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REVIEWED ENG PLN2021-0037+Geotech Report+2.4.2022_10.52.48_AM+2662072EarthSolutionsNWLLC EarthSolutionsNWLLC 15365 N.E.90th Street,Suite 100 Redmond,WA 98052 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com Geotechnical Engineering Construction Observation/Testing Environmental Services GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL DEVELOPMENT BRACKET’S RESERVE 9125 –240 STREET SOUTHWEST EDMONDS,WASHINGTON ES-7610.01 TH PREPARED FOR PACIFIC RIDGE – DRH, LLC June 18, 2021 _____________________ Henry T. Wright, P.E. Senior Project Manager _____________________ Kyle R. Campbell, P.E. Principal Engineer GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL DEVELOPMENT BRACKET’S RESERVE 9125 – 240TH STREET SOUTHWEST EDMONDS, WASHINGTON ES-7610.01 Earth Solutions NW, LLC 15365 Northeast 90th Street, Suite 100 Redmond, Washington 98052 Phone: 425-449-4704 | Fax: 425-449-4711 www.earthsolutionsnw.com 06/18/2021 Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical-Engineering Services Provided for this ReportGeotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities. The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions. Geotechnical-Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific TimesGeotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Likewise, geotechnical-engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical- engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project. Do not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project or purpose; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time – if any is required at all – could prevent major problems. Read this Report in Full Costly problems have occurred because those relying on a geotechnical- engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full. You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project-specific factors when developing the scope of study behind this report and developing the confirmation-dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect: • the site’s size or shape; • the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance criteria; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-Dependent The recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be Misinterpreted Other design professionals’ misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to: • confer with other design-team members; • help develop specifications; • review pertinent elements of other design professionals’ plans and specifications; and • be available whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction-phase observations. Give Constructors a Complete Report and GuidanceSome owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to find environmental risk-management guidance. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer’s services were not designed, conducted, or intended to prevent migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation. Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org June 18, 2021 ES-7610.01 Pacific Ridge – DRH, LLC 17921 Bothell-Everett Highway, Suite 100 Bothell, Washington 98012 Attention: Mr. John Mirante Dear Mr. Mirante: Earth Solutions NW, LLC (ESNW) is pleased to present this report titled “Geotechnical Engineering Study, Proposed Residential Development, Bracket’s Reserve, 9125 – 240th Street Southwest, Edmonds, Washington”. Based on the results of our study, the proposed residential development is feasible from a geotechnical standpoint. Based on the conditions observed during our fieldwork, the subject site is underlain by glacial till deposits. The site will be mass graded to create an access road and building pads. New structural fill should be placed on competent native soil. If earthwork activities occur during wet weather, additional drainage measures, cement treatment of native soil, and/or the use of select fill material will likely be necessary. After completing earthwork activities in accordance with recommendations in this report, the proposed structures can be supported on conventional spread and continuous foundations bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. If structural building pads are disturbed during wet weather, remediation measures such as cement treatment or overexcavation and replacement with rock may be necessary in some areas. This report provides analyses and recommendations for the proposed residential development. The opportunity to be of service to you is appreciated. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Henry T. Wright, P.E. Senior Project Manager 15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 •(425) 449-4704 • FAX (425) 449-4711 Earth Solutions NW LLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services Earth Solutions NW, LLC Table of Contents ES-7610.01 PAGE INTRODUCTION ................................................................................. 1 General..................................................................................... 1 Project Description ................................................................. 2 SITE CONDITIONS ............................................................................. 2 Surface ..................................................................................... 2 Subsurface .............................................................................. 2 Topsoil and Fill ............................................................. 3 Native Soil ..................................................................... 3 Geologic Setting ........................................................... 3 Groundwater ................................................................. 3 Geologically Hazardous Areas Assessment ........................ 3 Slope Reconnaissance ................................................ 4 Erosion Hazard Areas .................................................. 4 Landslide Hazard Areas ............................................... 5 Mapping of Geologically Hazardous Areas ................ 6 Special Study and Report Requirements ................... 6 Development Standards (General Requirements) ..... 8 Development Standards (Specific Hazards) .............. 9 Slope Stability Analysis ............................................... 10 DISCUSSION AND RECOMMENDATIONS ....................................... 10 General..................................................................................... 10 Site Preparation and Earthwork ............................................. 11 Temporary Erosion Control ......................................... 11 Stripping ....................................................................... 12 In-situ and Imported Soils ........................................... 12 Wet Season Grading .................................................... 12 Structural Fill ................................................................ 13 Modular Block Walls and Rockeries ........................... 13 Excavations and Slopes .............................................. 13 Foundations ............................................................................ 14 Seismic Design ....................................................................... 14 Slab-On-Grade Floors ............................................................. 15 Retaining Walls ....................................................................... 16 Drainage................................................................................... 16 Infiltration Evaluation ................................................... 17 On-site Stormwater Management ............................... 17 Stormwater Vault Design ............................................. 19 Earth Solutions NW, LLC Table of Contents Cont’d ES-7610.01 PAGE Utility Support and Trench Backfill ....................................... 20 Preliminary Pavement Sections ............................................. 20 LIMITATIONS ...................................................................................... 21 Additional Services ................................................................. 21 GRAPHICS Plate 1 Vicinity Map Plate 2 Test Pit Location Plan Plate 3 Retaining Wall Drainage Detail Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Test Results Appendix C Slope Stability Analysis Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL DEVELOPMENT BRACKET’S RESERVE 9125 – 240TH STREET SOUTHWEST EDMONDS, WASHINGTON ES-7610.01 INTRODUCTION General This geotechnical engineering study (study) was prepared for the proposed residential development to be constructed at 9125 – 240th Street Southwest in Edmonds, Washington. To complete the scope of services we performed the following:  Laboratory testing of soil samples collected at the test pit locations;  Engineering analyses and recommendations for the proposed development, and;  Preparation of this report. The following documents and resources were reviewed as part of our report preparation:  Soil Summary and Preliminary Geotechnical Recommendations, prepared by ESNW, ES- 7610.01, dated November 3, 2020;  Preliminary Plat Plan and Slope Map, prepared by RAM Engineering, Inc., undated;  Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, Washington, compiled by James P. Minard, 1983;  Geotechnical Design Manual (Chapter 5.13.3), Washington State Department of Transportation, dated October 2013;  Engineering Geology in Washington, Volume 1, Geotechnical Properties of Geologic Materials, Koloski et al.;  Edmonds City Code and Community Development Code (ECDC);  City of Edmonds GIS;  Web Soil Survey (WSS) online resource, maintained by the Natural Resources Conservation Service under the United States Department of Agriculture, and;  2012 Stormwater Management Manual for Western Washington, as amended in December 2014 (The 2014 SWMMWW). Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 2 Earth Solutions NW, LLC Project Description Based on the referenced preliminary plat plan, the site will be developed with 11 residential lots, an access road, a stormwater detention vault, and associated improvements. Grading for the project will include cuts of up to about 20 feet and fills of up to about 12 feet to create the site road and building pad elevations. Modular block walls and/or rockeries will be constructed to accommodate the proposed site grading. We understand stormwater will be conveyed to detention vault located in the southwestern area of the site. Site improvements will also include underground utility installations. At the time this report was prepared, specific building load values were not available. However, we anticipate the proposed residential structures will consist of relatively lightly loaded wood framing supported on conventional foundations. Based on our experience with similar developments, we estimate wall loads on the order of one to two kips per linear foot and slab-on- grade loading of 150 pounds per square foot (psf). If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW has reviewed the referenced plans as part of this report preparation. SITE CONDITIONS Surface The subject site is located at 9125 – 240th Street Southwest in Edmonds, Washington, as illustrated on the Vicinity Map (Plate 1). The site consists of four tax parcels (Snohomish County parcel numbers 0046330130-0400, -0301, -0303, and 0046330120-0403) totaling about 2.51 acres. The site is currently developed with multiple single-family residences and associated improvements; the remainder of the site consists of forested and overgrown areas. The site topography consists of a knoll feature with overall topography descending toward the west; some areas are moderately to steeply sloped. As illustrated on the referenced slope map, there are some areas within the site that are sloped steeper than 40 percent. We estimate maximum slope gradients of about 60 percent, with typical slope gradients of about 30 to 40 percent within the sloped areas of the site. Slope heights are about 10 to 20 feet. Subsurface As part of the subsurface exploration, five test pits were excavated at accessible locations of the site for the purpose of assessing the soil and groundwater conditions using a mini-track excavator and operator retained by ESNW. The test pits were advanced to refusal on very dense, cemented soil at depths of approximately four to six feet below the existing ground surface (bgs). Please refer to the test pit logs provided in Appendix A for a more detailed description of the subsurface conditions. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 3 Earth Solutions NW, LLC Topsoil and Fill Topsoil was encountered generally within the upper four to eight inches of existing grades at the test pit locations; thicker topsoil extending to a depth of 16 inches was encountered at TP-1 which was identified as fill. The topsoil was characterized by dark brown color, the presence of fine organic material, and small root intrusions. Fill was encountered at TP-1 extending to a depth of approximately two and one-half feet bgs. The fill consisted of topsoil and silty sand with gravel soil. Existing fill should also be anticipated within vicinity of existing site improvements. Native Soil Underlying the topsoil and fill, native soils were encountered primarily as silty sand (Unified Soil Classification System: SM), consistent with the typical makeup of glacial till; moderately to strongly cemented poorly graded sand with silt soil (Unified Soil Classification System: SP-SM) was encountered at two of the test pit locations. The near-surface, loose to medium dense deposits may be characterized as “weathered”, and the underlying, dense to very dense deposits may be characterized as “unweathered”. The unweathered glacial till (hardpan) was observed to be moderately to strongly cemented at the test pit locations. Native soils were observed primarily in a moist condition. Overall soil relative density generally increased with depth. Geologic Setting Geologic mapping of the area indicates the site and surrounding area is underlain by glacial till deposits (Qvt). The referenced WSS resource identifies urban land-Alderwood complex (map unit: 3057) across the majority of the site. The urban land designation denotes the land has been modified. The Alderwood series soils are generally consistent with glacial till deposits. Soil conditions observed at the test pit are generally consistent with glacial till deposits and Alderwood series soils. Groundwater During our subsurface exploration, zones of shallow perched groundwater seepage were encountered in some test pit locations. Perched seepage may be encountered in site excavations depending on the time of the year excavations take place. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the wetter, winter, spring, and early summer months. Geologically Hazardous Areas Assessment As part of this geotechnical engineering study, Chapter 23.80 of the ECDC was reviewed. Per the ECDC requirements, the following topics related to development plans and site conditions are addressed. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 4 Earth Solutions NW, LLC Slope Reconnaissance During our fieldwork, we performed a visual slope reconnaissance of the steep slope areas. The main focus of our reconnaissance was to identify signs of instability or erosion hazards along the site slopes. The typical instability indicators include features such as head scarps, tension cracks, hummocky terrain, groundwater seeps along the surface and erosion features such as gulley’s and rills. During the slope reconnaissance, no signs of erosion or slope instability were observed. The slope areas are vegetated with mature trees, ferns, salal, and some blackberries. Erosion Hazard Areas – ECDC 23.80.020.A. With respect to erosion hazard areas, section 23.80.020.A. of the ECDC defines erosion hazards as “at least those areas identified by the U.S. Department of Agriculture’s Natural Resources Conservation Service as having a ‘moderate to severe’, ‘severe’, or ‘very severe’ rill and inter-rill erosion hazard. Erosion hazard areas are also those areas impacted by shoreland and/or stream bank erosion. Within the city of Edmonds, erosion hazard areas include: 1. Those areas of the city of Edmonds containing soils that may experience severe to very severe erosion hazard. This group of soils includes, but is not limited to, the following when they occur on slopes of 15 percent or greater: a. Alderwood soils (15 to 25 percent slopes); b. Alderwood/Everett series (25 to 70 percent slopes), and; c. Everett series (15 to 25 percent slopes). 2. Coastal and stream erosion areas which are subject to the impacts from lateral erosion related to moving water such as stream channel migration and shoreline retreat; 3. Any area with slopes of 15 percent or greater and impermeable soils interbedded with granular soils and springs or ground water seepage, and; 4. Areas with significant visible evidence of ground water seepage, and which also include existing landslide deposits regardless of slope.” The site soils are generally consistent with Alderwood series soils. Based on the ECDC definition, the areas sloped 15 percent or steeper classify as erosion hazard areas. In our opinion, construction of the proposed project will not negatively impact the erosion hazard of the site or adjacent properties provided the recommendations in this report and illustrated on the temporary erosion and sediment control plan, prepared by a civil engineer, are followed. Typical Best Management Practices (BMPs), such as silt fences, covering exposed soil, swales, check dams, and temporary surface water detention systems should be implemented during construction as warranted. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 5 Earth Solutions NW, LLC Landslide Hazard Areas – ECDC 23.80.020.B. With respect to landslide hazard areas, section 23.80.020.B. of the ECDC defines landslide hazard areas as “areas potentially subject to landslides based on a combination of geologic, topographic, and hydrologic factors. They include areas susceptible because of any combination of soil, slope (gradient), slope aspect, structure, hydrology, or other factors. Within the city of Edmonds, potential landslide hazard areas include: 1. Areas of ancient or historic failures in Edmonds which include all areas within the earth subsidence and landslide hazard area as identified in the 1979 report of Robert Lowe Associates and amended by the 1985 report of GeoEngineers, Inc., and further discussed in the 2007 report by Landau Associates; 2. Coastal areas mapped as class U (unstable), UOS (unstable old slides) and URS (unstable recent slides) in the Department of Ecology Washington coastal atlas; 3. Areas designated as quaternary slumps, earthflows, mudflows, or landslides on maps published by the United States Geological Survey or Washington State Department of Natural Resources; 4. Any slope of 40 percent or steeper that exceeds a vertical height of 10 feet over a 25-foot horizontal run. Except for rockeries that have been engineered and approved by the engineer as having been built according to the engineered design, all other modified slopes (including slopes where there are breaks in slopes) meeting overall average steepness and height criteria should be considered potential landslide hazard areas; 5. Any slope with all three of the following characteristics: a. Slopes steeper than 15 percent; b. Hillsides intersecting geologic contacts with relatively permeable sediment overlying a relatively impermeable sediment, and; c. Springs or ground water seepage; 6. Any area potentially unstable as a result of rapid stream incision or stream bank erosion; 7. Any area located on an alluvial fan, presently subject to, or potentially subject to, inundation by debris flow or deposition of stream-transported sediments, and; 8. Any slopes that have been modified by past development activity that still meet the slope criteria.” Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 6 Earth Solutions NW, LLC Based on the referenced slope map, there are some areas along the western side of the site which are 40 percent or steeper that exceed a vertical height of 10 feet. Based on the slope map, these areas are about 10 to 14 feet in height. Per criterion 4. in the above definition of landslide hazard areas, the identified steep slope areas along the western side of the site classify as potential landslide hazard areas. As discussed previously, no indications of instability were observed during our slope reconnaissance. Additionally, the site is underlain by high strength glacial till deposits. If the recommendations in this report are incorporated into the design and construction of the proposed project, the project will not decrease stability of the subject site or adjacent properties. Ultimately, it is our opinion that the site slopes present a low landslide hazard based on the high strength of the underlying glacial till soil. Mapping of Geologically Hazardous Areas – ECDC 23.80.030 Review of City of Edmonds GIS mapping indicates a few isolated landslide hazard areas and an erosion hazard area present within and adjacent to the site. Special Study and Report Requirements – ECDC 23.80.050 A. This geotechnical engineering study and geological hazards assessment was completed by a professional engineer licensed in the state of Washington with experience analyzing geologic hazards throughout the Puget Sound region. B. Area addressed in this critical areas report: 1. The project area includes the subject site as delineated on Plate 2 of this report and on the referenced preliminary plat plan. 2. Other than the slope features discussed in this report which partially extend beyond the subject property boundaries, no further geologically hazardous areas have been identified within 200 feet of the property or will be affected by construction on the property. C. This geological hazards assessment included a field investigation and an assessment of geologic hazards. This geotechnical report has been prepared, stamped, and signed by a qualified professional. 1. It is our opinion the level of analysis completed for this geological hazards assessment is appropriate for the scale and scope of the project and scale of the geological hazard areas present. 2. A discussion of all geologically hazardous areas on the site and any geologically hazardous areas off site potentially impacted by the proposed project is provided in this report. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 7 Earth Solutions NW, LLC 3. Based on the results of our study, the proposed project will not decrease slope stability or pose an unreasonable threat to persons or property either on or off site. These conclusions are based on the current conditions of the slope areas in question and the proposed project. 4. In our opinion, this report provides adequate information to determine compliance with the requirements of ECDC Chapter 23.80. 