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Home My WebLink AboutGEO2021-00087 A&B FPA2021-00014 Lots1,2,4 - GEO General - 11/12/2021 Gco GEOTECHNICAL REPORT FOR LOGGING NW GREEN PROPERTY LOTS 1 & 2 PART OF TRl OF SW NE & SE NW Ex ST R/W ALLYN, WASHINGTON PREPARED FOR NW GREEN CONSTRUCTION INC. BY ALL AMERICAN GEOTECHNICAL OLYMPIA, WASHINGTON NOVEMBER 12, 2021 ALL AMERICAN GEOTECHNICAL CONTACT INFORMATION PREPARER INFORMATION AAG PROJECT NUMBER: AAG21-144 CONTACT: CURTIS D.CUSHMAN ADDRESS: 8947 BUTTONWOOD LANE NE OLYMPIA,WASHINGTON 98516 TELEPHONE: (360)491-5155 CELL: (360)481-6677 EMAIL ADDRESS: CURTIS.CUSHMAN@COMCAST.NET CLIENT INFORMATION CLIENT: NW GREEN CONSTRUCTION TELEPHONE: 360-269-6049 BILLING ADDRESS: NW GREEN CONSTRUCTION 261 HAMILTON ROAD N CHEHALIS,WA 98532 SITE ADDRESS: STATE ROUTE 3 AT E HOMESTEAD DRIVE TRIOFSWNE&SE NW EXSTR/w ALLYN,WASHINGTON EMAIL DANIELSELF53@GMAIL.COM PARCEL NUMBER 12217-24-00010 GPS LOCATION: 47.399 -122.835 dd(between lots 1 &2) AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 2 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL ADDENDUM-2021 NW GREEN CONSTRUCTION INC. 261 HAMILTON ROAD N CHEHALIS,WASHINGTON 98532 RE: LOTS 1&2 TR1 OF SW NE&SE NW Ex ST R/W ALLYN,WASHINGTON 47.399 -122.835(between lots 1 &2) PARCEL 12217-24-00010 NOVEMBER 12,2021 Dear NW Green: NW Green Construction Inc. (client)hired All American Geotechnical, Inc. (AAG) in August of 2021 to prepare a geotechnical report for the above-named property located off WA SR-3 at E Homestead Drive north of Allyn, Washington. The proposed development is to timber the lot and make it available for eventual development. The parcel noted above has been tentatively divided into 4 lots. This report deals with lots 1 &2 located on the northwest side of E Homestead Drive and extending to the western property line. The timbering is required for eventual development but the type of development and any design elements for development are not addressed in this report. Because of steep slopes along a natural drainage roughly between the two lots,a geotechnical report is required. This report will address the two conjoined lots and will be submitted with the Mason County checklist. There will be no timbering of the Landslide Hazard Areas (LHA)described in this text and on Figure 2 in the appendix. The intent of this project is to timber the areas on the two lots is to harvest the timber and to provide room for future development. Harvesting will be done under the conditions and requirements of the logging permit. As per client request, we have conducted a soils exploration and slope stability analysis for the above- mentioned lots. The results of this investigation, together with our recommendations, are to be found in the following report. This report and the checklist will be sent by PDF to the client. Site geology was looked at in various locations. The site has a specific geological type that will be detailed in the text. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 3 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL We appreciate this opportunity to be of service to you and we look forward to working with you in the future. If you have any questions concerning the above items,the procedures used, or if we can be of any further assistance,please call us at the phone number listed below. Respectfully Submitted, ALL AMERICAN GEOTECHNICAL,INC. Curtis D. Cushman, L.G., L.E.G. Senior Engineering Geologist AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 4 Phone#: (360)491-5155 Cell#:(360)481-6677 ALL AMERICAN GEOTECHNICAL We appreciate this opportunity to be of service to you and we look forward to working with you in the future. If you have any questions concerning the above items,the procedures used,or if we can be of any further assistance,please call us at the phone number listed below. Respectfully Submitted, ALL AMERICAN GEOTECHNICAL,INC. of Wash�� /lz 20%1 engineed ce Curtis D. Cushman,L.G.,L.E.G. 2439 �`°`J15`.�g� Senior Engineering Geologist e'/sed GPe Curtis Dean Cushman AAG21-144 8947 Buttonwood Lane NE,Olympia, WA 98516 4 Phone#:(360)491-5155 Cell#:(360)481-6677 ALL AMERICAN GEOTECHNICAL TABLE OF CONTENTS CONTACT INFORMATION 2 INTRODUCTION 7 1) SITE CONDITIONS 8 SURFACE CONDITIONS 8 1)(A)SITE GEOLOGY 9 1)(B)SOIL TYPES 10 1)(C)GROUND WATER CONDITIONS 12 1)(D)UPSLOPE GEOMORPHOLOGY 12 1)(E)UPSLOPE WATERBODIES AND WETLANDS 12 1)(F) LANDSLIDE ACTIVITY 12 2) SITE PLAN 12 3) EXPLORATORY HOLES OR PROBES 12 4) PROPOSED DEVELOPMENT 13 5) CROSS SECTION 13 6) SLOPE STABILTY ANALYSIS 13 LIQUEFACTION AND SITE CLASS 14 GEOSEISMIC SETTING 14 LATERAL EARTH PRESSURES 15 7) RESTRICTIONS 15 A) PLACEMENT OF DRAINAGE FEATURES 15 B) PLACEMENT OF SEPTIC DRAIN FIELDS 15 C) PLACEMENT OF COMPACTED FILLS 15 D) BUFFERS 16 E) SETBACKS 16 8) CLEARING AND GRADING PLAN 16 9) EROSION CONTROL PLAN 17 10) ON AND OFFSITE IMPACTS 17 11) FINAL DEVELOPMENT CONDITIONS 17 12) STRUCTURAL MITIGATION 17 13) SITE PLAN 17 CONCLUSIONS AND RECOMMENDATIONS 18 PROVISIONS 18 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 18 READ THESE PROVISIONS CLOSELY 18 REFERENCES 19 AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 5 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL APPENDIX 21 2015 IBC DESIGN SPECIFICATIONS 22 SLOPE MODELS 24 STATIC MODEL A-A'LINE 24 DYNAMIC MODEL A-A'LINE 25 STATIC MODEL B-B'LINE 26 DYNAMIC MODEL B-B'LINE 27 FIGURES 28 FIGURE 1.VICINITY MAP 28 FIGURE 2.SITE PLAN 29 FIGURE 3. EROSION CONTROL NOTES 30 AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 6 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL INTRODUCTION This report addendum summarizes the results of our geotechnical consulting services for the timbering of two conjoined lots on part of the parcel herein described. The lots are on the northwestern side of E Homestead Drive which comes off State Route 3 north of Allyn,Washington. The lots are approximately 19.3 direct air-miles northeast of downtown Shelton,Washington. The location of the site is shown relative to the surrounding area on the Vicinity Map,Figure 1. The lots are located on a larger parcel which,overall,is on a glacially-formed plateau cut be a large drainage that descends eastward to eventually arrive at North Bay, the deepest part of Case Inlet. The lots are undeveloped with limited road access off E Homestead Drive. The geology is Vashon till and advance outwash as described in"Geology,"below. Our understanding of the project is based on our discussions with the client and their agents. In general, there will be no grading and the only disturbance of the soil will be creating logging-grade access roads. The approximate layout of the site is shown on the Site Plan,Figure 2. The purpose of our services is to evaluate the surface and subsurface conditions at the site in order to satisfy the requirements of the Mason County Critical Areas Ordinance,and as a basis for providing geotechnical recommendations for the project. All American Geotechnical is therefore providing geologic and hydrogeologic services for the project. Specifically, our scope of services for this project includes the following: 1. A review of the available geologic,hydrogeological and geotechnical data for the site area. 2. A geologic reconnaissance of the site area and surrounding vicinity. 3. Investigation and identification of shallow subsurface conditions at the site by characterizing the exposed soil,reviewing published well logs, and sampling. 4. Comparison of site to published geologic maps,previous field investigations,and open file reports. Inspection of aerial photos is used to determine the geomorphology of the site. 5. Evaluation of the landslide, erosion, and seismic hazards at the site per the Mason County Critical Areas Ordinance regulations(as of 2019). 6. Dynamic and static slope stability modeling. 7. Geotechnical recommendations for fill placement, drainage, and typical erosion control measures(Figure 3). The most critical slopes are on the side of the drainage which divides the two lots. They exceed 40% and are greater in height than 10 feet. Therefore,Mason County requires that a geotechnical report be prepared in accordance with the Critical Areas Ordinance. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 7 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AwRICAN GGEOTECHNICAL 1) SITE CONDITIONS SURFACE CONDITIONS Lot 1 is an irregular hexagon long to the east-west and tapering somewhat toward the west.Lot 2 is a highly irregular polygon conjoint with Lot 1 and extending to the west to the property line there. It has direct access from E Homestead Drive as does Lot 1. Lot 1 was surveyed by Turnbow Land Surveying and has an area of 6.98 acres. Lot 2 was surveyed by the same company and has an area of 12.15 acres. The tops of the Landslide Hazard Areas(LHA)on both lots are well defined and will not be difficult to see when harvesting the timber. For obvious reasons,there are no 50-foot vegetation buffers drawn on Figure 2. The lots are located at the entrance to the Lakeland Village development. Topographically, Lot 1 is rather restricted in size,with the plateau that forms its top sloping in a regular fashion to the east just north of the drainage. To the contrary,the larger Lot 2,while also descending to the east overall south of the drainage, has a wide flat area in the center of the lot interrupting the descending slope. Both have sufficient room for future development. There are only a few residences in the immediate area of Lots 1 and 2. a-site exposure is to the east. Site elevations for the two lots is approximately 205 feet near the turnoff of E Homestead Drive to near 380 feet at the northwest corner. The site was visited by Curtis D Cushman L.E.G. and Blaise Jelinek, E.I.T of All American Geotechnical on August 25,2021. The purpose of a site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. A site map was prepared identifying features of the property based on the Tumbow survey. Surficial exploration and sampling were performed. Sampling provides representative material for evaluation. Visual observations were documented. Site-specific features were mapped. Timbering is proposed for these two lots in conformance with the applicable timbering permit. At the time of the site visit, active erosion was not observed on the parts of the lots that were accessible. No evidence of deep-seated slope instability was observed on site. Trees located on the property in general and in the immediate vicinity are seen to be predominately straight and vertical. There is no standing water of any form and no springs. There are no streams but the drainage was carved by stream erosion, likely seasonal. There is no other evidence of surface water or even of local natural drainage channels. The general topography of the site indicates that drainage flows overall to the east and locally to the southeast. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 g Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL The LiDAR map to the right shows no f landslides at or the client property. To ✓` ,*` the north is a large mapped area that is apparently an old landslide deposit. A ;_ . `+' crescent scarp faces to the northeast -� r with Highway 3 and Old Highway 3 ,, crossing the debris below it. South of the roads, the ,topography of the f °� landslide debris is smooth while north of the roads it appears fresher, with apparent "hummocky terrain." This material is now cut by numerous branches of a small dendritic stream that flows to the east. This overall is at least 300 feet from the lots to be timbered and the failure appears stable at this time. 1)(A)SITE GEOLOGY The site is situated within the Puget Sound glacial province. The existing topography, as well as the surficial and shallow subsurface soils in the area, is the result of the most recent Vashon Stade (stage) of the Fraser glaciation that occurred between about 9,000 and 11,000 years ago, and weathering and erosion that has occurred since. A description of the surficial soils is included in the"Site Soils,"below. In general, the soil units are derived directly from the underlying Vashon till to be described,below. The Geologic Map of the Belfair 7.5-minute Quadrangle Mason, Kitsap, and Pierce Counties, Washington Open File Report 2009-7 by Polenz,M. and others through the Washington Division of Geology and Earth Resources is the primary source for the following,taken from The Mason County GIS: Qgt(Vashon till) Geologic Unit Symbol: Qgt Geologic Unit Age: Pleistocene Geologic Unit Name: Vashon Stade till Publication Source: WGS Publication Number: OFR 2009-7 Quadrangle Name: Belfair Unit Description: Unsorted, unstratified(but locally banded)mix of clay, silt, sand, and gravel; typically supported by a sandy matrix;mostly gray but locally ranging to tan, light brown, or orange; typically unweathered; lodgment till compact, with well-developed facies resembling concrete, but near the surface commonly hackly and(or) looser and covered by 1 to 6 ft of loose ablation till; deposited AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 9 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL directly by glacial ice and commonly includes clasts or clumps plucked from underlying units. Clasts are commonly striated and faceted, with angular or rounded edges... Age: Pleistocene Lithology: continental glacial till Age-Lithology: Pleistocene continental glacial till This will be the general geology as seen in the field and on the mapping. However, the access to the till is through a well-exposed section of the following: Qga(Vashon Stade advance outwash) Geologic Unit Symbol: Qga Geologic Unit Age: Pleistocene Geologic Unit Name: Vashon Stade advance outwash Publication Source: WGS Publication Number: OFR 2009-7 Quadrangle Name: Belfair Unit Description: Pebble to cobble gravel, sand, and layers and lenses of silt and clay;gray to tan; typically stratified, well rounded, well sorted, and clean (<S percent silt or clay in matrix), except in less- sorted and more angular ice proximal deposits.... Age: Pleistocene Lithology: continental glacial drift Age-Lithology: Pleistocene continental glacial drift This unit is seen here as dominantly sand, which, while compact where undisturbed, is easily loosened by cutting with a bulldozer blade. The Lakeland Village water well is the only one that is reasonably located and which is near the lots. It is a mixed column with gravels and sand and with some clay. This is in keeping with the Qgt over Qga seen in the field. Water is unlikely to be encountered in timbering or developing these lots. The Qgt Vashon till is ubiquitous to the region and is suitable for support of heavy equipment. The material encountered was SP—Poorly graded sand and likely GP, Poorly graded sandy gravel (ASTM classification). 