Loading...
HomeMy WebLinkAboutGEO2021-00012 - GEO Geological Review - 10/3/2020 4. w 01EA 2.a21. OW►a�wv�rotecl� �w��weer�w�, ���c `2oa► o 16LAA1,01 nj waP-L C,eotechwi.cal° EwV�Y0V1vwewta[°Dra%vi.age°P0a0JwaU RECEIVED October 3,2020 JAN 1 1 2021 Michael Polo PLANNING 615 W. Alder Street 1677 NW Viewmont CT Silverdale,Washington 98383 RE: Geotechnical Report Addendum#3 for Polo Single Family Residence 190 NE Steelhead Drive S,Parcel 22325-50-06002 INTRODUCTION Envirotech Engineering (Envirotech) has completed this 3rd geotechnical report addendum for the above referenced single family residential property that is contiguous to the properties within our previous geotechnicaql studies. The original report, dated February 25, 2008, was prepared by Envirotech(Project #0828). Subsequent addendums were completed in order to add an adjacent parcel and to provide additional geotechnical recommendations. This addendum was prepared in order to provide parameters for the referenced parcel only. The original report identified the project as 212 NE Steelhead Drive S, Parcel 22325 44 01000. Since the completion of the original report, a residence was constructed and the parcel subdivided. Our geotechnical addendum#2 addresses the northern portion of the original parcel for the construction of an additional residence. Although this report addresses a separate parcel, this parcel is adjacent to the previous one, and has the same critical slope identified in the original. SUBSURFACE AND SURFACE CONDITIONS Information on surface and subsurface conditions are provided in the original report. A recent site visit was conducted by Robert McNearny, a representative with Envirotech on September 22, 2020. Soils were observed from cuts and test pits to be identical to the neighboring property.Landslides have not occurred, or new site conditions have not created indications of landslide susceptibility within the vicinity of the planned residence. DRAINAGE CONCLUSIONS Positive drainage should be provided in the final design for all planned residential buildings. Drainage shall include sloping the ground surface, driveways and sidewalks away from the project structures. All constructed surface and subsurface drains should be adequately maintained during the life of the structure. If drainage problems occur during or after construction, additional engineered water mitigation will be required immediately.This may include a combination of swales,berms,drain pipes,infiltration facilities, or outlet protection in order to divert water away from the structures to an appropriate protected discharge area.Leakage of water pipes,both drainage and supply lines,shall be prevented at all times. po�ox984 gel aLr, wash%w tow gs2g off: 360-2�5-93�4 Cell.: 360-009-6045 evwv rotech@geotechw%caliv fo.eon& t � For this project,we recommend that roof infiltration or dispersion is located at least 10 feet downslope of the proposed house, conforming to the Mason County Small Parcel Stormwater Plan. However, if space does not allow these standard systems,roof downspouts atop spash blocks may be utilized. VEGETATION BUFFER AND CONSIDERATIONS For this project, we believe that a detailed clearing and grading plan is not warranted unless Mason County thresholds are exceeded,and basic vegetation management practices should be adhered to. Vegetation Buffer—Vegetation shall not be removed from the face of the critical slope(40% or greater). However, any tree deemed hazardous to life or property shall be removed. See Other Considerations in this Addendum for mitigation if encroaching the buffer. If tree removal is necessary, then stumps and roots shall remain in place, and the underbrush and soil shall remain undisturbed as much as possible. Any disturbed soil shall be graded and re-compacted in order to restore the terrain similar to preexisting conditions and drainage patterns. See the Site Plan in Appendix A of this report for a depiction of the vegetation buffer. BUILDING AND FOOTING SETBACKS Provided that assumptions relating to construction occur and recommendations are followed as presented in this report, the factor of safety for slope stability is sufficient for a zero feet building setback from the toe of the critical ascending slope. The critical slope is defined as the point where the slope is 40% grade or steeper. The setback may be encroached if an engineered catchment wall is designed between the upslope and home,or incorporated into the home. OTHER CONSIDERATIONS The toe of the critical slope may be cut in order to increase the building pad area.However,an engineered catchment wall would be required in this case. The catchment wall will serve as structural mitigation for both vegetation buffer and building setback encroachment. Envirotech is pleased to submit this addendum for the Polo single family residence. Please contact Michael Staten at 360-275-9374 if you have any questions,comments,or require additional information. Best Regards, Envirotech En ineermg CLYDE s WAS h A 43045 <`vk ae RFCISTE4�r �ssIoNALE�G 10/3/20 Michael Staten,P.E. Project Manager Page 2 of 3 SCALE- I INCH = 60 FEET BUILDING SETBACKS NOT REQUIRED. SEE REPORT. ZERO VEGETATION F, BUFFER. SEE ADDENDUM SEPTIC DRAINFIELD AREA PROPOSED HOUSE QA lk CONTIGUOUS PARCEL IN ORIGINAL GEOTECHNICAL REPORT PROJECT/ OWNER/ LOCATION- SINGLE FAMILY RESIDENCE GEOTECHNICAL REPORT MICHAEL POLO 190 NE STEELHEAD DRIVE S NOTES LEGEND PARCEL 22325 50 06002 1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. MASON COUNTY, WASHINGTON GENERAL LOCATIONS, AND ALTERNATIVES TO SILT FENCES ENGINEER- MAY BE UTILIZED AS EXPLAINED IN THE GEOTECHNICAL ENVIROTECH ENGINEERING REPORT. PO BOX 984 2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SLOPE DIRECTION BELFAIR, WASHINGTON 98528 SURVEYOR, CONTOURS WERE EXTRAPOLATED FROM A PUBLIC 360-275-9374 LIDAR SOURCE, AND INCORPORATED FIELD MEASUREMENTS AS so EXISTING CONTOUR EXPLAINED IN THE GEOTECHNICAL REPORT. SITE PLAN Page 3 of 3 j_ — MASON COUNTY COMMUNITY SERVICES Building,Planning,Environmental Health,Community Health 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 is found not applicable, the report should explain the basis for the conclusion. Note:Unless specifically documented, this report does not provide compliance to the International Residential Code Sections R403.1.7 for foundations on or adjacent to slopes, Section R403.1.8 for expansive soils or section 1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes. Applicant/Owner Michael Polo Parcel# 22325-50-06002 Site Address 190 NE Steelhead Drive S (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 5 (original report) (b) A discussion of specific soil types, Located on page(s) 5 (original report) &2 (addendum 1) & 1 (addendum 3) (c) A discussion of ground water conditions, Located on page(s) 6 (original report) (d) A discussion of the upslope geomorphology, Located on page(s) 3 (original report) (e) A discussion of the location of upland waterbodies and wetlands, Located on page(s) 1 (addendum 2) (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) 9 (original report) & 1 (addendum 2) & 1 (addendum 3) (2) A site plan which identifies the important development and geologic features. Located on Map(s) Site Plan—addendum 3 (3) Locations and logs of exploratory holes or probes. Located on Map(s) Site Plan and Soil Logs (Appendix B) —original report (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) Site Plan—addendum 3 (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) Soil Profile (Appendix B)—original report (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. Located on page(s) 10 (original report) (7) (a) Appropriate restrictions on placement of drainage features, Rev. February 2018 i w Located on page(s) 2 (addendum 3) (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) 12 (original report) (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) 7 and 8 (original report) (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 2 (addendum 3) (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 2 (addendum 3) (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) 2 (addendum 2) None Required (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) 12 (original report) None Required (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 3 (addendum 2) (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) 12— 13 (original report) and 1 -2 (addendum 3) (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) 2 (addendum 3)—If required (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) Site Plan—Addendum 3 I, Michael Staten, hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical Report, dated October 3, 2020, and entitled Polo Single CLYbF ST Family Residence, meets all the requirements of the Mason County Resource Ordinance, Geologically Hazardous Areas Section, is complete and true, that the assessment demonstrates conclusively that the risks ,�f << 3E° \ti posed by the landslide hazard can be mitigated through 1013120 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. Page 2 of 2 Disclaimer:Mason County does not certify the quality of the work done in this Geotechnical Report. 7 Ev 'Woteoh Ev►otvieenvi3O, PL-L-c cjeotechvwi.cal o eovtronvu.ewtal o Drci uLw3e o R.oadwa� September 22,2018 Michael Polo 1677 NW Viewmont CT Silverdale,Washington 98383 RE: Geotechnical Report Addendum#2 for Polo Single Family Residence NE Steelhead Drive S,Parcel 22325-50-08904 I INTORDUCTION Envirotech Engineering(Envirotech)has completed this 2nd geotechnical report addendum for the above referenced single family residential property. The original report, dated February 25, 2008, was prepared by Envirotech (Project #0828). This addendum was prepared in order to provide revised information concerning the project. The original report identified the project as 212 NE Steelhead Drive S, Parcel 22325 44 01000. Since the completion of the original report, a residence was constructed and the parcel subdivided.This addendum addresses the northern portion of the original parcel for the construction of an additional residence. The critical slope identified in the original report is the critical slope affecting the new proposed building site. UPSLOPE WATER BODIES There are no apparent water bodies or wetlands located upslope from the planned development that would significantly influence the project. LANDSLIDE ACTIVITY Information on surface conditions are provided in the original report.A recent site visit was conducted by Michael Staten, geotechnical engineer with Envirotech on August 30, 2018. Landslides have not occurred,or new site conditions have not created indications of landslide susceptibility. DRAINAGE CONCLUSIONS Positive drainage should be provided in the final design for all planned residential buildings. Drainage shall include sloping the ground surface, driveways and sidewalks away from the project structures. All constructed surface and subsurface drains should be adequately maintained during the life of the structure. If drainage problems occur during or after construction, additional engineered water,mitigation will be required immediately.This may include a combination of swales,berms,drain pipes, infiltration facilities, or outlet protection in order to divert water away from the structures to an appropriate protected discharge area.Leakage of water pipes,both drainage and supply lines,shall be prevented at all times. pO E-oK904 gelfa�r, wash%v�.gtov,,9s52g Off: 360-2,-59374 CeL[; 360-689-6045 ewv%rotech@geotechw�cal�w fo.covu. If impervious thresholds are exceeded per Mason County code,then engineered stormwater management plans are required for this project.The drainage engineer must coordinate with a