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HomeMy WebLinkAboutGEO2018-00029 for BLD2018-00370 - GEO Geological Review - 5/30/2018 �.�v{�� �� ,P 2�✓�1 l��zz�8 GEOZoIS CCD2q Mason County Review Checklist For a Geological Assessment Instructions: This checklist is intended to assist Staff in the review of a Geological Assessment. The Assessment is reviewed for completeness with respect to the Resource Ordinance. If an item is found to be not applicable, the report should explain the basis for the conclusion. The Assessment is also reviewed for clarity and consistency. If the drawings, discussion, or recommendations are not understandable, they should be clarified. If they do not appear internally consistent or consistent with the application or observations on site, this needs to be corrected or explained. If resolution is not achieved with the author, staff should refer the case to the Planning Manager or Director. Applicant's Name: Permit#: � �� a��� Parcel#'s: 2J3 Date(s) of the Document(s) reviewed: 1. A discussion of geologic conditions in the general vicinity of the proposed development,with geologic unit designation based on referenced maps. OK? 7 Comment: 2. (a) A discussion of the ground water conditions at the site, OK? `� Comment: (b) A discussion of the estimated depth to water, OK? � Comment: (c) A discussion of the quantity of surface seepage, OK?�_Comment: (d) A discussion of the upslope geomorphology, OK?_y"" Comment: (e) A discussion of location of upland waterbodies and wetlands. OK? ,/ Comment:_ I U ? 3. The approximate depth to hard or dense competent soil, e.g. glacial till or outwash sand. OK? Comment: 2 ' l t l oo-�L o"p cvn L 4. A discussion of any geomorphic expression o p s ope ins a me or nUMMgCKY ground cracks, terraced topography indicative of landslide block movement, bowed or arched trees indicating downslope movement, etc.). OK? ✓ Comment: 5. A discussion of the history of landslide activity in the vicinity, as available in the referenced maps and records. 1� OK? ✓ Comment: An opinion on whether the proposed development is within the landslide hazard area or its associated buffer or (4 setback and the potential for landslide activity at the site in light of the proposed development. OK? Comment: 1% i'c �w A recommendation by the preparer he �eotehnical Repor s�oulc!`be required to f rther evaluate site VX conditions and the proposed development of the subject property. OK? -_Comment: 8. If the presence of a hazard is determined within 300 feet of the proposed development, then the following are delineated on a geologic map/site map: Pagel of 2 Form Effective June 2008 (a) the area of the proposed development, 0 OK? Comment: I lk'(b) the boundaries of the landslide hazard area (top, both sides, and toe), OK? ✓ Comment: N(c) the associated buffers (top, both sides, and toe) OK? ✓ Comment: *-(d) building or other setbacks (top, both sides, and toe). o f OK? Comment: t2a, 6 vA 1 Q c S se oP �- �10l #9. A site map drawn to scale showing he property boundaries, scale, north arrow, and the location and nature of existing and proposed development on the site. OK? Comment: a e. r �� �ty�}- ��lLo� 1 fl e�-+i cw— n�f7, - ✓ eL�i57,'N� c�ti�oL�v,-aPoeic/� Are the Documents signed and stamped? �_By whom? a wj�.y IbLe9-% License#: ` License type: i"'1 FIRST REVIEW ❑ Approved Er Need more info. If not approved, what is the next action/recommendation for further action? i tj Dal;? L12U I 1­1c7U F-D9441IArl D&D 7-1 O DLAO I vY\Q ct L-e sv / / 0.4 1�-lD• of �tt%t-T7 t-d ►�•� �ti��l,ocl�� ��oYfi. Reviewed by on Time spent in review: A!:—' SECOND REVIEW/UPDATE ❑ Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by on . Time spent in second review:-4-5►'yl n THIRD REVIEW/UPDATE ❑ Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by on . Time spent in third review: Disclaimer.