The URL can be used to link to this page

Home My WebLink AboutRS_Technical_Information_Report_180614_v2.pdf Washington State Auto Dealers Association (WSADA) Renton Parking Lot Technical Information Report Prepared for: Washington State Auto Dealers Association 621 SW Grady Way Renton, WA 98057 Contact: Vicki Giles Fabré Phone: (206) 433-6300 Prepared by: Sitts & Hill Engineers, Inc. 4815 Center Street Tacoma, Washington 98409 Contact: Kathy Hargrave, P.E. Phone: (253) 474-9449 May 2018 Revised June 2018 S&H Job Number 17,668 Washington State Auto Dealers Association (WSADA) Renton Parking Lot Technical Information Report Prepared for: Washington State Auto Dealers Association 621 SW Grady Way Renton, WA 98057 Contact: Vicki Giles Fabré Phone: (206) 433-6300 Prepared by: Sitts & Hill Engineers, Inc. 4815 Center Street Tacoma, Washington 98409 Contact: Kathy Hargrave, P.E. Phone: (253) 474-9449 May 2018 Revised June 2018 S&H Job Number 17,668 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON i TABLE OF CONTENTS 1.0 PROJECT OVERVIEW .............................................................................................................. 3 1.1 Scope ............................................................................................................................................................... 3 1.2 Existing Conditions ........................................................................................................................................ 4 1.3 Proposed Conditions ..................................................................................................................................... 4 2.0 Conditions and Requirements Summary .............................................................................. 6 2.1 Discussion of Core and Special Requirements ......................................................................................... 6 2.1.1 Core Requirement #1: Discharge at the Natural Location ................................................................ 6 2.1.2 Core Requirement #2: Offsite Analysis ................................................................................................ 6 2.1.3 Core Requirement #3: Flow Control ..................................................................................................... 6 2.1.4 Core Requirement #4: Conveyance System ....................................................................................... 6 2.1.5 Core Requirement #5: Erosion and Sediment Control ...................................................................... 6 2.1.6 Core Requirement #6: Maintenance and Operations ........................................................................ 6 2.1.7 Core Requirement #7: Financial Guarantees and Liability ............................................................... 7 2.1.8 Core Requirement #8: Water Quality ................................................................................................... 7 2.1.9 Core Requirement #9: Onsite BMPs .................................................................................................... 7 2.1.10 Special Requirement #1: Other Adopted Area-Specific Requirements ........................................ 8 2.1.11 Special Requirement #2: Flood Hazard Area Delineation .............................................................. 8 2.1.12 Special Requirement #3: Flood Protection Facilities ....................................................................... 8 2.1.13 Special Requirement #4: Source Control .......................................................................................... 8 2.1.14 Special Requirement #5: Oil Control .................................................................................................. 8 2.1.15 Special Requirement #6: Aquifer Protection Areas ......................................................................... 8 3.0 OFF-SITE ANALYSIS .............................................................................................................. 11 3.1 Define and Map the Study Area Study Area ............................................................................................ 11 3.2 Resource Review ......................................................................................................................................... 13 3.3 Field Inspection ............................................................................................................................................ 13 3.4 Drainage System Description and Problem Descriptions ...................................................................... 13 3.5 Mitigation of Existing or Potential Problems ............................................................................................. 13 4.0 FLOW CONTROL, LID, AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ..... 14 4.1 Existing Site Hydrology ............................................................................................................................... 14 4.2 Developed Site Hydrology .......................................................................................................................... 14 4.3 Performance Standards .............................................................................................................................. 14 4.4 Flow Control System .................................................................................................................................... 14 4.4.1 Flow Control Exemptions Check ......................................................................................................... 14 4.4.2 Flow Control Area .................................................................................................................................. 14 4.4.3 Flow Control Area Requirements and Exceptions ........................................................................... 14 4.4.4 Identify Applicable Flow Control BMPs per Core Requirement #9 ................................................ 16 4.5 Water Quality ................................................................................................................................................ 16 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................................................ 17 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON ii 6.0 SPECIAL REPORTS AND STUDIES ...................................................................................... 19 7.0 OTHER PERMITS .................................................................................................................... 20 8.0 CSWPPP ANALYSIS AND DESIGN ....................................................................................... 21 9.0 BOND QUANTITIES and R/D FACILITY SUMMARIES ........................................................ 22 9.1 Bond Quantities ............................................................................................................................................ 22 9.2 Facility Summaries ....................................................................................................................................... 22 10.0 OPERATIONS AND MAINTENANCE MANUAL .................................................................. 23 10.1 Purpose ....................................................................................................................................................... 23 10.2 Permanent Facilities Description ............................................................................................................. 23 10.3 Discussion of Maintenance....................................................................................................................... 23 10.4 Maintenance Frequency ........................................................................................................................... 24 10.5 Annual Cost Estimate ................................................................................................................................ 24 TABLE OF APPENDICES A.1 TIR Worksheet A.2 Bond Quantity Worksheet A.3 Stormwater Engineering Calculations A.4 Geotechnical Engineering Report WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 3 1.0 PROJECT OVERVIEW 1.1 Scope This Technical Information Report (TIR) addresses improvements associated with the proposed parking lot located at 620 SW 12th Street, Renton, WA (Parcel No. 3340404805). Please see Figure 1 for the Site Location Map. This parking lot is to serve as surplus parking for Washington State Auto Dealers Association (WSADA) 621 SW Grady Way, parcel number 3340404730. This project proposes to develop a vacant lot to create surplus parking for the WSADA building. The parking lot will have driveway connections to SW 12th Street and an existing paved alley to the north. This Technical Information Report has been prepared in accordance with the 2017 City of Renton Surface Water Design Manual (SWDM). A copy of the TIR Worksheet, which provides basic information about the scope of this project, is included with this report in Appendix A.1. Figure 1 – Site Location Map WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 4 1.2 Existing Conditions The subject site is located on 0.33 acre of vacant land consisting of grass, low growing bushes, and trees along the eastern extent. The site, as depicted on the topographical survey, was previously highest in elevation in the center and sloped towards the edges of the parcel (9 feet of approximate vertical drop). Since the development of the topographic survey, the onsite stockpile of dirt has been since removed. This TIR asserts that the stockpile and its environmental effects are accounted for within this report and permit application. Upon a visual examination of existing site conditions, stormwater runoff on the north side of the site discharges to the adjacent alley, and runoff on the south side of the site discharges to SW 12th Street. Stormwater discharging to the alley to the north is captured by the existing 12-inch stormwater main (R-365730). There is no existing stormwater main within SW 12th Street, and stormwater flowing to the south is believed to be dispersed and undergo evapotranspiration. During heavy rainfall events, puddling along the site frontage is also possible. Based upon a review of available information on the City of Renton’s GIS as well as a field visit, we are not aware of any capacity problems with the existing drainage facilities adjacent to this area. The City of Renton’s Public Works Maps combined with King County GIS together indicate the site is not located within or near any critical areas. In addition, it is located within the Peak Rate Flow Control Standard Zone. 1.3 Proposed Conditions The purpose of site improvements for this project is to create additional parking for the WSADA building located immediately north of the site. The project proposes grading, paving, landscaping, and drainage (water quality facilities, conveyance piping, and gravel filled trenches) improvements. See Table 1 for a description of existing and proposed surface conditions. The site is located within the Black River Drainage Basin and thus stormwater runoff generated onsite will be subject to enhanced basic water quality treatment before being conveyed to the conveyance system located within the City’s right-of-way. The treatment requirement will be met by two Filterra® units. The flow control requirement will be met without the need for a new flow control facility (see Section 4.0 of this report). Please see Appendix A.3 for the subbasin exhibit as it outlines each Filterra’s ® tributary area. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 5 Table 1. Existing and Developed Condition Description Description Onsite Offsite Total Existing Conditions Total Project Area (ft2) 14,695 980 15,675 Existing hard surface (ft2) 10,140 980 11,120 Existing landscaping/lawn area (ft2) 4,555 0 4,555 Developed Conditions Total Project Area (ft2) 14,695 980 15,675 Amount of new hard surface (ft2) 11,067 592 11,659 Amount of new pollution generating hard surface (PGHS) (ft2) 11,067 592 11,659 Amount of replaced hard surface (ft2) 225 388 613 Amount of replaced PGHS (ft2) 0 143 143 Amount of new plus replaced hard surface (ft2) 11,292 980 12,272 Amount of new plus replaced PGHS (ft2) 11,067 735 11,802 Amount of existing hard surfaces converted to vegetation/landscaping (ft2) 3,403 0 3,403 Amount of Land Disturbed (ft2) 14,695 980 15,675 Native Vegetation to Pasture (acres) 0 0 0 Existing vegetation area to remain (ft2) 0 0 0 Existing hard surface to remain unaltered (ft2)15,700 0 0 0 Value of proposed improvements ($) 380,000 20,000 400,000 Amount to be Graded/Approx. CUT (C.Y.) 2,019 0 2,019 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 6 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Discussion of Core and Special Requirements This is a medium industrial (IM) project that adds more than 2,000 square feet of new and replaced impervious surface. Therefore, the project is subject to a full drainage review and must satisfy all core requirements (1-9) and all special requirements (1-6) of the 2017 City of Renton Surface Water Design Manual (SWDM). See “Figure 2 – Drainage Review Flow Chart” at the end of this Section. Below is a description of each core requirement and how the project proposes to satisfy each requirement. 2.1.1 Core Requirement #1: Discharge at the Natural Location This requirement will be met by discharging surface water to its existing (natural) location. 2.1.2 Core Requirement #2: Offsite Analysis The Off-Site Analysis included in Section 3.0 of this TIR will satisfy this Core Requirement. 2.1.3 Core Requirement #3: Flow Control Please see Section 4.0 for a discussion of flow control for the project. The project proposes work within the Peak Rate Flow Control Standards (Existing Site Conditions) Area. The project must match the developed peak discharge rates to the existing site conditions peak discharge rates for the 2-, 10-, and 100-year return periods. When modeled in WWHM, a Washington State Department of Ecology- approved continuous rainfall runoff modeling program, this project resulted in a decrease of peak rates for the 2-, 10-, and 100-year return events. Per Section 1.2.3.1.A, Exception 1, of the SWDM, the target surfaces subject to the Peak Rate Flow Control Standard Areas facility requirements will generate no more than a 0.15-cfs increase in the existing site conditions 100-year peak flow. Therefore, this project does not propose a flow control facility. 2.1.4 Core Requirement #4: Conveyance System Please see Section 5.0 of this TIR for the conveyance system analysis and design. This project proposes a new conveyance system in order to manage stormwater runoff within the proposed parking lot in accordance with the requirements presented in Volume 1 Section 1.2.4.1 of the City of Renton SWDM. The site has been graded to convey water to either one of two Filterra® units located on the west and east corners of the parking lot. 2.1.5 Core Requirement #5: Erosion and Sediment Control A temporary Erosion and Sediment Control Plan (TESC) has been prepared and included in the plan set. Additionally, a CSWPPP under separate cover, has been provided to satisfy this requirement. 2.1.6 Core Requirement #6: Maintenance and Operations Please see Section 10.0 of this TIR for the Operations and Maintenance Manual, prepared to satisfy this Core Requirement. Washington State Auto Dealers Association will be responsible for maintenance and operation of the proposed on-site stormwater facilities upon completion. The City of Renton will continue to be responsible for operation and maintenance of the right-of-way. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 7 2.1.7 Core Requirement #7: Financial Guarantees and Liability The project anticipates that Washington State Auto Dealers Association will be required to provide a Construction Bond to the City of Renton prior to issuance of the permit. The contractor/owner will be responsible for all erosion and maintenance liabilities during construction. 2.1.8 Core Requirement #8: Water Quality Please see Section 4.0 for a discussion of water quality for the project. The project proposes two Filterra® units by Contech, which satisfies the Manual’s water quality requirement for enhanced basic treatment. When modeled in WWHM, the unit provided more than the required 91% treatment for each subbasin. 2.1.9 Core Requirement #9: Onsite BMPs Target surfaces subject to Core Requirement #9 Onsite BMPs include new impervious surfaces, new pervious surfaces, and replaces impervious surfaces, not already mitigated with an approved onsite BMP. This site qualifies for the Small Lot BMP Requirements Per 1.2.9.2.1 of the City of Renton SWDM, since it is smaller than 22,000 square feet. This project proposes to implement BMPs as feasible and applicable. Full Dispersion – Historically, this site has not supported a forested condition via a preserved tract, easement or covenant. In order to meet this requirement, this type of surface condition is required, per Section C2.1 of the City of Renton SWDM, therefore, full dispersion is not feasible or applicable. Full Infiltration – Per Section C2.2 of the City of Renton SWDM, full infiltration requires the use of BMPs that can “fully and reliably” infiltrate runoff into the ground. “Fully” in this context means all runoff from nearly all storm events is soaked into the ground. “Reliably” means that soils conditions are favorable enough to ensure that the device used to infiltrate runoff into the ground will perform as expected. This site’s native soils are Class D soils, indicating that infiltration of all stormwater runoff for every storm event onsite is not favorable. Please see the Appendix A.4 for a Geotechnical Report, which states “native soils were all poorly consolidated and oversaturated.” Limited Infiltration – Limited infiltration is the use of infiltration devices from Section C2.3 of the City of Renton SWDM, in soils that are not as permeable as the soils targeted for full infiltration in Section C2.2. This site, per the Geotechnical Report provided in Appendix A.4, states that the site characteristically supports sandy loam, which qualifies for the implementation of limited infiltration devices onsite. This project proposes to implement Gravel Filled Trenches for Limited Infiltration per C2.3.3 of the City of Renton SWDM. Per Paragraph 5 of Section 1.2.9.2.1, for lot sizes between 11,000 and 22,000 square feet (project lot size is 14,500 square feet), BMPs must be implemented for an impervious area equal to at least 20% of the lot area (2,900 square feet). The perforated conveyance piping onsite will be constructed within gravel filled trenches in order to meet the requirement outlined in C2.3.3. For every 1,000 square feet of targeted tributary impervious surface, a prescriptive 36 feet of trench length is required. Therefore, this site is required to provide WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 8 105LF of gravel filled trenches. This length of infiltration trench can be accommodated along the conveyance piping between the two proposed Filterra units. Rain Gardens – Rain gardens are not feasible onsite, the space allocated for a rain garden would not be able to gravity flow back to the City’s conveyance system. Bioretention – Bioretention devices are not feasible onsite since the native soils (Class D) have a compacted layer of soil which severely limited soaking capacity and causes water to perch on the relatively impervious layer during the wet season, see the Geotechnical Report provided in Appendix A.4. This makes bioretention impractical, unreliable, and reduces plant survivability in the system. Permeable Pavement – Permeable pavement is not feasible onsite, for native soils do not allow water to infiltrate, per the Geotechnical Report provided in Appendix A.4. Soil limitations are also outlined in C2.7 of the City of Renton SWDM. The water would site within the pavement and would erode overtime. 2.1.10 Special Requirement #1: Other Adopted Area-Specific Requirements N/A. The project site is not in a designated critical drainage area or in an area included in an adopted master drainage plan, basin plan, salmon conservation plan, stormwater compliance plan, flood hazard management plan, lake management plan, or shared facility drainage plan. 2.1.11 Special Requirement #2: Flood Hazard Area Delineation N/A. Per the FEMA floodplain map at the end of this Section, Figure 3, the project site lies within Zone X which is defined as “areas determined to be outside 500-year floodplain” and therefore flood-related delineation on the project site is not required. 2.1.12 Special Requirement #3: Flood Protection Facilities N/A. This project does not propose to rely on an existing flood protection facility nor does it modify or construct a new flood protection facility. 2.1.13 Special Requirement #4: Source Control WSADA shall implement Operational and Structural Source Control BMPs that includes the maintenance of stormwater drainage and treatment systems as described in the Operations and Maintenance Manual, included in Section 10.0 of this report. 2.1.14 Special Requirement #5: Oil Control This project does not propose to develop a high-use site as defined by City of Renton SWDM; therefore, this Special Requirement is not applicable. 2.1.15 Special Requirement #6: Aquifer Protection Areas This project is not located within an Aquifer Protection Area per King County GIS. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 9 Figure 2 – Drainage Review Flow Chart WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 10 Figure 3 – FEMA Map WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 11 3.0 OFF-SITE ANALYSIS Per City of Renton SWDM Section 1.2.2, this project must provide an off-site analysis report that assesses potential off-site drainage and water quality impacts associated with the redevelopment of the project site. The level of analysis required depends on the specific site and downstream conditions. In accordance with Section 1.2.2.1, a Level 1 Downstream Analysis has been performed. 3.1 Define and Map the Study Area Based on the existing topography and soil characteristics, the site is mostly tributary to the City’s existing conveyance system. Those portions of the site that do not discharge to the City’s existing conveyance system likely disperse across vegetation. The project site does not have an existing conveyance system. The project does not propose any significant improvements to the existing conveyance elements within the alley right-of-way to the north of the site. A topographical site map is featured in Figure 4 of this Report. TPN 3340404805 S.W. 12TH S T . R Call 811 two business days before you dig LEGEND HORIZONTAL DATUM VERTICAL DATUM SITE DATA NOTES LEGAL DESRIPTION REFERENCES IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN WSADA PARKING LOT A-NNNNNNN PHONE: (253) 474-9449 | FAX: (253) 474-0153 4815 CENTER STREET | TACOMA, WA. 98409 SITTS & HILL ENGINEERS, INC. CIVIL STRUCTURAL SURVEYING http://www.sittshill.com/ TOPOGRAPHIC SURVEY WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 13 3.2 Resource Review A thorough review of the resources provided by the City of Renton Maps, as outlined on page 2-11 of the SWDM, has been completed for the study area. Research conducted on 2/14/2018 has shown that there are not any adopted basin plans available for the study area. According to the FEMA Map presented in Figure 3 of this report, the project site lies within Zone X, which is defined as areas outside the 500-year floodplain. The site is located within the Duwamish – Green River Watershed, the Black River Basin, and the Springbrook Creek Sub Basin. Based on the City of Renton GIS, the project area has not been defined as a sensitive area. There have not been any reported road drainage problems associated with the roads surrounding the site. It was also found that the site does not have a migrating river study, a 303d listing, or an adopted stormwater compliance plan available. Please see Section 4.0 for a discussion of water quality for the project. A geotechnical report completed by Migizi Group can be found in Appendix A.4. 3.3 Field Inspection During field inspections on May 9, 2018, the weather was fair with no precipitation during the inspection. The existing conveyance system located within the alley to the north of the project site appeared to be working sufficiently. We do not anticipate any future problems with the proposed stormwater system additions. The amount of area tributary to the existing conveyance system will remain largely the same – there is not a substantive increase in stormwater runoff tributary to the existing conveyance system as a result of this project. Please see Section A.3 Flow Control for the modeled areas in the predeveloped and mitigated scenarios. Since it has been determined that there are no anticipated stormwater problems associated with this project, Level 2 and Level 3 downstream analyses are not required. No problems were found related to constrictions, capacity deficiencies, flooding, scouring, overtopping hazards, sedimentation or erosion, aquatic organisms or their habitation. Land use associated with the study area includes medium industrial/commercial land applications such as a veterinary hospital and advanced technology construction. In addition, the study area includes BPA utilities and roadways. Existing impervious surfaces located within the study area include four commercial businesses, compacted gravel access, paved parking lots, paved driveways, and the paved public right-of-way. Based on existing site topography, stormwater runoff is captured within the City’s right-of-way where it is collected by a storm conveyance system and discharged to the Black River. 3.4 Drainage System Description and Problem Descriptions No drainage system problems were observed during the field inspection. 3.5 Mitigation of Existing or Potential Problems The proposed project area does not have any existing or anticipated drainage problems as outlined in Section 1.2.2.1 of the City of Renton SWDM. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 14 4.0 FLOW CONTROL, LID, AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 4.1 Existing Site Hydrology The project site surfacing consists of existing compacted gravel and soil, with some areas of landscaping. The site previously had a mound of soil located centrally onsite which slopes from the center down towards the parcels limits. The site is tributary to the City’s conveyance system located within the alley to the north of the site, as well as to the south, SW 12th Street. 4.2 Developed Site Hydrology The proposed site will be comprised of new asphalt pavement and landscape areas. In the developed condition, approximately 6,440 sf of area which was previously discharged to the south will now discharge to the north. The project does not propose to alter the downstream flow path and will maintain discharge to the natural location. 4.3 Performance Standards The site is within a Peak Rate Flow Control Standards (Existing Site Conditions) Area, which requires matching the existing site conditions 2-, 10-, and 100- year peak flows. The predeveloped site is comprised of compacted gravel, soil and landscaping. The proposed site conditions include both paved areas as well as landscaping. In areas where conveyance features are required, they have been designed in accordance with Section 1.2.4 of the SWDM. The proposed conveyance elements include two Filterra® units, a Type 1 catch basin and associated piping to connect to the manhole within the alley right-of-way, see Section 4.5 of this report. 4.4 Flow Control System N/A. No flow control systems are required or provided for this site. 4.4.1 Flow Control Exemptions Check The project site is not exempt from flow control, since more than 5,000 square feet of new plus replaced impervious surfaces are proposed. However, the project proposes to decrease the 2-, 10-, and 100-year peak rate runoffs. These results are displayed in WWHM and the results can be found in Appendix A.3, Flow Control. Therefore, this requirement has been met. 4.4.2 Flow Control Area The site falls within a Peak Rate Flow Control Standard – Match Existing Area, based on the Flow Control Application Map provided by the City of Renton (Figure 4 of this TIR). 4.4.3 Flow Control Area Requirements and Exceptions Peak Rate Flow Control Standard-Match Existing areas must match existing site conditions 2-,10-, and 100-year peak rate runoff for areas draining to constructed (man-made) or highly modified drainage systems so as to not create a downstream flooding problem. Per Section 1.2.3.1.A, Exception 1, of the SWDM, the target surfaces subject to the Peak Rate Flow Control Standard Areas facility requirements WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 15 will generate no more than a 0.15-cfs increase in the existing site conditions 100-year peak flow. Therefore, this project does not propose a flow control facility. Figure 4- City of Renton Flow Control Application Map WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 16 4.4.4 Identify Applicable Flow Control BMPs per Core Requirement #9 Please see Section 2.1.9 of this report for an evaluation of Flow Control BMPs per Core Requirement #9. 4.5 Water Quality As mentioned in Section 4.3, the project proposes to satisfy the enhanced water quality requirement by installing two Filterra® units, providing over 91% treatment for the subbasin runoff volume. Please see the subbasin exhibit provided in Appendix A.3. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 17 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN The sole conveyance element proposed on this project are the 8”, 10” and 12” storm drain pipes. The conveyance elements have has been analyzed for capacity during the 25-year event, as estimated using the 15-minute time step in WWHM. The area tributary (see Appendix A.3) to the existing manhole within the alley to the north of the site is: Pervious (C, Lawn, Flat) = 0.0644 acres Impervious (Paving, Flat) = 0.257 acres Q25= 0.18 cfs Flow Frequency Results: Conveyance calculations are provided below per the Uniform Flow Analysis Method provided by the City of Renton SWDM Section 4.2.1.2. Each pipe within the system is sized and sloped such that its barrel capacity at normal full flow (computed by Manning’s equation) is equal to or greater than the design flow (25 year peak flow rate). = 1.49 Where: Q= Flow rate (cfs) WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 18 n = Manning’s Roughness coefficient A = Area of the pipe (sf) R = Hydraulic Radius (ft) S = Channel Slope (ft/ft) The design flow was found from WWHM and equals 0.18 cfs. The barrel capacities at normal full flow for the CPEP conveyance pipes are provided below: Pipe Size (inches) A (sf) R(ft) n S (ft/ft) Q-Normal (cfs) Q-Design (cfs) 8 0.349 0.167 0.014 0.0767 3.12 0.18 8 0.349 0.208 0.014 0.0124 1.25 0.18 12 0.785 0.25 0.014 0.0122 3.66 0.18 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 19 6.0 SPECIAL REPORTS AND STUDIES We are not aware of any site characteristics that are particularly sensitive to stormwater runoff. A geotechnical report by Migizi Group can be found in Appendix A.4 of this report. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 20 7.0 OTHER PERMITS In addition to a Clear and Grade Permit, we anticipate that a Right-of-Way Use permit, Land Use Master Application, Civil Construction Permit and an Environmental Review Permit (SEPA) will be required. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 21 8.0 CSWPPP ANALYSIS AND DESIGN See the Construction Stormwater Pollution Prevention Plan report which has been included with this submittal under a separate cover. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 22 9.0 BOND QUANTITIES AND R/D FACILITY SUMMARIES 9.1 Bond Quantities See Appendix A.2 for a copy of the City of Renton bond report. 9.2 Facility Summaries This project does not propose to implement any Retention / Detention (R/D) facilities, but the project will install two water quality facilities as previously discussed in Section 4.0. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 23 10.0 OPERATIONS AND MAINTENANCE MANUAL 10.1 Purpose The purpose of this manual is to provide guidelines for maintaining the storm drainage system as a part of the parking lot expansion for WSADA. This existing building and associated parking lot are located northwest of the project site. The site address is 620 SW 12th Street, Renton, WA 98057. Storm utility improvements that have been proposed as a part of the project include: o Type 1 Catch Basin o Filterra® Units o Storm Drainage Piping Each portion of the system has to be maintained in good working condition for the system to function properly. Operations and Maintenance of the drainage systems will be the responsibility of the Owner, WSADA. Vicki Giles Fabré is the contact person at WSADA. Her contact information is: Vicki Giles Fabré Washington State Auto Dealers Association 621 Southwest Grady Way Renton, WA 98057 Phone: (206) 433-6300 The City of Renton will continue to be responsible for the Operation and Maintenance of the alley right- of-way located to the north of the site. 10.2 Permanent Facilities Description The proposed Filterra® units located within the parking lot will treat and conveyance piping will convey water back to the City’s main. The project does not propose to alter downstream flow paths and will maintain ultimate discharge to the Black River. 10.3 Discussion of Maintenance Any buildup of sediment, debris, vegetation, or trash that impedes the designed Filterra® unit(s), or the Type 1 catch basin will reduce the storm system capacity. As a result, care must be taken to keep all inlets clear of debris. The applicable maintenance checklists and excerpts from the 2017 SWDM have been included with the Operations and Maintenance Manual for review during routine maintenance inspections. In addition, the Filterra’s Owner Manual from Contech has been provided for ease of reference. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 24 10.4 Maintenance Frequency Following construction of the project, the storm drainage system shall be inspected and maintained according to their respective maintenance checklists included at the end of this manual. Facilities will be inspected annually, or after every significant storm event where the precipitation is greater than or equal to one inch in 24 hours When deficiencies are noted, the problems are to be corrected as soon as possible. Any spill of hazardous material (e.g. fuel, lubricant, herbicide, etc.) shall be cleaned up immediately and shall be reported to the Division of Emergency Management (1-800-523-5044). Contaminated material will be disposed of properly. Any questions about the existence of a problem should be directed to a Professional Engineer. 10.5 Annual Cost Estimate Annual maintenance costs for the proposed storm system, including two Filterra® units, a Type 1 catch basin, and conveyance piping, have been estimated to be $1,850. WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 25 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 26 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 27 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 28 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 29 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 30 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 31 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 32 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 33 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 34 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 35 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 36 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 37 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 38 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 39 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 40 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 41 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 42 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 43 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 44 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 45 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 46 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 47 Cover Sheet for Inspection Forms Name of Inspector: _____________________________________________________________ Date of Inspection: _____________________________________________________________ Number of Sheets Attached: _____________________________________________________________ Inspector’s Signature: _____________________________________________________________ WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 48 Maintenance Log Action Taken Name Date How Procedure Was Performed Problems Encountered Additional Actions Recommended WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 49 A.1 TIR Worksheet WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 50 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 51 © WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 52 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 53 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 54 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 55 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON A.2 Bond Quantity Worksheet CED Permit #:########UnitReference #PriceUnitQuantity CostBackfill & compaction-embankmentESC-16.50$ CY Check dams, 4" minus rockESC-2SWDM 5.4.6.380.00$ Each Catch Basin ProtectionESC-335.50$ Each271.00Crushed surfacing 1 1/4" minusESC-4WSDOT 9-03.9(3)95.00$ CY DitchingESC-59.00$ CY Excavation-bulkESC-62.00$ CYFence, siltESC-7SWDM 5.4.3.11.50$ LF490735.00Fence, Temporary (NGPE)ESC-81.50$ LF Geotextile FabricESC-92.50$ SY Hay Bale Silt TrapESC-100.50$ Each HydroseedingESC-11SWDM 5.4.2.40.80$ SY Interceptor Swale / DikeESC-121.00$ LF Jute MeshESC-13SWDM 5.4.2.23.50$ SY Level SpreaderESC-141.75$ LF Mulch, by hand, straw, 3" deepESC-15SWDM 5.4.2.12.50$ SY Mulch, by machine, straw, 2" deepESC-16SWDM 5.4.2.12.00$ SY Piping, temporary, CPP, 6"ESC-1712.00$ LF Piping, temporary, CPP, 8"ESC-1814.00$ LF Piping, temporary, CPP, 12"ESC-1918.00$ LF Plastic covering, 6mm thick, sandbaggedESC-20SWDM 5.4.2.34.00$ SY180720.00Rip Rap, machine placed; slopesESC-21WSDOT 9-13.1(2)45.00$ CY Rock Construction Entrance, 50'x15'x1'ESC-22SWDM 5.4.4.11,800.00$ Each11,800.00Rock Construction Entrance, 100'x15'x1'ESC-23SWDM 5.4.4.13,200.00$ Each Sediment pond riser assemblyESC-24SWDM 5.4.5.22,200.00$ Each Sediment trap, 5' high berm ESC-25SWDM 5.4.5.119.00$ LF Sed. trap, 5' high, riprapped spillway berm section ESC-26SWDM 5.4.5.170.00$ LF Seeding, by handESC-27SWDM 5.4.2.41.00$ SY Sodding, 1" deep, level groundESC-28SWDM 5.4.2.58.00$ SY Sodding, 1" deep, sloped groundESC-29SWDM 5.4.2.510.00$ SY TESC SupervisorESC-30110.00$ HR404,400.00Water truck, dust controlESC-31SWDM 5.4.7140.00$ HR405,600.00UnitReference #PriceUnitQuantity Cost EROSION/SEDIMENT SUBTOTAL:13,326.00SALES TAX @ 10%1,332.60EROSION/SEDIMENT TOTAL:14,658.60(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescription No.(A)WRITE-IN-ITEMS Page 3 of 14Ref 8-H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostGENERAL ITEMS Backfill & Compaction- embankmentGI-16.00$ CYBackfill & Compaction- trenchGI-29.00$ CYClear/Remove Brush, by hand (SY)GI-31.00$ SYBollards - fixedGI-4240.74$ EachBollards - removableGI-5452.34$ EachClearing/Grubbing/Tree RemovalGI-610,000.00$ Acre0.333,300.00Excavation - bulkGI-72.00$ CYExcavation - TrenchGI-85.00$ CYFencing, cedar, 6' highGI-920.00$ LFFencing, chain link, 4'GI-1038.31$ LFFencing, chain link, vinyl coated, 6' highGI-1120.00$ LFFencing, chain link, gate, vinyl coated, 20' GI-121,400.00$ EachFill & compact - common barrowGI-1325.00$ CYFill & compact - gravel baseGI-1427.00$ CYFill & compact - screened topsoilGI-1539.00$ CYGabion, 12" deep, stone filled mesh GI-1665.00$ SYGabion, 18" deep, stone filled mesh GI-1790.00$ SYGabion, 36" deep, stone filled meshGI-18150.00$ SYGrading, fine, by handGI-192.50$ SYGrading, fine, with graderGI-202.00$ SY16603,320.00Monuments, 3' LongGI-21250.00$ EachSensitive Areas SignGI-227.00$ EachSodding, 1" deep, sloped groundGI-238.00$ SYSurveying, line & gradeGI-24850.00$ Day32,550.00Surveying, lot location/linesGI-251,800.00$ Acre0.33594.00Topsoil Type A (imported)GI-2628.50$ CY1654,702.50Traffic control crew ( 2 flaggers )GI-27120.00$ HRTrail, 4" chipped woodGI-288.00$ SYTrail, 4" crushed cinderGI-299.00$ SYTrail, 4" top courseGI-3012.00$ SYConduit, 2"GI-315.00$ LFWall, retaining, concreteGI-3255.00$ SFWall, rockeryGI-3315.00$ SFSUBTOTAL THIS PAGE:14,466.50(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)Page 4 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000syRI-130.00$ SYAC Grinding, 4' wide machine 1000-2000syRI-216.00$ SYAC Grinding, 4' wide machine > 2000syRI-310.00$ SYAC Removal/DisposalRI-435.00$ SY301,050.00Barricade, Type III ( Permanent )RI-556.00$ LFGuard RailRI-630.00$ LFCurb & Gutter, rolledRI-717.00$ LFCurb & Gutter, verticalRI-812.50$ LF4505,625.00Curb and Gutter, demolition and disposalRI-918.00$ LFCurb, extruded asphaltRI-105.50$ LFCurb, extruded concreteRI-117.00$ LFSawcut, asphalt, 3" depthRI-121.85$ LF205379.25Sawcut, concrete, per 1" depthRI-133.00$ LFSealant, asphaltRI-142.00$ LF205410.00Shoulder, gravel, 4" thickRI-1515.00$ SYSidewalk, 4" thickRI-1638.00$ SYSidewalk, 4" thick, demolition and disposalRI-1732.00$ SYSidewalk, 5" thickRI-1841.00$ SYSidewalk, 5" thick, demolition and disposalRI-1940.00$ SYSign, Handicap RI-2085.00$ Each2170.00Striping, per stallRI-217.00$ Each32224.00Striping, thermoplastic, ( for crosswalk )RI-223.00$ SFStriping, 4" reflectorized lineRI-230.50$ LFAdditional 2.5" Crushed SurfacingRI-243.60$ SYHMA 1/2" Overlay 1.5" RI-2514.00$ SYHMA 1/2" Overlay 2"RI-2618.00$ SYHMA Road, 2", 4" rock, First 2500 SYRI-2728.00$ SYHMA Road, 2", 4" rock, Qty. over 2500SYRI-2821.00$ SYHMA Road, 4", 6" rock, First 2500 SYRI-2945.00$ SY301,350.00HMA Road, 4", 6" rock, Qty. over 2500 SYRI-3037.00$ SYHMA Road, 4", 4.5" ATBRI-3138.00$ SYGravel Road, 4" rock, First 2500 SYRI-3215.00$ SYGravel Road, 4" rock, Qty. over 2500 SYRI-3310.00$ SYThickened EdgeRI-348.60$ LFSUBTOTAL THIS PAGE:3,189.256,019.00(B)(C)(D)(E)Page 5 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)PARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrowPL-121.00$ SY2" AC, 1.5" top course & 2.5" base coursePL-228.00$ SY129036,120.004" select borrowPL-35.00$ SY1.5" top course rock & 2.5" base coursePL-414.00$ SYSUBTOTAL PARKING LOT SURFACING:36,120.00(B)(C)(D)(E)LANDSCAPING & VEGETATIONNo.Street TreesLA-1Median LandscapingLA-236.00$ SY31511,340.00Right-of-Way LandscapingLA-32.00$ Wetland LandscapingLA-4SUBTOTAL LANDSCAPING & VEGETATION:11,340.00(B)(C)(D)(E)TRAFFIC & LIGHTINGNo.SignsTR-1100.00$ 1100.00Street Light System ( # of Poles)TR-2Traffic SignalTR-3Traffic Signal ModificationTR-4SUBTOTAL TRAFFIC & LIGHTING:100.00(B)(C)(D)(E)WRITE-IN-ITEMSParking Lot Light System (# of Poles)TR-5800.00$ 54,000.00SUBTOTAL WRITE-IN ITEMS:4,000.00STREET AND SITE IMPROVEMENTS SUBTOTAL:3,289.2571,945.50SALES TAX @ 10%328.937,194.55STREET AND SITE IMPROVEMENTS TOTAL:3,618.1879,140.05(B)(C)(D)(E)Page 6 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/DD-126.00$ SY* (CBs include frame and lid)BeehiveD-290.00$ EachThrough-curb Inlet FrameworkD-3400.00$ EachCB Type ID-41,500.00$ Each11,500.00CB Type ILD-51,750.00$ EachCB Type II, 48" diameterD-62,300.00$ Each for additional depth over 4' D-7480.00$ FTCB Type II, 54" diameterD-82,500.00$ Each for additional depth over 4'D-9495.00$ FTCB Type II, 60" diameterD-102,800.00$ Each for additional depth over 4'D-11600.00$ FTCB Type II, 72" diameterD-126,000.00$ Each for additional depth over 4'D-13850.00$ FTCB Type II, 96" diameterD-1414,000.00$ Each for additional depth over 4'D-15925.00$ FTTrash Rack, 12"D-16350.00$ EachTrash Rack, 15"D-17410.00$ EachTrash Rack, 18"D-18480.00$ EachTrash Rack, 21"D-19550.00$ EachCleanout, PVC, 4"D-20150.00$ EachCleanout, PVC, 6"D-21170.00$ EachCleanout, PVC, 8"D-22200.00$ EachCulvert, PVC, 4" D-2310.00$ LFCulvert, PVC, 6" D-2413.00$ LFCulvert, PVC, 8" D-2515.00$ LFCulvert, PVC, 12" D-2623.00$ LFCulvert, PVC, 15" D-2735.00$ LFCulvert, PVC, 18" D-2841.00$ LFCulvert, PVC, 24"D-2956.00$ LFCulvert, PVC, 30" D-3078.00$ LFCulvert, PVC, 36" D-31130.00$ LFCulvert, CMP, 8"D-3219.00$ LFCulvert, CMP, 12"D-3329.00$ LFSUBTOTAL THIS PAGE:1,500.00(B)(C)(D)(E)Quantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESPage 7 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, CMP, 15"D-3435.00$ LFCulvert, CMP, 18"D-3541.00$ LFCulvert, CMP, 24"D-3656.00$ LFCulvert, CMP, 30"D-3778.00$ LFCulvert, CMP, 36"D-38130.00$ LFCulvert, CMP, 48"D-39190.00$ LFCulvert, CMP, 60"D-40270.00$ LFCulvert, CMP, 72"D-41350.00$ LFCulvert, Concrete, 8"D-4242.00$ LFCulvert, Concrete, 12"D-4348.00$ LFCulvert, Concrete, 15"D-4478.00$ LFCulvert, Concrete, 18"D-4548.00$ LFCulvert, Concrete, 24"D-4678.00$ LFCulvert, Concrete, 30"D-47125.00$ LFCulvert, Concrete, 36"D-48150.00$ LFCulvert, Concrete, 42"D-49175.00$ LFCulvert, Concrete, 48"D-50205.00$ LFCulvert, CPE Triple Wall, 6" D-5114.00$ LFCulvert, CPE Triple Wall, 8" D-5216.00$ LFCulvert, CPE Triple Wall, 12" D-5324.00$ LFCulvert, CPE Triple Wall, 15" D-5435.00$ LFCulvert, CPE Triple Wall, 18" D-5541.00$ LFCulvert, CPE Triple Wall, 24" D-5656.00$ LFCulvert, CPE Triple Wall, 30" D-5778.00$ LFCulvert, CPE Triple Wall, 36" D-58130.00$ LFCulvert, LCPE, 6"D-5960.00$ LFCulvert, LCPE, 8"D-6072.00$ LF1087,776.00Culvert, LCPE, 12"D-6184.00$ LF342,856.00Culvert, LCPE, 15"D-6296.00$ LFCulvert, LCPE, 18"D-63108.00$ LFCulvert, LCPE, 24"D-64120.00$ LFCulvert, LCPE, 30"D-65132.00$ LFCulvert, LCPE, 36"D-66144.00$ LFCulvert, LCPE, 48"D-67156.00$ LFCulvert, LCPE, 54"D-68168.00$ LFSUBTOTAL THIS PAGE:10,632.00(B)(C)(D)(E)Page 8 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, LCPE, 60"D-69180.00$ LFCulvert, LCPE, 72"D-70192.00$ LFCulvert, HDPE, 6"D-7142.00$ LFCulvert, HDPE, 8"D-7242.00$ LFCulvert, HDPE, 12"D-7374.00$ LFCulvert, HDPE, 15"D-74106.00$ LFCulvert, HDPE, 18"D-75138.00$ LFCulvert, HDPE, 24"D-76221.00$ LFCulvert, HDPE, 30"D-77276.00$ LFCulvert, HDPE, 36"D-78331.00$ LFCulvert, HDPE, 48"D-79386.00$ LFCulvert, HDPE, 54"D-80441.00$ LFCulvert, HDPE, 60"D-81496.00$ LFCulvert, HDPE, 72"D-82551.00$ LFPipe, Polypropylene, 6"D-8384.00$ LFPipe, Polypropylene, 8"D-8489.00$ LFPipe, Polypropylene, 12"D-8595.00$ LFPipe, Polypropylene, 15"D-86100.00$ LFPipe, Polypropylene, 18"D-87106.00$ LFPipe, Polypropylene, 24"D-88111.00$ LFPipe, Polypropylene, 30"D-89119.00$ LFPipe, Polypropylene, 36"D-90154.00$ LFPipe, Polypropylene, 48"D-91226.00$ LFPipe, Polypropylene, 54"D-92332.00$ LFPipe, Polypropylene, 60"D-93439.00$ LFPipe, Polypropylene, 72"D-94545.00$ LFCulvert, DI, 6"D-9561.00$ LFCulvert, DI, 8"D-9684.00$ LFCulvert, DI, 12"D-97106.00$ LFCulvert, DI, 15"D-98129.00$ LFCulvert, DI, 18"D-99152.00$ LFCulvert, DI, 24"D-100175.00$ LFCulvert, DI, 30"D-101198.00$ LFCulvert, DI, 36"D-102220.00$ LFCulvert, DI, 48"D-103243.00$ LFCulvert, DI, 54"D-104266.00$ LFCulvert, DI, 60"D-105289.00$ LFCulvert, DI, 72"D-106311.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 9 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESSpecialty Drainage ItemsDitching SD-19.50$ CYFlow Dispersal Trench (1,436 base+)SD-328.00$ LF French Drain (3' depth)SD-426.00$ LFGeotextile, laid in trench, polypropyleneSD-53.00$ SYMid-tank Access Riser, 48" dia, 6' deepSD-62,000.00$ EachPond Overflow SpillwaySD-716.00$ SYRestrictor/Oil Separator, 12"SD-81,150.00$ EachRestrictor/Oil Separator, 15"SD-91,350.00$ EachRestrictor/Oil Separator, 18"SD-101,700.00$ EachRiprap, placedSD-1142.00$ CYTank End Reducer (36" diameter)SD-121,200.00$ EachInfiltration pond testingSD-13125.00$ HRPermeable PavementSD-14Permeable Concrete SidewalkSD-15Culvert, Box __ ft x __ ftSD-16SUBTOTAL SPECIALTY DRAINAGE ITEMS:(B)(C)(D)(E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention PondSF-1Each Detention TankSF-2Each Detention VaultSF-3Each Infiltration PondSF-4Each Infiltration TankSF-5Each Infiltration VaultSF-6Each Infiltration TrenchesSF-7Each Basic Biofiltration SwaleSF-8Each Wet Biofiltration SwaleSF-9Each WetpondSF-10Each WetvaultSF-11Each Sand FilterSF-12Each Sand Filter VaultSF-13Each Linear Sand FilterSF-14Each Proprietary FacilitySF-15Each Bioretention FacilitySF-16Each SUBTOTAL STORMWATER FACILITIES:(B)(C)(D)(E)Page 10 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESWRITE-IN-ITEMS (INCLUDE ON-SITE BMPs)Filterra® WI-115,000.00$ 230,000.00WI-2WI-3WI-4WI-5WI-6WI-7WI-8WI-9WI-10WI-11WI-12WI-13WI-14WI-15SUBTOTAL WRITE-IN ITEMS:30,000.00DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:42,132.00SALES TAX @ 10%4,213.20DRAINAGE AND STORMWATER FACILITIES TOTAL:46,345.20(B) (C) (D) (E)Page 11 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostConnection to Existing WatermainW-12,000.00$ EachDuctile Iron Watermain, CL 52, 4 Inch DiameterW-250.00$ LFDuctile Iron Watermain, CL 52, 6 Inch DiameterW-356.00$ LFDuctile Iron Watermain, CL 52, 8 Inch DiameterW-460.00$ LFDuctile Iron Watermain, CL 52, 10 Inch DiameterW-570.00$ LFDuctile Iron Watermain, CL 52, 12 Inch DiameterW-680.00$ LFGate Valve, 4 inch DiameterW-7500.00$ EachGate Valve, 6 inch DiameterW-8700.00$ EachGate Valve, 8 Inch DiameterW-9800.00$ EachGate Valve, 10 Inch DiameterW-101,000.00$ EachGate Valve, 12 Inch DiameterW-111,200.00$ EachFire Hydrant AssemblyW-124,000.00$ EachPermanent Blow-Off AssemblyW-131,800.00$ EachAir-Vac Assembly, 2-Inch DiameterW-142,000.00$ EachAir-Vac Assembly, 1-Inch DiameterW-151,500.00$ EachCompound Meter Assembly 3-inch DiameterW-168,000.00$ EachCompound Meter Assembly 4-inch DiameterW-179,000.00$ EachCompound Meter Assembly 6-inch DiameterW-1810,000.00$ EachPressure Reducing Valve Station 8-inch to 10-inchW-1920,000.00$ EachWATER SUBTOTAL:SALES TAX @ 10%WATER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B)(C)Page 12 of 14Ref 8-H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostClean OutsSS-11,000.00$ EachGrease Interceptor, 500 gallonSS-28,000.00$ EachGrease Interceptor, 1000 gallonSS-310,000.00$ EachGrease Interceptor, 1500 gallonSS-415,000.00$ EachSide Sewer Pipe, PVC. 4 Inch DiameterSS-580.00$ LFSide Sewer Pipe, PVC. 6 Inch DiameterSS-695.00$ LFSewer Pipe, PVC, 8 inch DiameterSS-7105.00$ LFSewer Pipe, PVC, 12 Inch DiameterSS-8120.00$ LFSewer Pipe, DI, 8 inch DiameterSS-9115.00$ LFSewer Pipe, DI, 12 Inch DiameterSS-10130.00$ LFManhole, 48 Inch DiameterSS-116,000.00$ EachManhole, 54 Inch DiameterSS-136,500.00$ EachManhole, 60 Inch DiameterSS-157,500.00$ EachManhole, 72 Inch DiameterSS-178,500.00$ EachManhole, 96 Inch DiameterSS-1914,000.00$ EachPipe, C-900, 12 Inch DiameterSS-21180.00$ LFOutside DropSS-241,500.00$ LSInside DropSS-251,000.00$ LSSewer Pipe, PVC, ____ Inch DiameterSS-26Lift Station (Entire System)SS-27LSSANITARY SEWER SUBTOTAL:SALES TAX @ 10%SANITARY SEWER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B)(C)Page 13 of 14Ref 8-H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200Date:Name:Project Name: PE Registration No:CED Plan # (LUA):Firm Name:CED Permit # (U):Firm Address:Site Address:Phone No.Parcel #(s):Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a)Existing Right-of-Way Improvements Subtotal (b)(b)3,618.18$ Future Public Improvements Subtotal(c)-$ Stormwater & Drainage Facilities (Public & Private) Subtotal(d)(d)46,345.20$ (e)(f)Site RestorationCivil Construction PermitMaintenance Bond9,992.68$ Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. EST1((b) + (c) + (d)) x 20%-$ MAINTENANCE BOND */**(after final acceptance of construction)14,658.60$ 3,618.18$ 51,772.46$ 14,658.60$ -$ 46,345.20$ -$ 66,431.06$ P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS5/10/2018Kathy Hargrave30794Sitts & Hill EngineersR((b x 150%) + (d x 100%))S(e) x 150% + (f) x 100%Bond Reduction: Existing Right-of-Way Improvements (Quantity Remaining)2Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2T(P +R - S)Prepared by:Project InformationCONSTRUCTION BOND AMOUNT */**(prior to permit issuance)(253) 474-9449kathyh@sittshill.comRenton Parking Lot##-######620 SW 12th St, Renton, WA 980573340404805FOR APPROVAL########4815 Center Street, Tacoma, WA 98409Page 14 of 14Ref 8-H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/30/2018 WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON A.3 Stormwater Engineering Calculations Flow Control Predeveloped Conditions: **Please note that the existing gravel conditions onsite were modeled as driveways in WWHM. ** WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON Mitigated WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON Flow Frequency Results The flow frequency table outlined below indicates that the site decreases the predeveloped flowrate. Therefore decreasing the site’s tributary flowrate to the existing catch basin located within the alley. TPN 3340404805 S.W. 12TH S T . NORTH GRADING AND DRAINAGE PLAN LEGEND PROPOSED FEATURES- GENERAL NOTES KEY NOTES R Call 811 two business days before you dig ALLEY S.W. 12TH ST R E E T GRADING AND DRAINAGE PLAN IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN WSADA PARKING LOT A-NNNNNNN PHONE: (253) 474-9449 | FAX: (253) 474-0153 4815 CENTER STREET | TACOMA, WA. 98409 SITTS & HILL ENGINEERS, INC. CIVIL STRUCTURAL SURVEYING http://www.sittshill.com/ WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON Water Quality Predeveloped Conditions: WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON Mitigated Conditions: WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON Filterra® Unit Sizing: TPN 3340404805 S.W. 12TH S T . NORTH GRADING AND DRAINAGE PLAN LEGEND PROPOSED FEATURES- GENERAL NOTES KEY NOTES R Call 811 two business days before you dig ALLEY S.W. 12TH ST R E E T GRADING AND DRAINAGE PLAN IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN WSADA PARKING LOT A-NNNNNNN PHONE: (253) 474-9449 | FAX: (253) 474-0153 4815 CENTER STREET | TACOMA, WA. 98409 SITTS & HILL ENGINEERS, INC. CIVIL STRUCTURAL SURVEYING http://www.sittshill.com/ WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON WSADA PARKING LOT TECHNICAL INFORMATION REPORT SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON A.4 Geotechnical Engineering Report Geotechnical Engineering Report Washington State Auto Dealers Association 621 SW Grady Way Renton, Washington 98057 May 18, 2018 prepared for: Sitts & Hill Engineers, Inc. Attention: Kathy Hargrave 4815 Center Street Tacoma, Washington 98409 prepared by: Migizi Group, Inc. PO Box 44840 Tacoma, Washington 98448 (253) 537-9400 MGI Project P1258-T18 i TABLE OF CONTENTS Page No. 1.0 SITE AND PROJECT DESCRIPTION............................................................................................... 