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HomeMy WebLinkAboutGEO BLD2009-00424 - GEO General - 4/27/2009 Case Activity Listing 11/21/2017 3:33:15PM Case #: GE02009-00042 Parcel#: 121182290033 Description: GEO REPORT FOR BLDG PERMIT BLD2009-00424 Assigned Done Activity Description Date I Date 2 Date 3 Hold Disp To By Updated Updated By GEOB050 Report Received 5/26/2009 None DONE G I1 M 5/26/2009 G IN1 M GEOA300 Approved 7/2/2009 None DONE G1311\1 GBM 7/2/2009 GBM Geotechnical Report prepared by Envirotech Engineering and dated 4/27/09 GEOB 100 Planning Review 5/26/2009 7/2/2009 None DONE GBM GBM 7/2/2009 GBM Inspected site on 7/2/09.Bank between residence and cove is heavily vegetated with native vegetation. GEOB500 LHA Buffer Reduction Letter 7/14/2009 None DONE GBM GBM 7/14/2009 GBM Landslide Hazard Covenant was recorded within the Auditor's Office.Copy submitted to Planning and placed in property file. Page I of 1 CaseActivity..rpt Din MAY 2 6 2009 MASON COU" PLANKING Geotechnical Report for Payne Single Family Residence 2492 E Grapeview Loop Road Parcel No. 12118 22 90033 Mason County, Washington ��<< __�DD33 April 27, 2009e Project#0927 Prepared For: Ed Payne �Ntti CLYDR P.O. Box 570 �Nv WASI ��9,,, Grapeview, Washington 98546 Prepared By: Envirotech Engineering °��,pFGIST- 74 NE Hurd Road ssi°N^LtiN�' Belfair, Washington 98528 Phone: 360-275-9374 Fax: 360-275-4789 EXECUTIVE SUMMARY Envirotech Engineering is pleased to submit our geotechnical conclusions and recommendations for the planned single family residence to be located at 2492 E Grapeview Loop Road in Mason County,Washington. The referenced property is located along a shoreline with evidence of slow erosion. However,the Washington State Departments of Ecology and Natural Resources, and site conditions indicate relatively stable slopes with relation to landslide activity. The geotechnical investigation included observing shoreline banks of nearly 20 feet in height, and excavating to a depth of about 3 feet below the ground surface to identify competent soils near the planned residence. Additional subsurface investigations included reviewing water well reports geological maps and other soil maps. The following information is an outline of our recommendations with relation to construction for this project. Details of these recommendations are provided throughout the body of the geotechnical report: Bearing Capacity 1500 psf 16-inch footing width 18-inch footing depth Undisturbed or engineered fill bearing strata Concrete Slabs-on-Grade 4 inches coarse,granular base(plus#10 sieve) Retaining Walls none anticipated Engineered Fill See report for gradation Compact to 95%modified Proctor 8-inch compacted lifts Native Soil Fill Compact to 95%modified Proctor 6-inch compacted lifts Setbacks Footing to be at least 20 feet from slope exceeding 40% Vegetation buffer is minimum of 10 feet from top of slope Erosion Control Straw or silt fence, if necessary Vegetate denuded areas Rip rap protection at all drainage outlets Drainage Footing drains if ground water warrants or footing depth at 2 feet Roof drains required, and outlet downslope and away from structure,not in buffers 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 2.2.1 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 CONDITIONS.............................................................................................6 3.3.1 Groundwater......................................................................................................................... 6 3.4 SOILS TESTING.............................................................................................................................6 4.0 ENGINEERING ANALYSES,CONCLUSIONS AND RECOMMENDATIONS.........................8 4.1 BUILDING FOUNDATION RECOMMENDATIONS..............................................................................8 4.L I Bearing Capacity.................................................................................................................. 8 4.1.2 Settlement............................................................................................................................. 8 4.1.3 Concrete Slabs-on-Grade...................................................................................................... 9 4.2 LATERAL EARTH PRESSURES........................................................................................................9 4.3 EARTHWORK CONSTRUCTION RECOMMENDATIONS....................................................................9 4.3.1 Excavation............................................................................................................................ 9 4.3.2 Placement and Compaction of Native Soils and Engineered Fill........................................ 10 4.3.3 Retaining Wall Backfill....................................................................................................... 11 4.3.4 Wet Weather Considerations............................................................................................... 11 4.4 SLOPE STABILITY....................................................................................................................... 