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Home My WebLink AboutRS_Drainage_Technical_Information_Report_190607_v1.pdf PRELIMINARY TECHNICAL INFORMATION REPORT FOR KIDDIE RESEARCH DAYCARE CENTER CITY OF RENTON, WASHINGTON Prepared by: Gina R. Brooks, P.E. Date: May 10, 2019 Revised: Core No.: 18227 5/10/2019 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER i KIDDIE RESEARCH DAYCARE CENTER Table of Contents 1. PROJECT OVERVIEW .......................................................................................................................... 1-1 2. CONDITIONS AND REQUIREMENTS SUMMARY ................................................................................ 2-1 2.1 Core Requirements .......................................................................................................................... 2-2 2.1.1 Core Requirement #1: Discharge at the Natural Location ...................................................... 2-2 2.1.2 Core Requirement #2: Offsite Analysis .................................................................................... 2-2 2.1.3 Core Requirement #3: Flow Control......................................................................................... 2-2 2.1.4 Core Requirement #4: Conveyance System ............................................................................. 2-2 2.1.5 Core Requirements #5: Erosion and Sediment Control ........................................................... 2-2 2.1.6 Core Requirement #6: Maintenance and Operations .............................................................. 2-2 2.1.7 Core Requirement #7: Financial Guarantees and Liability ....................................................... 2-2 2.1.8 Core Requirement #8: Water Quality ...................................................................................... 2-4 2.1.9 Core Requirement #9: On-Site BMPs ....................................................................................... 2-5 2.2 Special Requirements ...................................................................................................................... 2-5 2.2.1 Special Requirement #1: Other Adopted Area Specific Requirements .................................... 2-5 2.2.2 Special Requirement #2: Flood Hazard Area Delineation ........................................................ 2-5 2.2.3 Special Requirement #3: Flood Protection Facilities ................................................................ 2-5 2.2.4 Special Requirement #4: Source Control ................................................................................. 2-5 2.2.5 Special Requirement #5: Oil Control ........................................................................................ 2-5 2.2.6 Special Requirement #6: Aquifer Protection Area ................................................................... 2-5 3. OFFSITE ANALYSIS ............................................................................................................................. 3-1 3.1 Resource Review .............................................................................................................................. 3-1 3.1.1 Sensitive Areas ......................................................................................................................... 3-1 3.2 Field Investigation ............................................................................................................................ 3-1 4. FLOW CONTROL AND WATER QUALITY DESIGN ............................................................................... 4-1 4.1 Hydraulic Analysis ............................................................................................................................ 4-1 4.1.1 Existing Conditions ................................................................................................................... 4-4 4.1.2 Developed Conditions .............................................................................................................. 4-7 4.2 Water Quality Treatment Analysis and Design .............................................................................. 4-12 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ................................................................................. 5-1 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER ii 6. SPECIAL REPORTS AND STUDIES ....................................................................................................... 6-1 7. OTHER PERMITS ................................................................................................................................ 7-1 8. ESC ANALYSIS AND DESIGN ............................................................................................................... 8-1 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ............................. 9-1 10. OPERATIONS AND MAINTENANCE .................................................................................................. 10-1 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 1-1 1. PROJECT OVERVIEW The proposed Kiddie Research Daycare Center project is located at 3123 NE Sunset Blvd. Renton, Washington within Section 4, Township 23 North, Range 5 East, W.M. See Vicinity Map below. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 1-2 The site is composed of one parcel (#0423059155) with an area of approximately 0.39 acre. The site is bordered by NE Sunset Blvd. (which is a major arterial) to the west, NE 12th Street (collector) to the south and commercial developed parcels to the east and north. The site was previously developed as a car wash facility. According to City of Renton Soil Map and NRSC Soils Resource Report, site soil type is AmC. Slopes on the site vary from about 3% up to approximately 15%. Topography is generally downhill from east to west. Proposed development of the property will include the construction of a building and parking which will accommodate and house a daycare center. Utilities to support the development will be installed. All existing structures and hard surfaces have been previously demolished and removed based on the field investigation that took place on March 18, 2019. The subject project’s drainage facilities were designed using the guidelines and requirements established in the 2017 City of Renton Surface Water Design Manual (RSWDM). Peak Rate Flow Control Standard (Existing Site Conditions) and Basic Water Quality Treatment are required for this project. No flow control or water quality treatment facilities are proposed as the project is exempt from both flow control and water quality treatment. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 2-1 2. CONDITIONS AND REQUIREMENTS SUMMARY The proposed project is classified as requiring “Full Drainage Review” per the 2017 RSWDM. Therefore, all nine core requirements and six special requirements will be addressed per Section 1.2 and 1.3 of the 2017 RSWDM. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 2-2 2.1 Core Requirements 2.1.1 Core Requirement #1: Discharge at the Natural Location The project discharges its drainage at the natural location which is to the City’s conveyance system located within the intersection of NE Sunset Blvd. and NE 12th Street. 2.1.2 Core Requirement #2: Offsite Analysis See Section 3 of this Report for the downstream analysis. 