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Home My WebLink AboutGEO Tech Report - BLD Engineering / Geo-tech Reports - 4/28/2018 Mason County Department of Community Development Submittal Checklist For a Geotechnical Report Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not applicable, the report should explain the basis for the conclusion. C� Applicant/Owner /74 CHF4 (��11/,4Ms Parcel# Site Address 7e" Ly sNccray .t4Ti i of -10 S',61aro d w4 90'nY (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) -7" (b) A discussion of specific soil types Located on page(s) 8-5 (c) A discussion of ground water conditions Located on page(s) 6r (d) A discussion of the upslop geomorphology Located on page(s) (e) A discussion of the location of upland waterbodies and wetlands Located on page(s) q (f) A discussion of history of landslide activity in the activity in the vicinity, as available in the referenced maps and records Located on page(s) (2) A site plan, which identifies the important development and geologic features. Located on Map(s) 9 F/GuAr, L (3) Locations and logs of exploratory holes or probes. Located on Map(s) Fry,►►e 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) �O. �,9 A iY (6) A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst-case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5; the minimum seismic safety factor is 1.1 and the quasi-static analysis coeffients should be a value of 0.15. Located on page(s) /O - %/ (7) (a) Appropriate restrictions on placement of drainage features Located on page(s) /I (b) Appropriate restrictions on placement of septic drain fields Located on page(s) III (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) 12,,, 13 Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) 3 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property '3 Located on page(s) (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.Iq Located on page(s) (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 uand harmful construction methods. Located on page(s) ^T iGJ 3 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 14 (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) f (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. S 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, 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 Washin t w h special knowledge of the local conditions. I also certify that the Geotechnical Report, dated 1 2 D/c4 and entitled w/ul4Ms R6s�Qd rxy 76sy� sy�cr�v uiJ�tcc?i�iZ�meets all the require en of the Mason County Resource Ordinance, Landslide Hazard Section, is complete and true, that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geotechnical design recommendations, and that all hazards are mitigated in such a manner as to prevent harm to property and public health and safety. (Signature and Stamp) hi7 EnpirwrYp a 0« 2439 ow Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. I T G EOTECHNICAL REPORT WILLIAMS RESIDENCE 7654 W SHELTON MATLOCK ROAD SHELTON, WASHINGTON PREPARED FOR RACHEL WILLIAMS BY ALL AMERICAN GEOTECHNICAL OLYMPIA, WASHINGTON APRIL 2812018 ALL A RwAN GiRoTRawicAL CONTACT INFORMATION PREPARER INFORMATION AAG PROJECT NUMBER: AAG 18-016 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: RACHEL WILLIAMS TELEPHONE: (360)485-2162 BILLING ADDRESS: RACHEL WILLIAMS 7654 W.SHELTON MATLOCK ROAD SHELTON,WA 98584 SITE ADDRESS: RACHEL WILLIAMS 7654 W.SHELTON MATLOCK ROAD SHELTON,WASHINGTON PARCEL NUMBER 42018-12-90081 GPS LOCATION: N470 13'41.45" W1230 14' 08.49" (Approximately residence) AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 2 Phone#: (360)491-5155 Cell#: (360)481-6677 ._ Amman GEOTECHNICAL SCOPE OF UNDERSTANDING RACHEL WILLIAMS 7654 W SHELTON MATLOCK ROAD SHELTON,WASHINGTON 98584-8989 RE: GEOTECHNICAL REPORT RESIDENCE 7654 W SHELTON MATLOCK ROAD 00 SHELTON,WASHINGTON N470 13' 41.45" W1230 14'08.49" PARCEL 42018-12-90081 i- APRIL 28,2018 Dear Rachel Williams: Rachel Williams (client) hired All American Geotechnical, Inc. (AAG) in March 2018 to prepare a 00 geotechnical report to comply with the Mason County Requirements in the Critical Areas Ordinance in 00 accordance with the Submittal Checklist For a Geotechnical Report for the above property just off the Shelton Matlock Road in Mason County, Washington. The site is to be developed with a single family residence ADU (Accessory Dwelling Unit) on a low knoll in the northwest part of the property. As per your request, we have conducted a soils exploration and slope stability analysis for the above- mentioned parcel. This is to be in compliance with the requirements of Mason County Planning for a geotechnical report due to potential landslide conditions. We have provided two copies for your review and distribution. Landslide hazards will be detailed in the text. Other geotechnical information is likewise included. 