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Report (26) I t • r URS 6wcoi-(-605--i2eRRE.,5 /1n7 U 8,2 11 July 10, 2003 Tigard-Tualatin School District 23J 6960 SW Sandburg Street Tigard, Oregon 97223 Attn: Mr. Stephen Poage Director of Capital Projects Re: Geotechnical Investigation Alberta Rider Elementary School Tigard-Tualatin School District 23J Tigard, Oregon URS Job No: 25695391.10001 Dear Mr. Poage: • We are pleased to submit herewith our report entitled "Geotechnical Investigation, Alberta Rider Elementary School, Tigard-Tualatin School District 23J, Tigard, Oregon." This report formally documents our conclusions and recommendations regarding the proposed project. It has been our pleasure to assist you with this project. Should you have any questions regarding the contents of this report, please call us at your convenience. . Yours very truly, X00 PROFFS URS �'� GINE sips J 44, xe OREGON _ ._ f.,,,,„. _ 6._ .9 wo9,,,s!,,,,, ka 'IN J. tow" / ail - ,d/L B an J. Duevel,P.E. Brian M. Wi man, Ph . D' I EXPIRES: `2j'3 i /03 Manager, Geotechnical Engineering Project Engineer g g g URS Corporation 111 SW Columbia, Suite 900 Portland. OR 97201-5814 Tel: 503.222.7200 Fax: 503.222.4292 1 TABLE OF CONTENTS Section 1 Introduction 1-1 1.1 General 1-1 1.2 Proposed Construction 1-1 1.3 Scope of Work 1-1 Section 2 Field and Laboratory Investigations 2-1 2.1 Field Exploration 2-1 2.1.1 Test Pits 2-1 2.1.2 Subsurface Borings 2-1 2.1.3 Dynamic Cone Penetrometer 2-2 2.1.4 Field Resistivity 2-2 2.2 Laboratory Testing 2-2 Section 3 Site Description 3-1 3.1 Surface Conditions 3-1 3.2 Regional Geology 3-1 3.3 Subsuface Conditions 3-1 3.4 Slope Stability Accessment 3-2 3.5 Site Hydrogeology 3-2 Section 4 Design Recommendations 4-1 4.1 General 4-1 4.2 Shallow Foundations 4-1 4.2.1 Earth Pressures and Friction Factor 4-1 4.2.2 Slabs on Grade 4-2 4.3 Retaining Walls 4-2 4.3.1 Retaining Wall Design Parameters 4-2 4.3.2 Equivalent Fluid Densities 4-3 4.3.3 Additional Lateral Pressures 4-3 4.3.4 Retaining Wall Backfill 4-3 4.4 Site Preparation 4-4 4.4.1 General 4-4 4.4.2 Dry Weather Earthwork 4-4 4.4.3 Wet Weather Earthwork 4-4 4.4.4 Rock Rippability 4-4 • 4.4.5 Structural Fill 4-5 4.5 Slopes 4-5 4.6 Temporary Shroing 4-6 4.7 Seismic Design 4-6 4.8 Corrosion 4-6 4.9 Pavement Recommendations 4-7 URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 TABLE OF CONTENTS 4.10 Athletic Field Recommendations 4-8 Section 5 Sensitive Site Status 5-1 Section 6 Construction Monitoring 6-1 Section 7 Closure 7-1 Section 8 References 8-1 List of Tables Table 1 Measured Resistivity 4-6 Table 2 Laboratory Corrosion Tests ....4-6 Table 3 Assumed Traffic Loading ... 4-7 Table 4 Recommended Pavement Section ... 4-7 List of Figures Figure 1 Vicinity Map Figure 2 Site Map Figure 3 Standard Slab and Wall Drainage Detail List of Appendices Appendix A Subsurface Exploration Logs Appendix B Dynamic Cone Penetrometer Test Logs Appendix C Laboratory Testing Appendix D Wetlands Review URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\1 0-JUL-03 11 SECTIONONE Introduction 1.1 GENERAL This report presents the results of our geotechnical investigation performed for the proposed Alberta Rider Elementary School in Tigard, Oregon. This work was completed in accordance with our proposal to Tigard-Tualatin School District 23J dated May 16, 2003. The project site is located approximately as shown on the Vicinity Map, Figure 1. The Site Map presented on Figure 2 shows a preliminary plan layout of the site. The purpose of this investigation was to explore the surface and subsurface conditions at the site, analyze the conditions encountered, and prepare design and construction recommendations for support of the proposed school. These recommendations along with supporting data are documented in this report. 1.2 PROPOSED CONSTRUCTION This project involves the construction of a new school with an approximately 40,000 square feet footprint, a new entrance drive, parking lots, and athletic fields. At the time of this report, two separate manifestations of the planned development were available. This report is applicable to either development scenario. For the purposes of this report, we have assumed that column loads will not exceed approximately 80 kips and continuous wall loads will not exceed 3 kips per lineal foot. Specific loads and settlement criteria were not available at the time of this report. 1.3 SCOPE OF WORK The scope of this investigation included completion of the following: 1. Review of previous reports for geotechnical and geological information relevant to the site. This has been augmented with information obtained from site visits. 2. Examine historical aerial photographs to evaluate historical site development and slope instabilities. 3. Conduct a subsurface investigation consisting of drilling and sampling at 3 boring locations and 15 test pit locations to characterize the subsurface soils and bedrock. 4. Perform a laboratory testing program to characterize the physical and engineering properties of the subsurface soils,including moisture content, plasticity, and gradation. 5. Conduct a geologic site reconnaissance to identify and characterize any unstable conditions that could adversely impact the site and proposed development. 6. Complete a wetlands review for the site consisting of a site reconnaissance to evaluate the site for potential wetlands. 7. Recommendations for foundation support of the proposed school. These include foundation bearing capacities, footing sizes and depths, estimated settlements, earth pressures and the allowable sliding friction coefficient. 8. Recommendations for slabs-on-grade including subgrade preparation, base course gradation, compaction and subgrade modulus. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\1 0-JUL-03 1-1 SECTIONONE Introduction 9. Recommendations for retaining wall and below grade retaining wall design, including earth pressures for restrained and unrestrained retaining walls. Additionally, drainage and backfill recommendations are included. 10. General recommendations regarding construction and earthwork. 11. Determination of the corrosion potential at the proposed site with field and laboratory tests. These tests included field resistivity,pH, chloride and sulfate contents. 12. Perform dynamic cone penetration tests at the site to assess the in situ subgrade characteristics for pavement design. 13. Recommendations for pavement sections based on the anticipated traffic, pavement life, and soil conditions encountered. Both "light" and"heavy" duty sections are developed. 14.Recommendations for the design of new play fields including estimated percolation rates, settlements, drainage and construction considerations. 15. Preparation of 5 copies of this report describing our investigations and recommendations regarding geotechnical suitability of the site. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 1-2 SECTIONTWO Field and Laboratory Investigation 2.1 FIELD EXPLORATION The field exploration program was conducted on June 4, 5, 13, and 14, and July 1, 2003. The program consisted of a reconnaissance of the site for visual indications of slope instability and a subsurface exploration program. The subsurface investigation included the completion of 15 test pits, 3 soil borings, 11 dynamic cone penetrometer tests,and 4 field resistivity tests. 2.1.1 Test Pits The 15 tests pits were completed across the site, with a focus on the approximate location of the proposed school building, as shown on the Site Map, Figure 2. The test pits were excavated by Brownsfield Environmental and Construction, LLC., of Sandy, Oregon using a Case 9030B excavator. Test pits were completed to depths of between 12 and 19.5 feet below ground surface (bgs). The test pits were terminated in bedrock. Representative soil samples were collected from the test pits prior to being backfilled with the excavated soils. The test pit logs are presented in Appendix A. 2.1.2 Subsurface Borings Three soil borings were completed in the vicinity of the proposed school footprint, as shown on the Site Map, Figure 2. Drilling was performed by Geotech Exploratons, Inc., of Tualatin, Oregon using a truck-mounted CME-75 drill rig. Soil borings were terminated at depths ranging from 29 to 31 feet bgs and were all terminated in bedrock. Borings were advanced using hollow stem auger methods to competent bedrock and NX wireline coring methods to the completion of the boring. Upon completion of the borings, boreholes were backfilled with bentonite chips in compliance with the state of Oregon Water Resources Department requirements. The soil boring logs are presented in Appendix A. Soil samples were obtained during drilling by driving a 2.5 inch inside diameter / 3.25 inch outside diameter ring sampler (Dames & Moore Type-U) with a 300 pound hammer falling 30 inches. A 140 pound hammer was used to drive the sampler for B-03-2003. Recorded blows required to advance each 6 inches of penetration are shown on the boring logs. Sampling resistances for the Type-U Sampler were converted to equivalent Standard Penetration Resistances (N) using relationships from Winterkorn and Fang (1977) for engineering calculations. The N value is used to determine the in situ relative density of granular soils and the consistency of cohesive soils based on established correlations. Field reported blow counts are recorded on the boring logs. Retrieved ring samples were wrapped in watertight bags, placed in plastic containers, sealed, and temporarily stored in padded boxes for transportation to our laboratory. The soil boring logs are presented in Appendix A. The stratigraphic contacts indicated within each log represent the approximate boundaries between soil types; actual transitions may be more gradual and indistinct. The soil and groundwater conditions depicted are only for the specific dates and locations reported, and therefore, are not necessarily representative of other times and locations. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 2-1 SECTIONTWO Field and Laboratory Investigation 2.1.3 Dynamic Cone Penetrometer Twelve Dynamic Cone Penetration (DCP) tests were performed in areas of the site that may be paved. The DCP is a widely used device to determine the in situ strength properties of base materials and subgrade soils. The four main components of the DCP include the cone, rod, anvil and hammer. The cone is attached to one end of the DCP rod while the anvil and hammer are attached to the other end. Energy is applied to the cone tip through the rod by dropping the 17.64-pound hammer a distance of exactly 22.6 inches against the anvil. The diameter of the cone is 0.1575 inches larger than the rod to ensure that only tip resistance is measured. The number of blows required to advance the cone into the subsurface materials is recorded. The DCP index is the ratio of the depth of penetration to the number of blows of the hammer. This can then be correlated to a variety of material properties, including California Bearing Ratio (CBR) and Resilient Modulus. Logs of the DCP test results are included in Appendix B. 2.1.4 Field Resistivity The field resistivity of the soils at the site was measured with a Stratascout Model 40C resitivity meter. Resistance was measured using the 4-point (Wenner) configuration at equal spacings of 5, 10, and 20 feet between each electrode. Four resistivity tests were performed at the locations shown on the site map, Figure 2. 