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Home My WebLink AboutGEO2021-00040 - BLD Engineering / Geo-tech Reports - 4/14/2021 Gte2zzi _000 yd REcEi VED APR 14 20?1 615 W A4?cf,,,,.v�tTa�t MASON COUNTY Submittal Checklist COMMUNITY SERVICES Geotechnical Report Instructions: PLANNING This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item is found not applicable,the report should explain the basis for the conclusion. Note: Unless specifically documented, this report does not provide compliance to the International Residential Code Sections R403.1.7 for foundations on or adjacent to slopes, Section R403.1.8 for expansive soils or section 1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes. Applicant/Owner Sena Smith Parcel# 12220-33-00250 Site Address XXX Russet Ridge Road, Allyn (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 5 (b) A discussion of specific soil types, Located on page(s) 6 (c) A discussion of ground water conditions, Located on page(s) 6 (d) A discussion of the upslope geomorphology, Located on page(s) 3 (e) A discussion of the location of upland waterbodies and wetlands, Located on page(s) 3 (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) 11 (2) A site plan which identifies the important development and geologic features. Located on Map(s) Site Plan—Appendix A (3) Locations and logs of exploratory holes or probes. Located on Map(s) Site Plan and Soil Logs(Appendix Q (4) The area of the proposed development,the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides, and toe)on a geologic map of the site. Located on Map(s) Geologic Map—Appendix B (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile,and which incorporates the details of proposed grade changes. Located on Map(s) Soil Profile(Appendix C1 (6) A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures.The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic safety factor is 1.1,and the quasi-static analysis coefficients should be a value of 0.15. Located on page(s) 12 Page 1 of 3 (7) (a) Appropriate restrictions on placement of drainage features, Located on page(s) 17 (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) 16 (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) 8 and 10 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 17 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 16 (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. Located on page(s) 16 (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) 16 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 18 (11) Specifications of final development conditions such as,vegetative management,drainage,erosion control, and buffer widths. Located on page(s) 16- 18 (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) n/a—see report (13) A site map drawn to scale showing the property boundaries,scale, north arrow,and the location and nature of existing and proposed development on the site. Located on Map(s) Site Plan I, Michael Staten, hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical PEti CLYDe ST Report,dated June 12,2008,and entitled Knudsen Tracts �Nc`2'1 of AS IA, Single Family Residences, meets all the requirements of the a Mason County Resource Ordinance, Geologically Hazardous Areas Section, is complete and true,that the assessment p�43045 , v demonstrates conclusively that the risks posed by the landslide /STER �SS�OISTr_ `T hazard can be mitigated through the included geotechnical 3/26/21 design recommendations, and that all hazards are mitigated in Disclaimer: Mason County does not such a manner as to prevent harm to property and public certify the quality of the work done in health and safety. this Geotechnical Report. Page 2 of 2 EvI'v%Wotec'k Ev�,O�weer-w'g ceoteohvUo6IL o EvwlrovtmevttoL°praLwage ° �adwa� March 23,2021 Jack Johnson Construction,Inc. PO Box 1119 Belfair,Washington 98528 Sena Smith 300 E Archer Ridge Road Allyn,Washington 98524 RE: Geotechnical Report Addendum#1 for Knutsen Tracts Single Family Residences,Parcel 12220-33-00250,Mason County,Washington Dear Mr.Johnson, Envirotech Engineering (Envirotech) has completed this geotechnical report addendum for the above referenced project. The original report, dated June 12, 2008, was prepared by Envirotech (Project#0857). The project site was revisited by Michael Staten with Envirotech on multiple occasions during the preparation of the original report, subsequent addendum, and inspections. A recent site visit was performed on March 15, 2021 to evaluate the proposed project and verify the absence of new geotechnical hazards since our initial site visit in 2008. We conclude that the natural topographic and geologic conditions were virtually unchanged with relation to the safety of the property. The subject parcel is known as Lot 9 of the Knudsen Tracts within our original report. It is our opinion that the all geotechnical parameters are per current code, and that the development may commence per the original report. Envirotech is pleased to submit this addendum. Please contact Michael Staten at 360-275-9374 if you have any questions,comments,or require additional information. Best Regards, Envirotech En ineenng PTV CLYDE rr cL1+�pQ V1Asy I 43045. RAC, S f, SS10 'At,ENG 3/23/21 Michael Staten,P.E. Geotechnical Engineer Envirotech Engineering Geotechnical Report Addendum#1 PO Box 984 Page 1 of 1 Knudsen Tracts Single Family Residences Belfair,Washington 98528 Parcel 12220-33-00250 Ph. 360-275-9374 March 23,2021 Geotechnical Report for Knudsen Tracts Single Family Residences East Sherwood Creek Road Parcels 12220 33 00210, 12229 22 00320, 12220 33 90221, 12220 33 90222, 12220 33 90223 & 12220 33 90224 Mason County, Washington June 12, 2008 Project #0857 Prepared For: Jack Johnson Construction, Inc. PO Box 1119 Belfair, Washington 98528 Prepared By: Envirotech Engineering PO Box 984 Belfair, Washington 98528 Phone: 360-275-9374 PTV CLYDE S� 43045 cv� 0F FC1S'fE�F" �'SSONALbNG` 6/12/08 TABLE OF CONTENTS 1.0 INTRODUCTION................................................................................................................................. 1 1.1 PROJECT INFORMATION.................................................................................................................... 1 1.2 PURPOSE OF INVESTIGATION............................................................................................................. 1 1.3 SCOPE OF WORK................................................................................................................................ 1 2.0 SURFACE CONDITIONS....................................................................................................................3 2.1 GENERAL OBSERVATIONS..................................................................................................................3 2.2 TOPOGRAPHY.....................................................................................................................................3 2.2.1 Upslope Geomorphology............................................................................................................3 2.2.2 Downslope Geomorphology....................................................................................................... 3 2.3 SURFACE DRAINAGE..........................................................................................................................3 2.4 SLOPE AND EROSION OBSERVATIONS...............................................................................................4 3.0 SUBSURFACE INVESTIGATION.....................................................................................................5 3.1 FIELD METHODS,SAMPLING AND FIELD TESTING...........................................................................5 3.2 GENERAL GEOLOGIC CONDITIONS...................................................................................................5 3.3 SPECIFIC SUBSURFACE CONDITIONS.................................................................................................6 3.3.1 Groundwater............................................................................................................................... 6 3.4 Sows TESTING...................................................................................................................................6 4.0 ENGINEERING ANALYSIS,CONCLUSIONS AND RECOMMENDATIONS...........................8 4.1 BUILDING FOUNDATION RECOMMENDATIONS..................................................................................8 4.1.1 Bearing Capacity........................................................................................................................ 8 4.1.2 Settlement................................................................................................................................... 8 4.1.3 Concrete Slabs-on-Grade........................................................................................................... 