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HomeMy WebLinkAboutGeologic Assessment Report for BLD2004-01845 - BLD Engineering / Geo-tech Reports - 3/23/2005 A UOC MASON COUNTY S H PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER NY Shelton,Washington 98584 DATE: March 23`d, 2005 INTER-DEPARTMENTAL COMMUNICATIONS TO: r M'>> , CD - Planner FROM: Alan A. Tahja, P/W- Co. Hydr. Engr. WO#PLG-05 SUBJ: Geo-Tech Submittal Review NAME: Spires-Gray SFR n Steelhead Drive BLD2004-01845 Grace, The geotechnical assessment prepared for the proposed Maryann Spires&John Gray Single Family Residence (SFR)to be constructed at 61 Steelhead Drive North, Belfair, has been received and reviewed by Public Works. Tidemark case notes were also reviewed. The case notes indicate that a geotechnical report was requested by Planning from the applicant. The assessment reviewed indicates slopes within 300 feet of the proposed activity that are in excess of 40% with more than 10 feet of relief. Under the County's Resource Ordinance, this site is classified as a Category"A"area, requiring a geotechnical report to be prepared. Mason County's Resource Ordinance provides for relief from geotechnical reporting requirements for Category"C"& "D" sites, by way of a waiver approved by the Director, but category"A"& Category`B"sites are required to have a geotechnical report prepared. Though I feel the assessment could be acceptable, I do not have the authority to relieve the applicant from the County's geotechnical reporting g be returned to the applicant/engineer for completion ro e f required�g geotechnical chni al reporting l the nelements.ol Please feel free to contact me at County extension 461 if,you have any questions regarding these comments, or if you feel any features need further discussion or attention. Sincerely, �L7'_. Tahj File: H:\WP\GEO\Undetermined\Morris.doc REPORT GEOLOGIC ASSESSMENT PROPOSED SINGLE-FAMILY RESIDENCE 61 STEELHEAD DRIVE NORTH BELFAIR, WASHINGTON MARCH 11, 2005 l FOR MARYANN SPIRES, C/O JOHN GRAY I \� \ 1\ Geologic Assessment File No. 11951-001-00 March 11 , 2005 Prepared for: Maryann Spires 6418 Pullman Place SW Port Orchard, Washington 98367 Attention: John Gray Prepared by: GeoEngineers, Inc. 2401 Bristol Court Olympia, Washington 98502 (360) 754-4240 cf Washl�r GeoEngi ers, Inc. y �� r ins Gob& ' 2522 'Sg Eric L. Smith, LG, LEG Senior Engineering Geologist 1 L. 17 Jon W. Koloski, LG, LEG Principal ELS:JWK:jm:tt TACO:\11\11951001\00\Finals\1195100100R.doc Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. File No.11951-001-00 TABLE OF CONTENTS Page No. PROJECT UNDERSTANDING AND SITE DESCRIPTION..........................................................................1 PURPOSEAND SCOPE OF SERVICES .....................................................................................................1 LITERATUREREVIEW.......................................................................................................................2 Groundwater..............................................................................................................................3 Depthto Dense Competent Soil................................................................................................3 SlopeStability............................................................................................................................3 BUFFERS............................................................................................................................................4 CONCLUSIONSAND RECOMMENDATIONS.............................................................................................4 LIMITATIONS................................................................................................................................................5 List of Figures Figure 1. Vicinity Map Figure 2. Soil Survey Map APPENDIX APPENDIX A—REPORT LIMITATIONS AND GUIDELINES FOR USE ........................................A-1...A-3 File No.11951-001-00 Page i GWENGINEERS� March 11,2005 REPORT GEOLOGIC ASSESSMENT PROPOSED SINGLE-FAMILY RESIDENCE 61 STEELHEAD DRIVE NORTH BELFAIR, WASHINGTON FOR MARYANN SPIRES C/O JOHN GRAY PROJECT UNDERSTANDING AND SITE DESCRIPTION We are pleased to present this geologic assessment in support of design and construction of a new single- family residence at 61 Steelhead Drive North in Belfair, Washington. It is our understanding that two parcels, known as Parcel Numbers 223255006010 and 223255006011, respectively, will be combined into one parcel under the address 61 Steelhead Drive North. A Vicinity Map of the project area is included as Figure 1. We received authorization for our study