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HomeMy WebLinkAboutGEO2009-00062 BLD2009-00627 - BLD Engineering / Geo-tech Reports - 8/6/2009 MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Planning Division P O Box 279, Shelton, WA 98584 111910 (360)427-9670 Geotechnical ReportReview Acceptance Letter August 25, 2009 DANIEL ROBINSON 4593 E STATE ROUTE 302 BELFAIR WA 98528 Case No.: GE02009-00062 Parcel No.: 122285002901 Proiect Description: GEO REVIEW FOR BLD2009-00627 The Geotechnical Report for DANIEL ROBINSON has been received and reviewed by the Planning Department. The report was prepared by Curtis Cushman dated 8/6/2009. 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 Allan Borden Land Use Planner Mason County Planning Department Comments: APPLICANT PAID FOR THE GEO REVIEW, THE REPORT WILL BE SUBMITTED IN A WEEK OR 2. 8/25/2009 Page 1 of 1 GE02009-00062 G EOTECHNICAL REPORT 4593 EAST STATE ROUTE 302 BELFAIR WASHINGTON RECEIVED ' AUG 1 1 2009 M CC D - PLANNING PREPARED FOR DAN ROBINSON BY GEOTECHNICAL TESTING LABORATORY OLYMPIA, WASHINGTON AUGUST 6, 2009 GEOTE" CHNICAL TESTING LABORATORY CONTACT INFORMATION PREPARER INFORMATION RECEIVED GTL PROJECT NUMBER: 09-0151 AUG 11 IUUS CONTACT: CURTIS D.CUSHMAN MCCD - PLANNING ADDRESS: 10011 BLOMBERG STREET SOUTHWEST OLYMPIA,WASHINGTON 98512 TELEPHONE: (360)754-4612 FACSIMILE: (360)754-4848 EMAIL ADDRESS: CCUSHMAN@GEOTECHNICALTESTINGLAB.COM CLIENT INFORMATION CLIENT: DAN ROBINSON TELEPHONE: (360)277-0546 BILLING ADDRESS: DAN ROBINSON P.O.Box 307 GRAPEVIEW,WA 98546 SITE ADDRESS: 4593 E STATE ROUTE 302 BELFAIR,WASHINGTON 98528 PARCEL: 122285002901 GPS LOCATION: N47°22'21.64"W122°48'46.92" 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 2 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOT ECHNICAL TESTING LABORATORY SCOPE OF UNDERSTANDING DAN ROBINSON P.O.Box 307 GRAPEVIEW,WASHINGTON 98546 RE: GEOTECHNICAL REPORT 4593 E STATE ROUTE 302 BELFAIR,WASHINGTON 98528 PARCEL 122285002901 N47°22121.6411 W122°48'46.92" AUGUST 6,2009 Dear Mr. Robinson: 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. Part of the following uses data from the previous on-site report of Harold Parks in 2001. For this study, an additional two samples were taken and submitted for laboratory testing (SL-1 & SL-2). 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 sampled ditch, road cuts, and elsewhere on the property. The underlying units are different from those at the building site. 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, GEOTECHNICA TESTING LABORATORY Wash f� �o �J^ Vijay Chaudhary,E.I.T Staff Engineer glneering Geologist 2439 sed G. ^117711 D E/"1 C U N MAN Curtis D. Cushman,L.G.,L.E.G. Senior Engineering Geologist 09-0151 10011 Bloomberg Street SW, Olympia,WA 98512 3 Phone#: (360)754-4612 Fax#: (360)754-4848 GEO°i`ECHNicAL T TING LABORATORY 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 11 SUBSURFACE CONDITIONS 12 SLOPE STABILITY AND ANALYSIS 12 SLOPE MODEL 13 RECOMMENDATIONS FOR BUILDING SETBACK 15 VEGETATIVE MANAGEMENT 15 RECOMMENDATIONS FOR EROSION CONTROL 16 SEPTIC IMPACT 16 RECOMMENDATIONS FOR SITE DRAINAGE 16 EARTHWORK 17 RECOMMENDATIONS FOR SITE PREPARATION 17 RECOMMENDATIONS FOR STRUCTURAL FILL 17 RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL 18 RECOMMENDATIONS FOR CUT AND FILL SLOPES 18 RECOMMENDATIONS FOR FOUNDATION SUPPORT 18 SEISMIC LIQUEFACTION HAZARD 19 GEOSEISMIC SETTING 19 LATERAL EARTH PRESSURES 19 RECOMMENDATIONS FOR FLOOR SLAB SUPPORT 20 RECOMMENDATIONS FOR RETAINING WALLS 20 MASON COUNTY PRESCRIBED WALL DESIGN 22 RECOMMENDATIONS FOR RETAINING WALL ALTERNATIVES 24 CONCLUSIONS AND RECOMMENDATIONS 24 GENERAL 24 REPORT LIMITATIONS AND GUIDELINES FOR USE 24 CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS 24 READ THESE PROVISIONS CLOSELY 25 REFERENCES 26 APPENDIX 28 LABORATORY ANALYSIS 29 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 4 Phone#: (360)754-4612 Fax#: (360) 754-4848 GEOTECHNIC L TESTING LABORATORY SIEVE ANALYSIS 29 SHEAR @ SL-2 31 FIGURE 1 32 FIGURE 2 SITE PLAN Attached FIGURE 3 EROSION CONTROL NOTES Attached FIGURE 4 CROSS-SECTION Attached 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 5 Phone#: (360)754-4612 Fax#: (360)754-4848 GE,OTECHNICAL TESTING LABORATORY INTRODUCTION This report summarizes the results of our geotechnical consulting services for the proposed residence. The building will be constructed on a previously cleared site. The report has been commissioned by Dan Robinson. The site is a roughly rectangular lot with the long sides trending east-west. It is located on the end of a ridge on the west side of Key Peninsula with North Bay to the west and a stream to the south and east. The site opens to a ridgeline to the north. The site overlooks North Bay and is across from Allyn, Washington. The site is approximately 10 miles by road south of Belfair, Washington, and is accessed from an existing driveway from SR 302. The location of the site is shown relative to the surrounding area on the Vicinity Map, Figure 1 (at the end of this report). lyn I r_-r T. V 3 '.. �Yy ��I�cer a.ial •. `5can erasew Cde) _ .,narocavr�r • Our understanding of the project is based on our discussions with the client. We understand that the parcel is to be developed by building a single family residence with attached garage near the center of the parcel. In general, further grading will limited to the development of the new 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. 09-01 5 1 10011 Bloomberg Street SW, Olympia, WA 98512 6 Phone#: (360)754-4612 Fax#: (360)754-4848 GiL0T ctiNicAL THING LABORATORY 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). The steep slope measured on the west side dropping down to SR 302 exceeds 40% and is within 300' of the building site. Therefore, Mason County requires that a geotechnical report be prepared in accordance with the Critical Areas Ordinance. 17.01.100E5 (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 spotty residential development with much of the shoreline of Hood Canal having residences on them. There are also scattered individual residences and nearby clusters of moderate development. c Facing West The site was inspected in 2001 by the late Hal Parks, and revisited on July 23, 2009 by Curtis D. Cushman. The purpose of a site visit is to physically observe the property and adjacent properties in order to identify any recognized geologic conditions. Soil samples were taken from a trench on-site (SL-1) and the road cut below the building site (SL-2).