Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
GEO2019-00073 for BLD2019-01129 - GEO Geological Review - 7/27/2019
P ab + o°orl3 PLANNING 'JUL 3 12019 j 615 W. Aider Street j Geotechnical Report Kennedy Single Family Residence ft M NE Fern Way, Belfair Parcel No. 12329-22-00080 Mason County, Washington July 27, 2019 Project#19137 Prepared For: William and Michelle Kennedy PO Box 77 Belfair, Washington 98528 Prepared By: Envirotech Engineering PO Box 984 Belfair, Washington 98528 Phone: 360-275-9374 PAL CLYDt ST W ASI I � 4 43045 ssJ\at. 07/27/19 I I MASON COUNTY Submittal Checklist COMMUNITY SERVICES Geotechnical Report ixulNnQ 'eminq I nmmmnngn VMm r nnmumrr nna(V 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 is found not applicable,the report should explain the basis for the conclusion. Note:Unless specifically documented,this report does not provide compliance to the International Residential Code Sections R403.1.7 for foundations on or adjacent to slopes,Section R403.1.8 for expansive soils or section 1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes. Applicant/Owner William and Michelle Kennedy Parcel# 12329-22-00080 Site Address 182 NE Fern Way (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 5-6 (b) A discussion of specific soil types, Located on page(s) 7 (c) A discussion of ground water conditions, Located on page(s) 8 (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 vicinity, as available in the referenced maps and records. Located on page(s) 9 (2) A site plan which identifies the important development and geologic features. Located on Map(s) Site Plan—Appendix A (3) Locations and logs of exploratory holes or probes. Located on Map(s) Site Plan and Soil Logs(Appendix B) (4) The area of the proposed development,the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides,and toe)on a geologic map of the site. Located on Map(s) Site Plan (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details of proposed grade changes. Located on Map(s) Soil Profile(Appendix B) (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 coefficients should be a value of 0.15. Located on page(s) 10 Page 1 of 39 (7) (a) Appropriate restrictions on placement of drainage features, Located on page(s) 17 (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) 18 (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) 13 and 15 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 17 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 16- 17 (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) 17 (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 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 12 (11) Specifications of final development conditions such as,vegetative management,drainage,erosion control,and buffer widths. Located on page(s) 17- 18 (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) 18 (13) A site map drawn to scale showing the property boundaries,scale,north arrow,and the location and nature of existing and proposed development on the site. Located on Map(s) Site Plan I, Michael Staten, 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 PAL CLYDe ST Report,dated July 27, 2019, and entitled Kennedy Single WAS y Y.I\ Family Residence, meets all the requirements of the Mason County Resource Ordinance,Geologically Hazardous Areas Section, is complete and true,that the assessment 10 ,��43045 demonstrates conclusively that the risks posed by the landslide �SS�nNAL�`C'\ hazard can be mitigated through the included geotechnical 7/27/19 design recommendations, and that all hazards are mitigated in Disclaimer:Mason County does not such a manner as to prevent harm to property and public certify the quality of the work done in health and safety. this Geotechnical Report. Page 2 of 2 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............................................................................................................ 3 2.3 SURFACE DRAINAGE.......................................................................................................................... 3 2.3.1 Upslope Water Bodies................................................................................................................ 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.................................................................................................7 3.3.1 Groundwater............................................................................................................................... 8 4.0 ENGINEERING ANALYSES AND CONCLUSIONS......................................................................9 4.1 SLOPE STABILITY...............................................................................................................................9 4.1.1 Slope Stability Analysis.............................................................................................................10 4.2 EROSION............................................................................................................................................10 4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION..............................................................................11 4.3.1 Liquefaction..............................................................................................................................11 4.4 LANDSLIDE,EROSION AND SEISMIC HAZARDS CONCLUSIONS........................................................11 I'I 4.5 LATERAL EARTH PRESSURES...........................................................................................................11 4.6 ON-SITE AND OFF-SITE IMPACTS.....................................................................................................12 5.1 BUILDING FOUNDATION RECOMMENDATIONS.................................................................................13 5.1.1 Bearing Capacity.......................................................................................................................13 5.1.2 Settlement..................................................................................................................................14 5.1.3 Concrete Slabs-on-Grade..........................................................................................................14 5.2 EARTHWORK CONSTRUCTION RECOMMENDATIONS.......................................................................14 5.2.1 Excavation.................................................................................................................................14 5.2.2 Placement and Compaction of Native Soils and Engineered Fill...........................................15 5.2.3 Retaining Wall Backfill.............................................................................................................16 5.2.4 Wet Weather