geotechnical engineer for input with relation to slope stability prior to submitting drainage plans. If stormwater management plans are not required for this project,then the following recommendations should be followed. Both footing perimeter drains and roof drains are required for this project. Subsurface water intercepted in the footing perimeter drains, and stormwater collected from roof drains shall be separately tight-lined to the recommended outlet. Roof and foundation drains may share a tightline if an above ground drainage outlet is allowable and a backflow preventer is installed within the pipe system in order to prevent roof water from entering the foundation area. For this project,we recommend that roof infiltration or dispersion is located at least 10 feet downslope of + the proposed house conforming to the Mason County Small Parcel Stormwater Plan. In addition p p g tY drainage facilities should be located outside setbacks and buffers as presented herein. i VEGETATION BUFFER AND CONSIDERATIONS For this project, we believe that a detailed clearing and grading plan is not warranted unless Mason County thresholds are exceeded,and basic vegetation management practices should be adhered to. Vegetation Buffer — Vegetation shall not be removed from the face of the critical slope or within a distance of zero feet beyond the top of the slope. However, any tree deemed hazardous to life or property shall be removed. If tree removal is necessary, then stumps and roots shall remain in place, and the underbrush and soil shall remain undisturbed as much as possible. Any disturbed soil shall be graded and re-compacted in order to restore the terrain similar to preexisting conditions and drainage patterns. See the Site Plan in Appendix A of this report for a depiction of the vegetation buffer. BUILDING AND FOOTING SETBACKS Provided that assumptions relating to construction occur and recommendations are followed as presented in this report,the factor of safety for slope stability is sufficient for a 40 feet footing setback from the face of the nearby descending slopes exceeding 40%. See the figure below and the Site Plan for an illustration of the setbacks. STRUCTURE TOP OF SLOPE SLOPE FACE _ I I—I IT —I I ' I� SETBACK I F❑❑TING From the illustration above, structures may be located closer to the top of slope by extending the foundation deep enough to maintain the recommended setback. In addition,the required setback may be reduced by mitigation, and subsequently would require additional geotechnical studies. Page 2of 3 ' I ON-SITE AND OFF-SITE IMPACTS j From a geotechnical position, it is Envirotech's opinion that the subject property and adjacent properties to the proposed development should not be significantly impacted if all recommendations in this report are followed. This is based on the expected site development, existing topography, land cover, and that the recommendations presented in this report are implemented. STRUCTURAL MITIGATION With respect to landslide alleviation or slope improvements,structural mitigation is not necessary for this j project. This determination is based on the anticipated improvements of the project, engineering conclusions,and compliance with all recommendations provided in this report. I OTHER CONSIDERATIONS Extensive earthwork may be performed near the top of slope in conjunction with the project. Earth cuts near the top of slope are permitted, and do not require to adhere to buffers or setbacks. Removing earth from the upper 1/3 of the slope will increase the stability of the slope.Fill should not be place beyond the slope top over the bank unless conforming to the earthwork requirements provided in the original report. In addition, the fill shall be benched into the hillside at widths of at least 8 feet. Otherwise, fill may be placed anywhere on the property outside of the geotechnical buffers and setbacks. CONSLUSION Envirotech is pleased to submit this addendum for the Polo single family residence. Please contact Michael Staten at 360-275-9374 if you have any questions,comments,or require additional information. Best Regards, Envirotech Engineering tiL C YDE s 0 4 AS T9T 43045 �I0 �L'GISTER� SSI�NAL", Michael Staten,P.E. Project Manager Page 3of 3 ATTACHMENTS 1. Site Plan 2. Mason County Checklist j i I SCALE, 1 INCH = 150 FEET ' i ROPOSED SIFT FENCE OR 73 to ALTERNATIVE EROSION CONTROL (IF NECESSARY) ROPOSED SINGLE FAMILY RESIDENCE (APPRX) 520FT 4 ell I SL PE OE a OPTIONAL SEPTIC SL PE TOP DRAINFIELD AREA I Z 0 V G TAT N B FFER A SOILS, MEDIUM PROPOSED SEP IC 5 / DENSE GLACIAL TILL i DRAINFIELD A A 4 OVERLYING DENSE I TO VERY DENSE I PAR EL 23 5 50 08904 ti~ ROPERTY LINE TILL y M 40' UIL IN SET AC F OM T P OF 07 S OPE I APPROXIMATE LOCATION OF ISSION CREEK T�2 ELL LCG LOCA ION F- o SLOPE TO 0 n i 10%t 6 i <5%t �3 5A SE OLD LOGGING ROAD FOR ACCESS 22> T¢ ,LtN 2p p PROJECT/ OWNER/ LOCATION, SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT MICHAEL POLO PARCEL 22325 50 08904 NOTES, LEGEND MASON COUNTY, WASHINGTON 1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE, GENERAL LOCATIONS, AND ALTERNATIVES TO SILT FENCES ENGINEER MAY BE UTILIZED AS EXPLAINED IN THE GEOTECHNICAL SILT FENCE ENVIROTECH ENGINEERING REPORT, SLOPE DIRECTION PO BOX 984 2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND BELFAIR, WASHINGTON 98528 SURVEYOR. CONTOURS WERE EXTRAPOLATED FROM A PUBLIC EXISTING CONTOUR 360-275-9374 LI➢AR SOURCE, AND INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEDTECHNICAL REPORT. TPIe TEST PIT SITE PLAN I MASON COUNTY Submittal Checklist COMMUNITY SERVICES Building,Planning,Environmental Health,Community Health Report Health 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 is found not applicable, the report should explain the basis for the conclusion. Note:Unless specifically documented, this report does not provide compliance to the International Residential Code Sections R403.1.7 for foundations on or adjacent to slopes, Section R403.1.8 for expansive soils or section 1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes. I I Applicant/Owner Michael Polo Parcel# 22325-50-08904 Site Address XXX NE Steelhead Drive S i (1) (a) A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 5(original report) I (b) A discussion of specific soil types, Located on page(s) 5(original report)&2 (addendum 1) i (c) A discussion of ground water conditions, I Located on page(s) 6 (original report) (d) A discussion of the upslope geomorphology, Located on page(s) 3(original report) i (e) A discussion of the location of upland waterbodies and wetlands, Located on page(s) 1 (addendum 2) (f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) 9 (original report) & 1 (addendum 2) (2) A site plan which identifies the important development and geologic features. Located on Map(s) Site Plan—addendum 2 (3) Locations and logs of exploratory holes or probes. Located on Map(s) Site Plan and Soil Logs (Appendix B)—original report (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) Site Plan—addendum 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) Soil Profile (Appendix B)—original report (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. Located on page(s) 10(original report) I 1 (7) (a) Appropriate restrictions on placement of drainage features, Rev. February 2018 Located on page(s) 1 (addendum 2) (b) Appropriate restrictions on placement of septic drain fields, Located on page(s) 12 (original report) (c) Appropriate restrictions on placement of compacted fills and footings, Located on page(s) 7 and 8(original report) i (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 2 (addendum 2) (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes. Located on page(s) 2 (addendum 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) 2 (addendum 2) (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) 12 (original report) (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) 3 (addendum 2) (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) 12— 13 (original report) and 1 -2 (addendum 2) (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. I i Located on page(s) 3 (addendum 2) i (13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of j existing and proposed development on the site. Located on Map(s) Site Plan—Addendum 2 I, Michael Staten, hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical Report, dated September 22, 2018, and entitled Polo CLYbC ST Single Family Residence, meets all the requirements of �t', o�WASIi the Mason County Resource Ordinance, Geologically Fr w� y _ Hazardous Areas Section, is complete and true, that the assessment demonstrates conclusively that the risks 43 TU, �� posed by the landslide hazard can be mitigated through �122178 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. Page 2 of 2 Disclaimer. Mason County does not certify the quality of the work done in this Geotechnical Report. P� zZ3zs�- �� - � I000 ALKAI CONSULTANTS, LLC. Environmental Engineering • Geotechnical Engineering • Wetland Consulting TO BE KEPT IN THE Pl 3 May 9,2008 PARCEL FILE 2-2 Mason County Department of Community Development lea El ./ R. P.O.Box 279I j Shelton,WA 98584 - f x ! Attn: Mr. Scholz ! I'M _ PLAN if Geotechnical Report Review Permit#BLD 2008-00181 Applicant: Polo Please find attached amendment letter as discussed in ALKAI's letter of approval dated May 5,2008. "There are minor house keeping issues with this report. Pages 3, 5, and 6 have three different statements regarding the soils samples taken or not taken at the site and their storage. ALKAI has contacted Mr. Staten directly to obtain an amendment to the report correcting this issue and will forward upon receipt." As stated ALKAI recommends that Mason County accept the geotechnical report. Should you have any questions or concerns, or if we may be of additional assistance, please call our office at (360)613-2407 or contact us by e-mail at Jim@alkai.net. Sincere , Jame Har mg,EIT Pro'`ct Engineer Attachments: Geo Tech Work Order Geotechnical Report: Envirotech Engineering Mason County Requirements Checklist 9465 Provost Road NW, Suite 202•Silverdale,Washington 98383 • (360) 613-2407• Fax: (360) 613-2408 Envirotech Engineering 74 NE Hurd Road, Belfair, WA 98528 May 5,2008 Michael Polo Y PO Box 3056 " Belfair, Washington 98528 `-� ._ RE: Geotechnical Report Addendum#1 for Polo Single Family Residence, Located F L �- At 212 NE Steelhead Drive S., identified as parcel number 22325 44 01000, _ Mason County, Washington C� INTORDUCTION Envirotech Engineering (Envirotech) has completed this geotechnical report addendum for the above referenced single family residence. The original report, dated February 25, 2008,was prepared by Envirotech(Project 40828).This addendum was prepared in order to provide revised information concerning subsurface investigation. In summary, the subsurface investigation included field testing such as relative density and visual classification of the soils. Soil sampling or laboratory testing was not performed for this project.The following sections correspond to the sections in the original report. 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the Project was gathered on March 18, and March 22, 2008 by Michael Staten, geotechnical engineer with Envirotech. Specific information on field methods, sampling, field testing, subsurface conditions, and results from soil testing are presented in this section of the report. Appendix C of this report includes pertinent information on subsurface conditions for the Project, such as subsoil cross-sections, test pit log(s) representative of the bearing soils of the planned building, and water well report(s). Applicable test pit and well log locations are depicted on the Site Plan and Geologic Map provided in the appendix of this report. 