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GEO2009-00069 for BLD2009-00704 - BLD Engineering / Geo-tech Reports - 9/25/2009
MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Planning Division P O Box 279, Shelton, WA 98584 1[914 (360)427-9670 Geotechnical ReportReview Acceptance Letter September 25, 2009 KOEHL/BREEDEN 10505 118TH PL NE KI RKLAN D WA 98033 Case No.: GE02009-00069 Parcel No.: 322345000014 Proiect Description: GEO TECH REPORT SUBMITTED FOR BLD2009-00704 The Geotechnical Report for KOEHL/BREEDEN has been received and reviewed by the Planning Department. The report was prepared by Curtis Cushman dated 7/14/2009. Based on the certification provided by the licensed engineer/geologist, the referenced Geotechnical Report was prepared in general accordance with the requirements in the Mason County Resource Ordinance, Landslide Hazard Areas 17.01.100.E.5. Mason County considers the review valid until such time as scope of project, site conditions, and/or regulations change. Should the scope of work, site conditions, and/or regulations change after the original review, then an addendum from the original author of the report may be required to address these changes. The report would only be re-reviewed if a permit for development were submitted after these changes occur. Mason County does not certify the quality of the work done in this Geotechnical Report. Please contact me at (360) 427-9670, ext. 365 if you have questions. Sincerely, TO LAC y`��"T cr . Allan Borden r 7IA r�l�s f� Land Use Planner ' y k ' Mason County Planning Department Comments: I 9/25/2009 Page 1 of 1 GE02009-00069 Mason County Review Checklist,'& For a Geotechnical Report ] f� Instructions: This checklist is intended to assist Staff in the review of a Geotechnical Report. The GeotechnicM*R,'pglt. 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: 62"`I _32Z2)f � 000t� Permit# Parcel# Date(s)of the Document(s) reviewed: -i'2"""� (1) (a)A disci4gsion of general geologic conditions in the vicinity of the proposed development, OK? V Comment: (b) A disc sion of specific soil types OK? Comment: (c) A discu4ssion of ground water conditions OK? ✓ 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 activity in the vicinity, as available in the OK?refere ed maps and records Comment: (2) A site plan hich identifiesAatoif"y mportant development and geologic features. OK? Comment: (3) Locations d logs of explholes or probes. OK?Comment: (4) The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks�Kall be delineated p, both sides, and toe)on a geologic map of the site. OK? V Comment: G . (5) A minimum of one cross s tion t a scale which adequately depicts the subsurface profile, and which incorpprates the details o ropose grade changes. OK?_�Comment: (6) A description and results of s pe s ability analyses performed for both static and seismic loading conditions.Analysis should examine worst case failures. The analysis should include the Simplified Bis op's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic s y factor is 1.1. and the quasi-static analysis coeffients should be a value of 0.15. OK? Comment: (7) (a)Approp 'ate restrictions on placement of drainage features OK? Comment: (b) Appro late restrictions on placement of septic drain fields OK? V Comment: (c) Approp08te restrictions on placement of compacted fills and footings OK? Comment: (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Page 1 of 2 Form Effective June 2008 OK/Comment: AfKi� Y (e) Recommended setbacKi froill the landslide hazard areas shoreline bluffs and the tops of other opes on the property. - OK? Comment: (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method o egetation removal. OK? Comment: �`Z Z (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 fro rosion, landslides and harmful construction methods. OK?Comment: (10) An analys}'aof both on-site and off-site impacts of the proposed development. OK? V Comment: (11) Specifications of final development conditions such as, vegetative management, drainage, erosion c9+ rol, and buffer widths. OK? ✓ Comment: (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation./ OK? ✓ Comment: (13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature f existing and pro sed deve p'ment on the site. OK? Comment: Are the Documents signed and stamped? Type and#of License: C� 5V IL If not approved, what is the next action/recommendation for further acti �6 Reviewed by , on Time spent in review: SECOND REVIEW/UPDATE: Reviewed by , on Time spent in second review: THIRD REVIEW/ UPDATE: Reviewed by , on Time spent in third review: Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment Page 2 of 2 Form Effective June 2008 a Ong - 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 GINA KOEHL & BRIAN BREEDEN Parcel# 322345000014 Site Address 12921 NE NORTH SHORE RD, BELFAIR, WA 98528 (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 11-12 (b) A discussion of specific soil types Located on page(s) (c) A discussion of ground water conditions Located on page(s) 8 (d) A discussion of the upslope geomorphology Located on page(s) 7-8 (e) A discussion of the location of upland waterbodies and wetlands Located on page(s) 8 (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records Located on page(s) 10, 13-14 (2) A site plan, which identifies the important development and geologic features. Located on Map(s) FIGURE 2 (3) Locations and logs of exploratory holes or probes. Located on Map(s) FIGURE 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) FIGURE 2 (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details of proposed grade changes. Located on Map(s) FIGURE 4 (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) 15-17 (7) (a) Appropriate restrictions on placement of drainage features Located on page(s) 18 (b) Appropriate restrictions on placement of septic drain fields Located on page(s) 18 &27 (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) 20-22 Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. - 1 (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) 18 & FIGURE 2 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) 18 & FIGURE 2 (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) 20 (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) 19 & FIGURE 2 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 27 (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) COVERED IN POINTS 7-10 (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) 19 (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) FIGURE 2 I, Curtis D Cushman hereby certify under penalty of perjury that I am a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical Report, dated July 15, 2009 and entitled 12921 NE North Shore Rd, Belfair, Washington 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) Wash�� f nglneering Geologist 2439 ed Geo�o CURTIS DEA14 CUB. Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. J � O h J•. GEOTECHNICAL REPORT •t�'� ��o` 12921 NE NORTH SHORE ROAD BELFAIR, WASHINGTON PREPARED FOR GINA KOEHL & BRIAN BREEDEN BY GEOTECHNICAL TESTING LABORATORY OLYMPIA, WASHINGTON JULY 151) 2009 GROTECKNICAL TESTING LABORATORY CONTACT INFORMATION PREPARER INFORMATION GTL PROTECT NUMBER: 08-0273 CONTACT: CURTIS D.CUSHMAN ADDRESS: 10011 BLOMBERG STREET SOUTHWEST OLYMPIA,WASHINGTON 98512 TELEPHONE: (360)754-4612 FACSIMILE: (360)7544M EMAIL ADDRESS: CCUSHMAN@GEOTECHNICALTESTINGLAB.COM CLIENT INFORMATION CLIENT: GINA KOEHL/BRIAN BREEDEN TELEPHONE: (503)922-2079 BILLING ADDRESS: GINA KOEHL/BRIAN BREEDEN 1050511C PLACE NE KIRKLAND,WA 98033 SITE ADDRESS: 12921 NE NORTH SHORE ROAD BELFAIR,WASHINGTON 98528 PARCEL: 322345000014 GPS LOCATION: N47"21'33.38"W 123'02'23.32" 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 2 Phone#: (360)754-4612 Fax#:(360)7544848 SCOPE OF UNDERSTANDING Cb '-�'cogs GINA KOEHL/BRIAN BREEDEN 1050511C PLACE NE KIRJU AND,WASHINGTON 98033 RE: GEOTECHNICAL REPORT 12921 NE NORTH SHORE ROAD BELFAIR,WASHINGTON 98528 PARCEL 322345000014 N47o 21'33.38"W 123o 02'23.32" JuLY 15,2009 Dear Gina Koehl/Brian Breeden As per your 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 your review and distribution. A representative soil sample was submitted for laboratory testing from the project site(SL-1). The data have been carefully analyzed to determine soils bearing capacities and footing embedment depths. The results of the exploration and analysis indicate that standard spread footing as described in the text will be best to ensure a safe construction site. In the building area there is little variability in lithology as seen in the test hole,higher bluff, and on the property. Only the surficial soils in this area are addressed in this report. Net allowable soil pressures, embedment depth,and total expected settlements have been presented for the site later in the report. We are also a full service laboratory that can meet all your building, testing (compaction, asphalt, concrete), and inspection needs. We appreciate this opportunity to be of service to you and we look forward to working with you in the future. If you have any questions concerning the above items, the procedures used, or if we can be of any further assistance please call us at the phone number listed below. Respectfully Submitted, GEOTECHNICAL TESTING LABORATORY of W ash; fo Engineering Geologist 2439 @�Sed G eo�oo Curtis D.Cushman,L.G.,L.E.G. Senior Engineering Geologist CURTIS DEATH CUSHh9AN 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 3 