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HomeMy WebLinkAboutGRD2008-00002 - GRD Engineering / Geo-Tech Reports - 6/4/2008 122.52'50"W 122"52'30"W 122'52'10"W 122'51'50'W 122°51'30"W 12r5l'10"W 122°50'50"W 122°50'30"W 122'50'10"W 122'49'50"W 122.49'30'W 12!'49'10"W 122°48'50`W 122°48'30"W 122°48'10'W 122°47'50'W 122°4T30"W 122°4T10"W '0 47.31'30"N �_,_. <' 47°31'30' a C � Z 9�� y Z F N � <" J' S • 0 � �!a aT 1i • , pi0 1 m ��9 3+2 M-04 rn 3J v°o r ? ,. 5 24�N O l W A Panrherl�l-e �9 V �-LAKE qo NHS °i 47°31'20"N 47°31'20' O O act° I 9 4 �• tjp pQ �. Z 47°31'10"N '( ••,24 ? o o '1 23 2. 036 27 ,g` 2 0 S 032 47°31'0"N 47'31'0"N o e. 3 39 -. 0 1, 43 -44- _ 6ry 47°30'50"N ! 47"30'50' n) c �Ir, �` h �� (1± 4 4T U,414 t 49 47°30'40"N 5 5?' 3 303'` ,�••.. 47°30'40" .. 56 47°30'30"N e- I�,•,. CRF F er'- F! m 61 64 65 6 ti 47'30'20` �.1,.- a O° 47°30'10"N 47*30'10' h. /; .r� ,^,� ♦ 7*30'0`N Gate 47.30'0'N )( Tanktrap Fire Station O 7'29'S0"N 47°29'S0" +Y,_ a - Myi Communication Tower Other Road ° 47°29'40"N 47°29'40 - Highway M Major Public Road 47°29'30"N 47.29'30" �i._•. Mainline RR 7.29.20"N Seconds 47°29'20"N GJ C �/ Spur 47'29'1o"N y r Hood Canal Tree Farm 's ;• Olympic Property Group 47°29'0"N Miles 0 0.25 0.5 1 Feet 47"28'50"N 0 1,000 2,000 4,000 • �' Nov.28,2005-Color Ortho Image flown in July 2005 7°28'40"N 47°2840"N4 ORM Road Atlas 47 ' I t) �,i I a + �r1 ._' i�? •<O'A 47°28'30"N �) • °28'30" �y -- 9� Map Sheet 62 122'53'0'W 122'52'40"W 122°52'20"W 122°52'0"W 122°5'.'40"W 122"51'20"W 122'51'0"W 122*50'40"W 122*50'20"W 122°50'0"W 122*49'40"W 122*49'201W 122°49'0'W 122'48'40'W 122'48'20"W 122°48'0"W 22°4T40"W 122°4T20"W RECE ' KENNETH NEAL & ASSOCIATES MCC® - PLANNING CONSULTING ENGINEERING GEOLOGISTS 3314 Gibraltar Ct. S.E.,Olympia,WA 98501-3968 Telephone: (360)352-5125 Fax: (360)236-0201 of was e-mail: kengnea!@aolcom June 4,2008 '` �07 MEMORANDUM TO: Mason County Department of Community Development ATTENTION: Robert D.Fink,AICP,Planning Manager Engineering eol �i 100 FROM: Kenneth G.Neal,L.G.,L.E.G.,Principal Engineering Geologist SUBJECT: Review Comments—GRD 2008-00002 RKENNETH G.NE, ,� "Limited Geotechnical Engineering Report with Slope Stability Analyses, Proposed Parking and Camping Areas, Parcel No.'s 123172000000 & 12308000000, 770 Holy Glen Shire Lane, Belfair, Washington," prepared for Mr. Ron Cleveland by Krazan & Associates, Inc., dated April 21, 2008, updated and revised May 20,2008 The original report by the consultant was updated following my telephone call to Phil Haberman, Engineering Geologist of Krazan & Associates, on May 13. Our brief review of the original report identified elements of the Mason County Resource Ordinance (MCRO) geotechnical report requirements that were missing, so the telephone call was intended to provide Krazan & Associates an opportunity to meet the standards without our completing a formal review. There are several required items still missing from this report,and other issues: 1. The site map (or maps) must show important development and geologic features, property boundaries, scale, north arrow, and the location and nature of existing and proposed development on the site. While the site plan presented in the report does show the topography (which is not required), the top and bottom of the slope, test pit and cross section locations, and a general area designated "Cleared Area—Proposed Grass Field,"the locations of these features are not shown in reference to property boundaries or other known locations. The site plan included with the original report showed the area in relation to the existing unimproved access road, but still no reference to property boundaries or corners. 2. The following statement on Page 6 is troubling: "Our previous analyses were modeled with a much steeper slope configuration. We have revised the topographic cross section based on the most recent topographic map (provided by stormwater engineer)." This indicates that the consultant did not measure slope inclinations at the site, and may have not walked the slope being evaluated and analyzed. Representative cross-sections used for slope stability analyses should be measured, not based on unknown or unverified topographic data, and should show real surficial and interpreted subsurface characteristics. The cross-section presented in the report does not match characteristics shown on the analysis cross-section, and, although the report states it is based on the topographic map, it does not match the topography shown for the cross-section location. 3. There is no indication of areas proposed or recommended for stormwater management. "We understand that another consultant is providing recommendations for stormwater management." as stated on Page 9 does not relieve the consultant of responsibility for recommending buffers Mason County Department of Community Development GRD 2008-00002 June 4,2008 Page 2 and setbacks from slopes to limit the potential for creating an unstable condition by infiltrating water into near-surface soils. 4. There is also no indication of whether a septic system will be designed or constructed for this site, or how waste water from recreational vehicles or other sources will be managed. These sources,each individually or in combination,could potentially affect slope processes. Following our completion of this list of concerns, I discussed this project with Jim Scholz, the Mason County Planner assigned to this project. We understand from this discussion, that he has reviewed the available planning documents and environmental checklist, and that the only activities planned for the area shown on the site plan as "Cleared Area — Proposed Grass Field" are camping, and recreational activities such as jousting. There will be no water system, restrooms other than porta-potties, or any other facilities requiring drain fields or infiltration of water. We understand no recreational vehicle or other types of mechanized camping will be allowed; vehicles will reportedly be parked in an area on the opposite side of the primitive access road from the steep slope. None of this information was described in the geotechnical report, which should, as a document, be self-sufficient, without the need for referencing other documents in order to understand the scope of the project. From a practical standpoint, there appears to be no risk to the stability of the steep slope adjacent to the proposed grass field, as long as soil and timber removed during grading of the site is not pushed over the slope or piled along the top of the slope. The only likely effect of this action, if carried out correctly, would be loss of root cohesion (which would be insignificant on a near-level slope), and an increase in delivery of rain water to the ground during spring and summer months. This would not be likely to affect slope stability or erosion, if water is not directed towards or over, or allowed to pond along the top of the slope. For these reasons, in our judgment, even though the geotechnical report has serious defects and does not meet the standards outlined in the MCRO,the risk of initiating slope movement from the actions described above is so low that the additional costs of report preparation and a second review do not seem warranted. If you have any questions,please call. I can most easily be reached on my cell phone at 360-280-6180. 