- Mason County does not certify the quality of the work done in this Geological Assessment Page 2 of 2 Form Effective June 2008 1 a��l -a -1'b ►�1 EL 218 -0002,9 INSIGHT GEOLOGIC, INC. , 2 g �"�J 615 W.Abler Street May 21, 2018 CRMA Investments, LLC 4621 Lacey Boulevard Lacey, Washington 98503 Attention: Matt Abbey Geologic Assessment Report 20 NE Quail Trail Belfair, Washington Project No. 791-003-01 INTRODUCTION Insight Geologic, Inc. is pleased to provide our geotechnical report of your property located at 20 NE Quail Trail near Belfair, Washington. The project site consists of a single parcel of land, irregularly shaped, consisting of about 0.63 acres. The location of the site is shown relative to surrounding physical features in the Vicinity Map, Figure 1. We understand that you have removed a pre-existing manufactured home and are intending to replace that structure with a similar manufactured home in approximately the same location. According to Mason County staff, the property contains areas that may meet the definition of a steep slope(25 percent slopes greater than 10 feet in height) under Mason County's Critical Areas Ordinance for Geologically Hazardous Areas. SCOPE OF SERVICES The purpose of our services was to evaluate geologic conditions as they relate to slope stability on the subject property. We performed our evaluation in general accordance with the procedures outlined in Mason County's Critical Areas Ordinance. The specific tasks performed for this project are outlined below. 1. Evaluate critical slopes on the property relative to the definition of steep slopes and the potential for landslide hazard in conformance with Mason County Resource Ordinance, Title 8, Chapter 8.52. 2. Evaluate local geology in the area of the parcel by reviewing readily available geologic reports and local water well logs, as well as conducting a site reconnaissance to view exposed geologic units in the critical slope areas. 3. Prepare a report for review by Mason County summarizing our activities and presenting our opinion on slope stability at the subject site. LANDSLIDE HAZARD AREAS The regulations established in the Mason County Resource Ordinance,Title 8, Chapter 8.52 Landslide Hazard Areas are intended to"identify areas that present potential dangers to public health and safety, 1015 EAST 4TH AVENUE, OLYMPIA, WASHINGTON 98506 PHONE: 360.754.2128 FAx: 360.754.9299 Y t Quail Trail Property Geologic Assessment Report May 21, 2018 to prevent the acceleration of natural geological hazards, to address off-site impacts, and to minimize the risk to the property owner or adjacent property owners from development activities." Pertinent landslide and erosion hazard issues related to the site are addressed in the remainder of this report. The purpose of this study and report is to evaluate the slope stability of the site in accordance with Mason County Resource Ordinance, Title 8, and Chapter 8.52. "Landslide hazard areas"means those areas with any indications of earth movement such as debris slides, earth flows, slumps and rock falls; areas with artificial over-steepened or unengineered slopes; areas containing soft or liquefiable soils; areas over-steepened or otherwise unstable as a result of stream incision, stream bank erosion and undercutting by wave action; slopes greater than 15 percent(8.5 degrees) or having the following: a.) hillsides intersecting geologic contacts with relatively permeable sediment overlying relatively impermeable sediment or bedrock and having springs or groundwater seepage; b.) any area with a slope of 40 percent (21.8 degrees), or steeper and a vertical relief of ten or more feet, except areas composed of consolidated rock. Surface Conditions The project site is bounded by a residential property to the east, Highway 300 to the south, NE Quail Trail to the west and NE Quail Trail and a natural slope to the north. Topographically, the building site is generally level, but the property slopes down on the south and west sides at inclinations ranging between 32 and 36 degrees (62 to 72 percent). The base of the slope on the west side has a timber retaining wall approximately 4 feet high along NE Quail Trail. The maximum slope height on the property occurs between the building pad and Highway 300 and is approximately 25 feet high. The natural slope to the north of NE Quail Trail is inclined at 40 degrees (84 percent). The slopes to the north, west and south are well vegetated with trees and brush. Vegetation on the property slopes consists of alder and maple between 6 and 12 inches in diameter. We observed minor bowing of a few trees located near the top of the slope at the site, indicating soil creep in these