2.1.3 Core Requirement #3: Flow Control The site falls within the City’s Peak Rate Flow Control Standard (Existing Site Conditions). See City’s Flow Control Application Map on the following pages. This flow control standard requires matching existing conditions for the 2, 10, and 100-year peak rate runoffs. Existing conditions is defined as those that existed prior to May 1979 as determined from aerial photographs and, if necessary, knowledge of individuals familiar with the area, unless a drainage plan for land cover changes has been approved by the City of Renton since May 1979 as part of a City permit or approval (or County-approved permit if in an area that has been annexed by the City). If so, existing site conditions are those created by the site improvements and drainage facilities constructed per the approved drainage plan. Per the preapplication notes for the subject project, there is no existing detention facility on the project site that would provide prior mitigation of currently developed flows. The existing conditions are therefore, those flows generated from the site as it sits today. As demonstrated within Section 4 of this Report, the subject project is exempt from flow control as the developed condition 100-year, 15-minute peak flow does not generate an increase of 0.15 cfs above the existing condition 100-year, 15-minute peak flow. 2.1.4 Core Requirement #4: Conveyance System This core requirement will be addressed during final design. 2.1.5 Core Requirements #5: Erosion and Sediment Control This core requirement will be addressed during final design. 2.1.6 Core Requirement #6: Maintenance and Operations This core requirement will be addressed during final design. 2.1.7 Core Requirement #7: Financial Guarantees and Liability This core requirement will be addressed at the time the permit is issued. Lake Desire Shady Lake (Mud Lake) Panther Lake Lake Youngs Lake Washington B l a c k Ri ve r Gr een Ri v e r Ce darRi verUV900 UV167 UV515 UV169 UV900 UV169 UV167BN IncBN IncBBNNIInnccSSEE RReennttoonn IIssss aa qquuaahh RR dd RReennttoonn MMaappllee VVaalllleeyyRRdd MMaapplleeVVaalllleeyyHHwwyy 110088tthhAAvveeSSEESSWW SSuunnsseettBBllvv dd RRaaiinnii eerrAAvveeNNNE 3rd S t NE 3rd S t SW 43rd StSW 43rd St SS EE CCaarrrrRR dd NE 4th StNE 4th St SSEE RReennttoonn MMaappllee VVaalllleeyy RRddLLooggaannAAvveeNN SR 515SR 515PPaarrkkAAvveeNNOOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNN EE DDuuvvaallllAAvveeNNEEI-405 FWYI-405 FWY II--440055FFWWYYSR 167SR 1671144 00tthh WWaayy SS EENNEE 2277tthh SStt 115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St N 8th StN 8th St PP uuggeettDDrrSSEE RR ee nnttoonnAAvvee SS SSWW 2277tthh SStt BBeennssoonnRRddSSWWiilllliiaammssAAvveeSSMMoonnrrooeeAAvveeNNEESE 128th StSE 128th St II nntt eerr uurr bbaannAA vvee SS HHooqquuiiaammAAvveeNNEE8844tthhAAvveeSSSSEEPPeett rr oovvii tt sskkyyRRddEEVVaalllleeyyHHwwyySE 192nd StSE 192nd St SE 60th StSE 60th St TTaallbboottRRddSSRRee nn tt oo nn AAvveeSS116644tthhAAvveeSSEESE 208th StSE 208th St SE 72nd StSE 72nd St RR aaiinniieerr AA vvee SS 111166tthhAAvveeSSEES 128th StS 128th St NNeewwccaassttllee WWaayy SS 221122tthh SStt SS 118800tthh SStt CCooaall CCrreeeekkPPkkwwyySSEESW 41st StSW 41st St 114400tthhAAvveeSSEE112288tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt NE 12th StNE 12th St BBeeaaccoonn AA vv ee SS FFoorreesstt DDrr SSEE SSEE 116644tthh SStt 114488tthhAAvveeSSEESSEE MMaayy VVaalllleeyy RRdd SS EE JJ oo nn ee ss RR dd SS EE 22 00 44 tthh WW aayySW 34th StSW 34th St SE 144th StSE 144th St 114488tthhAAvveeSSEE115544tthhPPllSSEELL aa kk ee WWaa sshhii nnggtt oonnBBll vvddNNEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEEEMM eerrcceerrWWaayyWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405 ,§-405 ,§-405 μ 012 Miles Flow Control Application Map Reference 1-A Date: 01/09/2014 Flow Control Standards Peak Rate Flow Control Standard (Existing Site Conditions) Flow Control Duration Standard (Existing Site Conditions) Flow Control Duration Standard (Forested Conditions) Flood Problem Flow Unincorporated King County Flow Control Standards Renton City Limits Potential Annexation Area Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 2-4 2.1.8 Core Requirement #8: Water Quality As the City of Renton does not have Sensitive Lake or Sphagnum Bog Water Quality Treatment Areas, Basic Water Quality Treatment is the only other option available. As the proposed project is a commercial development, Enhanced Basic Water Quality Treatment is typically required. However, per RSWDM Section 1.2.8.1.A.Exceptions.3., the required treatment can be reduced to Basic as the downstream conveyance is all tight-lined conveyance with discharge to Lake Washington. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 2-5 As demonstrated within Section 4 of this Report, the subject project is exempt from water quality treatment as site conditions don’t exceed the “Surface Area Exemption” thresholds. 2.1.9 Core Requirement #9: On-Site BMPs See Section 4.1.2 of this Report for discussion on how this Core Requirement is addressed. 2.2 Special Requirements 2.2.1 Special Requirement #1: Other Adopted Area Specific Requirements There are no known additional requirements for the subject project. 2.2.2 Special Requirement #2: Flood Hazard Area Delineation Not applicable since the project does not contain nor is adjacent to a flood hazard area. 2.2.3 Special Requirement #3: Flood Protection Facilities Not applicable since the project does not rely on an existing flood protection facility or plans to modify or construct a new flood protection facility. 2.2.4 Special Requirement #4: Source Control This special requirement will be addressed during final design. 2.2.5 Special Requirement #5: Oil Control Not applicable since the project is not a high use site. The expected average daily traffic is less than 100 vehicles per 1,000 square feet of gross building area. 2.2.6 Special Requirement #6: Aquifer Protection Area Not applicable since the project is not in an Aquifer Protection Area. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 3-1 3. OFFSITE ANALYSIS 3.1 Resource Review The proposed project is located within the Lake Washington Cedar River Watershed. 3.1.1 Sensitive Areas Renton GIS was reviewed for sensitive areas. The proposed project site does not fall within the following sensitive area; coal mines, erosion hazard, flood hazard, floodway, channel migration zone, landslide, seismic hazard, regulated stream, wetland, or wellhead protection. According to the Renton GIS Map, there is a small portion on northeast corner of the site which falls within 15%-25% regulated slope. See picture below. Regulated Slope: 15% to 25% slope area (Per Renton GIS Data) 3.2 Field Investigation A field investigation was completed on March 18, 2019. Upstream Tributary Analysis Based on the field walk and the taken photos, both properties uphill of the proposed project site (one to the north and one to the east) have their own storm drainage facilities. Within their parking lots, active catch basins were found. Therefore, no upstream runoff is considered to enter the project site. See pictures below. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 3-2 Drainage system for the property east of the subject site Drainage system for the property north of the subject site Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 3-3 Downstream Drainage Complaints Drainage complaints were researched within a quarter mile of the project site. City of Renton does not list any current complaints along the project’s downstream route. Onsite Drainage System Description Upon the site visit, all existing catch basins on the site, noted per the topographic boundary survey, were removed except one catch basin which is located on the southwest corner of the project site. Based on field observation, the downstream route for this onsite catch basin could not be determined. Same was true for the catch basin located along the flowline of the curb return of NE Sunset Blvd. and NE 12th Street beyond the southwest corner. As this property previously housed a car wash facility, the onsite catch basins likely discharged to the sanitary sewer though this could not be verified. It was determined though, all of the site’s drainage would ultimately discharge to the City’s conveyance system located within NE Sunset Blvd. Downstream Drainage System Description This downstream route description begins at the catch basin located at the northeast corner of NE Sunset Blvd. and NE 12th Street. This catch basin is located between two islands within the existing crosswalk. As catch basins within the roads were not accessible due to heavy traffic, City resources were utilized to trace the downstream route. Based on City utility maps, the runoff flows through a series of 12”, 24”, and 36” pipes connecting a series of Type I and Type II catch basins until drainage discharges to Lake Washington via the outfall next to the Gene Coulon Memorial Beach Park about 1.1 miles away from the site. See picture below. Downstream Reach Description to a quarter mile Pipe Material Pipe Diameter (in) Overall Pipe Length (ft) Cumulative Length (ft) Concrete 12 104 104 Unknown 12 255 359 Corrugate Metal 24 14 373 Corrugate Metal 36 257 630 Concrete 36 145 775 Corrugated Metal 36 541 1316 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 3-4 Outfall location next to the Gene Coulon Memorial Beach Park 4,652 388 WGS_1984_Web_Mercator_Auxiliary_Sphere City of Renton Print map Template This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATION Notes None Legend 264 0 132 264 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov 03/19/2019 City and County Boundary Parcels Network Structures Inlet Manhole Utility Vault Unknown Structure Control Structures Pump Stations Discharge Points Water Quality Detention Facilities Pond Tank Vault Wetland Stormwater Mains Culverts Open Drains Facility Outlines Fences Streets Points of Interest Parks Waterbodies Map Extent2010 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-1 4. FLOW CONTROL AND WATER QUALITY DESIGN A flow control facility is not proposed as the project is exempt from flow control as delineated below. A water quality treatment facility is not proposed as the project is exempt from water quality treatment as delineated in Section 4.2 of this Report. PEAK RATE FLOW CONTROL EXEMPTION Per the RSWDM Section 1.2.3.1.A. Exceptions, The facility requirement in Peak Rate Flow Control Standard Areas is waived for any threshold discharge area in which the target surfaces subject to this requirement will generate no more than a 0.15-cfs increase (when modeled using 15 minute time steps) in the existing site conditions 100-year peak flow (modeled using same time step unit (e.g., 15-minute) used to calculate the developed flow). Note: for the purposes of this calculation, target surfaces served by on-site BMPs per Appendix C may be modeled in accordance with the on-site BMP sizing credits in Core Requirement #9, Table 1.2.9.A. As shown below, the existing site will produce a 100-year, 15-minute peak flow of 0.363 cfs. The developed site will produce a 100-year, 15-minute peak flow of 0.393 cfs. The difference is these two peak flows is 0.030 cfs which does not exceed the 0.15 cfs requiring flow control. The project therefore, is exempt from flow control. See calculations below. 4.1 Hydraulic Analysis The drainage analysis was modeled using MGSFlood software. Per the City of Renton Soil Survey, the site soil is Alderwood (AmC), hydrologic soil group “C”, Till for modeling. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-2 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-3 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-4 4.1.1 Existing Conditions See Existing Conditions exhibit on the following page. The existing basin boundary area, 0.39 acre, is defined as that area that will be improved through development of the subject project. The existing basin boundary area will include the property area, 0.39 acre, less the right-of-way dedications, 0.10 acre, plus frontage improvements/existing impervious removal extending from the dedicated right-of-way to back of existing curb, 0.10 acre. Existing impervious covers approximately 0.32 acre. The following information was used for generating flow frequencies. See MGS Flood printout below. EXISTING CONDITIONS Total Area = 0.39 acres GROUND COVER AREA (acres) Till-Grass 0.07 Impervious 0.32 MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.46 Program License Number: 200210008 Project Simulation Performed on: 05/06/2019 2:51 PM Report Generation Date: 05/06/2019 2:51 PM ————————————————————————————————— Input File Name: 18227MGSF.fld Project Name: Kiddie Research Daycare Center Analysis Title: Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 15 Full Period of Record Available used for Routing Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961040 Puget East 40 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-5 ---------- Subbasin : Existing Site ---------- -------Area (Acres) -------- Till Grass 0.070 Impervious 0.320 ---------------------------------------------- Subbasin Total 0.390 Predevelopment Runoff Tr (Years) Discharge (cfs) ------------------------------------------- 2-Year 0.125 5-Year 0.160 10-Year 0.189 25-Year 0.250 50-Year 0.296 100-Year 0.363 200-Year 0.371 NE SUNSET BLVDNE 12TH STREET DESIGN E N G I N E E R I N G P L A N N I N G S U R V E Y I N G 14711 NE 29th Place, #101 Bellevue, Washington 98007 425.885.7877 Fax 425.885.7963 KIDDIE RESEARCH DAYCARE CENTER 18227 EXISTING CONDITIONS Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-7 4.1.2 Developed Conditions See Developed Conditions exhibit on the following pages. The developed basin boundary area is equal to the existing basin boundary area, 0.39 acre. For simplicity to demonstrate exemption from flow control, the developed condition was conservatively assumed to be 100% impervious. The following information was used for generating flow frequencies. See MGS Flood printout below. DEVELOPED CONDITIONS Total Area = 0.39 acre GROUND COVER AREA(acres) Till-Grass 0.00 Impervious 0.39 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Developed Site ---------- -------Area (Acres) -------- Impervious 0.390 ---------------------------------------------- Subbasin Total 0.390 Predevelopment Runoff Tr (Years) Discharge (cfs) ---------------------------------------------- 2-Year 0.145 5-Year 0.189 10-Year 0.212 25-Year 0.267 50-Year 0.340 100-Year 0.393 200-Year 0.408 NE SUNSET BLVDNE 12TH STREET DESIGN E N G I N E E R I N G P L A N N I N G S U R V E Y I N G 14711 NE 29th Place, #101 Bellevue, Washington 98007 425.885.7877 Fax 425.885.7963 KIDDIE RESEARCH DAYCARE CENTER 18227 DEVELOPED CONDITIONS Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-9 ON-SITE BMPs Per Section 1.2.9.1 in the RSWDM, projects subject to Core Requirement #9 must apply flow control BMPs to either supplement the flow mitigation provided by required flow control facilities or provide flow mitigation where flow control facilities are not required. Flow control BMPs must be implemented per the requirements and approach detailed in Sections 1.2.9.2 and 1.2.9.3 for individual lots and subdivisions or road improvement projects, respectively. The Section applicable to this project is Section 1.2.9.2. Per Section 1.2.9.2, projects on individual sites/lots, flow control BMPs must be selected and applied according to the individual lot BMP requirements. The category of requirements applicable to the subject project is the Small Lot BMP Requirements (for sites/lots <22,000 square feet). 