2 copies submitted KENNETH NEAL&ASSOCIATES CONSULTING ENGINEERING GEOLOGim 3314 Gibraltar Ct.SE,Olympia,Washington 98501-3968 (360)352-5125 lk co8 LIMITED GEOTECHNICAL ENGINEERING REPORT WITH SLOPE STABILITY ANALYSES PROPOSED PARKING AND CAMPING AREAS PARCEL No.'s 123172000000& 12308000000 770 HOLY GLEN SHIRE LANE BELFAIR,WASHINGTON PROJECT No.092-08034 APRIL 21,2008 UPDATED AND REVISED MAY 20,2008 Prepared for: MR.RON CLEVELAND 13914- 142ND AVENUE KPN GIG HARBOR,WASHINGTON 98329 Prepared by: KRAZAN&ASSOCIATES,INC. GEOTECHNICAL ENGINEERING DIVISION 11715 N.CREEK PARKWAY S.,C-106 BOTHELL,WASHINGTON 98011 (425)485-5519 RECEIVED MAY 2 2 MASON COUNTY PUELiC WOfZK,,-, . �® Krazan & ASSOCIATES, INC. i SITE DEVELOPMENT ENGINEERS � . R �. LJUN (19 20CS 2 111 MCCD - PLANNING LIMITED GEOTECHNICAL ENGINEERING REPORT WITH SLOPE STABILITY ANALYSES PROPOSED PARKING AND CAMPING AREAS PARCEL No.'s 123172000000&12308000000 770 HOLY GLEN SHIRE LANE BELFAIR,WASHINGTON PROJECT No.092-08034 APRIL 21,2008 Prepared for: MR.RON CLEVELAND 13914- 142ND AVENUE KPN GIG HARBOR,WASHINGTON 98329 Prepared by: KRAZAN&ASSOCIATES,INC. GEOTECHNICAL ENGINEERING DIVISION 11715 N.CREEK PARKWAY S.,C-106 BOTHELL,WASHINGTON 98011 (425)485-5519 e CEMKrazan & ASSOCIATES, INC. GEOTECHNICAL ENGINEERING • ENVIRONMENTAL ENGINEERING CONSTRUCTION TESTING & INSPECTION April 21, 2008 KA Project No. 092-08034 Updated and Revised May 20,2008 Mr. Ron Cleveland 13914 142nd Avenue KPN Gig Harbor,Washington 98329 RE: Limited Geotechnical Engineering Report with Slope Stability Analyses Proposed Parking and Camping Areas Parcel No.'s 12372000000& 12308000000 770 Holy Glen Shire Lane Belfair, Washington Dear Mr. Cleveland, In accordance with your request, we have completed an updated and revised Limited Geotechnical Engineering Investigation with Slope Stability Analyses for the referenced site. The results of our investigation are presented in the attached report. If you have any questions, or if we can be of further assistance, please do not hesitate to contact our office. Respectfully submitted, KRAZAN&ASSOCIATES, INC. q�4 L-- Phil A. Haberman,P.G.,P.E.G. Senior Engineering Geologist PH/gs With Offices Serving The Western United States 11715 N.Creek Parkway S.,C-106•Bothell,Washington 98011 • (425)485-5519•Fax: (425)485-6837 � 1 1'(Xa.Zan & A S S 0 C I A T E S, I N C. GEOTECHNICAL ENGINEERING • ENVIRONMENTAL ENGINEERING CONSTRUCTION TESTING & INSPECTION TABLE OF CONTENTS INTRODUCTION.............................................................................................................................................1 PURPOSEAND SCOPE...................................................................................................................................1 PROPOSEDCONSTRUCTION......................................................................................................................2 SITE LOCATION AND DESCRIPTION.......................................................................................................2 GEOLOGICSETTING....................................................................................................................................2 FIELDINVESTIGATION................................................................................................................................2 SOIL PROFILE AND SUBSURFACE CONDITIONS.................................................................................3 GROUNDWATER.............................................................................................................................................3 GEOLOGICHAZARDS...................................................................................................................................3 LandslideHazard..............................................................................................................................................3 ErosionConcern/Hazard...................................................................................................................................4 SeismicHazard.................................................................................................................................................5 SLOPESTABILITY ANALYSES...................................................................................................................5 CONCLUSIONS AND RECOMMENDATIONS...........................................................................................7 General.............................................................................................................................................................8 SitePreparation................................................................................................................................................8 Erosionand Sediment Control.........................................................................................................................8 Groundwater Influence on Structures/Construction........................................................................................8 Drainageand Landscaping...............................................................................................................................9 Testingand Inspection.....................................................................................................................................9 LIMITATIONS..................................................................................................................................................9 VICINITYMAP...................................................................................................................................Figure 1 SITEPLAN...........................................................................................................................................Figure 2 FIELDINVESTIGATION............................................................................................................ Appendix A With Offices Serving The Western United States 11715 N.Creek Parkway S.,C-106•Bothell,Washington 98011 •(425)485-5519•Fax: (425)485-6837 -�K,Y'aZan & ASS0C. IATES, INC. GEOTECHNICAL ENGINEERING • ENVIRONMENTAL ENGINEERING CONSTRUCTION TESTING & INSPECTION April 21, 2008 KA Project No. 092-08034 Updated and Revised May 20, 2008 LIMITED GEOTECHNICAL ENGINEERING REPORT WITH SLOPE STABILITY ANALYSES PROPOSED PARKING AND CAMPING AREAS PARCEL NO.'s 123172000000 & 12308000000 770 HOLY GLEN SHIRE LANE BELFAIR,WASHINGTON INTRODUCTION This report presents the results of our Geotechnical Engineering Investigation for the proposed grass parking and camping areas located at 770 Holy Glen Shire Lane in Belfair, Washington. Discussions regarding site conditions are presented herein, together with conclusions and recommendations pertaining to site preparation, slope stability, drainage and landscaping, and erosion control. A site plan showing the approximate exploratory test pit locations is presented following the text of this report in Figure 2. A description of the field investigation and the exploratory test pit logs are presented in Appendix A. PURPOSE AND SCOPE This investigation was conducted to evaluate the shallow soil and groundwater conditions at the site, to develop geotechnical engineering recommendations for use during construction, and provide information regarding the slope stability of the site slopes relative to the proposed construction. Our scope of services was performed in general accordance with our proposal for this project along with modifications through email confirmation. The proposal was dated March 21, 2007 (KA Proposal No. G08-042WAB)and included the following: • A site reconnaissance by a member of our engineering staff to evaluate the surface conditions at the project site. • A field investigation consisting of excavating and sampling five exploratory test pits that provided general coverage of the property to be developed. The exploratory test pits ranged in depth from 4 to 5 feet below the existing site grades (refusal on very dense glacial till). Offices Serving The Western United States 11715 N.Creek Parkway S.,C-106 9 Bothell,Washington 98011 •(425)485-5519•Fax:(425)485-6837 KA No. 092-08034 April 21, 2008 Updated and Revised May 20, 2008 Page No. 2 of 11 • Evaluation of the data obtained from the investigation and completion of engineering analyses to develop recommendations for use in the project design and preparation