06_CA FTBR Senator Wash(1)_Pavement_Design_Sealed.pdf

SUBMITTED TO:

Jacobs Engineering Group 717 17th Street Denver, Colorado 80202

BY:

Shannon & Wilson, Inc.

1321 Bannock St., Suite 200 Denver, CO 80204

(303) 825-3800 www.shannonwilson.com

PAVEMENT DESIGN REPORT

CA FTBR Senator Wash (1) Ferguson Road to Imperial Dam

IMPERIAL COUNTY, CALIFORNIA

July 2020

Shannon & Wilson No: 105144-001

「 05「 44〇〇〇「

CA FTBR Sena†o「 Wash (l) Ferguson Road †o Imperial Dam

Pavemen† Design Repo什

Subm冊ed To: Jacd〕S Engineering Group

717 17th Street

Denver, CoIorado 80202

A壮n‥ Bervyn Wilbrink, PE

Subjec†: PAVEMENT DESiGN REPORT, CA FTBR SENATOR WASH (l) FERGUSON

ROAD TO IMPERIAL DAM, lMPERIAL COUNTY, CAL肝ORNIA

This report presents血e results of our geotechnical s山dy and pavement design recommendations for血e improvements to Senator Wash Road and McKinley Road and

WaS PrePared by the undersigred. ShannOn & Wilson prepared this report and participated in this project as a subcousultant to Jacobs Engineering Group. Our scope of services was

SPeCified in Professional Services Agreement Number 148015472 dated May 26, 2020.

We appreciate the opportunity to be of service to you on址s project. If you have questions

COnCeming this report, Or We may be of further service, Please contact us.

Sincerely, SHANNON & WILSON

整圏

Gregory R・ Fischer, PhD

Pre si dent

MLW:DAA:GRF :SDD/daa

、二二二二一二 一二ゝぺ二

Stephen Diem, PE, GE, PG, CEG

Asso ciate

」ui、/ 2020

CA FTBR Senator Wash (1) Ferguson Road to Imperial Dam Pavement Design Report

105144-001 July 2020 ii

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CONTENTS

1 Introduction

2 Project and Site Description

3 Subsurface Explorations and Laboratory Testing

4 Regional Geology and Subsurface Conditions

5 Pavement Recommendations

5.1 Design Methodology

5.2 Traffic Loading

5.3 Subgrade Soils

5.4 Sulfates

5.5 Full Depth Reclamation

5.6 Recommended Pavement Section

6 Construction and Materials Specifications

6.1 Site Preparation

6.2 Earthwork

6.2.1 Proof Rolling and Subgrade Preparation

6.2.2 Fill Placement, Moisture Conditioning, and Compaction

6.3 Paving Materials

7 Closure

8 References

Exhibits Exhibit 6-1: Recommended Materials for Pavements

Figures Figure 1: Vicinity Map Figure 2: Site and Exploration Plan

Appendices

Appendix A: Subsurface Explorations Appendix B: Laboratory Test Results Appendix C: Pavement Design Calculations Important Information

105144-001 July 2020

1 INTRODUCTION

This report summarizes the results of our subsurface exploration and laboratory testing program and presents pavement design recommendations and construction considerations for the proposed CA FT Senator Wash (1) Ferguson Road to Imperial Dam project (the Project) in Imperial County, California. Our services were completed in general accordance with our Task Order Agreement No. 148015472 with Jacobs Engineering Group (Jacobs) dated May 26, 2020. Our conclusions and recommendations in this report are based on:

The limitations of our approved scope, schedule, and budget described in our contract;

Our understanding of the Project and information provided by Jacobs;

Subsurface conditions observed in the borings at the time our explorations were completed; and

The results of testing performed on samples collected from the explorations.

The objective of our geotechnical study was to provide recommendations and construction considerations, as presented herein, for the proposed roadway reconstruction. The authorized scope of services was based on this objective and this report should not be used for other purposes without Shannon & Wilson’s review. If a service is not specifically indicated in this report, do not assume that it was performed.

2 PROJECT AND SITE DESCRIPTION

The Project is located in Imperial County, California (see Figure 1). Senator Wash Road and McKinley Road provide access to the Bureau of Land Management's (BLM) Hidden Shores, Imperial Dam, and Senator Wash Recreation areas. The roads also allow access to recreation facilities managed by BLM and Imperial Irrigation District. The project includes pavement improvements to (a) approximately 1.3 miles of Senator Wash Road extending from the intersection of Imperial Dam Road to the intersection of McKinley Road and

(b) approximately 1.2 miles of McKinley Road from the intersection of Senator Wash Road to the entrance of the Phil Swing Park parking area. Senator Wash Road and McKinley Road both consist of a two-lane roadway (one lane in each direction) paved with asphalt.

We understand that for both roadways, the existing pavement will be pulverized in place (full depth reclamation [FDR]) and regraded, and the roads will be resurfaced with asphalt pavement. We understand that the new roadway will not require widening or realignment.

We have provided an alternative design in this report if site grades cannot be raised.

105144-001 July 2020

3 SUBSURFACE EXPLORATIONS AND LABORATORY

TESTING

Shannon & Wilson conducted a field exploration program on June 1, 2020, to explore subsurface conditions along the proposed roadway alignment. The subsurface exploration program consisted of drilling and sampling three borings (designated SW-01 through SW-

03) along Senator Wash Road and three borings (designated SW-04 through SW-06) along McKinley Road, as shown in Figure 2. The borings were advanced to a typical depth of

5.5 feet below the ground surface.

Appendix A presents a discussion of the drilling and sampling procedures used to complete the borings and presents the individual exploration logs and an explanation of the symbols and terminology used. Additionally, photographs of the drilling locations are included in Appendix A.

Geotechnical laboratory tests were completed on selected samples retrieved from the borings to estimate index and engineering properties. Index tests included natural water content, grain size analysis, and Atterberg limits. Engineering properties tests included sulfate content and a Hveem Stabilometer (R-Value) test. Laboratory test results and a discussion of the testing procedures are included in Appendix B. The natural water content, fines content, and Atterberg limits are also shown on the individual boring logs included in Appendix A.

4 REGIONAL GEOLOGY AND SUBSURFACE

CONDITIONS

Based on our review of the Geologic map of the Laguna Dam 7.5-minute quadrangle, Arizona and California (Olmsted, 1972) and the Geologic map of California: San Diego-El Centro sheet (Strand, 1962), the surficial geology of the site consists of Pre-Cenozoic granitic and metamorphic rocks, Tertiary volcanic deposits, and Quaternary alluvial deposits.