5. This geotechnical report generally follows the guidelines set forth in the Washington State Department of Licensing Guidelines for Preparing Engineering Geology Reports in Washington (2006). 6. It is our opinion a landslide hazard minimum building setback is not necessary, and erosion hazard mitigation recommendations are provided in this report with respect to erosion control measures. D. We are not aware of a previous study completed for the subject site. E. It is our opinion that specific hazard mitigation, beyond typical erosion control measures, is not required; the recommendations within this report should be incorporated into construction of the project. F. This geological hazards assessment and geotechnical report should be reviewed as part of the overall submittal package. 1. Please refer to preliminary plans prepared by RAM Engineering, Inc. for the site plan. a. The height of the slopes and slope gradients are discussed in this report. b. Springs, seeps, or other surface expressions of groundwater were not observed on site or within 200 feet of the project area. c. Existing surface water runoff features are limited to downspouts from the existing houses. 2. Hazards analysis: a. Vegetative cover consists of mature trees, ferns, salal, and some blackberries. b. Subsurface conditions are described in the Subsurface section of this report. c. Surface and groundwater conditions are discussed in previous sections of this report. Based on current conditions, it is evident that some degree of land modification has occurred within and adjacent to some of the potential landslide hazard areas. The modifications were likely a result of historic site development and adjacent right-of-way construction. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 8 Earth Solutions NW, LLC d. The slopes within and adjacent to the subject site generally exhibit good overall stability and the proposed project will have a minimal impact to the slopes; a quantitative slope stability analysis is provided in this report. e. The slopes within and adjacent to the subject site are not characterized as bluffs and we do not anticipate a retreat of the slopes to occur. The potential for a landslide event during seismic activity or a 100-year storm event would likely be confined to the upper few feet of weathered soil. f. If a landslide were to occur, we would anticipate it to be confined to the upper few feet of weathered soil. The run-out hazard of a shallow debris flow slide would result in saturated sediment piling up near the toe of the slope and would likely not extend much beyond the height of slope from the toe of the slope. g. A slope stability analysis is provided in this report. h. It is our opinion that building siting limitations are not necessary with respect to the proposed project layout illustrated on the preliminary plat plan. i. The proposed surface and subsurface drainage will result in controlling stormwater within a contained storm system and will not increase the site vulnerability to erosion. 2. This geotechnical engineering study was prepared by a licensed engineer. a. Geotechnical design parameters are provided within this report. b. Drainage and subdrainage recommendations are provided within this report. c. Earthwork recommendations are provided within this report. d. Recommendations for mitigation of adverse site conditions are provided within this report, as necessary. G. It is our opinion the site erosion hazard areas should be considered stable. H. Based on the results of our study, the site does not contain any seismic hazard areas. Development Standards (General Requirements) – ECDC 23.80.060 Based on the results of our geological hazards assessment, the proposed project will not increase the threat of the geological hazard to adjacent properties beyond predevelopment conditions, the proposed project will not adversely impact other critical areas, the proposed project is designed so that the hazard to the project is eliminated or mitigated to a level equal to or less than predevelopment conditions, and the project is certified as safe as designed under anticipated conditions. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 9 Earth Solutions NW, LLC Development Standards (Specific Hazards) – ECDC 23.80.070 A. 1. Provided the recommendations in this report are incorporated into the construction of the project, the proposed project will not be at increased risk of landslides for the design life of the structures. In this respect, it is our opinion that a minimum building setback is not necessary for the proposed project. This determination is based on the stable nature of the site soil conditions and the results of our analysis. The recommendations set forth in this report will not result in an increased risk of landslides on or adjacent to the subject property. 2. Based on the results of our study, it is our opinion that a buffer is not necessary for the currently proposed project. 3. The proposed project will include alterations of some potential landslide hazard areas and erosion hazard areas. a. In our opinion, the proposed alterations will not increase surface water discharge or sedimentation to adjacent properties beyond predevelopment conditions. b. Based on the results of our analysis, the proposed alterations will not decrease slope stability on adjacent properties. c. The proposed alterations will not adversely impact other critical areas. 4. a. As part of this geological hazards assessment, we completed slope stability analysis for the existing and proposed conditions. Results of the slope stability analysis indicate safety factors greater than 1.5 for static and 1.2 for seismic. b. It is our opinion that the structures and improvements have been located and engineered in a manner which sufficiently mitigates impacts to the sloped areas which will remain unaltered. c. We understand the site has been designed in a manner which conforms to the existing topography to the extent practicable. d. The structures and improvements have been located and engineered in a manner that retains the most critical portions of slope areas (western edge of the property) as well as natural landforms and vegetation. e. The proposed development will not result in greater risk or a need for increased buffers on neighboring properties. f. Retaining walls are proposed to accommodate grade changes rather than graded artificial slopes. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 10 Earth Solutions NW, LLC Slope Stability Analysis ESNW completed a quantitative slope stability analysis of the existing and proposed site conditions using Morgenstern-Price methodology with GeoStudio 2021 Slope/W software. Soil strength parameters and groundwater conditions included in the analysis are representative of the high strength, glacial till deposits observed at the site and are generally conservative with respect to the recommended design values provided in the referenced geotechnical properties and design documents. The slope stability analysis was completed through a representative critical cross-section extending through and beyond the proposed project area; the location of the cross-section is displayed on Plate 2 (Test Pit Location Plan). The static and seismic factors of safety (FS) for critical slip surfaces are provided below. Cross-Section Static FS Seismic FS Existing Condition 4.1 1.9 Proposed Condition 4.1 2.0 The results of our analyses, as well as additional modeling parameters, are provided in Appendix C of this report. In accordance with the ECDC and utilizing USGS Seismic Design Maps, a peak horizontal ground acceleration (PGA) value of 0.651g was used for the subject site. The pseudostatic coefficient used in the stability analyses was equivalent to one-half of the PGA, or 0.326g, which is conservative for the height of the slope modeled. The analysis yielded that the proposed conditions minimum FS values are not reduced from the existing condition values. Based on our visual observations, computer modeling, and subsurface data, it is our opinion site landslide susceptibility within the proposed building area can generally be characterized as low; furthermore, our analysis indicates the proposed project will not increase site susceptibility to landslide activity provided the recommendations in this report are incorporated into site construction. DISCUSSION AND RECOMMENDATIONS General Based on the results of our investigation, construction of the proposed residential development is feasible from a geotechnical standpoint. The primary geotechnical considerations associated with the proposed development include site preparation and earthwork, utility installation, foundation support, drainage, and the suitability of using on-site soils as structural fill. The site will be mass graded to create an access road and building pads. New structural fill should be placed on competent native soil. If earthwork activities occur during wet weather, additional drainage measures, cement treatment of native soil, and/or the use of select fill material will likely be necessary. After completing earthwork activities in accordance with recommendations in this report, the proposed structures can be supported on conventional spread and continuous foundations bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. If structural building pads are disturbed during wet weather, remediation measures such as cement treatment or overexcavation and replacement with rock may be necessary in some areas. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 11 Earth Solutions NW, LLC This study has been prepared for the exclusive use of Pacific Ridge – DRH, LLC and their representatives. No warranty, expressed or implied, is made. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Site Preparation and Earthwork Temporary erosion and surface water control measures must be implemented prior to and concurrent with site mass grading. Grading for the project will include cuts of up to about 20 feet and fills of up to about 12 feet to create the site road and building pad elevations. Modular block walls and/or rockeries will be constructed to accommodate the proposed site grading. Once temporary erosion control measures have been installed, the site can be stripped and grading operations can commence. If earthwork activities occur during wet weather, additional drainage measures, cement treatment of native soil, and the use of select fill material will likely be necessary. Temporary Erosion Control The following temporary erosion control measures should be considered:  Temporary construction entrances and drive lanes, consisting of at least six inches of quarry spalls, should be considered to both minimize off-site soil tracking and provide a stable access entrance surface. Placing geotextile fabric underneath the quarry spalls will provide greater stability if needed.  Silt fencing should be placed around appropriate portions of the site perimeter.  When not in use, soil stockpiles should be covered or otherwise protected to reduce the potential for soil erosion, especially during periods of wet weather.  Temporary measures for controlling surface water runoff, such as interceptor trenches, sumps, or swales, should be installed prior to beginning and concurrent with earthwork activities.  Surface water should not be directed to or dispersed over steeply sloped areas.  Dry soils disturbed during construction should be wetted to minimize dust and airborne soil erosion.  