11 4.4.1 Slope Stability Assessment and Analysis............................................................................. 13 4.4.2 Building and Footing Setbacks........................................................................................... 14 4.5 EROSION..................................................................................................................................... 14 4.5.1 Temporary Erosion Control................................................................................................ 14 4.5.2 Permanent Erosion Control................................................................................................ 15 4.5.3 Shoreline Recession............................................................................................................ 15 4.6 SURFACE AND SUBSURFACE DRAINAGE...................................................................................... 15 4.6.1 Septic Drainfield Impacts.................................................................................................... 15 4.7 VEGETATION BUFFER AND CONSIDERATIONS............................................................................. 16 4.8 ON-SITE AND OFF-SITE IMPACTS............................................................................................... 16 4.9 SEISMIC CONSIDERATIONS AND LIQUEFACTION......................................................................... 16 4.9.1 Liquefaction........................................................................................................................ 16 5.0 CLOSURE..................................................................................................................................... 18 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 at 2492 E Grapeview Loop Road, identified as parcel number 12118 22 90033, Mason County, Washington (Project). 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, Ed Payne, on April 20, 2009. It was determined that slopes in excess of 40% with a vertical relief of at least 10 feet were present within 300 feet of the planned development. Consequently,the proposed development will require a geotechnical report pursuant to Landslide Hazard Areas of Mason County Resource Ordinance (MCRO) 17.01.100. 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 in order to fulfill the MCRO. 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 is accessed from a gravel surfaced ingress/ egress linking Grapeview Loop Road. The property is currently developed land, including building structures, improved driveway, on- site septic, and other typical residential ancillary features. The planned development consists of a new single family residence. Foundation construction is expected to consist of continuous strip footings with concrete slabs-on-grade or stem walls. Approximate building footprint with relation to site features are illustrated in the Site Map in Appendix A. 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; Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 1 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 • 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 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 Payne Geotechnical Report 74 NE Hurd Road page 2 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 2.0 SURFACE CONDITIONS Information pertaining to the existing surface conditions for the Project was gathered on April 20, 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 Project is currently developed land as previously mentioned. The access road extends near the east property line, and McLane Cove borders the property to the west. Beyond the property, rural residential development exists. Vegetation on and near the Project consists primarily of 2nd or 3`d growth firs,madronas,hemlock,huckleberry, 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. An approximate 20 feet, nearly vertical, shoreline bank is located along McLane Cove. Slope grades of nearly 50%, with a vertical relief of over 30 feet, are located above the aforesaid shoreline bank. 2.2.1 Upslope Geomorphology and Water Bodies Ascending grades are generally located to the east of the planned development. This slope is relatively minor within 300 feet of the Project, with no apparent slope grades of at least 15%. The upland area of the property is situated near a crest. Additional geomorphology that is pertinent to both upslope and downslope areas are provided in the Subsurface Investigation Section of this report. There are no apparent water bodies or wetlands located upslope from the planned development that would significantly influence the Project. 2.3 Surface Drainage Stormwater runoff originating upslope from the anticipated development is expected to be minimal to moderate. Runoff appears to be distributed by sheet flow. Excessive scour, erosion or other indications of past drainage problems were not observed within the immediate vicinity of the planned development. Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 3 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 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. Except for a few leaning trees within the steeper segments of the descending slope, significant mass wasting on the property or within the general vicinity of the Project were not observed or discovered during research. Indications of past landslides, current unstable slopes, deep-seated slope problems,or surficial slope failures were not observed during the site visit. 12 t iC 4ip�. it AIL a i o Soil Survey From USDA Natural Resources Conservation Service Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 4 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 April 27,2009 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the Project was primarily gathered on April 20, 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 test pits extending to depths of up to 2 feet below the existing ground surface, and observing cut slopes/ shoreline banks of up to 12 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. Soil sampling was not performed for this Project. 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 loose to medium dense soils in the upper 36 inches, and very 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, %. 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 glacial till, Qe. Glacial Till is usually described as "unsorted, unstratified, highly compacted mixture of clay, silt, sand, gravel, and boulders deposited by glacial ice of the Puget lobe; gray; may contain interbedded stratified silt, and gravel; sand-size fraction is very angular and contains abundant polycrystalline quartz, which distinguishes this unit from alpine till;cobbles and boulders are commonly striated and(or) faceted; although unweathered almost everywhere, may contain cobbles or small boulders of deeply weathered granitic rock." Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 5 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 3.3 Specific Subsurface Conditions The following subsurface conditions are estimated descriptions of the Project subgrade utilizing 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 possible borrowed fill near the downslope side of the planned home. For engineering purposes, these native soils consist of distinguishable layers, as presented below. The possible fill is apparently a result from past grading activities utilizing soil originating from the property. It appears that the fill depth is less than 2 feet, and recedes towards the proposed home. Soils within the upper 15 feet of natural ground were observed to be moist, light brown to grey silty sand with gravel (SM). Pockets of silty clay (ML-CL) and some cobbles were observed. Hardpan was encountered at a depth of 3 feet below the ground surface near the building pad, and about 1 foot near the top of the shoreline bank. Soils below the upper 15 feet layer to a depth of 20 feet below the ground surface were observed to be mostly grey, low moisture, silty gravel with sand (GM). These soils were very dense with strong cementation. The hardpan may extend to depths greater than 50 feet. This is based on nearby well reports, site geology, and/or knowledge of the general area. 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 Sinclair Shotty Loam, Sp, with 15% - 30% slopes, and Alderwood gravelly sandy loam, Sp, with 5% - 15% 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 80 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 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). Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 6 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 April 27,2009 The general results from the visual classification are presented above in the Subsurface Conditions Section. Specifically, soils within the upper 3 feet in one testing location consisted of approximately 15% gravel, 70% sand-sized soils, and 15% silt with low to medium 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. Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 7 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 April 27,2009 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- or two-story, single family residential structure. 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. Stepped foundations are acceptable, if warranted for this Project. Continuous, isolated, or stepped foundations shall be horizontally level between the bottom of the foundation and the top of the bearing strata. 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 shallow, continuous or 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 width of 16 inches shall be placed at a minimum of 18 inches below the existing ground surface. This depth is expected to extend beyond the small layer of fill, if any. 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 Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 8 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 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 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. 