2.2 LABORATORY TESTING The soil samples collected as part of the surface and subsurface investigations were tested to refine the field classifications and to evaluate physical properties of the soils. All tests were conducted in general accordance with applicable ASTM standards. The laboratory testing program consisted of the following: • Visual Soil Classification in general accordance with ASTM Test Method D2487. • Grain size analysis — Mechanical Testing in general accordance with ASTM Test Method D422 and D1140. • Moisture Content in general accordance with ASTM Test Method D2937. • Liquid and Plastic Limits (Atterberg Limits) in general accordance with ASTM Test Method D4318. • pH in general accordance with EPA 150.1. • Chloride and sulfates in general accordance with EPA 300.0. The results of the physical laboratory tests conducted are summarized on the soil boring logs in Appendix A. Plots of the Atterberg Limit tests are contained in Appendix C. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 2-2 SECTIONTHREE Site Description 3.1 SURFACE CONDITIONS The site is located near the crest of Bull Mountain as shown on the Vicinity Map, Figure 1. The topography across most of the site is relatively gentle, with elevations ranging from a high of approximately 574 feet above Mean Sea Level (MSL) along the northwestern boundary to the site to 515 feet above MSL in the far southeast corner of the site. The maximum slopes present onsite approach 25% at the northwest edge of the site. Elsewhere, maximum slopes are approximately 15%, located in the northwest and southeast portions of the site. 3.2 REGIONAL GEOLOGY Regionally, the site is located in the northern Willamette Valley physiographic province, an elongate, roughly north-south trending alluvial valley that lies between the Coastal Range and Cascade Mountains to the west and east, respectively(On, et. al., 1992). It is also located within the Portland fold belt, a seismotectonic province defined by Unruh et al. (1994). The tectonic underpinnings of this latter province are not well understood and complicated by the fact that this area lies in a transition zone between the rotating forearc block and the continental interior (Wells et al, 1998). Specifically, the site is located in the Tualatin Basin, a northwest trending synclinal subbasin to the Willamette Valley basin (Unruh et al., 1994). The Tualatin Basin is fault bound along its eastern margin which is bound by the Portland Hills (Madin, 1990). Internal structure to the basin includes the faulting that has resulted in the formation of the Bull Mountain and Cooper Mountain anticlines. The site is located immediately south of the anticline axis as mapped by Madin. 3.3 SUBSURFACE CONDITIONS The results of the subsurface investigation show that the site is underlain by approximately 5 to 9 feet of medium stiff, brown, lean clay. This clay is weathered late Quaternary windblown silt. Underlying the weathered silts is 2 to 6 feet of stiff, reddish brown, lean clay. This clay is basalt bedrock residuum that grades to extremely to highly weathered basalt at depths ranging from 8 to 16 feet below ground surface. The basalt bedrock is Miocene-aged Columbia River Basalts. The highly weathered basalt is very weak (indicating it can be pealed with a pocketknife) and highly fractured. The degree of weathering gradually decreases with depth. The rock grades to moderately weathered, moderately strong (requiring a hammer blow to break a sample) basalt at depths between 21 and 26 feet bgs. The Rock Quality Designation (RQD) is commonly used as an index to describe a rock's degree of fracturing (Deere and Deere, 1989). The RQD is determined by summing the lengths of core pieces greater than 4 inches over a run and dividing this sum by the total length of the run. RQD values measured for the moderately weathered basalt ranged from 0 to 32 percent. The fractures per foot ranged from 5 to greater than 10. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 3-1 SECTIONTHREE Site Description 3.4 SLOPE STABILITY ASSESSMENT URS conducted a site reconnaissance and aerial photograph review to assess the site and surrounding properties for potential recent or ancient landslides. Aerial photographs from 1936, 1940, 1963, 1972, 1983, and 1996 were reviewed to assess the site and adjacent properties for historical slope instabilities. The 1936 and 1940 photographs indicate that the Rider residence is present along with buildings to the immediate south and east of the Rider property. The site and surrounding properties are open fields with some orchards. A steep sided drainage leads to the south-southeast from near the southeast corner of the site. The eastern portion of this site slopes towards this drainage. Slopes along this drainage appear generally stable though a potential small surficial failure is present approximately 1000 feet from the site in this drainage. Indications of global instability were not observed in the 1936 or 1940 aerial photographs. The drainage to the southeast of the site had become overgrown in the 1963 aerial photograph. There is a small slope failure immediately north of Beef Bend Road and south of the site by approximately 2000 feet. There is still one building present to the east and south of the Rider property. By 1972 the building to the south of the Rider property had been demolished. Indications of global stability issues were not observed in the 1963 or 1972 aerial photographs. The site is similar to as it appears today in the 1983 and 1996 aerial photographs. The building to the east of the Rider property is no longer present. The drainage to the southeast of the site is heavily overgrown and there are residential buildings on the east side of the drainage. James Schick, a URS Certified Engineering Geologist conducted a site reconnaissance on June 23, 2003. Evidence of slope instability was not observed on the site. A visual reconnaissance was also conducted in the drainage to the southeast. Indications of past slope failures including scarps, pistol-butt tree trunks, hummocky terrain or jackstrawed trees were not observed. Based on the aerial photograph review and site reconnaissance, there does not appear to be a significant slope stability issue associated with the site. 3.5 SITE HYDROGEOLOGY Groundwater was not encountered during the subsurface investigation. URS conducted a review of water well logs publicly available from the Oregon Water Resources Department. Static groundwater levels reported on well logs are in excess of 150 feet bgs in the vicinity of the site. Perched groundwater may be present within the fine-grained soils during the winter months. However, discharge from these perched systems is anticipated to be minimal. URS \\Por6tprojects\25695391 TTSD Albena Rider\TfSD Geotech.doc\10-JUL-03 3-2 SECTIONFOUR Design Recommendations 4.1 GENERAL Foundation loads for the new school building were provided to URS by Ellis Eslick Associates Architects. We understand that column loads are not anticipated to exceed 80 kips and continuous wall loads will not exceed 3 kips per lineal foot. Based on the soil conditions present at the site, URS recommends the use of conventional continuous or isolated shallow foundations be used to support the proposed structure. 4.2 SHALLOW FOUNDATIONS In our opinion, the school can be adequately supported with conventional continuous or isolated shallow footings. For footings that bear on shallow, undisturbed native soils, we recommend a net allowable bearing pressure of 2,000 pounds per square foot (psf). For footings founded at a depth of 10 feet or greater, we recommend a net allowable bearing pressure of 3,000 psf. Bearing pressures may be increased by one-third when considering transient loads such as wind and seismic forces. We recommend that a unit weight of 115 pounds per cubic foot (pcf)be used to calculate the overburden pressure due to excavation. Backfill soils will be slightly heavier than excavated soils but not enough to significantly influence the bearing pressure. Exterior footings should be founded at least 18 inches beneath the lowest exterior grade to provide frost protection. Continuous wall footings should have a minimum width of 18 inches and isolated column footings should have a minimum plan dimension of 24 inches. Given the anticipated column loads for the structure, square footings should have a minimum width of 6.5 feet. We recommend that excavations for foundations be accomplished with a straight-edged grading bucket to minimize disturbance of the bearing surfaces. Following excavation, the bearing surfaces should be thoroughly cleaned of loosened or disturbed soil, by hand if necessary. Any soft or unsuitable soils encountered at the base of foundation excavations should be removed and replaced with compacted structural fill meeting the requirements described below. For foundations designed and constructed as specified above, we estimate settlements on the. order of less than 0.5-inch. We anticipate that the majority of the settlement will occur during construction, essentially as the loads are applied. The remainder of the settlement will likely occur within three weeks following application of the loads. 4.2.1 Earth Pressures and Friction Factor . Passive earth pressures acting against the toe of the shallow foundations and friction on the base of the foundations may be considered to provide resistance to lateral forces tending to cause translational sliding. These structural members should be considered for counteracting lateral forces only if the member is placed in directcontact with tested and approved soils. If the foundation is constructed by using forms, lean concrete may be placed between the footing and the undisturbed wall of the adjacent excavation in order to provide the direct contact required to consider passive pressure for counteracting lateral movement. The lean concrete should have a minimum 28-day compressive strength of 1,500 psi. An allowable passive pressure having an URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 4-1 SECTIONFOUR Design Recommendations equivalent fluid density of 250 pcf may be used for design. This is based on a factor of safety of two. An ultimate friction factor of 0.5 for mass concrete on compacted granular fill can be used for design for those portions of the foundations with full positive pressure on the base of the foundation. For foundations placed directly on native clay, an ultimate friction factor of 0.3 should be used. Only long-term dead loads should be considered in calculating the available friction on the foundation base. 4.2.2 Slabs on Grade At the time of this report, the final grades had not been determined. As soon as design slab elevations are known, we should be advised so that we can review and possibly revise the following recommendations. The subgrade under all floor slab areas should be prepared in accordance with Section 4.4. We recommend that floor slabs be underlain by a minimum 6-inch thick granular base course to provide uniformity of support and to act as a capillary break against moisture migration through the slab. The granular base course should consist of a well-graded gravel or crushed rock with a maximum nominal size of 3/4-inch and having less than 5 percent by weight passing the No. 200 sieve. The base course should be compacted to at least 95 percent of its maximum dry density as determined by the modified proctor test (ASTM Test Method D1557). We recommend a modulus of subgrade reaction of 225 pounds per cubic inch (pci) for the base course. Even with a capillary break as outlined above, there is the possibility of some floor moisture or dampness. If floor moisture is a critical consideration due to storage of materials directly on the ofglued down impervious floor coverings such as tile or floor slab, or because of the use p 8 linoleum, we recommend the use of an under-slab impermeable membrane placed directly below the slab. To maximize water tightness, the membrane must be installed in accordance with the manufacturer's recommendations. 