When appropriate, permanent planting or hydroseeding will help to stabilize site soils. Additional Best Management Practices, as specified by the project civil engineer and indicated on the plans, should be incorporated into construction activities. Temporary erosion control measures may be modified during construction as site conditions require, as approved by the site erosion control lead. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 12 Earth Solutions NW, LLC Stripping Topsoil was encountered generally within the upper four to eight inches, and root intrusions generally extended below the topsoil into the upper weathered soil. The organic-rich topsoil should be stripped and segregated into a stockpile for later use on site or to haul off site. The material remaining immediately below the topsoil may have some root zones and will likely be variable in composition, density, and/or moisture content. The material exposed after initial topsoil stripping will likely not be suitable for direct structural support as is and will likely need to either be compacted in place or stripped and stockpiled for reuse as fill; depending on the time of year stripping occurs, the soil exposed below the topsoil may be too wet to compact and may need to be aerated or treated. ESNW should observe initial stripping activities to provide recommendations regarding stripping depths and material suitability. In-situ and Imported Soils On-site soil exposed during site mass grading will likely consist of glacial till. The glacial till is moisture sensitive and may not be suitable for use as structural fill unless the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. If the on-site soils cannot be successfully compacted, cement treatment and/or the use of an imported soil may be necessary. In our opinion, a contingency should be provided in the project budget for export of soil that cannot be successfully compacted as structural fill if grading activities take place during periods of rainfall activity. We recommend avoiding construction-equipment tracking across the on-site soil and generally active site work during periods of heavy rainfall, as such disturbance has the potential to degrade the on-site soil beyond a workable state. Imported soil intended for use as structural fill should consist of a well-graded, granular soil with a moisture content that is at (or slightly above) the optimum level. During wet weather conditions, imported soil intended for use as structural fill should consist of a well-graded, granular soil with a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three-quarter-inch fraction). Wet Season Grading If grading takes place during the wetter, winter, spring, or early summer months, a contingency in the project budget should be included to allow for treatment of the on-site soils or export of on- site soils and import of structural fill as described below. Additional surface control and drainage measures will be necessary to control and detain runoff. Stormwater collection tanks may be necessary to detain stormwater. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 13 Earth Solutions NW, LLC Structural Fill Structural fill is defined as compacted soil placed in foundation, slab-on-grade, roadway, permanent slope, retaining wall, and utility trench backfill areas. Structural fill placed and compacted during site grading activities should meet the following specifications and guidelines:  Structural fill material Granular soil*  Moisture content At or slightly above optimum**  Relative compaction*** 95 percent (Modified Proctor)  Loose lift thickness (maximum) 12 inches * Existing soil may not be suitable for use as structural fill unless at (or slightly above) the optimum moisture content at the time of placement and compaction. ** Soil shall not be placed dry of optimum and should be evaluated by ESNW during construction. *** Relative compaction of 90 percent can be considered for mass grading activities. With respect to underground utility installations and backfill, local jurisdictions may dictate the soil type(s) and compaction requirements. Unsuitable material or debris must be removed from structural areas if encountered. Modular Block Walls and Rockeries Modular block walls and rockeries will be utilized to accommodate proposed grade transitions. In our opinion, the use of modular block walls and rockeries at this site is feasible from a geotechnical standpoint. ESNW can prepare engineered designs for the proposed modular block walls and rockeries. Excavations and Slopes Excavation activities across the site are likely to expose medium dense native soil within the upper approximately two to three feet bgs, transitioning into dense to very dense glacial till (“hardpan”) with depth. Based on the soil conditions observed at the subsurface locations, the following allowable temporary slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The applicable Federal Occupation Safety and Health Administration and Washington Industrial Safety and Health Act soil classifications are also provided:  Areas exposing groundwater seepage 1.5H:1V (Type C)  Loose soil 1.5H:1V (Type C)  Medium dense native soil 1H:1V (Type B)  Dense to very dense “hardpan” native soil 0.75H:1V (Type A) Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 14 Earth Solutions NW, LLC Permanent slopes should be planted with vegetation to enhance stability and to minimize erosion, and should maintain a gradient of 2H:1V or flatter. The presence of perched groundwater may cause localized sloughing of temporary slopes due to excess seepage forces. An ESNW representative should observe temporary and permanent slopes to confirm the slope inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope recommendations, as necessary. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. Foundations The proposed residential structures can be supported on conventional spread and continuous footings bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. Provided site earthwork activities are completed in accordance with our recommendations, suitable soil conditions should be exposed in building pad structural subgrade areas. Due to the high moisture sensitivity of the site soils, foundation subgrade areas should be protected from wet weather or areas of remediation should be anticipated; a layer of crushed rock can be considered to protect foundation subgrade areas. If structural building pads are disturbed during wet weather, remediation measures such as cement treatment or overexcavation and replacement with rock may be necessary in some areas. Provided the structures will be supported as described above, the following parameters can be used for design of the new foundations:  Allowable soil bearing capacity 2,500 psf  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40 The passive earth pressure and coefficient of friction values include a safety factor of 1.5. A one- third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. With structural loading as expected, total settlement in the range of one inch is anticipated, with differential settlement of about one-half inch. The majority of the settlements should occur during construction, as dead loads are applied. Seismic Design The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic design, specifically with respect to earthquake loads. Based on the soil conditions encountered at the exploration locations, the parameters and values provided below are recommended for seismic design per the 2018 IBC. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 15 Earth Solutions NW, LLC Parameter Value Site Class C* Mapped short period spectral response acceleration, SS (g) 1.278 Mapped 1-second period spectral response acceleration, S1 (g) 0.448 Short period site coefficient, Fa 1.200 Long period site coefficient, Fv 1.500 Adjusted short period spectral response acceleration, SMS (g) 1.534 Adjusted 1-second period spectral response acceleration, SM1 (g) 0.672 Design short period spectral response acceleration, SDS (g) 1.022 Design 1-second period spectral response acceleration, SD1 (g) 0.448 * Assumes very dense soil conditions, encountered to a maximum depth of six feet bgs during the October 2020 field exploration, remain very dense to at least 100 feet bgs. Based on our experience with the project geologic setting (glacial till) across the Puget Sound region, soil conditions are likely consistent with this assumption. Liquefaction is a phenomenon where saturated or loose soil suddenly loses internal strength and behaves as a fluid. This behavior is in response to increased pore water pressures resulting from an earthquake or another intense ground shaking. In our opinion, site susceptibility to liquefaction may be considered negligible. The composition and relatively dense characteristics of the native soil were the primary bases for this opinion. Slab-On-Grade Floors Slab-on-grade floors should be supported on a firm and unyielding subgrade consisting of competent native soil or at least 12 inches of new structural fill. Unstable or yielding areas of the subgrade should be recompacted or overexcavated and replaced with suitable structural fill prior to construction of the slab. A capillary break consisting of a minimum of four inches of free- draining crushed rock or gravel should be placed below the slab. The free-draining material should have a fines content of 5 percent or less defined as the percent passing the number 200 sieve, based on the minus three-quarters inch fraction. In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. If used, the vapor barrier should consist of a material specifically designed to function as a vapor barrier and should be installed in accordance with the manufacturer’s specifications. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 16 Earth Solutions NW, LLC Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters can be used for retaining wall design:  Active earth pressure (unrestrained condition) 35 pcf  At-rest earth pressure (restrained condition) 55 pcf  Traffic surcharge (passenger vehicles) 70 psf (rectangular distribution)  Passive earth pressure 300 pcf  Coefficient of friction 0.40  Seismic surcharge 8H* * Where H equals the retained height The passive earth pressure and coefficient of friction values include a safety factor of 1.5. Additional surcharge loading from adjacent foundations, sloped backfill, or other loads should be included in the retaining wall design. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design. Retaining walls should be backfilled with free-draining material that extends along the height of the wall, and a distance of at least 18 inches behind the wall; a drainage mat can be considered in lieu of the free-draining material. The upper one foot of the wall backfill can consist of a less permeable soil, if desired. A perforated drain pipe should be placed along the base of the wall, and connected to an approved discharge location. A typical retaining wall drainage detail is provided on Plate 3. Drainage The presence of groundwater seepage should be expected in excavations, especially in a perched condition at the contact between the weathered till and unweathered till soils, as well as at the contact between new structural fill and underlying native soil. Where zones of groundwater seepage are encountered, temporary measures to control groundwater seepage may be needed. Temporary measures to control groundwater seepage and surface water runoff during construction will likely involve passive elements such as interceptor trenches and sumps, as necessary. Surface water should not be directed to the top or toe of slopes, modular block walls, or rockeries; wall and rockery drainage should not be used to temporarily control surface water during construction. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 17 Earth Solutions NW, LLC Surface grades must be designed to direct water away from buildings. The grade adjacent to buildings should be sloped away from the buildings at a gradient of at least 2 percent for a horizontal distance of at least 10 feet or as setbacks allow. In our opinion, perimeter footing drains should be installed at or below the invert of the building footings. A typical footing drain detail is provided on Plate 4 of this report. If footing drains are not installed, we recommend backfilling footings with a relatively impermeable soil; native glacial till soils compacted to at least 90 percent will be relatively impermeable. If footing drains are omitted, there is a higher potential for moisture issues for slabs-on-grade or crawl space areas. If buildings will incorporate crawl spaces rather than slab-on-grade, in our opinion, a crawl space drain system can be used in lieu of perimeter footing drains. The crawl space drain must provide positive drainage to an appropriate outlet. Infiltration Evaluation The unweathered glacial till soil deposits observed at relatively shallow depths exhibit very poor soil infiltration characteristics. Additionally, moderately to steeply sloped areas are present within and adjacent to the site. Based on the observed soil conditions and sloped topography, we do not recommend utilizing infiltration systems such as trenches, dry wells, or infiltration ponds for the proposed development. On-site Stormwater Management Pursuant to City of Edmonds drainage design requirements, implementation of on-site stormwater BMPs are required for proposed developments in accordance with specified thresholds, standards, and lists. The intent of BMP implementation is to infiltrate, disperse, and retain stormwater runoff on site to the extent feasible. We understand the proposed residential development intends to add over 5,000 square feet of new hard surface and therefore must comply with Minimum Requirements (MRs) 1 through 9 of The 2014 SWMMWW. MR 5 concerns on-site stormwater management, and the viability of specific BMPs are to be evaluated for each type of proposed surface. The table below summarizes our evaluation of the required BMPs for MR 5, as outlined in The 2014 SWMMWW, from a geotechnical standpoint. It is instructed in The 2014 SWMMWW that BMPs are to be considered in the order listed (from top to bottom) for each surface type, and the first BMP that is determined to be viable should be used. For completeness, however, we have evaluated each listed BMP for the proposed surface types. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 18 Earth Solutions NW, LLC BMP Viable? Limitations or Infeasibility Criteria Lawns and Landscaped Areas Post-construction soil quality and depth Yes Limitation: Considered infeasible on slopes greater than 33 percent. Roofs Full dispersion No Infeasibility: Not recommended due to steeply sloped topography and could create flooding or erosion impacts. Downspout full infiltration systems No Infeasibility: The dense unweathered till soils observed at relatively shallow depths exhibit very poor soil infiltration characteristics. Additionally, steeply sloped topography is present. Bioretention or rain gardens No Infeasibility: Infiltration is not recommended due to shallow depth to impermeable soil and steeply sloped topography, which creates reasonable concerns about erosion or downgradient flooding. Downspout dispersion systems No Infeasibility: Not recommended due to steeply sloped topography. Perforated stub-out connections No Infeasibility: The dense unweathered till soils observed at relatively shallow depths would interfere with stub-out trenches, and steeply sloped topography is present. Other Hard Surfaces Full dispersion No Infeasibility: Not recommended due to steeply sloped topography and could create flooding or erosion impacts. Permeable pavement No Infeasibility: Infiltration is not recommended due to shallow depth to impermeable soil and steeply sloped topography, which creates reasonable concerns about erosion or downgradient flooding. Bioretention or rain gardens No Infeasibility: Infiltration is not recommended due to shallow depth to impermeable soil and steeply sloped topography, which creates reasonable concerns about erosion or downgradient flooding. Sheet flow dispersion No Infeasibility: Not recommended due to steeply sloped topography and could create flooding or erosion impacts. Concentrated flow dispersion No Infeasibility: Not recommended due to steeply sloped topography and could create flooding or erosion impacts. Note: Viability is stated from a geotechnical standpoint; available flowpaths and setbacks should also be evaluated by the storm designer. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 19 Earth Solutions NW, LLC Stormwater Vault Design We understand a stormwater vault is proposed for construction in the southwestern property corner. Vault foundations should be supported on competent native soil or crushed rock placed on competent native soil. Final storm vault designs must incorporate adequate buffer space from property boundaries such that temporary excavations to construct the vault structure can be successfully completed. Perimeter drains should be installed around the vault and conveyed to an approved discharge point. The presence of perched groundwater seepage should be anticipated during excavation activities for the vault. The following parameters can be used for stormwater vault design:  Allowable soil bearing capacity (dense native soil) 5,000 psf  Active earth pressure (unrestrained) 35 pcf  Active earth pressure (unrestrained, hydrostatic) 80 pcf  At-rest earth pressure (restrained) 55 pcf  At-rest earth pressure (restrained, hydrostatic) 100 pcf  Coefficient of friction 0.40  Passive earth pressure 300 pcf  Seismic surcharge 8H* * Where H equals the retained height The passive earth pressure and coefficient of friction values include a safety factor of 1.5. The vault walls should be backfilled with free-draining material or suitable sheet drainage that extends along the height of the walls. The upper one foot of the wall backfill can consist of a less permeable soil, if desired. A perforated drain pipe should be placed along the base of the wall and connected to an approved discharge location. If the elevation of the vault bottom is such that gravity flow to an outlet is not possible, the portion of the vault below the drain should be designed to include hydrostatic pressure. Design values accounting for hydrostatic pressure are included above. ESNW should observe grading operations for the vault and the subgrade conditions prior to concrete forming and pouring to confirm conditions are as anticipated, and to provide supplemental recommendations as necessary. Additionally, ESNW should be contacted to review final vault designs to confirm that appropriate geotechnical parameters have been incorporated. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 20 Earth Solutions NW, LLC We anticipate native soil will be used as vault backfill. The native soil is moisture sensitive and will settle once impacted by wet weather if placed below optimum moisture. We recommend placing the native soil at or slightly above optimum moisture. Native soil placed substantially above optimum moisture will require additional time or remediation prior to supporting a structure. Utility Support and Trench Backfill The soils observed at the subsurface locations are generally suitable for support of utilities. In general, the soils observed at the test locations will not be suitable for use as structural backfill in the utility trench excavations unless the soil is at or slightly above the optimum moisture content at the time of placement and compaction. If native soil is placed below optimum moisture levels, settlement will likely occur once wet weather impacts the trenches. Native soil will be difficult or impossible to use as utility trench backfill during wet weather conditions. Moisture conditioning or treatment of the soils may be necessary at some locations prior to use as structural fill. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable requirements of presiding jurisdiction. Preliminary Pavement Sections The performance of site pavements is largely related to the condition of the underlying subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted to the specifications detailed in the Site Preparation and Earthwork section of this report. Soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas of unsuitable or yielding subgrade conditions may require remedial measures, such as overexcavation and replacement with structural fill or thicker crushed rock sections, prior to pavement. For relatively lightly loaded pavements subjected to automobiles and occasional truck traffic, the following sections may be considered for preliminary design:  Two inches of hot-mix asphalt (HMA) placed over four inches of crushed rock base (CRB), or;  Two inches of HMA placed over three inches of asphalt-treated base (ATB). Main access drives and frontage improvement areas may require thicker pavement sections. The HMA, CRB, and ATB materials should conform to WSDOT specifications. City of Edmonds minimum pavement requirements may supersede the recommendations provided in this report. Due to the low permeability of the native soil, additional sub-pavement drainage, such as lateral drains connecting to catch basins, should be considered where inverted crown roadways are used. Pacific Ridge – DRH, LLC ES-7610.01 June 18, 2021 Page 21 Earth Solutions NW, LLC LIMITATIONS The recommendations and conclusions provided in this geotechnical engineering study are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the test locations may exist, and may not become evident until construction. ESNW should reevaluate the conclusions in this geotechnical engineering study if variations are encountered. Additional Services ESNW should have an opportunity to review the final design with respect to the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services during construction. Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drwn.MRS Checked AZS Date June 2021 Date 06/14/2021 Proj.No.7610.01 Plate 1 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutionsNWLLC Vicinity Map Bracket’s Reserve Edmonds,Washington Reference: Snohomish County,Washington OpenStreetMap.org NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. SITE Edmonds Shoreline Plate Proj.No. Date Checked By Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCTestPitLocationPlanBracket’sReserveEdmonds,WashingtonMRS AZS 06/16/2021 7610.01 2 NORTH 0 30 60 1 20 Scale in Feet1"=60' NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. LEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-7610.01,Oct.2020 Subject Site Existing Building Slope Stability Cross-Section TP-1 TP-1 TP-2 TP-3 TP-4 TP-5 240TH STREET S.W. 440 450 460 440 450 460 440450 450 450 450 460 460 440 440 Drwn.MRS Checked HTW Date June 2021 Date 06/17/2021 Proj.No.7610.01 Plate 3 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutionsNWLLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services Retaining Wall Drainage Detail Bracket’s Reserve Edmonds,Washington NOTES: Free-draining Backfill should consist of soil having less than 5 percent fines. Percent passing No.4 sieve should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free-draining Backfill,per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1-inch Drain Rock. LEGEND: Free-draining Structural Backfill 1-inch Drain Rock 18"Min. Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING Drwn.MRS Checked HTW Date June 2021 Date 06/17/2021 Proj.No.7610.01 Plate 4 Earth Solutions NWLLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services EarthSolutionsNWLLC EarthSolutionsNWLLC Footing Drain Detail Bracket’s Reserve Edmonds,Washington Slope Perforated Rigid Drain Pipe (Surround in Drain Rock) 18"Min. NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12"of less permeable,suitable soil.Slope away from building. LEGEND: Surface Seal:native soil or other low-permeability material. 1-inch Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING Earth Solutions NW, LLC Appendix A Subsurface Exploration Test Pit Logs ES-7610.01 The subsurface conditions at the site were explored by excavating five test pits at accessible locations on site. The test pits were completed on October 29, 2020. The approximate test pit locations are illustrated on Plate 2 of this report. The final logs represent the interpretations of the field logs and the results of laboratory analyses. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. GRAVEL AND GRAVELLYSOILS CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES WELL-GRADED SANDS, GRAVELLYSANDS, LITTLE OR NO FINES POORLY-GRADED SANDS,GRAVELLY SAND, LITTLE OR NO FINES SILTY SANDS, SAND - SILTMIXTURES CLAYEY SANDS, SAND - CLAYMIXTURES INORGANIC SILTS AND VERY FINESANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEYSILTS WITH SLIGHT PLASTICITY INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLYCLAYS, SANDY CLAYS, SILTY CLAYS,LEAN CLAYS ORGANIC SILTS AND ORGANICSILTY CLAYS OF LOW PLASTICITY INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND ORSILTY SOILS INORGANIC CLAYS OF HIGHPLASTICITY SILTSANDCLAYS MORE THAN 50% OF MATERIAL ISLARGER THANNO. 200 SIEVE SIZE MORE THAN 50%OF MATERIAL IS SMALLER THANNO. 200 SIEVESIZE MORE THAN 50%OF COARSEFRACTION PASSING ON NO.4 SIEVE MORE THAN 50%OF COARSEFRACTION RETAINED ON NO.4 SIEVE SOIL CLASSIFICATION CHART (APPRECIABLEAMOUNT OF FINES) (APPRECIABLE AMOUNT OF FINES) (LITTLE OR NO FINES) FINEGRAINEDSOILS SAND AND SANDY SOILS SILTS AND CLAYS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS PEAT, HUMUS, SWAMP SOILS WITHHIGH ORGANIC CONTENTS LETTERGRAPH SYMBOLSMAJOR DIVISIONS COARSE GRAINEDSOILS TYPICAL DESCRIPTIONS WELL-GRADED GRAVELS, GRAVEL -SAND MIXTURES, LITTLE OR NO FINES POORLY-GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLEOR NO FINES SILTY GRAVELS, GRAVEL - SAND - SILT MIXTURES CLEANGRAVELS GRAVELS WITH FINES CLEAN SANDS (LITTLE OR NO FINES) SANDS WITH FINES LIQUID LIMITLESS THAN 50 LIQUID LIMITGREATER THAN 50 HIGHLY ORGANIC SOILS DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Earth Solutions NW LLC 446.5 445.5 444.0 442.0 MC = 6.1%Fines = 16.4% MC = 4.3% MC = 4.7%Fines = 19.7% TPSL SM SM SM 1.5 2.5 4.0 6.0 Dark brown TOPSOIL (Fill) -roots Gray silty SAND with gravel, loose to medium dense, moist (Fill) Tan silty SAND with gravel, medium dense, moist [USDA Classification: very gravelly sandy LOAM] Gray silty SAND with gravel, dense, moist -weakly cemented [USDA Classification: gravelly sandy LOAM] -strongly cemented, very dense Test pit terminated at 6.0 feet below existing grade due to refusal on very dense till. Nogroundwater encountered during excavation. No caving observed. NOTES Depth of Topsoil & Sod 16": forest duff GROUND ELEVATION 448 ft LOGGED BY AZS EXCAVATION METHOD TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 10/29/20 COMPLETED 10/29/20 AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION ---SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-1 PROJECT NUMBER ES-7610.01 PROJECT NAME Bracket's Reserve GENERAL BH / TP / WELL - 7610-1.GPJ - GINT STD US.GDT - 6/18/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 461.4 459.5 458.0 MC = 13.0% MC = 4.5% MC = 6.6% TPSL SM SM 0.6 2.5 4.0 Dark brown TOPSOIL Tan silty SAND, loose to medium dense, moist Gray silty SAND with gravel, very dense, moist -strongly cemented Test pit terminated at 4.0 feet below existing grade due to refusal on very dense till. Nogroundwater encountered during excavation. No caving observed. NOTES Depth of Topsoil & Sod 8": moss GROUND ELEVATION 462 ft LOGGED BY AZS EXCAVATION METHOD TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 10/29/20 COMPLETED 10/29/20 AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION ---SAMPLE TYPENUMBERDEPTH(ft)0 PAGE 1 OF 1 TEST PIT NUMBER TP-2 PROJECT NUMBER ES-7610.01 PROJECT NAME Bracket's Reserve GENERAL BH / TP / WELL - 7610-1.GPJ - GINT STD US.GDT - 6/18/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 464.4 462.0 460.5 MC = 6.3% MC = 6.2%MC = 5.1% Fines = 6.0% TPSL SM SP-SM 0.6 3.0 4.5 Dark brown TOPSOIL, roots Brown silty SAND, loose to medium dense, moist Gray poorly graded SAND with silt and gravel, very dense, moist -strongly cemented [USDA Classification: very gravelly coarse SAND] Test pit terminated at 4.5 feet below existing grade due to refusal on very dense, cemented soil. No groundwater encountered during excavation. No caving observed. NOTES Depth of Topsoil & Sod 8": ivy GROUND ELEVATION 465 ft LOGGED BY AZS EXCAVATION METHOD TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 10/29/20 COMPLETED 10/29/20 AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION ---SAMPLE TYPENUMBERDEPTH(ft)0 PAGE 1 OF 1 TEST PIT NUMBER TP-3 PROJECT NUMBER ES-7610.01 PROJECT NAME Bracket's Reserve GENERAL BH / TP / WELL - 7610-1.GPJ - GINT STD US.GDT - 6/18/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 465.7 463.5 461.0 MC = 3.9% MC = 6.3% MC = 6.7% TPSL SM SM 0.3 2.5 5.0 Dark brown TOPSOIL, roots Brown silty SAND, loose to medium dense, moist Gray silty SAND with gravel, dense to very dense, moist -moderately cemented Test pit terminated at 5.0 feet below existing grade due to refusal on very dense till. Nogroundwater encountered during excavation. No caving observed. NOTES Depth of Topsoil & Sod 4": ivy GROUND ELEVATION 466 ft LOGGED BY AZS EXCAVATION METHOD TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 10/29/20 COMPLETED 10/29/20 AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION ---SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-4 PROJECT NUMBER ES-7610.01 PROJECT NAME Bracket's Reserve GENERAL BH / TP / WELL - 7610-1.GPJ - GINT STD US.GDT - 6/18/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 460.7 456.0 MC = 5.9% Fines = 8.6% MC = 4.3% MC = 5.7% TPSL SP- SM 0.3 5.0 Dark brown TOPSOIL Gray poorly graded SAND with silt and gravel, dense to very dense, moist -moderately cemented [USDA Classification: very gravelly loamy coarse SAND] Test pit terminated at 5.0 feet below existing grade due to refusal on very dense,cemented soil. No groundwater encountered during excavation. No caving observed. NOTES Depth of Topsoil & Sod 4": forest duff GROUND ELEVATION 461 ft LOGGED BY AZS EXCAVATION METHOD TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: CHECKED BY HTW DATE STARTED 10/29/20 COMPLETED 10/29/20 AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION ---SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-5 PROJECT NUMBER ES-7610.01 PROJECT NAME Bracket's Reserve GENERAL BH / TP / WELL - 7610-1.GPJ - GINT STD US.GDT - 6/18/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-7610.01 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER304 16.4 19.7 6.0 8.6 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Tan Very Gravelly Sandy Loam. USCS: SM with Gravel. USDA: Gray Very Gravelly Sandy Loam. USCS: SM with Gravel. USDA: Gray Very Gravelly Coarse Sand. USCS: SP-SM with Gravel. USDA: Gray Very Gravelly Loamy Coarse Sand. USCS: SP-SM with Gravel. 6 60 PERCENT FINER BY WEIGHTD10 0.234 0.184 0.712 0.456 2.874 1.772 3.902 3.714 GRAIN SIZE DISTRIBUTION 100 25.34 40.37 LL TP-01 TP-01 TP-03 TP-05 0.154 0.092 3/4U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 37.5 37.5 37.5 37.5 %Silt 0.84 0.61 TP-01 TP-01 TP-03 TP-05 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 3.0ft. 6.0ft. 4.5ft. 1.5ft. 3.00ft. 6.00ft. 4.50ft. 1.50ft. PL PROJECT NUMBER ES-7610.01 PROJECT NAME Bracket's Reserve GRAIN SIZE USDA ES-7610.01 BRACKETT RESERVE.GPJ GINT US LAB.GDT 6/14/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 Earth Solutions NW, LLC Appendix C Slope Stability Analysis ES-7610.01 1Distance (ft.)0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180Elevation (ft.)400410420430440450460470Bracket's ReserveExisting ConditionStaticColor Name Unit Weight(pcf)Effective Cohesion (psf)Effective Friction Angle (°)Cemented Glacial Till 130 500 38 4.1Distance (ft.)0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180Elevation (ft.)400410420430440450460470Bracket's ReserveExisting ConditionStaticColor Name Unit Weight(pcf)Effective Cohesion (psf)Effective Friction Angle (°)Cemented Glacial Till 130 500 38 6/15/2021 Bracket's Reserve, Existing, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Static - Bracket's Reserve, Existing, Static.html 1/4 Bracket's Reserve, Existing, Static Report generated using GeoStudio 2021. Copyright © 1991-2020 GEOSLOPE Internaonal Ltd. File Informaon File Version: 11.00 Created By: Henry Wright Last Edited By: Henry Wright Revision Number: 3 Date: 06/15/2021 Time: 02:06:57 PM Tool Version: 11.0.0.21118 File Name: Bracket's Reserve, Exisng Condion, Stac.gsz Directory: C:\Users\henry.wright\Documents\SlopeW\7610.01\ Last Solved Date: 06/15/2021 Last Solved Time: 02:06:58 PM Project Sengs Unit System: U.S. Customary Units Analysis Sengs Bracket's Reserve, Exisng, Stac Kind: SLOPE/W Method: Morgenstern-Price Sengs Side Funcon Interslice force funcon opon: Half-Sine PWP Condions from: (none) Unit Weight of Water: 62.430189 pcf Slip Surface Direcon of movement: Right to Le Use Passive Mode: No Slip Surface Opon: Entry and Exit Crical slip surfaces saved: 1 Opmize Crical Slip Surface Locaon: No Tension Crack Opon: (none) Distribuon F of S Calculaon Opon: Constant Advanced Geometry Sengs Minimum Slip Surface Depth: 3 Number of Slices: 30 Factor of Safety Convergence Sengs Maximum Number of Iteraons: 100 Tolerable difference in F of S: 0.001 Soluon Sengs Search Method: Root Finder Tolerable difference between starng and converged F of S: 3 6/15/2021 Bracket's Reserve, Existing, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Static - Bracket's Reserve, Existing, Static.html 2/4 Maximum iteraons to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Cemented Glacial Till Model: Mohr-Coulomb Unit Weight: 130 pcf Effecve Cohesion: 500 psf Effecve Fricon Angle: 38 ° Phi-B: 0 ° Slip Surface Entry and Exit Le Type: Range Le-Zone Le Coordinate: (3, 435.54) Le-Zone Right Coordinate: (107.10554, 464.84222) Le-Zone Increment: 8 Right Type: Range Right-Zone Le Coordinate: (117.89151, 468) Right-Zone Right Coordinate: (174, 468) Right-Zone Increment: 16 Radius Increments: 4 Slip Surface Limits Le Coordinate: (0, 435) Right Coordinate: (175, 468) Geometry Name: 2D Geometry Sengs View: 2D Element Thickness: 1 Points X Y Point 1 0 400 Point 2 0 435 Point 3 50 444 Point 4 70 450 Point 5 115 468 Point 6 175 468 Point 7 175 400 Regions Material Points Area Region 1 Cemented