9 4.2 LATERAL EARTH PRESSURES............................................................................................................9 4.3 EARTHWORK CONSTRUCTION RECOMMENDATIONS........................................................................9 4.3.1 Excavation.................................................................................................................................10 4.3.2 Placement and Compaction of Native Soils and Engineered Fill...........................................10 4.3.3 Retaining Wall Backfill.............................................................................................................11 4.3.4 Wet Weather Considerations....................................................................................................11 4.3.5 Building Pads............................................................................................................................11 4.4 SLOPE STABILITY AND EROSION CONTROL.....................................................................................11 4.4.1 Septic Drainfield Impacts.........................................................................................................16 4.4.2 Building and Footing Setbacks.................................................................................................16 4.4.3 Temporary and Permanent Erosion Control...........................................................................16 4.4.4 Surface and Subsurface Drainage...........................................................................................17 4.4.5 Vegetation Considerations........................................................................................................17 4.4.6 Off-site impacts.........................................................................................................................18 4.5 SEISMIC CONSIDERATIONS AND LIQUEFACTION..............................................................................18 5.0 CLOSURE.............................................................................................................................................19 Appendix A-Site Plan Appendix B—Geological Map Appendix C-Soil Information Appendix D-Slope Stability Appendix E—Erosion Control Appendix F—Drainage Details 1.0 INTRODUCTION Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a future nine lot subdivision on parcel numbers 12220 33 00210, 12229 22 00320, 12220 33 90221, 12220 33 90222, 12220 33 90223, and 12220 33 90224, Mason County, Washington (Project). As presented herein, this report includes information pertaining to the Project in this Introduction Section; observations of the property and surrounding terrain in the Surface Conditions Section; field methods and soil descriptions in the Subsurface Investigation Section; and, recommendations for foundation, settlement, earthwork construction, lateral earth pressures, slope stability, erosion control, drainage and vegetation considerations in the Engineering Analysis and Recommendations Section. An initial geotechnical evaluation of the Project was conducted by Envirotech with the property owner,Jack Johnson, on May 9, 2008. It was previously determined that slopes in excess of 40% with a vertical relief of at least 10 feet were present within 300 feet of the planned development. Consequently,the proposed development will require a geotechnical report pursuant to Landslide Hazard Areas of Mason County Resource Ordinance 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. 1.1 Project Information Information pertaining to the Project was provided by the property owner and owner's representative with general assumptions by Envirotech that are typical of this type of development. The Project is accessed from an unimproved road linking Sherwood Creek Road. See the vicinity map on the following page of this report for a general location of the site. The property is currently vacant land with a dirt road accessing all the planned lots, and one well head. The planned development consists of 1- or 2-story single family residences on each lot. Foundation construction is expected to consist of continuous strip footings and concrete slab-on- grade or stem walls. Anticipated construction other than the residence will include driveways, stormwater management systems, and possible ancillary features typical of this type of development. Septic drainfields are not anticipated for this Project. Earth movement consisting of cutting high areas and filling the low portion of undulations is expected. Approximate building footprint with relation to site features are illustrated in the Site Map in Appendix A. 1.2 Purpose of Investigation The purpose of this geotechnical investigation was to evaluate the Project in order to provide geotechnical recommendations relating to the development of the property. The investigation included characterizing the general Project surface and subsurface conditions, and evaluating the suitability of the soils to support the planned site activities. 1.3 Scope of Work In order to fulfill the purpose of investigation, the geotechnical program completed for the proposed improvements of the Project include: • Review project information provided by the Project owner and/ or owner's Envirotech Engineering Geotechnical Investigation PO Box 984 page 1 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 representative. This included a grading and stormwater management plan completed by Michael Wnek,P.E.; • Conduct a site visit to document the site conditions that may influence the construction and performance of the proposed improvements; • Define the general subsurface conditions of the site by observing subsoils extending to a depth of up to 35 feet below the natural ground surface, 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 properties of the soils that include 8 visual classifications,2 in-place density tests,and one direct shear test; • 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. W } 14 1�3/' � 3 3 �sao c� = W caa�c,k. P v t � E LN 23 Oft 19 n 20 �RJcbttlab V 26 30 - f {r /4Y AWPoodAp �Cs;ffls,huAv Project E ERMERREI DR ® 87 36 31 32 33 Vicinity Map from Mason County Website Envirotech Engineering Geotechnical Investigation PO Box 984 page 2 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 2.0 SURFACE CONDITIONS Information pertaining to the existing surface conditions for the Project was gathered on May 9, May 16,and May 24, 2008 by Michael Staten, geotechnical engineer with Envirotech. During the site visits,the type of geotechnical investigation was assessed, site features were documented that may influence construction and slope stability, soil samples were collected from selected locations, and near-surface soils were visually classified. This Surface Conditions Section provides information on general observations, vegetation, topography, drainage and slope/ erosion conditions for the Project and surrounding areas that may impact the Project. 2.1 General Observations The Project is currently vacant land as previously mentioned. Sherwood Creek Road borders the southeast portion of the property, and a residential subdivision is located to the north and west of the property. Beyond the property lines, exist low to moderate density residential development. Vegetation on and near the Project consists primarily of firs, alders, maples,blackberry, and other trees and shrubbery common to this area of the Pacific Northwest. Past clearing has been completed for this property. An aerial photo of the project and immediate vicinity is provided on the following page. 2.2 Topography The Project is situated within and near moderate to very steep sloping terrain. The topographic information provided in this section was extrapolated from a public lidar source,and incorporated observations and field measurements. Slope verification included measuring slope lengths and inclinations with a cloth tape and clinometer. See the Site Map in Appendix A and the Geological Map in Appendix B in this report for an illustration of general topography with respect to the planned development. 2.2.1 Upslope Geomorphology Ascending grades are located to the north and west of the planned development. These slopes are extremely variable, with undulations and vertical reliefs ranging from 10 to 40 feet from the property line. There are no apparent water bodies or wetlands located upslope from the planned development. 2.2.2 Downslope Geomorphology Descending grades also vary considerably, and are limited to a vertical relief of no more than 130 feet of slopes exceeding 40%. Some isolated areas with vertical reliefs of less than 25 feet were observed to have slopes greater than 100%. See the Site Plan and Geologic Map in the appendices of this report. 