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Home My WebLink AboutGEO2009-00083 for BLD2009-00780 - BLD Engineering / Geo-tech Reports - 10/7/2009 TO BE KEPT IN THE PARCEL FILE Geotechnical Report for Andrews Pole Building 12930 NE North Shore Road Parcel No. 32234 50 00049 Mason County, Washington October 7, 2009 Project#0978 Prepared For: Steven Andrews CLYDg 17950 50th Avenue S. AS STET Seattle, Washington 98188 Prepared By: /0/7(09 r s Envirotech Engineering °�F'�� ;�� 74 NE Hurd Road ss'U1VAt.ti�G Belfair, Washington 98528 Phone: 360-275-9374 Fax: 360-275-4789 TABLE OF CONTENTS 1.0 INTRODUCTION...........................................................................................................................1 1.1 PROJECT INFORMATION............................................................................................................... 1 1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK..................................................................... 1 2.0 SURFACE CONDITIONS..............................................................................................................3 2.1 GENERAL OBSERVATIONS............................................................................................................3 2.2 TOPOGRAPHY............................................................................................................................... 3 2.Z.1 Upslope Geomorphology and Water Bodies.......................................................................... 3 2.3 SURFACE DRAINAGE..................................................................................................................... 3 2.4 SLOPE AND EROSION OBSERVATIONS...........................................................................................4 3.0 SUBSURFACE INVESTIGATION.................................................................................................5 3.1 FIELD METHODS,SAMPLING AND FIELD TESTING........................................................................ 5 3.2 GENERAL GEOLOGIC CONDITIONS...............................................................................................5 3.3 SPECIFIC SUBSURFACE CONDTTIONS............................................................................................. 5 3.3.1 Groundwater......................................................................................................................... 6 3.4 SOILS TESTING.............................................................................................................................6 4.0 ENGINEERING ANALYSES,CONCLUSIONS AND RECOMMENDATIONS.........................7 4.1 BUILDING FOUNDATION RECOMMENDATIONS.............................................................................. 7 4.1.1 Bearing Capacity.................................................................................................................. 7 4.1.2 SettlemeW............................................................................................................................. 4.2 LATERAL EARTH PRESSURES........................................................................................................8 4.3 EARTHWORK CONSTRUCTION RECOMMENDATIONS....................................................................8 4.31 Excavation............................................................................................................................ 8 4.3.2 Placement and Compaction of Native Soils and Engineered Fill..........................................8 4.3.3 Retaining Wall Back f ll........................................................................................................ 9 4.3.4 Wet Weather Considerations.................................................................................................9 4.3.5 Building Pads...................................................................................................................... 10 4.4 SLOPE STABILITY....................................................................................................................... 10 4.4.1 Slope Stability Assessment and Analysis............................................................................. 12 4.4.2 Building and Footing Setbacks........................................................................................... 12 4.5 EROSION..................................................................................................................................... 13 4.S.1 Temporary Erosion Control................................................................................................ 13 4.5.2 Permanent Erosion Control................................................................................................ 14 4.6 SURFACE AND SUBSURFACE DRAINAGE...................................................................................... 14 4.6.1 Septic Drainfield Impacts.................................................................................................... 14 4.7 VEGETATION BUFFER AND CONSIDERATIONS............................................................................. 14 4.8 ON-SITE AND OFF-SITE IMPACTS............................................................................................... 15 4.9 SEISMIC CONSIDERATIONS AND LIQUEFACTION......................................................................... 15 4.9.1 Liquefaction........................................................................................................................ 15 5.0 CLOSURE.....................................................................................................................................16 Appendix A-Site Plan Appendix B-Geologic Map Appendix C-Soil Information(Soil Profile; Soil Logs: Well Reports) Appendix D-Slope Stability Input&Output Appendix E—Erosion Control 1.0 INTRODUCTION Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a single family residential property located on the 12000 block of North Shore Road, identified as parcel number 32234 50 00049, Mason County, Washington (Project). This parcel includes Lot 49, Lot 50 and Lot 51. As presented herein, this report includes information pertaining to the Project in this Introduction Section; observations of the property and surrounding terrain in the Surface Conditions Section; field methods and soil descriptions in the Subsurface Investigation Section; and, conclusions/ recommendations for foundation, settlement, earthwork construction, lateral earth pressures, slope stability, erosion control, drainage, vegetation, and seismic considerations in the Engineering Conclusions and Recommendations Section. An initial geotechnical evaluation of the Project was conducted by Envirotech with the property owner's representative on September 25, 2009. It was determined that a geotechnical report was required in order to support the planned development. During the site visit by Envirotech, surface and subsurface conditions were assessed. After completion of the field work and applicable Project research, Envirotech prepared this geotechnical report. 1.1 Project Information Information pertaining to the Project was provided by the proponent of the property during the geotechnical investigation. Other information, such as site observations and assumed parameters typical of this type of development were provided by Evirotech during the preparation of this report. The property currently consists of a cleared building pad, driveway, and a small mobile home on Lot 49 and Lot 50. A small shed structure is currently on Lot 51. The planned development consists of a 1-story pole building in order to protect the mobile home on Lot 50. Foundation construction is expected to consist of isolated footings per Mason County prescriptive pole building requirements. Approximate building footprint and other proposed features with relation to existing site conditions are illustrated on the Site Map provided in Appendix A of this report. 1.2 Purpose of Investigation and Scope of Work The purpose of this geotechnical investigation is to assess geological hazards, and evaluate the Project in order to provide geotechnical recommendations that should be implemented during development. The investigation included characterizing the general Project surface and subsurface conditions, and evaluating the suitability of the soils to support the planned site activities. In order to fulfill the purpose of investigation, the geotechnical program completed for the proposed improvements of the Project include: • Review project information provided by the Project owner and/ or owner's representative; • Conduct a site visit to document the site conditions that may influence the construction and performance of the proposed improvements; • Define general subsurface conditions of the site by observing subsoils within test pits Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page l NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 October 7.2009 and/ or cut banks, review geological maps for the general area, research published references concerning slope stability, and review water well reports from existing wells near the Project; • Collect bulk samples at various depths and locations; • Perform soils testing to determine selected index and/or engineering properties of the site soils; • Complete an engineering analysis supported by the planned site alterations, and the surface and subsurface conditions that were identified by the field investigation, soil testing, and applicable project research; and, • Establish conclusions based on findings, and make recommendations for foundations, drainage, slope stability, erosion control, earthwork construction requirements, and other considerations. Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 2 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph 360-275-9374 Mason County,Washington Fax: 360-275-4789 October 7,2009 2.0 SURFACE CONDITIONS Information pertaining to the existing surface conditions for the Project was gathered on September 25, 2009 by Michael Staten, geotechnical engineer with Envirotech. During the site visit, the type of geotechnical investigation was assessed, and site features were documented that may influence construction and slope stability. This Surface Conditions Section provides information on general observations, vegetation, topography, drainage and slope/ erosion conditions for the Project and surrounding areas that may impact the Project. 2.1 General Observations The property is accessed from North Shore Road, an existing paved roadway along Hood Canal. The Project is currently partially developed land as previously mentioned. Beyond the property, rural residential development exists. Vegetation on and near the Project consists primarily of older firs, madronas, and other trees and shrubbery common to this area of the Pacific Northwest. An aerial photo of the Project and immediate vicinity is provided on the following page. 2.2 Topography The topographic information provided in this section was extrapolated from a public lidar source, and incorporated observations and field measurements. Where necessary, slope verification included measuring slope lengths and inclinations with a cloth tape and sextant. See the Site Map in Appendix A and the Geological Map in Appendix B in this report for an illustration of general topography with respect to the planned development. Descending grades, adjacent to the south side of the existing building pad, average 43% with a vertical relief of over 70 feet. Isolated areas along the hillside, such as driveway cuts have slopes greater than 60%. 2.2.1 Upslope Geomorphology and Water Bodies Ascending grades are generally located to the north of the planned development. This slope has immediate grades averaging 37% with a vertical relief of about 100 feet. Isolated areas of about 52%were observed on the ascending slope. Immediate slope cuts from the building pad have nearly vertical grades between 5 feet and 14 feet. The upland area of the property is situated on a hillside. Additional geomorphology that is pertinent to both upslope and downslope areas are provided in the Subsurface Investigation Section of this report. Wheeler Lake is upslope from the property. However, this lake does not significantly influence the Project. This conclusion is based on topography and location of the water body. 2.3 Surface Drainage Stormwater runoff originating upslope from the anticipated development is expected to be minimal to moderate. Although some indications of drainage was observed on the driveway, significant scour,erosion or other indications of past drainage problems were not observed within Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 3 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 October 7. 2009 the immediate vicinity of the planned development. 2.4 Slope and Erosion Observations The slope grades near the Project signal a potential landslide or erosion hazard area. Some indicators that may suggest past slope movements include: • Outwash of sediments near the bottom of the slope, • Fissures, tension cracks, hummocky ground or stepped land masses on the face or top of the slope, and parallel to the slope, • Fine, saturated subsurface soils, • Old landslide debris, • Significant bowing or leaning trees, or, • Slope sloughing or calving. Although slightly leaning/ bowing trees, and some tension cracks were observed on the embankment side of the existing driveway in one location, significant mass wasting on the property or within the general vicinity of the Project were not observed. Indications of past landslides, current unstable slopes, deep-seated slope problems, or surficial slope failures were not observed during the site visit. turf : oe'E 4't4 a tt7t �y Ali 26 r 'r -22N Rs Pi •y- re~,'. i •y� 7 �4. 16 Soil Survey From USDA Natural Resources Conservation Service Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 4 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph 360-275-9374 Mason County,Washington Fax: 360-275-4789 October 7,2009 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the Project was primarily gathered on October 5, 2009 by Michael Staten, geotechnical engineer with Envirotech. Specific information on field methods, sampling, field testing,general geologic conditions, specific subsurface conditions, and results from soil testing are presented in this section of the report. Appendix C of this report includes pertinent information on subsurface conditions for the Project, such as subsoil cross- section(s),test pit log(s),and water well report(s).Applicable test pit locations are depicted on the Site Plan and Geologic Map provided in the appendix of this report. 3.1 Field Methods,Sampling and Field Testing Information on subsurface conditions for the Project was accomplished by examining soils within existing bank cut slopes of up to 14 feet within the vicinity of the property. Information on subsurface conditions also included reviewing geological maps representing the general vicinity of the project,and water well reports originating from nearby properties. One bulk sample was collected at the Project site at approximately 40 inches below the existing ground surface near the anticipated building location. The soil sample collected was secured and transported for possible laboratory testing. Envirotech measured the relative density of the near-surface in-situ soils by gauging the resistance of hand tools.Within testing locations, field testing results generally indicated medium dense soils in the upper 36 inches,and dense soils from 36 inches to the depth of terminous. 3.2 General Geologic Conditions In general, soils at the project are composed of materials from glacial advances. The geologic conditions as presented in the "Geologic Map of Washington," compiled by J. Eric Schuster, 2002 indicates Quaternary sediments, Q8. Quaternary sediments are generally unconsolidated deposits,and dominantly deposited from glacial drift,including alluvium deposits. This project is located within the Puget Lowland. Typically, "lower tertiary sedimentary rocks unconformably overlie the Crescent Formation."as revealed in the Geologic Map. Initial sedimentary rocks were formed from shales, sandstones and coal deposits from rivers. During the Quaternary period, the Puget Lowland was covered by numerous ice sheets,with the most recent being the Fraser glacier with a peak of approximately 14,000 years ago. Upon the glacial retreat, the landscape was formed by glacial erosion glacial drift deposits. According to the "Interactive Geologic Map, 1:100,000 Quadrangle," as depicted by the Department of Natural Resources,this Project consists mostly of advance outwash, Q.B. Advance Outwash is usually described as"glaciological sand and gravel and latchstring clay, silt,and sand deposited during the advance of glaciers; sandy units commonly thick, well sorted, and fine grained, with mterlayered coarser sand, gravel, and cobbles and silt rip-up lag deposits at their base;may contain no glacial sediments;generally overlain by till." 3.3 Specific Subsurface Conditions The following subsurface conditions are estimated descriptions of the Project subgrade utilizing Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 5 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 October 7,2009 information from the depth of penetration at all testing, sampling, observed and investigated locations. Soils for this project were primarily described utilizing the Unified Soil Classification System(USCS)and the Soil Conservation Service(SCS)descriptions. The Project is composed of native soils with indications fill. The fill is primarily located on Lot 49 at the driveway entrance to the building pad, and side-cast along portions of the driveway. Fill material is not expected to influence this Project. For engineering purposes, the soils consist of distinguishable layers,as presented below. Soils within the upper 14 feet of natural ground were observed to be low moisture. light brown silty sand(SM)with some gravel, silty gravel with sand(GM), and poorly-graded sand (SP)with some gravel. Pockets of gravel were also observed. Soils below the upper 14 feet layer are expected to be similar as the overlying layer, and extending to variable depths. Very dense glacial till is expected to be anywhere from 15 feet to 50 feet below the ground surface on this property. The relative densities of the soil are provided above in Section 3.1. Expanded and specific subsurface descriptions, other than what is provided in this section, are provided in the soil logs located in Appendix C of this report. According to the "Soil Survey of Mason County," by the United States Department of Agriculture, Soil Conservation Service, the site soils are described as Everett Gravelly Sandy Loam, Ek, with 15% - 30% slopes. However, slopes exceeding 30% were observed on the property. The soil designations are depicted in the aerial photograph in the Surface Conditions Section(Section 2.0)of this report. 