Considerations....................................................................................................16 5.2.5 Building Pads............................................................................................................................16 5.3 BUILDING AND FOOTING SETBACKS.................................................................................................16 5.4 SURFACE AND SUBSURFACE DRAINAGE...........................................................................................17 5.5 VEGETATION BUFFER AND CONSIDERATIONS.................................................................................17 5.6 TEMPORARY AND PERMANENT EROSION CONTROL.......................................................................18 5.7 SEPTIC DRAINFIELDS........................................................................................................................18 5.8 STRUCTURAL MITIGATION...............................................................................................................18 6.0 CLOSURE.............................................................................................................................................19 Appendix A-Site Plan Appendix B -Soil Information Appendix C-Slope Stability Appendix D—Erosion Control Appendix E—Drainage Details i 1.0 INTRODUCTION I Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a planned single family residence located at 182 NE Fern Way,identified as parcel number 12329-22-00080, Mason County,Washington. See the vicinity map on the following page for a general depiction of the site location. An initial geotechnical evaluation of the project was conducted by Envirotech on June 25,2019.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. Based on this site characteristic, 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 li subsurface conditions were assessed. After completion of the field work and applicable project research, Envirotech prepared this geotechnical report which, at a minimum, conforms to the applicable MCRO. 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; supporting documentation with relation to slope stability, erosion, seismic considerations, and lateral earth pressures in the Engineering Analyses and Conclusions Section; and, recommendations for foundation, settlement, earthwork construction, retaining walls, erosion control, drainage, and vegetation in the Engineering Recommendations Section. 1.1 Project Information Information pertaining to the planned development of the project was provided by the proponent of the property. The planned development consists of a 1- or 2-story single family residence to replace the existing residence. 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 of the project; • 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 Envirotech Engineering Geotechnical Report PO Box 984 page 1 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 project; • Collect bulk samples,as applicable,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. N w rNE h'xk�r O g a a , 7Belfair project z300 Nood Canal rot s ,Kxr- an n r a Vicinity Map from Mason County Website Envirotech Engineering Geotechnical Report PO Box 984 page 2 Parcel 12329-22-"80 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 I ' I i I 2.0 SURFACE CONDITIONS Information pertaining to the existing surface conditions for the project was gathered on June 25, 2019 by a representative with Envirotech. During the site visit, the type of geotechnical investigation was assessed,site features were documented that may influence construction,and site features were examined that may be influenced by construction.This Surface Conditions Section provides information on general observations, vegetation, topography, drainage and observed slope/erosion conditions for the project and surrounding areas that may impact the project. 2.1 General Observations Currently,the property has an existing driveway,existing septic,and a mobile home to be replaced. Vegetation on and near the project consists primarily of secondary growth firs and other trees and shrubbery common to this area of the Pacific Northwest. An aerial photo of the project and I immediate vicinity is provided on the following page. I 2.2 Topography I 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 inclinometer. See the Site Plan in Appendix A in this report for an illustration of general topography with respect to the planned development. Critical descending slopes,with grades exceeding 40%appear to be within 300 feet of the planned development. The maximum critical slope is approximately 45%with a vertical relief of about 50 feet. Ascending grades are generally located to the northwest of the planned development.These slopes are relatively minor within 300 feet of the project,with a maximum slope grade of at approximately 25%. 2.2.1 Upslope Geomorphology The upland area of the property and beyond is generally situated on a hillside of glacial origin. 2.3 Surface Drainage Runoff originating upslope of the development is mostly diverted away from the property by accommodating topography. Excessive scour, erosion or other indications of past drainage problems were not observed within the immediate vicinity of the planned development. 2.3.1 Upslope Water Bodies There are no apparent water bodies or wetlands located upslope from the planned development that would significantly influence the project. Envirotech Engineering Geotechnical Report PO Box 984 page 3 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 2.4 Slope and Erosion Observations The slope gradients 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. These slope instability indicators or other 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. ,.a �+. ill�lk �• Y" Aerial Photo from Mason County Website Envirotech Engineering Geotechnical Report PO Box 984 page 4 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the project was primarily gathered on June 25, 2019 by a representative with Envirotech.Applicable 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 B of this report includes pertinent information on subsurface conditions for the project, such as subsoil cross-section(s), test pit log(s), and applicable water well report(s). Water well reports were utilized to estimate ground water levels, and if sufficient, were used in identifying subsoil types. Applicable test pit locations are depicted on the Site Plan 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 septic logs,well logs and nearby cut banks extending to depths of up to 200 feet below the natural ground surface. Information on subsurface conditions also included reviewing geological maps representing the general vicinity of the project. Soil samples were not obtained from this project. Envirotech did not measuredthe relative density of the near-surface in-situ soils since the existing house hinders testing locations. 