4.3 RETAINING WALLS Following are typical design parameters for wall types that we believe represent the range of systems that may be constructed at this site. Please contact us if any additional design values or wall types need to be addressed. 4.3.1 Retaining Wall Design Parameters Lateral soil pressures on a retaining wall depend on several factors including retained soil type, wall fixity, drainage provisions and the influence of surface loads imposed behind the wall. We have provided typical design parameters for wall types that we believe represent the range of retaining wall systems that are likely to be constructed at this site. Our recommendations are based on the following assumptions: URS \\Por6\projects125695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 4-2 SECTIONFOUR Design Recommendations • Retaining walls will be designed to restrain both existing soils and constructed fills. • Retaining walls will be backfilled with free draining crushed rock, in accordance with Section 4.3.4 of this report. • Adequate subsurface drainage will be provided. • Walls will be 12 feet high or less. 4.3.2 Equivalent Fluid Densities Unrestrained walls have no fixity at the top and are free to rotate about their base through tilting or translation. Most cantilever retaining walls fall into this category (unless they are attached to buildings or other structures). A lateral movement of 0.005 times the height of the retaining wall may be required to achieve this active pressure. For these walls, we recommend that a lateral equivalent fluid density of 35 pcf be used for design. Restrained walls are rigid structures where essentially no relative movement occurs between the. structure and the soil. Most basement walls and other rigid walls that are restrained by buildings, parking decks, floor slabs or other perpendicular walls fall into the category of restrained walls. For restrained walls, we recommend that a lateral equivalent fluid density of 55 pcf be used for design. 4.3.3 Additional Lateral Pressures Additional lateral support will be provided by passive resistance of soil compacted adjacent to the sides of the wall foundations. For design purposes, an allowable equivalent fluid density of 250 pcf may be used to estimate the passive resistance. See Section 4.2.1 for additional information regarding construction requirements to realize this passive earth pressure. If cohesive soils are used as backfill, hydrostatic pressures or surcharge effects from surface loads exist, the equivalent fluid density will be significantly higher and URS should be contacted for additional design information. 4.3.4 Retaining Wall Backfill Backfill within 3 feet of retaining walls should consist of free draining crushed rock, free of organics and debris. This material should meet the requirements of the 2002 Oregon Department of Transportation (ODOT) Standard Specifications for Construction for "Granular Wall Backfill", Section 00510.12. Backfill beyond 3 feet from the wall should meet requirements described in Section 4.4.5. We recommend that all fill be compacted to 95% of the maximum dry density as determined by the Modified Proctor test (ASTM 1557). Additionally, we recommend that any backfill that is placed within 5 feet of the wall (measured horizontally) be compacted with lightweight, hand operated compaction equipment. Over-compaction of this fill can increase wall pressures. We recommend the placement of a 4-inch diameter slotted PVC pipe wrapped in non-woven geotextile fabric at the base of the wall backfill to facilitate drainage of this area. URS \\Por6\projectst25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 4-3 SECTIONFOUR Design Recommendations 4.4 SITE PREPARATION 4.4.1 General Prior to construction of any new foundations, all areas that will receive fill, base rock, or structures should be stripped of all surface vegetation, organic topsoil and any deleterious materials that might be encountered. Any soft or unsuitable soils encountered during stripping or excavation should be removed and replaced with compacted structural fill meeting the requirements described in Section 4.4.5. 4.4.2 Dry Weather Earthwork After areas are stripped or excavated to design elevations, we recommend scarification of the resulting subgrade in all areas that will receive fill or structures to a depth of 8 inches. The scarified soil should be brought to 2% above optimum moisture content, and compacted to at least 95 percent of its maximum dry density as determined by ASTM D698, the Standard Proctor method. 4.4.3 Wet Weather Earthwork We anticipate that the native clay found at the site will be susceptible to erosion. Therefore, during or after wet weather, it may be necessary to import granular materials for structural fill or to protect open subgrade materials. It may also be necessary to install a granular working pad to support construction equipment. Delays in site earthwork activities should be anticipated during periods of heavy rainfall. Additionally, site clearing and stripping activities may expose subgrade material that may be damaged if subjected to disturbance from construction traffic. During wet weather, we recommend that site stripping and excavation be performed using an excavator with a straight-edged bucket that does not traverse the final subgrade. When a granular working base is used to protect open subgrade material and construction equipment, the base should consist of a suitable thickness of crushed rock or ballast placed by end-dumping off an advancing pad of rock fill. Areas that contain native alluvium materials are moisture sensitive, and it may be necessary to place a geotextile fabric beneath the working blanket to prevent the intrusion of fines into the rock. Because construction practices can greatly affect the amount of rock required, we recommend that if conditions require the installation of a granular working blanket, the design, installation and maintenance be made the responsibility of the contractor. After installation, the working blanket should be compacted with a minimum of four passes with a smooth-drum roller. 4.4.4 Rock Rippability Rock may be encountered during foundation excavation depending upon the final design and layout of the new school. Site exploration indicated that the depth to weathered bedrock varies from 8 to 16 feet below existing grades. The upper 10 feet of this rock (18-26 feet bgs) is highly weathered and highly fractured. Excavation of the upper portions of this weathered rock (2 to 9 feet) was performed with a Case 9030B excavator and a general purpose bucket. Refusal was UltS \\Por6\projects\25695391 USD Alberta Rider\TtSD Geotech.doc\10-JUL-03 4-4 SECTIONFOUR Design Recommendations typically encountered at about 15 to 20 feet below ground, close to the maximum reach of the excavator. We recommend the use of heavy excavation equipment outfitted with rock buckets to excavate the weathered rock. We do not anticipate the need for blasting or pneumatic breakers to achieve foundation grades. 4.4.5 Structural Fill We recommend that all fills intended to support structures be placed in horizontal lifts not exceeding about 8 inches in loose thickness and be compacted to at least 95 percent of the maximum dry density as determined by the Modified Proctor method (ASTM D1557), unless where specified above. Imported structural fill should be clean, well graded granular material, free of organics and debris and meeting the requirements of the 2002 ODOT Standard Specifications for Construction for "Granular Structural Backfill", Section 00510.13. The procedure to achieve proper density of a compacted fill depends on the size and type of compacting equipment, the number of passes, thickness of the layer being compacted, and certain soil properties. When the size of the excavation restricts the use of heavy equipment, smaller equipment can be used, and the soil must be placed in lifts thin enough to achieve the required compaction. We recommend that methods of compaction be left to the discretion of the contractor, with compaction testing provided by URS. We do not recommend the use of onsite soils for structural fill. This material may be used for miscellaneous fill and landscaping applications around the site provided these areas are not intended to support structures. Onsite soils should be compacted to at least 95% of the maximum dry density per ASTM D698. 4.5 SLOPES Depending on the Contractor's proposed excavation and shoring plan, temporary cut slopes may be required during construction. Cut slope inclinations must be made in accordance with regulations established by the Oregon Occupational Safety and Health Administration (OR- OSHA). In accordance with OR-OSHA, the clay soils in the upper 15 feet of the site are classified as Type B. The maximum allowable slopes for excavation less than 20 feet deep in Type B soils is 1H:1V (Horizontal:Vertical). Flatter slopes will be required if water or seepage is present. Significant slope work is not anticipated at this site. Allowable finished slopes will depend upon the type of fill material that is being used, or the location of any cut slopes. For planning purposes we recommend that any finished cut or fill slopes less than 8 feet high be designed no steeper than 2H:1 V. Onsite fill used to construct slopes or embankments at the site should be compacted per Section 4.5.2. All permanent slopes will require erosion protection. Erosion protection should follow procedures described in the Tigard Community Development Code Chapter 18.745, "Landscaping and Screening". IIRS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 4-5 SECTIONFOUR Design Recommendations 4.6 TEMPORARY SHORING URS does not anticipate the need for temporary shoring for the recommended overexcavation activities. Should shoring be necessary for other parts of the project not described in this report, the Contractor must submit a shoring and excavation plan to the Owner and URS at least 2 weeks before the start of excavation. The plan should show the design of shoring, bracing, sloping, or other provisions to be made for worker protection from the hazard of caving ground and for any trench or excavation over four feet in depth. The shoring and excavation plan must be prepared and stamped by a civil engineer registered in the State of Oregon. 