The existing asphalt concrete pavement (ACP) ranged in thickness from 5 to 7 inches as measured in borings along Senator Wash Road, and 3 inches as measured in borings along McKinley Road. Below the pavement, the borings encountered (a) medium dense to very dense poorly graded sand with varying amounts of silt, clay and gravel (American Association of State Highway and Transportation Officials [AASHTO] soil classification A- 1-b), (b) loose to dense silty sand with varying amounts of gravel (AASHTO designation A- 2-4), and (c) medium stiff to stiff sandy lean clay (AASHTO designation A-6). In boring SW-

105144-001 July 2020

05, a very weak tuff was encountered at a depth of 4 feet. Untreated aggregate base course (UTBC) was not encountered below the asphalt in any of the borings.

Groundwater was encountered during drilling in boring SW-04 at a depth of 5.5 feet. While fluctuations of groundwater levels at the site are likely and will depend on many factors, including seasonal variations, local precipitation and flood events, groundwater is not anticipated to affect the design or construction of the Project.

Our observations are specific to the locations, depths, and dates noted on the exploration logs in Appendix A and may not be applicable to all areas of the site. There is no amount of exploration or laboratory testing that can precisely predict the characteristics, quality, or distribution of subsurface conditions at every location throughout the site. Variations in the subsurface conditions may occur between and below the borings. Also, the passage of time or intervening causes (natural and manmade) may result in changes to the conditions of the site and subsurface conditions.

5 PAVEMENT RECOMMENDATIONS

Performance of a pavement system depends on multiple factors including pavement material and thickness, subgrade strength, traffic loads and repetition, design life, and drainage characteristics. The following sections discuss these factors as they relate to the Project. For design of the Project, we completed pavement design for Senator Wash Road between the intersection with Imperial Dam Road to the intersection with McKinley Road, and along McKinley Road from the intersection with Senator Wash Road to the approach of the Phil Swing Park.

5.1 Design Methodology

Our pavement design and results are based on the design procedures presented in the 1993 AASHTO Guide for the Design of Pavement Structures with guidance from the U.S.

Department of Transportation (USDOT) and Federal Highway Administration (FHWA) Federal Lands Highway Project Development and Design Manual (PDDM), dated March 2008. Pavement design inputs and calculations are presented in Appendix C.

5.2 Traffic Loading

The traffic study consisted of average daily traffic (ADT) and assumptions for vehicle distribution provided by Jacobs, who provided 2020 and 2040 ADT values of 468 and 648 vehicles per day (vpd) for Senator Wash Road. For McKinley Road, Jacobs provided 2020 and 2040 ADT values of less than 400 and 560 vpd, respectively. Based on discussions

105144-001 July 2020 with Jacobs, we assumed the following vehicle distribution in our pavement analysis for both Senator Wash and McKinley Roads: 59.5% passenger cars, 20% pickup trucks or vans, 20% large recreational vehicles; and 0.5% buses and commercial trucks. For a 20-year design life, as indicated for a 3R project, and a 2% annually compounded growth rate, we estimated an 18-kip equivalent single axle loading (ESAL) of approximately 65,000 for Senator Wash Road, and 56,000 for McKinley Road. Our estimated ESAL calculations are provided in Appendix C.

5.3 Subgrade Soils

As discussed in the subsurface condition section, the explorations completed along the Senator Wash Road and McKinley Road generally consisted of sand with varying amounts of silt, clay, and gravel (AASHTO A-2-4 to A-1-b) and clay (AASHTO A-6). To estimate the strength of the subgrade material, an R-value test was completed on a bulk sample collected from boring SW-06 resulting in an R-Value of 71. Due to the variability in the subgrade across the Project, we assumed an R-Value of 50 for design. We used an AASHTO correlation between R-value and resilient modulus, which calculates a resilient modulus value of about 19,200 pounds per square inch.

5.4 Sulfates

The subgrade materials encountered at the project site can be corrosive to substructure elements. To assist in estimating the corrosion potential at the site, subgrade samples were tested for water soluble sulfates. The results are presented in Table B-1 in Appendix B.

The concentration of water-soluble sulfates measured in the samples was 0.099% to 0.530% by weight. Based on classifications as defined by ACI-318-19 (ACI, 2019), these test results suggest a moderate to severe degree of sulfate attack is possible on concrete exposed to site soils (exposure class S1 to S2).

The test results and the above discussion are provided to assist the designer in the selection of project materials, concrete type, or other features with respect to corrosion. As appropriate, the designer should consider protective measures, such as coatings, upsizing for section loss, or using alternative materials to reduce the corrosion potential.

5.5 Full Depth Reclamation

We understand that a pulverized FDR section is being considered for rehabilitation of the existing roadway pavement. The process involves pulverizing and mixing the existing asphalt with the underlying layers to create a uniformly blended, homogeneous material that will be incorporated into the proposed pavement section as a base course. The benefit

105144-001 July 2020 of the FDR process is that it allows the existing material to be recycled in place and eliminates the expense to export the material offsite. The requirements in the PDDM indicate a minimum R-value of 70 for the pulverized FDR. In our opinion, a blended material of pulverized asphalt and existing native soil will likely exceed this requirement.

5.6 Recommended Pavement Section

Using the PDDM procedures and the parameters outlined in Appendix C, we recommend the following pavement sections for Senator Wash Road and McKinley Road:

Senator Wash Road

3.0 inches of ACP overlying 8.0 inches of FDR

3.0 inches of ACP overlying 4.0 inches of UTBC

McKinley Road

3.0 inches of ACP overlying 4.0 inches of FDR

3.0 inches of ACP overlying 4.0 inches of UTBC

The above pavement sections reflect the observed ACP thicknesses in Senator Wash Road (5 to 7 inches) and McKinley Road (3 inches). In our opinion, the 4-inch FDR thickness represents the minimum thickness that can be implemented.

6 CONSTRUCTION AND MATERIALS SPECIFICATIONS

The applicability of the design parameters in Section 5 is contingent on good construction practice. Poor construction techniques may alter conditions from those upon which our recommendations are based, and therefore result in poor performance. Our analyses assumed that this project is constructed according to FP-14 U.S. Customary Units (USDOT and FHWA, 2014) construction standards. The following sections provide additional construction considerations for this project.