3.3.1 Groundwater From the water well report(s)and knowledge of the general area,permanent groundwater is at least 100 feet directly below the property at the building pad location. Perched groundwater at shallow depths was not observed on-site, nor indicated on the well reports. 3.4 Soils Testing The soil samples obtained at the Project site during the field investigation were preserved and transported for possible laboratory testing. Visual classification of soils was performed in the field at all observed soil profiles. Visual classifications were performed in accordance with the American Standards for Testing and Materials(ASTM D2488). The general results from the visual classification are presented above in the Subsurface Conditions Section. Specifically,soils within the upper 10 feet in one testing location consisted of approximately 10% gravel, 70% sand-sized soils, and 20% silt with low plasticity. Minor variations observed during the visual classification of particle size content (i.e. gravel, sand, fines), or isolated pockets within the soil stratification were insignificant in relation to the overall engineering properties of the soil. Emvirotech Engineering Andrews Ceotechnical Report 74 NE Hurd Road page 6 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph 360-275-9374 Mason County,Washington Fax:360-275-4789 October 7,2009 4.0 ENGINEERING ANALYSES, CONCLUSIONS AND RECOMMENDATIONS The following sections present engineering analysis and recommendations for the proposed improvements of the Project. These recommendations have been made available based on the planned improvements as outlined in the Introduction Section of this report; general observations including drainage and topography as recapitulated in the Surface Conditions Section; and, soil/ geologic conditions that were identified from the geotechnical investigation that is summarized in the Subsurface Investigation Section. Engineering analysis and recommendations for the Project that is provided herein, includes pertinent information for building foundations, earthwork construction, slope stability, erosion control, drainage,vegetation and seismic considerations. 4.1 Building Foundation Recommendations Recommendations provided in this section account for the site development of a typical one-story pole building. The recommended allowable bearing capacities and settlements as presented below, consider the probable type of construction as well as the field investigation results by implementing practical engineering judgment within published engineering standards. Evaluations include classifying site soils based on observed field conditions and soil testing for this Project. After deriving conservative relative densities, unit weights and angles of internal friction of the in-situ soils, the Terzhagi ultimate bearing capacity equation was utilized for determining foundation width and depth. The frost penetration depth is not expected to extend beyond 12 inches below the ground surface for this Project under normal circumstances and anticipated design features. The soils on-site have low to moderate frost susceptible characteristics and should be used only to the extents provided in this report. 4.1.1 Bearing Capacity Existing in-situ soils for this Project indicates that the structure can be established on isolated footings. Foundations shall be established on relatively undisturbed native soil. Alternatively, foundations may be constructed on selective re-compacted native soil or compacted engineered fill as described in the Earthwork Construction Recommendations Section of this report. For a bearing capacity requirement of no more than 1500 psf, a minimum footing diameter of 2 feet shall be placed at a minimum of 4 feet below the existing ground surface. Deeper foundations are required if structural requirements prevail. Foundation recommendations are made available based on adherence to the remaining recommendations that are provided in this report. Alterations to the aforementioned foundation recommendations may be completed upon a site inspection by a geotechnical engineer after the foundation excavation is completed. 4.1.2 Settlement Total and differential settlement that a structure will undergo depends primarily on the subsurface conditions, type of structure, amount and duration of pressure exerted by the structure, reduction of pore water pressure, and in some instances, the infiltration of free Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 7 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason Countv. Washington Fax: 360-275-4789 October 7,2009 moisture. Based on the expected native soil conditions, anticipated development, and construction abides by the recommendations in this report, the assumed foundation system may undergo a maximum of 1.0 inch total settlement, and a maximum differential settlement of 0.75 inch. 4.2 Lateral Earth Pressures Lateral earth pressures exerted through the backfill of a retaining wall are dependent upon several factors including height of retained soil behind the wall, type of soil that is retained, degree of backfill compaction, slope of backfill, surcharges, hydrostatic pressures, earthquake pressures, and the direction and distance that the top of the wall moves. Significant retaining structures are not anticipated for this Project. If retaining walls are later planned for this Project, prescriptive requirements from the County should be adhered to. For retaining structures with a height exceeding County prescriptive requirements, additional design parameters must be accounted for in the retaining wall analysis, and recommendations should only be provided by a qualified engineer after the type of backfill is acquired, inclination of backfill slope is estimated, and the final wall height is determined. 4.3 Earthwork Construction Recommendations Founding material for building foundations shall consist of undisturbed native soils. Compacted engineered fill, or selective re-compacted native soils may be used to the extents provided in this Earthwork Construction Recommendations Section. The following recommendations include excavations, subgrade preparation,type of fill,and placement of fill for building foundations. 4.3.1 Excavation Excavation is recommended to remove any excessive organic content or other deleterious material, if present, beneath foundations and to achieve appropriate foundation depth. Additional sub-excavation will be required for this Project if the soils below the required foundation depth are loose, saturated, or otherwise incompetent due to inappropriate land disturbing, or excessive water trapped within foundation excavations prior to foundation construction. All soils below the bottom of the excavation shall be competent, and relatively undisturbed or properly compacted fill. If these soils are disturbed or deemed incompetent, re-compaction of these soils below the anticipated footing depth is necessary. Excavations shall be completely dewatered, compacted, and suitable before placement of additional native soil, engineered fill or structural concrete. It is suggested that foundation excavations are inspected by a geotechnical engineer or qualified professional in order to assess the bearing material prior to the placement of structural footings. 4.3.2 Placement and Compaction of Native Soils and Engineered Fill For engineered fill or disturbed native soils that will be utilized as fill material directly beneath foundations, observation and/ or geotechnical testing is required prior to foundation construction. The following placement and compaction requirements are necessary. Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 8 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 October 7,2009 For disturbed native soils or engineered fill beneath foundations, limits of compacted or re-compacted fill shall extend laterally from the bottom edge of the foundation at a rate of one foot for each foot of compacted or re-compacted fill beneath the foundation. See the illustration below. FO❑TING COMPACTED NATIVE SOILS OR ENGINEERED 1 FILL I UNDISTURBED SUBGRA1lE Both engineered fill and native soils used as compacted fill should be free of roots and other organics, rocks over 6 inches in size, or any other deleterious matter. Engineered fill should consist of the following gradation: U.S. Standard Sieve %Finer(by weight) 6" 100 3" 60— 100 No. 4 20—60 No. 200 0 - 8 Table 1 Partical Size Distribution of Engineered Fill Compaction shall be achieved in compacted lifts not to exceed 8 inches and 12 inches for native soils and engineered fill, respectively. Each lift should be uniformly compacted to at least 95%of the modified Proctor maximum dry density (ASTM D 1557) and within 3% of optimum moisture content. Each lift surface should be adequately maintained during construction in order to achieve acceptable compaction and inter-lift bonding. Temporary earth cuts and temporary fill slopes exceeding 4 feet in height should be limited to a slope of 1:1 (horizontal:vertical). Utility trenches or other confined excavations exceeding 4 feet should conform to OSHA safety regulations. 