4.7 SEISMIC DESIGN The site lies within Seismic Zone 3 as defined by the 1998 version of the OSSC. Based on the soils encountered during the exploration program, OSSC Soil Type Sc (very dense soil and soft rock) represents the closest approximation to the site conditions and is recommended for use in design. The seismic response coefficients that corresponds with Z=0.3 and Sc are Ca =0.33 and C,,=0.45 and were obtained from tables 16-Q and 16-R of the UBC,respectively. 4.8 CORROSION The corrosion potential of site soils was measured by performing field resistivity tests and laboratory tests for pH, sulfate and chloride content of the samples collected from the site. The four field resistivity test lines are shown on Figure 2. The results of these tests are shown in Table 1. The results of the laboratory tests are shown in Table 2. TABLE 1: MEASURED RESISTIVITY (ohm-cm) Test Line Electrode Spacing 5 10 20 R1 28,400 55,500 155,000 R2 34,500 66,500 143,000 R3 34,300 65,100 132,000 R4 33,400 62,400 140,000 TABLE 2: LABORATORY CORROSION TESTS Test Pit Depth (ft) pH Sulfate Chloride (mg/L) (mg ) TP-3 9 5.4 7.18 0.611 TP-6 4 5.4 5.29 0.585 TP-12 7 5.7 5.56 0.629 The results of these tests indicate that the soils are moderately to mildly corrosive to carbon steel. The risk of sulfate attack on concrete is negligible. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 4-6 SECTIONFOUR Design Recommendations 4.9 PAVEMENT RECOMMENDATIONS We anticipate that vehicle traffic will consist of automobiles, buses, and trucks. Estimated traffic • loads were provided to URS by Ellis Eslick Associates Architects. Additional vehicle loads were estimated for deliveries to the school. Heavy duty pavements are considered to be bus lanes and the entrance road. Light duty pavement is considered for parking areas. TABLE 3: ASSUMED TRAFFIC LOADING Vehicle Type Heavy Duty Light Duty Automobiles 670 vehicles/day 100 vehicles/week day Buses 10 vehicles/day 1 vehicle/week day Heavy Trucks 2 vehicles/week day 1 vehicle/week day Semi-Trucks 1 vehicle/week day 1 vehicle/week day Each vehicle will constitute a single pass over the pavement. Following the AASHTO (1986) procedure, this traffic volume will produce about 310,000 rigid pavement and 285,000 flexible pavement 18 kip equivalent axle loads (EALs) for the bus lanes and 50,000 flexible pavement EALs for the parking areas over the design life of 20 years. This is based on an initial serviceability index of 4.2 and a terminal serviceability index of 2.0. Using the traffic loads described above and a resilient subgrade modulus of 6,000 psi (based on dynamic cone penetration tests), the pavement recommendations shown in Table 4 are recommended. A flexible and rigid heavy duty pavement section were developed. Flexible pavement may be used for the entry driveway to the school. Rigid pavement should be used in the proposed bus circle as the tight radius curves may cause shoving and bleeding to the flexible asphaltic concrete pavement. Table 4: RECOMMENDED PAVEMENT SECTIONS* Section 1 —Heavy Duty (Rigid) 4 in. Portland Cement Concrete; over 10 in. Aggregate Base; over Woven Separation Geotextile; over 8 in. Compacted Subgrade Section 2—Heavy Duty(Flexible) 4 in. Level 2 HMAC; over • 8.in. Aggregate Base; over Woven Separation Geotextile; over 8 in. Compacted Subgrade Section 3—Light Duty(Flexible) 3 in. Level 2 HMAC; over 6 in. Aggregate Base; over Woven Separation Geotextile; over 8 in. Compacted Subgrade *All materials should meet the 2002 ODOT Standard Specifications for Construction. URS \\Por6\projectst25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 4-7 SECTIONFOUR Design Recommendations Areas that are to receive pavement should be stripped and prepared in accordance with the recommendatioi]s in Section 4.4. Stabilizing the subgrade with a woven geotextile separation fabric (meeting the requirements of AASHTO M288-96 Class 2) will maintain segregation of the subgrade soil and aggregate base. If the subgrade soils are allowed to migrate upward into the base course, the result would be decreased pavement support. The aggregate base should conform to the requirements in the 2002 ODOT Standard Specifications for Construction Section 2630 for 1-1/2-in minus material. Aggregate base should be compacted to 95% of the maximum dry density as determined by the modified proctor test (ASTM D1557). We recommend that the hot mix asphaltic concrete and Portland cement concrete conforming to the 2002 ODOT Standard Specifications for Construction be used for all pavements. Minimizing subgrade saturation is an important factor in maintaining subgrade strength. Water allowed to pond on or adjacent to pavements could saturate the subgrade and cause premature pavement deterioration. To avoid this, the pavement should be sloped to provide rapid surface drainage, and positive surface drainage should be maintained away from the edge of the paved areas. Design alternatives that could reduce the risk of subgrade saturation and improve long- term pavement performance include crowning the pavement subgrade to drain toward the edges, rather than to the center of the pavement areas; and installing surface drains next to any areas where surface water could pond. Properly design and constructed subsurface drainage will reduce the time subgrade soils are saturated and improve subgrade strength and performance. 4.10 ATHLETIC FIELD RECOMMEDATIONS The native soil below the proposed play fields is entirely composed of clay. This material is estimated to have an infiltration rate of about 0.05 inches/hour (U.S. Soil Conservation Service, 1986). We recommend the placement of a drainage fill below the play field surface due to the poor drainage characteristics of the native soils at the site. Drainage fill should consist of free- draining sand or gravel with less than 5% passing the No. 200 sieve. The subsurface drainage system should be designed with a conveyance scheme to remove water that collects at the interface between the drainage fill and the native clay soils. Construction of the new play fields should be performed in accordance with the recommendations presented in Section 4.4. URS recommends that construction take place during the dry season to aid in the prevention of contamination of the drainage fill with fines from the underlying clay. Drainage fill should be placed in horizontal lifts no greater than 10 inches in thickness and compacted to a minimum of 92% of the maximum dry density as determined from the Modified Proctor test (ASTM D1557). For play field surfaces designed and constructed as specified in Section 4.4, we estimate settlements will be negligible. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 4-8 SECTIONFIVE Sensitive Site Status Tigard Community Development Code Section 18.775 defines "sensitive" sites that may be unsuitable for development. Included in the definition of sensitive sites are locations where existing slopes exceed 25%. Existing slopes at the site approach 25% at the northwest edge of the site, but no new facilities are planned in this area. Slopes in the area of the new structure are generally less than 10%. Further, the proposed site plan meets the acceptance criteria for sites built in areas with slopes greater than 25%, outlined in Section Tigard Community Development Code Chapter 18.775.070.C. These criteria are as follows (description of the site compliance is provided in italics): 1. The extent and nature of the proposed land form alteration or development will not create site disturbances to an extent greater than that required for the use; - The proposed school and appurtenant facilities will disturb only their immediate footprints. These disturbances will not affect the stability of the site. 2. The proposed land form alteration or development will not result in erosion, stream sedimentation, ground instability, or other adverse on-site and off-site effects or hazards to life or property; - Proper restoration of the site will ensure no erosion and stream sedimentation will occur. Structures constructed per the recommendations in the report will not adversely affect ground stability. 3. The structures are appropriately sited and designed to ensure structural stability and proper drainage of foundation and crawl space areas for development with any of the following soil conditions: wet/high water table; high shrink-swell capability; compressible/organic; and shallow depth-to-bedrock; and - Structures designed and constructed with the parameters and recommendations described in this report will be stable and provide adequate drainage. Refer to Sections 4.2 through 4.5. 4. Where natural vegetation has been removed due to land form alteration or development, the areas not covered by structures or impervious surfaces will be replanted to prevent erosion in accordance with Chapter 18.745,Landscaping and Screening. -Project specifications must contain a section regarding site restoration insuring the finished site meets the requirements of Chapter 18.745. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 5-1 SECTIONSIX Construction Monitoring We recommend that URS be retained to provide construction monitoring and testing services during earthwork activities and foundation construction. The purpose of our field monitoring services is to confirm that site conditions are as anticipated, to provide field recommendations as required based on conditions encountered, and to document the activities of the contractor to assess compliance with the project recommendations provided by URS. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 6-1 SECTIONSEYEN Closure The analyses, conclusions and design recommendations presented in this report are based on site conditions as they existed at the time of our field exploration, and further assume that the conditions encountered are representative of subsurface conditions within the study area. If conditions different from those described in this report are encountered or appear to be present beneath excavations, URS should be advised at once so that additional recommendations may be provided where necessary. This report was prepared for the exclusive use of the Tigard-Tualatin School District and its agents and consultants. It should be made available to prospective contractors for information on factual data only and not as a warranty of subsurface conditions similar to those interpreted from the borehole logs or discussions presented in this report. URS \\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 7-1 SECTIONEIGHT References American Association of State Highway and Transportation Officials, 1986. AASHTO Guide for Pavement Structures, AASHTO, Washington D.C. Deere, D.U., and Deere, D.W., 1989. The Rock Quality Designation (RQD) in Practice, in Rock Classifications Systems for Engineering Purposes. Ed. Louis Kirkaldie, ASTM STP 984, Philadelphia: American Society for Testing and Materials,pp. 91-101. Malin, I.P. (1990). Earthquake Hazard Geology Maps of the Portland Metropolitan Area, Oregon. Oregon Department of Geology and Mineral Industries (DOGAMI), Open-File Report 0-90-2. Oregon Department of Transportation, 2002. Oregon Standard Specifications for Construction, Salem, Oregon. Orr, E.L., Orr, W.N. and Baldwin, E.M., 1992, Geology of Oregon, Fourth Edition, Kendall/Hunt Publishing Company,Dubuque, Iowa. U.S. Soil Conservation Service, 1986. Technical Release 55: Urban Hydrology for Small Watersheds,U.S. Department of Agriculture. Unruh, J.R., Wong, I.G., Bott, J.D.J., Silva, W.J., and Lettis, W.R., 1994. Seismotectonic Evaluation: Scoggins Dam, Tualatin Project, Northwestern Oregon; William Lettis & Associates and Woodward-Clyde Federal Services, unpublished final report prepared for the U.S. Bureau of Reclamation, Denver, CO. Wells, R.E., Weaver, C.S., and Blakely, R.J., 1998. Forearc Migration in Cascadia and its Neotectonic Significance: Geology, v. 26, p. 759-762. Winterkom, H.F., and Fang, H-Y., 1975. Foundation Engineering Handbook, Van Nostrand Reinhold Company, N.Y., N.Y. URS \\Por6\projects\25695391 TTSD Alberta RiderITTSD Geotech.doc\10-JUL-03 8-1 III! L7JiN �a• '¢ r" // -kyy. „ t ,' u -'' 'ilk r , ▪ f syr t •. . T — — � _ 154 . .dry ,y r c( f . II' '�- _ / _ Q.Wtalec 3"y ,,-•• -.