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Home My WebLink AboutGEO2009-00079 BLD2009-00543 - BLD Engineering / Geo-tech Reports - 9/8/2009 C� Geotechnical Report for Nicholas Johnson Single Family Residence 4671 E State Route 302, Victor Parcel No. 12228 50 02002 Mason County, Washington September 8, 2009 Project#0970 Prepared For: Nick Johnson L CLYpE 4671 E State Route 302 `L•Z`P�o4 WAS y�DTI Belfair, Washington 98528 Prepared By: 916109 Envirotech Engineering �o�� Fc s°�R�o 74 NE Hurd Road sS�UNALNG Belfair, Washington 98528 Phone: 360-275-9374 Fax: 360-275-4789 OK? Comment: (e) Recommended setback fr m the landslide hazard areas shoreline bluffs and the tops of other lopes on the prope OK? V Comment: (8) Recommendations for the prepa ation 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 egetation removal. OK? Comment: (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies t specific mitigating measures to be implemented during construction to protect the slope f o erosion, landslides and harmful construction methods. OK? Comment: (10) An analys' of both on-site and off-site impacts of the proposed development. OK? V Comment: (11) Specifications of final development conditions such as, vegetative management, drainage, erosion c�tttrol, and buffer widt OK? t/ Comment: l �� (12) Recommend tions for the prebaration 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 natur of existing and propos d d velopgrAnt on the site. OK? Comment: 1 / IV Are the Documents signed and sssttampe/d�? rim Type and #of License: (� "l oy If not approved, what is the next action/recommendation for further action? Reviewed by , on Time spent in review: SECOND REVIEW/UPDATE: Reviewed by on Time spent in second review: THIRD REVIEW/UPDATE: Reviewed by on Time spent in third review: Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment Page 2 of 2 Form Effective June 2008 Mason County Department of Community Development Submittal Checklist For a Geotechnical Report Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not applicable, the report should explain the basis for the conclusion. Applicant/Owner ' , _ii IAo I0 S 0 l 11 SV h Parcel# 1 .Z Z 2 1qf 50 01 0Q 2 Site Address F 7071 L C-9" t4-t-, you -30Z ge tru,r (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) -6- (b) A discussion of specific soil types Located on page(s) 6 (c) A discussion of ground water conditions Located an 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) (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) /C; j (2) A site plan which identifies the im orfant development and geologic features. Located on Map(s) ,fie, P�o (A402,R (3) Locations and logs of exploratory holes or probes. Located on Map(s) U / ( (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)�x'©lo /I4ai3) (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and Which incorporates the details of o, d rade changes. Located on Map(s) Se: J Yrat Ie �A Age, C J (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) l2 , / 101, X � (7) (a) Appropriate restrictions on placement of drainage features Located on page(s) 14 (b) Appropriate restrictions on placement of septic drain fields Located on page(s) /4 (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) 7, 9 Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the propert . 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) 13 (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) /i�/A (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, landsljdes and harmful construction methods. Located on page(s) N/4 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) /S (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) %3, (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 existing an proposed development on the site. Located on Map(s)_ P,IQyl 1, ri 11 ca cA yd e, 1544t4i hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geotogical engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. t also certify that the Geotechnical Report, dated of �. t- , and entitled &ea-ec�6'ca t X ee r+ -vr +Cho(U C, T_4 n 50 n S C^ rmeets all the requirements of the Mason County Resource Ordinance. 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) X, CLYDE S WAS Cn 43045 w fib FC1CTgCi� <v Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. 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.....................................................................................................................4 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 3.31 Groundwater......................................................................................................................... 6 3.4 SOILS TESTING.............................................................................................................................6 4.0 ENGINEERING ANALYSES,CONCLUSIONS AND RECOMMENDATIONS.........................7 4.1 BUILDING FOUNDATION RECOMMENDATIONS..............................................................................7 4.L I Bearing Capacity.................................................................................................................. 7 4.1.2 Settlement............................................................................................................................. 7 4.L3 Concrete Slabs-on-Grade......................................................................................................8 4.2 LATERAL EARTH PRESSURES........................................................................................................8 4.3 EARTHWORK CONSTRUCTION RECOMMENDATIONS....................................................................8 4.3.1 Excavation............................................................................................................................8 4.3 2 Placement and Compaction of Native Soils and Engineered rill..........................................9 4.3.3 Retaining Wall BackfiU...................................................................................................... 