1. The feasibility and applicability of full dispersion as detailed in Appendix C, Section C.2.1 must be evaluated for all target impervious surfaces. If feasible and applicable, full dispersion must be implemented as part of the proposed project. Typically, small lot full dispersion will be applicable only in subdivisions where enough forest was preserved by tract, easement, or covenant to meet the minimum requirements for full dispersion in Appendix C, Section C.2.1.1 Full dispersion is not feasible due to non-existent native forested area. 2. Where full dispersion of target impervious roof areas is not feasible or applicable, or will cause flooding or erosion impacts, the feasibility and applicability of full infiltration as detailed in Appendix C, Section C.2.2 must be evaluated (note, this will require a soils report for the site/lot). If feasible and applicable, full infiltration of roof runoff must be implemented as part of the proposed project. Full infiltration is not feasible due to existing onsite non-infiltrating till soils. 3. All target impervious surfaces not mitigated by Requirements 1 and 2 above, must be mitigated to the maximum extent feasible using one or more BMPs from the following list. Use of a given BMP is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Feasible BMPs are required to be implemented. The BMPs listed below may be located anywhere on the site/lot subject to the limitations and design specifications for each BMP. These BMPs must be implemented as part of the proposed project. • Full Infiltration per Appendix C, Section C.2.2, or per Section 5.2, whichever is applicable Full infiltration is not feasible due to existing onsite non-infiltrating till soils • Limited Infiltration per Appendix C, Section C.2.3, Limited infiltration will be installed to mitigate for the roof area. The dry well will contain 360 cubic feet of gravel per 1,000 square feet of impervious surface served since the soils are sandy loam (RSWDM Section C.2.3.4). See copyclip of email below from the project’s geotechnical engineer. indicating the soils are “sandy loam”. The dry well will be a maximum depth of 5 feet with a surface area as sized below. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-10 Dry Well Sizing Roof Area = 7,738 square feet Volume of Gravel Required = 7,738 SF/1,000 SF * 360 CF = 2,786 cubic feet Surface Area Required = 2,786 CF/5 FT = 557 square feet Surface Area Provided = 10 FT * 56 FT = 560 square feet ˃ 557 square feet • Rain Gardens per Appendix C, Section C.2.12, sized as follows: o Rain gardens have a maximum contributing area of 5,000 square feet. o Rain gardens must have a minimum horizontal projected surface area below the overflow that is at least 5% of the area draining to it. The remaining impervious surfaces on the site discharge to the catch basin located within the covered parking area. Due to the parking being located under cover, all drainage is required to be directed to the sanitary sewer system. Therefore, no additional impervious area requires treatment via BMPs. • Bioretention per Appendix C, Section C.2.6, sized as follows: o SeaTac regional scale factor equals 1.0: In till soils, provide bioretention volume based on 0.6 inches of equivalent storage depth; in outwash soils provide bioretention volume based on 0.1 inches of equivalent storage depth, o SeaTac regional scale factor greater than 1.0: In till soils, provide bioretention volume based on 0.8 inches of equivalent storage depth; in outwash soils, provide bioretention volume based on 0.4 inches of equivalent storage depth, See response to Rain Gardens above. • Permeable Pavement per Appendix C, Section C.2.7 See response to Rain Gardens above. 4. All target impervious surfaces not mitigated by Requirements 1, 2 and 3 above, must be mitigated to the maximum extent feasible using the Basic Dispersion BMP described below. Use of Basic Dispersion is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Feasible BMPs are required to be implemented. Basic Dispersion BMPs may be located anywhere on Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-11 the site/lot subject to the limitations and design specifications cited in Appendix C. The BMP must be implemented as part of the proposed project. • Basic Dispersion per Appendix C, Section C.2.4, See response to Rain Gardens above. 5. BMPs must be implemented, at minimum, for an impervious area equal to at least 10% of the site/lot for site/lot sizes up to 11,000 square feet and at least 20% of the site/lot for site/lot sizes between 11,000 and 22,000 square feet. For projects located in Zone 1 of the Aquifer Protection Area, these impervious area amounts must be doubled. Doubling of the minimum impervious area required for BMP implementation in Zone 1 of the Aquifer Protection Area is not required for projects located within 200 feet of a steep slope hazard area, landslide hazard, or erosion hazard area. If these minimum areas are not mitigated using feasible BMPs from Requirements 1, 2, 3, and 4 above, one or more BMPs from the following list are required to be implemented to achieve compliance. These BMPs must be implemented as part of the proposed project. • Reduced Impervious Surface Credit per Appendix C, Section C.2.9, • Native Growth Retention Credit per Appendix C, Section C.2.10. • Tree Retention Credit per Appendix C, Section C.2.14 See response to Rain Gardens above. 6. The soil moisture holding capacity of new pervious surfaces (target pervious surfaces) must be protected in accordance with the soil amendment BMP as detailed in Appendix C, Section C.2.13. Soil amendment will be incorporated for disturbed areas not covered with hard surfaces. 7. Any proposed connection of roof downspouts to the local drainage system must be via a perforated pipe connection as detailed in Appendix C, Section C.2.11. As the drainage from the roof is passing through a BMP, this requirement is no longer applicable. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 4-12 4.2 Water Quality Treatment Analysis and Design The subject project is exempt from water quality treatment per the “Surface Area Exemption”; a) Less than 5,000 square feet of new plus replaced PGIS that is not fully dispersed will be created, New PGIS is approximately 1,512 square feet which is well below the 5,000 square foot threshold. b) Less than ¾ acre of new PGPS that is not fully dispersed will be added. The area of development is 0.39 acre which is well below the ¾ acre threshold. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 5-1 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN Conveyance system analysis and design will be addressed during final design. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 6-1 6. SPECIAL REPORTS AND STUDIES The following reports and assessments are provided for reference and informational purposes only. Core Design takes no responsibility or liability for these reports, assessments or designs as they were not completed under the direct supervision of Core Design. • Geotechnical Engineering Design Report by Mud Bay Geotechnical Services, LLC, dated 3/18/2019 GEOTECHNICAL ENGINEERING DESIGN REPORT 3123 Sunset Blvd NE Renton, WA 98056 Prepared for: Carson AuYeung Livia Chen Job No: 1054-KIN Chris J. Heathman, P.E. Principle Geotechnical Engineer Mud Bay Geotechnical Services, LLC J o b N o : 1 0 54-K I N Table of Contents 1. Introduction ....................................................................................................................... 1 1.1. General ........................................................................................................................ 1 1.2. Location and Description.............................................................................................. 1 2. Site Conditions .................................................................................................................. 1 2.1. Site Soils and Geology ................................................................................................. 1 2.2. Subsurface and Groundwater Conditions ..................................................................... 1 2.2.1. On-Site Soils ......................................................................................................... 1 2.2.2. Surface Water and Groundwater........................................................................... 2 3. Geologic Hazards .............................................................................................................. 2 3.1. Liquefaction Potential ................................................................................................... 2 3.2. Fault Rupture Hazard ................................................................................................... 2 4. Geotechnical Recommendations ..................................................................................... 3 4.1. Seismic Design ............................................................................................................ 3 4.2. Shallow Foundation Design and Construction .............................................................. 3 4.2.1. Shallow Foundation Support ................................................................................. 3 4.2.2 Lateral Earth Pressures ............................................................................................ 4 4.2.3. Slab-On-Grade Support ............................................................................................ 4 4.2.4. Foundation Drainage Considerations ........................................................................ 5 4.3. Utilities ......................................................................................................................... 5 4.4. Earthwork Considerations ............................................................................................ 5 4.4.1. Structural Fill ......................................................................................................... 5 4.4.2. Site Grading .......................................................................................................... 6 4.5. Temporary Slopes and Structural Shoring ................................................................... 6 5. Recommended Additional Services ................................................................................ 6 6. Intended Use and Limitations .......................................................................................... 6 7. References ........................................................................................................................ 7 LIST OF APPENDICES Appendix A – Field Exploration Program LIST OF FIGURES Figure 1 – Site Map Figure 2 – Site Plan Figure 3 – USDA Soil Map Figure 4 – Geologic Map Figure 5 – Site Exploration Map J o b N o : 1 0 5 4 -K I N LIST OF TABLES Table 1: Seismic Design Parameters ......................................................................................... 3 Table 2: Lateral Earth Pressure Parameters ............................................................... ………….4 J o b N o : 1 0 54-K I N P a g e | 1 1. Introduction 1.1. General This report presents the results of our geotechnical investigation and contains geotechnical recommendations for the project taking place at 3123 Sunset Blvd NE, Renton WA 98056. The analyses, conclusions, and recommendations in this report are based on one boring (designated as BH-1-19) completed specifically for this project, published geologic information for the site and vicinity and our experience with similar geologic materials. The conditions observed in the bore hole are assumed to be representative of the subsurface conditions throughout the project area. If during construction, subsurface conditions differ from those described in the explorations, we should be advised immediately so we may reevaluate the recommendations. 1.2. Location and Description The parcel is located at 3123 Sunset Blvd NE in Renton, WA. The site location and vicinity for the property are presented in Figure 1. The site has a history of previous development, which included a commercial building structure and pavement surface surrounding the building. The building was recently demolished, and the entire building and pavement was removed and cleared down to bare earth. The perimeter of the site facing Sunset Blvd NE and NE 12th St are landscaped with small bushes and shrubs interrupted by driveway access points. The scope of the project is to develop the site with an 8,000 to 10,000 SF, 2 to 3-story structure with ground floor to be used for commercial use as a daycare facility. It’s anticipated the structure will be supported on shallow strip footing foundations. The lowermost story may be a below ground basement level for additional parking. The existing property is graded at a relatively flat slope angle. An on-site treatment may be necessary, if infiltration testing and recommendations are required then it will be addressed in a separate report and is not within the scope of this report. 