� �� , _ { • *� r' k K i { {i 144 /. 1 v 2,,, y \ ,,, .,,_,5/__,..„.,. ..z.,:,. 7 . =r` `-� � — - , ,r I- Yom, ..__ \ ._ ( i 4Il °r'1 r.. `rJ y r '��$ I • --, i -� 'l r`\ �,:- ,� (t M _ rT 111111 � :' r(1 1 • \e '' .,{�F"., r�`'- "� T�.,y�t' t - - • -• ";-;--% r!i {" fi Ili l y . _. _tf1 i A � 1-7,,,,--_-__./i,.,!.� it•`' t (i # T — /i�_ air y5ti Ij� rr > l$p� i2kiii ,- .-- � vT, � ijtitAAr-_g= i . ` %'Y �r :.--;—‘9'rt— r ley: i M e �_' 1 i 1 '''.,-i:!:1 .� y.!! ft`-°°--/I:°;6I ] 1 s ( y ' _ ,. B 14u 1 SOURCE:SALEM WEST. OREGON uses TOPOGRAPHIC QUAORAHtxE ,986 . , 1 g . VICINITY MAP TTSD Alberta Rider Elementary School i luiltS July 2003 Geotechnical Investigation 25695391 Tigard,Oregon FIGURE 1 a 3' GRANULAR WALL BACKFILL (SEE NOTE 2)---\;)0000a \y1/��y >OoOo V 00o 3000 > o o 0 oo -STRUCTURAL FILL- >°°°° (SEE NOTE 4) 0 0 >o o 0 >o°o°, CONSTRUCTION 0000 CUT SLOPE 1H:1V 0 0 Q >00001 0000 >°000 >°000 >0000 >°000` VAPOR BARRIER >°o°o' CLAY e FLOOR SLAB : q; �. >°o°o GRANULAR BACKFILL(SEE NOTE 3) . >0 0 0 0 Y///>\ \'//AU'" > Oo° FOOTING > 00 CLAY OR WEATHERED BASALT 4"PERFORATED PIPE WRAPPED IN FILTER FABRIC (SEE NOTE 1) NOTES: 1. FILTER FABRIC TO BE NON-WOVEN GEOTEXTILE SUCH AS LINQ 40EX,MIRAFI 140N,OR EQUIVALENT. 2. GRANULAR WALL BACKFILL TO MEET REQUIREMENTS OF THE 2002 ODOT STANDARD SPECIFICATIONS FOR CONSTRUCTION,SECTION 00510.12. GRANULAR BACKFILL SHOULD BE PLACED WITHIN 3 FEET OF THE WALL. 3. GRANULAR FILL TO CONSIST OF CLEAN,WELL-GRADED,3/4"MINUS DIAMETER CRUSHED ROCK AND SAND CONTAINING LESS THAN 5 PERCENT PASSING THE NO.200 US STANDARD SIEVE. 4. STRUCTURAL FILL TO MEET THE REQUIREMENTS OF THE 2002 ODOT STANDARD SPECIFICATIONS FOR CONSTRUCTION,SECTION 00510.13. 9 4 Y STANDARD SLAB&WALL DRAINAGE DETAIL TTSD Alberta Rider Elementary School ° 1URS July 2003 Geotechnical Investigation 25695391 Tigard,Oregon FIGURE 3 2 APPENDIX A Subsurface Exploration Logs URS0:\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 Project: TTSD Alberta Rider Elementary School Key to Log of Boring Project Location: Tigard, Oregon Project Number: 25695391.10001 SAMPLES IM o0 O J 0 CD .7 �, =n r s m� MATERIAL DESCRIPTION REMARKS AND mm ami aa� E E 3 ° a oU m`.c°t o OTHER TESTS I- Z COCC CO M (.! JU 0- El 1❑ 2 ❑3 4 5 © 7 ® 9 10 11 12 COLUMN DESCRIPTIONS 1 Elevation:Elevation in feet referenced to mean sea level 8 Lithologv Loq:Unified Soil Classification Code(USCS)for (MSL)or site datum. corresponding lithologic unit. nDepth: Depth in feet below the ground surface. n Material Description: Description of material encountered; may include color,moisture,grain size,and density/consistency. n Sample Type: Type of soil sample collected at depth interval shown;sampler symbols are explained below. 10 Water Content: Water content of soil sample measured in laboratory,expressed as percentage of dry weight of specimen. 4 Sample Number: Sample identification number. 11 Percent Passing#200 Sieveercentage of sample passing the 5 Sampling Resistance: Number of blows required to advance #200 sieve by weight. driven sampler 12 inches beyond first 6-inch drive interval,or distance noted,using a 140-lb hammer with a 30-inch drop; 12 Remarks and Other Tests:Comments and observations hydraulic down-pressure for tube sampler. regarding drilling or sampling made by driller or field personnel. Other field and laboratory test results,using the following Recovery: Percentage of driven or pushed sample length abbreviations: recovered;"NA"indicates data not recorded. 7 Graphic Loq: Graphic depiction of subsurface material encountered;typical symbols are explained below. TYPICAL MATERIAL GRAPHIC SYMBOLS x..x. j Lean Clay fx%'" Basalt x x x XX TYPICAL SAMPLER GRAPHIC SYMBOLS OTHER GRAPHIC SYMBOLS N • Dames&Moore Type U 11 NX Wireline Coring E, s Jl 0 a m Soil classifications are based on the Unified Soil Classification System.Descriptions U and stratum lines are interpretive;field descriptions may have been modified to reflect lab test results. Descriptions on these logs apply only at the specific boring locations and at the time the borings were advanced;they are not warranted to be o representative of subsurface conditions at other locations or times. oi0 Q URS Project: TTSD Alberta Rider Elementary School Key to Log of Boring Project Location: Tigard, Oregon Project Number: 25695391.10001 KEY TO DESCRIPTIVE TERMS USED ON CORE LOGS DISCONTINUITY DESCRIPTORS na Dip of discontinuity,measured relative to a plane normal to the core axis. nDiscontinuity Type: Ee Amount of Infilling: F - Fault Su - Surface Stain J - Joint Sp - Spotty Sh - Shear Pa - Partially Filled Fo - Foliation Fi - Filled ✓ - Vein No - None B - Bedding nc Aperture(inched: n Surface Shape of Joint: W - Wide (0.5-2.0) PI - Planar MW - Moderately Wide (0.1-0.5) Wa - Wavy N - Narrow (0.05-0.1) St. - Stepped VN - Very Narrow (<0.05) Ir - Irregular T - Tight (0) nType of Infilling: n Roughness of Surface: CI - Clay Slk - Slickensided [surface has smooth,glassy finish with visual Ca - Calcite evidence of striations] Ch - Chlorite S - Smooth [surface appears smooth and feels so to the touch] Fe - Iron Oxide SR - Slightly Rough [asperities on the discontinuity surfaces are Gy - Gypsum distinguishable and can be felt] H - Healed R - Rough [some ridges and side-angle steps are evident;asperities Mn - Manganese Oxide are clearly visible,and discontinuity surface feels very abrasive] No - None VR - Very Rough [near-vertical steps and ridges occur on the Py - Pyrite discontinuity surface] Qz - Quartz Sd - Sand ROCK WEATHERING/ALTERATION Description Recognition Residual Soil Original minerals of rock have been entirely decomposed to secondary minerals,and original rock fabric is not apparent;material can be easily broken by hand Completely Weathered/Altered Original minerals of rock have been almost entirely decomposed to secondary minerals, g although original fabric may be intact;material can be granulated by hand oHighly Weathered/Altered More than half of the rock is decomposed;rock is weakened so that a minimum 2-inch-diameter sample can be broken readily by hand across rock fabric Moderately Weathered/Altered Rock is discolored and noticeably weakened,but less than half is decomposed;a minimum 2-inch-diameter sample cannot be broken readily by hand across rock fabric Slightly Weathered/Altered Rock is slightly discolored,but not noticeably lower in strength than fresh rock Fresh/Unweathered Rock shows no discoloration,loss of strength,or other effect of weathering/alteration • ROCK STRENGTH O Description Recognition LL Extremely Weak Rock Can be indented by thumbnail • Very Weak Rock Can be peeled by pocket knife Weak Rock Can be peeled with difficulty by pocket knife Medium Strong Rock Can be indented 5 mm with sharp end of pick Strong Rock Requires one hammer blow to fracture Very Strong Rock Requires many hammer blows to fracture Extremely Strong Rock Can only be chipped with hammer blows ctU O URS Project: TTSD Alberta Rider Elementary School Log of Boring B-01-2003 Project Location: Tigard, Oregon Project Number: 25695391.10001 Sheet 1 of 2 Date(s) 6/13/2003 Logged JDS Checked BJD Drilled By By Drilling HSA/Wireline Core Drill Bit 4 1/4"I.D.Auger,NX-Core Total Depth 29 0 FT Method Size/Type of Borehole Drill Rig CME 75 Drilling Geo-Tech Explorations,Inc. Approximate -568.0 feet MSL Type Contractor Surface Elevation Groundwater Level Not Encountered Sampling D&M Hammer 300 Ib and Date Measured Method(s) Data Borehole Bentonite Chips Location See Figure 2,Site Map Backfill SAMPLES rn 0,,....„ D o t C O -1'O N m �, _ r m� MATERIAL DESCRIPTION92 - .-rn REMARKS W2 C1a T 7 NN0 OC a '0...c 5o NN4' I- Z MCC a3 CC:.7.-- 0 J2 20 a.n.v 0- / CL -LEAN CLAY[CL]low plasticity,rapid dilatancy,micaceous,trace - - organics,mottled,medium stiif,brown,moist. 2- - - 1 -565 - - - - 4- / - - - - ■ -111 1 7 18 6—� / — — j - -560 8— / — — 10 - - ■ Grades to medium plasticity,no dilatancy,trace basaltic gravel, O / - stiff,reddish brown,moist. _I 2 13 18 / _ • - ■ g ci m 12— — — m N -555 - - - .... ..xxxx Basalt BASALT highly to extremely weathered,veryweak,highly @ 13.5'Driller notes d 14- •xxxx -fractured,Fe,Mn,Cl filled fractures,<5%vesicles>2mm in dia., - less cohesive,more C7 ,xxx xxx _ grayish red brown,moist. _ granular[less :J xxxxx weathered] - - m . ."xxxxx O x x x x x x 3 52 18 xxx xxx x 16 -.xxxx - - iL • ,..xxxx ,..xxxx - p x x x N - 'xxx xxx iF (.J _ xxxx _ xx • x • o-550 18- `xxxxxx .-- - o - .xxx. - - �� - •xxxx - - H ,xx a 20 - Project: TTSD Alberta Rider Elementary School Log of Boring B-01-2003 Project Location: Tigard, Oregon Project Number: 25695391.10001 Sheet 2 of 2 SAMPLES O U C J �O o N �'al`" z . O MATERIAL DESCRIPTION 2.-7..m REMARKS N L �r a> U 0) >.-. 75.- .0 C O ifn y > L O .=..N N C W 41 o E E'in o c�i-� N Y� y c e 2> >- = ay N 0 d O O d cd._ 20 t— Z MC[m CC 0 _,z �O C_am ■ : xxx Basalt BASALT highly to moderately weathered,moderately strong to • -I 4 50-5" 11 .xxxxxx - strong,highly fractured,Fe,Mn,CI filled fractures,5-10%vesicles - .• xxxxxx _<2mm in dia.,trace phenocrysts,brownish gray. 'xxxxxx CORE RUN 1 -21-25.25 ft 100%Recovery,RQD 9%,greater than Begin NX-Coring - x ' x xx x - 10 fractures per foot. - .x x xx x x 22- x x x - - x x x < x x x x x x z x x x x IXXX -545 - 5 51 xxxxxx - - x x x x x x x x x x x x 24- ,xxxxxx - - -.- ,xxx xxx x x x - x x x x x x x x x - - . . x - xxxxxx - Grades to moderately to slightly weathered,strong,moderately - xx fractured,trace vesicles>2mm in dia.trace plagioclase 26- •xxxxxx -phenocrysts. - •xxxxxx _ CORE RUN 2-25.25-29 ft 100%Recovery,ROD 32%,5 to>10 _ <xxxxxx - 6 43 <xxxxxx - - x x x x x x x x x -540 28- xxxxxx - - <xxxxxx x x xxx x — x x x Boring terminated at a depth of 29.0 feet bgs on 6/13/2003 and - backfilled with bentonite chips upon completion. - 30- - - 32- - - -535 - - - • 34J - - m 0 - - 0 N s 36- - - m m 0 a-530 38- - - _J fA O COAi 40- - - IL _ O N o _ _ nI - - 0 42- 0 o - 0-525 - - - cc 0 a o0 a o Project: TTSD Alberta Rider Elementary School Log of Boring B-02-2003 Project Location: Tigard, Oregon Project Number: 25695391.10001 Sheet 1 of 2 Date(s) 6/13/2003 Logged Checked Drilled By JDS B BJD Drilling Drill Bit Y Method HSA/Wireline Core Size/Type 41/4"I.D.Auger,NX-Core Total Depth 31.0 FT Ype of Borehole Drill Rig CME 75 Drilling Approximate Type Contractor Geo-Tech Explorations,Inc. Surface Elevation -561.0 feet MSL Groundwater Level Not Encountered Sampling D&M Hammer 300 lb and Date Measured Method(s) Data Borehole Bentonite Chips Location See Figure 2,Site Backfill 9Map SAMPLES E. 0-.Eo o-8 0 co.. o.