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 grass-covered,with the grass continuing to the west away from the building site. The remaining slopes to all sides are heavily vegetated with juvenile to mature evergreens,maples,and indigenous shrubs and ferns. The building site is situated on a flat graded cut at the end of the ridge. The building site slopes down south and east to the drainage and west to the water of North Bay. The overall property elevation ranges from 40 feet to 100 feet. 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 7 Phone#: (360)754-4612 Fax#: (360) 754-4848 V EoTmINICAL T TiNG pmTopv The building site is relatively flat. The road leading to it corkscrews around the ridge tip in cuts exposing the geology. No groundwater was observed on property or on this road. The water table is assumed to be at or near the level of the Sound. No erosion was seen on site. No surface water or ponding was observed at the building site. Some minor slumping and sloughing was observed along the road in the cut. 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- site to the east and south are straight and vertical. In general, creep was not seen. There is no upland water body of any sort above the property. There are no nearby wetlands. No water was present in the adjoining stream at the time of the 2009 site visit. The steepest slopes are those above State Route 302 on the west(approximately 50%), and a shorter section along the east side that is locally somewhat steeper. The southern end slopes at over 30%, with the top 10 feet or so formed by shoved-out fill material. The building location is essentially flat. The landslide hazard area and appropriate setbacks are shown on Figure 2. The site is served by a well on site. The site has no septic due to its being served by local sewage 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 locations(SL-1)and(SL-2)are 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. 09-0151 10011 Bloomberg Street SW, Olympia, WA 98512 8 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING 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, earthflows, slumps and rockfalls (see figure F.100). b.Areas with artificial oversteepened or unengineered slopes, i.e. cuts orfills. 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 artificial 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. 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 9 Phone#: (360) 754-4612 Fax#: (360) 754-4848 Gr6oTtamicAL LISTING 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 15%or steeper: a.Alderwood gravelly sandy loam ("Ac"and"Ad') b. Cloquallum silt loam ("Cd') c. Harstine gravelly sandy loam ("Hb') d. Kitsap silt loam ("Kc') The 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 have been removed. They remain in place on the adjacent slopes. Where seen just above the ditch cut in the property, the soil is 8" to 12" thick and grades quite suddenly into its lower horizons. The soil is therefore shallow with respect to the underlying glacial materials(see below). No soils other than those already cleared will be disturbed. 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 10 Phone#: (360) 7544612 Fax#: (360) 754-4848 GE®"i'ECHNICAL TESTING LABORATORY The Soil Survey of Mason County, USDA Soil Conservation Service (1960) has mapped the site soil as the following: 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 Alderwood gravelly sandy loams. This soil is more variable than Everett gravelly sandy loam, 5 to 15 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. 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 The description of the site materials was originally described in the Geologic Conditions in the 2001 report. It was taken from the Coastal Zone Atlas, Volume 9, Mason County. This is still the best resource for the area, although the nomenclature is different: Qvt is now Qgt, and the underlying Qva is now Qga. Sample descriptions will be found in the appendix. The units are described in the 2001 text. There are no recorded landslides in the North Bay area, and none seen on CZAW 12ith which includes the property. SUBSURFACE EXPLORATIONS Subsurface conditions at the site were evaluated by observing and logging the extensive outcroppings of materials along the entry road,probing, reviewing available well logs, and sampling by shovel. As this is an already graded site,the building location appears to correspond to the described Qgt. Sample SL-1 was collected as a grab composite taken along the sewage ditch. SL-2 was likewise sampled on the lower road above the gate. The samples were sealed in Ziploc bags, labeled, and transported to our soils laboratory. The soil gradations were 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 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 11 Phone#: (360)754-4612 Fax#: (360)754-4848 SUBSURFACE CONDITIONS Beneath the Everett soils the Qgt, a Till, is approximately 8 to 10 feet thick. It is underlain by the sandier Outwash, Qga, which comprises the rest of the column down to the State Route. The Till is excellent for the proposed construction. The gradation of the representative soil sample taken at SL-1 (the construction site) is included in the appendix. This sample was well-graded gravel with sand (G99. All the observed exposed soils and glacial materials are sands with varying amounts of gravel with the fines(-#200)less than 10%. 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 or human activity. No evidence of significant recent erosion was observed onsite at the time of our investigations. However, weathering and associated surficial erosion is seen confined to the upper weathered or disturbed zone, which has a lower strength. Creep was rare and very weak. 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. Further grading in the building portion of the site should be conducted in accordance with geotechnical recommendations provided herein. 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 2007 program (version 7.13) 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 in two layers, Qgt overlying Qga. The parameters, for the upper layer(Qgt)was described as per the previous report and the lower layer(Qga)was obtained from the direct shear test run on the grab sample (SL-2). The parameters for both layers are depicted in slope model itself. As water was seen nowhere on site, a perched ground water table was not modeled 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 12 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY 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 amic A 2.142 1.305 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. SLOPE MODEL SLOPE MODEL A STATIC FoS: 2.142 jj 130 • 2.142 ' •• 120 Name: Qgt 110 Unit Weight: 138 pcf 100 Cohesion: 150 psf r I � o Phi: 39 • 90 iv ai 80 Name: Qga w Unit Weight: 128 pcf 70 Cohesion: 110 psf 6o Phi: 40 50 I 40 0 =- 60 80 120 140 160 180 200 0 240 Distance 09-0151 10011 Bloomberg Street SW, Olympia,WA 98512 13 Phone#: (360)754-4612 Fax#: (360)754-4848 GIEOTECHNICAL TMiNG LABORATORY SLOPE MODEL A DYNAMIC FoS: 1.305 • • • . t305 • 130 • • • . • • • • 120 �• �• • . • • • • • •Name: Qgt • 110 • Unit Weight: 138 pcf • 100 ¢f • o Phi: 39 • 0 90 • cd aa) so Name: Qga W Unit Weight: 128 pcf �o Cohesion: 110 psf 6o Phi: 40 50 40 0 __ 100 120 140 160 180 200 240 Distance 09-0151 10011 Bloomberg Street SW, Olympia, WA 98512 14 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GE;0"` ETHNICAL TESTING LABORATORY 17.01.100E5 (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. Please see below and the Earthwork section of this report. 