10 4.3.4 Wet Weather Considerations............................................................................................... 10 4.4 SLOPE STABILITY....................................................................................................................... 10 4.4.1 Slope Stability Assessment and Analysis............................................................................. 12 4.4.2 Building and Footing Setbacks........................................................................................... 13 4.5 EROSION..................................................................................................................................... 13 4.5.1 Temporary Erosion Control................................................................................................ 13 4.5.2 Permanent Erosion Control................................................................................................ 14 4.6 SURFACE AND SUBSURFACE DRAINAGE...................................................................................... 14 4.6.1 Septic Drainfield Impacts.................................................................................................... 14 4.7 VEGETATION BUFFER AND CONSIDERATIONS............................................................................. 15 4.8 ON-SITE AND OFF-SITE IMPACTS............................................................................................... 15 4.9 SEISMIC CONSIDERATIONS AND LIQUEFACTION......................................................................... 15 4.9.1 Liquefaction........................................................................................................................ 15 5.0 CLOSURE...............................»....................................................................................................16 Appendix A-Site Plan Appendix B-Geologic Map Appendix C-Soil Information(Soil Profile; Soil Logs;Well Reports) Appendix D-Slope Stability Input&Output Appendix E—Erosion Control 1.0 INTRODUCTION Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a single family residential property located at 4671 E State Route 302, identified as parcel number 12228 50 02002, 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,Nick Johnson, on August 28, 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 planned development consists of a 1- or 2-story single family residence, driveway and other ancillary features typical of this type of development. Sewer will be served by a system designated for public use. Foundation construction is expected to consist of continuous strip footings with concrete slabs-on-grade. 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; Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 1 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 • 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 Nick Johnson Geotechnical Report 74 NE Hurd Road page 2 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 2.0 SURFACE CONDITIONS Information pertaining to the existing surface conditions for the Project was gathered on August 28, 2009 by Michael Staten,geotechnical engineer with Envirotech. During the site visit,the type of geotechnical investigation was assessed, and site features were documented that may influence construction and slope stability. This Surface Conditions Section provides information on general observations, vegetation, topography, drainage and slope/ erosion conditions for the Project and surrounding areas that may impact the Project. 2.1 General Observations The property is accessed from State Rout 302, an existing paved roadway. The Project is currently developed land with a single family residence. The property is mostly cleared and flat, which was reportedly used as a pasture. State Route 302 borders the west property line,and North Bay is located approximately 300 feet west of State Route 302. Beyond the property, rural residential development exists. Vegetation on and near the Project consists primarily of 2°a or 3`a growth firs, maples, poplars, 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. The building location is primarily flat. Minor descending grades are located between the highway and North Bay, and are insignificant to this Project. 2.2.1 Upslope Geomorphology and Water Bodies Immediate ascending grades are located to the southeast of the planned development. The most critical portion of this slope consists of a 166%grade with a vertical relief of about 22 feet. This slope tapers to a zero vertical height at a distance of over 60 feet from the most critical portion of the slope. Beyond the top of this slope is an approximate 15-foot bench utilized as a roadway with moderate ascending slopes beyond. Other ascending grades of up to nearly 90% are located within 300 feet of the Project. Based on the topography,these other slopes will not influence the planned development. The Project is situated in a valley, and the upland area is a hillside. Additional geomorphology that is pertinent to both upslope and downslope areas are provided in the Subsurface Investigation Section of this report. There is an apparent water body located upslope from the planned development. This water body feeds a stream located approximately 60 feet to the north of the proposed home. Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 3 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph, 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 2.3 Surface Drainage Stormwater runoff originating upslope from the anticipated development is expected to be minimal to moderate. Runoff is mostly diverted away from the property due to accommodating topography. Excessive scour, erosion or other indications of past drainage problems were not observed within the immediate vicinity of the planned development. There were no adverse affects from the nearby stream observed near the location of the planned residence. It has been reported that stream flooding has not caused problems to the existing residence. Available FEMA maps do not depict flood problems for the proposed development. 