6.1 Site Preparation

We recommend that brush and other vegetation be cleared and roots and stumps be removed from all areas to be graded in accordance with FP-14 Sections 201 and 203. All surface and subsurface structures associated with current development of the site, including pavements (if FDR is not selected), utility poles, fence poles, underground utilities and other deleterious material, should also be removed. Any existing surficial topsoil and soil containing visible organics should be stripped and removed from all areas.

105144-001 July 2020

6.2 Earthwork

Earthwork, including placement of fill and subgrade preparation, should conform to the requirements provided in the FP-14 U.S. Customary Units (USDOT and FHWA, 2014) and the recommendations provided in the following sections.

6.2.1 Proof Rolling and Subgrade Preparation

In areas were FDR is not performed, the subgrade should be prepared in accordance with FP-14 Section 204.09.

6.2.2 Fill Placement, Moisture Conditioning, and Compaction

Granular fill should consist of onsite soils that are free of organics, contaminants, debris, rock fragments larger than 3 inches and should contain less than 20% fines. It should be noted that as the fines content of the soil increases (portion of soil particles passing a U.S.

Standard No. 200 sieve), soil becomes more sensitive to small changes in moisture content, and adequate compaction becomes more difficult to achieve. Import fill used within the roadway section should consist of Backfill Material (FP-14 Section 704.03) with a minimum R-value of 50.

All fill should be compacted to a dense/firm and unyielding condition in accordance with FP-14 Section 204.11. Fill materials should be moisture conditioned to within 2% of the optimum moisture content and compacted to at least 95% maximum density, as determined by AASHTO T180 as presented in FP-14 Section 204. Note that in boring SW-06, we observed elevated moisture contents that may require drying and could be moisture sensitive during earthwork operations.

6.3 Paving Materials

Exhibit 6-1 summarizes our recommendations for pavement materials. All specification sections reference FP-14 U.S. Customary Units, (USDOT and FHWA, 2014). We understand that the roadways will be constructed using ACP using a hot or warm mix asphalt in accordance with FP-14 Section 403. We understand that local practice for determining ACP mix designs is based on California Department of Transportation (CalTrans) job mix formula (JMF). As such, the roadway should be constructed in accordance with Section 39 of the CalTrans Standard Specifications for Asphalt Concrete (CalTrans, 2018).

105144-001 July 2020

Exhibit 6-1: Recommended Materials for Pavements

Material Specification Additional Requirements/Comments

UTBC FP-14 Section 302 Use Gradation C, D, or E

ACP FP-14 Section 403 Conform to current approved CalTrans JMF ACP gradation:

Either a single 3-inch lift of ¾” NMAS Type A hot mix asphalt, or two 1½-inch lifts of ½” NMAS Type A hot mix asphalt Binder:

Top Lift: PG 76-22, Lower Lift: PG 70-10 or PG 76-22

FDR FP-14 Section 303 Prepare existing road surface according to section 204.09

NOTES:

NMAS = Nominal Max Aggregate Size

The binder selection procedure is based on the anticipated pavement temperatures, traffic patterns, and local availability. The PDDM specifies the use of software developed by the FHWA Long Term Pavement Performance (LTPP) Bind (2019) to determine an appropriate binder for both high and low temperature ranges. The PDDM also specifies a reliability of 95% be achieved for binder performance. CalTrans Standard Specifications (2018) Section 92 includes specifications for furnishing asphalt binders.

Based on the output from the LTPP Bind software and the California Department of Transportation (CalTrans) Standard Specifications (2018), we recommend PG 76-22 binder for the upper lift and either PG 70-10 or PG 76-22 for the lower lift. A tack coat should be placed between subsequent lifts if the underlying lift will be used for traffic or left uncovered for a 24-hour period.

105144-001 July 2020

7 CLOSURE

This report has been prepared for the exclusive use of Jacobs and Central Federal Lands Highway Division for the purpose of providing pavement recommendations for the Senator Wash Roadway Improvements Project. This pavement design report should not be used without our approval if any of the following occurs:

Assumptions stated in this report have changed.

Project details change or new information becomes available such that our analyses and recommendations may be affected.

A substantial period of time has passed since the date of this report.

If any of these occur, we should be retained to review the applicability of our analyses and recommendations.

Within the limitations of scope, schedule and budget, the analyses, conclusions and recommendations presented in this report were prepared in accordance with generally accepted professional geotechnical and geological principles and practice in this area at the time this report was prepared. We make no other warranty, either express or implied.

Shannon & Wilson has prepared “Important Information about Your Geotechnical Report,” to assist you and others in understanding the use and limitations of our reports.

105144-001 July 2020

8 REFERENCES

American Association of State Highway and Transportation Officials (AASHTO), 1993, AASHTO guide for design of pavement structures: Washington, D.C., AASHTO, 2 v.

American Concrete Institute (ACI), 2019, Building code requirements for structural concrete and commentary, Farmington Hills, Mich., ACI 318-19.

California Department of Transportation (CalTrans), 2018, Standard Specifications.

Federal Highway Administration (FHWA), 2019, LTPP InfoPave: Tools: LTPPBind Online, available at: https://infopave.fhwa.dot.gov/Tools/LTPPBindOnline.

Olmsted, F.H., 1972, Geologic map of the Laguna Dam 7.5-minute quadrangle, Arizona and California: U.S. Geological Survey, Geologic Quadrangle Map GQ-1014, scale 1:24,000.

Strand, R.G., 1962, Geologic map of California: San Diego-El Centro sheet: California Division of Mines and Geology, Scale 1:250,000.

U.S. Department of Transportation (USDOT), Federal Highway Administration (FHWA), 2008, Federal Lands Highway project development and design manual (PDDM):

U.S. Department of Transportation and Federal Highway Administration.

Available from: http://flh.fhwa.dot.gov/resources/manuals/pddm/.

U.S. Department of Transportation (USDOT), Federal Highway Administration, 2014, Federal standard specifications for construction of roads and bridges on Federal Highway projects, FP-14 English Units: U.S. Department of Transportation and Federal Highway Administration, available from http://flh.fhwa.dot.gov/resources/pse/specs/.

https://infopave.fhwa.dot.gov/Tools/LTPPBindOnline http://flh.fhwa.dot.gov/resources/manuals/pddm/ http://flh.fhwa.dot.gov/resources/pse/specs/

She et 3

Sheet 3 Sheet 2

Sheet 2 Sheet 1

Sheet 1

Co lor ad o R ive r

0 7,000 14,000

Scale in Feet

CA FTBR Senator Wash (1) Imperial County, California

July 2020

VICINITY MAP

FIG. 1

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Sections of Alignment Shown on Designated Sheet Number of Figure 2

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Uta

Arizo

Nevada

California

San Francisco

Los Angeles

Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community, Sources: Esri, HERE, Garmin, FAO, NOAA, USGS, ©

OpenStreetMap contributors, and the GIS User Community

Project Location

Senator Wash Reservoir

Yuma

Bard

0 200 400

Scale in Feet

SITE AND EXPLORATION PLAN

FIG. 2

July 2020 105144-001

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Geotechnical and Environmental Consultants Sheet 1 of 3

Senator Wash Rd.

