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GEO2013-00028 - BLD Engineering / Geo-tech Reports - 8/1/2013
MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Planning Division P O Box 279, Shelton, WA 98584 (360)427-9670 Geotechnical ReportReview Acceptance Letter August 01, 2013 JEFF BRITTIG 241 E MERRIMOUNT RD UNION WA 98592 Case No.: GE02013-00028 Parcel No.: 322367500030 Project Description: pole building with loft located at top of slope. The Geotechnical Report for JEFF BRITTIG has been received and reviewed by the Planning Department. The report was prepared by Allan Borden dated 6/24/2013. Based on the certification provided by the licensed engineer/geologist, the referenced Geotechnical Report was prepared in general accordance with the requirements in the Mason County Resource Ordinance, Landslide Hazard Areas 17.01.100.E.5. Mason County considers the review valid until such time as scope of project, site conditions, and/or regulations change. Should the scope of work, site conditions, and/or regulations change after the original review, then an addendum from the original author of the report may be required to address these changes. The report would only be re-reviewed if a permit for development were submitted after these changes occur. Mason County does not certify the quality of the work done in this Geotechnical Report. Please contact me at (360) 427-9670, ext. 365 if you have questions. Sincerely, 14� lIf ktv--,� 'Allan Borden Land Use Planner Mason County Planning Department Comments: 8/1/2013 Page 1 of 1 GE02013-00028 �w pro ec wgr;weer�wg c,eotechvwcaL o evw�rovwKtKtat o Dra�wage°R.oaolwad July 9,2013 RECEIVED AUG 0 12013 Jeff Brittig 426 W. CEDAR ST. 241 E Merrimount Road Union,Washington 98592 RE: Geotechnical Report Addendum#1 for Brittig Single Family Residential Property,241 E Merrimount Road,Union,Parcel 32236-75-00030&-00040,Mason County,Washington Dear Mr.Brittig, Envirotech Engineering (Envirotech) has completed this geotechnical report addendum for the above referenced single family residential properties. The original report, dated June 24, 2013, was prepared by Envirotech (Project #1349). This addendum was prepared in order to provide additional information with relation to the Project and the aforementioned geotechnical report. The proposed buildings, as depicted in the geotechnical report,may be of any type or location as long as the intent of the geotechnical report is adhered to. With relation to type and location of development, specific geotechnical concerns include setbacks, drainage considerations, and precaution when building on fill soils. Footing setbacks from the small bank are delineated at 15 feet. However, setback reductions in this case may be utilized per typical standards. This allows the bottom of the footing to be at or below the 30 degree angle with relation to the base of the slope. See the attached sketch for an illustration. All drainage may follow the geotechnical report, or Mason County requirements for small parcels.Foundation recommendations shall follow the original geotechnical report. Please contact Michael Staten at 360-275-9374 if you have any questions, comments, or require additional information. Best Regards, Envirotech Engineering `S CLYDE S waskj�T�T� 43045 Fcis �� �SS�CNAL��G�� Michael Staten,P.E. Geotechnical Engineer Envirotech Engineering Geotechnical Report Addendum#1 PO Box 984 Page 1 of 1 Brittig Single Family Residential Property Belfair,Washington 98528 Parcel 32236-75-00030&-00040 Ph.360-275-9374 July 9,2013 Fax.360-2754789 N SCALE, 1 INCH = 100 FEET 0 25 50 100 SEptlG BUILDINGS DEPICTED ARE FOR ILLUSTRAITON ONLY, 'F LOCATIONS MAY CHANGE IF +++ � COMPLIANT WITH REGULATORY q Pf� H � C DES AND THE GEOTECHNICAL vep1LHpGE + Tpao EPORT, 4 } ut } 60 TPI V 80 UZ S x�xCEt:� sTR� 1205f 1 140 SEE ADDENDUM FOR SETBACK REDUCTION 160 OPTIONS 180 9 2 op OF r� 240 OX E EE SETBACKS NOT REQUIRED FOR S� ASCENDING SLOPE 260 2 0 20 VEGETATION SHALL NOT BE 300 40 CLEARED ON SLOPES WITH 30 0 GRADES GREATER THAN 40% EXCEPT AS PERMITTED BY 380 340 GEOTECHNICAL REPORT. 360 400 380 400 PROJECT/ OWNER/ LOCATION, SINGLE FAMILY RESIDENCE NOTESi 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 BRITTIG GEOTECHNICAL REPORT. PARCEL 32236 75 00030 & 00040 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 ENGINEERS REPORT. ++ +EROSION CONTROL ENVIROTECH ENGINEERING 3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATION OF PO BOX 984 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 DSO-- EXISTING CONTOUR SETBACKS, DEPTHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT TP1e TEST PIT SITE PLAN PROPERTY LINES. i VERTICAL AND HORIZONTAL SCALE. SCALE- I INCH - 60 FEET 0 1 0 60 PLANNED BLDG FUTURE BLDG ILL ,`off or FOUNDATION MUST BE BELOW FILL SOILS AND BELOW THE 30 DEGREE PLANE AS SHOWN, IF POLE BUILDING, BOTTOM OF POLES OR POLE PADS ARE CONSIDERED FOUNDATIONS, FOUNDATION MUST BE BELOW FILL SOILS PE GEOTECHNICAL REPORT SECTION A PROJECT/ OWNER/ LOCATION, NOTES, SINGLE FAMILY RESIDENCE 1. FILL SOILS MAY BE RECOMPACTED PER THE GEOTECHNICAL REPORT GEOTECHNICAL REPORT IN ORDER TO BUILD UPON, 2. 15' SETBACK MAY BE REDUCED PER FOUNDATIONS PLACED ON THIS DRAWING. BRITTIG PARCEL 32236 75 00030 6 00040 MASON COUNTY, WASHINGTON ENGINEER, ENVIROTECH ENGINEERING PO BOX 984 BELFAIR, WASHINGTON 98528 360-275-9374 PR❑FILE ATTACHMENTS 1. SITE PLAN 2. PROFILE TABLE OF CONTENTS 1.0 INTRODUCTION..................................................................................................................................I 1.1 PROJECT INFORMATION.....................................................................................................................1 1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK.........................................................................1 2.0 SURFACE CONDITIONS....................................................................................................................3 2.1 GENERAL OBSERVATIONS..................................................................................................................3 2.2 TOPOGRAPHY......................................................................................................................................3 2.2.1 Upslope Geomorphology and Water Bodies...............................................................................3 2.3 SURFACE DRAINAGE...........................................................................................................................3 2.4 SLOPE AND EROSION OBSERVATIONS................................................................................................4 3.0 SUBSURFACE INVESTIGATION......................................................................................................5 3.1 FIELD METHODS,SAMPLING AND FIELD TESTING............................................................................5 3.2 GENERAL GEOLOGIC CONDITIONS....................................................................................................5 3.3.1 Groundwater...............................................................................................................................7 4.0 ENGINEERING ANALYSES AND CONCLUSIONS.......................................................................8 4.1 SLOPE STABILITY................................................................................................................................8 4.1.1 Slope Stability Analysis...............................................................................................................9 4.1.2 Slope Stability Assessment........................................................................................................10 4.1.3 Septic Drainfield Impact to Critical Slopes..............................................................................10 4.2 EROSION............................................................................................................................................10 4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION.............................................................................1 1 4.3.1 Liquefaction..............................................................................................................................11 4.4 LATERAL