measures, such as plastic covering for storage piles and isolating areas where pollutants are used or stored, shall be implemented to the maximum extent feasible. Source control and erosion and sediment control measures during construction are included in the CSWPPP attached as Appendix B. Oil Controls The project is not considered a high-use site; therefore, it is not subject to oil control requirements. 4.1.4 Flow Control System (Part D) The project is located in a Peak Flow Rate Control Standard area (refer to Figure 4-1). This flow control standard requires the 2-year, 10-year, and 100-year peak flow rates under developed conditions to be equal to or less than the peak flow rates under existing conditions. However, the target surfaces within the TDA will generate an increase in the 100-year peak flow that is less than 0.15 cfs. Therefore, the exception described in Section 1.2.3.1 of the CRSWDM applies to the project, and no flow control facilities are required with the proposed improvements. The WWHM Report is included as Figure 4-2. 4.1.5 Water Quality System (Part E) Since the project proposes to remove existing PGIS and replace them with non -pollution- generating roof area, the site does not require the addition of water quality facilities. The overall developed site will have a net decrease in the PGIS area, meeting the surface area exemption from the requirement stated in Section 1.2.8 of the CRSWDM. The existing Filterra unit downstream will provide treatment for the developed site. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 4.0 Figures Figure 4-1 ......... Flow Control Application Map Figure 4-2 ......... WWHM Report Site WWHM2012 PROJECT REPORT 20180830 100-year peak flow 8/30/2018 11:53:27 AM Page 2 General Model Information Project Name:20180830 100-year peak flow Site Name:Northwest Gourmet Freezer Addition Site Address:600 SW 7th Street City:Renton Report Date:8/30/2018 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2018/03/08 Version:4.2.14 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 20180830 100-year peak flow 8/30/2018 11:53:27 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.020937 Pervious Total 0.020937 Impervious Land Use acre PARKING FLAT 0.15427 Impervious Total 0.15427 Basin Total 0.175207 Element Flows To: Surface Interflow Groundwater 20180830 100-year peak flow 8/30/2018 11:53:27 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.1466 PARKING FLAT 0.028604 Impervious Total 0.175204 Basin Total 0.175204 Element Flows To: Surface Interflow Groundwater 20180830 100-year peak flow 8/30/2018 11:53:27 AM Page 5 Routing Elements Predeveloped Routing 20180830 100-year peak flow 8/30/2018 11:53:27 AM Page 6 Mitigated Routing 20180830 100-year peak flow 8/30/2018 11:53:27 AM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.020937 Total Impervious Area:0.15427 Mitigated Landuse Totals for POC #1 Total Pervious Area:0 Total Impervious Area:0.175204 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.060161 5 year 0.07645 10 year 0.08757 25 year 0.102045 50 year 0.11316 100 year 0.124574 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.066799 5 year 0.084375 10 year 0.096317 25 year 0.111807 50 year 0.123662 100 year 0.135806 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.079 0.087 1950 0.083 0.093 1951 0.049 0.054 1952 0.043 0.048 1953 0.046 0.052 1954 0.049 0.054 1955 0.055 0.062 1956 0.054 0.061 1957 0.063 0.069 1958 0.050 0.055 20180830 100-year peak flow 8/30/2018 11:54:00 AM Page 8 1959 0.050 0.057 1960 0.051 0.056 1961 0.053 0.059 1962 0.046 0.051 1963 0.051 0.057 1964 0.049 0.056 1965 0.065 0.071 1966 0.042 0.047 1967 0.073 0.082 1968 0.084 0.093 1969 0.059 0.064 1970 0.056 0.062 1971 0.067 0.074 1972 0.071 0.077 1973 0.041 0.046 1974 0.061 0.068 1975 0.069 0.078 1976 0.048 0.052 1977 0.050 0.057 1978 0.061 0.069 1979 0.084 0.095 1980 0.079 0.085 1981 0.063 0.070 1982 0.089 0.098 1983 0.071 0.080 1984 0.045 0.051 1985 0.063 0.070 1986 0.054 0.060 1987 0.083 0.093 1988 0.050 0.057 1989 0.062 0.071 1990 0.113 0.119 1991 0.089 0.095 1992 0.045 0.050 1993 0.039 0.043 1994 0.042 0.047 1995 0.055 0.062 1996 0.061 0.066 1997 0.058 0.064 1998 0.058 0.065 1999 0.121 0.133 2000 0.060 0.066 2001 0.064 0.073 2002 0.078 0.085 2003 0.060 0.066 2004 0.113 0.124 2005 0.052 0.057 2006 0.046 0.050 2007 0.106 0.116 2008 0.087 0.093 2009 0.076 0.086 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.1210 0.1326 2 0.1129 0.1241 3 0.1127 0.1190 20180830 100-year peak flow 8/30/2018 11:54:00 AM Page 9 4 0.1058 0.1160 5 0.0893 0.0984 6 0.0886 0.0951 7 0.0871 0.0951 8 0.0841 0.0935 9 0.0835 0.0934 10 0.0828 0.0931 11 0.0827 0.0928 12 0.0793 0.0865 13 0.0792 0.0863 14 0.0777 0.0853 15 0.0761 0.0846 16 0.0734 0.0816 17 0.0713 0.0801 18 0.0708 0.0780 19 0.0687 0.0766 20 0.0669 0.0742 21 0.0646 0.0725 22 0.0643 0.0708 23 0.0627 0.0707 24 0.0626 0.0698 25 0.0625 0.0696 26 0.0622 0.0695 27 0.0615 0.0688 28 0.0614 0.0677 29 0.0605 0.0660 30 0.0604 0.0659 31 0.0597 0.0658 32 0.0588 0.0648 33 0.0584 0.0645 34 0.0578 0.0640 35 0.0561 0.0622 36 0.0554 0.0619 37 0.0552 0.0616 38 0.0544 0.0606 39 0.0537 0.0604 40 0.0532 0.0587 41 0.0517 0.0569 42 0.0515 0.0568 43 0.0509 0.0567 44 0.0501 0.0566 45 0.0498 0.0565 46 0.0498 0.0557 47 0.0496 0.0555 48 0.0494 0.0555 49 0.0493 0.0543 50 0.0490 0.0540 51 0.0476 0.0525 52 0.0460 0.0519 53 0.0459 0.0512 54 0.0455 0.0505 55 0.0455 0.0501 56 0.0450 0.0500 57 0.0426 0.0481 58 0.0424 0.0474 59 0.0415 0.0472 60 0.0409 0.0464 61 0.0386 0.0433 20180830 100-year peak flow 8/30/2018 11:54:00 AM Page 10 20180830 100-year peak flow 8/30/2018 11:54:00 AM Page 11 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.0301 1757 2577 146 Fail 0.0309 1600 2370 148 Fail 0.0318 1445 2167 149 Fail 0.0326 1302 1976 151 Fail 0.0334 1181 1794 151 Fail 0.0343 1065 1646 154 Fail 0.0351 977 1490 152 Fail 0.0360 899 1369 152 Fail 0.0368 828 1254 151 Fail 0.0376 760 1146 150 Fail 0.0385 697 1043 149 Fail 0.0393 641 965 150 Fail 0.0402 592 887 149 Fail 0.0410 553 835 150 Fail 0.0418 512 767 149 Fail 0.0427 468 720 153 Fail 0.0435 434 661 152 Fail 0.0443 403 610 151 Fail 0.0452 379 573 151 Fail 0.0460 352 540 153 Fail 0.0469 327 500 152 Fail 0.0477 306 458 149 Fail 0.0485 284 428 150 Fail 0.0494 268 405 151 Fail 0.0502 245 376 153 Fail 0.0511 228 354 155 Fail 0.0519 214 327 152 Fail 0.0527 204 311 152 Fail 0.0536 189 293 155 Fail 0.0544 176 271 153 Fail 0.0553 162 256 158 Fail 0.0561 153 239 156 Fail 0.0569 143 223 155 Fail 0.0578 137 210 153 Fail 0.0586 127 197 155 Fail 0.0595 119 184 154 Fail 0.0603 112 178 158 Fail 0.0611 107 170 158 Fail 0.0620 101 153 151 Fail 0.0628 93 145 155 Fail 0.0636 86 139 161 Fail 0.0645 83 135 162 Fail 0.0653 80 122 152 Fail 0.0662 78 113 144 Fail 0.0670 72 108 150 Fail 0.0678 67 105 156 Fail 0.0687 63 103 163 Fail 0.0695 61 95 155 Fail 0.0704 61 90 147 Fail 0.0712 56 84 150 Fail 0.0720 52 81 155 Fail 0.0729 52 72 138 Fail 0.0737 49 68 138 Fail 0.0746 46 65 141 Fail 20180830 100-year peak flow 8/30/2018 11:54:00 AM Page 12 0.0754 44 63 143 Fail 0.0762 39 62 158 Fail 0.0771 38 58 152 Fail 0.0779 33 56 169 Fail 0.0788 32 54 168 Fail 0.0796 29 53 182 Fail 0.0804 26 50 192 Fail 0.0813 25 49 196 Fail 0.0821 24 45 187 Fail 0.0829 20 43 215 Fail 0.0838 17 40 235 Fail 0.0846 16 37 231 Fail 0.0855 15 33 220 Fail 0.0863 12 32 266 Fail 0.0871 11 29 263 Fail 0.0880 11 28 254 Fail 0.0888 9 25 277 Fail 0.0897 8 23 287 Fail 0.0905 8 21 262 Fail 0.0913 8 20 250 Fail 0.0922 8 18 225 Fail 0.0930 8 16 200 Fail 0.0939 8 12 150 Fail 0.0947 8 12 150 Fail 0.0955 8 9 112 Fail 0.0964 8 9 112 Fail 0.0972 8 9 112 Fail 0.0981 8 9 112 Fail 0.0989 8 8 100 Pass 0.0997 8 8 100 Pass 0.1006 6 8 133 Fail 0.1014 6 8 133 Fail 0.1023 6 8 133 Fail 0.1031 6 8 133 Fail 0.1039 6 8 133 Fail 0.1048 6 8 133 Fail 0.1056 6 7 116 Fail 0.1064 5 7 140 Fail 0.1073 5 7 140 Fail 0.1081 4 7 175 Fail 0.1090 4 7 175 Fail 0.1098 4 7 175 Fail 0.1106 3 6 200 Fail 0.1115 3 6 200 Fail 0.1123 3 6 200 Fail 0.1132 1 6 600 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. 20180830 100-year peak flow 8/30/2018 11:54:00 AM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. 20180830 100-year peak flow 8/30/2018 11:54:00 AM Page 14 LID Report 20180830 100-year peak flow 8/30/2018 11:54:24 AM Page 15 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 20180830 100-year peak flow 8/30/2018 11:54:24 AM Page 16 Appendix Predeveloped Schematic 20180830 100-year peak flow 8/30/2018 11:54:25 AM Page 17 Mitigated Schematic 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 18 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20180830 100-year peak flow.wdm MESSU 25 Pre20180830 100-year peak flow.MES 27 Pre20180830 100-year peak flow.L61 28 Pre20180830 100-year peak flow.L62 30 POC20180830 100-year peak flow1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 11 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 19 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 11 PARKING/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 11 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 11 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 11 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 11 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 11 0 0 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 20 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 11 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 16 0.020937 COPY 501 12 PERLND 16 0.020937 COPY 501 13 IMPLND 11 0.15427 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 21 END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 22 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20180830 100-year peak flow.wdm MESSU 25 Mit20180830 100-year peak flow.MES 27 Mit20180830 100-year peak flow.L61 28 Mit20180830 100-year peak flow.L62 30 POC20180830 100-year peak flow1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 IMPLND 4 IMPLND 11 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 23 # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 4 ROOF TOPS/FLAT 1 1 1 27 0 11 PARKING/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 4 0 0 1 0 0 0 11 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 4 0 0 4 0 0 0 1 9 11 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 4 0 0 0 0 0 11 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 4 400 0.01 0.1 0.1 11 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 4 0 0 11 0 0 END IWAT-PARM3 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 24 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 4 0 0 11 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** IMPLND 4 0.1466 COPY 501 15 IMPLND 11 0.028604 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 25 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 26 Predeveloped HSPF Message File 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 27 Mitigated HSPF Message File 20180830 100-year peak flow 8/30/2018 11:54:26 AM Page 28 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2018; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 5 Conveyance System Analysis and Design Technical Information Report Northwest Gourmet Freezer Addition 5-1 AHBL No. 2160966.10 5.0 Conveyance System Analysis and Design There are no new conveyance systems proposed with the site improvements. The existing onsite private storm drainage system will be utilized to collect stormwater runoff from the site. Since there is only a 0.0112 cfs increase in the 100-year peak flow for the project, the existing drainage system does not need to be analyzed for conveyance capacity, as described in Section 1.2.4.2 of the CRSWDM. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 6 Special Reports and Studies Technical Information Report Northwest Gourmet Freezer Addition 6-1 AHBL No. 2160966.10 6.0 Special Reports and Studies A Geotechnical Engineering Report dated May 22, 2013, by E3RA, Inc. is included as Figure 6-1. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 6.0 Figures Figure 6-1 ......... Geotechnical Report Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 7 Other Permits Technical Information Report Northwest Gourmet Freezer Addition 7-1 AHBL No. 2160966.10 7.0 Other Permits A City of Renton commercial building permit may also be required for the project. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 8 CSWPPP Analysis and Design Technical Information Report Northwest Gourmet Freezer Addition 8-1 AHBL No. 2160966.10 8.0 CSWPPP Analysis and Design A CSWPPP is attached to this report as Appendix B. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 9 Bond Quantities, Facility Summaries, and Declaration of Covenant Technical Information Report Northwest Gourmet Freezer Addition 9-1 AHBL No. 2160966.10 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant The required forms will be provided, as necessary. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 10 Operations and Maintenance Plan Technical Information Report Northwest Gourmet Freezer Addition 10-1 AHBL No. 2160966.10 10.0 Operations and Maintenance Plan Maintenance and operations of all private drainage systems and onsite BMPs are the responsibility of the owner. An Operations and Maintenance Manual is provided as Appendix A. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Section 11 Conclusion Technical Information Report Northwest Gourmet Freezer Addition 11-1 AHBL No. 2160966.10 11.0 Conclusion The proposed project plans to remove a portion of the existing paved loading dock area on the east side of the building and construct a 6,386-square foot freezer addition. The proposed building addition will be located entirely over an area that was previously impervious. Stormwater runoff from the building addition roof will discharge onto splash blocks and will be collected by the existing private storm drainage system. The proposed 300-square foot compressor pad and 612-square foot gravel area to the south of the building addition will utilize basic dispersion sheet flow to discharge into the existing lawn area to the south. This report demonstrates compliance with all 9 Core Requirements and all 6 Special Requirements in the 2016 King County Surface Water Design Manual (KCSWDM), as amended by the City of Renton, the 2016 City of Renton Surface Water Design Manual (CRSWDM). This analysis is based on data and records either supplied to or obtained by AHBL. These documents are referenced within the text of the analysis. The analysis has been prepared utilizing procedures and practices within the standard accepted practices of the industry. We conclude that this project, as schematically represented, will not create any new problems within the downstream drainage system. This project will not noticeably aggravate any existing downstream problems due to either water quality or quantity. AHBL, Inc. Tyler D. Watkins, EIT Project Engineer TDW /lsk June 2018 Revised September 2018 Q:\2016\2160966\WORDPROC\Reports\20180904 Rpt (TIR) 2160966.10.docx Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendix A Operations and Maintenance Manual CITY OF RENTON SURFACE WATER DESIGN MANUAL 2017 City of Renton Surface Water Design Manual 12/12/2016 A-1 APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS This appendix contains the maintenance requirements for the following typical stormwater flow control and water quality facilities and on-site BMPs (ctrl/click the title to follow the link): No. 1 – Detention Ponds No. 2 – Infiltration Facilities No. 3 – Detention Tanks and Vaults No. 4 – Control Structure/Flow Restrictor No. 5 – Catch Basins and Manholes No. 6 – Conveyance Pipes and Ditches No. 7 – Debris Barriers (e.g., trash racks) No. 8 – Energy Dissipaters No. 9 – Fencing No. 10 – Gates/Bollards/Access Barriers No. 11 – Grounds (landscaping) No. 12 – Access Roads No. 13 – Basic Bioswale (grass) No. 14 – Wet Bioswale No. 15 – Filter Strip No. 16 – Wetpond No. 17 – Wetvault No. 18 – Stormwater Wetland No. 19 – Sand Filter Pond No. 20 – Sand Filter Vault No. 21 – Proprietary Facility Cartridge Filter Systems No. 22 – Baffle Oil/Water Separator No. 23 – Coalescing Plate Oil/Water Separator APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-2 No. 24 – Catch Basin Insert (not allowed in the city for oil control) No. 25 – Drywell BMP No. 26 – Gravel Filled Infiltration Trench BMP No. 27 – Gravel Filled Dispersion Trench BMP No. 28 – Native Vegetated Surface/Native Vegetated Landscape BMP No. 29 – Perforated Pipe Connections BMP No. 30 – Permeable Pavement BMP No. 31 – Bioretention BMP No. 32 – RainWater Harvesting BMP No. 33 – Rock Pad BMP No. 34 – Sheet Flow BMP No. 35 – Splash Block BMP No. 36 – Vegetated Roof BMP No. 37 – Rain Garden BMP No. 38 – Soil Amendment BMP No. 39 – Retained Trees No. 40 – Filterra System No. 41 – Compost Amended Vegetated Filter Strip (CAVFS) No. 42 – Media Filter Drain (MFD) No. 43 – Compost-Amended Biofiltration Swale APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-10 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the catch basin to the invert of the lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Sump of catch basin contains no sediment. Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and is structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-11 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Inlet/Outlet Pipe (cont.) Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing grate Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-12 NO. 6 – CONVEYANCE PIPES AND DITCHES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/root growth in pipe Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective coating or corrosion Protective coating is damaged; rust or corrosion is weakening the structural integrity of any part of pipe. Pipe repaired or replaced. Damaged pipes Any dent that decreases the cross section area of pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Pipe repaired or replaced. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive vegetation growth Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion damage to slopes Any erosion observed on a ditch slope. Slopes are not eroding. Rock lining out of place or missing (If applicable) One layer or less of rock exists above native soil area 5 square feet or more, any exposed native soil. Replace rocks to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-15 NO. 9 – FENCING MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Erosion or holes under fence Erosion or holes more than 4 inches high and 12-18 inches wide permitting access through an opening under a fence. No access under the fence. Wood Posts, Boards and Cross Members Missing or damaged parts Missing or broken boards, post out of plumb by more than 6 inches or cross members broken No gaps on fence due to missing or broken boards, post plumb to within 1½ inches, cross members sound. Weakened by rotting or insects Any part showing structural deterioration due to rotting or insect damage All parts of fence are structurally sound. Damaged or failed post foundation Concrete or metal attachments deteriorated or unable to support posts. Post foundation capable of supporting posts even in strong wind. Metal Posts, Rails and Fabric Damaged parts Post out of plumb more than 6 inches. Post plumb to within 1½ inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence (including post, top rails, and fabric) more than 1 foot out of design alignment. Fence is aligned and meets design standards. Missing or loose tension wire. Tension wire in place and holding fabric. Deteriorated paint or protective coating Part or parts that have a rusting or scaling condition that has affected structural adequacy. Structurally adequate posts or parts with a uniform protective coating. Openings in fabric Openings in fabric are such that an 8-inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-16 NO. 10 – GATES/BOLLARDS/ACCESS BARRIERS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Chain Link Fencing Gate Damaged or missing members Missing gate. Gates in place. Broken or missing hinges such that gate cannot be easily opened and closed by a maintenance person. Hinges intact and lubed. Gate is working freely. Gate is out of plumb more than 6 inches and more than 1 foot out of design alignment. Gate is aligned and vertical. Missing stretcher bar, stretcher bands, and ties. Stretcher bar, bands, and ties in place. Locking mechanism does not lock gate Locking device missing, no-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Openings in fabric Openings in fabric are such that an 8-inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. Bar Gate Damaged or missing cross bar Cross bar does not swing open or closed, is missing or is bent to where it does not prevent vehicle access. Cross bar swings fully open and closed and prevents vehicle access. Locking mechanism does not lock gate Locking device missing, no-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Support post damaged Support post does not hold cross bar up. Cross bar held up preventing vehicle access into facility. Bollards Damaged or missing bollards Bollard broken, missing, does not fit into support hole or hinge broken or missing. No access for motorized vehicles to get into facility. Bollards do not lock Locking assembly or lock missing or cannot be attached to lock bollard in place. No access for motorized vehicles to get into facility. Boulders Dislodged boulders Boulders not located to prevent motorized vehicle access. No access for motorized vehicles to get into facility. Evidence of vehicles circumventing boulders Motorized vehicles going around or between boulders. No access for motorized vehicles to get into facility. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-17 NO. 11 – GROUNDS (LANDSCAPING) MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trees and Shrubs Hazard tree identified Any tree or limb of a tree identified as having a potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. No hazard trees in facility. Damaged tree or shrub identified Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. No blown down vegetation or knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; dead or diseased trees removed. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-18 NO. 12 – ACCESS ROADS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet (i.e., trash and debris would fill up one standards size garbage can). Roadway drivable by maintenance vehicles. Debris which could damage vehicle tires or prohibit use of road. Roadway drivable by maintenance vehicles. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Blocked roadway Any obstruction which reduces clearance above road surface to less than 14 feet. Roadway overhead clear to 14 feet high. Any obstruction restricting the access to a 10- to 12 foot width for a distance of more than 12 feet or any point restricting access to less than a 10 foot width. At least 12-foot of width on access road. Road Surface Erosion, settlement, potholes, soft spots, ruts Any surface defect which hinders or prevents maintenance access. Road drivable by maintenance vehicles. Vegetation on road surface Trees or other vegetation prevent access to facility by maintenance vehicles. Maintenance vehicles can access facility. Shoulders and Ditches Erosion Erosion within 1 foot of the roadway more than 8 inches wide and 6 inches deep. Shoulder free of erosion and matching the surrounding road. Weeds and brush Weeds and brush exceed 18 inches in height or hinder maintenance access. Weeds and brush cut to 2 inches in height or cleared in such a way as to allow maintenance access. Modular Grid Pavement Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damaged or missing blocks/grids Access surface compacted because of broken on missing modular block. Access road surface restored so road infiltrates. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-40 NO. 28 – NATIVE VEGETATED SURFACE/NATIVE VEGETATED LANDSCAPE BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on the native vegetated surface/native vegetated landscape site. Native vegetated surface site free of any trash or debris. Vegetation Insufficient vegetation Less than two species each of native trees, shrubs, and groundcover occur in the design area. A minimum of two species each of native trees, shrubs, and groundcover is established and healthy. Poor vegetation coverage Less than 90% if the required vegetated area has healthy growth. A minimum of 90% of the required vegetated area has healthy growth. Undesirable vegetation present Weeds, blackberry, and other undesirable plants are invading more than 10% of vegetated area. Less than 10% undesirable vegetation occurs in the required native vegetated surface area. Vegetated Area Soil compaction Soil in the native vegetation area compacted. Less than 8% of native vegetation area is compacted. Insufficient vegetation Less than 3.5 square feet of native vegetation area for every 1 square foot of impervious surface. A minimum of 3.5 square feet of native vegetation area for every 1 square foot of impervious surface. Excess slope Slope of native vegetation area greater than 15%. Slope of native growth area does not exceed 15%. NO. 29 – PERFORATED PIPE CONNECTIONS BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Blocking, obstructions Debris or trash limiting flow into perforated pipe system or outfall of BMP is plugged or otherwise nonfunctioning. Outfall of BMP is receiving designed flows from perforated pipe connection. Inflow Inflow impeded Inflow into the perforated pipe is partially or fully blocked or altered to prevent flow from getting into the pipe. Inflow to the perforated pipe is unimpeded. Pipe Trench Area Surface compacted Ground surface over the perforated pipe trench is compacted or covered with impermeable material. Ground surface over the perforated pipe is not compacted and free of any impervious cover. Outflow Outflow impeded Outflow from the perforated pipe into the public drainage system is blocked. Outflow to the public drainage system is unimpeded. Outfall Area Erosion or landslides Existence of the perforated pipe is causing or exasperating erosion or landslides. Perforated pipe system is sealed off and an alternative BMP is implemented. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-43 NO. 32 – RAINWATER HARVESTING BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Insufficient storage volume No rain water in storage unit at the beginning of the rain season. Maximum storage available at the beginning of the rain season (Oct. 1). Collection Area Trash and debris Trash of debris on collection area may plug filter system Collection area clear of trash and debris. Filter Restricted or plugged filter Filter is partially or fully plugged preventing water from getting in to the storage unit. Filter is allowing collection water into storage unit. NO. 33 – ROCK PAD BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on rock pad site. Rock pad site free of any trash or debris. Rock Pad Area Insufficient rock pad size Rock pad is not 2 feet by 3 feet by 6 inches thick or as designed. Rock pad is 2 feet by 3 feet by 6 inches thick or as designed. Vegetation growth Vegetation is seen growing in or through rock pad. No vegetation within rock pad area. Rock Exposed soil Soil can be seen through the rock pad. Full thickness of the rock pad is in place, no soil visible through rock pad. NO. 34 – SHEET FLOW BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on the sheet flow site. Sheet flow site free of any trash or debris. Sheet flow area Erosion Soil erosion occurring in sheet flow zone. Soil erosion is not occurring and rills and channels have been repaired. Concentrated flow Sheet flow is not occurring in the sheet flow zone. Sheet flow area is regraded to provide sheet flow. NO. 35 – SPLASH BLOCK BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on the splash block. Splash block site free of any trash or debris. Splash Block Dislodged splash block Splash block moved from outlet of downspout. Splash block correctly positioned to catch discharge from downspout. Channeling Water coming off the splash block causing erosion. No erosion occurs from the splash block. Downspout water misdirected Water coming from the downspout is not discharging to the dispersal area. Water is discharging normally to the dispersal area. Technical Information Report Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendix B Construction Stormwater Pollution Prevention Plan Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors Construction Stormwater Pollution Prevention Plan PREPARED FOR: Northwest Gourmet Food Products, Inc. 600 SW 7th Street Renton, WA 98057-2916 Contact: Mike Gilroy PROJECT: Northwest Gourmet Freezer Addition 600 SW 7th Street Renton, WA 98057-2916 AHBL No. 2160966.10 PREPARED BY: Tyler D. Watkins, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager J. Matthew Weber, PE Principal DATE: June 2018 Revised August 2018 Construction Stormwater Pollution Prevention Plan PREPARED FOR: Northwest Gourmet Food Products, Inc. 600 SW 7th Street Renton, WA 98057-2916 Contact: Mike Gilroy PROJECT: Northwest Gourmet Freezer Addition 600 SW 7th Street Renton, WA 98057-2916 AHBL No. 2160966.10 PREPARED BY: Tyler D. Watkins, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager J. Matthew Weber, PE Principal DATE: June 2018 Revised August 2018 I hereby state that this Construction Stormwater Pollution Prevention Plan for the Northwest Gourmet Freezer Addition project has been prepared by me or under my supervision, and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that the City of Renton does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. 08/31/2018 Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Table of Contents Section Page 1.0 Purpose ........................................................................................................................................... 1 2.0 Conditions of Use .......................................................................................................................... 2 3.0 Existing Site Conditions ................................................................................................................ 2 3.1 Existing Cover ..................................................................................................................... 2 3.2 Topography and Design ...................................................................................................... 2 3.3 Adjacent Areas .................................................................................................................... 2 4.0 ESC Plan Analysis and Design (Part A) ....................................................................................... 2 4.1 ESC Measures .................................................................................................................... 2 4.1.1 Clearing Limits ....................................................................................................... 2 4.1.2 Cover Measures ..................................................................................................... 3 4.1.3 Perimeter Protection .............................................................................................. 4 4.1.4 Traffic Area Stabilization ........................................................................................ 4 4.1.5 Sediment Retention ............................................................................................... 4 4.1.6 Surface Water Collection ....................................................................................... 4 4.1.7 Dewatering Control ................................................................................................ 4 4.1.8 Dust Control ........................................................................................................... 4 4.1.9 Flow Control ........................................................................................................... 4 4.1.10 Control Pollutants ................................................................................................... 5 4.1.11 Protect Existing and Proposed Flow Control BMPs ............................................... 5 4.1.12 Maintain BMPs ....................................................................................................... 5 4.1.13 Manage the Project ................................................................................................ 5 4.2 Erosion Problem Areas ....................................................................................................... 5 5.0 Stormwater Pollution Prevention and Spill (SWPPS) Plan Design (Part B) ............................. 5 5.1 Pollution and Spill Prevention Source Controls and BMPs ................................................. 6 5.2 Responsible Personnel and Contact Information ............................................................... 7 5.3 Pollution and Spill Prevention Worksheets ......................................................................... 7 5.4 Disposal Methods ................................................................................................................ 8 6.0 ESC Performance and Compliance Provisions .......................................................................... 8 6.1 ESC Supervisor ................................................................................................................... 8 6.2 Monitoring of Discharges .................................................................................................... 8 Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition AHBL No. 2160966.10 6.3 ESC Performance ............................................................................................................... 8 6.4 Flexible Compliance ............................................................................................................ 9 6.5 Roads and Utilities Compliance .......................................................................................... 9 6.6 Alternative and Experimental Measures ............................................................................. 9 7.0 ESC Implementation Requirements ............................................................................................. 9 7.1 Wet Season Requirements ................................................................................................. 9 7.2 Critical Areas Restriction ................................................................................................... 10 7.3 Maintenance Requirement ................................................................................................ 10 7.4 Construction Sequence ..................................................................................................... 10 7.5 Final Stabilization .............................................................................................................. 11 7.6 NPDES Requirements ...................................................................................................... 12 7.7 Forest Practice Permit Requirements ............................................................................... 12 8.0 Construction Schedule ................................................................................................................ 12 Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendices Appendix A Exhibits A-1 ............. Vicinity Map A-2 ............. Existing Utility Map A-3 ............. Critical Area Map A-4 ............. Permit Set Appendix B Recommended BMPs Appendix C Inspection and Maintenance Report Forms Appendix D Geotechnical Report By E3RA, Inc., May 22, 2013 Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 1 AHBL No. 2160966.10 1.0 Purpose In 1972, Congress passed the Federal Water Pollution Control Act (FWPCA), also known as the Clean Water Act (CWA), to restore and maintain the quality of the nation's waterways. The ultimate goal was to ensure that rivers and streams were fishable, swimmable, and drinkable. In 1987, the Water Quality Act (WQA) added provisions to the CWA that allowed the Environmental Protection Agency (EPA) to govern stormwater discharges from construction sites. In 1998, the EPA published the final notice for General Permits for Storm Water Discharges from Construction Activities Disturbing 5 Acres or Greater (63 Federal Register 7898, February 14, 1998). The general permit includes provisions for development of a Stormwater Pollution Prevention Plan (SWPPP) to maximize the potential benefits of pollution prevention, and sediment and erosion control measures at construction sites. Development, implementation, and maintenance of the Construction SWPPP will provide the selected General Contractor with the framework for reducing soil erosion and minimizing pollutants in stormwater during construction. The Construction SWPPP will:  Define the characteristics of the site and the type of construction that will occur.  Describe the practices that will be implemented to control erosion, and the release of pollutants in stormwater.  Create an implementation schedule to ensure that the practices described in this Construction SWPPP are in fact implemented; and to evaluate the plan's effectiveness in reducing erosion, sediment, and pollutant levels in stormwater discharged from the site.  Describe the final stabilization/termination design to minimize erosion and prevent stormwater impacts after construction is complete. This Construction SWPPP includes the following:  Identification of the Construction SWPPP Coordinator with a description of duties.  Identification of the Stormwater Pollution Prevention Team (SWPP Team) that will assist in implementation of the Construction SWPPP during construction.  Description of the existing site conditions, including existing land use for the s ite, soil types at the site, as well as the location of surface waters that are located on or next to the site.  Identification of the body or bodies of water that will receive runoff from the construction site, including the ultimate body of water that receives the stormwater.  Identification of drainage areas and potential stormwater contaminants.  Description of stormwater management controls and various Best Management Practices (BMPs) necessary to reduce erosion, sediment, and pollutants in stormwater dis charge.  Description of the facility monitoring plan, and how controls will be coordinated with construction activities.  Description of the implementation schedule and provisions for amendment of the plan. Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 2 AHBL No. 2160966.10 2.0 Conditions of Use This report accompanies the civil engineering plans and documents for the Northwest Gourmet Freezer Addition project located at 600 SW 7th Street in the City of Renton. The site is located on Parcel No. 1823059254. The project proposes a 6,386-square-foot freezer addition placed over the existing loading dock area against the existing 66,786-square-foot building. The project site is approximately 5.01 acres. Stormwater management is to comply with the 2016 King County Surface Water Design Manual (KCSWDM), as amended by the City of Renton, the 2016 City of Renton Surface Water Design Manual (CRSWDM). 3.0 Existing Site Conditions 3.1 Existing Cover The 5.01-acre site is currently occupied by Northwest Gourmet Food Products, Inc . The site contains two existing buildings, a 66,786-square-foot food processing plant/office building and a 1,680-square-foot storage shed. The main food processing building has loading docks along the east side, along with a paved area used for truck maneuvering. The site includes a parking lot to the south and west of the main building, a drive aisle along the north side, and a landscape/lawn area to the southeast. The northernmost portion of the site near the BNSF railroad consists of dense trees. 3.2 Topography and Design The site is relatively flat. Runoff from the site is collected by the existing private onsite storm drainage system and discharged into the public storm drainage system within SW 7th Street. A regional facility is utilized for treatment and flow control. The proposed project plans to remove a portion of the existing paved loading dock area on the east side of the building and construct a 6,386-square-foot freezer addition. The proposed building addition will be located entirely over an area that was previously impervious. Stormwater runoff from the building addition roof will discharge onto splash blocks and will be collected by the existing private storm drainage system. 3.3 Adjacent Areas The site is bordered by a railroad owned by BNSF Railway Co. to the north, Harper Engineering to the west, SW 7th Street to the south, and Puget Sound Electrical JATC to the east beyond a right-of-way owned by BNSF Railway Co. 4.0 ESC Plan Analysis and Design (Part A) 4.1 ESC Measures The purpose of this section is to describe how each of the 13 erosion and sediment control (ESC) measures has been addressed and to identify the type and location of BMPs used to satisfy the required measure. 4.1.1 Clearing Limits Clearing limits are identified on the plans. Prior to beginning land disturbing activities, clearing limits will be marked with flagging (BMP D.2.1.1) or high visibility plastic or metal fence (BMP D.2.1.1.1). Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 3 AHBL No. 2160966.10 4.1.2 Cover Measures Because source control is the most important form of erosion control, construction practices must adhere to strict cover requirements. Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project include:  Mulching (BMP D.2.1.2.2)  Temporary and Permanent Seeding (BMP D.2.1.2.6) More specifically, during the period of May 1 through September 30, the Contractor will not be allowed to leave soils unprotected for more than 7 days; and immediate seeding will be required for areas brought to finish grade with no further work planned for the next 30 days. Areas to be paved may be armored with crushed rock subbase in place of other stabilizing measures. The area of clearing will be limited to the amount that can be stabilized by September 30, of that year. During the period of October 1 through April 30, all disturbed soil areas will be covered or stabilized within 2 days or 24 hours when a major storm even is predicted. Cover measures may include mulching, netting, plastic sheeting, erosion control blankets, or f ree draining material. The extent of clearing shall be limited to the amount of land that can be covered or stabilized within 24 hours. Soil stockpiles shall be stabilized by plastic covering or surrounded by filter fabric fence. The Contractor has the option of providing all required material for cover measures onsite at all times or preparing a plan of action to submit to the City of Renton. A plan of action shall contain the following:  Contractor’s name, address, phone number, and emergency phone number.  Alternate contact with above information.  Clearly defined plan of action designed to prevent offsite migration of sediments, which will be implemented in the event that a major storm is predicted or offsite erosion is observed by the Contractor, his/her employees, or the City.  Description of materials to be used for cover and means by which it will be placed. List equipment to be used or number of personnel anticipated to be used to spread material.  Vendor or supplier of materials used; list two alternates and include phone numbers.  Means and timeframe for cleanup of any materials that escape offsite and for repairs to the natural system if damages have occurred. In order for the ESC facilities to function properly, they must be maintained and sediment removed on a regular basis. Inspection and sediment removal shall be performed on all ESC facilities, as described in the inspection schedule located in Section 7.3 of this report. Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 4 AHBL No. 2160966.10 4.1.3 Perimeter Protection Perimeter protection to filter sediment from sheet wash shall be located downslope of all disturbed areas and shall be installed prior to upslope grading. Filter fabric fencing (BMP D.2.1.3.1) will be required along the south side of the building addition and around stockpile areas to prevent sediment-laden stormwater from being transported offsite. During the wet season, 50 linear feet of filter fabric fencing per acre is required to be stockpiled onsite. 4.1.4 Traffic Area Stabilization The existing paved east driveway will be used as a stabilized const ruction entrance. The construction entrance will be used to prevent the transport of sediment onto the adjacent paved surfaces. If sediment is transported onto the road surface, the road shall be cleaned each day by sweeping or vacuuming prior to washing. Sediment removal by washing alone will not be allowed. If sediment is tracked from the site, the City may require stabilization of internal roads and car parking areas to contain the sediment (BMP D.2.1.4.2) or require the installation of a wheel wash basin (BMP D.2.1.4.3). 4.1.5 Sediment Retention The first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm drain inlet protection (BMP D.3.5.3) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site, including offsite catch basins located downstream of the project site. Storm drain inlet sediment protection will prevent coarse sediment from entering the drainage system prior to permanent stabilization of the disturbed areas. 4.1.6 Surface Water Collection The project will not require interceptor swales or dikes (BMP D.2.1.6.1) since there are no steep slopes within the site. During construction, surface water will sheet flow onto the existing truck dock pavement to the north. Once the site is stabilized, surface water from the building addition roof will be collected by roof downspouts. Outlet protection (BMP D.2.1.6.5) is not required at the roof drain outlets since they will discharge onto existing pavement. 4.1.7 Dewatering Control Dewatering during construction is not anticipated. 4.1.8 Dust Control Dust control shall be implemented when exposed soils are dry to the point that wind transport is possible and roadways, drainage ways, or surface waters are likely to be impacted. Water shall be used on exposed soils by spraying until wet, but runoff shall not be generated by spraying. Exposed areas shall be resprayed as needed. Oil shall not be used for dust control. 4.1.9 Flow Control Stormwater flows during construction are expected to be minimal. Since the project is simply replacing impervious surfaces, the overall impervious area will remain the same in the developed conditions. Additionally, the 2-year and 10-year runoff peaks will remain unchanged. Therefore, flow control will not be required during construction. Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 5 AHBL No. 2160966.10 4.1.10 Control Pollutants Stormwater Pollution Prevention and Spill (SWPPS) measures are required to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses for construction-related activities. Section 5.0 identifies these SWPPS measures. 4.1.11 Protect Existing and Proposed Flow Control BMPs Protection measures shall be applied/installed and maintained to prevent adverse impacts to areas of proposed flow control BMPs within the project site. There are no known existing flow control BMPs located on the project site. The Contractor is responsible for protecting flow control BMPs. 4.1.12 Maintain BMPs Protection measures, per BMP D.2.1.11, shall be maintained to assure continued performance of their intended function and protect other disturbed areas of the project. There are no known existing flow control BMPs located on the project site. The Contractor is responsible for maintaining all temporary and permanent BMPs. 4.1.13 Manage the Project Coordination and timing of site development activities relative to ESC concerns (Section D.2.4 of the CRSWDM) and timely inspection, maintenance, and update of protective measures (Section D.2.3 of the CRSWDM) are necessary to effectively manage the project and assure the success of protective ESC and SWPPS design and implementation. The Contractor is responsible for managing the project. 