Im pe ria l D am R d.

M at ch L in e

(b el ow

S2

SW-01

Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

Senator Wash Rd.

Ferguson Rd.

M atch

Line (above)

Ma tch

Li ne

(s he et 2)

SW-02

Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

LEGEND

Boring Designation and Approximate Location

SW-01

CA FTBR Senator Wash (1) Imperial County, California

SITE AND EXPLORATION PLAN

FIG. 2

July 2020 105144-001

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Geotechnical and Environmental Consultants Sheet 2 of 3

Senator Wash Rd.

M atch Line (sheet 1)M at ch

L in e (b el ow

SW-03

Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

McKinley Rd.

Senator Wash Rd.

Matc h L ine (ab ove

M at ch L in e

(s he et

SW-04

Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

LEGEND

Boring Designation and Approximate Location

SITE AND EXPLORATION PLAN

FIG. 2

July 2020 105144-001

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Geotechnical and Environmental Consultants Sheet 3 of 3

McKinley Rd.Ma tch

Li ne

(s he et 2)

M at ch L in e

(b el ow

SW-05

Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

McKinley Rd.

S24

Matc h L ine (a bo ve)

SW-06

Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

LEGEND

Boring Designation and Approximate Location to Phil Swing Park

CA FT Senator Wash (1) Ferguson Road to Imperial Dam

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Appendix A: Subsurface Ex plorations

Appendix A

Subsurface Explorations

A.1 Introduction ........................................................................................................................... A-1

A.2 Explorations ........................................................................................................................... A-1

A.2.1 Soil Classification System........................................................................................ A-1

A.2.2 Standard Penetration Test (SPT) ............................................................................ A-1

A.2.3 Non-Standard Split Spoon Sampler ...................................................................... A-2

A.2.4 Bulk Sampling .......................................................................................................... A-2

Figures Figure A-1: Soil Description and Log Key Figure A-2: Rock Classification and Log Key Figure A-3 through A-8: Log of Boring SW-01 through SW-06 Figure A-9: Exploration Photographs

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A.1 INTRODUCTION

Shannon & Wilson’s field exploration program was conducted on June 1, 2020, and consisted of drilling six borings designated SW-01 through SW-06 at the locations shown on Figure 2. Photographs of boring locations are provided in Figure A-9. The methods used to conduct the field exploration program are described below.

A.2 EXPLORATIONS

The borings were coordinated (including subcontractor coordination and utility locates) and observed by Shannon & Wilson. Individual boring logs are presented in Figures A-3 through A-8. These exploration logs represent our interpretation of the contents of the field logs and select results of laboratory testing. Borings were completed by 2R Drilling, Inc.

(2R) of Chino, California (under subcontract to Shannon and Wilson) using a truck-mounted CME 75 drill rig. The borings were advanced to depths ranging from 5.5 to 7.0 feet below ground surface using 8-inch outside diameter hollow-stem-auger. On completion of drilling, the borings were backfilled with cuttings to the base of the existing asphalt and cold patch asphalt was used to restore the bore hole to the existing road surface elevation.

A.2.1 Soil Classification System

During drilling, our representative collected samples and prepared field logs of the explorations. Soil classification for this project was based on ASTM Designation: D2487, Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System), and ASTM Designation: D2488, Standard Practice for Description and Identification of Soils (Visual-Manual Procedure). The Unified Soil Classification System is summarized in Figure A-1.

The Shannon & Wilson representative classified rock samples in general accordance with the International Society for Rock Mechanics classification method. According to this system, rocks are classified based on the stratigraphic structure, rock strength, degree of weathering, and other properties. The rock classification system is summarized in Figure A- 2.

A.2.2 Standard Penetration Test (SPT)

Disturbed samples were obtained in the borings in general accordance with the Standard Penetration Test (SPT) (ASTM Designation: D1586). The SPT consists of driving a 2-inch outside diameter, 1.375-inch inside diameter split-spoon sampler a distance of 18 inches

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with a 140-pound hammer free-falling a distance of 30 inches. An automatic hammer system was used to advance the samplers. During sampling, the Shannon & Wilson field representative recorded the number of blows for each 6-inch increment of penetration and summed the blow counts for the last two 6-inch increments. This sum is recorded as the penetration resistance number, or N-value. If high penetration resistance prevented driving the entire 18 inches, the Shannon & Wilson field representative recorded the partial penetration depth and blow count. The N-values provide a means for evaluating the relative density or compactness of cohesionless (granular) soils and consistency or stiffness of cohesive (fine-grained) soils (see Figure A-1). The raw N-values are shown on the individual boring logs. Representative portions of the split-spoon sample obtained in conjunction with the SPT were placed in a screw-top plastic jar and transported to our laboratory.

A.2.3 Non-Standard Split Spoon Sampler

The non-standard split spoon sampler consisted of a 3.25-inch outside diameter sampler driven with the same methods and depths as the SPT sampler. The sampler barrel was lined with thin walled 2.5-inch-diameter stainless steel tubes. Samples gathered were classified by our field representative, sealed with plastic end caps and returned to our laboratory for further testing.

A.2.4 Bulk Sampling

Bulk soil samples were obtained by collecting drill cuttings from below the asphalt pavement in borings SW-01, SW-04, and SW-06. Approximately 20 to 30 pounds of cuttings were placed in a plastic bag and transported to our laboratory for further analysis and testing.

July 2020 105144-001

CA FT Senator Wash (1) Ferguson Road to Imperial Dam

Imperial County, California

1Gravel, sand, and fines estimated by mass. Other constituents, such as organics, cobbles, and boulders, estimated by volume.

2Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

A copy of the complete standard may be obtained from ASTM International, www.astm.org.

140 pounds with a 30-inch free fall.

Rope on 6- to 10-inch-diam. cathead 2-1/4 rope turns, > 100 rpm

NOTE: If automatic hammers are used, blow counts shown on boring logs should be adjusted to account for efficiency of hammer.