2.4 Slope and Erosion Observations The slope grades near the Project signal a potential landslide or erosion hazard area. Some indicators that may suggest past slope movements include: • Outwash of sediments near the bottom of the slope, • Fissures, tension cracks, hummocky ground or stepped land masses on the face or top of the slope, and parallel to the slope, • Fine, saturated subsurface soils, • Old landslide debris, • Significant bowing or leaning trees, or, • Slope sloughing or calving. The nearby ascending slope showed signs of surface erosion. However, 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. 4 � A T22N RIW Aerial Photo From USDA Natural Resources Conservation Service Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 4 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 September 8,2009 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the Project was primarily gathered on August 28, 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 5 feet below the existing ground surface. Information on subsurface conditions also included reviewing geological maps representing the general vicinity of the project, and water well reports originating from nearby properties. One bulk sample was collected at the Project site at approximately 18 inches below the existing ground surface near the anticipated building location. The soil sample collected was secured and transported for possible laboratory testing. Envirotech measured the relative density of the near-surface in-situ soils by gauging the resistance of hand tools. Within testing locations, field testing results generally indicated loose to medium dense soils in the upper 18 inches, and medium dense soils from 24 inches to the depth of terminus. 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 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 outwash, Qga. Glacial Outwash is typically described as "glaciological sand and gravel and latchstring clay, silt, and sand deposited during the advance of glaciers; sandy units commonly thick, well sorted, and fine grained, with interlayered coarser sand, gravel, and cobbles and silt rip-up lag deposits at their base;may contain no glacial sediments;generally overlain by till." Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 5 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 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 indications of borrowed fill in the ascending slope used as a roadway. This fill does not pose a threat to the development. For engineering purposes, Project soils consist of distinguishable layers, as presented below. Bearing Soils - Soils within the upper 2 feet of natural ground were observed to be moist, brown Poorly Graded Sand (SP) with some silt and traces of gravel. Soils between 2 feet and 5 feet below the ground surface was observed to be grey with discoloration, and have a similar gradation as the overlying layer. Ascending Slone - Soils within the ascending slope were observed to be a dense, brown Silty Sand with Gravel(SM). 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 Indianola Loamy Sand, Ia, with 0 - 5% slopes, and Rough Broken Land, Rb. 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 approximately 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. However, soil discoloration indicates potential seasonal groundwater at depths of about 2 feet below the ground surface. 3.4 Soils Testing The soil samples obtained at the Project site during the field investigation were preserved and transported for possible laboratory testing. Visual classification of soils was performed in the field at all observed soil profiles. Visual classifications were performed in accordance with the American Standards for Testing and Materials (ASTM D2488). The general results from the visual classification are presented above in the Subsurface Conditions Section. Specifically, soils within the upper 5 feet in one testing location consisted of approximately 5%gravel, 90%sand-sized soils, and 5%silt with low plasticity. Minor variations observed during the visual classification of particle size content (i.e. gravel, sand, fines), or isolated pockets within the soil stratification were insignificant in relation to the overall engineering properties of the soil. Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 6 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 _. , , ,. :: _ z .. ... - -. .. _ •_ 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 none to low 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 24 inches below the existing ground surface. Foundation recommendations are made available based on adherence to the remaining recommendations that are provided in this report. Alterations to the aforementioned foundation recommendations may be completed upon a site inspection by a geotechnical engineer after the foundation excavation is completed. 4.1.2 Settlement Total and differential settlement that a structure will undergo depends primarily on the subsurface conditions, type of structure, amount and duration of pressure exerted by the Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 7 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 i 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 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 6 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 foundation depth are loose, saturated, or otherwise incompetent due to inappropriate land Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 8 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 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. After excavating for the foundation, the upper undisturbed native soils within the excavation should be prepared by densification with heavy construction equipment. Additional material may be required upon compaction. 