1)(B)SOIL TYPES BUILDING SITE SOIL The USDA Web Soil Survey has mapped the site soil entirely as Alderwood gravelly sandy loam with the Ab soil predominant over the two parcels. This soil is described as follows: Ab—Alderwood gravelly sandy loam, 8 to 15 percent slopes Map Unit Setting AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 10 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL • National map unit symbol: 2t626 • Elevation: 50 to 800 feet • Mean annual precipitation: 20 to 60 inches • Mean annual air temperature: 46 to 52 degrees F • Frost-free period: 160 to 240 days Map Unit Composition • Alderwood and similar soils: 85 percent • Minor components: 15 percent Description of Alderwood Setting • Landform: Hills, ridges • Landform position (two-dimensional): Shoulder • Landform position (three-dimensional): Nose slope, talf • Down-slope shape: Convex, linear • Across-slope shape: Convex • Parent material: Glacial drift and/or glacial outwash over dense glaciomarine deposits Typical profile • A - 0 to 7 inches: gravelly sandy loam • Bw1 - 7 to 21 inches: very gravelly sandy loam • Bw2 - 21 to 30 inches: very gravelly sandy loam • Bg - 30 to 35 inches: very gravelly sandy loam • 2Cd1 - 35 to 43 inches: very gravelly sandy loam • 2Cd2 - 43 to 59 inches: very gravelly sandy loam • Properties and qualities • Slope: 8 to 15 percent • Depth to restrictive feature: 20 to 39 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 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water supply, 0 to 60 inches: Very low (about 2.7 inches) There is some Ac Alderwood at the eastern end of Lot 1 which has 15 to 30% slopes but is otherwise the same as the above. The Alderwood is sourced on glacial outwash as well as on till,but here,the soil would likely be more representative of a till origin rather than the sandy Qga outwash seen on-site. EROSION HAZARD CLASSIFICATION The purpose of the Erosion Hazard Section is to identify areas that present potential dangers to public health and safety, and to prevent the acceleration of natural geological hazards, and to neutralize the risk to the property owner from development activities. AAG21-144 8947 Buttonwood Lane NE, Olympia, WA 98516 11 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL Areas in Mason County underlain by soils, which are subject to severe erosion when disturbed. Such soils include, but are not limited to,those for which potential for erosion is identified in the Soil Survey of Mason County,USDA Soil Conservation Service, 1960, or any subsequent revisions or additions to this source. These soils include, but are not limited to, any occurrence of River Wash ('Ra') or Coastal Beaches ("Cg') and the following when they occur on slopes 15%or steeper: a. Alderwood gravelly sandy loam ("Ac"and "Ad') b. Cloquallum silt loam ("Cd') c. Harstine gravelly sandy loam ("Hb') d. Kitsap silt loam ("Kc') The Alderwood Ab(5 to 15%slope)is not mentioned in the Soil Survey as having severe erosion potential. The steeper Ac(15 to 30%)is mentioned as having erosion potential if not controlled. Logging operations rarely exceed denudation of 5%, and most of it shall be on the lesser slopes of the Alderwood Ab. Proper care should avoid erosion hazards. 1)(C)GROUND WATER CONDITIONS No surface water flow was observed on site. There was no evidence of springs on the slopes. 1)(D)UPSLOPE GEOMORPHOLOGY GrGkln(/+ Just to the west of the parcels, the topography apexes at the approximately 390 foot height. The steepest slope measured on the GIS leading up to these heights was in the area of 25%. This does not represent a problem for the timbering operations nor for future development. 1)(E)UPSLOPE WATERBODIES AND WETLANDS There are none. 1)(F) LANDSLIDE ACTIVITY The only landslide in the area is the large but apparently complete one beginning over 300 feet to the north. There are no other landslides mapped in the area and there are none evident on LiDAR. There is no evidence of landslide activity at the lots anecdotally, seen on site, or on LiDAR. 2) SITE PLAN The location of the lots and their topography is shown on Figure 2. The LHAs are shown along with the geology and soil types. There are no plans for development at this time,so there is no residential footprints, access roads, and no septic drainfields shown. 3) EXPLORATORY HOLES OR PROBES The geologic column is well exposed in exposures on-site and in recent road-cuts. The soil tested on-site is firm and unyielding. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 12 Phone#: (360)491-5155 Cell#: (360)481-6677 t ALL AMERICAN GEOTECHNICAL 4) PROPOSED DEVELOPMENT Figure 2 shows the general lay-out. Setbacks for logging will be discussed below. 5) CROSS SECTION Four cross-sections along line A—A' and line B—B' are in the Appendix. 6) SLOPE STABILTY ANALYSIS Factors of safety were determined using the Bishop (semi-circular) method. The site was modeled monolithically with information from the volcanic unit described in the literature and as seen on-site. The parameters used in this modeling were based on experience with the surroundings and the types of materials encountered on site. A continuous load of 2500-lb per foot was placed across the top of the landslide hazard area. No groundwater was included in the model,based upon neighboring well logs and the stream base. Slope stability was modeled using the GALENA 6.1 program in both static and dynamic conditions (ca= 0.15,per Mason County Code). "Static" condition refers to an"as is"state of a given slope. "Dynamic" puts seismic acceleration into the model for earthquake conditions. The factor for ground acceleration(ca) was determined from the Peak Ground Acceleration from the USGS Seismic Design Maps,included in the Appendix. There were no deposits on site. The model is used here to approximate massive basalt outcrop. The site was modeled with the Qgt overlying Qga modeling units. The unit was modeled using the following parameters presented in Table 1. Geologic Modeling Values. Table 1. Geologic Modeling Values Geologic Unit I'nit Weiuht Cohesion Phi Angle Qgt-Vashon Stade till 1 � 400 41 t Qga-Pre-Vashon Glacial Advance 11 4; 100 36 Six analyses were calculated along the two cross-sections,itemized on Table 2.Modeling Parameters and Findings The Analysis Number corresponds to the output presented on pages 24-27 The slopes were modeled based upon observations, field measurements, and available mapping. Initial positions were selected based upon the placement of the structure and the shape of the slopes. The initial points were varied over the analysis range indicated; with 50 different positions tested across these ranges. A total of 125,001 calculations were performed for Analysis 1 through 4. Calculated Factors of Safety are presented in Table 2. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 13 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL Table 2. Modeling Parameters and Findings Analysis Load Across Analysis Earthquake Slope to I Initial Positions(Analysis Range) Configurations Factor of Number Building Envelope Type Force Load Lo«er i pper Radius Analyzed Safety Cross-Section A.A' Analysis 1 ... 2500#125--145' 1Static 1 0.0 _ ;Below 150(20) _ 1125(40) t90(40 3 125,001 T 1.6_8 r.._....._..........T......._..._....... r _�.._...._. ..... .. Analysis 2 1 2500#125-145' ;Dynamic. ,0.150 _;Below _DSO(20)� 125(40) 90(40�_ 125001 1.31� Cross-Section B-B' ....._....... Analysis 3 r_ 2500#195-215' Static _ _ 0.01 ;Below T 1115(550) 1195 L4OZ_ 180(30) 125_001 2.00 -- Analysis 4 ; 2500#195 215' .Dynamic! 0.150 g iBelow 115(50) {195(40) 80(i0) 125,001 1.55 Under static conditions,the slopes generally did not show susceptibility to deep-seated failure that would cause damage to the proposed residence. Under dynamic loading (Ca=0.15), the computations demonstrated that the slopes are safe with respect to the modeled areas. These calculated Factors of Safety meet the requirements set forth by Mason County that is, 1.50 for static and 1.1 for dynamic loading scenarios. Based on our slope models representing critical slopes at the subject sites, it is apparent that the logging sites are not susceptible to damage by deep-seated movements or instability. LIQUEFACTION AND SITE CLASS The Liquefaction Susceptibility Map of Mason County, Washington by Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann(September 2004)maps the site area as having being Very Low. The Site Class Map of Mason County, Washington by Palmer,Magsino,Bilderback, Poelstra,Folger, and Niggemann(September 2004)maps the site area as site class C. Site class B is Very Dense Soil, Soft Rock. GEOSEISMIC SETTING According to the Seismic Zone Map of the United States (Figure 1613.3.1(1)) contained in the 2015 International Building Code (IBC), the project site is located where the maximum spectral response acceleration is 55 percent of gravity (g). Site-specific seismic parameters are presented on the "Seismic Design Summary"in the Appendix of this report. We recommend following seismic factors for design purposes. • Site Class: C (soft rock) • Spectral response acceleration, short period(SMs): 1.422g(Fa= 1.0) • Spectral response acceleration, 1-second period(Smi): 0.74lg(Fv= 1.3) • Peak Ground Acceleration(PGA) 0.589g AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 14 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL LATERAL EARTH PRESSURES Lateral loads may be resisted by friction on the bases of footings and floor slabs and as passive pressure on the sides of footings. An allowable coefficient of friction of 0.40 may be used to calculate friction between the concrete and the underlying native soil. We recommend the following be used to determine the lateral earth pressures considering the onsite SP or GP • �(soil friction angle) 36 degrees • Ko (at rest earth pressure coefficient) 0.412 • Ka(active earth pressure coefficient) 0.259 • Kp(passive earth pressure coefficient) 3.85 • y(soil unit weight) 125 pcf 7) RESTRICTIONS A) PLACEMENT OF DRAINAGE FEATURES There are no drainage features as there are no developmental plans at this time. No surface water and no storm discharge of any sort should be directed toward the steep slopes. B) PLACEMENT OF SEPTIC DRAIN FIELDS There are no plans to develop and hence no septic plans. C) PLACEMENT OF COMPACTED FILLS RECOMMENDATIONS FOR SITE PREPARATION There are few limitations on timber development and these are commonly in the timbering permit. All roads should be placed so there is little chance of downslope erosion in keeping with general practices common in the industry. As there are no plans to cut on the LHA slopes, silt fences will not be needed if -k care is taken to keep storm water from attacking any areas of reduced vegetation or denudation by the logging. Material on site may be suitable for structural fill. Where placement of fill material is required, the exposed subgrade areas should be compacted to a firm and unyielding surface prior to placement of any fill. Over-excavation in any building area should be backfilled with structural fill, compacted to the density requirements described in the "Structural Fill" section of this report. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 15 Phone#:(360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL If structural fill is needed, we recommend that a member of our staff evaluate the exposed subgrade conditions RECOMMENDATIONS FOR STRUCTURAL FILL Fill for this site would be native or import. All fill material should be placed as structural fill. In general, the structural fill should be placed in horizontal lifts of 8 inches to allow adequate and uniform compaction of each lift. Fill should be compacted to at least 95 percent of MDD(maximum dry density as determined in accordance with ASTM D-1557)to grade. The final appropriate lift thickness will depend on the fill characteristics and compaction equipment used. We recommend that our field representative evaluate the appropriate lift thickness during construction. Material placed for structural fill should be free of debris,organic matter,trash,and cobbles greater than 6 inches in diameter. The moisture content of the fill material should be adjusted as necessary for proper compaction. RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS As FILL Onsite soils may be considered for use as structural fill only if industry standards are satisfied. Fill material requirements are found on page 9-26 to 9-30 of the WSDOT Standard Specifications 2010. In general, a native soil (sand, silt, and gravel) encountered on a site must have less than 10 percent fines (material passing the US No. 200 sieve)to be suitable for use as structural fill. D) BUFFERS There are no vegetation buffers mapped on Figure 2. The object of this report is to evaluate a timbering operation and not the vegetation buffers of a residential development. E) SETBACKS No geotechnical setback is required but equipment should be set back at least 10 feet. All other setbacks are to be observed. 8) CLEARING AND GRADING PLAN There will be clearing as this is a logging operation. There may be grading, but there will be noy roads going over the LHA, so standard procedures for logging operations may be allowed for this site. "No Disturb"zones will not be required. There will be no removal of vegetation in the LHA. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 16 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL If structural fill is needed, we recommend that a member of our staff evaluate the exposed subgrade conditions RECOMMENDATIONS FOR STRUCTURAL FILL Fill for this site would be native or import. All fill material should be placed as structural fill. In general, the structural fill should be placed in horizontal lifts of 8 inches to allow adequate and uniform compaction of each lift. Fill should be compacted to at least'95 percent of MDD(maximum dry density as determined in accordance with ASTM D-1557)to grade. The final appropriate lift thickness will depend on the fill characteristics and compaction equipment used. We recommend that our field representative evaluate the appropriate lift thickness during construction. Material placed for structural fill should be free of debris,organic matter,trash,and cobbles greater than 6 inches in diameter. The moisture content of the fill material should be adjusted as necessary for proper compaction. RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL Onsite soils may be considered for use as structural fill only if industry standards are satisfied. Fill material requirements are found on page 9-26 to 9-30 of the WSDOT Standard Specifications 2010. In general, a native soil (sand, silt, and gravel) encountered on a site must have less than 10 percent fines (material passing the US No.200 sieve)to be suitable for use as structural fill. D) BUFFERS There are no vegetation buffers mapped on Figure 2. The object of this report is to evaluate a timbering , operation and not the vegetation buffers of a residential development. E) SETBACKS No geotechnical setback is required but equipment should be set back at least 10 feet. All other setbacks are to be observed. 8) CLEARING AND GRADING PLAN There will be clearing as this is a logging operation. There may be grading, but there will be no roads going over the LHA, so standard procedures for logging operations may be allowed for this site. "No Disturb"zones will not be required. There will be no removal of vegetation in the LHA. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 16 Phone#:(360)491-5155 Cell#:(360)481-6677 ALL AMERICAN GEOTECHNICAL r- 9) EROSION CONTROL PLAN It is our opinion that the potential erosion hazard of the site is not a limiting factor for the proposed developments. Revegetation as needed should occur immediately following timbering. Temporary and permanent erosion control measures should be implemented and maintained during construction and/or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential receiving waters. Erosion control measures may include, but not be limited to, silt fences, berms, and swales with ground cover/protection in exposed areas. No re-contouring of the site will occur. We do not believe extensive erosion control will be needed as most of the timbering is on low slopes and potential water erosion may be readily managed. Areas that are fully denuded of vegetation will require covering and possibly reseeding if necessary to prevent erosion. Otherwise,the understory will quickly and readily re-establish itself in protecting the slopes. Straw, hay, or jute matting shall be used to cover exposed soils until permanent vegetation is established. A revegetation plan is not be required. Please see the erosion notes on Figure 3. This shows the recommended development of a silt fence (and also generic notes on drainage tightlines which are not applicable to this report). Again,this is not recommended unless the work has denuded a slope. 10) ON AND OFFSITE IMPACTS There should be no notable on- or offsite impacts if the project is completed according to the recommendations of this report and in accordance with all regulations and to the highest standards and practices of the logging firm. 11) FINAL DEVELOPMENT CONDITIONS The lots are not ready for final development. Following the timbering,the lots will be developed depending on the client's timetable. The site must be left in a state that will not create erosion conditions and/or excessively increase water flow. Eventually, the development will follow all guidelines and regulations and will be geotechnically reviewed prior to permitting for construction. 12) STRUCTURAL MITIGATION There is none. 13) SITE PLAN Please see Figure 2. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 17 Phone#:(360)491-5155 Cell#:(360)481-6677 ALL AMERICAN GEOTECHNICAL 9) EROSION CONTROL PLAN It is our opinion that the potential erosion hazard of the site is not a limiting factor for the proposed developments. Revegetation as needed should occur immediately following timbering. Temporary and permanent erosion control measures should be implemented and maintained during construction and/or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential receiving waters. Erosion control measures may include, but not be limited to, silt fences, berms, and swales with ground cover/protection in exposed areas. No re-contouring of the site will occur. We do not believe extensive erosion control will be needed as most of the timbering is on low slopes and potential water erosion may be readily managed. Ares that are fully denuded of vegetation will require covering and possibly reseedin if necessary to prevent erosion. Otherwise, the understory will quickly an rea i y re-estab is Its in protecting the slopes. Straw, hay, or jute matting shall be used to cover exposed soils until permanent vegetation is established. A revegetation plan is not be required. Please see the erosion notes on Figure 3. This shows the recommended development of a silt fence (and also generic notes on drainage tightlines which are not applicable to this report). Again,this is not recommended unless the work has denuded a slope. 10) ON AND OFFSITE IMPACTS There should be no notable on- or offsite impacts if the project is completed according to the recommendations of this report and in accordance with all regulations and to the highest standards and practices of the logging firm. 11) FINAL DEVELOPMENT CONDITIONS The lots are not ready for final development. Following the timbering,the lots will be developed depending on the client's timetable. The site must be left in a state that will not create erosion conditions and/or excessively increase water flow. Eventually, the development will follow all guidelines and regulations and will be geotechnically reviewed prior to permitting for construction. 12) STRUCTURAL MITIGATION There is none. 13) SITE PLAN Please see Figure 2. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 17 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL CONCLUSIONS AND RECOMMENDATIONS Based on the results of our site investigation, subsurface observations, and our experience in the area, it is our opinion that the site is suitable for the proposed timbering project. If properly done to standard practices, the lots appear suitable for the work and the work will not create erosion hazards. Proper drainage control measures will reduce or eliminate the potential for erosion in this area. Revegetation should be done as per recommendations in the text,above. PROVISIONS We have prepared this report for the exclusive use of Northwest Green Construction, Inc. and their authorized agents for the two conjoined lots of E Homestead Drive in Mason County, Washington. Site inspections, research, and mapping have culminated in this report. This report is intended to meet the requirements of the Mason County Critical Areas Ordinance. This report does not specify setbacks for: line-of-sight setbacks, FWHCA setbacks, eagle tree setbacks, wetland setbacks, or property line setbacks. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, expressed or implied, should be understood. Clients and property owners must understand that,despite any calculated Factors of Safety,surficial failure and landslides can and do occur on steep slopes. The property owner should monitor the stability of the site following timbering. Moreover, acceptable Factors of Safety do not guarantee there cannot be failures. It is the responsibility of the property owner to understand that there are always risks in developing on or near steeply sloped areas. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to onsite personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals, and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments,claims and disputes.All American Geotechnical includes these explanatory"limitations" provisions in our reports to help reduce such risks. The equipment,techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, geotechnical engineering or geologic reporting does not usually relate any environmental findings, conclusions or AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 18 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. REFERENCES MAPS DeLorme 3-1)TopoQuads(2002),Source Data USGS,Yarmouth,Maine. Dragovich,Logan,Walsh,and Schasse(2002), Geological Map of Washington—Northwest Quadrant(Geological Map GM- 50),published by Washington State Department of Natural Resources. Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann (September 2004), The Liquefaction Susceptibility Map of Mason County, Washington,published by Washington State Department of Natural Resources. Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004), The Site Class Map of Mason County, Washington,published by Washington State Department of Natural Resources. Rogers,A.M.,Walsh,T.J.,Kockelman,W.J.,and Priest,G.R.(1996),Map showing known or suspected faults with quaternary displacement in the Pacific Northwest,published by U.S.Geological Survey OFR 91-441-0,Plate 1,scale 1:2,000,000. Smith,Carson(1977),Relative Slope Stability of the Southern Hood Canal Area, Washington,prepared in cooperation with the Washington Department of Natural Resources Division of Geology and Earth Resources; and, Department of the Interior United States Geological Survey. PUBLICATIONS ASTM International(2005),Annual Book of Standards 2005, Section 4, Volume 4.08,published by ASTM International,West Conshohocken,Pennsylvania. International Code Council,Inc.(2006),2006 International Building Code,published by International Code Council,Inc. Kollmorgen Instruments Corporation(1994),Munsell Soil Color Charts(1994 Revised Edition),published by Macbeth Division of Kollmorgen Instruments Corporation,New Windsor,New York. Ness,Fowler,Parvin(1960),The Soil Survey of Mason County, Washington, USDA Soil Conservation Service,in cooperation with the United States Department of Agriculture,and Washington Agricultural Experimental Station, and the Soils Conservation Service. Parks, Neal, Koloski, Laprade, Molinari, Butler, and Lorentson (November 2006), Guidelines for Preparing Engineering Geology Reports in Washington, published by Washington State Geologist Licensing Board,Olympia,Washington. Sowers(1979),Introductory Soil Mechanics and Foundations: Geotechnical Engineering,Macmillan Publishing Co.,Inc. AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 19 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL WEBSITES(ALSO ON MASON COUNTY GIS,WASHINGTON GEOLOGIC INFORMATION PORTAL,AND USDA WEB SOIL SURVEY) Mason County Government Information Services (http://www.co.mason.wa.us) Mason County Codes,Ordinances,and Regulations (http://www.co.mason.wa.us/code) Vegetation Management Guide for Puget Sound Bluff Property Owners (http://www.ecy.wa.gov/biblio/9331.html) United States Department of Agriculture Natural Resource Conservation Service (http://soildatamart.nres.usda.gov) Washington Administrative Code (http://apps.leg.wa.gov/warn Washington Department of Ecology (http://apps.ecy.wa.gov/welllog) (https:Hfortress.wa.gov/ecy/coastalatlas/viewer.htm) AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 20 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL APPENDIX USGS Seismic Design Specifications Slope Models Figure 1.Vicinity Map Figure 2. Site Plan Figure 3.Erosion Control Notes AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 21 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL 2015 IBC DESIGN SPECIFICATIONS OTCHazards by Location Search Information Redmond Coordinates: 47.398,-122.835 Seattle a 309 ft Elevation: 309 ft Renton Timestamp: 2021-11-10T18:55:04.939Z o Hazard Type: Seismic Tacoma` Q Reference IBC-2015 Document: Google Olympia Ma data m2021 Goo le Risk Category: III E ` p 9 Site Class: C MCER Horizontal Response Spectrum Design Horizontal Response Spectrum sa(g) Sa(g) 1.40 1.20 0.80 1.00 0.60 0.80 0.60 0.40 0.40 0.20 0.20 0.00 0.00 0 5 10 15 Period(a) 0 5 10 15 Period(s) Basic Parameters Name Value Description SS I A22 MCER ground motion(period=0.2s) Si 0.57 MCER ground motion(period=1.0s) SMS 1 A22 Site-modified spectral acceleration value SMi 0,741 Site-modified spectral acceleration value SDS 0.948 Numeric seismic design value at 0.2s SA SDI OA94 Numeric seismic design value at 1.Os SA Additional Information Name Value Description SDC D Seismic design category Fa 1 Site amplification factor at 0.2s F„ 1.3 Site amplification factor at 1.0s CRS 0.981 Coefficient of risk(0.2s) AAG21-144 8947 Buttonwood Lane NE,Olympia, WA 98516 22 Phone#: (360)491-5155 Cell#: (360) 481-6677 ALL AMERICAN GEOTECHNICAL Design Specifications Continued CR, 0.939 Coefficient of risk(1,0s) PGA 0.589 MCEIG peak ground acceleration FPGA 1 Site amplification factor at PGA PGA, 0,589 Site modified peak ground acceleration T, 16 Long-period transition period(s) SsRT 1.422 Probabilistic risk-targeted ground motion(0,2s) SsUH 1.45 Factored uniform-hazard spectral acceleration(2%probability of exceedance in 50 years) SsD 2,027 Factored deterministic acceleration value(0,2s) S1R'T 0.57 Probabilistic risk-targeted ground motion(1,0s) S1UH 0.608 Factored uniform-hazard spectral acceleration(2%probability of exceedance in 50 years) S1D 0.675 Factored deterministic acceleration value(1.0s) PGAd 0,726 Factored deterministic acceleration value(PGA) The results indicated here DO NOT reflect any state or local amendments to the values or any delineation lines made during the building code adoption process. Users should confirm any output obtained from this toot with the local Authority Having Jurisdiction before proceeding with design. Disclaimer Hazard loads are provided by the U,S.Geological Survey Seismic Design Web Services. While the information presented on this website is believed to be correct.ATC and its sponsors and contributors assume no responsibility or liability for its accuracy.The material presented in the report should not be used or relied upon for any specific application without competent examination and verification of its accuracy,suitability and applicability by engineers or other licensed professionals.ATC does not intend that the use of this information replace the sound judgment of such competent professionals,having experience and knowledge in the feld of practice,nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the report provided by this website. Users of the information from this website assume all liability arising from such use.Use of the output of this website does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site described by latituderlongitude location in the report. AAG21-144 8947 Buttonwood Lane NE, Olympia, WA 98516 23 Phone#: (360)491-5155 Cell#: (360) 481-6677 ALL AMERICAN GEOTECHNICAL SLOPE MODELS STATIC MODEL A—A'LINE F co > U 9 C 0 N R3 N Q � U m CD z R l o U cu ca u d� A, c Q 0 v 8 0 0 0 m E c � T O O ¢ 2 N - O a N Q O G o .Wd ¢ °` Q � z 0) ti AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 24 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERWAN GEOTECHNICAL DYNAmI MODEL A A LINE E } �05 k @ Iaa ® \ @ ■ _ ) / \ \ � � 10 ° 7 / co \ jiw $ t k � q k f & � ƒ { a % E ` \ ,C3 ° § k j \ c m R \ \ ( ) § § % � - AAG21-14 8947 Buttonwood Lane NE,Olympia,W*98516 25 Phone#: (360)49 13155 Cell+ (6)4 1-66 7 ALL AMERICAN GEOTECHNICAL STATIC MODEL B-B'LINE g � U o C N R e N m U 8 (O C LL Q 0 N N S N O O P 6] � Y C � a � v fi¢ F Q C N 9 Q G g 2 C.J J O 4 R AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 26 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL DYNAMIC MODEL B-B'LINE z 52 z' 5ca � 2 M z Lip LL .8 10 cc E 0- a- Q oz O fD O U2 3t 0 0 uj -i S2 CC 42) E --9 AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 27 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL FIGURES FIGURE 1.VICINITY MAP 122'59'00'W 122'52'00"W 122'51"00"W 122 'A, 0'lV WGS84 122°4900"V/ / Y i i r 1 Il� b 7 I' v '�•. �,�/ �i I. V b t � •� --..{ �1. • J' Pa 5 V�ctt,. Z ;f�1 Z ""�, uc t I s ff T—ws, - e / o / �� ' QQ �t z 1 G y 6� (. jai �t 122°53'00-W 122=52'00"W 122°51'00'W 122'50'00"W WGS84 122'49'00'W 0 5 I WE 14" 000 RE1 0__SOro W7D WTM rrac�Eso�lroPo�cooE�u�,Ec:oa>pecxa�.pc.�.lopo�l AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 28 Phone#: (360)491-5155 Cell#: (360)481-6677 NOTES Site Geology Site Soil This is not a survey. This map is a presentation of information from county,state,and federal Qgt—Vashon Slade till Ab—Aldenvood gravelly sand loam, agencies,client provided information,and onsite 8 to 15 percent slope. Qga—Vashon Slade advance outwash observations;for discussion purposes of the Ac—Aldrnvood gmvelly sand loam, report with which this map is included. Qgas--Vashon Slade advance ounvash sand 15 to 30 percent elope. \ 1 Af—Artitical Fill iMl \ 4 'v % : sa G ' ` o 3�0 Qga a cs+ i \ _ -- Af \ aao of Washy' Si ^ \ - b 1 Inch-120 Feet used Gem \ 0 60 120 240 Curtis Dean Cushman Contour Interal=5 feet All American Geotechnical,Inc. Project Drawn By: Site Plan permit Number. Parcel Number: 12217-24-00010 Figure 8947 Buttonwood Lane NE Number: BWJ Forest Practices Lots l&2 Olympia,Washington 98516 AAG21-144 11/10/2021 Allyn,WA Applicant Name: NW Green Construction Site Address: XXX-E Homestead Drive 2 FLIER FABRIC MATERIAL SIT WIDE ROLLS USE STAPLES OR WIRE RING TO ATTACH FABRIC TO W IRE 2*XrX14 GAUGE WIRE FABRIC OR EQUIVALENT GENERAL EROSION CONTROL NOTES: 7 1. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIORTO THE BEGINNING OF CONSTRUCTION.THE PROJECT ENGINEER AND THE COUNTY S� \ URFACE SHALL INSPECT AND APPROVE THE INSTALLATION OF 1/2 INCH MINIMUM DIAMETER STEEL ROD T\ EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUCTION. (STRAP)CLAMPED SECURELY TO PIPE ............... ........:.... 2.EROSION CONTROL MEASURES ARE NOT LIMITED TO THE ITEMS S•MAX ON THIS PLAN.THE CONTRACTOR IS RESPONSIBLE FOR THE CORRUGATED TIGHTLINE 4 INCH INSTALLATION AND MAINTAINANCE OF ALL EROSION CONTROL MEASURES, MINIMUM,6 INCH SUGGESTED NO SILTATION OF EXISTING OR PROPOSED DRAINAGE FACILITIES SHALL BE ALLOWED.CARE SHALL BE TAKEN TO PREVENT MIGRATION .±tom M/N/4r TX4•WOOD POSTS.STANDARD OR BURY BOTTOM OF FILTER L' UM SETrEROREOUALALTERNATE: MATERIAL IN B•X12•TRENCH OF SILTS TO OFF SITE PROPERTIES. 1pF �`+U''` �' SA, STEEL FENCE POSTS 3.THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL EROSION CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR ADDITIONS '''':�'-:.^":t':•'"�=`:''` "' TO THE EROSION CONTROL MEASURES.THE CONTRACTOR SHALL PROVIDE :�• ;::%?.;;:I-`rt�..-._ ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECESSARY "_` �;"•'=" b'%� BY THE COUNTY INSPECTOR AND/OR THE PROJECT ENGINEER.FAILURE FILTER FABRIC 8' TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL �+�'•.�� .^,5:;*Y 'A.�T'ti: +9�J"`•�^1{;. 7• REQUIREMENTS MAY RESULT IN CIVIL PENALTIES BEING LEVIED 2'X2'%14 GAUGE WIRE ..1r.!' ♦ •h.•L•Ry'!`•h• FABRIC OR EGUIVALENT AGAINST THE CONTRACTOR AND/OR PROJECT OWNER. ?✓ �^,� `.'` .'Ts.•::�i5 � ``4, i-0 p:•�ii..L.s!�. a:FV.SG�f :T�J'1 4.DURING THE WET SEASON NOVEMBER TO MARCH ALL DISTURBED SOILS ��>r" GROUND SURFACE 5'-0' SHALL BE STABILIZED WITHIN 48 HOURS AFTER STOP OF WORK.EROSION t•^'rr�'C;�k.?i• :�c"��.'q v *~� �f PROVIDE 1M•-1 ILL WASHED CONTROL MEASURES SHALL INCLUDE,BUT NOT IL LINKED TO, t'y`. •';,411.E:. ,��-} '?.hi'..`y�i GRAVEL BACKFlIDES OF NCH 1z COVERING THE SHEETING. STRAW REA MATING,JUTE SPOIL PILES WITHMOON EBOTH SIDES OF FILTER PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH. FENCE FABRIC ON THE SURFACE g•M OR WOOD CHIPS.SEEDING OF THE DISTURBED AREAS SHALL TAKE PLACE AS WEATHER PERMITS. TIGHTLINE ANCHORED WITH TWO, 7%4'WOOD POSTS 5.ALL SEEDED OR SODDED AREAS SHALL BE CHECKED REGULARLY 3 FOOT REBAR LENGTHS OR BOLTS. ALT:STEEL FENCE POSTS TO MAKE SURE VEGETATIVE COVERAGE IS COMLETE.AREAS SHALL BE REPAIRED,RESEEDED,AND FERTILIZED AS REQUIRED. FILTER FABRIC FENCE NOTES: 1.FILTER FABRIC SHALL BE PURCHASED W A CONTINUOUS ROLL CUT TO S.TRACKING OF SOIL OFFSITE WILL NOT BE ALLOWED.IF ANY SOIL IS THE LENGTH OF THE BARRIER TO AVOID USE OF JOINTS.WHEN JOINTS TRACKED ONTO A COUNTY STREET.IT SHALL BE REMOVED BY THE END ARE NECESSARY,FILTER CLOTH SHALL BE SPLICED TOGETHER ONLY AT OF THAT WORKING DAY.ANY FURTHER TRACKING OF MUD WILL THEN A SUPPORT POST WDH A MAXMUM&INCH OVERLAP AND SECURELY BE PREVENTED BY SWEEPING OR WASHING OF THE VEHICLES TIRES FASTENED AT BOTH ENDS TO THE POST. BEFORE DRIVING ON A COUNTY STREET. 2.POSTS SHALL BE SPACED A MAXIMUM OF 8 FEET APART AND DRIVEN 1.NO MORE THAN 500 LF OF TRENCH ON A DOWNSLOPE OF MORE THAN 5 SECURELY INTO THE GROUND(MINIMUM OF 30INCHES). PERCENT SHALL BE OPENED AT ONE TIME. 3.A TRENCH SHALL BE EXCAVATED APPROXIMATELY 8INCHES WIDE AND 12 INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER B.EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OF TRENCHES. jjFLARE END SECTION 9.TRENCH DEWATERING DEVICES SHALL BE DISCHARGED IN A MANNER THAT WILL QUARRY SPALL4.WHEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH i1 kH tiA NOT ADVERSELY AFFECT FLOWING STREAMS.DRAINAGE SYSTEMS OR OR ENERGY _a;V Nird, .:x;. •,.i.v�� SUPPOR FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE .4-�t i•i.. .F.!A A. OF THE POSTS USING HEAW DUTY WIRE STAPLES AT LEAST I INCH OFFSITE PROPERTIES. DISPERSION DEVICE ,F ASS {1p•;�y yy,y',t+y'•y'),',v_-.o;.�.y.'li`:A,4; i• LONG,TIE WIRES OR HOG RINGS.THE WIRE SHALL EXTEND IRO THE - -- TRENCH AMINIMUM OF 4 INCHES AND SHALL NOT EXTEND MORE THAN 38 10.ALL STORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJECT DURING INCHES ABOVE THE ORIGINAL GROUND SURFACE. CONSTRUCTION SHALL BE PROTECTED SO THAT SEDIMENT{ADEN WATER GRASS-LINED SWALE SHOULD BE A 5.THE STANDARD STRENGTH FILTER FABRIC SHALL BE STAPLED OR WIRED WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM. MINIMUM ONE FOOT WIDE AT THE TO THE FENCE AND 20 INCHES OF FABRIC SHALL BE EXTENDED 11.ALL OFFSITE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE BOTTOM AND ONE FOOT DEEP WITH IRO THE TRENCH.THE FABRIC SHALL NOT EXTEND MORE THAN 36 SHALL BE PROTECTED FROM SILTATION. A MAXIMUM SLOPE OF 5 PERCENT. INCHES STAR T THE LGNG TREEND S. FILTER FABRIC SMALL NOT BE STAPLED TO THE EXISTING TREES. MINIMUM 4 FEET 12.ALL DISTURBED AREAS SHALL BE SEEDED ES SODDED UPON COMPLETION LEVEL SECTION 6.WHEN THE WIRE E MESH S FILTER FABRIC AND CLOSER POST,IN SUCH IS OF WORK THE CONTRACTOR SHALL BE RESPONSIBLE TO ENSURE THAT USED.THE WIRE MESH SUPPORT FENCE MAP I E ELIMINATED,IN SUCH COMPLETE COVERAGE A THE DISTURBED AREAS IS PROVIDED 8 THAT ACASE,THE FILTER FABRIC IS STAPLED OROVEED DIRECTLY IN THE GROWTH OF THE VEGETATION IS ESTABLISHED. GEOTEXTILE FABRIC POSTS WITH ALL OTHER PROVISIONS OR ABOVE NOTES APPLYING. T.FILTER FABRIC FENCES SHALL NOT BE REMOVED BEFORE THE UPSLOPE 13.CATCH BASINS SHALL TRAP SEDIMENT OR FILTER FABRIC MUST BE AREA HAS BEEN PERMANENTLY STABILIZED. PLACED UNDER GRATE UNTIL VEGETATION IS ESTABLISHED. S.FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH RAINFALL AND AT LEAST DAILY DURING PROLONGED RAINFALL.ANY REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY. All American Geotechnical,Inc. Drawn By: BWJ Erosion Control Notes Permit Number: Parcel Number: 12217-24-00010 Olympia, Buttonwood Lane NE Figure 11/10/21 Forest Practices Olympia,Washington 98516 Allyn,Washington Applicant Name: N W Green Construction Site Address: XXX-E Homestead Drive T Revisions: yn � J 12/9/21, 11:46 AM Re:Geo-Report for NW Green Const Lots 1 &2 t Reply ® Delete Junk I v ••• X Re: Geo-Report for NW Green Const Lots 1 & 2 ASO Lc� 4' CURTIS CUSHMAN <curtis.cushman@comcast.net> t Reply Yesterday, 6:02 PM Michael MacSems Inbox Flag for follow up.Start by Thursday, December 09, 2021. Due by Thursday, December 09,2021. You replied on 12/9/2021 8:39 AM. Label: MasonCounty Q months) Expires:3/8/2022 6:02 PM Action Items Hello to you, Michael. I should have noted on all the reports (Lots 1 &2, 3, and 4), there were no close wells. The Village well, topographically lower or on the same elevation, hit water at -60 feet and that is its static level. I'm not sure of its location, either; the log has a P.O. Box on it. (Note that one log nearby has a well address in Gig Harbor.) I don't really like to use them unless they are solidly located. I think there will be no water encountered and I think the modeling is reasonable. The developers are aware that they'll need reports; I wrote all the reports only for the logging. I didn't see the clearing, but I don't get around too well, so I'll ask Blaise. Again, we did the survey for logging. If we're asked to do the development reports, we will do the geo in the light of where they wish to build. If it's too close to an LHA, we'll model it to get the setback. You may know from my previous reports that I am uneasy in crowding LHA slopes even with Factors of Safety that indicate they can be closer. Same here. As for the wells, how do you want me to write the above information? Yours truly, Curtis D Cushman --------------------------- Olympia,Washington On 12/08/2021 3:33 PM Michael MacSems <mms@masoncountywa.gov> wrote: https://owa.co.mason.wa.us/owa/projection.aspx 1/2 12/9/21, 11:46 AM Re:Geo-Report for NW Green Const Lots 1 &2 Reply ® Delete Junk I v ••• X I just read through your geo-report for Lot 1 and 2 for NW Green Construction (GEO 21-87-A). On checklist question 1.c, Ground Water conditions. Typically, this question is answered by estimating depth to ground water, usually by citing nearby well logs. Your answer talks about a lack of springs and seeps, which I think is an answer to a different question. Please go more in- depth (no pun intended) on the answer to this question. Other than that, the checklist looks okay. I do note that your geo-report is very clear that it only addresses logging and not eventual site development. As it happens, NW Green Construction has two permit applications in front of me, one for logging and the other for a large lot subdivision.The way Lot 1 is designed, there is no place on that proposed lot greater than 300' from the LHA, so that LLS application cannot be approved until a geo for site development has been prepared and approved. I will let the applicant know that. BTW, when you were on site did you notice that a building site had been cleared immediately next to the LHA on Lot 2? Thank you, Michael MacSems Subdivision, Forest Practices, Historic Preservation https://owa.co.mason.wa.us/owa/projection.aspx 2/2 GEO 7 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: U V Z th v '1��` (C.V S4 Permit#: )YA 7 1 - i 4 Parcel Date(s) of the Document(s) reviewed: 1 Z/ h / 2 1. (a) A discussion of general geologic conditions in the vicinity of the proposed development, OK? V Comment: (b) A discussion of specific soil types OK?)_Comment: U ) Z 7 (c) A discussion of ground water conditio s OK? ✓ Comment: 1 Z Qalckto M a K4 6 (d) A discussion of the upslope geomorphology OK? ✓ Comment: (e) A discussion of the location of upland waterbodies and wetlands OK? 1� Comment: J� 1 2- (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records OK? V Comment: ,j" 1 L 2. A site plan that identifies the important development and geologic features. OK? / Comment: t ' 2 3. Locations and logs of exploratory holes or probes. OK? Comment: M Se64 rcJ_-�j C 4. The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides, and toe) on a geologic map of the site. OK? ✓ Comment: Z 5. A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details of proposed grade changes. OK? 11 Comment: P Ylc k,C13 I - T 6. A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic safety factor is 1.1 and the quasi-static analysis coeffients should be a value of 0.15. OK?_ V Comment: (Y_ Y 7. (a) Appropriate restrictions on placement of drainage features OK? v Comment: �? 1 r — rUo► s: (b) Appropriate restrictions on placement of septic drain fields OK? V Comment: (f 1 /n1 Q �dldl�Pd�./ S 5 (c) Appropriate restrictions on placement of co cted fills and footings. OK? V Comment: S Page 1 of 2 Form Effective June 2008 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. OK? �Comment: (e) Recommended setbacks from the landslide hazard areas s reline bluffs and the tops of other slopes. OK? ✓ Comment: �' /6 0--� 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. l OK? ✓ Comment: / 9. Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, landslides and harmful construction methods. n OK? � Comment: 10. An analysis of both on-site and off-site impacts of the proposed development. OK? y Comment: tf 11. Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. 1 OK? Comment: I 12. Recommendations for the preparation of structural mitigation or details of other proposed mitigation. OK? 1/ Comment: L) 0�l CA_Q._- 13. A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of existing and proposed development on the site. OK? ✓ Comment: (j' 2— Are the Documents signed and stamped?__Y_ By whom? C(,,Y 1 L4 cl'I n4CC License#: Z -� License type: La c'e wccj G�- ,.;.- FIRST REVIEW ❑ Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by , on . Time spent in review: SECOND REVIEW/ UPDATE ❑ Approved ❑ Need more info. Reviewed by , on . Time spent in second review: THIRD REVIEW/UPDATE ❑ Approved ❑ Need more info. Reviewed by , on . Time spent in third review.- Disclaimer- Mason County does not certify the quality of the work done in this Geotechnical Report. Page 2 of 2 Form Effective June 2008 MASON COUNTY Submittal Checklist COMMUNITY SERVICES Geotechnical Report Building,Planning,Envir—ental Health,Community Health Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item is found not applicable, the report should explain the basis for the conclusion. Note:Unless specifically documented, this report does not provide compliance to the International Residential Code Sections R403.1.7 for foundations on or adjacent to slopes, Section R403.1.8 for expansive soils or section 1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes. Applicant/Owner 4/h/ (�✓re. rf, ,s/r,, 4., Parcel# l l,2 /7— 1�,)! fJ0c) Site Address i ! T J( i ti.� J` 'LA", (�x J! JC'�� I(r'��' \ C Nl ✓ �y� /�h/ (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) C/—/ % (b) A discussion of specific soil types, Located on page(s) /f' `/ Z_ (c) A discussion of ground water conditions, Located on page(s) / Zr (d) A discussion of the upslope geomorphology.. Located on page(s) / Z (e) A discussion of the location of upland waterbodies and wetlands, Located on page(s) / Z- (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) Z (2) A site plan which identifies the important development and geologic features. Located on Map(s) (3) Locations and logs of exploratory holes or probes. Located on Map(s) 1 Z (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) / (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) /3 (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) 13— / S— (7) (a) Appropriate restrictions on placement of drainage features. Rev. February 2018 Located on page(s (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) S (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 16, (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) i t✓ (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) 1 (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) /7 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) !1 7 (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) 7 (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) / 7 (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) 7 I, C u� l Oh hereby certify under penalty of perjury that i am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical Report, dated )I— 12 - 2c12/ , and entitled �P ok Washf� SOW C`✓.e Z— II�L^ meets all the requirements of the Mason County Resource Ordinance, ? 