Phone#:(360)754-4612 Fax#:(360)754-4848 GROTECHNICAL TmiNG 1LAaoPAToRv TABLE OF CONTENTS CONTACT INFORMATION 2 SCOPE OF UNDERSTANDING 3 INTRODUCTION 6 SITE CONDITIONS 7 SURFACE CONDITIONS 7 GEOLOGICALLY HAZARDOUS AREAS 9 LANDSLIDE HAZARD CLASSIFICATION 9 SEISMIC HAZARD CLASSIFICATION 9 EROSION HAZARD CLASSIFICATION 10 SITE SOILS 10 SITE GEOLOGY 11 SUBSURFACE EXPLORATIONS 13 SUBSURFACE CONDITIONS 13 RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL 13 SLOPE STABILITY AND ANALYSIS 14 SLOPE MODEL 16 RECOMMENDATIONS FOR BUILDING SETBACK 18 SEISMIC LIQUEFACTION HAZARD 18 GEOSEISMIC SETTING 19 RECOMMENDATIONS FOR EROSION CONTROL 19 VEGETATIVE MANAGEMENT 20 EARTHWORK 20 RECOMMENDATIONS FOR SITE PREPARATION 20 RECOMMENDATIONS FOR STRUCTURAL FILL 21 RECOMMENDATIONS FOR CUT AND FILL SLOPES 22 RECOMMENDATIONS FOR FOUNDATION SUPPORT 22 LATERAL EARTH PRESSURES 22 RECOMMENDATIONS FOR FLOOR SLAB SUPPORT 23 RECOMMENDATIONS FOR RETAINING WALLS 23 MASON COUNTY PRESCRIBED WALL DESIGN 25 RECOMMENDATIONS FOR RETAINING WALL ALTERNATIVES 27 RECOMMENDATIONS FOR SITE DRAINAGE 27 SEPTIC IMPACT 27 CONCLUSIONS AND RECOMMENDATIONS 28 GENERAL 28 REPORT LIMITATIONS AND GUIDELINES FOR USE 29 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 29 READ THESE PROVISIONS CLOSELY 29 REFERENCES 30 APPENDIX 32 LABORATORY ANALYSIS 33 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 4 Phone#:(360)754-4612 Fax#: (360)754-4848 GROTILCHNICAL TESTING LABORATORY SIEVE ANALYSIS 33 SHEAR @ SL-1 34 FIGURE 1 35 FIGURE 2 SITE PLAN Attached FIGURE 3 EROSION CONTROL NOTES Attached FIGURE 4 CROSS-SECTION Attached 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 5 Phone#: (360)7544612 Fax#: (360)7544848 GEOTECKNI AL TESTING LABORATORY INTRODUCTION This report summarizes the results of our geotechnical consulting services for the proposed replacement residence. The building would be constructed on a previously fully developed site. The report has been commissioned by Gina Koehl and Brian Breeden. The site is a narrow waterfront lot located on the southernmost side of Kitsap Peninsula overlooking Hood Canal. The site is approximately 5 miles by road east of Tahuya, Washington, and is accessed from an existing driveway serving multiple houses off Northeast North Shore Road. The location of the site is shown relative to the surrounding area on the Vicinity Map,Figure 1 (at the end of this report). Mama 39 m Ni NORTH SHORE RD -29 b' Our understanding of the project is based on our discussions with the client. We understand that the parcel is to be developed by replacing an existing two-storey residence with a new single-family residence. The new residence will be located upon the location of the pre-existing, but not on the identical footprint. In general, grading will limited to the development of the newer footings. 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. Geotechnical Testing Laboratory is therefore providing geologic and hydrogeologic services for the project. Specifically,our scope of services for this project includes the following: 1. A review of the available geologic,hydrogeological, and geotechnical data for the site area. 2. A geologic reconnaissance of the site area and surrounding vicinity. 3. Investigation and identification of shallow subsurface conditions at the site by characterizing the exposed soil,reviewing published well logs,and sapling. 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. Laboratory grain size and shear angle analysis for the soil samples collected from the site. 6. Evaluation of the landslide,erosion,and seismic hazards at the site per the Mason County Critical Areas Ordinance regulations(as of January 1,2007). 7. Building setbacks determined from static and dynamic slope stability modeling. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 6 Phone#: (360)754-4612 Fax#: (360)754-4848 8. 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(Figure 3). No slope on the site met the criteria of a landslide hazard area except for the road berm. However,the steep slope measured north of North Shore Road was within 300' of the building site. Therefore, Mason County requires that a geotechnical report be prepared in accordance with the Critical Areas Ordinance. 17.01.100ES (1) -- A discussion of general geologic conditions, specific soil types, ground water conditions, the upslope geomorphology and location of upland waterbodies and wetlands, and history of landslide activity in the vicinity. SITE CONDITIONS SURFACE CONDITIONS The proposed building site is located in an area of moderate residential development restricted to the shoreline of Hood Canal east of the Great Bend on Kitsap Peninsula near Tahuya, Washington. d4 l. -J � Facing North Facing South The site was inspected on July 2, 2009 by Curtis D. Cushman and Prashanta Lamichhane. The purpose of a site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. Curtis D Cushman and Vijay Chaudhary revisited the site to take a soil sample. Sampling provides representative material for laboratory testing. Photographs and visual observations were documented. Site- specific features were mapped and soil logs were recorded. The site is unvegetated except at the berm (the southern slope of the road. The term "berm" will be used throughout this report for lack of a handier term.). This is steep slope rising from the elevation of the residence to that of NE North Shore Road. The berm is covered by mature trees and other vegetation. There is grass and some plantings at the building elevation. The slope above the road is well vegetated with trees and other native plants. These consist of fir;alder,maple,and other indigenous trees,along with common shrubs and ferns. The center of the site will be developed with the new building. The building site is on a flat section stepped down from the road and sloping south of the building site gently to the water. . The overall property elevation ranges from 0 feet to 40 feet. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 7 Phone#: (360)754-4612 Fax#: (360)7544848 GROTECHNICAL TESTING LABORATORY The building site is flat, around 20 feet up. The slope above NE North Shore Road rises from 40 to over 140 feet. No groundwater is mapped. It is assumed to be at or near the level of the Canal. No erosion was seen on site. No surface water or ponding was observed at the building site. No slumping and sloughing was observed above the road. No evidence of deep-seated slope instability was observed on site or above the site. No seepage was noticed on slope or on site. Trees near and on the site were observed to be mostly straight and vertical with the exception of some oddly bent, mature trees on the top of the road berm. These may be bent by wind. Some trees show creep —caused bends,but these are mostly off property to the east. There is one upland water body of note, Lake Tahuya, located approximately one-half mile due north of the property. This appears to be a kettle or glacial-scour lake,with a maximum length of 1000 feet east-west. There is no apparent connection to any drainage leading to the property,and the lake is located on a north-slope, so surficial water would flow in that direction, away from the property. This does not pose a significant hazard. There are no nearby wetlands. No seeps were seen on the property or on the hillslope above. Seeps are locally abundant, primarily east of the property,but in no location to pose a hazard to the property. The steepest slope is along the berm from the building elevation to the road which is greater than 50 percent and is, at its maximum, approximately 15 feet high. This is a cut that is a design feature of the road. The slope above the road has a slope of approximately 40 percent. The building location and existing septic drainfield have a slope of approximately 5 percent or less. We consider the landslide hazard area to be above North Shore Road as on figure 2. The site is served by a community well which is located far from and topographically above both the building site and the existing septic drainfields. 17.01.100E5 (2) -- A site plan which identifies the important development and geologic features. A site plan is attached as Figure 2 Site Plan at the end of this report. 17.01.100E5 (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. A site plan is attached as Figure 2 Site Plan at the end of this report. 17.01.100E5 (3) -- Locations and logs of exploratory holes or probes. A location of the sample location(SL-1)hole is labeled on Figure 2 Site Plan at the end of this report. 17.01.100E5 (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. The area of the proposed development,boundaries of the landslide hazard area,and associated buffers and setbacks are demarcated on Figure 2 Site Plan at the end of this report. Appropriate geology is labeled on Figure 2 Site Plan. 09-0132 10011 Bloomberg Street SW, Olympia, WA 98512 8 Phone#: (360)754-4612 Fax#:(360)754-4848 GwrwnNICAE TE:STIN(; LABORATORY 17.01.100E5 (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. A cross-section is attached to this report as Figure 4 Cross-section. Minor cut and fill may occur after the publication of this report,which will not affect the cross section. GEOLOGICALLY HAZARDOUS AREAS LANDSLIDE HAZARD CLASSIFICATION The Mason County Critical Areas Ordinance(17.01.100A1)defines a landslide hazard area as: The following shall be classified as Landslide Hazard Areas: a. Areas with any indications of earth movement such as debris slides, eartli lows, slumps and rockfalls (see figure F.100). b. Areas with artificial oversteepened or unengineered slopes, i.e. cuts or fills. c.Areas with slopes containing soft or potentially liquefiable soils. d. Areas oversteepened or otherwise unstable as a result of stream incision, stream bank erosion, and undercutting by wave action. e. Slopes greater than 15%(8.5 degrees)and having the following: i. Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment or bedrock(e.g. sand overlying clay);and ii. Springs or groundwater seepage. f. Any area with a slope of forty percent or steeper and with a vertical relief of ten or more feet except areas composed of consolidated rock A slope is delineated by establishing its toe and top and measured by averaging the inclination over at least ten feet of vertical relief. The subject site meets the qualification of a landslide hazard area due to the adjacent slope that is greater than 40 percent and is more than 10 feet in vertical height(17.01.100A 1 f). SEISMIC HAZARD CLASSIFICATION The Mason County Critical Areas Ordinance(17.01.102A)defines a seismic hazard area as: 1. Areas susceptible to ground failure including the following: a.Areas with mapped geologic faults until proven inactive; b. Deep road fills and areas of poorly compacted art fcial fill; c.Areas with artificially steepened slopes (i.e. old gravel pits); d. Postglacial stream, lake or beach sediments; e. River deltas; f.Areas designated as potential Landslide Hazard Areas; g. Bluff areas; and h.Areas underlain by potentially liquefiable soils 2. The following criteria may be used as a guide by the County to indicate areas that have a higher likelihood of meeting the classification criteria above: a. Areas identified on the Coastal Zone Atlas of Washington, Volume 9, Mason County as Af, Qal, Qa2, Qvc, Qls, Qos and Qp. b.Areas identified on the Mason County Soil Survey Map as having slopes greater than 15 percent. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 9 Phone#: (360)754-4612 Fax#: (360)7544848 GEOTECHNICAL TESTING LABORATORY c. Faults identified on "Map Showing Known or Suspected Faults With Quaternary Displacement in the Pacific Northwest", A.M. Rogers, T.J. Walsh, W.J. Kockelman and G.R. Priest, US Geologic Survey, 1996, or described in "Active Faulting Investigations on the Canyon River Fault, Southern Olympic Range, Washington'; T.J. Walsh and KG. Neal, U.S. Geologic Survey, 1997. d. Areas underlain by potentially liquefiable soils as shown in "Liquefaction Susceptibility Map of Mason County, Washington"by Stephen P. Palmer, Sammantha L. Magsino, James L. Poelstra, Eric L. Bilderback, Derek S. Folger, and Rebecca A. Niggemann, September 2004 This site qualifies as a seismic hazard area because the site is categorized as, "l.f. Areas designated as potential Landslide Hazard Areas." The nearest mapped fault of any consequence is located in Hood Canal starting near Annas Bay and striking north- northeast up the Canal. This strike-slip fault is inferred and, according to DNR geologists familiar with the area, has never had sufficient movement to be seismically detected. There are no other mapped faults nearby; however, Western Washington is seismically active, and the new residence must be built to applicable earthquake standards. EROSION HAZARD CLASSIFICATION The purpose of the Erosion Hazard Section (17.01.104A) is to identify areas that present potential dangers to public health and safety, and to prevent the acceleration of natural geological hazards, and to neutralize the risk to the property owner from development activities. Areas in Mason County underlain by soils, which are subject to severe erosion when disturbed. Such soils include, but are not limited to, those for which potential for erosion is identified in the Soil Survey of Mason County, USDA Soil Conservation Service, 1960, or any subsequent revisions or additions to this source. These soils include, but are not limited to, any occurrence of River Wash ("Ra') or Coastal Beaches ("Cg') and the following when they occur on slopes 1 S%or steeper. a.Alderwood gravelly sandy loam ("Ac"and"Ad') b. Cloquallum silt loam("Cd') c. Harstine gravelly sandy loam ("HY9 d. Kitsap silt loam ("Kc') The soils at the site are mapped as Everett gravelly sandy 15 to 30 percent slopes. This is a moderately well drained sandy glacial till with some ash. This soil is further defined below. This site does not meet the technical criteria of an erosion hazard area but will be treated as such. SITE SOILS The soils on the building site leading from the water to the road berm are all developed and will not reflect the area mapping. The berm appears undisturbed, but the road above has been cut through original soils. The soil on the higher hill slope is seen to be thin and the cause of the scattered creep locations. The soil is shallow with respect to the underlying glacial materials(see below). No soil from berm or slope will be disturbed by the proposed project. For completeness,the soil is described as follows: The Soil Survey of Mason County, USDA Soil Conservation Service (1960) has mapped the site soil as the following: 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 10 Phone#: (360)754-4612 Fax#: (360)7544848 1 GROTECHNICAL TESTING LABORATORY Everett gravelly sandy loam, 15 to 30 percent slopes (Ek).-This soil is on the steeper slopes of glacial moraines. sides of gullies, and terrace fronts. It is closely associated with other Everett soils and the Aldenvood gravelly- sandy loams. This soil is more variable than Everett gravelly sandy loam. 5 to 105 percent slopes. The depth to substratum ranges from 12 to 36 inches, and the amount of gravel in the surface soil and subsoil varies greatly from place to place. Where the soil is in close association with the Alderwood soils, the substratum, in places. is compact and weakly cemented. Included are a few areas having slopes slightly greater than 30 percent. Use and suitability.-This soil is suitable only for forestry because it is strongly sloping, droughty. and lose in fertility. It is in capability subclass VIs and in site class 3 for Douglas-fir. This is the current mapping as provided by the USDA Web Soil Survey. The building site soils, if present, would be a slightly different nomenclature as this surface is relatively flat. SITE GEOLOGY Sample descriptions will be found in the appendix. All units are fully described below. The site is situated within the Puget Sound continental glacial zone. A series of events resulted in the mapped and visible geology seen on and around the site. The youngest material, and the unit of this site, is Qls, a landslide deposit. The next material is Qga, outwash material that precedes the advance of the glacier, such as stream deposits emergent from the base of the ice mass. This unit is not uncommon as the unit associated with deep landslide deposits along Hood Canal and Puget Sound. The lowermost deposits seen are Qapo, an outwash that was derived from Alpine (a general term for mountainous) glaciation. As these were overburdened by thick glacial deposits,they are commonly resistant and compact. All the following descriptions are from the Geologic Map of the Shelton 1:100,000 Quadrangle, Washington; by Robert L. Logan, 2003 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 11 Phone#: (360)754-4612 Fax#: (360) 754-4848 1 GEO'TE,CHNICAL TESTING LABORATORY � Qls Landslide deposits (Holocene)—Poorly sorted mixtures of locally derived rock and (or) soil emplaced by mass-wasting processes; deposits vary widely in size, composition, and mode of emplacement; only the largest landslides are shown; includes rock falls (Schuster and others, 1992) in the southeast Olympic Peninsula that are proba- bly seismically induced, and large deep-seated landslides along Hood Canal (Carson, 1976) and along steep-sided inner gorges of river val- leys in the southern Olympics; smaller shallow deposits such as debris flows in steep mountain drainages and rock topples along coastal bluffs, although numerous and dangerous, are too small to show at the map scale. c ga Advance outwalsh, late W isconsinan (Pie istocene)—Glaciofluvial sand and gravel and lacustrine clay, silt, and sand deposited during the advance of glaciers; sandy units commonly thick, well sorted, and fine grained, with interlayered coarser sand, gravel, and cobbles and silt rip-up lag deposits at their base; may contain nonglacial sedi- ments; generally overlain by till. :o Alpine outwash, pre—late Wisconsinan (Pleistocene)—Stratified sand, gravel, and cobbles; in the Quinault basin, clasts consist of o. :o. sandstone and less-abundant basalt from the Olympic Mountains core and peripheral rocks; in streams draining the southern and southeast- ern Olympics, clasts consist primarily of Crescent Formation basalt with less-abundant Olympic-core sandstone; may include peat, silt, and clay, and may be capped by weathered loess; clasts are generally more rounded than those in till and lack facets and striations; poorly to moderately sorted; gray to subtle yellow with wispy orange weath- ering. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 12 Phone#:(360)754-4612 Fax#: (360)754-4848 GROTECHNICAL TESTING LABORATORY Building upon old landslide deposits is common throughout the inland waterways of Washington State. The material deposited at the toe tends to protrude in a relatively flat deposit away from the steep hillside,and therefore presents an attractive location for development. This slide, while locally important, is not a massive one considering those mapped on the east side of Tahuya Bay, and, most recently, near Dewatto. What is of importance is if there are any signs of re-mobilization of the fault or other features of the landslide, and, in this case, none were noted. There appears to be no deep movement for 50 to 100 years, based on the maturity of the conifers. The lack of seeps is a good sign, and perhaps is explained by the landslide acting as an aquaclude. This may be seen especially in light of the seeps and springs seen to the east, in undisturbed Qga sediments. Nearby landslides, including the large one to the west of the property,do not represent an additional slide hazard to the property in this report. SUBSURFACE EXPLORATIONS Subsurface conditions at the site were evaluated by observing and logging the visible outcroppings of materials, which are well exposed above the road and in the lower road berm, probing, and reviewing available well logs and sampling by shovel. As this is an already developed site, the building location appeared to correspond to the general soil type in a cut state,or on compacted fill. The sample was collected as a grab composite taken along the base of the berm by shovel. The sample was sealed in a Ziploc bag, labeled, and transported to our soils laboratory. The soil gradation was determined by laboratory test method ASTM C 33 utilizing the Unified Soil Classification System (D 2487). The shear was by ASTM method D 3080. The soils laboratory has the following certifications,accreditations,or qualifications: AASHTO American Association of State highway and Transportation Officials AMRL AASHTO Materials Reference Laboratory CCRL Cement and Concrete Reference Laboratory A2LA American Association for Laboratory Accreditation ICC International Code Council SUBSURFACE CONDITIONS Beneath the Everett soil horizon, the site is underlain entirely by Qls, a landslide deposit. The gradation of the representative soil sample is included in the appendix. This sample was poorly graded sand with gravel(SP). The observed exposed soils and glacial materials are sands with varying amounts of gravel and silt with the latter in amounts that appears to be under 10%. This is consistent with landslide materials derived from the Qga or, indeed, the Qga itself. RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL The sample was evaluated by gradation to see if it qualified as structural fill material. Onsite soils may be considered for use as structural fill if industry standards are satisfied. Fill material requirements are found on page 9-31 of the WSDOT Standard Specifications 2008. 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. See the laboratory result in the Appendix. Care should be made is soils selection as these can vary across a site. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 13 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY SLOPE STABILITY AND ANALYSIS In general, the undisturbed native materials of the site consist of a mixture of variable amounts of silt, sand and gravel. These soil materials are in a dense condition except where they have been disturbed by weathering activity. No evidence of significant recent erosion was observed onsite at the time of our investigation. However, weathering and associated surficial erosion is seen confined to the upper weathered or disturbed zone, which has a lower strength. Creep was present,but spotty. Weathering, erosion, and the resultant surficial sloughing and landsliding are natural processes that affect slope areas. Significant weathering typically occurs in the upper 2 to 3 feet and is the result of oxidation, root penetration, wet/dry cycles, and freeze/thaw cycles. These processes can be managed and the risk reduced through proper construction of the residence. Erosion control recommendations in the slope and buffer areas are provided in the"Building Setback"and"Erosion Control'sections of this report. Excavation and back fillingwill occur n r cur based o appropriate riate engineering and earthwork recommendations found in Pp P g g the following"Earthwork" section. Grading in the building portion of the site should be conducted in accordance with geotechnical recommendations provided herein. The Coastal Zone Atlas, Volume 8, Mason County (MA-17) maps the site as an Unstable Recent Slide(URS). s , The Relative Sloe Stability of the Southern Hood Canal Area, Washington by Smith & f Carson (1977) has mapped the site as Class 3 _ & 4. The survey reads as follows: - Pahuva .k :4.0 s Class 3 is described as: Areas inferred to be unstable because �LZ..�#t- Si St C• 5 slopes, generally greater than IS 5 percent, are underlain by weak, SUBJECT SITE unstable materials in which old or ` recentlyactive landslides have r I •�' f' occurred. Includes areas of sand and -:; �'` _ � Al _ gravel on top of impermeable silt and y clay, mostly along steep valley sides. Class 4 is described as: Former landslide areas, generally within class 3 areas; include relatively large slumps,flows, and slides of soil, rock, and debris that have occurred since retreat of glaciers from the region (about 13,500 years ago). Present stability unknown, but sliding may be reactivated by excavations, slope modifications, or strong shaking. The site is most likely Class 4. No disturbance by construction is likely to occur,and,as noted above,the landslide area appears stable. 09-0132 10011 Bloomberg Street SW, Olympia, WA 98512 14 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY 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. Slope stability was modeled using the GeoStudio 2004 program (version 6.20) in both static and dynamic conditions (ca = 0.15). "Static" condition refers to an "as is" state of a given slope. "Dynamic" puts seismic acceleration into the model for earthquake conditions. Factors of safety were determined using Bishop's, Janbu methods. The site was modeled monolithically. A grab composite soils sample was used to determine cohesion and shear for the site. The parameters calculated from direct shear test are provided with this report. However site slope was modeled using conservative values assuming the materials on site as a result of landslide and is included in the slope model itself. Ground water table was not modeled based on our site investigation. The spread footings were not included in the models and surficial material may be ignored due to the fact some will be removed to reach the underlying material. Under static conditions, the slope remained stable to deep-seated and shallow failure. See Figure 4 for the cross- sections. Under dynamic loading (Ca=0.15), the 3328 computations demonstrated that the slope is safe and not susceptible to a deep-seated movement. The following are the Factors of Safety(FoS)attained for the section with respect to its current topographical representation. Section Factor of safe (Static) Factor of safe (Dynamic) A 1.664 1.272 These calculated Factors of Safety meet the requirements set forth by Mason County that is, 1.50 for static and 1.1 for dynamic loading scenarios. Based on our slope models representing critical slopes at the subject site, it is apparent that the building site is not susceptible to any deep-seated movements or instability. 09-0132 10011 Bloomberg Street SW,Olympia,WA 98512 15 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GroTRcnNtcAL TnTwc Lmaomvmv SLOPE MODEL SLOPE MODEL A �• STATIC FoS: 1.664 ,50 1N 30 ' ,20 „o ,00 C eo oo Name:SAND WI G L 70 Unit Weight:128 pcf w 50 Cohesion:200 psf 50 Phi:32° ao 30 20 10 a 100 200 300 �00 600 Distance 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 16 Phone#: (360)754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY SLOPE MODEL A ••� DYNAMIC • FoS: 1.272 1272 r O Name:SAND W/G L Unit Weight:128 pcf w Cohesion:200 psf Phi:32 a 100 zoo 300 400 14 Distance As can be seen,the road"berm"is the likeliest to fail,although the model shows this to be within the Factors of Safety. Bear in mind that all other test surfaces, including those in the bank above the road,have even higher Factors of Safety. Please note that the models use a coefficient and 0 angle less than the numbers derived from the shear test and, hence,the Factors of Safety are conservative. 09-0132 10011 Bloomberg Street SW, Olympia, WA 98512 17 Phone#: (360)754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY 17.01.100ES (7) -- Appropriate restrictions on placement of drainage features, septic drain fields and compacted fills and footings, including recommended buffers and setbacks from the landslide hazard areas. These will be addressed in the sections below. 17.01.100ES (11) -- Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. RECOMMENDATIONS FOR BUILDING SETBACK The building setback may be measured from the bottom of the footing to the face of the steep slope in accordance with the International Building Code (1805.3.1),see figure to right. As previously discussed, weathering, erosion and the resultant surficial sloughing and shallow landsliding are natural processes that affect slope Setback areas. Slumping and sloughing were not observed at the building site. Recommendations are limited to the building site as much, if not all, of the area to the north of the site is not in the control of the property owner. To manage and reduce the potential for erosional processes,we recommend the following: ➢ No drainage of concentrated surface water or significant sheet flow onto building site ➢ Usual concerns for the septic drainfield are not involved. The drainfields are pre-existing and will not be altered. ➢ Preserve existing vegetation. ➢ The setbacks and buffers are shown in the site plan. SEISMIC LIQUEFACTION HAZARD The following geologic excerpts are from the available resources governing seismic liquefaction susceptibility of the subject site. 