4.2 Erosion Problem Areas The erosion potential of the site soils is moderate to low, as there are no known historic erosion problems within or around the project site. Refer to Appendix B for the Recommended BMPs. 5.0 Stormwater Pollution Prevention and Spill (SWPPS) Plan Des ign (Part B) The Stormwater Pollution Prevention and Spill (SWPPS) Plan includes three elements : A site plan (attached as Appendix A-4), a pollution prevention report (this document), and a spill prevention and cleanup report. The spill prevention and cleanup report includes identifying the expected sources of potential pollution and spills that may occur during construction, and works to develop a plan to prevent pollution and spills. It also develops a plan to mitigate spills that may occur. The SWPPS Plan will be kept onsite at all times during construction. The General Contractor will be responsible to ensure that subcontractors are aware of the SWPPS Plan, and a form or record will be provided stating that all subcontractors have read and agree to the SWPPS Plan. An employee training worksheet is provided for the Contractor’s use (see Appendix C). A SWPPS Site Plan has been submitted with the civil engineering plans and can be found in Appendix A-4 (Permit Set) (to be updated with input from the Contractor). The SWPPS Site Plan, Pollution Prevention Report, and Spill Prevention and Cleanup Report have been developed; and BMPs have been selected based on Section 2.3.1.4 of the CRSWDM and the King County Stormwater Pollution Prevention Manual (KCSPPM). (The below plan will be updated with input from the Contractor.) Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 6 AHBL No. 2160966.10 5.1 Pollution and Spill Prevention Source Controls and BMPs The sources of pollution and spills will be identified by the Contractor in the spaces provided below, and the BMPs to be used for each source for prevention of both pollution and spills will be provided by the Contractor in the spaces provided below: Liquids that will be handled or stored onsite are the following: __________. Containers will be stored as shown on Sheet __________ and include the following types and sizes: ___________. Tight-fitting lids shall be placed on all containers containing liquids. Containers shall be covered with plastic sheeting during rain events. Drip pans or absorbent materials shall be placed beneath all mounted container taps and at all potential drip and spill locations during filling and unloading of containers. Containers shall be stored such that if a container leaks or spills, the contents will not be discharged, flow, or be washed into the storm drainage system, surface water, or groundwater. Appropriate spill cleanup materials shall be stored and maintained near the container storage area. Storage area shall be swept and cleaned as needed. Area shall not be hosed down such that water drains to the storm drainage system or neighboring areas. Containers shall be checked daily for leaks and spills and replaced as necessary. All spilled liquids will be collected and disposed of properly. Spill control devices shall be routinely inspected on a weekly basis. Dry pesticides and fertilizers shall be covered with plastic sheeting or stored in a sealed container. Materials shall be stored on pallets or another raised method to prevent contact with stormwater runoff. Alternatively, the materials sh all be contained in a manner such that if the container leaks or spills, the contents will not discharge, flow, or be washed into the storm drainage system, surface waters, or groundwater. Maintenance requirements are the same as liquid materials described above. Chemicals that will be handled or stored onsite are the following: __________. Containers will be stored as shown on Sheet __________ and include the following types and sizes: __________. BMPs and Maintenance requirements are the same as liquids with the addition of the following __________. Soil, sand, and other erodible materials shall be stored onsite as shown on Sheet __________. Materials shall be covered with plastic sheeting as described in Appendix B. Perimeter controls shall be constructed as shown on the TESC plan to prevent eroded materials from leaving the project site. Fueling shall not occur onsite. If fueling does occur onsite, the Contractor shall develop a containment plan for spills and provide lighting and signage if fueling occurs at night in conformance with the KCSPPM. Maintenance and repair of vehicles shall not occur onsite. If maintenance or repair of vehicles does occur onsite, the Contractor shall develop a spill prevention plan in Conformance with the KCSPPM. Truck wheel washing shall occur at the wheel wash station as shown on Sheet __________. All other vehicle washing shall occur in a controlled manner, such that runoff is collected and disposed of in a legal manner. Washing areas must be lined with an impervious membrane to prevent contamination of groundwater. Rinsing of hand tools shall occur within a designated washing area. Water for washing shall be collected and disposed of in a legal manner. Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 7 AHBL No. 2160966.10 Contaminated soils are not expected to be found onsite. If located, they shall be covered with plastic sheeting or contained to prevent stormwater from carrying pollutants away to surface or ground waters. Appropriate spill cleanup materials, such as brooms, dustpans, vacuum sweepers, etc., shall be stored and maintained near the storage area. Storage area shall be swept and cleaned as needed. Area shall not be hosed down such that water drains to the storm drainage system, groundwater, surface water, or neighboring areas. During concrete and asphalt construction, the Contractor shall provide the following BMPs or equivalent measures, methods or practices as required: 1. Drip pans, ground cloths, heavy cardboard or plywood wherever concrete, asphalt and asphalt emulsion chunks and drips are likely to fall unintentionally, such as beneath extraction points from mixing equipment. 2. Storm drain inlet protection is being provided as shown on Sheet C1.0. Storm drains shall be covered to prevent concrete and asphalt from entering the storm system. 3. Concrete, concrete slurry, and rinse water shall be contained and collected, and shall not be washed or allowed to discharge into storm drain, ditch, or neighboring parcels. All collected runoff shall be properly disposed of. 4. Contractor shall designate an area where application and mixing equipment cleaning will be conducted. Rinse water and slurry shall be collected, contained, and disposed of in a legal manner. 5. Routine maintenance: The pouring area shall be swept at the end of each day or more frequently if needed. Loose aggregate chunks and dust shall be collected. Areas shall not be hosed down. The Contractor may provide the following optional BMPs if the above do not provide adequate source controls: 6. Cover portable mixing equipment with an awning or plastic sheeting to prevent contact with rainfall. 7. Provide catch basin inserts configured for pollutant removal. Water with elevated pH levels shall not be discharged from the site. Contractor shall monitor stormwater for pH prior to discharging from the site. Contractor shall implement a pH treatment plan if pH is not within the natural range 5.2 Responsible Personnel and Contact Information [name] with [company] shall be responsible for pollution and spill prevention and cleanup and can be contacted at [phone] or [email] . Contractor shall fill out the attached Pollution Prevention Team Worksheet (see Appendix C). 5.3 Pollution and Spill Prevention Worksheets Pollution prevention, BMP implementation reports, material inventory worksheets, pollutant source identification worksheet, and spill/leak report may be found attached as Appendix C. Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 8 AHBL No. 2160966.10 5.4 Disposal Methods Contractor shall dispose of asphalt, concrete, and wastewater in a legal manner. Options include disposal at a local landfill or at a recycling center, as allowed. 6.0 ESC Performance and Compliance Provisions 6.1 ESC Supervisor The Contractor shall appoint a Certified Erosion and Sediment Control Lead (CESCL) or Certified Professional in Erosion and Sediment Control (CPESC) (BMP D.4.1) for the project, and the appointee must be approved by the City. The duties of the CESCL or CPESC include:  Maintaining files onsite at all times, which include the Construction SWPPP and any associated permits and plans.  Directing BMP installation, inspection, maintenance, m odification, and removal.  Keeping a log of all turbidity measurements taken onsite and making it available to the City of Renton Community & Economic Development upon request.  Updating all project drawings and the Construction SWPPP with changes made.  Keeping daily logs and inspection reports.  Facilitating, participating in, and taking corrective actions resulting from inspections performed by outside agencies or the owner. To aid in the implementation of the Construction SWPPP, the members of the SWPP Team include the following: the Contractor, the CESCL or CPESC, the City of Renton Inspector, and AHBL. The General Contractor will ensure all housekeeping and monitoring procedures are implemented, while the CESCL or CPESC will ensure the integrity of the structural BMPs. The City of Renton Inspector and AHBL will observe construction and erosion control practices and recommend revisions or additions to the Construction SWPPP and drawings. 6.2 Monitoring of Discharges The ESC supervisor shall have a turbidity m eter onsite and shall use it to monitor surface and stormwater discharges from the project site whenever runoff occurs from onsite activities. A log of all turbidity measurements taken onsite shall be kept and made available to the City of Renton upon request. 6.3 ESC Performance ECS measures shall be installed and maintained to prevent, to the maximum extent practicable, the transport of sediment from the project site to downstream drainage systems. Stormwater turbidity shall be monitored based on Section D.4.3 of the CRSWDM. Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 9 AHBL No. 2160966.10 6.4 Flexible Compliance Any deviation to the Construction SWPPP will be documented and reported to the City for approval. 6.5 Roads and Utilities Compliance No alternative BMPs are used in road and utility compliance. 6.6 Alternative and Experimental Measures No alternative or experimental measures are to be used at this time. 7.0 ESC Implementation Requirements 7.1 Wet Season Requirements All of the following provisions for wet season construction are detailed in referenced sections: 1. The allowed time that a disturbed area may remain unworked without cover measures is reduced to two consecutive working days, rather than seven (D.3.2). 2. Stockpiles and steep cut and fill slopes are to be protected if unworked for more than 12 hours (D.3.2). 3. Cover materials sufficient to cover all disturbed areas shall be stockpiled onsite (D.3.2). 4. All areas that are to be unworked during the wet season shall be seeded within one week of the beginning of the wet season (D.3.2.5). 5. Mulch is required to protect all seeded areas (D.3.2.1). 6. Fifty linear feet of filter fabric fence (and the necessary stakes) per acre of disturbance must be stockpiled onsite (D.3.3.1). 7. Construction road and parking lot stabilization are required for all sites, unless the site is underlain by coarse-grained soil (D.3.4.2). 8. Sediment retention is required unless no offsite discharge is anticipated for the specified design flow (D.3.5). 9. Surface water controls are required, unless no offsite discharge is anticipated for the specified design flow (D.3.6). 10. Phasing and more conservative BMPs must be evaluated for construction activity near surface waters (D.5.3). 11. Any runoff generated by dewatering may be required to discharge to the sanitary sewer (with appropriate discharge authorization), portable sand filter sys tems, or holding tanks (D.2.1.7) 12. The frequency of maintenance review increases from monthly to weekly (D.5.4). Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 10 AHBL No. 2160966.10 7.2 Critical Areas Restriction An area approximately 600 feet to the west of the site is labeled as a “Special Flood Hazard Area - 100-year flood” per the City of Renton GIS Maps. However, the site is not located within the flood hazard area. The majority of the site is labelled as a “Seismic Hazard Area,” with the exception of the northeast corner of the site. The northern edge of the site adjacent to the railroad is marked as a steep slope, with slopes ranging from 15 to 25 percent. A small portion of this area has slopes ranging from 25 to 40 percent. The entire sloped portion is located within the existing dense trees along the north edge of the site. Refer to the Critical Area Map attached as Appendix A-3. 7.3 Maintenance Requirement All ESC measures shall be maintained and reviewed on a regular basis, as prescribed in the maintenance requirements for each BMP (see Appendix B). The ESC supervisor shall review the site at least twice a month during the dry season, weekly during the wet season, and within 24 hours of significant storms. The City may require that a written record of these reviews be kept onsite, with copies submitted to City of Renton Community & Economic Development within 48 hours. Documentation If the Department of Development and Environmental Services (DDES) requires that a written record be maintained, a standard ESC Maintenance Report (D-95) may be used. A copy of all required maintenance reports shall be kept onsite throughout the duration of construction. The maintenance inspection report will be made after each inspection. Copies of the report forms to be completed by the Construction SWPPP Coordinator are included in Appendix C of this Construction SWPPP. Completed forms will be provided to the City Inspector and will also be maintained onsite during the entire construction project. If construction activities or design modifications are made to the site plan that could impact stormwater or if the Engineer of Record determines that the measures are not adequate to prevent erosion and the discharge of sediment from the site (based on turbidity measurements), this Construction SWPPP will be amended appropriately. The amended Construction SWPPP will have a description of the new activities that contribute to the increased pollutant loading and the planned source control activities. Review Timing During the wet season, weekly reviews shall be carried out every 6 to 9 calendar days. During the dry season, monthly reviews shall be carried out within 3 days of the calendar day for the last inspection. Reviews shall also take place within 24 hours of significant storms. In general, a significant storm is one with more than 0.5 inch of rain in 24 hours or less. In order for the ESC facilities to function properly, they must be maintained and sediment removed on a regular basis. Inspection and sediment removal shall be performed on all ESC facilities, as described in the Inspection and Maintenance Report Forms included in Appendix C . 7.4 Construction Sequence 1. Hold the pre-construction meeting with the City of Renton. Identify required inspections. 2. Post sign with name and phone number of ESC Supervisor (may be consolidated with the required notice of construction sign). Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 11 AHBL No. 2160966.10 3. Flag or fence clearing and construction limits. 4. Install inlet sediment protection as shown on plans. 5. Utilize the existing east driveway for stabilized construction access. Sweep entrance daily. 6. Install filter fabric fence as shown on plans. 7. Sawcut and remove existing asphalt pavement as shown on plans. 8. Construct building addition and concrete pad for compressor per architectural plans. 9. Maintain erosion control measures in accordance with City of Renton standards and manufacturer’s recommendations. 10. Relocate erosion control measures or install new measures so that, as site conditions change, the erosion and sediment control is always in accordance with the City of Renton erosion and sediment control standards. 11. Cover all areas that will be unworked for more than 7 days during the dry season or 2 days during the wet season with straw, wood fiber mulch, compost, plastic sheeting, or equivalent. 12. Stabilize all areas within 7 days of reaching final grade. 13. Seed, sod, stabilize, or cover any areas to remain unworked for more than 30 days. 14. Upon completion of the project, stabilize all disturbed areas and remove BMPs , if appropriate, upon approval of the owner, engineer, and City of Renton inspector. 7.5 Final Stabilization Prior to obtaining final construction approval, the site shall be stabilized, the structural ESC measures removed, and drainage facilities cleaned. To obtain final construction approval, the following conditions must be met: 1. All disturbed areas of the site shall be vegetated or otherwise permanently stabilized. At a minimum, disturbed areas shall be seeded and mulched with a high likelihood that sufficient cover will develop shortly after final approval. Mulch without seeding is not adequate to allow final approval. 2. Structural measures such as, but not limited to, filter fabric fences, pipe slope drains, construction entrances, and storm drain inlet protection shall be removed from the site. Measures that will quickly decompose such as brush barriers and organic mulches may be left in place. The City of Renton inspector must approve an applicant’s proposal to remove fencing prior to the establishment of vegetation. 3. All permanent surface water facilities, including catch basins, manhol es, pipes, ditches, channels, flow control facilities, and water quality facilities, shall be cleaned. Any offsite catch basin that required protection during construction shall also be cleaned . Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition 12 AHBL No. 2160966.10 7.6 NPDES Requirements The CRSWDM is equivalent to the EPA required National Pollutant Discharge Elimination System (NPDES) permit through the Stormwater Management Manual for Western Washington (Department of Ecology, 2012). The Department of Ecology stormwater permit application requires the filling of a Notice of Intent (NOI) at least 30 days prior to the start of construction. 7.7 Forest Practice Permit Requirements The project does not clear more than 5,000 board feet of timber and does not require a Class IV Special Forest Practice permit from the Washington State Department of Natural Resources. 8.0 Construction Schedule Construction is scheduled to begin in summer 2018 and be completed by fall 2018. This analysis is based on data and records either supplied to or obtained by AHBL . These documents are referenced within the text of the analysis. The analysis has been prepared using procedures and practices within the standard accepted practices of the industry. We conclude that this project, as proposed, will not create any new problems within the existing downstream dr ainage system. This project will not noticeably aggravate any existing downstream problems due to either water quality or quantity. AHBL, Inc. Tyler D. Watkins, EIT Project Engineer TDW /lsk/EL June 2018 Revised August 2018 Q:\2016\2160966\WORDPROC\Reports\20180831 Rpt (CSWPPP) 2160966.10.docx Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendix A Exhibits A-1 .................... Vicinity Map A-2 .................... Existing Utility Map A-3 .................... Critical Area Map A-4 .................... Permit Set 2215 N. 30th Street, #300 Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX www.ahbl.com NW Gourmet Freezer Addition Project #2160966.10 Vicinity Map App A-1 1,200200 Existing Utility Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes 06/05/2018 Legend 136 0 68 136 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Addresses Parcels 2' Primary 2' Intermediate Renton Fire Hydrant Water Main Lateral Line Domestic Fire Hydrant Irrigation Clean Outs Manholes Service Connections Lateral Lines Gravity Mains Renton Private Network Structures Inlet Manhole Utility Vault Unknown Structure Stormwater Main Facility Outline Private Network Structures Inlet Manhole Utility Vault Unknown Structure Private Detention Facilities Pond Tank Vault Wetland Private Pipe Private Facility Outline Flow Control BMP Conduit Duct Bank Trench Appendix A-2 - Site 2,400400 Critical Area Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes 06/05/2018 Legend 272 0 136 272 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Addresses Parcels Floodway Special Flood Hazard Areas (100 year flood) Landslide VERY HIGH HIGH MODERATE UNCLASSIFED Slope City of Renton >15% & <=25% >25% & <=40% (Sensitive) >40% & <=90% (Protected) >90% (Protected) Environment Designations Natural Shoreline High Intensity Shoreline Isolated High Intensity Shoreline Residential Urban Conservancy Jurisdictions Wetlands Seismic Hazard Areas Faults 2' Primary 2' Intermediate Appendix A-3 - Site EXISTING BUILDING 66,786 SF SL EXISTING BUILDING 1,680 SF FF CL CONSTRUCTION ENTRANCE REMOVE ASPHALT PAVEMENT PROTECT EXISTING LAWN IPREMOVE CONCRETE PAVEMENT IP EXISTING CATCH BASIN COORDINATE PAVEMENT REMOVAL LIMITS WITH FOUNDATION PLAN. REMOVE PAVEMENT AS NECESSARY.Sheet No.Designed by:Drawn by:Checked by:Sheet Title:Revisions:Issue Set & Date:Client:Job No.of Sheets123Project Title:535 DOCK ST, SUITE 211, TACOMA, WA 98402TEL: 253.284.9680 FAX:253.284.9681WWW.TAHOMADESIGNGROUP.COMTAHOMADESIGN GROUPNorthwest Gourmet Foods - Freezer Addition 600 SW 7th St, Renton, WA 98057 Northwest Gourmet FoodsFreezer AdditionNorthwest Gourmet Foods600 SW 7th St, Renton, WA 98057Mike Gilroy (425) 793-5001Issue For ClientReview9/4/20182160966.10TESC ANDDEMOLITION PLANTDWTDWSTKC1.02215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB TACOMA SEATTLE SPOKANE TRI-CITIES CONSTRUCTION SEQUENCE 1.HOLD THE PRE-CONSTRUCTION MEETING WITH THE CITY OF RENTON. IDENTIFY REQUIRED INSPECTIONS. 2.POST SIGN WITH NAME AND PHONE NUMBER OF ESC SUPERVISOR (MAY BE CONSOLIDATED WITH THE REQUIRED NOTICE OF CONSTRUCTION SIGN). 3.FLAG OR FENCE CLEARING AND CONSTRUCTION LIMITS. 4.INSTALL INLET SEDIMENT PROTECTION AS SHOWN ON PLANS. 5.UTILIZE THE EXISTING EAST DRIVEWAY FOR STABILIZED CONSTRUCTION ACCESS. SWEEP ENTRANCE DAILY. 6.INSTALL FILTER FABRIC FENCE AS SHOWN ON PLANS. 7.SAWCUT AND REMOVE EXISTING ASPHALT PAVEMENT AS SHOWN ON PLANS. 8.CONSTRUCT BUILDING ADDITION AND CONCRETE PAD FOR COMPRESSOR PER ARCHITECTURAL PLANS. 9.MAINTAIN EROSION CONTROL MEASURES IN ACCORDANCE WITH CITY OF RENTON STANDARDS AND MANUFACTURER'S RECOMMENDATIONS. 10.RELOCATE EROSION CONTROL MEASURES OR INSTALL NEW MEASURES SO THAT, AS SITE CONDITIONS CHANGE, THE EROSION AND SEDIMENT CONTROL IS ALWAYS IN ACCORDANCE WITH THE CITY OF RENTON EROSION AND SEDIMENT CONTROL STANDARDS. 11.COVER ALL AREAS THAT WILL BE UNWORKED FOR MORE THAN SEVEN DAYS DURING THE DRY SEASON OR TWO DAYS DURING THE WET SEASON WITH STRAW, WOOD FIBER MULCH, COMPOST, PLASTIC SHEETING, OR EQUIVALENT. 12.STABILIZE ALL AREAS WITHIN SEVEN DAYS OF REACHING FINAL GRADE. 13.SEED, SOD, STABILIZE, OR COVER ANY AREAS TO REMAIN UNWORKED FOR MORE THAN 30 DAYS. 14.UPON COMPLETION OF THE PROJECT, STABILIZE ALL DISTURBED AREAS AND REMOVE BMPS, IF APPROPRIATE, UPON APPROVAL OF THE OWNER, ENGINEER, AND CITY OF RENTON INSPECTOR. 1.PROVIDE TEMPORARY EROSION CONTROL MEASURES AS SHOWN ON PLANS. CONTRACTOR IS RESPONSIBLE FOR MAINTAINING AND ADJUSTING EROSION CONTROL FACILITIES AS SITE CONDITIONS CHANGE. REFER TO THE T.E.S.C. NOTES AND DETAILS ON SHEET C1.1. 