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. F❑❑TING COMPACTED NATIVE SOILS OR ENGINEERED 1 FILL I 1I UNDISTURBED SUBGRIA 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 12 inches for Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 9 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 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. 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 Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 10 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 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 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: ;s Proj ect s 1 w I 1 L . 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 near terrain labeled `highly unstable' and `highly erodible' relating to soils. A Resource Map from the DNR website for the general area of this Project is provided below: Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page I 1 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County,Washington Fax: 360-2754789 September 8,2009 l' J k 72 it Y 4170.4618 � } 20 .a; L 20 Project ,7 08 170 00 27 4 r +i/ B Pupet Sou ud —` Z4 1704680 1704088 i 78 a �O Resource Map from Washington State Department of Natural Resources Website 4.4.1 Slope Stability Assessment and Analysis The Simplified Bishop Method, utilizing `STABLE' software, was used to analyze the static stability of the site slopes. Seismic conditions were estimated utilizing worst case scenario values from the static analysis, a quasi-static analysis coefficient of at least 0.15, and applying the applicable values to STABLE software. Various radii's and center points of the circle were automatically selected, and produced factor of safeties in a graphical and tabular format. Worst case scenario values were used in the slope stability analysis in regards to topography, surcharges, water content, internal friction and cohesion of the site soils. STABLE software has been repeatedly checked with manual calculations, and consistently proved to be a very conservative program. The following soil properties were used in the analysis, and are based on observed conditions, known geology, and/or published parameters: Ascending soils • Soil unit weight: 138 pcf • Angle of internal friction: 36 degrees • Cohesion: 100 psf Envirotech Engineering Nick Johnson Geotechmcal Report 74 NE Hurd Road page 12 4671 E State Route 302 BeHair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 September 8,2009 Based on the slope stability analysis, a minimum factor of safety was determined to be 0.9 relative to static slope failures, and 0.7 with relation to seismic conditions. See the slope stability information in Appendix D for a depiction of input parameters and example of outputs. Although landslides are known to occur in this area, DNR did not indicated previous landslide activity on or near the Project. However, Project soils exhibit different characteristics than areas with previous landslide activity. The slope stability analysis was very conservative due to the level of geotechnical investigation. Due to the relatively small vertical relief and upslope benching, an adequate building setback is sufficient for this Project. It is our opinion that the proposed development should occur in accordance with this geotechnical report. 4.4.2 Building and Footing Setbacks Due to potential debris flow, the building location should have a minimum setback from the local ascending slope toe equal to about %Z the slope height. The toe of the ascending slope is delineated as a grade break in which the ascending slope is in excess of 40%. Envirotech recommends the building setback to be at least 10 feet from the toe of the nearby ascending slope. See the Geologic Map in Appendix B for an illustration of the setbacks. The required setbacks may be reduced, if necessary. The setback for ascending slopes may be decreased by performing a higher level geotechnical analysis, utilizing retaining walls or buttressing the slope toe. 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. Specifically, steep slopes should be left undisturbed, and all construction activity will occur on nearly flat ground. 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, straw matting is presented in Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 13 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County. Washineton this report as the first choice for temporary erosion control. In addition, open utility trenching should be limited to no more than 300 feet at a time during the wet season. Any erosion control should be located down-slope and beyond the limits of construction and clearing of vegetation where surface water is expected to flow. If the loss of sediments appears to be greater than expected, or erosion control measures are not functioning as needed, additional measures must be implemented immediately. See Appendix E for sketches and general notes regarding selected erosion control measures. The Site Map in Appendix A depicts the recommended locations for erosion control facilities to be installed, if necessary. 4.5.2 Permanent Erosion Control Permanent erosion control may also be necessary if substantial vegetation has not been established within disturbed areas upon completion of the Project. Temporary erosion control should remain in place until permanent erosion control has been established. Permanent erosion control may include promoting the growth of vegetation within the exposed areas by mulching, seeding or an equivalent measure. Selected recommendations for permanent erosion control are provided in Appendix E. Additional erosion control measures that should be performed include routine maintenance and replacement, when necessary, of permanent erosion control, vegetation, drainage structures and/or features. The following Surface and Subsurface Drainage Section may have additional recommendations with relation to permanent erosion for surface drainage features. 