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 low to moderate 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 D. Site class D is a stiff soil(IBC). Based on our review of the exposed soils, we conclude that the site is somewhat susceptible to liquefaction. The near-surface soils are generally in a dense condition and the static water table is located at a sufficient depth below the surface so that shaking of the already dense soil is not apt to produce a denser configuration and subsequently excess pore water pressures are not likely to be produced. 09-0132 10011 Bloomberg Street SW, Olympia, WA 98512 18 Phone#: (360)754-4612 Fax#: (360)754-4848 GE®TEcnNtL TTING LABORATORY GEOSEISMIC SETTING According to the Seismic Zone Map of the United States contained in the 2006 International Building Code(IBC), the project site is located where the maximum spectral response acceleration is 45 percent of gravity(g). We recommend following seismic factors for design purposes. • Site Class: D(stiff soil) • Spectral response acceleration, short period(SMs): 1.25g(Fa= 1.0) • Spectral response acceleration, 1-second period(Smi): 0.70g(F,,= 1.55) 17.01.100E5(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. RECOMMENDATIONS FOR EROSION CONTROL No surface erosion was observed on or surrounding the subject site with the exception of the soil creep noted above. No ponding from rain run-off was observed onsite. It is our opinion that the potential erosion hazard of the site is not a limiting factor for the proposed development. Removal of natural vegetation should be minimized and limited to the active construction areas. Landscaping around the home is permissible,but understory growth on the road berm should be encouraged as much as possible as a deterrent to erosion. Hazard trees located on steep slopes may be removed only if the stumps remain to deter erosion. Erosion mitigation above the property on the upper slope is out of the area of control of the clients. Temporary and permanent erosion control measures should be implemented and maintained during construction and/or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential receiving waters. Revegetation should occur immediately following construction. Erosion control measures should include, but not be limited to, silt fences, berms, and swales with ground cover/protection in exposed areas. Typical erosion control notes and a silt fence detail are included on Figure 2 Site Plan. No re-contouring of the site is anticipated. 17.01.100E5(12) -- Recommendations for the preparation of structural mitigation or details of other proposed mitigation. No structural mitigation is predicted for this project. The current residence will be demolished and replaced. The preexisting septic locations will be retained. 17.01.100E5(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. Please see below. 09-0132 10011 Bloomberg Street SW,Olympia,WA 98512 19 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAE TESTING LABORATORY VEGETATIVE MANAGEMENT The required vegetation buffer of 50 feet lies wholly off the client property to the north. Some vegetation recommendations are located elsewhere in the report (such as Erosion Control above). These recommendations and the following are general and maybe modified subject to approval. A revegetation plan should be in place before the end of construction. Native species should be considered as the primary vegetation in areas away from lawn and ornamental plantings. These should be left alone wherever possible. Shallow rooted species, such as grass, should be planted closer than 10 feet from underground drainages, septic drainfields and their associated drains,etc. 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. If applicable,"no disturb"zones should be marked on final plans and flagged at the job-site Clearing of vegetation must be kept to a minimum and be limited to the area of the structures and construction support. The owner may remove trees within 15 feet of structures that require future access as well as those with damaged roots from the construction procedures. Conifers should not be topped. The choice of native vegetation and the planting locations should be provided by a professional horticulturist. EARTHWORK RECOMMENDATIONS FOR SITE PREPARATION All areas to be excavated should be cleared of deleterious matter including any existing structures,debris,duff,and vegetation. Based on our observations, we estimate that additional stripping on the order of 12 inches will be necessary to remove the root zone and surficial soils containing organics. Some deeper stripping locally should be anticipated. No deeper excavation is expected at the building site except along the proposed foundation additions. However, any material that is excavated may be stockpiled and later used for structural fill, erosion control, and/or landscaping. Surficial material unsuitable for these tasks should be removed from the project site. No foundation elements shall be constructed on"untested"fill material. Where placement of fill material is required, the exposed subgrade areas should be proof-rolled to a firm and unyielding surface prior to placement of any fill. Over-excavation in any building area should be backfilled with structural fill,compacted to the density requirements described in the"Structural Fill"section of this report. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 20 Phone#: (360)754-4612 Fax#: (360)754-4848 GE©TECHNICAL 7 "TING ]LABORATORY If structural fill is needed, we recommend that a member of our staff evaluate the exposed subgrade conditions after removal of vegetation and topsoil stripping is completed. Any soft, loose or otherwise unsuitable areas delineated during foundation preparation or probing should be compacted, if practical, or over-excavated and replaced with structural fill, based on the recommendations of our report. RECOMMENDATIONS FOR STRUCTURAL FILL All fill material should be placed as structural fill. The structural fill should be placed in horizontal lifts of appropriate thickness to allow adequate and uniform compaction of each lift. Fill should be compacted to at least 95 percent of MDD(maximum dry density as determined in accordance with ASTM D-1557)to grade. The appropriate lift thickness will depend on the fill characteristics and compaction equipment used. We recommend that the appropriate lift thickness be evaluated by our field representative during construction. The suitability of material for use as structural fill will depend on the gradation and moisture content of the soil. As the amount of fines (material passing No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult to achieve. During wet weather,we recommend the use of well-graded sand and gravel with less than 10 percent(by weight)passing the No. 200 sieve based on that fraction passing the%-inch sieve. If prolonged dry weather prevails during the earthwork and foundation installation phase of construction, a somewhat higher(up to 10 percent)fines content will be acceptable. 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. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 21 Phone#: (360)754-4612 Fax#: (360) 754-4848 GaoTacHNICAL TmiNG UsomToRy RECOMMENDATIONS FOR CUT AND FILL SLOPES All job site safety issues and precautions are the responsibility of the contractor providing services and/or work. The following cuttfill slope guidelines are provided for planning purposes. The following are guidelines for use if needed. Temporary cut slopes may be necessary following demolition of the existing structure. As a general guide, temporary slopes of 1.5 to 1 (horizontal to vertical) or flatter may be used for temporary cuts in the upper 3 to 4 feet of the glacially consolidated soils that are weathered to a loose/medium-dense condition. Temporary slopes of 1 to 1 or flatter may be used in the unweathered dense to very dense sands and gravel. These guidelines assume that all surface loads are kept at a minimum distance of at least one half the depth of the cut away from the top of any slopes and that significant seepage is not present on the slope face(due to recent rain events). Flatter cut slopes will be necessary where significant raveling or seepage occurs. Surface drainage should be directed away from all slope faces. Straw, hay, or jute matting shall be used to cover the exposed soils until permanent vegetation is established. All slopes should be seeded as soon as practical to facilitate the development of a protective vegetative cover,or otherwise protected. RECOMMENDATIONS FOR FOUNDATION SUPPORT Where foundation elements are located near slopes between 5 and 30 percent, the footings should be located a minimum of 2 times the footing width from the slope face (horizontally), and founded in medium dense or denser native soils or properly prepared structural fill. We recommend the footing depth should be at least 12-inches and/or correspond to the preexisting footings. We recommend a minimum width for isolated and continuous wall footings to meet IBC 2006. Footings founded