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, Qg. 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 unconfonmably 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. The "Geologic Map of the Belfair 7.5-minute Quadrangle, Mason, Kitsap and Pierce Counties, Washington"by Michael Polenz, Katelin Alldritt, Nicholas J. Heheman, Isablle Y. Sarikhan, and Robert L.Logan,July 2009,provides the following caption(s)for the project area: Envirotech Engineering Geotechnical Report PO Box 984 page 5 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 Vashon glacial ice-contact deposits—Sand,gravel.lodgment till.and Cox ; floyv till.minor silt and clay beds;tan to gray;vartably sorted:loose to compact.massive to well stratified,locally includes over-steepened beds that n picaily reflect sub-ice flow,but their dip may.along:with small-scale shears.also have developed as collapse features or due to glaciotectomc and tectonic deformation:formed in the presence of meltwater alon¢side ice-generally toward the end of the elactation-and is thus commonly accompanied by stagnant-ice features.such as kettles and less-orderly hummocky topography,eskers(also separately mapped as subunit Qge),and subglacial or subaerial outwash channels Deposits and morphologies that support conceptual association with both ice and meltwater are common in the map area and suggest that where unit Qgic is mapped in the presence of fluted topography,it is commonly oniv a few feet thick and locally could hair been mapped as undifferentiated drift (unit Qgd) Elsewhere:the unit may be over 100 ft thick Event Qgic also includes poorly consolidated till commonly accompanied by underlying, angular sand and noted as"sub-glacially reworked till-'by Laprade(2003) (see Geologic Setting),especially in fluted areas that lack dead-ice features See unit Qgo and Fig 4 for discussion of similarities between units Qgic and Qgo(and its subunits Qgos,Qgof.and Qgol).A discrepancy between this map and the Vaughn quadrangle to the south resulted where Logan and Walsh(2007)mapped undifferentiated Quateinary deposits(unit Qu)because they lacked field exposures and geomorphic signs of the dead-ice deposits that are apparent north of the boundary Dead-ice topography-north of the boundary also reveals a sandy deposit mapped as unit Qgos by Logan and Walsh(2007)to be a facies within unit Qgic.Locally divided into `' ~ Opp tt__ 0. I �_ '00: Coe • .�LLo� • � - "� ocx oo. Q. t `a. 09i Om Cr ac "' r Project ° .. Om A 4 �C\ •: `} f 0m Op OV 091 '- _.... Geological Map Department of Natural Resources Washington State Envirotech Engineering Geotechnical Report PO Box 984 page 6 Parcel 12329-22-OW80 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 I 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 currently composed of native soils with indications of fill.Fill depth could be about 6 feet near the planned building footprint.Within test pit locations,soils within the upper 6 feet of natural ground were generally observed to be poorly graded sand(SP).These deposits 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 within selected test pits 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 B 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 Indianola Loamy Sand,k,with 0% -30% slopes. The soil designations are depicted in the aerial photograph below, and descriptions are provided in Appendix B of this report. Envirotech Engineering Geotechnical Report PO Box 984 page 7 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 N R �tA Ilr Soil Survey from USDA Natural Resources Conservation Service 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.Surface seepage or perched groundwater at shallow depths was not observed on-site, nor indicated on the well reports. Envirotech Engineering Geotechnical Report PO Box 984 page 8 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 4.0 ENGINEERING ANALYSES AND CONCLUSIONS The following section includes slope stability,erosion,seismic considerations,and impacts to both on-site and off-site properties. 4.1 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 with relation to current engineering protocol. 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,repeated surficial slope movements,if not repaired, may present a threat to the structural integrity of the slope. If any slope movement arises,the slope should be inspected by an 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 Resource Map from the Washington State Department of Natural Resources (DNR), the project is not within terrain labeled `highly unstable' relating to soils. DNR labeled portions of this project as medium and high slope instability with relation to slopes. A Resource Map from the DNR Forest Practices Application Review System is provided below: N r— ■ T . . 0 i 11 ; wir r ■■ ti % oil so oils . w FfOject ■■■� Hydric Sods Highly Unstable ■ j■ Highly Erodible ■ •� No Data or Gravel Pits ea Slope Stability-West ■ ■ Moderate Slope Instability =33 00 60ptt ■ J ■ High Slope Instability 1:9.028 i Resource Map from Washington State Department of Natural Resources Website Envirotech Engineering Geotechnical Report PO Box 984 page 9 Parcel 12329-22-OW80 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 4.1.1 Slope Stability 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: Soil unit weight: 100 pcf Angle of internal friction: 33 degrees Cohesion: 0 psf Based on the slope stability analysis, unacceptable factors of safety could be present on and near the critical slope,but 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 at least 1.5 and 1.1, respectively.See the slope stability information in Appendix C for a depiction of minimum factors of safety away from the project. 4.2 Erosion Based on the USCS description of the project soils,the surface soils are considered low erodible. According to the Resource Map from the Washington State DNR,as provided above,the project is not within terrain labeled `highly erodible.' This project is not within an erosion hazard area as defined by the MCRO.Erosion hazard areas are those with USDA SCS designations of River Wash (Ra), Coastal Beaches (Cg), Alderwood Gravelly Sandy Loam on slopes 15% or greater(Ac and Ad), Cloquallum Silt Loam on slopes 15% or greater (Cd), Harstine Gravelly Sandy Loam on slopes 15%or greater(Hb),and Kitsap Silt Loam on slopes 15%or greater(Kc). It is our opinion that minor erosion control recommendations provided in this report is sufficient for the development of this project, and additional engineered erosion control plans are not required. Temporary and permanent erosion control measures are 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. The Temporary and Permanent Erosion Control Section (Section 5.6) of this report consist of specific erosion controls to be implemented. Additional erosion control information and specifications may be found in the latest addition of the "Stormwater Management Manual for Envirotech Engineering Geotechnical Report PO Box 984 page 10 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 Western Washington," prepared by the Washington State Department of Ecology Water Quality Program. 