3.1 Field Methods,Sampling and Field Testing Information on subsurface conditions for the Project was accomplished by examining soils within test pits extending to depths of up to 10 feet below the existing ground surface, and reviewing a recent well report on the property to a depth of 57 feet below the ground surface.No soil samples were collected for this Project. Envirotech measured the relative density of the near-surface in-situ soils by gauging the resistance of hand tools. Within testing locations, field testing results generally indicated loose to medium dense soils in the upper 12 inches, dense from 12 inches to 5.5 feet, and very dense soils from 5.5 feet to the depth of terminous. Envirotech Engineering 74 NE Hurd Road, Belfair, WA 98528 3.2 General Geologic Conditions In general, soils at the project are composed of materials from glacial advances. The geologic conditions as presented in the "Geologic Map of Washington," compiled by J. Eric Schuster, 2002 indicates Quaternary sediments, Qg. Quaternary sediments are generally unconsolidated deposits, and dominantly deposited from glacial drift, including alluvium deposits. This project is located within the Puget Lowland. Typically, "lower tertiary sedimentary rocks unconformably overlie the Crescent Formation."as revealed in the Geologic Map. Initial sedimentary rocks were,formed from shales, sandstones and coal deposits from rivers. During the Quaternary period, the Puget Lowland was covered by numerous ice sheets, with the most recent being the Fraser glacier with a peak of approximately 14,000 years ago. Upon the glacial retreat, the landscape was formed by glacial erosion glacial drift deposits. 3.3 Specific Subsurface Conditions The following subsurface conditions are estimated descriptions of the Project subgrade utilizing information from the depth of penetration at all testing, observed and investigated locations. Soils for this project were described utilizing the Unified Soil Classification System (USCS). Using the USCS in conjunction with estimated relative densities and other anticipated engineering properties of the soil, susceptibility for potential landslides,erosion and seismic hazards may be assessed. The Project is composed of native soils with no indications of borrowed fill. For engineering purposes, these native soils consist of distinguishable layers, as presented below. Soils within the upper 10 feet of natural ground were observed to be moist, brown poorly- graded gravel with silt and sand(GP-GM).The relative densities of this soil are provided in Section 3.1 of this report. Gravels are primarily coarse, and subrounded. Sand content was primarily medium and coarse.The fines content exhibited none to low plasticity. According to the well reports and knowledge of the general area, soils below the observed 10 feet in depth are dense to very dense soils consisting mostly of sand and gravel. 3.3.1 Groundwater From the water well report, permanent groundwater is approximately 26 feet directly below the property at the building pad location. Perched groundwater at shallow depths was not observed on-site,nor indicated on the well reports. 3.4 Soils Testing Envirotech Engineering 74 NE Hurd Road, Belfair, WA 98528 Visual classification of soils was performed in the field. The following soil tests were performed in accordance with the American Standards for Testing and Materials (ASTM): 3 Visual Classifications(ASTM D2488) 3.4.1 Visual Classification The results from the visual classification are presented above in the Subsurface Conditions Section at depths of up to 10 feet below the natural ground surface. Specifically, soils within the upper 10 feet consisted of approximately 60% gravel, 30% sand-sized soils, and less than 10% silt. Minor variations observed during the visual classification of particle size content (i.e. gravel, sand, fines), or isolated pockets within the soil stratification were insignificant in relation to the overall engineering properties of the soil. CONSLUSION Envirotech is pleased to submit this addendum for the Polo single family residence. This addendum provided corrections and/ or additional information concerning the project. Conclusions and/ or recommendations did not change from the original geotechnical report. Please contact Michael Staten at 360-275-9374 if you have any questions, comments,or require additional information. Best Regards, Envirotech Engineering Michael Staten,P.E. Project Manager ,P KRV E D Geotechnical Report for Polo Single Family Residence 212 NE Steelhead Drive S. Parcel 22325 44 01000 Mason County, Washington February 25, 2008 Project#0828 Prepared For: Michael Polo PO Box 3056 WASH�ti'9r�, Belfair, Washington 98528 �w Prepared By: t i Envirotech Engineering A�o�F'��43945 � 74 NE Hurd Road SSI NA,,e�'�' Belfair, Washington 98528 Phone: 360-275-9374 EXPIRES JAN 10,20M Fax: 360-275-4789 rInTed fromanon Countv DMS d. TABLE OF CONTENTS 1.0 INTRODUCTION...........................................................................................................................1 1.1 PROJECT INFORMATION............................................................................................................... 1 1.2 PURPOSE OF INVESTIGATION........................................................................................................ 1 1.3 SCOPE OF WORK...........................................................................................................................1 2.0 SURFACE CONDITIONS....»........................................................................................................3 2.1 GENERAL OBSERVATIONS............................................................................................................3 2.2 TOPOGRAPHY...............................................................................................................................3 ZZI147slW GromorpholoV.......................................................................................................3 ZZ2 Downs&pe Geomorphology..................................................................................................3 2.3 SURFACE DRAINAGE.....................................................................................................................4 2.4 SLOPE AND EROSION OBSERVATIONS...........................................................................................4 3.0 SUBSURFACE INVESTIGATION ..». 5 3.1 FIELD METHODS,SAMPLING AND FIELD TESTING........................................................................5 3.2 GENERAL GFALOGIC CONDITIONS...............................................................................................5 3.3 SPECIFIC SUBSURFACE CONDITIONS.............................................................................................5 111 Grouxd►paff.........................................................................................................................6 3.4 So"TESTING.............................................................................................................................6 14.1 Ksual Qassification............................................................................................................. 4.0 ENGINEERING ANALYSIS,CONCLUSIONS AND RECOMMENDATIONS..........................7 4.1 BUH.DING FOUNDATION RECOMAZENDATIONs..............................................................................7 4.L I Bearing Capacity.................................................................................................................. 7 4.L2 SdtlawaRt............................................................................................................................. 7 4.2 LATERAL EARTH PRESSURES........................................................................................................8 4.3 EARTHWORK CONSTRUCTION RECOMMENDATIONS....................................................................8 4.11 F.zeavaden............................................................................................................................8 4.3.2 Placement and Compaction of Nadw Soils and ERgiseered Fill..........................................8 4.3.3 Rddxing Wall BachgW........................................................................................................ 9 4.34 Wet Wearier Comsidaaions.................................................................................................9 4.4 SLOPE STABH.TPY AND EROSION CONTROL..................................................................................9 4.4.1 SeVdcDr infuidlmpacts.................................................................................................... 12 4.4.2 Builifing and Footing Setbacks........................................................................................... 12 4.13 Ta%vwwy and Pprmsanent Erosion CombW....................................................................... 12 4.4.4 Surface and Subsurface Drainage...................................................................................... 13 4.45 Vegetation Considerations.................................................................................................. 13 4.4.6 O,(j-sde impacts................................................................................................................... 14 4.5 SEISMIC CONSIDERATIONS AND LIQUEFACTION......................................................................... 14 5.0 CLOSURE....................................«...............................................................................................15 Appendix A-Site Plan Appendix B-Geologic Map Appendix C-Soil Information Soil Profile Soil Logs Well Reports Appendix D-Slope Stability Input&Output Appendix E-Erosion Control 1.0 INTRODUCTION Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a property located at 212 NE Steelhead Drive S., identified as parcel number 22325 44 01000, Mason County,Washington(Project). As presented herein,this report includes information pertaining to the Project in this Introduction Section; observations of the property and surrounding terrain in the Surface Conditions Section; field methods and soil descriptions in the Subsurface Investigation Section; and, recommendations for foundation, settlement, earthwork construction, lateral earth pressures, slope stability, erosion control, drainage and vegetation considerations in the Engineering Analysis and Recommendations Section. An initial geotechnical evaluation of the Project was conducted by Envirotech with the property owner representative, Michael Polo, on March 18, 2008. It was determined that slopes in excess of 40% with a vertical relief of at least 10 feet were present within 300 feet of the planned development. Consequently, the proposed development will require a geotechnical report f Mason County Resource Ordinance 17.01.100. During the pursuant to Landslide Hazard Areas o rnY $ site visit by Envirotech,surface and subsurface conditions were assessed. After completion of the Project research Envirotech prepared this cotechnical report. livable o ct field work and applicable ) prep g 1.1 Project Information Information pertaining to the Project was provided by the property owner's representative with general assumptions by Envirotech that are typical of this type of development. The Project is accessed from NE Steelhead Drive, linking Mission Creek Road. See the vicinity map on the following page of this report. The property is currently vacant land. The planned development consists of a 1-story manufactured home. Foundation construction is expected to consist of isolated footings or strip type foundations typical for manufactured homes. Anticipated construction other than the residence will include an on-site septic system, and possible ancillary features typical of single family development. Approximate building footprint with relation to site features are illustrated in the Site Map in Appendix A. 1.2 Purpose of investigation The purpose of this geotechnical investigation was to evaluate the Project in order to provide geotechnical recommendations relating to the development of the property. The investigation included characterizing the general Project surface and subsurface conditions, and evaluating the suitability of the soils to support the planned site activities. 