� Q N 2 cm 6 t o MATERIAL DESCRIPTION 2 m REMARKS w92 o a E � 0o 0c m oo w�a 0 I- z UM 03 CC z.. 0 �? � o i a..v CL LEAN CLAY[CU low plasticity,rapid dilatancy,trace organics, - mottled,micaceous,medium stiff,brown,moist. -560 - _ - 2- - - 4- - - 1 - -555 6:_11114.1] 6 i s j - - 30.7 98.7 _ - 8- - - - - _ 10 ■ - Grades to medium plasticity,no dilatancy,some angular basaltic ■ - gravel,stiff,reddish brown,moist. - -550 -■ 2 12 18 - _ 27 91.2 o ■ 0 - O 12- - - Driller notes harder m drilling CO 11.5'-13.5', softer between 13.5' 0 - to 15.0'bgs bgs g 14- - _ j - 0 . ,, x xx Basalt BASALT extremely to highly weathered,extremely weak,highly ■ 3 13 18 ,xxxxx fractured,CI,Mn,Fe filled fractures,<5%vesicles>2mm in dia., -545 16-1 x x x reddish brown,moist. m , x x x - it x x O xxx xxx xx o x x x N - %x%xx - - aI U - 2 xxx O 18- xxxxxx - - oxxxxx Increased drilling xxxx x resistance 18 - 1--Ixxxxx - _ Q O xxxx - a. xx xxx 20 . _ O n Project: TTSD Alberta Rider Elementary School Log of Boring B-02-2003 Project Location: Tigard, Oregon Project Number: 25695391.10001 Sheet 2 of 2 SAMPLES rn-- m C ai d co J o o 0 ro .__ a,r �� MATERIAL DESCRIPTION ;v ._.tn REMARKS >.... n..-, auvi > s oW o cc W pow a = romp me ._ t_, oo mea I- Z Cf)CC CO CC. a J- U O..CL v . 20 ■ xxxxxx Basalt BASALT highly weathered,very weak,highly fractured,Cl,Mn, ■ 4 30 18 `xxxxxxx - Fe filled fractures,<5%vesicles>2mm in dia.,reddish brown, - x x _moist. —540 —■ x z x — ■ •x x x x xx x x xxxx - , x x x xx x 22— . x x z — — x x x x x x x z x z x x �x x x _ x z x x x x xxx - x x x x x x xxxxxx _ x x x 24— xxx — — xxxxxx x x VV.' z x x x x , x x x x x x xxxxxx — ■ 5 50-4" 10 ,xxxxxx —535 26--- xxxxxx Grades to moderately weathered with highly weathered fracture Begin NX-Coring - ,xxxxxx - zones,weak to moderately strong,trace vesicles>2mm in dia., - .xxxxxx trace phenocrysts,fractures are filled with Cl,Mn,Fe,brownish — ,xxxxxx —gray. - .xxxxxx _ CORE RUN 1 -26-31 ft:96%Recovery,RQD 0%,>10 fractures _ x x x per foot. 28— xxxxxx —Contains several high angle,clay filled fractures — x x x - 6 58 ,xxxxxx - - x x x xxxxxx — , x x x ,xxxxxx x x x - _ xxxxx 30— , xxx — — x x _ .xxxxxx _ xxxxx —530 — x x x Boring terminated at a depth of 31.0 feet bgs on 6/13/2003 and - - backfilled with bentonite chips upon completion. - 32— — — 34— — — M N o—525 36— — — co __ _ co 0 cj d 38— — — c1 J m 0 ca - r 40— — — 1 ir. _ o—520 — — — ft 2� — O 42— — 0 o - w 1- cc0 a . r 0 n URS 1 Project: TTSD Alberta Rider Elementary School Log of Boring B-03-2003 Project Location: Tigard, Oregon Project Number: 25695391.10001 Sheet 1 of 2 Drlled) 6/13/2003 Logged JDS By Checked BJD Drilling HSA/Wireline Core Drill Bit 41/4"I.D.Auger,NX-Core Total Depth 30.0 FT Method Size/Typeof Borehole DrillRigCME 75 DriContractor Geo-Tech Explorations,Inc. Approximate -562.0 feet MSL TypeSurface Elevation Groundwater Level Not Encountered Sampling D&M Hammer 140 Ib and Date Measured Method(s) Data Borehole Bentonite Chips Location See Figure 2,Site Map Backfill SAMPLES my c ai. o a o 0 fa o 411 z .6 0)2 cm a) En0 MATERIAL DESCRIPTION ;v rn REMARKS w� CD CI)04L2 a E Ev, o ca)--. m LU) "'c �N> > mai � c ] oo 0Na 0 I- Z v)CCC CC U .j 2U a.o_a CL -LEAN CLAY[CU low plasticity,rapid dilatancy,micaceous,trace - organics,mottled,stiff,brown,moist. -560 2- / - - 4- / - - _ ■ 18 18 / -Grades to medium plasticity,no dilatancy,trace basaltic gravel, ■ - stiff,reddish brown,moist. 1 • - -555 - . - - 8- - - 10 ill xxxxxx Basalt BASALT extremely weathered,extremely to very weak[hard], 2 67 18 ,xxx,x. - highly fractured,remant vesicles,reddish brown,moist.x x x - , x x x Ocxxxx p x x x - N , x x x x x o-550 12- cxxx - - :xxxxxx xxxxx xco - - 0 c x x x N x xx - - -xxxxx xxx a 14- .xxxx - - c5 - -xxxxx - - c x x 0 xI:0 xxxxxx _ _ O j 3 106-6" 12 xxxxxx Grades to highly weathered, weak to very weak,highly fractured, - Fe,Mn,CI filled fractures,5-15%vesicles>2mm in dia.,grayish red- _ 16 -brown. 1 xxxxx - U. xxx O - - RI- 545 - ,xxxx - - xxxx O , x x m ,xxxxx 01 18- ,xxxx - - Q x x 1 O - - W xxxx x xxx � ' 4 100-4" .33 xxxxxx Grades to highly to moderately weathered, weak to moderately Driller notes a xxxxxX strong,<5%vesicles>2mm in dia.,grayish brown. significant resistance r 20 - 0 0. ct URS Project: TTSD Alberta Rider Elementary School Log of Boring B-03-2003 Project Location: Tigard, Oregon Project Number: 25695391.10001 Sheet 2 of 2 SAMPLES o m � y'C O J o \O N .c _ r m� MATERIAL DESCRIPTION m.- rn REMARKS —� out LT,2 a.92 o. E E 0 o c0i^ Es .c CU!) - o= a)N a � 7 (0 N N C O N ftl._ 20 I— Z u)CCm CC c'3 J MO o_a.va xxxxxx Basalt BASALT moderately weathered,weak to moderately strong, Begin NX-Coring - xxxxx - highly fractured,5%vesicles>2mm in dia.,grayish brown. - xxxxxxx CORE RUN 1 -25-30 ft:89%Recovery,ROD 0%,>10 fractures _ -xxxxxx —per foot. IX x X x x - • - . x XX XX x —540 22— x x x — — ,xxxxxx Moderately to highly weathered zone 22'to 22.5'bgs - 5 60 xxxxxx - - x x x X XX - IX XX - - X XX CX x - xxxxxx - - x x x 24- xxxxxx - - x x x Driller notes softer x x x - .xxxxxx - - drilling between _ 24'-25' :xxxxxx Grades to weak,highly fractured,highly weathered lens<6"thick _ • - ,xxxxxx - from 25'to30'bgs. - 26— `xxxxxx .-CORE RUN 2-25-30 ft: 50%Recovery,RQD 0%,>10 fractures — xxxxxx per foot. x x x x x x x xx - - —535 — 'xxxxxx — — z x x - 6 30 'xxxxxx - - x x x 28— x xxxx — xxx x txxx - xxxxxx - - x x x 'xxxxx _ - x x x x x x xxxxxx - - . x x x 30 — xxxxxx - Boring terminated at a depth of 30.0 feet bgs on 6/13/2003 and - - backfilled with bentonite chips upon completion. - —530 32— — — 34— — — m g - - N a 36— — — m 8—525 — — — a 38— — — P - - _ _ m r 40— — — io O — O — — N ft U oI—520 42— — — a 0 w ED — — — 1- cc 0 a 0 c Project: TTSD Alberta Rider Elementary School Key to Log of Test Pit Project Location: Tigard,Oregon Project Number: 25695391.10001 • rn a) a) a>iu REMARKS AND MATERIAL DESCRIPTION N w o OTHER TESTS a.) a) as CD as as 0 0 a)o WJ o.9. co foZ C9 �U a`t 1 2 3❑ 4 11l 6 7 8 9 COLUMN DESCRIPTIONS 1 Elevation: Elevation in feet referenced to mean sea level 6 Material Description: Description of material encountered; (M5L)or site datum. may include color,moisture,grain size,and density/consistency. 2 Depth: Depth in feet below the ground surface. 7 Moisture Content, /o Moisture content of sample. 3 Sample Type: Type of soil sample collected at depth interval shown;sampler symbols are explained below. 8 Precent Passing#200 Sieve Precentage of sample passing the #200 sieve by weight. 4 Sample Number: Sample identification number. 9 Remarks and Other Tests: Comments and observations 5 Graphic Log: Graphic depiction of subsurface material regarding excavation or sampling made by driller or field encountered;typical symbols are explained below. personnel. Field and laboratory test results(other than water content), using abbreviations explained below. TYPICAL MATERIAL GRAPHIC SYMBOLS r/ALean Clay x%%.%% Basalt TYPICAL SAMPLER GRAPHIC SYMBOLS OTHER GRAPHIC SYMBOLS �, SSSS Disturbed Sample 0 11 N a r 0 0 N a TYPICAL LABORATORY TEST ABBREVIATIONS 0 0. J J Soil classifications are based on the Unified Soil Classification o System.Descriptions and stratum lines are interpretive;field • descriptions may have been modified to reflect lab test results. Descriptions on these logs apply only at the specific test pit locations LL and at the time the test pits were excavated;they are not warranted to be representative of subsurface conditions at other locations or times. 0 0 N 0 U Y W a i- 0 a 0 a Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-01-2003 Project Number: 25695391.10001 Date(s) 6/4/2003 Logged JDS Checked BJD Excavated By By Length of Width of Depth of Excavation 15.0 feet Excavation 3.0 feet Excavation 15.0 feet Excavation Case 9030 B Trackhoe Excavation BEC Approximate .-571.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface Grassy Field Condition • rn a) c Q O) h co 0 O F— J o CL > .2 -e a) a) g ;v-. a� REMARKS AND • >w, a., a T1_0 :E MATERIAL DESCRIPTION = iu .o OTHER TESTS LDmw � m E E E Nc El 0 CO cou)Z C9 �U Q 4, 0 j LEAN CLAY[CL], low plasticity,trace organics,medium stiff,brown, moist. —570 - • � - 5— % — • Increase in moisture content,mottled. Grades to medium plasticity,trace angular basaltic gravel,stiff,reddish brown,moist. j x BASALT,highly weathered, highly fractured,very weak,moist. - xxx xxxExcavator notes difficult . xxx xxxxxx excavation. 10— xxx_ x — x xxxx• ,xx xx —560 ` x xxx Grades to highly to moderately weathered,weak Cl, xxx- - o . X x N xxx xxx p x z O. - - .xxxxxx M O O - � X X xxx o 15 XX xx Test Pit terminated at a depth of 15.0'bgs on 6/4/2003 due to hard O excavating conditions. J J m m 0 - - - `- m it - - O .6 0 I 0. t-I 20— — — 1- re O a—550 0 n K Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-02-2003 Project Number: 25695391.10001 'Date(s) 6/4/2003 Logged SDS Checked BJD Excavated By By Length of 15.0 feet Width of 3.0 feet Depth of 19.5 feet Excavation Excavation Excavation Excavation Case 9030 B Trackhoe Excavation BEC Approximate -.558.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface GrassyField Condition o) c fl. rn 'w O F- J (11 > -- a) a) a� , a REMARKS AND >— 0. n. Q.o c MATERIAL DESCRIPTION 'v, -1), ami ) 6 E E E m —•, u O OTHER TESTS — �w CO 0 c o �O a4 0 % LEAN CLAY[CL], low plasticity,rapid dilatancy,trace organics, micaceous,medium stiff,brown,moist. 1 31.7 96.8 5— — _ 7 - —550 - - Grades to medium plasticity,slow dilatancy,trace angular gravel,stiff, reddish brown,moist. 10--- — 2 28.4 87.1 g N R H OjO _ a 15— - �D x BASALT,highly weathered,very weak,highly fractured,5-10%vesicles 2 x >2mm dia.,Fe,Cl, Mn filled fractures,moist. - J 0 -03 xxx x - m xx ®. Grades to highly to moderately weathered,weak to moderately strong LL-540 - - a. o d1 x x xx Test pit terminated at a depth of 19.5'bgs on 6/4/2003 due to difficult -.. 20— —excavation last 2.0'. — ix 0 0. 0 8- Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-03-2003 Project Number: 25695391.10001 Excaysated 6/4/2003 Logged JDSBy Checked y BJD Length of 15.0 feet Width of Depth of Excavation Excavation 3.0 feet Excavation 19.5 feet Excavation Case 9030 B Trackhoe Excavation BEC Approximate Equipment Contractor Surface Elevation 559.5 feet MSL Water Groundwater Not Encountered Observations Weather Sunny,80's Location See Figure 2,Site Map Surface GrassyField Condition 0) a) c O>, ni a > >•, n.• o. a1 s MATERIAL DESCRIPTION �' a °-' REMARKS AND 92 ea) E EE o OTHER TESTS W.G taw !AZ C7 LP N 0 O 0 , �U o- LEAN CLAY[CL],low plasticity,rapid dilatancy,trace organics, micaceous,medium stiff,brown,moist. 5— 7 Grades to medium plasticity,no dilatancy,trace angular basaltic gravel, stiff,reddish brown,moist. 77�� 1 pH=5.4,Sulfates= 7.18 mg/L,Chlorides= —550 0.611 mg/L 10— Basaltic clasts increase o o Q j o /m :� a. 15— xxxxxx BASALT,highly weathered,very weak,highly fractured,5-10%vesicles x >2mm dia.,Fe,CI,Mn filled fractures,reddish brown. 2 - - m 0 - xxxxxx xxxxxxxx Grades to highly to moderately weathered, weak to moderately strong x x m O xxx —540 x x x a' Test Pit terminated at a depth of 19.5'bgs on 6/4/2003 due to hard ~� 20— —excavating the last 2.5'. — K URS 0 - 0 Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-04-2003 Project Number: 25695391.10001 ExcavatedDates6/4/2003 Logged JDS Checked BJD Y By Length of Width of Depth of 15.0 feet 16.5 feet ExcavationExcavation 3.0 feet Excavation Excavation Case 9030 B Trackhoe Excavation BEC Approximate Equipment Contractor Surface Elevation —559.0 feet MSL Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Slte Map Surface GrassyField Condition C c c O T O v1 F- JN N >.- -- a a.n 9 MATERIAL DESCRIPTION REMARKS AND w w E E E -, `o OTHER TESTS to Z 0 0 a o �U a.4i 0 LEAN CLAY[CL],low plasticity,rapid dilatancy,trace organics,medium stiff,mottled brown,moist. 1 5— —550 Grades to medium plasticity,slow dilatancy,trace angular gravel,stiff, mottled reddish brown,moist. 10- 0 o Increase in basaltic gravel 04- 0 o o _ % BASALT,highly weathered,very weak, highly fractured,5-10%vesicles % >2mm dia.,reddish brown,moist. a.o 15— % Grades to highly to moderately weathered,weak to moderately strong 2XXX% - % X' o % Test Pit terminated at a depth of 16.5'bgs on 6/4/2003 due to hard excavating through the last 2.0'. - m O O 4,—540 - - 0 CL 20—re — — H 0 O a 0 0 m • Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-05-2003 Project Number: 25695391.10001 Date(s) Logged Checked Excavated 6/412003 By JDS By BJD Length of Width of Depth of Excavation 15.0 feet Excavation 3.0 feet Excavation 16.5 feet Excavation Excavation Approximate Equipment Case 9030 B Trackhoe Contractor " 556.5 feet MSL BEC Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface Grassy Field Condition • co N 0 CO — -J o co xU >., a-, Q s MATERIAL DESCRIPTION =w a REMARKS AND ar) d2 E EE m �,c o OTHER TESTS Da) 02 coN coa)Z C7 2cO a4E 0 % LEAN CLAY[CL],low plasticity,rapid dilatancy,micaceous,trace organics,medium stiff,mottled,brown,moist. 1 29.4 96.4 5— — Increase in moisture content —550 10 2 Grades to medium plasticity,slow dilatancy,some angular basaltic gravel, 27.4 84.2 stiff,mottled,reddish brown. 0 - N 9 / a A . xxxxxx BASALT,highly weathered,very weak,highly fractured,5-10%vesicles oxxxxxx >2mm dia.,Fe, Mn,Cl filled fractures,reddish brown. O N - xxxxxx a. 15— xxxxxx Grades to highly to moderately weathered, weak to moderately strong ra xxx I- xxx _ _ o—540 Test Pit terminated at depth of 16.5'bgs on 6/4/2003. 0 G , a- a N .. 0 2 a. 1i 20— — — F K 0 a c 0 K Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-06-2003 Project Number: 25695391.10001 Date(s) 6/4/2003Logged JDS Checked Excavated By By BJD Length of 15.0 feet Width of 3.0 feet Depth of Excavation Excavation Excavation 19.0 feet Excavation Case 9030 B Trackhoe Excavation BEC Approximate -568.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface GrassyField Condition 0) a) c c O >' 0 ch `a °' 1.0 " MATERIAL DESCRIPTION , a REMARKS AND "� w a) E E ' 8 Q OTHER TESTS W Ow v`°) v)Z U 0 0 wo 0 MO a4 jLEAN CLAY[CL],low plasticity,trace organics,medium stiff,mottled brown to brownish gray,moist. 1 pH=5.4,Sulfates= 5.29 mg/L,Chlorides= 5- - 0.585 mg/L Grades to medium plasticity,some weathered rock fragments,stiff,reddish TA 2 `brown,moist. - -560 - - _ j I 10- x . ,x.:.:. BASALT,completely to highly weathered,extremely to very weak,wet on fractures,highly fractured,reddish brown. xxx% _ _ `x.,, m o - xxx. _ o N tXXX C 4 _ H tXXX 0O . .x. xx X xGrades to highly to extremely weathered,very weak 45 ' XXX` Excavator notes stiff, 0. 15- xxx - - not refusal as TP-1 II: txxx xxx - - xxx O ra (xX XXX .x.0 - U) ii 'xxxxxx Grades to highly to moderately weathered,weak to very weak LL-550 - - 0 o XXX . . . • Test Pit terminated at a depth of 19.0'bgs on 6/4/2003 due to practical refusal. 1i 20- - - 1- 0 0 a c 0 a w URS 4 Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-07-2003 Project Number: 25695391.10001 Date(s) 6/4/2003 Logged JOSChecked BJD Excavated By By Length of 15.0 feet Width of 3.0 feet Depth of 15.0 feet Excavation Excavation Excavation Excavation Case 9030 B Trackhoe Excavation BEC Approximate —563.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface Grassy Field Condition a) c ca> C p ui o H J m N ii a) W Zu _o e'- °' 'm_ REMARKS AND > a.- a a.a s MATERIAL DESCRIPTION D-m 'a 'a E E E P-3 y. 8 o OTHER TESTS W 1... a w co to Z o o a)`o 2O o 0 jLEAN CLAY[CL],low plasticity, rapid dilatancy,micaceous,trace organics,medium stiff,mottled brown,moist. —560 Grades to brown to brownish yellow Grades to medium plasticity,slow dilatancy,some angular basaltic gravel, stiff,reddish brown. 10 — 0 - - N Q a-—550 - - N S 'I .'Xxxxx BASALT,highly weathered,very weak,highly fractured,5-10%vesicles .2mm dia., Fe,Cl,Mn filled fractures. o 15 .'x'x Test Pit terminated at a depth of 15.0'bgs on 6/4/2003 due to excavator kbreakdown. co0 0 •LL - - - 6 0 N O mi O. 20— — — I1- cc • O a -t 0 a Cr URS Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-08-2003 Project Number: 25695391.10001 Date(s) 6/4/2003 Logged JDS Checked BJD Excavated By By Length of Width of Depth of Excavation 15.0 feet Excavation 3.0 feet Excavation 15.0 feet Excavation Case 9030 B Trackhoe Excavation BEC Approximate Equipment Contractor Surface Elevation 569.0 feet MSL Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface GrassyField Condition CD a> c co0) Q 0 c >, o v+ o o a. > as - as a>m g SI-= a> REMARKS AND >.. Q.. i a_a s MATERIAL DESCRIPTION = = c OTHER TESTS > a>o E EE a N" a) LT,-.1) �»� as as = 0 o `o co cnZ 0 nU a 0 LEAN CLAY(CLI,low plasticity,rapid dilatancy,trace organics, miceaous,medium stiff,mottled brown to yellowish brown,moist. •5— — Grades to medium plasticity,slow dilatancy,fine angular basaltic gravel, 2 medium stiff,moist _ —560 - % - 10— — x BASALT,highly weathered,very weak,5-10%vesicles>2mm dia., •xxxxx reddish brown. M x x O x x xx- N `4,3Q - - ~ x Grades to highly to moderately weathered,weak,grayish brown,highly xxxxx fractured. o o ,xxxx N - - - m xxxx xx o 15 xxxx Test Pit terminated at a depth of 15.0'on 6/4/2003 due to difficult excavating conditions. I- I- - - J CO CO0 Q _ co r m LL -' - - O 0 . N *—550 - U E ,1 20— — — C 0 0_ c 8. Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-09-2003 Project Number: 25695391.10001 Date(s) 6/4/2003 Logged JDS Checked BJD Excavated By By Length of Width of Depth of Excavation 15.0 feet Excavation 3.0 feet Excavation 14.5 feet ExcavationCase 9030 B Trackhoe Excavation BEC Approximate .-564.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface GrassyField Condition CD c C T O co o' W W a> a� U a a'� REMARKS AND >}, n-.- a..n MATERIAL DESCRIPTION a� aa) 0 m E E E m �,2, 8 c OTHER TESTS w o- 0� co Z •0 0 I p 0 2 0 o- jLEAN CLAY[CL],low plasticity,rapid dilatancy,micaceous,mottled brown,moist. d 1 —560 - 5— — Increase in moisture content - Grades to medium plasticity,slow dilatancy,trace angular basaltic gravel. stiff,reddish brown,moist. 10 — 2 j 0 x x x BASALT, highly weathered,very weak,5-10%vesicles>2mm dia., 9 �xxx reddish brown. , x xxx U. - x x x - xxx x Increases to highly to moderately weathered,weak to moderately strong, o grayish brown. —550 cxxxxxx- xxxxxx Test Pit terminated at a depth of 14.5'bgs on 6/4/2003 due to difficult a. 15— —excavating conditions. — a J 0 �r F m LLL - _ - a 0 N 0 0 I FI 20— — — I- K 0 a _ a Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-10-2003 Project Number: 25695391.10001 Date(s) 6/4/2003Logged Checked Excavated By JDS By BJD Length of 15.0 feet Width of 3.0 feet Depth of Excavation Excavation Excavation 13.0 feet Excavation Excavation Case 9030 B Trackhoe Contractor BEC Approximate —562.0 feet MSL Equipment _Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface GrassyField Condition rn a p y O h-.) J c d > >� C:),.• 0. cLQ a MATERIAL DESCRIPTION REMARKS AND W ) �.(' E E @ •y fl)`O OTHER TESTS rn u)Z C7 0 �U a % LEAN CLAY[CL],low plasticity, rapid dilatancy,trace organics, micaceous,medium stiff,mottled brown,moist. —560 - 1 Grades to yellowish brown to brown 5- Grades to medium plasticity,slow dilatancy,trace gravel,stiff,reddish brown,moist. 10— BASALT,highly weathered,very weak,5-10%vesicles>2mm dia.,highly fractured,reddish brown,moist. —550 ; Grades to highly to moderately weathered,weak to moderately strong 0 xxx Test Pit terminated at a depth of 13.0'bgs on 6/4/2003 due to difficult n excavating conditions. O n a 15— — U' -J J U) m O O a7 U I 20— _ re 0 a URS Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-11-2003 Project Number: 25695391.10001 Date(s) 6/4/2003 Logged JDS Checked BJD Excavated By By Length of Width of Depth of 15.0 feet 3.0 16.5 feet Excavation Excavation feet Excavation Excavation Case 9030 B Trackhoe Excavation BEC Approximate —558.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface Gress Field Condition Y 0) C C T O co O 0 o co 4) m m a) a� 0 3 _ REMARKS AND >. 1-, a am s MATERIAL DESCRIPTION w E E E caa �, W o OTHER TESTS • w. o� Cl) inZ C7 0 0 LSU a % LEAN CLAY[CL],low plasticity,rapid dilatancy,trace organics,medium stiff,mottled brown,moist. 1 _ 5— % — j - Grades to medium plasticity,slow dilatancy,some angular basaltic gravel, stiff,mottled reddish brown,moist. —550 d 2 / - 10— % — xxxxxBASALT,highly weathered,very weak,5-10%vesicles>2mm dia.,highly XxxxX fractured,Fe,Cl,Mn filled fractures,reddish brown. C., _ x x 0 x x . xzxx : xxx d. - 'xxxxx - - I- x xx i] :xxxxxx 0 x X m x Grades to highly to moderately weathered,weak to moderately strong n a 15— `xxx %— — x xxx o n. xxxxxx m - XxxxXx Jx x x D x Test Pit terminated at a depth of 16.5'bgs on 6/4/2003 due to difficult excavating conditions. Li:—540 - - - 0 0,50 mI a. 1--1 20— — — F o o a t 0 a URS 1 Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-12-2003 Project Number: 25695391.10001 Date(s) 6/4/2003 Logged JDS Checked Excavated By By BJD Length of 15.0 feet Width of 3.0 feet Depth of 15.5 feet Excavation Excavation Excavation Excavation Case 9030 B Trackhoe Excavation BEC Approximate —562.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface Grass Field Condition y O) c c O a O 0 J o L N >.• 0..- a a� MATERIAL DESCRIPTION REMARKS AND - (I)i xu E E j �, o OTHER TESTS W taw xA xnZ ( �U xo i*k 0 LEAN CLAY[CL], low plasticity,rapid dilatancy,micaceous,trace j organics,medium stiff,mottled,moist. —560 - Grades to brown to brownish yellow 1 31.3 5— 2 Grades to medium plasticity,slow dilatancy,trace angular basaltic gravel, 33.1 pH=5.7,Sulfates= stiff,reddish brown,moist. 5.56 mg/L,Chlorides= 0.629 mg/L 10- 8 0 o—550 N x BASALT,highly weathered,very weak,5-10%vesicles<5mm dia., highly x fractured,Fe and Mn filled fractures,moist. d r o x mxxxxx x x Grades to highly to moderately weathered, weak to moderately strong 15— ` " x xx — — x? ` x a _ Test Pit terminated at a depth of 15.5'bgs on 6/4/2003 due to difficult J - excavating conditions. - J D m 0 N O O N C, U aI 20re 0 0 a c 0 re URS Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-13-2003 Project Number: 25695391.10001 Date(s) 6/4/2003 JDS Logged Checked BJD Excavated By By Length of Width of Depth of Excavation 15.0 feet Excavation 3.0 feet Excavation 15.0 feet Excavation Case 9030 B Trackhoe Excavation BEC Approximate Equipment Contractor Surface Elevation 551.0 feet MSL Water Groundwater Not Encountered Weather Sunny,80's Observations Location See Figure 2,Site Map Surface Grassy Field Condition C a) c a rn N c >. to 0 o w is - w w '45o REMARKS AND >.. Q..., a a_o MATERIAL DESCRIPTION ma) in u� o E E E c ; o OTHER TESTS m ay oo 04 �o cn cn z 0 2 U a 0 LEAN CLAYCL],low plasticity,rapid dilatancy,micaceous,trace organics,stiff,mottled brown,moist. —550 Grades to brown to brownish yellow 1 5— — Grades to medium plasticity,slow dilatancy,some angular basaltic gravels, stiff,reddish brown,moist. 10— / — —540 C., X�j o - XF/ .. BASALT,highly weathered,very weak,highly fractured,Fe,CI,Mn filled fractures,5-10%vesicles>2mm dia.,reddish brown. a - .X.