2.3 Surface Drainage Stormwater runoff originating upslope from the anticipated development is expected to be minimal. Sheet flow down the sloping grades towards the planned development is expected. Most of the upslope runoff appears to be diverted away from the property due to the upslope Envirotech Engineering Geotechnical Investigation PO Box 984 page 3 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 development. Sheet flow down the steeper slopes can be expected, with some minor convergences. Excessive scour, erosion or other indications of past drainage problems were not observed at or near the planned development. It is apparent that the upslope development manages most of its stormwater,and distributes runoff without impacting the Project. 2.4 Slope and Erosion Observations The existing steep slopes 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 or naturally 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. Significant mass wasting on the property was observed. Indications of recent and past landslides were apparent on the very steep descending slopes. The landslides were limited to shallow translational failures extending to depths of almost 2 feet.The slides did not exceed a length of 30 feet at the bottom failure surface, and had widths of less than 15 feet. Indications of deep seated slope problems ere not apparent-,or observed du rin the site visit. 77V?-- F�akFSyoR� j,��' C� R � QLS�TR��'` � },+� }`'�.� �•�7�� r f. ESHERW ^'��V • CREEK RD ej k7 E NORTH BAY PL .��; t� `. .� is .tl .•`fir( ,,j ° i� �� j 'p'. .a t Aerial Photo from Mason County Website Envirotech Engineering Geotechnical Investigation PO Box 984 page 4 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the Project was gathered on May 16, and May 24, 2008 by Michael Staten,geotechnical engineer with Envirotech. Specific information on field methods, sampling, field testing, subsurface conditions, and results from soil testing are presented in this section of the report. Appendix C of this report includes pertinent information on subsurface conditions for the Project, such as subsoil cross-sections, test pit log(s) representative of the bearing soils of the planned building, and water well report(s). Applicable test pit and well log locations are depicted on the Site Plan and Geologic Map provided in the appendix of this report. 3.1 Field Methods,Sampling and Field Testing Information on subsurface conditions for the Project was accomplished by examining soils within test pits extending to depths of up to 15 feet below the existing ground surface, observing soils within existing cuts on the slope of up to approximately 35 feet below the natural ground surface, and observing soils within the shallow landslides. Information on subsurface conditions also included reviewing geological maps and water well reports originating from nearby properties. Bulk samples were collected at the Project site ranging from approximately 2 feet to 15 feet below the existing ground surface. A bulk sample was transported to PSI laboratory for direct shear testing. An additional sample was obtained by driving brass rings into the sandy clay soils exposed at the landslide. The soil samples collected were secured and transported for laboratory testing. From a sand cone test,Envirotech measured the relative density of the upper soils,at a depth of 1- foot below the existing grade. Relative density was also measured from the exposed sandy clay soils from the aforementioned slide by measuring the unit weight from brass rings. Relative density was also gauged from observing the excavations performed by a John Deere 16OLC backhoe. See the soils testing section below for specific testing results. 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 Washington—Northwest Quadrant" (2002), the site geology is composed of both glacial till (QW) and advance outwash (Qga). The glacial till is primarily located in the upper portion of the property such as the building areas,and the advance outwash is shown to be within the lower site geology. Envirotech Engineering Geotechnical Investigation PO Box 984 page 5 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 Glacial till, Qg,, is unsorted, unstratified, highly compacted mixture of clay, silt, sand, gravel, and boulders deposited by glacial ice;may contain interbedded stratified sand, silt, and gravel. Advance outwash, Qga, is glaciofluvial sand and gravel and lacustrine clay, silt, and sand deposited during the advance of glaciers; sandy units commonly thick, well sorted, and fine grained,with interlayered coarser sand,gravel, and cobbles;locally contains nonglacial sediments and deposits mapped as transitional between glacial and nonglacial. 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 described utilizing the Unified Soil Classification System (USCS). Using the USCS in conjunction with estimated relative densities and other anticipated engineering properties of the soil, susceptibility for potential landslides, erosion and seismic hazards may be assessed. The Project is composed of native soils with no indications of borrowed fill. For engineering purposes,these native soils consist of distinguishable layers,as presented below. Soils within the upper 15 feet of natural ground were observed to be moist, brown and grey sitly sand (SM) with traces of gravel, cobbles and boulders. This soil description generally includes gravel in the upper 18 inches from the ground surface. Sand content was primarily well graded near the surface, and significant fine sands at depths of over 10 feet. The fines content exhibited low plasticity with small layers of medium plasticity. Weak to moderate cementation was observed throughout test pit 1,and the upper 12 feet of test pit 2. According to the well report soils below the upper 20 feet soil layer consists of brown sandy clay (SC), which extends to a depth of 80 feet below the ground surface. This soil was verified at the face of the recent landside located near the slope toe on Lot 5. 3.3.1 Groundwater From the water well report and knowledge of the general area, permanent groundwater is approximately 150 feet directly below the property at an elevation of about 100 feet above sea level. Perched groundwater at shallow depths was not observed on-site, nor indicated on the well reports. Seepage during wet weather was apparent near the toe of the steep slopes on Lots 4 and 5. 3.4 Soils Testing The soil samples obtained at the Project site during the field investigation were preserved and transported for possible laboratory testing. Visual classification of soils was performed in the field. The following soil tests were performed in accordance with the American Standards for Testing and Materials (ASTM): 8 Visual Classifications(ASTM D2488); Envirotech Engineering Geotechnical Investigation PO Box 984 page 6 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 1 Sand cone test(ASTM D1556); 1 Brass ring unit weight test; and, 1 Direct Shear(ASTM D3080). The results from the visual classification are presented above in the Subsurface Conditions Section at depths of up to 35 feet below the natural ground surface. Specifically, upper sandy soils consisted of approximately 30% gravel, 50% sand-sized soils, and 20% silt. Variations included as a silt content ranging from 10% to 25%, and gravel content of less than 5%. The underlying clayey soils consisted of approximately 0% gravel, 35% sand, and 65% medium plastic clay. A sand cone test, completed by Envirotech was performed near test pit 1. This test indicated that near surface dense, low to moderately cemented soils had a moisture content of 8.1%, and a dry density of 128.1 pcf. One unit weight test was performed by Envirotech by measuring the soils within brass rings that were driven in the exposed clayey strata.This test indicated an in-situ density of 142.2 pcf. Direct shear testing of the weakest substructure was performed by HWA Geosciences, Inc., via PSI. The direct shear test was prepared by remolding the minus No. 4 material to a dry unit weight of approximately 110 pcf, and a moisture content of about 10%. Three shear trials were run at normal stresses of 2.0, 4.0 and 8.0 ksf. The apparent strength parameters from the direct shear test indicated soil cohesion of 70 psf,and an angle of internal friction of 32.8 degrees. Envirotech Engineering Geotechnical Investigation PO Box 984 page 7 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 4.0 ENGINEERING ANALYSIS,CONCLUSIONS AND RECOMMENDATIONS The following sections present engineering analysis and recommendations for the proposed improvements of the Project. These recommendations have been made available based on the planned improvements as outlined in the Introduction Section of this report; general observations including drainage and topography as recapitulated in the Surface Conditions Section; and, soil conditions that were identified from the geotechnical investigation that is summarized in the Subsurface Investigation Section. Engineering analysis and recommendations for the Project that is provided herein, includes pertinent information for building foundations, earthwork construction, slope stability/erosion control,drainage,vegetation and seismic considerations. 