4.1.3 Concrete Slabs-on-Grade Interior slabs, if utilized, should be supported on a minimum of 4 inches of compacted coarse, granular material (Passing U.S. Sieve #10 or greater) that is placed over undisturbed native subgrade or engineered fill. Native soils found at the Project site may be suitable for use as material directly beneath concrete slabs if it meets the aforesaid requirements or screened to meet these requirements. The top 2 to 4 inches of native soil should be removed prior to the placement and compaction of the aforementioned 4-inch coarse,granular material. The recommendations for interior concrete slabs-on-grade as presented herein are only relevant for the geotechnical application of this Project. Although beyond the scope of geotechnical engineering, concrete slabs should also be designed for structural integrity and environmental reliability. This may include some type of vapor barrier or moisture control for mitigating excessive moisture in the building. 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 Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 9 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax: 360-2754789 April 27,2009 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. 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. FOOTING COMPACTED NATIVE SOILS OR ENGINEEREDFILL I I UNDISTURBED SUHGRA)lE 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 6 inches and 8 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 Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 10 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 April 27,2009 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 2:1 (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 Due to the types of subsurface soils, additional provisions may be required during prolonged wet weather. Every precaution should be made in order to prevent free moisture from saturating the soils within excavations. If the bottom of excavations used for footing placement changes from a moist and dense/hard characteristic as presented in this report to muck or soft, saturated conditions, then these soils become unsuitable for foundation bearing material. If this situation occurs, a geotechnical engineer should be notified, and these soils should be completely removed and replaced with compacted engineered fill or suitable native material as presented in this section. 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 `Intermediate' regarding potential landslide activity. Stable slopes are generally not prone to landslides due to small grades and accommodating geology. Historically, intermediate terrains have no known landslides. However, this site is considered Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 11 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 inherently hazardous due the existing geology and/ or topography, and additional 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: 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 not within terrain labeled `highly unstable' or `highly erodible' relating to soils. In addition, DNR did not indicated previous landslide activity near the Project. DNR labeled portions of this project as medium and high slope instability with relation to slopes. This delineation is primarily dependent upon slopes and convergence. Secondly, lithology and precipitation are modeled within this delineation. In summary, this designation is based on mapping without field observations or knowledge of the specific site geology or soils. A Resource Map from the DNR Forest Practices Application Review System is provided below: Project Resource Map from Washington State Department of Natural Resources Website Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 12 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 April 27,2009 4.4.1 Slope Stability Assessment and Analysis Based on site geology, a non-circular slope stability analysis should be performed. However, the Simplified Bishop Method, as presented herein, was utilized in order to comply with the MCRO. Although the method of circles could be an inappropriate tool, it is almost invariable much more conservative in these situations than other conforming slope stability models. In addition, the geotechnical analysis utilized the subsurface angle of repose. 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: Top 1 to 5 feet of weathered soils • Soil unit weight: 124 pcf • Angle of internal friction: 33 degrees • Cohesion: 50 psf Soils below 5 feet • 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 1.7 relative to static slope failures, and 1.2 with relation to seismic conditions. For this Project,at the location of the proposed development, minimum factor of safeties for static and dynamic conditions were estimated to be over 2.0 and 1.5, respectively. See the slope stability information in Appendix D for a depiction of input parameters and example of outputs. Slopes with grades steeper than the angle of repose are confined to the approximate 20- foot bluff. The Departments of Ecology and Natural Resources did not delineate problematic slope instability. Based on this information with respect to the proposed development, results of the aforesaid slope stability analysis, and an evaluation of the shoreline recession rate, it is our opinion that the proposed development should occur in accordance with this geotechnical report. Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 13 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 April 27,2009 4.4.2 Building and Footing Setbacks Provided that assumptions relating to construction occur and recommendations are followed as presented in this report,the factor of safety for slope stability is sufficient for a 20 feet footing setback from the face of the nearby descending slopes exceeding 40%. The building location was presumably staked out, as observed during the site visit. This building envelope location is acceptable with relation to the geotechnical report. See the figure below and the Geologic Map in Appendix B for an illustration of the setbacks. STRUCTURE TOP ❑F SLOPE SLOPE FACE ' I I-I I �• -I I ��-- 20 FT MIN —_� -- FOOTING The required setbacks may be reduced, if necessary. The setback may be decreased by extending the foundation an additional 3 feet in depth below the ground surface. However, the footing setback should be maintained at a minimum of 10 feet from the top of the top of the slope with grades exceeding 40%. 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 Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 14 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 than expected, or erosion control measures are not functioning as needed, additional measures must be implemented immediately. See Appendix E for sketches and general 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. 4.5.3 Shoreline Recession Due to the close proximity of a shoreline, an evaluation of the shoreline recession rate for this Project was completed. This was accomplished by carefully reviewing and comparing aerial photographs of the Project from several sources. Some of these sources include a 1951 aerial for the Soil Survey of Mason County, 2006 aerial from the Washington State Department of Ecology, and various shoreline photographs from the Washington State Department of Natural Resources. Based on available information, we conclude that the past shoreline recession for this Project is less than 10 feet in 50 years. 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, footing drains are optional for the single family residence. If footings are established at depths greater than 2 feet below final grade, then perimeter footing drains are recommended. Roof drains are recommended for this Project,and should be directed to splash blocks or permanent stormwater facilities at least 5 feet downslope from any structure. Stormwater should not be allowed within the 10 feet vegetated buffer. Alternatively, runoff may be tightlined beyond the slopes with grades exceeding 40%with appropriate outfall protection. 4.6.1 Septic Drainfield Impacts The approximate location of the existing septic drainfield is presented on the Site Plan in Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 15 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington April 27,2009 Fax: 360-275-4789 Appendix A of this report. Based on the septic drainfield location with relation to the proposed addition, the drainfields are not expected to adversely influence the structure or critical slopes. 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/ fiction 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 or within a distance of 10 feet beyond the top of the 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. Any disturbed soil shall be graded and re-compacted in order to restore the terrain similar to preexisting 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. Soils below a depth of 3 feet from the existing ground surface may be considered Type C. 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 is over 4 miles to the south 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. Envirotcch Engineering Payne Geotechnical Report 74 NE Hurd Road page 16 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 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 Payne Geotechnical Report 74 NE Hurd Road page 17 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 April 27,2009 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 J /m1' Michael Staten, P.E. Geotechnical Engineer Envirotech Engineering Payne Geotechnical Report 74 NE Hurd Road page 18 2492 E Grapeview Loop Road Belfair,Washington 98528 Parcel 12118 22 90033 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 April 27,2009 APPENDIX A SITE PLAN SCALE, 1 INCH = 40 FEET amm APPRX WELL 0 5 10 20 40 LOCATION EXISTING DRAINFIELD AREA r� McLANE COVE Q EXISTING DRIVEWAY (APPRX) TP ER❑SION CONTROL w APPPTRXR HIG IF NECESSARY + Q ELEVATION CD TPl APPRX, L❑CATI❑N co 9 OF EXISTING —� STRUCTURE —� APPRX, L❑CATION OF PROPOSED HOUSE APPRX, TOP OF SLO E EXCEEDING 40% PROPERTY LINE � 330FT± PROJECT/ OWNER/ LOCATION, O o I'D SINGLE FAMILY RESIDENCE NOTES GE❑TECHNICAL REPORT a 1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. GENERAL LOCATIONS ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE ED PAYNE GEOTECHNICAL REPORT. PARCEL 12118 22 90033 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 LINES 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 TPI@ TEST PIT SITE PLAN PROPERTY LINES. APPENDIX B GEOLOGIC MAP APPRX. TOE OF SLOP SCALE, 1 INCH = 40 FEET EXCEEDING 407 APPRX WELL 0 5 10 20 40 L❑CATI❑N 20 FT BANK u (NEARLY LOFT VEGETATION BUFFER FROM EXISTING DRAINFIELD VERTICAL) TOP OF 40%+ SLOPE AREA I I (SEE GEOTECHNICAL REPORT) q McLANE