%.X - m .".'.`. Grades to moderately weathered,weak to moderately strong 15 Test Pit terminated at a depth of 15.0'bgs on 6/4/2003 due to difficult excavating conditions. . J J 03 m O y LL - - ai U 20— °- 0—a—530 a Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-14-2003 Project Number: 25695391.10001 Date(s) 6/5/2003 Logged JDS Checked BJD Excavated By By Length of Width of Depth of Excavation 15.0 feet Excavation 3.0 feet Excavation 18.0 feet Excavation Case 9030 B Trackhoe Excavation BEC Approximate —554.0 feet MSL Equipment Contractor Surface Elevation Water Groundwater Not Encountered Weather Sunny,80's Observations Surface Location See Figure 2,Site MapCondition Grassy Field rn c o. o) 'w a a O , m0. N >4, n.r o. a.0 s MATERIAL DESCRIPTION . ' REMARKS AND a) w a) E E E a . °3 o OTHER TESTS w 0.- co 00 cn co z CD 2 o a 0 j LEAN CLAY[CL],low plasticity,rapid dilatancy,trace organics,medium stiff,brown,moist. Decrease in organics,mottled brown to yellowish brown - j —550 - % - 5 1 _ - j Grades to medium plasticity,no dilatancy,trace angular gravel,stiff 7 2 reddish brown,moist. - 10— — Degree of weathering decreases with depth,more gravel. a - N a - I- , o ""x"/x BASALT, highly weathered,very weak,highly fractured, <5 vesicles —540 - - >2mm dia., Fe,CI,Mn filled fractures,moist. - ."x 0. 15— '""""— — 0 " - "x""- Grades to highly to moderately weathered,weak m t"" " " "" 0 - - m t"""" " 'r. Test Pit terminated at a depth of 18.0'bgs on 6/5/2003 due to difficult gexcavating conditions. 0 U I 1 20— — o a. a. r 0 a Project: TTSD Alberta Rider Elementary School Log of Test Pit Project Location: Tigard, Oregon TP-15-2003 Project Number: 25695391.10001 Date(s) 6/5/2003 Bygged JDS Checked BJD Excavated Length of Width of By Excavation 15.0 feet Excavation 3.0 feet Depth of 13.0 feet Excavation Excavation Case 9030 B Trackhoe Excavation BEC Approximate Equipment Contractor Surface Elevation 554.0 feet MSL Water Groundwater Not Encountered Observations Weather Sunny,80's Location See Figure 2,Site Map Surface GrassyField Condition 0) 4) c > n 0 i- -i U 0 >.-. o... a a.o s MATERIAL DESCRIPTION �'c °' REMARKS AND Z w in rnEE 0 0 f'o OTHER TESTS 0 2 O Q. LEAN CLAY[CL],low plasticity,rapid dilatancy,trace organics, micaceous,medium stiff,some mottling,brown,moist. —540 1 Grades to brown to brownish yellow Grades to medium plasticity,no dilatancy,moist. 2 10— BASALT,highly weathered,very weak,highly fractured,Fe,Cl,Mn filled xxx fractures,reddish brown,moist. M _ N " x Grades to moderately to slightly weathered,moderately strong to strong Xxxxx d xxx Test Pit terminated at a depth of 12.0'bgs on 6/5/2003 due to difficult o excavating conditions. N—530 - - - 15— — — cD -J J CD CD 0 U) LL O O .6 0 20— 0 a C • 0 URS APPENDIX B Dynamic Cone Penetrometer Test Logs TIRS0:\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcpl 0 -1D -20 46- -3D P -40 -50 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 I - 5 254 - 10 381 - - 15 508 -{ - 20 635 -41- LEAN CLAY(CL)50.00' - 25 ' j I 762 -- 30 889 - + 35 1016 7 40 1143 j 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp2 0 - I -10 i .� -2C1 46- 17 -30 - 10 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - - 5 254 - - 10 381 - - 15 508 - - 20 635 LEAN CLAY(CL)50.00" - 25 762 - - 30 • 889 - - 35 1016 - - 40 1143 - - 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp3 0 -10 . , - -20_ -c 46- -- I I fli -30- o -40 -BO 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - - 5 254 - - 10 381 - - 15 508 - - 20 635 LEAN CLAY(CL)50.00" - 25 762 - - 30 889 - - 35 1016 - - 40 1143 - - 45 1270 50 _1 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp4 0 -10 � -20 -30 - - -50 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - - 5 254 - - 10 381 - - 15 508 - - 20 635 - LEAN CLAY(CL)50.00' - 25 762 - - 30 889 - - 35 1016 - - 40 1143- - 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp5 0 -'10 I - I ' -20_ L 15- -30 -40 -60 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - 5 254 - - 10 381 - T 15 I 508 - 20 635 LEAN CLAY(CL)50.00" - 25 762 - 30 889 - 35 1016 - 40 1143 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp6 0 - 1 -10 I _ I ' -2° -30 0 -40 -50 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - - 5 254 - - 10 381 - - 15 508 - - 20 635 -- LEAN CLAY(CL)50.00° — 25 762 - - 30 889 i - 35 1016 40 1143 - - 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp7 0 -�Ilf L-' - C - J - 0 I ' _ a -40 -60 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - - 5 254 - 10 381 - - 15 508 - t 20 635 - LEAN CLAY(CL)50.00" - 25 762 - -II 30 889 - t 35 1016 t t 40 1143 t li 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp8 0 -10 i -20 - -30 -40 -50 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 j - 5 254 1 - 10 381 - 15 508 j 20 635 - LEAN CLAY(CL)50.00° fi 25 762 - 30 889 + 35 1016 - 40 1143 1 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp9 0 I I -30 oI � -50 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - - 5 254 - - 10 381 - - 15 508 - - 20 635 - LEAN CLAY(CL)50.00° - 25 762 - - 30 889 - - 35 1016 _ - 40 1143 - - 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp10 0 _ -10 C -20 -30 I. O -40 -50- 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - 5 254 - 10 381 -._ 15 508 -- 20 635 LEAN CLAY(CL)50.00° -.- 25 762 30 889 35 1016 40 1143 45 1270 50 DCP TEST DATA Project: Tigard Tualatin School District Date: 6/27/03 Feature: parking Station: dcp11 • 0 ' -20 -30- fli - C - - .0 1 10 100 CBR (MM) TEST PROFILE (IN) 0 0 127 - 5 254 - - 10 381 - - 15 508 - - 20 635 LEAN CLAY(CL)50.00" - 25 762 - - 30 889 - - 35 1016 - - 40 1143 - - 45 1270 50 APPENDIX C Laboratory Testing 0:\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 80 70 CH or OH 60 o. X 50 W CI "A" LINE 40 co CL or OL -J -J 0- 30 m 20 • MH or OH 10 CL-ML ML or OL 0 0 10 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT,LL Sample Depth Sample Boring ID (feet) Symbol Moisture LL PL PI Classification B-02-2003 1 6-6.5 • 30.7 38 21 17 Lean Clay B-02-2003 2 11-11.5 m 27.0 47 23 25 Lean Clay 0 O N N N 9 CD fpn _ 8 0 C7 J 0 0 y F- a N H 0 J a 0 K W TTSD Alberta Rider Elementary School PLASTICITY CHART a Tigard, Oregon 25695391.10001 *�� V iW 80 70 CH or OH 60 X 50 W yi "A"LINE ~ 40 U Cl) CL or OL - 30 - m • 20 A MH or OH 10 - CL-ML ML or OL 0 - 0 10 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT,LL Sample Depth Sample Boring ID # (feet) Symbol Moisture LL PL PI Classification TP-02-2003 1 4-4.5 • 31.7 44 20 24 Lean Clay TP-02-2003 2 10-10.5 m 28.4 45 19 26 Lean Clay 0cn TP-05-2003 1 4-4.5 A 29.4 39 21 18 Lean Clay 0 N TP-05-2003 2 10-10.5 * 27.4 42 20 22 Lean Clay 9 a Ca 0 0 0. J J O m LL F a N ,.. 0 J a (7 TTSD Alberta Rider Elementary School PLASTICITY CHART a Tigard, Oregon 25695391.10001 • APPENDIX D Wetlands Review URS0:\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 Memorandum FM; To: Bryan Duevel,URS From: Noah Herlocker,URS Date: July 8,2003 Subject: Wetland Determination for the proposed Alberta Rider Elementary School Project Site On June 5,2003 a URS wetland scientist conducted an onsite wetland determination at the site of the proposed Alberta Rider Elementary School. The site is located in township 25, range 1 west, and section 9 near the intersection of SW 130th Street and SW Bull Mt.Road in Tigard, Oregon. This study examined all areas located within the property line for the future elementary school,excluding the current residence that will be granted to the Tigard/ Tualatin School District in the future. The unstudied property is identified on Figure 2 as "Future Expansion Area". This area was not examined at the request of the current residents. The determination consisted of a preliminary review of the National Wetland Inventory' (NWI)Beaverton Quadrangle(USFWS 1981) and the Washington County Soil Survey2 (USDA 1982). This review looked for mapped wetlands and/or the presence of hydric soils in the project vicinity. A subsequent pedestrian survey was conducted to look for potential wetland indicators identified in the 1987 Army Corps of Engineers Manual. The survey relied upon the presence or absence of hydrophytic vegetation,hydric soil characteristics, and primary and/or secondary hydrologic indicators to determine if wetlands were present on site. The site is located on a hillside associated with Bull Mountain. From the northern property line(SW Bull Mt.Rd.),the topography of the site includes an initial rise in elevation,heading south to a summit. After this,the topography slopes downward to the south becoming steeper toward the southern property line. The topography is steepest in the SE corner of the property(Figure 2). The north portion of the site,defined as the area rising from Bull Mt.Road to the highest point on site,is a grassland community dominated by tall oatgrass (Arrhenatherum eliatus, NI) and sweet vernalgrass(Anthoxanthum odoratum, FACU). The sub dominant vegetation consisted of Douglas fir(Pseudotsuga menziesii, NI) along the western property line;beaked hazelnut(Corylus cornuta, NI) along the northern property line; and a mix of herbaceous vegetation including: velvetgrass(Holcus lanatus, FAC), common vetch(Viccia sativa, NI), common dandelion(Taraxacum officianale, NI), oxeye daisy(Chrysanthemum leucanthemum, NL),Himalayan blackberry(Rubus discolor, FACU),English ivy(Hedera helix, NL), and Queen Anne's lace(Daucus carrota, NI). In the southern portion of the site, defined as the area of land sloping down gradient and south of the highest point on site,the vegetation was also dominated by tall oatgrass and ' U.S.Fish and Wildlife Service(USFWS). Beaverton Quadrangle,OR[map]. 1:24,000. 15 Minute Series. Portland,OR: USFWS,Region 1, 1981 2 Green, George L. 1982. Soil Survey of Washington County,Oregon. U.S.Department of Agriculture,Soil Conservation Service in cooperation with the Oregon Agricultural Experiment Station Page 1 of 2 URS sweet vernal grass. The sub dominant vegetation,however,included a different assemblage of plant species. These included Kentucky bluegrass(Poa pratensis, FAC), sheep sorrel (Rumex acetosella, FACU+),tall fescue(Festuca arundinaceae, FAC-),orchard grass (Dactylis glomerata, FACU),and English plantain(Plantago lanceolata, FAC). The preliminary review of the NWI map showed no wetlands in the vicinity of the project site. The soil survey mapped"Cornelious and Kinton silt loams,2 to 7 percent slopes" onsite. This soil series is not hydric. No evidence of prolonged seasonal or permanent surface inundation or soil saturation was observed. The topography of the site was steep enough to prevent surface water from collecting in quantities necessary for the formation of wetland characteristics.No hydrophitic vegetation was observed during the site visit. The three species with a wetland facultative status (FAC) are highly cosmopolitan species that inhabit a variety of soil types and moisture regimes. No wetland obligate status plant species were observed.Where the topography appeared its flattest, soil pits were excavated. Soils were examined in all four corners and the middle of the project site. Observed soils lacked hydric soil indicators. No primary or secondary indicators of hydrology were observed. Based on these observations,it was determined that no wetlands were present on the site of the proposed Alberta Rider Elementary School. Page 2 of 2