4.1 Building Foundation Recommendations Recommendations provided in this section account for the site development of a typical one- or two-story, single family residential structure. Below the upper 12 inches of Project soils, there is apparently one distinguishable layers of soil that will influence the bearing capacity and settlement of the structures. 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, and deriving probable relative densities, unit weights and angles of internal friction of the in-situ soils based on observed field conditions and soil testing for this Project. 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 moderate frost susceptible characteristics and should be used only to the extents provided in this report. 4.1.1 Bearing Capacity For the existing site conditions, bearing values should increase with depth. 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. Footing width and depth recommendations shall be adhered to, and are based on 1500 pounds per square feet (psf) maximum structural bearing pressure. For a bearing capacity requirement of no more than 1500 psf, a minimum footing width of 15 inches shall be placed at a minimum of 18 inches below the existing ground surface. Foundation recommendations are made available based on adherence to the remaining recommendations that are provided in this report. For foundations placed in building pads consisting of engineered fill, 12-inch footings may be used at a depth of 12 inches below the final ground surface. 4.1.2 Settlement Envirotech Engineering Geotechnical Investigation PO Box 984 page 8 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 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. 4.1.3 Concrete Slabs-on-Grade Interior slabs, if utilized, should be supported on a minimum of 6 inches of compacted coarse, granular material that is placed over undisturbed native subgrade or engineered fill. Native soils found at the Project site are not suitable for use as the material directly beneath concrete slabs. The top 4 to 12 inches of native soil should be removed prior to the placement and compaction of the aforementioned 6-inch coarse, granular material. Although not required for the structural integrity of the concrete slab-on-grade, a vapor barrier is usually used for damp-proofing. If vapor barriers are used, it is suggested to utilize a barrier that is sufficiently thick to resist puncturing during construction,or place a 2 inch layer of sand above the barrier prior to placing the concrete slab. 4.2 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 60 pcf for backfill consisting of engineered fill and native soils, respectively. 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 retaining structures with relatively flat or descending sloping backfill, and the backfill conforming to the recommendations outlined in the Earthwork Construction Recommendations Section of this report. For instances when it is necessary to require ascending sloping backfill or structures will 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,inclination of backfill slope is estimated,and the final wall height is determined. 4.3 Earthwork Construction Recommendations Founding material for building foundations shall consist of undisturbed native soils. Compacted engineered fill, or selective re-compacted native soils may be used to the extents provided in this Earthwork Construction Recommendations Section. The following recommendations include Envirotech Engineering Geotechnical Investigation PO Box 984 page 9 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 excavations, subgrade preparation,type of fill, and placement of fill for building foundations. 4.3.1 Excavation Excavation is recommended to remove any excessive organic content or other deleterious material, if present, beneath foundations and to achieve appropriate foundation depth. Additional sub-excavation will be required for this Project if the soils below the required foundation depth are loose, saturated, or otherwise incompetent due to inappropriate land disturbing, or excessive water trapped within foundation excavations prior to foundation construction. All soils below the bottom of the excavation shall be competent, and relatively undisturbed or properly compacted fill. If these soils are disturbed or deemed incompetent, re-compaction of these soils below the anticipated footing depth is necessary. Excavations shall be completely dewatered, compacted, and suitable before placement of additional native soil, engineered fill or structural concrete. It is suggested that foundation excavations are inspected by a geotechnical engineer or qualified professional in order to assess the bearing material prior to the placement of structural footings. 4.3.2 Placement and Compaction of Native Soils and Engineered Fill For engineered fill or disturbed native soils that will be utilized as fill material directly beneath foundations, observation and/ or geotechnical testing is recommended 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 ENGINEERED FILL I I—I I T —I I UNDISTURBED SUBGRADE Both engineered fill and native soils used as compacted fill should be free of roots and other organics, rocks over 6 inches in size, or any other deleterious matter. Engineered fill should consist of 60%to 100% gravel-sized material (particles between 3/16-inch and 3 inches), and less than 10%fines(particles passing#200 standard sieve)by weight. Compaction shall be achieved in compacted lifts not to exceed 8 inches and 12 inches for native soils and engineered fill, respectively. Each lift should be uniformly compacted to at least 95% of the modified Proctor maximum dry density (ASTM D 1557) and within 3% of optimum moisture content. Each lift surface should be adequately maintained Envirotech Engineering Geotechnical Investigation PO Box 984 page 10 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 during construction in order to achieve acceptable compaction and inter-lift bonding. 4.3.3 Retaining Wall Backfill Native soils may be used as retaining wall backfill for this Project. 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). Over-compaction should be prevented since this will cause lateral earth pressures to increase, which may be detrimental to the retaining structure. If clean, coarse gravel soils are utilized as engineered fill, compaction may be achieved from 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.At the ground surface,backfill should extend horizontally from the face of the retaining wall to at least 2 feet in back of the wall for every 4 feet in height. Perforated drains for retaining walls should have a minimum diameter of 4 inches and direct water to an appropriate outfall as recommended in the Surface and Subsurface Drainage Section of this report. Coarse,clean gravel is recommended to be placed at least 12 inches around the drain pipe in order to provide increased drainage capabilities. Non- woven geotextile filter fabric should be wrapped around the aforementioned coarse gravel for reducing the potential of silt migration and clogging of the drain pipe. 4.3.4 Wet Weather Considerations Due to the types of subsurface soils, additional provisions may be required during prolonged wet weather. Every precaution should be made in order to prevent free moisture from saturating the soils within excavations. If the bottom of excavations used for footing placement changes from a moist and dense/hard characteristic as presented in this report to muck or soft, saturated conditions, then these soils become unsuitable for foundation bearing material. If this situation occurs, a geotechnical engineer should be notified, and these soils should be completely removed and replaced with compacted engineered fill or suitable native material as presented in this section. 4.3.5 Building Pads Building pads for this Project 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 not exceed 12 feet for this Project unless approved by a geotechnical engineer. 4.4 Slope Stability and Erosion Control 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 Envirotech Engineering Geotechnical Investigation PO Box 984 page 11 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 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. 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. Surficial slope movements have occurred are expected to continue naturally on the steep descending slopes during times of extreme inclement weather. It is our opinion that these successive shallow landslides will not threat the planned development during the design life of the structures. 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,located within the building areas, 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, topography, and the presence of surface sloughing. An 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 may be found below in this report this report. According to the Resource Map from the Washington State Department of Natural Resources (DNR), the Project is not within terrain labeled `highly unstable' or `highly erodible' relating to soils. In addition, DNR did not indicated previous landslide activity near the Project. DNR labeled portions of this project as 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 considering the specific site geology or soils.A DNR map is provided below in this report. The Simplified Bishop Method, utilizing `STABLE' software, was used to analyze the static stability of the site slopes. 