1 2.0 EXPLORATORY METHODS ............................................................................................................. 2 2.1 Test Pit Procedures ................................................................................................................ 2 3.0 SITE CONDITIONS ............................................................................................................................ 3 3.1 Surface Conditions ................................................................................................................. 3 3.2 Soil Conditions ....................................................................................................................... 3 3.3 Groundwater Conditions ...................................................................................................... 3 3.4 Seismic Conditions ................................................................................................................. 4 3.5 Liquefaction Potential ............................................................................................................ 4 4.0 CONCLUSIONS AND RECOMMENDATIONS ............................................................................ 4 4.1 Site Preparation ...................................................................................................................... 5 4.2 Asphalt Pavement .................................................................................................................. 7 4.3 Structural Fill .......................................................................................................................... 8 5.0 RECOMMENDED ADDITIONAL SERVICES ................................................................................ 9 6.0 CLOSURE ........................................................................................................................................... 10 List of Tables Table 1. Approximate Locations and Depths of Explorations ............................................................................. 2 List of Figures Figure 1. Topographic and Location Map Figure 2. Site and Exploration Plan APPENDIX A Soil Classification Chart and Key to Test Data .................................................................................................. A-1 Logs of Test Pits TP-1 through TP-3 .......................................................................................................... A-2…A-4 Page 1 of 10 MIGIZI GROUP, INC. PO Box 44840 PHONE (253) 537-9400 Tacoma, Washington 98448 FAX (253) 537-9401 May 18, 2018 Sitts & Hill Engineers, Inc. 4815 Center Street Tacoma, Washington 98409 Attention: Kathy Hargrave Subject: Geotechnical Engineering Report Washington State Auto Dealers Association 621 SW Grady Way Renton, Washington 98057 MGI Project P1258-T18 Dear Ms. Hargrave: Migizi Group, Inc. (MGI) is pleased to submit this report describing the results of our geotechnical engineering evaluation for a proposed asphalt parking lot expansion to be located in a vacant lot immediately south of the existing parking lot for the Washington State Auto Dealers Association (WSADA) building in Renton, Washington. A previous Geotechnical Letter Report was prepared for the existing facilities by E3RA, Inc. dated April 4, 2012. This report has been prepared for the exclusive use of Sitts & Hill Engineers, Inc., and their consultants, for specific application to this project, in accordance with generally accepted geotechnical engineering practice. 1.0 SITE AND PROJECT DESCRIPTION The project site is located along the south side of SW Grady Way in a commercial area just north of I-405 in Renton, Washington, as shown on the enclosed Topographic and Location Map (Figure 1). The project area is rectangularly-shaped, encompassing a total area of 0.33-acres. The site is undeveloped and lies in the ancestral floodplain of the Black and Green Rivers before the partial draining of Lake Washington in 1916. The site is bordered by SW 12th St to the south, asphalt parking lots to the north and east, and Bell Electronics to the west. It is our understanding that the project area will be stripped, paved, and connected to the existing WSADA parking area to the north. The new parking lot will be at or near existing grade. Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 2 of 10 2.0 EXPLORATORY METHODS We explored surface and subsurface conditions at the project site on April 27, 2018. Our exploration and evaluation program comprised the following elements: • Surface reconnaissance of the site; • Three test pit explorations (designated TP-1, TP-2, and TP-3) advanced on April 27, 2018; and • A review of published geologic and seismologic maps and literature. Table 1 summarizes the approximate functional locations and termination depths of our subsurface explorations, and Figure 2 depicts their approximate relative locations. The following sections describe the procedures used for excavation of the test pits. TABLE 1 APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS Exploration Functional Location Termination Depth (feet) TP-1 TP-2 TP-3 Roughly central to the western third of the property Roughly the middle-most point of the property Roughly central to the eastern third of the property 10 3 10 The specific numbers and locations of our explorations were selected in relation to the existing site features, under the constraints of surface access, underground utility conflicts, and budget considerations. It should be realized that the explorations performed and utilized for this evaluation reveal subsurface conditions only at discrete locations across the project site and that actual conditions in other areas could vary. Furthermore, the nature and extent of any such variations would not become evident until additional explorations are performed or until construction activities have begun. If significant variations are observed at that time, we may need to modify our conclusions and recommendations contained in this report to reflect the actual site conditions. 2.1 Test Pit Procedures Our exploratory test pits were excavated with a rubber-tracked mini-excavator operated by an excavation contractor under subcontract to MGI. An engineering geologist from our firm observed the test pit excavations, collected soil samples, and logged the subsurface conditions. The enclosed test pit logs indicate the vertical sequence of soils and materials encountered in our test pits, based on our field classifications. Where a soil contact was observed to be gradational or undulating, our logs indicate the average contact depth. We estimated the relative density and consistency of the in-situ soils by means of the excavation characteristics and the stability of the test pit sidewalls. Our logs also indicate the approximate depths of any sidewall caving or groundwater seepage observed in the test pits. The soils were classified visually in general accordance with the system described in Figure A-1, which includes a key to the exploration logs. Summary logs of our explorations are included as Figure A-2 through A-4. Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 3 of 10 3.0 SITE CONDITIONS The following sections present our observations, measurements, findings, and interpretations regarding surface, soil, groundwater, and infiltration conditions. 3.1 Surface Conditions As previously indicated, the project site consists of a rectangularly-shaped, 0.33-acre commercial property situated near the intersection of I-405 and WA-167 in Renton. The property lies in the ancestral floodplain of the Black and Green Rivers before the partial draining of Lake Washington in 1916. The site is undeveloped and topographically flat, with the exception of a dry, empty pit in the southeastern corner of the property approximately 4 feet deep and 20 feet in length. Site vegetation is limited to sparse grass and spiky bushes lining the edges of the property, in addition to a line of deciduous and evergreen trees on the eastern boundary near an existing parking lot. No hydrologic features were observed on site, such as seeps, springs, ponds and streams. 3.2 Soil Conditions We observed subgrade conditions in three test pits across the property. These explorations revealed structural fill and construction-related debris such as concrete, asphalt, and brick in a dense condition down to approximately 2½ to 4½ feet below the surface. This material overlies dense native alluvial flood plain deposits comprised of fine sand, silty sand, silt and gravel. Native soils were all poorly consolidated and oversaturated. While excavating TP-2, a block of concrete prevented further excavation beyond 3 feet deep and the test pit was terminated. In the Geologic Map of the Renton Quadrangle, King County, Washington, as prepared by the Department of the Interior United States Geological Survey (USGS) (1965), the project site is mapped as containing Qaw, or Quaternary Alluvium associated with the flood plains of the White and Green Rivers. The upper part of these deposits are mostly clayey silt and fine sand, locally peaty, being 10 to 20 feet thick near Kent, thickening to 30 to 40 feet near Tukwila. The lower part of these deposits are mostly medium and coarse sand and can reach thicknesses of up to 75 feet. The National Cooperative Soil Survey (NCSS) for the King County Area classifies soils onsite as Ur-Urban Land, surrounded by minor soil units of sand and silt loam. This soil series reportedly formed along alluvial flood plains and is comprised of sandy loam, silt loam, silty clay loam and sand. Our subsurface explorations generally correspond with the site classifications prepared by the USGS and NCSS. The enclosed exploration logs (Appendix A) provide a detailed description of the soil strata encountered in our subsurface explorations. 3.3 Groundwater Conditions We encountered groundwater seepage in two of our three subsurface explorations, at a depth of 4 to 4½ feet below existing grade. Given the fact that our explorations were performed just outside of Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 4 of 10 what is generally considered the rainy season (November 1 to March 31), we do not anticipate that groundwater will rise much higher than that which we observed. Groundwater levels will fluctuate with localized geology and precipitation. 