2-J21 Geologically Hazardous Areas Section, is complete and true, that the Engineering Geologist assessment demonstrates conclusively that the risks posed by the X landslide hazard can be mitigated through the included geotechnical ��Sed Ge design recommendations, and that all hazards are mitigated in such a Cyr is Lie ojC��5- {� manner as to prevent harm to property and public health and safety. Page 2 of 2 Disclaimer, Mason County does not certify the quality of the work done in this Geotechnical Report. INVOICE NW GREEN CONSTRUCTION INC. 261 HAMILTON ROAD N CHEHALIS,WASHINGTON 98532 RE: LOTS 1&2 TRI OF SW NE&SE NW Ex ST R/W ALLYN,WASHINGTON 47.399 -122.835(between lots 1 &2) PARCEL 12217-24-00010 NOVEMBER 12,2021 Dear NW Green: Please find below the charges for the geotechnical report for the above referenced property in Allyn, Washington. The total due is$2,900.00,made payable to All American Geotechnical,Inc.at the address below. All American Geotechnical 8947 Buttonwood Lane NE Olympia,WA 98516 Included are: Site visit and report $2,900.00 Total charge: S2,900.00 Thank you for letting us work with you on this project. Payment due on receipt. ALL AMERICAN GEOTECHNICAL Curtis D Cushman Senior Engineering Geologist Owner AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 1 Phone#:(360)491-5155 Cell#(360)481-6677 GEOTECHNICAL REPORT FOR LOGGING NW GREEN PROPERTY LOT 4 PART OF TR1 OF SW NE & SE NW Ex ST R/W ALLYN, WASHINGTON PREPARED FOR NW GREEN CONSTRUCTION INC. BY ALL AMERICAN GEOTECHNICAL OLYMPIA, WASHINGTON NOVEMBER 12, 2021 • ALL AMERICAN GEOTECHNICAL CONTACT INFORMATION PREPARER INFORMATION AAG PROJECT NUMBER: AAG21-146 CONTACT: CURTIS D.CUSHMAN ADDRESS: 8947 BUTTONWOOD LANE NE OLYMPIA,WASHINGTON 98516 TELEPHONE: (360)491-5155 CELL: (360)481-6677 EMAIL ADDRESS: CURTIS.CUSHMAN@COMCAST.NET CLIENT INFORMATION CLIENT: NW GREEN CONSTRUCTION TELEPHONE: (360)740-0345 BILLING ADDRESS: NW GREEN CONSTRUCTION 261 HAMILTON ROAD N CHEHALIS,WA 98532 SITE ADDRESS: STATE ROUTE 3 AT E HOMESTEAD DRIVE TR 1 OF SW NE&SE NW EX ST R/w ALLYN,WASHINGTON EMAIL CDHL@NWGREENHOMES.NET PARCEL NUMBER 12217-24-00010 GPS LOCATION: 47.399 -122.835 dd(between lots 1 &2) AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 2 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL ADDENDUM-2021 NW GREEN CONSTRUCTION INC. 261 HAMILTON ROAD N ALLYN,WASHINGTON 98532 RE: LOT 4 TR1 OF SW NE&SE NW Ex ST R/W ALLYN,WASHINGTON 47.399 -122.835(between lots 1 &2) PARCEL 12217-24-00010 NOVEMBER 12,2021 Dear NW Green: NW Green Construction Inc. (client)hired All American Geotechnical, Inc. (AAG) in August of 2021 to prepare a geotechnical report for the above-named property located off WA SR-3 at E Homestead Drive north of Allyn, Washington. The proposed development is to timber the lot and make it available for eventual development. The parcel noted above has been tentatively divided into 4 lots. This report deals with Lot 4 located on the southeast side of E Homestead Drive and extending to the southern property line and State Route 3. The timbering is required for eventual development but the type of development and any design elements for development are not addressed in this report. Because of steep slopes near the top of a natural drainage in the southeastern part of the lot and the steep slope leading down to SR-3 constitute Landslide Hazard Areas (LHA) a geotechnical report is required. This report will address this lot and will be submitted with the Mason County checklist. There will be no timbering of the Landslide Hazard Areas(LHA)described in this text and on Figure 2 in the appendix. The intent of this project is to harvest the timber and to provide room for future development. Harvesting will be done under the conditions and requirements of the logging permit. As per client request, we have conducted a soils exploration and slope stability analysis for the above- mentioned lots. The results of this investigation, together with our recommendations, are to be found in the following report. This report and the checklist will be sent by PDF to the client. Site geology was looked at in various locations. The lot has two geological deposits that will be detailed in the text. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 3 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL We appreciate this opportunity to be of service to you and we look forward to working with you in the future. If you have any questions concerning the above items,the procedures used,or if we can be of any further assistance,please call us at the phone number listed below. Respectfully Submitted, oI wash;. f ALL AMERICAN GEOTECHNICAL,INC. 0 eng 243 9�,�„i � Curtis D. Cushman,L.G.,L.E.G. Ge°� Senior Engineering Geologist Curtis Dean Cushman AAG21-144 8947 Buttonwood Lane NE,Olympia,WA 98516 4 Phone#: (360)491-5155 Cell#:(360)481-6677 ALL AMERICAN GEOTECHNICAL * TABLE OF CONTENTS CONTACT INFORMATION 2 INTRODUCTION 7 1) SITE CONDITIONS 8 SURFACE CONDITIONS 8 1)(A)SITE GEOLOGY 9 1)(B)SOIL TYPES 1 I 1)(C)GROUND WATER CONDITIONS 13 1)(D)UPSLOPE GEOMORPHOLOGY 13 1)(E)UPSLOPE WATERBODIES AND WETLANDS 13 1)(F) LANDSLIDE ACTIVITY 13 2) SITE PLAN 13 3) EXPLORATORY HOLES OR PROBES 14 4) PROPOSED DEVELOPMENT 14 5) CROSS SECTION 14 6) SLOPE STABILTY ANALYSIS 14 LIQUEFACTION AND SITE CLASS 15 GEOSEISMIC SETTING 15 LATERAL EARTH PRESSURES 16 7) RESTRICTIONS 16 A) PLACEMENT OF DRAINAGE FEATURES 16 B) PLACEMENT OF SEPTIC DRAIN FIELDS 16 C) PLACEMENT OF COMPACTED FILLS 16 D) BUFFERS 17 E) SETBACKS 17 8) CLEARING AND GRADING PLAN 17 9) EROSION CONTROL PLAN 18 10) ON AND OFFSITE IMPACTS 18 11) FINAL DEVELOPMENT CONDITIONS 18 12) STRUCTURAL MITIGATION 18 13) SITE PLAN 18 CONCLUSIONS AND RECOMMENDATIONS 19 PROVISIONS 19 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 19 READ THESE PROVISIONS CLOSELY 19 REFERENCES 21 AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 5 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmERICAN GEOTECHNICAL APPENDIX 23 2015 IBC DESIGN SPECIFICATIONS 24 SLOPE MODELS 26 STATIC MODEL A-A'LINE 26 DYNAMIC MODEL A-A'LINE 27 STATIC MODEL B-B'LINE 28 DYNAMIC MODEL B-B'LINE 29 FIGURES 30 FIGURE 1.VICIAIITY MAP 30 FIGURE 2.SITE PLAN 31 FIGURE 3. EROSION CONTROL NOTES 32 AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 6 Phone#: (360)491-5155 Cell#:(360)481-6677 ALL AmERICAN GEOTECHNICAL INTRODUCTION This report summarizes the results of our geotechnical consulting services for the timbering of Lot 4 on part of the parcel and is herein described. The lot is on the southeastern side of E Homestead Drive which comes off State Route 3 north of Allyn, Washington. The lot is approximately 19.3 direct air-miles northeast of downtown Shelton,Washington. The location of the site is shown relative to the surrounding area on the Vicinity Map,Figure 1. The lot is located on a larger parcel which,overall, is on a glacially-formed plateau cut be a large drainage that descends eastward to eventually arrive at North Bay, the deepest part of Case Inlet. The lot is south of this drainage but has a smaller one present near its southeastern corner. It is undeveloped with limited road access off E Homestead Drive. The geology is Vashon till and advanced outwash as described in "Geology,"below. Our understanding of the project is based on our discussions with the client and their agents. In general, there will be no grading and the only disturbance of the soil will be creating logging-quality access roads. The approximate layout of the site is shown on the Site Plan,Figure 2. The purpose of our services is to evaluate the surface and subsurface conditions at the site in order to satisfy the requirements of the Mason County Critical Areas Ordinance,and as a basis for providing geotechnical recommendations for the project. All American Geotechnical is therefore providing geologic and hydrogeologic services for the project. Specifically, our scope of services for this project includes the following: 1. A review of the available geologic,hydrogeological and geotechnical data for the site area. 2. A geologic reconnaissance of the site area and surrounding vicinity. 3. Investigation and identification of shallow subsurface conditions at the site by characterizing the exposed soil,reviewing published well logs, and sampling. 4. Comparison of site to published geologic maps,previous field investigations,and open file reports. Inspection of aerial photos is used to determine the geomorphology of the site. 5. Evaluation of the landslide, erosion, and seismic hazards at the site per the Mason County Critical Areas Ordinance regulations(as of 2019). 6. Dynamic and static slope stability modeling. 7. Geotechnical recommendations for fill placement, drainage, and typical erosion control measures (Figure 3). The most critical slopes are associated with the drainage and along the slope descending northeast toward SR-3. They exceed 40% and are greater in height than 10 feet. Therefore, Mason County requires that a geotechnical report be prepared in accordance with the Critical Areas Ordinance. As a general rule,the slope toward SR-3 would not be modeled for this report as an engineered roadway is commonly considered safe. However,to determine setbacks along such a steep feature, we are taking the liberty of including an analysis of this slope in this report. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 7 Phone#: (360)491-5155 Cell#:(360)481-6677 ALL AmERICAN GEOTECHNICAL 1) SITE CONDITIONS SURFACE CONDITIONS Lot 4 is an approximate triangle with sides corresponding to SR-3, E Homestead Drive, and the southern property line of the parcel. It has direct access from E Homestead Drive. Lot 4 was surveyed by Tumbow Land Surveying and has an area of 12.23 acres. The tops of the Landslide Hazard Areas (LHA) for the lot are well defined along SR-3 and also defined at the top of the drainage. These LHA breaks in slope will not be difficult to see when harvesting the timber. For obvious reasons,there are no 50-foot vegetation buffers drawn on Figure 2. The LHAs are marked on the map at the top of the slope and at the bottom. The lot is located at the entrance to the Lakeland Village development. Topographically, the lot extends from an elevation of 150 feet at its southeast corner to 250 feet in the center of the property where there is a broad plateau at that elevation. The lot has sufficient room for future development. There are only a few residences in the immediate area of the lot. The site exposure is to the east. The site was visited by Curtis D Cushman L.E.G. and Blaise Jelinek, E.I.T of All American Geotechnical on August 25,2021. The purpose of a site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. A site map was prepared identifying features of the property based on the Tumbow survey. Surficial exploration and sampling were performed. Sampling provides representative material for evaluation. Visual observations were documented. Site-specific features were mapped. Timbering is proposed for the lot in conformance with the applicable timbering permit. At the time of the site visit, active erosion was not observed on the parts of the lots that were accessible. No evidence of deep-seated slope instability was observed on site. Trees located on the property in general and in the immediate vicinity are seen to be predominately straight and vertical. There is no standing water of any orm and no springs. There was some evidence that ponding may occur in the rainy season. There are no streams but the drainage was carved by stream erosion, likely seasonal. There is no other evidence of surface water although there were some small natural drainages observed. The general topography of the site indicates that drainage flows overall to the east. &'L.V"A cti Cl/S/Z1 — Pyc'o 07t $pep fFw c4. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 8 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmEpicAN GEOTECHNICAL The LiDAR map to the `` i 0. right shows no _ F � landslides at the client property. To the north ! is a large mapped area that is apparently an .F y old landslide deposit. p A crescent scarp faces t to the northeast. With Highway 3 and Old :t Highway 3 crossing r A the debris below it. South of the roads the41 topography of the t' landslide debris is smooth,while north of the roads it appears fresher, with apparent - "hummocky terrain." This material is now cut by numerous branches of a small dendritic stream that flows to the east. This feature overall begins at least 300 feet from the northern corner of the lot and the failure appears stable at this time. 1)(A)SITE GEOLOGY The site is situated within the Puget Sound glacial province. The existing topography, as well as the surficial and shallow subsurface soils in the area, is the result of the most recent Vashon Stade (stage) of the Fraser glaciation that occurred between about 9,000 and 11,000 years ago,and weathering and erosion that has occurred since. A description of the surficial soils is included in the"Site Soils,"below. In general, the soil units are derived directly from the underlying Vashon till to be described,below. The Geologic Map of the Belfair 7.5-minute Quadrangle Mason, Kitsap, and Pierce Counties, Washington Open File Report 2009-7 by Polenz, M. and others through the Washington Division of Geology and Earth Resources is the primary source for the following, taken from The Mason County GIS: Qgt(Vashon till) Geologic Unit Symbol: Qgt Geologic Unit Age: Pleistocene Geologic Unit Name: Vashon Stade till Publication Source: WGS Publication Number: OFR 2009-7 Quadrangle Name: Belfair AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 9 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmERICAN GEOTECHNICAL Unit Description: Unsorted, unstratified(but locally banded) mix of clay, silt, sand, and gravel; typically supported by a sandy matrix; mostly gray but locally ranging to tan, light brown, or orange; typically unweathered; lodgment till compact, with well-developed facies resembling concrete, but near the surface commonly hackly and(or)looser and covered by 1 to 6 ft of loose ablation till; deposited directly by glacial ice and commonly includes clasts or clumps plucked from underlying units. Clasts are commonly striated and faceted, with angular or rounded edges... Age: Pleistocene Lithology: continental glacial till Age-Lithology: Pleistocene continental glacial till This will be the general geology as seen in the field and on the mapping. However,there also are also exposed sections of: Qga (Vashon Stade advance outwash) Geologic Unit Symbol: Qga Geologic Unit Age: Pleistocene Geologic Unit Name: Vashon Stade advance outwash Publication Source: WGS Publication Number: OFR 2009-7 Quadrangle Name: Belfair Unit Description:Pebble to cobble gravel, sand, and layers and lenses of silt and clay;gray to tan; typically stratified, well rounded, well sorted, and clean (<5 percent silt or clay in matrix), except in less- sorted and more angular ice proximal deposits.... Age: Pleistocene Lithology: continental glacial drift Age-Lithology: Pleistocene continental glacial drift This unit is seen here as dominantly sand,which,while compact where undisturbed, is easily loosened by cutting with a bulldozer blade. There is locally the mapping of Qgas— Vashon Stade advance outwash which is similar to the above described Qga but mapped as dominantly sand. The Lakeland Village water well is the only one that is reasonably located which is near the lots. It is a mixed column with gravels and sand and local clay. This is in keeping with the Qgt over Qga seen in the field. Water is unlikely to be encountered in timbering or developing these lots. The Qgt Vashon till is ubiquitous to the region and is suitable for support of heavy equipment. The material encountered was SP—Poorly graded sand and likely GP,Poorly graded sandy gravel (ASTM classification). This latter was seen in the access roads entering the property and corresponds to the Qgt. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 10 Phone M (360)491-5155 Cell M (360)481-6677 ALL AMERICAN GEOTECHNICAL 1)(B)SOIL TYPES The USDA Web Soil Survey has mapped the site soil entirely as Alderwood gravelly sandy loam with the Ac soil predominant over the parcel on its eastern side. This soil is described as follows: Ac—Alderwood gravelly sandy loam, 15 to 30 percent slopes Map Unit Setting • National map unit symbol: 2t627 • Elevation: 0 to 1,000 feet • Mean annual precipitation: 25 to 60 inches • Mean annual air temperature: 46 to 52 degrees F • Frost-free period: 160 to 240 days Map Unit Composition • Alderwood and similar soils: 85 percent • Minor components: 15 percent Description of Alderwood Setting • Landform: Hills, ridges • Landform position (two-dimensional): Backslope • Landform position (three-dimensional): Nose slope, side slope, talf • Down-slope shape: Convex, linear • Across-slope shape: Convex • Parent material: Glacial drift and/or glacial outwash over dense glaciomarine deposits Typical profile • A - 0 to 7 inches: gravelly sandy loam • Bwl - 7 to 21 inches: very gravelly sandy loam • Bw2 - 21 to 30 inches: very gravelly sandy loam • Bg - 30 to 35 inches: very gravelly sandy loam • 2Cdl - 35 to 43 inches: very gravelly sandy loam • 2Cd2 - 43 to 59 inches: very gravelly sandy loam Properties and qualities • Slope: 15 to 30 percent • Depth to restrictive feature: 20 to 39 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 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water supply, 0 to 60 inches: Very low (about 2.7 inches) The remained of the parcel is mapped as the Alderwood Ab which is on gentler slopes. Ab—Alderwood gravelly sandy loam, 8 to 15 percent slopes AAG21-146 8947 Buttonwood Lane NE, Olympia, WA 98516 1 1 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL Map Unit Setting • National map unit symbol: 2t626 • Elevation: 50 to 800 feet • Mean annual precipitation: 20 to 60 inches • Mean annual air temperature: 46 to 52 degrees F • Frost-free period: 160 to 240 days Map Unit Composition • Alderwood and similar soils: 85 percent • Minor components: 15 percent Description of Alderwood Setting • Landform: Hills, ridges • Landform position (two-dimensional): Shoulder • Landform position (three-dimensional): Nose slope, talf • Down-slope shape: Convex, linear • Across-slope shape: Convex • Parent material: Glacial drift and/or glacial outwash over dense glaciomarine deposits Typical profile • A - 0 to 7 inches: gravelly sandy loam • Bwl - 7 to 21 inches: very gravelly sandy loam • Bw2 - 21 to 30 inches: very gravelly sandy loam • Bg - 30 to 35 inches: very gravelly sandy loam • 2Cdl - 35 to 43 inches: very gravelly sandy loam • 2Cd2 - 43 to 59 inches: very gravelly sandy loam • Properties and qualities • Slope: 8 to 15 percent • Depth to restrictive feature: 20 to 39 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 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water supply, 0 to 60 inches: Very low (about 2.7 inches) This mapping is somewhat misleading, as the Alderwood Ac is mapped over an area that is clearly less than 15 degrees of slope. This is thus Ab. EROSION HAZARD CLASSIFICATION The purpose of the Erosion Hazard Section is to identify areas that present potential dangers to public health and safety, and to prevent the acceleration of natural geological hazards, and to neutralize the risk to the property owner from development activities. AAG21-146 8947 Buttonwood Lane NE, Olympia, WA 98516 12 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL Areas in Mason County underlain by soils, which are subject to severe erosion when disturbed. Such soils include,but are not limited to, those for which potential for erosion is identified in the Soil Survey of Mason County,USDA Soil Conservation Service, 1960, or any subsequent revisions or additions to this source. These soils include, but are not limited to, any occurrence of River Wash ("Ra') or Coastal Beaches ("Cg') and the following when they occur on slopes 15%or steeper: a. Alderwood gravelly sandy loam ("Ac"and "Ad') b. Cloquallum silt loam ("Cd') c. Harstine gravelly sandy loam ("Hb') d. Kitsap silt loam ("Kc') The Alderwood Ab(5 to 15%slope)is not mentioned in the Soil Survey as having severe erosion potential. The steeped Ac(15 to 30%)is mentioned as having erosion potential if not controlled. Logging operations rarely exceed denudation of 5%, and most of it shall be on the lesser slopes of the Alderwood Ab. Proper care should avoid erosion hazards. A silt fence may be reaniredin the southeastern part of the lot north of the larger drainage where there is a steepening slope both toward SR-3 and the drainage. However, this may be avoided if a no-cut setback is used above thisa hypothetical silt fence. 1)(C)GROUND WATER CONDITIONS G yU\A,� C�W v e,)a k ? She a dd�k u w1 No surface water flow was observed on site. There was no evidence of springs on the slopes. 1)(D)UPSLOPE GEOMORPHOLOGY Just to the west of the parcel, the topography apexes at the approximately 390 foot height. The steepest slope measured on the GIS leading up to these heights was in the area of 25%. This does not represent a problem for the timbering operations nor for future development. 1)(E)UPSLOPE WATERBODIES AND WETLANDS There are none. 1)(F) LANDSLIDE ACTIVITY The only landslide in the area is the large but apparently complete one beginning over 300 feet to the north. There are no other landslides mapped in the area and there are none evident on LiDAR. There is no evidence of landslide activity at the lot anecdotally, seen on site, or on LiDAR. 2) SITE PLAN The location of the lot and the topography is shown on Figure 2. The LHAs are shown along with the geology and soil types. There are no plans for development at this time,so there is no residential footprints, access roads, and no septic drainfields shown. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 13 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL 3) EXPLORATORY HOLES OR PROBES The geologic column is well exposed in exposures on-site and in recent road-huts. The soil tested on-site is firm and unyielding. 4) PROPOSED DEVELOPMENT Figure 2 shows the general lay-out. Setbacks for logging will be discussed below. 5) CROSS SECTION Four cross-sections along lines A—A ' and B—B " are in the Appendix. 6) SLOPE STABILTY ANALYSIS Factors of safety were determined using the Bishop (semi-circular) method. The site was modeled monolithically with information from the volcanic unit described in the literature and as seen on-site. The parameters used in this modeling were based on experience with the surroundings and the types of materials encountered on site. A continuous load of 2500-lb per foot was placed at or near the upper Landslide Hazard Area. No groundwater was included in the model,based upon neighboring well logs and the stream base. Slope stability was modeled using the GALENA 6.1 program in both static and dynamic conditions (ca= 0.15,per Mason County Code). "Static" condition refers to an "as is" state of a given slope. "Dynamic" puts seismic acceleration into the model for earthquake conditions. The factor for ground acceleration(ca) was determined from the Peak Ground Acceleration from the USGS Seismic Design Maps,included in the Appendix. There were no deposits on site. The model is used here to approximate massive basalt outcrop. The site was modeled with the Qgt overlying Qga modeling units. The unit was modeled using the following parameters presented in Table L Geologic Modeling Values. Table 1. Geologic Modeling Values Geologic Unit Unit Weight Cohesion Phi Angle Qgt-Vashon Stade till I-).� 400 40 Qga-Pre-Vashon Glacial Advance 115 100 36 Four analyses were calculated along the two cross-sections, itemized on Table 2. Modeling Parameters and Findings. The Analysis Number corresponds to the output presented on pages 26-29. The slopes were modeled based upon observations,field measurements,and available mapping. Initial positions were selected based upon the placement of the structure and the shape of the slopes. The initial points were AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 14 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AwRICAN GEOTECHNICAL varied over the analysis range indicated; with 50 different positions tested across these ranges. A total of 125,001 calculations were performed for Analysis 1 through 6. Calculated Factors of Safety are presented in Table 2. Table 2.Modeling Parameters and Findings Analysis Load across Analysis Earthquake Slope to I Initial Positions(Analysis Range) Configurations Factor of Number Building Envelope Type Force Load Lower 1•pper Radius Analyzed Safety Cross-Section A-A' .. ......................................................................._.__..._............._._..._.__.................._........................._..............._.................... ...................._ .... ..._..__............ Analysis l 2500#145-165'_ .Static_ 1 0.0_. Below 170_30_ 's 155(50 105(30) ! 125,001 1.56 Ama1)s!! 2 1 2500#145 165 Dynamic 0150 Below 70(30) _l155(50) 105(30) 125,001 1.19 Cross-Section B-B' ......_...... ........ .........._._._......_..._...__...._..____.._: .. (_..__._.: _...._._...__..._�.._.._...fir.._.._... .. ._. al is 3 2500#125-145'. Static_._.___...__0.0 .......... _ 45(40) 1125 .40)_T120(40) _m .125,001_....._.}....._._1.97 Analysis 4 2500#125-145' Dynamici 0.150 a ;Below i45(40) '•125(40) 1 120(40) 125,001 1.53 Under static conditions, the slopes generally did not show susceptibility to deep-seated failure that would cause harm to the proposed logging operations. Under dynamic loading (Ca=0.15), the computations demonstrated that the slopes are safe with respect to the modeled areas. These calculated Factors of Safety meet the requirements set forth by Mason County that is, 1.50 for static and 1.1 for dynamic loading scenarios. Based on our slope models representing critical slopes at the subject sites, it is apparent that the logging site is not susceptible to damage by deep-seated movements or instability. LIQUEFACTION AND SITE CLASS The Liquefaction Susceptibility Map of Mason County, Washington by Palmer, Magsino, Poelstra, Bilderback,Folger,and Niggemann(September 2004)maps the site area as having being Very Low. The Site Class Map of Mason County, Washington by Palmer,Magsino,Bilderback, Poelstra,Folger, and Niggemann(September 2004)maps the site area as site class C. Site class C is Very Dense Soil,Soft Rock. GEOSEISMIC SETTING According to the Seismic Zone Map of the United States (Figure 1613.3.1(1)) contained in the 2015 International Building Code (IBC), the project site is located where the maximum spectral response acceleration is 55 percent of gravity (g). Site-specific seismic parameters are presented on the "Seismic Design Summary"in the Appendix of this report. We recommend following seismic factors for design purposes. • Site Class: C(soft rock) AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 15 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL • Spectral response acceleration,short period(SMs): 1.422g(Fa= 1.0) • Spectral response acceleration, 1-second period(SMi): 0.741g(F,,= 1.3) • Peak Ground Acceleration(PGA) 0.589g LATERAL EARTH PRESSURES Lateral loads may be resisted by friction on the bases of footings and floor slabs and as passive pressure on the sides of footings. An allowable coefficient of friction of 0.40 may be used to calculate friction between the concrete and the underlying native soil. We recommend the following be used to determine the lateral earth pressures considering the onsite SP or GP • �(soil friction angle) 36 degrees • Ko(at rest earth pressure coefficient) 0.412 • Ka(active earth pressure coefficient) 0.259 • Kp (passive earth pressure coefficient) 3.85 • y(soil unit weight) 118 pcf 7) RESTRICTIONS A) PLACEMENT OF DRAINAGE FEATURES There are no drainage features as there are no developmental plans at this time. No surface water and no storm discharge of any sort should be directed toward the steep slopes. B) PLACEMENT OF SEPTIC DRAIN FIELDS There are no plans to develop and hence no septic plans. C) PLACEMENT OF COMPACTED FILLS RECOMMENDATIONS FOR SITE PREPARATION There are few limitations on timber development and these are commonly in the timbering permit. All roads should be placed so there is little chance of downslope erosion in keeping with general practices common in the industry. As there are no plans to cut on the LHA slopes, silt fences will not be needed if care is taken to keep storm water from attacking any areas of reduced ve etg ation or-denudation by the logging. A silt fence may be needed if cuttin_�is to descend to the area indicated by the fence,but with a large buffer of uncut trees, is may not be necessary. Material on site may be suitable for structural fill. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 16 Phone#: (360)491-5155 Cell#:(360)481-6677 ALL AMERICAN GEOTECHNICAL Where placement of fill material is required, the exposed subgrade areas should be compacted to a firm and unyielding surface prior to placement of any fill. Over-excavation in any building area should be backfilled with structural fill, compacted to the density requirements described in the "Structural Fill" section of this report. If structural fill is needed, we recommend that a member of our staff evaluate the exposed subgrade conditions RECOMMENDATIONS FOR STRUCTURAL FILL Fill for this site would be native or import. All fill material should be placed as structural fill. In general, the structural fill should be placed in horizontal lifts of 8 inches to allow adequate and uniform compaction of each lift. Fill should be compacted to at least 95 percent of MDD (maximum dry density as determined in accordance with ASTM D-1557)to grade. The final appropriate lift thickness will depend on the fill characteristics and compaction equipment used. We recommend that our field representative evaluate the appropriate lift thickness during construction. Material placed for structural fill should be free of debris,organic matter,trash, and cobbles greater than 6 inches in diameter. The moisture content of the fill material should be adjusted as necessary for proper compaction. RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL Onsite soils may be considered for use as structural fill only if industry standards are satisfied. Fill material requirements are found on page 9-26 to 9-30 of the WSDOT Standard Specifications 2010. In general, a native soil (sand, silt, and gravel) encountered on a site must have less than 10 percent fines (material passing the US No. 200 sieve)to be suitable for use as structural fill. D) BUFFERS There are no vegetation buffers mapped on Figure 2. The object of this report is to evaluate a timbering operation and not the vegetation buffers of a residential development. E) SETBACKS No geotechnical setback is required but heavy equipment should observe a setback of 10 feet from any LHA.. All other setbacks are to be observed. 