10 to 30 inches long Shoe I.D. = 1.375 inches Barrel I.D. = 1.5 inches Barrel O.D. = 2 inches

Sum blow counts for second and third 6-inch increments.

Refusal: 50 blows for 6 inches or less; 10 blows for 0 inches.

RELATIVE

CONSISTENCY

N, SPT,

BLOWS/FT.

5% to 12% fine-grained:

with Silt or with Clay 3

15% or more of a second coarse-grained constituent:

with Sand or with Gravel 5

< 5%

5 to 10%

15 to 25%

30 to 45%

50 to 100%

Surface Cement Seal

Asphalt or Cap

Slough

Inclinometer or Non-perforated Casing

Vibrating Wire Piezometer

N, SPT,

BLOWS/FT.

< 4 4 - 10

10 - 30 30 - 50

> 50

DESCRIPTION

< #200 (0.075 mm = 0.003 in.)

#200 to #40 (0.075 to 0.4 mm; 0.003 to 0.02 in.)

#40 to #10 (0.4 to 2 mm; 0.02 to 0.08 in.)

#10 to #4 (2 to 4.75 mm; 0.08 to 0.187 in.)

SIEVE NUMBER AND/OR APPROXIMATE SIZE

#4 to 3/4 in. (4.75 to 19 mm; 0.187 to 0.75 in.)

3/4 to 3 in. (19 to 76 mm)

3 to 12 in. (76 to 305 mm)

> 12 in. (305 mm)

Fine Coarse

Fine Medium Coarse

BOULDERS

COBBLES

GRAVEL

FINES

SAND

Sheet 1 of 3

CONSTITUENT2

SOIL DESCRIPTION

AND LOG KEY

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Absence of moisture, dusty, dry to the touch

Damp but no visible water

Visible free water, from below water table

FIG. A-1

Shannon & Wilson, Inc. (S&W), uses a soil identification system modified from the Unified Soil Classification System (USCS). Elements of the USCS and other definitions are provided on this and the following pages. Soil descriptions are based on visual-manual procedures (ASTM D2488) and laboratory testing procedures (ASTM D2487), if performed.

STANDARD PENETRATION TEST (SPT)

SPECIFICATIONS

Hammer:

Sampler:

N-Value:

Dry

Moist

Wet

MOISTURE CONTENT TERMS

Modifying (Secondary)

Precedes major constituent

Major

Minor Follows major constituent

1All percentages are by weight of total specimen passing a 3-inch sieve.

2The order of terms is: Modifying Major with Minor.

3Determined based on behavior.

4Determined based on which constituent comprises a larger percentage.

5Whichever is the lesser constituent.

COARSE-GRAINED

SOILS

(less than 50% fines)1

NOTE: Penetration resistances (N-values) shown on boring logs are as recorded in the field and have not been corrected for hammer efficiency, overburden, or other factors.

PARTICLE SIZE DEFINITIONS

RELATIVE DENSITY / CONSISTENCY

Sand or Gravel 4

30% or more coarse-grained:

Sandy or Gravelly 4

More than 12% fine-grained:

Silty or Clayey 3

15% to 30% coarse-grained:

with Sand or with Gravel 4

30% or more total coarse-grained and lesser coarse-grained constituent is 15% or more:

with Sand or with Gravel 5

Very soft Soft Medium stiff Stiff Very stiff Hard

Very loose Loose Medium dense Dense Very dense

RELATIVE

DENSITY

FINE-GRAINED SOILS

(50% or more fines)1

COHESIVE SOILS

< 2 2 - 4 4 - 8

8 - 15 15 - 30

> 30

COHESIONLESS SOILS

Silt, Lean Clay, Elastic Silt, or

Fat Clay 3

PERCENTAGES TERMS 1, 2

Trace

Few

Little

Some

Mostly

WELL AND BACKFILL SYMBOLS

Bentonite Cement Grout

Bentonite Grout

Bentonite Chips

Silica Sand

Perforated or Screened Casing

S&W INORGANIC SOIL CONSTITUENT DEFINITIONS

S O

IL

_C

LA

S

S _K

E Y

_P G

4_ C

F L

S E

N A

T O

R W

A S

H .G

P J

S H

A N

_W

IL

.G D

T

/7 /2

Ferguson Road to Imperial Dam

Imperial County, California

GC

SC

Inorganic

Organic

(more than 50% of coarse fraction retained on No. 4 sieve)

MAJOR DIVISIONS GROUP/GRAPHIC

SYMBOL

CH

OH

ML

CL

TYPICAL IDENTIFICATIONS

Gravel

Sand

Silty Sand; Silty Sand with Gravel

Clayey Sand; Clayey Sand with Gravel

Clayey Gravel; Clayey Gravel with Sand

Sheet 2 of 3

Gravels

Primarily organic matter, dark in color, and organic odor

SW

(more than 12% fines)

Silts and Clays

Silts and Clays

(more than 50% retained on No.

200 sieve)

(50% or more of coarse fraction passes the No. 4 sieve)

(liquid limit less than 50)

(liquid limit 50 or more)

Organic

Inorganic

FINE-GRAINED

SOILS

SM

Sands

Silty or Clayey Gravel

Silt; Silt with Sand or Gravel; Sandy or Gravelly Silt

Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or Gravelly Organic Silt or Clay

HIGHLY-

ORGANIC

SOILS

COARSE-

GRAINED

SOILS

OL

(less than 5% fines)

GW

Geotechnical and Environmental Consultants

SHANNON & WILSON, INC.

(less than 5% fines)

PT

FIG. A-1

(more than 12% fines)

MH

SP

GP

GM

Silty or Clayey Sand

Silty Gravel; Silty Gravel with Sand

(50% or more passes the No.

200 sieve)

SOIL DESCRIPTION

AND LOG KEY

Elastic Silt; Elastic Silt with Sand or Gravel; Sandy or Gravelly Elastic Silt

Fat Clay; Fat Clay with Sand or Gravel;

Sandy or Gravelly Fat Clay

Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or Gravelly Organic Silt or Clay

Poorly Graded Sand; Poorly Graded Sand with Gravel

Well-Graded Sand; Well-Graded Sand with Gravel

Well-Graded Gravel; Well-Graded Gravel with Sand

Poorly Graded Gravel; Poorly Graded Gravel with Sand

Lean Clay; Lean Clay with Sand or Gravel; Sandy or Gravelly Lean Clay

Peat or other highly organic soils (see

ASTM D4427)

NOTES

1. Dual symbols (symbols separated by a hyphen, i.e., SP-SM, Sand with Silt) are used for soils with between 5% and 12% fines or when the liquid limit and plasticity index values plot in the CL-ML area of the plasticity chart. Graphics shown on the logs for these soil types are a combination of the two graphic symbols (e.g., SP and SM).

2. Borderline symbols (symbols separated by a slash, i.e., CL/ML, Lean Clay to Silt; SP-SM/SM, Sand with Silt to Silty Sand) indicate that the soil properties are close to the defining boundary between two groups.

S O

IL

_C

LA

S

S _K

E Y

_P G

4_ C

F L

S E

N A

T O

R W

A S

H .G

P J

S H

A N

_W

IL

.G D

T

/7 /2

NOTE: No. 4 size = 4.75 mm = 0.187 in.; No. 200 size = 0.075 mm = 0.003 in.

UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)

(Modified From USACE Tech Memo 3-357, ASTM D2487, and ASTM D2488)

Ferguson Road to Imperial Dam

Imperial County, California

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

FIG. A-1

Sheet 3 of 3

SOIL DESCRIPTION

AND LOG KEY

1Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.

2Adapted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.

Interbedded

Laminated

Fissured

Slickensided

Blocky

Lensed

Homogeneous

ATD

Diam.

Elev.

ft.

FeO gal.

Horiz.

HSA

I.D.

in.

lbs.

MgO mm

MnO

NA

NP

O.D.

OW

pcf

PID

PMT

ppm psi

PVC

rpm

SPT

USCS

qu

VWP

Vert.

WOH

WOR

Wt.

Crumbles or breaks with handling or slight finger pressure.

Crumbles or breaks with considerable finger pressure.

Will not crumble or break with finger pressure.

PLASTICITY2

CEMENTATION TERMS1

GRADATION TERMS

STRUCTURE TERMS1

ACRONYMS AND ABBREVIATIONS

Alternating layers of varying material or color with layers at least 1/4-inch thick;

singular: bed.

Alternating layers of varying material or color with layers less than 1/4-inch thick;

singular: lamination.

Breaks along definite planes or fractures with little resistance.

Fracture planes appear polished or glossy; sometimes striated.

Cohesive soil that can be broken down into small angular lumps that resist further breakdown.

Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clay.

Same color and appearance throughout.

Narrow range of grain sizes present or, within the range of grain sizes present, one or more sizes are missing (Gap Graded). Meets criteria in ASTM D2487, if tested.

Full range and even distribution of grain sizes present. Meets criteria in ASTM D2487, if tested.

Poorly Graded

Well-Graded

Weak

Moderate

Strong

Irregular patches of different colors.

Soil disturbance or mixing by plants or animals.

Nonsorted sediment; sand and gravel in silt and/or clay matrix.

Material brought to surface by drilling.

Material that caved from sides of borehole.

Disturbed texture, mix of strengths.

VISUAL-MANUAL CRITERIA

A 1/8-in. thread cannot be rolled at any water content.

A thread can barely be rolled and a lump cannot be formed when drier than the plastic limit.

A thread is easy to roll and not much time is required to reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. A lump crumbles when drier than the plastic limit.

It takes considerable time rolling and kneading to reach the plastic limit. A thread can be rerolled several times after reaching the plastic limit. A lump can be formed without crumbling when drier than the plastic limit.

Sharp edges and unpolished planar surfaces.

Similar to angular, but with rounded edges.

Nearly planar sides with well-rounded edges.

Smoothly curved sides with no edges.

Width/thickness ratio > 3.

Length/width ratio > 3.

PARTICLE ANGULARITY AND SHAPE TERMS1

ADDITIONAL TERMS

Angular

Subangular

Subrounded

Rounded

Flat

Elongated

DESCRIPTION

Nonplastic

Low

Medium

High

At Time of Drilling Diameter Elevation Feet Iron Oxide Gallons Horizontal Hollow Stem Auger Inside Diameter Inches Pounds Magnesium Oxide Millimeter Manganese Oxide Not Applicable or Not Available Nonplastic Outside Diameter Observation Well Pounds per Cubic Foot Photo-Ionization Detector Pressuremeter Test Parts per Million Pounds per Square Inch Polyvinyl Chloride Rotations per Minute Standard Penetration Test Unified Soil Classification System Unconfined Compressive Strength Vibrating Wire Piezometer Vertical Weight of Hammer Weight of Rods Weight

Mottled

Bioturbated

Diamict

Cuttings

Slough

Sheared

APPROX.

PLASITICITY

INDEX

RANGE

< 4

4 to 10

10 to 20

> 20

S O

IL

_C

LA

S

S _K

E Y

_P G

4_ C

F L

S E

N A

T O

R W

A S

H .G

P J

S H

A N

_W

IL

.G D

T

/7 /2

Imperial County, California

105144-001July 2020

SHANNON & WILSON, INC.

ROCK CLASSIFICATION

AND LOG KEY

Sheet 1 of 2

JOINT (JT) - Planar break with little or no displacement

FRACTURE - Collective term for any natural break excluding shears, shear zones, and faults

FOLIATION JOINT (FJ) or BEDDING JOINT (BJ) - Joint along foliation or bedding

INCIPIENT JOINT (IJ) or INCIPIENT FRACTURE (IF) - Joint or fracture not evident until wetted and dried;

breaks along existing surface

RANDOM FRACTURE (RF) - Natural, very irregular fracture that does not belong to a set

BEDDING PLANE SEPARATION or PARTING - A separation along bedding after extraction from stress relief or slaking

FRACTURE ZONE (FZ) - Planar zone of broken rock without gouge

Extremely Close

Close

Moderate

Wide

Very Wide

Extremely Wide

2.5 to 8 in

6 to 20 ft

MECHANICAL BREAK (MB) - Breaks due to drilling or handling; drilling break (DB), hammer break (HB)

SHEAR (SH) - Surface of differential movement evident by presence of slickensides, striations, or polishing

SHEAR ZONE (SZ) - Zone of gouge and rock fragments bounded by planar shear surfaces

FAULT (FT) - Shear zone of significant extent;

differentiation from shear zone may be site-specific

DISCONTINUITY DATA

14 to 20

10 to 14

6 to 10

2 to 6

0 to 2

VERY ROUGH: Near vertical edges evident

ROUGH: Smooth ridges, surface abrasion

SLIGHTLY ROUGH: Asperities on surface can be felt

SMOOTH: Appears and feels smooth

SLICKENSIDED: Visible polishing, striated surface

JOINT ROUGHNESS COEFFICIENT (JRC)

DISCONTINUITY TERMS

Geotechnical and Environmental Consultants

FIG. A-2

Very Close

< 1 in

1 to 2.5 in

8 to 24 in

24 in to 6 ft

> 20 ft

36 to 145

>36,250

R0

Tight

Partly Open

145 to 700

700 to 3,600

Very Weak RockR1

R2

Very Tight

Open

Moderately Wide

Wide

Very Wide

Extremely Wide

Cavernous

<0.1mm

0.1 to 0.25mm

0.5 to 2.5mm

10mm to 1cm

1 to 10cm

10 to 100cm

>1m

0.25 to 0.5mm

2.5 to 10mm

Weak Rock

Fresh

Slight discoloration on surface

Rock reduced to a soil with relict rock texture

Extremely Strong Rock

No visible sign of rock material weathering

Residual Soil

Highly Weathered

Completely Weathered

Moderately Weathered

Slightly Weathered

Discoloring evident;

Less than half of the rock material is decomposed

WEATHERING

Entire rock mass discolored;

More than half of the rock material is decomposed

All rock material is converted to soil

R3

R4

R5

R6

STRENGTH

Medium Strong Rock

Strong Rock

Very Strong Rock 14,500 to 36,250

7,200 to 14,500

3,600 to 7,200

Extremely Weak Rock

R O

C K

C

LA

S S

K E

Y

P

(N E

W S

T R

E N

G T

H S

4_ C

F L

S E

N A

T O

R W

A S

H .G

P J

S H

A N

_W

IL

.G D

T

/7 /2

SPACING

SPACING

APERTURE WIDTH

DESCRIPTION

DESCRIPTION

DESCRIPTIONGRADE APPROX. UCS

(psi)

TERM SPACING

COEFFICIENT

DESCRIPTIONTERM

105144-001July 2020

Ferguson Road to Imperial Dam

Imperial County, California

GRAPHIC

SYMBOL

Conglomerate

Sandstone

Siltstone

Claystone

Shale

Breccia

Coal

Limestone

Dolomite

Coral

Gypsum

Halite

Calcite

Tuff

Rhyolite

Dacite

Andesite

Basalt

Granite

Grano-diorite

Diorite

Gabbro

Marble

Quartzite

Slate

Phyllite

Schist

Gneiss

Metamorphic Rocks

Intrusive Igneous Rocks

Extrusive Igneous Rocks

Evaporite Rocks

Carbonate Sedimentary

Rocks

Clastic Sedimentary

Rocks

BEDROCK TYPE ROCK NAME

Geotechnical and Environmental Consultants

FIG. A-2SHANNON & WILSON, INC.

ROCK CLASSIFICATION

AND LOG KEY

Sheet 2 of 2

R O

C K

C

LA

S S

K E

Y

P

C

F L

S E

N A

T O

R W

A S

H .G

P J

S H

A N

_W

IL

.G D

T

/7 /2

ROCK CLASSIFICATION SYMBOLS

S -1

B -1

S -2

S -3

5 inches of asphalt.

Dense to very dense, red-brown, Poorly Graded Sand with Silt and Gravel (SP-SM);

moist; trace to few cobbles. [A-1-b] Alluvium

BOTTOM OF BORING

COMPLETED ON 06/01/2020

G ro un dw at er n ot e nc ou nt er e d du ri ng d ri lli ng

0.4

5.5

July 2020

Sample Not Recovered

Hole Diam.:

Rod Type.:

Hammer Type:

SHANNON & WILSON, INC.

5.5 ft.

FIG. A-3

S am pl es

LOG OF BORING SW-01

8 in.

AWJ

Automatic

S ym bo l

Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual.

SOIL DESCRIPTION

NOTES

1. Refer to Figures A-1 and A-2 for explanation of symbols, codes, abbreviations, and definitions.

2. The discussion in the text of this report is necessary for a proper understanding of the nature of the subsurface materials.

3. Groundwater level, if indicated above, is for the date specified and may vary.

4. USCS designation is based on visual-manual classification and selected lab testing.

CA FT Senator Wash (1) Ferguson Road to Imperial Dam

Imperial County, California

0 60

Total Depth:

Top Elevation:

Vert. Datum:

Horiz. Datum:

20 40

Geotechnical and Environmental Consultants

105144-001

Hollow-Stem Auger 2R Drilling CME 75 Truck

LEGEND

Drilling Method:

Drilling Company:

Drill Rig Equipment:

Other Comments:

G ro un d

W at er

D ep th , f t.

Standard Penetration Test

Grab Sample

D ep th , f t.

Latitude:

Longitude:

Station:

Offset:

20 40

QCL 3

M A

S T

E R

_L O

G _E

_P O

C K

E T

P E

N _L

A T

LO

N G

4_

C F

L S

E N

A T

O R

W A

S H

.G P

J

/7 /2

Liquid Limit Natural Water Content

% Fines % Water Content

Plastic Limit

(<0.075mm)

(blows/foot)PENETRATION RESISTANCE Hammer Wt. & Drop: 140 lbs / 30 inches

NP

S -2

S -3

7 inches of asphalt.

Loose to medium dense, red-brown, Silty Sand (SM); moist; few gravel. [A-2-4] Alluvium

BOTTOM OF BORING

COMPLETED ON 06/01/2020

G ro un dw at er n ot e nc ou nt er e d du ri ng d ri lli ng

0.6

5.5

July 2020

Sample Not Recovered

Hole Diam.:

Rod Type.:

Hammer Type:

SHANNON & WILSON, INC.

5.5 ft.

FIG. A-4

S am pl es

LOG OF BORING SW-02

8 in.

AWJ

Automatic

S ym bo l

Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual.

SOIL DESCRIPTION

NOTES

1. Refer to Figures A-1 and A-2 for explanation of symbols, codes, abbreviations, and definitions.

2. The discussion in the text of this report is necessary for a proper understanding of the nature of the subsurface materials.

3. Groundwater level, if indicated above, is for the date specified and may vary.

4. USCS designation is based on visual-manual classification and selected lab testing.

CA FT Senator Wash (1) Ferguson Road to Imperial Dam

Imperial County, California

0 60

Total Depth:

Top Elevation:

Vert. Datum:

Horiz. Datum:

20 40

Geotechnical and Environmental Consultants

105144-001

Hollow-Stem Auger 2R Drilling CME 75 Truck

LEGEND

Drilling Method:

Drilling Company:

Drill Rig Equipment:

Other Comments:

G ro un d

W at er

D ep th , f t.