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. (1 r -�, ey Curtis D. Cushman, L.G.,L.E.G. Senior Engineering Geologist 24 Gurus Dean Cuahmant AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 3 Phone#: (360)491-5155 Cell#: (360)481-6677 • ALL AmERICAN GROT RNICA L TABLE OF CONTENTS SCOPE OF UNDERSTANDING 3 INTRODUCTION 6 1) SITE CONDITIONS 6 SURFACE CONDITIONS 6 A) SITE GEOLOGY 7 B) SOIL TYPES 8 C) GROUND WATER CONDITIONS 9 D) UPSLOPE GEOMORPHOLOGY 9 E) UPSLOPE WATERBODIES AND WETLANDS 9 F) LANDSLIDE ACTIVITY 9 2) SITE PLAN 9 3) EXPLORATORY HOLES OR PROBES 9 4) PROPOSED DEVELOPMENT 10 5) CROSS SECTION 10 6) SLOPE STABILTY ANALYSIS 10 SEISMIC LIQUEFACTION HAZARD 1 1 GEOSEISMIC SETTING 1 1 LATERAL EARTH PRESSURES 11 7) RESTRICTIONS 12 A) PLACEMENT OF DRAINAGE FEATURES 12 B) PLACEMENT OF SEPTIC DRAIN FIELDS 12 C) PLACEMENT OF COMPACTED FILLS AND FOOTINGS 12 RECOMMENDATIONS FOR SITE PREPARATION 12 RECOMMENDATIONS FOR STRUCTURAL FILL 13 D) BUFFERS 13 E) SETBACKS 13 8) CLEARING AND GRADING PLAN 14 9) EROSION CONTROL PLAN 14 10) ON AND OFFSITE IMPACTS 14 11) FINAL DEVELOPMENT CONDITIONS 14 12) STRUCTURAL MITIGATION 15 13) SITE PLAN 15 CONCLUSIONS AND RECOMMENDATIONS 15 PROVISIONS 15 GENERAL 15 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 16 READ THESE PROVISIONS CLOSELY 16 AAG 18-016 8947 Buttonwood Lane NE, Olympia,WA 98516 4 Phone#: (360)491-5155 Cell#: (360)481-6677 f 1 ALL ANKRICAN GROTECHNICAL r REFERENCES 17 APPENDIX 19 WELL LOG 20 2009 AASHTO DESIGN SPECIFICATIONS 21 IBC DESIGN SPECIFICATIONS 22 SLOPE MODELS 23 STATIC MODEL A-A' 23 r DYNAMIC MODEL A-A' 24 r FIGURES 25 r FIGURE 1.VICINITY MAP 25 FIGURE 2.SITE PLAN 26 FIGURE 3. EROSION CONTROL NOTES 27 r r r r r r r r r r r AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 5 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL Arnmtcm GawwnmcAL INTRODUCTION This report summarizes the results of our geotechnical consulting services for the proposed ADU on the parcel herein described. The building site is near the northwest part of the parcel. Overall, the property is irregular in topography but descents from the northwest to the south. The property is approximately five miles or so west of Shelton but further by road. The location of the site is shown relative to the surrounding area on the Vicinity Map, Figure 1. Our understanding of the project is based on our discussions with the client. In general, there will be no grading affecting slope stability, being limited to removing loose material, grading the building site, and securing the footings at the construction site well away from the top of the Landslide Hazard Area (LHA). Existing access roads will be improved. The approximate layout of this is shown on the Site Plan, Figure 2. Access to the proposed work site is by private road turning north of W Shelton Matlock Road which is accessed directly from US Highway 101. 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. 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, sampling, and reviewing published well logs. 4. Comparison of the site to published geologic maps, previous field investigations, and open file reports. Inspection of aerial photographs 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 January 1, 2007). 6. Slope modelling. The slope on the north of the building site exceeds a slope of 40% and is greater in height than 10 feet. This areas is within 300 feet of the building site. This is considered a Landslide Hazard Area (LHA) Therefore, Mason County requires that a geotechnical report be prepared in accordance with the Mason County Resource Ordinance Sections 17.01.100 through 17.01.104. 1) SITE CONDITIONS SURFACE CONDITIONS The proposed location for a residence ADU is located near the northwest of the client property. The client property overall slopes irregularly to the south with an east-flowing minor drainage dividing the lower 1/3`a of the property from the rest to the north. The proposed residence will be back-set 27 feet from the top of the LHA. The LHA itself is predominantly to the north of the proposed residence, located on a slope descending to the old railroad line. This slope is approximately 35-feet high and steps down from the top of the ridge to the rail grade. This has a slope of 50%. The overall site elevation for AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 6 Phone#: (360)491-5155 Cell#: (360)481-6677 e ALL AMEBIC.AN GEOTIECHNICAL the entire property ranges from approximately 335 feet in height at the northwest building site, to a low of 275 feet on the east side. The ADU will be built on a previously partially cleared area just above the 330 foot contour. Curtis D Cushman, L.E.G. and Blaise Jelinek E.I.T., conducted a site reconnaissance on March 6, 2018. The purpose of a site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. Subsurface exploration was done by observing exposed soil across the site and in a road cut that goes up toward the site that exposes the column. Visual observations were documented. Site-specific features were mapped. The building site has been cleared of what is seen on the surrounding property as immature second- growth of primarily deciduous trees with a scattering of firs. Property appears to have been logged perhaps thirty or so years ago. There are a few leaners, but most trees are straight and vertical. There is substantial understory which includes native shrubs and berries. No evidence of deep-seated slope instability was observed onsite. The development of the ADU residence is to be partially in the 50' vegetation buffer from the top of the LHA to the north. There is little room elsewhere for the proposed ADU and, as this area is already cleared and will be replanted,the construction should be permitted following the recommendations