Glacial Till 2,3,4,5,6,7,1 9,650 ² 6/15/2021 Bracket's Reserve, Existing, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Static - Bracket's Reserve, Existing, Static.html 3/4 Slip Results Slip Surfaces Analysed: 692 of 765 converged Current Slip Surface Slip Surface: 268 Factor of Safety: 4.1 Volume: 962.2452 ³ Weight: 125,091.88 lbf Resisng Moment: 9,575,197.5 lbf· Acvang Moment: 2,355,414.8 lbf· Resisng Force: 131,362.55 lbf Acvang Force: 32,321.944 lbf Slip Rank: 1 of 765 slip surfaces Exit: (43.080805, 442.75454) Entry: (124.90507, 468) Radius: 65.91572 Center: (69.217385, 503.26703) Slip Slices X Y PWP Friconal Strength Cohesive Strength Sucon Strength Base Material Slice1 44.234004442.282120 psf 122.89414 psf 500 psf 0 psf CementedGlacial Till Slice2 46.540402441.387080 psf 275.55385 psf 500 psf 0 psf CementedGlacial Till Slice 3 48.846801 440.58968 0 psf 420.6093 psf 500 psf 0 psf Cemented Glacial Till Slice 4 51.428571 439.81438 0 psf 590.94325 psf 500 psf 0 psf Cemented Glacial Till Slice5 54.285714439.081550 psf 781.84781 psf 500 psf 0 psf CementedGlacial Till Slice6 57.142857438.482960 psf 953.56778 psf 500 psf 0 psf CementedGlacial Till Slice 7 60 438.0149 0 psf 1,103.5252 psf 500 psf 0 psf Cemented Glacial Till Slice 8 62.857143 437.67458 0 psf 1,229.936 psf 500 psf 0 psf Cemented Glacial Till Slice9 65.714286437.460010 psf 1,331.9122 psf 500 psf 0 psf CementedGlacial Till Slice10 68.571429437.369960 psf 1,409.4622 psf 500 psf 0 psf CementedGlacial Till Slice 11 71.40625 437.40269 0 psf 1,477.9999 psf 500 psf 0 psf Cemented Glacial Till Slice 12 74.21875 437.55646 0 psf 1,538.5159 psf 500 psf 0 psf Cemented Glacial Till Slice13 77.03125437.831420 psf 1,578.1639 psf 500 psf 0 psf CementedGlacial Till Slice14 79.84375438.229110 psf 1,598.9438 psf 500 psf 0 psf CementedGlacial Till Slice 15 82.65625 438.7518 0 psf 1,603.0042 psf 500 psf 0 psf Cemented Glacial Till Slice 16 85.46875 439.40257 0 psf 1,592.478 psf 500 psf 0 psf Cemented Glacial Till 6/15/2021 Bracket's Reserve, Existing, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Static - Bracket's Reserve, Existing, Static.html 4/4 Slice 17 88.28125 440.1854 0 psf 1,569.3455 psf 500 psf 0 psf Cemented Glacial Till Slice 18 91.09375 441.10527 0 psf 1,535.3271 psf 500 psf 0 psf Cemented Glacial Till Slice19 93.90625442.168410 psf 1,491.8018 psf 500 psf 0 psf CementedGlacial Till Slice 20 96.71875 443.38246 0 psf 1,439.745 psf 500 psf 0 psf Cemented Glacial Till Slice 21 99.53125 444.75684 0 psf 1,379.6767 psf 500 psf 0 psf Cemented Glacial Till Slice 22 102.34375 446.30319 0 psf 1,311.6095 psf 500 psf 0 psf Cemented Glacial Till Slice23 105.15625448.036020 psf 1,234.9841 psf 500 psf 0 psf CementedGlacial Till Slice 24 107.96875 449.97359 0 psf 1,148.5769 psf 500 psf 0 psf Cemented Glacial Till Slice 25 110.78125 452.13932 0 psf 1,050.3556 psf 500 psf 0 psf Cemented Glacial Till Slice 26 113.59375 454.56384 0 psf 937.24858 psf 500 psf 0 psf Cemented Glacial Till Slice27 116.23813457.106360 psf 774.55219 psf 500 psf 0 psf CementedGlacial Till Slice 28 118.7144 459.7767 0 psf 559.00189 psf 500 psf 0 psf Cemented Glacial Till Slice 29 121.19067 462.77504 0 psf 315.98414 psf 500 psf 0 psf Cemented Glacial Till Slice 30 123.66694 466.18212 0 psf 35.19503 psf 500 psf 0 psf Cemented Glacial Till 1.9Distance (ft.)0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180Elevation (ft.)400410420430440450460470Bracket's ReserveExisting ConditionSeismicColor Name Unit Weight(pcf)Effective Cohesion (psf)Effective Friction Angle (°)Cemented Glacial Till 130 500 38 6/15/2021 Bracket's Reserve, Existing, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Seismic - Bracket's Reserve, Existing, Seismic.html 1/4 Bracket's Reserve, Existing, Seismic Report generated using GeoStudio 2021. Copyright © 1991-2020 GEOSLOPE Internaonal Ltd. File Informaon File Version: 11.00 Created By: Henry Wright Last Edited By: Henry Wright Revision Number: 6 Date: 06/15/2021 Time: 02:09:48 PM Tool Version: 11.0.0.21118 File Name: Bracket's Reserve, Exisng Condion, Seismic.gsz Directory: C:\Users\henry.wright\Documents\SlopeW\7610.01\ Last Solved Date: 06/15/2021 Last Solved Time: 02:09:49 PM Project Sengs Unit System: U.S. Customary Units Analysis Sengs Bracket's Reserve, Exisng, Seismic Kind: SLOPE/W Method: Morgenstern-Price Sengs Side Funcon Interslice force funcon opon: Half-Sine PWP Condions from: (none) Unit Weight of Water: 62.430189 pcf Slip Surface Direcon of movement: Right to Le Use Passive Mode: No Slip Surface Opon: Entry and Exit Crical slip surfaces saved: 1 Opmize Crical Slip Surface Locaon: No Tension Crack Opon: (none) Distribuon F of S Calculaon Opon: Constant Advanced Geometry Sengs Minimum Slip Surface Depth: 3 Number of Slices: 30 Factor of Safety Convergence Sengs Maximum Number of Iteraons: 100 Tolerable difference in F of S: 0.001 Soluon Sengs Search Method: Root Finder Tolerable difference between starng and converged F of S: 3 6/15/2021 Bracket's Reserve, Existing, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Seismic - Bracket's Reserve, Existing, Seismic.html 2/4 Maximum iteraons to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Cemented Glacial Till Model: Mohr-Coulomb Unit Weight: 130 pcf Effecve Cohesion: 500 psf Effecve Fricon Angle: 38 ° Phi-B: 0 ° Slip Surface Entry and Exit Le Type: Range Le-Zone Le Coordinate: (3, 435.54) Le-Zone Right Coordinate: (107.10554, 464.84222) Le-Zone Increment: 8 Right Type: Range Right-Zone Le Coordinate: (117.89151, 468) Right-Zone Right Coordinate: (174, 468) Right-Zone Increment: 16 Radius Increments: 4 Slip Surface Limits Le Coordinate: (0, 435) Right Coordinate: (175, 468) Seismic Coefficients Horz Seismic Coef.: 0.326 Geometry Name: 2D Geometry Sengs View: 2D Element Thickness: 1 Points X Y Point 1 0 400 Point 2 0 435 Point 3 50 444 Point 4 70 450 Point 5 115 468 Point 6 175 468 Point 7 175 400 6/15/2021 Bracket's Reserve, Existing, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Seismic - Bracket's Reserve, Existing, Seismic.html 3/4 Regions Material Points Area Region 1 Cemented Glacial Till 2,3,4,5,6,7,1 9,650 ² Slip Results Slip Surfaces Analysed: 707 of 765 converged Current Slip Surface Slip Surface: 57 Factor of Safety: 1.9 Volume: 2,183.1604 ³ Weight: 283,810.85 lbf Resisng Moment: 53,193,936 lbf· Acvang Moment: 27,580,967 lbf· Resisng Force: 275,883.87 lbf Acvang Force: 143,111.28 lbf Slip Rank: 1 of 765 slip surfaces Exit: (3, 435.54) Entry: (156.4661, 468) Radius: 184.65994 Center: (45.138536, 615.32776) Slip Slices X Y PWP FriconalStrength CohesiveStrength SuconStrength Base Material Slice 1 5.6111111 434.96775 0 psf 183.30856 psf 500 psf 0 psf Cemented Glacial Till Slice 2 10.833333 433.90178 0 psf 441.45657 psf 500 psf 0 psf Cemented Glacial Till Slice3 16.055556432.991580 psf 686.9387 psf 500 psf 0 psf CementedGlacial Till Slice4 21.277778432.234820 psf 914.27851 psf 500 psf 0 psf CementedGlacial Till Slice 5 26.5 431.62961 0 psf 1,117.7885 psf 500 psf 0 psf Cemented Glacial Till Slice 6 31.722222 431.17445 0 psf 1,292.2622 psf 500 psf 0 psf Cemented Glacial Till Slice7 36.944444430.868220 psf 1,433.63 psf 500 psf 0 psf CementedGlacial Till Slice8 42.166667430.71020 psf 1,539.456 psf 500 psf 0 psf CementedGlacial Till Slice 9 47.388889 430.69999 0 psf 1,609.1934 psf 500 psf 0 psf Cemented Glacial Till Slice 10 52.5 430.83157 0 psf 1,674.5483 psf 500 psf 0 psf Cemented Glacial Till Slice11 57.5 431.099070 psf 1,737.3592 psf 500 psf 0 psf CementedGlacial Till Slice12 62.5 431.502930 psf 1,770.9476 psf 500 psf 0 psf CementedGlacial Till Slice 13 67.5 432.04405 0 psf 1,779.4754 psf 500 psf 0 psf Cemented Glacial Till 6/15/2021 Bracket's Reserve, Existing, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Existing Condition, Seismic - Bracket's Reserve, Existing, Seismic.html 4/4 Slice 14 72.5 432.72367 0 psf 1,790.1402 psf 500 psf 0 psf Cemented Glacial Till Slice 15 77.5 433.54332 0 psf 1,805.5235 psf 500 psf 0 psf Cemented Glacial Till Slice16 82.5 434.504920 psf 1,806.8411 psf 500 psf 0 psf CementedGlacial Till Slice 17 87.5 435.61075 0 psf 1,798.1852 psf 500 psf 0 psf Cemented Glacial Till Slice 18 92.5 436.86349 0 psf 1,782.993 psf 500 psf 0 psf Cemented Glacial Till Slice 19 97.5 438.26626 0 psf 1,763.9563 psf 500 psf 0 psf Cemented Glacial Till Slice20 102.5 439.822660 psf 1,743.0032 psf 500 psf 0 psf CementedGlacial Till Slice 21 107.5 441.53683 0 psf 1,721.3278 psf 500 psf 0 psf Cemented Glacial Till Slice 22 112.5 443.41348 0 psf 1,699.4446 psf 500 psf 0 psf Cemented Glacial Till Slice 23 117.59163 445.49871 0 psf 1,598.5523 psf 500 psf 0 psf Cemented Glacial Till Slice24 122.77489447.805430 psf 1,417.8997 psf 500 psf 0 psf CementedGlacial Till Slice 25 127.95816 450.30716 0 psf 1,231.6126 psf 500 psf 0 psf Cemented Glacial Till Slice 26 133.14142 453.01295 0 psf 1,035.1969 psf 500 psf 0 psf Cemented Glacial Till Slice 27 138.32468 455.9332 0 psf 823.67425 psf 500 psf 0 psf Cemented Glacial Till Slice28 143.50794459.079960 psf 591.52817 psf 500 psf 0 psf CementedGlacial Till Slice 29 148.6912 462.46723 0 psf 332.60777 psf 500 psf 0 psf Cemented Glacial Till Slice 30 153.87447 466.11144 0 psf 39.986766 psf 500 psf 0 psf Cemented Glacial Till 12Distance (ft.)0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180Elevation (ft.)400410420430440450460470Bracket's ReserveProposed ConditionStaticColor Name Unit Weight (pcf)Effective Cohesion (psf)Effective Friction Angle (°)Cemented Glacial Till130 500 38Rockery 145 500 45 4.1Distance (ft.)0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180Elevation (ft.)400410420430440450460470Bracket's ReserveProposed ConditionStaticColor Name Unit Weight (pcf)Effective Cohesion (psf)Effective Friction Angle (°)Cemented Glacial Till130 500 38Rockery 145 500 45 6/15/2021 Bracket's Reserve, Proposed, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Static - Bracket's Reserve, Proposed, Static.html 1/5 Bracket's Reserve, Proposed, Static Report generated using GeoStudio 2021. Copyright © 1991-2020 GEOSLOPE Internaonal Ltd. File Informaon File Version: 11.00 Created By: Henry Wright Last Edited By: Henry Wright Revision Number: 10 Date: 06/15/2021 Time: 02:24:07 PM Tool Version: 11.0.0.21118 File Name: Bracket's Reserve, Proposed Condion, Stac.gsz Directory: C:\Users\henry.wright\Documents\SlopeW\7610.01\ Last Solved Date: 06/15/2021 Last Solved Time: 02:24:08 PM Project Sengs Unit System: U.S. Customary Units Analysis Sengs Bracket's Reserve, Proposed, Stac Kind: SLOPE/W Method: Morgenstern-Price Sengs Side Funcon Interslice force funcon opon: Half-Sine PWP Condions from: (none) Unit Weight of Water: 62.430189 pcf Slip Surface Direcon of movement: Right to Le Use Passive Mode: No Slip Surface Opon: Entry and Exit Crical slip surfaces saved: 1 Opmize Crical Slip Surface Locaon: No Tension Crack Opon: (none) Distribuon F of S Calculaon Opon: Constant Advanced Geometry Sengs Minimum Slip Surface Depth: 3 Number of Slices: 30 Factor of Safety Convergence Sengs Maximum Number of Iteraons: 100 Tolerable difference in F of S: 0.001 Soluon Sengs Search Method: Root Finder Tolerable difference between starng and converged F of S: 3 6/15/2021 Bracket's Reserve, Proposed, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Static - Bracket's Reserve, Proposed, Static.html 2/5 Maximum iteraons to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Cemented Glacial Till Model: Mohr-Coulomb Unit Weight: 130 pcf Effecve Cohesion: 500 psf Effecve Fricon Angle: 38 ° Phi-B: 0 ° Rockery Model: Mohr-Coulomb