areas. We did not observe the presence of geologic contacts, springs, seeps or hydric vegetation on the slopes. We did not observe indications of hummocky or back-tilted topography indicating past soil failures. Geology Based on our review of available published geologic maps, Vashon age glacial till deposits underlie the project site and surrounding area. Glacial till consists of a dense, unsorted mixture of silt, sand and gravel, which has been compacted by the weight of overriding glacial ice. Till tends to have a high compressive strength and a high angle of internal friction. No upland wetlands or waterbodies appear to be present on the property. We were unable to identify any mapped landslides within 1,000 feet of the site using the Washington State Department of Natural Resources landslide database. The surficial soils observed on the property are generally consistent with Indianola loamy sand, which is mapped for the area. These soils are formed from glacial outwash and tend to have moderate infiltration rates and slow runoff. FILE No. 791-003-01 2 Quail Trail Property Geologic Assessment Report May 21, 2018 Groundwater A review of the Washington State Department of Ecology Well Log Records for the surrounding area indicates groundwater levels at a depth of approximately 120 feet below ground surface. No well logs were found for the subject parcel, however a well log was located for a property to the north of the site. The referenced well log is shown in Attachment A. FINDINGS Insight Geologic visited the site on May 1, 2018 to evaluate the site slopes and surface conditions. The proposed building site is located north of North Shore Road (Highway 300)and south of NE Quail Trail. The soils exposed at the building site generally consisted of silty fine to medium sands with minor gravels(Indianola). These soils are consistent with Vashon-age glacial till and advance outwash deposits that have been glacially compacted and are generally equivalent with soils identified in the well log for the nearby property. No evidence of bedding planes, seeps, hydric vegetation or indications of past slope instability were noted during our site reconnaissance. Two small trees near the top of the southern slope showed indications of soil creep. Based on multiple measurements made using a hand-held clinometer, the slopes at the site ranged from approximately 32 degrees to 36 degrees (62 to 72 percent) adjacent to the proposed building site, to about 40 degrees (89 percent)for the natural slope to the north of NE Quail Trail. CONCLUSIONS AND OPINION Based on the site visit observations and published information of soils in the area of subject parcel, it is our opinion that the slopes adjacent to the proposed building area meet the definition of a"Landslide Hazard Area" due to inclination. The slopes all exceed the 40 percent inclination criteria as outlined in the Mason County Resource Ordinance. However, the slopes do not exhibit geologic contacts, springs or seeps as outlined in the ordinance. No evidence of past landslides was observed. A completed Geological Assessment Checklist is included in Attachment B. The site geology consists of Vashon-age glacially consolidated till and outwash units. It is our opinion that the glacial till deposits on the site have inherent internal strength and a high angle of internal friction, which are not prone to deep-seated failures. The outwash materials are permeable and not prone to failure. Minor sloughing or raveling may occur on steeper slopes due to weathering of the soil, but these sloughs do not represent a risk to the proposed residential structure. Based on our observations and evaluation of the site, we would normally recommend a minimum setback of 15 feet from the top of the slope for the proposed structure. This setback is based on the underlying geologic material, constraints of the property and past site use. No additional subsurface geotechnical explorations or slope stability analyses are required for this project. In general, care should be taken during and after construction to maintain good, positive drainage from all impervious surfaces. Drainage should be collected into catch basins and contained in non- perforated piping for discharge at the base of the slope. Drainage