EARTH PRESSURES...........................................................................................................11 4.5 ON-SITE AND OFF-SITE IMPACTS.....................................................................................................12 5.0 ENGINEERING RECOMMENDATIONS.......................................................................................13 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 5.21 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.................................................................................................17 5.4 SURFACE AND SUBSURFACE DRAINAGE...........................................................................................17 5.5 VEGETATION BUFFER AND CONSIDERATIONS.................................................................................17 5.6 TEMPORARY AND PERMANENT EROSION CONTROL.......................................................................18 6.0 CLOSURE............................................................................................................................................19 Appendix A-Site Plan Appendix B-Soil Information(Soil Profile;Soil Logs;Well Reports) Appendix C-Slope Stability Input&Output Appendix D—Erosion Control Appendix E—Drainage Details 6 o 2-00 � 1 �8 Geotechnical Report for Brittig Single Family Residential Property 241 E Merrimount Rd, Union Parcel No. 32236 75 00030 & 00040 Mason County, Washington June 24, 2013 Project#1349 Prepared For: Jeffery Brittig 241 E Merrimount Rd, Union WASL f sT9T Washington 98592 Prepared By: ti �= 2 6/uNi3 Envirotech Engineering �°,-� 'PFc,S���°G���w� PO Box 984 sS��NALEN Belfair, Washington 98528 Phone: 360-275-9374 Fax: 360-275-4789 Mason Colsnfy Departrne-rit of Community Ceveiopmenf SubmiUai .r;eciciist For a Geoi:ecnnicai Report instructions: This checklist must be submitted with a Geotecnnical Report and completed_ signed, and stamped by the licensed professional(s)who prepared the GeoiechnicaiReport for review by mason County pursuant to ffic, Mason County r esourve Vicathi alnce- If ail hail found to be not applicable, the report should explain the basis for the concli ision- App;icanUiDwner �� Parcel# Site Address 74 l Z� / ��+Y r k2ud, `ten"O '� (1) (a)A discussion of generAl-geologic conditions in the vicinity of the proposed development, Located on page(s) .7 (b) A discussions or specirjc soli types Located on pages) _G, (c) A discussion of ground water conditions Located on rages) 7 (d) A discussion of the u slope geomorphology i UL:aieO on pages) (e) A discussion of tfse location of upland waterbodies and wetlands Located on page(s) 3 _ (fj A uts cuss ioti ui iiisiory of iandstide activity in the activity in the vicinity, as available in the referenced maps and records Lcc tcd on page(s) 45' -9 (2) A site plan which identifles the important development and geologic features. Located on Map(s) S, f'( pp 4 (3) Locations and logs of exploratory h les orf p�robes- Li:E:C1lGU t)rt IV3GIplyJ) �• O' C'� ) (4) ►he area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top- bothsides, and toe)on A-geologic map of the site. Loca ed of i Mapk's) GJ, � /-'i (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details.of prppose grade changes. woeicu UO ivie}i(S) (7n'; i- [� G > (6) A description and re.—URs^.f slope stability analyses perfvrrnee us both z12fi'io ar'.d S?iSrrtlC conditions_Analysis should examine worst case-failures_The analysis should include the :, ?lif`-:d SiSI iopo'S ='v at ad o ".'k:ias_7 die-.i in imun, static safeiCy factor is D_5,the minimum seismic safet,,factor is 1.1_and the quasi-static analysis coefl'ierds should be a`aalue of 0.15. Located on pages) rt 4? • c (7) (a)Appropriate restrictions on plac-ernent of drainage features LuCaied on page(s) (b) Appropriate r ast^c:ions on placersent of septic Crain:`:elds Located on page(s) / (c) rippropridie restrictions on placement of compacted fills and footings Located on page(s) /5_ /37 Page 1 of 2 Form Effective June 2008 Disclain—jer: Mason County does not certify the quality pf the work done it this Geotechni Reno". (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on i;he properly. Located on page(s)_ /7 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other siopes on the pro erty. Located on page(s) / (i3) i iecomi-nendaiions for the preparation of a detailed clearing and grading pion which speciricBiiY identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. Located on page($) t`7 (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, iandslides and harmful construction methods. Located on page(s) l 0 (i0) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) / 'Z j) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) (7� 16 (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) (13) A site map drawn to sc-31e sholhfing the p foperty.boundaries, scale,north arrow, and the!oration and nature of existing and proposed development on the site. iuo�Eacl o�-i nK-ap(s) S�I''I��n hereby cersfy:ender peanalty of pegs mat 1 am a civu engineer licensed in the State of Washington with specialized knowiedge of geote;h!ficaf/geologj;caA a'zgirl ing or a ge:,logist or e�-lgi� '�lg g o}rst:i sed ;le S-te of ya St`irs;,�=e.t,�.y_:L��''t? •r=_ sF os thc-ja�_ , .F; g 13hso cuer f Lhat gie-Gw_Aodi ica'° Report,diced J um- 2� 203, and entitled / r; �11,c Ineeis ail ire rX Ene argasors County resource Ordinande.Landslide Hazard Section, is=-iplefe and true,that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mi igated through the inciuded�cvicii�ru+al e72Si +e a'eCis ealce'naa ieS.anti mat ail Mils are alidgat6d i i sUQ*`i a Manner as to pravem' ±to rproparr:and jle?l'3 apd sna q ;c?t z. —d stamp" ,. �s�,,Yc7��'Ko /7U4r 6/W(3 'Plc�3t45�0 .vim Page 2 of 2 Form Effective June 2008 D!sC!a!n--ero Mason County dcas not ccftf_"the duality of the work done In this Onc;vtachnioa TABLE OF CONTENTS 1.0 INTRODUCTION..................................................................................................................................I 1.1 PROJECT INFORMATION.....................................................................................................................1 1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK.........................................................................1 2.0 SURFACE CONDITIONS....................................................................................................................3 2.1 GENERAL OBSERVATIONS..................................................................................................................3 2.2 TOPOGRAPHY......................................................................................................................................3 2.2.1 Upslope Geomorphology and Water Bodies...............................................................................3 2.3 SURFACE DRAINAGE...........................................................................................................................3 2.4 SLOPE AND EROSION OBSERVATIONS................................................................................................4 3.0 SUBSURFACE INVESTIGATION......................................................................................................5 3.1 FIELD METHODS,SAMPLING AND FIELD TESTING............................................................................5 3.2 GENERAL GEOLOGIC CONDITIONS....................................................................................................5 3.3.1 Groundwater...............................................................................................................................7 4.0 ENGINEERING ANALYSES AND CONCLUSIONS.......................................................................8 4.1 SLOPE STABILITY................................................................................................................................8 ALI Slope Stability Analysis...............................................................................................................9 4.1.2 Slope Stability Assessment........................................................................................................10 4.1.3 Septic Dralnfteld Impact to Critical