2. Site Conditions 2.1. Site Soils and Geology As part of this project, we reviewed available geologic data from the USDA Soil Conservation Survey and the Washington State Department of Natural Resources and prepared site-specific geology and soils maps, which are attached as Figures 3 and 4, respectively. The USDA Soil Conservation Survey map indicates the surface soils at the site consist of Arents, Alderwood Material, 6 to 15 percent slope. It should be noted the percent slope in these descriptions is an approximation. The project vicinity geologic map indicates the project site is underlain by Pleistocene Continental Glacial Till. The conditions in the explorations are generally consistent with the mapped soils and geology at the site. 2.2. Subsurface and Groundwater Conditions 2.2.1. On-Site Soils A single hand auger boring, designated BH-1-19, was performed to explore the subsurface conditions at the site location. The approximate location of the boring is shown on Figure 5. Based on the conditions observed in the boring, the soils at the site generally consist of moist, brownish J o b N o : 1 0 5 4 -K I N gray, gravelly sand. The upper 18 inches of soil is relatively loose due to the recent disturbance from demolition activities. The material below 18 inches deep is very dense based on the difficulty of advancing the hole. More detailed information regarding site soil conditions and a description of our field exploration and procedures is included in Appendix A. 2.2.2. Surface Water and Groundwater Groundwater was not encountered in boring BH-1-19. It’s not anticipated significant groundwater is present within the limits of the excavation to be performed as part of the construction of the project. However, based on the heterogeneous nature of the native glacial till, it is possible small pockets of perched groundwater will be encountered. Localized seepage is common within lenses of coarser grained sand and gravel contained in Pleistocene continental glacial till deposits mapped at the site. Localized seepage typically occurs in areas where coarser soils such as sands and gravels are trapped within finer grained silts and clays. The groundwater seepage within these trapped zones generally will not result in surface water seepage until exposed either through excavation cuts during construction or through natural erosion processes. There are no notable natural surface water bodies within the site vicinity. The site is in an urban environment with a significant amount of impervious surface. Surface water runoff from storm events directly falling onto the ground in this type of environment is generally collected and directed to detention or infiltration facilities such as swales and ponds, or to catch basins and conveyed through underground stormwater sewer facilities to an appropriate discharge location. A small amount of surface water will infiltrate into the ground within landscaped areas and green space. 3. Geologic Hazards 3.1. Liquefaction Potential Soil liquefaction is a phenomenon whereby saturated soil deposits temporarily lose strength and behave as a viscous fluid in response to cyclic loading. Soil types considered at the highest risk of liquefaction during a seismic event are loose sandy soils. Gravel material can be susceptible to liquefaction if it contains a significant fraction of sand-sized particles and is capped by less permeable material. Groundwater was not encountered in boring BH-1-19 to a depth of 7 feet. Furthermore, the site soils are not considered susceptible to liquefaction based on their high relative density and limited potential for groundwater at shallow depths, and therefore liquefaction is not a design consideration for this project. 3.2. Fault Rupture Hazard The potential impacts of fault rupture include abrupt, large, differential ground movement and associated damage to structures that might straddle the fault. The nearest active crustal fault is the Seattle Fault system. The closest mapped fault splay associated with the Seattle Fault system is located approximately 1.5 to 2.0 miles away from the project site. In our opinion, the risk of fault rupture at the site is low. J o b N o : 1 0 5 4 -K I N 4. Geotechnical Recommendations 4.1. Seismic Design Seismic design should be performed based on the design criteria and hazard maps in the 2015 International Building Code (IBC, 2015) for peak ground acceleration (PGA) at the site location based on the United States Geological Survey hazard maps for the 2,475 year recurrence interval at the site location (Peterson et. al, 2014). Adjustment factors should be applied to account for amplification as ground motions transmit from the bedrock surface up through the soil column to the ground surface. For design purposes, we recommend assuming Site Class D soils. Seismic design parameters for the site location are provided in Table 1. Table 1: Seismic Design Parameter s Site Class based on soil conditions Site Class = D Peak Horizontal ground acceleration coefficient on Class B rock PGA = 0.61 Site coefficient for the peak ground acceleration coefficient FPGA = 1.1 Effective peak ground acceleration coefficient (g) As=FPGA(PGA)= 0.67 4.2. Shallow Foundation Design and Construction 4.2.1. Shallow Foundation Support The site development of the parcel includes an 8,000 to 10,000 SF, 2 to 3-story structure with ground floor to be used for commercial use as a daycare facility. We anticipate that the structure will be supported on shallow strip footing foundations. In addition, the lowermost story may be a below ground basement level for parking. Shallow strip footings will be used to support the structure loads. We anticipate the footings will be supported on native glacial till soils. Prior to construction of the footings, the subgrade should be cleared and grubbed and the exposed native subgrade soils should be compacted in place. The subgrade should be inspected for any pockets of loose material. Loose material should be removed and replaced with a minimum of 6-inches of Crushed Surfacing Base Course (CSBC) meeting the requirements of Section 9-03.9(3) of the WSDOT Standard Specifications (WSDOT, 2018) or an equivalent material. The CSBC should be placed in layers no greater than 6-inches and compacted to at least 95 percent of the maximum dry density. Footings bearing on a subgrade prepared as described above can be designed using a maximum allowable bearing pressure of 3,500 psf. The maximum allowable bearing pressure may be increased by up to one-third for short-term transient loading conditions such as wind and seismic loading. We anticipate the total settlement will not exceed one inch, and differential settlement along a 50-foot length will not exceed half of the total settlement. The settlement is expected to be elastic and will occur as the footings are loaded. We recommend footing subgrade preparation be evaluated by Mud Bay Geotechnical Services, LLC prior to placement of concrete. Foundation subgrade preparation should not be performed during periods of wet weather. We recommend staging the foundation subgrade excavation, compaction of native subgrade soils, and placement of CSBC to limit the time the foundation subgrade is exposed to weather. J o b N o : 1 0 5 4 -K I N 4.2.2 Lateral Earth Pressures Retaining walls or stem walls should be designed to resist lateral earth pressures of the backfill placed behind the walls. For lateral load analysis, we recommend the geotechnical parameters in Table 2 be used for lateral design and analysis. Backfill behind the walls should be placed in horizontal layers no more than 6 inches thick with each layer compacted to 95 percent of the maximum density. The backfill material should be comprised of Gravel Backfill for Walls material meeting the requirements of Section 9-03.12(2) of the WSDOT Standard Specifications (WSDOT, 2018), or an equivalent free-draining material. Table 2: Lateral Earth Pressure Parameters Parameter Design Value Backfill Unit Weight (γ) 135 pcf Wall Backfill Soil Friction Angle (φf) 37° Coefficient of Sliding (tan φf) 0.55 Active Earth Pressure (Ka) 0.23 (EFP 31.1 psf) At Rest Earth Pressure (K0) 0.40 (EFP 54.0 psf) Passive Earth Pressure (Kp) 8.78 (EFP 1,185 psf) The passive earth pressure coefficient and coefficient of sliding presented in Table 2 are ultimate values and should be reduced by a factor of safety equal to 1.5 for final design. The lateral earth pressure coefficients provided in Table 2 are based on the use of Gravel Backfill for Walls. Active earth pressures can be assumed for design, provided that the walls can yield laterally at least 0.001H (where H is the exposed wall height in feet). If the wall is not capable of yielding that amount, then at-rest earth pressures should be used. Seismic loading represented as a rectangular shaped dynamic uniform lateral surcharge equal to 8H psf should be applied, with the resultant acting at a height of 0.5H, where H is the height of the wall. This value, which was calculated using the Mononobe-Okabe method, is appropriate for yielding walls designed in accordance with the 2015 IBC (IBC, 2015). 