on January 13, 2005. Our understanding of this project is based on discussions with you, review of a County correspondence to you dated December 8, 2004, a site reconnaissance with Mr. John Gray on February 2, 2005 and our experience in the area. The project site is located in the Mission Creek Valley area in a forested upland area west of Hood Canal and south of Belfair in Mason County. The subject parcels are located on the west side of Steelhead Drive North, north of its intersection with Steelhead Drive South. The eastern portion of the property is relatively level and is currently occupied by a mobile home, a RV trailer and a small shed. West of the level area, a relatively steep wooded slope ascends about 120 feet in elevation to a wooded plateau area to the west. The wooded slope inclination varies from about 34 degrees to 37 degrees from horizontal, i.e., about 67 percent to 78 percent. Based on site reconnaissance, the upper 1/3 of the slope extends off site to the west of the subject study area. The building pad slopes down gently east toward Steelhead Drive North. The existing (and proposed) building pad area has been created partially by past grading activity. Minor cutting at the toe of the ascending slope is evident by a slight steepening at the toe and less dense vegetation. Minor filling — about 3 to 5 feet maximum thickness — has occurred at the outboard (southeast) margins of the pad area. Topographic considerations and the presence of two large-diameter trees (one Douglas fir and one big leaf maple) in the area of the proposed residential building indicate the proposed building area is primarily in cut or at natural grade. The subject property is bordered on the west by undeveloped timbered property, on the south by a developed residential property, on the north by an undeveloped residential property (currently occupied by a trailer)and on the east by Steelhead Drive North. An existing septic system has recently been installed in the southern portion of the level building area. Review and design of this system was beyond the scope of our evaluation. PURPOSE AND SCOPE OF SERVICES The purpose of our services is to evaluate surface soil and groundwater conditions at the site as a basis for providing geologic/geotechnical engineering recommendations for the proposed residence. Specifically, the services provided by GeoEngineers,Inc. included the following: File No.11951-001-00 Page l GWENGINEERS� March 11,2005 1. Reviewing selected published geologic and soil maps in our library. 2. Performing a site reconnaissance to observe surface conditions about the property and in the area of the proposed development. 3. Preparing a brief written summary of our findings and opinions regarding soils and slope conditions at the site and in the area of the proposed development. LITERATURE REVIEW According to a published geologic map of the site area, the subject property is underlain by glacial deposits of advance outwash and till. The advance outwash deposits generally consist of gravels and coarse sands beneath a Vashon till cap, and are generally in a dense condition. These deposits appear to underlie the proposed building pad area. Deposits of the Vashon till reportedly cap the upland to the west of the subject property and partially underlie the upper part of the slope to the west of the subject building pad area. These deposits generally consist of a compact and unsorted mixture of cobbles and pebbles in a binder of silt and clay deposited directly by ice(Garling,et al., 1965). Based on review of geologic maps in our files and our observation of outcrops on and in the immediate vicinity of the site, Vashon advance outwash sand and gravel is the dominant, near surface, geologic material in the immediate project area. This material was deposited by meltwater streams in front of the glacier during its latest advance in the Puget Sound region. The deposits were subsequently overridden by the advancing ice approximately 10,000 to 15,000 years ago, resulting in a generally dense (compact) deposit. Till deposits are mapped to the west, underlying a portion of the westerly ascending slope. These deposits are generally very dense to hard,locally referred to as"hardpan." The map of Relative Slope Stability of the Southern Hood Canal Area, Washington (Smith and Carson, 1977), maps the subject property as being in close proximity to the dividing line between "Class 2" and "Class 3"of relative slope stability. Class 2 areas are described as: "Areas believed to be stable under normal conditions, but may become unstable if disturbed by man's activities, if slope is oversteepened by erosion, or if subjected to strong seismic shaking. Slopes