1.3 Scope of Work In order to fulfill the purpose of investigation, the geotechnical program completed for the proposed improvements of the Project include: • Review project information provided by the Project owner and/ or owner's representative; • Conduct a site visit to document the site conditions that may influence the construction and performance of the proposed improvements, • Define the general subsurface conditions of the site by observing subsoils extending to a depth of up to 10 feet below the natural ground surface, review geological maps for the Envirotech Engineering Geotechnical Investigation Ph. 360-275-9374 page 1 Parcel 22325 44 01000 Fax: 360-275-4799 Mason County, Washington March 25, 2008 general area, research published references concerning slope stability, and review water well reports from an existing well on the property-, • Perform soils testing to determine selected index properties of the soils that include 3 visual classifications; • Complete an engineering analysis supported by the planned site alterations, and the surface and subsurface conditions that were identified by the field investigation, soil testing,and applicable project research;and, • Establish conclusions based on findings, and make recommendations for foundations, drainage, slope stability, erosion control, earthwork construction requirements, and other considerations. ' � - o k.iaon 1.aM � t T m W e we aem OR ,�* z _ � Z � Z s Project ad�� xocwo.cANA Vicinity Map from Mason County Website i j]t 4 S Envirotech Engineering Geotechnical Investigation Ph. 3&)-275-9374 page 2 Parcel 22325 44 01000 Printed �"o�'�'l Mason County CAMS Mason County, Washington March 25,2008 Prir:ted from Mason County DIMS 2.0 SURFACE CONDITIONS Information pertaining to the existing surface conditions for the Project was gathered on March 18,2008 by Michael Staten,geotechnical engineer with Envirotech. During the site visit,the type of geotechnical investigation was assessed, site features were documented that may influence construction and slope stability, soil samples were collected from selected locations, and near- surface soils were visually classified. This Surface Conditions Section provides information on general observations, vegetation, topography, drainage and slope/ erosion conditions for the Project and surrounding areas that may impact the Project. 2.1 General Observations The Project is currently undeveloped land as previously mentioned. An existing dirt driveway extends from Steelhead drive,through the property, and to the south. Beyond the property lines, rural residential development exists with moderate density. Mission Creek is located over 300 feet to the east of the planned building location. Mostly dense vegetation on and near the Project consists primarily of alders,maples,hemlocks, and other trees and shrubbery common to this area of the Pacific Northwest. An aerial photo of the project and immediate vicinity is provided on the following page. 2.2 Topography The Project is situated within and near moderate to steep sloping terrain. Ile planned building envelope location is on slightly sloping ground of less than 5%. The topographic information provided in this section was extrapolated from a public lidar source, and incorporated observations and field measurements. Slope verification included measuring slope lengths and inclinations with a cloth tape and clinometer. See the Site Map in Appendix A and the Geological Map in Appendix B in this report for an illustration of general topography with respect to the planned development. 2.2.1 Upslope Geomorphology Ascending grades consisting of two distinguishable hills are located to the northwest and southwest of the planned development. Both slopes have similar geology, and the northwest slope was used as the critical design slope due to slightly steeper grades. The northwest ascending slope has grades of primarily 45% with a vertical relief of 51 feet. The southwest ascending slope has a vertical relief of nearly 90 feet. However, slope grades consist of almost 43% on the lower portion of the hill, and 22% on the upper portion. There are no apparent water bodies or wetlands located upslope from the planned development. 2.2.2 Downslope Geomorphology Descending grades of approximately 10% exist to the east of the planned development with a vertical relief of approximately 38 feet. Mission Creek is located at the toe of the descending slope. --------- - -------- ----- - -- Emirolcch Engineering Gcotcchnical Imcstigalion Ph. .�blt-?7;')Z?� pa_�c ; Parcel 22125 44 01000 F,tx 60-2'i_4789 Mason Count. 1Vashinglon March 25. 1008 ts��rr��,# � a""a'�+ra�axltfi:�r..a�R' ,`;.! rtnA;...r:',er ara?.vz§z�steu;•;�,t�a�.xr::;u�r,,;�r&X'.+«e"a%r1A �., .,,r.xra.,r.,.- :;:„.., ..,,.,. .... 2.3 Surface Drainage o be Stormwater runoff originating upslo low is eth�ecdowwnn tdevelopment e vhillsidesntowards the lanned minimal to moderate. Minimal sheet development on path towards Mission Creek. Between the two hills, a buildings. Although somesomle�water a wide Swale may transport moderate flows near the proposed r on the surface, excessive scour, erosion or other flow was apparent from the organic matte problems were not observed at the planned development. Excessive indications of past drainage p of Mission Creek during December of 2007 was apparent scour and erosion due to the flooding within an area of 100 feet west of Mission Creek. 2.4 Slope and Erosion Observations The existing steep slopes near the Project signal a potential landslide or erosion hazard area. Some indicators that may suggest past slope movements include: Outwash of sediments near the bottom of the slope, Fissures,tension cracks or naturally stepped land masses on the face or top of the slope, and parallel to the slope, Fine,saturated subsurface soils, Old landslide debris, Significant bowing or leaning trees,or, Slope sloughing or calving. Significant mass wasting on the property or within the general vicinity of the project were not observed or discovered during rficiai slope Indications Were of observed during the ssit unstable deep-seated slope problems,or su r;. a� Aerial photo from Mason County Website —____-- (3cotechnical lm estigatiort Envirotech Engineering Page Parcel 22325 44 01000 '= Ph. 360-275-g274 Mason CounIN.Washington [ 1 ,-;_4 S<) March 25,2008 rinte 3.0 SUBSURFACE INVESTIGATION Information on subsurface conditions pertaining to the Project was gathered on March 18, and March 22, 2008 by Michael Staten,geotechnical engineer with Envirotech. Specific information on field methods, sampling, field testing, subsurface conditions, and results from soil testing are presented in this section of the report. Appendix C of this report includes pertinent information on subsurface conditions for the Project, such as subsoil cross-sections, test pit log(s) representative of the bearing soils of the planned building, and water well report(s). Applicable test pit and well log locations are depicted on the Site Plan and Geologic Map provided in the appendix of this report. 3.1 Field Methods,Sampling and Field Testing Information on subsurface conditions for the Project was accomplished by examining soils within test pits extending to depths of up to 10 feet below the existing ground surface, and reviewing a recent well report on the property to a depth of 57 feet below the ground surface. No soil sampling was collected for this Project. Envirotech measured the relative density of the near-surface in-situ soils by gauging the resistance of hand tools. Within testing locations, field testing results generally indicated loose to medium dense soils in the upper 12 inches, dense from 12 inches to 5.5 feet, and very dense soils from 5.5 feet to the depth of terminous. 3.2 General Geologic Conditions In general, soils at the project are composed of materials from glacial advances. The geologic conditions as presented in the "Geologic Map of Washington," compiled by J. Eric Schuster, 2002 indicates Quaternary sediments, Q8. Quaternary sediments are generally unconsolidated deposits,and dominantly deposited from glacial drift, including alluvium deposits. This project is located within the Puget Lowland. Typically, "lower tertiary sedimentary rocks unconformably li Crescent Formation."as revealed in the Geologic Map. Initial sedimentary overlie the C og ap rocks were formed from shales, sandstones and coal deposits from rivers. During the Quaternary period, the Puget Lowland was covered by numerous ice sheets, with the most recent being the Fraser glacier with a peak of approximately 14,000 years ago. Upon the glacial retreat, the landscape was formed by glacial erosion glacial drift deposits. 3.3 Specific Subsurface Conditions The following subsurface conditions are estimated descriptions of the Project subgrade utilizing information from the depth of penetration at all testing, sampling, observed and investigated locations. Soils for this project were described utilizing the Unified Soil Classification System (USCS). Using the USCS in conjunction with estimated relative densities and other anticipated engineering properties of the soil, susceptibility for potential landslides, erosion and seismic hazards may be assessed. The Project is composed of native soils with no indications of borrowed fill. For engineering purposes,these native soils consist of distinguishable layers, as presented below. Soils within the upper 10 feet of natural ground were observed to be moist, brown poorly-graded Ens irotcch Enginccring - Gcotcchnical hip csligation Ph. 00-275-9174 pagc 5 Parccl 2212i 44 1)1000 Fax: 360-2";-4789 Mason count\. \V Ishington March 2i. 21H18 gravel with silt and sand (GP-GM). The relative densities of this soil are provided in Section 3.1 of this report. Gravels are primarily coarse, and subrounded. Sand content was primarily medium and coarse.The fines content exhibited none to low plasticity. According to the well reports and knowledge of the general area,soils below the observed 10 feet in depth are dense to very dense soils consisting mostly of sand and gravel. 3.3.1 Groundwater From the water well report, permanent groundwater is approximately 26 feet directly below the property at the building pad location. Perched groundwater at shallow depths was not observed on-site,nor indicated on the well reports. 3.4 Soils Testing The soil samples obtained at the Project site during the field investigation were preserved and transported for possible laboratory testing. Visual classification of soils was performed in the field. The following soil tests were performed in accordance with the American Standards for Testing and Materials(ASTM): 3 Visual Classifications(ASTM D2488) 3.4.1 Visual Classification The results from the visual classification are presented above in the Subsurface Conditions Section at depths of up to 10 feet below the natural ground surface. Specifically, soils within the upper 10 feet consisted of approximately 60%gravel, 30% sand-sized soils, and less than 10% silt. Minor variations observed during the visual classification of particle size content(i.e. gravel, sand, fines), or isolated pockets within the soil stratification were insignificant in relation to the overall engineering properties of the soil. Emirolcch Enginccring -- — — Gcolcchnical Imeshgalion Ph, 360-27i 9'74 page 6 Nrcc1 22'2i 44 01000 Fax: ',60-27i-478') Nbson Counlx. Washinglon N'lnl'ch 2i. 2001." 