4.6 Surface and Subsurface Drainage Positive drainage should be provided in the final design for all planned residential buildings. Drainage shall include sloping the ground surface, driveways and sidewalks away from the Project structures. All constructed surface and subsurface drains should be adequately maintained during the life of the structure. If drainage problems occur during or after construction,additional engineered water mitigation will be required. This may include a combination of swales, berms, drain pipes, infiltration facilities, or outlet protection in order to divert water away from the structures to an appropriate protected discharge area. From a geotechnical perspective, both perimeter footing drains and roof drains are optional for the single family residence. If roof drains are not utilized, splash blocks should be placed at all downspouts. If footings are established at depths greater than 2 feet below final grade, then perimeter footing drains are recommended. If utilized, subsurface water intercepted in the perimeter footing drains, and stormwater collected from roof drains shall be tight-lined to an appropriate infiltration area or outlet protection area located downslope and at least 15 feet from any structure. In addition, drainage outlets shall not be within any of the recommended building setbacks or vegetation buffers that are provided in this report. 4.6.1 Septic Drainfield Impacts On-site septic drainfields are not anticipated for this Project. This property is served by a sewer system. Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 14 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 4.7 Vegetation Buffer and Considerations Vegetation is an excellent measure to minimize surficial slope movements and erosion on slope faces and exposed surfaces. By removing trees, the root strength is decreased over time, thereby lowering the `apparent' cohesion of the soil. Transpiration is decreased, which results in additional groundwater, increased pore water pressure and less cohesion/ friction of the soil particles. Stormwater runoff also increases, and, fewer plants will create less absorption of the force from raindrops,thereby creating the potential for erosion hazards. Vegetation shall not be removed from the face of the steep slope. However, any tree deemed hazardous to life or property shall be removed. If tree removal is necessary,then stumps and roots shall remain in place, and the underbrush and soil shall remain undisturbed as much as possible. 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 E, corresponding to the International Building Code (IBC) soil profiles. According to the IBC, the regional seismic zone is 3 for this Project. The estimated peak ground acceleration ranges from 0.50g to 0.60g. This estimation is based on the United States Geological Survey(USGS)National Seismic Hazard Project in which there is an estimated 2% probability of exceedance within the next 50 years. There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this property is the Tacoma Fault Zone, in which is approximately 1 mile 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 to moderate for this Project. Although a significant poorly-graded sand layer is present within the upper 50 feet of the subsurface soils,various conditions alleviate the hazard for liquefaction. These conditions include the lack of a permanent shallow water table. Free flowing groundwater exhibits less pore pressures within the soil than confined groundwater, or soils below a water table. Less pore water pressures are beneficial for a lower liquefaction potential. Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 15 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 September 8,2009 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, Envirotel Engineering - Michael Staten, P.E. Geotechnical Engineer Envirotech Engineering Nick Johnson Geotechnical Report 74 NE Hurd Road page 16 4671 E State Route 302 Belfair,Washington 98528 Parcel 12228 50 02002 Ph. 360-275-9374 Mason County, Washington Fax: 360-275-4789 September 8,2009 APPENDIX A SITE PLAN SCALE- 1 INCH = 50 FEE 0 25 50 APPRpXIMA�E S1 RE AM LpC AT ION PROPERTY LINE EXISTING SINGLE FAMILY PROPOSED RESI ENTAL RESIDENCE (APPROXIMATE) gp STRUCTURE CAP R'Q,�MATE) LL 0 TEMPORARY ER❑SI❑N TPI' OF L AL SLOPE CONTROL IF NECESSARY--� 2% X 9T 2 XCEE G 40% X A X TP1� 'VA TOE OF SLOPE �0 EXCEEDING �40% "'� WAY cAPP XIMAIE) 3713 1NG T DRIv E � E 1 W 0 N PROJECT/ OWNER/ LOCATION- SINGLE FAMILY RESIDENCE NOTES �o GE❑TECHNICAL REPORT 1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. GENERAL LOCATIONS ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE N. JOHNSON GEOTECHNICAL REPORT, PARCEL 12228 50 02002 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. ++ +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 _jLjq TEST PIT SITE PLAN PROPERTY LINES. APPENDIX B GEOLOGIC MAP A . . SCALE, 1 INCH = 50 FEE S❑ILS: LOOSE TO DENSE POORLY 25 50 GRADED SAND AND SILTY SAND WITH E STREAM L13CATI�N GRAVEL OVER VERY DENSE ❑UTWASH CONGLOMERATE AppRpXIMAT PROPERTY LINE--�_ EXISTING SINGLE FAMILY PROPOSED RESIPENTAL RESIDENCE <APPR❑XIMATE400FT} STRUCTURE A PR XIMATE) LL / o SIDE OF /T ❑F L AL SLOPE CRITICAL SLOPE / XCEE G 40% 2% 9T 2 v� TOE OF SLOPE TP EXCEEDING 40% PPR�XIMATE) 0 3�pF T+_ �RIv EW AY �n EXISTING w VEGETATION SH-A" NOT RE--- N REM❑VE FROM FACE ❑E CRITICAL SLOPE EXCEPT AS 10FT BUILDING SETBACK FROM --PERMITTED IN GEOTECHNICAL TOE OF 40%+ SLOPE REPORT (SEF�EOTECHNICAL REPORT) 0 9• / • O PROJECT/ OWNER/ LOCATION SINGLE FAMILY RESIDENCE NOTES- GE❑TECHNICAL REPORT 1. ALTERNATIVES FOR REDUCING BUILDING SETBACKS OR VEGETATION N, JOHNSON BUFFERS MAY BE PROVIDED IN THE GEOTECHNICAL REPORT. PARCEL 12228 50 02002 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, 3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATION ENVIROTECH ENGINEERING OF PROPERTY LINES AND SITE FEATURES, SUCH AS TOP OF SLOPES, WATER -a SLOPE INDICATOR 74 NE HURD ROAD FEATURES, ETC.., WITH RELATION TO THE PROPERTY LINES MUST BE BELFAIR, WASHINGTON 98528 VERIFIED BY THE OWNER, RECOMMENDATIONS IN THIS REPORT PROVIDE 80 EXISTING CONTOUR 360-275-9374 PSETBACKS,ROPERTY LINETHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT TPl TEST PIT GE❑L❑GIC MAP APPENDIX C SOIL INFORMATION VERTICAL AN➢ HORIZONTAL SCALEi I INCH = 40 FEET 0 10 20 40 DRIVEWAY PROPOSED HOUSE FILL EXISTING GRADE ,mob SILTY SAND WITH GRAVEL FINE SAND AND CONGLOMERATE VERY DENSE ❑UTWASH SECTION A-A PROJECT/ OWNER/ LOCATION- SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT NICK JOHNSON PARCEL 12228 50 02002 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 LOGOS), AND/OR EXPERIENCE IN THE GENERAL AREA. SOIL PROFILE TEST PIT LOG TEST PIT NUMBER TP-1 PROJECT: SFR Geotechnical Report DATE OF LOG: 8/28/2009 PROJECT NO: 0970 LOGGED BY: MCS CLIENT: N. Johnson EXCAVATOR: N/A LOCATION: Parcel 12228 50 02002 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 Brown, moist, loose to medium dense SILTY SAND with GRAVEL. Gravel is primarily well-graded and subangular. 