8) CLEARING AND GRADING PLAN There will be clearing as this is a logging operation. There may be grading, but there will be no roads going over the LHA, so standard procedures for logging operations may be allowed for this site. "No Disturb"zones will not be required. There will be no removal of vegetation in the LHA. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 17 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL 9) EROSION CONTROL PLAN It is our opinion that the potential erosion hazard of the site is not a limiting factor for the proposed developments. Revegetation as needed should occur immediately following timbering. Temporary and permanent erosion control measures should be implemented and maintained during construction and/or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential receiving waters. Erosion control measures may include, but not be limited to, silt fences, berms, and swales with ground cover/protection in exposed areas. No re-contouring of the site will occur. We do not believe extensive erosion control will be needed as most of the timbering is on low slopes and potential water erosion may be readily managed. Areas that are fully denuded of vegetation will require covering and possibly reseeding if necessary to prevent erosion. Otherwise, the understory will quickly and readily re-establish itself in protecting the slopes. Straw, hay, or jute matting shall be used to cover exposed soils until permanent vegetation is established. A revegetation plan is not be required. Please see the erosion notes on Figure 3. This shows the recommended development of a silt fence (and also generic notes on drainage tightlines which are not applicable to this report). This is not recommended unless the work has denuded a slope. However, near the southeast corner above SR-3, a silt fence may be useful. 10) ON AND OFFSITE IMPACTS There should be no notable on- or offsite impacts if the project is completed according to the recommendations of this report and in accordance with all regulations and to the highest standards and practices of the logging firm. 11) FINAL DEVELOPMENT CONDITIONS The lots are not ready for final development. Following the timbering,the lots will be developed depending on the client's timetable. The site must be left in a state that will not create erosion conditions and/or excessively increase water flow. Eventually, the development will follow all guidelines and regulations and will be geotechnically reviewed prior to permitting for construction. 12) STRUCTURAL MITIGATION There is none. 13) SITE PLAN Please see Figure 2. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 18 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL CONCLUSIONS AND RECOMMENDATIONS Based on the results of our site investigation, subsurface observations, and our experience in the area, it is our opinion that the site is suitable for the proposed timbering project. If properly done to standard practices, the lots appear suitable for the work and the work will not create erosion hazards. Proper drainage control measures will reduce or eliminate the potential for erosion in this area. Revegetation should be done as per recommendations in the text, above. PROVISIONS We have prepared this report for the exclusive use of Northwest Green Construction, Inc. and their authorized agents for Lot 4 off E Homestead Drive in Mason County, Washington. Site inspections, research, and mapping have culminated in this report. This report is intended to meet the requirements of the Mason County Critical Areas Ordinance. This report does not specify setbacks for: line-of-sight setbacks, FWHCA setbacks, eagle tree setbacks, wetland setbacks, or property line setbacks. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, expressed or implied, should be understood. Clients and property owners must understand that,despite any calculated Factors of Safety,surficial failure and landslides can and do occur on steep slopes. The property owner should monitor the stability of the site following timbering. Moreover, acceptable Factors of Safety do not guarantee there cannot be failures. It is the responsibility of the property owner to understand that there are always risks in developing on or near steeply sloped areas. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to onsite personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals, and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments,claims and disputes.All American Geotechnical includes these explanatory"limitations" provisions in our reports to help reduce such risks. The equipment,techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, geotechnical AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 19 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL engineering or geologic reporting does not usually relate any environmental findings, conclusions or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 20 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL REFERENCES MAPS DeLorme 3-D TopoQuads(2002),Source Data USGS,Yarmouth,Maine. Dragovich,Logan,Walsh, and Schasse(2002), Geological Map of Washington—Northwest Quadrant(Geological Map GM- 50),published by Washington State Department of Natural Resources. Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann (September 2004), The Liquefaction Susceptibility Map of Mason County, Washington,published by Washington State Department of Natural Resources. Pahner, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004), The Site Class Map of Mason County, Washington,published by Washington State Department of Natural Resources. Rogers,A.M.,Walsh,T.J.,Kockelman,W.J.,and Priest,G.R.(1996),Map showing known or suspected faults with quaternary displacement in the Pacific Northwest,published by U.S.Geological Survey OFR 91-441-0,Plate 1,scale 1:2,000,000. Smith,Carson(1977),Relative Slope Stability of the Southern Hood Canal Area, Washington,prepared in cooperation with the Washington Department of Natural Resources Division of Geology and Earth Resources; and, Department of the Interior United States Geological Survey. PUBLICATIONS ASTM International(2005),Annual Book of Standards 2005, Section 4, Volume 4.08,published by ASTM International,West Conshohocken,Pennsylvania. International Code Council,Inc.(2006),2006 International Building Code,published by International Code Council,Inc. Kollmorgen Instruments Corporation(1994),Munsell Soil Color Charts(1994 Revised Edition),published by Macbeth Division of Kollmorgen Instruments Corporation,New Windsor,New York. Ness,Fowler,Parvin(1960),The Soil Survey of Mason County, Washington, USDA Soil Conservation Service,in cooperation with the United States Department of Agriculture,and Washington Agricultural Experimental Station,and the Soils Conservation Service. Parks, Neal, Koloski, Laprade, Molinari, Butler, and Lorentson (November 2006), Guidelines for Preparing Engineering Geology Reports in Washington,published by Washington State Geologist Licensing Board,Olympia,Washington. Sowers(1979),Introductory Soil Mechanics and Foundations:Geotechnical Engineering,Macmillan Publishing Co.,Inc. AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 21 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL WEBSITES(ALSO ON MASON COUNTY GIS,WASHINGTON GEOLOGIC INFORMATION PORTAL,AND USDA WEB SOIL SURVEY) Mason County Government Information Services (http://www.co.mason.wa.us) Mason County Codes,Ordinances,and Regulations (http://www.co.mason.wa.us/code) Vegetation Management Guide for Puget Sound Bluff Property Owners (http://www.ecy.wa.gov/biblio/933 I.html) United States Department of Agriculture Natural Resource Conservation Service (http://soildatamart.nres.usda.gov) Washington Administrative Code (http://apps.leg.wa.gov/wac/) Washington Department of Ecology (http://apps.ecy.wa.gov/welllog) (https:Hfortress.wa.gov/ecy/coastalatlas/viewer.htm) AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 22 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL APPENDIX USGS Seismic Design Specifications Slope Models Figure 1.Vicinity Map Figure 2. Site Plan Figure 3.Erosion Control Notes AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 23 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL 2015 IBC DESIGN SPECIFICATIONS CHazards by Location Search Information RC[lmorul Seattle Coordinates: 47.398,-122.835 309 ft Elevation: 309 k I Timestamp: 2021-11-10T18:55:04,939Z Hazard Type: Seismic TaCortta ..lip. 0 Reference IBC-2015 <_ Document: ' Google olvilf>Rrs Map data s2021 Google Risk Category: III Site Class: C MCER Horizontal Response Spectrum Design Horizontal Response Spectrum Sa(g) Sa(g) 1.40 1.20 0.80 1.00 0.60 0.80 0.60 0.40 0.40 0.20 0.20 0.00 0.00 0 5 10 15 Period(s) 0 5 10 15 Period(s) Basic Parameters Name Value Description SS 1.422 MCER ground motion(period=0.2s) S1 0.57 MCER ground motion(period=l.0s) Sn1s 1.422 Site-modified spectral acceleration value SM1 0.741 Site-modified spectral acceleration value SIDS 0.948 Numeric seismic design value at 0,2s SA SD1 0.494 Numeric seismic design value at 1,Os SA Additional Information Name Value Description SDC D Seismic design case:ory I a 1 Site amplification factor at 0.2s F 1.3 Site amplification factor at 1.Os CRS 0.961 Coefficient of risk(0.2s) AAG21-146 8947 Buttonwood Lane NE, Olympia, WA 98516 24 Phone#: (360) 491-5155 Cell#: (360) 481-6677 ALL AMERICAN GEOTECHNICAL 2015 IBC Design Specifications Continued CR1 0.939 Coefficient of risk(1.0s) PGA 0.589 MCEG peak ground acceleration FpGA 1 Site amplification factor at PGA PGA, 0.589 Site modified peak ground acceleration Tt 16 Long-period transition period(s) SsRT 1.422 Probabilistic risk-targeted ground motion(0.2s) SsUH 1.45 Factored uniform-hazard spectral acceleration(2%probability of exceedance in 50 years) SsD 2.027 Factored deterministic acceleration value(0,2s) S1RT 0.57 Probabilistic risk-targeted ground motion(1.0s) S1UH 0.608 Factored uniform-hazard spectral acceleration(2%probability of exceedance in 50 years) S1D 0.675 Factored deterministic acceleration value(1.0s) PGAd 0.726 Factored deterministic acceleration value(PGA) The results indicated here DO NOT reflect any state or local amendments to the values or any delineation lines made during the building code adoption process. Users should confirm any output obtained from this too/with the local Authority Having Jurisdiction before proceeding with design. Disclaimer Hazard loads are provided by the U,S.Geological Survey Seismic Design Web Services, While the information presented on this website is believed to be correct,ATC and its sponsors and contributors assume no responsibility or liability for its accuracy.The material presented in the report should not be used or relied upon for any specific application without competent examination and verification of its accuracy,suitability and applicability by engineers or other licensed professionals.ATC does not interd that the use of this information replace the sound Judgment of such competent professionals,having experience and knowledge in the field of practice,nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the report provided by this website. Users of the information from this website assume all liability arising from such use.Use of the output of this website does not imply approval by the governing building code bodies responsible for budding code approval and interpretation for the building site described by latitude!longitude location in the report. AAG21-146 8947 Buttonwood Lane NE,Olympia, WA 98516 25 Phone#: (360) 491-5155 Cell#: (360)481-6677 ALL AwRicAN GEOTECHNICAL SLOPE MODELS STATIC MODE A A LINE § \ k « 7 / ± $ { U cu « f f f0 ( \ _ � a = $ fCD $ 3 3 a, \ f !- J; � = la, \ ! S ® . k � ) : \ f ) 2 ( a } \ § § m � I a U0 / / y y ~ / ° $ 7 \ ~ \ } / AAG21-14 84 Buttonwood Lane NE,Olympia,WA9516 26 Phone* (6)4!3!S Ce!! % (6)4l-67 ALL AMERICAN GE O TE C HNI CAL DYNAMI MODE A A LINE co f ! k » 7 / - // { 2 ~ 7 � ] ) \ 5 q 7 _ ® \ a \ \ 5 � f ) \ k E 2 \ /I \ \� a / \ � \ \ � � � \ � \ 131 . � \ ƒ � & { : / $ \ . ) \ / 2 m $ k@ / / } / % q R ] 2 ± ± _ — f k ƒ \ / - AA02 yl4 8947 Buttonwood Lane NE Olympia,WA 98516 77 Phone% (6)4!3l55 Ce!! %(6)4l-67 ALL AmERicAN GEOTECHNICAL STATIC MODEL B-BI LINE z 0 2 \ \ � � \Wo 1-1 U7 -ze / � i � � o « S2 5 \ � ) tu 04 / � - «KG21 146 8947 Buttonwood Lane NE,Olympia,WA 98516 28 Phone#: (60)491-5155 Cell#:(60)481-6677 ALL AMERICAN GEOTECHNICAL DYNAMIC MODEL B-B'LINE R _ (cp H N C F 5 O S N zl a 0 N N Y 8 m Y of F Q r: J a aLU c m R $ C g R 8 8 g s AAG21-146 8947 Buttonwood Lane NE, Olympia,WA 98516 29 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL FIGURES FIGURE 1.VICINITY MAP 122°52'00'W 122'51'00"W 22"SO'il0'V) WGS84 122°49'OC"W 'a .3: I.. � ! �.• •/ iBM 12 .:r �` � •� 1 V AIM• \ � 9 't fk r u ,�.._..— q V vt 7 I ` z v �f ,y I v M1 w � 122°S2'00"W 122°51'00"W 122'50'00"W WGS84 122°49'0C"W Mtf 16c 000 fft1 0 rd0 lowtor1BS Mated f=TOPO!C'001\eti-1 Ge:—P -'-Id c¢s r:nstis,tepo.tom) AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 30 Phone#: (360)491-5155 Cell#:(360)481-6677 NOTES o of Wash; This is not a survey. This map is a presentation of information from county,state,and federal agencies,client provided information,and onsite observations;for discussion purposes of the report with which this map is Qgn included. .,�� C a � EnyreerNg neokpn 2439 •�9�' c ansed Geo�o Site son , rcurtis Dean Cushman Ab—Alderwood gravelly sand loam, 8 to 15 percent slope. Af � Ac—Alderwood gravelly sand loam, \ 15 to 30 percent slope. Qga Site Geology ti r'en• Qgt—Vashon Stade till 0` Qge—Vashon Stade advance outwash 4ae � Qgt Qgas--Vashon Stede advance outwash sand Af—ArtiScalFill ,aC64wCpOOO �\` Si ` as Needed J Qgas \ o TO • i• ` ! 274.4 \ AC 973.43' 264D 1 Inch=120 Feet � / Ab � r 0 60 120 240 1% s % � 11N Contour Interal=5 feet / All American Geotechnical,Inc. Project Drawn By: Site Plan Lot 4 8947 Buttonwood Lane NE Number: BWl Forest Practices Permit Number: Parcel Number: 12217 42-00010 Figure Olympia,Washington 98516 AAG21-146 11/12/2021 Allyn,WA Applicant NW Green Construction XXX-E Homestead Drivc 2 PP Site Address: FILTER FABRIC MATERIAL SO'WIDE ROLLS USE STAPLES OR WIRE RING TO ATTACH FABRN:TO WIRE 2'X2'X14 GAUGE WIRE FABRIC OR EQUIVALENT GENERAL EROSION CONTROL NOTES: 2' 1. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIORTOTHE BEGINNING OF CONSTRUCTION.THE PROJECT ENGINEER AND THE COUNTY S� \ GROUND SURFACE /,n\;; SHALL INSPECT AND APPROVE THE INSTULATION OF 1121NCH MINIMUM DIAMETER STEEL ROD EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUCTION. (STRAP)CLAMPED SECURELY TO PIPE 2.EROSION CONTROL MEASURES ARE NOT LIMITED TO THE ITEMS CORRUGATED TIGHTLINE4INCH •; $MAX ON THIS PLAN.THE CONTRACTOR IS RESPONSIBLE FOR THE INSTALLATION AND MAINTAINANCE OF ALL EROSION CONTROL MEASURES. MINIMUM,6 INCH SUGGESTED NO SILTATION OF EXISTING OR PROPOSED DRAINAGE FACILITIES SHALL BE ALLOWED.CARE SHALL BE TAKEN TO PREVENT MIGRATION MT,yJMO Z'XI'WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER OF SILTS TO OFF SITE PROPERTIES. r"'"-�' "a $p M10 F BETTER OR EQUALALTERNATE: MATERIAL IN B'%1TTRENCH :' STEEL FENCE POSTS 3.THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL EROSION 'yew!