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, and cohesion of the site soils. STABLE software has been repeatedly checked with manual calculations, and consistently proved to be a very conservative program. The following soil properties were used in the analysis, and are based on observed conditions, known geology, and/or published parameters: Top 2 feet of weathered soils • Soil unit weight: 132 pcf • Angle of internal friction: 30 degrees • Cohesion: 100 psf Soils from 2 feet to 12 feet Envirotech Engineering Geotechnical Investigation PO Box 984 page 12 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 • Soil unit weight: 135 pcf • Angle of internal friction: 39 degrees • Cohesion: 400 psf Soils from 12 feet to 20 feet • Soil unit weight: 110 pcf • Angle of internal friction: 34 degrees • Cohesion: 100 psf Soils below 20 feet • Soil unit weight: 130 pcf • Angle of internal friction: 30 degrees • Cohesion: 1000 psf 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. Envirotech Engineering Geotechnical Investigation PO Box 984 page 13 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 Anticipated building loads, building pads or cuts, are not expected to have any detrimental influence on the global stability of the slopes, provided that the setback requirements, drainage and all other recommendations in this report are adhered to. Based on the aforementioned Project criteria, observations, slope stability analysis, and the recommendations in this report, the building locations have an acceptable factor of safety of over 1.5 relative to deep-seated, static slope failures. Furthermore, an acceptable factor of safety of over 1.1 for seismic conditions was also concluded for this Project. See the slope stability information in Appendix D for input parameters and example of outputs. r ? �� F rV �rV5508 170 0 1 1705W E Laka AnEsrson 2,, f 05548.E 1705040 1705042 / t70504a -. I - �/ S PUYut EounG e Project l �-170 - 30 x1 : ,41 ={ Map from Washington State Department of Natural Resources Envirotech Engineering Geotechnical Investigation PO Box 984 page 14 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 3 M1. O sr 0 J= 0- Project U �4 • .4 01 ON a =? s .... Rocky P In i ! s R�F. U Scale 1:24,000 O ! I Alils , o aa1 IWO I WO Met— Map from Washington State Department of Ecology Website The aforementioned slope stability factors of safety are for the planned building sites. This model depicted safe building sites beyond 40 feet from the top of steep descending slopes. Site conditions and the slope stability model concluded unstable descending slopes. Several slope stability analyses were performed for this Project, and one extremely conservative analysis with relation to site topography and soils is presented herein. The topography was modeled based on potential future conditions due to successive shallow slides. This model included moderate slopes of nearly 20% beyond the top, 10% grades beyond the toe, and an 86% slope with a vertical relief of 100 feet. These grades are excessive with relation to probable conditions during the design life of the structures. Soil inputs, as provided above, were based on direct shear testing for the weakest structure, field testing for the upper dense soils, and laboratory testing for the underlying clay layer. Both published soil characteristics and direct correlation of specific soils testing for this Project Envirotech Engineering Geotechnical Investigation PO Box 984 page 15 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 provide greater strength parameters than what was used in the analysis. 4.4.1 Septic Drainfield Impacts Septic drainfields are not anticipated for this Project due to future plans of stubbing into a municipal system. 4.4.2 Building and Footing Setbacks Provided that assumptions relating to construction occur and recommendations are followed as presented in this report,the factor of safety for slope stability is sufficient for a 40 feet footing setback from the face of the nearby descending slopes exceeding 40%. See the figure below and the Geologic Map in Appendix B for an illustration of the setbacks. STRUCTURE TOP OF SLOPE E St13PE FACE IT 1.1 -I I 40 FT h•1IN �� FOOTING In addition, footings shall have a minimum setback of 5 feet from the top of building pads consisting of engineered fill. 4.4.3 Temporary and Permanent Erosion Control Based on the USCS description of the Project soils, the native soils have a moderate erodibility factor. Temporary and permanent erosion control measures will be required for site development. Existing erosion control present on-site such as silt fencing appear to be sufficient for this Project. Additional temporary erosion control measures may need to be employed if excessive erosion occurs or required by the County or other prevailing agencies. See Appendix A for approximate locations of existing erosion control facilities. A stormwater management plan has been prepared for this Project, and addresses appropriate temporary and permanent erosion control. 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. Permanent erosion control is required per the stormwater management plan,and may also be necessary if substantial vegetation has not been established within disturbed areas upon completion of the Project. Temporary erosion control should remain in place until permanent erosion control has been established. Permanent erosion control may include Envirotech Engineering Geotechnical Investigation PO Box 984 page 16 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 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. Sedimentation control should be adequate when utilizing the erosion control recommendations as presented herein together with implementing appropriate erosion controls with the degree of care as expected from a licensed contractor. Erosion control information and specifications in addition to what is provided in this report may be found in the appropriate "Stormwater Management Manual for Western Washington,"prepared by the Washington State Department of Ecology Water Quality Program. 4.4.4 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. Both footing perimeter drains and roof drains are required for this Project. Subsurface water intercepted in the footing perimeter drains, and stormwater collected from roof drains shall be tight-lined to an appropriate outfall location beyond the toe of the steep 40%+ slopes. Recommended outfall locations are delineated on the Geologic Map in Appendix B, and optional drainage details for tightlining are provided in Appendix F of this report. 4.4.5 Vegetation Considerations Vegetation is an excellent measure to minimize sur cial 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. For existing conditions, vegetation shall not be removed on the face of the steep slope or within 40 feet from the top of the slope. This buffer may be reduced 15 feet as necessary for construction. However, any tree deemed hazardous to life or property shall be removed. If tree removal is necessary, then stumps and roots shall remain in place, and the underbrush and soil shall remain undisturbed as much as possible. Any disturbed soil shall be graded and re-compacted in order to restore the terrain similar to preexisting conditions and drainage patterns. See the Geologic Map in Appendix B of this report for Envirotech Engineering Geotechnical Investigation PO Box 984 page 17 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 a depiction of the vegetation buffer. 4.4.6 Off-site impacts From a geotechnical position,it is Envirotech's opinion that the adjacent properties to the proposed development should not be significantly impacted as a result of this development if all recommendations in this report are followed. This is based on the expected site development,and the recommendations presented in this report. 4.5 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 2 miles to the south of this Project. This information is based on the USGS Quaternary Fault and Fold Database for the United States. The potential for liquefaction and other earthquake induced hazards are believed to be low for this Project. This is based, in part, on the slope stability analysis utilizing seismic considerations in addition to 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. Although gravel- and silt-sized soil particles could be problematic, fine and medium grained sands are typically subjected to these types of seismic hazards. No significant saturated sand stratifications are anticipated to be within the upper 50 feet of the subsoil for this Project. Envirotech Engineering Geotechnical Investigation PO Box 984 page 18 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 5.0 CLOSURE Based on the project information and site conditions as presented in this report, it is Envirotech's opinion that additional geotechnical studies are not required to further evaluate this Project. Due to the inherent natural variations of the soil stratification and the nature of the geotechnical subsurface exploration, there is always a possibility that soil conditions encountered during construction are different than those described in this report. Therefore, it is recommended that a qualified engineer observes and documents the construction, or Envirotech is promptly notified if project and subsurface conditions found on-site are not as presented in this report so that we can re-evaluate our recommendations. This report presents geotechnical design guidelines, and is intended only for the owner, or owners' representative, and location of project described herein.This report should not be used to dictate construction procedures or relieve the contractor of his responsibility. Any and all content of this geotechnical report is only valid in conjunction with the compliance of all recommendations provided in this report. Semantics throughout this report such as `shall,' `should' and `recommended' imply that the correlating design and/or specifications must be adhered to in order to protect life and property. Semantics such as `suggested' or `optional' refer that the associated design or specification may or may not be performed. The recommendations provided in this report are valid for the proposed development at the issuance date of this report. Changes to the site other than the expected development, changes to ordinances or regulatory codes, or broadening of accepted geotechnical standards may affect the conclusions and recommendations of this report. The services described in this report were prepared under the responsible charge of Michael Staten, a professional engineer with Envirotech. Michael Staten has appropriate education and experience in the field of geotechnical engineering in order to assess landslide hazards, earthquake hazards,and general soil mechanics. Please contact Michael Staten at 360-275-9374 if you have any questions, comments, or require additional information. Sincerely, E��Envirotechh Engineering — Michael Staten,P.E. Geotechnical Engineer Envirotech Engineering Geotechnical Investigation PO Box 984 page 19 Knudsen Tracts Belfair,Washington 98528 Mason County,Washington Ph. 360-275-9374 June 12,2008 A SCALE, 1 INCH = 150 FEET PROPOSED ACCESS:77-- 140 120 0®0 200 160 75 i / 1113' / \ 11/ i ANTI PATE O TED 100 HUIL NG ATED LOCATION ION III_ NTE �TED Bu1Lt[N QED LOCH ION T�2 so ANTIC PA ANTI PATED �le BWL➢NG LOCATI HUI NG LOCA I 60 SILT FENCE L 8 LOCH ION IO Ta] � 2 LOT 1 ^ 40 Y AN7T��C PAT OT 7 a, BUILD NG i IpN ROPOSED LOT DETENTION J \rr BASIN LOT 9 V 102, 213' LOT LOT 4 POSSIBLE RETENTION/ DETENTION 83 AREA r �P T W L C I 4 EXISTING ACCESS ROAD PROJECT/ OWNER/ LOCATION. PROPOSE KNUDSEN TRACTS /T 5 ET NT LEGEND GE❑TECHNICAL REPORT JACK JOHNSON CONSTRUCTION, LLC 41TP1 TEST PIT SHERWOOD CREEWK ROAD, ALLYN ` MASON COUNTY, WASHINGTON 1 �1SL❑PES ENGINEER- _-75—" EXISTING CONTOUR ENVIROTECH ENGINEERING T 3 30' 74 NE HURD ROAD SILT FENCE OR APPROVED BELFAIR, WASHINGTON 98528 EROSION CONTROL 360-275-9374 SITE PLAN APPENDIX B GEOLOGIC MAP SCALE. 1 INCH 150 FEET PROPOSED ACCESS ROAD 120 140 200 180 160 0®0 1113' 9 TEO AN PATE PgTEO 1 100 BUILD NG ANTI PATE ANT PATED UIL NG N lON BUIL NG TED BUf 0 AT COCA ION / 80 ANTIC PATE W TP BUILD NG I L CATIO A ION BUIL ING LPT B COCA ION LOCA IW 60 T�1 40 2 LOT 1 io ^ 10F UItD S ACK VE ETA ON BUF EG[TA?ION FFER NOT ME ETHAN ON-TOP OF LOP FEET AS NECE$$ ARY ANT]C P EDrA EX EOING 40X _FO C13NSTRUL`TBUILD ROPCOCA 1 ti TION QSEZT LOT SINLO 9 TMATE TOP OF 102'EXCEE➢IN 3' LOT 4 APPROXIMATE TOE OF SLOPES EXCEEDING 40% SEWERS ARE TO BE P STUBBED INTO �N N/ SOILS. DENSE SILTY LOCAL COMMUNITY DETENTION SAND OVERLYING SYSTEM 83 !< AREA HARD SANDY CLAY W C T 4 N EXISTING ACCESS ROAD PROJECT/ OWNER/LOCATION KNUDSEN TRACTS ROP SE GE❑TECHNICAL REPORT 5 ET ASI TI LEGEND JACK JOHNSQJ CONSTRUCTION,LLC eTPI TEST PIT SHERWOOD CREEWK ROAD, ALLYN MASON COUNTY, WASHINGTON -�i SLOPES ENGINEER, ENVIROTECH ENGINEERING 75 EXISTING CONTOUR 74 NE HURD ROAD Th I BELFAIR, WASHING ON 98528 f-� SILT FENCE OR APPROVED 360-275-9374 EROSION CONTROL GE❑L❑GIC MAP VERTICAL AND HORIZONTAL SCALD 1 INCH_ 40 FEET_ PROPOSED HOUSE -b 0 v 2C' MED. TO DENSE SILTY SAND (SM) LOW TO MODERATE CEMENTATI❑N V� BROWN, HARD SANDY CLAY (CL) GLACIAL TILL PROJECT/ OWNER/ LOCATION- KNUDSEN TRACTS GE❑TECHNICAL REPORT JACK JOHNSON CONSTRUCTION,LLC SHERWOOD CREEWK ROAD, ALLYN MASW COUNTY, WASHINGTON NOTES, ENGINEER, 1) GRADE CHANGES WILL BE COMPLETED PER THE STORMWATER ENVIROTECH ENGINEERING MANAGEMENT PLAN AS EXPLAINED IN THE GEOTECHNICAL REPORT, SECTION A-A 74 NE HURD ROAD 2> THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF BELFAIR, WASHINGTON 98528 THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS. 360-275-9374 LOWER DEPTHS ARE BASED ON SITE GEOLOGY, WELL LOG(S),AND/OR EXPERIENCE IN THE GENERAL AREA. SOIL PROFILE TEST PIT LOG TEST PIT NUMBER TP-1 PROJECT: Geotechnical Report DATE OF LOG: 05/16/2008 PROJECT NO: 0857 LOGGED BY: MCS CLIENT:J.Johnson Construction, Inc EXCAVATOR: Thomas Sharpe LOCATION: Parcel 122203300210, 122292200320, 122203390221, DRILL RIG: Deere 160 LC backhoe 122203390222, 122203390223,&122203390224 ELEVATION: N/A Mason County,Washington 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 ....... ...................I...................... SM Brown,moist SILTY SAND with GRAVEL,loose to medium dense.Gravel is coarse.Sand is fine.Low plasticity. 2 Dense to very dense,brown and gray Low to modeately cemented,trace of gravel 4 Increasing coarse gravel 6 Occasional cobble 8 10 12 14 Excavation terminated at approximately 16 15.0 feet 18 20 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this boring and should not be Geotechnical Engineering interpreted as being indicitive of the entire site. TEST PIT LOG TEST PIT NUMBER TP-2 PROJECT: Geotechnical Report DATE OF LOG: 05/16/2008 PROJECT NO: 0857 LOGGED BY: MCS CLIENT:J.Johnson Construction, Inc EXCAVATOR: Thomas Sharp LOCATION: Parcel 122203300210, 122292200320, 122203390221, DRILL RIG: Deere 160LC backhoe 122203390222, 122203390223,&122203390224 ELEVATION: NIA Mason County,Washington 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 ........................................... SM Brown,moist SILTY SAND with GRAVEL,loose to medium dense.Gravel is coarse.Sand is fine.Low plasticity. 2 z Dense,brown and gray,patches of low to medium plasticity,occasional cobble or boulder 4 Dense to very dense,brown and gray, low to moderate cementation 6 8 10 12 Medium dense to dense,Increasing fine sand,trace of gravels 14 Increasing densty,increasing coarse oravel Excavation terminated at approximately 16 15.0 feet 18 20 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this boring and should not be Geotechnical Engineering interpreted as being indicitive of the entire site. SOIL LOG TEST PIT NUMBER TP-3 PROJECT: Geotechnical Report DATE OF LOG: 05/16/2008 PROJECT NO: 0857 LOGGED BY: MCS CLIENT:J.Johnson Construction, Inc EXCAVATOR: NIA LOCATION: Parcel 122203300210, 122292200320,122203390221, DRILL RIG: None 122203390222, 122203390223,&122203390224 ELEVATION: N/A Mason County,Washington INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A SOIL STRATA, STANDARD PENETRATION TEST DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE AND TEST DATA DEPTH N 10 30 50 SM Brown and gray,moist SILTY SAND with GRAVEL,loose to medium dense 4 - Dense 8 12 16 20 Sandy,clay pocket 24 28 32 Hardpan 36 Excavation terminated at approximately 35.0 feet 40 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. SOIL LOG TEST PIT NUMBER TP-4 PROJECT: Geotechnical Report DATE OF LOG: 05/16/2008 PROJECT NO: 0857 LOGGED BY: MCS CLIENT:J. Johnson Construction, Inc EXCAVATOR: N/A LOCATION: Parcel 122203300210, 122292200320, 122203390221, DRILL RIG: None 122203390222,122203390223,&122203390224 ELEVATION: N/A Mason County,Washington INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A SOIL STRATA, STANDARD PENETRATION TEST DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE AND TEST DATA DEPTH N 10 30 50 SM Brown,moist SILTY SAND with GRAVEL,loose to medium dense.Gravel is coarse"Sand is fine.Low plasticity. 