4.3 Seismic Considerations and Liquefaction 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 approximately 6 miles to the south of this project. This information is based on the USGS Quaternary Fault and Fold Database for the United States. Potential landslides due to seismic hazards have been considered, and are addressed in the Slope Stability Analysis Section provided earlier in this report. 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. 4.3.1 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. 4.4 Landslide,Erosion and Seismic Hazards Conclusions DNR indicated historic landslide activity near the project.Mapped slope conditions,as delineated by the Departments of Ecology and/or Natural Resources, were considered in our slope stability assessment. Based on the proximity and severity of mapped delineations with respect to the proposed development,results of the aforesaid slope stability analysis,observed surface conditions, and other pertinent information, it is our opinion that the proposed development may occur in accordance with the recommendations in this geotechnical report. 4.5 Lateral Earth Pressures Retaining walls may be utilized for this project. The 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.A structural or geotechnical professional should design retaining walls based on specific conditions. Envirotech Engineering Geotechnical Report PO Box 984 page 11 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 Soil parameters for the structural design of retaining walls may be estimated as 134 pounds per cubic foot(pcf)and 118 pcf for engineered fill and native soils,respectively.The angle of internal friction may be estimated as 36 degrees and 32 degrees for engineered fill and native soils, respectively. These soil parameters are based on soil type and placement conforming to the Earthwork Construction Recommendations Section in this report. 4.6 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 opinion is based on the expected site development, existing topography, existing nearby development, land cover, and adhering to the recommendations presented in this report. Future development or land disturbing activities on neighboring properties or properties beyond adjacent parcels that are upslope and/or downslope from the subject property could cause problems to the subject property. For this reason, future development or land disturbance near the subject property should be evaluated by a geotechnical engineer. Envirotech Engineering Geotechnical Report PO Box 984 page 12 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 5.0 ENGINEERING RECOMMENDATIONS The following sections present engineering 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; soil/geologic conditions that were identified from the geotechnical investigation that is summarized in the Subsurface Investigation Section;and,project research,analyses and conclusions as determined in the Engineering Analysis and Conclusions Section. Recommendations for the project that is provided herein, includes pertinent information for building foundations, earthwork construction, building and/ or footing setbacks,drainage,vegetation considerations,and erosion control. j5.1 Building Foundation Recommendations I 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. Foundation parameters provided herein account for typical structural pressures due to the planned type of development.A structural analysis is beyond the scope of a geotechnical report, and a structural engineer may be required to design specific foundations and other structural elements based on the soil investigation.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. 5.1.1 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 that is competent and unyielding. 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 continuous footing width of 15 inches shall be placed at a minimum of 12 inches below the existing ground surface atop unyielding soils, and below fill soils if encountered within the foundation footprint. For a columnar load of no more than 3 tons, a circular or square isolated foundation diameter or width shall be at least 24 inches. 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. Envirotech Engineering Geotechnical Report PO Box 984 page 13 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 5.1.2 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 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. 5.1.3 Concrete Slabs-on-Grade Interior slabs, if utilized, should be supported on a minimum of 4 inches of compacted coarse, granular material (Retained on U.S. Sieve #10 or greater) that is placed over undisturbed, competent native subgrade or engineered fill per the Earthwork Recommendations Section below. 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 this report, concrete slabs should also be designed for structural integrity and environmental reliability. This includes vapor barriers or moisture control for mitigating excessive moisture in the building. 5.2 Earthwork Construction Recommendations Founding material for building foundations shall consist of undisturbed native soils to the specified foundation depths.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. 5.2.1 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, not as described in this report, 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. Envirotech Engineering Geotechnical Report PO Box 984 page 14 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 511 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 horizontal foot for each foot of compacted or re-compacted fill depth beneath the foundation. See the illustration below. FOOTING COMPACTED NATIVE SOILS OR ENGINEERED 1 FILL 1 I I-I IT1 III T I ' UNDISTURBED SUBGRADE 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. Because of moisture sensitivity, importing and compacting engineered fill may be more economical than compacting disturbed native soils. Engineered fill shall include having the soils retained on the No. 4 sieve crushed (angular), and 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 Particle Size Distribution of Engineered Fill Compaction shall be achieved in compacted lifts not to exceed 6 inches for both 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 2:1 (horizontal:vertical). Utility trenches or other confined excavations exceeding 4 feet should conform to OSHA safety regulations.Permanent cut and fill slopes shall be limited to a slope of 2:1,unless otherwise approved by an