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 are natural processes that affect slope areas. resultant surficial sloughing and shallow landsliding Setback 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. The buffers and setbacks from the landslide hazard areas are shown on the figure 2(site plan). 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. There is off-site sewer. ➢ Preserve existing vegetation. ➢ The setbacks and buffers are shown in the site plan. 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. VEGETATIVE MANAGEMENT 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. 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. 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. A revegetation plan should be in place before the end of construction. The choice of native vegetation and the planting locations should be provided by a professional horticulturist 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. 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 15 Phone#: (360)754-4612 Fax#: (360)754-4848 GROTEC NIC.A L TESTING LABORATORY 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. Implementation of any or all of these recommendations is the sole responsibility of the owner. 17.01.100ES (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 rare creep of very limited extent. 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. Further 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 hill slopes 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. 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. 17.01.100ES (10) An analysis of both on-site and off-site impacts of the proposed development. The proposed development will have no adverse impact on the landslide hazard areas and vice-versa. SEPTIC IMPACT No septic system is on site. 17.01.100ES (11) -- Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Please refer to the Building Setback,Vegetative Management,Figure 2 and Figure 3 for this section. 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 09-0151 10011 Bloomberg Street SW, Olympia, WA 98512 16 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY 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 (12) -- Recommendations for the preparation of structural mitigation or details of other proposed mitigation. No structural mitigation is predicted for this project. 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, this has been done. Some deeper stripping locally should be anticipated if further grading is required,. No deeper excavation is expected at the building site except along the proposed foundation. 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 and compacted to the density requirements described in the"Structural Fill"section of this report. If structural fill is needed, we recommend that a member of our staff evaluate the exposed subgrade conditions 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. 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 17 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY 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. 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. 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. 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 2,500 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. 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 18 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY 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. 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 very low or very low liquefaction potential. (The actual site on the map is covered by a Route 302 shield.) 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 or D. Site class C is a very dense soil or soft rock, class D is a stiff soil(IBC). Based on our review of the exposed soils, we conclude that the site is not 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. 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) 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) 39 degrees • Ko(at rest earth pressure coefficient) 0.37 • Ka(active earth pressure coefficient) 0.25 • Kp(passive earth pressure coefficient) 4.00 • y(soil unit weight) 138 pcf 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 19 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY 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:1V 25% 44 pcf 2H:l V 50% 53 pcf 1H:1V 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. 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 20 Phone#: (360)754-4612 Fax#: (360)754-4848 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. 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 21 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY MASON COUNTY PRESCRIBED WALL DESIGN MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Mason Caun-y Bldg. 111,428 West Cedar Street PO Box -5e. S-ne ton.WA 98584 w.vw.aD.mason.l us f38D;1427-E+87D Belfar(36D; 7_-448- Eiria :MC.'482-`_2-52 UPLAND CONCRETE RETAINING WALL Prescriptive Design & Installation Standard DESIGN STANDARDS DO NOT APPLY TO SHORELINE EROSION CONTROL BULK1-IEAM F- ! r-,� I Slope less .�Ian or equal to 1:1 r s- BARS V-SARS I 1 1 1 S-SARS 1 1 1 I MWIDE FLOOD I I 1 I PWJ9F C{ATINr, 1 1 1 I • .d - = 1 I Vl- 2• 1 I 1 I BARS � ��—, � I 1 � I I 1 I I � AT I?' O_C. a I 1 1 1 I 1 1 I 1 -1--t--�--t-—I—-r-I—-1—- n —F ler'at GROUND rlc I I 1 j I 1 1 1 BARS SURFACE Gi " a'Fe f-r3ted-1 e - - - - - - --it-A- 12' rein. — � d3ylgnLeJ an I 1 I 1 I I 1 1 1 _ 6a ppmk*c cc31-on. I I I I I I 1 I 1 Grace 1c rco �I 1 1 1 I I 1 I I FoCtIngs V.. 61'al be _�.+T '=HEAR KEY. g_RaAs placed on LGE 2K6 rrm "tiv wl KNOCKOJT ELEVATION SAII 9 X NOTE: SECTu_r, SParlNr,OF S-SARS ISAPPRRxIMATE. USE TABULAR NUMBER OF B&R3 AhO SPACE EvENLY wr 2"COVER a- H B T wC_i'�NC E..0.RS 3TH3 BB- b P.EINFOP.CEMENT FT Fr-IN H N-D3'.T'r SZE '•-A-14o 'i1-SAJAS 2-BAPS 612E .PALING LEN(3r." x 81ZE sr+..c.ti,% LLa PER FOOT 3-6 '7 7.25 3.c ']' E-L' z i' •7' 21-21 3 9' -_ m3 13 13.30 112' 11T 71L• — 1:S 'T ='•'3- 1 3,9' 12' 13.1 r1C 10 0.3s VS T aw — 1:S a'-9' 1 B 3-8' tY 19.8 Era 12 OA7 Ste' 9' 9'-8' E--]' 5.•9' S' =1•9' 1: 3-9' 12• 2AA 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 22 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY Prescriptive Concrete Retaining Wall DEWN STANDARDS Height.,Maximum Eight Feet Upland concrete retaining walls installed :n accordance with the prescriptive design shown on the reverse side need not be designed by an engineer unless the Mason County Building Cept. determines special conditions exist_ Any retaining wall exceeding eight feet in height or varying from the prescr pti-;e design requires an engineered design. Location of Retaining Waft Retaining wal•s must only be placed against stable slopes, consisting of firm, undisturbed soi. Drairage must be provided as shown with a 4'perforated drain pipe or 2`weep hoes spaced not less than 12 feet on center. No surcharge oad,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 wa I unless an engineered design is ,.repared for the additiona load. Ground Surface Above Retaining Wall The ground surface above the retaining wall shall be ess than or equa 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 footing 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 waf. The drainage materials n•ust 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 pGpe,with at least a four-=rich diameter,shall be installed within the drainage materials. The drain pipe must dm n to a point of discharge,approved by Mason County. Inspections Prior to the a acement of concrete.the bui±der must schedule an inspection of the formwork and reinforcement placement for the retain ng wall footing. During the first inspection,the inspector will verty the soil condition,footing dimensions,footng reinforcement.and footing placement as wel as the provisions for drainage. At the next inspection,the inspector shali verity the wall d-mens�ons and reinforcement prior to the wall pour. A final inspection must be performed once al work is complete. To schedule an inspection ca.I the Mason County 24-hour recorded inspection request ine at(360)427- 7262. Inspections can also be requested online at:www.co.mason.wa.us or by fax at(360)427-779& When requesting an inspection please provide the following information 11 Name on oennit 2)type of inspection 3)Permit number 41 Site Address 51)Type of permit 6) Date inspection requested and 71 Name and phone number of caller. 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 23 Phone#: (360)754-4612 Fax#: (360)754-4848 GEoTr6 mcAL TnTT`ING LABORATORY 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. 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. REPORT LINIITATIONS AND GUIDELINES FOR USE We have prepared this report for the exclusive use of Dan Robinson and his 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. 09-0151 10011 Bloomberg Street SW,Olympia,WA 98512 24 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY 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. 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 25 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. Pahner, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004), The Site Class Map of Mason County, Washington,published by Washington State Department of Natural Resources. Rogers, A. M., Walsh, T. J., Kockelman, W. J., and Priest, G. R. (1996), Map showing known or suspected faults with quaternary displacement in the Pacific Northwest, published by U.S. Geological Survey OFR 91-441-0, Plate 1, scale 1:2,000,000. Smith, Carson (1977), Relative Slope Stability of the Southern Hood Canal Area, Washington, prepared in cooperation with the Washington Department of Natural Resources Division of Geology and Earth Resources; and, Department of the Interior United States Geological Survey. 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),2006International Building Code,published by International Code Council,Inc. 09-0151 10011 Bloomberg Street SW, Olympia, WA 98512 26 Phone#: (360)754-4612 Fax#: (360)754-4848 GaoTwKNICAL 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`h 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.html) Slope Stabilization Erosion Control Using Vegetation A Manual of Practice for Coastal Bluff (http://www.ecy.wa.govlbiblio/9330.html) Vegetation Management Guide for Puget Sound Bluff Property Owners (http://www.ecy.wa.gov/biblio/9331.html) United States Department of Agriculture Natural Resource Conservation Service (http://soildatamart.nres.usda.gov) Washington Administrative Code (http://apps.leg.wa.gov/wac/) Washington Department of Ecology (http://apps.ecy.wa.gov/welllog) (https:Hfortress.wa.gov/ecy/coastalatlas/viewer.htm) 09-01 5 1 10011 Bloomberg Street SW,Olympia,WA 98512 27 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY APPENDIX 09-01 5 1 10011 Bloomberg Street SW,Olympia,WA 98512 28 Phone#: (360)754-4612 Fax#: (360)754-4848 GEoTECHNICAL TESTING LABORATORY LABORATORY ANALYSIS SIEVE ANALYSIS U.S.Standard Siew Opening in Inches U.S.Standard Hydromotaf R-asults 100% w A-A- 0% 905fi -- ----------------T---------------------------------------------------------------------- ----------------------- 10% 80% ----------------------4-- ------------------T-------------------------------------------------- --------------------------------------- 20% 70% ----------------------4-------- ----------- --------------------- ---------------------- ----------------------- 30% 60% ---------------- -T----------------------- ------------- 40 -------------- --------------------- % > 50% ------------------------------------------ -- ----------------- -------------------- --------------------- --------------------- 50% w40% ---------------------I---------------------I-------- ----------- -------------------- ------------------------------------------- 609.6 M C: CLI I M 30% ---------------------A---------------------I-------------- -----F--------------------i-------------------------------- ---------- 705-6 Ly PP 20% ---------------------I-----------i------I--------------------- ---- -------------i----------------------------- ------ 10% --------------------- ---------------------t--------------------- --------------- --I------------------------------------------- 9()% 0% 100% M 10 1 0.1 0.01 0.001 Grain Size in M 11 lim eters Cobbles Gallls Sands silts Claw Coars- I Fins CLu- Fin. Date: 0728,109 D..0= 0.13 Classification %Gravel Sample io: 409 D34= 2.03 GIV,Well-graded Gravel with Sand 56.73% Sample ID: On Site Native D,,= 1438 Specifications %Sand Source: SL-1 C,= 1.61 No Specs 39.29% Project: Robinson C'- 80.95 %'Moisturi=DrV 0! %Silt&-Clay Client: Dan Robinson Liquid Limit= 0.00 but Ratio- 3.98% C-136 Plastic Limit= 0.00 Fineness Modulus Sample Meets Specs Depth: -1 Plasticitv Index-- 0.00 5.88 Yea Coarse Actual ::Interpolated flues Actual Unterpolated Section Cumulative Cumulative Section Cumulative::Cumulative ................ ....... ................. Percent Percent Percent Percent US Metric Passing Panin- I Max Min us Metric Passing Passing Ma: 6.001, 130.00 100.0% 4.750 43.3% 43.3% 4.00" 100.00 100.0% 100.0% ;4 2.360 33.0% 315.0% 3.00" 75.00 75.6% 75.6% 410 2.000 29.6% 29.6% 2.50" 63.00 73.2% 916 1.180 26-0% 2.00" 50.00 70.7% 020 0.850 24.5% 24.5% 1.75" 45.00 69.7% 030 0.600 20.3% 1.50" 37.50 69.2% "0 0.425 17.4% 1-25" 31.50 67.0% i 7,50 0.300 15.3% E 15.3% 1.00" 1 25.00 65.7% -t60 0.250 13.2% WS" I 22.40 65.2% ;=so 0.180 10.1% 3/4" 19.00 64-5% 64.5% zkloo 0.150 8.9% 8-8% 5/8., 16.00 61.6% 4140 0.106 6.0% 1-2 12.50 58.2% 58.2% 1 ;i470 0.090 4.9% 3 S" 9.50 E 54-5% 54.5% -d200 0.075 i 4.0% 4.0% 6.30 46.9% 4270 0.053 Copyright Spew,Engineering&Technical Service:PS,1396-2004 09-0151 10011 Bloomberg Street SW, Olympia, WA 98512 29 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTEC'HNICAL TESTING LABORATORY U.S.Standard Sieve Opening inlnches U.S.StandardSieveNumbers Hvdrometef Result 100% 0% 90% ---------------------------- - --; ---- i i i i i 80% i -------------------------------------------- -...___ ------ --------------------- .___.._____ _-------t--------------------_ 2�'�r'n _ 1 1! 70°! 1 - --- - - - - -- ----- - --- - - ----- -- --- -;• -- - - ----------- ... 30 m I 60% -- - -- -- - -- - - ----- - - - ; 40% EM 40% --------------------i--------------i------i----------------- -4--------------!--- i---------------------f------- ---------- 60% c 1 A30% --------------------I----------------------1--------------------- -------------`-- - i---------------------+--------=--- 7,0% V I I 12 2096 -- - -- - --i-- - -- -- - t---------------------F--- ---------------i---------------------+--------------- - SO% I I 10% --------------------i---------------------+---------------------F-------- ---------- ---------------------+--------r------------ 9Cj% I I ' 0% 100% 100 10 1 0.1 0.01 0.001 Grain Size in Millimeters Cobbles Grs�els Sands Silts Clays Coarse Fine I Coarse llaclium Finn Date: 07 28 09 D. = 0.38 Classification °'o Gravel Sample=: 409 Dsa= 0.98 SP,Poorly graded Sand with Gravel 19.64% Sample ID: On Site Native Dge= 2.77 Specifications 'm Sand Source: SL-2 Ct= 0.90 No Specs 78.84'm Project: Robinson C,- 7.29 %Moisturi=DID-0" 1.Silt Clav Client: Dan Robinson Liquid Limit= 0.00 )ust Ratio= 1.521% aSTM=: C-136 Plastic Limit= 0.00 Fineness Modulus Sample Meets Specs Depth: Surface Plasticity Index-- 0.00 4.04 Yes Coarse Actual T te2p0 te6 Fines Actual :Interpolated Section Cumulative:Cumulative Section Cumulative Cumulative Siei=d..S a................ Percent Percent ....... ......,...... ....... ....... ......5ieve...size.......... ...... Percent Percent ,.......Sj ee- .....,.......Sp .......... L'S Metric PassingPassing Max Min U8 Metric ?assin; ; Passing -lax llin 6. " 150.00 10C.0% :#4 4.750 80.4% 80.4"a 4.00" 100.00 100.0% 1 4 1 2.360 53.8% 55.8% 3.00" 75.00 100.0% 410 1 2.000 49.7% '•. 2.50" € 63.00 100.0% € ;�16 1 1.180 35.8% 35.8% 2_QO" 50.00 1 100.0'�i20 0.850 26S°: 1.75" € 45.00 € 100.0°A 430 € 0.600 19.4% 19.4% 1.50" € 37.50 € 1 100.0°A € 440 0.425 11.9% 1.25" € 3150 € 1 100.0°A T50 1 0.300 1 6.6% 6.6% 1.00" 1 25.00 1 100.0°A =60 0.250 1 5.4% 718" € 22.40 € 100.0% --80 € 0.180 € 1 3.7% 34" 1 19.00 100.0% 100.0% 0100 1 0.150 3.0'A 1 3.05G 1 16.00 1 1 99.2% 1 0140 1 0.106 1 1 2.1% 1 12" 1 12.50 1 98-2% 1 98.25E 1 ;0170 1 0.090 1.8% € 3 8" 1 9.50 1 95.55E € 95.5% i :4200 1 0.075 1 1.5% 1.5% 1 14" 1 6.30 1 853% 4270 1 0.053 1 Copyright:Spear,Engineering 6 Technical Service^.PS,1336.2004 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 30 Phone#: (360)754-4612 Fax#: (360) 754-4848 SHEAR @ SL-2 Peak Shear Stress vs. Normal Stress 2500 i Shear=40° 2000 a ffi b 1500 m r rN Y w • d 1000 .10 1r4ton 500 1;2ton �-1 ton Cohesion =110 psf 0 500 1000 1500 2000 2500 KIK Normal Stress(psfl 09-0151 10011 Bloomberg Street SW, Olympia, WA 98512 31 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY FIGURE 1 _ High , -- f'J % � ''• / •_!'�, r is� f/��;,•.: •SIT of I I + 1 i C ��� -:�� — t To, , U Rl / P•'1 ., 1 � � locks �` - �!'Igo f •� ��)(/� f - - � I a -,' .0 OI 3�h0 J. Rocky Pol •�' ��,", flocks ROCKY I .. I 5N. ©2002 DeLorme.9-0 TopoOuede U.Oele copyrlflht of content owner. 09-0151 10011 Bloomberg Street SW,Olympia, WA 98512 32 Phone#: (360) 754-4612 Fax#: (360) 754-4848 FILTER FABRIC MATERIAL SO'WIDE ROLLS SITE PLAN WAS PROVIDED BY THE CLIENT. USE STC APLES OR VVIRE RIG TO ATTACH G e o to c h nic al FABR TO HARE 771 .1AGALJOEWIRECONTOURS ARE BASED ON MASON COUNTY GIS AND OUR SITE RECONNAISSANCE RIC OR EQUIVALENT CONDUCTED BY CURTIS D CUSHMAN ON JULY 23,2". Testing z SURFACE A' Laboratory K B MAX Qj� 2"Xf WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER BETTER OR EQUAL ALTERNATE: MATERIAL IN rXIZ'TRENCH STEEL FENCE POSTS FILTER FABRIC HT• TX2'XI4 GAUGE V WARE FABRIC OR EQUNALENT (� v 2, / GROUND SURFACE SP PROVIDE 31P-1/?WASHED (A GRAVEL SACKFILL IN TRENCH 77 O Q) I AND ON BOTH SIDES OF FILTER FENCE FABRIC ON THE SURFACE 8- AT4 WOW PMT POSTS 1 Geo/t�echnical Services FILTER FABRIC PENCE NOTES: QA/ C Services I \ \ `,1 1 \ // 1 A FILTER FABRIC SHALL BE PURCHASED IN CONTINUOUS ROLL CUT TO TCC ` 1 \ THE LENGTH OF THE BARRIER TO AVOID USE OF JOINTS.WHEN JOINTS Testing Services ARE NECESSARY,FILTER CLOTH SHALL BE SPLICED TOGETHER ONLY AT A SUPPORT POST VATH A MINIMUM 04NCH OVERLAP AND SECURELY FASTENED AT BOTH ENDS TO THE POST. 2.POSTS SHALL BE SPACED A MAXIMUM OF B FEET APART AND DRIVEN SECURELY INTO THE GROUND(MINIMUM Of 301NCHES). 3.A TRENCH SHALL BE EXCJk TED APPROXIMATELY 8 INCHES WOE AND 12 10011 Blomberg St.SW ALONG DEEP ALO THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER. Olympia,WA 98512 0.WEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH LkM, \ , SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE Phone:(360)754-4612 OF THE POSTS USING HEAVY-0UTY WARE STAPLES AT LEAST I INCH LONG,TIE VARES OR HOG RINGS.THE WIRE SHALL EXTEND INTO THE Fax:(360)754-4848 TRENCH A NCHES ABOVELTHE ORIGINAL GROUND SURFACEUM OF 4 INCHES AND SHALL NOT EXTEND MORETHAN30\\ 5.THE STANDARD STRENGTH FILTER FABRIC SHALL BE STAPLED OR WIRED Date: 08/05/2009 \ TO TIE FENCE AND 20INCHES OF FABRIC SHALL BE EXTENDED INTO THE TRENCH.THE FABRIC SHALL NOT EXTEND MORE THAN38Designed by:CLIENT INCHES ABOVE THE ORIGINAL GROUND SURFACE.FILTER FABRIC SHALLO 4 ) GT BE STAPLED TO THE EXISTIG TREES. Drawn by: VC 8.VVHEN EXTRASTREGTH FILTER FABRIC AND CLOSER POST SPACING IS Checked by: CDC USED,THE VANE MESH SUPPORT FENCE MAP BE ELIMINATED,IN SUCH O ACASE,THE FILTER FABRIC IS STAPLED OR VWRED DIRECTLY O THE Dwg#:08-05-09-013 POSTS IIWTH ALL OTHER ROVISIONS OR ABOVE NOTES APPLYING. T.FILTER FABRIC FENCES SHALL NOT BE REMOVED BEFORE THE UPSLOPE \\ OAREAHAS BEEN PERMANENTLY STABILIZED. 3' SETBAC 2 B.FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH \ RAINFALL AND AT LEAST DAILY DURING PROLONGED RAINFALL.ANY REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY. 1GEIIERAL EROSION CONTROL NOTES: 1. EROSION CONTROL MEASURES SHALL BE N PLACE PRIOR TO THE \ \ =479.711 6HALL NSPECT ANND APPROVE THE INSTTRUCTION.THE ALATION JECT OINEER AND THE COUNTY \ ` \ � EROSION CONTROL MEASURES PRIOR O BEGINNING CONSTRUCTION. �' 2.EROSION CONTROL MEASURES ARE GT LIMITED TO THE ITEMS \ \ ON THIS PLAN.THE CONTRACTOR IS RESPONSIBLE FOR THE INSTALLATION AND MAINTAINANCE OF ALL EROSION CONTROL MEASURES. NO SILTATION OF EXISTING OR PROPOSED DRAINAGE FACILITIES \ \ \ � SHALL BE ALLOWED CARE SHALL BE TAKEN To PREVENT MIGRATION PROJECT NAME: \ \ \ \ OF SILTS TO OFF SITE PROPERTIES. \ 3 THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL EROSION_ ROBINSON RESIDENCE SURES AND MAKE ANY CESSAII REPAIRS OR A TO THE ERNTROL OSION ON CONTROL MEAS ESE THE CONTRACTOR SHALLPTROVIDE 4593 E STATE ROUTE 302 SSARY BY THADDITIONAL COUNTY NISPECTORAND�ORTHEES AS ROJEC ENGINEER.FMAINED AILURE BELFAIR, WASHINGTON O COMPLY VITH ALL LOCAL AND STATE EROSION CONTROL \ \ \ RECMREMENTS MAY RESULT IN OVAL PENALTIES BEING LEVIED PARCEL 122285002901 \\ \ \\ \ AGAINST THE CONTRACTOR AND/OR PROJECT OWNER. \ \ \ A.OURNG THE WET SEASON(NOVEMBER TO MARCH)ALL DISTURBED SOILS \ \ SHALL IE STABILIZED WITHIN AB HORS AFTER STOP OF WORK EROSION \ \ CONTROL MEASURES SHALL INCLUDE,BUT NOT BE LIMITED TO, \ COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WITH ReVlsims: \ \ \ PLASTIC SHEETING STRAW MATTING,JUTE MATTING,STRAW MULCH, \ \ \ \ \ OR WOOD CHIPS.SEEDING OF THE DISTURBED AREAS SHALL TAKE PLACEM AS WEATHER PERTS. 5.ALL SEEDED OR SODDED AREAS SHALL BE CHECKED REGULARLY TO MAKE SE VEGETATIVE COVERAGE IS COMLETE.AREAS SHALL BE \ \ REPAIRED,RESEEDED,AND FERTILIZED AS REQUIRED. OF THAT DAY.ANY FURTHER TRACKING OF \ \\ \ \\ S IL IS TRACKED ONTTRACKING OF O COUNTY STREET,T SHALL BT 13E E REMOVED BYD.IF ANY OTHE END \ \\ \ \\ ___—————— WILL BE PRE NENTEDING fl SNEEPINC OR WASHING OF THE VEH COLES TIR�N \ \ \ ES BEFORE DRIVING ONACOUNTY STREET. \ T.NO INDITE THAN WO LF OF TRENCH ON A DDWNSLOPE OF MORE THAN 5 A PERCENT SHALL BE OPENED AT ONE TIME. EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OF TRENCHES. \ S,TRENCH DEWNTERING DEVICES SHALL BE DISCHARGED IN A MANNER THAT VALL \ \ NOTADVERSELY AFFECT FLOVANG STREAMS, \ EAMS.DRAINAGE SYSTEMS OR OFFSITE PROPERTIES. C^ 10.ALLSTORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJECT DURING SCALE:1Inch=$0 feet CONSTRUCTION SHALL BE PROTECTED SO THAT SEDIMENT-LADEN WATER �\ WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM. \ 11.ALLOFF-S TIE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE _ -- HALL ALL PROTEGEE SKIFROLL E SEED G U R E 2 72 ALL d3TURBED AREAS 9/ALL BE SEEDED OR SODDED IWON COMPLETION OF WORK THE CONTRACTOR SHALL BE RESPONSIBLE TO ENSURE THAT COMPLETE COVERAGE OF THE DISTURBED AREAS IS PRONGED S THAT ORQVTH OF THE VEGETATION IS ESTABLISHED. ' 13.NOTCH BASINS SHALL TRAP SEDIMENT OR FILTER ESTABLISHEDFABRIC MUST BE SITE PLAN ■j PLACED UN IS DER ORATE UNTIL VEGETATION . ■ 1/2 INCH MINIMUM DIAMETER STEEL ROD (STRAP)CLAMPED SECURELY TO PIPE CORRUGATED TIGHTLINE 4 INCH R L i/yi4, M MINIMUM,6 INCH SUGGESTED gC/NG FFT ,.: •Ci`,yr..: .'r�.y'. -- 4..ter;`=R'.�}c�..:'.r`.�� ;.:�!. - i..':..'���:, ^•��:7tFa 'a�\` yi....^'�j"'y�.'•a�\'.' .:'Sr aX.�r4�::... h:1�:i:,i ti•i'Faye:fl.v ic" .:�:.._.. .� a t' TIGHTLINE ANCHORED WITH TWO, 3 FOOT REBAR LENGTHS OR BOLTS. C,y FLARE END SECTION QUARRY SPALL � OR ENERGY ,. • rs -;..... .::_; : .:,-: :�,. . DISPERSION DEVICE 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 Bbmbwg 31.3W FIGURE 3 QA/QC Services ��p�'WA 99512 P-:(36 60))754 44612 DRAINAGE DETAILS Testing Services Fex:(380)754-0848 Not to scale CROSS-SECTION A (NORTHWEST-SOUTHEAST) 0\ 120.. . . . . . . . . .. .... . . . .. . . . . . . . . . . . . . . . . . . .. ... .. 110........................ ----------- .......... ................................................................. 100 . .. . .. . .. .. . . .. . .. .. .. . . . . .. . ... .. .. .. . . . . .. ........ .. 90 Qgt—---------------- .... .. . . . .. .... . . . .. . ... ... . .. ... . .. . . . . .. .. .... ... .. .. . .. . ... 80 . . ... . .. . ... . . .. .. . . .. . . . . . .. . . . . . . .. . . .. .I . . .. .. . ... .. .... .. . ... . . .. 70 Qga . . .. .. . . . . .. . . .. . . .... . . . .. .... .. .. .. . . . . I . . . .. .. . . CFNT 60 ............................................ .. .......................................................................................................... 50 �Qg . . .I . T 40 0 150 1100 150 200 1250 1�300 Geotechnical Testing Laboratory Geotechnical Services 10011 Blomberg St.SW FIGURE 4 Olympia,WA 98512 SCALE QA/QC Services Phone:(360)754-4612 1"=50' CROSS-SECTIONS Testing Services Fax:(360)7544848 i � Slope Stability Investigation Lot 1 of SS 2633 Mason County, Washington Prepared for Dan Robinson Grapeview, Washington by Geotechnical Testing Lab Olympia, Washington January 25, 2000 W W W W W W W W W W W W W W W W W W W W W s�xi NN 'CJ y w O O U O O tWn O Vai O U p N to t�A N !n mama m 8$ $888888888888888888� ;- N 3 88888888888888888888821 & � a g g g g g g g 8 a a � � Noo �_W�U �i�6'cccccccoc ,`Sa y�. � a�o 88geo88g8888888888888' ;� S a "� ' O O O 0 0 0 0 0 U O O M W j w N 8 8 U U OWO W a a a' aaaejg'.? aXa � e e v1 0 o p° o 0 o a e o 0 C C O C s 6 tWJ N N 8 0 0 BOO oe 00 C C Q p to ZE 8888O888888888888888Ow86 3 •a X■ m � • c..N o =Jooa� w.- 000c000000 y Fn � xaae X � e a o � e 90 seo � 9se9 S 0 O� �D N . 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N 5.a+aa+a!ray. aw W N —o,. b=- �p000 Yy �C s¢aiw eN a c o ��ooccc �,o W 0000r.+�� fD Oo C a N oa cs7 z_ cv�a%a oa a 1a wa a� oa o 1w a a oa a a 00a b.a0-W aw a W a = R v o _ u. ♦♦ � � c. wrw�4a4ai{yy,,��� Q��o � Z �, i :.. ZZZ �' e J O W m O w a tJw a a ti a m a n n n n c^e n n n Z n W a f a a a c � 1 C CROSS-SECTION A (NORTHWEST-SOUTHEAST) GO bF 120.... ............ . . . . . . . . . . ... ........ . ..... . . . . . . . .. . .. ... ............... ............... 110 ............ ........... 100 .. ......... ........ ........... ............... . ......*....... 90 —------Qgt--:------ ------ . . ... ........ --- -------- ...... ... ............ 80 .. ... ...... . . . . ............. ....... ... ... ............... ............ ... . .. . .......... 70 ......Qga Qqg9a . . . . . .. .. ...... .... ....... .............. ............... . . . . . ......... 60 ..............-—--------------------------- 50 .. . .. :Qga. .. 40 0 150 1100 1150 1200 1250 300 Geotechnical Testing Laboratory FIGURE 4 Geotechnical Services 10011 Blomberg St.SW SCALE QA/QC Services Oly mpia,WA 98512 Phone:(360)7544612 V50' CROSS-SECTIONS Testing Services Fax:(360)7544848 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: Permit# 6" ' Z7 Parcel # Date(s)of the Document(s)reviewed:_ , (1) (a)A d'is us ion of general geologic conditions in the vicinity of the proposed development, OK? Comment: (b) A di c ssion of specific soil types OK? Comment: (c) A i cussion of ground water conditions OK? Comment: (d) A d ssion of the upslope geomorphology OK? Comment: (e) A s ssion of the location of upland waterbodies and wetlands OK? Comment: (f) A d cussion of history of landslide activity in the activity in the vicinity, as available in the referenced maps and records OK? (/ Comment: (2) A site plan which identifies the important development and geologic features. OK?40 Comment: (3) Locati ns logs of exploratory holes or probes. OK? omment: (4) The area f the proposed development, the boundaries of the hazard, and associated buffers and setback stiall be delineated(top, both sides, and toe)on a geologic map of the site. OK? Vjal Comment: (5) A mini um of one cross section at a scale which adequately depicts the subsurface profile, and which in oyporates the details of proposed grade changes. Ol ? `)Comment: (6) A descr' tion 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 seismip safety factor is 1.1. and the quasi-static analysis coeffients should be a value of 0.15. OK? qP5 Comment: (7) (a)Ap opriate restrictions on placement of drainage features OK? Comment: (b) A ro.p,riate restrictions on placement of septic drain fields OK? YYJ Comment: (c) App opriate restrictions on placement of compacted fills and footings OK? G 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: r (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. OK? �Comment: (8) Recorr4mendations for the prepaffation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. OK? �� Comment: (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope Pb rosion, landslides and harmful construction methods. OK. Comment: (10) An an�yis both on-site and off-site impacts of the proposed development. OK? omment: (11) Specifications of final development conditions such as, vegetative management, drainage, erosior 9(ontrol, and buffer widths. OK? '5 Comment: (12) Recommendations for the preparation of structural mitigation or details of other proposed mitiga i OK? 6o Comment: (13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and n� #u,�g of existing and progosed development on the site. OK? (-COI Comment: VZA'6VZe_ / Are the Documents signed and n ` stamped? `,/4//j Type and#of License: L&r_ � ' b�3�1 If not approved, what is the next action/recommendation for further action? Reviewed by , on Time spent in review: r�d&dez� . 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 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 DAN ROBINSON Parcel # 122285002901 Site Address 4593 E STATE ROUTE 302, BELFAIR,WA 98528 (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 9-11 (b) A discussion of specific soil types Located on page(s) 10-11 (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) 10-12 (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) 12-14 (7) (a)Appropriate restrictions on placement of drainage features Located on page(s) 15 (b) Appropriate restrictions on placement of septic drain fields Located on page(s) 15 (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) 15, 17-18 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) 15& 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) 15 & 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) 15 (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) 16& FIGURE 2 (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 16 (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) 16, FIGURE 2 & 3 (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) 17 (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 1, 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 August 06, 2009 and entitled 4593 E State Route 302, 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) Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. SITE PLAN WAS PROVIDED BY THE CLIENT. W "°a`ro""� nra+.owoe»� Geotechnical CONTOURS ARE BASED ON MASON COUNTY GIs AND OUR SITE RECONNAISSANCE CONDUCTED BY CURTIS D CUSHMAN ON TULY 23,2DD9. 2 Q + Testing 4 \ K O� f� Laboratory ek �\ z wo°°PortR tTfrpMal W B°rT°Y of RTFA W nT1FAOe E(MY1 YlEltwTf' rF"Nk"=%+t trnl0.MfE Pout O eax+.ke.kr p O �� 1 1 0� \I / roan 1 \\ Q I Geotechnical Services QA/QC Services Testing Services N 1 �� \ �� \ I � I � � / sea,oek.nroo+ecoa;+ni•"�aF f,,,,00�" 10011 Blomberg SL SW OI / "'K'"s°Em"`°""'e"'e°"°s"'"u''"s`°`F Ra""e° "_ Olympia,WA 98512 M Phone:(360)7544612 \ \ 1 A SL- O - / / I I / •°„E"oe,,:,a,.o`"ate"^`` " E'.t`No Fax:(360)754-4848 Date: 08/05/2009 \ \ \ ^1 / � / / / ewe n Designed by:CLIENT dJ \ \ X-/t Q I / QJ� / / �r.efr"mro "fes Drawn by:VC O N \\ \� \ �� (n I \/ Aga i // / / / O aaesnrosr s."v+oe Checked by: CDC y «.�." O \ \ \ 1 � � 1 � � / / � roars..,".+.o,++e"wro�sn+.s w.eoee wresfwk.tc. �'✓9R:08-05-09-013 � / / .�us,n`,"t�,�.°1.ewc�°s;.`:Fnww.®o"ecrk.ro O "w`sin"." 'a�+rHn"w`°a°r'.i umssrrazr�o.xoR \ \ I 57'S TBA6K 103'SETBAC SL \ 1 \ —479.71' PROJECT NAME: 9 E TAT ROBINSON STATE 4E ROUTE 302 \ \ \ \ BELFAIR,WASHINGTON PARCEL 122285002901 " Revisions: neS= wrEw�ae.m,.e,e. ae \ \ \\ / / / / rteeeuornn.rwnaofs \ rwkr"auuc wr.iw. \\\\ \\\ - ____-__-_-_- / // // °as snevesneo srswrrna�wns«°�o,r+�E �s� \ eeraa a"ne o""tarot srne�. NORTH \ / \� `------ / SCALE 1"=50' ••f a� " "� E`"�° sca so reel e:,aa= C.I.=2' FIGURE 2 -- - CaR[R C WenME pT+E OBrllan°"nE.ba PAOWFDf rrNr OlpwrM d•M VtKi"Tgn•nTNLBEp. 0 10 20 30 40 50 aim "n """TM E0'BrtaRRe "BOCV°°E SITE PLAN + nr�aoo,acre idle e[°eT"r1oN"eYTfYWfID. SITE PLAN WAS PROVIDED BY THECI.IENC. ` "°'��' Geotechnical CONTOURS ARE BASED ON MASON COUNTY GIs AND OUR SITE RECONNAISSANCE EaM CONDUCTED BY CURTIS D CUSHMAN ON NLY 23,2M. 2 a T e s ti n b Laboratory X'o j r OCTLjj s \ \ \ Cli \\ 11 \\ QO Geotechnical Services \ \\ 1 `"7"`"""° '. ,,.a,a«, QA/QC Services 1 \ Q I 1 / Testing Services ­SS °.e_ cu �. ure or ros°w.sursio�Fnw.«eewiEn Olympia,WA 98512I 10011 Blomberg SL SW Cc) \ Phone:(360)754-4612 \\ \ \ \ Q SL- O �f I I Fax:(360)754-4848 ,,.exs.=E--a E=—. —n«�.x °«� Date: 08/0512009 E-ETER \ \ \ \ \ 1 n I / , „ / / I FIX' , . Designed by:CLIENT \ \ \ \\ \ 17✓ I QJ�� i i / / �°.�E...E�n.°.wE ,r+°. �. 10rEnE.ancsK.i. Drawn by.VC O \ \ CQ I (�a' �' ' / o .". � Checked by:CDC D N \ \\ \ \ �' ����J �� f / Dwg#:08-05-00-013 cy i o 5T S TBAG�K i , / 0 103'SETBAC \ 1 1 ; �'� �• �� SL- � \ 1 \ —479.71' i O� `"11 ,�° ..° M�«�.�w PROJECT NAME: ROBINSON RESIDENCE 4593 E STATE ROUTE 302 BELFAIR,WASHINGTON S. PARCEL 122285002901 Revisions: T. T7:,�rowFEo r gw \ \ —————————— / / asu�Aca saEE. °r xEVE+aEs wEs NORTH .� .E °...��. R 5 SCALE:1 inh 50f SCALE 1"=50' �FSrtE� c = eel ­FLT = CAX. C.I. 2' `�°�`�° ­12. FIGURE 2 0 10 20 30 40 50 SITE PLAN FILTER FABRIC MATERIAL 6P WIDE ROLLS W OWIE SITE?LAN WAS PROVIDED BY THE CLIENT. FABRIC NARERIGTOATTACH TO W RE 2'X2'X14 GAUGE WIRE Geotechnical CONTOURS ARE BASED ON MASON COUNTY GIS AND OUR SITE RECONNAISSANCE (Y FABRIC OR EQUIVALENT CONDUCTED BY cuRTls D CUSHMAN ON IDLY 23,2009. Q Testing � z 6'4T a UND FACE 77/W/ Laboratory \O �, X //yyam� /�� ca Q 2'XW WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER / V �( O BETTER EQUAL ALTERNATE: MATERIAL IN 8'X/2"TRENCH � STEEL FENCE POSTS J �' FILTER FABRIC C OI` 2-A27(14 GAUGE HARE/ V C u FABRIC OR EQUIVALENT 7a �PJ /��\ v / GROUND SURFACE 5'd' O�V O� II O4 \\ ,� O / PROVIDE 3/4'-11?WASHED / GRAVEL BACKFILL IN TENCH 12" AND ON BOTH SIDES OF FILTER 1\ 1 h 1 �� \ // / FENCE FABRIC ON THE SURFACE r M �4Q 27,WODDPQBTB Geotechnical Services ACT:STEEL FENCE POSTS 1 FILTER FABRIC FENCE NOTES: o 1.FILTER FABRIC SHALL BE PURCHASED INA CONTINUOUS ROLL CUT TO LA/QC Services TH LENGTH OF THE ARE NECESSARY,FILTER CLOTH SHALIER TO L BESPLICEDI'TTOGETS THERONLYAT Testing Services / A SUPPORT POST WTH A MINIMUM&INCH OVERLAP AND SECURELY FASTENED AT BOTH ENDS TO THE POST. 2.POSTS SWILL BE SPACED A MAXIMUM OF S FEET APART AND DRIVEN / I I I SECURELY INTO THE GROUND(MINIMUM OF 30 INCHES). O 1 \ '1 \ \ i / ' i i / 3.ATENCHSHALLBEEXCAVATED APPROXIMATELY 8 INCHES WIDE AND 12 10011 Blomberg St.SW INCHES DEEP ALONG THE LIE OF POSTS AND UPSLOPE FROM THE BARRIER. / Olympia,WA 98512 4.VMEN STANDARD STRENGTH FILTER FABRIC IS USED,A WARE MESH M \ I SUPPORT FENCE SHALL BE FASTENED SECURELY TO'THE UPSLOPE S1DE Phone:(360)754-4612 OF THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST IINCH Fax:(360)754-4848 LONG,TIE WIRES OR HOC RINGS.THE WARE SHALL EXTEND INTO THE TRENCH A MINIMUM OF 41NCHES AND SHALL NOT EXTENDMORE THAN 36 I, INCHES ABOVE THE ORIGINAL GROUND SURFACE. 5.THE STANDARD STRENGTH FILTER FABRIC SHALL BE STAPLED OR WIRED Date: 08/05/2009 TO THE FENCE AND 201NDHES OF FABRIC SHALL BE EXTENDED \ \ \ � / �l ' I / / I INTO THE TRENCH.THE FABRIC SHALL NOT EXTEND MORE THAN36 Designed by:CLIENT \ \ INCHES ABOVE THE ORIGINAL OROUNO SURFACE.FILTER FABRIC SHALL '�� I NOT BE STAPLED TO THE EXISTING TEES. Drawn by: VC �-l \ \\ \ r� \/ I / ��/^� // / / S.WHEN EXTRA$TRENGTH FILTER FABRIC AND CLOSER POST SPACING IS Checked by: CDC N I V, / / O USED,THE WIRE MESH SUPPORT FENCE MAP BE ELIMINATED,IN SUCH \ • 1 / / O A CASE,THE FILTER FABRIC IS STAPLED OR WIRED DIRECTLY TOTE Dwg#:08-05-09-013 O' POSTS WITH ALL OTHER PROVISIONS OR ABOVE NOTES APPLYING. O 7.FILTER FABRIC FENCES SHALL NOT BE REMOVED BEFORE THE UPSLOPE 57' S TB Otd K� / // / / / C> AREA HAS BEEN PERMANENTLY STABILIZED. 103' SETBAC ' / / / B F RAINFALL ANILTER D AT LEAST DAILY DURING ROLONGEDRAINFALLC FENCES SHALL BE INSPECTED IMMEDIATELY F ANY EACH Q 1 i REQUIRED REPAIRS SHALL BE MADE IMAEDATELY. \\ \\ 1 11 1 , ST- GENERAL EROSION CpITRfX.NOTES: ` 1. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIOR TO THE \ �479.71 F � BEGINNINGOFCONSTRUCTION.THE PROJECT ENGINEER AND THE COUNTY SHALL INSPECT AND APPROVE THE INSTALLATION OF ' / // ` EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUCTION. 2.EROSION CONTROL MEASURES ARE NOT LIMITED TO THE ITEMS NIZ ON THIS PLAN.THE CONTRACTOR IS RESPONSIBLE FOR THE MO SALLATI NIOF EXAN ISTING NG OR PROPOSED INTAINANCE OF ALL EROSION FACILOL ITIES SEASUES. SILTSHALL SEToOFFSIITE ALLD.CPRRE SHALL OPERTIESETAKENTOPREVENTMGRATION PROJECT NAME: 3.THE CONTRACTOR SNALL MAKE DAILY SURVEILLANCE OF ALL EROSION ROBINSON RESIDENCE CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR ADDITIONS TNECESSARY THE EROSION CONTROL MEASURES THE CONTRACTOR SHALL PROVIDE 4593 E STATE ROUTE 302 ADDITIONAL ToSSA THE COUNTY NISPECTOR ANO�OR THE PROJECT ENGINEER.MEASURES AS DETERMINED PAILUREY TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL BELFAIR,WASHINGTON REOUIREMENTS MAY RESULT IN CIVIL PENALTIES BEING LEVIED PARCEL 122285002901 \ / A AGAINST THECONTRACTOR AND/OR PROJECT GAMIER. 4.DURING THE WET SEASON(NOVEMBER TO MARCH)ALL DISTURBED SOILS \ \ / SHALL BE STABILIZED WITHIN 48 HOURS AFTER STOP OF WORK EROSION e1�I �/�FI CONTROL MEASURES SHALL INCLUDE,BUT GT BE LIMITED TO, RevlSwnS, \ \ / COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WTH I / PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH, \ If / / PLACCE AS WCEANS REPEIRMITSF THE DISTURBED AREAS SHALL TAKE \ \ / / / / 5.ALL SEEDED OR SODDED AREAS SHALL BE CHECKED REGULARLY \————————-- / / / / TO MAKE SURE VEGETATIVE COVERAGE IS COMLETE.AREAS SHALL BE REPAIRED,RESEEDED,AND FERTILIZED AS EQUIREO. TRACKJNG OF SOIL OFFSITE WILL NOT BE ALLOWED.IF ANY SOIL IS TRACKED ONTO A COUNTY STREET,IT SHALL BE REMOVED BY THE END OF THAT WORKING DAY.ANY FURTHER TRACKING OF/ BE NTED BY SWEEPING OR WASHING OF THE VEHICLES D WILL N CLES TIRES \ \ \ \`_— ——————' / RE BEFORE DRIVING ON A COUNTY STREET. \ \ N.\ / 7.NO MORE THAN S00 LF OF TRENCH ON A DOWNSLOPE OF MORE THAN 5 PERCENT SHALL BE OPENED AT ONE TIME. �\ �_�-► EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OU TRENGHES. NORTH B.TRENCH DEWATERING DEVICES SHALL BE DISCHARGED INA MANNER THAT WILL NOT ADVERSELY AFFECT FLOWING STREAMS.DRAINAGE SYSTEMS OR G OFFSITE PROPERTIES. SCALE 1 11 5�1 10 ALL STORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJECT DURING SCALE:finch=50 feet CONSTRUCTION SHALL BE PROTECTED SO THAT SEDIMENT-LADEN WATER N. / WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM. \\ / 11.ALL OFF-SITE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE \ C.I. 1 SHALL BE PROTEGEES FROM BESILTATION, E RESPONSIBLE TO ENSURE THAT I w 72.ALL DISTURBED AREAS SHALL BE SEEDED OR SODDED UPON COMPLETION /V, OF WORK THE CONTRACTOR SHALL B COMPLETE COVERAGE OF THE DISTURBED AREAS IS PROVIDED 3 THAT GROWTH OF THE VEGETATION IS ESTABLISHED. 0 10 20 30 40 50 13,NOTCH BASINS SHALL TRAP SEDIMENT OR FILTER FABRIC MUST BE SITE PLAN PLACED CINDER GRATE UNTIL VEGETATION IS ESTABLISHED.