% ,Ii;V•�>y}ai:•. N CONTROL MEASURES AND MACE ANY NECESSARY REPAIRS OR ADDITIONS :' "`'t•'=h �.ye.: r.• TO THE EROSION CONTROL MEASURES.THE CONTRACTOR SHALL PROVIDE tit: •.,,`.��d.,.�:4._•w.�...�_ ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECESSARY � `'`�" " 'k• `! ..D;?.ate. . :!:•C�S.y:=�' BY THE COUNTY INSPECTOR AND/OR THE PROJECT ENGINEER.FAILURE ` 1Y1+'-�'t'`" w'r'-`•"?'�%>�' FILTER FABRIC 6' TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL '; "`"�•~•�'APT"•'�T'+;"\fir` REQUIREMEWITH Y RESULT IN CIVIL PENALTIES BEING LEVIED 2'X7XI4 GAUGE WIRE ,.- ••: .. AGAINST THE CONTRACTOR AND/OR PROJECT OWNER. '=A)+' i 1••T'CPy'�,':th>ti' FABRIC OR EQUIVALENT '5''S,)F'� T "� 'h�i�".•�tt" h w d.DURING THE WET SEASON NOVEMBER TO MARCH ALL DISTURBED SOILS GROUND SURFACE S'-O' ( ) s:... SHALL BE STABILIZED WITHIN IB HOURS AFTER STOP OF WORK.EROSION °+^^�S:'+'F•'�' i '.rtyr�!'.}tiiy�••AN'.�':`?p `YY. :Iw1r:�Vf.i�:• PROVIDE BN•-1 I2 WASHED CONTROL MEASURES SMALL INCLUDE,BUT NOT BE LWIRED TO, :A:ti•a,', y,•,.� COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WITH P �•=z�rT' '`y"`'•` GRAVEL SACKFILL IN TRENCH 12' PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH. '..�4.f4 r?:`'rr,,,••,•'• MOON BOTH SIDES OF FILTER FENCE FABRIC ON THE SURFACE g•MI OR WOOD CHIPS.SEEDING OF THE DISTURBED AREAS SHALL TAKE PLACE AS WEATHER PERMITS. TIGHTLINE ANCHORED WITH TWO, 2'Xd'WOOD POSTS S.ALL SEEDED OR SODDED AREAS SHALL BE CHECKED REGULARLY 3 FOOT REBAR LENGTHS OR BOLTS. ALT:STEEL FENCE POSTS TO MAKE SURE VEGETATIVE COVERAGE IS COMLETE.AREAS SHALL BE REPAIRED,RESEEDED.AND FERTILIZED AS REQUIRED. FILTER FABRIC FENCE NOTES: 1.FILTER FABRIC SHALL BE PURCHASED INA CONTWUOUS ROLL CITE TO 6.TRACKING OF SOIL OFFSITE WILL NOT BE ALLOWED.IF ANY SOIL IS TRACKED ONTO A COUNTY STREET,IT SHALL BE REMOVED BY THE END THE LENGTH OF THE MR0.IER TO AVOID USE OF JOINTS.WHEN JOINTS ARE NECESSARY,FILTER CLOTH SMALL BE SPLICED TOGETHER ONLY AT OF THAT WORKING DAY.ANY FURTHER TRACKING OF MUD WILL THEN A SUPPORT POST WITH A MINIMUM CINCH OVERLAP AND SECURELY BE PREVENTED BY SWEEPING OR WASHING OF THE VEHICLES TIRES FASTENED AT BOTH ENDS TO THE POST. BEFORE DRIVING ON A COUNTY STREET. 2.PCSTS SHALL BE SPACED A MAXIMUM OF B FEET APART AND DIOVEN T.NO MORE THAN 500 LF OF TRENCH ON A DOWNSLOPE OF MORE THAN 5 SECURELY INTO THE GROUND(MINIMUM OF W INCHES). PERCENT SHALL BE OPENED AT ONE TIME. T VANEDAPOSTSA AND BINCHESWIDEAND RI].A TRENCH SMALL BE EXCAVATED B.EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OF TRENCHES. CYF FLARE END SECTION INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER L 9.TRENCH DEWATERING DEVICES SHALL BE DISCHARGED IN A MANNER THAT WILL ( QUARRY SPALL _ pt�•.',.,,-. 4.WHEN STANDARD STRENGTH FILTER FABRIC IS USED.A WIRE MESH OR ENERGY • / SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE NOT OFFSITEPROPERTIES. AFFECT FLOWING STREAMS.DRAINAGE SYSTEMS OR "Y r�'�'J°.{.�'v Y ^•' ''y✓+=ywr 1�,- DISPERSION DEVICEK'�'T':'•'- *:''.% ;•OF LONG, TI WIRES R HOG HEAVY-DUTY THE ERESHALL. STAPLES AT XLEASTNDINTO CH ITE PROPERTIES. .:F\•�+,r�:yyL.fT�Y. 1_�•iyaR,?ti, LONG,TIE WIRES OR HOG RINGS.THE WIRE SHALL EXTEND INTO THETRENC INCHES ABOVE THE OF 4 INAL ESMGROUND SURFACE FJRENO MORE THAN% 10.ALL STORM ON SHALL BE RECEIPROTECTEDNG SO OFF THAT SEDIMENT-LADEN THE PROJECT DURING INCHES ABOVE THE ORIGINAL GROUND SURFACE. CONSTRUCTION SHALL BE PROTECTED SO THAT SEDIMENTIADEN WATER I 7 GRASS-LINED SHALE SHOULD BE A WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM. MINIMUM ONE FOOT WIDE AT THE 5.THE STANDARD STRENGTH FILTER FABRIC SHALL SE STAPLED OR WIRED TO THE FENCE AND M INCHES OF FABRIC SHALL BE EXTENDED 11.ALL OFFSITE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE BOTTOM AND ONE FOOT DEEP WITH INTO THE TRENCH.THE FABRIC SHALL NOT EXTEND MORE THAN 36 SHALL BE PROTECTED FROM SILTATION. A MAXIMUM SLOPE OF 5 PERCENT. INCHES ABOVE THE ORIGINAL GROUND SURFACE.FILTER FABRIC SHALL NOT BE STAPLED TO THE EXISTING TREES. MINIMUM 4 FEET 12.ALL DISTURBED AREAS SMALL BE SEEDED ORSODDED UPON COMPLETION LEVEL SECTION S.WHEN THE WRTRE MESH S FILTER FABRIC AND CLOSER POST ELIMINATED.IN SUC IS OF WORK THE CONTRACTOR$HALL BE RESPONSIBLE TO ENSURE THAT USED.THE WIRE MESH SUPPORT FENCE MAP I E DDIRE IN SUCH COMPLETE COVERAGE A THE DISTURBED AREAS IS PROVIDED 8 THAT A CASE,THE FILTER FABRIC IS STAPLED OR WINED DIRECTLY IN THE GROWTH OF THE VEGETATION IS ESTABLISHED. GEOTEXTILE FABRIC POSTS WITH ALL OTHER PROVISIONS OR ABOVE NOTES APPLYING. ].FILTER FABRIC FENCES SHALL NOT BE REMOVED BEFORE THE UPSLOPE 13.CATCH BASINS SHALL TRAP SEDIMENT OR FILTER FABRIC MUST BE AREA HAS BEEN PERMANENTLY STABILIZED. PLACED UNDER GRATE UNTIL VEGETATION IS ESTABLISHED. S.FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH RAINFALL AND AT LEAST DAILY DURING PROLONGED RAINFALL ANY REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY. All American Geotechnical,Inc. Drawn By: BW J Erosion Control Notes Permit Number: Parcel Number: 12217-42-00010 Figure 8947 Buttonwood Lane NE 11/12/21 Forest Practices XXX-E Homestead Drive Olympia,Washington 98516 Revisions: Allyn,Washington Applicant Name: NW Green Construction Site Address: 3 12/9/21, 11:46 AM Re:Geo-Report for NW Green Const Lots 1 &2 "') Reply ® Delete Junk I V ••• X Re: Geo-Report for NW Green Const Lots 1 & 2 ��56 ° 4 CURTIS CUSHMAN <curtis.cushman@comcast.net> iJ Ej Reply Yesterday, 6:02 PM Michael MacSems Inbox Flag for follow up.Start by Thursday, December 09, 2021. Due by Thursday, December 09,2021. You replied on 12/9/2021 8:39 AM. Label: MasonCounty(3 months) Expires:3/8/2022 6:02 PM .'� Action Items Hello to you, Michael. I should have noted on all the reports (Lots 1 &2, 3, and 4), there were no close wells. The Village well, topographically lower or on the same elevation, hit water at -60 feet and that is its static level. I'm not sure of its location, either; the log has a P.O. Box on it. (Note that one log nearby has a well address in Gig Harbor.) I don't really like to use them unless they are solidly located. I think there will be no water encountered and I think the modeling is reasonable. The developers are aware that they'll need reports; I wrote all the reports only for the logging. I didn't see the clearing, but I don't get around too well, so I'll ask Blaise. Again, we did the survey for logging. If we're asked to do the development reports, we will do the geo in the light of where they wish to build. If it's too close to an LHA, we'll model it to get the setback. You may know from my previous reports that I am uneasy in crowding LHA slopes even with Factors of Safety that indicate they can be closer. Same here. As for the wells, how do you want me to write the above information? Yours truly, Curtis D Cushman --------------------------- Olympia, Washington On 12/08/2021 3:33 PM Michael MacSems <mms@masoncountywa.gov> wrote: https://owa.co.mason.wa.us/owa/projection.aspx 1/2 12/9/21, 11:46 AM Re:Geo-Report for NW Green Const Lots 1 &2 Reply ® Delete Junk I v ••• X I just read through your geo-report for Lot 1 and 2 for NW Green Construction (GEO 21-87-A). On checklist question 1.c, Ground Water conditions. Typically, this question is answered by estimating depth to ground water, usually by citing nearby well logs. Your answer talks about a lack of springs and seeps, which I think is an answer to a different question. Please go more in- depth (no pun intended) on the answer to this question. Other than that, the checklist looks okay. I do note that your geo-report is very clear that it only addresses logging and not eventual site development. As it happens, NW Green Construction has two permit applications in front of me, one for logging and the other for a large lot subdivision. The way Lot 1 is designed, there is no place on that proposed lot greater than 300' from the LHA, so that LLS application cannot be approved until a geo for site development has been prepared and approved. I will let the applicant know that. BTW, when you were on site did you notice that a building site had been cleared immediately next to the LHA on Lot 2? Thank you, Michael MacSems Subdivision, Forest Practices, Historic Preservation https://owa.co.mason.wa.us/owa/projection.aspx 2/2 Ge: (D i - ,r - cs j- MASON COUNTY J COMMUNITY SERVICES Geotechnical Report jBuilding,Planning,Environmental Health,Community Health Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed,and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item is found not applicable, the report should explain the basis for the conclusion. Note:Unless specifically documented, this report does not provide compliance to the International Residential Code Sections R403.1.7 for foundations on or adjacent to slopes, Section R403.1.8 for expansive soils or section 1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes. ApplicanUOwner 'Crrrc .) 7 1-f 0 y,-74 yc o Parcel# I2.2 I Z— 2 q e c ct o Site Address Tit r1L S'i rbt. C' i t.�yj✓ �12 � 3 I- 6-16-m4wS: T— (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) `I'—/6' (b) A discussion of specific soil types, Located on page(s) �i 3 (c) A discussion of ground water conditions, Located on page(s) 13 (d) A discussion of the upslope geomorphology, Located on page(s) I (e) A discussion of the location of upland waterbodies and wetlands, Located on page(s) (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) 1-' (2) A site plan which identifies the important development and geologic features. Located on Map(s) (3) Locations and logs of exploratory holes or probes. Located on Map(s) ' f (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) ";' (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) `1 (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) (7) (a) Appropriate restrictions on placement of drainage features; Rev. February 2018 Located on page(s ' (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) /61 (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) /(� -1 7 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 1 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 17 (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. Located on page(s) 1-7 (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) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) /E (11) 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 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) I, r7i r D C�5 th,? 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 Geotechniical Report, dated /// —7f01 and entitled meets all the requirements of the Mason County Resource Ordin ce, Geologically Hazardous Areas Section, is complete and true, that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geotechnical design recommendations, and that all hazards are mitigated in such a (Signature and Stamp) manner as to prevent harm to property and public health and safety. Page 2 of 2 Disclaimer. Mason County does not certify the quality of the work done in this Geotechnical Report. GEO2 � _ $1 fS 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: Al(A) C6\A,5�YLtC�1'0\4 Permit#: F FA Z 1 - 14 Parcel#: 1 72 1 ) z 9 - 0 G 0 1 C) Date(s) of the Document(s) reviewed: 12� � / Z t 1. (a) A discussion of general geologic conditions in the vicinity of the proposed development, OK? V Comment: e 1 (b) A discussion of specific soil types OK?_l Comment: i (c) A discussion of ground water conditions I OK? V Comment: j! I S $ �1IO(XVk01 uttn„ � � bti1Gr 1 (d) A discussion of the upslope geomorphoI y OK? 1, Comment: l 3 (e) A discussion of the location of upland waterbodies and wetlands OK? ✓ Comment: )'V 0`W F__ (11 )3 (f) A discussion of history of landslide sa t ��jjct itty in the vicinity, as available in the referenced maps and records OK? U Comment: 2. A site plan that identifies the important development and and geologic features. OK? ✓ Comment: f 13 4 J Z 3. Locations and logs of exploratory holes or probes. / l OK? Comment: (Y ) 4 — Ckl c11 CAI T3 4. The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides, and toe)on a geologic map of the site. OK? ✓ Comment: �- 2- 5. A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details of proposed grade changes. OK? �� Comment: - �( % h y1a 1X,IX,s I Lt 6. A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic safety factor is 1.1 and the quasi-static analysis coeffients should be a value of 0.15. OK? ✓ Comment: �' I H - / 6 7. (a) Appropriate restrictions on placement of d ainage f atures OK? V Comment: Q 19 _ (b) AppropriatVestrictions on placement fsept' drain fi ds OK? Comment: 0 it "` IVOY D- (c) Appropriate restrictions on placement of compacted fills and footings. OK? ✓ Comment: n} U Page 1 of 2 Form Effective June 2008 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. OK? V Comment: f I:) (e) Recommended setbacks from the landslid- hazard areas shoreline bluffs and the tops of other slopes. l/OK? - Comment: o 8. Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. OK? y"_Comment: 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. OK?_ -Comment: 10. An analysis of both on-site and off-site impacts of the proposed development. OK? ✓ Comment: J 11. Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. / OK? L Comment: 12. Recommendations for the preparation of structural mitigation or details of other proposed mitigation. OK? V" Comment: '1 ) S — G yy 13. A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of existing and proposed development on the site. OK? Comment: '1_ 2- Are the Documents signed and stamped?_Y By whom? CCA V } + S Cca S kwc License#: ��( `7 License type: L lcyyicecA 6ec,1 caq +g4 FIRST REVIEW Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by f0m)-, on I Z/ $ / Z I .Time spent in review: SECOND REVIEW/ UPDATE ❑ Approved ❑ Need more info. Reviewed by , on .Time spent in second review: THIRD REVIEW/UPDATE ❑ Approved ❑ Need more info. Reviewed by , on .Time spent in third review: Disclaimer. Mason County does not certify the quality of the work done in this Geotechnical Report. Page 2 of 2 Form Effective June 2008 NW GREEN CONSTRUCTION INC. INVOICE 261 HAMILTON ROAD N CHEHALIS,WASHINGTON 98532 RE: LOT 4 TRI OF SW NE&SE NW Ex ST R/W ALLYN,WASHINGTON 47.399 -122.835(behveen lots 1 &2) PARCEL 12217-24-00010 NOVEMBER 12,2021 Dear NW Green: Please find below the charges for the geotechnical report for the above referenced property in Allyn, Washington. The total due is $2,900.00,made payable to All American Geotechnical, Inc. at the address below. All American Geotechnical 8947 Buttonwood Lane NE Olympia, WA 98516 Included are: Site visit and report $2,900.00 Total charge: $2,900.00 Thank you for letting us work with you on this project. Payment due on receipt. ALL AMERICAN GEOTECHNICAL Curtis D Cushman Senior Engineering Geologist Owner AAG21-146 8947 Buttonwood Lane NE,Olympia,WA 98516 1 Phone#:(360)491-5155 Cell#(360)481-6677