2.CONTRACTOR SHALL DESIGNATE A WASHINGTON STATE CERTIFIED EROSION AND SEDIMENT CONTROL LEAD (CESCL) WHO WILL BE ON-SITE OR ON CALL AT ALL TIMES. THE EROSION CONTROL LEAD SHALL HAVE THE AUTHORITY TO IMPLEMENT THE STORMWATER POLLUTION PREVENTION PLAN BASED ON SITE CONDITIONS WITHIN THEIR SCOPE. IF THE METHODS INDICATED FOR EROSION AND SEDIMENT CONTROL ARE NOT ADEQUATE, THE CESCL SHALL IMPLEMENT ADDITIONAL METHODS AS REQUIRED. 3.CONTRACTOR SHALL IMPLEMENT AND CHANGE EROSION CONTROL MEASURES AS NECESSITATED BY CONSTRUCTION ACTIVITIES. 4.CONTRACTOR SHALL MAINTAIN BMP C150: MATERIALS ON HAND, ON-SITE IN AN AREA EASILY ACCESSIBLE. 5.CONTRACTOR TO FOLLOW BMP C153: MATERIAL DELIVERY, STORAGE AND CONTAINMENT IN THE STORAGE OF HAZARDOUS MATERIALS ONSITE. TESC NOTES 1.DEMOLITION: IT IS THE INTENT UNDER THE WORK OF THIS CONTRACT TO INCLUDE, BUT NOT LIMITED TO, THE DEMOLITION OF ALL EXISTING PAVING, AND OTHER EXISTING SITE IMPROVEMENTS INCLUDING THE UNDERGROUND COMPONENTS AS CLARIFIED BY THIS DRAWING. IT IS THE CONTRACTOR'S RESPONSIBILITY TO FULLY REVIEW THE SITE CONDITIONS AND TO CORRELATE THESE OBSERVATIONS WITH THE PROJECT WORK AND INCLUDE ALL NECESSARY DEMOLITION, WHETHER SHOWN OR NOT, AND INCLUDE ALL SUCH COSTS IN THE SCOPE OF WORK. 2.CLEARING: IT IS THE INTENT UNDER THE WORK OF THIS CONTRACT TO CONDUCT ALL CLEARING NECESSARY TO BE ABLE TO COMPLETE ALL THE WORK OF THIS PROJECT. 3.CONTRACTOR SHALL LEGALLY DISPOSE ALL DEMOLISHED AND REMOVED MATERIALS OFF THE OWNER'S PROPERTY UNLESS INDICATED OTHERWISE. 4.IT IS THE RESPONSIBILITY OF THE CONTRACTOR TO COMPLETELY COORDINATE UTILITY DEMOLITION WITH NEW CONSTRUCTION. CONTRACTOR SHALL ENSURE THAT ADEQUATE FIRE PROTECTION IN ACCORDANCE WITH THE FIRE MARSHAL'S REQUIREMENTS IS PROVIDED FOR EXISTING BUILDINGS. 5.ALL WORK SHALL BE CONTAINED WITHIN THE CONSTRUCTION LIMITS SHOWN ON THIS DRAWING. NO ADJOINING AREAS SHALL BE DISTURBED BY CONSTRUCTION ACTIVITIES. 6.CONTRACTOR TO PROVIDE ADEQUATE MEASURES TO MINIMIZE THE AMOUNT OF SEDIMENT TRANSPORTED ONTO PAVED ROADS FROM MOTOR VEHICLES LEAVING THE PROJECT SITE. DEPOSITED SEDIMENT SHALL BE CLEANED EVERY DAY BY SHOVELING OR SWEEPING. WATER CLEANING SHALL ONLY BE DONE AFTER THE AREA HAS BEEN SHOVELED OUT OR SWEPT. 7.CONTRACTOR TO PROTECT EXISTING UTILITIES UNLESS OTHERWISE NOTED. DEMOLITION NOTES FILTER FABRIC FENCE CLEARING LIMITS FF CL INLET SEDIMENT PROTECTION ASPHALT PAVEMENT REMOVAL CONCRETE PAVEMENT REMOVAL TESC & DEMOLITION LEGEND SAWCUT LINESL IP 1 C1.1 2 C1.1GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 N PROTECT EXISTING CATCH BASIN SW 7TH STREET EXISTING BUILDING 66,786 SF BUILDING ADDITION 6,386 SF EXISTING BUILDING 1,680 SF CHAIN LINK FENCE REFER TO ARCHITECTURAL STAIR REFER TO ARCHITECTURAL FREEZER COMPRESSOR ON 30' x 10' CONCRETE PAD. REFER TO MECHANICAL AND ARCHITECTURAL. ROOF DOWNSPOUT PROVIDE SPLASH BLOCK TO EXISTING PAVEMENT ROOF DOWNSPOUT PROVIDE SPLASH BLOCK TO EXISTING PAVEMENT MATCH EXISTING PAVEMENT ELEVATION EXISTING CATCH BASIN EXISTING CATCH BASIN Sheet No.Designed by:Drawn by:Checked by:Sheet Title:Revisions:Issue Set & Date:Client:Job No.of Sheets123Project Title:535 DOCK ST, SUITE 211, TACOMA, WA 98402TEL: 253.284.9680 FAX:253.284.9681WWW.TAHOMADESIGNGROUP.COMTAHOMADESIGN GROUPNorthwest Gourmet Foods - Freezer Addition 600 SW 7th St, Renton, WA 98057 Northwest Gourmet FoodsFreezer AdditionNorthwest Gourmet Foods600 SW 7th St, Renton, WA 98057Mike Gilroy (425) 793-5001Issue For ClientReview9/4/20182160966.10DRAINAGE ANDSURFACING PLANTDWTDWSTKC1.12215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB TACOMA SEATTLE SPOKANE TRI-CITIES GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 N ASPHALT PAVEMENT CONCRETE PAVEMENT (PER STRUCTURAL) SURFACING LEGEND 3 C1.1 SW 7TH STREET REFER TO ARCHITECTURAL PLANS FOR HORIZONTAL CONTROL INFORMATION. STORMWATER RUNOFF FROM THE BUILDING ROOF WILL SPLASH BLOCK ONTO PAVEMENT AND DRAIN TO EXISTING CATCH BASINS. STORMWATER RUNOFF FROM THE COMPRESSOR PAD AND GRAVEL WILL SHEET FLOW TO THE EXISTING LAWN AREA, USING BASIC DISPERSION. NOTE PROVIDE GRAVEL SURFACING INSIDE CHAIN LINK FENCE MATCH EXISTING FINISH FLOOR AREA DISTURBED:7,632 SF REPLACED IMPERVIOUS SURFACE:6,386 SF (BUILDING) 334 SF (PAVEMENT) NEW IMPERVIOUS SURFACE:300 SF (COMPRESSOR PAD) 612 SF (GRAVEL) PROJECT STATISTICS Sheet No.Designed by:Drawn by:Checked by:Sheet Title:Revisions:Issue Set & Date:Client:Job No.of Sheets123Project Title:535 DOCK ST, SUITE 211, TACOMA, WA 98402TEL: 253.284.9680 FAX:253.284.9681WWW.TAHOMADESIGNGROUP.COMTAHOMADESIGN GROUPNorthwest Gourmet Foods - Freezer Addition 600 SW 7th St, Renton, WA 98057 Northwest Gourmet FoodsFreezer AdditionNorthwest Gourmet Foods600 SW 7th St, Renton, WA 98057Mike Gilroy (425) 793-5001Issue For ClientReview9/4/20182160966.10NOTES AND DETAILSTDWTDWSTKC1.22215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB TACOMA SEATTLE SPOKANE TRI-CITIES PROVIDE HERBICIDE TREATMENT NOTE : 1.ALL DEPTHS SHOWN ARE COMPACTED DEPTHS. 2.PREPARE SUBGRADE PER GEOTECHNICAL RECOMMMENDATIONS. COMPACTED SUBGRADE TO 95% 30" MINIMUM CRUSHED SURFACING TOP COURSE PER WSDOT STANDARD SPECIFICATION 9-03.9(3) HMA CLASS 1/2", PG 64-22 PER WSDOT STANDARD SPECIFICATION 5-04 6" 3" 1 NOT TO SCALE FILTER FABRIC FENCE 2 NOT TO SCALE INLET SEDIMENT PROTECTION 3 NOT TO SCALE ASPHALT PAVEMENT SECTION Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendix B Recommended BMPs CITY OF RENTON SURFACE WATER DESIGN MANUAL 2017 City of Renton Surface Water Design Manual 12/12/2016 D-9 D.2 GENERAL CSWPP REQUIREMENTS To satisfy the City of Renton’s requirements for CSWPP, the following steps are required of all construction projects: 1. Design the plan: In accordance with Sections 2.3.1 and 2.3.3 of the SWDM, prepare and submit a technical information report (TIR) and a CSWPP plan (comprised of the ESC plan and the SWPPS plan) for City review. Utilize the standards and details for ESC (Section D.2.1) and SWPPS control (Section D.2.2) of this appendix. Incorporate any City of Renton review comments as necessary to comply with Core Requirement #5, Section 1.2.5 of the SWDM, the Erosion and Sediment Control and Stormwater Pollution Prevention and Spill Control Standards in this appendix. 2. Construct the approved plan: Construct initial ESC, SWPPS and stormwater facility (flow control facility, runoff treatment facility, and on-site BMP) protection measures on site according to the approved CSWPP plan. 3. Maintain the BMPs: Inspect and maintain all CSWPP measures and stormwater facility (flow control facility, runoff treatment facility, and on-site BMP) protection throughout construction in accordance with the inspection and maintenance standards of Section D.2.4.4. Keep current any required documentation and reporting. 4. Manage the project: Make any changes or additions necessary during construction to ensure that CSWPP measures and stormwater facility (flow control facility, runoff treatment facility, and on-site BMP) protection perform in accordance with Core Requirement #5 and Sections D.2.1, D.2.2 and D.2.4. Coordinate construction in consideration of the applied BMP strategies. Ensure pollutant controls, facility processes and reporting requirements are met in accordance with Section D.2.3. The CSWPP supervisor is the primary point of contact for all ESC and SWPPP issues (see Section D.2.3.1). 5. Conclude the plan: Prior to final construction approval, meet all the conditions in Section D.2.4.5 for final stabilization. A National Pollutant Discharge Elimination System (NPDES) General Permit for Construction (pursuant to the Washington State Department of Ecology’s Construction Stormwater General Permit) may also be required for projects that will disturb one or more acres (see SWDM Section 1.2.5.3 for additional information). Proposed projects subject to Simplified Drainage Review as determined in SWDM Section 1.1.2.1 may satisfy City of Renton CSWPP requirements by meeting the Small Site CSWPP requirements specified in Section D.3 and reiterated in Appendix C of the SWDM titled, “Simplified Drainage Requirements.” D.2.1 ESC MEASURES This section details the ESC measures that are required to minimize erosion and sediment transport off a construction site and protect areas of existing and proposed stormwater facilities (flow control facilities, runoff treatment facilities, and on-site BMPs). These ESC measures represent Best Management Practices (BMPs)6 for the control of erosion and entrained sediment as well as other impacts related to construction such as increased runoff due to land disturbing activities. The measures and practices are grouped into nine sections corresponding to each of the nine categories of ESC measures in Core Requirement #5, Section 1.2.5 of the SWDM. The introductory paragraphs at the beginning each section present the basic requirement for that category of measures, the purpose of those measures, installation requirements relative to construction activity, guidelines for the conditions of use, and other information relevant to all measures in the section/category. Compliance with each of the nine categories of the ESC measures, to the 6 Best Management Practices (BMPs) means the best available and reasonable physical, structural, managerial, or behavioral activities, that when singly or in combination, eliminate or reduce the contamination of surface and/or ground waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-10 extent applicable and necessary to meet the performance criteria in Section D.2.1, and compliance with the ESC implementation requirements in Section D.2.4, constitutes overall compliance with the City’s ESC Standards. Note: Additional measures shall be required by the City if the existing standards are insufficient to protect adjacent properties, drainage facilities, or water resources. The standards for each individual ESC measure are divided into four sections: 1. Purpose 2.Conditions of Use 3.Design and Installation Specifications 4.Maintenance Requirements. A code and symbol for each measure have also been included for ease of use on ESC plans. Note that the “Conditions of Use” always refers to site conditions. As site conditions change, ESC measures must be changed to remain in compliance with the requirements of this appendix. Whenever compliance with the City’s ESC Standards is required, all of the following categories of ESC measures must be considered for application to the project site as detailed in the following sections: 1.Clearing Limits: Prior to any site clearing or grading, areas to remain undisturbed during project construction shall be delineated on the project’s ESC plan and physically marked on the project site. 2.Cover Measures: Temporary and permanent cover measures shall be provided when necessary to protect disturbed areas. The intent of these measures is to prevent erosion by having as much area as possible covered during any period of precipitation. 3.Perimeter Protection: Perimeter protection to filter sediment from sheet flow shall be provided downstream of all disturbed areas prior to upslope grading. 4.Traffic Area Stabilization: Unsurfaced entrances, roads, and parking areas used by construction traffic shall be stabilized to minimize erosion and tracking of sediment offsite. 5.Sediment Retention: Surface water collected from all disturbed areas of the site shall be routed through a sediment pond or trap prior to release from the site, except those areas at the perimeter of the site small enough to be treated solely with perimeter protection. Sediment retention facilities shall be installed prior to grading any contributing area. 6.Surface Water Collection: Surface water collection measures (e.g., ditches, berms, etc.) shall be installed to intercept all surface water from disturbed areas, convey it to a sediment pond or trap, and discharge it downstream of any disturbed areas. Areas at the perimeter of the site, which are small enough to be treated solely with perimeter protection, do not require surface water collection. Significant sources of upstream surface water that drain onto disturbed areas shall be intercepted and conveyed to a stabilized discharge point downstream of the disturbed areas. Surface water collection measures shall be installed concurrently with or immediately following rough grading and shall be designed, constructed, and stabilized as needed to minimize erosion. 7.Dewatering Control: The water resulting from construction site de-watering activities must be treated prior to discharge or disposed of as specified. 8.Dust Control: Preventative measures to minimize wind transport of soil shall be implemented when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources. 9.Flow Control: Surface water from disturbed areas must be routed through the project’s onsite flow control facility or other provisions must be made to prevent increases in the existing site conditions 2-year and 10-year runoff peaks discharging from the project site during construction (flow control D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-11 facility, runoff treatment facility, and on-site BMP areas [existing or proposed] shall not be used for this purpose). 10. Control Pollutants: Stormwater pollution prevention (SWPPS) measures are required to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses from construction-related activities such as materials delivery and storage, onsite equipment fueling and maintenance, demolition of existing buildings and disposition of demolition materials and other waste, and concrete handling, washout and disposal. Section D.2.2 describes BMPs specific to this purpose; additionally, several of the ESC BMPs described herein are applicable. 11. Protect Existing and Proposed Stormwater Facilities and On-site BMPs: Sedimentation and soil compaction reduce the infiltration capacity of native and engineered soils. Protection measures shall be applied/installed and maintained so as to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed stormwater facilities and on-site BMPs for the project. Adverse impacts can prompt the requirement to restore or replace affected stormwater facilities and on-site BMPs. 12. Maintain Protective BMPs: Protection measures shall be maintained to ensure continued performance of their intended function, to prevent adverse impacts to existing BMPs/facilities and areas of proposed BMPs/facilities, and protect other disturbed areas of the project. 13. Manage the Project: Coordination and timing of site development activities relative to ESC concerns, and timely inspection, maintenance and update of protective measures are necessary to effectively manage the project and ensure the success of protective ESC and SWPPS design and implementation. D.2.1.1 CLEARING LIMITS Prior to any site clearing or grading, those areas that are to remain undisturbed during project construction shall be delineated. At a minimum, clearing limits shall be installed at the edges of all critical area buffers and any other areas required to be left uncleared such as portions of the site subject to clearing limits under RMC 4-4-060, areas around significant trees identified to be retained, on-site BMP areas to be protected, and other areas identified to be left undisturbed to protect sensitive features. Purpose: The purpose of clearing limits is to prevent disturbance of those areas of the project site that are not designated for clearing or grading. This is important because limiting site disturbance is the single most effective method for reducing erosion. Clearing limits may also be used to control construction traffic, thus reducing the disturbance of soil and limiting the amount of sediment tracked off site. When to Install: Clearing limits shall be installed prior to the clearing and/or grading of the site. Measures to Use: Marking clearing limits by delineating the site with a continuous length of brightly colored survey tape is sometimes sufficient. The tape may be supported by vegetation or stakes, and it shall be 3 to 6 feet high and highly visible. Critical areas and their buffers require more substantial protection and shall be delineated with plastic or metal safety fences or stake and wire fences. Fencing may be required at the City’s discretion to control construction traffic or at any location where greater protection is warranted. Permanent fencing may also be used if desired by the applicant. Silt fence, in combination with survey flagging, is also an acceptable method of marking critical areas and their buffers. D.2.1.1.1 PLASTIC OR METAL FENCE Code: FE Symbol: Purpose Fencing is intended to (1) restrict clearing to approved limits; (2) prevent disturbance of critical areas, their buffers, and other areas required to be left undisturbed; (3) limit construction traffic to designated construction entrances or roads; and (4) protect areas where marking with survey tape may not provide adequate protection. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-12 Conditions of Use To establish clearing limits, plastic or metal fence may be used: 1. At the boundary of critical areas, their buffers, and other areas required to be left uncleared. 2. As necessary to control vehicle access to and on the site (see Sections D.2.1.4.1 and D.2.1.4.2). Design and Installation Specifications 1. The fence shall be designed and installed according to the manufacturer’s specifications. 2. The fence shall be at least 3 feet high and must be highly visible. 3. The fence shall not be wired or stapled to trees. Maintenance Requirements 1. If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. 2. Disturbance of a critical area, critical area buffer, native growth retention area, or any other area required to be left undisturbed shall be reported to the City for resolution. D.2.1.2 COVER MEASURES Temporary and permanent cover measures shall be provided to protect all disturbed areas, including the faces of cut and fill slopes. Temporary cover shall be installed if an area is to remain unworked for more than seven days during the dry season (May 1 to September 30) or for more than two consecutive working days during the wet season (October 1 to April 30). These time limits may be relaxed if an area poses a low risk of erosion due to soil type, slope gradient, anticipated weather conditions, or other factors. Conversely, the City may reduce these time limits if site conditions warrant greater protection (e.g., adjacent to significant aquatic resources or highly erosive soils) or if significant precipitation (see Section D.2.4.2) is expected. Any area to remain unworked for more than 30 days shall be seeded or sodded, unless the City determines that winter weather makes vegetation establishment infeasible. During the wet season, slopes and stockpiles at 3H:1V or steeper and with more than ten feet of vertical relief shall be covered if they are to remain unworked for more than 12 hours. Also during the wet season, the material necessary to cover all disturbed areas must be stockpiled on site. The intent of these cover requirements is to have as much area as possible covered during any period of precipitation. Purpose: The purpose of covering exposed soils is to prevent erosion, thus reducing reliance on less effective methods that remove sediment after it is entrained in runoff. Cover is the only practical method of reducing turbidity in runoff. Structural measures, such as silt fences and sediment ponds, are only capable of removing coarse particles and in most circumstances have little to no effect on turbidity. When to Install: Any exposed soils that will remain unworked for more than the time limit set above shall be covered by the end of the working day. If the exposed area is to remain unworked for more than 30 days, the area shall be seeded with the temporary seed mix or an equivalent mix that will provide rapid protection (see Section D.2.1.2.6). If the disturbed area is to remain unworked for a year or more or if the area has reached final grade, permanent seed mix or an equivalent mix shall be applied. Measures to Use: Cover methods include the use of surface roughening, mulch, erosion control nets and blankets, plastic covering, seeding, and sodding. Mulch and plastic sheeting are primarily intended to protect disturbed areas for a short period of time, typically days to a few months. Seeding and sodding are measures for areas that are to remain unworked for months. Erosion nets and blankets are to be used in conjunction with seeding steep slopes. The choice of measures is left to the designer; however, there are restrictions on the use of these methods, which are listed in the “Conditions of Use” and the “Design and Installation Specifications” sections for each measure. The methods listed are by no means exhaustive. Variations on the standards presented here are encouraged if other cost-effective products or methods provide substantially equivalent or superior performance. Also, D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-15 D.2.1.2.2 MULCHING Code: MU Symbol: Purpose The purpose of mulching soils is to provide 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 may be used. Only the most common types are discussed in this section. Conditions of Use As a temporary cover measure, mulch should be used: 1. On disturbed areas that require cover measures for less than 30 days 2. As a cover for seed during the wet season and during the hot summer months 3. During the wet season on slopes steeper than 3H:1V with more than 10 feet of vertical relief. Design and Installation Specifications For mulch materials, application rates, and specifications, see Table D.2.1.2.A. Note: Thicknesses may be increased for disturbed areas in or near critical areas or other areas highly susceptible to erosion. Maintenance Standards 1. The thickness of the cover must be maintained. 2. 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 drainage problem shall be assessed and alternate drainage such as interceptor swales may be needed to fix the problem and the eroded area remulched. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-16 TABLE D.2.1.2.A 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. Straw should be crimped to avoid wind blow. The thickness of straw may be reduced by half when used in conjunction with seeding. Wood Fiber Cellulose 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. Some wood fiber with very long fibers can be effective at lower application rates and without seed or tackifier. Compost No visible water or dust during handling. Must be purchased from supplier with Solid Waste Handling Permit. 2″ thick min.; approx. 100 tons per acre (approx. 1.5 cubic feet per square yard) More effective control can be obtained by increasing thickness to 3″ (2.25 cubic feet per square yard). Excellent mulch for protecting final grades until landscaping because it can be directly seeded or tilled into soil as an amendment. Compost may not be used in Sensitive Lake 7 basins unless analysis of the compost shows no phosphorous release. Hydraulic Matrices (Bonded Fiber Matrix [BFM]) This mulch category includes hydraulic slurries composed of wood fiber, paper fiber or a combination of the two held together by a binding system. The BFM shall be a mixture of long wood fibers and various bonding agents. Apply at rates from 3,000 lbs per acre to 4,000 lbs per acre and based on manufacturers recommendations The BFM shall not be applied immediately before, during or immediately after rainfall so that the matrix will have an opportunity to dry for 24 hours after installation. Application rates beyond 2,500 pounds may interfere with germination and are not usually recommended for turf establishment. BFM is generally a matrix where all fiber and binders are in one bag, rather than having to mix components from various manufacturers to create a matrix. BFMs can be installed via helicopter in remote areas. They are approximately $1,000 per acre cheaper to install. Chipped Site Vegetation Average size shall be several inches. 