as described above can be designed using a net allowable soil bearing capacity of 2,000 psf (pounds per square foot)for combined dead and long-term live loads in areas of medium dense to dense soils. The weight of the footing and any overlying backfill may be neglected. The allowable bearing value may be increased by one-third for transient loads such as those induced by seismic events or wind loads. We estimate that settlements of footings designed and constructed as recommended will be less than 1 inch,for the anticipated load conditions, with differential settlements between comparably loaded footings of'/z inch or less. Most of the settlements should occur essentially as loads are being applied. However, uncorrected disturbance of the foundation subgrade during construction could result in larger settlements than predicted. LATERAL EARTH PRESSURES Lateral loads may be resisted by friction on the bases of footings and floor slabs and as passive pressure on the sides of footings. An allowable coefficient of friction of 0.45 may be used to calculate friction between the concrete and the underlying soil. We recommend the following be used to determine the lateral earth pressures: • �(soil friction angle) 50 degrees • Ko(at rest earth pressure coefficient) 0.25 • Ka(active earth pressure coefficient) 0.15 • Kp(passive earth pressure coefficient) 6.67 • y(soil unit weight) 128 pcf 09-0132 10011 Bloomberg Street SW,Olympia,WA 98512 22 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTILCHNICAL 7 STING ILABoRAToiky RECOMMENDATIONS FOR FLOOR SLAB SUPPORT Slabs-on-grade should be supported on medium dense or dense native soils or on structural fill prepared as described in the "Structural Fill" section of this report. We recommend that floor slabs be directly underlain by a synthetic vapor barrier. Below the synthetic vapor barrier, we recommend a minimum 4-inch thickness of coarse sand and/or gravel containing less than 5 percent fines (by weight). The drainage material should be placed and compacted to an unyielding condition. A synthetic vapor barrier must be used for the control of moisture migration through the slab, particularly where adhesives are used to anchor carpet or tile to the slab. A thin layer of sand may be placed over the vapor barrier and immediately below the slab to protect the liner during steel and/or concrete placement. The lack of a vapor barrier could result in wet spots on the slab,particularly in storage areas. RECOMMENDATIONS FOR RETAINING WALLS Although not anticipated for this project,the following section is included for completeness. Retaining walls may be considered on the uphill sloping portion of the site to retain fill material. The lateral pressures acting on the subgrade and retaining walls will depend upon the nature and density of the soil behind the wall. It is also dependent upon the presence or absence of hydrostatic pressure. If the adjacent exterior wall space is backfilled with clean granular, well-drained soil (washed rock),the design active pressure may be determined using an active pressure coefficient equal to 0.25 (Ka=0.25). This design value assumes a level backslope and drained conditions as described below. Retaining walls located on or near the toe of a slope that extends up behind the wall should be designed for a lateral pressure, which includes the surcharge effects of the steep slope in proximity to the wall. If required, the following data can be used as a guideline for the retaining wall construction. For an irregular or composite slope, the equivalent slope angle may be determined by extending a line upward from the toe of the wall at an angle of 1 to 1 (Horizontal to Vertical)to a point where the line intersects the ground surface. The surcharge effects may be modeled by increasing the equivalent fluid pressure for flat ground by the percentage given in the following table: SLOPE INCLINATION:EQUIVALENT FLUID PRESSURE Slope Angle Percent Increase Equivalent Fluid Pressure Horizontal 0% 35 pcf 3H:1 V 25% 44 pcf 2H:1 V 50% 53 pcf 1 H:1 V 75% 61 pcf If the walls are greater than 4 feet in height, exclusive of the footing, additional design considerations should be applied. Walls greater than 4 feet in height must be designed by a Professional Engineer. Positive drainage, which controls the development of hydrostatic pressure, can be accomplished by placing a zone of coarse sand and gravel behind the walls. The granular drainage material should contain less than 5 percent fines. The drainage zone should extend horizontally at least 18 inches from the back of the wall. The drainage zone should also extend from the base of the wall to within 1 foot of the top of the wall. The drainage zone should be compacted to approximately 90 percent of the MDD. Over compaction should be avoided as this can lead to excessive lateral pressures. 09-0132 10011 Bloomberg Street SW,Olympia,WA 98512 23 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY A perforated PVC pipe with a minimum diameter of 4 inches should be placed in the drainage zone along the base of the wall to direct accumulated water to an appropriate discharge location. We recommend that a non-woven geotextile filter fabric be placed between the drainage material and the remaining wall backfill to reduce silt migration into the drainage zone. The infiltration of silt into the drainage zone, with time can reduce the permeability of the granular material. The filter fabric should be placed in such a way that it fully separates the drainage material and the backfill, and should be extended over the top of the drainage zone. Lateral loads may be resisted by friction on the bases of footings and as passive pressure on the sides of footings and the buried portions of the wall. Please see the lateral earth pressures section of this report for recommendations. Mason County has provided a prescribed retaining wall design that may be used for non-bulkhead retaining walls less than 4 feet in height. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 24 Phone#: (360) 754-4612 Fax#: (360)754-4848 I GROTECHNICAL TESTING LABORATORY MASON COUNTY PRESCRIBED WALL DESIGN MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Mason Counly Bing.111.426 West Cedar Street PO Box 186,Shelton,WA 98584 mmoo.mason.wa.us (3W)427-9670 Belfar1.30052?_-4487 E:r,a :'_rC;482-`_•_b2 UPLAND CONCRETE DesignPrescriptive DESIGN STANDARDS DO NOT APPLY TO SHORELINE EROSION CONTROL BULKHEADS vo CP'6' l T �• Slope less than or equal to 1:1 - -- lit- -S-B+1F5 1 I i i I 1 I 1 i ;_ —4_--4-- I a PROVIDE FLOOD 1 I I 1 I Ff2ii�1F C�`SATINr, I I I i I �l'rlalheOrack �_-F- -1--_-t---t-- VI- 2.0 GAINS- I 1 1 I I 1 I I . BAF AT 12' O.C. 1 Fitef'attic I 1 1 j I 1 I I 41 BARS SJ7FACE J7 _'pe*rcrated pipe 1 1 1 I I 1 1 I _ -r am Oaylignte anGrade to b= 1 min. - r. ,,�..t� �pprp,�c;ccC'C Vl 3n. °' I I 1 1 1 I 1 1 1 III �' 5 I I 1 1 1 1 I 1 1 FOCUrIgS -16-j �v = placetl own LSI-+ESR KEY 8-6:sRS fIrMr nal?.,e l.lSE 2t<!. Soil K NCICK.OT EL E14ATION B NOTE SECTr0N SPACINI; CIF S-E'1'RS ISGPFRrxIMr1TE USE TA61JL4R NJMBER OF 6aRS e.N] SPACE EVErrLY we 2' COVER, a- H _ T '.O_:DNG BCLPE _EhflTHA BA e- BARS REINFORCEMENT FT F7-IN N ;DE'!FT 92E %'S_iYG Y1-EA.FE _-BARE 612E 5o.L1"G LEND— x SIZE arwlDrr LBa PEA FOOT 4.3 .3 0.30 1fr i[r Ts — 1 _ 3- 311Ir 11 ?9' t •3 1 5.0 10 0.36 L2• P• 81.4' — t _ 4'-8' 1-. ?-9' 5-0 i2 0A7 S'8• -T 9ti9" 09-0132 10011 Bloomberg Street SW, Olympia, WA 98512 25 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY Prescriptive Concrete Retaining Wall DEsrA p g , .,. Do NaT APPLY To SHOREUNE ERDsKiN , Height.Maximum Eight Feet Upland concrete retaining walls installed in accordance with the prescriptive design shown on the reverse side need not be designed by an engineer unless the Mason County Building Dept. detern-kines special conditions exist. Any retaining wall exceeding eight feet in height or varying from the prescriptive design requires an engineered design. Location of Retaining Wall Retaining walls must only be placed against stable slopes, consisting affirm,undisturbed soil. Drainage must be provided as shown with a 4'perforated drain pipe or 2`weep hates spaced not less than 12 feet on center. No surcharge load,such as a building or driveway;may be placed on the retaining wall or within a distance equal to the vertical height of the retaining wall unless an engineered design is prepared for the adddionai load. Ground Surface Above Retaining Wall The ground surface above the retaining wad shall be less than or equal to 1.1 (i.e. 1-foot vertical to 1-foot horizontal). Retaining Wall Placement The top of the footing for the retaining wall must be set a minimum of 12 inches below grade. The foaling and wall dimensions shall not be less than outlined in the retaining wall chart. The footing shall be placed on firm,undisturbed earth. Drainage A minimum of 12 inches of washed granular drainage materia shall be placed between the undisturbed soil and the retaining wall. The drainage matenals must be composed of gravel with 1-inch particle sizes. Two-inch weep holes shall be located approximately 6-inches above grade, below the granular drainage material: spaced not less than 12-feet on center. At the base of the wall, a perforated drain pipe,with at least a four4nch diameter,shall be installed within the drainage materials. The drain pipe must drain to a point of discharge,approved by Mason County. Inspections Prior to the placement of concrete,the builder must schedule an inspection of the fomrwork and reinforcement placement for the retaining wall footing. During the first inspection,the inspector will verify the soil condition,footing dimensions,footing reinforcement,and footing placement as well as the provisions for drainage. At the next inspection,the inspector shall verify the wall dimensions and reinforcement prior to the wall pour. A final inspection nwst be performed once al work is complete. To schedule an inspection call the Mason County 24-hour recorded inspection request line at(360)427- 7262. Inspections can also be requested online at: www_co.mason.wa.us or by fax at(360)427-7798. When requesting an inspecbbn please provide the following information. 1)Name on permit 2)type of inspection 3)Permit number 4)Site Address 5)Type of permit 6) Date inspection requested and 7)Name and phone number of caller. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 26 Phone#: (360)754-4612 Fax#: (360)754-4848 RECOMMENDATIONS FOR RETAINING WALL ALTERNATIVES Typically, block wall systems are more cost effective for long-term walls than the other options. Specific design criteria for these options can be provided at your request by the block manufacturers. RECOMMENDATIONS FOR SITE DRAINAGE All ground surfaces,pavements and sidewalks should be sloped away from the residence and associated structures. Surface water runoff should be controlled by a system of curbs, berms, drainage swales, and/or catch basins and tight-lined into the appropriate drainage facilities. We recommend that conventional roof drains be installed. Footing drains shall be installed for the proposed structure. The roof drain should not be connected to the footing drain. For footing drains, the drain invert should be below the bottom of the footing. Typical drainage control measures are included on Figure 3. Use of existing drainages is preferred.. Onsite irrigation to lawn areas shall be minimized. As no native plants should be disturbed, revegetation can be done by the clients based on the abovementioned criteria. 17.01.100ES (10) An analysis of both on-site and off-site impacts of the proposed development. SEPTIC IMPACT The proposed septic drainfield will be located in the north portion of the site and to the north of the proposed building locations. This is a pre-existing septic system from the original residence that is being retained for the proposed building. We conclude the stability of the site will not be adversely impacted by the septic drainfield and the septic drainfield will not be adversely impacted by the landslide hazard area. We also conclude the septic drainfield will not adversely impact the proposed structure. 09-0132 10011 Bloomberg Street SW,Olympia,WA 98512 27 Phone#: (360)754-4612 Fax#: (360)754-4848 GILoTacnNicAL TrsTING LABORATORY CONCLUSIONS AND RECOMMENDATIONS GENERAL 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 proposed building location is stable relative to deep- seated instability and will not be affected by the proposed structure. The proposed structure will not undermine adjacent slopes. Proper drainage control measures will reduce or eliminate the potential for erosion in this area. The project will cause no significant environmental impact for the life of the project. If tested and confirmed,the onsite soils may be suitable for use as structural fill material. Saturated soil conditions may be associated with these soils during or following extended periods of rainfall. However, to reduce grading time and construction costs,we recommend that earthwork be undertaken during favorable weather conditions. Conventional construction equipment may be utilized for work at the site. Conventional spread footings may be utilized at the site for support of the structure. We do recommend that roof and footing drains be installed for the structure with conventional spread footings. A vapor barrier is recommended for all slabs-on-grade. Conventional spread and continuous wall footings appear to be the most suitable type of foundation for the support of the proposed structure. 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 28 Phone#: (360) 754-4612 Fax#: (360)754-4848 GawacnmcAL TrsTwc. LABORATORY REPORT LIMITATIONS AND GUIDELINES FOR USE We have prepared this report for the exclusive use of Gina Kohl,Brian Breeden,and their authorized agents for the proposed single-family residence in Mason County, Washington. Site inspections, research, and mapping have culminated in this report. This report is intended to meet the requirements of the Mason County Critical Areas Ordinance. This report does not specify setbacks for: line-of-sight setbacks, FWHCA setbacks, eagle tree setbacks, wetland setbacks, or property line setbacks. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, expressed or implied, should be understood. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to onsite personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals, and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments, claims and disputes. Geotechnical Testing Laboratory includes these explanatory "limitations" provisions in our reports to help reduce such risks. Please confer with Geotechnical Testing Laboratory if you are unclear how these "Report Limitations and Guidelines for Use"apply to your project or site. The equipment, techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, geotechnical engineering or geologic reporting does not usually relate any environmental findings,conclusions or recommendations;e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. 09-0132 10011 Bloomberg Street SW, Olympia,WA 98512 29 Phone#: (360)754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY 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. Logan (2003), Geologic Map of the Shelton 1:100,000 Quadrangle, Washington, (Open file report 2003-15),by published by Washington State Department of Natural Resources. Noble and Molenaar (1970), Geologic Map of Southeastern Mason County, Washington, Water Supply Bulletin 29, Plate 1, Published by Washington State Department of Water Resources Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann (September 2004), The Liquefaction Susceptibility Map of Mason County, Washington, published by Washington State Department of Natural Resources. Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004), The Site Class Map of Mason County, Washington,published by Washington State Department of Natural Resources. Rogers, A. M., Walsh, T. J., Kockelman, W. J., and Priest, G. R. (1996), Map showing known or suspected faults with quaternary displacement in the Pacific Northwest, published by U.S. Geological Survey OFR 91441-0, 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. Dragovich, Logan, Walsh, and Schasse(2002), Geological Map of Washington-Northwest Quadrant(Geological Map GM- 50),published by Washington State Department of Natural Resources. Walsh (1997), The Canyon River fault, an active fault in the southern Olympic Range, Washington: Washington Geology, v. 25,no.4,p.21-24,published by U.S.Geological Survey. Washington State Department of Ecology (1979), Coastal Zone Atlas of Washington, Volume 9, published by Washington State Department of Ecology. PUBLICATIONS Ambrose(1981),Simplified Design of Building Foundations,Table 2.5,pages 48-57,published by John Wiley&Sons,Inc. ASTM International(2005),Annual Book of Standards 2005, Section 4, Volume 4.08,published by ASTM International, West Conshohocken,Pennsylvania. Bloom(1991),Geomorphology,published by Prentice-Hall, Inc.,Upper Saddle River,New Jersey. Gallagher, Patricia M. (October 27, 2000), Passive Site Remediation for Mitigation of Liquefaction Risk, Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University,Virginia. International Code Council,Inc.(2004),2003 International Building Code,published by International Code Council,Inc. International Code Council,Inc.(2006),2006 International Building Code,published by International Code Council,Inc. 09-0132 10011 Bloomberg Street SW,Olympia,WA 98512 30 Phone#: (360) 754-4612 Fax#: (360)7544848 GEOTECHNICAL TESTING LABORATORY Kollmorgen Instruments Corporation (1994), Munsell Soil Color Charts (1994 Revised Edition), published by Macbeth Division of Kollmorgen Instruments Corporation,New Windsor,New York. McCarthy(1993), Essentials of Soil Mechanics and Foundations, published by Prentice-Hall, Inc.,Upper Saddle River, New Jersey. Moffit(1992),Surveying 9'4 Edition,published by Harper Collins,New York,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. Washington State Department of Transportation (WSDOT)(2005), Standard Specifications for Road, Bridge, and Municipal Construction 2006 M41-10,prepared by WSDOT Engineering Publications,P.O.Box 47408,Olympia,Washington. WEBSITES Mason County Government Information Services (http://www.co.mason.wa.us) Mason County Codes,Ordinances,and Regulations (http://www.co.mason.wa.us/code) Puget Sound Lidar Consortium (http://pugetsoundlidar.ess.washington.edu/lidardata/index.htmi) Slope Stabilization Erosion Control Using Vegetation A Manual of Practice for Coastal Bluff (http://www.ecy.wa.gov/biblio/9330.html) Vegetation Management Guide for Puget Sound Bluff Property Owners (http://www.ecy.wa.gov/biblio/9331.html) United States Department of Agriculture Natural Resource Conservation Service (http://soildatamarLnres.