COVE Q � � EXISTING DRIVEWAY (APPRX) � TP w APPRX. HIG 50%+ +1 u WATER L- ELEVATI❑N CD P T 1 APPRX, L❑CATION 9 OF EXISTING STRUCTURE r----� APPRX, L❑CATI❑N OF PROPOSED HOUSE APPRX, OF SLO E 20FT BUILDING SETBACK FROM EXCEEDING NG 40% TOP OF 40%+ SLOPE (SEE GEOTECHNICAL REPORT) PROPERTY LINE 330FT± / SO LSl LOOSE TO MEDIUM DENSE SILTY SAND o �SIUTY WI HGRAVEL (SM) OVERLYING VERY DENSE PROJECT/ ❑vNERi LOCATION SINGLE FAMILY RESIDENCE SAND AND GRAVEL (SM, GM) GEOTECHNICAL REPORT O NOTES �1 1. ALTERNATIVES FOR REDUCING BUILDING SETBACKS OR VEGETATION ED PAYNE BUFFERS MAY BE PROVIDED IN THE GEOTECHNICAL REPORT. PARCEL 12118 22 90033 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 BELFAIR, WASHINGTON 98528 FEATURES, ETC.,, WITH RELATION TO THE PROPERTY LINES MUST BE VERIFIED BY THE OWNER, RECOMMENDATIONS IN THIS REPORT PROVIDE 80 EXISTING CONTOUR 360-275-9374 SETBACKS, DEPTHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT TPJj@ TEST PIT GE❑L❑GIC MAP PROPERTY LINES. APPENDIX C SOIL INFORMATION VERTICAL AND HORIZONTAL SCALE- I INCH = 40 FEET 1 40 PROPOSED HOUSE LOOSE TO MEDIUM DENSE SILTY SAND WITH GRAVEL (SM) EXISTING GRADE SH❑RELINE BANK APPRX HIGH VERY DENSE GLACIAL TILL WATER (GM, SM) SECTION AzA PROJECT/ OWNER/ LOCATION, SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT ED PAYNE PARCEL 12118 22 90033 MASON COUNTY, WASHINGTON NOTES ENGINEER 1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENV IROTECH ENGINEERING POSITIVE DRAINAGE 74 NE HURD ROAD 2) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF BELFAIR, WASHINGTON 98528 THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS. 360-275-9374 LOWER DEPTHS ARE BASED ON SITE GEOLOGY, WELL LOG(S), AND/OR EXPERIENCE IN THE GENERAL AREA. S❑IL PROFILE TEST PIT LOG TEST PIT NUMBER TP-1 PROJECT: SFR Geotechnical Report DATE OF LOG: 4/20/2009 PROJECT NO: 0927 LOGGED BY: MCS CLIENT: Ed Payne EXCAVATOR: N/A LOCATION: Parcel 12118 22 90033 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, moist, loose to medium dense SILTY SAND with GRAVEL. Gravel is primarily well-graded and 1 subangular. Sand is mostly medium. Low to medium plasticity. 2 3 Very dense'hardpan' Excavation terminated at approximately 3.0 feet 4 5 6 7 8 9 110 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. TEST PIT LOG TEST PIT NUMBER TP-2 PROJECT: SFR Geotechnical Report DATE OF LOG: 4/20/2009 PROJECT NO: 0927 LOGGED BY: MCS CLIENT: Ed Payne EXCAVATOR: N/A LOCATION: Parcel 12118 22 90033 DRILL RIG: None Mason County, Washington ELEVATION: N/A INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A SOIL STRATA, STANDARD PENETRATION TEST DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE AND TEST DATA DEPTH N 10 30 50 SM Loose, brown, moist, SILTY SAND wtih GRAVEL. Sand is mostly medium. Low to medium plasticity. Very dense, grey and light brown 2 x' 4 5 6 7 8 9 10 No Groundwater Encountered ENVIROTECH ENGINEERING This intoimation pertains only to this boring and should not be Geotechnical Engineering interpreted as being indicitive of the entire site. TEST PIT LOG TEST PIT NUMBER TP-2 con't PROJECT: SFR Geotechnical Report DATE OF LOG: 4/20/2009 PROJECT NO: 0927 LOGGED BY: MCS CLIENT: Ed Payne EXCAVATOR: N/A LOCATION: Parcel 12118 22 90033 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 10 11 12 13 14 15 GM Grey and brown, low moisture, very dense SILTY GRAVEL with SAND. 16 Gravel is mostly coarse and subrounded. Sand is mostly well-graded. Non to low plasticity. 17 C Very strong cementation 18 19 20 Bank terminated at approximately 20 feet 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. 411 RE CURRENT WATER WELL REPORT Intent No. it QI Notice or I W237D42 3 . . .. Oh[inal 1"rnPy-Ecology,r cary-owner.J~copy-driller i 7 20 H ColigtructioD/DecanlnissioD("x"in circle) Unique Ecology Well ID Tag No. ALG2t s Q6' ElConstruction Water Right Permit No.EXEMPT WELL ash. Decommission ORIGINAL INSTALLATION Notice $ state C ❑ n of Intent Number �o1�Y Owner Name EDWIN de SHARON PAYN �UIIt of�Co10 Q 1°12�0� Well Street Address 2492 E.GRAPEVIEW LOOP ROAD logy C PROPOSED USE: 63Dornestic ❑ ►ndosmal ❑ Mumcipa City GRAPEVIEW County MASON 0 ❑Dewata ❑Irrigation ❑Test Well o O&cr Location 1/4-1/41/4 Sec 18 T21r R IWM ❑.. — CA TYPE OF WORK: Owner's number of wall(if mora than one) W WM ©one E 0 New well ❑Reconditioned Afs":®Dug ❑Bored ❑Driven LaULon8(s Lat Min/Sec ❑DeepenedDeepenedcable ❑Rotary ❑Jetted ,t,r Lat Dog DIMr,NS1ONSs Disrneaerofwell 6 inches,drilled 92 ft. Still REQUIRED) Long Deg Long Min/Sec C Depth of aonrpliud well 92 fl. 40 CONSTRUC ION DUAIIS Tax Parcel No. 121182290033 Cnsing PEV.=Wled 6 " Diem.fran+1.5 ft to 87 fl. imtow " Dino.flu" It.to ft CONSTRUCTION OR DECOMMISSION PROCEDURE 1V Threaded " Oiam.from R.to ft. Perforations: Yes No Formation:Durnbe by color.ehatacter,size of material and structure,and the lard and nature ofthe material in each stratum penetrated,with at least one entry for each change of Type ofpaforatornud ntwrn�nn. USF,ADDITIONAL SHEETS IF NECESSARY. CSizE of pwb in.by in.and no.of perfa_fiotn_R a_fL MATERIAL FROM TO Screens: 0 Yes ❑No m K-Poe Location 85 BROWN CLAY 0 5 Manufacturer's Name JOHNSON BROWN SILT BOUND SAND,AND GRAVEL, 5 A Type SLOTTED Model No. CEMENTED 63 Diem.5 Slot der.016 fiom 87 ft.to 92 ft. Dion Slot size flan It a ft. GRAY SILT BOUND MEDIUM TO COARSE 63 Cravd/F1Yer paehed Yes ONo Size of grnvollsand SAND 183 Materials placed from @ to R BROWN SILT BOUND SAND AND GRAVEL 83 87 C Ssratx l:f Sea mYes ❑No To what depth?27 ft. SAND,GRAVEL AND WATER 87 92 Material itad in seal BENTONITE CHIPS Did any seats contain unumble water? ❑Yes ®No Type of wsw Depth of gross Mathod of sealing strata off PIMP:Manelhaturer's Name O Type: H.P. z WATER LEVELS: Larnd-grfaoc elevation above mean sa level ft. Static level 44 fL below top of weg Date 2127106 Artesiae pressure lbs.per square inch Due Artesian water is controlled by valm etr:. WELL TES & Drawdown is amount wider level is lowered below static Level Was a pump tat made?❑Yes ®No If ya,by wham 8 Yield aalJmin with ft.dri wdowm after hrs. Yield: ad./mia.with ft.&*vdown after Its. Yield: gal,/min.with A.drawdown slier hrs. W Recovery data(nave aken=zero when pump nursed offl(water level measured from well tO top to water level) Time Water Level Time Weer Level Time Water Level 4W Dare of tat Bailer taat1Q galJmim.with 14 fl,dawdown after 4 Ira. Airtest galinun.with atom sou ft.fbr hra. Artesian flow R.pzn Dab Teayetat re ofwater Was a chemical analysis made? ❑Ya ON- ! Start Date 2/21/06 Completed Date 2/27/06 WELL CONSTRUCTION CERTIFICATION: I constructed and/or accept responsibility for construction of this well,and its compliance with all Washington well construction standards. Materials used and the information reported above are true to my best knowledge and belief. O Driller 0 Engineer 137ralnm N,eme(Ptjgt)MA K Ue.EWN Drilling ConVsay ARCADIA DRILLING INC. Drillaffingimearrvainee Signanre�� I - ..l a i7 Address PO BOX 1790 Drilleror trainee License No. 1992 City,State,Zip SHELTON WA 93584 If TRAINEE, Contractor's Drt&r's Lkeesed No. Registration No. ARCADLM098K1 Due 2128/06 DnJkr's Signature ECY 030-1-20(Rev 3/05) Ecology is an Equal Opportunity Employer. APPENDIX D SLOPE STABILITY STABLE Slope Stability Analysis System New User Project : Ed Payne Datafile: Dynamic Bishop STABLE Version 9.03.00u Bishop aaaaaaaiiaa+#iaa**iiii+t+++#ta+aaiat*aaiwt++airi**iiaii+i+ Ti'TLE Dynamic UNITS (Metric/Imperial) I GEOMETRY DEFINITION POINTS NO. X Y 1 54.000 18.000 2 55.000 22.000 3 123.000 55.000 4 173.000 61.000 5 0.000 0.000 6 50.000 2.000 7 123.000 52.000 8 173.000 56.000 9 17.300 0.690 10 24.580 0.980 11 31.870 1.270 12 39.150 1.570 13 46.440 1.860 14 53.720 16.880 15 61.010 24.910 16 68.290 28.450 17 75.570 31.980 18 82.860 35.520 19 90.140 39.050 20 97.430 42.590 21 104.710 46.120 22 111.990 49.660 23 119.280 53.190 24 126.560 55.430 25 133.850 56.300 26 141.130 57.180 27 148.420 58.050 28 155.700 58.920 LINES Lo X Hi X SOIL 1 2 1 2 3 1 3 4 1 5 6 2 6 1 2 1 7 2 7 8 2 SOILS STABLE02002 MZ Associates Ltd Printed on: 22MM a 14:45:47 Page: � STABLE Slope Stability Analysis System New User Project : Ed Payne Datafile: Dynamic Bishop SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT. 1 Soil-1 CONTINUOUS-BLACK 50.00 33.0 124.000 2 Soil-2 CONTINUOUS-BLUE 400.00 40.0 140.000 YORE YMSSURE 6FECIFICAXION 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 PRESSURE aiwaawi#aaaaaawaaa*ai++#w*aaaawa#aa+iiaai###aa++iaai#w#aaa SLIP DIRECTION (+/- X) - - iaa+#i+a+a++a##+iaaaa++aaa#iaaa+##aaa++a+###iwaaaaa+aaaw+w SLIP-CIRCLES AUTOMATIC Circle Centre Grid Extremities 199.400 a 17.300 * + 155.700 # i 61.000 X spacing -- no. of cols (max 10)- 10 Y spacing -- no. of rows (max 20)- 20 Grid 1 Circles through point 9 Grid 2 Circles through point 10 Grid 3 Circles through point 11 Grid 4 Circles through point 12 Grid 5 Circles through point 13 Grid 6 Circles through point 14 Grid 7 Circles through point 15 Grid 8 Circles through point 16 Grid 9 Circles through point 17 Grid 10 Circles through point 18 Grid 11 Circles through point 19 Grid 12 Circles through point 20 Grid 13 Circles through point 21 STABLES2002 MZ Associates Ltd Printed on: 22/04/09 @ 14:45:47 Page: 2 1 . 00 1 . 1 0 1 . 20 1 . 30 1 . 40 1 . 50 1 . 60 1 . 70 1 . 80 1 . 90 2 . 00 1 . 702 Project : Ed Payne Datafile Static Analysis Bishop STABLE.2002 MZ Aos0ciotes Ltd 00000000000 0 - Nr� � �nc0 � � rn0 - N c 0 � a 0 0� Os C .V o WPM0 N N U = V)"0 � >,N 041 L C a � QIVV, APPENDIX E EROSION CONTROL GEOTEXTILE FABRIC 2'x2' WOOD POST (TYP) GEOTEXTILE FABRIC WRAP AROUND TRENCH OR EQUIVALENT OR BETTER AND WIRE MESH TO AT LEAST ENTIRE Q 6 FT MAX. O.C. BOTTOM OF TRENCH oS FT BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR `-� 6 FT 12' DEEP, B' WIDE TRENCH EQUIVALENT OR BETTER EXISTING FILLED WITH 3/4' TO 1 1/2) � GROUND SURFACE 2 T WASHED GRAVEL 25 FT 12' DEEP, 8' WIDE DIRECTION OF--� EXISTING TRENCH FILLED WITH 1 T WATER FLOW 12- GROUND SURFACE 3/4' TO 1 1/2' 25 FT T2.5 FT WASHED GRAVEL �B BOTTOM EXTENTS OF GEOTEXTILE FABRIC SILT FENCE - DETAIL SIL N.T.S. 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 I-ESE 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. 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, RIOD 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 ONE 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. OTHER APPROVED TREATMENT. 