4.2.3. Slab-On-Grade Support All interior slabs-on-grade should be underlain by a capillary break at least 6 inches thick consisting of free-draining, clean, course sand and fine gravel with a maximum particle size of ¾- inch, no more than 50 percent passing the U.S. No. 4 sieve, and less than 5 percent passing the U.S. No. 200 sieve. Prior to placement of the capillary break layer, topsoil, mud, debris, and rootmass should be cleared and grubbed and the native subgrade soils should be compacted in-place to a dense and relatively unyielding condition. The six-inch capillary break layer should be compacted to at least 95 percent of the maximum dry density of the material. We recommend considering placement of a suitable vapor barrier to further retard moisture at the slab-on-grade. Similar to footing construction, it will be helpful to stage the excavation and subgrade preparation of slab-on-grade areas to limit the exposure to wet weather placement of the capillary break layer. J o b N o : 1 0 5 4 -K I N Once in place and compacted, the low-fines-content capillary break layer will reduce the likelihood that the subgrade is disturbed. We recommend using a vertical modulus (Kv1) of 85 pounds per cubic inch (pci) for slab-on- grade bearing on a subgrade prepared as described above. Note that Kv1 is appropriate for a 1-foot by 1-foot surface and the initial subgrade modulus used for design (Ks) will need to be adjusted based on the width of the footing or slab considered using the following equation: Ks = Kv1(B+1)2/(4B2) where B = foundation or slab width in feet. 4.2.4. Foundation Drainage Considerations It’s recommended including a perimeter footing drain system, consisting of a 4-inch diameter, perforated or slotted, rigid plastic pipe placed at the base of the wall footings. The drain should be embedded in a clean, free-draining sand and gravel meeting the requirements of Section 9- 03.12(4) of the WSDOT Standard Specifications for Gravel Backfill for Drains. The drains should be sloped slightly to drain to an appropriate discharge area. Appropriate water and weather proofing measures should be used in order to reduce the potential for leaks through the basement walls. 4.3. Utilities We anticipate that buried utilities will need to be constructed as part of the project. The utility subgrade (base of trench excavation) should be relatively firm prior to placing bedding materials. Subgrade observed to be soft, pumping, or containing abundant organics or refuse should be sub-excavated to firm subgrade soil or a maximum depth of 2 feet. Sub-excavated areas should be backfilled with structural fill. Material placed directly below, around, and above utility pipes should consist of Gravel Backfill for Pipe Zone Bedding as described in Section 9-03.12(3) of the WSDOT Standard Specifications (WSDOT, 2018). The pipe bedding materials should be placed and compacted to a relatively firm condition in accordance with the manufacturer’s specifications. Bedding and cover should be a minimum of 6-inches thick. 4.4. Earthwork Considerations 4.4.1. Structural Fill Soils placed as fill beyond the limits of foundation subgrade, wall backfill, and pipe zone areas described previously should be considered structural fill. Structural fill should consist of material meeting the requirements of Common Borrow as described in Section 9-03.14(3) of the WSDOT Standard Specifications (WSDOT, 2018). Based on the conditions observed in boring BH-1-19, the onsite material to be removed for construction meets the requirements for Common Borrow. Structural fill should be placed and compacted in lifts no greater than 8 inches when using relatively large compaction equipment, such as a vibrating compaction equipment attached to an excavator or a drum roller. If small, hand-operated compaction equipment is used to compact the J o b N o : 1 0 5 4 -K I N structural fill, fill lifts should not exceed 6 inches. Based on the small size of the project and difficult access, most likely relatively large compaction equipment will be used. Structural fill should be placed and compacted to between 90 and 92 percent of the maximum dry density. All other fill material should be placed and compacted as described previously. Fill placed in softscape, landscape, or common areas that can accommodate some settlement should be compacted to a relatively firm and unyielding condition. 4.4.2. Site Grading We recommend grading all permanent cuts and fills to a maximum slope angle of 2H:1V. Until a layer of vegetation is established, the upper 1 to 2 feet below the surface of the slope may be only marginally stable. To reduce the potential for short term erosion, coir, jute, or turf reinforcement mat should be placed on the surface of the slope until vegetation is established. 4.5. Temporary Slopes and Structural Shoring Stability for all other temporary excavation slopes, structural shoring, and temporary works necessary to complete the project not shown in the plans for the project remain the responsibility of the Contractor. The Contractor will determine the appropriate measures to ensure all excavation is in compliance with local, state and federal safety codes. Washington Administrative Code 296-155 (WAC, 2009) contains specific requirements for trenches and temporary slopes. For planning and cost estimating purposes, we recommend assuming 1H:1V temporary slopes are feasible. 5. Recommended Additional Services Before construction begins, we recommend a copy of the draft plans and specifications prepared for the project be made available for review so we can ensure the geotechnical recommendations in this report are included in the Contract. Mud Bay Geotechnical Services, LLC is also available to provide geotechnical engineering and construction monitoring services throughout the remainder of the design and construction of t he project. The integrity of the geotechnical elements of a project depend on proper site preparation and construction procedures. In addition, engineering decisions may need to be made in the field if conditions are encountered differ from those described in this report. During the construction phase of the project, we recommend Mud Bay Geotechnical Services, LLC be retained to review construction submittals, observe and evaluate subgrade for all slabs- on-grade and footings, and provide recommendations for any other geotechnical considerations that may arise during construction. 