from roof downspouts should also be collected into non-perforated piping and directed away from the slope, or to the base of the slope for discharge. All stormwater infiltration and septic drainfields should be sited outside of the setback area. FILE No. 791-003-01 3 Quail Trail Property Geologic Assessment Report May 21, 2018 Native vegetation should be maintained whenever possible and exposed soil protected from rainfall. Detailed clearing and grading plans and temporary erosion control plans should be prepared and submitted by an appropriate contractor. The wet weather season in this area generally begins in October and continues through May. However, periods of wet weather may occur during any month of the year. If wet weather earthwork is unavoidable, we recommend that: • The ground surface is sloped so that surface water is collected and directed away from the work area to an approved collection/dispersion point. • Earthwork activities not take place during periods of heavy precipitation. • Slopes with exposed soil be covered with plastic sheeting or otherwise protected from erosion. • Measures are taken to prevent on-site soil and soil stockpiles from becoming wet or unstable. Sealing the surficial soil by rolling with a smooth-drum roller prior to periods of precipitation should reduce the extent that the soil becomes wet or unstable. • Construction traffic is restricted to specific areas of the site, preferably areas that are surfaced with materials not susceptible to wet weather disturbance. • A minimum 1-foot thick layer of 4-to 6-inch quarry spalls is used in high traffic areas of the site to protect the subgrade soil from disturbance. LIMITATIONS We have prepared this geologic assessment report for use by you and your authorized agents for the property located at 20 NE Quail Trail in unincorporated Mason County, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geological engineering in this area at the time this report was prepared. No warranty or other conditions express or implied, should be understood. Please refer to Attachment C, Report Limitations and Guidelines for Use, for additional information pertaining to use of this report. FILE No. 791-003-01 4 Quail Trail Property Geologic Assessment Report May 21, 2018 We appreciate the opportunity to be of service to you on this project. Please contact us if you have questions or require additional information. Respectfully Submitted, INSIGHT GEOLOGIC, INC. wept Wuah�' William E. Halbert, L.E.G., L.HG. OOle- ` 8 8 Principal Aij$ed Ggo�o William E. Halbert Attachments FILE No. 791-003-01 5 FIGURES Mason County Department of Community Development Submittal Checklist For a Geological Assessment Instructions: This checklist must be submitted with a Geological Assessment and completed,signed, and stamped by the licensed professional(s)who prepared the Geological Assessment for review by Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not applicable,the report should explain the basis for the conclusion. Applicant/Owner U44 W- X.4J(IM7 Parcel# Site Address ZO ©rJ-a t ( 'T�ZA (1) A discussion of geologic conditions in the general vicinity of the proposed development,with geologic unit designation based on referenced maps. Located on page(s) 7 (2) (a)A discussion of the ground water conditions at the site, Located on page(s) 3 (b) A discussion of the estimated depth to water Located on page(s) 7� (c) A discussion of the quantity of surface seepage Located on page(s) (d) A discussion of the upslope eomorphology Located on page(s) (e) A discussion of location of upl nd waterbodies and wetlands. Located on page(s) / er:41 j (3) The approximate depth to hard dense competent soil, e.g.glacial till or outwash sand. Located on page(s) t (4) A discussion of any geomorphic expression of past slope instability(presence of hummocky ground or ground cracks,terraced topography indicative of landslide block movement, bowed or arched trams indicating downslope movement,etc.). Located on page(s) l.� (5) A discussion of the history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) (6) An opinion on whether the proposed development is within the landslide hazard area or its associated buffer or setback and the potential for landslide activity at the site in light of ( the proposed development. r Located on page(s) (7) A recommendation by the preparer whether a Geotechnical Report should be required to further evaluate site conditions and the proposed development of the subject property. Page 1 of 2 Form Effective June 2008 h N �y 1: Located on page(s) (8) If the presence of a hazard is determined within 300 feet of the proposed development, then the following are delineated on a geologic map/site map: (a) the area of the proposed development, Located on Map(s) P., l (b) the boundaries of the landslide area (top, both sides, and toe), Located on Map(s) (c) the associated buffers(top,both sides,and toe) Located on Map(s) (d) building or other setbacks(top, both sides, and toe). Located on Map(s) (9) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of existing and propos d development on the site. Located on Map(s) �( f.. 14-, �! 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. 1 also certify that the Geological Assessment, dated / , and entitled l I �✓l meets all the requirements of the Mason County Resource Ordinance, Landslide Hazard Section, is complete and true,that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geotechnical design recommendations, and that all hazards are mitigated in such a manner as to prevent harm to property and public health and safety. (Signature and Stamp) 1 tiO�t Waah�' l� w used Ge0 William E. Halbert Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment. I Page 2 of 2 Form Effective June 2008 i l� 1�fI� 1'�, \ t•• t ��Ir� �( � �, � •�1 r'jODI ( r � t � V 5 p� I\I�iR RIVER �o w1 E ARt% Bm- J r! O� stMob'eLHothe P rk li�� < ��'i1• MUD � yx Pe ✓ � 1 � ParkELFAI AT �g • Bt:LfA _ P Ca ipyround C { P1urn Pt I•i I , BELFAIR, WASHINGTON 7.5 MINUTE QUADRANGLE Ii Year1994 1 SCALE:1:24000 QUAIL TRAIL PROPERTY LEWIS COUNTY,WASHINGTON Figure 1 INSIGHT GEOLOGIC, INC. ���� Vicinity Map .p Air sil f. 54 .� '1 f J y�C LEGEND: —---- APPROXIMATE PROJECT BOUNDARY 1 ( N.T.S QUAIL TRAIL PROPERTY MASON COUNTY.WASHINGTON Figure 2 INSIGHT GEOLOGIC. INC. Site Plan Q LEGEND: APPROXIMATE PROJECT BOUNDARY N.T.S QUAIL TRAIL PROPERTY MASON COUNTY,WASHINGTON '-N Figure 3 INSIGHT GEOLOGIC, INC. ���+r Geologic Map ATTACHMENT A WELL LOG ennf�ardNa, W 061311 flpmrbrirwla cology Firg opywllh WATER WELL REPORT UNIQUE WELLI.D.#__ Dapartmattt of Ecology Baeondcopy—owrtar'sCopy STATE OF WASHINGTON Third Copy—OWW's Copy Water Right Part No, i (1) OWNER: Name ohn Bver v Ridge Renner _Water Add�a tdF 3gf} Larson Lk Rd Belfair WA 98528 0) (2) LOCATION OF WELL: crony Mason SW It,; ec NW i,s s 31 T. 23 N,R 1W wM. c (2s) sn3EET ADDRESS OF WELL(or a,"tieidnia.) NE 390 Larson Lk Rd Belfair WA 98528 Xi Domesbc 10 WELL LOG or ABANDONMENT PROCEDURE DESCRIPTION (3) PROPOSED USE: Induttdtl ❑ Municipal ❑ ( ) ❑ Inigation Test WON ❑ ()d"tf L1 Formation:Dewtbs by color.character,size of male6ai and atructurs,and show thickness of owiters y ❑ Dewatw and the kind tad nature of the matwlaf In each stratum penetrated,with N bast one entry tot secfh f3 (4) TYPE OF WORK: Owners number of welt change of nro rnat on. _ -- (It more than one) --- — MATEMAL FROM TO Abandoned U New wall x Method:Dug Cl Bored❑ O Deepened ❑ Cabled Drivenrl r_ Reconditbnad❑ Rotary❑ detnd❑ (5) DIMENSIONS: Diameter of well 6 Inch". _ Drilled 155 lost. Depth of completed well— _ 155 R. Brown con lomorate 18 46 (6) CONSTRUCTION DETAILS: Casing Installed: �' Dam.hom� R to 150 R. C Welded , Dtern.from R.to— R. Unat,>ugedr , aam from R t' ftBrown co lomorate 58 100 Thranded u ,,, varrw.tlort.: Yee p Na ff7 Blue clay with gravel & water 100 154 0 Type of pertoroor used V SIZE of pedorabone in,by In, Sand & gravel with at-or 154 156 R _ perforations from _fL W A. perforations from _R.to h. perforations from _R.to R scroeria: Yes 5d No❑ 0) Manuladurer'aName Houston _ 6 Type stainless wire wrap mom No. -- �► Diem. __5_slot size 0_ .—Tram 15d _R.to 155 Darn _Slot size hem R,14 ^R. Gravel pocked: Yos❑ No 0 Site of gravel L cc Gravel Gravel placed trom ft.to_ h. Strfausaaf: Yes ® ❑N.o,�❑ Tawhatd"Ih? OMaterial used in eed SAtan P _ Z Did any strata contain unusable water? Yes El No KI N Type of water? Depth of strata_ Al Mathal of s161ng strata oft _.__.