4.3.3 Retaining Wall Backfill As previously mentioned, significant retaining structures are not anticipated for this Project. However, if used, native soils may be used as retaining wall backfill for this Project. Backfill may also consist of engineered fill or borrow materials approved by a geotechnical engineer. Placement, compaction and extents of retaining wall backfill should also be specified by a geotechnical engineer or qualified professional. 4.3.4 Wet Weather Considerations Although the subsoil characteristics do not pose a great risk in regards to saturation, additional provisions may be required during prolonged wet weather. Every precaution Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 9 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 October 7,2009 should be made in order to prevent free moisture from saturating and ponding within excavations. If the bottom of excavations used for footing placement changes from a moist and dense characteristic as presented in this report to loose, saturated conditions, then these soils become unsuitable for foundation bearing material. If this situation occurs, a geotechnical engineer should be notified, or these soils should be completely removed and replaced with suitable compacted material as presented above. 4.3.5 Building Pads Building pad fill is not recommended for this Project. Additional geotechnical design considerations, such as location, depth, and amount of fill will be required if building pad fill is necessary. 4.4 Slope Stability Landslides are natural geologic processes, and structures near slopes possess an inherent risk of adverse settlement, sliding or structural damage due to these processes. Geotechnical engineering cannot eliminate these risks for any site with sloping grades because gravity is constantly inducing strain on the sloping soil mass. Excessive wet weather and/ or earthquakes will exacerbate these strains. Geotechnical engineering considers excessive wet weather and `design' earthquakes in order to provide an acceptable factor of safety for developing on or near sloping terrain for the current conditions. These factors of safeties are based on engineering standards such as defining engineering properties of the soil, topography, water conditions, seismic acceleration and surcharges. Surface sloughing or other types of surficial slope movements usually do not affect the deep- seated structural capability of the slope. However, excessive and/or repeated surficial slope movements, if not repaired, may represent a threat to the structural integrity of the slope. If this situation does arise, the slope shall be inspected by a geotechnical engineer. Subsequently, maintenance may be required in order to prevent the possibility of further surficial or deep seated slope movements that may be damaging to life and property. According to the Coastal Zone Atlas of Mason County, Washington, the Project is within and near terrain labeled `Stable' and `Unstable' regarding potential landslide activity. Recent landslides are designated near the property, but consist of different circumstances when compared to this Project. Stable slopes are generally not prone to landslides due to small grades and accommodating geology. Unstable slopes are considered unstable because of geology, groundwater, slope and/ or erosional factors. They include areas of landslides and talus too obscure to be individually mapped. A site specific analyses and recommendations concerning the slopes are presented herein. A Stability Map from the Coastal Zone Atlas for the general area of this Project is provided below. Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 10 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County. Washington Fax: 360-275-4789 October 7.2009 7 � V i Project Map from Washington State Department of Ecology Website According to the Resource Map from the Washington State Department of Natural Resources (DNR), the Project is within terrain labeled `highly unstable' and `highly erodible' relating to soils. DNR did indicate previous landslide activity near the Project. A Resource Map from the DNR website for the general area of this Project is provided )below: �7060DE 1706008 yT0a100� 2 2 16 P�]� roject +7M 8 yT06,E0 17-18-2 a Pn p.t 6e.as 1701 a 17W1 -! 7 tiY;. ;•}•.'is \ a _ �7� '70.w 'n.42 4 N Resource Map from Washington State Department of Natural Resources Website Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 11 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00W9 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 October 7,2009 4.4.1 Slope Stability Assessment and Analysis The Simplified Bishop Method, utilizing `STABLE' software, was used to analyze the static stability of the site slopes. Seismic conditions were estimated utilizing worst case scenario values from the static analysis, a quasi-static analysis coefficient of at least 0.15, and applying the applicable values to STABLE software. Various radii's and center points of the circle were automatically selected, and produced factor of safeties in a graphical and tabular format. Worst case scenario values were used in the slope stability analysis in regards to topography, surcharges, water content, internal friction and cohesion of the site soils. STABLE software has been repeatedly checked with manual calculations, and consistently proved to be a very conservative program. The following soil properties were used in the analysis, and are based on observed conditions, known geology, and/or published parameters: Upper Advance Outwash • Soil unit weight: 138 pcf • Angle of internal friction: 36 degrees • Cohesion: 0 psf Lower Glacial Till • Soil unit weight: 140 pcf • Angle of internal friction: 40 degrees • Cohesion: 400 psf Based on the slope stability analysis, a minimum factor of safety was determined to be 1.45 relative to static slope failures, and 0.96 with relation to seismic conditions. These factor of safeties were primarily limited to the face of over-steepened slopes, and do not reflect conditions where development is expected to occur. For this Project, at the location of the proposed development, minimum factor of safeties for static and dynamic conditions were estimated to be over 1.5 and 1.1, respectively. See the slope stability information in Appendix D for a depiction of input parameters and example of outputs. Unstable slopes, as delineated by the Departments of Ecology and Natural Resources, are generally depicted for this region. Landslides in this area are mostly due to convergences that experience significant surface and groundwater. Based on the lack of significant water on this property, and results of the aforesaid slope stability analysis, it is our opinion that the proposed development should occur in accordance with this geotechnical report. 4.4.2 Building and Footing Setbacks Because of the relatively small cut behind most of the planned development, and nature of both the soils and type of development, building setbacks are not required from the ascending slope. Provided that assumptions relating to construction occur and recommendations are Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 12 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 October 7,2009 followed as presented in this report,the factor of safety for slope stability is sufficient for a 15 feet footing setback from the face of the nearby descending slopes exceeding 40%. See the figure below and the Geologic Map in Appendix B for an illustration of the setbacks. STRUCTURE TOP OF SLOPE SLOPE FACE 1 I 15 FT MIN —� FOOTING The required setbacks may be reduced, if necessary. The setback may be decreased by extending the foundation an additional 1.5 feet in depth below the ground surface for every 5 feet of setback reduction. Other mitigation techniques may be utilized in order to reduce the required setback, and subsequently would require additional geotechnical studies. 4.5 Erosion Based on the USCS description of the Project soils,the surface soils are considered moderately erodible. Temporary and/ or permanent erosion control measures may be required for site development. Extents of temporary erosion control will mostly depend on the timeliness of construction,moisture content of the soil,and amount of rainfall during construction. Soil erosion typical to the existing site conditions and planned disturbance of the Project include wind-borne silts during dry weather, and sediment transport during prolonged wet weather. Sediment transport could be from stormwater runoff or tracking off-site with construction equipment. Erosion control measures may need to be employed if excessive erosion occurs or required by the County or other prevailing agencies. Sedimentation control should be adequate when utilizing the erosion control recommendations as presented herein together with implementing appropriate erosion controls with the degree of care as expected from a licensed contractor. Additional erosion control information and specifications may be found in the appropriate "Stormwater Management Manual for Western Washington," prepared by the Washington State Department of Ecology Water Quality Program. 