6. Intended Use and Limitations This report has been prepared to assist the client and their consultants in the engineering design and construction of the subject project. It should not be used, in part or in whole for other purposes without contacting Mud Bay Geotechnical Services, LLC for a review of the applicability of such reuse. This report should be made available to prospective contractors for their information only and not as a warranty of ground conditions. J o b N o : 1 0 5 4 -K I N The conclusions and recommendations contained in this report are based on Mud Bay Geotechnical Services, LLC understanding of the project at the time the report was written and on-site conditions existing at time of the field exploration. If significant changes to the nature, configuration, or scope of the project occur during the design process, we should be consulted to determine the impact of such changes on the recommendations and conclusions presented in this report. Site exploration and testing describes subsurface conditions only at the sites of subsurface exploration and at the intervals where samples are collected. These data are interpreted by Mud Bay Geotechnical Services, LLC rendering an opinion regarding the general subsurface conditions. Actual subsurface conditions can be discovered only during earthwork and construction operations. The distribution, continuity, thickness, and characteristics of identified (and unidentified) subsurface materials may vary considerably from that indicated by the subsurface data. While nothing can be done to prevent such variability, Mud Bay Geotechnical Services, LLC is prepared to work with the project team to reduce the impacts of variability on project design, construction, and performance. We appreciate the opportunity to serve your geotechnical needs on this project, and look forward to working with you in the future. Please contact us at your earliest convenience if you have any questions or would like to discuss the contents of this report. 7. References International Building Code (IBC), 2015, International Building Code, prepared by International Code Council. Petersen, M.D., et al., 2014, Documentation for the 2014 update of the United States national seismic hazard maps: U.S. Geological Survey Open-File Report 2014–1091, 243 p., https://dx.doi.org/10.3133/ofr20141091. Washington Administrative Code (WAC), 2009, April 1, 2009. Washington Department of Natural Resources Division of Geology and Earth Resources (DNR), 2016, https://geologyportal.dnr.wa.gov, accessed 8/26/2018 06:05 PM. Washington State Department of Transportation (WSDOT), 2015, Geotechnical Design Manual, Washington State Department of Transportation, Olympia WA. (www.wsdot.wa.gov/ Publications/Manuals/M46-03.htm) Washington State Department of Transportation (WSDOT), 2018, Standard Specifications for Road, Bridge, and Municipal Construction, Washington State Department of Transportation, Olympia WA. (www.wsdot.wa.gov/Publications/Manuals/M41-10.htm) Site Location Figure 1: Site Map 3123 NE Sunset Blvd, Renton, WA 98056 Site Development Geotechnical Report JOB #: 1054-KIN Date: March, 2019 Figure 2: Site Plan 3123 NE Sunset Blvd, Renton, WA 98056 Site Development Geotechnical Report JOB #: 1054-KIN Date: March, 2019 LEGEND Site Location Figure 2: Geology Map 216 9th Ave SE Olympia, WA 98501 Seismic Retrofit Geotechnical Report JOB #: 1040-THU Date: February, 2018 Figure 3: Geologic Map 3123 NE Sunset Blvd, Renton, WA 98056 Site Development Geotechnical Report JOB #: 1054-KIN Date: March, 2019 Sources: City of Olympia, Bureau of Land Management, Esri, HERE, Garmin, INCREMENT P, NGA, USGS | Washington Division of Geology and Earth Resources Sources: City of Renton, County of King, Bureau of Land Management, Esri, HERE, Garmin, INCREMENT P, NGA, USGS | Washington Division of Geology and Earth Resources N Legend Site location AmC Arents, Alderwood material, 6 to 15 percent slopes Ur Urban land Figure 4: USDA Soil Map 3123 NE Sunset Blvd, Renton, WA 98056 Site Development Geotechnical Report JOB #: 1054-KIN Date: March, 2019 Sample Collection Location BH-1-19 N JOB #: 1054-KIN Date: March, 2019 Figure 5: Site Exploration Map 3123 NE Sunset Blvd, Renton, WA 98056 Site Development Geotechnical Report APPENDIX A – FIELD EXPLORATION PROGRAM FIELD EXPLORATION PROGRAM To characterize the surface and subsurface conditions for the project, Mud Bay Geotechnical Services, LLC performed a single boring, designated BH-1-19. The boring was completed from the existing ground surface at the approximate location shown on Figure 5. The boring was completed using a Humboldt Manufacturing model H-4206.6A hand auger with a 3 ¼ inch diameter bucket tube sampler. A prybar was used at selected locations to break up some of the gravel particles in order to facilitate advancing the hole. The soil samples were classified visually in the field in general accordance with ASTM D2488, the Standard Practice for Description and Identification of Soils (Visual-Manual Procedure). Once transported back to the office, the samples were re-examined and the field classifications were modified accordingly. A summary log of the boring is included in Appendix A. Note the soil descriptions and interfaces shown on the log are interpretive, and actual changes may be gradual. Upon completion, the hole was backfilled to the original ground surface using excavated material from the spoil pile. Completed:Hammer Type: Backfilled:Hammer Weight:Hammer Drop: Groundwater Depth:Total Depth of Boring: Lithology Note: the upper 18" was made up of construction overburden Moist, brownish gray, gravelly sand, with med grain gravels, (SW) Moist, brownish gray, gravelly sand, with med grain gravels, (SW) Standard Penetration Slit Spoon Sampler (SPT) Blows/3/4"Density 0-4 Very Loose 5-10 Loose 11-24 Medium Dense 25-50 Dense >50 Vey Dense REF Refusal Moisture Content (%)Additional TestSoil Group Name: modifier, color, moisture, density/consistency, grain size, other descriptors Rock Description: modifierm color, hardness/degree of concentration, bedding and joint characteristics, solutions, void conditions.Graphic LogDateSite Development 3/1/2019 Address:Started: Logan Krehbiel 3123 Sunset Blvd, Renton WA 98056 Project Number: 1054-KIN Gravel, Sand, Non-Plastic Silt Elastic Silts and Clays Bailly & Bailly LLC BH-1-19 3/1/2019 3/1/2019 n/a Hand Auger n/a Dry Density (pcf)Client:Boring No. 1 of 2: Drilling Contractor:Drill Rig Type: 3.25 inches Steel n/a Soil Density Modifiers Bit Type:Diameter: Fluid: none Elevation: Existing Surface 84" n/a n/a Bore Log Symbols Logged By: Samantha Denham Drill Crew: Project:Depth (feet)Sample TypeSample NumberBlow Counts (blows/3/4")California Sampler Shelby Tube CPP Sampler StabIlized Ground water Groundwater At time of Drilling Bulk/ Bag Sample Blows/3/4" 0-1 2-4 5-8 9-15 16-30 31-61 Very Stiff 31-60 Consistency Very Soft Soft Medium Stiff Stiff Hard Very Hard 3 6 S-1 S-2 n/a n/a Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 7-1 7. OTHER PERMITS No other permits relevant to this Preliminary TIR are known to be required at this time. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 8-1 8. ESC ANALYSIS AND DESIGN The ESC analysis and design will be addressed during final design. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 9-1 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT The bond quantities, facility summary, and declaration of covenant will be addressed during final design. Core Design, Inc. KIDDIE RESEARCH DAYCARE CENTER Page 10-1 10. OPERATIONS AND MAINTENANCE The operations and maintenance manual will be addressed during final design.