3.4 Seismic Conditions Based on our analysis of subsurface exploration logs and our review of published geologic maps, we interpret the onsite soil conditions to generally correspond with site class E, as defined by Table 30.2-1 in ASCE 7, per the 2015 International Building Code (IBC). Using 2015 IBC information on the USGS Design Summary Report website, Risk Category I/II/III seismic parameters for the site are as follows: Ss = 1.442 g SMS = 1.298 g SDS = 0.865 g S1 = 0.538 g SM1 = 1.292 g SD1 = 0.862 g Using the 2015 IBC information, MCER Response Spectrum Graph on the USGS Design Summary Report website, Risk Category I/II/III, Sa at a period of 0.2 seconds is 1.30 g and Sa at a period of 1.0 seconds is 1.30 g. The Design Response Spectrum Graph from the same website, using the same IBC information and Risk Category, Sa at a period of 0.2 seconds is 0.86 g and Sa at a period of 1.0 seconds is 0.86 g. 3.5 Liquefaction Potential Liquefaction is a sudden increase in pore water pressure and a sudden loss of soil shear strength caused by shear strains, as could result from an earthquake. Research has shown that saturated, loose, fine to medium sands with a fines (silt and clay) content less than about 20 percent are most susceptible to liquefaction. Poorly consolidated soils encountered below the water table (a depth of 4 to 4½ feet) present a moderate to severe risk for soil liquefaction. Recommendations for pavement section design and construction contained within this report helps mitigate some of this risk, but the risk for soil liquefaction and resultant post-construction settlement should still be considered moderate across the project area in the instance of a large-scale seismic event. 4.0 CONCLUSIONS AND RECOMMENDATIONS It is our understanding that the project area will be stripped, paved, and connected to the existing WSADA parking area to the north. The new parking lot will be at or near existing grade. We offer these recommendations: • Feasibility: Based on our field explorations, research, and evaluations, the proposed pavements appear feasible from a geotechnical standpoint. • Pavement Sections: We recommend a conventional pavement section comprised of an asphalt concrete pavement over a crushed rock base course over a properly prepared (compacted) subgrade or a granular subbase. Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 5 of 10 All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling operation should be over excavated to an additional maximum depth of 12 inches and replaced with a suitable structural fill material. The following sections of this report present our specific geotechnical conclusions and recommendations concerning site preparation, spread footings, slab-on-grade floors, asphalt pavement, and structural fill. The Washington State Department of Transportation (WSDOT) Standard Specifications and Standard Plans cited herein refer to WSDOT publications M41-10, Standard Specifications for Road, Bridge, and Municipal Construction, and M21-01, Standard Plans for Road, Bridge, and Municipal Construction, respectively. 4.1 Site Preparation Preparation of the project site should involve erosion control, temporary drainage, clearing, stripping, excavations, cutting, subgrade compaction, and filling. Erosion Control: Before new construction begins, an appropriate erosion control system should be installed. This system should collect and filter all surface water runoff through silt fencing. We anticipate a system of berms and drainage ditches around construction areas will provide an adequate collection system. Silt fencing fabric should meet the requirements of WSDOT Standard Specification 9-33.2 Table 3. In addition, silt fencing should embed a minimum of 6 inches below existing grade. An erosion control system requires occasional observation and maintenance. Specifically, holes in the filter and areas where the filter has shifted above ground surface should be replaced or repaired as soon as they are identified. Temporary Drainage: We recommend intercepting and diverting any potential sources of surface or near-surface water within the construction zones before stripping begins. Because the selection of an appropriate drainage system will depend on the water quantity, season, weather conditions, construction sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the time of construction. Based on our current understanding of the construction plans, surface and subsurface conditions, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept surface water runoff. Clearing and Stripping: After surface and near-surface water sources have been controlled, sod, topsoil, and root-rich soil should be stripped from the site. The proposed work area is currently paved and no stripping will be necessary. Site Excavations: Based on our explorations, we expect that excavations will encounter loose/soft to medium dense/stiff silty, sandy alluvial soils which can be easily excavated using standard excavation equipment. Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 6 of 10 Dewatering: We encountered groundwater seepage in two of three of our explorations at a depth of 4 to 4½ feet below existing grade. Given the fact that our explorations were performed just outside of what is generally considered the rainy season (November 1 to March 31), we do not anticipate that groundwater will rise much higher than that which we observed. If groundwater is encountered in shallower excavations, we anticipate that an internal system of ditches, sumpholes, and pumps will be adequate to temporarily dewater most excavations. For deeper excavations well below the water table, expensive dewatering equipment, such as well points, may need to be utilized in order to adequately dewater excavations. Temporary Cut Slopes: All temporary soil slopes associated with site cutting or excavations should be adequately inclined to prevent sloughing and collapse. Temporary cut slopes in site soils should be no steeper than 1½H:1V, and should conform to Washington Industrial Safety and Health Act (WISHA) regulations. Subgrade Compaction: Exposed subgrades for the foundations of the planned additions should be compacted to a firm, unyielding state before new concrete or fill soils are placed. Any localized zones of looser granular soils observed within a subgrade should be compacted to a density commensurate with the surrounding soils. In contrast, any organic, soft, or pumping soils observed within a subgrade should be overexcavated and replaced with a suitable structural fill material. Site Filling: Our conclusions regarding the reuse of onsite soils and our comments regarding wet- weather filling are presented subsequently. Regardless of soil type, all fill should be placed and compacted according to our recommendations presented in the Structural Fill section of this report. Specifically, building pad fill soil should be compacted to a uniform density of at least 95 percent (based on ASTM:D-1557). Onsite Soils: We offer the following evaluation of these onsite soils in relation to potential use as structural fill: • Fill: The fill that overlies the site contains construction debris and some organic material, so is not reusable as structural fill. If areas of debris and organic-free fill are encountered during the construction process and are thought to be reusable, we recommend that MGI evaluate their potential for reuse. • Alluvial Silt and Silty Sand: The alluvial silty sand that underlies the site is very moisture sensitive and will be difficult or impossible to reuse during most weather conditions. The majority of this soil type is currently above the optimum moisture content and will not compact adequately unless extensively aerated. • Alluvial Fine to Medium Sand with Gravel: Where encountered, and if properly segregated from its siltier counterpart, the clean native fine sands are a possible source of structural fill. This material type is relatively impervious to moisture content variations and can be reused in most weather conditions. Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 7 of 10 Permanent Slopes: All permanent cut slopes and fill slopes should be adequately inclined to reduce long-term raveling, sloughing, and erosion. We generally recommend that no permanent slopes be steeper than 2H:1V. For all soil types, the use of flatter slopes (such as 2½H:1V) would further reduce long-term erosion and facilitate revegetation. Slope Protection: We recommend that a permanent berm, swale, or curb be constructed along the top edge of all permanent slopes to intercept surface flow. Also, a hardy vegetative groundcover should be established as soon as feasible, to further protect the slopes from runoff water erosion. Alternatively, permanent slopes could be armored with quarry spalls or a geosynthetic erosion mat. 4.2 Asphalt Pavement Since asphalt pavements will be used across much of the project site, we offer the following comments and recommendations for pavement design and construction. Subgrade Preparation: We recommend a conventional pavement section comprised of an asphalt concrete pavement over a crushed rock base course over a properly prepared (compacted) subgrade or a granular subbase. All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling operation should be over excavated to an additional maximum depth of 12 inches and replaced with a suitable structural fill material. All structural fill should be compacted according to our recommendations given in the Structural Fill section. Specifically, the upper 2 feet of soils underlying pavement section should be compacted to at least 95 percent (based on ASTM D-1557), and all soils below 2 feet should be compacted to at least 90 percent. Pavement Materials: For the base course, we recommend using imported crushed rock, such as "Crushed Surfacing Top Course” per WSDOT Standard Specification 9-03.9(3). If a subbase course is needed, we recommend using imported, clean, well-graded sand and gravel such as “Ballast” or “Gravel Borrow” per WSDOT Standard Specifications 9-03.9(1) and 9-03.14, respectively. Conventional Asphalt Sections: A conventional pavement section typically comprises an asphalt concrete pavement over a crushed rock base course. We recommend using the following conventional pavement sections: Minimum Thickness Section Automobile Parking Areas Driveways and Areas Subject to Truck Traffic Asphalt Concrete Pavement 2 inches 3 inches Crushed Rock Base 4 inches 6 inches Compaction and Observation: All subbase and base course material should be compacted to at least 95 percent of the Modified Proctor maximum dry density (ASTM D-1557), and all asphalt concrete should be compacted to at least 92 percent of the Rice value (ASTM D-2041). We recommend that an MGI representative be retained to observe the compaction of each course before any overlying Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 8 of 10 layer is placed. For the subbase and pavement course, compaction is best observed by means of frequent density testing. For the base course, methodology observations and hand-probing are more appropriate than density testing. Pavement Life and Maintenance: No asphalt pavement is maintenance-free. The above described pavement sections present our minimum recommendations for an average level of performance during a 20-year design life, therefore, an average level of maintenance will likely be required. Furthermore, a 20-year pavement life typically assumes that an overlay will be placed after about 10 years. Thicker asphalt and/or thicker base and subbase courses would offer better long-term performance but would cost more initially; thinner courses would be more susceptible to “alligator” cracking and other failure modes. As such, pavement design can be considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and higher maintenance costs. 4.3 Structural Fill The term "structural fill" refers to any material placed under foundations, retaining walls, slab-on- grade floors, sidewalks, pavements, and other structures. Our comments, conclusions, and recommendations concerning structural fill are presented in the following paragraphs. Materials: Typical structural fill materials include clean sand, gravel, pea gravel, washed rock, crushed rock, well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit- run"), and miscellaneous mixtures of silt, sand, and gravel. Recycled asphalt, concrete, and glass, which are derived from pulverizing the parent materials, are also potentially useful as structural fill in certain applications. Soils used for structural fill should not contain any organic matter or debris, nor any individual particles greater than about 6 inches in diameter. Fill Placement: Clean sand, gravel, crushed rock, soil mixtures, and recycled materials should be placed in horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be thoroughly compacted with a mechanical compactor. Compaction Criteria: Using the Modified Proctor test (ASTM:D-1557) as a standard, we recommend that structural fill used for various onsite applications be compacted to the following minimum densities: Fill Application Minimum Compaction Asphalt pavement base Asphalt pavement subgrade (upper 2 feet) Asphalt pavement subgrade (below 2 feet) 95 percent 95 percent 90 percent Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018 Geotechnical Engineering Report P1258-T18 Migizi Group, Inc. Page 9 of 10 Subgrade Observation and Compaction Testing: Regardless of material or location, all structural fill should be placed over firm, unyielding subgrades prepared in accordance with the Site Preparation section of this report. The condition of all subgrades should be observed by geotechnical personnel before filling or construction begins. Also, fill soil compaction should be verified by means of in-place density tests performed during fill placement so that adequacy of soil compaction efforts may be evaluated as earthwork progresses. Soil Moisture Considerations: The suitability of soils used for structural fill depends primarily on their grain-size distribution and moisture content when they are placed. As the "fines" content (that soil fraction passing the U.S. No. 200 Sieve) increases, soils become more sensitive to small changes in moisture content. Soils containing more than about 5 percent fines (by weight) cannot be consistently compacted to a firm, unyielding condition when the moisture content is more than 2 percentage points above or below optimum. For fill placement during wet-weather site work, we recommend using "clean" fill, which refers to soils that have a fines content of 5 percent or less (by weight) based on the soil fraction passing the U.S. No. 4 Sieve. 5.0 RECOMMENDED ADDITIONAL SERVICES Because the future performance and integrity of the structural elements will depend largely on proper site preparation, drainage, fill placement, and construction procedures, monitoring and testing by experienced geotechnical personnel should be considered an integral part of the construction process. Subsequently, we recommend that MGI be retained to provide the following post-report services: • Review all construction plans and specifications to verify that our design criteria presented in this report have been properly integrated into the design; • Prepare a letter summarizing all review comments (if required); • Check all completed subgrades for footings and slab-on-grade floors before concrete is poured, in order to verify their bearing capacity; and • Prepare a post-construction letter summarizing all field observations, inspections, and test results (if required). APPROXIMATE SITE LOCATION P.O. Box 44840 Tacoma, WA 98448 Location Job Number Figure DateTitle 621 SW Grady Way Renton, Washington Topographic and Location Map 1 05/16/18 P1258-T18 APPENDIX A SOIL CLASSIFICATION CHART AND KEY TO TEST DATA LOGS OF TEST PITS CLAYEY GRAVELS, POORLY GRADED GRAVEL-SAND-CLAY MIXTURES SILTS AND CLAYSCOARSE GRAINED SOILSMore than Half > #200 sieveLIQUID LIMIT LESS THAN 50 LIQUID LIMIT GREATER THAN 50 CLEAN GRAVELS WITH LITTLE OR NO FINES GRAVELS WITH OVER 15% FINES CLEAN SANDS WITH LITTLE OR NO FINES MORE THAN HALF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE MORE THAN HALF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE INORGANIC SILTS, MICACEOUS OR DIATOMACIOUS FINE SANDY OR SILTY SOILS, ELASTIC SILTS ORGANIC CLAYS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY OH INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS, OR CLAYEY SILTS WITH SLIGHT PLASTICITY CH SILTY GRAVELS, POORLY GRADED GRAVEL-SAND-SILT MIXTURES SANDS SILTS AND CLAYS Figure A-1 INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS R-Value Sieve Analysis Swell Test Cyclic Triaxial Unconsolidated Undrained Triaxial Torvane Shear Unconfined Compression (Shear Strength, ksf) Wash Analysis (with % Passing No. 200 Sieve) Water Level at Time of Drilling Water Level after Drilling(with date measured) RV SA SW TC TX TV UC (1.2) WA (20) Modified California Split Spoon Pushed Shelby Tube Auger Cuttings Grab Sample Sample Attempt with No Recovery Chemical Analysis Consolidation Compaction Direct Shear Permeability Pocket Penetrometer CA CN CP DS PM PP PtHIGHLY ORGANIC SOILS TYPICAL NAMES GRAVELS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES MAJOR DIVISIONS PEAT AND OTHER HIGHLY ORGANIC SOILS WELL GRADED SANDS, GRAVELLY SANDS POORLY GRADED SANDS, GRAVELLY SANDS SILTY SANDS, POORLY GRADED SAND-SILT MIXTURES CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES POORLY GRADED GRAVELS, GRAVEL-SAND MIXTURES SOIL CLASSIFICATION CHART AND KEY TO TEST DATA GW GP GM GC SW SP SM SC ML FINE GRAINED SOILSMore than Half < #200 sieveLGD A NNNN02 GINT US LAB.GPJ 11/4/05INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS CL OL MH SANDS WITH OVER 15% FINES GB S-1 GP- GM SM SP ML 0.5 2.5 4.0 10.0 (GP-GM) Gray/brown gravel with silt and sand (dense, moist) (Fill) (SM) Gray silty sand with gravel and concrete/asphalt/brick debris (dense, moist) (Fill) (SP) Blue/gray fine to medium sand with gravel (medium dense, moist) (Alluvium) (ML) Blue/gray silt (very soft, wet) (Alluvium) Moderate caving observed from 4 to 10 feet Moderate groundwater seepage observed at 4 feet The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot. Bottom of test pit at 10.0 feet. NOTES LOGGED BY ZLL EXCAVATION METHOD Rubber Tracked Mini Excavator EXCAVATION CONTRACTOR Paulman GROUND WATER LEVELS: CHECKED BY JEB DATE STARTED 4/27/18 COMPLETED 4/27/18 AT TIME OF EXCAVATION 4.00 ft Moderate seepage AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZEGROUND ELEVATION SAMPLE TYPENUMBERDEPTH(ft)0.0 2.5 5.0 7.5 10.0 PAGE 1 OF 1 Figure A-2 TEST PIT NUMBER TP-1 CLIENT Sitts & Hill Engineers, Inc. PROJECT NUMBER P1258-T18 PROJECT NAME Washington State Auto Dealers Association PROJECT LOCATION 621 SW Grady Way, Renton, WA COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 5/16/18 11:29 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1258-T18\P1258-T18 TEST PITS.GPJMigizi Group, Inc. PO Box 44840 Tacoma, WA 98448 Telephone: 253-537-9400 Fax: 253-537-9401 U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION GP- GM SM 0.8 3.0 (GP-GM) Gray/brown gravel with silt and sand (dense, moist) (Fill) (SM) Gray silty sand with gravel and concrete/asphalt/brick debris (dense, moist) (Fill) Refusal at a depth of 3 feet atop a large section of concrete No caving observed No groundwater seepage observed The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot. Bottom of test pit at 3.0 feet. NOTES LOGGED BY ZLL EXCAVATION METHOD Rubber Tracked Mini Excavator EXCAVATION CONTRACTOR Paulman GROUND WATER LEVELS: CHECKED BY JEB DATE STARTED 4/27/18 COMPLETED 4/27/18 AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZEGROUND ELEVATION SAMPLE TYPENUMBERDEPTH(ft)0.0 2.5 PAGE 1 OF 1 Figure A-3 TEST PIT NUMBER TP-2 CLIENT Sitts & Hill Engineers, Inc. PROJECT NUMBER P1258-T18 PROJECT NAME Washington State Auto Dealers Association PROJECT LOCATION 621 SW Grady Way, Renton, WA COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 5/16/18 11:29 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1258-T18\P1258-T18 TEST PITS.GPJMigizi Group, Inc. PO Box 44840 Tacoma, WA 98448 Telephone: 253-537-9400 Fax: 253-537-9401 U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION GP- GM SM SM ML 1.0 3.5 4.5 10.0 (GP-GM) Gray/brown gravel with silt and sand (dense, moist) (Fill) (SM) Gray silty sand with gravel and concrete/asphalt/brick debris (dense, moist) (Fill) (SM) Gray silty sand with gravel, wood, glass, plastic and other detritus (loose, wet) (Fill) (ML) Blue/gray mottled silt (very soft, wet) (Alluvium) Moderate caving observed from 4.5 to 10 feet Moderate groundwater seepage observed at 4.5 feet The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot. Bottom of test pit at 10.0 feet. NOTES LOGGED BY ZLL EXCAVATION METHOD Rubber Tracked Mini Excavator EXCAVATION CONTRACTOR Paulman GROUND WATER LEVELS: CHECKED BY JEB DATE STARTED 4/27/18 COMPLETED 4/27/18 AT TIME OF EXCAVATION 4.50 ft Moderate seepage AT END OF EXCAVATION --- AFTER EXCAVATION --- TEST PIT SIZEGROUND ELEVATION SAMPLE TYPENUMBERDEPTH(ft)0.0 2.5 5.0 7.5 10.0 PAGE 1 OF 1 Figure A-4 TEST PIT NUMBER TP-3 CLIENT Sitts & Hill Engineers, Inc. PROJECT NUMBER P1258-T18 PROJECT NAME Washington State Auto Dealers Association PROJECT LOCATION 621 SW Grady Way, Renton, WA COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 5/16/18 11:29 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1258-T18\P1258-T18 TEST PITS.GPJMigizi Group, Inc. PO Box 44840 Tacoma, WA 98448 Telephone: 253-537-9400 Fax: 253-537-9401 U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION