2-River Well 1 Geotechnical Memo Update - November 2024.pdf

TWG24L078 Page 1 of 11 November 19, 2024

62915 NE 18th Street, Suite 1, Bend, OR 97701 p | 541.382.4707 f | 541.383.8118 wallacegroup-inc.com

November 19, 2024

City of Bend c/o Mr. Nick McAteer 745 NW Bond Street Bend, Oregon 97701

Subject: Geotechnical Exploration Summary - Update

City River Well No. 1 341 SW Shevlin Hixon Drive Bend, Oregon

Project No. 24156-1

Dear Mr. McAteer:

The Wallace Group completed a supplemental geotechnical exploration to evaluate the subsurface conditions adjacent to the City River Well No. 1 (River Well), located east of SW

Shevlin Hixon Drive in Bend, Oregon. A Vicinity Map is shown in Figure 1. We understand that the City of Bend (Client) has observed signs of foundation distress of the pump house building, which appears to have progressed in the past several years. Based on information provided by

DOWL (project civil & structural engineer), the River Well building was constructed in approximately 1972. Previously, the Wallace Group completed an initial site investigation, floor level survey, and geotechnical engineering analyses and issued a geotechnical memorandum, dated June 9, 2023.

Based on the results of the previous floor level survey and evaluation of the settlement contours, subsurface explorations, laboratory testing, and engineering analyses, Wallace Group concluded that two potential causes of settlement of the well house include organic decomposition of the upper 1.5- to 4.5-foot-thick fill layer and consolidation of the very soft underlying decomposed tuff. Significant settlement of the River Well building is expected to occur during the lifetime of the structure. Wallace Group concluded that, in order the mitigate settlement of the well house, deep foundation elements will be needed which extend into the

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62915 NE 18th Street, Suite 1, Bend, OR 97701 p | 541.382.4707 f | 541.383.8118 wallacegroup-inc.com competent material below the very soft tuff (greater than 45- to 50-feet bgs). The borings drilled in 2023 were terminated at depths of approximately 41- to 50-feet bgs.

We understand that DOWL prepared a recommendations report which incorporated the initial geotechnical findings and issued a technical memorandum, dated September 12, 2023. Based on the initial findings and the proposed deep foundation remediation option strategy pursued by the Client, further exploration, including deeper subsurface data, was needed for design.

The purpose of this supplemental geotechnical exploration and analysis was to collect additional subsurface information and material properties for end-bearing deep foundations, which were proposed to mitigate future anticipated settlement of the River Well building. As part of this supplemental exploration, one (1) supplemental boring was drilled which extended to a depth of approximately 76-feet bgs.

Wallace Group used the results of the previous exploration and the supplemental boring to develop recommendations for remediation options contained herein. Based on our most recent conversations with the Client, we do not anticipate that exhaustive remediation options will be pursued to alleviate settlement of the River Well building. Rather, we anticipate that the Client may seek alternative well site(s) and transfer water rights to the new facility. The Client will monitor and maintain the existing River Well building during the transition phase to a new well house. Proposed maintenance by the Client will include cutting the existing slab-on-grade to provide relief to the well casing and other penetrations, installing flexible connections on existing utilities that radiate from the well house building, and establishing a monitoring program to be operated by the Client’s staff.

SUBSURFACE EXPLORATION

Subsurface conditions at the site were explored by drilling one (1) supplemental boring

(designated B-03) adjacent to the well building and previous boring B-02. The supplemental boring was drilled on August 29 and 30, 2024 and was advanced to a depth of approximately

76-feet bgs using mud-rotary drilling techniques. The geotechnical borings were drilled by

Western States Soil Conservation Inc., of Hubbard, Oregon. Approximate boring locations are shown on Figure 2, Exploration Location Map.

Wallace Group geotechnical professionals observed the drilling, standard penetration tests

(SPTs), collected samples, and visually classified the materials encountered. The boring logs in

Appendix A describe the materials encountered at each location explored. The soil types

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62915 NE 18th Street, Suite 1, Bend, OR 97701 p | 541.382.4707 f | 541.383.8118 wallacegroup-inc.com between explorations are anticipated to be similar; however, some variation should be expected. The stratigraphic contacts indicated at each exploration represent the approximate boundaries between soil and bedrock types.

A more complete description of the exploration methods, sampling techniques and depths, and soil classification terminology is presented in Appendix A, Field Exploration Summary.

LABORATORY TESTING

Soil samples were transported to our Bend geotechnical laboratory where they were visually-classified according to the Unified Soil Classification System (USCS). The classification is based on the ‘finer fraction’ of soil and gravel particles smaller than three-inches in diameter.

Representative samples were tested to evaluate soil engineering properties. The tests were completed in general accordance with the following standards:

• ASTM D2488 – Classification of Soil for Engineering Purposes,

• ASTM G57 – Resistivity,

• ASTM G51 – pH,

• ASTM D1140 – No. 200 Sieve Wash, and

• EPA 300 – Chloride & Sulfate.

The results of laboratory testing are presented in Appendix B.

SUBSURFACE CONDITIONS

Irrigated lawn surfaces were underlain by loose undocumented fill materials in all boring locations that contained high to very high organic content. The undocumented fill materials extended from the surface to depths ranging between approximately 1.5- to 6.5-feet below ground surface (bgs). Below the undocumented fill materials, alluvial deposits consisting of interbedded layers of sand, gravel, and silt were encountered. The alluvium extended to depths ranging between approximately 21- to 27.5-feet bgs and was generally medium dense to very dense. Very soft, saturated tuff deposits were encountered below the alluvium in all exploration locations. The saturated tuff was completely weathered and exhibited no welding or structure and instead consisted of free ash and pumice clasts. The weathered tuff extended to depths ranging between approximately 40.3- to 44-feet bgs and was underlain by dense gravel alluvium which ranged in thickness from less than 1-foot to at least 6.5-feet. Basalt bedrock was encountered in B-03 at a depth of approximately 41-feet bgs which extended the full depth of the boring of 76-feet.

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Landscaping and Undocumented Fill

Irrigated lawn surfaces were underlain by organic soil and undocumented fill materials in all exploration locations. The undocumented fill materials extended from the surface to depths ranging from approximately 1.5- to 6.5-feet bgs. The undocumented fill materials were composed of organic material, wood chips, and metal debris contained within a silt and sand soil. The undocumented fill material was generally very loose to medium dense, blackish brown with orange to gray mottling, and was fine to coarse grained. Where tested, organic content of the fill ranged from 4.7 to 21.1 percent by weight.

Alluvial Sand, Gravel, and Silt

Alluvium was encountered below the undocumented fill materials in all exploration locations.

The alluvium extended to depths ranging between approximately 21- to 27.5-feet bgs and was generally medium dense to very dense. The layer consisted of numerous interbedded layers of gravel, sand, and silt which reflect the variable depositional energy of the adjacent Deschutes

River. The material was fine to coarse grained, subangular to subrounded, moist to wet, and was blackish brown to tannish red and gray. Where tested, the organic content of the alluvial layer ranged from 1.0 to 1.2 percent.

Decomposed Tuff

Below the alluvium, saturated decomposed tuff was encountered that was very soft. This layer ranged in thickness from approximately 16.5- to 19.5-feet and extended to depths ranging from approximately 40.3- to 44-feet bgs. The material was completely weathered and exhibited very low strength based on the Standard Penetration Tests (SPT’s). Recovered samples had the appearance of fine ash with pumice clasts which became saturated below approximately 25-feet bgs. The material was tannish to orangish white, fine grained, and very moist to wet. A relatively undisturbed shelby tube sample was collected in B-01, and consolidation testing indicated the material is still consolidating; therefore, the layer is expected to settle even if no new loads are added.

Alluvial Gravel and Sand

Below the saturated tuff, very dense alluvial gravel, cobble, and sand were encountered which extended to depths of 41- to at least 50.4-feet bgs. Boring B-01 was terminated at a depth of

50.4 feet bgs, thus the thickness of the alluvium is unknown at this location. The material was medium dense to very dense, wet, subangular to rounded, and was fine to coarse grained.

Based on our explorations, this alluvial layer is thicker on the south side of the well house, where it is at least 6.5-feet thick.

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Basalt Bedrock

Basalt bedrock was encountered below alluvium in B-03 at a depth of 41-feet bgs. The basalt was gray, slightly weathered to unweathered, slightly fractured, flow banded and was vesicular to massive. The basalt exhibited very poor to fair rock quality. Based on results from other nearby projects, we anticipate the basalt has moderate (R3) to medium high strength (R4). We anticipate this basalt is associated with basalt of Newberry volcano.

Groundwater

In B-01, groundwater was measured at a depth of approximately 25.4-feet. Due to the mud-rotary drilling techniques used, groundwater depth was not easily discerned from B-02 and B-

03, but we anticipate it will be similar to B-01.

FLOOR LEVEL SURVEY

A floor level survey was performed by Wallace Group on May 9, 2023, using a water level manometer. Spot elevations of the interior floor slab were measured at building corners and areas where building distress was observed. Based on the results of the survey and evaluation of the contours, floor slab settlement has occurred throughout the well house building with the highest elevation adjacent to the well casing and the lowest elevation near the northwest corner. Between the well casing and the exterior edges of the building, approximately 1.1- to

3.5- inches of differential settlement was measured.

CONCLUSIONS AND DISCUSSION

Based on the results of the floor level survey, subsurface explorations, laboratory testing, and engineering analyses, two potential causes of settlement of the well house include organic decomposition of the upper 1.5- to 6.5-foot-thick fill layer and consolidation of the very soft decomposed tuff. We understand that the Client has requested geotechnical recommendations for deep foundation elements which could be installed to underpin the existing well house building. However, we also understand that the Client will seek to pursue other properties for an alternative well house location; this report could be utilized if those plans do not materialize.

If the Client would like to mitigate any potential settlement of the existing River Well building, we anticipate that micropiles can be installed, which will be socketed into the underlying basalt bedrock and underpin the well house building, mitigating future settlement.

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Estimated Future Settlement

The well house building has experienced a significant amount of settlement and additional settlement will occur as the organic material decays. Organic contents measured in the upper

1.5- to 6.5-feet ranged from 4.7 to 21.1 percent, and Wallace Group estimates that an additional 1- to 8- inches of settlement should be expected, dependent on the layer thickness, over the next 50-years.

The laboratory consolidation test results indicate that the decomposed tuff is still consolidating.

Even if no new loads are added, the site will continue to settle as a result of primary consolidation. Based on the decomposed tuff thickness and an overconsolidation ratio of 0.47, Wallace Group estimates that an additional 13- to 17-inches of consolidation settlement is expected over the next 50-years.

Estimates of total settlement caused by organic decay and consolidation settlement ranges between 14- to 25-inches within the footprint of the well house, where at least 3.5-inches of differential settlement has already occurred.

Micropile Underpinning

The high point observed on the slab adjacent to the well casing indicates that the well itself is not experiencing settlement while the surrounding ground surface, floor slab, and well house continue to settle. To mitigate additional future settlement of the River Well building, we recommend deep foundation elements are installed which gain end-bearing support in the basalt bedrock underlying the site. Based on the existing site conditions and subsurface materials, including a significant thickness of medium dense to dense gravel layer, we anticipate that micropiles will be an appropriate foundation type. We expect that Type A micropiles will be constructed with grout installed under gravity. The casing should remain in the weathered tuff zone since the very soft layer may potentially squeeze.

Micropiles should be designed to derive their axial capacity from end-bearing in basalt bedrock.

In order to mobilize the full end-bearing capacity, we anticipate micropiles will need to settle approximately 6-percent of the micropile diameter. We recommend that micropiles should be designed to be embedded at least 5-feet into competent basalt bedrock and be at least 51-feet deep. The final design embedment depth of micropiles is an iterative process and should be confirmed based on axial capacity, lateral capacity, and downdrag requirements. Micropiles end-bearing in competent basalt bedrock can be designed using a nominal (factored) tip resistance value of 100 kips per square foot (ksf), though we anticipate axial capacity for end-

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62915 NE 18th Street, Suite 1, Bend, OR 97701 p | 541.382.4707 f | 541.383.8118 wallacegroup-inc.com bearing in rock will be controlled by the structural capacity of the micropile. Nominal (factored) side friction in competent basalt bedrock is estimated at 3,800 pounds per square foot (psf).

Downdrag loads, as discussed below, should be accounted for in micropile design. For temporary uplift loads, including wind and/or seismic load, the axial resistance of the basalt bedrock is 4,800 psf. The resistance to uplift should be confirmed with the use of a tension load test to evaluate resistance to pullout and micropile structural strength. The settlement of properly constructed micropiles designed based on the recommendations should be less than

¾-inch for a 12-inch diameter micropile. The axial capacities provided are for isolated micropiles and micropiles in a group with a spacing of at least 30-inches or three (3) pile diameters, whichever is greater. The structural capacity of the micropiles should be confirmed by a structural engineer.

As the soil settles around the micropiles and the well casing, negative skin friction will be imposed on the elements in the layer above the dense gravel (encountered at depths ranging between 40.5- to 44-feet bgs). Therefore, we recommend that the structural capacity of the micropiles, well, and well casing are evaluated using negative skin friction values of 645 pounds per square foot (psf) in the upper sand and gravel (up to approximately 27.5-feet thick) and 820 psf in the decomposed tuff (up to approximately 20-feet thick).

Micropiles should be installed by a qualified contractor with demonstrated experience in this type of foundation and with similar subsurface conditions. We do expect potential for caving and / or squeezing during drilling installation within the soil zone and we anticipate that casing will be required. Concrete placement should start upon completion of the drilling and clean out.

The micropile holes should not be left open overnight. Concrete should be placed from the bottom up in a single operation using a tremie and/or a pumper pipe. The tremie pipe should be maintained at least 5 feet below the upper surface of the concrete during casting of the piers.

Corrosion Potential

Samples from the supplemental boring (B-03) were tested for corrosivity in anticipation of metallic and cementitious micropile installations. The recovered samples from the development area should be considered moderately corrosive based on the testing we performed. Based on soil resistivity readings between 6,170 to 9,744 Ohm-cm, the recovered samples were mildly corrosive. Chemical testing of pH indicates the soil has neutral alkalinity and has chloride and sulfate concentrations of less than 20 parts per million. Subgrade materials that have low resistivity and high concentrations of chloride and sulfate ions are considered corrosive.

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62915 NE 18th Street, Suite 1, Bend, OR 97701 p | 541.382.4707 f | 541.383.8118 wallacegroup-inc.com

Wallace Group is not a qualified corrosion expert, and we recommend proposed metallic installations, such as the micropiles, be designed by a qualified consultant. We also recommend that the consultant provide their input on what is the most appropriate concrete mix design for grout. Typically, Type V cement is used in areas where corrosive soil is present as it has higher resistance to sulfates. Corrosivity testing results are included in Appendix B.

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CLOSING

The services provided, as described in this summary letter, have been performed according to generally accepted engineering and design practices that exist in central Oregon at the time the work was performed. No warranty, express or implied, is provided.

We sincerely appreciate the opportunity to provide our professional services and trust this work meets the project design team requirements. If any questions arise concerning this letter, please contact our Bend office at (541) 382.4707.

Respectfully submitted, Wallace Group, Inc.

Lisa M. Splitter, P.E., G.E.

Senior Geotechnical Engineer

Adam Larson, P.E.

Project Geotechnical Engineer

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62915 NE 18th Street, Suite 1, Bend, OR 97701 p | 541.382.4707 f | 541.383.8118 wallacegroup-inc.com

ATTACHMENTS:

Figure 1: Vicinity Map

Figure 2: Exploration Location Map

Appendix A: Boring Logs

Appendix B: Laboratory Results

Appendix C: Photographs

REFERENCES:

AASHTO, 2020, LRFD Bridge Design Specifications (9th Edition), American Association of State Highway and Transportation Officials, Washington, D.C.

Guide to Drafting a Specification for Micropiles, Deep Foundation Institute, 1st Edition, 2004.

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This report has been authored and reviewed by the undersigned, respectively. This report is void if the original seal(s) and signature(s) are not included.

Adam Larson, P.E.

Project Geotechnical Engineer

Lisa M. Splitter, P.E., G.E.

Senior Geotechnical Engineer

FIGURES

APPENDIX A

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APPENDIX A

FIELD EXPLORATION SUMMARY

GENERAL

Subsurface conditions for the City of Bend Well #1 project, located in Bend, Oregon, were explored were explored by drilling three (3) borings (designated B-01 through B-03), at locations shown on Figure 2, Exploration Location Map. Geotechnical boring logs are included in this appendix. The exploration program was completed on April 24 to 25, 2023, and August

29 to 30, 2024. The procedures used to drill the borings and collect soil samples, and other field techniques are described in detail in this appendix. Unless otherwise noted, all soil sampling and classification procedures followed local engineering practices, which are in general conformance with relevant ASTM procedures and the Unified Soil Classification System (USCS).

“General conformance” means that certain local and common drilling and descriptive practices and methodologies have been followed.

BORINGS

Three (3) borings were drilled adjacent to the well house by Western States Soil Conservation, Inc. of Hubbard, Oregon. The borings were drilled to depths of approximately 41- to 76-feet below ground surface (bgs) with Central Mining Equipment (CME) track-mounted and truck-mounted drilling rigs. Borings were advanced using mud-rotary drilling and sampling techniques. Borings were abandoned in accordance with Oregon Water Resources Department requirements by backfilling the boreholes with bentonite.

MATERIAL DESCRIPTIONS

Soil samples were visually classified in the field as they were collected. Consistency, color, relative moisture, degree of plasticity, and other distinguishing characteristics of the samples were noted. Afterwards, the samples were re-examined in the laboratory, various standard classification tests were conducted, and the field classifications were modified where necessary. The terminology used in the soil classifications and rock descriptions are defined beginning on Page 3 and are included under material description on each log.

BORING LOGS

Figure A is a Legend explaining the information and symbols presented on the boring logs. The logs of the borings are presented on Figures A-1 through A-3. The logs describe the materials encountered and the depths where materials and/or characteristics of these materials changed, although the changes may be gradual. Where material types and descriptions changed between samples, the contacts were interpreted. On each boring log, the types of samples collected

(including their identification number) are reported, including laboratory test results, and

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Standard Penetration Test (SPT) blow counts. Corrected SPT blowcounts, presented on the boring logs, have been corrected for sampler type and hammer energy.

GROUNDWATER

Groundwater was measured in B-01 at a depth of 25.4-feet bgs during subsurface exploration for this project.

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TERMINOLOGY USED TO DESCRIBE SOIL AND ROCK

Soils exist in mixtures with varying proportions of components. The predominant soil, i.e., greater than 50 percent based upon total dry weight, is the primary soil type and is capitalized in our log descriptions, e.g., SAND, GRAVEL, SILT or CLAY. Lesser percentages of other constituents in the soil mixture are indicated by use of modifier words in general accordance with the Visual-Manual Procedure (ASTM D2488-93). “General Accordance” means that certain local and common descriptive practices have been followed. In accordance with ASTM D2488, group symbols (such as GP or CH) are applied on that portion of the soil passing the 3-inch

(75mm) sieve based upon visual examination. The following describes the use of soil names and modifying terms used to describe fine- and coarse-grained soils.

Fine - Grained SOILS (More than 50% fines passing 0.074 mm, #200 sieve) The primary soil type i.e. SILT or CLAY is designated through visual – manual procedures to evaluate soil toughness, dilatancy, dry strength, and plasticity. The following describes the terminology used to describe fine - grained soils and varies from ASTM 2488 terminology in the use of some common terms.

Primary soil NAME, adjective and symbols

Plasticity Description

Plasticity Index (PI)

SILT

ML & MH

CLAY

CL & CH

ORGANIC

SILT & CLAY

OL & OH

SILT Organic SILT Non-plastic 0 - 3

SILT Organic SILT Low plasticity 4 - 10

Clayey SILT Silty CLAY Organic clayey SILT Medium Plasticity

>10 – 20

Clayey SILT CLAY Organic silty CLAY High Plasticity >20 – 40

Clayey SILT CLAY Organic CLAY Very Plastic >40

Modifying terms describing secondary constituents, estimated to 5 percent increments, are applied as follows:

Description % Composition

Trace sand, trace gravel 5% - 10%

With sand; with gravel 15% - 25%

Sandy, or gravelly 30% - 45%

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Borderline Symbols, for example CH/MH, are used where soils are not distinctly in one category or where variable soil units contain more than one soil type. Dual Symbols, for example CL-ML, are used where two symbols are required in accordance with ASTM D2488.

Soil Consistency. Consistency terms are applied to fine-grained, plastic soils (i.e., PI > 4).

Descriptive terms are based on direct measure or correlation to the Standard Penetration Test N-value as determined by ASTM D1586-84, as follows.

Consistency Term SPT N-value Unconfined Compressive Strength Tons/sq.ft. kPa

Very soft Less than 2 Less than 0.25 Less than 24 Soft 2 - 4 0.25 - 0.5 24 - 48 Medium stiff 5 - 8 0.5 - 1.0 48 – 96 Stiff 9 - 15 1.0 - 2.0 96 – 192 Very stiff 16 - 30 2.0 - 4.0 192 – 383 Hard Over 30 Over 4.0 Over 383

Note: For SILT with low to non-plastic behavior, (i.e., PI < 4) a relative density description is applied.

Coarse-Grained Soils (less than 50% fines)

Coarse-grained soil descriptions, i.e., SAND or GRAVEL, are based on that portion of materials passing a 3-inch (75mm) sieve. Coarse-grained soil group symbols are applied in accordance with ASTM D2488 based upon the degree of grading, or distribution of grain sizes of the soil.

For example, well graded sand containing a wide range of grain sizes is designated SW; poorly graded gravel, GP, contains high percentages of only certain grain sizes. Terms applied to grain sizes follow.

Particle Diameter

Inches Millimeters

Sand (S) 0.003 - 0.19 0.075 - 4.8

Gravel (G) 0.19 - 3.0 4.8 - 75

Additional Constituents

Cobble 3.0 - 12 75 - 300

Boulder 12 - 120 300 - 3050

Rock Block >120 >3050

The primary soil type is capitalized, and the amount of ‘fines’ in the soil are described as indicated by the following examples. Other soil mixtures will provide similar descriptive names.

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Example: Coarse-Grained Soil Descriptions with Fines

5% fines

10% fines

(Dual Symbols) 15% to 45% fines

GRAVEL with trace silt: GW or GP GRAVEL with silt, GW-GM Silty GRAVEL: GM

SAND with trace clay: SW or SP SAND with clay, SP-SC Silty SAND: SM

Additional descriptive terminology applied to coarse-grained soils follow.

Coarse-Grained Soil Containing Secondary Constituents

Clean < 5% fines With sand or with gravel 15% - 25% sand or gravel Sandy or gravelly 30% - 45% sand or gravel With cobbles; with boulders Any amount cobbles or boulders.

Additional terms may be used to describe amount including abundant, scattered.

Cobble and boulder deposits may include a description of the matrix soils, as defined above.

Relative Density terms are applied to granular, non-plastic soils based on direct measure or correlation to the Standard Penetration Test N-value as determined by ASTM D1586.

Relative Density Term SPT N-value

Very loose 0 - 4

Loose 4 - 10

Medium dense 10 - 30

Dense 30 - 50

Very dense > 50

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Terminology Used to Describe Rock

Scale of Rock Strength

Description Designation

Unconfined Compressive Strength, psi

Unconfined Compressive Strength, MP

Field Identification

Very low strength R1 100 – 1000 0.7 – 7 Crumbles under firm blows with point of geology pick; can be peeled by a pocketknife.

Low strength R2 1,000 – 4,000 7 – 28 Can be peeled by a pocketknife with difficulty;

shallow indentation made by firm blows of geology pick.

Moderate strength R3 4,000 – 8,000 28 – 55 Cannot by scraped or peeled with a pocketknife; specimen can be fractured with a single firm blow of geology hammer.

Medium high strength

R4 8,000 – 16,000 55 – 110 Specimen requires more than one blow with a geology hammer to fracture it.

High strength R5 16,000 – 32,000 110 – 120 Specimen requires many blows of geology hammer to fracture it.

Very high strength

R6 > 32,000 > 220 Specimen can only be chipped with geology pick.

Descriptive Terminology for Joint Spacing or Bedding

Descriptive Term Spacing of Joints

Very close Less than 2 inches < 50 mm Close 2 inches - 1 foot 50 mm – 300 mm

Moderately close 1 foot - 3 feet 300 mm – 1 m Wide 3 feet -10 feet 1 m – 3 m

Very wide Greater than 10 feet > 3 m

Descriptive Terminology for Vesicularity

Descriptive Term Percent voids by volume

Dense < 1% Slightly vesicular 1 – 10%

Moderately vesicular 10 – 30% Highly vesicular 30 – 50%

Scoriaceous > 50%

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Correlation of RQD and Rock Quality

Rock Quality Descriptor RQD Value

Very poor 0 – 25 Poor 25 - 50 Fair 50 - 75

Good 75 - 90

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SCALE OF ROCK WEATHERING

Stage Description Quality Distinction

Fresh Rock is fresh, crystals are bright, a few joints may show slight staining because of ground water.

No Discoloration

Very Slight Rock is generally fresh, joints are stained, some joints may have thin clay coatings, crystals in broken faces show bright.

Discoloration only on major discontinuity surfaces i

Slight Rock is generally fresh, joints are stained, and discoloration extends into rock up to 1 in. Joints may contain clay. In granitoid rocks some feldspar crystals are dull and discolored. Rocks ring under hammer if crystalline.

Discoloration on all discontinuity surfaces and on rock

Moderate Significant portions of rock show discoloration and weathering effects. In granitoid rocks, most feldspars are dull and discolored; some are clayey. Rock has dull sound under hammer and shows significant loss of strength as compared with fresh rock.

Decomposition and/or disintegration < 50% of rock ii

Moderately Severe All rock, except quartz discolored or stained. In granitoid rocks, all feldspars dull and discolored and majority show kaolinization. Rock shows severe loss of strength and can be excavated with geologist’s pick.

Rock goes “clunk” when struck.

Decomposition and/or disintegration > 50%, but not complete

Severe All rock, except quartz, discolored or stained. Rock “fabric” is clear and evident but reduced in strength to strong soil. In granitoid rocks, all feldspars kaolinized to some extent. Some fragments of harder rock usually left, such as corestones in basalt.

Decomposition and/or disintegration > 75%, nearly complete

Very Severe All rock, except quartz, discolored or stained. Rock “fabric” is discernible, but mass effectively reduced to “soil” with only fragments of harder rock remaining.

Decomposition and/or disintegration 100% with structure/fabric intact

Complete Rock is reduced to “soil”. Rock “fabric” is not discernible, or only in small scattered locations. Quartz may be present as dikes or stringers.

Decomposition and/or disintegration 100% with structure/fabric destroyed

NOTES: i Discontinuities consist of any natural break (joint, fracture or fault) or plane of weakness (shear or gouge zone, bedding plane) in a rock mass ii Decomposition refers to chemical alteration of mineral grains; disintegration refers to mechanical breakdown iii Stage and description from ASCE Manual No. 56 (1976), quality distinction from Murray (1981)

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

ABBREVIATIONS

Rock Core (RC)

Standard Penetration Test

Shelby Tube

SAMPLER SYMBOLSLITHOLOGIC SYMBOLS

(Unified Soil Classification System)

WELL CONSTRUCTION SYMBOLS

KEY TO SYMBOLS

Water Level After 24 Hours, or as Shown

Water Level at End of Drilling, or as Shown

TV

PID

UCCS

ppm

BASALT: Basalt

FILL: Fill (artificial fill)

GM: USCS Silty Gravel

GP: USCS Poorly-graded Gravel

GP-GM: USCS Poorly-graded Gravel with Silt

ML: USCS Silt

SM: USCS Silty Sand

SP-SM: USCS Poorly-graded Sand with Silt

TOPSOIL: Topsoil

LL

PI

MC

DD

NP

FINES

PP

OC

LIQUID LIMIT (%)

PLASTIC INDEX (%)

MOISTURE CONTENT (%)

DRY DENSITY (PCF)

NON PLASTIC

PERCENT PASSING NO. 200 SIEVE

POCKET PENETROMETER (TSF)

ORGANIC CONTENT (%)

TORVANE

PHOTOIONIZATION DETECTOR

UNCONFINED COMPRESSION

PARTS PER MILLION

Water Level at Time of Drilling, or as Shown

K E

Y T

O S

Y M

B O

LS

W A

LL

A

C E

G R

O U

P D

A T

A T

E M

P

LA

T E

.G D

T

1/

1/

5:

W

:\G

IN

T P

R O

F

IL

E

S \B

E N

T

LE

Y \G

IN

T

\P R

O

JE

C T

S \2

-1 C

IT

Y

R

IV

E R

W E

LL

1.

G

P J

Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

Figure: A

SPT

S-1

SPT

S-2

SPT

S-3

SPT

S-4

SPT

S-5

SPT

S-6

SPT

S-7

SPT

S-8

SPT

S-9

SPT

S-10

SPT

S-11

SPT

S-12

SPT

S-13

OC: 2.1%

OC: 3.4%

OC: 1.0%

SM

SP-

SM

GP

ML

0.3

1.5

6.0

27.5

Green, grass sod SILTY SAND, gravel, moist, blackish brown with orangeish gray, fine to coarse grained, subangular to rounded, black organic lenses, [FILL] POORLY GRADED SAND WITH SILT AND GRAVEL, loose to medium dense, moist, blackish brown with whiteish red, fine to coarse grained, subangular to rounded, volcaniclastic grains

POORLY GRADED GRAVEL WITH SAND, medium dense to very dense, moist, brownish gray with whiteish red, fine to coarse grained, subangular to rounded, volcaniclastic grains

SILT WITH SAND, very soft, wet, orangeish yellow to brownish yellow, weathered tuffaceous pumice

NOTES

GROUND ELEVATION

LOGGED BY KAK

DRILLING METHOD CME 55

DRILLING CONTRACTOR Western States Soil Conservation Inc. GROUND WATER LEVELS:

CHECKED BY LMS

DATE STARTED 4/24/23 COMPLETED 4/24/23

AT TIME OF DRILLING 25.40 ft

24HRS AFTER DRILLING ---

S A

M P

LE

T

Y P

E N

U M

B E

R

D E

P T

H (f t)

BORING NUMBER B-01

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

T W

G -B

O R

IN

G

L O

G S

W

A

LL

A C

E G

R O

U P

D A

T A

T E

M P

LA

T

E .G

D T

1/

1/

5:

W :\G

IN

T

P R

O

F

IL

E S

\B E

N T

LE

Y

\G

IN

T \P

R O

JE

C

T S

\2

-1

C

IT

Y R

IV

E

R W

E

LL

.G P

J Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

B

LO

W C

O U

N T

S

C or re ct ed N

-V al ue

TESTS

U

.S .C

.S

G R

A P

H

IC

LO

G

MATERIAL DESCRIPTION

Figure: A - 1.1

S-14

SPT

S-15

ST

S-16

SPT

S-17

SPT

S-18

50/5"

60/5"

Consolidation Testing - See Appendix B

ML

GM

44.0

50.4

SILT WITH SAND, very soft, wet, orangeish yellow to brownish yellow, weathered tuffaceous pumice (continued)

SILTY GRAVEL WITH SAND, very dense, wet, grayish brown with brownish white, fine to coarse grained, subangular to rounded, volcaniclastic grains

Bottom of borehole at 50.4 feet.

S A

M P

LE

T

Y P

E N

U M

B E

R

D E

P T

H (f t)

BORING NUMBER B-01

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

T W

G -B

O R

IN

G

L O

G S

W

A

LL

A C

E G

R O

U P

D A

T A

T E

M P

LA

T

E .G

D T

1/

1/

5:

W :\G

IN

T

P R

O

F

IL

E S

\B E

N T

LE

Y

\G

IN

T \P

R O

JE

C

T S

\2

-1

C

IT

Y R

IV

E

R W

E

LL

.G P

J Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

B

LO

W C

O U

N T

S

C or re ct ed N

-V al ue

TESTS

U .S

.C .S

G R

A P

H

IC

LO

G

Figure: A - 1.2

SPT

S-2

SPT

S-3

SPT

S-4

SPT

S-5

SPT

S-6

SPT

S-7

SPT

S-8

SPT

S-9

SPT

S-10

OC: 4.7%

OC: 21.1%

OC: 1.2%

SM

SM

GP-

GM

GP

ML

GP-

GM

ML

0.3

4.5

6.0

9.0

16.0

17.5

21.0

Green, grass sod SILTY SAND, moist, brown, fine to coarse grained, subangular to subrounded, organic chips, metal shavings, [FILL]

SILTY SAND WITH GRAVEL, medium dense, moist, blackish brown with reddish gray, fine to coarse grained, subangular to rounded

POORLY GRADED GRAVEL WITH SILT AND SAND, very dense, moist, blackish brown with tannish red, fine to coarse grained, subangular to rounded, volcaniclastic grains

POORLY GRADED GRAVEL WITH SAND, medium dense, moist, blackish brown with red, fine to coarse grained, subangular to rounded, volcaniclastic grains

SILT WITH SAND, silt, moist, brown, fine grained

POORLY GRADED GRAVEL WITH SILT AND SAND, medium dense, moist, blackish brown with reddish gray, fine to coarse grained, subangular to rounded, volcaniclastic grains

SILT WITH SAND, very soft, very moist to wet, tannish white to orangeish white, fine grained, weathered tuffaceous pumice

NOTES

GROUND ELEVATION

LOGGED BY KAK

DRILLING METHOD CME 55

DRILLING CONTRACTOR Western States Soil Conservation Inc. GROUND WATER LEVELS:

CHECKED BY LMS

DATE STARTED 4/24/23 COMPLETED 4/25/23

AT TIME OF DRILLING ---

24HRS AFTER DRILLING ---

S A

M P

LE

T

Y P

E N

U M

B E

R

D E

P T

H (f t)

BORING NUMBER B-02

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

T W

G -B

O R

IN

G

L O

G S

W

A

LL

A C

E G

R O

U P

D A

T A

T E

M P

LA

T

E .G

D T

1/

1/

5:

W :\G

IN

T

P R

O

F

IL

E S

\B E

N T

LE

Y

\G

IN

T \P

R O

JE

C

T S

\2

-1

C

IT

Y R

IV

E

R W

E

LL

.G P

J Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

B

LO

W C

O U

N T

S

C or re ct ed N

-V al ue

TESTS

U

.S .C

.S

G R

A P

H

IC

LO

G

Figure: A - 2.1

S-11

SPT

S-12

50/3"

83/9"

ML

GP

40.5

41.3

SILT WITH SAND, very soft, very moist to wet, tannish white to orangeish white, fine grained, weathered tuffaceous pumice (continued)

POORLY GRADED GRAVEL WITH SAND, cobbles, very dense, wet, blackish gray, fine to coarse grained, subangular to rounded

Bottom of borehole at 41.3 feet.

S A

M P

LE

T

Y P

E N

U M

B E

R

D E

P T

H (f t)

BORING NUMBER B-02

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

T W

G -B

O R

IN

G

L O

G S

W

A

LL

A C

E G

R O

U P

D A

T A

T E

M P

LA

T

E .G

D T

1/

1/

5:

W :\G

IN

T

P R

O

F

IL

E S

\B E

N T

LE

Y

\G

IN

T \P

R O

JE

C

T S

\2

-1

C

IT

Y R

IV

E

R W

E

LL

.G P

J Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

B

LO

W C

O U

N T

S

C or re ct ed N

-V al ue

TESTS

U .S

.C .S

G R

A P

H

IC

LO

G

Figure: A - 2.2

SPT

S-2

SPT

S-3

SPT

S-4

SPT

S-5

SPT

S-6

ST

ST-1

Corrosion Testing

- See Appendix B

SM

GP

ML

0.3

6.5

22.0

Green, grass sod SILTY SAND, gravel, moist, blackish brown with orangeish gray, fine to coarse grained, subangular to rounded, black organic lenses, wood waste, organics, [FILL]

POORLY GRADED GRAVEL WITH SAND, medium dense to very dense, moist, brownish gray with whiteish red, fine to coarse grained, subangular to rounded, volcaniclastic grains

SILT WITH SAND, very soft, wet, orangeish yellow to brownish yellow, weathered tuffaceous pumice

NOTES

GROUND ELEVATION

LOGGED BY KAK

DRILLING METHOD CME 75

DRILLING CONTRACTOR Western States Soil Conservation Inc. GROUND WATER LEVELS:

CHECKED BY AML

DATE STARTED 8/29/24 COMPLETED 8/30/24

AT TIME OF DRILLING ---

24HRS AFTER DRILLING ---

S A

M P

LE

T

Y P

E N

U M

B E

R

D E

P T

H (f t)

BORING NUMBER B-03

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

T W

G -B

O R

IN

G

L O

G S

W

A

LL

A C

E G

R O

U P

D A

T A

T E

M P

LA

T

E .G

D T

1/

1/

5:

W :\G

IN

T

P R

O

F

IL

E S

\B E

N T

LE

Y

\G

IN

T \P

R O

JE

C

T S

\2

-1

C

IT

Y R

IV

E

R W

E

LL

.G P

J Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

R E

C O

V E

R Y

(R

Q D

B

LO

W C

O U

N T

S

C or re ct ed N

-V al ue

TESTS

U .S

.C .S

G R

A P

H

IC

LO

G

Figure: A - 3.1

S-7

SPT

S-8

ST

ST-2

SPT

S-9

SPT

S-10

SPT

S-11

RC

C-1

RC

C-2

RC

C-3

RC

C-4

RC

C-5

(0)

(70)

(11)

(46)

(50)

50/3"

50/2"

50/2"

80/9"

Corrosion Testing

- See Appendix B

FC: 28.4%

Corrosion

Testing - See Appendix B

ML

SM

40.3

41.0

SILT WITH SAND, very soft, wet, orangeish yellow to brownish yellow, weathered tuffaceous pumice (continued)

SILTY SAND WITH GRAVEL, medium dense, wet, grayish brown with brownish white, fine to coarse grained, subangular to rounded, volcaniclastic grains BASALT, slightly weathered to unweathered, slightly fractured, flow banded, gray, moderate strength to medium high strength, vesicular to massive

S A

M P

LE

T

Y P

E N

U M

B E

R

D E

P T

H (f t)

BORING NUMBER B-03

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

T W

G -B

O R

IN

G

L O

G S

W

A

LL

A C

E G

R O

U P

D A

T A

T E

M P

LA

T

E .G

D T

1/

1/

5:

W :\G

IN

T

P R

O

F

IL

E S

\B E

N T

LE

Y

\G

IN

T \P

R O

JE

C

T S

\2

-1

C

IT

Y R

IV

E

R W

E

LL

.G P

J Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

R E

C O

V E

R Y

(R

Q D

B

LO

W C

O U

N T

S

C or re ct ed N

-V al ue

TESTS

U .S

.C .S

G R

A P

H

IC

LO

G

Figure: A - 3.2

RC

C-6

RC

C-7

(67)

(40)

76.0

BASALT, slightly weathered to unweathered, slightly fractured, flow banded, gray, moderate strength to medium high strength, vesicular to massive (continued)

Bottom of borehole at 76.0 feet.

S A

M P

LE

T

Y P

E N

U M

B E

R

D E

P T

H (f t)

BORING NUMBER B-03

CLIENT City of Bend

PROJECT NUMBER 24156-1

PROJECT NAME Bend River Well #1

PROJECT LOCATION Bend, OR

T W

G -B

O R

IN

G

L O

G S

W

A

LL

A C

E G

R O

U P

D A

T A

T E

M P

LA

T

E .G

D T

1/

1/

5:

W :\G

IN

T

P R

O

F

IL

E S

\B E

N T

LE

Y

\G

IN

T \P

R O

JE

C

T S

\2

-1

C

IT

Y R

IV

E

R W

E

LL

.G P

J Wallace Group Inc.

62915 NE 18th Street, Suite 1 Bend, OR 97701

R E

C O

V E

R Y

(R

Q D

B

LO

W C

O U

N T

S

C or re ct ed N

-V al ue

TESTS

U .S

.C .S

G R

A P

H

IC

LO

G

Figure: A - 3.3

APPENDIX B

4/24 - 4/25/23 23044 - 1

WGG0311

4/27/2023

B-01 B-01 B-01

1.5' 3' 6'

Sand w/ Silt and Gravel Sand w/ Silt and Gravel Gravel w/ Sand

5704.6 5134.2 6030.3

5701.0 5120.1 6025.5

5530.5 4715.3 5530.0

174.1 418.9 500.3

170.5 404.8 495.5

Percent Moisture 27.7% 29.4% 13.7%

97.9 96.6 99.0

2.1 3.4 1.0

B-02 B-02 B-02

0' 1.5' 7.5'

Silty Sand Silty Sand Gravel w/Silt and Sand

5907.7 4821.6 6244.8

5889.9 4799.2 6236.4

5530.6 4715.3 5530.2

377.1 106.3 714.6

359.3 83.9 706.2

Percent Moisture 26.2% 103.2% 11.6%

95.3 78.9 98.8

4.7 21.1 1.2

Wt Dish & Dry Soil

Wt Dish & Ash

Wt of Dish

Wt of Dry Soil

Wt of Ash

Percent Ash

Percent Organics

Percent Organics

Location

Depth

Percent Ash

ASTM D-2974

ORGANIC CONTENT BY IGNITION

Location

Depth

Description

Date Analyzed:

DOWL

City River Well #1

PJH

LMS

Remarks: Furnace Temp. Used: 540° C

Moisture Content by proportion of oven-dried mass

Note: Data and results shown above include ASTM Test Method D-2974. This report pertains only to the material testedand/or inspected and is not to be reproduced without prior authorization of Wallace Group. If part of a larger document, this report is not to be removed or reproduced separately. This report is the property of the Client and shall not be distributed to other parties without Client's permission.

Client:

Project Name:

Technician:

Reviewed By:

Date Sampled:

Project No.:

Lab No.:

Description

Wt Dish & Dry Soil

Wt Dish & Ash

Wt of Dish

Wt of Dry Soil

Wt of Ash

62915 NE 18th St, Ste 1

Bend, OR 97701

541.382.4707 www.wallacegroup-inc.com

Revised 03/08/23

BGL Job No.: Project No.: Run By: PJ

Client: Date: Checked By: PJ

Project:

Boring: B-03

Sample: S-9

Depth, ft.: 40

Soil Type:

Wt of Dish & Dry Soil, gm 765.4 Weight of Dish, gm 304.3 Weight of Dry Soil, gm 461.1 Wt. Ret. on #4 Sieve, gm 144.3 Wt. Ret. on #200 Sieve, gm 329.9

% Gravel 31.3

% Sand 40.3

% Silt & Clay 28.4

Brown Silty

SAND w/

Gravel

026-035 24156-1

The Wallace Group 9/12/2024

River Well #1

Remarks: As an added benefit to our clients, and whenever possible, the mass and percent gravel is included in this report in order to aid in proper soil classification. Any gravel is always included in the percent retained on the #200 sieve even if it is not weighed separately to determine the percentage.

Percent Passing the No. 200

ASTM D1140

BGL # Date: PJ

Client: Project:

Remarks:

Chloride pH Sulfide Moisture

As Rec. Min Sat. mg/kg mg/kg % Qualitative At Test

Dry Wt. Dry Wt. Dry Wt. EH (mv) At Test by Lead %

Boring Sample, No. Depth, ft. ASTM G57 Cal 643 ASTM G57 EPA 300.0 EPA 300.0 EPA 300.0 ASTM G51 ASTM G200 Temp °C Acetate Paper ASTM D2216

B-03 S-3 5 - - 9,744 <20 21 0.0021 7.5 - - - 26.0 Very Dark Brown SAND w/ Silt, trace Gravel

B-03 S-7 30 - - 8,032 <20 <20 <0.0002 7.3 - - - 101.5 Yellow Silty SAND

B-03 S-9 40 - - 6,170 <20 <20 <0.0002 6.9 - - - 26.0 Brown Silty SAND w/ Gravel

(Redox) Soil Visual Description

The Wallace Group River Well #1 Proj. No: 24156-1

Sample Location or ID Resistivity @ 15.5 °C (Ohm-cm) Sulfate ORP

PJ

Corrosivity Tests Report

026-035 9/13/2024 Tested By: Checked:

APPENDIX C

TWG24L078 Figure D-1 November 19, 2024

Existing site conditions during supplemental exploration. View looks east.

Drilled boring exploration performed with truck-mounted CME drilling rig.

TWG24L078 Figure D-2 November 19, 2024

Mud-rotary drilling techniques were used for the supplemental boring.

B-03 core run C-2 with recovered basalt bedrock from approximately 51- to 56-feet bgs.

TWG24L078 Figure D-3 November 19, 2024

Bottom of B-03 core run C-2. Note fair rock quality.

B-03 core run C-3 from approximately 56- to 59-feet bgs. Note poor rock quality.