engineer. Envirotech Engineering Geotechnical Report PO Box 984 page 15 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 513 Retaining Wall Backfill Native soils may be used as retaining wall backfill for this project if the total wall height is 4 feet or less and the recommendations below are followed.Native soils for retaining walls exceeding 4 feet in height must be approved by the local authority or evaluated by an engineer. Backfill may consist of engineered fill, as presented in this report, or borrow material approved by a geotechnical engineer. Compaction of these materials shall be achieved in compacted lifts of about 12 inches. Each lift should be uniformly compacted to at least 85%, and no more than 90% of the modified Proctor maximum dry density (ASTM D 1557).If pavement or building loads are planned to be located within retaining wall backfill,then 90%compaction is required.In addition,heavy construction equipment should be at a distance of at least V2 the wall height. Over-compaction and limiting heavy construction equipment should be prevented to minimize the risk of excess lateral earth pressure on the retaining structure. Envirotech recommends that retaining wall backfill is compacted with light equipment such as a hand-held power tamper.If clean,coarse gravel soils are utilized as engineered fill, and surcharges will not influence the retaining wall, compaction may be achieved by reasonably densifying granular soils with construction equipment. 5.2.4 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. 5.2.5 Building Pads Building pads for this project, if utilized, shall be constructed per the fill placement and compaction recommendations as presented above. Both engineered fill and native soils may be used for building pads. Building pad slopes shall be no steeper than 2:1 for both compacted engineered fill and re-compacted native soils used as fill.Building pad fill shall be"keyed"into the existing subgrade to a depth of at least 2 feet below the existing ground surface. The term "keyed," as used here, implies that the interface between the building pad and subgrade is horizontally level.Alternatively,building pads may be keyed into the subgrade to the above specified depth, and stepped. Stepped fill should be keyed into the subgrade at a minimum width of 10 feet. All footings shall be located at least 5 feet away from the top of the engineered fill slope. 5.3 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 25 feet footing Envirotech Engineering Geotechnical Report PO Box 984 page 16 Parcel 12329-22-OW80 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 setback from the face of the nearby descending slopes exceeding 40%. See the figure below and the Site Plan in Appendix A for an illustration of the setbacks. STRUCTURE TOP OF SLOPE SLOPE FACE� _ I IT-- -Tr- - ' �--- SETBACK FOOTING From the illustration above, structures may be located closer to the top of slope by extending the foundation deep enough to maintain the recommended setback. In addition, the required setback may be reduced by mitigation,and subsequently would require additional geotechnical studies. 5.4 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 immediately. 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. Leakage of water pipes, both drainage and supply lines,shall be prevented at all times. If impervious thresholds are exceeded per the prevailing agency code,then engineered stormwater management plans are required for this project. The drainage engineer must coordinate with a geotechnical engineer for input with relation to slope stability prior to submitting drainage plans. If stormwater management plans are not required for this project, then the following recommendations should be followed. For this project,we recommend that infiltration is avoided in order to maintain slope stability, and that roof downspout dispersion on splash blocks are employed.Recommended drainage details are provided in Appendix E of this report. 5.5 Vegetation Buffer and Considerations For this project, we believe that a detailed clearing and grading plan is not warranted unless the prevailing agency thresholds are exceeded, and basic vegetation management practices should be adhered to. Vegetation Buffer-Vegetation shall not be removed from the face of the critical 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 Envirotech Engineering Geotechnical Report PO Box 984 page 17 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 be graded and re-compacted in order to restore the terrain similar to preexisting conditions and drainage patterns. See the Site Plan in Appendix A of this report for a depiction of the vegetation buffer. 5.6 Temporary and Permanent Erosion Control Erosion control during construction should include minimizing the removal of vegetation to the least extent possible.Erosion control measures during construction may include stockpiling cleared vegetation, silt fencing, intercepting swales, berms, straw bales, plastic cover or other standard controls. Although other controls may be used, if adequate, 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 D for sketches and general notes regarding selected erosion control measures. The Site Plan in Appendix A depicts the recommended locations for erosion control facilities to be installed as necessary. Permanent erosion control is 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 D. 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. 5.7 Septic Drainfields Septic drainfields were considered in our geotechnical evaluation.This includes septic drainfields with relation to the observed soil conditions, expected vegetation removal, and existing and proposed topography.Based on the aforesaid parameters,the septic drainfields are not expected to adversely influence critical slopes.This is also based on compliance with all recommendations in this report. 5.8 Structural Mitigation With respect to landslide alleviation or slope improvements, structural mitigation is not necessary for this project. This determination is based on the anticipated improvements of the project, engineering conclusions,and compliance with all recommendations provided in this report. Envirotech Engineering Geotechnical Report PO Box 984 page 18 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 APPENDIX D DRAINAGE DETAILS EHERAL NOTES- PERMANENT EROSION CONTROL NOTES- . SHOULDTHE TEMPORARY EROSIO N AND SEDIMENT CONTROL MEASURES SHOWN ON SEEDING FOR RAW SLOPES HESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR L BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL MALL INSTALL ADDITIONAL EROSION AND SEDIMENT COiTR13L FACILITIES. MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES, .ALL EROSION AND SEDIMENT CONTROU FACILITIES AND DEVICES SHALL BE SWALES, LEVEL SPREADERS AND SEDIMENT BASINS. NSPECTED DAILY AND IMMEDIATELY MAINTAINED,IF NECESSARY. 2.THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE, .ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN FOLLOWING SURFACE ROUGHENING.PERFORM ALL OPERATIONS ACCROS UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED, OR PERPENDICULAR TO THE SLOPE. I SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE NPORARY EROSION CONTROL NOTES. APPLIED AT THE RATE OF 120 POUNDS PER ACRE 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL 13R ALL AREAS WHICH HAVE BEEN STRIPPED [F VEGETATION OR EXPERIENCED LAND REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FIR A FOSTER AND PROTECT THE ROOT STRUCTURE. RIOD EXCEEDING THE LISTED CRITERIA BELOW.ALL DISTURBED AREAS MUST BE 5, SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30, IMMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED ARMORING OF THE SEED BED VILL BE NECESSARY, (e4. ROSION CONTROL TREATMENT APPLICABLE TO THE TIME IF YEAR. GRASS SEEDING GE=XTILES, JUTE MAT,CLEAR PLASTIC COVERING). NINE WILL OILY BE ACCEPTABLE DURING THE MONTHS [F APRIL THROUGH 6,FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' EPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF RECOMMENDATIONS.AMOUNTS SHOULD BE MINIMIZED, ESPECIALLY HE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING ADJACENT TO WATER BODIES AND WETLANDS. HITHER APPROVED TREATMENT. USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION RY SEASON MAY 1 THRU SEPTEMBER 30) — THE CLEARING OF LAND, INCLUDING THE CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE. MOVAL ff EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO Y AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE PROPORTIONS PURITY GERKINATIM THERVISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED NAME BY WEIGHT(YJ (X) (X) Y NO LATER THAN SEPTEMBERR 30(F A GIVEN YEAR. UNLESS IMMEDIATE TABD_IZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL REDTOP(AGROSTIS ALBA) 10 92 90 AS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ANNUAL RYE(III UM MULTff1ORUM) 40 98 90 HRouGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING,EROSION BLANKETS, CHEWING FESLE 40 97 BO REE DRAINING MATERIAL, ETC., BY SEPTEMBERR 30 OR SOONER PER THE APPROVED (FESTUCA RUBRA CONNUTATA) AN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, (JAMESTOWN, BANNER, SHADOW,KOOKET) RTILIZING AND MULCHING [F CLEARED ER OTHERWISE DISTURBED AREAS SHALL BE WHITE DUTCH CLOVER 10 % 90 RFORMED DURING THE FOLLOWING PERIODS-MARCH 1 TO MAY 15,AND AUGUST 15 TO (TRIFOLIUM REPENS) CTOBER L SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION THE PROJECT IS IMPEDIMENT AND THE 04VIRD14ENTAL CONDITIONS ARE CONDUCIVE MULCHING 11 SATISFACTORY GROWTH, IN THE EVENT THAT PERAIENT STABILIZATION IS NOT SSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING,L MATERIALS USED FOR MULCHING ARE RECOMMENDED TD BE WOOD STIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE or WOO PTEMBER 30. POUNDS PER ACRE. 2.MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES N THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT GREATER THAN 2.1 (MORI Z13NTAL-VERT ICAO, CTIVITIES ARE DISCONTINUED F13R AT LEAST 4 CONSECUTIVE DAYS, THE 3.MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN VNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASOK ALL D SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER L .EAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR HE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. TOPSELING AET SEASON (M-MBER 1 THRU APRIL 30)—ON SITES WHERE UHDNTERUPTED L TOPSOIL SHOULD BE USED FOR THIS PROJECT DUE TO HIGHLY STRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE DENSE EXPOSED SOILS. MOVAL OF EXISTING VEGETATION AMC OTHER GROUND COVER, SMALL BE LIMITED 2,TOPSOIL SHOULD BE PLACED ON SLOPES NOT EXCEEDING 2-L 0 AS MUCH LAND AREA AS CAN BE COVERED IR STABILIZED WITHIN 24 HOURS IN 3, STRIPPING AND STOCKPILING ON-SITE SOTS SHALL OILY IE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT PERMITTED F TOPSOIL IS FRIABLE AND LOAMY (LOAM, SANDY LOAN, RANSPORT OFF-SITE IS OBSERVED. SILT LOAM, SANDY CLAY LOAM, CLAY LOAM), LL 4,STRIPPING SHALL BE CONFINED TO THE IMMEDIATE CONSTRUCTON CLEARED OR DISTURBED AREAS STALL RECEIVE APPROPRIATE PROTECTIVE AREAS A FOUR TO SIX INCH STRIPPING DEPTH IS COMMON, BUT OVER OR BE OTHERWISE STABILIZEO, SUCH AS MULCHING, NETTING, PLASTIC DEPTH MAY VARY DEPENDING ON THE PARTICULAR SOIL.ALL HEFTING,EROSION BLANKETS, FREE DRAINING MATERIAL,ETC., WITHIN 5 DAYS AFTER SURFACE RUNOFF C04TRI STRUCTURES SHALL BE IN PLACE BEFORE AVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKER STRIPPING. 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 NG ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT DEEN APPROPRIATELY TABILIZED 5 DAYS AFTER HAVING BEEN CLEARED,ALL CONSTRUCTION ACTIVITY ON HE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL IMMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN PPROPRIATELY PROTECTED IR STABILIZED. STOCKPILE MANAGD04T L STOCKPILE SHALL E STAIRLIZED(WITH PLASTIC COVERING QR OTHER APPROVED DEVICE)DAILY BETWEEN MQVEMBER AND MARCH 3L z IN MY SEASON,SEDIMENT LEACH K FROM STICK PILES MuST BE PREVENTED 3.TOPSOIL SHALL NOT E PLACED WHOLE N A FROZEN OR MUDDY CONDITION,WHEN THE SUDGRADE IS EXCESSIVELY VET,OR VHEN CONDITIONS EXIST THAT MAY OTHERWISE BE DETRIMENTAL TO PREFER GRADING OR PROPOSED SODDM OR SEEDINC. 4.PRLVIOJSLY ESTABLISHED GRADES a THE AREAS TO E TO'SDO ED SHALL E K44NTADED ACCORDINC TO THE APPROVED PLANS. STABILIZED C13NSTRUCTM N ENTRANCE L MATERIAL SHALL BE 4 INCH TO 8 INCH QUARRY SPALLS (4 TO 6 INCH FIR RESIDENTIAL SINGLE FAMILY LOTS) AND MAY BE TOP-DRESSED WITH 1 OUCH TO 3 INCH ROCK. (STATE STANDARD SPECIFICATIONS, SECTION 8-15.) 2.THE ROCK PAD SMALL BE AT LEAST 12 INCHES THICK AND 50 FEET LONG (20 FEET FOR SITES WITH LESS THAN 1 ACRE [F DISTURBED SOIIL>. WIDTH SHALL BE FULL WIDTH OF THE VEHICLE INGRESS AND EGRESS AREA. SMALLER PADS MAY BE APPROVED FOR SINGLE-FAMILY RESIDENTIAL AND SMALL COMMERCIAL SITES 3.ADDITIONAL ROCK SHALL BE ADDED PERIODICALLY TO MAINTAIN PROPER FUNCTION OF THE PAD. 4.IF THE PAD DOES NOT ADEQUATELY REMOVE THE MUD FROM THE VEHICLE WHEELS,THE WHEELS SHALL BE HOSED OFF BEFORE THE VEHICLE ENTERS A PAVED STREET.THE WASHING SHALL BE DOE ON AN AREA COVERED WITH CRUSHED ROCK AND WASH WATER SHALL DRAIN TO A SEDIMENT RETENTION FACILITY OR THROUGH A SILT FENCE [.A T FENCE EUrEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE 'STORMWATER MANAGEMENT MANUAL THE PUGET SOUND BASIN,' OR APPLICABLE COUNTY STANDARDS EOTEXTILE FILTER FABRIC SMALL BE PURCHASED IN A CONTINUOUS R0.L CUT TO THE LENGTH O' H BARRIER TO AVOID USE OF JOINTS.F JOINTS ARE NECESSARY, FILTER FABRIC SMALL BE SPLICED ETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT H ENDS TO THE POST. TANDARD FILTER FABRIC SHALL BE FASTENED USING I' STAPLES OR TIE WIRES (HOG RINGS)2 4 IN CING, OSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET,AND VEN SECURELY INTO THE GROUND. WIRE MESH SWILL BE rX2'X14 GAUGE OR EQUIVLENT, THE WERE MESH MAY BE ELIMMD4ATEO FRA-STRENGTH FILTER FABRIC (MQ6ILAMENT), AND CLOSER POST SPACING IS USED TRENCH SWILL [E EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE I2F THE TS AND UPSL33E FROM THE SILT FENCE 7. SILT FENCES SMALL BE LOCATED DOWNSLOPE FROM THE CLEARING LD4ITS OF THE PROJECT. 6.0 CLOSURE Based on the project information provided by the owner, the proposed development, 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.It is not recommended that a qualified engineer performs a site inspection during earthwork construction unless fill soils will influence the impending foundation.However,if native,undisturbed subsurface conditions found on-site are not as presented in this report,then a geotechnical engineer should be consulted. 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 potentially protect life and/ or property. Semantics such as `suggested' or `optional' refer that the associated design or specification may or may not be performed, but is provided for optimal performance. 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 neighboring properties, changes to ordinances or regulatory codes, or broadening of accepted geotechnical standards may affect the long-term 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 7��K- ;�tr Sz-ztL Jessica Legarza,M.S. Michael Staten,P.E. Staff Geologist Geotechnical Engineer Envirotech Engineering Geotechnical Report PO Box 984 page 19 Parcel 12329-22-00080 Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 July 27,2019 APPENDIX A SITE PLAN SCALE, I INCH 100 FEET 0 0 25 FT !0 FT CONSTRUCTION VEGETATION SETBACK REMOVAL SETBACK PROPERTY LIM 4 EXISTING MOBILE HOME AND CARPORT TO BE 13/ REPLACED \` 4% 5 1•t 3% A V f EXISTING SEPTIC DRAINF]ELD KAPPR TPI© A, V TOP OF CRITICAL. TOE Or CRITIC& SLOPE EXCEEDING 40% SLOPK EXCEEDING 4DX PROJECT/ OWNER/ LOCATION. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE, GENERAL LOCATIONS SINGLE FAMILY RESIDENCE ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE GEOTECHNICAL REPORT GEOTECHNICAL REPORT. 2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. KENNEDY CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE,AND 182 ME FERN WAY INCORPORATED FULD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL LEGEND PARCEL 12329-22-00080 REPORT. MASON COUNTY, WAS I BOUNDARIES WERE NUT PREPARED BY A LICENSED SURVEYOR.LOCATIONS iENPOttARY ENGINEER- OP SITE FEATURES THAT ARE SHOWN HERE, SUCH AS TOP[B' SLOPES, TOE -f ++EROSMN CONTROL ENVVWTECI ENGINEERING [IF SLOOPES, WATER FEATURES, ETC., WITH RELATION TO THE PROPERTY PO BOX 984 LINES MUST BE VERIFIED BY THE OWNER. REC04MENDATMNS IN THE SLOPE INDICATOR BELMR, WASHINGTON 98528 GEOTECHNICAL REPORT PROVIDE SETBACKS, BUFFERS, DEPTHS, ETC.VTTH 360-275-9374 RELATION TO GEOLOGIC FEATURES, NOT PRO ING PROPERTY LINES.THESE GEOLOGIC --80' EXIST CONTOUR FEATURES PROPERTIES. BE LOCATED ON THE SUBJECT PR<pERTY OR NEIGHBORING TP10 TEST PIT SITE PLAN I it APPENDIX B SOIL INFORMATION I i -1—An HDNIDYi.:wc, WALD D"-r E¢T —PROPOSED HOUSE 177 �EXISTING GRADE IN PDORL. GRADED SAND (SP) SECTIO_A_q MaJECT/OV1ER/LOCATION, SINGLE FAMILY RESIDENCE GEOTECHNICAL REPORT KOWDY PARCEL I2729 ee 90090 NT WSGM COUY,WASHWTON NOIED orm U HPOR GRADE CHANGES REQUIRED a ORDER TO ACHIEVE [N ROTE POSITIVE DRAINAGE ENV DiOTCCH CNLDCCRIAL e]THC SOL PROELE IS ACCURATE ECIt THE DEPTH OF 0 bS MA 7 ® TI SERVED TEST PITS AT E SA[C IMl LOCATIO ]60-2Ty.f3r774NS. DELEAIR, TW 7DYD f� LOVER DEPTHS ARE IASED RI SITE 1E�04r, Loud, WELL L ,AND/Ot CkP[RSN('r a THE GENERAL AREA, SOIL PROFILE TEST PIT LOG TEST PIT NUMBER TP-1 PROJECT: Kennedy Geotechnical Report DATE OF LOG: 6'25/2019 PROJECT NO: 19137 LOGGED BY: MCS CLIENT: William and Michelle Kennedy EXCAVATOR: N/A LOCATION: 182 NE Fern Way 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 0 SP Poorly graded SAND 1 _ 2 r. 3 } 4 5 6 Excavation terminated at approximately 6 feet 7 8 9 10 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains onty to this boring and should not be Geotechnical Engineering interpreted as being rn&cihve of the entire site. Map Unit Description Indianola loamy sand,15 to 30 percent slopes—Mason County, Washington Mason County, Washington Ic—Indianola loamy sand. 15 to 30 percent slopes Map Unit Setting National reap unit symbol 21:639 Elevation. 0 to 980 feet IVfean annual precipitation 30 to 81 Inches Mean annual air temperature 48 to 50 degrees F Frost-free period 170 to 210 days Farmland classification Farmland of statewide Importance Map Unit Composition Indianola and similar soils 85 percent Minor components 15 percent Estimates are based on observations,descriptions,and transects of the mapunrt Description of Indianola Setting Landform Eskers,kames.terraces Landform position(two-dimensional) Backslope Landform positron(three-dimensional) Side slope Down-slope shape: Linear Across-slope shape Linear Parent matenal Sandy glacial outwash Typical profile Ot-0 to 1 inches. slightly decomposed plant matenal A- 1 to 6 inches. loamy sand Bwl-6 to 17 inches. loamy sand Bw2- 17 to 27 inches: sand BC-27 to 37 inches. sand C-37 to 60 inches. sand Properties and qualities Slope 15 to 30 percent Depth to restrictive feature More than 80 inches Natural drainage class: Somewhat excessively drained Capacity of the most limiting layer to transmit water(Ksat). High to very high(5 95 to 99,90 in/hr) Depth to water table More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile. Low(about 3.9 inches) Interpretive groups Land capability classification(irrigated). 6e Land capability classification(nonirrigated). 4e Hydrologic Soil Group: A Il» Natural Resources Web Sal Survey 7262019 Conservation Service National Cooperative Sal Survey Page 1 of 2 Map Unit Description Indianola loamy sand,15 to 30 percent slopes--Mason County. Washington Forage suitability group. Droughty Soils(G002XS401 WA), Droughty Soils(G002XN402WA) Hydric soil rating No Minor Components Alderwood Percent of map unit: 8 percent Landform: Ridges,hills Landform position(two-dimensional). Backslope Landform position(three-dimensional) Side slope,nose slope,talf Down-slope shape Linear,convex Across-slope shape Convex Hydnc soil rating No Everett Percent of rnap unit 5 percent Landform. Karnes,eskers,moraines Landform position(two-dimensional) Backslope Landform position(three-dimensional). Side slope Down-slope shape Convex Across-slope shape Convex Hydric soil rating No Norma Percent of map unit 2 percent Landform Depressions,drainageways Landform position(three-dimensional) Dip Down-slope shape. Concave,linear Across-slope shape. Concave Hydric sod rating: Yes Data Source Information Soil Survey Area Mason County,Washington Survey Area Data Version 14,Sep 10,2018 ,I Natural Resources Web Soil Survev 7126t2019 f� Conservation Service National Cooperative Sod Survey Page 2 of 2 II Stan cwd No W 13066 `we ongetr.rle eh D.p.nnwm a Fereltspy Fling y e WATER WELL REPORT UMOuEWELLID•. /f I C 01-01—S Dopy STATE OF WASHINGTON T."Copy-Drlh&'&Copy Wear Right P.nrttt N. a (1) owNER: Jeff Skoubo _ __ b... NE 50 Tima Rd Belfair WA 9852 (2) LOCATK)N OF WELL: C.