2 4 6 CL Brown,hard,low moisture,SANDY LEAN CLAY.Medium plasticity 10 Excavation terminated at approximately 10.5 feet 12 14 16 18 20 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this boring and should not be Geotechnical Engineering interpreted as being indicative of the entire site. SOIL LOG TEST PIT NUMBER TP-5 PROJECT: Geotechnical Report DATE OF LOG: 05/16/2008 PROJECT NO: 0857 LOGGED BY: MCS CLIENT:J.Johnson Construction, Inc EXCAVATOR: N/A LOCATION: Parcel 122203300210, 122292200320, 122203390221, DRILL RIG: N/A 122203390222,122203390223,&122203390224 ELEVATION: N/A Mason County,Washington 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 . . .................. .......... SM Brown,moist SILTY SAND with GRAVEL,loose to medium dense.Gravel Is mostly coarse.Sand Is fine and 2 medium.Low plasticity. Dense to very dense,brownish gray, hardpan 4 6 8 10 12 14 16 Excavation terminated at approximately 16.0 feet 18 20 No Groundwater Encountered ENVIROTECH ENGINEERING This information pertains only to this boring and should not be Geotechnical Engineering interpreted as being indicitive of the entire site. 6- v WATER WELL-REPORT- CURRENT r' Original dr l'copy-Ecology,Yr copy-owner,Y'ropy-driller Notice of•Intent No. W 190101 e t'o'i'0Ic'r -Unique Ecology Well ID Tag No. Aw 421 V Construction/Decommission,("x"incircle) a 70 Construction Water Right Permit No. a O Decommission ORIGINAL INSTALLATION Notice Party Owner Name Jack Johm9m C � �� of Intent Number Well Street Address Chan wri C eelc Rd_ O PROPOSED USE: t Domestic a ledusntal 13 Municipal_ City_�� County Mason DeWater -O Irrigation- 0 Teo Well O Othtt. C Location"/4-1/4SN�114 Seems Twn�R IN aM arse TV PE OF WORx: Owner's number of wen(if more than one) ono wwki 30 New well O Reconditioned Method:0 Dug- 0 Bored D Driven Laf/L,on i Lat Deg_ Lat Min/See o Deepened QCeAt a Riney.-• t]Jetted gS,tr EDIMENSIONS:Diameterofwell(_inches,drilled tan n- ' Still REQUIRED) Long Deg LongMin/Sec D Depth of completed well 1 AO A C CONSMUCTION DETAIL Tax Parcel No. 12220-33-00210 Casing 30 Welded 6 Dram.from -+1 R to l 75 tL - C - Iertalled:. 0 Liircr installed Dim tram. R m n. CONS•J'RUCI•ION OR DECOK%U,SION PROCEDURE y _ ❑Threaded Diann.from R.to 4L V Perforations: ❑Yes m No Formation'Desenbe by color,character•sill of rreteriei and unsctae,and the kind end nature of the material in each stranan Penetrated;with at least one entry for each change of �• T ypeofpMoratorused informanen. USE ADDITIONAL SHEETS IFNECESSARY. CSIZE ofperfi In by, -tn.and no.ofperfa_from_fl'oo •• fl. MATERIAL FROM TO 0 screens: )3 Yea 0 No R X-Pee Location 1J3 RManufacniter's Name t fL11LnSon Type -f-Ai nl aaa Model No. rlb 'Soil 0 2 DIM._t—Sslat,.sze . 40 [rota Diam ws fl.m_• 1.8o n- . sae Ram n.m 8 CGrffwlTvher packed:0 Yes 0 No. 0 Sint ofgravd/seed - W Materials Placed fiom R m - n. Surface Seal:QYes 0 No To wheadepth? flandy brown clay C Malerial used in seal Bpt•nni t-a - 6. Did any strata contain unusable wateR 0 Yes QNo BrO47r1 till 80 150 IO Type of water? Depth of stun MethadoraealirtgsaatsaD Saul $ Gravel with water 150 180 _ PUMP:Manufawrer's Nance Gouids ' Type: iuh_ HP. 3 WATER LEVELS;Land-surface devotion shove roan sea keel` ft %! Static level 8-4 5 n.belowtopofwell Due' Artesian pressure lbs.per square inch Date Arrest.water is controlled by - � M. WELL TESTS:Dawdown is arrout water level is lowered below static level Was a pump test made?0 Yes A3 No If yes,by whom? VYield' gallmirs with ft.dmwdown after la's.Yield. Aal Jntin with ft.drawdown after hrs. Y.Id 0.1min.with ft drawdown aflcr m. O Recovery ilub fl/me�km as:ero vhsn pump tamed ob).(water flvef,aiasnreeJ n wall_. top to water fewll spa C Time Water Level Time Water Level Time Water Leval Date of teat G s 3. Bailer tea -gallmin with_ .70 fl.drawdown Ov,1Ius. e ? Asrsest gaiJin .with stem set a R.for III& y Artesian now A P.-Date Temperature of water_Was a cbemical analysis rode? O Yes 30 No• - StartDaba 8(25/05 Completed Date 10/16/05 WELL CONSTRUCTION CERTIFICATION: 1 constructed and/or accept responsibility for construction of this well,and its compliance with all Washington well construction standards. Materials used andthe information reported above are true to my best knowledge and belief. MDriiler GEn;ineer OTrainee Name(Print) Drillingcompany tlaari g nrj,ll ing DrinerlFngineerfrrmnee signatwe ��-� \ —� Address -ran NR rlaVyg�a�Rrl .Drdierornaittee License No. 79.7 - City,state,Zip P-I fain WA A8$28 _ If TRALVEE, .. Contractor's .. Driller'a Licemed No. Registration No.DAVISDI1 1 ODA Date 1•rt- 05 Driller's Signature - Ecology is an Equal Oppommiry Employer ECY o50-1-Zo(Rey 3ros) The Department of Ecology does NOT warranty the Data and/or Information on this Well Report. STABLE Slope Stability Analysis System Envirotech Engineering Project Knudsen Tracts Datafile: final static Bishop STABLE Version 9.03.00u Bishop ##rr#rr+++rrr#+++rr++srrrrrr+wr+rrrrwrrwrr4#rrrr:#wrrrr#rr TITLE final static #r44rr44444+##4r#r#+##+4####r#+#f 4+4r4#i+#+#+r4rr44+i+4rrw UNITS (Metric/Imperial) - I GEOMETRY DEFINITION POINTS NO. x Y 1 0.000 0.000 50.000 5.000 3 166.000 105.000 4 :66.000 123.000 5 26.600 2.660 6 37.800 3.780 7 49.000 4.900 8 60.200 13.79D 9 71.400 23.450 10 82.600 33.100 11 93.800 42.760 12 105.000 52.410 13 116.200 62.070 14 127.400 71.720 15 138.600 81.360 16 149.800 91.030 17 161.000 100.690 18 172.200 106.120 19 183.400 108.130 20 194.600 110.150 21 205.800 112.160 217.000 114.190 23228.200 116.200 25 0.000 -2.000 26 50.000 3.000 27 166.000 103.000 28 266.000 121.000 29 0.000 -14.000 30 50.000 -9.000 31 166.000 91.000 3: 266.000 109.000 33 0.000 -20.000 34 50.000 -15.000 35 166.000 85.000 36 266.000 103.00D 37 206.000 112.200 38 206.000 110.200 LINES Lo X Hi X SOIL 1 1 3 1 STABLE®2002 MZ Associates Ltd Printed on: 11106/08 @ 15:38:36 Page: 1 STABLE Slope Stability Analysis System Envirotech Engineering Project Knudsen Tracts Datafile: final static Bishop 3 37 _ 37 4 1 25 26 2 26 27 a 27 38 2 38 28 2 29 30 3 30 31 3 31 32 3 33 34 5 34 35 5 35 36 5 «*f«f+rf.lrfrffllrrwrrrrrwrrww♦:r*rrrw+.+wrawarrraa+a•rr4• SOILS SOIL NAME __..___=-- at COHESION FRICTION UNIT WT. 1 Soil-1 100.00 30.0 132.000 2 Soil-2 __..___ ... -BLUE 400.00 39.0 135.000 3 Soil-3 100.00 34.0 110.000 5 Soil-5 __NUOUS-CYP.N 1000.00 30.0 130.000 6 Soil-6 _:N-INUOUS-GRAY 0.00 0.0 0.000 .f.11f.4...fw.f.wf.11f«4**4.44fYYY*Y4.+r}ra/raw*r*w*#*wi#* PORE PRESSURE SPECIFICATION SOIL PIEZO RU EXCESS Y/N/P Value Value 1 N 0.000 0.000 N 0.000 0.000 3 N 0.000 0.000 5 N 0.000 0.000 6 N 0.000 0.000 PIEZOMETRIC SURFACE POINT POINT PORE PRESSURES POINT PRESSURE SLIP DIRECTION (+/- %) - *.****.*f.*#.1f.k*«*.***aa•*4*****«******«««4.i4a..4f•«.ii SLIP-CIRCLES MANUAL Circle Centre Grid Extremities 335.800 STABLE:R.2002 MZ Associates Ltd Printed on: 11106/08 @ 15:38:36 Page: 2 GEOTEXTILE FABRIC 2'x2' WOOD POST (TYP) GEOTEXTILE FABRIC WRAP AROUND TRENCH OR EQUIVALENT OR BETTER AND WIRE MESH TO AT LEAST ENTIRE 8 6 FT MAX.D.C. BOTTOM ()F TRENCH 0.5 FT BEFORE PLACING GRAVEL 6 FT 2's2'x5' WOOD POST OR 12' DEEP, 8'WIDE TRENCH EQUIVALENT OR BETTER EXISTING FILLED VITH 3/4' TO 1 1/2'� GROUND SURFACE WASHED GRAVEL 2 T DIRECTION OF—y 2.S1FI 12'DEEP,8' WIDE WATER FLOW GROEXIUND SURFACE ING TRENCH FRLED WITH 1Tk7 } 12' 3/4'TO I i/2' T e.51 F7 T� eZ IT WASHED GRAVEL i g' T BOTTOM EXTENTS OF 1 GEOTEXTILE FABRIC SILT FENCE- nETAD_ SILT FENCE-CROSS SECTION N.T.S. NT.S. PERMANENT EROSION CONTROL NOTES. GENERAL NOTES- SOD PLACEMENT L SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON L SOD FOR GRASS SWALES SHALL BE MACHINE CUT AT A THESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR 3/4-INCH UNIFDRH THICKNESS AT THE TIME OF CURING. SHALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. MEASUREMENTS FOR THICKNESS SHALL EXCLUDE TOP GROWTH AND 2.ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL HE THATCH INSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. 2. STANDARD SIZE SECTIONS OF SOD FOR GRASS SWALES SHALL 3. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN BE STRONG ENOUGH TO SUPPIXiT THEIR OWN WEIGHT AND RETAIN PLACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED. THEIR SIZE AND SHAPE WHEN SUSPENDED BY THE END OF A 3 TEMPORARY EROSION CONTROL NOTES. FOOT SECTION 3. SOD FOR GRASS SWALES SHALL NOT BE HARVESTED OR FOR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION 1R EXPERIENCED LAND TRANSPLANTED WHEN EXCESSIVELY DRY WET MOISTURE DISTURBING ACTIVITIES, AND WHERE MO FURTHER WORK IS ANTICIPATED FOR A CONTENT MAY ADVERSELY AFFECT ITS SURVIVAL. 4. SOD FOR GRASS SWALESSHALL BE HARVESTED, DELIVERED PERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE IMMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED AND PLACED WITHIN A PERIOD IOD Of 36 HOURS. EROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING SEEDING FOR RAW SLOPES ALONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH SEPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOLF CONTROL THE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES, OR OTHER APPROVED TREATMENT. SWALES,LEVEL SPREADERS AND SEDIMENT BASINS. 