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) 09-0132 10011 Bloomberg Street SW,Olympia, WA 98512 31 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY APPENDIX 09-0132 10011 Bloomberg Street SW, Olympia,WA 98512 32 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNIC AL TUTING ILABoRAToky LABORATORY ANALYSIS SIEVE ANALYSIS U.S.Standard Sieve Opaning in Inches U.S.Standard Sie-,v Numbers livdiometer R--sults 100% !i . " 10 16 20 W AO SM 2DD D% 90% ----------------------- --------------- ------ 10% ------------ ---- ---------------------------------------------- 80% ---------------------------------------- - ------------------------------------------------------------------------------------------- 20% 70% ------------------- ----------------T ----------------------I---------------------I-----------------------T--------------- ------ 30% -1---------------------- rr ------------- - ---------- 0 60% ----------------------------------------------T------ ----------------r------------------------------------------------------------------- 40% CD50% --------------------- --------------------- --------- ---------- -------------------- --------------------- --------------------- 50% '0 --- --------- --- -- 40% ------------------- --------------------- --------------- ------------------------- ------------------------------------------ 60% 41 CU 30% --------------------- ---------------------t--------------------- ------------------- --------------------- --------------------- 70% 20% --------------------- --------------------- -------------------- 80% ----- ------------- ---------------------t--------------------- 10% ---------------------t--------------------- ------------ ------ ---------------------t------------------- - 90% 1 .1 1 -id 100% 100 10 1 0.1 0.01 0.001 Grain Size in Millimeters Cobbles Gravels Sands Silts Ci-Y Coarse I Fine Coarse Medium I Fin. I l Date 07 08 09 Dje.= 0.24 Classification P-o Gravel Sample* 344 D30= 0.94 SP:Poorly graded Sand v6ith Gravel 42.870-o Sample ID: Sand w,,Crravel D60= 5.66 Specifications %Sand Source: On Site Cc= 0.65 No Specs 53.86% Project: 12921 North Shore Rd. C,- 23.34 %Moisture#DrV 0! %Silt&Clay Client: Brian Breeden Liquid Limit= 0.00 hest Ratio= 3.28% AST 1.10: C-33 Plastic Limit= 0.00 Fineness Modulus Sample Meets Specs Depth: SL-1 Plasticity Index= 0.00 4.60 Yes Coarse Actual ':Interpolated fines Actual jnterpolat--d Section Cumulative Cumulative Section Cumulative Curni;lative 'Sieve............ .. ................ I Percent Percent Sped ......Specs..... ............'SievePercent Percent ....... .....; Specs US Metric Passme Passim Max Min us Metric Passing Passing Max Min 6.00" 150.00 i 100.0% ;44 4.750 57.1% 57.1% 4.00" 100.00 1 100.0% I 48 2.360 44.6% 44.6% 3.00" 75.00 100.0% 410 2.000 41.41A 2.50" 63.00 100.01/0 416 1.180 34.06% 34.0% 2.00" 50.00 100.0% 420 0.850 28.4% 1.75" 45.00 100.00% i 030 0.600 24.2% 24.2% 1.50" 37.50 100.0% W 1 0.425 17.41% 1.25" 31.50 93.2% 93.2% 450 0300 12.5% 12.5% 1 1.00" 25.00 90.3% 90.3% 460 J 0.250 10.3% 7/8" 22.40 89.7% ino 0.180 7.3% 4100 0.150 6.0% 6.0%3/4" 19.00 89.01% 89.00/9 5/8. 16.00 84.0% 4140 0.106 4.4% UT' 1 12.50 1 78.3% 78.3% i$170 1 0.090 3.8% 3Y8" 9-50 72.1% 72.1% :0200 0.075 33% 33% 14" 6.30 62.01% 4270 0.053 Copyright;Spoor:Engineering&Technical Service,,PS,1386-2004 09-0132 10011 Bloomberg Street SW, Olympia, WA 98512 33 Phone#: (360) 754-4612 Fax#: (360) 754-4848 SHEAR @ SL-1 Peak Shear Stress vs. Normal Stress 30�. I Shear=50° 2000 N c ffi 2 N Y R a 1000 —f 1/4ton 500 1/2ton �1ton Cohesion =300 psf 0 0 500 1000 15W 20W 2500 3000 Normal Stress(psQ 09-0132 10011 Bloomberg Street SW, Olympia, WA 98512 34 Phone#: (360) 754-4612 Fax#: (360) 754-4848 C '+OTECHNICAL TESTING LABORATORY FIGURE 1 Itl � giy' 1�,h ToiuYa $fuZ► °�� 0 bq \ �D" \ —- ---- i C l.• Iq AY points c� � L R° SUBJECT SITE N P 1 1 FOOL Brf G \ - f rI L ,t-- ��_��{�, =-i- �• Amy} .. _ i i. _ n $ an 1-. t IT T 09-0132 10011 Bloomberg Street SW, Olympia,WA 98512 35 Phone#:(360) 754-4612 Fax#: (360)754-4848 THE SITE PLAN WAS PROVIDED BY LISA CURTIS C MATERIAL BPMADE ROLLS '�ORYNRE RING TO ATTACH Geotechnical RE THE CONTOURS ARE BASED ON MASON COUNTY GIS DATA 2 zzx"°Au°E RE AND OUR FIELD EXPLORATION CONDUCTED BY CURTIS D CUSHMAN& FABRIC OR EQUIVALENT PRASHANTA LAMICHHANE ON JULY 2,2009. Testing FACE /T\ Laboratory BURY BOTTOM OF FILTER MATERIAL IN S'X1 T TRENC S' 7-0' S.T iT S'MIN �- 2"X4 WOOD POSTS ALT:STEEL FENCE POSTS Geotechnical Services QA/QC Services LIMIT OF LANDSLIDE HAZARD ARI CONTINUOUS ROLL Cur TO BE OF JOINTS.WHEN JOINTS Testing Services SPLICED TOGETHER ONLY AT OVERLAP AND SECURELY 3 FEET APART AND DRIVEN IF 30INCHES). MATE LYSINCHESWDEAND12 10011 Blomberg St.SW _AND UPSLOPE FROM THE BARRIER. Olympia,WA 98512 IC IS USED,A WIRE MESH Phone:(360)754-4612 :URELY TO THE UPSLOPE SIDE STAPLES AT LEAST I INCH Fax:(360)7544848 !E SHALL EXTEND INTO THE ,LL NOT EXTEND MORE THAN 35 50'VEGETATIVE BUPRFACE. SHALL BE STAPLED OR WIRED Date: 07/15/2009 SHAXTENDED T EXTEND L RE EMORE THAN 38 Designed by: LISA CURTIS JRFACE.FILTER FABRIC SHALL Drawn by:VC ND CLOSER POST SPACING IS Checked by: CDC LAP BE ELIMINATED,IN SUCH Dyy #:07-15-09-011 R WIRED DIRECTLY TO THE 9 1BOVE NOTES APPLYING. MOVED BEFORE THE UPSLOPE D. TIED IMMEDIATELY AFTER EACH , IOLONGED RAINFALL.ANY D ATELY 124'SETBAC IN PLACE PRIOR TO THE UECT ENGINEER AND THE COUNTY LLATION OF BEGINNING CONSTRUCTION. .IMITED TO THE ITEMS ' 'ONSIBLE FOR THE .EROSION CONTROL MEASURES. I DRAINAGE FACILITIES EN TO PREVENT MIGRATION PROJECT NAME: RVEILLANCE OF ALL EROSION KOEHL-BREEDEN SITE EIE ARYCONTRPAIRSACTOR OR SHADDITIO I 12921 NE NORTH SHORE RD ES CONTRACTORSIWLLPROVIDE :SAS DETERMINED.FAILURE BELFAIR,WASHINGTON PROJECT ENGINEER.FAILURE EROSION CONTROL IJETIES BEIR, LENED PARCEL 322345000014 IECT OWMER. )MARCH)ALL DISTURBED SOILS FTER STOP OF WORK EROSION T NOT BE LIMITED TO, Re,/'IW'NI`M3FI IS. IG SPOIL PILES MATH PRE MATTING,STRAW MULCH, Foe`AREAS SHALL TAKE -CHECKED REGULARLY 3 COMLETE.AREAS SHALL BE S REQUIRED, NORTH ALLOWED IF ANY SOIL IS ALL BE REMOVED BY THEE END RIICKIND OF MUD VWLL THEN SCALE 1"=50' IG OF THE VEHICLES TRES )OWNSLOPE OF MORE THAN 5 ON THE UPHILL SIDE OF TRENCHES. DISCHARGED IN A MANNER THAT WILL 0 10 20 30 40 50 'MS.DRAINAGE SYSTEMS OR SCALE:1 inch=50 feet JNOFF FROM THE PROJECT DURING -O THAT SEDIMENT-LADEN WATER E CONVEYANCE SYSTEM. Y ADJACENT TO THE SITE D OR SODDED UPON COW LETION FIGURE 2 RESPONSIBLE ENSURE THAT :D AREAS IS FROO NDED d TMAT ISHED, R FILTER FABRIC MUST BE SITE PLAN IN IS ESTABLISHED. 1/2 INCH MINIMUM DIAMETER STEEL ROD (STRAP)CLAMPED SECURELY TO PIPE CORRUGATED TIGHTLINE 4 INCH MINIMUM,6 INCH SUGGESTED 5�+z,..+;ta_.t.:,....�^::. :t:�:'!s-:::... :t,.•.:•."`=�'':Y i n.•a:.;. ,7.w:l�is.i:;+..'•lam}.�Y: i F :.;:w.�•. . l�r . a'4'/ TIGHTLINE ANCHORED WITH TWO, 3 FOOT REBAR LENGTHS OR BOLTS. FLARE END SECTION QUARRY SPALL OR ENERGY DISPERSION DEVICE ';,::�:` `;.i,..,:t^ �_ "'k:w �;<ls'; .,:...•„ GRASS-LINED SWALE SHOULD BE A MINIMUM ONE FOOT WIDE AT THE BOTTOM AND ONE FOOT DEEP WITH A MAXIMUM SLOPE OF 5 PERCENT. MINIMUM 4 FEET LEVEL SECTION GEOTEXTILE FABRIC Geotechnical Testing Laboratory Geotechnical Services 10011 e�e«g si.sw QWQC services P a i,WA 612,Z FIGURE 3 Testing Services Fe::(360)754-e848 Not to scale DRAINAGE DETAILS CROSS-SECTION A (NORTHEAST-SOUTHWEST) 140 . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . .... . . . .. .. . .. . .. .. . . .. . . .. . . .. .. .. . ... . ... . . .. .. . . .. .. .. .. . . .... .. 130 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... .. . . . . . .. .. . ... . . . .. .. . . . . .. .. lu ILL 120 . . .. . . . . . . ......... ....M . . . . .. . ... . .... .. .... .. .... .. . . . . .. .... .... .. ... . ...... . .. . .... . . ... . .. .. 110_ . . . .. . . . ... .... . . . . . . .. . . . . . . . . . . . . .. .. .. . . .. . . . . .. . . .. .. ....... . . . .. .. . . .. .. . . .. . . .. . ... .... .. . . .... . ... .. 100.. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. .. . . . . . .. . . . ..:. .. . .. . . . ... .. ..•. . .. . . . . .. .. . . ..•.. .. .. . . .. . . .. . ... . . .. .. Qs uj • 90 . . . . . . .. . . ..... . . .. . . .. . . . .. 0 . . . . .. . ... .. . . . . . . .. . . . . .. .. ..... ... . .. . . .. .. ....... .. . . . . . . .. ....... .... .... . .. ....... . .. . . .... . . .. . . 80 I.-.N. . . . . . . . . .. . . . . .. .. .. ** *' *''* '' *... .. .. *.,.:.:. *... .... *.*. .' *.O*C' ' * ' ' *,:.....*......... ..*.*. . .. ..:''**'016 . .. .. :. . . . . . . . . 70 .. . . . . . . . . . . . .... . .. . . . .. . . .. . . .. . . . . ... . .... . ... .. . . . . .... . . . . . . . . .. . . . . . . . . .. . . .. .. .. ... . .. . . .. . . .. . . 1"O" .. .. .. .. . ... . . .. 60 .. ...flPPRP?(.PROPOSEDj�cd.L. . . . .. . . .: ORTH:SHORERD 50 . . . .. .. . . .. . . ... . .. ..:' ' QIS . . .. . .. ..-. . .. .. ... . I... . ... . .. .I.. .. .. .... . . .. . . .. . . . . . . .. .. .. .. .. . 40 . . . . . . . . . . . . . . . .. .. .. . . . . . .. ... . .. .. .. . .. . .. . . . . ... ... .. .. ... .. . ... . .. . . ..30 . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . .. .... .. . . . . . . . . ... .QIS.. . . . . ... . . . .. . . .. .. ..... . .. . . .. . . .. .. . ... . . .. . . .. .. 20 . . ... . . . . . . . . . . . . . . . . .... .... .. . ... . . . . . . 11 . . . ...I . . . .. .. S. .. . .. . .. . . . . .... . . ... .. .. . . .. .. .. .. . . . . .. .. 10 0 0 150 100 150 1200 1250 1300 Geotechnical Testing Laboratory Geotechnical Services 10011 Blomberg St.SW FIGURE 4 Olympia,WA 98512 SCALE QA/QC Services Phone:(360)754-4612 V.50' CROSS—SECTIONS Testing Services Fax:(360)754-4848