^ Mason IVId a N1y' tNSaL 29 y 23 f1 11 1W way (20 STREET ADDRESS OF WELL,.., NF 50 Tuna Rd Belfair WA 98528 GJ (3) PROPOSED USE: S Oa- id- _ MumcoW l (10) WELL LOG or ABANDONMENT PIROCEOUNELl DESCfEAT10N VI ❑ Dew w 7es1 W.e _ U!tr f Fahimil o..these.M tsBbr.OW&W.Bed CO.r•r.•r w w IC100.rtl 11"elArNb d 41.0e w er frd w n.1u.d ew m.erw...ut rNeAe een01u14 w*a mm aru e•w to Beth (4) TVPEOFWORK: Oe"'ers'"'mEeroh"Y rArte.of t!n-w0h 1 e atlre ew one)_. aY7gaL FBIOtl 10 = Abandrud I Naw.ee 6 Ilaa+od Duo 1, bed? - -- --- O Deegr W C cade lb Orfsa.1 PACW4eone3 1. B1o1.ry 0 Jane a _qAnA It gravel ----- (S) DIMENSK)NS: Dirtrrrd-am__ 6 bdfw. -- rn ec 55 ter. Depm d�«eras.«_ 15.�_R. Said ----- 15 50 0O (6) CONSTRUCTION DETAN.S: Rhip clay 50 60 c Cm*V Irul.lied __5_ Dam hom���tl 155 ,IL W~ z Dr.m evn --kU i with eater 100 T r,.•.,1.d Dlarn bast ib i r penorallom: ye►❑ No 11 with water _ _4.0 Type Of perlraw w"-, c andNwswstl nMh " ve1 with water 140 155 paAnalltltlbaha It.10 i pa4abwr6m f1 b i t4 _ somm Iis❑ ele v bblalbebeeart.e4aa _-- a�.+ Two 1b4lea. _a am._lBw sba bbb i b i h_ awswP~ yb.C w[E www wd _ .. fyawtpbadbafn is i -- -- .1iwvwo efld: Am M Iba 1be110do l it O Marw usw m sad_ Retnni a n - z Did my Sirre bpr1r11eaw.d.tfr Ma❑ Nai/, _ _...._ N Typ.dw.lr'+ _. _. Da�hdfl►ab . � Shlnoa d•••he9 sba M - 0 m PUMP: "Sh Awwr.Neme -Goulds_ �+ Ty1w. _ sub. ND 374 - Cn O (8) WATER LEVELS: "°"'1eOe•^A0 0 U Sim 0.r-_-1Q0_ _hawaodwr am LL A�. p.wuw if.ar sours w h Dab .- --- w An.ttwn war 7l orrgsM by _ C) rio.Sarw1__ 1b camomme. + 9_ - (Y) WELL TESTS: Draweo.n Iaewtta.e war woo n lowr.o brew Blare I" c W..P..w Nst maw+y.e[-' sea® p yes.q wanly WELL CONSTRUCTOR CEIITFICATION: Ol E yww _--_.._ _9•l'+nn.reh___a.O'r dwim"a w. __be. I C*hSVWTad anWW OMW reWWsibary for C Sfrud ,of" ,Wl.and IS ♦..• - o0rrlp&xe mt h d WaWwrigbn well�fmxmn Standards Mlterlre Used and L • 1M ifedmatgn haprh.0 Ift @ en tfue 10 my best Fro W ledge and DN W rL 4) Recovery tsu(tlm.ut.r.use when flurry w"0"Imr boo fMaraObom.e. NAME Davis Drlllln top tp watw levri AElyb!( f4etd�rl— rme Wrer L-1 T►rr Weser Lffm Tara war Used a, Add-.Ss Belfair WA 98528 ~ (S;gn d', came No 2062 Deb d ar D.wx hash_ 10 p.IJs1YL tewt___iQ_It rw tiq wm�..r b1a Caarww s A•I.st y1mWh.teat wBm aw M i 1er`_ ._ba. 'DAV I SDI1100A Date_. 10�2.4L��. _.t s— Arbsetifpw o.p.n Da Termie wweq wew was a oA cmi ruble mars' yw(✓ No® (USE ADDITIONAL SHEETS IF NECESSARY) ECL OW 1 20(2103)'•r .-IW- q APPENDIX C SLOPE STABILITY do*.[sz8� -V•szsscZEu,� sTsATX-uK Z>TuzauAQ - aTT38,4ca �oaCo.zg eSpauuax tucTTTTb� _ �oe�Co=g h 9 00 ' Z 06 ' T 06 " T O L T 09 ' T 0s T O 6 T 0£ T O Z T 0 T T 00 ' T 1 _ OO 10 1 . 20 1 . 30 1 . 40 1 . 50 1 . 60 1 . 70 1 8 O LI _ 90 _ 00 93 P j e c t w i 1 1 i a m K e n n e d y H r o j®o t Data£i1a static Analysis Analysis Bishop APPENDIX D EROSION CONTROL i GEOTEXTILE FABRIC WRAP AROUND TRENCH TO AT LEAST ENTIRE BOTTOM OF TRENCH BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR 12' DEEP, 8' WIDE TRENCH EQUIVALENT OR BETTER FILLED WITH 3/4' TO 1 1/2' WASHED GRAVEL OR VEGETAT N \i DIRECTION OF zs r. EXISTING WATER FLOW ar GROUND SURFACE zs R a• SILT FENCE — CROSS SECTION N.T.S. 2'x2' WOOD POST CTYP> GEOTEXTILE FABRIC OR EQUIVALENT OR BETTER AND WIRE MESH @ 6 FT MAX. O.C. e rr � 1 a5 rT EXISTING GROUND SURFACE z 12' DEEP, 8' WID)VEG TRENCH FILLED W 'FT 3/4' TO 1 1/2' 1 2.5 Fr WASHED GRAVEL TIBOTTOM EXTENTS GEOTEXTILE FABRIC SILT FENCE — DETAIL N.T.S. PROVIDE FULL WIDTH 3/4 IN TO 1 1/ µ"rr INGRESS/EGRESS CRUSHED GRAVEL PLACED AT 6 IN MINIMUM DEPTH WELL—DRAINED SOILS —0.02 IN/MIN FULL UDCTM R=25 FT MIN ri — AcrrsS RD14D STABILIZED CONSTRUCTION ENTRANCE N.T.S. HOUSE ROOF DOWNSPOUT SERVES UP TO 700 SF OF ROOF 50 FT MIN VEGETATED FLOW PATH DOWNSPOUT EXTENSION ROOF DOWNSPOUT AND SPLASH BLOCK DETAILS N.T.S. GEO ZO -006_�3 Mason County Review Checklist for a Geotechnical Report Instructions: This checklist is intended to assist Staff in the review of a Geotechnical Report. The Geotechnical Report 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: Ke lrq)' Permit#: I>3LU 6011— a 11 Lq Parcel#: I Z 3 Z 9-TZ - a M81 Date(s)of the Document(s) reviewed: - �U�7 2 , lot 1. (a) A discussion of general geologic conditions in the vicinity of the proposed development, OK? '— Comment: (b) A discussion of specific soil types OK? .1 Comment: (c) A discussion of ground water conditions OK? — Comment: (d) A discussion of the upslope geomorphology OK? Comment: (e) A discussion of the location of upland waterbodies and wetlands OK? Comment: (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records OK? Comment: 2. A site plan that identifies the important development and geologic features. OK? Comment: 3. Locations and logs of exploratory holes or probes. OK? Comment: 4. The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides, and toe) on a geologic map of the site. OK? -� Comment: 5. A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details of proposed grade changes. OK? — Comment: 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 coeffie y nts should be a value of 0.15. OK? Comment: 7. (a) Appropriate restrictions on placement of drainage features OK? r Comment: (b) Appropriate restrictions on placement of septic drain fields OK? Comment: (c) Appropriate restrictions on placement of compacted fills and footings. OK? — Comment: Page 1 of 2 Form Effective June 2008 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. OK? Comment: (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. 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 of vegetation removal. OK? — Comment: 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. OK? - =� Comment: 10. An analysis of both on-site and off-site impacts of the proposed development. OK? Comment: 11. Specifications of final development conditions such as, vegetative management, drainage, erosion control, 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 of existing and proposed development on the site. OK? — Comment: Are the Documents signed and stamped? By whom? License#: License type: (` FIRST REVIEW Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by P", on 0 -� 1 Time spent in review: SECOND REVIEW/ UPDATE ❑ Approved ❑ Need more info. Reviewed by on Time spent in second review: THIRD REVIEW/UPDATE ❑ Approved ❑ Need more info. Reviewed by on . Time spent in third review: Disclaimer. Mason County does not certify the quality of the work done in this Geotechnical Report. Page 2 of 2 Form Effective June 2008