4.5.1 Temporary Erosion Control Erosion control during construction should include minimizing the removal of vegetation to the least extent possible. If necessary, erosion control measures during construction may include stockpiling cleared vegetation,silt fencing,intercepting swales,berms, straw bales, plastic cover or other standard controls. If necessary, Silt fencing is presented in this report as the first choice for temporary erosion control. Any erosion control should be located down-slope and beyond the limits of construction and clearing of vegetation where surface water is expected to flow. If the loss of sediments appears to be greater than expected, or erosion control measures are not functioning as needed, additional measures must be implemented immediately. See Appendix E for sketches and general Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 13 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 October 7,2009 notes regarding selected erosion control measures. The Site Map in Appendix A depicts the recommended locations for erosion control facilities to be installed,if necessary. 4.5.2 Permanent Erosion Control Permanent erosion control may also be necessary if substantial vegetation has not been established within disturbed areas upon completion of the Project. Temporary erosion control should remain in place until permanent erosion control has been established. Permanent erosion control may include promoting the growth of vegetation within the exposed areas by mulching,seeding or an equivalent measure. Selected recommendations for permanent erosion control are provided in Appendix E. Additional erosion control measures that should be performed include routine maintenance and replacement, when necessary, of permanent erosion control, vegetation, drainage structures and/or features. The following Surface and Subsurface Drainage Section may have additional recommendations with relation to permanent erosion for surface drainage features. 4.6 Surface and Subsurface Drainage Positive drainage should be provided in the final design for all planned residential buildings. Drainage shall include sloping the ground surface, driveways and sidewalks away from the Project structures. All constructed surface and subsurface drains should be adequately maintained during the life of the structure. If drainage problems occur during or after construction, additional engineered water mitigation will be required. This may include a combination of swales, berms, drain pipes, infiltration facilities, or outlet protection in order to divert water away from the structures to an appropriate protected discharge area. From a geotechnical perspective, both perimeter footing drains and roof drains are optional for the single family residence. If roof drains are not utilized, splash blocks should be placed at all downspouts. If storm water is collected from roof drains,the outlet shall be located either beyond toes of any slope exceeding 40%, or above ground outlets beyond the recommended building setbacks or vegetation buffers that are provided in this report. 4.6.1 Septic Drainfield Impacts On-site septic drainfields are not planned for this Project. 4.7 Vegetation Buffer and Considerations Vegetation is an excellent measure to minimize surficial slope movements and erosion on slope faces and exposed surfaces. By removing trees, the root strength is decreased over time, thereby lowering the `apparent' cohesion of the soil. Transpiration is decreased, which results in additional groundwater, increased pore water pressure and less cohesion/ friction of the soil particles. Stormwater runoff also increases, and, fewer plants will create less absorption of the force from raindrops,thereby creating the potential for erosion hazards. Vegetation shall not be removed from the face of the steep slope. However, any tree deemed hazardous to life or property shall be removed. If tree removal is necessary,then stumps and roots shall remain in place, and the underbrush and soil shall remain undisturbed as much as possible. Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 14 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph 360-275-9374 Mason County,Washington Fax: 360-275-4789 October 7,2009 Any disturbed soil shall be graded and re-compacted in order to restore the terrain similar to pre- existing conditions and drainage patterns. See the Geologic Map in Appendix B of this report for a depiction of the vegetation buffer. 4.8 On-Site and Off-Site Impacts From a geotechnical position, it is Envirotech's opinion that the subject property and adjacent properties to the proposed development should not be significantly impacted if all recommendations in this report are followed. This is based on the expected site development, existing topography, land cover,and the recommendations presented in this report. 4.9 Seismic Considerations and Liquefaction Soils immediately below the expected foundation depth for this Project are generally Type D, corresponding to the International Building Code (IBC) soil profiles. According to the IBC, the regional seismic zone is 3 for this Project. The estimated peak ground acceleration ranges from 0.50g to 0.60g. This estimation is based on the United States Geological Survey(USGS)National Seismic Hazard Project in which there is an estimated 2% probability of exceedance within the next 50 years. There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this property is the Tacoma Fault Zone, in which the distal end is approximately 4 miles to the northeast of this Project. This information is based on the USGS Quaternary Fault and Fold Database for the United States. 4.9.1 Liquefaction The potential for liquefaction is believed to be low for this Project. This is based, in part, on the subsurface conditions such as soil characteristics and the lack of a permanent shallow water table. Subgrade characteristics that particularly contribute to problems caused from liquefaction include submerged, confined, poorly-graded granular soils (i.e. gravel, sand, silt). Although gravel-and silt-sized soil particles could be problematic, fine and medium grained sands are typically subjected to these types of seismic hazards. No significant saturated sand stratifications are anticipated to be within the upper 50 feet of the subsoil for this Project. Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 15 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 October 7,2009 5.0 CLOSURE Based on the project information and site conditions as presented in this report, it is Envirotech's opinion that additional geotechnical studies are not required to further evaluate this Project. Due to the inherent natural variations of the soil stratification and the nature of the geotechnical subsurface exploration, there is always a possibility that soil conditions encountered during construction are different than those described in this report. Therefore, it is recommended that a qualified engineer observes and documents the construction, or Envirotech is promptly notified if project and subsurface conditions found on-site are not as presented in this report so that we can re-evaluate our recommendations. This report presents geotechnical design guidelines, and is intended only for the owner, or owners' representative, and location of project described herein. This report should not be used to dictate construction procedures or relieve the contractor of his responsibility. Any and all content of this geotechnical report is only valid in conjunction with the compliance of all recommendations provided in this report. Semantics throughout this report such as `shall,' `should' and `recommended' imply that the correlating design and/or specifications must be adhered to in order to protect life and property. Semantics such as `suggested' or `optional' refer that the associated design or specification may or may not be performed. The recommendations provided in this report are valid for the proposed development at the issuance date of this report. Changes to the site other than the expected development, changes to ordinances or regulatory codes, or broadening of accepted geotechnical standards may affect the conclusions and recommendations of this report. The services described in this report were prepared under the responsible charge of Michael Staten, a professional engineer with Envirotech. Michael Staten has appropriate education and experience in the field of geotechnical engineering in order to assess landslide hazards, earthquake hazards,and general soil mechanics. Please contact Michael Staten at 360-275-9374 if you have any questions, comments, or require additional information. Sincerely, Envirotech Engineering Michael Staten,P.E. Geotechnical Engineer Envirotech Engineering Andrews Geotechnical Report 74 NE Hurd Road page 16 NE North Shore Road Belfair,Washington 98528 Parcel 32234 50 00049 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 