Slopes..............................................................................10 4.2 EROSION............................................................................................................................................10 4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION.............................................................................11 4.3.1 Liquefaction..............................................................................................................................11 4.4 LATERAL EARTH PRESSURES...........................................................................................................11 4.5 ON-SITE AND OFF-SITE IMPACTS.....................................................................................................12 5.0 ENGINEERING RECOMMENDATIONS.......................................................................................13 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 Fxcavation.................................................................................................................................14 S.2.2 Placement and Compaction of Native.Soils and Engineered rill...........................................15 S.2.3 Retaining Wall Backftll............................................................................................................16 5.24 Wet Weather Considerations....................................................................................................16 5.2.5 Building Pads............................................................................................................................16 5.3 BUILDING AND FOOTING SETBACKS.................................................................................................17 5.4 SURFACE AND SUBSURFACE DRAINAGE...........................................................................................17 5.5 VEGETATION BUFFER AND CONSIDERATIONS.................................................................................17 5.6 TEMPORARY AND PERMANENT EROSION CONTROL.......................................................................18 6.0 CLOSURE............................................................................................................................................19 Appendix A-Site Plan Appendix B-Soil Information(Soil Profile;Soil Logs;Well Reports) Appendix C-Slope Stability Input&Output Appendix D—Erosion Control Appendix E—Drainage Details 1.0 INTRODUCTION Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a single family residential property located at 241 E Merrimount Rd, identified as parcel numbers 32236 75 00030 & 00040, Union, Mason County, Washington. See the vicinity map on the following page for a general depiction of the site location. The geotechnical investigation was conducted at the request of the property owner,Jeff Brittig, in support of the proposed development as detailed below. The proposed development, as provided herein,and the surrounding area is identified in this report as the Project. An initial geotechnical evaluation of the Project was conducted by Envirotech on June 6,2013. 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 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 Project was provided by the proponent of the property during the geotechnical investigation. Existing developments consists of a mobile home, on-site septic, driveways and cleared areas. The planned development consists of a pole building. Future development is expected to consist of a l- or 2-story single family residence, ancillary building, and other typical residential features.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: Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 1 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 • 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 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. 20 1 � 4 Project 28 I „s HOOD CANAL � — " �Es R3W € / l E HAWKS VIEW PI— I t 4 ~ 3 T21 NR3W p v. 1; T2�INR2W �,��M1son LAM -E MANZANITA OR --- Vicinity Map from Mason County Website Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 2 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 2.0 SURFACE CONDITIONS Information pertaining to the existing surface conditions for the Project was gathered on June 6, 2013 by Michael Staten, geotechnical engineer 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 The property is accessed from E Merrimount Road, an existing gravel roadway. The Project is currently undeveloped land. The access road extends onto the property from the west.Beyond the property, rural residential development exists. Vegetation on and near the Project consists primarily of secondary growth firs, cedars, alders, 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 inclinometer. See the Site Plan in Appendix A in this report for an illustration of general topography with respect to the planned development. A descending slope, with a maximum grade of approximately 24%, is located on the northwest side of E Merrimount road,which divides the project site. 2.2.1 Upslope Geomorphology and Water Bodies A critical ascending slope, with a grade exceeding 40%, is located to the southeast of E Merrimount road.The critical slope is variable up to about 50%with a total vertical relief between critical slope extents of at least 60 feet. The upslope area of the property is on a hillside, apparently created my ancient mass wasting deposits due to oversteepened gorges from glacial advances.Additional geomorphology that is pertinent to both upslope and downslope areas are provided in the Subsurface Investigation Section of this report. 23 Surface Drainage Stormwater runoff originating upslope from the anticipated development appears to primarily sheet flow away from or to the stream convergence. The stream is expected to be extreme during high intensity rainfall. Runoff originating upslope of the property is mostly diverted away from the developmental areas by accommodating topography. Stream overflow is not expected to influence the development.Other than stream scour,excessive erosion or other indications of past drainage problems were not observed within the immediate vicinity of the planned development. Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 3 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 June 24,2013 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. 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. �tltl ,o ,Ob HOOD CANAL • O� Jy �o Fy YJ h ,tl0 S� • Iao 1315 p0 f� Aerial Photo from Mason County Website Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 4 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the Project was primarily gathered on June 6, 2013 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 B 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 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 4.5 feet below the existing ground surface,and observing cut slopes/ shoreline banks of up to 10 feet within the vicinity of the property. Information on subsurface conditions also included reviewing geological maps representing the general vicinity of the project, and water well reports originating from nearby properties. Bulk samples were not collected at the Project site. 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 24 inches, and dense soils from 24 inches to the depth of terminous. 3.2 General Geologic Conditions In general, soils at the project are composed of materials from glacial advances. The geologic conditions as presented in the "Geologic Map of Washington," compiled by J. Eric Schuster, 2002 indicates Quaternary sediments, 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 Geologic Map of the Skokomish Valley and Union, 7.5-minute Quadrangles, Mason County,Washington by Michael Polenz,Jessica L.Czajkowski,Gabriel Legorreta Paulin, Trevor A.Contreras,Brendan A.Miller,Maria E.Martin,Timothy J.Walsh,Robert L.Logan, Robert J.Carson,Chris N.Johnson,Rian H. Skov, Shannon A.Mahan,and Cody R.Cohan,June 2010,this Project consists of Holocene to Pleistocene nonglacial deposits(Pre-Vashon till),and provides the following caption for this Project: Qmw Mass wasting deposits--Cobbles,pebbles,sand,silt,clay,boulders,and diamicton;generally unsorted,but locally stratified;loose;shown along potentially or demonstrably unstable slopes. Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 5 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 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 areas of borrowed fill. For engineering purposes, these native soils consist of distinguishable layers,as presented below. Soils within the upper 4.5 feet of natural ground were observed to be moist,brown silty sand with gravel(SM). Based on nearby well reports, site geology,and/or knowledge of the general area,soils below the upper 4.5 feet to an undetermined depth below the ground surface consist of layers of silty sand with gravel (SM) and gravel with silty sand (GM) with an occasional layer of silty clay. 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 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 Alderwood Gravelly Sandy Loam, Ac, with 15% - 30% slopes, and Alderwood Gravelly Sandy Loam, Ad, with 30% - 45% slopes.The soil designations are depicted in the aerial photograph below. ♦/ t 1► t 1 �r T22N R3W 36 .e t M � A j 35g. r Soil Survey From USDA Natural Resources Conservation Service Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 6 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax: 360-275-4789 June 24,2013 3.3.1 Groundwater From the water well report(s)and knowledge of the general area, permanent groundwater is at least 180 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. Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 7 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-2754789 June 24,2013 4.0 ENGINEERING ANALYSES AND CONCLUSIONS The following sections present engineering analyses and conclusions with relation to the existing conditions and proposed improvements of the Project. This section includes slope stability, erosion, seismic considerations, lateral earth pressures, 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, excessive and/or repeated surficial slope movements, if not repaired, may represent a threat to the structural integrity of the slope. If this situation does arise, the slope shall be inspected by a geotechnical engineer. Subsequently, maintenance may be required in order to prevent the possibility of further surficial or deep seated slope movements that may be damaging to life and property. According to the Coastal Zone Atlas of Mason County, Washington, the Project is within and near terrain labeled `Stable' and `Intermediate' regarding potential landslide activity. Stable slopes are generally not prone to landslides due to small grades and accommodating geology. Historically, intermediate terrains have no known landslides. However, this site is considered 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: z Project Map from Washington State Department of Ecology Website Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 8 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-2754789 June 24,2013 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. This delineation is primarily dependent upon slopes and convergence. Secondly, lithology and precipitation are modeled within this delineation. In summary, this designation is based on mapping without field observations or knowledge of the specific site geology or soils. A Resource Map from the DNR Forest Practices Application Review System is provided below: .5 Puget sou nd � 1 17C141 84 1704183 © JR Project � fir f��" • � �� . 1-041 .5 � �1fT�4188 Resource Map from Washington State Department of Natural Resources Website 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: 136 pcf Angle of internal friction: 32 degrees Cohesion: 0 psf Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 9 241 E Men imount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 Based on the slope stability analysis, a minimum factor of safety was determined to be 1.7 relative to static slope failures, and 1.1 with relation to seismic conditions. See the slope stability information in Appendix C for a depiction of input parameters and example of outputs. 4.1.2 Slope Stability Assessment DNR indicated previous landslide activity near the Project.Unstable slopes,as delineated by the Departments of Ecology and Natural Resources,are generally confined to the very steep slopes near the shoreline. Based on the results of the aforesaid slope stability analysis, and an evaluation of the surface conditions, it is our opinion that the proposed development should occur in accordance with this geotechnical report. 4.1.3 Septic Draintield Impact to Critical Slopes The approximate location of the existing septic drainfield is presented on the Site Plan in Appendix A of this report. Based on the septic drainfield location with relation to the existing and proposed topography,the drainfields are not expected to adversely influence the structures near the critical slopes. This is also based on compliance with all recommendations in this report. 4.2 Erosion Based on the USCS description of the Project soils, the surface soils are considered moderately 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 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). 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 contain specific erosion control options recommended for this Project. Additional erosion control measures than what is initially established may need to be employed if excessive erosion occurs during construction, or required by the prevailing agency. Complete erosion control information and specifications may be found in the latest addition of the "Stormwater Management Manual for Western Washington," prepared by the Washington State Department of Ecology Water Quality Program. Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 10 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 43 Seismic Considerations and Liquefaction Soils immediately below the expected foundation depth for this Project are generally Type D, corresponding to the International Building Code (IBC) soil profiles. According to the IBC, the regional seismic zone is 3 for this Project. The estimated peak ground acceleration ranges from 0.50g to 0.60g.This estimation is based on the United States Geological Survey(USGS)National Seismic Hazard Project in which there is an estimated 2% probability of exceedance within the next 50 years. There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this property is the Tacoma Fault Zone, in which is approximately 5 miles to the north of this Project. This information is based on the USGS Quaternary Fault and Fold Database for the United States. 43.1 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 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. An equivalent fluid unit weight used for structural design may be estimated as the product of the backfill soil unit weight and the earth pressure coefficient for at-rest pressures. Retaining walls should be designed to resist a lateral earth pressure based on an equivalent fluid unit weight of 45 pounds per cubic foot(pcf)and 55 pcf for backfill consisting of engineered fill and native soils, respectively. These values shall be increased by 1 pcf for every 1 degree of backfill/natural slope angle. These equivalent fluid unit weight values do not include lateral earth pressures induced by earthquakes or surcharges from live loads. See the Earthwork Construction Recommendations Section for details concerning the use of native soils,engineered fill and placement of backfill. Lateral earth pressure recommendations are based on active or at-rest earth pressures, and the backfill conforming to the recommendations outlined in the Earthwork Construction Recommendations Section of this report. For instances when it is necessary for the retained earth to induce passive earth pressures, additional design parameters must be accounted for in the retaining wall analysis. For these cases, recommendations should only be provided by a qualified engineer after the type of backfill is specified,and the final wall height is determined. Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 11 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-2754789 June 24,2013 I 4.5 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 Brittig Geotechnical Report PO Box 984 page 12 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-2754789 June 24,2013 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. 5.1 Building Foundation Recommendations Recommendations provided in this section account for the site development of a typical one- or two-story, single family residential structure, pole building, and ancillary 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. The soils on-site have low to moderate frost susceptible characteristics and should be used only to the extents provided in this report. 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. 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 18 inches below native ground beneath fill soils. These bearing capacity requirements also apply to isolated foundations, except the width should be increased to 24 inches for both round and square foundations. Poles for the pole building shall be placed at a depth of 48" into native soil Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 13 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 beneath existing fill. 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. 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. 5.13 Concrete Slabs-on-Grade Interior slabs, if utilized, should be supported on a minimum of 4 inches of compacted coarse, granular material (Passing U.S. Sieve #10 or greater) that is placed over undisturbed native subgrade or engineered fill.Native soils found at the Project site may be suitable for use as material directly beneath concrete slabs if it meets the aforesaid requirements or screened to meet these requirements. The top 2 to 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. 5.2 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. 5.2.1 Excavation Excavation is recommended to remove any excessive organic content, fill, or other deleterious material, if present, beneath foundations and to achieve appropriate foundation depth. Additional sub-excavation will be required for this Project if the soils below the required foundation depth are loose, saturated,or otherwise incompetent due to inappropriate land disturbing, or excessive water trapped within foundation excavations prior to foundation construction. All soils below the bottom of the excavation shall be competent, and relatively undisturbed or properly compacted fill. If these soils are disturbed or deemed incompetent, re-compaction of these soils below the anticipated Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 14 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 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. 5.2.2 Placement and Compaction of Native Soils and Engineered Fill For engineered fill or disturbed native soils that will be utilized as fill material directly beneath foundations, observation and/ or geotechnical testing is required prior to foundation construction. The following placement and compaction requirements are necessary. For disturbed native soils or engineered fill beneath foundations, limits of compacted or re-compacted fill shall extend laterally from the bottom edge of the foundation at a rate of one foot for each foot of compacted or re-compacted fill beneath the foundation. See the illustration below. FOOTING COMPACTED NATIVE SOILS OR ENGINEEREDFILL I � UNDISTURBED SUBGRADEI 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 native soils and engineered fill, respectively. Each lift should be uniformly compacted to at least 90% 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. Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 15 241 E Men imount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-2754789 June 24,2013 5.23 Retaining Wall Backfill Native soils may be used as retaining wall backfill for this Project if the recommendations below are followed. Backfill may also 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 to 24 inches. Each lift should be uniformly compacted to no more than 90% of the modified Proctor maximum dry density (ASTM D 1557). In addition, heavy construction equipment should be at a distance of at least % 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. Backfill for the retaining wall should extend vertically from the top of the footing to the proposed ground surface. The backfill should also extend horizontally from the back of the retaining wall to at least 2 feet. Perforated drain pipe for retaining walls should have a minimum diameter of 4 inches and direct water to an appropriate infiltration or outfall as recommended in the Surface and Subsurface Drainage Section of this report. Coarse, clean gravel(1 inch diameter)is recommended to be placed at least 24 inches around the drain pipe in order to provide increased drainage capabilities.Non-woven geotextile filter fabric designed to impede fine particles should be wrapped around the aforementioned coarse gravel for reducing the potential of silt migration and clogging of the drain pipe. 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 Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 16 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-2754789 June 24,2013 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 15 feet footing setback, for the ancillary building only, 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 15 FT MIN-� FOOTING Setbacks from the ascending slope is not required if vegetation is maintained on the slope,and all recommendations are followed in this report. 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. 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. Subsurface water intercepted in the footing perimeter drains, if any, and stormwater collected from roof drains shall be separately tight-lined to an appropriate infiltration location at least 10 feet downslope of the pole building. Subsurface infiltration is not required for contributing roof areas of 700 sf or less, and shall utilized an energy dissipater at the outlet. Recommended infiltration locations are delineated on the Site Plan in Appendix A, and drainage details are provided in Appendix E of this report. 5.5 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 Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 17 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 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 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, and may include stockpiling cleared vegetation, silt fencing, intercepting swales, berms, straw bales, plastic cover or other standard controls. Silt fencing is presented in this report as the first choice for temporary erosion control.Any erosion control should be located down-slope and beyond the limits of construction and clearing of vegetation where surface water is expected to flow. If the loss of sediments appears to be greater than expected, or erosion control measures are not functioning as needed, additional measures must be implemented immediately. See Appendix E for sketches and general notes regarding selected erosion control measures. The Site Map in Appendix A depicts the recommended locations for erosion control facilities to be installed. 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 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. Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 18 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 L 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. Therefore, it is recommended that a qualified engineer performs a site inspection during the earthwork construction if subsurface conditions found on-site are not as presented in this report. 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 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, Envirot h Engi eering !fb Michael Staten, P.E. Geotechnical Engineer Envirotech Engineering Brittig Geotechnical Report PO Box 984 page 19 241 E Merrimount Rd Belfair,Washington 98528 Parcel 32236-75-00030&00040 Ph. 360-275-9374 Mason County,Washington Fax:360-275-4789 June 24,2013 APPENDIX A SITE PLAN A SCALE, 1 INCH = 100 FEET 0 25 50 100 �pt1G N DRPXN% ++ Tpgo tNF�I +Y 0 60 / rai so 140 G 180 1 260 220 ry( 240 SETBACKS NOT REQUIRED FOR ASCENDING SLOPE 260 280 0 VEGETATION SHALL NOT BE 300 CLEARED ON SLOPES WITH GRADES GREATER THAN 40% EXCEPT AS PERMITTED BY 380 340 GEOTECHNICAL REPORT. 360 400 380 400 PROJECT/ OWNER/ LOCATION- SINGLE FAMILY RESIDENCE NOTES- GE❑TECHNICAL REP❑RT 1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. GENERAL LOCATIONS ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE BRITTIG GEOTECHNICAL REPORT. PARCEL 32236 75 00030 & 00040 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 PO BOX 984 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 Tplo TEST PIT SITE PLAN PROPERTY LINES. APPENDIX B SOIL INFORMATION VERTICAL AND HORIZONTAL SCALE. SCALE- I INCH 60 FEET 0 Af� ANCILLARY BLDG 12 FT CUT BANK MERRIMOUNT RD POLE BLDG \ FOUNDATION 16' INTO NATIVE GROUND OR RECOMPACTED FILL ILL FOUNDATION 4 FT 24t INTO NATIVE SOIL HOLOCENE NON-GLACIAL DEPOSITS (PRE-VASHON TILL) (SM 6 GM) SECTION A PROJECT/ OWNER/ LOCATION, SINGLE FAMILY RESIDENCE GE❑TECHNICAL REP❑RT BRITTIG PARCEL 32236 75 00030 8 00040 MASON COUNTY, WASHINGTON NOTES, ENGINEER, 1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENVIROTECH ENGINEERING POSITIVE DRAINAGE PO BOX 984 2) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF BELFAIR, WASHINGTON 98528 THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS. 360-275-9374 LOWER DEPTHS ARE BASED ON SITE GEOLOGY, WELL LOG(S), AND/OR EXPERIENCE IN THE GENERAL AREA. S❑IL PR❑FILE Map Unit Description:Alderwood gravelly sandy loam,30 to 45 percent slopes— Mason County,Washington Mason County, Washington Ad—Alderwood gravelly sandy loam, 30 to 45 percent slopes Map Unit Setting Elevation: 50 to 800 feet Mean annual precipitation:25 to 60 inches Mean annual air temperature:48 to 52 degrees F Frost-free period: 180 to 220 days Map Unit Composition Alderwood and similar soils: 100 percent Description of Alderwood Setting Landform: Drainageways Parent material: Basal till with a component of volcanic ash Properties and qualities Slope: 30 to 45 percent Depth to restrictive feature: 24 to 32 inches to densic material Drainage class: Moderately well drained Capacity of the most limiting layer to transmit water(Ksat).Very low to moderately low(0.00 to 0.06 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding: None Frequency of ponding. None Available water capacity: Low (about 3.4 inches) Interpretive groups Farmland classification: Not prime farmland Land capability(nonirrigated): 6e Hydrologic Soil Group: C Typical profile 0 to 10 inches: Gravelly ashy loam 10 to 28 inches:Very gravelly loam 28 to 60 inches: Gravelly sandy loam Data Source Information Soil Survey Area: Mason County, Washington Survey Area Data: Version 7, Jun 29, 2012 1 ',DA Natural Resources Web Soil Survey 6/17/2013 � Conservation Service National Cooperative Soil Survey Page 1 of 1 TEST PIT LOG TEST PIT NUMBER TP-2 PROJECT: SFR Geotechnical Report DATE OF LOG: 6/6/2013 PROJECT NO: 1349 LOGGED BY: MCS CLIENT: Brittig EXCAVATOR: N/A LOCATION: Parcel 32236 75 00030 & 00040 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 ILL PI CURVE AND TEST DATA DEPTH N 10 30 50 0 SM Brown, moist, loose to medium dense SILTY SAND with GRAVEL. Sand is medium. Gravel is course and 1 subrounded. Low plasticity. 2 3 4 Excavation terminated at approximately 4.0 feet 5 6 7 8 9 110 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this boring and should not be Geotechnical Engineering interpreted as being indicitive of the entire site. TEST PIT LOG TEST PIT NUMBER TP-1 PROJECT: SFR Geotechnical Report DATE OF LOG: 6/6/2013 PROJECT NO: 1349 LOGGED BY: MCS CLIENT: Brittig EXCAVATOR: N/A LOCATION: Parcel 32236 75 00030 & 00040 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 Fill 1 2 SM Brown, moist, loose to medium dense 3 SILTY SAND with GRAVEL. Sand is medium. Gravel is course and subrounded. Low plasticity- 4 5 Excavation terminated at approximately 4.5 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. a h WATER WELL REPORT CURRENT ZIP3y/Z Original&I"copy—Ecology,tad copy—owner,3i°copy—driller Notice of Intent No.WE 16025 DEPARTMENT OE dj ECOLOGY Construction/Decommission ("x"in circle) Unique Ecology Well ID Tag No.BHH 166 su.R a w.s1YARm, ® Construction Water Right Permit No. ❑ Decommission ORIGINAL INSTALLATION Property Owner Name Jeff Brittia Notice of Intent Number C PROPOSED USE: ® Domestic ❑ Industrial ❑ Municipal Well Street Address 241 E Merrimount ❑ DeWater ❑ Irrigation ❑ Test Well ❑ Other. City Union County Mason TYPE OF WORK: Owner's number of well(if more than one) ® New well ❑ Reconditioned Method:❑ Dug ❑ Bored ❑ Driven Location SWI/4-1/4 NWl/4 Sec 36 Twn 22N R 3W EWM ❑ +� ❑ Deepened ❑ Cable ® Rotary ❑ Jetted (s,t,r Still REQUIRED) or R DIMENSIONS: Diameter of well inches,drilledl99ft- wwM Depth of completed well 19911. CONSTRUCTION DETAILS Lat/Long Lat Deg 47" Lat Min/Sec 2121"N C Casing ® Welded 6' Diam.from +1 ft.to 194 ft. Long Dec,123' Long Min/See 0'48"W Installed: ❑ Liner installed Diam.from ft.to ft. Tax Parcel No.(Required) 322367500040 ❑ Threaded Diam.From ft.to It. Perforations: ❑ Yes ® No CONSTRUCTION OR DECOMMISSION PROCEDURE L Type of perforator used Formation:Describe by color,character,size of material and structure,and the kind and OSIZE of perfs_in.by in.and no.of perfs_from ft.to ft. nature of the material in each stratum penetrated,with at least one entry for each change 3 _ of information. (USE ADDITIONAL SHEETS IF NECESSARY.) _ Screens: 0 Yes ❑ No ® K-Pac Location 193 _ MATERIAL FROM TO Manufacturer's Name Alloy Machine Works Brown silty sand,pea gravel 0 19 Type Stainless Slotted Model No. Brown fine sand,pea gravel 19 25 Diam.5"slot size.018 from 194 fi.to 199 ft. Small to medium gravel coarse 25 Diam. Slot size ftom ft.to ft. brown sand,silt,wet 42 W Gravel/FLlterpacked: ❑ Yes ® No size of gravel/sand Brown siltbound sand 8r gravel 42 61 =..t Materials plead from ft.to ft. Brown fine silty sand,few 61 Surface Seal: ID Yes ❑ No To what depth?18ft. gravels 92 Material used in seal Bentonite Chios Brown fine sand,tight 92 94 LDid any strata contain unusable water? ❑ Yes ® No Small to medium multicolored 94 ~ Type of water? Depth of strata gravel,coarse brown sand wet 114 Method of sealing strata off Brown silty clay 114 1 117 Small to medium gravel,fine 117 PUMP: Manufacturer's Name 4 Type: H.P. brown sand,sift,tight 130 WATER LEVELS: Land surface elevation above mean sea level 122 ft. Multicolored gravel,medium 130 brown sand,loose 136 Static level 66ft.below top of well Date 004/24/2013 Brown fine sand 136 141 0 Artesian pressure lbs.per square inch Date Multicolored gravel,medium 141 Artesian water is controlled by (cap,valve,etc.) brown sand,loose 149 WELL TESTS: Drawdown is aroount water level is lowered below static level Gray sticky Gay 149 152 Sharp black gravel,fine gray 152 0 Was a pump test made? ❑ Yes ® No if yes,by whom? sand,silt,tight 157 Yield:_gal./min.with ft.drawdown after hrs. Yield: ral./min.with+_ft.drawdown after hrs. Multicolored gravel,medium 157 V Yield: ealJmin.with_ft.drawdown after hrs. brown sand,silt,loose 166 O Gray sticky day 166 167 Recovery data(lime taken ar zero when pump turned ojp(waver level measured jrom well top to water Ievell Multicolored gravel,medium 167 Time Water Level Time Water Level Time / brown sand,tight 179 all to medium multicolored 179 avel,medium brown sand I— water bearing 199 2Z Date of test 1^` Q]3 Brown fine sand,pea gravel 199 199 Bailer test 10 gal./min.with 18ft.drawdown after 1 hrs. YV A S[at� V v of Fcolo t:�, .l�.m a nt Airtest 3Qga1./min.with stem set at 1 Oft.for 1 hrs. d) Artesian flow p.m. Date 9y WR Date 4/23/2013 Completed Date 4/24/2013 Temperature of water 49*Was a chemical analysis made? ❑ Yes ® No 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 anj the information reported above are true to my best knowledge and belief. Driller En inea 0 Trainee (m ) osh 4p2p Drilling Company Arcadia Drilling Inc. Driller/En ineerrfrainee Si ature Address.Po Box 1790 Driller or trainee License No.2874 City,State,Zip Shelton Wa, 98584 IF TRAINEE:Driller's License No: Contractor's Drillers Signature: Registration No. ARCADD1098KI Date 4262013 EC Y 050-1-20(Rev 02/10) If you need this document in an alternate formal,please call the►tinter Resources Program at 360-407-6872. Persons with hearing loss can call 711 for Washington Relay Service. Persons with a speech disability can call 877-833-6341. APPENDIX C SLOPE STABILITY STABLE Slope Stability Analysis System New User Project Brittig Datafile: Dynamic Bishop STABLE Version 9.03.00u Bishop TITLE Dynamic UNITS (Metric/Imperial) = I GEOMETRY DEFINITION POINTS NO. X Y 1 0.000 0.000 2 50.000 0.000 3 790.000 -260.000 4 840.000 -264.000 5 84.000 -11.950 6 119.370 -24.370 7 154.740 -36.800 8 190.110 -49.230 9 225.470 -61.650 10 260.840 -74.080 11 296.210 -86.510 12 331.580 -98.930 13 366.950 -111.360 14 402.320 -123.790 15 437.680 -136.210 16 473.050 -148.640 17 508.420 -161.070 18 543.790 -173.490 19 579.160 -185.920 20 614.530 -198.350 21 649.890 -210.770 22 685.260 -223.200 23 720.630 -235.630 24 756.000 -248.050 LINES Lo X Hi X SOIL 1 2 1 2 3 1 3 4 1 SOILS SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT. 1 Soil—1 CONTINUOUS-BLACK 0.00 32.0 136.000 PORE PRESSURE SPECIFICATION STABLE Slope Stability Analysis System New User Project Brittig Datafile: Dynamic Bishop SOIL PIEZO RU EXCESS Y/N/P Value Value 1 N 0.000 0.000 PIEZOMETRIC SURFACE POINT POINT PORE PRESSURES POINT PRESSURE SLIP DIRECTION (+/- X) _ + SLIP-CIRCLES AUTOMATIC Circle Centre Grid Extremities 672.000 * * 84.000 * * 756.000 * * *************** 0.000 X spacing -- no. of cols (max 10)= 10 Y spacing -- no. of rows (max 20)= 20 Grid 1 Circles through point 5 Grid 2 Circles through point 6 Grid 3 Circles through point 7 Grid 4 Circles through point 8 Grid 5 Circles through point 9 Grid 6 Circles through point 10 Grid 7 Circles through point 11 Grid 8 Circles through point 12 Grid 9 Circles through point 13 Grid 10 Circles through point 14 Grid 11 Circles through point 15 Grid 12 Circles through point 16 Grid 13 Circles through point 17 Grid 14 Circles through point 18 Grid 15 Circles through point 19 Grid 16 Circles through point 20 Grid 17 Circles through point 21 Grid 18 Circles through point 22 Grid 19 Circles through point 23 i i 1 . O OC tG S TF.B�E.2002 ^�Z �.�scclata Lto I CD CD I 1 . 2C 1 . 3C i. ` 1 . 4C 1 . 6 C i � I I L�dtdflP _ tlC Analysis bishop STABLE.2002 MZ Associates Ltd it APPENDIX D EROSION CONTROL GE❑TEXTILE 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' 1 WASHED GRAVEL OR VEGETAT N 2.5 FT DIRECTION OF EXISTING WATER FLOW GROUND SURFACE l2' 2.5 FT 8' t- SILT FENCE - CROSS SECTION N.T.S. 2'x2' WOOD POST (TYP) GEOTEXTILE FABRIC OR EQUIVALENT OR BETTER AND WIRE MESH @ 6 FT MAX, O.C. 6 FT - � 0.5 FT EXISTING GROUND SURFACE z r 12' DEEP, 8' WIDE } TRENCH FILLED WITH I FT 3/4' TO 1 1/2' 2.5 FT WASHED GRAVEL OR VEGE TI BOTTOM EXTENTS OF GE❑TEXTILE FABRIC SILT FENCE - DETAIL N.T.S. PR❑VIDE FULL WIDTH 3/4 IN TO 1 1/ I F INGRESS/EGRESS CRUSHED GRAVEL1 � Fr PLACED AT 6 IN MINIMUM DEPTH WELL-DRAINED SOILS -0,02 IN/MIN FULL LENGTH R=25 FT MIN (i- PROJECT/ OWNER/ LOCATION, ACCESS ROAD SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT STABILIZED CONSTRUCTION ENTRANCE BRITTIG N.T.S. PARCEL 32236 75 00030 & 00040 MASON COUNTY, WASHINGTON ENGINEER, ENVIROTECH ENGINEERING PO BOX 984 BELFAIR, WASHINGTON 98528 360-275-9374 EROSION CONTROL P. 1 PERMANENT EROSION CONTROL NOTES; ENERAL NOTES- SEEDING FOR RAW SLOPES 1. SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON THESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL HALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES, . ALL EROSION AND SEDIMENT CONTROL 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, 3. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS ACCROS LACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED, OR PERPENDICULAR TO THE SLOPE. 3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE EMPORARY EROSION CONTROL NOTES, APPLIED AT THE RATE OF 120 POUNDS PER ACRE. 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL ❑R ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A FOSTER AND PROTECT THE ROOT STRUCTURE, ERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE 5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30, MMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED ARMORING OF THE SEED BED WILL BE NECESSARY, (e.g., ROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING). LONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF 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. R OTHER APPROVED TREATMENT. USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION RY SEASON (MAY I THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE. EMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO NLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE PROPORTIONS PURITY GERMINATIO THERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED NAME BY WEIGHT<X) <%) (%) Y NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE TABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL REDTOP (AGROSTIS ALBA) 10 92 90 REAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90 HROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, CHEWING FESUE 40 97 80 REE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED (FESTUCA RUBRA COMMUTATA) LAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, (JAMESTOWN, BANNER, SHADOW, KOKET) ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE WHITE DUTCH CLOVER 10 96 90 ERFORMED DURING THE FOLLOWING PERIODS- MARCH I TO MAY 15, AND AUGUST 15 TO (TRIFOLIUM REPENS) CTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION F THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE MULCHING O SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT OSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, 1, MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD LASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000 EPTEMBER 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 (HORIZONTAL-VERTICAL). CTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE 3. MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN WNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON, ALL ND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1. EAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR HE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. TOPSOILING ET SEASON (OCTOBER 1 THRU APRIL 30) -- ON SITES WHERE UNINTERUPTED 1, TOPSOIL SHOULD BE USED FOR THIS PROJECT DUE TO HIGHLY ONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE DENSE EXPOSED SOILS. REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED 2, TOPSOIL SHOULD BE PLACED ON SLOPES NOT EXCEEDING 2,1. TO AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN 3. STRIPPING AND STOCKPILING ON-SITE SOILS SHALL ONLY BE HE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT PERMITTED IF TOPSOIL IS FRIABLE AND LOAMY (LOAM, SANDY LOAM, TRANSPORT OFF-SITE IS OBSERVED. SILT LOAM, SANDY CLAY LOAM, CLAY LOAM). LL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE 4. STRIPPING SHALL BE CONFINED TO THE IMMEDIATE CONSTRUCTION AREAS OVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC . A FOUR T❑ SIX INCH STRIPPING DEPTH IS COMMON, BUT MEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER DEPTH MAY VARY DEPENDING ON THE PARTICULAR SOIL. ALL SURFACE RUNOFF CONTROL STRUCTURES SHALL BE IN PLACE BEFORE AVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED. 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 EING 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. STOCKPILE MANAGEMENT 1. STOCKPILE SHALL BE STABILIZED (WITH PLASTIC COVERING OR OTHER APPROVED DEVICE) DAILY BETWEEN NOVEMBER I AND MARCH 31. 2. IN ANY SEASON, SEDIMENT LEACHING FROM STOCK PILES MUST BE PREVENTED. 3. TOPSOIL SHALL NOT BE PLACED WHILE IN A FROZEN OR MUDDY CONDITION, WHEN THE SUBGRADE IS EXCESSIVELY WET, OR WHEN CONDITIONS EXIST THAT MAY OTHERWISE BE DETRIMENTAL TO PROPER GRADING OR PROPOSED SODDING OR SEEDING. 4. PREVIOUSLY ESTABLISHED GRADES ON THE AREAS TO BE TOPSOILED SHALL BE MAINTAINED ACCORDING TO THE APPROVED PLANS. STABILIZED CONSTRUCTION ENTRANCE 1. MATERIAL SHALL BE 4 INCH TO 8 INCH QUARRY SPALLS (4 TO 6 INCH FOR RESIDENTIAL SINGLE FAMILY LOTS) AND MAY BE TOP-DRESSED WITH 1 INCH TO 3 INCH ROCK. (STATE STANDARD SPECIFICATIONS, SECTION 8-15.) 2. THE ROCK PAD SHALL BE AT LEAST 12 INCHES THICK AND 50 FEET LONG (20 FEET FOR SITES WITH LESS THAN 1 ACRE OF DISTURBED SOIL). 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 DONE ON AN AREA COVERED WITH CRUSHED ROCK AND WASH WATER SHALL DRAIN TO A SEDIMENT RETENTION FACILITY OR THROUGH A SILT FENCE. SILT FENCE PROJECT/ OWNER/ LOCATION, 1. 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 2. GEOTEXTILE FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO THE LENGTH OF GE❑TECHNICAL REPORT EACH BARRIER TO AVOID USE OF JOINTS. IF JOINTS ARE NECESSARY, FILTER FABRIC SHALL BE SPLICED BRITTIG TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT PARCEL 32236 75 00030 & 00040 BOTH ENDS TO THE POST. MASON COUNTY, WASHINGTON 3, STANDARD FILTER FABRIC SHALL BE FASTENED USING 1' STAPLES OR TIE WIRES (HOG RINGS) e 4 IN PACING. 4. POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEER- RIVEN SECURELY INTO THE GROUND. ENVIROTECH ENGINEERING . WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVILENT. THE WIRE MESH MAY BE ELIMINATED IF P❑ BOX 984 XTRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED. BELFAIR, WASHINGTON 98528 5. A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE OF THE 360-275-9374 OSTS AND UPSLOPE FROM THE SILT FENCE. 7. SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. EROSION CONTROL P. 2 APPENDIX E DRAINAGE DETAILS HOUSE ROOF DOWNSPOUT SERVES UP TO 700 SF OF ROOF FOR ROOF DOWNSPOUT SERVING 700 SF OF ROOF OR LESS 50 FT MIN VEGETATED FLOW PATH DOWNSPOUT EXTENSION ROOF DOWNSPOUT AND SPLASH BLOCK DETAILS N.T.S. FINAL GROUND SURFACE GEOTEXTILE FABRIC WRAPPED AROUND QUARRY SPALL CORRUGATED TIGHTLINE 8-12 INCH QUARRY SPALL OR 6-INCH MIN. DIAMETER APPROVED INFILTRATION MEDIA 0 OOOOOOOOOOO 000000000000 1 FT MIN 0000000000000 SUBSURFACE DRAINAGE DETAILS NOTE- N.T.S. INFILTRATION FACILITY COMPONENTS AND SIZE MAY NEED TO BE DETERMINED BY A DRAINAGE ENGINEER AND/ OR PREVAILING GOVERNMENT AGENCY. PROJECT/ OWNER/ LOCATION, SINGLE FAMILY RESIDENT GEOTECHNICAL REPORT BRITTIG PARCEL 32236 75 00030 & 00040 MASON COUNTY, WASHINGTON ENGINEER- ENVIROTECH ENGINEERING PO BOX 984 BELFAIR, WASHINGTON 98528 360-275-9374 DRAINAGE DETAILS 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: 'rr�� Permit# 6rrv`� 1�� J `V 54arcel# 371,V✓v I� �0030 Date(s) of Docu ent(�revie©d: (1) (a)A discu ion of general geologic conditions in the vicinity of the proposed development, OK? Comment: (b) A disc ssion of specific soil types OK?V Comment: (c) A di�sVssion of ground water conditions OK? V Comment: (d) A is ssion of the upslope geomorphology OK? Comment: (e) Adis ssion 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 refergnced maps and records OK? Comment: 1r, �& (2) A site plany�'hich identifies the i port nt de v opment and geologic features. OK? l/ Comment: 1 (3) Locations 94d logs of exploratory hole probes OK? V Comment: (4) The area of the proposed development, thi boundaries of the hazard, and associated buffers and setbacks sh yA be delineated (t p, th Sid and toe)on a geologic map of the site. OK? V Comment: (5) A myinporates f one cross section at a ale which adequately depicts the subsurface profile, and Which the details of prop a gracW changes. OK. Comment: Z7 (6) A description and results of slope stabilify Analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic s ety factor is 1.1. and the qua�i:.st ti analysis coeffients should be a value of 0.15. OK? Comment: ''l (7) (a)Appro late restrictions on placement clArainage features OK? Comment: (b) Approp ate restrictions on placement of septic drain fields OK?Comment: (c) Appropr to 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 ' C OK? Comment: 117 (e) Recom nded setbacks from the lands ide hazard areas shoreline bluffs and the tops of others pes on the property. OK? Comment: C7 (8) Recommendations for the preparati n 8f a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method ofy6getation removal. OK? V Comment: (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies specific mitigating measures to be implemented during construction to protect the slope fro erosion, landslides and harmful construction methods. OK? Comment: (10) An analysi f 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: I� (13) A site map d wn to scale showing the pro erty boundaries, scale, north arrow, and the location and natur f existing and propose d elop on the site. OK? Comment: tA w l� Are the Documents signed and stamped? Type and #of License: If not approved, what is the next action/recommendation for further action? C ��3 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 aui3ertirEai �r�eciciist s-or a Geo%ecnnicai repo,z Instructions: This checklist must be submitted with a Geotechnical Report and completed,signed,and stamped by the licensed professional(s)who prepared the GeotechnicalReport for review by Mason County pursuant to the =:;ason County F wsource Jrdii3ance_ ff an Bern found to be not applicable,the report should ex-plain the basis for the conclusion Applicant/Owner (I Parcel# 3 223� 7� 0 Site Address 2 koaa� Vf/,Ord (1) (a)A discussion of general edlogic conditions in the vicinity of the proposed developrilent, Located on page(s) 17 (b) A discussiO ,ar Specl�C sort Types Located on page(s) (c) A discussion of ground water conditions Located an page(s) 7 (d) A discussion of the u lope geomorphology Located on page(s) .5 (e) A discussion of the location of upland waterbodies and wetlands ocated on pages) 3 j A discussion uf hisiory or iandsiide activity in the activity in the vicinity,as available in the referenced maps and records Lcca'cd on pages? g, y (2) A site plan which identifies the im orient devela ment and geologic features. Located on Maps) SFr a t �c� e,/�� (3) Locations and logs of exploratory h tes or probes_ L i ( )_1/_.^-_p� GG '.Itii']LCu3 till iVic`1 'J 7. U "J' I L�Jt�) (4) The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineate)(top,, both sides,and toe)on a geologic map of the site. Located o�i [Wap(s) (5) A minimurn of one cross section at a scale which adequately depicts the subsurface profile,and which incorporates the details of pr .. ose grade changes. Z_OcaLGu VH fvl;a 7(.�.'.) ✓Co; /�T`�� G , 13 � - (6) A description and results of store stability analyses pefformed fbr both static and seismic io_B&hg conditions_Analysis should examine worst case failures_The analysis should include the :;:Yiifi d i�.iSito}'r,="�iaeraoL�t2i Ug-cle4_The minird mn static safety factor is$_5,the rrikfturn seismic safefv factor is 1_1_ and the quasi-static analysis dents should be a`Jalue of 0-15_ Located on page(s) (7) (a)Appropriate restrictions on plac-e€nent of drainage features Lacaied on page(s) 17 .00) Appropriate r est,tenons on placernent of septic drain fields Located on page(s) /D 'Cl Appropriate restrictions on placement of compacted tills and footings Located on page(s) Page I of 2 Form Effective June 2008 Disclain—jer: Mason County does not certify the quality of the work done in this 3eotc f«^.;,;!I'.ep„d. (d) Recommended buffers from the landslide hazard areas shoreline'bluffs and the tops of other slopes on ire property_ Located on page(s) /7 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property- Located on page(s) 1 (8) Recommendations for the preparation of a detailed clearing and grading plan wi liGh specicically identities vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. Located on page(s) r`7 (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 (-iO) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) / '2- -- (i i) Specifications of final development conditions such as, vegetative management,drainage, erosion control,and buffer widths. Located on page(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 sole showing the property boundaries.scale.-north arrow, and the location and nature of existing and pro,pposed development on the site. died on€;►'rap(s) tvwl GI y d,, S hereby carW under penalty of PIE rjury irhat i am a cmi engineer licensed in the State of Waaftiton with specialized knowiedge of geotecli_nicaJgealogmai ai-Wawing or a geologist or engiise g moist IL-Wised in the State Of ij 7�� le`_+.!r,,;!_: -�: 3sS•� '!q_�:;:v O5 ". z= � _-:..*.St�S.12i�,,!ee that 9'=-G o"c -iTIG2'- Deport, dated U%� Z 2-2f 3, and entitled mks SH the reqwremenis of the Mason County Resource O . ante.Landslide Hazard Section,is compWa and true.ghat the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geoiec.nicai design reco u-ner•.da-zons,ana:that ag hazm-dS am anftatad ire such a manner as to pr?�►er±z �_ ; • Q�ps�r s��,: ? heait€a ar: sue_( and Ste tp; P 1 CLYD_ 4_ '4--33o�k3 �r�V AL Page 2 of 2 Form Effective June 2008 D€sc!a€r.:er: Masan county eves not certify";a:quality of the work done In this usotacynicaf Rapp t.