of construction specifications. • Preparation of this report summarizing our findings, the results of our analyses and our conclusions and recommendations for this investigation. PROPOSED CONSTRUCTION We understand that the proposed construction includes removing trees and stumps from a portion of the referenced parcels in order to create field areas for camping and parking. We understand that mass grading is not proposed and the areas will be vegetated with grass upon completion of the clearing. SITE LOCATION AND DESCRIPTION The project site is located at 770 Holy Glen Shire Lane in Belfair,Washington. The proposed field area is gently undulating and has been mostly cleared of vegetation. A steep slope area extends downward along the eastern edge of the proposed field area into a ravine/stream area. This slope is up to approximately 150 percent in magnitude within the uppermost portions and up to approximately 90 feet in height. The slope extends downward into a ravine with a stream. The property is vegetated with a mixture of evergreen and deciduous trees and typical forest undergrowth. The steep slope is vegetated with evergreen and deciduous trees and some undergrowth. GEOLOGIC SETTING The site lies within the central Puget Lowland. The lowland is part of a regional north-south trending trough that extends from southwestern British Columbia to near Eugene, Oregon. North of Olympia, Washington, this lowland is glacially carved, with a depositional and erosional history including at least four separate glacial advances/retreats. The Puget Lowland is bounded to the west by the Olympic Mountains, and to the east by the Cascade Range. The lowland is filled with glacial and nonglacial sediments consisting of interbedded gravel, sand, silt,till, and peat lenses. A review of the available geologic maps for the area of the site, indicate that the property is underlain by Vashon Glacial Till. Glacial till is typically characterized by an unsorted, nonstratified mixture of clay, silt, sand, gravel, cobbles and boulders in variable quantities. These materials are typically dense and relatively impermeable. The poor sorting reflects the mixing of the materials as these sediments were overridden and incorporated by the glacial ice. Vashon till is typically underlain by Vashon Advance Outwash. These materials are also typically dense to very dense and consist of a mixture of sand with minor amounts of gravel and silt deposited in front of the advancing glaciers. FIELD INVESTIGATION A field investigation consisting of excavating and sampling five exploratory test pits that provided general coverage of the area to be cleared and re-vegetated was completed to evaluate the subsurface Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21, 2008 Updated and Revised May 20, 2008 Page No. 3 of 11 soil and groundwater conditions. The exploratory test pits ranged in depth from 4 to 5 feet below the existing site grades. The excavation work was completed on April 15, 2008 with a client provided backhoe. Representative samples of the subsurface soils encountered in the test pits were collected and sealed in plastic bags. These samples were transported to our laboratory for further examination and verification of the field classifications. The soils encountered in the exploratory test pits were continuously examined and visually classified in accordance with the Unified Soil Classification System(USCS). SOIL PROFILE AND SUBSURFACE CONDITIONS The soils encountered in the exploratory test pits were generally typical of those found in the described geologic unit. All of the test pits encountered approximately 2 to 2.5 feet of medium dense, silty-fine to medium grained sand with variable amounts of gravel (weathered Glacial Till) underlain by dense to very dense, silty-fine to medium grained sand with variable amounts of gravel (Glacial Till). This material extended to the termination depths of the test pits (refusal on till). Additional information about the soils encountered may be found in the logs of the exploratory test pits in Appendix A. GROUNDWATER The exploratory test pits were checked for the presence of groundwater during and immediately following the excavation operations. Groundwater was not encountered in the test pits at the date and time of our field investigation. It should be recognized that water table elevations may fluctuate with time. The groundwater level will be dependent upon seasonal precipitation, irrigation, land use, and climatic conditions, as well as other factors. Therefore, water levels at the time of the field investigation may be different from those encountered during the construction phase of the project. The evaluation of such factors is beyond the scope of this report. Groundwater flow may become heavier during construction, which takes place during the wet weather season. This may cause difficulties with the grading and excavation work. Certain remedial and/or de- watering measures may be required. GEOLOGIC HAZARDS Landslide/Steen Slope Hazard The soils within the area of the proposed re-vegetation consist of glacial till. Glacial till is typically dense to very dense and typically suitable for construction in sloped areas. Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21,2008 Updated and Revised May 20,2008 Page No.4 of 11 We observed no head scarps, hummocky terrain, back rotated benches, sloughing soils, groundwater seepage emanating from slope faces and/or discontinuous vegetation patterns. We observed no tension cracks near the tops of the site slopes. In addition, we observed no bedding planes or joint systems within exposed slope areas. It is our opinion that the field areas may be located as proposed, provided adequate measures are taken to minimize erosion near/on the site slopes. The possibility for activating potential slide planes and/or accelerating general slope retreat does exist,if drainage and erosion are not properly managed. The removal of native vegetation should be limited, to the greatest extent possible (outside areas designated for landscaping) and landscaping and other permanent erosion control features should be in place to reduce adverse impacts to neighboring and down slope properties resulting from erosion. Vegetation should not be removed from steeper slope areas. It should be understood, due to natural geologic processes such as weathering and erosion due to rain, drying, wind, and rarely freeze/thaw cycles, the relatively steep site slopes slowly erode and retreat towards the west. This is a natural weathering and erosion process that affects this type of slope environment, and it is a continual, long-term process. Although it appears that the slopes are retreating at a relatively low rate at this time,it should be understood that the rate of slope retreat can increase due to natural weathering and erosion processes (severe weather and/or removal of slope vegetation) and this may impact future structures on the property. It should be noted that this type of erosion is common to these types of slopes and can be minimized. Erosion Hazard The Natural Resources Conservation Service (MRCS) maps of Mason County indicate that the site is underlain by Alderwood gravelly sand loam (5 to 15 percent slopes) with "Slight" to "Moderate" erosion potential is a disturbed state; Everett gravelly loamy sand (15 to 30 percent slopes), with "Moderate"to"Severe"erosion potential in a disturbed state; and Rough Broken Land with"Severe"to "Very Severe"erosion potential in a disturbed state. It has been our experience that soil erosion can be minimized through landscaping and surface water runoff control. The main soil work will consist of removing vegetation from the upper level area and re- vegetating with grass. Typically, erosion of exposed soils will be most noticeable during periods of rainfall and may be controlled by the use of normal temporary erosion control measures, i.e., silt fences, hay bales, mulching, control ditches or diversion trenching, and contour furrowing. Erosion control measures should be in place before the onset of wet weather. Erosion of slopes can be minimized using proper drainage and erosion control features. Erosion and retreat of slopes is typically maintained at a relatively low rate within this type of slope environment, if the natural vegetation is left in place, to the greatest extent possible (outside areas designated for landscaping and structural development) and landscaping and other permanent erosion control features are in place. It should be noted that the rate of slope retreat may accelerate if shallow slides and slope movement take place without proper mitigation. Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21,2008 Updated and Revised May 20, 2008 Page No. 5 of 11 Seismic Hazard It is our opinion, based on our subsurface explorations,that the Soil Profile in accordance with the 2006 International Building Code (IBC) is Soil Class D. We referenced the 2002 map from the U.S. Geological Survey(USGS)website to obtain values for Ss and S,. The USGS website includes the most updated published data on seismic conditions. The site specific seismic design parameters, peak ground accelerations (PGA), and adjusted maximum spectral response acceleration parameters are as follows: PGA 60.93% (2 percent of exceedance in 50 years) 33.63% (10 percent of exceedance in 50 years) Ss 135.70%of g S1 49.80%of g FA 1.0 Fv 1.5 Additional seismic considerations include liquefaction potential and amplification of ground motions by soft soil deposits. The liquefaction potential is highest for loose sand with a high groundwater table. The relatively dense soils interpreted to underlie the site are considered to have a low potential for liquefaction and amplification of ground motion. Slone Stability Analyses We have re-analyzed the slope stability of the current slope configuration using a generalized cross-section across the central portion of the property. The slope stability analyses are based on the subsurface data obtained during our exploration work and on the topography from available topographic maps, our site observations with a handheld clinometer, as well as a topographic map provided by the stormwater/drainage engineer Mr. James Bottem. We performed slope stability analyses using both conservative and realistic soil parameters to indicate the potential range of factors of safety. The commercially available slope stability computer program Slope/W was used to evaluate the stability of the existing site slopes. The slope stability was analyzed under static and seismic conditions. The program calculates factors of safety for potential slope failures and generates the potential rotational failure planes (relatively homogeneous soil typically has rotational slope failure planes). This software calculates the slope stability under seismic conditions using pseudo-static methods. The stability of the described configuration was analyzed by comparing observed factors of safety to minimum values as set by Mason County. A factor of safety of 1.00 is considered equilibrium and less than 1.00 is considered failure. The recommended minimum factor of safety for global stability is approximately 1.50 for static conditions and 1.10 for seismic conditions(per Mason County). Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21, 2008 Updated and Revised May 20, 2008 Page No. 6 of 11 We analyzed the slope stability under seismic loading conditions using the typical design event per Mason County(0.15 g). Our previous analyses were modeled with a much steeper slope configuration. We have revised the topographic cross section based on the most recent topographic map (provided by stormwater engineer). Also, we have added a traffic load surcharge of 250 pounds per square foot from the top of the slope for approximately 160 feet. The following are the estimated soil parameters used in our analysis and summary of results of the subject slope: First Analysis: Soil Parameters used in First Analysis Soil Description Density Cohesion Angle of Internal Friction cfj s (degrees) Medium Dense Till 120 250 34 Dense to Very Dense 120 600 40 Till Stability Results for Existing Slope Configuration(Static) Factor—of—Safety Factor-of-Safety Required Observed Overall Global Stability 2.46 1.50 Stability Results for Existing Slope Configuration(Seismic Coefficient 0.15g) Factor—of—Safety Factor-of-Safety Required Observed Overall Global Stability 1.88 1.10 Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21, 2008 Updated and Revised May 20,2008 Page No. 7 of 11 Second Analysis: Soil Parameters used in Second Analysis Soil Description Density Cohesion Angle of Internal Friction c s (degrees) Medium Dense Till 120 0 30 Dense to Very Dense 120 250 36 Till Stability Results for Existing Slope Configuration(Static) Factor—of—Safety Factor-of-Safety Required Observed Overall Global Stability 1.71 1.50 Stability Results for Existing Slope Configuration(Seismic Coefficient 0.15g) Factor—of—Safety Factor-of-Safety Required Observed Overall Global Stability 1.31 1.10 Our analyses indicate adequate factors of safety exist for static and seismic conditions for the existing slope configuration with the potential traffic surcharge load and using the two different sets of soil parameters including the most conservative set of parameters. CONCLUSIONS AND RECOMMENDATIONS General It is our opinion that the removal of vegetation from the level area above the steep slope will not increase the landslide hazard at the site if stormwater is managed and proper erosion control methods are in place during construction. We recommend that a minimum 10 feet wide buffer be maintained from the top of the steep slope area. In buffer areas where vegetation has been removed, we recommend that the area be sloped away from the slope. Loose stumps and other vegetation can be placed in that area. Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21, 2008 Updated and Revised May 20, 2008 Page No. 8 of 11 Landslide activity, such as shallow sloughs, should be expected on the steep slope area, and may occur at any time. However, if stormwater is managed and is not allowed to flow over the slope area, the proposed vegetation removal and re-vegetation will not increase the potential for landslide activity. Site Preparation General site clearing will include removal of most of the existing vegetation and root systems within the proposed camping/parking areas. This will be followed by rough leveling of the existing soils and planting with grass. If any specific recommendations are needed, we can provide them during construction. Erosion and Sediment Control Erosion and sediment control (ESC) is used to minimize the transportation of sediment to wetlands, streams, lakes, drainage systems, and adjacent properties. Erosion and sediment control measures should be taken and these measures should be in general accordance with local regulations. As a minimum, the following basic recommendations should be incorporated into the design of the erosion and sediment control features of the site: 1) Phase the soil, foundation, utility, and other work,requiring excavation or the disturbance of the site soils, to take place during the dry season (generally May through September). However, provided precautions are taken using Best Management Practices (BMP's), grading activities can be undertaken during the wet season(generally October through April),but it should also be known that this may increase the overall cost of the project. 2) All site work should be completed and stabilized as quickly as possible. 3) Additional perimeter erosion and sediment control features may be required to reduce the possibility of sediment entering the surface water. This may include additional silt fences, silt fences with a higher Apparent Opening Size (AOS), construction of a berm, or other filtration systems. 4) Any runoff generated by dewatering discharge should be treated through construction of a sediment trap if there is sufficient space. If space is limited other filtration methods will need to be incorporated. Groundwater Influence on Construction Groundwater was not encountered in the exploratory test pits at the date and time of our investigation. If groundwater is encountered during construction, it would most likely be perched. Perched groundwater develops where vertical infiltration of surface precipitation is impeded by a relatively impermeable soil layer, resulting in horizontal migration of the groundwater within overlying more permeable soils. Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21, 2008 Updated and Revised May 20,2008 Page No. 9 of 11 If earthwork is performed during or soon after periods of precipitation, the subgrade soils may become saturated. These soils may "pump," and the materials may not respond to densification techniques. Typical remedial measures include: discing and aerating the soil during dry weather; mixing the soil with drier materials; removing and replacing the soil with an approved fill material. A qualified geotechnical engineering firm should be consulted prior to implementing remedial measures to observe the unstable subgrade conditions and provide appropriate recommendations. Drainage and Landscaping We understand that another consultant is providing recommendations for stormwater management. We recommend that stormwater not be allowed to pond near the steep slope area or extend over the slope area at any time. Testing and Inspection A representative of Krazan & Associates, Inc. should be present at the site during the earthwork activities to confirm that actual subsurface conditions are consistent with the exploratory fieldwork. This activity is an integral part of our services as acceptance of earthwork construction is dependent upon compaction testing and stability of the material. This representative can also verify that the intent of these recommendations is incorporated into the project design and construction. Krazan & Associates, Inc. will not be responsible for grades or staking, since this is the responsibility of the Prime Contractor. Furthermore, Krazan & Associates is not responsible for the contractor's procedures, methods, scheduling or management of the work site. LIMITATIONS Geotechnical engineering is one of the newest divisions of Civil Engineering. This branch of Civil Engineering is constantly improving as new technologies and understanding of earth sciences improves. Although your site was analyzed using the most appropriate current techniques and methods, undoubtedly there will be substantial future improvements in this branch of engineering. In addition to improvements in the field of geotechnical engineering, physical changes in the site either due to excavation or fill placement, new agency regulations or possible changes in the proposed structure after the time of completion of the soils report may require the soils report to be professionally reviewed. In light of this, the owner should be aware that there is a practical limit to the usefulness of this report without critical review. Although the time limit for this review is strictly arbitrary, it is suggested that two years be considered a reasonable time for the usefulness of this report. Foundation and earthwork construction is characterized by the presence of a calculated risk that soil and groundwater conditions have been fully revealed by the original foundation investigation. This risk is derived from the practical necessity of basing interpretations and design conclusions on limited sampling of the earth. Our report, design conclusions and interpretations should not be construed as a warranty of the subsurface conditions. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21,2008 Updated and Revised May 20,2008 Page No. 10 of 11 The recommendations made in this report are based on the assumption that soil conditions do not vary significantly from those disclosed during our field investigation. The findings and conclusions of this report can be affected by the passage of time, such as seasonal weather conditions,manmade influences, such as construction on or adjacent to the site, natural events such as earthquakes, slope instability, flooding, or groundwater fluctuations. If any variations or undesirable conditions are encountered during construction,the geotechnical engineer should be notified so that supplemental recommendations can be made. The conclusions of this report are based on the information provided regarding the proposed construction. If the proposed construction is relocated or redesigned, the conclusions in this report may not be valid. The geotechnical engineer should be notified of any changes so that the recommendations can be reviewed and reevaluated. Misinterpretations of this report by other design team members can result in project delays and cost overruns. These risks can be reduced by having Krazan & Associates, Inc. involved with the design teams meetings and discussions after submitting the report. Krazan & Associates, Inc. should also be retained for reviewing pertinent elements of the design team's plans and specifications. Contractors can also misinterpret this report. To reduce this,risk Krazan&Associates. Inc. should participate in pre-bid and preconstruction meetings,and provide construction observations during the site work. This report is a geotechnical engineering investigation with the purpose of evaluating the soil conditions in terms of foundation design. The scope of our services did not include any environmental site assessment for the presence or absence of hazardous and/or toxic materials in the soil, groundwater or atmosphere, or the presence of wetlands. Any statements, or absence of statements, in this report or on any test pit log regarding odors, unusual or suspicious items, or conditions observed are strictly for descriptive purposes and are not intended to convey engineering judgment regarding potential hazardous and/or toxic assessments. The geotechnical information presented herein is based upon professional interpretation utilizing standard engineering practices and a degree of conservatism deemed proper for this project. It is not warranted that such information and interpretation cannot be superseded by future geotechnical developments. We emphasize that this report is valid for this project as outlined above, and should not be used for any other site. Our report is prepared for the exclusive use of our client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. Krazan&Associates,Inc. With Offices Serving The Western United States KA No. 092-08034 April 21, 2008 Updated and Revised May 20, 2008 Page No. 11 of 11 If you have any questions, or if we may be of further assistance, please do not hesitate to contact our office at(425)485-5519. Respectfully submitted, KRAZAN &ASSOCIATES,INC. o{ W ash; � A �G CO Engmeenng Geologist c 2513 �`' 32�5 ' t� Sed Ge° ���0�� `�j�NAL - S��ldB PHILLIP HABERMAN EXPiF',";GG1221 dB Phil Haberman, P.G., P.E.G. Gopal A. Singam, P.E. Senior Engineering Geologist Geotechnical Division Manager PH/gs Krazan&Associates,Inc. With Offices Serving The Westem United States N Vicinity Map { ° 0 N e } f 1 t + f iJ e' ,ter SITE 'P ii • - - • 4 or ol ` ' " r} � { f Ate•• .• � ,,� r • � ` • Y f . �� J<r;2LZ; �& ASSOCIATES, INC. Proposed Washington Renaissance Fantasy Faire Date: April 18, 2008 1 Vicinity Map Based on Maptech, 1999 Drawn By: BBC Figure 1 TProject Number: 092-08034 Site Plan II � / I / /,0, "Oo / T W 1 / / P- TP-5 / c7 � / / . A, / Cleared Area-Proposed TP-3/ Grass Field / / / / •, / / Approximate Graphic Scale / TP-4 / / / / • I I 100 0 100 200 / / 1 inch F200 feet LEGEND Test Pit Location �� i� Z& A S S 0 C I A T E S, I N C. TP-1 Proposed Washington Renaissance Fantasy Faire AN Cross Section (See Fig. 3) Date: April 17, 2008 Site plan based on data provided by drainage engineer A' Drawn By: BBC Figure 2 Project Number: 092-08034 Site [ ! ! ! I ! N S!t . , ► , , , ! !! i I !ji • liri r � , I Ir. i Undeveloped iiii i ' ' i r i it ; Land � O i ii i t i ! ' �• i r • r r r. Undeveloped Land i.' .'SI•opb Haziro i i g ►r rr Afedl rj •r I I , i � , i I I r. !iiri r i ; rli� TP-11 ±iii ! i Proposed i Grass/Field i i i Improvements liq iii TP-4 iii TP-4 r / iriii rr , TP-2 / !iiii / �� it i a � C-4 it rl. i / f' i9 it i i it i r ! ili Lo� // 11/ . ,i Vteep i �SIope Hazgrd ' Areal r , Undeveloped Land Not To Scale Test Pit Location 4" I�rc�Zar�& A S S O C I A T E S,I N C. rP-1 Proposed Washington Renaissance Fantasy Faire ate:April 17, 2008 1 Site Plan based on visual reconaissance Drawn By: BBC Figure 2 Project Number: 092-08034 Cross Section A - A A Approximate Top 450 of Slope 400 Approximate 2' Weathered Till Zone (not shown) i /��350 Very Dense Glacial Till A' 300 Stream 250 Vashon Advance Outwash? (inferred) 100 200 300 400 500 600 700 Oor Approximate Graphic Scale — r'a][71& A S S O C I A T E S, I N C. 50 0 50 100 ---------------- Estimated Topography Proposed Washington Renaissance Fantasy Faire 1 inch Feet feet Date: May 14, 2008 Project Number: 092-08034 Drawn By: PH Figure: 3 Ref: Eng. Provided Topo Map Slope Stability Results - First Analysis 200 190 • '80 250 psf Traffic Surcharge 170� 10[i 14! I'l; 120 -;110 Static CA 100 Pis I 15 90 80 70 60 50 40 30 20 10 0 13 0 510 20 30 40 50 60 70 80 90 10D 110 120 130 140 150 180 170 180 190 200 210 220 230 240 250 280 270 280 290 300 310 320 330 340 350 360 370 380 390 400 200 190 {' 180 17 17 250 psf Traffic Surcharge 1aG - —_— ,So 1 140 1 130 Seismic-0.15 g g ,00 A_ 15 SO 70 60 50 40 30 20 11 0 93 0 510 20 30 40 50 80 70 80 90 100 110 120 130 140 150 180 170 180 190 200 210 22D 23D 240 250 200 270 200 290 300 310 320 330 340 360 300 370 380 390 400 Length Medium Dense Weathered Glacial Till 34 Degree Friction Angle, 120 PCF,250 PSF Cohesion Dense to Very Dense Glacial Till 40 Degree Friction Angle, 120 PCF,600 PSF Cohesion i & ASSOCIATES' INC. Note:Weathered till is approximately 2 feet thick along the level areas and is thicker along the slope face. Proposed Washington Renaissance Fantasy Faire Date: May 15, 2008 1 Topo based on provided map and site obs Drawn By: PH I Figure 4 1Project Number: 092-08034 Slope Stability Results - Second Analysis 200 190 _ 180 17 250 psf Traffic Surcharge 160 150 140 130 12: F 11; Static S15 90 80 _ . 70 60 50 40 30 20 10 ". 14 0 0 510 20 30 40 50 W 70 90 90 1001101201301M 160 100 170 1e0 160 200 210 220 230 240 250 200 270 280 M 300 310 3W 330 W 350 360 370 M 3W 400 Length I 200 ]� ,90 • 1� 17 250 psf Traffic Surcharge Seismic-0.15 g 12 _ _ Ems __ 13 ,)10 10 3, 40 5G 60 70 80 90 10!1 110 120 130 140 150 160 170 180 190 2W 210 220 230 240 250 260 270 280 280 3W 310 320 330 340 350 3W 370 380 390 400 Length Medium Dense Weathered Glacial Till 30 Degree Friction Angle, 120 PCF,0 PSF Cohesion Dense to Very Dense Glacial Till 36 Degree Friction Angle, 120 PCF,250 PSF Cohesion Kraz;ar 1& ASSOCIATES, INC. Note:Weathered till is approximately 2 feet thick along the level areas and is thicker along the slope face. Proposed Washington Renaissance Fantasy Faire Date: May 15, 2008 1 Topo based on provided map and site obs Drawn By: PH Figure 5 Project Number: 092-08034 Appendix A Page A.1 APPENDIX A FIELD INVESTIGATION Field Investigation The field investigation consisted of a surface reconnaissance and subsurface exploration program for the proposed development. Five exploratory test pits were excavated and sampled for subsurface exploration at this site. The exploratory test pit depths ranged between approximately 4 and 5 feet below the existing grades. The approximate exploratory test pit locations are shown on the site plan in Figure 2. The depths shown on the attached test pit logs are from the existing ground surface at the time the test pits were excavated. The soils encountered were logged in the field during the exploration and, with supplementary laboratory test data,are described in accordance with the Unified Soil Classification System(USCS). All samples were returned to our Bothell laboratory for evaluation. The logs of the exploratory test pits are presented in this appendix. Krazan&Associates,Inc. Eleven Offices Serving The Western United States 092-07107doc KRAZAN AND ASSOCIATES LOG OF EXPLORATORY TEST PIT TP-1 11715 North Creek Parkway South Suite C-106 PROJECT:WARFF Bothell, Washington 98011 PROJECT NO.: 09208034 DATE:4/15/08 PAGE: 1 of 1 CONTRACTOR: Client SURFACE ELEVATION:Approx.410' SAMPLE METHOD:Grab LOCATION: Belfair,WA Natural Moisture Content and J -j w Atterberg Limits w a m J MATERIAL DESCRIPTION 0 2 J J Plastic Moisture Liquid a U Lu L a. Limit Content Limit o � N N 0 10 20 30 40 50 60 70 80 90 SILTY SAND WITH GRAVEL(SM) Medium dense,fine to medium grained sand, dark brown to dark reddish brown, moist. (Weathered Glacial Till) S-1 2 - ------------------------------------------ SILTY SAND WITH GRAVEL(SM) Dense to very dense,fine to medium grained sand, grayish brown, moist. (Glacial Till) S-2 3 4 i S-3 5 End of Exploratory Test Pit 6 7 8 Water Level Initial:0 Final: 1 Water Observations: None Encountered Notes: None KRAZAN AND ASSOCIATES LOG OF EXPLORATORY TEST PIT TP-2 11715 North Creek Parkway South PROJECT:WARFF Suite C-106 Bothell, Washington 98011 PROJECT NO.: 09208034 DATE:4/15/08 PAGE: 1 of 1 CONTRACTOR: Client SURFACE ELEVATION:Approx.420' SAMPLE METHOD: Grab LOCATION: Belfair,WA Natural Moisture Content and w Atterberg Limits O > m J MATERIAL DESCRIPTION z W LU Plastic Moisture Liquid _ w a a Limit Content Limit uj coQ 0 10 20 30 40 50 60 70 80 90 SILTY SAND WITH GRAVEL(SM) Medium dense,fine to medium grained sand, dark brown to dark reddish brown, moist. (Weathered Glacial Till) S-1 2 --------------------------------------------------------- SILTY SAND WITH GRAVEL(SM) Dense to very dense,fine to medium grained sand, grayish brown, 3 moist. (Glacial Till) I 4 End of Exploratory Test Pit 5 6 7 i 8 Water Level Initial: Final: Water Observations: None Enccountered Notes: None KRAZAN AND ASSOCIATES LOG OF EXPLORATORY TEST PIT TP-3 11715 North Creek Parkway South Suite C-106 PROJECT:WARFF Bothell, Washington 98011 PROJECT NO.: 09208034 DATE:4/15108 PAGE: 1 of 1 CONTRACTOR:Client SURFACE ELEVATION:Approx.410' SAMPLE METHOD: Grab LOCATION: Belfair,WA Natural Moisture Content and w Atterberg Limits -1 w a m w MATERIAL DESCRIPTION 0 Plastic Moisture Liquid = Cn w a ii Limit Content Limit oj < < 0 10 20 30 40 50 60 70 80 90 SILTY SAND WITH GRAVEL(SM) Medium dense,fine to medium grained sand, dark brown to dark reddish brown, moist. (Weathered Glacial Till) i 1 - 2 S-1 �Gj ----- ---------- SILTY SAND WITH GRAVEL(SM) Dense to very dense,fine to medium grained sand, grayish brown, 3 moist. (Glacial Till) i i 4 End of Exploratory Test Pit 5 6 7 8 Water Level Initial:0 Final: Water Observations: None Encountered Notes: None KRAZAN AND ASSOCIATES LOG OF EXPLORATORY TEST PIT TP-4 11715 North Creek Parkway South PROJECT:WARFF Suite C-106 Bothell, Washington 98011 PROJECT NO.: 09208034 DATE:4/15/08 PAGE: 1 of 1 CONTRACTOR: Client SURFACE ELEVATION:Approx.409' SAMPLE METHOD: Grab LOCATION: Belfair,WA Natural Moisture Content and w Atterberg Limits Lu m w MATERIAL DESCRIPTION 0 F J Plastic Moisture Liquid _ w a a Limit Content Limit Lu vi a a a 0 10 20 30 40 50 60 70 80 90 0 Di SILTY SAND WITH GRAVEL(SM) Medium dense,fine to medium grained sand, dark brown to dark reddish brown, moist. (Weathered Glacial Till) 1 2 --------------------------------------------------------- SILTY SAND WITH GRAVEL(SM) Dense to very dense,fine to medium grained sand, grayish brown, moist. (Glacial Till) 3 4 End of Exploratory Test Pit I 5 6 7 8 Water Level Initial: Final: Z Water Observations: None Encountered Notes: None KRAZAN AND ASSOCIATES LOG OF EXPLORATORY TEST PIT TP-5 11715 North Creek Parkway South Suite C-106 PROJECT:WARFF Bothell, Washington 98011 PROJECT NO.: 09208034 DATE:4/15/08 PAGE: 1 of 1 CONTRACTOR: Client SURFACE ELEVATION:Approx.425' SAMPLE METHOD: Grab LOCATION: Belfair,WA Natural Moisture Content and J w W Atterberg Limits m w MATERIAL DESCRIPTION 6 J w w Plastic Moisture Liquid _ w a a Limit Content Limit W (n a a a 0 10 20 30 40 50 60 70 80 90 SILTY SAND WITH GRAVEL(SM) Medium dense,fine to medium grained sand, dark brown to dark reddish brown, moist. (Weathered Glacial Till) 1 ' 2 --------------------------------------------------------- SILTY SAND WITH GRAVEL(SM) Dense to very dense,fine to medium grained sand, grayish brown, moist. I (Glacial Till) i 3 i I I 4=M End of Exploratory Test Pit i I i 5 i i 6 I 7 i I i 8 Water Level Initial:0 Final: 1 Water Observations: None Encountered Notes: None General Earthwork � Specifications . Appendix B Page B.1 APPENDIX B EARTHWORK SPECIFICATIONS GENERAL When the text of the report conflicts with the general specifications in this appendix, the recommendations in the report have precedence. SCOPE OF WORK: These specifications and applicable plans pertain to and include all earthwork associated with the site rough grading, including but not limited to the furnishing of all labor, tools, and equipment necessary for site clearing and grubbing, stripping, preparation of foundation materials for receiving fill, excavation, processing, placement and compaction of fill and backfill materials to the lines and grades shown on the project grading plans, and disposal of excess materials. PERFORMANCE: The Contractor shall be responsible for the satisfactory completion of all earthwork in accordance with the project plans and specifications. This work shall be inspected and tested by a representative of Krazan and Associates, Inc., hereinafter known as the Geotechnical Engineer and/or Testing Agency. Attainment of design grades when achieved shall be certified to by the project Civil Engineer. Both the Geotechnical Engineer and Civil Engineer are the Owner's representatives. If the contractor should fail to meet the technical or design requirements embodied in this document and on the applicable plans, he shall make the necessary readjustments until all work is deemed satisfactory as determined by both the Geotechnical Engineer and Civil Engineer. No deviation from these specifications shall be made except upon written approval of the Geotechnical Engineer, Civil Engineer or project Architect. No earthwork shall be performed without the physical presence or approval of the Geotechnical Engineer. The Contractor shall notify the Geotechnical Engineer at least 2 working days prior to the commencement of any aspect of the site earthwork. The Contractor agrees that he shall assume sole and complete responsibility for job site conditions during the course of construction of this project, including safety of all persons and property; that this requirement shall apply continuously and not be limited to normal working hours; and that the Contractor shall defend, indemnify and hold the Owner and the Engineers harmless from any and all liability, real or alleged, in connection with the performance of work on this project, except for liability arising from the sole negligence of the Owner of the Engineers. TECHNICAL REQUIREMENTS: All compacted materials shall be compacted to a density not less than 95 percent of maximum dry density as determined by ASTM Test Method D1557 as specified in the technical portion of the Geotechnical Engineering Report. The results of these tests and compliance with these specifications shall be the basis upon which satisfactory completion of work will be judged by the Geotechnical Engineer. SOIL AND FOUNDATION CONDITIONS: The Contractor is presumed to have visited the site and to have familiarized himself with existing site conditions and the contents of the data presented in the soil report. Krazan and Associates,Inc. Eleven Offices Serving The Western United States Appendix B Page B.2 The Contractor shall make his own interpretation of the data contained in said report, and the Contractor shall not be relieved of liability under the contractor for any loss sustained as a result of any variance between conditions indicated by or deduced from said report and the actual conditions encountered during the progress of the work. DUST CONTROL: The work includes dust control as required for the alleviation or prevention of any dust nuisance on or about the site or the borrow area, or off-site if caused by the Contractor's operation either during the performance of the earthwork or resulting from the conditions in which the Contractor leaves the site. The Contractor shall assume all liability, including Court costs of codefendants, for all claims related to dust or windblown materials attributable to his work. SITE PREPARATION Site preparation shall consist of site clearing and grabbing and preparations of foundation materials for receiving fill. CLEARING AND GRUBBING: The Contractor shall accept the site in this present condition and shall demolish and/or remove from the area of designated project, earthwork all structures, both surface and subsurface, trees, brush, roots, debris, organic matter, and all other matter determined by the Geotechnical Engineer to be deleterious. Such materials shall become the property of the Contractor and shall be removed from the site. Tree root systems in proposed building areas should be removed to a minimum depth of 1 foot and to such an extent which would permit removal of all roots larger than 1 inch. Backfill or tree root excavation should not be permitted until all exposed surfaces have been inspected and the Geotechnical Engineer is present for the proper control of backfill placement and compaction. Burning in areas, which are to receive fill materials, shall not be permitted. SUBGRADE PREPARATION: Surfaces to receive Structural fill shall be prepared as outlined above, excavated/scarified to a depth of 12 inches, moisture-conditioned as necessary, and compacted to 95 percent compaction. Loose and/or areas of disturbed soils shall be moisture conditioned and compacted to 95 percent compaction. All ruts, hummocks, or other uneven surface features shall be removed by surface grading prior to placement of any fill material. All areas scheduled to receive fill materials shall be approved by the Geotechnical Engineer prior to the placement of any of the fill material. EXCAVATION: All excavation shall be accomplished to the tolerance normally defined by the Civil Engineer as shown on the project grading plans. All over excavation below the grades specified shall be backfilled at the Contractor's expense and shall be compacted in accordance with the applicable technical requirements. FILL AND BACKFILL MATERIAL: No material shall be moved or compacted without the presence of the Geotechnical Engineer. Material from the required site excavation may be utilized for construction site fills provided prior approval is given by the Geotechnical Engineer. All materials utilized for constructing site fills shall be free from vegetable or other deleterious matter as determined by the Geotechnical Engineer. Krazan and Associates,Inc. Eleven Offices Serving The Western United States Appendix B Page B.3 PLACEMENT, SPREADING AND COMPACTION: The placement and spreading of approved fill materials and the processing and compaction of approved fill and native materials shall be the responsibility of the Contractor. However, compaction of fill materials by flooding, ponding, or jetting shall not be permitted unless specifically approved by local code, as well as the Geotechnical Engineer. Both cut and fill shall be surface compacted to the satisfaction of the Geotechnical Engineer prior to final acceptance. SEASONAL LIMITS: No fill material shall be placed, spread, or rolled while it is frozen or thawing or during unfavorable wet weather conditions. When the work is interrupted by heavy rains, fill operations shall not be resumed until the Geotechnical Engineer indicates that the moisture content and density of previously placed fill are as specified. Krazan and Associates,Inc. Eleven Offices Serving The Western United States Kraz I L 1 & ASSOCIATES , INC . GEOTECHNICAL ENGINEERING • ENVIRONMENTAL ENGINEERING CONSTRUCTION TESTING & INSPECTION April 1,2008 KA Project No.092-08034 i I Mr.Ron Cleveland 13914— 142"`'Avenue KPN Gig Harbor,Washington RE: Limited Geotechnical Evaluation Proposed Grass Field—Parking and Camping Areas Parcel No.'s 123172000000 and 12308000000 770 Holy Glen Shire Lane Belfair,Washington Dear Mr.Cleveland: At your request, we have prepared this letter to address proposed vegetation removal adjacent to a steep slope area. A Krazan & Associates senior engineering geologist visited the site on March 26, 2008 to observe the current site conditions. In preparation of this letter,we have reviewed the provided site Plans and available geologic mapping for the area of the site. Our scope of work includes visual observation of the current slope conditions and comments pertaining to the proposed vegetation removal and construction only. Detailed geologic hazard analyses are not included in our scope of work. PROPOSED CONSTRUCTION We understand that the proposed construction includes removing trees and stumps from a portion of the referenced parcels in order to create field areas for camping and parking. We understand that mass grading is not proposed and the areas will be vegetated with grass upon completion of the clearing. SITE LOCATION AND DESCRIPTION The project site is located at 770 Holy Glen Shire Lane in Belfair,Washington. The area of the proposed residence is gently sloping to the southeast and is currently partially cleared. A steep slope area extends downward along the eastern edge of the proposed field area into a ravine/stream area. This slope is up to approximately 150 percent in magnitude and up to approximately 90 feet in height. The property is vegetated with a mixture of evergreen and deciduous trees and typical forest undergrowth. The steep slope is vegetated with evergreen and deciduous trees and some undergrowth. Offices Serving The Western United States 11715 N.Creek Parkway S.,#C-106.Bothell,Washington 98011 •(425)485-5519•Fax:(425)485-6837 '0 0 wok M IL Parking area 1" = 250' saw V At M . ,a 40 � s 6... { . . a sirs tom ' 0 ATVW oil i James E. Baitem, P.E. WRFF 3/3112008 : Ar KA No.092-08034 April 1,2008 Page 2 of 3 STEEP SLOPE HAZARD A review of the available geologic map for the area of the site indicates that it is underlain by glacial till. Glacial till is typically dense to very dense and typically suitable for construction in sloped areas. We observed no head scarps, hummocky terrain, back rotated benches, sloughing soils, groundwater seepage emanating from slope faces and/or discontinuous vegetation patterns. We observed no tension cracks near the tops of the site slopes. In addition, we observed no bedding planes or joint systems within exposed slope areas. It is our opinion,based on the proposed development,that detailed slope stability analyses and additional geotechnical analyses for the site slope conditions are not warranted. It is our opinion that the field areas may be located as proposed, provided adequate measures are taken to minimize erosion near/on the site slopes. The possibility for activating potential slide planes and/or accelerating general slope retreat does exist, if drainage and erosion are not properly managed. The removal of native vegetation should be limited, to the greatest extent possible (outside areas designated for landscaping) and landscaping and other permanent erosion control features should be in place to reduce adverse impacts to neighboring and down slope properties resulting from erosion. Vegetation should not be removed from steeper slope areas. CONCLUSIONS AND RECOMMENDATIONS General It is our opinion that the proposed vegetation removal and grass field construction for use as parking and camping is suitable at this site and will not decrease the stability of the slope area or adjacent areas if proper erosion control measures are in place during vegetation removal. We recommend that erosion control measures are in place during construction and until landscaping is in place. Under no circumstances should stormwater runoff be allowed to channel and/or flow over the steep slope area. Erosion and Sediment Control Erosion and sediment control (ESC) is used to minimize the transportation of sediment to wetlands, streams, lakes, drainage systems, and adjacent properties. Erosion and sediment control measures should be taken and these measures should be in general accordance with local regulations. As a minimum, the following basic recommendations should be incorporated into the design of the erosion and sediment control features of the site: 1) Phase the soil, foundation,utility, and other work, requiring excavation or the disturbance of the site soils, to take place during the dry season (generally May through September). However, provided precautions are taken using Best Management Practices(BMP's), grading activities can be undertaken during the wet season(generally October through April). It should be understood that this typically increases the overall cost of the project. 2) All site work should be completed and stabilized as quickly as possible. Krazan&Associates,Inc. Offices Serving The Western United States KA No.092-08034 April 1,2008 Page 3 of 3 3) Additional perimeter erosion and sediment control features may be required to reduce the possibility of sediment entering the surface water. This may include additional silt fences, silt fences with a higher Apparent Opening Size (AOS), construction of a berm, or other filtration systems. 4) Any runoff generated by dewatering discharge should be treated through construction of a sediment trap if there is sufficient space. If space is limited other filtration methods will need to be incorporated. LIMITATIONS This geotechnical slope evaluation letter is based on limited observations of the current site conditions, and does not include a sub-surface evaluation of the site geological features or potential hazards. Any additional information required by Kitsap County with regard to the overall impact of the project is beyond the scope of this letter. If you have any questions, or if we may be of further assistance, please do not hesitate to contact our office at(425)485-5519. Respectfully submitted, KRAZAN&ASSOCIATES,INC. GOP 2. 513 �o w� /C) ZONAL Pha A.i fttrman D�IRES�l2'1Jo Phil Haberman,P.G.,P.E.G. Gopal A. Singam,P.E. Senior Engineering Geologist Geotechnical Division Manager PH/gs Krazan&Associates,Inc. Offices Serving The Western United States 122'52'SM 122.52'30'W 122.52'10"W 122'51'50"W 122.51'30"W 122.51'10"W 122.50'50'W 122.50'30'W 122.5010'W 122.49150"W 122.49'30"W 122°49'10'W 122°48'50"W 122.48.30"W 122.48'10'W 122°47'50'W 122*4r30"W 122'47'10"W 47°31'30"N4T31'30"N i O'o a°' S 47'31'20" ♦°p 3G Q D - �1�I ^�F` M O �``` r OAO �V 06 •7 ,' Z _._'--r 'O • 47'31'10"N o I We • 23 p.31 24-2 U O ° 47°31.0''N =7 ,°%� 2 0-1 0 S ••32 47.31'0'N i 3 2 M.or s Z 39 4D 1v 43 y I� p dry s 47°30'50"N r� i 47'30'50• Q I i I(i _ ♦ ti-t 4 47 11,4 49 ,A' v: )> •. 47.30'40"N47°30'40"N 5 j .{•••• 56 ', o 7 58,fL9k 3 4_ r '�• ♦ ti _7, 47°30'30"N ■1 47.30'30" +r CRF F e►•'- f' m '�J� f 6 t 8 _. J 5 64 65 6 i 47.30'20"N �• D 04 N / NM 47°30'10•N �✓ �a 47°30'0"N Gate 47`30'0"N - O9 i I I X Tanktrap N M. •°' Fire Station _° 47'29'S0"N 47.29'50" r ♦ �o Communication Tower "'. 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