4.0 ENGINEERING ANALYSIS,CONCLUSIONS AND RECOMMENDATIONS The following sections present engineering analysis and recommendations for the proposed improvements of the Project. These recommendations have been made available based on the planned improvements as outlined in the Introduction Section of this report-,general observations including drainage and topography as recapitulated in the Surface Conditions Section; and, soil conditions that were identified from the geotechnical investigation that is summarized in the Subsurface Investigation Section. Engineering analysis and recommendations for the Project that is provided herein, includes pertinent information for building foundations, earthwork construction,slope stability/erosion control,drainage,vegetation and seismic considerations. 4.1 Building Foundation Recommendations Recommendations provided in this section account for the site development of a typical one- story, single family manufactured residential structure. Below the upper 12 inches of Project soils,there is apparently one distinguishable soil layer that will influence the bearing capacity and settlement of the structures. The recommended allowable bearing capacities and settlements as presented below, consider the probable type of construction as well as the field investigation results by implementing practical engineering judgment within published engineering standards. Evaluations include classifying site soils, and deriving probable relative densities, unit weights and angles of internal friction of the in-situ soils based on observed field conditions and soil testing for this Project. The frost penetration depth is not expected to extend beyond 6 inches below the ground surface for this Project under normal circumstances and anticipated design features. The soils on-site have low to moderate frost susceptible characteristics and should be used only to the extents P y provided in this report. 4.1.1 Bearing Capacity For the existing site conditions, bearing values should increase with depth. Existing in- situ soils for this Project indicates that the structure can be established on shallow, continuous or isolated footings. Foundations shall be established on relatively undisturbed native soil. Alternatively, foundations may be constructed on selective re- compacted native soil or compacted engineered fill as described in the Earthwork Construction Recommendations Section of this report. Footing width and depth recommendations shall be adhered to,and are based on 1500 pounds per square feet(psf) maximum structural bearing pressure. For a bearing capacity requirement of no more than 1500 psf, a minimum footing diameter (or width) of 15 inches shall be placed at a minimum of 18 inches below the existing ground surface. Foundation recommendations are made available based on adherence to the remaining recommendations that are provided in this report. 4.1.2 Settlement Total and differential settlement that a structure will undergo depends primarily on the subsurface conditions, type of structure, amount and duration of pressure exerted by the structure, reduction of pore water pressure, and in some instances, the infiltration of free EmirolccliEn� GcotcchmcalImesti anon Pli. 160-27i-9374 page 7 Parcel 44 01WO Fax: 360-OF A 17i-a789 �y� }gyp Mason Coumm. Washim lon a i c9 t ea a o A u ELV tit:11'Ch25. 21108 tF"C+il"! Mason co"i tt'p moisture. Based on the expected native soil conditions, anticipated development, and construction abides by the recommendations in this report, the assumed foundation system may undergo a maximum of 1.0 inch total settlement,and a maximum differential settlement of 0.75 inch. 4.2 Lateral Earth Pressures Lateral earth pressures exerted through the backfill of a retaining wall are dependent upon several factors including height of retained soil behind the wall, type of soil that is retained, degree of backfill compaction, slope of backfill, surcharges, hydrostatic pressures, earthquake pressures, and the direction and distance that the top of the wall moves. Significant retaining structures are not anticipated for this Project. If retaining walls are later planned for this Project, prescriptive requirements from the County should be adhered to. For retaining structures with a height exceeding County prescriptive requirements, additional design parameters must be accounted for in the retaining wall analysis, and recommendations should only be provided by a qualified engineer after the type of backfill is acquired, inclination of backfill slope is estimated, and the final wall height is determined. 4.3 Earthwork Construction Recommendations Founding material for building foundations shall consist of undisturbed native soils. Compacted engineered fill,or selective re-compacted native soils may be used to the extents provided in this Earthwork Construction Recommendations Section. The following recommendations include excavations, subgrade preparation,type of fill,and placement of fill for building foundations. 4.3.1 Excavation Excavation is recommended to remove any excessive organic content or other deleterious material, if present, beneath foundations and to achieve appropriate foundation depth. Additional sub-excavation will be required for this Project if the soils below the required foundation depth are loose,saturated,or otherwise incompetent due to inappropriate land disturbing, or excessive water trapped within foundation excavations prior to foundation construction. All soils below the bottom of the excavation shall be competent, and relatively undisturbed or properly compacted fill. If these soils are disturbed or deemed incompetent, re-compaction of these soils below the anticipated footing depth is necessary. Excavations shall be completely dewatered, compacted, and suitable before placement of additional native soil, engineered fill or structural concrete. It is suggested that foundation excavations are inspected by a geotechnical engineer or qualified professional in order to assess the bearing material prior to the placement of structural footings. 4.3.2 Placement and Compaction of Native Soils and Engineered Fill For engineered fill or disturbed native soils that will be utilized as fill material directly beneath foundations, observation and/ or geotechnical testing is recommended prior to foundation construction. The following placement and compaction requirements are necessary. For disturbed native soils or engineered fill beneath foundations, limits of compacted or 6mirotcclh F..nginccring -------------- ---- Gcolcchnical Imcsti,ation Plr. 100-27i 9374 page 8 Parccl 2212i 44 Ul(IUII F;r� ,hn-27;-178�) Mason ('onnl\. Ww'1iin<'ton March 25. 2008 re-compacted fill shall extend laterally from the bottom edge of the foundation at a rate of one foot for each foot of compacted or re-compacted fill beneath the foundation. See the illustration below. FOOTING COMPACTED NATIVE SOILS OR ENGINEERED I FILL I II UNDISTURBED SUBGRADEI Both engineered fill and native soils used as compacted fill should be free of roots and other organics, rocks over 6 inches in size, or any other deleterious matter. Engineered fill should consist of 60%to 100%gravel-sized material(particles between 3/16-inch and 3 inches),and less than 10%fines(particles passing#200 standard sieve)by weight. Compaction shall be achieved in compacted lifts not to exceed 8 inches and 12 inches for native soils and engineered fill, respectively. Each lift should be uniformly compacted to at least 95%of the modified Proctor maximum dry density (ASTM D 1557) and within 3% of optimum moisture content. Each lift surface should be adequately maintained during construction in order to achieve acceptable compaction and inter-lift bonding. 4.3.3 Retaining Wall Backfill As previously mentioned, significant retaining structures are not anticipated for this Project. However, if used, native soils may be used as retaining wall backfill for this Project. Backfill may also consist of engineered fill or borrow materials approved by a geotechnical engineer. Placement, compaction and extents of retaining wall backfill should also be specified by a geotechnical engineer or qualified professional. 4.3.4 Wet Weather Considerations Although the subsoil characteristics do not pose a great risk in regards to saturation, additional provisions may be required during prolonged wet weather. Every precaution should be made in order to prevent free moisture from saturating and ponding within excavations. If the bottom of excavations used for footing placement changes from a moist and dense characteristic as presented in this report to loose, saturated conditions, then these soils become unsuitable for foundation bearing material. if this situation occurs, a geotechnical engineer should be notified, or these soils should be completely removed and replaced with suitable compacted material as presented above. 4.4 Slope Stability and Erosion Control Landslides are natural geologic processes, and structures near slopes possess an inherent risk of adverse settlement, sliding or structural damage due to these processes. Geotechnical engineering cannot eliminate these risks for any site with sloping grades because gravity is constantly inducing strain on the sloping soil mass. Excessive wet weather and/ or earthquakes will Em irolech Engineering Geotechnical Imestig;Ilion Ph. 100-27;9174 wpc 9 Parccl 2212);44I1IWO F 1\ 0O 2 7; 4789 Mason Connl%. Washington U .a � e N ; a..- �. �00"N' exacerbate these strains. Geotechnical engineering considers excessive wet weather and `design' earthquakes in order to provide an acceptable factor of safety for developing on or near sloping terrain.These factors of safeties are based on engineering standards such as defining engineering properties of the soil,topography, water conditions, seismic acceleration and surcharges. Surface sloughing or other types of surficial slope movements usually do not affect the deep- seated structural capability of the slope. However, excessive and/or repeated surficial slope movements, if not repaired, may represent a threat to the structural integrity of the slope. With appropriate drainage and erosion control provisions for this Project during and after construction, it is unlikely that this Project will experience excessive surficial movements. However, maintenance of the slope must be completed if the situation does arise in order to prevent the possibility of further surficial or deep seated slope movements that may be damaging to life and property. According to the Resource Map from the Washington State Department of Natural Resources (DNR), the Project is within terrain labeled `highly unstable' and `highly erodible' relating to soils. However, DNR did not indicated previous landslide activity near the Project. DNR also labeled portions of this project as medium and high slope instability with relation to slopes. This delineation is primarily dependent upon slopes and convergence. Secondly, lithology and precipitation are modeled within this delineation. In summary, this designation is based on mapping without field observations or knowledge of the specific site geology or soils. The highly unstable slopes as designated by DNR do not correlate with observed site conditions. The soils are unsaturated,coarse granular materials with increasing density with depth. These soil properties are beneficial to deep slope stability. The upper porous soils are mostly medium dense to dense, overlying denser soils. These conditions exhibit shallow landslide possibilities when excessive groundwater is within the upper soils. However, these soil conditions are extremely common in this area. Furthermore, excessive groundwater within the surface soils of the critical slopes is highly unlikely due to the insignificant upland drainage basin from the slopes, and the absence of runoff loading from development. If development occurs near the top of the steep slopes,runoff should be tightlined to an area beyond the toe of the critical slopes. The Simplified Bishop Method, utilizing `STABLE' software, was used to analyze the static stability of the site slopes. Various radii's and center points of the circle were automatically selected, and produced factor of safeties in a graphical and tabular format. Worst case scenario values were used in the slope stability analysis in regards to topography, surcharges, water content, and cohesion of the site soils. STABLE software has been repeatedly checked with manual calculations, and consistently proved to be a very conservative program. The following soil properties were used in the analysis, and are based on observed conditions, known geology, and/or published parameters: Top 5 feet of weathered soils • Soil unit weight: 132 pcf • Angle of internal friction: 35 degrees • Cohesion: 0 psf Em irotedi Engineering GeolCCllnicll lm cstigation Ph. 160-275 9174 page 10 Nrccl 22'2)i 44 O1000 Fax 360-27i-4789 Mason Count.. WIsliiligloll Mardi 24;. 