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO Y SEASON (MAY 1 THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE FOSTER AND PROTECT THE ROOT STRUCTURE. MOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO 5. SEED BEDS PLANTED BETWEEN NOVEMBER I AND APRIL 30, Y 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 AS 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 AN 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 RFORMED DURING THE FOLLOWING PERIODS- MARCH 1 TO MAY 15, AND AUGUST 15 TO PROPORTIONS PURITY GERMINATIO TOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION NAME BY WEIGHT(%) (X) (7) 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 ASTIC 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 TIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE (TRIFOLIUM REPENS) NER/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 MOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED GREATER THAN 2-1 (HORIZONTAL,VERTICAL). 0 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. L 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 VING 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 ROPRIATELY PROTECTED OR STABILIZED. ILT FENCE PROJECT/ OWNER/ LOCATIOV, 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 ED PAYNE OGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT PARCEL 12118 22 90033 OTH ENDS TO THE POST. MASON COUNTY, WASHINGTON . STANDARD FILTER FABRIC SHALL BE FASTENED USING V 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. SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. EROSION CONTROL 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. Appiicant/Owner Grp( PG y Parcel# /Z/I8 22. 90033 Site Address Z-,H� O'e L✓_ po1O ;e&V — (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) 6 (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 location of upland waterbodies and wetlands Located on page(s) 3 (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) // (2) A site plan which identifies the i porfa t devveloo ment and geologic features. Located on Map(s) (3) Locations and logs of explorator f holes r robes Located on Maps) 5�` lc i (4) The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be dellneate (top, both sides, and on a geologic map of the site. Located on Map(s) t3 (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the detall$of ro e de changes. Located on Map(s) ;/ ) (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 coeffients should be a value of 0.15. Located on page(s) (7) (a)Appropriate restrictions on placement of drainage features Located on page(s) /S (b) Appropriate restrictions on placement of septic drain fields Located on page(s) /5 (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) � /Q Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. I (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the propert . Located on page(s)_ 17 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) /!!� (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 removal. Located on page(s) /k (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) /¢ . (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 01) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) /¢f (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) (13) A site map drawn to scale showing the property.boundaries, scale, north arrow, and the location and nature of existin a d pr posed development on the site. Located on Ma s hereby certify under penalty of perjury that I am a civil engineer licensed 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 4'Z7-09 ,and entitled&_"7LOcAn;r_,* gcf -�)r Pot Y► e, G;nglt, / aMDIY­Ae;t1,h C e_ meets all the requirements of the Mason Courlity Resource rdlnance, Landslide Hazard Section, is complete and true, that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the Included geotechnical design recommendations, and that all hazards are mitigated in such a manner as to prevent harm to property and public health and safety, (Signature and Stamp) CLYb£S WASr�j�CT'9j�� _43045� ,o crsT�R �sS�CNALti�G`� Page 2 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) /�' (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) /j (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 removal. Located on page(s) /k (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) /4 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s)_ lh� (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) /t /S, /c (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) (13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of existin a d p�rj posed development on the site. Located on Map(s) r 1,�� G/1G�I � � �'� hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geo log ical 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 +-Z7-O9 , and entitled&eo_"e3tI or cx yne' meets all the requirements of the Mason Courity Resource rdinance, Landslide Hazard Section, is complete and true, that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geotechnical design recommendations, and that all hazards are mitigated in such a manner as to prevent harm to property and public health and safety. (Signature and Stamp) tiL CLYD�S 011 FcrsrER� z`v �SSjCNAL, Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.