Unit Weight: 145 pcf Effecve Cohesion: 500 psf Effecve Fricon Angle: 45 ° Phi-B: 0 ° Slip Surface Entry and Exit Le Type: Range Le-Zone Le Coordinate: (3, 435.54) Le-Zone Right Coordinate: (108.17778, 465.27111) Le-Zone Increment: 8 Right Type: Range Right-Zone Le Coordinate: (119.39523, 465.5) Right-Zone Right Coordinate: (175, 456.5) Right-Zone Increment: 16 Radius Increments: 4 Slip Surface Limits Le Coordinate: (0, 435) Right Coordinate: (175, 456.5) Seismic Coefficients Horz Seismic Coef.: 0 Surcharge Loads Surcharge Load 1 Surcharge (Unit Weight): 250 pcf Direcon: Vercal Coordinates X Y 125 466.5 6/15/2021 Bracket's Reserve, Proposed, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Static - Bracket's Reserve, Proposed, Static.html 3/5 150 466.5 168 457.5 175 457.5 Geometry Name: 2D Geometry Sengs View: 2D Element Thickness: 1 Points X Y Point 1 0 400 Point 2 0 435 Point 3 50 444 Point 4 70 450 Point 5 115 468 Point 6 175 456.5 Point 7 175 400 Point 8 115 465 Point 9 118 465 Point 10 117 468 Point 11 150 465.5 Point 12 168 456.5 Point 13 118 465.5 Regions Material Points Area Region 1 Cemented Glacial Till 2,3,4,5,8,9,13,11,12,6,7,1 9,354.5 ² Region 2 Rockery 10,5,8,9,13 7.75 ² Slip Results Slip Surfaces Analysed: 644 of 765 converged Current Slip Surface Slip Surface: 258 Factor of Safety: 4.1 Volume: 859.61078 ³ Weight: 111,865.65 lbf Resisng Moment: 7,976,409.8 lbf· Acvang Moment: 1,940,224.3 lbf· Resisng Force: 118,894 lbf Acvang Force: 28,919.917 lbf Slip Rank: 1 of 765 slip surfaces Exit: (43.507019, 442.83126) Entry: (119.39523, 465.5) Radius: 60.534207 Center: (68.34705, 498.03419) 6/15/2021 Bracket's Reserve, Proposed, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Static - Bracket's Reserve, Proposed, Static.html 4/5 Slip Slices X Y PWP Friconal Strength Cohesive Strength Sucon Strength Base Material Slice 1 44.589182 442.36939 0 psf 122.17191 psf 500 psf 0 psf Cemented Glacial Till Slice 2 46.753509 441.49423 0 psf 270.72944 psf 500 psf 0 psf Cemented Glacial Till Slice3 48.917836440.714120 psf 412.16914 psf 500 psf 0 psf CementedGlacial Till Slice 4 51.25 439.97919 0 psf 571.51244 psf 500 psf 0 psf Cemented Glacial Till Slice 5 53.75 439.30041 0 psf 745.29661 psf 500 psf 0 psf Cemented Glacial Till Slice 6 56.25 438.73475 0 psf 902.92646 psf 500 psf 0 psf Cemented Glacial Till Slice7 58.75 438.278990 psf 1,042.119 psf 500 psf 0 psf CementedGlacial Till Slice 8 61.25 437.93063 0 psf 1,161.2172 psf 500 psf 0 psf Cemented Glacial Till Slice 9 63.75 437.68781 0 psf 1,259.2835 psf 500 psf 0 psf Cemented Glacial Till Slice 10 66.25 437.54925 0 psf 1,336.1157 psf 500 psf 0 psf Cemented Glacial Till Slice11 68.75 437.514230 psf 1,392.1941 psf 500 psf 0 psf CementedGlacial Till Slice 12 71.25 437.58258 0 psf 1,441.7224 psf 500 psf 0 psf Cemented Glacial Till Slice 13 73.75 437.75465 0 psf 1,485.4221 psf 500 psf 0 psf Cemented Glacial Till Slice 14 76.25 438.03132 0 psf 1,511.5929 psf 500 psf 0 psf Cemented Glacial Till Slice15 78.75 438.414070 psf 1,522.0872 psf 500 psf 0 psf CementedGlacial Till Slice 16 81.25 438.90495 0 psf 1,518.8116 psf 500 psf 0 psf Cemented Glacial Till Slice 17 83.75 439.50669 0 psf 1,503.6032 psf 500 psf 0 psf Cemented Glacial Till Slice 18 86.25 440.22275 0 psf 1,478.131 psf 500 psf 0 psf Cemented Glacial Till Slice19 88.75 441.057470 psf 1,443.8196 psf 500 psf 0 psf CementedGlacial Till Slice 20 91.25 442.01614 0 psf 1,401.7929 psf 500 psf 0 psf Cemented Glacial Till Slice 21 93.75 443.10529 0 psf 1,352.8311 psf 500 psf 0 psf Cemented Glacial Till Slice 22 96.25 444.33287 0 psf 1,297.3344 psf 500 psf 0 psf Cemented Glacial Till Slice23 98.75 445.708660 psf 1,235.2846 psf 500 psf 0 psf CementedGlacial Till Slice 24 101.25 447.24474 0 psf 1,166.1958 psf 500 psf 0 psf Cemented Glacial Till Slice 25 103.75 448.95623 0 psf 1,089.0423 psf 500 psf 0 psf Cemented Glacial Till Slice 26 106.25 450.86232 0 psf 1,002.1468 psf 500 psf 0 psf Cemented Glacial Till 6/15/2021 Bracket's Reserve, Proposed, Static file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Static - Bracket's Reserve, Proposed, Static.html 5/5 Slice 27 108.75 452.98785 0 psf 903.00107 psf 500 psf 0 psf Cemented Glacial Till Slice 28 111.25 455.36588 0 psf 787.97341 psf 500 psf 0 psf Cemented Glacial Till Slice29 113.75 458.041870 psf 651.80944 psf 500 psf 0 psf CementedGlacial Till Slice 30 116 460.73869 0 psf 502.35328 psf 500 psf 0 psf Cemented Glacial Till Slice 31 117.5 462.71219 0 psf 233.1734 psf 500 psf 0 psf Cemented Glacial Till Slice 32 118.69761 464.45399 0 psf -26.267769 psf 500 psf 0 psf Cemented Glacial Till 2.0Distance (ft.)0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180Elevation (ft.)400410420430440450460470Bracket's ReserveProposed ConditionSeismicColor Name Unit Weight (pcf)Effective Cohesion (psf)Effective Friction Angle (°)Cemented Glacial Till130 500 38Rockery 145 500 45 6/15/2021 Bracket's Reserve, Proposed, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Seismic - Bracket's Reserve, Proposed, Seismic.html 1/5 Bracket's Reserve, Proposed, Seismic Report generated using GeoStudio 2021. Copyright © 1991-2020 GEOSLOPE Internaonal Ltd. File Informaon File Version: 11.00 Created By: Henry Wright Last Edited By: Henry Wright Revision Number: 8 Date: 06/15/2021 Time: 02:22:34 PM Tool Version: 11.0.0.21118 File Name: Bracket's Reserve, Proposed Condion, Seismic.gsz Directory: C:\Users\henry.wright\Documents\SlopeW\7610.01\ Last Solved Date: 06/15/2021 Last Solved Time: 02:22:35 PM Project Sengs Unit System: U.S. Customary Units Analysis Sengs Bracket's Reserve, Proposed, Seismic Kind: SLOPE/W Method: Morgenstern-Price Sengs Side Funcon Interslice force funcon opon: Half-Sine PWP Condions from: (none) Unit Weight of Water: 62.430189 pcf Slip Surface Direcon of movement: Right to Le Use Passive Mode: No Slip Surface Opon: Entry and Exit Crical slip surfaces saved: 1 Opmize Crical Slip Surface Locaon: No Tension Crack Opon: (none) Distribuon F of S Calculaon Opon: Constant Advanced Geometry Sengs Minimum Slip Surface Depth: 3 Number of Slices: 30 Factor of Safety Convergence Sengs Maximum Number of Iteraons: 100 Tolerable difference in F of S: 0.001 Soluon Sengs Search Method: Root Finder Tolerable difference between starng and converged F of S: 3 6/15/2021 Bracket's Reserve, Proposed, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Seismic - Bracket's Reserve, Proposed, Seismic.html 2/5 Maximum iteraons to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Cemented Glacial Till Model: Mohr-Coulomb Unit Weight: 130 pcf Effecve Cohesion: 500 psf Effecve Fricon Angle: 38 ° Phi-B: 0 ° Rockery Model: Mohr-Coulomb Unit Weight: 145 pcf Effecve Cohesion: 500 psf Effecve Fricon Angle: 45 ° Phi-B: 0 ° Slip Surface Entry and Exit Le Type: Range Le-Zone Le Coordinate: (3, 435.54) Le-Zone Right Coordinate: (108.17778, 465.27111) Le-Zone Increment: 8 Right Type: Range Right-Zone Le Coordinate: (119.39523, 465.5) Right-Zone Right Coordinate: (175, 456.5) Right-Zone Increment: 16 Radius Increments: 4 Slip Surface Limits Le Coordinate: (0, 435) Right Coordinate: (175, 456.5) Seismic Coefficients Horz Seismic Coef.: 0.326 Surcharge Loads Surcharge Load 1 Surcharge (Unit Weight): 250 pcf Direcon: Vercal Coordinates X Y 125 466.5 6/15/2021 Bracket's Reserve, Proposed, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Seismic - Bracket's Reserve, Proposed, Seismic.html 3/5 150 466.5 168 457.5 175 457.5 Geometry Name: 2D Geometry Sengs View: 2D Element Thickness: 1 Points X Y Point 1 0 400 Point 2 0 435 Point 3 50 444 Point 4 70 450 Point 5 115 468 Point 6 175 456.5 Point 7 175 400 Point 8 115 465 Point 9 118 465 Point 10 117 468 Point 11 150 465.5 Point 12 168 456.5 Point 13 118 465.5 Regions Material Points Area Region 1 Cemented Glacial Till 2,3,4,5,8,9,13,11,12,6,7,1 9,354.5 ² Region 2 Rockery 10,5,8,9,13 7.75 ² Slip Results Slip Surfaces Analysed: 643 of 765 converged Current Slip Surface Slip Surface: 47 Factor of Safety: 2.0 Volume: 2,170.0872 ³ Weight: 282,227.58 lbf Resisng Moment: 51,153,469 lbf· Acvang Moment: 26,098,856 lbf· Resisng Force: 278,607.13 lbf Acvang Force: 142,206.19 lbf Slip Rank: 1 of 765 slip surfaces Exit: (3, 435.54) Entry: (151.6708, 464.6646) Radius: 175.89527 Center: (46.816518, 605.8904) 6/15/2021 Bracket's Reserve, Proposed, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Seismic - Bracket's Reserve, Proposed, Seismic.html 4/5 Slip Slices X Y PWP Friconal Strength Cohesive Strength Sucon Strength Base Material Slice 1 5.6111111 434.91073 0 psf 196.08827 psf 500 psf 0 psf Cemented Glacial Till Slice 2 10.833333 433.7357 0 psf 470.75714 psf 500 psf 0 psf Cemented Glacial Till Slice3 16.055556432.72610 psf 732.42531 psf 500 psf 0 psf CementedGlacial Till Slice 4 21.277778 431.87904 0 psf 974.72069 psf 500 psf 0 psf Cemented Glacial Till Slice 5 26.5 431.19216 0 psf 1,191.0067 psf 500 psf 0 psf Cemented Glacial Till Slice 6 31.722222 430.66358 0 psf 1,375.2514 psf 500 psf 0 psf Cemented Glacial Till Slice7 36.944444430.291860 psf 1,522.8399 psf 500 psf 0 psf CementedGlacial Till Slice 8 42.166667 430.076 0 psf 1,631.1696 psf 500 psf 0 psf Cemented Glacial Till Slice 9 47.388889 430.01544 0 psf 1,699.9261 psf 500 psf 0 psf Cemented Glacial Till Slice 10 52.5 430.10477 0 psf 1,761.6606 psf 500 psf 0 psf Cemented Glacial Till Slice11 57.5 430.337740 psf 1,818.9424 psf 500 psf 0 psf CementedGlacial Till Slice 12 62.5 430.71371 0 psf 1,845.6718 psf 500 psf 0 psf Cemented Glacial Till Slice 13 67.5 431.23359 0 psf 1,846.8265 psf 500 psf 0 psf Cemented Glacial Till Slice 14 72.5 431.89868 0 psf 1,850.3188 psf 500 psf 0 psf Cemented Glacial Till Slice15 77.5 432.710660 psf 1,859.2587 psf 500 psf 0 psf CementedGlacial Till Slice 16 82.5 433.67159 0 psf 1,855.2923 psf 500 psf 0 psf Cemented Glacial Till Slice 17 87.5 434.78401 0 psf 1,842.7667 psf 500 psf 0 psf Cemented Glacial Till Slice 18 92.5 436.05088 0 psf 1,825.205 psf 500 psf 0 psf Cemented Glacial Till Slice19 97.5 437.475690 psf 1,805.2449 psf 500 psf 0 psf CementedGlacial Till Slice 20 102.5 439.0625 0 psf 1,784.6539 psf 500 psf 0 psf Cemented Glacial Till Slice 21 107.5 440.81597 0 psf 1,764.3878 psf 500 psf 0 psf Cemented Glacial Till Slice 22 112.5 442.7415 0 psf 1,744.668 psf 500 psf 0 psf Cemented Glacial Till Slice23 116 444.175810 psf 1,727.9268 psf 500 psf 0 psf CementedGlacial Till Slice 24 117.5 444.82304 0 psf 1,571.9588 psf 500 psf 0 psf Cemented Glacial Till Slice 25 121.5 446.68431 0 psf 1,319.3975 psf 500 psf 0 psf Cemented Glacial Till Slice 26 127.5 449.6169 0 psf 1,259.9249 psf 500 psf 0 psf Cemented Glacial Till 6/15/2021 Bracket's Reserve, Proposed, Seismic file:///C:/Users/henry.wright/Documents/SlopeW/7610.01/Bracket's Reserve, Proposed Condition, Seismic - Bracket's Reserve, Proposed, Seismic.html 5/5 Slice 27 132.5 452.30234 0 psf 1,062.2627 psf 500 psf 0 psf Cemented Glacial Till Slice 28 137.5 455.20152 0 psf 847.98131 psf 500 psf 0 psf Cemented Glacial Till Slice29 142.5 458.327060 psf 611.4775 psf 500 psf 0 psf CementedGlacial Till Slice 30 147.5 461.69371 0 psf 346.45625 psf 500 psf 0 psf Cemented Glacial Till Slice 31 150.8354 464.05195 0 psf 120.9545 psf 500 psf 0 psf Cemented Glacial Till Earth Solutions NW, LLC Report Distribution ES-7610.01 EMAIL ONLY Pacific Ridge – DRH, LLC 17921 Bothell-Everett Highway, Suite 100 Bothell, Washington 98012 Attention: Mr. John Mirante Ms. Kellie Schwacha Ms. Diane Swiben EMAIL ONLY RAM Engineering, Inc. 16531 – 13th Avenue West, Suite A108 Lynnwood, Washington 98037 Attention: Mr. Rob Long, P.E.