Standard Penetration Test

D ep th , f t.

Latitude:

Longitude:

Station:

Offset:

20 40

QCL 3

M A

S T

E R

_L O

G _E

_P O

C K

E T

P E

N _L

A T

LO

N G

4_

C F

L S

E N

A T

O R

W A

S H

.G P

J

/7 /2

Liquid Limit Natural Water Content

% Fines % Water Content

Plastic Limit

(<0.075mm)

(blows/foot)PENETRATION RESISTANCE

S

S

-3

6 inches of asphalt.

Medium dense to dense, brown, Silty Sand (SM); moist; few gravel. [A-2-4] Alluvium

BOTTOM OF BORING

COMPLETED ON 06/01/2020

* G ro un dw at er n ot e nc ou nt er e d du ri ng d ri lli ng

0.5

5.5

July 2020

Sample Not Recovered

Hole Diam.:

Rod Type.:

Hammer Type:

SHANNON & WILSON, INC.

5.5 ft.

FIG. A-5

S am pl es

LOG OF BORING SW-03

8 in.

AWJ

Automatic

S ym bo l

Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual.

SOIL DESCRIPTION

NOTES

1. Refer to Figures A-1 and A-2 for explanation of symbols, codes, abbreviations, and definitions.

2. The discussion in the text of this report is necessary for a proper understanding of the nature of the subsurface materials.

3. Groundwater level, if indicated above, is for the date specified and may vary.

4. USCS designation is based on visual-manual classification and selected lab testing.

CA FT Senator Wash (1) Ferguson Road to Imperial Dam

Imperial County, California

0 60

Total Depth:

Top Elevation:

Vert. Datum:

Horiz. Datum:

20 40

Geotechnical and Environmental Consultants

105144-001

Hollow-Stem Auger 2R Drilling CME 75 Truck

LEGEND

Drilling Method:

Drilling Company:

Drill Rig Equipment:

Other Comments:

G ro un d

W at er

D ep th , f t.

Standard Penetration Test

D ep th , f t.

Latitude:

Longitude:

Station:

Offset:

20 40

QCL 3

M A

S T

E R

_L O

G _E

_P O

C K

E T

P E

N _L

A T

LO

N G

4_

C F

L S

E N

A T

O R

W A

S H

.G P

J

/7 /2

Liquid Limit Natural Water Content

% Fines % Water Content

Plastic Limit

(<0.075mm)

(blows/foot)PENETRATION RESISTANCE

B -1

S -2

S -3

3 inches of asphalt.

Medium dense, brown, Poorly Graded Sand (SP); moist; few gravel and clay. [A-1-b] Alluvium

Medium stiff to stiff, red-brown, Sandy Lean Clay (CL); moist; few gravel. [A-6] Alluvium

Loose, brown to gray, Poorly Graded Sand (SP); moist. [A-1-b] Alluvium

BOTTOM OF BORING

COMPLETED ON 06/01/2020

D ur in g

D ril lin g

0.3

1.7

6.0

7.0

July 2020

Sample Not Recovered

Hole Diam.:

Rod Type.:

Hammer Type:

SHANNON & WILSON, INC.

7 ft.

FIG. A-6

S am pl es

LOG OF BORING SW-04

8 in.

AWJ

Automatic

S ym bo l

Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual.

SOIL DESCRIPTION

NOTES

1. Refer to Figures A-1 and A-2 for explanation of symbols, codes, abbreviations, and definitions.

2. The discussion in the text of this report is necessary for a proper understanding of the nature of the subsurface materials.

3. Groundwater level, if indicated above, is for the date specified and may vary.

4. USCS designation is based on visual-manual classification and selected lab testing.

CA FT Senator Wash (1) Ferguson Road to Imperial Dam

Imperial County, California

0 60

Total Depth:

Top Elevation:

Vert. Datum:

Horiz. Datum:

Ground Water Level ATD

20 40

Geotechnical and Environmental Consultants

105144-001

Hollow-Stem Auger 2R Drilling CME 75 Truck

LEGEND

Drilling Method:

Drilling Company:

Drill Rig Equipment:

Other Comments:

G ro un d

W at er

D ep th , f t.

Standard Penetration Test

Grab Sample

3.25" O.D. Split Spoon Sample

D ep th , f t.

Latitude:

Longitude:

Station:

Offset:

20 40

QCL 3

M A

S T

E R

_L O

G _E

_P O

C K

E T

P E

N _L

A T

LO

N G

4_

C F

L S

E N

A T

O R

W A

S H

.G P

J

/7 /2

Liquid Limit Natural Water Content

% Fines % Water Content

Plastic Limit

(<0.075mm)

(blows/foot)PENETRATION RESISTANCE

S -2

S -3

3 inches of asphalt.

Medium dense, gray to red-brown, Silty Sand with Gravel (SM); moist. [A-2-4] Fill

TUFF: very weak, light gray; highly to moderately weathered; contains clasts of rhyolite and andesite up to 1 inch in diameter.

BOTTOM OF BORING

COMPLETED ON 06/01/2020

G ro un dw at er n ot e nc ou nt er e d du ri ng d ri lli ng

0.3

4.0

5.5

July 2020

Sample Not Recovered

Hole Diam.:

Rod Type.:

Hammer Type:

SHANNON & WILSON, INC.

5.5 ft.

FIG. A-7

S am pl es

LOG OF BORING SW-05

8 in.

AWJ

Automatic

S ym bo l

Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual.

SOIL DESCRIPTION

NOTES

1. Refer to Figures A-1 and A-2 for explanation of symbols, codes, abbreviations, and definitions.

2. The discussion in the text of this report is necessary for a proper understanding of the nature of the subsurface materials.

3. Groundwater level, if indicated above, is for the date specified and may vary.

4. USCS designation is based on visual-manual classification and selected lab testing.

CA FT Senator Wash (1) Ferguson Road to Imperial Dam

Imperial County, California

0 60

Total Depth:

Top Elevation:

Vert. Datum:

Horiz. Datum:

20 40

Geotechnical and Environmental Consultants

105144-001

Hollow-Stem Auger 2R Drilling CME 75 Truck

LEGEND

Drilling Method:

Drilling Company:

Drill Rig Equipment:

Other Comments:

G ro un d

W at er

D ep th , f t.

Standard Penetration Test

D ep th , f t.

Latitude:

Longitude:

Station:

Offset:

20 40

QCL 3

M A

S T

E R

_L O

G _E

_P O

C K

E…