in this report and all requirements of Mason County. A) SITE GEOLOGY The following is taken from rom the Geologic Map of the Shelton Valley 7.5-minute Quadrangle, Mason County, Washington; by Polenz, M., et al.; 2016; DNR Map Series 2016-02. The deposits all are of the Vashon Stade of the Fraser(continental)Glaciation. Qgic Vashon ice-contact deposits—Daamicton (ablation till,flow till, and poorly compacted or patchy lodgment till), less commonly contains pebble and cobble gravel, sand, mud, and isolated boulders;pale gray, tan, or brown; slightly weathered; compaction, sorting, and stratification vary The materials seen on site are commonly a Poorly graded sand with silt and little gravel. There was no clay seen. (ASTM category SP). This is in keeping with a sub-glacial meltout till in which a bimodal association of fine-grain matrix supports scattered rock clasts. At the south side of the property, below the drainage divide, there is mapped Qgt which is Vashon lodgment till. It is logical to suppose that the overlying diamicton is as described in the Qgic unit. The drilling log for the property at 7652 W Shelton-Matlock Road is adjacent to the client property but below it topographically. The sandy unit is found at a depth of -26 feet. The thick clay layer as described is unlikely in the Qgt deposits and was probably misidentified by the driller. The well, drilled on August 15,2007 shows no near-surface water. This well will be used for the client property. The glacial deposits are typical of tills and are quite compact and suitable for building. The materials at the proposed residence appear to be very stable. AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 7 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmEpttcAN GEoTcnNiL There are no nearby mapped faults and the nearest active fault zone is the Tacoma Fault near Allyn, Washington, to the north. Seismic acceleration is important in modelling the slope stability as the Puget Sound area is in an active tectonic zone and although this fault does not pose an immediate hazard to the proposed building project, low levels of seismic activity are not uncommon. B) SOIL TYPES The soils are described by the USDA Web Soil Survey as: Mason County, Washington Le—Lystair sandy loam, 5 to 15 percent slopes Map Unit Setting • National map unit symbol: 2hm0 • Elevation: 0 to 750 feet • Mean annual precipitation: 60 to 90 inches • Mean annual air temperature: 48 to 50 degrees F • Frost-free period: 140 to 170 days • Farmland classification: Farmland of statewide importance Map Unit Composition • Lystair and similar soils: 100 percent • Estimates are based on observations, descriptions, and transects of the mapunit. Description of Lystair Setting • Landform: Outwash plains, kames • Parent material: Outwash or sandy till Typical profile • H1 - 0 to 4 inches: ashy sandy loam • H2 - 4 to 16 inches: ashy sandy loam • H3 - 16 to 60 inches: sand Properties and qualities • Slope: 5 to 15 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 of flooding: None • Frequency of ponding: None • Available water storage in profile: Low (about 5.0 inches) Nd—Norma sandy loam, 0 to 3 percent slopes The soil map shows this at the building site. In slope, composition, and source, this mapping is incorrect. AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 8 Phone#: (360)491-5155 Cell #: (360)481-6677 ALL AMERICAN GROTECHNICAL The soil is well-drained and the depth to the restrictive layer is over 80 inches. The soil is not important to the construction of the ADU. The soil is shallow and development will remove it to the underlying glacial deposits. The residential construction will occur within the 50 foot vegetation buffer. The soils elsewhere on the property and off-property will not be disturbed. C) GROUND WATER CONDITIONS The property is divided by a natural drainage that is not perennial. It opens to the east. While ' appreciable in size, it is not deeply incised and has a limited capture basin. There was no evidence of ' active surface erosion above this feature. The nearest base level appears to be Goldsborough Creek some 3000 feet to the south. Ground water will not be a problem at the building site. D) UPSLOPE GEOMORPHOLOGY There is none to speak of as the building site is on a ridge. There are some higher slopes over 1000 feet to the north, but these are not much higher than the ridge at the building site and there is a valley in between. These pose no geotechnical hazard to the property. E) UPSLOPE WATERBODIES AND WETLANDS ' There are none. F) LANDSLIDE ACTIVITY The Shelton Valley 7.5-minute quadrangle shows no landslide near the building site and none along the ' entire ridge system it is located on. LiDAR from the Puget Sound Lidar Consortium(g47123b21be) shows no evidence of landslides. Indeed, the low glacially sculpted and eroded topography shows no nearby slopes susceptible to large-scale mass ` wasting. On site,there was no evidence of current or potential landslide activity. r 2) SITE PLAN r The proposed ADU is located on Figure 2. This is represented by an acceptable building envelope. The r geology is overall Qgic. The soil boundary is shown, but it is not correct when viewed in the field. 3) EXPLORATORY HOLES OR PROBES r The site was surface examined and at a deep perc pit,roughly at the residence location. Sample location for field evaluation is as shown on Figure 2. r r AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 9 r Phone#: (360)491-5155 Cell#:(360)481-6677 r ALL AMEMCAN GEOTECHNICAL 4) PROPOSED DEVELOPMENT Figure 2 shows the required features of: proposed developments, the boundaries of the hazard (LHA), and associated buffers and setbacks. 5) CROSS SECTION Two(2)cross-sections are in the Appendix. They are along line A-A' which includes the building site. 6) SLOPE STABILTY ANALYSIS The Slope Stability Analysis is as follows following the Mason County Resource Ordinance of 2009: 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 [dynamic] safety factor is 1.1 and the quasi-static analysis coefficients should be a value of 0.15. Slope stability was modeled using the GALENA 6.1 program in both static and dynamic conditions (ca = 0.205). "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. Factors of safety were determined using the Bishop (semi-circular) method. The site was modeled a single layer. The parameters are provided in the output in the appendix. A ground water table was not included in the model. The spread footings were included in the models, represented as the continuous load of 1500 pound across the footprint of the house in the model. The models represent the steepest slopes in the vicinity of the residence and the steepest slopes on property. Density is considered to be 1081bs per cubic foot, common for sand deposits. The material is classified as a soft rock. The material encountered was an SP-- poorly graded clean sand, sand-gravel mix. Based upon the classification, the following values were assigned: cohesion of 0 lbs per square foot and phi angle of 37 degrees were selected as conservative values for Qgic in the model. r Testing a range of failure circles identifies the worst-case scenario: therefore, the initial parameters in the A-A' in a model with a total length of 232 feet, the initial location for a failure at the toe was set at 115 feet, the building location runs from 184 to 215 with a continuous load, the initial location for the top failure was 200 feet, and the initial radius is 85 feet. These initial positions were tested over a range of 50 feet, 40 feet, and 30 feet respectively; with 50, 50, and 50 positions tested over the ranges. Our computations in both the Static and Dynamic condition analyzed at least 125,001 possible failure circles for each case. The graphical output of this data is presented in the appendix. AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 10 Phone#: (360)491-5155 Cell#: (360)481-6677 Under static conditions, the slope generally did not show susceptibility to deep failure that would cause damage to the proposed residence. See Appendix for model output and cross-sections. Under dynamic loading (Ca=0.205), the computations demonstrated that the slope is safe and not susceptible to a deep- seated movement. The following are the Factors of Safety (FoS) attained for the section with respect to its current topographical representation. Soil Parameters: Wei ht 108#,Cohesion 0,4D Anj Ile 370 Analysis Factor of Safe Static Factor of Safety ODynamic) A-A', 3.20 1.71 ' These calculated Factors of Safety (FoS) meet the requirements set forth by Mason County that is, 1.50 for static and 1.1 for dynamic loading scenarios. Thus, based on our slope models representing critical slopes at the subject site, it is apparent that the building site is not susceptible to damage by deep-seated movements or instability. The values input were selected to be as conservative as possible so the FoS are likely higher. This analysis shows this particular site to be stable. No other slopes qualified as Landslide Hazard Areas. SEISMIC LIQUEFACTION HAZARD 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 liquefaction potential. The Site Class Map of Mason County, Washington by Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann(September 2004)maps the area as site Class C. 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 45 percent of gravity(g). We recommend following seismic factors for design purposes. • Site Class: C (stiff soil/soft rock) • Spectral response acceleration, short period(SMs): 1.445g(Fa= 1.05) • Spectral response acceleration, I-second period(Smi): 0.780g(F,= 1.55) 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: AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 11 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL A MERICAN GEOTECHNICAL • (soil friction angle) 37 degrees • Ko (at rest earth pressure coefficient) 0.398 • Ka(active earth pressure coefficient) 0.249 • Kp(passive earth pressure coefficient) 4.02 • y(soil unit weight) 108 pcf 7) RESTRICTIONS A) PLACEMENT OF DRAINAGE FEATURES The site is naturally drained away from the proposed ADU site as it is to be located on the top of a ridge. All ground surfaces, pavements and sidewalks should be sloped away from the residence and associated structures. Surface water runoff should be controlled by a system of curbs, berms, drainage swales, and/or catch basins and tight lined into the appropriate drainage facilities. No surface water should be directed specifically toward the bluff to the north and in general toward any steep slope. We recommend that conventional roof drains be installed. Footing drains shall be installed for the proposed structure. The roof drain should not be connected to the footing drain. For footing drains, the drain invert should be below the bottom of the footing. Typical drainage control measures are included on Figure 3 in the appendix. Figure 3 shows recommendations for a tightline which is possibly a viable option for this property if water can be disposed of after a drop to a natural drainage. The design of the drainage system is the responsibility of the Engineer of Record. B) PLACEMENT OF SEPTIC DRAIN FIELDS The drain fields are proposed for an area northeast of the residence. This is an acceptable location as it is away from the LHA and the water well. Please refer to 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 any existing structures, debris, duff, and vegetation. All deleterious material will be removed and sub-soils reached for the footings for the construction of slab and/or footings. Any material that is excavated may be stockpiled and later used for erosion control and/or landscaping. Surficial material unsuitable for these tasks should be removed from the project site. No foundation elements shall be constructed on"untested"fill material. AAG 18-016 8947 Buttonwood Lane NE,Olympia,WA 98516 12 Phone#: (360)491-5155 Cell#: (360)481-6677 A- LL AMERICAN GR®TacnNi C` L 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. 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. 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. The on-site material may be suitable for structural fill. D) BUFFERS The 50-foot vegetation buffer from the top of the LHA will be intruded upon by the proposed ADU residential construction. However, the footprint would be minimal and it likely could be built without major disturbance of the trees and low growth shrubs and vines. There likely will be no further removal of trees for the residence as the area was already timbered. Specific hazard trees were not identified at the time of the site visit, but these may be removed from the property if they meet Mason County definitions for hazard trees. E) SETBACKS The residential site is well outside of the hazards as defined by the slope stability model and the resultant Factors of Safety. AAG 18-016 8947 Buttonwood Lane NE,Olympia,WA 98516 13 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL A EpicAN GKoumnNicAL 1 8) CLEARING AND GRADING PLAN Some final clearing is needed for the residence. This will not be extensive or intensive. "No Disturb" zones will not be required. There will be no major grading. 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. Removal of natural vegetation at the ADU residential site will be limited to final clearing and will be away from the LHA. Trees and understory growth on the slope will not be disturbed for the residence. Revegetation as needed should occur immediately following construction. Some trees near the LHA may be considered hazard trees and subject to removal. Roots should be left in place. The possibility of down-slope contamination is highly unlikely if proper control methods are employed. A silt fence may be installed as shown on Figures 2 and 3. At the building site, other control methods, such as swales and baled straw are practical. No re-contouring of the site will occur. Surface drainage should be directed away from all slope faces. Straw, hay, or jute matting shall be used to cover the exposed soils until permanent vegetation is established. All slopes should be seeded as soon as practical to facilitate the development of a protective vegetative cover, or otherwise protected. A revegetation plan should not be required. When residential plantings or any plantings on the periphery . of the residential area and the slopes are planned, native species should be considered as the primary r vegetation in areas away from lawn and ornamental plantings. Shallow rooted species, such as grass, should be planted closer than 10 feet from underground drainages. 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, the bluff should be left in a natural condition unless erosion or sloughing eventually pose a hazard to the property. 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 high standards and practices of the building contractor. i No geotechnical impact is anticipated in the construction of the ADU residence. 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. AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 14 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmEmcm GEoTKcnNtcAL 12) STRUCTURAL MITIGATION There is none. 13) SITE PLAN Please see Figure 2. CONCLUSIONS AND RECOMMENDATIONS Based on the results of the site reconnaissance, subsurface observations, and our experience in the area, it is our opinion that the site is suitable for the proposed project. The proposed ADU residence location is stable relative to deep-seated instability and will not be affected by the proposed structure. The proposed structure does not undermine adjacent slopes. Proper drainage control measures will reduce or eliminate the potential for erosion in this area. The site will lie within the 50 foot vegetation buffer. But as it has been almost fully cleared, the buffer may be intruded upon as long as the landslide setback is observed and all necessary measures are taken to prevent erosion during construction and after the ADU is in place. Revegetation, if needed, should be done immediately following completion of work. PROVISIONS GENERAL We have prepared this report for the exclusive use of Rachel Williams and her authorized agents for the proposed development 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, while a slope may be found to have an acceptable Factor of Safety related to deep-seated mass wasting, surficial failure and landslides can and do occur on steep slopes. The property owners should monitor the stability of their property following construction. Moreover, acceptable Factors of Safety do not guarantee there cannot be failures. It is the responsibility of the property owners to understand that there are always risks in building on or near steeply sloped areas. AAG 18-016 8947 Buttonwood Lane NE,Olympia,WA 98516 15 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AM CAST GROTMANICAL 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 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 Aregarding a specific project. AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 16 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEoTEcnNtcAL REFERENCES MAPS DeLorme 3-13 TopoQuads(2002),Source Data USGS,Yarmouth,Maine. 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. Polenz, M., et al. (2006) Geological Map of the Shelton Valley 7.5-minute Quadrangle Mason County, Washington — Northwest Quadrant(DNR Map Series 2016-12),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 91441-0, Plate 1, scale 1:2,000,000. Washington State Department of Ecology (1979), Coastal Zone Atlas of Washington, Volume 9, published by Washington State Department of Ecology. PUBLICATIONS Ambrose(1981),Simplified Design of Building Foundations,Table 2.5,pages 48-57,published by John Wiley&Sons, Inc. ASTM International(2005),Annual Book of Standards 2005, Section 4, Volume 4.08,published by ASTM International, West Conshohocken,Pennsylvania. Bloom(1991),Geomorphology,published by Prentice-Hall, Inc.,Upper Saddle River,New Jersey. Gallagher, Patricia M. (October 27, 2000), Passive Site Remediation for Mitigation of Liquefaction Risk, Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University,Virginia. 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. McCarthy(1993), Essentials of Soil Mechanics and Foundations, published by Prentice-Hall, Inc., Upper Saddle River, New Jersey. 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. Prakash(1981),Soil Dynamics,Figure 6.3,page 173,published by McGraw-Hill,Inc. Sowers(1979),Introductory Soil Mechanics and Foundations: Geotechnical Engineering,Macmillan Publishing Co.,Inc. Washington State Department of Transportation(WSDOT)(2005), Standard Specifications for Road, Bridge, and Municipal Construction 2006 M41-10,prepared by WSDOT Engineering Publications,P.O.Box 47408,Olympia,Washington. AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 17 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL Amr,&RICAN GrmTEcHNICAL 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) Puget Sound Lidar Consortium (http://pugetsoundlidar.ess.washington.edu/lidardata/index.html) Slope Stabilization Erosion Control Using Vegetation A Manual of Practice for Coastal Bluff (http://www.ecy.wa.gov/biblio/9330.html) Vegetation Management Guide for Puget Sound Bluff Property Owners (http://www.ecy.wa.gov/biblio/933 l.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/weillog) (https:Hfortress.wa.gov/ecy/coastalatlas/viewer.htm) AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 18 Phone#: (360)491-5155 Cell#: (360)481-6677 r ALL AMnICAN GROTWA ICAL APPENDIX Well Log USGS Seismic Design Specifications Slope Models Figure 1.Vicinity Map Figure 2. Site Plan �I �I AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 19 Phone#: (360)491-5155 Cell#: (360)481-6677 WELL LOG CURU WATER WELL REPORT NobiX17IrNent No 161141130 f t't o t a c r Ongmal&lsl copy Ecology,tad copy owner, id copy driller Unique Ecology Well 1D Tag No AG6 S41�/ Constnlclfontl3ecorrisnissm(j'in circle) ri Construction Water Right Permit No Lkconurussion ORIGINAL CONSTRUCTION Notice 12.21411 of hueru Number Property Owner Name�r4 CN/i4EL !�/�-�-/A r►r $ PROPOSEDUSE Domestic industrial Well Street Address /A47ZQCX de(AOrIL ❑DeWater ❑lmgauon ❑TestWeli ❑Other City y4r1 ELToN County llrt ASDAJ PE OF WORK Owners number of well(if more than one) `�� EWM CIA New Well ❑Reconditioned Method ❑Due ❑Bored ❑Driven Location�l/4 U4 Q'=114 Sec Twq�NR ran ❑Deepened ❑Cable Rotary ❑Jetted Lat/Lon pp (s,4r still DegLa[MirJSec DIMENSIONS Diameter of well__-inches drilled�Lft Depth of completed well_41T_ft REQUIRED) Long Deg tong Mtn/Sec CONSTRUCTION DETAILS Tax Parcel No "ZO/o—/Z pO0a0 Casing KWcldcd Diam from it to 40ft CONSTRUCTION OR DECOMMISSION PROCEDURE Installed ❑Lmer mstaaed Diam from ft to it Formation Descnbe by color,character,size of material and structure and the kind and nature of the material in each stratum penetrated,with at last one ❑Threaded Diam from ft to_____ft entry for each change of information Indicate all water encountered Perforations ❑Yes WNo (USE ADDITIONAL SHEETS IF NECESSARY) Type of perforator used MATERIAL FROM TO SIZE of perfs_m by—in and no of pats—from ft to—ft Screens WYes ❑No ❑K-Pac Location rN /v /✓ Manufacturers Name er,O Type- [ / oriel No L [Nam & Slot Siu from ilrdo ft to ft Mum Slot Size—from—ft to ft GraveUFdter packed ❑Yes JRNo ❑size of gravel sand Matenals placed from ft to ft — /Yl LvT Lp/O� Surface Seal ;$Yes ❑No To what depth" TO It Materials used in seal jgrAl-r-w.'re- Did any strata contain unusable water? Oyes ArNo Type of watery Depth of strata Z Method of sealing strata off PUMP MaouGcturersName 44 W S9r G Type Sub H P Z WATER LEVELS Land surface elevation above mean sea level ft L.�/1rIlN S� Static level Sp ft below top of well Date /e—3—O 7- Artesian pressure Ibs per square inch Date — Artesian water is controlled by G (ca,valve,etc) W ELL TESTS Drawdown is amount water level is lowered below static level Was a pump test made?❑Yes ;no If yes,by whontl Yield gal/con with ft drawdown after hrs Yield ¢al/min with ft drawdown after hrs RECEIVE Yield at/min with ft drawdown after hrs Recovery data(rime taken au zero when pump turned of(water level men%uredjrom well top to water level} Time Water Level Time Water Level Time Water Level _ Wa%htnaton State DeDaitnient of ECOi Date oof test Bauer test 1/nun with ft drawdowo after z tics Airtest cal/min with stem set at ft for hrs Artesian flow ¢p in Date— Temperature —�•-O Z ��— yZ Temperature of water—Was a chemical analysis made Yes ❑No Sun Date Completed Date WELL CONSTRUCTION CERTIFICATION 1 constructed and/or accept responsibility for construction of this well,and its compliance with all Washington well construction standards Materials used and the information reported above are true to my best knowledge and belief Driller ❑Engineer❑Trainee Name( DnllmgCoompany I-e-/N7 Dnller/Engtneer/Trainee,Stgnat Address/ Q,Ae �3 Duller or Traunce License No 'Z' City,State,Zip EASTD A�/19 DG'r4 `j ,EKp it trainee,licensed dnHer's Contractor's Ny'/Y)$A-j92jZj� ,,�=/Is-OZ Signature and License no Ecology is an Equal Opportunity Employs ECY OSO I.20(Rev 4/Ol) AAG18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 20 Phone#: (360)491-5155 Cell #: (360)481-6677 2009 AASHTO DESIGN SPECIFICATIONS rg= Design Maps Summary Report User-Specified Input Report Title Rachel Williams Tue April 24,2018 14:48:56 UTC Building Code Reference Document 2009 AASHTO Guide Specifications for LRFD Seismic Bridge Design (which utilizes USGS hazard data available in 2002) • Site Coordinates 47.228180N, 123.2357QW Site Soil Classification Site Class C - "Very Dense Soil and Soft Rock" Risk Category I/II/III TM AVO 10, 01 .n Sh4dtm IRA MERV VI USGS-Provided Output PGA = 0.410g As = 0.410g Design Response Spectrum SS = 0.912 g Sos = 0.944 g 1 10 Im S, = 0.366 g Sol = 0.525 g o.eo oIn Obi 0.9 Oi[ OJO Q.S O.W 0M OAO 0.30 OAO OW 020 Im I.I, IAo 120 1>D 2DD Paioi.T(m) 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 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 21 Phone#: (360)491-5155 Cell #: (360)481-6677 ALL AmERICAN GmucHNICAL IBC DESIGN SPECIFICATIONS NJ= Design Maps Summary Report User-Specified Input Report Title Rachel Williams . Tue April 24,2018 14:47:05 UTC Building Code Reference Document 2012/201S International Building Code (which utilizes USGS hazard data available in 2008) Site Coordinates 47.228180N, 123.2357°W Site Soil Classification Site Class C -"Very Dense Soil and Soft Rock" Risk Category I/II/III a .f USGS-Provided Output Ss = 1.445 g Sins = 1.445 g Ss = 0.963 g Sl = 0.600 g S", = 0.780 g Sol = 0.520 g For 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. NICE.Response Spectrum Desk Response Spectrum "A' u�,.i �» all. 1.3, I.Y. I", In. Pelsd.T rune Pt .T wwo Although this information is a product of the U.S.Geological Survey,we provide no warranty,expressed or impheed,as to the accuracy of the data contained therein.This tool is not a substitute for technical subject-matter knowledge. AAG18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 22 Phone #: (360)491-5155 Cell #: (360)481-6677 ALL AramcAN GRoTacnNicAL SLOPE MODELS STATIC MODEL A-A' O U N p � to cd CO w a W C!) A X o T Cn m U g R m 4 N N O m (00 O N O O m CD O �mmP �yyyq dg Ch O E O N Z = c w ;R O _j E R� o C2. fE Se S 3 JU U AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 23 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL Ammcm Gr6oTr6cnNtcAL DYNAMIC MODEL A-A' W Q in m dCID V a m = v� $8 m U ti a I 0 0 O N m O Y O N O O 1 m O (O } Cp @C �l J N Q L' o J h 2 ss o F E pp pp 00 ccpo pN .% cc R M M m CMN U O AAG 18-016 8947 Buttonwood Lane NE,Olympia, WA 98516 24 Phone#: (360)491-5155 Cell #: (360)481-6677 ALL Ammcm GrwTEcHNICAL FIGURES FIGURE 1.VICINITY MAP 123116'00"W 123'15'00'W 123a14'00'W WGS84 123a13'00'W F-• ..aY16NT e I On �••i . E I .• p O' � � ,� � 1 •� z z ., q4- 2e = 1 - I t 5 t i. a tiE - Coghtt =h Inks_ lake -f r - r 12 2 01 I 1 Lc Fropos ces iorb ng 76-5,M he ton ck and s ' 1 r , _ 6 I _ i. J i \�'•' ��\ .mot a a i 123-16 00"W 123°15'00"W 123°14'00'W WGS84 123'13'00"W 0 WA t-IMFEET t=�._�_ Y„_,�IOODNEIEMS Ptmted&=TOPO'C:OD1 NSt."C,,gaphw H.Iduti+!axu-.top.tom p AAG18-016 8947 Buttonwood Lane NE,Olympia,WA 98516 25 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL Ammcm GKorEctiNicAL FIGURE 2.SITE PLAN AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 26 Phone#: (360)491-5155 Cell#: (360)481-6677 ' ALL AundcAti GEoTKcnNt L r FIGURE 3. EROSION CONTROL NOTES ► ► r r r M ► r r r r r ► r r r r r r r r 1 ► AAG 18-016 8947 Buttonwood Lane NE, Olympia, WA 98516 27 ► Phone#: (360)491-5155 Cell#: (360)481-6677 r '3011 ounda NO S This is of a survey. This map is a pres tation of informati n from county, state,and feder agencies,client provided i ormation,and onsite observati s; for discussion purposes of e report with which this map i cluded. ' e Geolo 386.50' g,c--Vas ice itact depos Nd Q� Site So' o Le Nd Norma sandy loam c 0 to 3 percent slopes v° `A d y ta' ciiiii y oa 5 cen s opes Le i a y loam e c 10� 5 to p cent pe ai a �' helton gr v lly s ndy loa .S 5 to 1 r nt opes So`� x en Se xist eId ra am I � � P po ed - U Sf ¢ 2a3� a 2 _ Icuft Cuslx Driv 00 SCALE 1* W O M M M V� M OI c.a.=s c^ c^ in o zo ao eo so M M cr1 M M Cn O N N I 536. ' All American Geotechnical, Inc. Project Drawn By: Site Plan Permit Number: Parcel Number: 42018-12-90081 Figure 8947 Buttonwood Lane NE Number: BWJ Proposed Accessory Dwelling Unit Olympia, Washington 98516 AAG18-016 4/26/2018 Shelton, WA Applicant Name: Rachel Williams Site Address: 7654 W Shelton Matlock Road 2 FILTER FABRIC MATERIAL 60"WIDE ROLLS USE STAPLES OR WIRE RING TO ATTACH FABRIC TO WIRE 2'X2'X14 GAUGE WIRE n rFABRIC OR EQUIVALENT n GENERAL EROSION CONTROL NOTES: 2'-0' : : : : 1. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIOR TO THE . . BEGINNING OF CONSTRUCTION. THE PROJECT ENGINEER AND THE COUNTY 5'-0' /�\ 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 7�• ------- - --------- ------------------- 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 L J NO SILTATION OF EXISTING OR PROPOSED DRAINAGE FACILITIES SHALL BE ALLOWED. CARE SHALL BE TAKEN TO PREVENT MIGRATION <.""=: . OR Miiy�Mv 2"X4"WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER OF SILTS TO OFF SITE PROPERTIES. O 7 F BETTER OR EQUAL ALTERNATE: MATERIAL IN 8'X12'TRENCH y�,`c:s`:•'i?;�^;r;.-. SpgC/H STEEL FENCE POSTSl'»"_ 3. THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL EROSION CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR ADDITIONS ,;>.;. '>'• v..:, .. ;:;�.,. TO THE EROSION CONTROL MEASURES. THE CONTRACTOR SHALL PROVIDE ;,,•: _ _.,,y._�,"�3•;;wi;.::�=,^a�;;;=.:, ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECESSARYBY THE COUNTY INSPECTOR AND/OR THE PROJECT ENGINEER. FAILURE �'>s�!S`?•_:- i�'?;;'�:ti: r>S FILTER FABRIC 6' TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL ' '` �'='-�<-.....,,.,,. -"'='•�.,,1-:•.;Y':-. �':T-:::, REQUIREMENTS MAY RESULT IN CIVIL PENALTIES BEING LEVIED t` t; ry.•' :`•' ?-:�`+'';'r�i=:;? r' 2'X2'X14 GAUGE WIRE i' �:_'I"' ";_: %n:•_ . FABRIC OR EQUIVALENT AGAINST THE CONTRACTOR AND/OR PROJECT OWNER. GROUND SURFACE 514' 4. DURING THE WET SEASON(NOVEMBER TO MARCH)ALL DISTURBED SOILS ,:•,,.,.:-�.a �,z r''^'",�'1 -' '�-. ;,:•-i }:.',;w;:,q.�c ,• ::5��•";y`,y>:.�• SHALL BE STABILIZED WITHIN 48 HOURS AFTER STOP OF WORK. EROSION y`. 4 r �' ~.` •`r a'r•;-� •_,-rt•.'i•_>� PROVIDE 3/4'-1 1/2'WASHED CONTROL MEASURES SHALL INCLUDE,BUT NOT BE LIMITED TO, ':" •,ati' .+" "'' •.j>?r r'. "`'! `\�! �'i.�:4vv;i:.:.... .M:`�-�`::a.,t-.>• ::;` :�:•:`. GRAVEL BACKFILL IN TRENCH COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WITH tee_.�� t>i:;:•;%<r,>.;a;+f^ >' 12• �� S„�y;k ,:_ :' `•- AND ON BOTH SIDES OF FILTER PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH, • -..,1�,,-; „s.� i'_ ' FENCE FABRIC ON THE SURFACE OR WOOD CHIPS. SEEDING OF THE DISTURBED AREAS SHALL TAKE �' '`'' "`=•!` 8"MIN 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: 6. TRACKING OF SOIL OFFSITE WILL NOT BE ALLOWED. IF ANY SOIL IS 1. FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO TRACKED ONTO A COUNTY STREET,IT SHALL BE REMOVED BY THE END THE LENGTH OF THE BARRIER TO AVOID USE OF JOINTS. WHEN JOINTS OF THAT WORKING DAY. ANY FURTHER TRACKING OF MUD WILL THEN A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELYELY ARE NECESSARY,FILTER CLOTH SHALL BE SPLICED TOGETHER AT 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 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 8. EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OF TRENCHES. Cy FLARE END SECTION INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER. QUARRY SPALL 9. TRENCH DEWATERING DEVICES SHALL BE DISCHARGED IN A MANNER THAT WILL is' •-ate 4. WHEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE OR ENERGY NOT ADVERSELY AFFECT FLOWING STREAMS. DRAINAGE SYSTEMS OR OF THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST 1 INCH OFFSITE PROPERTIES. DISPERSION DEVICEh4ti?�a;. ;+{•v, LONG,TIE WIRES OR HOG RINGS. THE WIRE SHALL EXTEND INTO THE " `�K,-,; ': >, sc'v:.•� w.':`.�`•'r`�`-. TRENCH A MINIMUM OF 4 INCHES 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 BOTTOM AND ONE FOOT DEEP WITH INTO THE TRENCH. THE FABRIC SHALL NOT EXTEND MORE THAN 36 11.ALL OFF-SITE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE A MAXIMUM SLOPE OF 5 PERCENT. INCHES ABOVE THE ORIGINAL GROUND SURFACE. FILTER FABRIC SHALL SHALL BE PROTECTED FROM SILTATION. 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 42018-12-90081 Figure Proposed Accessory Dwelling Unit Permit Number: Parcel Number: g 8947 Buttonwood Lane NE BWJ P ry g 4/26/18 Shelton, Washington 3 Olympia, Washington 98516 g Applicant Name: Rachel Williams Site Address: 7654 W Shelton Matlock Road Revisions: