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Home My WebLink AboutGEO2018-00068 for BLD2018-01029 - GEO Geological Review - 11/29/2018 �1��i801ONRECEIVED MASON COUNTY DEC 0 3 2018 Submittal Checklist • l COMMUNITY SERVICES Building,Planning,Environmental Health,Community Healt 1 J ,• /'Uder StreQeotechnical Report Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item 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. n p Applicant/Owner VL/%YP Parcel# Site Address e% c; (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) (b) A discussion of specific soil types, Located on page(s) & - C7 (c) A discussion of ground water conditions, Located on page(s) (d) A discussion of the upslope geomorphology, Located on page(s) / 0 (e) A discussion of the location of upland waterbodies and wetlands, Located on page(s) / 0 (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) /0 (2) A site plan which identifies the important development and geologic features. Located on Map(s) /D F/4 01r Z (3) Locations and logs of exploratory holes or probes. Located on Map(s) I /�—/G Wr 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) I 0 (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) 20 2 3 -2 L/ 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) /() - i Z (7) (a) Appropriate restrictions on placement of drainage features, Rev. February 2018 K Located on page(s 13 (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) 13 2- (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) (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) 14/ (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) l (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) / S (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) 115- (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) l (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) / 6- I, C v2nS 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 of W Geotechnical Report, dated and entitled meets all the requirements of the Mason County Resource Ordinance, Geologically Hazardous Areas Section, is complete and true, that the 2439 G g� assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geotechnical �Sed 0 design recommendations, and that all hazards are mitigated in such a Curtis Dean Cushman 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. i GEOTECHNICAL REPORT GAGE RESIDENTIAL SITE 419 NE BEARCREEK-DEWATTO ROAD BELFAIR, WASHINGTON PREPARED FOR VALERIA GAGE BY ALL AMERICAN GEOTECHNICAL OLYMPIA, WASHINGTON NOVEMBER 29, 2018 ALL AmEmcm GEoTEcnNtcAL CONTACT INFORMATION PREPARER INFORMATION AAG PROJECT NUMBER: AAG18-082 CONTACT: CURTIS D.CUSHMAN ADDRESS: 8947 BUTTONWOOD LANE NE OLYMPIA,WASHINGTON 98516 TELEPHONE: (360)491-5155 CELL/TEXT: (360)481-6677 EMAIL ADDRESS: CURTIS.CUSHMAN@COMCAST.NET CLIENT INFORMATION CLIENT: VALERIE GAGE ADDRESS: VALERIE GAGE 4739 BLACKBERRY HILL LN PORT ORCHARD,WASHINGTON 98366 SITE ADDRESS: 419 BEARCREEK-DEWATTO ROAD BELFAIR,WASHINGTON TELEPHONE: (360)769-2429—LAND (360)565-9317-CELL CLIENT CONTACT: TOM FULKERSON TELEPHONE: (253)230-6268 EMAIL ADDRESS: TFULKERSON@MSN.COM PARCEL: 12309-31-90074 GPS LOCATION: N470 29'37.81" W1220 48' 57.84" (at residential site) AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 2 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL Am N G T aNicAL SCOPE OF UNDERSTANDING VALERIE GAGE 4739 BLACKBERRY HILL LN PORT ORCHARD,WASHINGTON 98366 RE: GEOTECHNICAL REPORT 419 BEARCREEK—DEWATTO ROAD BELFAIR,WASHINGTON N470 29'37.81" W 122°48'57.84" PARCEL 12309-31-90074 NOVEMBER 29,2018 Dear Valeria Gage: Valeria Gage (client) hired All American Geotechnical, Inc. (AAG) in October 2018 to prepare a geotechnical report for a proposed single-family residence off Bearcreek-Dewatto Road north of Belfair, Washington. This is in keeping with a requirement of Mason County in the Critical Areas Ordinance in accordance with the Submittal Checklist For a Geotechnical Report. The site had but a few trees on the edges of the area to be developed. Proposed improvements include the replacement manufactured home and extending the parking area to accommodate a larger recreational vehicle. As per client request, we have conducted a soils exploration, foundation evaluation, and slope stability analysis for the above-mentioned parcel. The results of this investigation, together with our recommendations, are to be found in the following report. We have provided two copies for client review and distribution. 