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE, DRY SEASON(MAY I THRU SEPTEMBER 30) --THE CLEARING OF LAND, INCLUDING THE FOLLOWING SURFACE ROUGHENING.PERFORM ALL OPERATIONS REMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO ACCROSS OR PERPENDICULAR TO THE SLOPE ONLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE 3.SEEDING RECOMMENDATIONS, AS SHOWN BELOW,AND SHOULD BE OTHERWISE STABILIZED,AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , APPLIED AT THE RATE OF 120 POUNDS PER ACRE. BY NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE 4.SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL STABILIZATION IS SPECIFIED 114 THE EROSION AND SEDIMENT CONTROL PLAN, ALL REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO AREAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED FOSTER AND PROTECT THE ROOT STRUCTURE. THROUGH THE USE OF MULCHING, NETTING,PLASTIC SHEETING,EROSION BLANKETS, 5.SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30, FREE DRAINING MATERIAL,ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED ARMORING OF THE SEED BED WILL BE NECESSARY,(e.g., PLAN ff ACTION UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, GEOTEXTILES,JUTE MAT, CLEAR PLASTIC COVERING). FERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBE➢ AREAS SHALL BE 6.FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' PERFORMED DURING THE FOLLOWING PERIODS- MARCH I TO MAY 15,AND AUGUST 15 TO RECOMMENDATIONS. AMOUNTS SHOULD BE MINIMIZED, ESPECIALLY OCTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION ADJACENT TO WATER BODIES AND WETLANDS. OF THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE TO SATISFACTORY GROWTH.IN THE EVENT THAT PERANENT STABILIZATION IS NOT USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION POSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, CONTROL,OR A COUNTY APPROVED ALTERNATE SEED MIXTURE. PLASTIC SHEETING,EROSION BLANKETS, ETC.,MUST BE INSTALLED BY NO LATER THAN SEPTEMBER 30. PROPORTIONS PURITY GERMINATION IN THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT NAME BY WEIGHT (S) IX) ACTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE (X) OWNER/CONTRACTOR SHALL HE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION AND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT RE➢TOP (AGROSTIS ALBA) 10 92 LEAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR 90 THE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. ANNUAL RYE CLOLIUM MULTIFLORUM) 40 98 90 WET SEASON(OCTOBER 1 THRU APRIL 30)—ON SITES WHERE UNINTERUPTED CHEWING FESUE 40 97 CONSTRUCTION ACTIVITY 1S IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE 80 REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED (FESTUCA RUBRA COMMUTATA) TO AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HUURS IN (JAMESTOWN, BANNER, SHADOW,KO(ET) THE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT WHITE DUTCH CLOVER 10 96 TRANSPORT OFF-SITE IS OBSERVED. 90 ALL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE (TRIFOLIUM REPENS) COVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING,PLASTIC MULCHING SHEETING, EROSION BLANKETS,FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED. 1. MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD SILT FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., WILL NOT BE VIEWED AS FIBER CELLULOSE,AND SHOULD BE APPLIED AT A RATE OF 1000 ADEQUATE COVER IN AND OF THEMSELVES. IN THE EVENT THAT ANY LAND AREA NOT POUNDS PER ACRE, BEING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY 2.MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED STABILIZED 5 DAYS AFTER HAVING BEEN CLEARED,ALL CONSTRUCTION ACTIVITY ON SLOPES GREATER THAN 2-1 (HORIZONTAL.VERTICAL). THE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY,SHALL 3.MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN IMMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON. ALL APPROPRIATELY PROTECTED OR STABILIZED. AREAS REQUIRING MULCH SHALL HE COVERED BY NOVEMBER 1. SILT FENCE PROJECT/ OWNER/ LOCATION 1.GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE 'STORMWATER MANAGEMENT MANUAL KNUDSEN TRACTS FOR THE T SOUND , OR APPLICABLE COUNTY T GEOTEXTILE FILTER FABRIC SHALL BEPURCHASEDIN 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 JACK JOHNSON CONSTRUCTION,LLC TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT JACK OH CREEVK ROAD,ION,L BOTH ENDS TO THE POST. SHERMASON COUNTY, WASHINGTON ALLYN 3. STANDARD FILTER FABRIC SHALL BE MASTERED USING 1' STAPLES OR TIE WIRES (FUG RINGS)E 4 IN SPACING. 4.POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEER- DRIVEN SECURELY INTO THE GROUND. ENVIROTECH ENGINEERING 5. WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVILENT. THE WIRE MESH MAY BE ELIMINATED IF 74 NE HJRD ROAD EXTRA-STRENGTH FILTER FABRIC (MONOFILAMENT),AND CLOSER POST SPACING IS USED. BELFAIR, WAS14NGTON 98528 6. A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE OF THE 360-275-9374 POSTS AND UPSLOPE FROM THE SILT FENCE.7. SILT FENCESSHALLBE LOCATED DGVNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. ER❑SI❑N CONTROL APPENDIX F DRAINAGE DETAILS STEEL CLAMPS RYP) CORRUGATED TIGHTLINE 10 FT MIN SPACING 1/2 INCH DIAMETER 6-INCH MIN. DIAMETER SECURELY FASTENED TO PIPE 8-12 INCH QUARRY SPALL OR APPROVED ENERGY DISSIPATOR LEVEL SECTION TWO 3-FOUT o0000000000.00° ANCHDRS (TYP), I O0000000000000 1 FT MIN. #4 REBAR OR o0O pO DO DO DODO EQUIVALENT 3 FT MIN GEOTEXTILE FABRIC TIGHTLINE DETAILS - OPTION 1 N.T.S. FINAL GROUND SURFACE GEOTEXTILE FABRIC WRAPPED AROUND QUARRY SPALL CORRUGATED TIGHTLINE B-12 INCH QUARRY SPALL OR 6-INCH MIN. DIAMETER APPROVED INFILTRATION MEDIA 1 o O000"ooODODOO 1 FT M� 0000000000000 SUBSURFACE DRAINAGE DETAILS - OPTION 2 N.T.S. NOTE- INFILTRATION FACILITY OR PONDS SHALL BE SIZED FOR PROJECT/ OWNER/ LOCATION. THE IOOYR 24HR STORM EVENT. KNUDSEN TRACTS GEOTECHNICAL REPORT JACK JOHNS13N CONSTRUCTION, LLC SHERWOOD CREEWK ROAD, ALLYN MASON COUNTY, VASHINGT13N ENGINEER- ENVIROTECH ENGINEERING 74 NE HURD ROAD BELFAIR, WASHINGTON 98528 360-275-9374 DRAINAGE DETAILS �wv��otecl� �wg�wee��w� ceotechKicaL- EvWIXovLvvtvLtaL o DraiKage-RoadwalJ. March 23, 2021 Jack Johnson Construction,Inc. PO Box 1119 Belfair,Washington 98528 Sena Smith 300 E Archer Ridge Road Allyn,Washington 98524 RE: Geotechnical Report Addendum#1 for Knutsen Tracts Single Family Residences,Parcel 12220-33-00250,Mason County,Washington Dear Mr.Johnson, Envirotech Engineering (Envirotech) has completed this geotechnical report addendum for the above referenced project. The original report, dated June 12, 2008, was prepared by Envirotech (Project#0857). The project site was revisited by Michael Staten with Envirotech on multiple occasions during the preparation of the original report, subsequent addendum, and inspections. A recent site visit was performed on March 15, 2021 to evaluate the proposed project and verify the absence of new geotechnical hazards since our initial site visit in 2008. We conclude that the natural topographic and geologic conditions were virtually unchanged with relation to the safety of the property. The subject parcel is known as Lot 9 of the Knudsen Tracts within our original report. It is our opinion that the all geotechnical parameters are per current code, and that the development may commence per the original report. Envirotech is pleased to submit this addendum. Please contact Michael Staten at 360-275-9374 if you have any questions,comments, or require additional information. Best Regards, Envirotech En ineenng Pg1.GLYDE Sr NVasy��cRj�2 .' 2 43045 rio RFC/s �SS�ONALENG` 3/23/21 Michael Staten,P.E. Geotechnical Engineer Envirotech Engineering Geotechnical Report Addendum#1 PO Box 984 Page 1 of 1 Knudsen Tracts Single Family Residences Belfair,Washington 98528 Parcel 12220-33-00250 Ph.360-275-9374 March 23,2021 Ev�,vi rotec.k ewO'weer'bwO Geetechwieal 0 6wv%rovwuev4.taL o Dra%Kage o tz.oadwad March 23,2021 Jack Johnson Construction,Inc. PO Box 1119 Belfair,Washington 98528 Sena Smith 300 E Archer Ridge Road Allyn,Washington 98524 RE: Geotechnical Report Addendum#1 for Knutsen Tracts Single Family Residences,Parcel 12220-33-00250,Mason County,Washington Dear Mr.Johnson, Envirotech Engineering (Envirotech) has completed this geotechnical report addendum for the above referenced project. The original report, dated June 12, 2008, was prepared by Envirotech (Project#0857). The project site was revisited by Michael Staten with Envirotech on multiple occasions during the preparation of the original report, subsequent addendum, and inspections. A recent site visit was performed on March 15, 2021 to evaluate the proposed project and verify the absence of new geotechnical hazards since our initial site visit in 2008.We conclude that the natural topographic and geologic conditions were virtually unchanged with relation to the safety of the property. The subject parcel is known as Lot 9 of the Knudsen Tracts within our original report. It is our opinion that the all geotechnical parameters are per current code, and that the development may commence per the original report. Envirotech is pleased to submit this addendum. Please contact Michael Staten at 360-275-9374 if you have any questions,comments,or require additional information. Best Regards, Envirotech Engineering �y CLYDe s WAsy�ti R 43045 cv� DA AGIsTEStI �� NALENo� 3/23/21 Michael Staten,P.E. Geotechnical Engineer Envirotech Engineering Geotechnical Report Addendum#1 PO Box 984 Page 1 of 1 Knudsen Tracts Single Family Residences Belfair,Washington 98528 Parcel 12220-33-00250 Ph. 360-275-9374 March 23,2021