2″ minimum thickness 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. 7 Sensitive lake means a lake that has proved to be particularly prone to eutrophication; the City did not have any lakes that had this designation at the time of SWDM adoption. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-23 D.2.1.2.6 TEMPORARY AND PERMANENT SEEDING Code: SE Symbol: Purpose Seeding is intended to reduce erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use 1. Seeding shall be used throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. 2. Vegetation-lined channels shall be seeded. Channels that will be vegetated should be installed before major earthwork and hydroseeded or covered with a Bonded Fiber Matrix (BFM). 3. Retention/detention ponds shall be seeded as required. 4. At the City’s discretion, seeding without mulch during the dry season is allowed even though it will take more than seven days to develop an effective cover. Mulch is, however, recommended at all times because it protects seeds from heat, moisture loss, and transport due to runoff. 5. Prior to the beginning of the wet season, all disturbed areas shall be reviewed to identify which ones can be seeded in preparation for the winter rains (see Section D.2.4.2). Disturbed areas shall be seeded within one week of the beginning of the wet season. A sketch map of those areas to be seeded and those areas to remain uncovered shall be submitted to the CED inspector. The CED inspector may require seeding of additional areas in order to protect surface waters, adjacent properties, or drainage facilities. 6. At final site stabilization, all disturbed areas not otherwise vegetated or stabilized shall be seeded and mulched (see Section D.2.4.5). Design and Installation Specifications 1. The best time to seed is fall (late September to October) or in spring (mid-March to June). Irrigation is required during the first summer following installation if seeding occurs in spring or summer or during prolonged dry times of year. Areas may also be seeded during the winter months, but it may take additional spring seeding applications to develop a dense groundcover due to cold temperatures. The application and maintenance of mulch is critical for winter seeding. 2. To prevent seed from being washed away, confirm that all required surface water control measures have been installed. 3. The seedbed should not be compacted because soils that are well compacted will not vegetate as quickly or thoroughly. Slopes steeper than 3H:1V shall be surface roughened. Roughening can be accomplished in a variety of ways, but the typical method is track walking, or driving a crawling tractor up and down the slope, leaving cleat imprints parallel to the slope contours. 4. In general, 10-20-20 N-P-K (nitrogen-phosphorus-potassium) fertilizer may be used at a rate of 90 pounds per acre. Slow-release fertilizers are preferred because they are more efficient and have fewer environmental impacts. It is recommended that areas being seeded for final landscaping conduct soil tests to determine the exact type and quantity of fertilizer needed. This will prevent the over- application of fertilizer. Disturbed areas within 200 feet of water bodies and wetlands must use slow- release low-phosphorus fertilizer (typical proportions 3-1-2 N-P-K). 5. The following requirements apply to mulching: a) Mulch is always required for seeding slopes greater than 3H:1V (see Section D.2.1.2.2). b) If seeding during the wet season, mulch is required. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-24 c) The use of mulch may be required during the dry season at the City’s discretion if grass growth is expected to be slow, the soils are highly erodible due to soil type or gradient, there is a water body close to the disturbed area, or significant precipitation (see Section D.2.4.2) is anticipated before the grass will provide effective cover. d) Mulch may be applied on top of the seed or simultaneously by hydroseeding. 6. Hydroseeding is allowed as long as tackifier is included. Hydroseeding with wood fiber mulch is adequate during the dry season. Application of hydroseeded wood fiber mulch should be appropriate for slope angle. Follow manufacturer specifications for application rates. 7. Areas to be permanently landscaped shall use soil amendments. Good quality topsoil shall be tilled into the top six inches to reduce the need for fertilizer and improve the overall soil quality. Most native soils will require the addition of four inches of well-rotted compost to be tilled into the soil to provide a good quality topsoil. Compost used should meet specifications provided in Reference Section 11-C of the SWDM. 8. The seed mixes listed below include recommended mixes for both temporary and permanent seeding. These mixes, with the exception of the wetland mix, shall be applied at a rate of 80 to 100 seeds per square foot. Wet sites should apply 120 to 150 seeds per square foot. Local suppliers should be consulted for information on current Pure Live Seed (PLS) rates and species specific seeds per pound in order to determine seed mix PLS pounds of seed per acre. The appropriate mix depends on a variety of factors, including exposure, soil type, slope, and expected foot traffic. Alternative seed mixes approved by the City may be used. Table D.2.1.2.B presents the standard mix for those areas where t a temporary or permanent vegetative cover is required. The following mix assumes a desired 150 seeds per square foot and should be applied at approximately 37 pounds of pure live seed per acre. TABLE D.2.1.2.B EROSION CONTROL SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Spike bentgrass/Agrostis exarata 6 9 0.1 California brome/Bromus carinatus 15 23 9.8 Tufted hairgrass/Deschampsia cespitosa 15 23 0.4 Blue wildrye/Elymus glaucus 18 27 10.7 California oatgrass/Danthonia californica 18 27 5.6 Native red fescue/Festuca rubra var. rubra 18 27 2.4 Meadow barley/Hordeum brachyantherum 10 15 7.7 Table D.2.1.2.C provides just one recommended possibility for landscaping seed. It assumes a desired 100 seeds per square foot and should be applied at 12 pounds of pure live seed per acre. TABLE D.2.1.2.C LANDSCAPING SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Sideoats grama/Bouteloua curtipendula 20 30 6.8 California oatgrass/Danthonia californica 20 30 6.2 Native red fescue/Festuca rubra var. rubra 30 45 3.9 Prairie junegrass/Koeleria macrantha 30 45 0.8 D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-25 This turf seed mix in Table D.2.1.2.D is for dry situations where there is no need for much water. The advantage is that this mix requires very little maintenance. TABLE D.2.1.2.D LOW-GROWING TURF SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Hard fescue/Festuca brevipila 25 20 1.5 Sheep fescue/Festuca ovina 30 24 1.5 Native red fescue/Festuca rubra var. rubra 25 20 1.7 Prairie junegrass/Koeleria macrantha 20 16 0.3 Table D.2.1.2.E presents a mix recommended for bioswales and other intermittently wet areas. The mix assumes a desired 150 seeds per square foot and approximately 29 pounds of pure live seed per acre. Sod shall generally not be used for bioswales because the seed mix is inappropriate for this application. Sod may be used for lining ditches to prevent erosion, but it will provide little water quality benefit during the wet season. TABLE D.2.1.2.E BIOSWALE SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre American sloughgrass/Beckmannia syzigachne 15 23 0.9 Tufted hairgrass/Deschampsia cespitosa 20 30 0.5 Blue wildrye/Elymus glaucus 18 27 10.7 Native red fescue/Festuca rubra var. rubra 20 30 2.6 Meadow barley/Hordeum brachyantherum 12 18 9.2 Northwestern mannagrass/Glyceria occidentalis 15 23 4.9 The seed mix shown in Table D.2.1.2.F is a recommended low-growing, non-invasive seed mix appropriate for very wet areas that are not regulated wetlands (if planting in wetland areas, see Section 6.3.1 of the SWDM). Other mixes may be appropriate, depending on the soil type and hydrology of the area. This mixture assumes a target goal of 150 seeds per square foot and should be applied at a rate of 36 pounds per acre. TABLE D.2.1.2.F WET AREA SEED MIX* Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre California brome/Bromus carinatus 15 23 9.8 Columbia brome/Bromus vulgaris 18 27 8.1 Tufted hairgrass/Deschampsia cespitosa 15 23 0.4 California oatgrass/Danthonia californica 15 23 4.7 Native red fescue/Festuca rubra var. rubra 17 26 2.2 Western manna grass/Glyceria occidentalis 10 15 3.3 Meadow barley/Hordeum brachyantherum 10 15 7.7 * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-26 The meadow seed mix in Table D.2.1.2.G is recommended for areas that will be maintained infrequently or not at all and 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. This seed mix assumes a target goal of 120 seeds per square foot and an application rate of 23 pounds of pure live seed per acre. TABLE D.2.1.2.G MEADOW SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Common yarrow/Achillea millefolium 4 5 0.1 Pearly everlasting/Anaphalis margartacae 1 1 0.0 California brome/Bromus carinatus 15 18 7.8 California oatgrass/Danthonia californica 15 18 3.7 Blue wildrye/Elymus glaucus 16 19 7.6 Festuca idahoensis 15 18 1.7 Native red fescue/Festuca rubra var. rubra 18 22 1.9 Sickle keeled lupine/Lupinus albicaulis 1 1 2.2 Fowl bluegrass/Poa palustris 15 18 0.4 Maintenance Standards for Temporary and Permanent Seeding 1. Any seeded areas that fail to establish at least 80 percent cover within one month shall be reseeded. If reseeding is ineffective, an alternate method, such as sodding or nets/blankets, shall be used. If winter weather prevents adequate seed establishment and growth, this time limit may be relaxed at the discretion of the City when critical areas would otherwise be protected. 2. After adequate cover is achieved, any areas that experience erosion shall be re-seeded and protected by mulch. If the erosion problem is drainage related, the problem shall be fixed and the eroded area re- seeded and protected by mulch. 3. Seeded areas shall be supplied with adequate moisture, but not watered to the extent that it causes runoff. D.2.1.2.7 SODDING Code: SO Symbol: Purpose The purpose of sodding is to establish permanent turf for immediate erosion protection and to stabilize drainage ways where concentrated overland flow will occur. Conditions of Use Sodding may be used in the following areas: 1. Disturbed areas that require short-term or long-term cover 2. Disturbed areas that require immediate vegetative cover 3. All waterways that require vegetative lining (except biofiltration swales—the seed mix used in most sod is not appropriate for biofiltration swales). Waterways may also be seeded rather than sodded, and protected with a net or blanket (see Section D.2.1.2.3). SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-30 • Provide immediate temporary protection from erosion by protecting soil from rainfall and slowing flow velocity over the soil surface. • Enhance temporary or permanent plant establishment by conserving moisture, holding seed and topsoil in place, providing nutrients and soil microorganisms, and moderating soil temperatures. • Compost blankets, applied at the proper thickness and tilled into the soil, are also an option for amending soils for permanent landscaping. • Compost generally releases and adds phosphorous to stormwater. Therefore, compost blankets are not recommended for use in watersheds where phosphorous sensitive water resources are located. Unless prior approval is given by the City, they should not be used in Sensitive Lake Watersheds. Conditions of Use 1. Compost blankets may be used unseeded on disturbed areas that require temporary cover measures up to 1 year. Compost applied as temporary cover may be reclaimed and re-used for permanent cover. 2. Compost provides cover for protecting final grades until landscaping can be completed as it can be directly seeded or tilled into soil as an amendment. 3. Compost blankets meet mulch requirements for seed. 4. Seed may be applied to a compost blanket at any time for permanent or temporary stabilization of disturbed areas. Seed may be applied prior to blanket application, on top of blankets, or injected and mixed into the compost as it is applied. 5. Compost blankets may be applied on slopes up to 2H:1V. Design and Installation Specifications 1. Compost shall be applied at a minimum of 2 inches thick, unless otherwise directed by an ESC supervisor or the City. At an application of 2 inches, this will equal approximately 100 tons per acre (compost generally weighs approximately 800 lbs per cubic yard). Thickness shall be increased at the direction of the design engineer for disturbed areas in or near critical areas or other areas highly susceptible to erosion. 2. Compost shall meet criteria in Reference Section 11-C of the SWDM. 3. Compost shall be obtained from a supplier meeting the requirements in Reference Section 11-C. 4. Compost blankets shall be applied over the top of the slope to which it is applied, to prevent water from running under the blanket 5. Compost blankets shall not be used in areas exposed to concentrated flow (e.g., channels, ditches, dikes) Maintenance Standards 1. The specified thickness of the blanket/cover must be maintained. 2. Any areas that show signs of erosion must be re-mulched. If the erosion problem is drainage related, then the drainage problem must first be remedied and then the eroded area re-mulched. D.2.1.3 PERIMETER PROTECTION Perimeter protection to filter sediment from sheetwash shall be located downslope of all disturbed areas and shall be installed prior to upslope grading. Perimeter protection includes the use of vegetated strips as well as, constructed measures, such as silt fences, fiber rolls, sand/gravel barriers, brush or rock filters, triangular silt dikes and other methods. During the wet season, 50 linear feet of silt fence (and the necessary stakes) per acre of disturbed area must be stockpiled on site. Purpose: The purpose of perimeter protection is to reduce the amount of sediment transported beyond the disturbed areas of the construction site. Perimeter protection is primarily a backup means of sediment control. Most, if not all, sediment-laden water is to be treated in a sediment trap or pond. The only D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-31 circumstances in which perimeter control is to be used as a primary means of sediment removal is when the catchment is very small (see below). When to Install: Perimeter protection is to be installed prior to any upslope clearing and grading. Measures to Use: The above measures may be used interchangeably and are not the only perimeter protection measures available. If surface water is collected by an interceptor dike or swale and routed to a sediment pond or trap, there may be no need for the perimeter protection measures specified in this section. Criteria for Use as Primary Treatment: At the boundary of a site, perimeter protection may be used as the sole form of treatment when the flowpath meets the criteria listed below. If these criteria are not met, perimeter protection shall only be used as a backup to a sediment trap or pond. Average Slope Slope Percent Flowpath Length 1.5H:1V or less 67% or less 100 feet 2H:1V or less 50% or less 115 feet 4H:1V or less 25% or less 150 feet 6H:1V or less 16.7% or less 200 feet 10H:1V or less 10% or less 250 feet D.2.1.3.1 SILT FENCE Code: SF Symbol: 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. Conditions of Use 1. Silt fence may be used downslope of all disturbed areas. 2. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a silt fence, rather than by a sediment trap or pond, is when the area draining to the fence is small (see “Criteria for Use as Primary Treatment” in Section D.2.1.3 above). Design and Installation Specifications 1. See Figure D.2.1.3.A and Figure D.2.1.3.B for details. 2. The geotextile used must meet the standards listed below. A copy of the manufacturer’s fabric specifications must be available on site. AOS (ASTM D4751) 30–100 sieve size (0.60–0.15 mm) for slit film 50–100 sieve size (0.30–0.15 mm) for other fabrics Water Permittivity (ASTM D4491) 0.02 sec-1 minimum Grab Tensile Strength (ASTM D4632) (see Specification Note 3) 180 lbs. min. for extra strength fabric 100 lbs. min. for standard strength fabric Grab Tensile Elongation (ASTM D4632) 30% max. (woven) Ultraviolet Resistance (ASTM D4355) 70% min. 3. Standard strength fabric requires wire backing to increase the strength of the fence. Wire backing or closer post spacing may be required for extra strength fabric if field performance warrants a stronger fence. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-32 4. Where the fence is installed, the slope shall be no steeper than 2H:1V. 5. If a typical silt fence (per Figure D.2.1.3.A) is used, the standard 4 x 4 trench may not be reduced as long as the bottom 8 inches of the silt fence is well buried and secured in a trench that stabilizes the fence and does not allow water to bypass or undermine the silt fence. Maintenance Standards 1. Any damage shall be repaired immediately. 2. If concentrated flows are evident uphill of the fence, they must be intercepted and conveyed to a sediment trap or pond. 3. It is important to check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. 4. Sediment must be removed when the sediment is 6 inches high. 5. If the filter fabric (geotextile) has deteriorated due to ultraviolet breakdown, it shall be replaced. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-33 FIGURE D.2.1.3.A SILT FENCE 2"X2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED NOTE: FILTER FABRIC FENCES SHALL BE INSTALLED ALONG CONTOURS WHENEVER POSSIBLE JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS OR EQUIVALENT TO ATTACH FABRIC TO POSTS. FILTER FABRIC BACKFILL TRENCH WITH NATIVE SOIL OR 3/4" TO 1-1/2" WASHED GRAVEL MINIMUM 4"x4" TRENCH 2"x4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUIVALENT POST SPACING MAY BE INCREASED TO 8' IF WIRE BACKING IS USED 6' MAX.2' MIN.12" MIN. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-34 FIGURE D.2.1.3.B SILT FENCE INSTALLATION BY SLICING 1.GATHER FABRIC AT POSTS, IF NEEDED. 2.UTILIZE THREE TIES PER POST, ALL WITHIN TOP 8" OF FABRIC. 3.POSITION EACH TIE DIAGONALLY, PUNCTURING HOLES VERTICALLY A MINIMUM OF 1" APART. 4.HANG EACH TIE ON A POST NIPPLE AND TIGHTEN SECURELY. USE CABLE TIES (50 LBS) OF SOFT WIRE. TOP OF FABRIC BELT DIAGONAL ATTACHMENT DOUBLES STRENGTH FLOW STEEL SUPPORT POST1.POST SPACING: 7' MAX. ON OPEN RUNS 4' MAX. ON POOLING AREAS. 2.POST DEPTH: AS MUCH BELOW GROUND AS FABRIC ABOVE GROUND. 3.PONDING HEIGHT MAX. 24" ATTACH FABRIC TO UPSTREAM SIDE OF POST. 4.DRIVE OVER EACH SIDE OF SILT FENCE 2 TO 4 TIMES WITH DEVICE EXERTING 60 P.S.I. OR GREATER. 5.NO MORE THAN 24" OF A 36" FABRIC IS ALLOWED ABOVE GROUND. 6.VIBRATORY PLOW IS NOT ACCEPTABLE BECAUSE OF HORIZONTAL COMPACTION. 100% COMPACTION EACH SIDE OPERATION ROLL OF SILT FENCE PLOW FABRIC ABOVE GROUND HORIZONTAL CHISEL POINT (76 mm WIDTH)200-300mm SILT FENCE TOP 8" NOTES: ATTACHMENT DETAILS: SILT FENCE INSTALLATION BY SLICING METHOD NTS SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-52 FIGURE D.2.1.5.D SEDIMENT POND RISER DETAIL D.2.1.5.3 STORM DRAIN INLET PROTECTION Code: FFP or CBI or CBP Symbol: or or Purpose Storm drain inlets are protected to prevent coarse sediment from entering storm drainage systems. Temporary devices around storm drains assist in improving the quality of water discharged to inlets or catch basins by ponding sediment-laden water. These devices are effective only for relatively small drainage areas. Conditions of Use 1. Protection shall be provided for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin will be conveyed to a sediment pond or trap. 2. Inlet protection may be used anywhere at the applicant’s discretion to protect the drainage system. This will, however, require more maintenance, and it is highly likely that the drainage system will still require some cleaning. 3. The contributing drainage area must not be larger than one acre. Design and Installation Specifications 1. There are many options for protecting storm drain inlets. Two commonly used options are filter fabric protection and catch basin inserts. Filter fabric protection (see Figure D.2.1.5.E) is filter fabric (geotextile) placed over the grate. This method is generally very ineffective and requires intense maintenance efforts. Catch basin inserts (see Figure D.2.1.5.F) are manufactured devices that nest inside a catch basin. This method also requires a high frequency of maintenance to be effective. Both options provide adequate protection, but filter fabric is likely to result in ponding of water above the 3.5' MIN. 18" MIN. 2X RISER DIA. MIN. CORRUGATED METAL RISER CONCRETE BASE ALTERNATIVELY, METAL STAKES AND WIRE MAY BE USED TO PREVENT FLOTATION DEWATERING ORIFICE, SCHEDULE 40 STEEL STUB MIN. DIAMETER AS PER CALCULATIONS 6" MIN. PROVIDE ADEQUATE STRAPPING POLYETHYLENE CAP PERFORATED DEWATERING DEVICE, SEE NOTE WATERTIGHT COUPLING TACK WELD NOTE: PERFORATED CORRUGATED POLYETHYLENE (CPE) DRAINAGE TUBING, DIAMETER MIN. 2" LARGER THAN DEWATERING ORIFICE. TUBING SHALL COMPLY WITH ASTM F667 AND AASHTO M294. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-53 catch basin, while the insert will not. Thus, filter fabric is only allowed where ponding will not be a traffic concern and where slope erosion will not result if the curb is overtopped by ponded water. Trapping sediment in the catch basins is unlikely to improve the water quality of runoff if it is treated in a pond or trap because the coarse particles that are trapped at the catch basin settle out very quickly in the pond or trap. Catch basin protection normally only improves water quality where there is no treatment facility downstream. In these circumstances, catch basin protection is an important last line of defense. It is not, however, a substitute for preventing erosion. The placement of filter fabric under grates is generally prohibited and the use of filter fabric over grates is strictly limited and discouraged. 2. It is sometimes possible to construct a small sump around the catch basin before final surfacing of the road. This is allowed because it can be a very effective method of sediment control. 3. Block and gravel filters, gravel and wire mesh filter barriers, and bag barriers filled with various filtering media placed around catch basins can be effective when the drainage area is 1 acre or less and flows do not exceed 0.5 cfs. It is necessary to allow for overtopping to prevent flooding. Many manufacturers have various inlet protection filters that are very effective in keeping sediment-laden water from entering the storm drainage system. The following are examples of a few common methods. a) Block and gravel filters (Figure D.2.1.5.G) are a barrier formed around an inlet with standard concrete block and gravel, installed as follows: • Height is 1 to 2 feet above the inlet. • Recess the first row of blocks 2 inches into the ground for stability. • Support subsequent rows by placing a 2x4 through the concrete block opening. • Do not use mortar. • Lay some blocks in the bottom row on their side for dewatering the pooled water. • Place cloth or mesh with ½ inch openings over all block openings. • Place gravel below the top of blocks on slopes of 2:1 or flatter. • An alternate design is a gravel donut. b) Gravel and wire mesh filters consist of a gravel barrier placed over the top of an inlet. This structure generally does not provide overflow. Install as follows: • Cloth or comparable wire mesh with ½ inch openings is placed over inlet. • Coarse aggregate covers the cloth or mesh. • Height/depth of gravel should be 1 foot or more, 18 inches wider than inlet on all sides. c) Curb inlet protection with a wooden weir is a barrier formed around an inlet with a wooden frame and gravel, installed as follows: • Construct a frame and attach wire mesh (½ inch openings) and filter fabric to the frame. • Pile coarse washed aggregate against the wire/fabric. • Place weight on frame anchors. d) Curb and gutter sediment barriers (Figure D.2.1.5.H) consist of sandbags or rock berms (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape, installed as follows: • Bags of either burlap or woven geotextile fabric, filled with a variety of media such as gravel, wood chips, compost or sand stacked tightly allows water to pond and allows sediment to separate from runoff. • Leave a “one bag gap” in the top row of the barrier to provide a spillway for overflow. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-54 • Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 x 3 and at least 2 feet from the inlet. • Construct a horseshoe shaped sedimentation trap on the outside of the berm to sediment trap standards for protecting a culvert inlet. 4. Excavated drop inlet sediment traps are appropriate where relatively heavy flows are expected and overflow capability is needed. If emergency overflow is provided, additional end-of-pipe treatment may be required. Excavated drop inlets consist of an excavated impoundment area around a storm drain. Sediment settles out of the stormwater prior to enter the drain. Install according to the following specifications: a) The impoundment area should have a depth of 1 to 2 feet measured from the crest of the inlet structure. b) Side slopes of the excavated area must be no steeper than 2:1. c) Minimum volume of the excavated area should be 35 cubic yards. d) Install provisions for draining the area to prevent standing water problems. e) Keep the area clear of debris. f) Weep holes may be drilled into the side of the inlet. g) Protect weep holes with wire mesh and washed aggregate. h) Weep holes must be sealed when removing and stabilizing excavated area. i) A temporary dike may be necessary on the down slope side of the structure to prevent bypass flow. Maintenance Standards 1. Any accumulated sediment on or around inlet protection shall be removed immediately. Sediment shall not be removed with water, and all sediment must be disposed of as fill on site or hauled off site. 2. Any sediment in the catch basin insert shall be removed when the sediment has filled one-third of the available storage. The filter media for the insert shall be cleaned or replaced at least monthly. 3. Regular maintenance is critical for all forms of catch basin/inlet protection. Unlike many forms of protection that fail gradually, catch basin protection will fail suddenly and completely if not maintained properly. FIGURE D.2.1.5.E FILTER FABRIC PROTECTION CATCH BASIN NOTE: ONLY TO BE USED WHERE PONDING OF WATER ABOVE THE CATCH BASIN WILL NOT CAUSE TRAFFIC PROBLEMS AND WHERE OVERFLOW WILL NOT RESULT IN EROSION OF SLOPES. GRATE STANDARD STRENGTH FILTER FABRIC D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-55 FIGURE D.2.1.5.F CATCH BASIN INSERT NOTE: THIS DETAIL IS ONLY SCHEMATIC. ANY INSERT IS ALLOWED THAT HAS: •A MIN. 0.5 C.F. OF STORAGE, •THE MEANS TO DEWATER THE STORED SEDIMENT, •AN OVERFLOW, AND •CAN BE EASILY MAINTAINED. OVERFLOW GRATECATCH BASIN POROUS BOTTOM SOLID WALLS FILTER MEDIA FOR DEWATERING D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-67 c) Discharge to the sanitary sewer discharge with approval from King County and the City of Renton if there is no other option, or d) Use of a sedimentation bag with outfall to a ditch or swale for small volumes of localized dewatering. 2. Clean, non-turbid dewatering water, such as well-point ground water, may be discharged via stable conveyance to systems tributary to surface waters, provided the dewatering flow does not cause erosion or flooding of receiving waters. 3. Highly turbid or contaminated dewatering water (high pH or other) shall be handled separately from stormwater. See Section D.2.2 , SWPPS Measures. D.2.1.8 DUST CONTROL Preventative measures to minimize the wind transport of soil shall be taken when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources or adjacent properties. Purpose: To prevent wind transport of dust from exposed soil surfaces onto roadways, drainage ways, and surface waters. When to Install: Dust control shall be implemented when exposed soils are dry to the point that wind transport is possible and roadways, drainage ways, or surface waters are likely to be impacted. Dust control measures may consist of chemical, structural, or mechanical methods. Measures to Install: Water is the most common dust control (or palliative) used in the area. When using water for dust control, the exposed soils shall be sprayed until wet, but runoff shall not be generated by spraying. Calcium chloride, Magnesium chloride, Lignin derivatives, Tree Resin Emulsions, and Synthetic Polymer Emulsions may also be used for dust control. Exposed areas shall be re-sprayed as needed. Oil shall not be used for dust control. The following table lists many common dust control measures. Some of the measures are not recommended for use in the City and must have prior approval prior to use from the CED inspector assigned to specific projects. TABLE D.2.1.8.A DUST CONTROL MEASURES Method Considerations Site Preparation Recommended Application Rate Water -Most commonly used practice -Evaporates quickly -Lasts less than 1 day For all liquid agents: -Blade a small surface -Crown or slope surface to avoid ponding -Compact soils if needed -Uniformly pre-wet at 0.03 – 0.3 gal/sq yd -Apply solution under pressure. Overlap solution 6 – 12 inches -Allow treated area to cure 0 – 4 hours -Compact area after curing -Apply second treatment before first treatment becomes ineffective 0.125 gal/sq yd every 20 to 30 minutes Salts Calcium Chloride (CaCl) -Restricts evaporation -Lasts 6–12 months -Can be corrosive -Less effective in low humidity -Can build up in soils and leach by rain Apply 38% solution at 1.21L/m2 (0.27 gal/yd2) or as loose dry granules per manufacturer SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-68 TABLE D.2.1.8.A DUST CONTROL MEASURES Method Considerations Site Preparation Recommended Application Rate Magnesium Chloride (MgCl) -Restricts evaporation -Works at higher temperatures and lower humidity than CaCl -May be more costly than CaCl Apply 26 – 32% solution at 2.3 L/m2 (0.5 gal/yd2) Sodium Chloride (NaCl) -Effective over smaller range of conditions -Less expensive -Can be corrosive -Less effective in low humidity Per Manufacturer Silicates -Generally expensive -Available in small quantities -Require Second application Surfactants -High evaporation rates -Effective for short time periods -Must apply frequently Copolymers -Forms semi-permeable transparent crust -Resists ultraviolet radiation and moisture induced breakdown -Last 1 to 2 years 750 – 940 L/ha (80 – 100 gal/ac) Petroleum Products -Used oil is prohibited as a dust control method -Bind soil particles -May hinder foliage growth -Environmental and aesthetic concerns -Higher cost Use 57 – 63% resins as base. Apply at 750 – 940 L/ha (80–100 gal/ac) Lignin Sulfonate -Paper industry waste product -Acts as dispersing agent -Best in dry climates -Can be slippery -Will decrease Dissolved Oxygen in waterways therefore cannot be used adjacent to surface water systems Loosen surface 25–50 mm (1–2 inches) Need 4–8% fines Vegetable Oils -Coat grains of soils, so limited binding ability -May become brittle -Limited availability Per Manufacturer Spray on Adhesives -Available as organic or synthetic -Effective on dry, hard soils -Forms a crust -Can last 3 to 4 years Per Manufacturer D.2.1.9 FLOW CONTROL Surface water from disturbed areas must be routed through the project’s onsite flow control facility or other provisions must made to prevent increases in the existing site conditions 2-year and 10-year runoff peaks discharging from the project site during construction. Purpose: The purpose of surface water flow control is to mitigate increases in runoff peaks that occur during construction as a result of clearing vegetation, compacting the soil, and adding impervious surface. Such increases can cause or aggravate downstream flooding and erosion. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-69 When to Install: Surface water flow control shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct the surface water flow control facilities. Measures to Use: The project’s onsite flow control facility or other equivalent storage facility that meets the peak-matching performance criteria stated above. D.2.1.10 PROTECT EXISTING AND PROPOSED STORMWATER FACILITIES AND ON-SITE BMPS Protection measures shall be applied/installed and maintained so as to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed stormwater facilities and on-site BMPs for the project. Adverse impacts can prompt the requirement to restore or replace affected stormwater facilities and on-site BMPs. Purpose: The purpose of protecting existing and proposed stormwater facility and on-site BMP areas is to avoid sedimentation and soil compaction that would adversely affect infiltration, and also avoid contamination by other pollutants. When to Install: Stormwater facility and on-site BMP area protection shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct stormwater facilities and on-site BMPs. Measures to Use: 1. Protect all stormwater facilities and on-site BMPs and proposed stormwater facility and on-site BMP footprints from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the BMPs/facilities. 2. Stormwater facilities and on-site BMPs shall be restored to their fully functioning condition if they accumulate sediment during construction. Restoring the stormwater facilities and on-site BMPs shall include, at a minimum, removal of sediment and any sediment-laden bioretention soils, and replacing the removed soils with soils meeting the design specification. Replacement with a new fully- functioning stormwater facility and/or on-site BMP may be required if restoration to the fully- functioning condition can’t be accomplished. 3. Prevent compacting Bioretention BMPs/facilities by excluding construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. 4. Control erosion and avoid introducing sediment from surrounding land uses onto permeable pavement BMPs. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment-laden runoff onto permeable pavements. 5. Permeable pavement BMPs fouled with sediments or no longer passing an initial infiltration text must be cleaned using procedures from Appendix A or the manufacturer’s procedures. 6. Keep all heavy equipment off existing soils under stormwater facilities and on-site BMPs that have been excavated to final grade to retain the infiltration rate of the soils. D.2.1.11 MAINTAIN PROTECTIVE BMPS Protection measures shall be maintained to ensure continued performance of their intended function, to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed BMPs/facilities, and protect other disturbed areas of the project. Purpose: The purpose of maintaining protective BMPs is to provide continuous erosion and sediment control protection throughout the life of the project, and avoid sedimentation, soil compaction and contamination by other pollutants that would adversely affect infiltration and surface runoff. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-70 When to Maintain: Protection measures shall be monitored per Section D.2.4.4 at a minimum, and promptly maintained to fully functioning condition as necessary to ensure continued performance of their intended function. Measures to Use: 1. Maintain and repair all temporary and permanent erosion and sediment control BMPs as needed to ensure continued performance of their intended function in accordance with BMP specifications. 2. Remove all temporary erosion and sediment control BMPs prior to final construction approval, or within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. 3. Provide protection to all stormwater facilities and on-site BMPs installed for the permanent control of stormwater from sediment and compaction. All stormwater facilities and on-site BMPs that are to remain in place following completion of construction shall be examined and placed in full operating conditions. If sediment enters the stormwater facilities and/or on-site BMPs during construction, it shall be removed and the stormwater facility and on-site BMP shall be returned to the conditions specified in the construction documents or as required for full stormwater facility and on-site BMP replacement. 4. Remove or stabilize trapped sediment on site. Permanently stabilize disturbed soil resulting from removal of erosion and sediment control BMPs or vegetation. D.2.1.12 MANAGE THE PROJECT Coordination and timing of site development activities relative to ESC concerns (Section D.2.4), and timely inspection, maintenance and update of protective measures (Section D.2.3) are necessary to effectively manage the project and ensure the success of protective ESC and SWPPS design and implementation. Projects shall assign a qualified CSWPP Supervisor (Section D.2.3.1) to be the primary contact for ESC and SWPPP issues and reporting, coordination with subcontractors and implementation of the CSWPP plan as a whole. Measures to Use: 1. Phase development projects to the maximum degree practicable and take into account seasonal work limits. 2. Inspection and monitoring – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Conduct site inspections and monitoring in accordance with the Construction Stormwater General Permit and City requirements. 3. Maintaining an updated construction SWPPP – Maintain, update, and implement the SWPPP in accordance with the Construction Stormwater General Permit and City requirements. 4. Projects that disturb one or more acres must have, site inspections conducted by a Certified Erosion and Sediment Control Lead (CESCL) (see Section D.2.3.1). Project sites less than one acre (not part of a larger common plan of development or sale) may have a person without CESCL certification conduct inspections. By the initiation of construction, the SWPPP must identify the CESCL or inspector, who shall be present onsite or on-call at all times. The CESCL or inspector (project sites less than one acre) must have the skills to assess the: • Site conditions and construction activities that could impact the quality of stormwater. • Effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. • The CESCL or inspector must examine stormwater visually for the presence of suspended sediment, turbidity, discoloration, and oil sheen. They must evaluate the effectiveness of BMPs and determine if it is necessary to install, maintain, or repair BMPs to improve the quality of stormwater discharges. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-71 Based on the results of the inspection, construction site operators must correct the problems identified by: • Reviewing the SWPPP for compliance with all construction SWPPP elements and making appropriate revisions within 7 days of the inspection. • Immediately beginning the process of fully implementing and maintaining appropriate source control and/or treatment BMPs as soon as possible, addressing the problems not later than within 10 days of the inspection. If installation of necessary treatment BMPs is not feasible within 10 days, the construction site operator may request an extension within the initial 10-day response period. • Documenting BMP implementation and maintenance in the site log book (applies only to sites that have coverage under the Construction Stormwater General Permit). • The CESCL or inspector must inspect all areas disturbed by construction activities, all BMPs, and all stormwater discharge points at least once every calendar week and within 24 hours of any discharge from the site. (For purposes of this condition, individual discharge events that last more than one day do not require daily inspections. For example, if a stormwater pond discharges continuously over the course of a week, only one inspection is required that week.) The CESCL or inspector may reduce the inspection frequency for temporary stabilized, inactive sites to once every calendar month. D.2.2 SWPPS MEASURES This section details the SWPPS measures that are required to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses from construction-related activities such as materials delivery and storage, onsite equipment fueling and maintenance, demolition of existing buildings and disposition of demolition materials and other waste, and concrete handling, washout and disposal. These SWPPS measures represent Best Management Practices (BMPs)8 for the control of pollutant drips and spills as well as other impacts related to construction such as increased pH in concrete construction and handling activities. Compliance with each of the SWPPS measures, and with any project- specific control measures, to the extent applicable and necessary to meet the performance criteria in Section D.2.2, and compliance with the CSWPP implementation requirements in Section D.2.4, constitutes overall compliance with the City’s CSWPP Standards. Note: Additional measures shall be required by the City if the existing standards are insufficient to protect adjacent properties, drainage facilities, or water resources. The standards for each individual SWPPS measure are divided into four sections: 1. Purpose 2. Conditions of Use 3. Design and Installation Specifications 4. Maintenance Requirements. Note that the “Conditions of Use” always refers to site conditions. As site conditions change, SWPPS measures must be changed to remain in compliance with the requirements of this appendix. Whenever compliance with City SWPPS Standards is required, all of the following SWPPS measures must be considered for application to the project site as detailed in the following sections. The construction pollutant generating concerns addressed by the BMPs that follow include: • Concrete handling, washout and disposal(specifically portland cement concrete) • Sawcutting and surfacing activities • Materials delivery, storage and containment 8 Best Management Practices (BMPs) means the best available and reasonable physical, structural, managerial, or behavioral activities, that when singly or in combination, eliminate or reduce the contamination of surface and/or ground waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-72 • Filtration and chemical treatment of construction water to facilitate disposal or discharge to approved locations • Reporting requirements and documentation availability for specific BMP processes Additionally, several of the ESC BMPs described in Section D.2.1 can be applicable to the SWPPS plan, e.g., use of cover, fencing and access protection to protect temporary materials storage locations. The applicant’s material supplier may be a resource (subject to City approval) for BMPs to address specific project applications or proposals. Conditions of approval on adjustments may also specify additional requirements for the SWPPS plan. D.2.2.1 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, curbs, sidewalks, roads, bridges, foundations, floors, stormwater vaults, retaining walls, driveways and runways. Design and Installation Specifications 1. Ensure 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 D.2.2.2 for information on concrete washout areas. 2. 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. 3. Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas only. 4. Wash equipment difficult to move, such as concrete pavers in areas that do not directly drain to natural or constructed stormwater conveyances. 5. Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. 6. 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. 7. Always use forms or solid barriers for concrete pours, such as pilings, within 15-feet of surface waters. 8. Refer to BMPs D.2.2.7 and D.2.2.8 for pH adjustment requirements. 9. Refer to the Construction Stormwater General Permit for pH monitoring requirements if the project involves one of the following activities: • Significant concrete work (greater than 1,000 cubic yards poured concrete or recycled concrete used over the life of a project). • The use of engineered soils amended with (but not limited to) Portland cement-treated base, cement kiln dust or fly ash. • 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. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-73 D.2.2.2 CONCRETE WASHOUT AREA Purpose Prevent or reduce the discharge of pollutants to stormwater from concrete waste by conducting washout off-site, or performing onsite 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 onsite. Note: If less than 10 concrete trucks or pumpers need to be washed out onsite, the washwater may be disposed of in a formed area awaiting concrete or an upland disposal site where it will not contaminate surface or ground water. The upland disposal site shall be at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. Design and Installation Specifications Implementation The following steps will help reduce stormwater pollution from concrete wastes: 1. Perform washout of concrete trucks at an approved off-site location or in designated concrete washout areas only. 2. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. 3. Do not allow excess concrete to be dumped onsite, except in designated concrete washout areas. 4. Concrete washout areas may be prefabricated concrete washout containers, or self-installed structures (above-grade or below-grade). 5. 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. 6. 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. 7. Self-installed above-grade structures should only be used if excavation is not practical. Education 1. Discuss the concrete management techniques described in this BMP with the ready-mix concrete supplier before any deliveries are made. 2. Educate employees and subcontractors on the concrete waste management techniques described in this BMP. 3. Arrange for contractor’s superintendent or Certified Erosion and Sediment Control Lead (CESCL) to oversee and enforce concrete waste management procedures. 4. 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. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-74 Location and Placement 1. Locate washout area at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. 2. Allow convenient access for concrete trucks, preferably near the area where the concrete is being poured. 3. If trucks need to leave a paved area to access washout, prevent track-out with a pad of rock or quarry spalls (see BMP D.2.1.4.2). These areas should be far enough away from other construction traffic to reduce the likelihood of accidental damage and spills. 4. The number of facilities you install should depend on the expected demand for storage capacity. 5. 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: 1. 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 Figures D.2.2.2.A, D.2.2.2.B, and D.2.2.2.C). 2. Concrete washout facilities shall be constructed and maintained in sufficient quantity and size to contain all liquid and concrete waste generated by washout operations. 3. Washout of concrete trucks shall be performed in designated areas only. 4. 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. 5. 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. 6. Temporary Above-Grade Concrete Washout Facility a) 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 ft, but with sufficient quantity and volume to contain all liquid and concrete waste generated by washout operations. b) 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. 7. Temporary Below-Grade Concrete Washout Facility a) 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. b) Lath and flagging should be commercial type. c) 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. d) Liner seams shall be installed in accordance with manufacturers’ recommendations. e) Soil base shall be prepared free of rocks or other debris that may cause tears or holes in the plastic lining material. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-75 Maintenance Standards Inspection and Maintenance 1. Inspect and verify that concrete washout BMPs are in place prior to the commencement of concrete work. 2. During periods of concrete work, inspect daily to verify continued performance. a) Check overall condition and performance. b) Check remaining capacity (% full). c) If using self-installed washout facilities, verify plastic liners are intact and sidewalls are not damaged. d) If using prefabricated containers, check for leaks. 3. Washout facilities shall be maintained to provide adequate holding capacity with a minimum freeboard of 12 inches. 4. Washout facilities must be cleaned, or new facilities must be constructed and ready for use once the washout is 75% full. 5. If the washout is nearing capacity, vacuum and dispose of the waste material in an approved manner. a) Do not discharge liquid or slurry to waterways, storm drains or directly onto ground. b) Do not use sanitary sewer without local approval. c) 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. d) Remove and dispose of hardened concrete and return the structure to a functional condition. Concrete may be reused onsite or hauled away for disposal or recycling. 6. 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 1. 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. 2. Materials used to construct temporary concrete washout facilities shall be removed from the site of the work and disposed of or recycled. 3. 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. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-76 FIGURE D.2.2.2.A CONCRETE WASHOUT AREA (ABOVE GRADE) SECTION B-B NTS SECTION A-A NTS STAPLE DETAIL NTS PLAN NTS ABOVE GRADE TEMPORARY CONCRETE WASHOUT FACILITY NTS CONCRETE WASHOUT SIGN DETAIL NTS 10 mil PLASTIC LINING PLAN NTS TYPE "ABOVE GRADE" WITH WOOD PLANKS TYPE "ABOVE GRADE" WITH STRAW BALES 10 mil PLASTIC LINING 16 GAUGE STEEL WIRE 2" 8" LAG SCREWS ( 12" ) BLACK LETTERS 6" HEIGHT PLYWOOD 4' X 2' PAINTED WHITE WOOD POST 312" x 312" x 8'3' 3' STRAW BALES (TYP.) STAKE (TYP.) WEDGE LOOSE STRAW BETWEEN BALES SAND OR GRAVEL-FILLED BAGS IN CORNERS 10' MIN. RECOMMENDED VARIES WOOD OR METAL STAKES (2 PER BALE) STRAW BALES (2 BALES HIGH, MAX.) ORIGINAL GROUND 10 mil PLASTIC LINING STAPLES (2 PER BALE) SAND OR GRAVEL-FILLED BAGS IN CORNERS NATIVE MATERIAL (OPTIONAL) 10 mil PLASTIC LINING WOOD FRAME SECURELY FASTENED AROUND ENTIRE PERIMETER WITH TWO STAKES TWO-STACKED 2x12 ROUGH WOOD FRAME STAKE (TYP.) 10' MIN. RECOMMENDED VARIES NOTES: 1.ACTUAL LAYOUT DETERMINED IN THE FIELD 2.THE CONCRETE WASHOUT SIGN SHALL BE INSTALLED WITHIN 30' OF THE FACILITY 1' MIN. Adapted from CalTrans Fig4-14 SAC 8-14-02 D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-77 FIGURE D.2.2.2.B CONCRETE WASHOUT AREA (BELOW GRADE) FIGURE D.2.2.2.C PREFABRICATED CONCRETE WASHOUT CONTAINER W/RAMP EARTHEN BERM TYPICAL SECTION NTS BELOW GRADE TEMPORARY CONCRETE WASHOUT FACILITY NTS CONCRETE WASHOUT SIGN DETAIL NTS SANDBAG PLAN NTS Adapted from CalTrans Fig4-14 SAC 8-14-02 10 mil PLASTIC LINING LAG SCREWS ( 12" ) BLACK LETTERS 6" HEIGHT PLYWOOD 4' X 2' PAINTED WHITE WOOD POST 312" x 312" x 8'3' 3' EARTHEN BERM 10 mil PLASTIC LINING SANDBAG 10' MIN. RECOMMENDED VARIES BERM 3' LATH AND FLAGGING ON 3 SIDES NOTES: 1.ACTUAL LAYOUT DETERMINED IN THE FIELD 2.THE CONCRETE WASHOUT SIGN SHALL BE INSTALLED WITHIN 30' OF THE FACILITY SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-78 D.2.2.3 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, sawing, coring, grinding, roughening, hydro- demolition, bridge and road surfacing Design and Installation Specifications 1. Vacuum slurry and cuttings during cutting and surfacing operations. 2. Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight. 3. Slurry and cuttings shall not drain to any natural or constructed drainage conveyance including stormwater systems. This may require temporarily blocking catch basins. 4. Dispose of collected slurry and cuttings in a manner that does not violate ground water or surface water quality standards. 5. 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. 6. Handle and dispose cleaning waste material and demolition debris in a manner that does not cause contamination of water. Dispose of sweeping material from a pick-up sweeper at an appropriate disposal site. Maintenance Standards Continually monitor operations to determine whether slurry, cuttings, or process water could enter waters of the state. If inspections show that a violation of water quality standards could occur, stop operations and immediately implement preventive measures such as berms, barriers, secondary containment, and vacuum trucks. D.2.2.4 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 onsite, 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 D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-79 • Hazardous chemicals such as acids, lime, adhesives, paints, solvents and curing compounds • Any other material that may be detrimental if released to the environment Design and Installation Specifications The following steps should be taken to minimize risk: 1. Temporary storage area should be located away from vehicular traffic, near the construction entrance(s), and away from waterways or storm drains. 2. Material Safety Data Sheets (MSDS) should be supplied for all materials stored. Chemicals should be kept in their original labeled containers. 3. Hazardous material storage onsite should be minimized. 4. Hazardous materials should be handled as infrequently as possible. 5. During the wet weather season (October 1 – April 30), consider storing materials in a covered area. 6. 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. 7. 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. 8. 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: 1. 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. 2. 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. 3. Secondary containment facilities shall be impervious to the materials stored therein for a minimum contact time of 72 hours. 4. 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. 5. Sufficient separation should be provided between stored containers to allow for spill cleanup and emergency response access. 6. During the wet weather season (October 1 – April 30), each secondary containment facility shall be covered during non-working days, prior to and during rain events. 7. Keep material storage areas clean, organized and equipped with an ample supply of appropriate spill clean-up material (spill kit). 8. The spill kit should include, at a minimum: • 1-Water Resistant Nylon Bag • 3-Oil Absorbent Socks 3″ x 4′ • 2-Oil Absorbent Socks 3″ x 10′ • 12-Oil Absorbent Pads 17″ x 19″ SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-100 proper disposal must be submitted to the City. All authorizations for disposal shall be obtained prior to CKD/CTB application. • Infiltration: Depending on the site conditions, pH-adjusted stormwater may be infiltrated. Prior to infiltration, pH must be between 6.5 and 8.5. • Surface Water: Contact water from the application area shall not be discharged to surface waters, even if treatment has adjusted the pH. 8. Emergency backup plan: An emergency backup plan must be prepared and ready to implement to handle large quantities of stormwater. 9. Monitoring shall be conducted to determine that contact stormwater is not leaving the site. Offsite monitoring shall also be conducted to identify impacts to adjacent water bodies. Bonding may be required to cover mitigation of impacts and restoration. 10. A soils specialist will establish the mixing percentage for onsite soils. Soil amendments will never occur in excess of the ability of the onsite equipment and resources to meet all BMP requirements. 11. For sites one acre or larger, a Construction Stormwater General permit must be obtained from Ecology. Construction Stormwater General permits and ‘Stormwater Pollution Prevention Plans (SWPPPs) must be amended and the use of CKD/CTB must be approved by Ecology prior to application. The contractor/developer shall comply will all federal, state, and local regulations. A health and safety plan may be required for the protection of CED inspectors. Additional BMPs may be applicable depending on mix design, proximity of wetlands or streams (e.g., within 300 feet of class/type I and 100 feet or less for other types) and site conditions. D.2.2.10 MAINTAIN PROTECTIVE BMPS Pollutant protection measures shall be maintained to ensure continued performance of their intended function. Reporting and documentation shall be kept current and made available to CED as indicated. Purpose: The purpose of maintaining protective BMPs is to provide effective pollutant protection when and where required by the plan and the project, and to provide timely and relevant project information. When to Maintain: Protection measures shall be monitored per Section D.2.4.4 at a minimum, continuously during operation, and promptly maintained to fully functioning condition as necessary to ensure continued performance of their intended function. Documentation shall be kept current per specific BMP requirements. Measures to Use: 1. Maintain and repair all pollutant control BMPs as needed to ensure continued performance of their intended function in accordance with BMP specifications. 2. Maintain and repair storage locations for equipment and materials associated with BMP processes. Conduct materials disposal in compliance with City requirements. 3. As required, provide current reporting and performance documentation at an accessible location for the site inspector and other CED staff. 4. Remove all temporary pollutant control BMPs prior to final construction approval, or within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. D.2.2.11 MANAGE THE PROJECT SWPPP requirements shall be implemented and managed as part of the overall CSWPP plan. Concrete construction and its impacts are primary among pollutant concerns on site development projects. Fueling operations and materials containment of treatment chemicals and other project materials are also typical D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-101 pollutant concerns. Operations that produce these and other pollutants are often conducted by subcontractors and their laborers, yet may require specific protective measures, documentation and reporting. Protective measures and BMPs need to be made available prior to construction and suitable oversight provided to ensure inspection, monitoring and documentation requirements are met. Projects shall assign a qualified CSWPP Supervisor (Section D.2.3.1) to be the primary contact for SWPPP and ESC issues and reporting, coordination with subcontractors and implementation of the CSWPP plan as a whole. Measures to Use: 1. Phase development projects to the maximum degree practicable and take into account seasonal work limits. 2. Inspection and monitoring – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Conduct site inspections and monitoring in accordance with the Construction Stormwater General Permit and City requirements. Coordinate with subcontractors and laborers to ensure the SWPPP measures are followed. 3. Documentation and reporting – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Document site inspections and monitoring in accordance with the Construction Stormwater General Permit, specific BMP conditions and City requirements. Log sheets provided in Reference Section 8 may be used if appropriate. Follow reporting requirements and provide documentation as requested to CED staff. 4. Maintaining an updated construction SWPPP – Maintain, update, and implement the SWPPP in accordance with the Construction Stormwater General Permit and City requirements. Obtain approval for specific SWPPP measures (e.g., chemical treatments of stormwater) well in advance of need. Coordinate SWPPP plan updates with the site inspector (see Section D.2.4.1). D.2.3 CSWPP PERFORMANCE AND COMPLIANCE PROVISIONS The changing conditions typical of construction sites call for frequent field adjustments of existing ESC and SWPPS measures or additional ESC and SWPPS measures in order to meet required performance. In some cases, strict adherence to specified measures may not be necessary or practicable based on site conditions or project type. In other cases, immediate action may be needed to avoid severe impacts. Therefore, careful attention must be paid to ESC and SWPPS performance and compliance in accordance with the provisions contained in this section. D.2.3.1 CSWPP SUPERVISOR For projects in Targeted, Full, or Large Project Drainage Review, or projects in Directed Drainage Review as determined by CED review staff, the applicant must designate a CSWPP supervisor who shall be responsible for the performance, maintenance, and review of ESC and SWPPS measures and for compliance with all permit conditions relating to CSWPP as described in the CSWPP Standards. The applicant’s selection of a CSWPP supervisor must be approved by the City. (City approval may be rescinded for non-compliance, requiring the applicant to select another CSWPP supervisor and obtain City approval prior to continuing work on the project site.) For projects that disturb one acre or more of land, the CSWPP supervisor must be a Certified Professional in Erosion and Sediment Control (see <www.cpesc.net> for more information) or a Certified Erosion and Sediment Control Lead whose certification is recognized by the City.11 The City may also require a certified ESC professional for sites smaller than one acre of disturbance if CED determines that onsite ESC measures are inadequately installed, located, or maintained. 11 The City’s recognition of certification means that the individual has taken an approved third party training program and has passed the approved test for that training program. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-102 For larger, more sensitive sites, the City may require a certified ESC professional with several years of experience in construction supervision/inspection and a background in geology, soil science, or agronomy. Typically, if a geotechnical consultant is already working on the project, the consultant may also be a certified ESC professional designated as the CSWPP supervisor. The design engineer may also be qualified for this position. This requirement shall only be used for sensitive sites that pose an unusually high risk of impact to surface waters as determined by CED. At a minimum, the project site must meet all of the following conditions in order to require the applicant to designate as the CSWPP supervisor a certified ESC professional with such expertise: • Alderwood soils or other soils of Hydrologic Group C or D • Five acres of disturbance • Large areas (i.e., two or more acres) with slopes in excess of 10 percent. Proximity to streams or wetlands or phosphorus-sensitive lakes, such as Lake Sammamish, shall also be a factor in determining if such expertise in the CSWPP supervisor is warranted. However, proximity alone shall not be a determining factor because even projects that are a considerable distance from surface waters can result in significant impacts if there is a natural or constructed drainage system with direct connections to surface waters. The name, address, and phone number of the CSWPP supervisor shall be supplied to the City prior to the start of construction. A sign shall be posted at all primary entrances to the site identifying the CSWPP supervisor and his/her phone number. The requirement for a CSWPP supervisor does not relieve the applicant of ultimate responsibility for the project and compliance with Renton Municipal Code. D.2.3.2 MONITORING OF DISCHARGES The CSWPP supervisor shall have a turbidity meter onsite and shall use it to monitor surface and storm water discharges from the project site and into onsite wetlands, streams, or lakes whenever runoff occurs from onsite activities and during storm events. The CSWPP supervisor shall keep a log of all turbidity measurements taken onsite and make it available to CED upon request. If the project site is subject to a NPDES general permit for construction issued by the Washington State Department of Ecology (Ecology), then the project must comply with the monitoring requirements of that permit. The CSWPP supervisor shall also use the specific SWPPS BMP procedures for monitoring surface and stormwater discharge for pollutants and acceptable discharge levels. The CSWPP supervisor shall keep logs as required by the procedures of all measurements taken onsite and make them available to CED on request. D.2.3.3 ESC PERFORMANCE ESC measures shall be applied/installed and maintained so as to prevent, to the maximum extent practicable, the transport of sediment from the project site to downstream drainage systems or surface waters or into onsite wetlands, streams, or lakes or onto adjacent properties. This performance is intended to be achieved through proper selection, installation, and operation of the above ESC measures as detailed in the CSWPP Standards (Appendix D) and approved by the City. However, the CSWPP supervisor designated per Section D.2.3.1 or the City may determine at any time during construction that such approved measures are not sufficient and additional action is required based on one of the following criteria: 1. IF a turbidity test of surface and storm water discharges leaving the project site is greater than the benchmark value of 25 nephelometric turbidity units (NTU) set by the Washington State Department of Ecology, but less than 250 NTU, the CSWPP Supervisor shall do all of the following: a) Review the ESC plan for compliance and make appropriate revisions within 7 days of the discharge that exceeded the benchmark of 25 NTU, AND D.2.3 CSWPP PERFORMANCE AND COMPLIANCE PROVISIONS 2017 City of Renton Surface Water Design Manual 12/12/2016 D-103 b) Fully implement and maintain appropriate ESC measures as soon as possible but no later than 10 days after the discharge that exceeded the benchmark, AND c) Document ESC implementation and maintenance in the site log book. 2. IF a turbidity test of surface or storm water entering onsite wetlands, streams, or lakes indicates a turbidity level greater than 5 NTU above background when the background turbidity is 50 NTU or less, or 10% above background when the background turbidity is greater than 50 NTU, then corrective actions and/or additional measures beyond those specified in SWDM Section 1.2.5.1 shall be implemented as deemed necessary by the CED inspector or onsite CSWPP supervisor. 3. IF discharge turbidity is 250 NTU or greater, the CSWPP Supervisor shall do all of the following: a) Notify the City by telephone, AND b) Review the ESC plan for compliance and make appropriate revisions within 7 days of the discharge that exceeded the benchmark of 25 NTU, AND c) Fully implement and maintain appropriate ESC measures as soon as possible but no later than 10 days after the discharge that exceeded the benchmark, AND d) Document ESC implementation and maintenance in the site log book. AND e) Continue to sample discharges until turbidity is 25 NTU or lower, or the turbidity is no more than 10% over background turbidity. 4. IF the City determines that the condition of the construction site poses a hazard to adjacent property or may adversely impact drainage facilities or water resources, THEN additional measures beyond those specified in SWDM Section 1.2.5.1 may be required by the City. D.2.3.4 SWPPS PERFORMANCE SWPPS measures shall be applied/installed and maintained so as to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses or onto adjacent properties. This performance is intended to be achieved through proper selection, installation, and operation of the above SWPPS measures as detailed in the CSWPP Standards (Appendix D) and approved by the City. However, the CSWPP supervisor designated per Section D.2.3.1 or the City may determine at any time during construction that such approved measures are not sufficient and additional action is required based on the criteria described in the specific SWPPS BMP standard and/or conditions of an approved adjustment. D.2.3.5 FLEXIBLE COMPLIANCE Some projects may meet the intent of Core Requirement #5 while varying from specific CSWPP requirements in this appendix. If a project is designed and constructed such that it meets the intent of the core requirement, the City may determine that strict adherence to a specific ESC requirement is unnecessary; an approved adjustment (see Section 1.4) from the SWDM is not required in these circumstances. Certain types of projects are particularly likely to warrant this greater level of flexibility; for instance, projects on relatively flat, well drained soils, projects that are constructed in closed depressions, or projects that only disturb a small percentage of a forested site may meet the intent of this requirement with very few ESC measures. Note, however, that SWPPS requirements may actually be emphasized on well-drained soils, particularly in groundwater protection or well-protection areas, or in close proximity to water bodies. D.2.3.6 ROADS AND UTILITIES COMPLIANCE Road and utility projects often pose difficult erosion control challenges because they frequently cross surface waters and because narrow right-of-way constrains areas available to store and treat sediment- laden water. In most cases, the standards of this appendix may be applied to such linear projects without SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-104 modification. For instance, the ability to use perimeter control rather than a sediment retention facility for small drainage areas (see Section D.2.1.3) will apply to many of these projects. However, there may be some projects that cannot reasonably meet the standards of Core Requirement #5 and this appendix. In these cases, other measures may be proposed that will provide reasonable protection. An adjustment is not required for such projects, unless the City determines that measures proposed by the applicant fail to meet the intent of Core Requirement #5 and this appendix, and that significant adverse impacts to surface water may result. Examples of other measures that may be taken in lieu of the standards of this appendix are: 1. Phasing the project so that the site is worked progressively from end to end, rather than clearing and grubbing the entire length of the project. This results in smaller exposed areas for shorter durations, thus reducing the erosion risk. It is recommended that there be no more than 500 feet of open trench during any phase of construction. 2. Placement of excavated materials from utility trenches on the upslope side of the excavation, to minimize transport of sediment outside of the project area. 3. Mulching and vegetating cut and fill slopes as soon as they are graded. Frequently, this is done at the end of construction when paving or utility installation is complete. Vegetating these areas at the start of the project stabilizes those areas most susceptible to erosion. 4. Protecting all catch basin inlets with catch basin inserts or other inlet protection when these do not drain to ponds or traps. This will not provide the same level of protection as a sediment pond or trap, but can remove most of the sand-sized material entrained in the runoff. 5. Phasing the project so that all clearing and grading in critical area buffers occurs in the dry season. This substantially reduces the chance of erosion and allows for rapid revegetation in the late summer and early fall. 6. Using approved flocculent or other chemical treatment approved by the City to reduce the turbidity of water released from sediment ponds. 