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, °t ash; ALL AMERICAN GEOTECHNICAL,INC. ��a r s/ Engin"nn9 G�ologyt t �.0 2439 �5 Curtis D. Cushman, L.G., L.E.G. sod Geoff° Senior Engineering Geologist Curtis Dean Cushman AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 3 Phone#: (360)491-5155 Cell#: (360)481-6677 . ALL AmimtcAN GRoTEcHNICAL TABLE OF CONTENTS ' SCOPE OF UNDERSTANDING 3 INTRODUCTION 6 1) SITE CONDITIONS 7 ' SURFACE CONDITIONS 7 ' A) SITE GEOLOGY 8 B) SOIL TYPES 8 C) GROUND WATER CONDITIONS 9 ' D) UPSLOPE GEOMORPHOLOGY 10 E) UPSLOPE WATERBODIES AND WETLANDS 10 F) LANDSLIDE ACTIVITY 10 2) SITE PLAN 10 3) EXPLORATORY HOLES OR PROBES 10 4) PROPOSED DEVELOPMENT 10 5) CROSS SECTION 10 6) SLOPE STABILTY ANALYSIS 10 ' GEOSEISMIC SETTING 12 LATERAL EARTH PRESSURES 13 7) RESTRICTIONS 13 A) PLACEMENT OF DRAINAGE FEATURES 13 B) PLACEMENT OF SEPTIC DRAIN FIELDS 13 1 C) PLACEMENT OF COMPACTED FILLS AND FOOTINGS 13 RECOMMENDATIONS FOR SITE PREPARATION 13 RECOMMENDATIONS FOR STRUCTURAL FILL 14 I RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL 14 D) BUFFERS 14 E) SETBACKS 14 8) CLEARING AND GRADING PLAN 14 9) EROSION CONTROL PLAN 15 10) ON AND OFFSITE IMPACTS 15 11) FINAL DEVELOPMENT CONDITIONS 15 12) STRUCTURAL MITIGATION 15 13) SITE PLAN 15 CONCLUSIONS AND RECOMMENDATIONS 16 PROVISIONS 16 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 16 READ THESE PROVISIONS CLOSELY 16 REFERENCES 18 AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 4 Phone#: (360)491-5155 Cell#: (360)481-6677 I ALLAMMCANGNOT&CMICAL I I APPENDIX 20 ' 2009 AASHTO DESIGN SPECIFICATIONS 21 2015 IBC DESIGN SPECIFICATIONS 22 I SLOPE MODELS 23 I STATIC MODEL A-A'LINE 23 DYNAMIC MODEL A-A'LINE 24 FIGURES 25 FIGURE 1.VICINITY MAP 25 I FIGURE 2.SITE PLAN 26 FIGURE 3. EROSION CONTROL NOTES 27 I I I I 1 I I I I I 1 I I I I 1 I AAG18-082 8947 Buttonwood Lane NE,Olympia,WA 98516 5 Phone#: (360)491-5155 Cell#: (360)481-6677 I I i ALL AmmcAN Gr&oTiErnrn iL i i INTRODUCTION This report summarizes the results of our geotechnical consulting services for the residential site herein described. The proposed residence is located north of Belfair, Washington. The site is accessed from i State Highway 3 via NE Old Belfair Highway which connects to the Bearcreek-Dewatto Road. The residential site is located on a shared private road south of the Bearcreek-Dewatto Road. The site is approximately 4 direct miles north of downtown Belfair. The location of the site is shown relative to the surrounding area on the Vicinity Map, Figure 1. I The parcel is a 1.2 acre irregular triangle, long to the north-south. The residential building site will be on a relatively flat area near the north end of the lot where there was a mobile home to be replaced by a new manufactured home. I Our understanding of the project is based on our discussions with the client's brother and information sent to us from AHC Homes. In general, this will be a project involving replacing one manufactures I residence with another. An area for RV parking is also proposed. The approximate layout of the site is I shown on the Site Plan, Figure 2. I I Figure 2 shows the footprint of the proposed manufactured home and the RV parking site. Figure 2 also shows the presence of a retaining wall proposed for the RV site as well as the steeper terrain to the I southeast of the site. I I 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 I geotechnical recommendations and design criteria for the project. All American Geotechnical is I therefore providing geotechnical services for the project. Specifically, our scope of services for this I project includes the following as needed: I 1. A review of the available geologic, hydrogeological and geotechnical data for the site I area. 2. A geologic reconnaissance of the site area and surrounding vicinity. I 3. Investigation and identification of 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 I file reports. Inspection of aerial photography is to determine the geomorphology of the I site. 5. Evaluation of the landslide, erosion, and seismic hazards at the site per the Mason County Critical Areas Ordinance regulations(as of January 1, 2007). 6. Building setbacks determined from static and dynamic slope stability modeling. 7. Geotechnical recommendations for site grading including site preparation, subgrade preparation, fill placement criteria (including hillside grading), temporary and permanent cut and fill slopes, drainage, and typical erosion control measures. The most critical slope is on the east side of the proposed building site. This is a slope that is greater than 40%with a height over 10 feet. Therefore, Mason County requires that a geotechnical report be prepared in accordance with the Critical Areas Ordinance. AAG 18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 6 Phone#: (360)491-5155 Cell#: (360)481-6677 I 1) SITE CONDITIONS SURFACE CONDITIONS The proposed building site is on a natural flat on a continuous slope descending from the northwest to the southeast. This natural platform is suitable for a single-family dwelling. Much of the area has been cleared, notably the pre-existing site for the residence. Blaise Jelinek E.I.T. of AAG visited the site for this project on November 5, 2018; at which time, Mark Gage, the brother of the client; was on site and explained the proposed improvements. The purpose of any site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. A site map is prepared identifying features of the property. Surficial exploration and inspection of subsurface samples were done. Visual observations were documented and site-specific features were mapped. The proposed development is on a platform underlain by glacial deposits. There is no extreme topography above the project site as it rises toward a north-south drumlin-like glacial ridge 1200 feet or more to the northwest part of which is an active aggregate operation. No surficial water is present. No active erosion was seen. { The LiDAR map to the right FIN. (from the Washington Interactive Geologic Map portal) is a bare earth depiction of the property. The " blocky terrain is depositional/erosional in nature and shows no active landsliding. The original mobile home has f j been removed from the site. X . The upper area of the site that - will be developed has but a few trees on the edges of the graded area to the south and west. The surface of the graded area is mostly gravel with sparse grass. The slope to the west has low growth plants and volunteers. The lower portion of the parcel to the west is forest. The site is too far inland to be mapped on the DOE Coastal Zone Atlas map. The LHA on the slope above the site of the proposed replacement mobile home is limited in height. The proposed site is located within the lower 50 foot vegetation buffer as seen on Figure 2, but as this is AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 7 Phone#: (360)491-5155 Cell#: (360)481-6677 1 ALL Ammcm GrmucaNICAL entirely cleared of old-growth and is currently vegetated with domestic plants and juvenile trees, development of the manufactured home inside tis buffer is acceptable. The slope below the site is defined as a landslide hazard area(LHA). The 50' vegetation buffer from this LHA will not impinge upon the development of the new manufactured home. A) SITE GEOLOGY The site is situated within the Puget Sound glacial province. The existing topography, as well as much of the sedimentary deposits and surficial 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" section of this report, below. In general, the deposits are composed of glacial material with the soils directly derived from this material. The Geologic Map of the Belfair 7-5-minute Quadrangle, Mason, Kitsap, and Pierce Counties, Washington Open File 2009-07 by Polenz, Michael, and others (2009), published by the Washington Division of Geology and Earth Resources, maps the site as follows. The description below is ordered with the younger deposits above the older. Qgic Vashon glacial ice-contact deposits—Sand, gravel, lodgment till, and flow till; minor silt and clay beds; tan to gray; variably sorted; loose to compact; massive to well stratified; locally includes over-steepened beds that typically reflect sub-ice flow, but their dip may, along with small-scale shears, also have developed as collapse features or due to glaciotectonic and tectonic deformation;formed in the presence of meltwater alongside ice, generally toward the end of the glaciation, and is thus commonly accompanied by stagnant-ice features, such as kettles and less- orderly hummocky topography, eskers (also separately mapped as subunit Qge), and subglacial or subaerial outwash channels. This description is characteristic of the site and the overall depositional area. Samples taken indicated the soil to be very gravelly sands and very gravelly loamy sands. . B) SOIL TYPES The soil (from the USDA WSS) at the site is: Ek—Everett very gravelly sandy loam, 15 to 30 percent slopes Map Unit Setting • National map unit symbol: 2t62c • Elevation: 30 to 900 feet • Mean annual precipitation: 35 to 91 inches • Mean annual air temperature: 48 to 52 degrees F • Frost free period: 180 to 240 days AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 8 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GrwncHNICAL Map Unit Composition • Everett and similar soils: 80 percent • Minor components: 20 percent • Estimates are based on observations, descriptions, and transects of the mapunit. Description of Everett Setting • Landform: Karnes, eskers, moraines • Landform position (two-dimensional): Backslope • Landform position (three-dimensional): Side slope • Down-slope shape: Convex • Across-slope shape: Convex • Parent material: Sandy and gravelly glacial outwash Typical profile • Oi - 0 to I inches: slightly decomposed plant material • A - I to 3 inches: very gravelly sandy loam • Bw-3 to 24 inches: very gravelly sandy loam • CI -24 to 35 inches: very gravelly loamy sand • C2- 35 to 60 inches: extremely cobbly coarse sand Properties and qualities • Slope: 15 to 30 percent • Depth to restrictive feature: More than 80 inches • Natural drainage class: Somewhat excessively drained • Capacity of the most limiting layer to transmit water (Ksat): High(1.98 to 5.95 in/hr) • Depth to water table: More than 80 inches • Frequency offlooding: None • Frequency of ponding: None • Available water storage in profile: Low(about 3.2 inches) This description well describes the soils seen on site. The surficial soil at the residential site were likely fully removed when the original mobile home was installed. Any further work will be in deeper soil, which is the same as the glacial deposit. C) GROUND WATER CONDITIONS No surface water flow was observed on site. There was no evidence of springs on the slope. AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 9 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AminuN GEOTECHNiCAL D) UPSLOPE GEOMORPHOLOGY The slope rises in an irregular fashion to the aggregate quarry on the crest of a drumlin over 1200 feet to the northwest. This area, under active exploitation, in on the other side of the Bearcreek-Dewatto Road from the client property and poses no hazard to the site. E) UPSLOPE WATERBODIES AND WETLANDS There are none. F) LANDSLIDE ACTIVITY The only landslides on the quadrangle are a few minor ones mapped as Qls in Courtney Creek over a half-mile to the southwest. Landslides of a minor size are also mapped in the headwaters of Hazel Creek to the north, again well away from the client property. 2) SITE PLAN The proposed location of the residential site is shown on Figure 2. The building envelope where this construction is acceptable from a geotechnical sense is marked. . 3) EXPLORATORY HOLES OR PROBES There were two soil excavations completed on the property. The soils encountered were very gravelly sands and loamy sands. 4) PROPOSED DEVELOPMENT Figure 2 shows the required features of. proposed construction, the boundaries of the hazard (LHA), and associated buffers and setbacks. 5) CROSS SECTION A cross-section along line A—A' is in the Appendix. 6) SLOPE STABILTY ANALYSIS As noted above, there are no mapped landslides in the area. LiDAR shows no landslides in the area of the proposed residence. There was no evidence of significant recent erosion observed onsite at the time of our investigations. In general, the undisturbed native soils of the site consist of a mixture of variable amounts of sand, silt, and gravel. These soil materials are in a dense condition except where they have been disturbed by AAG 18-082 8947 Buttonwood Lane NE,Olympia,WA 98516 10 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL A r,&RI N GEoTEc'HNICAL weathering activity and where they have been loosened by failure. Weathering, erosion, and the resultant sloughing and shallow landsliding are natural processes that can affect steep slope areas. Instability of this nature is typically confined to the upper weathered or disturbed zone, which has been disturbed and has a lower strength; however, the planned setback should prevent harm to the residence caused by major or minor slippages. Following construction, encouraging vegetation and discouraging runoff from the steep slopes can reduce erosion in steep slope areas such as this. Erosion control recommendations for the sloping areas are provided in the"Erosion Control" section of this report. 17.01.100E5 (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. Factors of safety were determined using the Bishop (semi-circular) method. The site was modeled monolithically with information from the glacial 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 1200-lb per foot was placed across the intercept of the proposed building envelope and the cross-sections. Slope stability was modeled using the GALENA 6.1 program in both static and dynamic conditions (ca= 0.224). "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. The soil was field identified as SP-SM Silty sand with gravel. These contain varying amounts of gravel and larger clasts but overall the deposits are matrix-supported. This classification requires selecting conservative values in the interests of safety. The site was modeled as a monolithic unit, based upon available mapping The units were modeled using the following soil parameters presented in Table 1. Geologic Modeling Values. Table 1. Geologic Modeling Values Geologic Unit Unit Weight Cohesion Phi Angle Qgic-- Vashon Ice Contact Deposits 118 250 ;7 Two analysis were calculated along the one cross-section, itemized on Table 2. Modeling Parameters and Findings. The Analysis Number corresponds to the output presented on pages 23-24. The slope was modeled based upon observations, field measurements, and available mapping. Initial positions AAG 18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 11 Phone#: (360)491-5155 Cell#: (360)481-6677 i ALL A r,&RICAN Gm'[` cHINICAL I 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 though 4. Calculated Factors of Safety are presented in Table 2. I I Table 2. Modeling Parameters and Findings I Analysis Load Across Analysis Initial Positions(Analysis Range) Configuration~JFactor of Number Building Envelope Type Lower U r Radius Auialvzed Safety I Cross-Section A-A' ...... ...... ........... ............ti............. ............ti............................ . I Analysis_I_.__ _-- 1200# :Static :80(]00} :415(100) :365(40) : 125,001 : 2.23 Analysis 2 : ___-___1200t1_______Dynamic :80(100) ___:415000)__365(40)___�_____125.001_ : _ 1.25 -- ------a• ---- - -�--------- ------ I I 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=0.224), the computations demonstrated that the slope is safe and not susceptible to a deep-seated movement. These calculated Factors of Safety (FoS) meet the requirements set forth by Mason County for static conditions (1.50) and meet the requirement(1.10) for dynamic loading scenarios. The site appears stable based on our slope models representing critical slopes at the subject site. As the values inputted were selected to be as conservative as possible,the FoS are likely higher. I The Liquefaction Susceptibility Map of Mason County, Washington by Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann (September 2004) maps the site area as having a Very Low I liquefaction potential. I i 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. Site class C is a very stiff soil or soft rock. GEOSEISMIC SETTING According to the Seismic Zone Map of the United States contained in the 2006 International Building Code (IBC), the project site is located where the maximum spectral response acceleration is 40 percent of gravity(g). We recommend following seismic factors for design purposes. • Site Class: C (Soft Rock) • Spectral response acceleration, short period(SMs): 1.386g(Fa= 1.05) • Spectral response acceleration, 1-second period(Smi): 0.862g(F,= 1.55) • Peak Ground Acceleration(PGA) 0.408g AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 12 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmEkicAN GmTEcHNICAL 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 Silty sand with gravel(SP-SM) • 0 (soil friction angle) 37 degrees • Ko(at rest earth pressure coefficient) 0.40 • Ka(active earth pressure coefficient) 0.25 • Kp (passive earth pressure coefficient) 4.02 7) RESTRICTIONS A) PLACEMENT OF DRAINAGE FEATURES The geology and topography of the site indicates the flow from the residence may be directed away from the residence by downspouts as long as these drain away from the slope. No surface water and no storm discharge of any sort should be directed toward the lower slope. B) PLACEMENT OF SEPTIC DRAIN FIELDS The septic drainfield is located as on Figure 2. C) PLACEMENT OF COMPACTED FILLS AND FOOTINGS RECOMMENDATIONS FOR SITE PREPARATION All areas to be excavated should be cleared of deleterious matter including debris, duff, and vegetation. . Any material that is excavated may be stockpiled and later used for erosion control and landscaping. Otherwise, deleterious material must be removed from the residential site. No dumping should take place in the setback or LHA. If demonstrated to be acceptable, the sand/gravel till material on site may be suitable for re-use as 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. AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 13 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL mERICAN GEOTECHNICAL RECOMMENDATIONS FOR STRUCTURAL FILL 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. 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. For this site, a sample for laboratory testing would be required. D) BUFFERS The residential site as currently planned is within the 50 foot vegetation buffer. As this is a replacement for the current mobile home, and the area was already cleared,this is acceptable. The lower LHA and buffers will not be affected by the proposed manufactured home or other development. E) SETBACKS The replacement of the current mobile home with the manufactured home in keeping with the envelope of Figure 2 will satisfy the geotechnical setbacks. 8) CLEARING AND GRADING PLAN The primary cutting and grading of the site has been done in the area because of the previous on-site residence. "No Disturb"zones will not be required. Further work will be to develop the footings of the structures and improve the road. This is minor in scope. No major grading shall occur. All job site safety issues and precautions are the responsibility of the contractor providing services and/or work. AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 14 Phone#: (360)491-5155 Cell#: (360)481-6677 1 ALL AMERICAN GEoncumcAL I I 9) EROSION CONTROL PLAN 1 It is our opinion that the potential erosion hazard of the site is not a limiting factor for the proposed 1 developments. Removal of natural vegetation has been done at the time of timbering and clearing of the I residential building site. Revegetation as needed should occur immediately following construction if any 1 is required. Any hazard trees may be removed with the roots left in place if possible. I IThe possibility of down-slope contamination is hi Yunlikel if proper control methods are employed. If there is little or no earth-moving, then simple swales or berms may be enough. If there is more, then a silt fence may be required. Work should be one under dry conditions as much as possible. 1 Straw, hay, or jute matting shall be used to cover exposed soils until permanent vegetation is established. I The road cut itself should be protected against the rains and revegetation should be a part of the overall I project. All other denuded slopes should be seeded as soon as practical to facilitate the development of a I protective vegetative cover, or otherwise protected. I A revegetation plan should not be required but may be considered. Densely rooted evergreen shrubs are preferable than tree species on slopes greater than 15% gradient. Tall trees may become unstable in wet soils under high wind conditions. In general, undeveloped steep sides should be left in a natural condition. Please see the erosion notes on Figure 3. This shows the recommended development of a silt fence if needed. The notes on the generic drainage tightline do not apply. 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 building contractor. 11) FINAL DEVELOPMENT CONDITIONS All final conditions will follow the design by the Engineer of Record and compliance with all regulatory agencies. If this and the above recommendations are followed, final development conditions will be achieved. 12) STRUCTURAL MITIGATION The older mobile home is already removed. The pad may be upgraded. 13) SITE PLAN Please see Figure 2. i AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 15 Phone#: (360)491-5155 Cell#: (360)481-6677 l�l ALL A RicAN C rwncHNIC.,AL 1. CONCLUSIONS AND RECOMMENDATIONS Based on the results of our site reconnaissance, subsurface observations, and our experience in the area, it is our opinion that the site is suitable for the proposed project. The construction will not affect the adjacent slopes. Proper drainage control measures will reduce or eliminate the potential for erosion in ( this area. Construction may be performed under most weather conditions. We recommend that earthwork be Cundertaken during favorable weather conditions. Revegetation should be done as per recommendations in the text, above. I PROVISIONS We have prepared this report for the exclusive use of Valeria Gage and her authorized agents for the proposed residence on the Bearcreek-Dewatto Road 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 owners should monitor the stability of the site following construction. Moreover, acceptable Factors of Safety do not guarantee there cannot be failures. It is the responsibility of the property owners association to understand that there are always risks in building 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. I AAG18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 16 Phone#: (360)491-5155 Cell#: (360)481-6677 I I ALL AM CAN GROTWRNICAL 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 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. 1 1 1 1 ' AAG 18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 17 ' Phone#: (360)491-5155 Cell#: (360)481-6677 1 1 I ALL AMERICAN GEOTECKNICAL REFERENCES MAPS 1 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. I 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. I 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. 1 Polenz,K.,and others.,(2009),Geologic Map of the Belfair 7.S-minute Quadrangle, Mason, Kitsap, and Pierce Counties, Washington;Washington State Department of Natural Resources Open File 2009-07. I 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 91441-0, Plate 1, I scale 1:2,000,000. I I PUBLICATIONS I I ASTM International(2005),Annual Book of Standards 2005, Section 4, Volume 4.08,published by ASTM International, West Conshohocken,Pennsylvania. I International Code Council,Inc. (2006),2006 International Building Code,published by International Code Council,Inc. I Kollmorgen Instruments Corporation (1994), Munsell Soil Color Charts (1994 Revised Edition), published by Macbeth Division of Kollmorgen Instruments Corporation,New Windsor,New York. I 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. I 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. I Prakash(1981),Soil Dynamics,Figure 6.3,page 173,published by McGraw-Hill,Inc. ► I Sowers(1979),Introductory Soil Mechanics and Foundations:Geotechnical Engineering,Macmillan Publishing Co.,Inc. 1 I I 1 I I I i AAG 18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 18 i Phone#: (360)491-5155 Cell#: (360)481-6677 i i ALL AMERICAN GEO TECHNIC L WEBSITES Mason County Government Information Services (http://www.co.mason.wa.us) Mason County Codes,Ordinances,and Regulations (http://www.co.mason.wa.us/code) Slope Stabilization Erosion Control Using Vegetation A Manual of Practice for Coastal Bluff (http://www.ecy.wa.govibiblio/9330.html) 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/wac/) Washington Department of Ecology (http://apps.ecy.wa.gov/welllog) (https:Hfortress.wa.gov/ecy/coastalatlas/viewer.htm) AAG18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 19 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICiL 1 APPENDIX USGS Seismic Design Specifications Slope Models Figure 1. Vicinity Map Figure 2. Site Plan Figure 3. Erosion Control Notes r r r r r r r r r r r r AAG18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 20 Phone#: (360)491-5155 Cell#: (360)481-6677 r 1 1 ALL AmERICAN GrmnicnNICAL ' 2009 AASHTO DESIGN SPECIFICATIONS MUM Design Maps summary Report ' User—Specified Input ' Report Title Valerie Gage Mon November 12,2018 12:43:34 UTC Building Code Reference Document 2009 AASHTO Guide Specifications for LRFD Seismic Bridge Design (which utilizes USGS hazard data available in 2002) Site Coordinates 47.493820N, 122.818°W Site Soil Classification Site Class C - "Very Dense Soil and Soft Rock" ' Risk Category I/II/III A Pon aS WG OR 14 VAL TOM Ito SrATY0 N BASE a r b *,� ., .. `r�� • Rf MERTON �,. .. I NATIONA L } tood A►APORT 1i vas rAt �i , r USGS—Provided Output r r PGA = 0.447 g A. = 0.447 g Dean Response Spectrum r S, = 0.988 g Sos = 0.993 g 1 1 S, = 0.351 g Sp, = 0.509 g o.+o OAD o�o y oro • 0M v: 0A0 030 0M 0.10 r om r UAl/ U.3) UAU ULU ,Mi li 1.] I.L Ih IM _i r Period,T Iseel Although this information is a product of the U.S.Geological Survey,we provide no warranty,expressed or implied,as to the accuracy of the data contained therein.This tool is not a substitute for technical subject-matter knowledge. AAG 18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 21 Phone#: (360)491-5155 Cell #: (360)481-6677 I I I� I 2015 IBC DESIGN SPECIFICATIONS 1 U,%S Design Maps summary Report User-Specified Input I Report Title Valerie Gage Mon November 12,2018 12:42:27 UTC 1 Building Code Reference Document 2012/2015 International Building Code r (which utilizes USGS hazard data available in 2008) Site Coordinates 47.493820N, 122.818OW Site Soil Classification Site Class C - "Very Dense Soil and Soft Rock" I Risk Category I/11/III BREUER D1NNEX aAW5os NAVAL NAL h STADM SUBM�R!Nf BR�IFRTON BASF 1 1 - I 1 I � �9�f,IERTON NATIONA L AIRPORT I vas I I USGS-Provided Output I SS = 1.498 g S,75 = 1.498 g SDs = 0.998 9 S, = 0.592 g S., = 0.769 g SDI = 0.513 g Fur information on how the SS and S1 values above have been calculated from probabilistic (risk-targeted)and deterministic ground motions in the direction of maximum horizontal response, please return to the application and select the"2009 NEHRP"building code reference document. I I 111CF t Response Spectrum Ueslip Response Spectrum ILS 14 I!S 04 1 1 J Ors „,i n.]i iJ,i i,bi A Illy 1 T I.In INt IMF ?i1 11„ i, J, i,Yr iib iifi Ir, I.]i I.Y Ib IMF . Peril,T(swo Period,T twe Although this information is a product of the U.S.Geological Survey,we provide no warranty,expressed or implied,as to the accuracy of the data contained therein.This tool is not a substitute for technical subject-matter knowledge. AAG 18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 22 I Phone#: (360)491-5155 Cell#: (360)481-6677 I I ALL A ERICAN GrwTECHNICAL I'- SLOPE MODELS STATIC MODEL A-A'LINE 1 m 1 a cV 1 t_n c6 0—'R U C O m _ s a R C3 N 1 fig_ � � m � 1 U ti I � I 1 � I 1 � I 1 g v 1 c� I 1 0 0 Q I 1 Q � cu Q ¢ �(D U t4 1t 59 S ui c7 �n a AAG 18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 23 1 Phone#: (360)491-5155 Cell#: (360)481-6677 I ' ALL AmEpticAN GE,OTECHNICAL 1 I' DYNAMIC MODEL A-A' LINE tq 3 c" c N r � d � d r ig t � y cn m C) 7S 3 a Qc a W 4 r _ 4 cq Ls r 1 � r g r r r � g r r � r r r a a r - r o LL r3 r Q W Q � � o Q E r A LZ r AAG 18-082 8947 Buttonwood Lane NE, Olympia, WA 98516 24 r Phone#: (360)491-5155 Cell #: (360)481-6677 1 11 111 111 1/1 N 111111 J� g��l� Idf iV1� IMP 1 111 111 111 111 I ALL AMKPtcAN GwTEcHwAL �'• FIGURE 2.SITE PLAN I 1 r C 1 r 1 1 r r 1 I 1 1 1 1 I 1 1 r 1 1 1 1 1 1 1 ► 1 1 1 1 AAG18-082 8947 Buttonwood Lane NE,Olympia, WA 98516 26 1 Phone#: (360)491-5155 Cell#: (360)481-6677 1 GEO Zo I �b- 000le 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: V OL I e v;-c-, Permit#: 0 t 07A Parcel#: 12�bOa1- 31- 9 OV-1 4- Date(s) of the Document(s) reviewed: 2- 3 t-qD 1. (a) A discussion of general geologic conditions in the vicinity of the proposed development, OK? ✓ Comment: (b) A discussion of specific soil types OK? ✓ . Comment: (c) A discussion of ground water conditions OK? ✓ Comment: (d) A discussi n of the upslope geomorphology OK? ✓ Comment: (e) A discussion of the location of upland waterbodies and wetlands OK? ✓ Comment: (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records OK? ✓ Comment: 2. A site plan that identifies the important development and geologic features. OK? ✓ Comment: 3. Locations and logs of exploratory holes or probes. OK? Comment: 4. The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides, and toe)on a geologic map of the site. OK? ✓Comment: 5. A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details of proposed grade changes. OK? '� Comment: 6. A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic safety factor is 1.1 and the quasi-static analysis coeffients should be a value of 0.15. OK?,_Comment: 7. (a) Appropriate restrictions on placement of drainage features OK? `/ Comment: (b) Appropriate restrictions on placement of septic drain fields OK?—i,Comment: (c) Appropriatp restrictions on placement of compacted fills and footings. OK? J Comment: Page 1 of 2 Form Effective June 2008 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. OK? V Comment: (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. OK? Comment: 8. Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. OK? Comment: 9. Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, landslides and harmful construction methods. OK? ✓ Comment: 10. An analysis of both on-site and off-site impacts of the proposed development. OK? `� Comment: 11. Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. OK? ✓ Comment: 12. Recommendations for the preparation of structural mitigation or details of other proposed mitigation. OK? Comment: 13. A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of existing and proposed development on the site. OK? ✓ Comment: Are the Documents signed and stamped? By whom? License#: 24a01, License type: I _t e*K--3s kE-r, C-T rec,I ocJ, s FIRST REVIEW Ef Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by on Z I Time spent in review:7D In� 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 NOTES I ' This is not a survey. This map % / I / is a presentation of - information from county,state,(' ,' /' i ; ,•-' ,,' , Ir and federal agencies,client provided information'and so pt �. onsite observations;for —- -------- discussion purposes of the report with which this map is included. / 101, Site Geology sting Qgie V on glacial ice co deposits FPleistocene) y ' O Site Soil' '' __ _ ' ,' oposed Drain SCALE 1'=60' ,11ai't�Everett v gravelly sand loam, pose RV 4 Parking 8�---- o m b .o 15 to 3 ercent slops 5° efaming Wall iltFencc ,' ,' , / , tl Needed of Wash ,'gyp Q• ,%' �C 2439 ed Goo I Cu Deah Cu man '1• ' All American Geotechnical, Inc. Project Drawn By: Site Plan Permit Number: Parcel Number: 12309-31-90074 Figure 8947 Buttonwood Lane NE Number: B WJ Proposed Single-Family Home Olympia,Washington 98516 AAG18-081 11/28/2018 Belfair, WA Applicant Name: Valerie Gage 419 NE Bearcreek Dewatto Rd 2 PP Site Address: " FILTER FABRIC MATERIAL 60"WIDE ROLLS USE STAPLES OR WIRE RING TO ATTACH FABRIC TO WIRE 2'X2'X14 GAUGE WIRE FABRIC OR EQUIVALENT GENERAL EROSION CONTROL NOTES: 2'-W : : : 1. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIOR TO THE BEGINNING OF CONSTRUCTION. THE PROJECT ENGINEER AND THE COUNTY s'-o /T\ ND SURFACE //,\��: : SHALL INSPECT AND APPROVE THE INSTALLATION OF 1/2 INCH MINIMUM DIAMETER STEEL ROD EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUCTION. (STRAP)CLAMPED SECURELY TO PIPE 2'-6' _, --• • ,,, •- - - ----- -- -- -•:•:• .- 2. EROSION CONTROL MEASURES ARE NOT LIMITED TO THE ITEMS 6'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 4iN7M z i SHALL BE ALLOWED. CARE SHALL BE TAKEN TO PREVENT MIGRATION 2"X4"WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER OF SILTS TO OFF SITE PROPERTIES. JOF BETTER OR EQUAL ALTERNATE: MATERIAL IN 8"X12'TRENCH ciN FFT STEEL FENCE POSTS 3. THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL EROSION C' CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR ADDITIONS TO THE EROSION CONTROL MEASURES. THE CONTRACTOR SHALL PROVIDE ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECESSARY BY THE COUNTY INSPECTOR AND/OR THE PROJECT ENGINEER. FAILURE FILTER FABRIC 6• TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL �i ' ':.': • :`: i:`'?e:\ 'i ='w' 2"X2"X14 GAUGE WIRE REQUIREMENTS MAY RESULT IN CIVIL PENALTIES BEING LEVIED FABRIC OR EQUIVALENT AGAINST THE CONTRACTOR AND/OR PROJECT OWNER. �fy'"a i—" :�iu' ` ='s` h� .'+': {�;•: GROUND SURFACE 5'-0' 4. DURING THE WET SEASON(NOVEMBER TO MARCH)ALL DISTURBED SOILS ;,4•;_. �, r,�,.._ y 1,;.;.,,,.�i:,z�, ; t�.ti:;.gy; SHALL BE STABILIZED WITHIN 48 HOURS AFTER STOP OF WORK. EROSION ` ,;,ty.-;;•?,�.,,.; = >,,.,;.z- PROVIDE 3/4'-1 1!2'WASHE CONTROL MEASURES SHALL INCLUDE,BUT NOT BE LIMITED TO, �",":.�'.y. +^:i` »r�;+. `.h `•.' " D `C::ti.>*'.•.^'h3.:;.:,>,,�'°...:,r.. :•. ;, :;.•.^`'` COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WITH �.=: 'ai+;+; :'•:'a: r .r •r. GRAVEL BACKFILL IN TRENCH 12• AND ON BOTH SIDES OF FILTER PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH, xr ;Y•�; ;>:�. FENCE FABRIC ON THE SURFACE g"MIN OR WOOD CHIPS. SEEDING OF THE DISTURBED AREAS SHALL TAKE PLACE AS WEATHER PERMITS. TIGHTLINE ANCHORED WITH TWO, 2•X4•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 IN A CONTINUOUS ROLL CUT 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 BARRIER TO AVOID USE OF JOINTS. WHEN JOINTS ARE NECESSARY,FILTER CLOTH SHALL BE SPLICED TOGETHER ONLY AT OF THAT WORKING DAY. ANY FURTHER TRACKING OF MUD WILL THEN A SUPPORT POST WITH A MINIMUM 6-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. I 2. POSTS SHALL BE SPACED A MAXIMUM OF 6 FEET APART AND DRIVEN 7. NO MORE THAN 500 LF OF TRENCH ON A DOWNSLOPE OF MORE THAN 5 ` SECURELY INTO THE GROUND(MINIMUM OF 30 INCHES). PERCENT SHALL BE OPENED AT ONE TIME. 3. A TRENCH SHALL BE EXCAVATED APPROXIMATELY 8 INCHES WIDE AND 12 INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER. 8. EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OF TRENCHES. /Cy FLARE END SECTION 9. TRENCH DEWATERING DEVICES SHALL BE DISCHARGED IN A MANNER THAT WILL � QUARRY SPALL '`r•�'=".:::-,'•• 4. WHEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH NOT ADVERSELY AFFECT FLOWING STREAMS. DRAINAGE SYSTEMS OR Z OR ENERGY _•:•;, ,:;:;` '=�-�ti ".' ':,��t -�?' SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE z :: OFFSITE PROPERTIES. DISPERSION DEVICE :t,rt<•;, , �• ='••J. _;:t.;•,x, :asa:: {t OF THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST 1 INCH LONG,TIE WIRES OR HOG RINGS. THE WIRE SHALL EXTEND INTO THE ,. _�:,,.„-:;.c:•.;;,:.; TRENCH A MINIMUM OF 41NCHES AND SHALL NOT EXTEND MORE THAN 36 10.ALL STORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJECT DURING INCHES ABOVE THE ORIGINAL GROUND SURFACE. CONSTRUCTION SHALL BE PROTECTED SO THAT SEDIMENT-LADEN 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 OFF-SITE 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 SHALL BE SEEDED OR SODDED UPON COMPLETION LEVEL SECTION 6. WHEN EXTRA-STRENGTH FILTER FABRIC AND CLOSER POST SPACING IS OF WORK. THE CONTRACTOR SHALL BE RESPONSIBLE TO ENSURE THAT USED,THE WIRE MESH SUPPORT FENCE MAP BE ELIMINATED,IN SUCH COMPLETE COVERAGE OF THE DISTURBED AREAS IS PROVIDED&THAT A CASE,THE FILTER FABRIC IS STAPLED OR WIRED DIRECTLY TO THE GROWTH OF THE VEGETATION IS ESTABLISHED. GEOTEXTILE FABRIC POSTS WITH ALL OTHER PROVISIONS OR ABOVE NOTES APPLYING. 7. 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. 8. 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: Erosion Control Notes 12309-31-90074 Permit Number: Parcel Number: Figure 8947 Buttonwood Lane NE BWJ Proposed Residence Olympia, Washington 98516 11/28/18 Belfair, Washington Valerie Gage Site 419 NE Bearcreek Dewatto Rd Revisions: Applicant Name: e Address: