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HomeMy WebLinkAboutGEO2017-00044 2019-00018 - GEO General - 4/1/2019 GE02 C, 1"7 - Mason County Review Checklist for a Geotechnical Report Instructions: This checklist is intended to assist Staff in the review of a Geotechnical Report. The Geotechnical Report is reviewed for completeness with respect to the Resource Ordinance. If an item is found to be not applicable, the Report should explain the basis for the conclusion. The Report is also reviewed for clarity and consistency. If the drawings, discussion, or recommendations are not understandable, they should be clarified. If they do not appear internally consistent or consistent with the application or observations on site, this needs to be corrected or explained. If resolution is not achieved with the author, staff should refer the case to the Planning Manager or Director. Applicant's Name: UY\ci1;V- C1� Permit#: K 2 _fly c) yyParceI#: I Zl Z 2- � �_C11 c'U 7_6 Date(s) of the Document(s) reviewed: S1 -1 (2x) 1 -1 1. (a) A discuson of general geologic conditions in the vicinity of the proposed development, OK? `/ Comment: 41 -16 (b) A discussi�4 of specific soil types OK? V Comment: 11 (c) A discussio of ground water conditions OK? v Comment: I2 (d) A discussio of the upslope geoorphology OK? V m Comment: i 2 (e) A discussio f the location of upland waterbodies and wetlands OK? Comment: 1.Z VVA,;_ (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records OK? \,/ Comment: �W r ' ', 2. A site plan that identifies the important development and geologic featur s. OK? ,,/` Comment: 2- 3. Locations and logs of exploratory holes or probes. OK? Comment: 2 � 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 Qf site. -n L OK? ✓ Comment: 2- h V1 !�`f 1 VL4 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: '2'1 '3 6. A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic safety factor is 1.1 and the quasi-static analysis coeffients should be a value of 0.15. OK? `,// Comment:13 15 7. (a) Appropriate restrictions on placement of drainage features OK? ✓ Comment: IS (b) Appropriate estrictions on placement of septic drain fields OK? T Comment: 'C S N/•Pr (c) Appropriat?restrictions on placement of compacted fills and footings. OK? V Comment: t5 '(U Page 1 of 2 Form Effective June 2008 eO 2.017- 00 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. Applicant/Owner l Aundr� 13i'L. (ri.,-.ti,: 'iss oc Parcel# `/2/zZ -/Z — c ZC- Site Address T (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 3-10 (b) A discussion of specific soil types Located on RECEIVED (c) A discussion of ground Water conditions Located on page(s) /� kR $ 9 2��� (d) A discussion of the upslope geomorphology Located on page(s) /1, (e) A discussion of the location of upland waterbodies and wetlands 615 W. Alder Street Located on page(s) 1 J. (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) j, Z- (3) Locations and logs of exploratory holes or probes. Located on Map(s) i 4 w 2-- (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) j,7, r=i4,j<ld '4 (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) I�, z,� - 3 (6) A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst-case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5; the minimum seismic safety factor is 1.1 and the quasi-static analysis coeffients should be a value of 0.15. Located on page(s) 3— 7 (7) (a)Appropriate restrictions on placement of drainage features Located on page(s) /,:$7 (b) Appropriate restrictions on placement of septic drain fields Located on page(s) lS (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) 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) _ / Z- - (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property., 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. Located on page(s) /G 7 (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, landslides and harmful construction methods. Located on page(s) . 17 (10) An analysis of both on-site and off-site -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) 1-7 (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) (13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of existing and proposed development on the site. Located on Map(s) I, lc�2ris C���tii 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 tha the Geotechnical Report, dated ?-"y -lG l? and entitled Z&,/T_f fir!. � hir, 1 e1` meets all the requirements 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) Wesh�� � 0 troop3 24 Curtis__Dean Cushman]Page 2 of 2 _. Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. • • 0 0 RECEIVED 0 GEOTECHNICAL REPORT JUL 9 2011 • EAGLE POINT DRIVE 0 THUNDER RIDGE OWNERS' ASSOCIATION • SHELTON, WASHINGTON • 0 0 • PREPARED FOR 0 THUNDER RIDGE OWNERS' ASSOCIATION 0 0 • BY 0 ALL AMERICAN G EOTECHNICAL 0 OLYMPIA, WASHINGTON 0 i 0 i JULY 14, 2017 0 0 • i • 0 0 • t • 0 • • 0 • ALL AMEPICAN GMTECHNICAL • CONTACT INFORMATION 0 PREPARER INFORMATION AAG PROJECT NUMBER: AAG17-042 i CONTACT: CURTIS D.CUSHMAN A • i 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: THUNDER RIDGE OWNERS'ASSOCIATION BILLING ADDRESS: THUNDER RIDGE OWNERS'ASSOCIATION PETER STEWART,TREASURER P.O.Box 755 SHELTON,WASHINGTON 98584 SITE ADDRESS: E.EAGLE POINT DRIVE SHELTON,WASHINGTON PARCEL: 42122-12-00020 GPS LOCATION: N470 17'57.60" W1230 10' 22.96" CONTACT: JASON ZACH TROA PRESIDENT TELEPHONE: (360)490-6711 i EMAIL ADDRESS: JASONZACK@COMCAST.NET i AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 2 • Phone#: (360)491-5155 Cell#: (360)481-6677 �I • ALL AmERic AN GTEOTECHNICAL SCOPE OF UNDERSTANDING JASON ZACK,PRESIDENT TROA P.O.BOX 755 • SHELTON,WASHINGTON 98584 RE: ROAD CUT GEOTECHNICAL REPORT E EAGLE POINT DRIVE SHELTON,WASHINGTON N470 17' 57.60" W 123010'22.96" PARCEL42122-12-00020 . JULY 14,2017 Dear Mr. Zack: Jason Zack, site property owner and president of the Thunder Ridge Owners' Association (TROA), hereafter "client;" hired All American Geotechnical, Inc. (AAG) in June 2017 to prepare a geotechnical report for a section of E Eagle Point Drive located on the property of Mr. Jason Zack north of Shelton, Washington. This is in keeping with a requirement of Mason County. The site is undeveloped at this time with the exception of Eagle Point Road which crosses it. The pre-existing road is failing along its northeastern edge and will require remediation in the form of cutting away its southern bank to expand the road away from the area of maximum failure. The intent of this project is to evaluate the landslide hazards associated with remediating the road and evaluate the impact on the hillside. The south bank will be cut back to set the road back from the edge of the failing slope. • 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 three copies for client review and distribution. AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 3 • Phone#: (360)491-5155 Cell#: (360)481-6677 A • - ALL AMERICAN GEOTECHNICAL • • Detailed contouring of the immediate site and remedial engineering of the road-cut is provided by the ` Engineer's Report for Thunder Ridge Owners' Association (MY) prepared by Marley Young, P.E. of Shelton, Washington dated August 5, 2008. A geotechnical report was prepared by Geotechnical Testing Laboratory of Olympia, Washington titled Subsurface Soils Investigation for Marley Young(GTL) signed • by Curtis D Cushman L.E.G., L.G., and dated July 3, 2008 (signed and stamped July 7, 2008). • We appreciate this opportunity to be of service to you and we look forward to working with you in the 0 future. If you have any questions concerning the above items,the procedures used, or if we can be of any 0 further assistance please call us at the phone number listed below. Respectfully Submitted, • ALL AMERICAN GEOTECHNICAL,INC. i �a��'of ash; f • Curtis D. Cushman, L.G., L.E.G. Senior Engineering Geologist Engineenng Geologist • �/C 2439 \yam • e�Sed Ge • Curtis Dean Cushman • • 0 • 0 • • 0 4 • • • • • I* AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 4 0 Phone#: (360)491-5155 Cell#: (360)481-6677 • 0 0 • ALL Am1 - GEOTECHNICAL 0 0 TABLE OF CONTENTS • INTRODUCTION 7 0 1) SITE CONDITIONS 8 SURFACE CONDITIONS 8 A) SITE GEOLOGY 9 • B) SOIL TYPES 1 1 C) GROUND WATER CONDITIONS 12 D) UPSLOPE GEOMORPHOLOGY 12 E) UPSLOPE WATERBODIES AND WETLANDS 12 F) LANDSLIDE ACTIVITY 12 • 2) SITE PLAN 12 i 3) EXPLORATORY HOLES OR PROBES 12 ' 4) PROPOSED DEVELOPMENT 12 5) CROSS SECTION 13 6) SLOPE STABILTY ANALYSIS 13 7) RESTRICTIONS 15 A) PLACEMENT OF DRAINAGE FEATURES 15 B) PLACEMENT OF SEPTIC DRAIN FIELDS 15 M C) PLACEMENT OF COMPACTED FILLS AND FOOTINGS 15 RECOMMENDATIONS FOR SITE PREPARATION 15 RECOMMENDATIONS FOR STRUCTURAL FILL 16 RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL 16 D) BUFFERS 16 E) SETBACKS 16 8) CLEARING AND GRADING PLAN 16 r 9) EROSION CONTROL PLAN 17 0 10) ON AND OFFSITE IMPACTS 17 11) FINAL DEVELOPMENT CONDITIONS 17 12) STRUCTURAL MITIGATION 18 13) SITE PLAN 18 CONCLUSIONS AND RECOMMENDATIONS 18 • PROVISIONS 18 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 19 READ THESE PROVISIONS CLOSELY 19 REFERENCES 20 APPENDIX 22 2009 AASHTO DESIGN SPECIFICATIONS 23 SLOPE MODELS 24 AAG17-042 8947 Buttonwood Lane NE,Olympia, WA 98516 5 • Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNIC AL • STATIC MODEL FAILURE BELOW ROAD EXISTING CONDITIONS 24 DYNAMIC MODEL FAILURE BELOW ROAD EXISTING CONDITIONS 25 ` STATIC MODEL FAILURE ABOVE ROAD EXISTING CONDITIONS 26 DYNAMIC MODEL FAILURE ABOVE ROAD EXISTING CONDITIONS 27 STATIC MODEL FAILURE BELOW ROAD AFTER ROAD CUT 28 DYNAMIC MODEL FAILURE BELOW ROAD AFTER ROAD CUT 29 STATIC MODEL FAILURE ABOVE ROAD AFTER ROAD CUT 30 • DYNAMIC MODEL FAILURE ABOVE ROAD AFTER ROAD CUT 31 FIGURES 32 FIGURE 1.VICINITY MAP 32 FIGURE 2. SITE PLAN 33 FIGURE 3. EROSION CONTROL NOTES 34 • AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 6 Phone#: (360)491-5155 Cell#: (360)481-6677 r ALL AmEwAN GEOTECHNICAL INTRODUCTION This report summarizes the results of our geotechnical consulting services for the road remediation herein described. The proposed remediation is on E Eagle Point Drive approximately 1.7 miles from State Route 10 on the Jason Zach property just east of 991 E Eagle Point Drive. The site is approximately 5 direct miles north-northwest of downtown Shelton, Washington. 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 president Mr. Jason Zack, the client treasurer, Mr. Peter Stewart, and reference to the reports of 2008 by Marley Young and Geotechnical Testing Laboratory. In general, this will be a project involving cutting back of an existing road bank and subsequent improvement of the road. The approximate layout of the site is shown on the Site Plan, Figure 2. The purpose of our services is to evaluate the surface and subsurface conditions at the site in order to satisfy the requirements of the Mason County Critical Areas Ordinance, and as a basis for providing geotechnical recommendations and design criteria for the project. All American Geotechnical is therefore providing geotechnical services for the project. Specifically, our scope of services for this project includes the following as needed: 1. A review of the available geologic, hydrogeological and geotechnical data for the site area. i 2. A geologic reconnaissance of the site area and surrounding vicinity. 3. Investigation and identification of shallow subsurface conditions at the site by characterizing the exposed soil, reviewing published well logs, and sampling. 4. Comparison of site to published geologic maps, previous field investigations, and open file reports. Inspection of aerial 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. 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 northeast side of the road. This is local failure with a slope of greater • than 40% with a height over 10 feet. Therefore, Mason County requires that a geotechnical report be i prepared in accordance with the Critical Areas Ordinance. AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 7 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GKOTECHNICAL 1) SITE CONDITIONS SURFACE CONDITIONS • As recorded in the 2008 report by Marley Young, the northeast side of E Eagle Point Road at the location cited above is failing along a stretch of perhaps up to 250 feet in length. This is due to the construction of • the gravel road along a steep hillside. At this location,the road is too close to the northern drop off and is down-slumping. The shoulder failure mentioned by Mr. Young is now a suite of failures and potential failures, some with several feet of recently-occurring down-drop. Mr. Young also cites the effects of rain • contributing to the failure seen in 2008. In the wake of a wet winter in 2016-2017, this notion may also . explain some or even much of the recent failures; however, the hillside steepness alone and heavy vehicle use are also important factors. The road here proceeds northwest-southeast with the drop off down to the 0 northeast, the road being cut into the bank to the southwest. The site exposure is to the northeast. Site ' elevations range for the Zack property extends from approximately 60 feet above msl in the north to over 360 feet forming a broad ridge-top. The road is roughly along the 330-foot contour. z T <xF h � Overhanging Maferial . �•+f y J+� W S x.. t � r t The site was visited by Curtis Cushman L.E.G. and Blaise Jelinek E.I.T. on June 22, 2017. The client was 0 on site with his son, Wilson, as was Mr. Stewart, treasurer and former president of TROA. The purpose i of a site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. A site map was prepared identifying features of the property. Surficial r exploration and inspection of outcrops was done. The GTL report contains the results of the boring tests 0 done at the time with their laboratory analyses. Visual observations were documented and site-specific features were mapped. 0 0 0 AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 8 . Phone#: (360)491-5155 Cell#: (360)481-6677 i ALL AKKp,1CANG1&oTECHNtC,AL The proposed road improvement is on a relatively steep slope underlain by glacial deposits. There is no extreme topography above the project site although there is a sloughing feature that will be detailed, below. No surficial water is present. The edge of the road is 4 collapsing locally, but much of the i f roadbed appears firm. No active s aY e w erosion was seen. , The LiDAR map to the right is a bare earth depiction of the property. The road failure is at the head of the large drainage extending to the north. The semi-circular feature to = the south is mapped as mass wasting ' but does not appear to affect the area Vt of immediate concern. The slope is vegetated with mature and juvenile trees, notably evergreens, and various varieties of native plants. Trees are predominately straight and vertical. The road cuts,through a landslide hazard area(LHA). The top of the proposed cut will be near the top of the LHA and a vegetation buffer will extend 50 feet up the slope. The vegetation buffer is well vegetated with existing trees. While it is unusual to evaluate an up-slope vegetation buffer from below,the removal of trees and other vegetation will occur mainly in the upper end of the LHA and most, if not all, of the buffer will remain intact. Thus,the impact of this development is minimal. s 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. The site of the failure, however, exposes pre-Fraser deposits derived from the Olympics. 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. i The Geologic Map of the Skokomish Valley and Union 7-5-minute Quadrangle, Mason County, Washington Open File Report 2010-03 by Polenz, Michael and others (revised 2011), published by the Washington Division of Geology and Earth Resources) maps the site as follows: M • 8947 Buttonwood Lane NE, Olympia, WA 98516 9 AAG 17-042 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL QPuPo 0 . Pre-Fraser Olympic-source glacial and nonglacial deposits—Gravel, sand, silt, clay, and diamicton, including tills and paleosols; tan to reddish brown or gray; compact;poorly sorted. These compacted sediments are seen as bluff-forming where undisturbed, such as in the road cut. Their variation is seen in the auger holes (GTL)but the poorly-sorted nature of the sediments (well-graded on the lab reports) is in keeping with the map description. Immediately above the area is a large semi-circular feature described as: • QMW Mass wasting deposits—Cobbles,pebbles, sand, silt, clay, boulders, and diamicton; generally unsorted, i but locally stratified; loose; shown along potentially or demonstrably unstable slopes. These unusual deposits, many linear or arcuate in nature, are commonly, but not always, associated with steep slopes. Their main characteristic of note in this area is their loose nature. On the immediate flanks of the Qpuop and above and below most of the Qmw are the common units described as follows: i Qgik 41 Vashon ice-contact kames and kame deltas—Gravel, sand, and some silt; mostly loose; medium to very thickly bedded or massive; moderately to well stratified. These are deposits of glacially scoured material that collect upon the glacial ice to be left behind following the glacial melting retreat. The contact with the underlying Qpuop is locally ill-defined, often due to vegetative cover. This uncertainty is expressed on Figure 2 as question marks along the upper contact. The face of the road-cut and the laboratory results indicate the section is in the Qpuop. This unit was covered by thick glacial ice and is well compacted as a result. It possibly underlies the road elsewhere along its length beneath a veneer of kames deposits. The undisturbed material is generally quite good for construction and under most circumstances would not have major problems supporting a road such as E Eagle Point Drive. AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 10 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmERIc GEOTECHNICAL B) SOIL TYPES The soil at the road is: Sh—Shelton gravelly sandy loam, 30 to 45 percent slopes Map Unit Setting National map unit symbol. 2hn3 Elevation: 100 to 800 feet • Mean annual precipitation: 50 to 70 inches Mean annual air temperature:48 to 50 degrees F Frost-free period: 150 to 180 days • Farmland classification: Not prime farmland Map Unit Composition Shelton and similar soils: 100 percent • Estimates are based on observations, descriptions, and transects of the mapunit. Description of Shelton Setting Landform: Moraines Parent material: Basal till with volcanic ash Typical profile H1 - 0 to 3 inches:very gravelly medial loam H2- 3 to 27 inches.very gravelly medial sandy loam H3-27 to 60 inches:very gravelly sandy loam Properties and qualities Slope: 30 to 45 percent Depth to restrictive feature: More than 80 inches; 25 to 36 inches to densic material Natural drainage class: Moderately well drained Capacity of the most limiting layer to transmit water(Ksat):Very low to moderately low (0.00 to 0.06 in/hr) Depth to water table:About 24 to 36 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile:Very low(about 2.2 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated):6e Hydrologic Soil Group: A Hydric soil rating: No This is a common soil for the area and is derived from specific glacial materials. It is not relevant to the engineering of the road. It is important for erosion control that I not be removed outside the project area. AAG17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 11 Phone#: (360)491-5155 Cell #: (360)481-6677 ALL AmERICAN GEOTECHNICAL C) GROUND WATER CONDITIONS No surface water flow was observed on site. There was no evidence of springs on the slope. The drainage to the north is important as the failure is at its head. D) UPSLOPE GEOMORPHOLOGY The slope to the southwest flattens out to form part of a broad highland. A knoll at just over 380 feet is to the west-southwest of the road failure site, and to the southeast is a plateau at over 440 feet in elevation, approximately 2000 feet away. These pose no hazard. E) UPSLOPE WATERBODIES AND WETLANDS There are none. S F) LANDSLIDE ACTIVITY The Skokomish/Union 7.5-minute quadrangle shows the area to be of limited mapable landslides. Most of these are relatively small failures in the lowermost part of the bluffs lining the south side of the Skokomish River valley. There is one large slide approximately due east of the project site, and it appears associated with a large steep drainage. The hill-side and slopes qualify as a landslide hazard area,but the factors of safety for the road at the project site will be discussed, below. �► 2) SITE PLAN The proposed location of remediation is shown on Figure 2. The geology is Qpupo as noted, and the other units are mapped. There is no well or septic involved in the road remediation. 3) EXPLORATORY HOLES OR PROBES Sample locations were from north of the road. See figure 2. Hand samples for this report were from the road cut. The locations and laboratory results are in the 2008 GTL report. 4) PROPOSED DEVELOPMENT Figure 2 shows the required features of: proposed remediation, the boundaries of the hazard (LHA), and associated buffers and setbacks. The Young report has the engineering details. AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 12 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHNICAL i 5) CROSS SECTION Eight(8) cross-sections are in the Appendix along line A—A'. 6) SLOPE STABILTY ANALYSIS As noted above,there are some mapped landslides in the area. LiDAR shows no signs of major landslides in the immediate area. There is a history of local landslides primarily along the base of the bluff along the Skokomish River. There was no evidence of significant recent erosion observed onsite at the time of • our investigations. The failure of the roadside appears local and does not indicate deep failure. 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 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 steep nature of the slope along with the effects of traffic are destabilizing the edge of E Eagle Point Road. Following construction of the road remediation, encouraging vegetation and discouraging runoff from the i 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 with S two layers of material; our field exploration did not find the two material to be different within our area of investigation. The parameters used in this modeling were based on experience with the surroundings and the types of materials encountered on site, and laboratory result from the GTL 2008 report. A ground water table was not included in the model based on our site investigation. Dynamic road loading was not applied to the model. Slope stability was modeled using the GALENA 6.1 program in both static and dynamic conditions (ca= 0.208). "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. AAG l 7-042 8947 Buttonwood Lane NE, Olympia, WA 98516 13 r Phone#: (360)491-5155 Cell#: (360)481-6677 i ALL AmERICAN GEOTECHNICAL The soil was laboratory classified in the range of an SW-SC Well-graded sand with clay. The sample was collected at about 8-feet below ground surface from boring H-2. This classification required a model that mixes the material, selecting conservative values in the interests of safety. The site was modeled as two similar units. The material in the current road cut best fits the description of . the Pre-Fraser Olympic-source glacial and nonglacial deposits (Qpuop), as seen in the road cut. Above . the proposed road cut is the Vashon ice-contact kames and kame deltas (Qgik); this unit is included as a cap on the model. The geologic units at the lower end are not relevant to the analysis and are not included on the cross-sections. The units were modeled using the following soil parameters presented in Table 1. Geologic Unit Modeled Values. Table 1. Geologic Modeling Values • FGeologic Unit :Unit Weightl Cohesion phi angle p 120 22530 ..........................................:..........................;......................... 120 225 30 Eight (8) different analysis were calculated along the A-A' line, itemized on Table 2. Modeling iParameters and Findings. The Analysis Number corresponds to the output presented on pages 24-31. The slope was modeled in the existing condition (Pre) as well as after the road cut (Post). Initial positions were selected based upon the road as the point of concern. The initial points were varied over the analysis range indicated; with 100 different positions tested across these ranges. A total of 1,000,001 calculations were performed for each analysis. Table 2. Modeling Parameters and Findings raysis . Analysis Initial Positions (Analysis Range) Configuration Factor of Pre/Post y i ber Ty Lower Upper Radius Calculated Safety € Pre Static € _524 (55) = 775 (50) 180 (50) 1,000,001 1.60 ..................................................................................:.......................... .......................... .................................:............. .......... ....... P.e..... ..Dynamic 524.(55).. 775.(50}.. 180.(50).. 1:000,001.... 1:�..... Pre Static 524 (55) 895 (50) 350 (_50) 1,000,001 1.83 • ...... Pre..... ..Dynamic 524 (5`5_>.. 895.(50).. 350 (50).. 1,�0.1.... 1:14..... ..........:.....................;......................:...........................:....... ..Post = Static = 524 (55) 781 (50) = 180 (50) 1,000,001 1„62 .........:..................... ......................{..................... ...q..................... q..................... ....p..................... ....... ...............Post Dynamic 524 (55) 781 (50) 180 (50) 1,000,001 1.06 ..........:.... ...................................... ........... .......... ....................... ...... . .Post Static 524 (55) 895 (50) 350 (50) € 1,000,001 = 1.84 ......... �...................... �.......... .............. t.......................... Post Dynamic :: 524 (55) 895 50) 350 (50) 1,000,001 1.14 0 i Under static conditions, the slopes generally did not show susceptibility to shallow failure that would i cause damage to the road. Under dynamic loading (Ca=0.208), the computations demonstrated that the upslope is safe and not susceptible to a deep-seated movement. The down slope as modeled was found to be less than 1.1 under dynamic conditions before (1.04) and after (1.06) the road improvement. This AAG17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 14 e Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICA.N GEOI L means that, as we know, the lower part of the slope has a higher possibility of failure than the entire road • or the upslope area. These calculated Factors of Safety (FoS) meet the requirements set forth by Mason County for static conditions (1.50); but fall just short (1.1) for dynamic loading scenarios on the lower slope analysis. • Calculated Factors of Safety are presented in Table 2. Based on our slope models representing critical • slopes at.the subject site, it is apparent that the road is susceptible to damage by deep-seated movements or instability under dynamic (earthquake) conditions. The values input were selected to be as conservative as possible so the FoS are likely higher. 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 to Low liquefaction potential. The Site Class Map of Mason County, Washington by Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004) maps the site area as site Class C to D. Site class C is a very stiff soil or soft rock and Class D is stiff soil. 7) RESTRICTIONS A) PLACEMENT OF DRAINAGE FEATURES Drainage design is incorporated into the road design, involving ditching along the base of the proposed 0 road-cut at the base of the cut slope. All ground surfaces, pavements and sidewalks should be sloped . away from the bluff. Drainage from above will be removed by the road ditch. B) PLACEMENT OF SEPTIC DRAIN FIELDS This is not applicable to this site and this report. C) PLACEMENT OF COMPACTED FILLS AND FOOTINGS a 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 at the time of the earth-moving to grade the new part of the road. Any material that is excavated may be stockpiled and later used for erosion control. Otherwise, the material must be removed from the site.No dumping should take place. If demonstrated to be acceptable, the sand/gravel till material on site may be suitable for re-use as structural fill. AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 15 Phone#: (360)491-5155 Cell#: (360)481-6677 • ALL AmERWAN GEOTrACHNICAL . 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" 49 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. i 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 i (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. No compacting or fill is foreseen. The following notes are for completeness in case some fill is required: • The site material appears from the 2008 GTL lab reports to be suitable for structural fill. Such use would S require compaction testing. D) BUFFERS The site is a LHA. The buffer upslope will not be disturbed although following the earth-moving, it will have a different final contour. This should not inhibit construction of the road. I There is no lower end of the LHA marked on Figure 2 as it is not relevant to this project. • E) SETBACKS There is no geotechnical setback for this development. 8) CLEARING AND GRADING PLAN This is an earth-moving and grading project, following the design recommendations of Young and GTL. 0 The primary cutting and grading of the slope will be such that few trees will be disturbed, The area above the new road cut should be graded to insure no loose material (such as the Qmw noted in AAG17-042 8947 Buttonwood Lane NE,Olympia,WA 98516 16 • Phone#: (360)491-5155 Cell#: (360)481-6677 i ALL AMERICAN GEOTECHNIC AL • "Geology, above) sloughs onto the road Grading may also be done to reduce the slope immediately r above the new road-cut. "No Disturb" zones will not be required. All job site safety issues and precautions are the responsibility of the contractor providing services and/or • work. The following cut/fill slope guidelines are provided for planning purposes. The project will produce a cut slope. The geology and the history of the road indicates the cut slope will be stable and safe to work around in place as long as basic safety measures are observed. 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 will be restricted to the new road cut along with removal • of overhanging duff, loose material and hazard trees. Revegetation as needed should occur immediately following construction. Upslope hazard trees may be removed with the roots left in place if possible. • The possibility of down-slope contamination is highly unlikely if proper control methods are employed. A silt fence and some other control methods, such as swales are not practical. Work should be one under dry conditions and the downhill slope protected by loose hay or bales of hay. Straw, hay, or jute matting shall be used to cover exposed soils until permanent vegetation is established. The road cut itself does not require reseeding, but all other denuded 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. 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 steep sides of the ravine should be left in a natural condition. Please see the erosion notes on Figure 3. The silt-fence section is not recommended for this project and the drainage section is also not part of this project. i 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. i 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. This section of the road is to be monitored as the drainage canyon it is located next to will i erode in its natural course. AAG17-042 8947 Buttonwood Lane NE, Olympia,WA 98516 17 Phone#: (360)491-5155 Cell#: (360)481-6677 i i 1 ALL A Ep,1CAN GEOTECHNICAL 1 . 1 12) STRUCTURAL MITIGATION There is none. 13) SITE PLAN . Please see Figure 2. 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. Although the proposed road widening is located in a known landslide hazard area,the proposed road widening will not undermine adjacent slopes. ion in this area. Proper drainage control measures will reduce or eliminate the potential for eros Work may be performed under most weather conditions. We recommend that earthwork be undertaken during favorable weather conditions. Revegetation should be done as per recommendations in the text, above. i The improved road may be considered as suitable for two-way traffic. However, all heavy vehicles may the le should avoid the northeast side of the road at all times. This the require e t narrowing g This should reduce . lane, or having directions to all drivers to stay away from g vibration and excessive weight. PROVISIONS • We have prepared this report for the exclusive use of Thunder Ridge Owners' Association and their road improvements on Eagle Point Drive in Mason County, authorized agents for the proposed and mapping have culminated in this report. This report is Washington. Site inspections, research, intended to meet the requirements of the Mason County aeagle tre Ordinance. s setbacksnor specify setbacks for: line-of-sight setbacks, FWHCA s tbacks property line setbacks. Within the limitations of scope,es in the field of geotechni al engineering in this i executed in accordance with generally accepted practi 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 road following construction. AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 18 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AmaRlcAN GaOTECHNICAL / 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 steeply sloped i areas. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS • not intended to direct the contractor's. procedures, methods, Our geotechnical recom mendations are schedule or management of the work site. The contractor is solely rend toe for job site adjacent properties.and for . managing construction operations to minimize risks to onsite personnel 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 • (g ate unrealistic lead to disciplines. This lack of understanding can creGeotechnicaleCincludes t these at uexplanatory disappointments, claims and disputes. All American . "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 or +* engineering or geologic reporting does not usually relateyundergroundtal storagenganks orlusions regulated d • recommendations; e.g., about the likelihood of encountering ironmental reports are not used to address geotechnical or geologic concerns contaminants. Similarly, env regarding a specific project. i • i • i • • i • • • • • . 19 AAG 17-042 8947 Buttonwood Lane NE,Olympia, WA 98516 Phone#: (360)491-5155 Cell#: (360)481-6677 • r ALL Ammc&N GEOTECHNICAL REFERENCES 1 M MAPS DeLorme 3-D TopoQuads(2002),Source Data USGS,Yarmouth,Maine. Drag ovich, Logan, Walsh, and Schasse(2002), Geological Map of Washington—Northwest Quadrant(Geological Map GM- 50),published by Washington State Department of Natural Resources. . Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann (September 2004), The Liquefaction Susceptibility Map of Mason County, Washington, published by Washington State Department of Natural Resources. Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004), The Site Class Map of Mason County, Washington,published by Washington State Department of Natural Resources. Polenz,M.,et al.(2012),Geologic Map of the Skokomish Valley County, Washington;Washington State Department of Natural Resources DNR OF 2010-03 (Revised 2011) • W. J., and Priest, G. R. (1996), Map showing known or suspected faults with Rogers, A. er Walsh, l J., ent in man, published b U.S. Geological Survey OFR 91-441-0, Plate 1, quaternary displacement in the Pacific Northwest, p y M scale 1:2,000,000. Smith, Carson (1977), Relative Slope Stability of the Southern Hood Canal Area, Washington, prepared in cooperation with the Washington Department of Natural Resources Division of Geology and Earth Resources; and,Department of the Interior United States Geological Survey. • PUBLICATIONS • ook of Standards 2005, Section 4, Volume 4.08,published by ASTM International, West ASTM International(2005),Annual B • • Conshohocken,Pennsylvania. International Code Council, Inc.(2006),2006 International Building Code,published by International Code Council,Inc. a Kolor Charts (1994 Revised Edition), published by Macbeth ollmorgen Instruments Corporation (1994), Munsell Soil C • Division of Kollmorgen Instruments Corporation,New Windsor,New York. A Soil ion Service, in ation Ness,Fowler, he United ted St,The Soil Survey f and Wasason County, h gton Agricultural Experimental Station, and the rSoils with the United States Department oAgriculture, 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 .,Inc. : Geotechnical Engineering,Macmillan Publishing Co 2005 Standard Specifications for Road, Bridge, and Municipal Washington State Department of Transportation (WSDOT) ( ), ering Publications,P.O.Box 47408,Olympia,Washington. Construction 2006 M41-10,prepared by WSDOT Engine • WEBSITES • Mason County Government Information Services • (http://www.co.mason.wa.us) 20 • AAG17-042 8947 Buttonwood Lane NE, Olympia,WA 98516 Phone#: (360)491-5155 Cell#: (360)481-6677 r r ALKERjaxN OIECHA r r . Mason County Codes,Ordinances,and Regulations r (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.govibiblio/9330.html) Vegetation Management Guide for Puget Sound Bluff Property Owners • (http://www.ecy.wa.govibiblio/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://fortress.wa.gov/ecy/coastalatlas/viewer.htm) • . AAG 17-042 8947 Buttonwood Lane NE,Olympia, WA 98516 21 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL A ERIGE(OTECHNICAL 1 1 _ ' APPENDIX r r r USGS Seismic Design Specifications • Slope Models Figure 1.Vicinity Map • Figure 2. Site Plan Figure 3. Erosion Control Notes • • • • • • • • • • • • i • • • • • • • 8947 Buttonwood Lane NE, Olympia, WA 98516 22 AAG17-042 Phone#: (360)491-5155 Cell#: (360)481-6677 • • r ALL AM, , ERIc AN HNICAL 2009 AASHTO DESIGN SPECIFICATIONS r rrjUM Design Maps summary Report User-Specified input Report Title Eagle Point HOA Fri July 7,2017 18:42:29 UFG ications for Building Code Reference Document 00K#9i AA u es hazard data Guide availablem 20fl;RFD Seismic Bridge Design (wh utilizes • Site Coordinates 47.2990N, 123.17°W Site Soil Classification Site Class D -'Stiff Soil' • Risk Category I/II/III r a • Sf+s C'LDS 114 Ti�'N • • • I oil • SANDERS C{Ft +�P OIL) Sh ei ton • USGS-Provided Output • PGA = 0.415 g As = 0.450 g Desogn Response Spectrum • SS = 0.919g Sps = 1.041g S, = 0.361 g Sol = 0.606 g ate' i a 0 an • 35 • 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. • • WA 98516 23 AAG17-042 8947 Buttonwood Lane NE, Olympia, Phone 4: (360)491-5155 Cell 4: (360)481-6677 • • ALL Aml&pjcxN GEOTECHNICAL SLOPE MODELS STATIC MODEL FAILURE BELOW ROAD EXISTING CONDITIONS • co g R --! N -- �, 2 Q E `) �, cs3 •" R � in v� � O 3 . m Ecc • .m a ¢ cI V w a • o • • • o n o • i i i • i i 8cs Lu cc lL • 6 o R S • • WA 98516 24 AAG 17-042 8947 Buttonwood Lane NE,Olympia, Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTECHN'CAL 1 DYNAMIC MODEL FAILURE BELOW ROAD EXISTING CONDITIONS � N U o = o td N N CV C6 O . h 2 m CJ coo U j @ o t � a • 0 • • • o • o • • • o • • • a • • N C _� N � � o Q .cu og' cu o m .g 5. • Z rn o • o E B • o 0 0 0 0 0 ~ c� • CO O U • 25 Cell #: (360)481-6677 • AAG17-042 8947 Buttonwood Lane NE, Olympia, WA 985 Phone 4: (360)491-5155 • • 1 ALL AMERICANTIL 1 STATIC MODEL FAILURE ABOVE ROAD EXISTING CONDITIONS F1 ® F � T � la N v C� R m � § m g� o � .oc T9 � � 1 M c� • x � w W w W Q g cs" a co c o CD r o ca o m N � • m Q � g S U � _ U O li • i 8947 Buttonwood Lane NE, Olympia,WA 98516 26 17 AAG -042 Phone#: (360)491-5155 Cell#: (360)481-6677 1 ALL EIGIEOTECIINIC,ALL 1 DYNAMIC MODEL FAILURE ABOVE ROAD EXISTING CONDITIONS i {{ N v' .r.92 T N t G a ti g ¢ n c� O • m r 0 N h � y -191 $ U nn Q ci • • o o o • • .Q ca .9�,,� 3 o Q lL c w cr- � LL E Q O O • • 8947 Buttonwood Lane NE,Olympia,WA 98516 27 AAG17-042 Phone#: (360)491-5155 Cell#: (360)481-6677 1 t ALL AMERICAN GEOTECHNICAL 1 STATIC MODEL FAILURE BELOW ROAD AFTER ROAD CUT cccli r r a ca _ 1B N • o d� m U C0 LL • 6 o • � o • • • • • • m m o m m •- g M • S 8 8 S 0 g � 17 • • AAG 17-042 8947 Buttonwood Lane NE, Olympia,WA 98516 28 Phone#: (360)491-5155 Cell#: (360)481-6677 • • ALL ANEWCAN GROTIECHNIC-AL 1 DYNAMIC MODEL FAILURE BELOW ROAD AFTER ROAD CUT Tli2 ca Q];Ito �sA ao U • �o-' • • • o • o c� • • o • • • • • r= 0oo a-' • N 9 O q� i 7� -f�5 m E � N N F • z ' o � � • - co : • s s g 17 s ~ � Lr ii • O AAG 17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 29 Phone#: (360)491-5155 Cell#: (360)481-6677 • • • 1 ALLAMIERICAt4 GEOTIECHNIC 1 STATIC MODEL FAILURE ABOVE ROAD AFTER ROAD CUT [4 � �a cn CJ. E ,� ?• d . F651 m in a4 %_- oW) mWoL 4 • • • VENOM 8 • o d � • • • • • • � c Ern a Q � � • cD u ' N Y c • s $ s g o CD CZ Z • tC1 O U O • • 8947 Buttonwood Lane NE,Olympia, WA 98516 30 AAG17-042 Phone#: (360)491-5155 Cell#: (360)481-6677 • • • 1 1 DYNAMIC MODEL FAILURE ABOVE ROAD AFTER ROAD CUT N g Ecd c W c m g c o CC L N_ � la o tp U • a-3I i !b g ci Cal 6 w d s7— • o 0 a • �i • i ! o • • �° .E a a o � e U C5 a 41 cc ¢ LL qc7 23'e • s � a o o 0 0 i CD . 8947 Buttonwood Lane NE, Olympia,WA 98516 31 AAG17-042 Phone#: (360)491-5155 Cell#: (360)481-6677 • • 1 AN Gr WIfECHNIC AL FIGURES FIGURE 1.VICINITY MAP 123°1V00'W WGS84 123°09'00'W 12301200'W -123011'00"-W �� .\ ►- i�-.�. e a L° <.s ,....., I tyr' r' ^_ir✓ +r � �-,,._9 rw•` . �f �� ` /.�w�r.."•O I � /�/" :�/ '—?��,.� ..'�..=+,. ,,,,�.�s. IBM17.3 8M23.8 -' I �.9G -,.... � ate. 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X I .d ,<_y ur � ��a�Y� I �'m.s=�� o�n�} u w `,.°i • n © t e� i s a® " I WL 1 J WGS84 123°09'00'W • 123°11'00"W 123°30'00"W rune 123°12'00"W p s TN* NN p®00KET p =0D N)0A METERS • ��16�i`° Pantedfram T0P0!02001?,.t mdo papxH&dt%-(a'av'.t°pomm) e NE, Olympia,WA 98516 32 AAG17-042 8947 Buttonwood Lan Phone#: (360)491-5155 Cell#: (360)481-6677 1 1 ALLAMWRIC AN E 1 , FIGURE 2.SITE PLAN • • • • • • • • • • • • • • • • AAG17-042 8947 Buttonwood Lane NE, Olympia, WA 98516 33 Phone 9: (360)491-5155 Cell 4: (360)481-6677 N w • e rn 40V o 0 N N Y toff R id urdy Cu 109 0 N N O Jj � •�N Pr N t� W U �I 08 U 7 o a z o �0I � w C iOr p U Q O�1 � 3 O b 1 tR � b F O �• z aa rBoJoa oc2° �i Od c' ..r O. C. p D oQ ii.O U O O w O Ord cOd cd E N ti O O O c� b OA E5 Q O O 3 z '09£ �z 00 cc�d!! � py p� vi O y O G U cd p E- N y C y U ti m qq� W api b T o• h b0 X Eo w ono d o ® o 8 o o zH �wU ALL RI ' R � R : FIGURE 3. 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S-S wAmyw 6 IF 03 < nz 00 GE0a - Daol Mason County Review Checklist for a Geotechnical Report Instructions: Report. The This checklist is intended to assist Staff in Resource Ordinance.the review of a Glf an item islfound t be not appli able,l he Repiort should for completeness with respect to the explain the basis for the conclusion. are not Report is also they shoviewed ould Ibetclar flied If they do not appeay and consistency. If the r internally discussion, or recommendations consistent or consistent with the application or observations on site, this needs to be corrected or author staff shouldould refer the case to the Planning Manager or Director. d. I resolution is not achieved with the , Applicant's Name: Permit* 221 27_01° 'Q'ODZC� Parcel#: °4 Z l ZZ—I 2 CDC)2-0 Date(s)of the Document(s) reviewed: / 1. (a) A discussion of general geologic conditions in the vicinity of the proposed development, OK? ��°3 Comment: (b) A discussion,of specific soil types OK? �.:v%, Comment: (c) A discussion of ground water conditions OK? L~' _Comment: (d) A discussion,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?_ r y Comment: 2. A site plan that identifies the im.portant'development and geologic features. OK? 'Comment: 3. Locations and logs of exploratory holes or probes. OK? v'. 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? � y. 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?____y--Comment: (b) Appropriate restrictions on placement of septic drain fields OK?,_Comment: (c) Appropriate,restrictions on placement of compacted fills and footings. OK? ✓✓ Comment: Form Effective June 2008 Page 1 of 2 PP- eP°�k eokeG� G ed s by tre C�cGour<y ea M sor ara s a o the o sections �._- PssjS�enW`Nezch,�O�m a s�g�ea'pucsvas{o�the c code Senatj0nal \ CO En °nm ocnp\ete Goer y e bas e tial Inte `! P\anrnW �,c and r Masor xP\a\\\t\1 al Resod , °f tO e,\dn9 e o� Vj ay U\d e nation 1808 crr�ca\R{ot`e repot sr° to the Insor section Geote ReP° the ante . soil \ttea`N`tro ecrr\c aPP\\cab\e,ov1de cofoplexPansNe s subs the Ge rd rot s not Pr�pg,1 8 -(,7 \'\StCUGt`pt`\\st tr\usto ptePa��a ec�is{ou is report d Sectio s apes �h`s ssova\lS na ce_ \{docUmedia I to ceO Or,oloadlacentt0 Patce\# eve\oPme�t, pResovcUnlr,eO s oundat;olnn for Foundations � . �� ' 4 � {the P�oP°sea a Note•3.1 1 for f Sectio 1 sty ° Bedin9 Code `� �l the a�t�o s 0 o \c car PPp\\cap 'c.: eca\9eo\ g � Site ess scus {gets` \tyP dal P a\ -or Pag ear{\c s°\ \,o°ate ss\o o{sP cord�t�ors, Qbl�cPl\l adP\s c P\doP\s dc sPav`as sgpcev lsa�gs el du{`PlNsle� °c\Pah�o\ogytNt'a e v e\op R, ertaet\at`d sv,a�\ab\e e a �rcr us\Or geo aN �e{ere�c dscr9s\ape oa\esa 0 re locaeo `°�o{ h .Natet as vs s o uP Or ��,k�\e � y ° pe\Ocat\ {eaues ta � °\og`c s\o�o ae ac e gall a�ai dg del aoratoy° r\s oaess\o o age�sl e l{l P ocatea°�h\der`t\{ies th i o\e oc Ptobe� Z the rats\e at`a P gate P\a� MaP�sl eXP\°`atocy h' i ov aac�e�°aP°{tre l21 \ocated o�ara\ogs°{ inert,try a ge°\og`c �,�4\c \,Or, dor MaP�sl°pose-daN a a toe`° i try% ateM tic l \'°re aye ea ed l oP both s t a SC, arges -e\br Ma?� s sect\Oro ed g� z I,� et{o�med \ovate-Qr o{ore eat s o{Prof -? ara\ysesa a\ys\s ary 20 18 mV .es the- I e stap�\sty Ces Che e�m\t� 51 P co<P°�a aPlsl o{s\oP se{a\\v .\s�5,th l \orate-°r M and resin�e`N°�SaEe y{ eoo{0 escc�pti�o°u\-exa stat`c e a va l6) Paa\\es free e is sr°v\a b i '13emert o{-�ama� G\�a\YEAS co ag sl rs or P\a a -or P el stc\ct`O lal tPPPc°pC\ate�e 111 s � � Located on page(s �'t (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) I `-i t I <'�"`IC Z (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) I q- 1 5 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) ! 5, r-t(rL`t 2- (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) � 5' (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) (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) � 3 (10) An analysis of both on-site and off-site impacts of the proposed development. i Located on page(s) f o (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) { �' (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) 112 (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) 2. I, L;27i.S D t L ,° 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 ' ate of Washington with special knowledge of the local conditions. I also certify that the 4 Geotechnical Report, dated „ ?> f y and entitled r 3 meets all the requirements of the Mason County Resource Ordinance, Geologically Hazardous Areas Section, is complete and true, that the 2439- assessment demonstrates conclusively that the risks posed by the 1? landslide hazard can be mitigated through the included geotechnical CiUffi3 Dean CUShMafl design recommendations, and that all hazards are mitigated in such a (Signature and Stamp) manner as to prevent harm to property and public health and safety. Page 2 of 2 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. • �j2�2v,� .0006 (o 07 GEOTECHNICAL REPORT JASON ZACH RESIDENCE SHELTON, WASHINGTON PREPARED FOR JASON ZACH BY ALL AMERICAN GEOTECHNICAL OLYMPIA, WASHINGTON JuNE 21 2018 RN E 4 ALL GEOTECHNICAL 1 CONTACT INFORMATION PREPARER INFORMATION AAG PROJECT NUMBER: AAG18-033 CONTACT: CURTIS D.CUSHMAN I ADDRESS: 8947 BUTTONWOOD LANE NE !► OLYMPIA,WASHINGTON 98516 3 491-5155 TELEPHONE: ( 60) CELL: (360)481-6677 EMAIL ADDRESS: CURTIS.CUSHMAN@COMCAST.NET CLIENT INFORMATION CLIENT: JASON ZACK BILLING ADDRESS: JASON ZACK P.O.Box 2240. SHELTON,WASHINGTON 98584-5052 SITE ADDRESS: E.EAGLE POINT DRIVE SHELTON,WASHINGTON PARCEL: 42122-12-00020 � GPS LOCATION: N470 17'56.84" W 1231 10' 23.93" (near residence site) TELEPHONE: (360)490-6711 EMAIL ADDRESS: JASONZACK@COMCAST.NET 1 ' WA 98516 2 AAG18-033 8947 Buttonwood Lane NE, Olympia, Phone#: (360)491-5155 Cell#: (360)481-6677 IANIC ALL ,' t Lei SCOPE OF UNDERSTANDING JASON ZACK P.O.BOX 2240 SHELTON,WA SHINGTON 98584-5052 RE: GEOTECHNICAL REPORT E EAGLE POINT DRIVE SHELTON,WASHINGTON N470 17' 56.84" W 123010'23.93" PARCEL42122-12-00020 JUNE 21,2018 Dear Mr. Zack: n Zack, site property hereafter "client," hired All American Geotechnical, Inc. (AAG) in April Jason y own Jaso to prepare a geot own al report for a proposed single-family residence off E Eagle Point Drive north of Shelton, 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 is undeveloped at this time with the exception of a rough entry road. 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 twct copies for client review and distribution. Some information for this site is taken from a geotechnical investigation that was prepared by Geotechnical Testing Laboratory of Olympia, Washington titled Subsurface Soils Investigation for Marley Young (GTL) signed by Curtis D Cushman L.E.G., L.G., and dated July 3, 2008 (signed and stamped July 7, 2008). 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 furthor assistance please call us at the phone number listed below. Respectfully Submitted, ALL AMERICAN GEOTECHNICAL,INC. 1 E�r'"p G�oloq�q z;3 Curtis D. Cushman, L.G., L.E.G. Senior Engineering Geologist r 3 AAG18-(} Buttonwood Lane NE,Olympia,WA 98516 Phone#: (360)491-5155 Cell#: (360)481-6677 • ALL AMERWAN OO RW AL r 1 TABLE OF CONTENTS 6 INTRODUCTION 7 1) SITE CONDITIONS 7 SURFACE CONDITIONS 8 A) SITE GEOLOGY 9 B) SOIL TYPES 10 } C) GROUND WATER CONDITIONS 10 D) UPSLOPE GEOMORPHOLOGY 10 f E) UPSLOPE WATERBODIES AND WETLANDS 10 F) LANDSLIDE ACTIVITY 11 2) SITE PLAN 11 3) EXPLORATORY HOLES OR PROBES 11 4) PROPOSED DEVELOPMENT 11 5) CROSS SECTION 11 r 6) SLOPE STABILTY ANALYSIS 13 r GEOSEISMIC SETTING 14 7) RESTRICTIONS r 14 A) PLACEMENT OF DRAINAGE FEATURES 14 r B) PLACEMENT OF SEPTIC DRAIN FIELDS 14 r C) PLACEMENT OF COMPACTED FILLS AND FOOTINGS 14 RECOMMENDATIONS FOR SITE PREPARATION 14 r RECOMMENDATIONS FOR STRUCTURAL FILL 15 RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL 15 r D) BUFFERS 15 E) SETBACKS 15 8) CLEARING AND GRADING PLAN � 15 9) EROSION CONTROL PLAN 16 10) ON AND OFFSITE IMPACTS 16 11) FINAL DEVELOPMENT CONDITIONS 16 12) STRUCTURAL MITIGATION 16 13) SITE PLAN 16 f CONCLUSIONS AND RECOMMENDATIONS 17 PROVISIONS 17 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 17 READ THESE PROVISIONS CLOSELY 18 REFERENCES WA 98516 4 AAG18-033 8947 Buttonwood Lane NE,Olympia m#a'60 481-6677 Phone#: (360)491-5155 ( ) . ALL AMERIC AN ,O '' I 20 APPENDIX 2009 AASHTO DESIGN SPECIFICATIONS 21 2015 IBC DESIGN SPECIFICATIONS 22 SLOPE MODELS 23 ' STATIC MODEL A-A'LINE 23 DYNAMIC MODEL A-A'LINE 24 FIGURES 25 b FIGURE 1.VICINITY MAP 25 FIGURE 2.SITE PLAN 26 FIGURE 3. EROSION CONTROL NOTES 27 1 I i i AAG18-033 8947 Buttonwood Lane NE, Olympia,WA 98516 5 Phone#: (360)491-5155 Cell#: (360)481-6677 r AMripIC,AN. GtoTEC 1 1 i INTRODUCTION This report summarizes the results of our geotechnical consulting services for the residential site herein described. The proposed residence is located on the south side of E Eagle Point Drive approximately 1.7 miles from State Route 10 on the Jason Zach property just east of 991 E Eagle Point Drive. The site is approximately 5 direct miles north-northwest of downtown Shelton, Washington. The location of the site is shown relative to the surrounding area on the Vicinity Map, Figure 1. The parcel in a large rectangle long to the north-south. The site is cut roughly in half by E Eagle Point Road which crosses it from the west to east. The larger part of the parcel north of the road is marked by a steep slope down to E Purdy Cutoff Road. The residential building site and other potential sites are south of E Eagle Point Road. Our understanding of the project is based on our discussions with the client, Mr. Jason Zack; and references to the report of 2008 for Marley Young by Geotechnical Testing Laboratory. In general, this will be a project involving developing part of the parcel for the construction of a single-family dwelling and some outbuildings. The approximate layout of the site is shown on the Site Plan, Figure 2. The purpose of our services is to evaluate the surface and subsurface conditions at the site in order to satisfy the requirements of the Mason County Critical Areas Ordinance, and as a basis for providing geotechnical recommendations and design criteria for the project. All American Geotechnical is therefore providing geotechnical services for the project. Specifically, our scope of services for this. project includes the following as needed: II 1. A review of the available geologic, hydrogeological and geotechnical data foK the site area. 2. A geologic reconnaissance of the site area and surrounding vicinity. 3. Investigation and identification of shallow subsurface conditions at the site by characterizing the exposed soil,reviewing published well logs, and sampling. 4. Comparison of site to published geologic maps, previous field investigations, and open file reports. Inspection of aerial photography is 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. 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 north side of the site. This is a road cut with a lesser slope above it 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. AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 6 Phone#: (360)491-5155 Cell#: (360)481-6677 i ALL ANIEpIC,AN GKOnCHNIC 1) SITE CONDITIONS ' SURFACE CONDITIONS ' The site is on the ridge south of the recent road cut that was done to improve E Eagle Point Drive. The 1 site has a platform at its northern side suitable for a single-family dwelling. On a somewhat lower platform to the south, there is adequate room for outlying buildings. The potential building sites have been logged and cleared of vegetation and they are linked by new roads to be used for development. Much of the residential building site is exposed soil/glacial material 1 " The site was visited by Curtis Cushman L.E.G. and Blaise Jelinek E.I.T. on May 7, 2018. The client was on site. The purpose of a site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. A site map was prepared identifying features of the property. Surficial exploration and inspection of outcrops was done. The GTL report contains the results of the boring tests done at the time with their laboratory analyses at the lower level of the road. 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 although there is a sloughing feature that will be detailed, below. No surficial water is present. No active .: erosion was seen. The slope and road cut to the north are in very hard l kames de glacial deposits. p m The LiDAR map to the right is a r � " w bare earth depiction of the property. The semi-circular feature to the east ' is mapped as mass wasting but does not appear to affect the area of � f immediate concern. F J The property where it is not cleared is vegetated with mature and , X r juvenile trees, notably evergreens, and various varieties of native plants. Trees are predominately straight and vertical. The road cut is defined as a landslide hazard area(LHA). The top of the cut will be the limit of the LHA. A vegetation buffer will extend 50 feet up the lesser slope and onto the building platform. However, the residential area is cleared and the lower parts of the property are well behind the 50-ft slope buffer. AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 7 Phone#: (360)491-5155 Cell#: (360)481-6677 I ► ALLi ? ( GKOTEC r 1 1 A) SITE GEOLOGY 1 Puget Sound glacial province. a arhe ea slstin theg sult of he mosttopography, as ell as much of The site is situated within the recent Vashon r the sedimentary deposits and surficial subsurface soils in the , ago, an stade (stage) of the Fraser glaciation that occurred betwee f about failure,0however,and 0e0 posesspre-Fra er 1 weathering and erosion that has occurred since. The site o 1 deposits derived from the Olympics. A description of the surficial soils is included in the "Site Soils" 1 section of this report, below. In general, the deposits are composed of glacial material with the soils 1 directly derived from this material. ► The Geologic Map of the Skokomish Valley and Union 7-5-minute Quadrangle, Mason County, 1 Washington Open File Report 2010-03 by Polenz, Michael and others (revised 2011), p Y the 1 Washington Division of Geology and Earth Resources) maps the site as follows. 1 The description below is ordered with the younger deposits above the older. 1 1 Qmw 1 Mass wasting deposits—Cobbles, pebbles, sand, silt, clay, boulders, and diamicton; generally unsorted, ► but locally stratified; loose; shown along potentially or demonstrably unstable slopes. 1 These unusual deposits, many linear or arcuate in nature,aare is theicommonly, Dos e nature.not They doalways, not appear to be 1 steep slopes. Their main characteristic of note in this are 1 landslide deposits on the mapping scale, but instead are sloughs of material on steep slopes, mostly 1 - Holocene in age 1 If present at all, this unit would be at the western edge of the property and should not be involved with 1 the residential or other developments. 1 r Qgik 1 Vashon ice-contact kames and kame deltas—Gravel, sand, and some silt; mostly loose; medium to very r thickly bedded or massive; moderately to well stratified. 1 ! These are deposits that are most commonly mapped on the property. They are deposits of glacially scoured material that collects upon the glacial ice following e glacial elting retreat. underlain by I These deposits can be loose or well compacted in the nature of a lodgment till. Thee are ! the following: 1 1 Qpu°P I Pre-Fraser Olympic-source glacial and nonglacial deposits—Gravel, sand, silt, clay, and diamicton, 1 including tills and paleosols; tan to reddish brown or gray; compact;poorly sorted. I ! 8 I AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 Phone#: (360)491-5155 Cell#: (360)481-6677 I t ALL IC& GEoTECHNICAL These compacted sediments are common in the area and are deposits from the pre-existing river channel that is followed today by the Skokomish River. These underlie the later glacial deposits and can be well- s deposits appears irregular and ill defined, causing the compacted. The contact with the overlying kame deposits to blend in. The samples laboratory tested in the report for Marley Young were most likely Pre- Fraser deposits. The face of the road-cut has been mapped as kames deposits. While there is the possibility it is the underlying pre-Fraser, the similarity of the units has led to the similar coefficients in the slope stability models, below. The material in the road-cut in any event is very compact and hard either due to glacial loading or lodgment deposition. The undisturbed material is generally quite good for construction and will not have major problems supporting construction. B) SOIL TYPES The soil at the road is: Sh—Shelton gravelly sandy loam, 30 to 45 percent slopes Map Unit Setting National map unit symbol: 2hn3 Elevation: 100 to 800 feet Mean annual precipitation: 50 to 70 inches Mean annual air temperature:48 to 50 degrees F Frost-free period: 150 to 180 days Farmland classification: Not prime farmland Map Unit composition Shelton and similar soils: 100 percent Estimates are based on observations, descriptions, and transects of the mapu nit. Description of Shelton Setting Landform: Moraines Parent material: Basal till with volcanic ash This is a common soil for the area and is derived from specific glacial materials. It is mapped here to the ! east of the proposed development area. It is not relevant to proposed construction. It is important for 1 erosion control that I not be removed outside the project area. I Gc—Grove cobbly sandy loam, 5 to 15 percent slopes I Map Unit Setting National map unit symbol: 2hkg Elevation: 200 to 790 feet I Mean annual precipitation: 90 inches Mean annual air temperature: 48 degrees F Frost-free period: 160 to 180 days I Farmland classification: Not prime farmland i 7AG18-033 8947 Buttonwood Lane NE, Olympia,WA 98516 9 Phone#: (360)491-5155 Cell#: (360)481-6677 ' ALL AmmicAN GE 1 Map Unit composition Grove and similar soils: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Grove Setting Landform: Outwash plains Parent material: Glacial outwash Typical profile H1 - 0 to 13 inches: cobbly sandy loam H2 - 13 to 28 inches: very gravelly sandy loam H3 - 28 to 60 inches: very gravelly loamy 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 I Frequency of ponding: None Available water storage in profile: Low (about 3.0 inches) 1 This description well describes the soils seen on site. Those at the residential site have been removed to I the underlying glacial unit. I Elsewhere, the soil appears to be present. I C) GROUND WATER CONDITIONS No surface water flow was observed on site. There was no evidence of springs on the slope. i D) UPSLOPE GEOMORPHOLOGY The slope to the south flattens out to form part of a broad highland. A knoll at just over 390 feet is to the west of the road failure site, and to the southeast is a plateau at over 440 feet in elevation, approximately 2000 feet away. These pose no hazard. E) UPSLOPE WATERBODIES AND WETLANDS There are none. F) LANDSLIDE ACTIVITY The Skokomish/Union 7.5-minute quadrangle shows the area to be of limited mapable landslides, Most of these are relatively small failures in the lowermost part of the bluffs lining the south side of the Skokomish River valley. 'There is one large slide approximately due east but away from the project site, AAG18-033 8947 Buttonwood Lane NE, Olympia, WA 98516 10 Phone#: (360)491-5155 Cell#: (360)481-6677 A AM, EpICAN GEoTECUI 1 , 1 and it appears associated with a large steep drainage. The hillside and slopes qualify as a landslide � , hazard area,but the factors of safety at the site will be discussed,below. I 2) SITE PLAN ► The proposed location of acceptable residential and other building development is shown on Figure 2. The building envelope where this construction is acceptable from a geotechnical sense is marked. The I residence site is as currently planned. The building envelope is necessarily large for the southern part of ► the property as exact building locations are yet to be determined. ► 3) EXPLORATORY HOLES OR PROBES ► Sample locations were from north of the road. (See 2008 soil report.) The road cut presents a totally exposed column that extends down the entire change of elevation from the residential site down to E Eagle Point Road. Hand samples for this report were from the many exposures across the site. i 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 Two cross-sections are in the Appendix along line A—A'. 6) SLOPE STABILTY ANALYSIS As noted above,there are some mapped landslides in the area. LiDAR shows no signs of major landslides in the immediate area. There is a history of local landslides primarily along the base of the bluff along the Skokomish River. There was no evidence of significant recent erosion observed onsite at the time of our investigations. The failure of the roadside appears local and does not indicate deep failure. 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 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 steep nature of the slope north of Eagle Point Road and weakening by previous land slippage resulted in the re-establishing of the road approximately 10 feet to the south. AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 11 Phone#: (360)491-5155 Cell#: (360)481-6677 1 ' ALL AMERIC ,AN Gr toTECHNICAL Following construction, encouraging vegetation and discouraging runoff from the steep slopes can reduce I 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. 1 I 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 I analysis should include the Simplified Bishop's Method of Circles. The minimum static I safety factor is 1.5, the minimum seismic safety factor is 1.1 and the quasi-static analysis 1 coefficients should be a value of 0.15. I Factors of safety were determined using the Bishop (semi-circular) method. The site was modeled with two layers of material; our field exploration did not find the two materials to be different within our area of investigation. The parameters used in this modeling were based on experience with the surroundings and the types of materials encountered on site, and laboratory result from the GTL 2008 report. A ground water table was not included in the mode of 1500 lb erl based on our te investigation.fo t was placed across the intercept oic road f was not applied to the model. A continuous loadp 1 the proposed residence and the cross-section. 1 1 Slope stability was modeled using the GALENA 6.1 program in both static and dynamic conditions (Ca= 0.208). "Static" condition refers to an "as is" state of a given slope. "Dynamic" puts seismic 1 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 1 Appendix. 1 The soil was laboratory classified in the range of SW-SC Well-graded sand with clay. The sample was 1 collected at about 8-feet below ground surface from boring H-2. This classification required a model that 1 _ mixes the material, selecting conservative values in the interests of safety. 1 The site was modeled as two similar units. The material in the current road cut best fits the description of 1 the Pre-Fraser Olympic-source glacial and nonglacial deposits (Qpuop), as seen at the road cut. Above the proposed road cut is the Vashon ice-contact kames and kame deltas (Qgik); this unit is included as a 1 cap on the model. The geologic units at the lower end are not relevant to the analysis and are not included on the cross-sections. The units were modeled using the following soil parameters presented in 1 Table 1. Geologic Unit Modeled Values. ! Table 1. Geologic Modeling Values Geologic Unit .Unit Weight- Cohesion phi angle 120 225 30 puo! ------- ----•--------------- ------ -�- I ik 124 400 32 1 Two analysis were calculated along the A-A' line, itemized on Table 2. Modeling Parameters and 1 Findings. The Analysis Number corresponds to the output presented on pages 23-24. The slope was modeled based upon observations and field measurements Initial positions were selected based upon the I placement of the structure. The initial points were varied over the analysis range indicated; with 50 1 AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 12 Phone#: (360)491-5155 Cell#: (360)481-6677 NOR Oil Saw I ALL NI Gr AL - 1 I 1 `different positions tested across these ranges. A total of 125,001 calculations were performed for each I analysis. I Table 2.Modeling Parameters and Findings 1 EConfiguration ; FactoAnalysis ; Analysis Initial Positions (Analysis Range)_Number ; Type Lower Upper Radiusalculated Safe 125,001 1.96] 1 - 1 Static - 173 (70)- 340 (48) -- 210 (20) --- - - - - - 1 2 ; Dynamic ; 173 70 340 48 210 20 125,001 1.2 1 1 Under static conditions, the slopes generally did not show susceptibility to shallow failure that would cause damage to the proposed residence. Under dynamic loading (Ca=0.208), the computations I demonstrated that the upslope is safe and not susceptible to a deep-seated movement. I I These calculated Factors of Safety (FOS) meet the requirements set forth by Mason County for static I ent (1.10) for dynamic loading scenarios on the lower slope conditions (1.50) and meet the requirem analysis. Calculated Factors of Safety are presented in Table 2. GThe site appears stable based on our 1 slope models representing critical slopes at the subject site Lesser Factors of Safety values are found ! when the model is extended well down the erosion valley to the north. This is most likely an artifact of i the profile, as cross-section line A — A' threads a needle in entering the steep drainage channel at the line's northern end. The overall site geometry indicates stability albeit with the cautionary note that this I steep area does have some history of local failure on a large scale. I The values inputted were selected to be as conservative as possible so the FOS are likely higher. I Magsino, Poelstra, The Liquefaction Susceptibility Map of Mason County, Washington by Palmer, I Bilderback, Folger, and Niggemann (September 2004) maps the site area as having a Very Low to Low liquefaction potential The Site Class Map of Mason County, Washington by Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004) maps the site area as site Class C to D. Site class C is a very stiff soil or ! soft rock and Class D is stiff soil. ! GEOSEISMIC SETTING 1 I o the Seismic Zone Map of the United States contained in the 2006 International Building According t ! Code (IBC) the project site is located where the maximum spectral response acceleration is 40 percent of I gravity (g). We recommend following seismic factors for design purposes. D (Stiff Soil) • Site Class: 1.445g(Fa= 1.05) Spectral response acceleration, short periopd (SM( 0.900 F,�= 1.55) Spectral response acceleration, 1-second eriod SMi): g Peak Ground Acceleration(PGA) 0.415g I 8947 Buttonwood Lane NE,Olympia,WA 98516 13 AAG18-033 Phone#: (360)491-5155 Cell#: (360)481-6677 1 I r ALL AMERICAN GEOTEC 1 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, to either the north or west. A capture system could be done with the water preferably tightlined to the south. No surface water and no storm discharge of any sort should be directed toward the bluff. 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 any existing structures, debris, duff, and vegetation. All deleterious material will be removed at the time of the earth-moving to grade the new part of the road. 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. 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 Il 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 j 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. AAG18-033 8947 Buttonwood Lane NE, Olympia, WA 98516 14 Phone#: (360)491-5155 Cell#: (360)481-6677 f 1 I RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL I i 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. No compacting or fill is foreseen. The following notes are for completeness in case some fill is required: The site material appears from the 2008 GTL lab reports to be suitable for structural fill. Such use would require compaction testing. D) BUFFERS The residential site as currently planned is outside the 50 foot vegetation buffer. If the final plan intrudes upon the buffer area, a waiver should be granted as the vegetation had been removed to prepare access to the site and the site itself. There is no lower end of the LHA marked on Figure 2 as it is not relevant to this project. E) SETBACKS \� It is recommended the geotechnical setback correspond with the 50' vegetation buffer as the modelling indicates this has acceptable Factors of Safety. 8) CLEARING AND GRADING PLAN The primary cutting and grading of the site have been done.("No Disturb" zones will not be re_ q`uire_d. Further work will be to develop the footings of the structures and improve the roads. No major grading shall occur. All job site safety issues and precautions are the responsibility of the contractor providing services and/or work. 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 has been done at the time of timbering and clearing of the residential building site. Revegetation as needed should occur immediately following construction. Any hazard trees may be removed with the roots left in place if possible. The possibility of down-slope contamination is highly unlikely if proper control methods are employed. A silt fence and some other control methods, such as swales, are possible. Work should be one under dry conditions and the downhill slope at least protected by loose hay or bales of hay. AAG18-033 8947 Buttonwood Lane NE, Olympia,WA 98516 15 Phone#: (360)491.-5155 Cell#: (360)481-6677 min ALLAtcAN GcOTECUINIC AL Straw, hay, or jute matting shall be used to cover exposed soils until permanent vegetation is established. The road cut itself should be protected against the rains and revegetation should be apart of the overall project. All other denuded 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 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 1 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. 1 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 There is none. 13) SITE PLAN Please see Figure 2. 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 e iminate the potential for erosion in this area. AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 16 Phone#: (360)491-5155 Cell#: (360)481-6677 1 1 Work may be performed under most weather conditions. We recommend that earthwork be undertaken during favorable weather conditions. 1 Revegetation should be done as per recommendations in the text, above. 1 1 PROVISIONS prepared this report for the exclusive use of Jason Zack and his authorized agents for the We have p re p County, Washington. Site inspections, research, and proposed residence on Eagle Point Drive in Mason 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, 1 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 n steep slopes. The property owners should monitor the stability failure and landslides can and do occur o of the road following construction. 1 1 Moreover, acceptable Factors of Safety do not guarantee there cannot be failures. It is the responsibility derstand that there are always risks in building on or near steeply of the property owners association to un sloped areas. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 1 Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, f the work site. The contractor is solely responsible for job site safety and for schedule or management o 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 capectations includes t at could lead explanatory ! disappointments, claims and disputes. All American Geotechn ► "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 i regarding a specific project. i i AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 17 Phone#: (360)491-5155 Cell#: (360)481-6677 i ALL 1 G oTrACK4 REFERENCES MAPS DeLorme 3-D TopoQuads(2002),Source Data USGS,Yarmouth,Maine. Dragovich, Logan, Walsh,and Schasse(2002), Geological Map of Washington—Northwest Quadrant(Geological Map GM- 50),published by Washington State Department of Natural Resources. Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann (September 2004), The Liquefaction Susceptibility Map of Mason County, Washington,published by Washington State Department of Natural Resources. 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.(2012),Geologic Map of the Skokomish Valley and Union 7.5-minute Quadrangle, Mason County, Washington;Washington State Department of Natural Resources DNR OF 2010-03 (Revised 2011) Rogers, A. M., Walsh, T. J., Kockelman, W. J., and Priest, G. R. (1996), Map showing known or suspected faults with quaternary displacement in the Pacific Northwest, published by U.S. Geological Survey OFR 91-441-0, Plate 1, scale 1:2,000,000. Smith, Carson (1977), Relative Slope Stability of the Southern Hood Canal Area, Washington, prepared in cooperation with the Washington Department of Natural Resources Division of Geology and Earth Resources; and,Department of the Interior United States Geological Survey. PUBLICATIONS ASTM International(2005),Annual Book of Standards 2005, Section 4, Volume 4.08,published by ASTM International, West Conshohocken,Pennsylvania. International Code Council,Inc.(2006),2006 International Building Code,published by International Code Council,Inc. Kollmorgen Instruments Corporation (1994), Munsell Soil Color Charts (1994 Revised Edition), published by Macbeth Division of Kollmorgen Instruments Corporation,New Windsor,New York. Ness,Fowler,Parvin(1960),The Soil.Survey of Mason County, Washington, USDA Soil Conservation Service, in cooperation with the United States Department of Agriculture, and Washington Agricultural Experimental Station, and the Soils Conservation Service. Parks, Neal, Koloski, Laprade, Molinari, Butler, and Lorentson (November 2006), Guidelines for Preparing Engineering Geology Reports in Washington, published by Washington State Geologist Licensing Board,Olympia,Washington. 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. 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) AAG18-033 8947 Buttonwood Lane NE, Olympia,WA 98516 18 Phone#: (360)491-5155 Cell#: (360)481-6677 ' ALL ANERIC GE OTEC H Puget Sound Lidar Consortium (http://pugetsoundlidar.ess.washington.edu/lidardata/index.html) r 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.govibiblio/9331.html) United States Department of Agriculture Natural Resource Conservation Service (http://soildatamart.nres.usda.gov) Washington Administrative Code (http://apps.leg.wa.gov/waci) Washington Department of Ecology (http://apps.ecy.wa.gov/welllog) (https:Hfortress.wa.gov/ecy/coastalatlas/viewer.htm) AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 19 Phone#: (360)491-5155 Cell#: (360)481-6677 r 1 ALA, ANERIC AIN GEOTIRCHNIC-AL 1 I 1 APPENDIX I 1 1 ► USGS Seismic Design Specifications 1 Slope Models I I Figure 1.Vicinity Map ► Figure 2. Site Plan I Figure 3. Erosion Control Notes I I I I I I I I - AAG18-033 8947 Buttonwood Lane NE, Olympia,WA 98516 20 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AMERICAN GEOTEC-HCA ' 2009 AASHTO DESIGN SPECIFICATIONS Design Maps Summary Report User-Specified Input Report Title Jason Zack Tue June 19,2018 21:42:11 UTC Building Code Reference Document 2009 AASHTO Guide Specifications for LRFD Seismic Bridge Design (which utilizes USES hazard data available in 2002) Site Coordinates 47.2990N, 123.17°W Site Soil Classification Site Class D -"Stiff Soil" Risk Category I/II/III ., K . z USGS-Provided Output PGA = 0.415 g AS = 0.450 g Design Response Spectrum Ss = 0.919g Sos = 1.041g 1.1) S1 = 0.361 g SDI = 0.606 g 0754 GkSi r^� 5 cry t,:ss 0A4 033 022 G.I1 0AY Olt. 0-3) CIA- ut« (IN-1 1- 1,3) 1*1 1W 1ki"i _,x, Peri(A,T ism) 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. i I AAG18-033 8947 Buttonwood Lane NE, Olympia, WA 98516 21 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AN GEOTrACHNICAL 1 1 2015 IBC DESIGN SPECIFICATIONS 1BUM Design Maps Summary Report 1 User-Specified Input 1 Report Title Jason Zack Tue]une 19,2018 21:39:56 UTC 1 Building Code Reference Document 20 c2/u 0 es International USGS hazard data B 20uilding e (wh ' Site Coordinates 47.29911N, 123.170W 1 Site Soil Classification Site Class D -"Stiff Soil" 1 Risk Category I/II/III 1 o-, 1 1 1 �5helton itt Al2r, 1 USGS-Provided Output 1 Ss = 1.445 g Sns= 1.445 g SDs = 0.963 g 1 S., = 0,600 9 SMi = 0.900 g SDI = 0.600 g 1 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 i'2009 NEHRP"building code reference document. ' Design Response Spectrum NICE,Response Spectrum Lw IAs t i� 1 Lw O:>o was n»> t s u.T. 1[t5 '3 uto on u5� ' n?5 @t13 Olt? ' Ud5 ua� Paul 0.10 1 O,IS ❑31l 9AA} t),al O.Y:) Gtfi uH7 IlJa I.ID I.Y3 Ihn I3Yt 2fX1 1 oix, o.a @ u, um o»r I/1, I.a; I u, ttl t I zta Period.T(sec) Pleritid.T isce) Although this information is a product of the U.S.Geological Survey,we provide no warranty,expressed or implied,as to the accuracy of 1 the data contained therein.This tool is not a substitute for technical subject-matter knowledge. I � 1 AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 22 Phone#: (360)491-5155 Cell#: (360)481-6677 1 I 1 ALL AMERICANGMTECHNICAL SLOPE MODELS ` STATIC MODEL A-A'LINE cit s_ c a� c ? 81 H m y n cc mi -o o Q� 1 � o M �i O O < M u7 N O N O R 0 0 6 'n u W � � 0 0 0 0 0 o t� V C�7 M N '� V! m U Q k AAG18-033 8947 Buttonwood Lane NE,Olympia,WA 98516 23 Phone#: (360)491-5155 Cell#: (360)481-6677 ALL AIM RICAN HNICAL ' DYNAMIC MODEL A-A'LINE ' � U N � C cz en c c° a ua to c o 4 n T atE�l in ca U U Ej }o cQ m h 4a e �.0 Q QC U w Q Q 0 V tt� m c M 0 04 N O N g 4 0 0 N W U W c tto 0 0 0 0 0Q -- oo c,jto a "' V' V' CM I AAG 18-033 8947 Buttonwood Lane NE, Olympia,WA 98516 24 Phone#: (360)491-5155 Cell#: (360)481-6677 i. i ALL A.mv.,fti A EO H I'C L I i FIGURES i FIGURE 1.VICINITY MAP I 123°12'00"W 123°11'00"W 123°10'00"W WGS84 123°09'00"W 1 .fat —��►�. �_! — — Z 47 r Y� - ' jo BN3 7 fST!' s t L !4 k, is 1-134QD '.y-•. S N v A �K� � �G 4 � T QI - n 'rY Sid a J r Parc2 " w i " - ,n� ` fi t k,Bcrien �. BU273.6 4kt 248 '•r f 7 j \ f •� �``. " r moo. n r 123°12'00"W 123°U11'00"W " 123110'00"W WG584 123°09'00"W 5 1 M#E rn a o00�E{r o saa o0o&AWAS 16`` ?noted from TOM 02001 A#ti-aJ Ge Fsphic Holdio[n 0111".t0po.M) AAG 18-033 8947 Buttonwood Lane NE, Olympia, WA 98516 25 Phone#: (360)491-5155 Cell#: (360)481-6677 ALA > A-MIERICAN E HNW FIGURE 2.SITE PLAN AAG18-033 8947 Buttonwood Lane NE,Olympia, WA 98516 26 Phone#: (360)491-5155 Cell#: (360)481-6677 • I I I ' i / 1 A A A v ---------------- ---------------------- 1 ----------- - \ ---- 11 \\ \ \ \ $ Q \ Q \ 1 \ \ V \ \ \ 1 \ \ \ \ \ \ \ \ \ I I I I I I \ 1 \ O \ \ \ 1 \ \ \ \ \ \ \ \ \ \ \ 1 I I I I I I \ I 1 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 1 I I I I 1 I 1 1 I \ 1 1 \ \ \ V \ \ \\ \ \ \ \ \ \ \ 1 I I I I V 1 1 I \ \ 1 \ \ \ \ \ 1 I 1 1 \ 1 1 I I 1 I 1 1 1 \ 1 \ \ \ \ \ \ \ \ \ \ 1 I 1 I 1 1 1 1 1 I I \ I I I \ 1 \ l I \ V \ \ 1 \ 1 1 I I I I 1 1 I I I I 1 1 I I I I N I 1 111 11 I N I 111 1\\ II II M I ` 1 \ I 1 1 \ \ \ \ I 1 I I \ \\ \ \ I \ I \ \\ I I 1 \ \ I I I 11 Site Geology 1 ! I I Qpuop--Pre-Fraser Olympic-source glacial and nonglacial deposits I I Qgik--Vashon ice contact kames and kame deltas Qmw--Quaternary mass wasting deposits Qaf--Artificial fill All American Geotechnical,Inc. Project Drawn By: Site Plan Permi 8947 Buttonwood Lane NE Number: BWJ Proposed Residence Olympia,Washington 98516 AAG18-033 6/14/18 Shelton,WA Appli Revisions: \ NOTES This is not a survey. This map is a presentation of information from county, -- state, and federal sources,client provided information, and onsite observations; for discussion purposes of the report with which this map is included. Geologic contacts are approximate. - -- --- ................. o a Q Say 1 I a I SCALE 1'=80' \,\ C.I.=5' \ / \ 0 20 40 60 BO l 'Lc J�� \ 1 / Site Soil 39 �y Se g Shelton gravelly sandy loam, 30 to 45 percent slopes. CU S DeandiAlnj 1 / i I Number: Parcel Numbers: 42122-12-00020 Figure Jason Zack IOXX East Eagle Point Drive 2 ant Name: Site Address: ALL icA GEOTECHNIC FIGURE 3. EROSION CONTROL NOTES 1 1 I 1 I I I I AAG18-033 8947 Buttonwood Lane NE, Olympia, WA 98516 27 i Phone#: (360)491-5155 Cell#: (360)481-6677 i 1. 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'-0" 1. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIOR TO THE BEGINNING OF CONSTRUCTION. THE PROJECT ENGINEER AND TF 5'-0" //-A\ UND SURFACE SHALL INSPECT AND APPROVE THE INSTALLATION OF EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUG 2'-6" :.:...........................:.:... 2. EROSION CONTROL MEASURES ARE NOT LIMITED TO THE ITEMS : 6'MAX ON THIS PLAN. THE CONTRACTOR IS RESPONSIBLE FOR THE INSTALLATION AND MAINTAINANCE OF ALL EROSION CONTROL ME. NO SILTATION OF EXISTING OR PROPOSED DRAINAGE FACILITIES SHALL BE ALLOWED. CARE SHALL BE TAKEN TO PREVENT MIGRAT 2"X4"WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER OF SILTS TO OFF SITE PROPERTIES. BETTER OR EQUAL ALTERNATE: MATERIAL IN 8"X12"TRENCH STEEL FENCE POSTS 3. THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL ERO. CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR AD TO THE EROSION CONTROL MEASURES. THE CONTRACTOR SHALL 1 ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECE I BY THE COUNTY INSPECTOR AND/OR THE PROJECT ENGINEER. FA FILTER FABRIC- 6" TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL REQUIREMENTS MAY RESULT IN CIVIL PENALTIES BEING LEVIED 2"X2"X14 GAUGE WIRE FABRIC OR EQUIVALENT AGAINST THE CONTRACTOR AND/OR PROJECT OWNER. ' 2'-0" GROUND SURFACE 5'-0" 4. DURING THE WET SEASON(NOVEMBER TO MARCH)ALL DISTURBEE SHALL BE STABILIZED WITHIN 48 HOURS AFTER STOP OF WORK. EE PROVIDE 3/4"-1 1/2"WASHED CONTROL MEASURES SHALL INCLUDE,BUT NOT BE LIMITED TO, ' GRAVEL BACKFILL IN TRENCH 12" COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WITH AND ON BOTH SIDES OF FILTER PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULC ` FENCE FABRIC ON THE SURFACE 8"'MIN OR WOOD CHIPS. SEEDING OF THE DISTURBED AREAS SHALL TAKE PLACE AS WEATHER PERMITS. 2"X4"WOOD POSTS 5. ALL SEEDED OR SODDED AREAS SHALL BE CHECKED,REGULARLY ALT:STEEL FENCE POSTS TO MAKE SURE VEGETATIVE COVERAGE IS COMLETE. AREAS SHAL 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 THE LENGTH OF THE BARRIER TO AVOID USE OF JOINTS. WHEN JOINTS TRACKED ONTO A COUNTY STREET,IT SHALL BE REMOVED BY THE I ARE NECESSARY,FILTER CLOTH SHALL BE SPLICED TOGETHER ONLY AT OF THAT WORKING DAY. ANY FURTHER TRACKING OF MUD WILL TH A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY BE PREVENTED BY SWEEPING OR WASHING OF THE VEHICLES TIRE 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 THI ! 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 T INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER. 4. WHEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH 9. TRENCH DEWATERING DEVICES SHALL BE DISCHARGED IN A MANNE SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE NOT ADVERSELY AFFECT FLOWING STREAMS. DRAINAGE SYSTEMS OF THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST 1 INCH OFFSITE PROPERTIES. LONG,TIE WIRES OR HOG RINGS. THE WIRE SHALL EXTEND INTO THE TRENCH A MINIMUM OF 4 INCHES AND SHALL NOT EXTEND MORE THAN 36 10.ALL STORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJEC INCHES ABOVE THE ORIGINAL GROUND SURFACE. CONSTRUCTION SHALL BE PROTECTED SO THAT SEDIMENT-LADEN WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM. 5. THE STANDARD STRENGTH FILTER FABRIC SHALL BE STAPLED OR WIRED TO THE FENCE AND 20 INCHES OF FABRIC SHALL BE EXTENDED 11.ALL OFF-SITE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE INTO THE TRENCH. THE FABRIC SHALL NOT EXTEND MORE THAN 36 SHALL BE PROTECTED FROM SILTATION. INCHES ABOVE THE ORIGINAL GROUND SURFACE. FILTER FABRIC SHALL NOT BE STAPLED TO THE EXISTING TREES. 12.ALL DISTURBED AREAS SHALL BE SEEDED OR SODDED UPON COMP 6. WHEN EXTRA-STRENGTH FILTER FABRIC AND CLOSER POST SPACING IS OF WORK, THE CONTRACTOR SHALL BE RESPONSIBLE TO ENSURE USED,THE WIRE MESH SUPPORT FENCE MAP BE ELIMINATED,IN SUCH COMPLETE COVERAGE OF THE DISTURBED AREAS IS PROVIDED&T A CASE,THE FILTER FABRIC IS STAPLED OR WIRED DIRECTLY TO THE GROWTH OF THE VEGETATION IS ESTABLISHED. 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 I 8947 Buttonwood Lane NE BWJ 6/14/18 Proposed Residence Olympia, Washington 98516 Shelton,Washington E Revisions: r n a• . �i��00i�riJ/\�2/i0/i r\i; r /....� _ 1i•��io,�0�' C• 1 . • •• . •