generally steeper that 15 percent, but may be less in some areas or weak geologic materials. Includes areas underlain by: well-drained sand and gravel, mostly on valley sides that lack known slope failures;glacial till with steep slopes; and bedrock" Class 3 areas are described as: "Areas inferred to be unstable because slopes, generally greater than 15 percent, are underlain by weak, unstable materials in which old or recently active landslides have occurred. Includes areas of sand and gravel on top of impermeable silt and clay, mostly along steep valley sides." The site is beyond the mapped limits of: the Coastal Zone Atlas (DNR, 1980),the Slope Stability Map of North-Central Mason County (Carson, 1975), and the Geologic Map of North Central Mason County (Carson, 1976). A soil survey of Mason County, Washington by the United States Department of Agriculture (USDA) Soil Conservation Service (SCS) maps the site as being underlain by Everett gravelly sandy loam, 0 to 5 percent slopes, with Everett gravelly sandy loam, 15 to 30 percent slopes mapped as underlying the slope to the west of the building pad area (Figure 2). The Everett soils reportedly are somewhat excessively drained, developed in assorted glacial till and outwash material, and consist primarily of File No.11951-001-00 Page 2 G MENG I N EE R5 March 11,2005 gravelly sandy loam or gravelly loamy sand. The Everett soils mapped as 0 to 5 percent slopes generally occur on smoother outwash terraces. The Everett soils mapped as 15 to 30 percent slopes also include areas having slopes slightly greater than 30 percent, such as the slope present at the subject site. The substratum is reportedly locally compact and weakly cemented(USDA, 1960). Groundwater We did not observe standing water or signs of shallow perched groundwater on the building pad during our visit. We did not observe evidence of springs or seeps on the westerly ascending slope to the west of the building pad during our traverse of this slope. We did observe evidence of groundwater seepage on portions of the westerly ascending slope on off-site properties to the north and south of the subject property. Observations along the top of the westerly ascending slope, west of the subject building pad area,did not reveal ponds or other standing water in the immediate vicinity of the slope crest. We expect that groundwater will occur at and slightly above the stream bed of Mission Creek, located east of the subject site and approximately 20 to 30 feet lower in elevation than the existing building pad. Groundwater elevations are expected to fluctuate seasonally. Depth to Dense Competent Soil Based on our site reconnaissance, topographic considerations and experience in the area, we anticipate that native advance outwash deposits will be encountered at shallow depths (about 1 to 3 feet) in the proposed building pad area. Observations of outcrops of this material in the vicinity and our experience indicate that these deposits are dense and suitable for foundation support for the proposed residential structure. However, the foundation excavations should be observed by a representative of this firm prior to placing steel or concrete in order to confirm that the intended bearing materials have been reached. If the proposed building location is changed,this office should be consulted for additional evaluation and/or field investigation. Slope Stability The western portion of the property comprises an approximately 120-foot-high 1.3 HN to 1.5:1 HN (horizontal:vertical) wooded slope. The gradient and height of this slope warrants its inclusion in the Critical Areas Ordinance for the County. We traversed this slope on February 2, 2005 and found it to be of relatively uniform gradient and orientation, with no indications of large-scale instability. The toe of this slope has been modified by past grading (cutting). It has been cut back (truncated) to a gradient of approximately 1:1 HN for a height of approximately 6 to 8 feet. Minor surface sloughing was evident at the toe of this cut and small excavations reportedly made by children were present. The vegetation on the undisturbed slope includes a cover story consisting of mature second-growth evergreens, 50 feet or more in height and mature second growth deciduous trees ranging from saplings to greater than 2 feet in diameter. The evergreens are mainly Douglas fir and western hemlock. Western red cedar is generally absent from the subject property. The deciduous trees were generally represented by big leaf maple and red alder. The trunks of the evergreen trees are generally straight and vertical (not butt-bowed or distorted). We also observed numerous large-diameter old-growth conifer stumps. The deciduous trees generally did not appear to be displaced except for light-seeking orientations. The ground cover generally consists of a mixture of salal,huckleberry and sword fern. We did not encounter any geomorphic expressions of past slope instability such as hummocky ground, ground cracks, terraced topography or bowed or arched trees. We did not encounter evidence of surface File No.11951-001-00 Page 3 G EOE NG INE E R5� March 11,2005 flow or seepage of groundwater on the slope. We did not observe standing water in the project area at the time of our site visit. We made observations in adjacent areas to the north and south of the subject property along the same generally easterly facing slope. While the northward and southward extensions of the subject slope continue to be relatively uniform for several properties distant, we observed evidence of seepage locally through surface soils along contacts with denser underlying native materials, revealed primarily by vegetation trends. These conditions appeared to be generally absent from the subject property. Based on our site observations and experience with the subject geologic units and the site area, it is our opinion that the potential for gross slope instability is low. The westerly ascending slope to the west was found to be of relatively uniform plane and gradient, with no indications of gross instability. However, the base of the slope is partially truncated by an approximately 6 to 8-foot-high 1:1 H:V cut. While this cut does not render the slope grossly unstable, it does undermine the more porous upper soil layer (approximately 2 to 4 feet deep), which, when saturated, may be prone to surficial raveling and slumping. A building setback of 25 feet from the base of the slope is recommended. Alternatively, an engineered retaining wall (with adequate back drainage, foundation embedment and reinforcing) can be installed along the base of the westerly ascending slope. Laboratory testing and slope stability analyses were beyond the scope of this report. BUFFERS Ordinance 17.01.100, "Landslide Hazard Areas," of the Mason County Resource Ordinance, Section D-6 "Buffers" states that "A 50-foot (15.25 meter) buffer of vegetation is required around the Landslide Hazard Area." The subject building pad area has already been cleared, apparently many years ago as indicated by the presence of two large trees in the approximate center of the pad. Due to the excavated toe of the westerly ascending slope, the surficial soils immediately upgradient of the cut are undermined and may ravel with time. We, therefore, recommend that all structures be set back a minimum 25 feet from the toe of the westerly ascending slope. We also recommend that the remaining native slope vegetation be maintained to reduce the incidence of surficial erosion and sloughing except as noted below. CONCLUSIONS AND RECOMMENDATIONS Based on our site reconnaissance and experience in the area, it is our opinion that the site is generally suitable for the proposed development from an engineering geologic standpoint. The westerly ascending slope to the west of the subject building pad is generally of uniform orientation and gradient with no significant terraces, humps or other indications of deep-seated landslide movement. The cover story of trees revealed no indication of unstable slope conditions and appears to be of the type that prefers well- draining soils. We did not observe evidence of surface flow or emanation of water, shallow groundwater seepage or other groundwater flow. Provided the recommendations presented in this report are followed and representatives of GeoEngineers, Inc. are retained to review the plans and observe grading activities, foundation excavations and installation of designed drainage devices, it is our opinion that a Geotechnical Report is not necessary to further evaluate site conditions and the proposed development of the property. It is a relatively common occurrence for large or tall trees on steep slopes to blow over or topple with storm or wind events or due to normal aging, health (disease) or decay processes. This can present a special hazard to people and structures. We recommend that an arborist be consulted regarding any large trees which could topple in the direction of proposed structures. Deliberate removal of these trees will File No.11951-001-00 Page 4 GMENGINEER� March 11,2005 not, in our opinion, compromise slope stability, provided that ground disturbance and ground cover vegetation is avoided. Conventional erosion control features such as silt fences and loose straw ground cover, sand bags, and trenching may be appropriate for this site, depending upon the design and grading options chosen. Review of the need for such structures was beyond the scope of this report. LIMITATIONS We have prepared this report for the exclusive use by Maryann Spires, John Gray and their design consultants for the proposed single-family residence at the subject property. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of engineering geology in this area at the time this report was prepared. No warranty or other conditions,express or implied, should be understood. File No.11951-001-00 Page 5 GMENGINEERS� March 11,2005 �a P� o` o` ong Marsh S 3 �+ � N Fem aY ✓°nes 2(u 2 Rd a. z d m N SITE a 6 y v � a 3 e r,a O J � NE Myer pr QD H m N E ch r Z NE Seitz r -' m%�i Way Z a L ~ o sa a� w 6 Z N N m Z � C 2 7 N 2 a) LL U N V1 N c. m � o0 x m NEBa�a r� m ra v L) "- Lorrain C ° Z C hS` m y r Ma hew Puget Sound/Pacific Ocean LU E �°fie m F 0 I 0 o Data Sources: Interstates,state routes,and roads from TIGER 2000. o County boundaries,cities,and waterbodies from Department of Ecology. 01 = 16 °LO' 01 3 All locations are approximate. L K tsap ( o Lambert Conformal Conic 0 1,000 2,000 Mason county State Plane North Feet o North American Datum 1983 County L rn 0 Note:This drawing is for informational purposes. It is intended to assist 0 Pierce in showing features discussed in an attached document. CCU at)( 75 a It is unlawful to copy or reproduce all or any part thereof,whether for personal use or resale,without permission. Q VICINITY MAP GEOENGINEER FIGURE 0 M9 Eg Eh r � A � a' f .� Ab f �e, �Cll { 1 �Mg e r)i` ;�J I (� Ef E t o ! p 7 Eh'V l B / ;�. M9 z 1 ,tits' SITE Y / .f Ib (`r Ic. B }} \ s J•, r r h .kr C c tIl � 13 Eh l la C Eh Sa 71 to04 Er J v ! B ECIO �. /• f .Ee � �Ea Mh iEa ••Ba Tn U- Ad Cc � , Tn` L Mh Mobi a N �� i r 7 Ee .---,� l � �Ee. .t z ti W�. RG�������27ee'��'a s. � � �Eh 1• ( f o� Ib)• �F vfi�`�� Sr > Kf ' li t. `�• �j f 0 o Data Sources: Interstates,state routes,and roads from TIGER 2000. o County boundaries,cities,and waterbodies from Department of Ecology. „ Drainage rn NRCS soils data from United States Department of Agriculture. USGS quadrangle(4 meter resolution)from TerraServer (obtained February 2005). State Routes o All locations are approximate. Soils Boundary oLambert Conformal Conic Washington State Plane North 0 1,000 2,000 ® Site Boundary cNorth American Datum 1983 Feet Note:This drawing is for informational purposes. It is intended to assist Eg = Everett gravelly sandy loam, a in showing features discussed in an attached document. 0% to 5% Slopes. m It is unlawful to copy or reproduce all or any part thereof,whether for personal use or resale,without permission. a Q SOIL SURVEY MAP GMENGINEERS _.� FIGURE 2 0 GEOENGINEERS APPENDIX A REPORT LIMITATIONS AND GUIDELINES FOR USE i APPENDIX A REPORT LIMITATIONS AND GUIDELINES FOR USE' This appendix provides information to help you manage your risks with respect to the use of this report. GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES, PERSONS AND PROJECTS This report has been prepared for the exclusive use of Maryann Spires, John Gray and their authorized agents. This report is not intended for use by others, and the information contained herein is not applicable to other sites. GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction contractor or even another civil engineer or architect that are involved in the same project. Because each geotechnical or geologic study is unique, each geotechnical engineering or geologic report is unique, prepared solely for the specific client and project site. Our report is prepared for the exclusive use of our Client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. This is to provide our firm with reasonable protection against open-ended liability claims by third parties with whom there would otherwise be no contractual limits to their actions. Within the limitations of scope, schedule and budget, our services have been executed in accordance with our Agreement with the Client and generally accepted geotechnical practices in this area at the time this report was prepared. This report should not be applied for any purpose or project except the one originally contemplated. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT IS BASED ON A UNIQUE SET OF PROJECT-SPECIFIC FACTORS This report has been prepared for a proposed single-family residence located at 61 Steelhead Drive North, Belfair, Washington. GeoEngineers considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless GeoEngineers specifically indicates otherwise,do not rely on this report if it was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored,or • completed before important project changes were made. For example,changes that can affect the applicability of this report include those that affect: • the function of the proposed structure; • elevation,configuration,location, orientation or weight of the proposed structure; • composition of the design team; or • project ownership. Developed based on material provided by ASFE,Professional Firms Practicing in the Geosciences;www.asfe.org. File No.11951-001-00 Page A-1 March 11,2005 GWENGINEER� If important changes are made after the date of this report, GeoEngineers should be given the opportunity to review our interpretations and recommendations and provide written modifications or confirmation, as appropriate. SUBSURFACE CONDITIONS CAN CHANGE This geotechnical or geologic report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by manmade events such as construction on or adjacent to the site, or by natural events such as floods, earthquakes, slope instability or ground water fluctuations. Always contact GeoEngineers before applying a report to determine if it remains applicable. MOST GEOTECHNICAL AND GEOLOGIC FINDINGS ARE PROFESSIONAL OPINIONS Our interpretations of subsurface conditions are based on field observations from widely spaced sampling locations at the site. Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then applied our professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. GEOTECHNICAL ENGINEERING REPORT RECOMMENDATIONS ARE NOT FINAL Do not over-rely on the preliminary construction recommendations included in this report. These recommendations are not final,because they were developed principally from GeoEngineers' professional judgment and opinion. GeoEngineers' recommendations can be finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability for this report's recommendations if we do not perform construction observation. Sufficient monitoring, testing and consultation by GeoEngineers should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities are completed in accordance with our recommendations. Retaining GeoEngineers for construction observation for this project is the most effective method of managing the risks associated with unanticipated conditions. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT COULD BE SUBJECT TO MISINTERPRETATION Misinterpretation of this report by other design team members can result in costly problems. You could lower that risk by having GeoEngineers confer with appropriate members of the design team after submitting the report. Also retain GeoEngineers to review pertinent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering or geologic report. Reduce that risk by having GeoEngineers participate in pre-bid and preconstruction conferences, and by providing construction observation. File No.11951-001-00 Page A-2 March 11,2005 CiEOENGINEER� GIVE CONTRACTORS A COMPLETE REPORT AND GUIDANCE Some owners and design professionals believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering or geologic report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with GeoEngineers and/or to conduct additional study to obtain the specific types of information they need or prefer. A pre- bid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. Only then might an owner be in a position to give contractors the best information available, while requiring them to at least share the financial responsibilities stemming from unanticipated conditions. Further, a contingency for unanticipated conditions should be included in your project budget and schedule. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to on-site personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments, claims and disputes. GeoEngineers includes these explanatory "limitations"provisions in our reports to help reduce such risks. Please confer with GeoEngineers if you are unclear how these "Report Limitations and Guidelines for Use"apply to your project or site. GEOTECHNICAL, GEOLOGIC AND ENVIRONMENTAL REPORTS SHOULD NOT BE INTERCHANGED The equipment, techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly,environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. BIOLOGICAL POLLUTANTS GeoEngineers' Scope of Work specifically excludes the investigation, detection, prevention, or assessment of the presence of Biological Pollutants in or around any structure. Accordingly, this report includes no interpretations, recommendations, findings, or conclusions for the purpose of detecting, preventing, assessing, or abating Biological Pollutants. The term`Biological Pollutants" includes, but is not limited to,molds,fungi, spores,bacteria,and viruses,and/or any of their byproducts. File No.11951-001-00 Page A-3 March 11,2005 GMENGINEERS_