__ 'a (7) PUMP: Menu(actursr'sNoma Grundfos >s Type: N.P. O (e) WATER LEVELS' -nd-awtkoa Movation Work started_6/15/95 .w. 00"Vie d 6123,[95 n+sen a"level fl. Q Static Wool_ 1Q7 t 3 _ h.Dhow Wp of�a Dati WELL CONSTRUCTOR CERTIFICATION: W Anesttn squ pleasors fbo.per are Inch Data W Artesian*star m controlled ty O (Cap.v vr,e I constructed and/or adept reaponsrbiiity for construction of this welt, and its comptianoe with all Washington wall construction standards.Materials used and the Information reported above are true to my best knowledge and belief. d.+ (1i) WELL TEST'S: Drawdovrn is amount water bwl Is lowered below static level " C Wee a pump test made?Yes® No❑ If yse,by whom? Da is D i 1 !_Da 1 t�PDEor+rwt+ '— Yield: � id: _ .4__.gal,Jmin.with 5— _2. R.drewdawnagar�,.,_fre. NAME t . 14 2.5 N Addrm Be 9 528 (Sig " ) No. ) Recovery dale(time taken as tote when pump turned oft/(water bust moasurW from wWl � Ucanaa to 1992 i g top to water WvW) Water level t Time Water Level Time Wow LevelCantractor'a V _109.75 — Registration 107.29 — _ No, DAVTSDT'1_10DA Date June _ tg (USE ADDITIONAL SHEETS IF NECESSARY) Date of tau _ awler test gtl.tmin.with ft drandown after his. Ecology Is an Equal Opportunity and Affirmative Action employer.For spe- Airtesl gal.Imin,wHh ttom set at tL for_, hrs. p,p.m, Dale cfai accommodation needs,contact the Water Resources Program at(206) Artesian now Temveralurs of water__Was a chemical sntlykts made? Yea❑ No® 407 6800.The TDD number Its(208}A07.8008, ATTACHMENT B MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT SUBMITTAL CHECKLIST FOR A GEOTECHNICAL REPORT ATTACHMENT C REPORT LIMITATIONS AND GUIDELINES FOR USE ATTACHMENT C REPORT LIMITATIONS AND GUIDELINES FOR USE' This attachment 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 CRMA Investments, LLC (Client) and their authorized agents. This report may be made available to regulatory agencies for review. This report is not intended for use by others, and the information contained herein is not applicable to other sites. Insight Geologic Inc. 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 Insight Geologic, Inc. considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless Insight Geologic 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. If important changes are made after the date of this report, Insight Geologic should be given the opportunity to review our interpretations and recommendations and provide written modifications or confirmation, as appropriate. 1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org. INSIGHT GEOLOGIC, I N C. LIMITATIONS 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 Insight Geologic 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. Insight Geologic 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 Insight Geologic's professional judgment and opinion. Insight Geologic's recommendations can be finalized only by observing actual subsurface conditions revealed during construction. Insight Geologic cannot assume responsibility or liability for this report's recommendations if we do not perform construction observation. Sufficient monitoring, testing and consultation by Insight Geologic 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 Insight Geologic 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 Insight Geologic confer with appropriate members of the design team after submitting the report. Also retain Insight Geologic 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 Insight Geologic participate in pre-bid and pre-construction conferences, and by providing construction observation. DO NOT REDRAW THE EXPLORATION LOGS Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical engineering or geologic report should never be redrawn for inclusion in architectural or INSIGHT GEOLOGIC, INC. LIMITATIONS other design drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs from the report can elevate risk. 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 fetter 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 Insight Geologic 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. Insight Geologic includes these explanatory "limitations" provisions in our reports to help reduce such risks. Please confer with Insight Geologic 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. INSIGHT GEOLOGIC, INC. LIMITATIONS