October 7,2009 APPENDIX A SITE PLAN SCALE, I INCH = 50 FEE 0 25 50 APPRX L❑CATION OF PROPOSED POLE APPRXti2p BUILDING LOCATION OF �r> EXISTING M ¢ MOBILE HOME �p 150FT± TP AP RX LE%IDEIN OF EX TING HED xx x v �p0 BUILDING PAD TEMP❑RA Y EROSION CONTROL, IF NECESSARY +i > �p o LOT 49 LOT 50 L T 1 (U �0 APPRX CATION OF LEXISTIN DRIVEWAY �Tp p�0 NE NORTH SHORE ROAD ❑N-SITE SEPTIC SYSTEMS ARE NOT PLANNED FOR THIS PROJECT PROJECT/ OWNER/ LOCATION- SINGLE FAMILY RESIDENCE NOTES 1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. GENERAL LOCATIONS GE❑TECHNICAL REPORT ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE ANDREWS GEOTECHNICAL REPORT. PARCEL 32234 50 0D049 2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. LEGEND MASON COUNTY, WASHINGTON CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL TEMPORARY ENGINEER, REPORT' f+ +EROSION CONTROL ENVIROTECH ENGINEERING 3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATION OF 74 NE HURD ROAD PROPERTY LIDS AND SITE FEATURES, SUCH AS TOP OF SLOPES, WATER SLOPE INDICATOR BELFAIR, WASHINGTON 98528 FEATURES, ETC.., WITH RELATION TO THE PROPERTY LINES MUST BE 360-275-9374 VERIFIED BY THE OWNER. RECOMMENDATIONS IN THIS REPORT PROVIDE 80 EXISTING CONTOUR SETBACKS, DEPTHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LI S. TPle TEST PIT SITE PLAN NE APPENDIX B GEOLOGIC MAP SOILS: MEDIUM DENSE SILTY SAND AND GRAVEL (SM-GM) ❑VERLYING N VERY DENSE CONGLOMERATE SCALE, I INCH = 50 FEE 0 25 0 APPRX LOCATION OF PROPOSED POLE APPRX% BUILDING L❑CATION OF EXISTING Q ~6' CUT MOBILE HOME 14' CUT %11pglPAREA OF AP�RX L❑C ATION OF SIGNIFICANT FIL EX TING HED x I 70% BUILDING PAD 15FT BUILDING T❑P ❑F SLOPE SETBACK (SEE EXCEEDING 40% REPORT) Q �p -- o LOT 49 LOT 50 L T 1 of �O APPRX CATION OF EXISTIN DRIVEWAY P1 APPROXIMATE TOE OF �p SLOPE EXCEEDING 40% VEGETATION SHALL NOT BE NE NORTH SHORE ROAD REMOVED ON THE FACE BF SLOPES EXCEEDING 40% UNLESS PERMITTED BY GE❑TECHNICAL REPORT PROJECT/ OWNER/ LOCATION- SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT NOTES 1. ALTERNATIVES FOR REDUCING BUILDING SETBACKS OR VEGETATION ANDREWS BUFFERS MAY BE PROVIDED IN THE GEOTECHNICAL REPORT. PARCEL 32234 50 00049 2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. MASON COUNTY, WASHINGTON CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL LEGEND ENGINEER- REPORT• ENVIROTECH ENGINEERING 3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATION 74 NE HURD ROAD OF PROPERTY LINES AND SITE FEATURES, SUCH AS TOP OF SLOPES, WATER —� SLOPE INDICATOR 74LNEIH RD ROAD 98528 FEATURES, ETC.., WITH RELATION TO THE PROPERTY LINES MUST BE BE FA 5-9374 VERIFIED BY THE OWNER, RECOMMENDATIONS IN THIS REPORT PROVIDE 80 EXISTING CONTOUR SETBACKS, DEPTHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LINES. TPle TEST PIT GEOLOGIC MAP APPENDIX C SOIL INFORMATION VERTICAL AND HORIZONTAL SCALE. 1 INCH = 40 FEET 0 10 20 40 PROPOSED POLE BLD EXISTING DRIVEWAY EXISTING GRADE MED, DENSE TO DENSE EXISTING ADVANCE ❑UTWASH (SM, SP, DRIVEWAY GM, GP) LL NORTH SHORE ROAD VERY DENSE GLACIAL TILL SFCTION A-A PROJECT/ OWNER/ LOCATION, SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT ANDREWS PARCEL 32234 SO 00049 MASON COUNTY, WASHINGTON NOTES ENGINEER 1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENVIROTECH ENGINEERING POSITIVE DRAINAGE 74 NE HURD ROAD 2) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF R, WASHINGTON 96528 360-2 THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS. 60-275-9374 LOWER DEPTHS ARE BASED ON SITE GEOLOGY, WELL LOG(S), AND/OR EXPERIENCE IN THE GENERAL AREA. SOIL PROFILE TEST PIT LOG TEST PIT NUMBER TP-1 PROJECT: Single Family Residence Geotechnical Report DATE OF LOG: 10/5/2009 PROJECT NO: 0978 LOGGED BY: MCS CLIENT: Steve Andrews EXCAVATOR: N/A LOCATION: Parcel 32234 50 00049 DRILL RIG: None Mason County, Washington ELEVATION: N/A INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A STANDARD PENETRATION TEST SOIL STRATA, DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE AND TEST DATA DEPTH N 10 30 50 0 .... ....... ...................................... SM Light brown, low moisture SILTY SAND with some gravel, medium dense. Gravel is fine and subrounded. Sand is 2 well-graded. Low plasticity. 4 Dense 6 8 10 Excavation terminated at approximately 10.0 feet 12 14 16 18 20 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this boring and should not be Geotechnical Engineering interpreter/as being indicitive of the entire site. TEST PIT LOG TEST PIT NUMBER TP-2 PROJECT: Single Family Residence Geotechnical Report DATE OF LOG: 10/5/2009 PROJECT NO: 0978 LOGGED BY: MCS CLIENT: Steve Andrews EXCAVATOR: N/A LOCATION: Parcel 32234 50 00049 DRILL RIG: None Mason County, Washington ELEVATION: N/A INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A STANDARD PENETRATION TEST SOIL STRATA, DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE AND TEST DATA DEPTH IN10 30 50 0 . ............ ............ ..... ... . ............ .. ... GM Light brown, low moisture SILTY GRAVEL with SAND, medium dense. Gravel is fine and subrounded. Sand is 2 C well-graded. Low plasticity. Dense 4 18" layer of coarse poory-graded gravel 6 . ........I...................................... . .. SP Light brown, low moisture POORLY GRADED SAND with some gravel and a trace of silt. Gravel is fine and 8 subrounded. Non-plastic 7-10 Very dense 12 14 Excavation terminated at approximately 14.0 feet 16 18 20 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this boring and should not be Geotechnical Engineering interpreted as being indicitive of the entire site. 0 + Q 4 DEPARTMENT OF CONGRRVAT[ON . Wmx LOG N Date--- Record C o Location:State of WASGTON - �l �J`J�s s. i � Area na ir4;B.Tre ,- a� D 4MILU Co-atoicanwDr*ili . -ft-: -Orchard- Wet Addrm& O �_3� 8 _175 - �1 L Method of Madrona J ottjnkside C owner Bgacn K k .�- _..-------... C � Land surface: datum--ftb°°°�� -- ta _ -Dm - �+ crnn.�+n.ear■ If materSal...c.r-E..rS.i..o �r.e 1wd If d.pcL. Qern4h vltl[drattRU6 9. blow land-+vrfu.d.1ta raa .Wt. .at�Kirr�tlodl.yyryw;.te.)-' - ' - •- - If fpd3Mr Feaatrlss fart oR i j,po3e rShTs -cu - .2 12 ar pan -, ow ~' _ z ;. N -- - - 0 t� n ui C G L R 8hwt-_._—^r •nacre Twn up p _ rlla OriKlnal and Fint Ccrpy with Ayplic.uun No, f>rpanrnenl of Ern1r" WATER WELL REPORT 7econd pyy pOwnes'`CpyY &TAT6 O>E WABiI!>QVOTON permit Na .. (1) OWNER: Name...Hq.i Agues. Bergiluiat. ................................ Address..Stir...RL l .... _. _.._. .. L (2) LOCATION OF WELL: coaatyMason C lo Be ring and distance troth section or■ubdivirn corner ttet L Q 1raY� (3) PROPOSED USE: )e( 10 - WELL LAG: Domestic industrial [] Municipal ❑ ) !40 Irrigation Q Test Well ❑ Other ❑ Formation:o thteneDescribe sr o1 a4utyers color. a ke kind size nature of the mated+„each stratum penetrated, with at hest one entry jar each change of formation- . owner's number of well H (4) TYPE OF W4RK. fit mo than onel•• ....... ........ 11ATERIAL ]PEON I TO z New well Meth ad: Dus ❑d Bored ❑ grom..Elr y-i Br.��•a-hard- �.s Deepened O Cable 'r1- Driven -B = Reconditioned{] Rotary,❑ Jettelt 0 in 11 0 //-� � t;?ateL --- C (S) DIMENSIONS: Diameter of well . . :..1�..... _Q. Incas. ea>�ea--nQ eater _--- __50 0 Drilled........W�............ft. Daptb o!easnplatad'swL.........(.f•._ --N - �' _50L.-:---59 -- t0 (6) CONSTRUCTION DETAILS: Br ter hAA hg— '- Cali ft installed:.... ...:' Diem. tram .... .._. a. to _.. _ n. .1 — 402 Threaded❑ ......Dlsm.I gram .... ft.to ....:.........-It. Welded Perforations: Yes 0 No K l - - L Type of perforatod used.................:.:..:... ........................•....-............_.. . 0 SIZE of perforations ............._.............. in. by .......... .......... in. _ — � ......... _.. ._. pertoitatlona from ...................... ft. to _....__..---...... it. perforations tmn ..._.............. S.'tb .............. ...... perforations,from Screens: Ys❑ NoK -- 0 manufacturer's Name... ____.._.._..... _...._..-...__ _._ __� - - Q1Type--- ---.._......_,... ....._............._............. Model No.........__.w_.. Z Dlam_ Slot rise _.............from ._........_. ft. to_.........._..n. - Slot also....-.........from ... ...........ft. to .--: tt weer - r_ Gravel packed: Yes❑ No�( site of aravtl:................ _._.�_... _ t>. Gravel placed ttotit ---_.._....___:........_..!t.to.........................._.ft. _ Surface seal: It Yes� No�.1.�11s'To rYltat de ? ......A.._......_..._. . Material used In:seal..._5f�M=�.l_J-!.. ......................... _... Did any strata contain unusable water? ' ' Yes 0' -- QType of water?. -_...._....___...,........Depth�of strata...._......................... - Z ft" Method Of Nallrlt sVatl Olr_...............__ .........._.._..........._........ .�...... ---.- (7) PUMP: Manufacturer's Namefk 0 Type: .s.LC IQ. -teas,,e3 :.._... ._Hp..�IS _ - r _~ -- ____ Land-surface cites n ` ' ` � (8) WATER LEV EL?S' leee .><bpve mean sea .... ........... .... - C /� t O Static level _..._. .?.._� ........!R below top of well•-Date.....` 0 Artesian pressure ........... ..__......lbs.- er square inch Dow............ __::... ._.... - V Artesian water is controlled by............. ..._.........._....._.._...