7. Hiring a private consultant with expertise in ESC to review and monitor the site. 8. Limiting employee/contractor parking and overnight/weekend parking of construction vehicles to dedicated and controlled areas prepared for drip and spill control. Options in the right-of-way for such areas can be limited. If alternatives are used, it may be appropriate to develop a monitoring program that would monitor compliance with the performance standard of Core Requirement #5 and/or impacts to nearby water resources. Of particular concern are impacts to salmonid spawning gravels. McNeil sampling is a possible method of sampling to determine impacts to spawning gravels (see Section D.2.4.3). D.2.3.7 ALTERNATIVE MEASURES In general, the SWDM only contains those BMPs that are standards of the local industry. There are a variety of other BMPs available that may also be used, even though they are not included in this appendix. Such alternatives may be approved without an adjustment if the alternative will produce a compensating or comparable result with the measures in this appendix. Variations on or modifications of the BMPs in this appendix may also be granted based on the same criteria. An adjustment may be required for products or techniques that are new and untested (see Section 1.4.4 of the SWDM). In addition, the new product or technique must be approved through the state Department of Ecology’s CTAPE program.12 The intent of this requirement is not to discourage new techniques, but to 12 CTAPE stands for Chemical Technology Assessment Protocol – Ecology. For more information, see Ecology’s website at <http://www.ecy.wa.gov/programs/wq/stormwater/newtech/tape_ctape.htm>. D.2.3 CSWPP PERFORMANCE AND COMPLIANCE PROVISIONS 2017 City of Renton Surface Water Design Manual 12/12/2016 D-105 ensure that new techniques are monitored and documented for adequacy and possible inclusion in subsequent versions of the SWDM. D.2.4 CSWPP IMPLEMENTATION REQUIREMENTS This section describes the CSWPP implementation requirements that are required at each construction site. The measures and practices correspond to the implementation requirements in Core Requirement #5. Three of the sections (the CSWPP report (Section D.2.4.1, below), CSWPP maintenance requirements (Section D.2.4.4), and final site stabilization (Section D.2.4.5) are required of every project. The rest of the sections are special requirements that may apply to the project depending on site conditions and project type. The introductory paragraphs at the beginning of most sections present the purpose of the measures and when they should be applied to the site. Compliance with the implementation requirements (as appropriate for the site) ensures compliance with the CSWPP measures. Note, however, that additional measures shall be required by the City if the existing standards are insufficient to protect adjacent properties, drainage facilities, or water resources. D.2.4.1 CSWPP PLAN A CSWPP plan, containing the ESC plan and the SWPPS plan, and showing the location and details of ESC and SWPPS measures, is required for all proposed projects. It shall include a CSWPP report, which includes supporting information for providing ESC and SWPPS measures and meeting CSWPP implementation requirements. A copy of the CSWPP plan with CSWPP report shall be kept at the project site throughout all phases of construction. All of the materials required for the CSWPP report are standard parts of engineering plan submittals for projects requiring drainage review. The simplest approach to preparing this report is to compile the pieces during preparation for submittal and include the report as a separate part of the CSWPP plan submittal package. The CSWPP report shall include the following: 1. A detailed construction sequence, as proposed by the design engineer or erosion control specialist, identifying required ESC measures and implementation requirements; 2. A technical information report (TIR) and ESC and SWPPS plans for CED review in accordance with Sections 2.3.1 and 2.3.3 of the SWDM. Incorporate any City review comments as necessary to comply with Core Requirement #5 of the SWDM (Section 1.2.5) and the Construction Stormwater Pollution Prevention Standards adopted in this appendix; 3. Any calculations or information necessary to size ESC measures and demonstrate compliance with Core Requirement #5; 4. Descriptions and any supporting documentation, operating procedures, precautions, logging and reporting requirements, etc., for the project’s SWPPS BMPs, 5. An inspection and maintenance program in accordance with Section D.2.4.4 that includes the designation of a certified CSWPP supervisor as point of contact; and 6. Anticipated changes or additions necessary during construction to ensure that ESC and SWPPS measures perform in accordance with Core Requirement #5 and Sections D.2.1 and D.2.2. While the CSWPP plan focuses on the initial measures to be applied to the site, any changes or additions necessary during construction to ensure that ESC and SWPPS measures perform in accordance with Core Requirement #5 and Sections D.2.1, D.2.2 and D.2.4 must be identified in the CSWPP report. The City may require large, complex projects to phase construction and submit multiple ESC plans for different stages of construction. Development of new CSWPP plans is not required for changes that are necessary during construction. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-106 D.2.4.2 WET SEASON REQUIREMENTS Any site with exposed soils during the wet season (October 1 to April 30) shall be subject to the special provisions below. In addition to the ESC cover measures (see Section D.2.1.2), these provisions include covering any newly seeded areas with mulch and identifying and seeding as much disturbed area as possible prior to September 23 in order to provide grass cover for the wet season. A “wet season ESC plan” must be submitted and approved by the City before work proceeds or continues. Wet Season Special Provisions All of the following provisions for wet season construction are detailed in the referenced sections. These requirements are listed here for the convenience of the designer and the reviewer. 1. The allowed time that a disturbed area may remain unworked without cover measures is reduced to two consecutive working days, rather than seven (Section D.2.1.2). 2. Stockpiles and steep cut and fill slopes are to be protected if unworked for more than 12 hours (Section D.2.1.2). 3. Cover materials sufficient to cover all disturbed areas shall be stockpiled on site (Section D.2.1.2). 4. All areas that are to be unworked during the wet season shall be seeded within one week of the beginning of the wet season (Section D.2.1.2.6). 5. Mulch is required to protect all seeded areas (Section D.2.1.2.2). 6. Fifty linear feet of silt fence (and the necessary stakes) per acre of disturbance must be stockpiled on site (Section D.2.1.3.1). 7. Construction road and parking lot stabilization are required for all sites unless the site is underlain by coarse-grained soil (Section D.2.1.4.2). 8. Sediment retention is required unless no offsite discharge is anticipated for the specified design flow (Section D.2.1.5). 9. Surface water controls are required unless no offsite discharge is anticipated for the specified design flow (Section D.2.1.6). 10. Phasing and more conservative BMPs must be evaluated for construction activity near surface waters (Section D.2.4.3). 11. Any runoff generated by dewatering may be required to discharge to the sanitary sewer (with appropriate discharge authorization), portable sand filter systems, or holding tanks (Section D.2.2). D.2.4.3 CRITICAL AREAS RESTRICTIONS Any construction that will result in disturbed areas on or within a stream or associated buffer, a wetland or associated buffer, or within 50 feet of a lake shall be subject to the special provisions below. These provisions include, whenever possible, phasing the project so that construction in these areas is limited to the dry season. The City may require more conservative BMPs, including more stringent cover requirements, in order to protect surface water quality. Any project proposing work within 50 feet of a steep slope hazard area shall evaluate the need for diverting runoff that might flow over the top of the slope. Critical Areas Special Provisions Any project that disturbs areas on or within a stream or associated buffer, wetland or associated buffer, or within 50 feet of a lake has the potential to seriously damage water resources, even if the project is relatively small. While it is difficult to require specific measures for such projects because the CSWPP plan must be very site specific, the following recommendations shall be incorporated into the plan where appropriate: D.2.4 CSWPP IMPLEMENTATION REQUIREMENTS 2017 City of Renton Surface Water Design Manual 12/12/2016 D-107 1. Whenever possible, phase all or part of the project so that it occurs during the dry season. If this is impossible, November through February shall be avoided since this is the most likely period for large, high-intensity storms. 2. All projects shall be completed and stabilized as quickly as possible. Limiting the size and duration of a project is probably the most effective form of erosion control. 3. Where appropriate, sandbags or an equivalent barrier shall be constructed between the project area and the surface water in order to isolate the construction area from high water that might result due to precipitation. 4. Additional perimeter protection shall be considered to reduce the likelihood of sediment entering the surface waters. Such protection might include multiple silt fences, silt fences with a higher AOS, construction of a berm, or a thick layer of organic mulch upslope of a silt fence. 5. If work is to occur within the ordinary high water mark of a stream, most projects must isolate the work area from the stream by diverting the stream or constructing a cofferdam. Certain small projects that propose only a small amount of grading may not require isolation since diversions typically result in disturbance and the release of some sediment to the stream. For such small projects, the potential impacts from construction with and without a diversion must be weighed. 6. If a stream must be crossed, a temporary bridge shall be considered rather than allowing equipment to utilize the streambed for a crossing. For projects in or near a salmonid stream, it may be appropriate to monitor the composition of any spawning gravels within a quarter-mile of the site with a McNeil sampler or similar method approved by the City before, during, and after construction. The purpose of such monitoring would be to determine if the fine content of the gravels increases as a result of construction impacts. Monitoring results could be used to guide erosion control efforts during construction and as a threshold for replacing spawning gravels if the fine content rises significantly. D.2.4.4 MAINTENANCE REQUIREMENTS All ESC and SWPPS measures shall be maintained and reviewed on a regular basis as prescribed in the maintenance requirements for each BMP and in this section. The CSWPP supervisor shall review the site for ESC and SWPPS at least weekly and within 24 hours of significant storms. The CWSPP supervisor shall also review the site for ESC and SWPPS during periods of active construction where maintenance conditions change with construction activity (e.g., site grading operations, or concrete construction and dewatering operations for a detention vault). The City requires a written record of these reviews be kept on site with copies submitted to CED within 48 hours. Documentation If CED requires that a written record be maintained, standard ESC and SWPPS Maintenance Reports forms, included in Section D.4.1, may be used. A copy of all the required maintenance reports shall be kept on site throughout the duration of construction. Detailed maintenance requirements for each ESC measure are provided in Section D.2.1. Maintenance requirements for SWPPS BMPs are specified in Section D.2.2 (as in the case of BMPs related to concrete handling or material containment) or may be specified as part of a treatment or monitoring program, often accompanied with adjustment conditions of approval. Review Timing Weekly reviews shall be carried out every 6 to 8 calendar days. Reviews shall also take place within 24 hours of significant storms. In general, a significant storm is one with more than 0.5 inches of rain in 24 hours or less. Other indications that a storm is “significant” are if the sediment ponds or traps are filled with water, or if gullies form as a result of the runoff. Note: The site is to be in compliance with the regulations of this appendix at all times. The requirement for periodic reviews does not remove the applicant’s responsibility for having the site constantly in SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-108 compliance with Core Requirement #5 and the requirements of this appendix. The reviews are a mechanism to ensure that all measures are thoroughly checked on a regular basis and that there is documentation of compliance. The requirement for these reviews does not mean that CSWPP is to be ignored in between. D.2.4.5 FINAL STABILIZATION Prior to obtaining final construction approval, the site shall be stabilized, the structural ESC and SWPPS measures (such as silt fences, sediment traps, and concrete waste collection pits) removed, and drainage facilities cleaned. The removal of ESC and SWPPS measures is not required for those projects, such as plats, that will be followed by additional construction under a different permit. In these circumstances, the need for removing or retaining the measures must be evaluated on a site-specific basis. To obtain final construction approval, the following conditions must be met: 1. All disturbed areas of the site shall be vegetated or otherwise permanently stabilized. At a minimum, disturbed areas shall be seeded and mulched (see Section D.2.1.2.6) with a high likelihood that sufficient cover will develop shortly after final approval. Mulch without seeding is not adequate to allow final approval of the permit, except for small areas of mulch used for landscaping. The only exceptions to these requirements are lots within a plat that are to be developed under an approved residential permit immediately following plat approval. In these cases, mulch and/or temporary seeding are adequate for cover. 2. Structural measures such as, but not limited to, silt fences, pipe slope drains, construction entrances, storm drain inlet protection, sediment traps and ponds, concrete washout and collection pits, and pollutant storage shall be removed from the site. Measures that will quickly decompose, such as brush barriers and organic mulches, may be left in place. In the case of silt fences, it may be best to remove fences in conjunction with the seeding, since it may be necessary to bring machinery back in to remove them. This will result in disturbed soils that will again require protection. The CED inspector must approve an applicant’s proposal to remove fencing prior to the establishment of vegetation. In some cases, such as residential building following plat development, it shall be appropriate to leave some or all ESC measures for use during subsequent development. This shall be determined on a site- specific basis. 3. All permanent surface water facilities, including catch basins, manholes, pipes, ditches, channels, flow control facilities, and water quality facilities, shall be cleaned. Existing and newly constructed BMPs/facilities shall be cleaned and/or mitigated as necessary to restore functionality. Any offsite catch basin that required protection during construction (see Section D.2.1.5.3) shall also be cleaned. 4. If only the infrastructure of the site has been developed (e.g., subdivisions and short plats) with building construction to occur under a different permit, then the critical area buffers, Critical Area Tracts, or Critical Area Setback Areas shall be clearly marked as described in Section D.2.1.1 in order to alert future buyers and builders. D.2.4.6 NPDES REQUIREMENTS As part of NPDES implementation, projects that will disturb one or more acres for purposes of constructing or allowing for construction of a development, or projects disturbing less than one acre that are part of a larger common plan of development or sale13 that will ultimately disturb one or more acres, must apply for coverage under Ecology’s Construction Stormwater General Permit. In general, the 13 Common plan of development or sale means a site where multiple separate and distinct construction activities may take place at different times or on different schedules, but still under a single plan. Examples include: 1) phased projects and projects with multiple filings or lots, even if the separate phases or filings/lots will be constructed under separate contract or by separate owners (e.g., a development where lots are sold to separate builders); 2) a development plan that may be phased over multiple years, but is still under a consistent plan for long-term development; and 3) projects in a contiguous area that may be unrelated but still under the same contract, such as construction of a building extension and a new parking lot at the same facility. Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendix C Inspection and Maintenance Report Forms SECTION D.4 REFERENCE SECTION 12/12/2016 2017 City of Renton Surface Water Design Manual D-130 D.4.3 ESC AND SWPPS MAINTENANCE REPORTS CED may require a written record of all maintenance activities to be kept to demonstrate compliance with the Maintenance Requirements (Section D.2.4.4). A standard ESC Maintenance Report is provided on the next page and typical SWPPS Maintenance Reports follow. Copies of the ESC and SWPPS Maintenance Reports must be kept on site throughout the duration of construction. E S C M A I N T E N A N C E R E P O R T Performed By:___________________________ Date:___________________________ Project Name:___________________________ CED Permit #:___________________________ Clearing Limits Damage OK Problem Visible OK Problem Intrusions OK Problem Other OK Problem Mulch Rills/Gullies OK Problem Thickness OK Problem Other OK Problem Nets/Blankets Rills/Gullies OK Problem Ground Contact OK Problem Other OK Problem Plastic Tears/Gaps OK Problem Other OK Problem Seeding Percent Cover OK Problem Rills/Gullies OK Problem Mulch OK Problem Other OK Problem Sodding Grass Health OK Problem Rills/Gullies OK Problem Other OK Problem Perimeter Protection Including Silt Fence Damage OK Problem Sediment Build-up OK Problem Concentrated Flow OK Problem Other OK Problem BMP/Facility Protection Damage OK Problem Sedimentation OK Problem Concentrated Flow OK Problem Rills/Gullies OK Problem Intrusions OK Problem Other OK Problem Brush Barrier Damage OK Problem Sediment Build-up OK Problem Concentrated Flow OK Problem Other OK Problem D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2017 City of Renton Surface Water Design Manual 12/12/2016 D-131 Vegetated Strip Damage OK Problem Sediment Build-up OK Problem Concentrated Flow OK Problem Other OK Problem Construction Entrance Dimensions OK Problem Sediment Tracking OK Problem Vehicle Avoidance OK Problem Other OK Problem Wheel Wash Dimensions OK Problem Sed buildup or tracking OK . Problem Other OK Problem Construction Road Stable Driving Surf. OK Problem Vehicle Avoidance OK Problem Other OK Problem Sediment Trap/Pond Sed. Accumulation OK Problem Overtopping OK Problem Inlet/Outlet Erosion OK Problem Other OK Problem Catch Basin/Inlet Protection Sed. Accumulation OK Problem Damage OK Problem Clogged Filter OK Problem Other OK Problem Interceptor Dike/Swale Damage OK Problem Sed. Accumulation OK Problem Overtopping OK Problem Other OK Problem Pipe Slope Drain Damage OK Problem Inlet/Outlet OK Problem Secure Fittings OK Problem Other OK Problem Ditches Damage OK Problem Sed. Accumulation OK Problem Overtopping OK Problem Other OK Problem Outlet Protection Scour OK Problem Other OK Problem Level Spreader Damage OK Problem Concentrated Flow OK Problem Rills/Gullies OK Problem Sed. Accumulation OK Problem Other OK Problem Dewatering Controls Sediment OK Problem Dust Control Palliative applied OK Problem SECTION D.4 REFERENCE SECTION 12/12/2016 2017 City of Renton Surface Water Design Manual D-132 Miscellaneous Wet Season Stockpile OK Problem Other OK Problem Comments: Actions Taken: Problems Unresolved: D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2017 City of Renton Surface Water Design Manual 12/12/2016 D-133 Pollution Prevention Team Completed by: ______________________ Title: ______________________________ Date: ______________________________ Responsible Official: Title: ___________________________ Team Leader: Office Phone:____________________ Cell Phone #: ____________________ Responsibilities: _______________________________ _______________________________ _______________________________ (1) Title:____________________________ Office Phone: ____________________ Cell Phone #: ____________________ Responsibilities: _______________________________ _______________________________ _______________________________ (2) Title:____________________________ Office Phone: ____________________ Cell Phone #: ____________________ Responsibilities: _______________________________ _______________________________ _______________________________ D.4 REFERENCE SECTION 11/2/2016 2017 City of Renton Surface Water Design Manual D-134 Employee Training Completed by:______________________________________ Title:______________________________________________ Date: ______________________________________________ Describe the annual training of employees on the SWPPP, addressing spill response, good housekeeping, and material management practices. Training Topics 1.) LINE WORKERS Brief Description of Training Program/Materials (e.g., film, newsletter course) Schedule for Training (list dates) Attendees Spill Prevention and Response Good Housekeeping Material Management Practices 2.) P2 TEAM: SWPPP Implementation Monitoring Procedures D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2017 City of Renton Surface Water Design Manual 11/2/2016 D-135 List of Significant Spills and Leaks Completed by: Title: Date: List all spills and leaks of toxic or hazardous pollutants that were significant but are not limited to, release of oil or hazardous substances in excess of reportable quantities. Although not required, we suggest you list spills and leaks of non-hazardous materials. Description Response Procedure Date (month/day/ year) Location (as indicated on site map) Type of Material Quantity Source, If Known Reason for Spill/Leak Amount of Material Recovered Material No longer exposed to Stormwater (Yes/No) Preventive Measure Taken D.4 REFERENCE SECTION 12/12/2016 2017 City of Renton Surface Water Design Manual D-136 Potential Pollutant Source Identification Completed by: Title: Date: List all potential stormwater pollutants from materials handled, treated, or stored onsite. Potential Stormwater Pollutant Stormwater Pollutant Source Likelihood of pollutant being present in your stormwater discharge. If yes, explain D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2017 City of Renton Surface Water Design Manual 12/12/2016 D-137 Material Inventory Completed by: Title: Date: List materials handled, treated, stored, or disposed of at the project site that may potentially be exposed to precipitation or runoff. Material Purpose/Location Quantity (Units) Likelihood of contact with stormwater Past Spill or Used Produced Stored If Yes, describe reason Leak (indicate per week or year) Yes No Construction Stormwater Pollution Prevention Plan Northwest Gourmet Freezer Addition AHBL No. 2160966.10 Appendix D Geotechnical Report By E3RA, Inc., May 22, 2013