1 Sand is mostly well-graded. Low plasticity. 2 3 4 5 - Excavation terminated at approximately 5.0 feet 6 7 8 9 10 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this baring 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: 8/28/2009 PROJECT NO: 0970 LOGGED BY: MCS CLIENT: N. Johnson EXCAVATOR: N/A LOCATION: Parcel 12228 50 02002 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 Brown, moist, loose POORLY GRADED SAND with some silt and traces of gravel. _ Sand is mostly fine. None to low 1 plasticity. Medium dense 2 x' Grey Some discoloration 3 4 5 - Excavation terminated at approximately 5.0 feet 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. WATER WELL REPORT. CURRENT Original&1'copy—Ecology,3id copy—owner,3"•°copy—driller Notice of Intent No. W 236134 Construction/DecotnInission("x"in circle) Unique Ecology Well ID Tag No. ®Construction Water Right Permit No. O Decommission ORIGINAL INSTALLATION Notice Property Owner Name Tom Johnson -73 of Intent Number Well Street Address E 4671 HWY 392 PROPOSED USE: [}Domestic ❑ Industrial ❑ Municipal City Belfair County Mason ❑ Dewater ❑ Irrigation ❑Test Well ❑ Other EWM LocatiorNE 1/4-1/4 NW I/4 See� Twn�2 R�[l Or arao TYPE OF WORK:.Owner's number of well(if mDre than one) wwsa IN New well O Reconditioned Method:❑ Dug ❑ Bored ❑ Drivin Lat/Long(s,t,r Lat Deg Lat Min/Sec ❑ Deepened ER Cable ❑ Rotary ❑ Jetted DIMENSIONS: Drtrneterofwell_�_inches,drilled Qn e. Still REQUIRED) Long Deg Long Min/Sec Depth of completed well CONSTRUCTION DETAILS Tax Parcel No. 12228-50-02002 Casing' (k Welded �_" Diam.from +1 It to 85 ft. Installed: ❑ Liner installed Diam from fl.to_ e. CONSTRUCTION OR DECOMMISSION PROCEDURE ❑ Threaded Dism.from fl.to ft. Perforations: O Yes �I No Formation Describe by color,character,size of material and structure,and the kind and mire of the material in each stratum penetrated,with at tenet one entry for each change of Type of perforator used _ information. USE ADDITIONAL SHEETS IF NECESSARY. SIZE of perfs in by in.and too,of perfs_fmm—ft to ft. MATERIAL FROM TO Screens: Yes ❑ No 1p K-Pac Location 83- Manufachm'sNam Tnbn-rut Top soil Type 3taillle88 Model No. Diam. Slot size_ Q_fmm 85 ft.to 9() ft. Diann Slot size from ft,to ft. brown cla V 2 25 Grovel ilter packed: ❑ Yes Z No ❑ Size of gmvel/sand Materials placed from ft to ft. Blue gray cemented surfsce Seal: 19 Yes ❑ No To what depth? 20 ft. Material used in seal Rptnni t-a Greenish brown silt bound crrarel Did any strain contain unusable watcO ❑ Yes 2 No Type of water? Depth of strata Relish brown clay & gravel 38 83 Method of sealing$trata off PUMP: Manufscttrer'sNarw I Sand & gravel with water 83 90 Type: sub H.P. WATER LEVELS: Land-surfacd elevation above mean sea level ft. Static level .24 fl.betow top of well Date Artesian pressure Ibs per square inch Date Artesian water is controlled by' (cap.valve etc. -WELL TESTS: Drawdown is amount water level is lowered below static level Was a pump test made?❑ Yes R No If ves,by whom? Yield: >Tel./ruin.with ft drawdown after hrs. Yield:_ ------- with ft drawdown after hrs. Yield- Rat./min with a.drawdown after bra. Recovery data(time taken as zero when pump turned oM(wafer level measured from well top to seater level) r, Time Water Level Time Water Level Time Water Level le VWJ Date of test 0 Bailer test_-gyp_galJnan.with ft.drawdown after_4___hrs. Airtcst gal./min with stem set at ft.for hrs. Artesian Dow g.p m. Date Temperature of water Was a tdiemical analysis made? ❑ Yes R No Start Date 5/1$/07 Completed Date 5/30/07 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. R Driller❑Fngineer ❑Trainee N ( Drilling Company DaUi q Dri I 1 i nq Driller/EngrneerffraineeSignature Address '340 NE n)ayj c Parm Ra Driller or trainee License No. 967 city,state,zip Rel fa i r, WA 9A 52A If TRAINEE, Contractor's Driller's Licensed No. Registration No. DAVI SDI 11 OoA Date May07 Drilier's Signsture - Ecology is an Equal Opportunity Employer. ECY 050-1-20(Rev 3/05) The Department of Ecology does NOT warranty the Data and/or Information on this Well R >.,�, { - ., ;., { � ,... : a x _' - 1 - 5 .. ,.5 L' �� 9 .� — r f3 i - .. ,,. a. '�' +1 a � I `t .. _ - � t - .. ram`p_ ,.. � _ ..., r .. _t r � _ � f ) t � .. �. .. �� .. .... .� � � � ' _ , ♦ 1 <e. � .. .m, .<. ... ' ...,. .,... e ._.� ... c �Z'L� .�. .. " i a, — - t y -5' _ ,_ , � I APPENDIX D SLOPE STABILITY STABLE Slope Stability Analysis System New User Project Nick Johnson Datafi(e: Dynamic Bishop STABLE Version 9.03.00u Bishop +x+xxa+a+aa+++++++xawx+a++a+++x++a+a++++++x+x++++++++++axx TITLE Dynamic a+a++a+++++x+x++a+++++++++++++++aat+++x++a+++++++++++x+aaa UNITS (Metric/Imperial) I +++++++++a+++xa++++a++++aax+++a+++++x++++x+x++++++x+++xxa+ GEOMETRY DEFINITION POINTS NO. X Y 1 0.000 0.000 2 50.000 0.000 3 63.000 22.000 4 78.000 22.000 5 103.000 32.000 6 10.300 0.000 7 14.640 0.000 8 18.970 0.000 9 23.310 0.000 10 27.650 0.000 11 31.980 0.000 12 36.320 0.000 13 40.660 0.000 14 44.990 0.000 15 49.330 0.000 16 53.670 6.210 17 58.010 13.550 18 62.340 20.890 19 66.680 22.000 20 71.020 22.000 21 75.350 22.000 22 79.690 22.680 23 84.030 24.410 24 88.360 26.150 25 92.700 27.880 LINES Lo X Hi X SOIL 1 2 1 2 3 1 3 4 1 4 5 1 +++a+++++++++++++++++a++a+++++aa++a+aa+++++x+axx++t+++a+++ SOILS SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT. 1 Soil-1 CONTINUOUS-BLACK 100.00 36.0 138.000 x+x+a+a+x+a++++xx++++a+a++++++aa+x+a++++a++++aaaa+++++ax++ PORE PRESSURE SPECIFICATION STABLE02002 MZ Associates Ltd Printed on: 05/09/09 @ 10:32:27 Page: 1 STABLE Slope Stability Analysis System New User Project : Nick Johnson Datafile: Dynamic Bishop SOIL PIEZO RU EXCESS Y/N/P Value Value 1 N 0.000 0.000 PIEGOMETRIC SURFACE POINT POINT PORE PRESSURES POINT PRESSURE +++++++w+++++++ww++++++++++++++a+++a+w+w++++++ww+++a++++++ SLIP DIRECTION (+/— X) SLIP—CIRCLES AUTOMATIC Circle Centre Grid Extremities 114.400 +ww++++++aw+www 10.300 * * 92.700 +++++++++++++++ 32.000 X spacing -- no. of cols (max 10)— 10 Y spacing -- no. of rows (max 20)— 20 Grid 1 Circles through point 6 Grid 2 Circles through point 7 Grid 3 Circles through point 8 Grid 4 Circles through point 9 Grid 5 Circles through point 10 Grid 6 Circles through point 11 Grid 7 Circles through point 12 Grid 8 Circles through point 13 Grid 9 Circles through point 14 Grid 10 Circles through point 15 Grid 11 Circles through point 16 Grid 12 Circles through point 17 Grid 13 Circles through point 18 Grid 14 Circles through point 19 Grid 15 Circles through point 20 Grid 16 Circles through point 21 Grid 17 Circles through point 22 Grid 18 Circles through point 23 Grid 19 Circles through point 24 Grid 20 Circles through point 25 STABLE02002 MZ Associates Ltd Printed on: 05/09/09 @ 10:32:27 Page: 2 0 0 0 0 0 0 0 0 0 0 0 N 0 � � 0 0 � �0 .0 � EaD 0j 0 -C c � m 0 mm o W o 0 .. a N U 0 v o N 0 1 W � OCm a n � Qm 0 0 0 0 0 0 0 0 0 0 0 0 Nn 't 0 1\ 00 0 rll n c 0) 0 0 c 0 � aD U 0, - � 4m .. Q N U = U1"o N `- m o L 0 Cm Q 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 2 6 FT MAX. O.C. 0.5 FT BOTTOM OF TRENC4FENCE BEFORE PLACING 2'x2'x5' WOOD POST OR ��--- 6 FT 12' DEEP, B' VIDEQUIVALENT OR BETTER EXISTING FILLED WITH 3/4T GROUND SURFACE 2 T WASHED GRAVELi DIRECTION OF �FT 12' DEEP, 8' WIDE EXISTING TRENCH FILLED WITH i T WATER FLOWGROUND SURFACE 3/4' TO 1 1/2' 2.5 FT 5 FT WASHED GRAVEL BOTTOM EXTENTS OF crLT FENCE - DETAIL GEOTEXTILE FABRIC 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 HESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR FEET OF GROUND. HALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. 3. MINIMUM THICKNESS SHALL BE 2 INCHES. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE 4. HAY OR STRAW IS SUBJECT TO BLOWING. KEEP MOIST OR TIED NSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. DOWN. 3. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN LACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED. PERMANENT EROSION CONTROL NOTES, EMPORARY EROSION CONTROL NOTES- SEEDING FOR RAW SLOPES OR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND 1, BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES, ERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE SWALES, LEVEL SPREADERS AND SEDIMENT BASINS. MMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE, ROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS ACCROS LONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH OR PERPENDICULAR TO THE SLOPE. EPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF 3, SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE HE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING APPLIED AT THE RATE OF 120 POUNDS PER ACRE. [RY OTHER APPROVED TREATMENT. 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO SEASON (MAY 1 THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE FOSTER AN➢ PROTECT THE ROOT STRUCTURE. MOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO 5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30, LY 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 ❑THERWISE DISTURBED , GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING). Y NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' TABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL RECOMMENDATIONS. AMOUNTS SHOULD BE MINIMIZED, ESPECIALLY REAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ADJACENT TO WATER BODIES AND WETLANDS. HROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, REE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION LAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE. ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE RFORMED DURING THE FOLLOWING PERIODS- MARCH 1 TO MAY 15, AND AUGUST 15 TO PROPORTIONS PURITY GERMINATIO CTOBER 1. SEEDING AFTER OCTOBER I VILL BE DONE WHEN PHYSICAL COMPLETION NAME BY WEIGHT(%) (X) (X) IF THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE O SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT REDTOP (AGROSTIS ALBA> 10 92 90 OSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90 LASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN CHEWING FESUE 40 97 80 EPTEMBER 30. (FESTUCA RUBRA COMMUTATA) (JAMESTOWN, BANNER, SHADOW, KOKET) N THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT WHITE DUTCH CLOVER 10 96 90 CTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE (TRIFOLIUM REPENS> WNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION NO 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 REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED GREATER THAN 2,1 (HORIZONTAUVERTICAL). TO 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 TRANSPORT 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 ❑THERWISE 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 LT COVER IN AND OF THEMSELVES. IN THE EVENT THAT ANY LAND AREA NOT ING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY TABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON HE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL MMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN PPROPRIATELY PROTECTED OR STABILIZED. ILT FENCE PROJECT/ OWNER/ LOCATION GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE 'STORMWATER MANAGEMENT MANUAL SINGLE FAMILY RESIDENCE OR THE PUGET SOUND BASIN,' OR APPLICABLE COUNTY STANDARDS . GEOTEXTILE FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO THE LENGTH OF GE❑TECHNICAL REPORT ACH BARRIER TO AVOID USE OF JOINTS. IF JOINTS ARE NECESSARY, FILTER FABRIC SHALL BE SPLICED NICK JOHNSON OGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT PARCEL 12228 50 02002 OTH ENDS TO THE POST. MASON COUNTY, WASHINGTON . STANDARD FILTER FABRIC SHALL BE FASTENED USING V STAPLES OR TIE WIRES (HOG RINGS) E 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 EQUIVALENT. 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. ER❑SI❑N CONTROL 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: 1 L6a&o 4-0&yy� Permit# 6C>-hn41 - 00,543 Parcel# �2" '' 5-V 0 �7 vo Date(s)o the Documents)reviewed.: (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, OK? Comment: (b) A is ssion of specific soil types OK? jZ Comment: (c) A discussion of ground water conditions OK? y Comment: (d) A disc Sion of the upslope geomorphology OK'. Comment: (e) A disc sion of the location of upland waterbodies and wetlands OK?Comment: (f) A discussion of history of landslide activity in the activity in the vicinity, as available in the referepc6d maps and records OK? Comment: (2) A site pla hich identifies the important VeVelopment nd geologic features. OK? Comment: (3) Locations Ad logs of explorat s or OK? Comment: (4) The a a of the proposed developmerft, the boundaries of the hazard, and associated buffers and setbacks stiall be delineated(top, both Sid s, and to ,,)on a geologic ma of the site. OK?__X Comment: (5) A minimum of one cross section at a cale which a4equately depiclK the subsurface profile, and which incor ro o orates the details s grade changes. OK?Comment: (6) A description and results of sl6pe'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 safe factor is 1.1. and the quasi-static analysis coeffients should be a value of 0.15. OK? Comment: (7) (a)Appro_pyi a restrictions on placement of drainage features OK? Comment: (b) Approp ' to restrictions on placement of septic drain fields OK? C mment: (c) Appro ate restrictions on placement of compacted fills and footings OK? Comment: (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Page 1 of 2 Form Effective June 2008 OK? Comment: (e) Recommended setbac fr m the landslide hazard areas shoreline bluffs and the tops of other lopes on the property. OK? V Comment: f{ (8) Recommendations for the preps ation 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 egetation removal. OK? Comment: (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies t,0 specific mitigating measures to be implemented during construction to protect the slope floph erosion, landslides and harmful construction methods. OK? V Comment: (10) An analys' of both on and off-site impacts of the proposed development. OK? Comment: (11) Specifications of final development conditions such as, vegetative management, drainage, erosion cpntrol, and buffer widt , Is- OK? r/ Comment: (12) Recommend tions for the pr aration 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 natur�of existing and prop os d d velop nt on the site. OK? f/ Comment: 44 Are the Documents signed and stamped? ,�i 2 � Type and #of License: �i "I�1 J Lc < If not approved, what is the next action/recommendation for further aiction?A91(& Reviewed by , on Time spent in review: SECOND REVIEW/UPDATE: Reviewed by on Time spent in second review: THIRD REVIEW/ UPDATE: Reviewed by on Time spent in third review: Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment Page 2 of 2 Form Effective June 2008 I Mason County Department of Community Development Submittal Checklist For a Geotechnical Report Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not applicable,the report should explain the basis for the conclusion. T Applicant/Owner. V, �IAo(c S J o �115Vn Parcel# / Z Z 2� rJ0 C2002 Site Address 7 5-jr T� Po c. e '0 (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) S (b) A discussion of specific soil types Located on page(s) 6 (c) A discussion of groin water conditions Located on page(s) (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) %C. 11 (2) A site plan which identifies��important development and geologic features. Located on Map(s) S, oY) (Aor/ (3) Locations and logs of explorator holes or robes. Located on Map(s) a ff (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) /14up ?,4�,,, 3) (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) !;;2, I -o4-,je (14,919, C (6) A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures.The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5,the minimum seismic safety factor is 1.1. and the quasi-static analysis coeffients should be a value of 0.15. Located on page(s) l2 (7) (a)Appropriate restrictions on placement of drainage features Located on page(s) 14 (b) Appropriate restrictions on placement of septic drain fields Located on page(s) 14 (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) 7, 9 Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) /S (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) /3 (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) ;lilA (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, landsl)'des and harmful construction methods. Located on page(s) A114 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) /-5' (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) 13, /t /S (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 existing an proposed development on the site. Located on Map(s) s Mav, CLOD, f{ C_ yoe, ,544f_*, hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnicaVgeoiogical engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditkms. I also certify that the Geotechnical Report, dated—T� 20C9 , and entitled dfech tea_ I /�eer. + �r c h o I U� Tv6)n 50 n ��fideFu rn,14 R-e r i - meets all the requirements of the Mason County Resource Ordinance, 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) !0, CLYDE S pF WASly Tq;N ? 43045 k, �A �FCIST6R�� SS�ONALti�O` Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.