21008 Soils below 5 feet • Soil unit weight: 138 pcf • Angle of internal friction: 38 degrees • Cohesion: 0 psf Soils below 50 feet • Soil unit weight: 128 pef • Angle of internal friction: 20 degrees • Cohesion: 0 psf Seismic conditions were estimated utilizing worst case scenario values from the static analysis, a horizontal acceleration coefficient of at least 0.15, and applying the applicable values to slope stability charts. These stability charts were presented by the American Society of Civil Engineers (ASCE)in the"Journal of Gcotechnical and Gcoenvironmental Engineering," April 2002. Anticipated building loads, building pad cuts, or impacts from septic drainfields are not expected to have any detrimental influence on the global stability of the critical slopes, provided that the setback requirements,drainage and all other recommendations in this report are adhered to. Based on the aforementioned Project criteria, observations, slope stability analysis, and the recommendations in this report, the Project has an acceptable factor of safety of over 1.5 relative to deep-seated, static slope failures. Furthermore, an acceptable factor of safety of over 1.1 for seismic conditions was also concluded for this Project. See the slope stability information in Appendix D for input parameters and example of outputs. For this project, minimum factor of safeties for static and dynamic conditions were estimated to be 1.6 and 1.3,respectively. j Project f � r zz • --�-��� �,a.,a s ,roe rAl Map from Washington.State Department of Natural Resources Website Envirotech Engineering Gcotechnical Investigation Ph. 360-275-9374 page t I Parcel 22325 44 01000 Fax: 360 2 5-4789 Mason County. Washington Printed from' Mason County DMA March25,2008 Printed trorn Mason County DMS 4.4.1 Septic Drainfield Impacts The approximate location of the proposed septic drainfield is presented on the Site Plan in Appendix A of this report. Based on the septic drainfield location with relation to the existing and proposed topography, the drainfields are not expected to adversely influence slopes or the structures near the critical slopes. 4.4.2 Building and Footing Setbacks Provided that assumptions relating to construction occur and recommendations are followed as presented in this report,the factor of safety for slope stability is sufficient for a 50 fed building setback from the toe of the nearby ascending slopes exceeding 40%. See the Geologic Map in Appendix B for an illustration of the setbacks. 4.4.3 Temporary and Permanent Erosion Control Based on the USCS description of the Project soils, the surface soils are considered slightly erodible. This is due to the lack of silts, clay and fine sands in the surface soils, which is estimated to be less than 10%of the soil. However, this Project was designated highly erodible by DNR,and temporary and/or permanent erosion control measures may be required for site development. Extents of temporary erosion control will mostly depend on the timeliness of construction, moisture content of the soil, and amount of rainfall during construction. Soil erosion typical to the existing site conditions and planned disturbance of the Project include wind-borne silts during dry weather, and sediment transport during prolonged wet weather. Sediment transport could be from stormwater runoff or tracking off-site with construction equipment. Erosion control measures may need to be employed if excessive erosion occurs or required by the County or other prevailing agencies. Erosion control during construction should include minimizing the removal of vegetation to the least extent possible. If necessary, erosion control measures during construction may include stockpiling cleared vegetation,silt fencing, intercepting swales, berms,straw bales, plastic cover or other standard controls. Silt fencing is presented in this report as the first choice for temporary erosion control. However, mulching or other appropriate temporary erosion control may be substituted. Any erosion control should be located down-slope and beyond the limits of construction and clearing of vegetation where surface water is expected to flow. If the loss of sediments appears to be greater than expected, or erosion control measures are not functioning as needed,additional measures must be implemented immediately. See Appendix E for sketches and general notes regarding selected erosion control measures. The Site Map in Appendix A depicts the recommended locations for erosion control facilities to be installed, if necessary. Permanent erosion control may also be necessary if substantial vegetation has not been established within disturbed areas upon completion of the Project_ Temporary erosion control should remain in place until permanent erosion control has been established. Permanent erosion control may include promoting the growth of vegetation within the exposed areas by mulching, seeding or an equivalent measure. Selected recommendations for permanent erosion control are provided in Appendix E. Additional erosion control Envirotech Engineering Geotechnical Investigation Ph. 360-275-9374 page 12 Parcel 22325 44 OI(X)0 Fax: 360-2754789 Mason County, Washington March 25. 2008 measures that should be performed include routine maintenance and replacement, when necessary, of permanent erosion control,vegetation, drainage structures and/or features. Sedimentation control should be adequate when utilizing the erosion control recommendations as presented herein together with implementing appropriate erosion controls with the degree of care as expected from a licensed contractor. Erosion control information and specifications in addition to what is provided in this report may be found in the current "Stormwater Management Manual for Western Washington,"prepared by the Washington State Department of Ecology Water Quality Program. 4.4.4 Surface and Subsurface Drainage Positive drainage should be provided in the final design for all planned residential buildings. Drainage shall include sloping the ground surface, driveways and sidewalks away from the Project structures. All constructed surface and subsurface drains should be adequately maintained during the life of the structure. If drainage problems occur during or after construction, additional water mitigation will be required. This may include a combination of swales, berms, drain pipes, infiltration facilities, or outlet protection in order to divert water away from the structures. The anticipated building location is outside of the 1998 FEMA flood zone, and considerably away from the damaging path of the recent flooding that exceeded the current 100 year-24 hour event. Light grading is suggested between the building location and the northwest ascending slope in order to facilitate any runoff that may originate from the wide swale away from the planned residence.The aforementioned sloping of the ground surface from structures should be sufficient. This area should not require any tree removal due to the lack of vegetation. From a geotechnical perspective, both perimeter footing drains and roof drains are optional for the single family residence. If roof drains are not utilized, splash blocks should be placed at all downspouts. If footings are established at depths greater than 2 fed below final grade, then perimeter foiling drains are recommended, if utilized, subsurface water intercepted in the perimeter footing drains, and stormwater collected from roof drains shall be tight-lined to an appropriate infiltration area or outlet protection area located downslope and at least 10 feet from any structure. 4.4.5 Vegetation Considerations Vegetation is an excellent measure to minimize surficial slope movements and erosion on slope faces and exposed surfaces. By removing trees, the root strength is decreased over time, thereby lowering the `apparent' cohesion of the soil. Transpiration is decreased, which results in additional groundwater, increased pore water pressure and less cohesion/ friction of the soil particles. Stormwater runoff also increases, and, fewer plants will create less absorption of the force from raindrops, thereby creating the potential for erosion hazards. Vegetation shall not be removed on the face of the steep slopes or within 50 fed from the top or toe of these slopes. However, any tree deemed hazardous to life or property shall be removed. If tree removal is necessary,then stumps and roots shall remain in place,and Envirotech Engineering Geotechnical Investigation Ph. 360-275-9374 page 13 Parcel 22325 44 Ol WO Fax: 360-275-4789 Mason County. Washington March 25.2008 the underbrush and soil shall remain undisturbed as much as possible. Any disturbed soil shall be graded and re-compacted in order to restore the terrain similar to preexisting conditions and drainage patterns. See the Geologic Map in Appendix B of this report for a depiction of the vegetation buffer. 4.4.6 Off-site impacts From a geotechnical position, it is Envirotech's opinion that the adjacent properties to the proposed development should not be significantly impacted if all recommendations in this report are followed. This is based on the expected site development, existing topography, land cover, and that the recommendations presented in this report are implemented. 4.5 Seismic Considerations and Liquefaction Soils immediately below the expected foundation depth for this Project are generally Type D, corresponding to the International Building Code (IBC) soil profiles. According to the IBC, the regional seismic zone is 3 for this Project. The estimated peak ground acceleration ranges from 0.50g to 0.60g.This estimation is based on the United States Geological Survey(USGS)National Seismic Hazard Project in which there is an estimated 2% probability of exceedance within the next 50 years. There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this property is the Tacoma Fault Zone, in which is nearly 10 miles to the south of this Project. This information is based on the USGS Quaternary Fault and Fold Database for the United States. The potential for liquefaction and other earthquake induced hazards are believed to be low to moderate for this Project. This is based, in part, on the slope stability analysis utilizing seismic considerations. The potential for liquefaction is very low to moderate due to the permanent groundwater within the upper 50 feet of soils_ However, subgrade characteristics such as coarse granular material and dense to very dense characteristics greatly reduce the potential for liquefaction. Envirotech Engineering Geotechnical Investigation Ph. 360-275-9374 page 14 Parcel 22325 44 01WO Fax: 360-275-4789 Mason County.Washington March 25.2008 f 5.0 CLOSURE Based on the project information and site conditions as presented in this report, it is Envirotech's opinion that additional geotechnical studies are not required to further evaluate this Project. Due to the inherent natural variations of the soil stratification and the nature of the geotechnical subsurface exploration, there is always a possibility that soil conditions encountered during construction are different than those described in this report. Therefore, it is recommended that a qualified engineer observes and documents the construction, or Envirotech is promptly notified if project and subsurface conditions found on-site are not as presented in this report so that we can re-evaluate our recommendations. This report presents geotechnical design guidelines, and is intended only for the owner, or owners' representative,and location of project described herein.This report should not be used to dictate construction procedures or relieve the contractor of his responsibility. Any and all content of this geoteelinical report is only valid in conjunction with the compliance of all recommendations provided in this report. Semantics throughout this report such as `shall,' `should' and `recommended' imply that the correlating design and/or specifications must be adhered to in order to protect life and property. Semantics such as `suggested' or `optional' refer that the associated design or specification may or may not be performed. The recommendations provided in this report are valid for the proposed development at the issuance date of this report. Changes to the site other than the expected development, changes to ordinances or regulatory codes, or broadening of accepted geotechnical standards may affect the conclusions and recommendations of this report_ The services described in this report were prepared under the responsible charge of Michael Staten, a professional engineer with Envirotech. Michael Staten has appropriate education and experience in the field of geotechnical engineering in order to assess landslide hazards, earthquake hazards,and general soil mechanics. Please contact Michael Staten at 360-275-9374 if you have any questions, comments, or require additional information_ Sincerely, Envirotech Engineering Ag) ok- Michael Staten, P.E. Geotechnical Engineer EnOrotech Engineering Geotechnical Investigation Ph. 360-275-9374 page 15 Parcel 22325 44 01000 Fax: 360-275-4789 Mason County.Washington rin <,� k k �i,�;Jn ount March 25,2008 POnted trotn Mason County DM APPENDIX A SITE PLAN Printed from aeon Co DMS unty 1 ' SCALE, I INCH 150 FEET 520FT �e /PROPE O RTY LINE ti I APPROXIMATE LOCATD]N OF MISSIM CREEK T�2 LOCK LL LOG M, CA ION g SED SILT FENCE L ERNATIVE EROSION TROL CIF NECESSAR ) !T (Syt .� S INGLE FAMI IDENCE ROPOSED SEPT DRAINFIELD A 2 4 2f Z°° �0° fib° ♦� tit° cQ ti PROJECT/ INNER/ LOCATIOti SINGLE FAMILY RESIDENCE GEOTECHNICAL REPORT MICHAEL POLO PARCEL 22325 44 OttOW NOTES LEGEND MASON COUNTY, WASHINGTON L EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. ENGINEER, GENERAL LOCATIONS, AND ALTERNATIVES TO SILT FENCES NE FENCE MAY BE UTILIZED AS EXPLAINED IN THE GE17TECHNICAL ENVIROTECH ENGINEERING REPORT. SLOPE DIRECTIDN 74 NE HURD ROAD 2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND BELFAIR, WASHINGTON 96528 SURVEYOR. CONTOURS WERE EXTRAPOLATED FROM A PUBLIC EXISTING CONTOUR 360-275-9374 LIMAR SOURCE, H INCORPORATED AS EXPLAINED CREPOT TPt J@ TEST PIT SITE PLAN APPENDIX B GEOLOGIC MAP Plnnte' from Mason Counly DMS SCALE, 1 INCH - 150 FEET 520FT i 3` W SLOPE T P SOILS, MEDIUM DENSE GLACIAL TILL S OVERLYING DENSE TO VERY DENSE RTY LINE TILL ti APPROXIMATE LOCATION OF MISSION CREEK T�2 ELL LOG LOCH ION 44 Lz SLOPE T � 103C3 INGLE \ s \�* FAMI IDENCE �3 \ s T BUILDING ETBACK AND GETATION BUFFER OPOSED SEPT DRAINFIELD A T� v/ SLOPE T91"v PROJECT/ WIER/ LOCATIIN* SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT MICHAEL POLO PARCEL 22325 44 MOM LEGEND MASON COUNTY, WASHINGTON ENGINEER, �BUFTVUSET BACK ENVIROTECH ENGINEERING NOTES- LL CONTOURS WERE NOT PREPARED BY A LICENSED LAND SLOPE DIRECTION 7KLFA. WASHINGTON 99328 SURVEYOR. CONTOURS WERE EXTRAPOLATED FROM A PUBLIC 360-275-9374 LIDAR SOURCE, AND INCORPORATED FIELD MEASUREMENTS AS ---� EXISTDJG EXPLAINED IN THE GEOTECM TOUR REPORT. TPI TEST PIT GEOL❑GIC MAP APPENDIX C SOIL INFORMATION "Oted from Mason Count DMS VERTICAL AID HDRIZDITAL SCALE I INCH 70 FEET LOOSE TO DENSE GLACIAL TILL PROPOSED HOME EXISTING GRADE DENSE TO VERY DENSE GLACIAL TILL FT SECTION A-A PROJECT/ OWNER/ LOCATION, SINGLE FAMILY RESIDENCE GE❑TECHNICAL REPORT MICHAEL POLO PARCEL 22325 44 01000 MASON COUNTY, WASMNGTON NOTES ENGINEER ll MINOR GRADE CHANCES WILL BE COMPLETED IN ORDER ENVIROTECM ENGINEERING TO ACHIEVE POSITIVE DRAINAGE. 74 NE HURD ROAD E) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF BELFAIR, WASHINGT13N 96MB THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS. 360-275-9374 LOVER DEPTHS ARE BASED ON SITE GEOLOGY, WELL LOUS), AID)/OR EXPERIENCE IN THE GENERAL AREA SOIL PROFILE TEST NT LOG TEST PIT NUMBER TP-1 PROJECT: SFR Geoledwks!Report DATE OF LOG: 03M&2008 PROJECT NO: 0828 LOGGED BY: MCS CLIENT: Michael Polo EXCAVATOR: WA LOCATION: Pamal 22325 44 01000 DRILL RIG: Nona M..Cotnty.W8M*%ft0n ELEVATION: WA INITIAL DEPTH OF WATER WA FINAL DEPTH OF WATER: WA sT�ra�r+D�ratroN�ecr DEPTH B&# STRATA. USC8 DESCRIPTION PI DEPTH N CURVE 8AMpl.ERS AND TEST DATA 1 10 30 60 0 ... Blum.,mobL boys b rmd xn dfanss POORLY-GRADED GRAVEL wMh SILT cl and BAND.Ga v b coarse and 1 wbrotndsd.Sand b Wh arty rmdknr and ooarss.Low pb dit. Dwm 2 3 4 5 !s a Dean to Vsry Dams 7 l 8 10 Eoacardbn WWI at sppoodmsMy 10 lest No Gvrndmufur 6roouMned ENVIROTECH ENGINEERING GealechrAcmi niblrOrwb�rNibMsa�►b�Ma�dMasiaora Elk iMNprMrd�Msr��dar wi/s� Prn' :., TEST NT LOG TEST PIT NUMBER TP-2 PROJECT: SFR Geoff Repot DATE OF LOG: O 2212M PROJECT NO: Den LOGGED BY: MCS CLIENT: Mich"Polo EXCAVATOR: WA LOCATION: Par 01000 DRILL RIG: None him m may,yy , ELEVATION: WA INnIAL DEPTH OF WATER: WA FINAL DEPTH OF WATER: WA aTMONO re+Ens►na+ m DEPTH am STRATA.SAMPLERSUSCS DE$CRPTION LL Fn DEPTH N CURVE AND TEST DATA 10 30 50 Brown.nndK bm so madMan dNw POOIiL.Y41RADED GRAVEL wl h BB.T and SAID.On al b comma and 1 vAga nds&Sand k F6 rmll wM*mdad.Low pl m@*. Do a 2 8 norm gam 6a:aalbn tsminlsd at approodmMMy 4 S.5 fsd 5 6 7 8 e 110 No vrasbwaiw Enoardwad ENVIROTECH ENGINEERING nfrrww.ra.v«w�.oneawreo .pe.naa�oea. 1° +0 a A ,F I dn6ftiidaal�dMpisair TEST RT LOG TEST PIT NUMBER TP-3 PROJECT: SFR GooMdw*W Report DATE OF LOG: M12?J = PROJECT NO: OM LOGGED BY: ARCS CUBIT. Mid"Pob EXCAVATOR: WA LOCATION: Parcel 22;i25 4401000 DRILL RIG: Now Mason co,My,wadlirow ELEVATION: WA INITIAL DEPTH OF WATER WA FINAL DEPTH OF WATER: WA sT/1I Mw Pw&MwTM Tw DEPTH SM STRATA, USCS DESCRPTION LL Pl DEPTH N CURVE SAMPLER$ AND TEST DATA I 1 10 30 50 0 ....... ... ..........I......... ... Brawn,molK loose to median dansa POORLY-LADED GRAVEL wNh SILT and SAND.Gram Is moody coons and 1 o Do s&off dod Bard is p i mroy wavadad Pod*at Ans Qard.Law PAY• 2 DdMs 3 EiocNatlorr Mmiralad at appnoodrrnloy 4 3.5 W 6 Q 7 8 9 10 No Grorsdwalor Enooustered ENVIROTECH ENGINEERING nrs�s�awraYbN�boii�aAdalioi�fnora Oaoledrioai Epp iullllM�id M 6UO lr�rr dM ass a� WATER WELL REPORT CURRENT 2'a owner,3"co drilkr Notice of Intent No. W 249616 .,I original&1 copy-Ecolop, copy- PY- Construction/Decommission ("x"in circle) Unique Ecology Well ID Tag No. 7Aga18111611 1� 1012 .O Construction Water Right Permit No. O Decommission ORIGINAL INSTALLATION Notice Property Owner Name_Michael Polo oflntent Number Well Street Address Steelhead Dr. PROPOSED USE: llkmmesric ❑ Industrial ❑ Municipal City Belfai r County Mason— Q DeWater ❑ Irrigation ❑ Test Well ❑ Other Location_ /4-1/4 SE I/4 Sec 25 Twn 23 R 24J Ewm drde TYPE OF WORK: Owner's number of well(if more than one) wwr t 01e [XNew well ❑ Reconditioned Method.❑ CD able o Ronny o JettedLat/Long(s,t,r Lat Deg Lat Min/See ❑ Deepened DIMENSIONS: Diameterofwell o inches,drilled 57 R Still REQUIRED) Long Deg Long Min/See Depth of completed well 57 R CONSTRUCTION DETAIIS Tax Parcel No. - Casing IkWelded Diem from fl.to ft. Installed: ❑ Liner installed Diam from ft.to fL CONSTRUCTION OR DECOMMISSION PROCEDURE ❑ Threaded Diam from ft.to R Perfontdons: ❑ YesNa Formation: Describe by color,character,size of matetid and structure.and the kind and name of the material in each stratum penetrated,with at least one entry for each change of Type of perforator used_ information. USE ADDITIONAL SHEETS IF NECESSARY. SIZE of perfs in by in.and no.of perfs_f um R to ft. MATERIAL FROM TO Screens: I;t Yes ❑ No I? K-Pac Location 55 Manufacturer's Name Tc hnS^; - gravel 0 3 Type Model No. Diam- S of size _from�_R to �_R. Di.m. SI«siu from R to R BrOtslrl till 3 19 Grovei/Fllter packed: ❑ Yes ❑ No ❑ Siu of gmveVsand Materials placed from ft.to ft. Brown saW & gravel Surface Seal: Ej Yes ❑ No To what depth? 1 R R Material used in seal E�ef-oni f-a Sarid & cfravel With water 26 Did any strata contain unusable water? ❑ Yes [A No Type of water? Depth of shata Method of sealing strata off PUMP: Manufacturer's Name Type: H.P. WATER LEVELS: Land-surface elevation above mean sea level_ft Static level 26 ft.below top of well Date Artesian pressure lbs.per square inch Date Artesian water is controlled by (cap,valve etc. WELL TESTS: Drawdown is amount water level is lowered below static level Was a pump test made? ❑ Yes (A No If yes,by whom? Yield: JO./min with ft,drawdown after hrs. Yield: gWJmin with ft.drawdown after hrs. Yield: galJrri with ft.drawdown after__ hrs. Recovery data(time taken as zero when pump ruined oln(water level measured from well top to water level) Time Water Level Time Water Level Time Water Level Date of test Bailer test j4d./min with 1 R drawdown after_1_hrs. Airiest gafJmin.with stem set at ft.for hrs. Artesian flow 0p m Date Temperature of water Was a chanical analysis made? ❑ Yes M No Start Date 1/12/{)8 Completed Date WELL CONSTRUCTION CERTIFICATION: I constructed and/or accept responsibility for construction of this well,and its compliance with all Washington well construction standards. Materials used and the information reported above are true to my best knowledge and belief. Q*hller ❑Engineer ❑Trainee Namre rint)_� K�n Drilling Company Dayi--, Dri l linQ Drilla/EngirneedrrainccSignature I 0A w — -�^ Address 340 NE Davis Farm End Driller or trainee License No. 1706 City,State,Zip Belfa.ir, WA 98528 If TRAINEE, Contractor's Driller's Licensed No. Registration No. DAVISDI1 1 00A Date .Ian. 08 Driller's Signature Ecology is an Equal Opport ruty Employer. U 1 A.;uno---- uose.A woij pc-,,,,iuijcj s N cil AllrHgVJLS MO IS G3aaN3aav STABLE Slope Stability Analysis System New User Project : Polo Datafile: Static Bishop 10 11 3 11 12 3 +++tx++++tt+++++tt++a+xt+at++ttt+ttt++ttt+x+tttt+a+that+t SOILS SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT. 1 upper CONTINUOUS-BLACK 0.00 35.0 132.000 2 lower CONTINUOUS-BLUE 0.00 38.0 138.000 3 Soil-3 CONTINUOUS-BROWN 0.00 20.0 128.000 +xxxat+xtttxxttx+ttx+x++rtxt+++ttt++ttt+++tt+x+++ta+tt+txt PORE PRESSURE SPECIFICATION SOIL PIEZO RU EXCESS Y/N/P Value Value 1 N 0.000 0.000 2 N 0.000 0.000 3 N 0.000 0.000 PIEZOMETRIC SURFACE POINT POINT PORE PRESSURES POINT PRESSURE xt+t+tta++tt+attxt++t+xt+a+xt+xa+++txtaaxxaara+a++atttx+ar SLIP DIRECTION (+/- X) x+t+aa++x+a+a+tt++t+ax+x++atx+rtarattarr+at+tt++trot+++ar SLIP-CIRCLES AUTOMATIC Circle Centre Grid Extremities 262.200 t++++ttat+tt++x r 26.400 + a 237.600 + + +ta+a+t++taaa+t 51.000 X spacing -- no. of cols (max 10)= 10 Y spacing -- no. of rows (max 20)= 20 Grid 1 Circles through point 13 Grid 2 Circles through point 14 Grid 3 Circles through point 15 Grid 4 Circles through point 16 00000000000 w\ 0 J 0•_ i1 - w LL 1 0 0 N U— �o v- >NO --- Q -w 041 Q L 0 Cm aQQQ Tinted from Mason County DM Printed from Mason County DMS f 1 ,0 c0T 1 (e)w 8 ' a a 45 —p-2 a —p=2 00, Y Q Po �6 3D 9 6 6 F Q t" 30 4 • 4 IS _—r kM 0 1 z ki=0.2 2 Ail=0.3 F-I.btu 3 � 0 -- ° 0 05 t 7 5 2 tb O 05 t 15 2 2 5 0 0 5 1 13 2 25 4 (d) 4 v (b) 9 = 1.47 2 � 2 taa� �OI K�sCtl F- b' O ka=0.140 k�=0.2 kh=0.3 ° 0.1 02 0.3 0.4 taS at nz ta3 a0 a5 °0 0.1 02 c 0.3 0.4 0-5 r Fig.4. Safety factor for slopes subjected to quasi-static horizontal force sideted to be fully drained where dilation of the soil skeleton does snake it possible to make an"educated guess"of the influence of not cause any change in the magnitude of the pore water pressure. pore water pressure an the stability of slopes. For die purpose of presenting the influence of the pone water on the stability of slopes,the distribution of the pore water pres- Quasi-Static Saismic Eflisct sure is described by coefficient r„ defined by Bishop and Mor- genstem(1960)as Seismic loads on slopes are often considered in design by includ- e ing quasi-static forces due to seismic acceleration.While such an ry=�h (8) analysis ignores the seismic process (acceleration history) and does not give any insight into the behavior of the stroctnre,it is where u=magnitude of the pore water pressum y—soil unit routinely used in design.The kinematic approach of limit analysis weight,and h—depth of the point on the failure surface below the was used here to arrive at the data used to ptvduce the charts in slope surface. Stability charts for slopes with r„equal to 0,0.25, Fig.4.Coefficient kh represents the intensity of horizontal accel- and 0.50 are presented in Fig. 3.The data in the charts in Fig. 3 erstion as a fraction of the gravity acceleration. The effect of was created using a computer program written earlier (Michs- quasi-stoic forces was inchided in the analysis as an additional lowaki 1995). work on in the energy balance equation(Micbalowski 1998). Coefficient rr is a rather crude manner of accounting for the No pore water pressure was considered in calculations with a pore water pressure in a slope. If a well-defined flow net in a quasi-static seismic force. The quasi-static approach is a crude slope is known, the corresponding pore pressure distribution can approximation of seismic effects, and charts involving another be calculated and included explicitly in computations of the sta- simplified concept(r„)to describe the pone water pressure disW- bility number(or the safety factor). While such calculations are bution,in addition to kh,may not be indicative of the true safety more accurate,presentation of the results in charts would be dif- margin of slopes. Such charts would be an inappropriate tool for ficult because of the large number of variables needed to describe analyzing the safety of slopes,particularly for liquefiable soils. realistic flow nets. While the nature of calculations with pore Safety factor F, represented in the charts as F/tan q), is an pressures described in Eq. (8) is rather approximate, the results increasing function of NO (or a/yH tan cp)up to some threshold 3541 JOURNAL OF GEOTECHNI(.AL AND GEOEWIRONiENTAL ENGINEERING/APRIL 2002 APPENDIX E EROSION CONTROL lnted from MaSlon County DMS j -,! r -10NIN03 N❑IS❑d3 '133f 021d 3H1 30 S1INIl 9NIHV3M 3H1 WO&I 3dOl04AM a31V3Ol Ml llwm S33113! ITS 'L '33N33 ITS 3/1 NOMJ 3Cl3I& l QNV S1SOd tLE6-SL2-O9E all j0 3NII 3Hl omyN 133HS SIHl ND S1Ivim 3HI Dl 9NIQM033V mmv3X3 3H 1-miS HON3al v '9 Q2Q96 N019NI4SVA WV1131 -a3Sfl SI ONI3vdS 1SW MOM Qill 'UN3MVlIIGNOi) DIMBV! M311I! HIDNM1S-VaIX3 av(m a" 3N tL !I Q31VND(II3 38 AVw HS3w 381A 3i1 '1N311AIM3 aO 39fM ►IX.ZX Z 311 Tr" H33f MIA 'z ONIH33KM3 H3310MIAN3 'QNfl M 3H1 DIM AI3MMM N3AIaa Q03MN3 CM '133HS SIHl NO S1IV13a 3H1 Ni Q31V3laNI SHLd3Q IV a33Vld aNV a33VdS 39 TWHS SISUd 't 'OM3VdS NOlOMHSVA 'A1NIO3 NOSVw NI t i (SONIa DOH) S3MIA 3I1 M S3'1dV1S .1 9MSn Q3N31SVj 38 IIVHS 3IMHV! M3111! abv"IS 'E ISOd 3H1 01 SaN3 HIM OOOIO tip Qn22 133Wd IV a3N3ISVj A13M033S QNV dVIM3A0 HW-9 Nf1NINIw V HIIA ISM ISDddf1S V IV A7NO M3H13WI Omd 'G*alw (r3D11d3 39 IIVHS 31SHVJ 83111j 'AMVSS333N 3dV SLNIDf !I 'S1NIa' Ja 3Sfl aIOAV 01 a3laM H3V3 iKd38 -lV3INH03103D 30 HION31 311 Ol !fq 110M SnOnN lN133 V NI Q3SM13WW 341 TM4S 3IMHV! M311I! 31L1 1339 '2 SQWaM/1S AlNIO3 3I1V3IlddV MO :NISVH aWGS I390d 3HI a0j 33N3aIS38 k-lIWVJ 31DNIS -iwmw 1N3w3!)Yh w a3LVAwMDIS. 3l1 M a3lJM3dS Mad 3H IIVHS 3dAI 3IaeV! WITJ 3111X31M I NOlIV30I /M3NAO /133f'0)Id 33N3j ITS 'I 83DOALIN AS a3a3AO3 39 IIVHS HDVW DNIMIfI03a SV3aV 'a3ZI-IIIVIS 80 931331Uad A131VIadD8,kN g T1V NOSv3S 3Hl j0 3SRv33Q Q3Q33S 38 1DINV3 H3IHA SV39V N33S SVH V3av QNVI Q3 CUN3i13a01y SY 31al V 143M TIM 3SV33 AI3LVla3ww1 E€ NI W DNIQ33S 831JV Al3iV1a3w1a a3Sfl 39 aVOHS ONNOTM '£ 7wm 'AIIAlIDV IOlIIN03 IN3wIQ3S ON NMS093 (13AD8&N SM 1433X3 '3IIS 3u (ly3llM3hlv1NOZI2011) PZ NVHl a31V321`I S3dois NO AlIAIl3v NOInnaiSNOD Tlv 'a3vv313 N331 9NU\VH a31jv SAVQ r a3IIV1VIS a3SOdX3 H1IA SV3aV IIV NI Q3IIddV 38 aTMS HTYM 2 AI31V18dOaacN N336 ION SVH SO a313310a&M SMVw3M Q3)Qi A A13AII3v DNI31 '3WV aid saW)Dd ION V38V QNVI ANY LVHl IN3A3 3HI M 'S3AI3Sw314l JO QNV NI M3AO3 3.LW03QV 0001 AD 31V8 V 1V a3llddV 38 a-n]HS 0MV '3SD'vnl33 a3HI! SV MAMA 31 ION TQA "313 'SQNOd 1N3w ais 'sj"i 1N3wIQ3S 'DN13N3! nis awA 3H Ol 03QN3www3a 3W 9N1H3VMi a0! a3Sf1 SIVIa3LVw I •a3Xam Al3Ali3v DNI31 IDN !I 031af11SIa 3SIAa3H1!] a0 a3W3I3 N339 DNIAVH a31lV SAW C ND411A 'M3 'lvla3LVM DMMVaa 33MI 'S13*Wl1 NMSOM3 '9NII33HS 9MH3VMf 311SV1d 'OM113N '9NI43VMf SV H3f1S 13ZIIIIVIS 3SIA93HID 38 a0 M3AOD 3AII33LIald 31VIIldMkWV 3AT3338 IIVHS SV30Y a3Hiil1SIQ 80 a3W313 TIV (SN3d3a wflllO!]al) 06 '03AM3S90 SI 3IIS-i!0 laOdSNVal 96 OI a3A013 HUM 311M IN3NIa3S ON NMSOM3 M0 /QNv a31DIQ3ad SI WHOiS MD-VW V 1N3A3 all (13XD1 'AOQVHS '83NNVH 'NAOIS3WYf) NI SHWH 1,2 NDl11A Q32ITEVIS 80 all3AOD 31 NV3 SV V38V 9M1"1 HDf11 SV Ol (VIvir"c3 VaHfla vDf11S33) a311(I1 3H IIVHS 'a3AO3 aNf10ZD a3HID aNV NOIIVL393A 9NIISIX3 !0 IVAOKM 08 3HI OWarYMN1 'a"vl JO DMW313 3H1 'SS3H9Oad M SI AIIAILN HM13MISNM L6 Ot 3rtS3j %GA3i3 a3ldfla31N14fl 3M3HA S31IS NO -- (OE lr" flaHI I WMD13M NOSV3S L3A 06 86 Ot (W)WI.11ITM NIII10l) 3AM lV(NJNV 'S3I1III3V! IEaIN03 1N3MQ3S NV NOISOA3 I-II JO alVd3a dWV 33NVN3iNIVN 3H1 06 a0! 3IIISNOdS321 31 IIVHS Wj:)VMINOD /M3NAO 311 X13A Aa3A3 33M 1SV31 26 OI (WIV SUS08M d0laMf Iv QNV 'SIN3A3 MIDIS acu m Al3ivIa3wwl S3111I13V! IDaimm 1N3wm3S aNV HOISOM3 TT/ 30 NM.L33dSM 3H1 MO! TWSNOMM 31 INKS MO13VM1IO3/a3NA0 W 3HI 'SAVa 3AILf133SN13 t LSV31 1V ]A! G"IINODSM 38V SMILN 13V Cp (X) 1H013A A8 3NVN 1N311d0I3A3a 311S 83HL0 aD S3111AIIDV NO113nHISHO3 1VH1 IN3A3 3HI NI NOIIVNDWR139 Ikilw d SNOUaOdOad '0E a3Hw31d3S NVHl M31V`l ON A8 a3TIVISM 39 isnm "313 'S13)INVIH NMSOM3 'D4I1331S 3ILSVId '3Wf11XIw a33S 31VM31IV a3ADMdd4 AlW03 V W 'MHINOD '9NII13N ''?lIH3VIN SV KM 10A03 DYOM9 !O QOHI3N 3AILVNU31-IV NV '3'IHISSDd NOISMS WJ 3ani)Tw a33S Q3aN3 MM3a 9MAO110! 3HI 3Sfl ION SI N3I1vZ1-O8V1S IN3NVa3d 1VH1 "3 all M 'H1AOM0 AaCl3VjSI1VS 01 3Al3rWM 3MV SI MiM O3 1v1N3MaIAN3 311 aNV LN3NIwM SI 133'OMd 3H1 30 'SQNVl13A aW S31ME a31VA 01 IN33Vf QV N0113-kMO 1V3ISOW N3HA MOO 38 IIIA I a1=130 8313V OMQ33S I M310L30 ATI4I33dS3 'a3ZDiIND4 38 MOlS SLWONV ` MIV`aN3NNDD3M D1 SI ISfI'XIV aW '91 AVN 01 t H3aVw QQOIa3d 9NIAOI10j 3HI DWI JM Q3 WJM3d .SM3IIddf1S Ol 9NIQMODDV a3S0 39 01 3aV SM3ZIIIIM3! '9 3H 1lvHS SV3av Q3ffmiSIa 3SIAa3l10 W a3W313 j0 9MH3VW am 9MZI'111M3! '(9Ma3AO3 3USVld W313 '!VW 31rr 'STUIX31039 '9NIQ33S 'kiWC3 3Hl A8 MOMddV 3SIAa3LL0 SS3-W 'NOI13V 30 NVId "&a) 'AWSS333N 39 TUA Q3H a33S 3H1 JO 9MM4dy ([3ADMddv 3H1 Mad a3MS W OE M3Hw31d3S AH "313 '1Y1a3111w 9NDWW 3MU 'OE lladv aNV I IDIN3AON NMAL31 a31NVld Sam a33S 'S 'SL3XNvl8 NDISOM3 TNI133HS 3USV ld 'ONUAN 'DNIH31fMl !O 3SQ 3Hl H9fOM I •3WU3f1a1S LOOa 3H1 13310Md aW M31SOj a3ZIV1YIS A131V1adOMddv 39 isnw a31Mf11SIa 3SIAa3H1D 80 a3av313 Sv3bv Ol AWSS333N SV 33NYN31NIVW M3H10 aNV NOUVORMI 3If1D3a Ilv 'Nvld 1DMw4M IN3MQ3S QNV MUSOM3 3HI M Q3UMUS Sl NDIIIRIIIIWIS IlU\ IC a3fal30 aw I kvw N32A M a31NVld SQ3H 033S 't 3LVla3Wl SS3-W 'MV3A N3AM V AD OE b39W31d3S NVHl M31v1 ON A8 '3a3v Mad SQNfIOd 021 JO 31" 3H1 IV a3IlddV a3lWUSIQ 3SIAa3HIO aO Q3W3-M N338 9NIAVH 831jv 'Q3ZIlIHV1S 3SIAM34M 31 dTWS aW 'AD-GE MAOHS SV 'SMMiYaN3WNM3a 9iaa33S 'E 38 MO a3A0D 3AU33LOMd 31VIadDbddV 3AIM38 NV3 SV aNVI H3f111 SV AINO '3d0IS 3H1 01 MVY131aN3da3d NO SSad33V Ol a31INIl 3H 1Sflw %3AOD aWUd9 83UO MO NOUVIM3A 9N11SIX3 AD IVAMM SNMiVM3dO llv wW-4b3d Toa< 33VS&IS 9NIAO1l0! :*U 9MQfl'1DNI 'aNV-1 j0 9MW31D all -- ME M36WMd3S flaHl T AVw) NOSV3S AM '33VlaM 3NI! i-wvj HUA waij 38 1'IIMS a3H a33S 3HI 2 'SNISVH IN31aa3S aNv S830V38dS 13A31 'S31VAS 'iN3HIW M1 a3A0addV a3H10 M4 'S3Ma a01d3DM3LM 'S33VSM31 1N3IQVa9 SV H3f1S S3WSV3M %dil3N 'DMHO-M HIJA aMN3N9f1V 36 OS1V ISM Lf18 'a013VMINO3/M3NA0 3H1 1QI11NM I-Wk! 30Vlaf1S a3a33N T IV1SNI 'oNia33S 3MDl39 '1 j0 1SWUNI 3HI NI SI 11 93A3N3HA a333Dad AVw ONIQ33S '63A3AOl 'M38w31d3S H9fOMH1 -U&M 37 SH1NOi all 9MaM 31dV1d333V 31 AIO ILIA 3NO1V S3d0IS AVa 111! 9Wa33S 9Ma33S SSV119 21VU M 3MT1 3H1 Ol 31HV3rWdV IN3M1V3al IMINDO NOISOW a3AOUdV a3iL0 ao 9MINVId SSVa9 '9NIH3lflw H1IA 03ZIMOV1S A'131Vla3 HI 'SWM 9E 30 aMa3d V ND-WA Q33Vld aNV 3H 1S(MI Sv3W amm1SIQ my 'AOl3H VRf3LIMD a3LSIl 3HL 9NN333X3 dMI13d Q3M3AI13Q 'Q31S3ANVH 32 TIVHS STWAS SSVM MA aDS 't V Wj a3lvdl3ILNV Si )RIDA 83Hlafl! a 3M3HA aNV 'S3I11AI13V OW97inISIa 111A1AbnS Sil 133!!V kl3SS3AaV AVw IN31t= aNVI 933N3Ia3dX3 ]O MMV1393A 10 a3ddRUS N338 3AVH HDIHA SV3aV TIV WJ 3WUSM 13A a0 AMa AI3AISS33X3 N3HA Q31MIcO VM1 MO G31S3AHM 39 ION IIVHS S31VAS SSM M0! QOS 'E S31O1 IOMINO3 NMSOM3 AWMOdi31 '1OI133S lOOJ E V j0 QN3 3H1 Al a3aN3d= N3►Pk 3dVHS QNV 3IIS &3H1 •13ZIIICVIS Al1N3IVMM3d N339 3AVH SV3MV 3dOISdfl 3H1 IIIWI 33VId MV13M aw 1HD13A NAO MI311 1MOddf1S Ol H9fiW3 OHMS 38 M 1131 38 IIVHS S33IA3a aNV S3Ul-U3V! MdIMO3 iN3MQ3S aNV MMSOM3 IIV 'E 1-1VHS S3IVAS SSVM a0! ((OS 30 SNOI133S MIS QaVQNViS '2 'AWSS373N !I 'aiNivitaw Al31vla3wia aNV AIIVQ Q31334S14 'HD111H1 38 INNS S30U\3a aW S3IIMOV! IEW1NO3 1N3wIQ3S QNV NOISOM3 IN 2 aNV HIAOa9 d01 3Mn'13X3 IIVHS SS3NN3IHi a0! S1N3N3af1SV3a 'S311110V! IONINDO LNwa.3S aW NOISDM3 lvNOIllaav IIVISNI TIVHS '9MMfi7 M 3wI1 3i1 IV SS3NXDIHI IW -4MNn HOM-t/E a013VMLN03 311 'NMIO MISNDD 9Nllila 31Vfla3QVM 31 M 3ADad VN MS v IV Ira 3NIHOW 39 IIVHS STWAS SSVM MO! MIS I ND NAOHS SMMV34 -MLNM INWa3S QNv MlIS083 AdVMdN31 3H1 aVM34 I LN3W33Vld aOS -S31W IV33V39 -S310N IOa1NO3 NOISOa3 LN3NVWJU TIN r11r o SIF 3l1IMIMS � S1N31X3 W1108 l3AVa9 a3HSVA alk .aA I O1 A/C MUMS aNrKM '� noel a31vn 1 HLIA ail HDN3M1 9NI1SD0 j0 N3I.L33MIa MIA .8 'd33Q .21 1!� f l3AVM9 03HSVA a 3DVlaf1S MOM a/i i al .t/E H1IA Q311I! DNI1SDf3 a3113H f103 iIW GM a0 1N31VAI HDN3Ml MIA A 'd33a —'I9 w 1SOd a" .Sx.dx.2 I3AYa9 ONID11ld 3MA39 '3'0 'XVw 1! 9 i 3alLN3H3N3IISV3l�1VV 01 MIA QNY M3113H 80 1NTWAIf103 MH3N3M1 aWIRF4 dVMA HS3N DIMHI! 3 MIA aw (dAl) 1SDd QOOA .Zx.2 3PAtVj 3111X31039