__.. LLJ vale, eteJ I O Drawdown la.omount water level is ---� {9) WELL TESTS; - work started >t ] lowered below static level Is7�. Completed..,J.ttr2e�••�2---•-•� 1 ••- 3. r_ Was a pump test made? Yes Q No VLIf Yes.by whom?... ........._. .........' 49 Yield: SaL/min. with ft. drawfturn after tin rt 1s . •WELL DRILLERS, STATEMENT: This well was drilled under my jurisdiction and this repo L true to the best of my knowledge and belief. R Q, Recovery data itlnie taken as zero.when pulnD fumed o!<) (water level - . measured gram well tot,to water level) NAME.......IRSeb.R..l�ri l��tlp,..�iQ1�1- _....... ... ........... _........ 0 rime Water fsvet :,TEme Water Levi Tina Wate* Level (person, firm,or corporation) (Type or print) a Addresa._..1653._Sa.._95th Tacoma...LTb..38G+4 ............... .. ...................... 4�� / -- ........ ......... Date of test �)/� [Sisftedl•-- ....... ..... .... .. _.�.....It.drewdown after_ _.... ........ n. ' (V►ell Driller) Barter test.J2 ..... f:allenin.w1th..t72.. Artesiannow........_.... ..................................s.p m. Date.-......_........................-......... Temperature of water.............. Was a cbemlcal analYsls made?Yes Q No Wcerrse No..... y. ..................... Date-...IIu1e..13......----.., 10-79--- Pk (USE ADDITIONAL SHEETS Ir NECESSARY) low e ECY 050•.1.20 APPENDIX D SLOPE STABILITY STABLE Slope Stability Analysis System New User Project : Andrews Datafile: Dynamic Bishop STABLE Version 9.03.00u Bishop TITLE Dynamic UNITS (Metric/Imperial) = I GEOMETRY DEFINITION POINTS NO. X Y 1 0.000 0.000 2 50.000 -18.550 3 50.000 -24.540 4 93.000 -24.540 5 105.600 -32.000 6 117.000 -32.000 7 192.000 -64.000 8 225.000 -64.000 9 285.000 -100.000 10 310.000 -100.000 11 0.000 -62.000 12 310.000 -114.000 13 31.000 -11.500 14 44.050 -16.340 15 57.110 -24.540 16 70.160 -24.540 17 83.210 -24.540 18 96.260 -26.570 19 109.320 -32.000 20 122.370 -34.290 21 135.420 -39.860 22 148.470 -45.430 23 161.530 -51.000 24 174.580 -56.570 25 187.630 -62.140 26 200.680 -64.000 27 213.740 -64.000 28 226.790 -65.070 29 239.840 -72.910 30 252.890 -80.740 31 265.950 -88.570 32 279.000 -96.400 LINES Lo X Hi X SOIL 1 2 1 2 3 1 3 4 1 4 5 1 5 6 1 6 7 1 7 8 1 STABLE®2002 MZ Associates Ltd Printed on: 09/10109 @ 06:16:01 page: 1 STABLE Slope Stability Analysis System New User Project : Andrews Datafile: Dynamic Bishop 8 9 1 9 10 1 11 12 2 +++++a++a+#+++aa+a+aa+++aaa++++a++#+a#+a+aa+a#a+++a+a+++++ SOILS SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT. 1 upper CONTINUOUS-BLACK 0.00 36.0 138.000 2 lower CONTINUOUS-BLUE 400.00 40.0 140.000 ++ra+aaa+#aa++t#a+t+++#+a++++at++#+t+#at+rat++t#a+++++ta++ PORE PRESSURE SPECIFICATION SOIL PIEZO RU EXCESS Y/N/P Value Value 1 N 0.000 0.000 2 N 0.000 0.000 PIEZOMETRIC SURFACE POINT POINT PORE PRESSURES POINT PRYSSUM +++aaa++a+++++++++a+++a+aa+++++rat#+a+++#aa+a++++at+#+a+++ SLIP DIRECTION (+/- X) - + #+a+++++++aaa+++#waa+++++aaa++++aa+aa++taa+++++++++++a++++ SLIP-CIRCLES AUTOMATIC Circle Centre Grid Extremities 248.000 a + 31.000 * * 279.000 + a 0.000 X spacing -- no. of cols (max 10)= 10 Y spacing -- no. of rows (max 20)= 20 Grid 1 Circles through point 13 Grid 2 Circles through point 14 Grid 3 Circles through point 15 Grid 4 Circles through point 16 Grid 5 Circles through point 17 Grid 6 Circles through point 18 STABLE®2OO2ARAsaodelesLtd Printed on: 09/10109 @ 06:15:01 Page: 2 1 . 00 1 . 1 0 1 . 20 1 . 30 1 . 40 1 . 50 1 . 60 1 . 70 ....w`1 . 80 1 . 90 2 .00 . 95 Project Andrews Datafile Dynamic Analysis Bishop STABLE.2002 hAZ ASSOCicteS Ltd 1 . 00 1 . 1 0 1 . 20 1 . 30 1 . 40 1 . 50 1 . 60 1 . 70 0 1 . 80 1 . 90 2 . 00 1 . 4 Project Andrews Datafile : Static Analysis Bishop STABLE.2002 MZ Assoclotas Ltd APPENDIX E EROSION CONTROL GEOTEXTILE FABRIC 2'x2' WOOD POST (TYP) IRE FABRIC ANDGEO W WRAP AROUND TRENCH OR EQUIVALENT OR BETTER AND WIRE MESH TO AT LEAST ENTIRE 2 6 FT MAX. O.C. BOTTOM OF TRENCH 0.5 FT BEFORE PLACING GRAVEL 2•x2'x5' WOOD POST OR �- 6 F7 12' DEEP, B' VIDE TRENCH EQUIVALENT OR BETTER EXISTING FILLED WITH 3/4' TO 1 1/2' j GROUND SURFACE WASHED GRAVEL i 2 T � zs F7 12' DEEP, 6' WIDE 1 T DIRECTION OF EXISTING TRENCH FILLED WITH WATER FLOv 12' GROUND SURFACE 3/4' TO 1 1/2' 2.5 FT WASHED GRAVEL 2.5 FT �B• BOTTOM EXTENTS OF sn T FENCE - DETAIL GEOTEXTILE FABRIC N.T.S. SILT FENCE N.T.S. HAY OR STRAW MATTING ENERAL NOTES: 1. STRAW SHALL BE AIR DRIED, AND FREE FROM WEED SEEDS AND COARSE MATERIAL. SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON 2. APPLY AT APPROXIMATELY 75 TO 100 POUNDS PER 1000 SQUARE HESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR FEET OF GROUND. HALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. 3. MINIMUM THICKNESS SHALL BE 2 INCHES. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE 4. HAY OR STRAW IS SUBJECT TO BLOWING. KEEP MOIST OR TIED NSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. DOWN, 3. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN LACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED. PERMANENT EROSION CONTROL NOTES, EMPORARY EROSION CONTROL NOTES; SEEDING FOR RAW SLOPES OR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES, ERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE SWALES, LEVEL SPREADERS AND SEDIMENT BASINS. MMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE, ROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS ACCROS %LONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH OR PERPENDICULAR TO THE SLOPE, EPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF 3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE HE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING APPLIED AT THE RATE OF 120 POUNDS PER ACRE. R OTHER APPROVED TREATMENT. 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO RY SEASON (MAY I THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE FOSTER AND PROTECT THE ROOT STRUCTURE, EMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO 5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30, NLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE ARMORING OF THE SEED BED WILL BE NECESSARY, (e.g., THERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING). Y NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' TABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL RECOMMENDATIONS. AMOUNTS SHOULD BE MINIMIZED, ESPECIALLY REAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ADJACENT TO WATER BODIES AND WETLANDS. HROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, REE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION LAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE. ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE ERFORMED DURING THE FOLLOWING PERIODS, MARCH 1 TO MAY 15, AND AUGUST 15 TO PROPORTIONS PURITY GERMINATIO CTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION NAME BY WEIGHT(%) (%) (%) THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE ❑ SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT REDTOP (AGROSTIS ALBA> 10 92 90 OSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90 LASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN CHEWING FESUE 40 97 80 EPTEMBER 30. (FESTUCA RUBRA COMMUTATA) (JAMESTOWN, BANNER, SHADOW, KOKET> N THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT WHITE DUTCH CLOVER 10 96 90 CTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE (TRIFOLIUM REPENS) WNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION D SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT MULCHING EAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR HE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. 1, MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000 ET SEASON (OCTOBER 1 THRU APRIL 30) -- ON SITES WHERE UNINTERUPTED POUNDS PER ACRE. ONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE 2. MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES EMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED GREATER THAN 2-1 (HORIZONTAL+VERTICAL). ❑ AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN 3. MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN HE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON. ALL RANSPORT OFF-SITE IS OBSERVED. AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1. LL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE OVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC HEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER AVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED. ILT FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., WILL NOT BE VIEWED AS DEQUATE COVER IN AND OF THEMSELVES, IN THE EVENT THAT ANY LAND AREA NOT ING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY TABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON HE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL MMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN PPROPRIATELY PROTECTED OR STABILIZED. ILT FENCE PROJECT/ OWNER/ LOCATION- GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE 'STORMWATER MANAGEMENT MANUAL SINGLE FAMILY RESIDENCE OR THE PUGET SOUND BASIN,' OR APPLICABLE COUNTY STANDARDS . GEOTEXTILE FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO THE LENGTH OF GE❑TECHNICAL REPORT ACH BARRIER TO AVOID USE OF JOINTS. IF JOINTS ARE NECESSARY, FILTER FABRIC SHALL BE SPLICED ANDREWS OGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT PARCEL 32234 50 00049 OTH ENDS TO THE POST. MASON COUNTY, WASHINGTON . STANDARD FILTER FABRIC SHALL BE FASTENED USING 1' STAPLES OR TIE WIRES (HOG RINGS) 2 4 IN PACING. . POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEER RIVEN SECURELY INTO THE GROUND. ENVIROTECH ENGINEERING WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVILENT. THE WIRE MESH MAY BE ELIMINATED IF 74 NE HURD ROAD XTRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED. BELFAIR, WASHINGTON 98528 . A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE OF THE 360-275-9374 OSTS AND UPSLOPE FROM THE SILT FENCE. 7. SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. ER❑SI❑N CONTROL MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Planning Division P O Box 279, Shelton, WA 98584 (360)427-9670 Geotechnical ReportReview Acceptance Letter October 15, 2009 STEVE ANDREWS 17950 50TH AVE SO. SEATAC WA 98188 Case No.: GE02009-00083 Parcel No.: 322345000049 Proiect Description: POLE BARN CONSTRUCTION The Geotechnical Report for STEVE ANDREWS has been received and reviewed by the Planning Department. The report was prepared by Michael Staten dated 10/7/2009. Based on the certification provided by the licensed engineer/geologist, the referenced Geotechnical Report was prepared in general accordance with the requirements in the Mason County Resource Ordinance, Landslide Hazard Areas 17.01.100.E.5. Mason County considers the review valid until such time as scope of project, site conditions, and/or regulations change. Should the scope of work, site conditions, and/or regulations change after the original review, then an addendum from the original author of the report may be required to address these changes. I The report would only be re-reviewed if a permit for development were submitted after these changes occur. Mason County does not certify the quality of the work done in this Geotechnical Report. Please contact me at (360) 427-9670, ext. 365 if you have questions. Sincerel Allan Borden Land Use Planner Mason County Planning Department Comments: 10/15/2009 Page 1 of 1 GE02009-00083 l Mason County Review ChecklisV For a Geotechnical Report f Instructions: This checklist is intended to assist Staff in the review of a Geotechnical Report. The Geotechnic& art is reviewed for completeness with respect to the Resource Ordinance. If an item is found to be not applicable, the Report should explain the basis for the conclusion. The Report is also reviewed for clarity and consistency. If the drawings, discussion, or recommendations are not understandable, they should be clarified. If they do not appear internally consistent or consistent with the application or observations on site, this needs to be corrected or explained. If resolution is not achieved with the author, staff should refer the case to the Planning Manager or Director. Applicant's Name: J�7 �� ermit# " 00-7 Q Parcel # 317- (206Q1 Date(s) of the Document(s)reviewed: (X+e Z 9 2-a'b q eb (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, OK? V Comment: (b) A discussion of specific soil types OK? ✓ Comment: (c) A disc sion of ground water conditions OK?Comment: (d) A disc ssion of the upslope geomorphology OK?Comment: (e) A disc sion of the location of upland waterbodies and wetlands OK?Comment: (f) A discussion of history of landslide activity in the activity in the vicinity, as available in the OK?refere ed maps and records Comment: (2) A site pla which identifies the i orta development and geologic features. OK? / Comment: �L(,/ // (3) Locations 9nd logs of exploratory les or probes. OK? Comment: (4) The area f the proposed development, the boundaries of the hazard, and associated buffers and setback shall be delineated top both sides, and toe)on a geologic map of the site. OK? Comment: (5) A minimum of one cross s 'tion at scale whi adequately depicts the subsurface profile, and which incor orates the details of ro osed grade c ang s. OK? Comment: W (6) A description and results N slop sta-bilify analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic s ty factor is 1.1. and the quasi-sta c analysis coeffients should be a value of 0.15. OK? Comment: (7) (a)Appropr' to restrictions n placement of drainage features OK?Comment: (b) Appropriate restrictions on placement of septic drain fields OK? Comment: (c) Approp ate restrictions on placement of compacted fills and footings OK? Comment: (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other usr BE slopes on the property. ;i E Page 1 of 2 Form Effective Junp.,200� ,?E t lOt4 I OK?Comment: (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other lopes on the prope y OK? Comment: (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method o egetation removal. OK? V Comment: (9) Recommendations for the preparation f detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, landslides and h1jarmful con ruction methods. OK? Comment: (10) An ana ysis both on-site and off-site inipacts of the proposed development. OK? Comment: (11) Specif ations of final development conditions such as, vegetative management, drainage, erosion co trol, and buffer widths. OK?�Comment: (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation OK? Comment: (13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature existing and proposed evel p nton the site. OK? Comment: �4 ��r- C r jL1./GPic S-h�� Are the Documents signed and stamped? Type and#of License: ae� �3C' 5' If not approved, what is the next action/recommendation for further action? a#wldol Reviewed by , on Time spent in review: SECOND REVIEW/UPDATE: Reviewed by , on Time spent in second review: THIRD REVIEW/ UPDATE: Reviewed by on Time spent in third review: Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment Page 2 of 2 Form Effective June 2008 I Mason County Department of Community Development Submittal Checklist For a Geotechnical Report Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not applicable,the report should explain the basis for the conclusion. Applicant/Owner_G4T✓ �myj S Parcel# 32 234- 50 CW4/ Site Address I Z9 3-e2 Z2 /lQrg )&ac� AGs0n Cyvon y (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 5 (b) A discussion of specific soil types Located on page(s) S (c) A discussion of ground water conditions Located on page(s) 6 (d) A discussion of the upslope geomorphology Located on page(s) 3 (e) A discussion of the lotion of upland waterbodies and wetlands Located on page(s) (f) A discussion of history of landslide activity in the activity in the vicinity, as available in the referenced maps and records Located on page(s) /01 1 f (2) A site plan which identifies the imI�orfan evelo ment and geologic features. Located on Map(s) !S4P- flan pp, l (3) Locations and logs of exploratory holes or probes. Located on Map(s) 5,4e- j9luv� (Ap,/} (4) The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated(top, both sides, nd toe)on a-geologic map of the site. Located on Map(s) G A%2(4a,f3 ) (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile,and which incorporates the details f p posed grade phanges. Located on Ma p(s) �r�t �, C, (6) A description and results of slope stability analyses performed for both static and seismic loading conditions.Analysis should examine worst case failures.The analysis should include the Simplified Bishop's Method of Circles.The minimum static safety factor Is 1.5,the minimum seismic safety factor is 1.1.and the quasi-static analysis c oetfients should be a value of 0.15, Located on page(s) /2 , boa, D (7) (a)Appropriate restrictions on placement of drainage features Located on page(s) J (b) Appropriate restrictions on placement of septic drain fields P'1UST gE Located on page(s) SITE ( ) Appropriate restrictions on placement of compacted fills and footings FaM i'�``�1'E�;TI Located on page(s) 7, g ON Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) li f (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) z (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation rem val. Located on page(s)il/ (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, landslides and harmful construction methods. Located on page(s) 111M (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) IS (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) /21, 1-�', /+ (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on pages) &�/� (13) A site map drawn to scale showing the property.boundaries,scale,.north arrow, and the location and nature of existing and prQnosed development on the site. Located on Map(s) ar,_( n4_ _ i, hereby certify under penalty of perjury that 1 am a civil e6ginew Lensed in the State of Washington with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical Report,dated Oc* 7 ?,OQ?_, and entitled (qe k n;c afir Coon Resource S alp Ordinance. u, meets�the dents of the Mason County Ordin Landslide rd Section,is complete and true,that the assessment demonstrates conclusively that the risks po ed by the landslide hazard can be mitigated through the Included geotechnical design recommendations,and that old hazards are mitigated in such a manner as to prevent harm to property and public health and safety.(Signature and Stamp) `X, CLYbE tiG o� S WAS& T9�cs' A vo 0 43045 �P O .O C1ST6R � �SSjONALti��` Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.