B08_22R0022_At7_P2_Specs.pdf

U.S. BUREAU OF LAND MANAGEMENT

LA POSA TYSON WASH LTVA

WASTEWATER LAGOON

QUARTZSITE, ARIZONA

U.S. BLM YUMA FIELD OFFICE

Yuma, Arizona

Construction Documents Phase 2

Project Specifications

U.S. DEPARTMENT OF THE INTERIOR

BUREAU OF LAND MANAGEMENT

June 2021 https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjRj7qiodjPAhXJWT4KHYVGDwYQjRwIBw&url=https://en.wikipedia.org/wiki/United_States_Department_of_the_Interior&bvm=bv.135475266,d.cWw&psig=AFQjCNE6hwjlcWlUZf-LlmIR9a_KRGs4CQ&ust=1476464552848630 https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjT2oXhoNjPAhVFVD4KHbUhAc4QjRwIBw&url=https://reports.blm.gov/reports.cfm?application%3DRAS&psig=AFQjCNGX6gpX3AX_gs4hjn1ylozu8zkjlw&ust=1476464381007529

TABLE OF CONTENTS 000000 - 1

TABLE OF CONTENTS

LA POSA TYSON WASH LTVA WASTEWATER LAGOON – PHASE 2

SPECIFICATIONS

DIVISION SECTION TITLE

DIVISION 01 – GENERAL REQUIREMENTS

000110 CERTIFICATIONS

003132 GEOTECHNICAL DATA

011000 SUMMARY

012500 SUBSTITUTION PROCEDURES

013100 PROJECT MANAGEMENT AND COORDINATION

013200 CONSTRUCTION PROGRESS DOCUMENTATION

013233 PHOTOGRAPHIC DOCUMENTATION

013300 SUBMITTAL PROCEDURES

014000 QUALITY REQUIREMENTS

014200 REFERENCES

015000 TEMPORARY FACILITIES AND CONTROLS

017300 EXECUTION

017329 CUTTING AND PATCHING

017419 CONSTRUCTION WASTE MANAGEMENT AND DISPOSAL

017700 CLOSEOUT PROCEDURES

017823 OPERATION AND MAINTENANCE DATA

017839 PROJECT RECORD DOCUMENTS

DIVISION 03 – CONCRETE

031100 CONCRETE FORMING

032000 CONCRETE REINFORCING

033000 CAST-IN-PLACE CONCRETE

DIVISION 31 – EARTHWORK

311000 SITE CLEARING

312000 EARTH MOVING

DIVISION 32 – EXTERIOR IMPROVEMENTS

321126 CRUSHED AGGREGATE BASE COURSE

DIVISION 33 – UTILITIES

331100 WATER DISTRIBUTION SYSTEMS

333100 SANITARY SEWER SYSTEMS

TABLE OF CONTENTS 000000 - 2

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LA POSA TYSON WASH LTVA JUNE 2021

WASTEWATER LAGOON – PHASE 2

VICINITY MAP

LOCATION MAP

CERTIFICATIONS 000105- 1

SECTION 000105 - CERTIFICATIONS

I hereby certify that this technical submission was prepared by me or under my direct supervision and responsible charge in accordance with the rules and regulations governing Architects and Engineers practicing in the State of Arizona. I am a duly registered Professional in the State of Arizona.

Discipline: Civil

Name: James Dale Hayson

Registration No.: 62210

Signature

CERTIFICATIONS 000105- 2

GEOTECHNICAL DATA 003132 - 1

SECTION 003132 – GEOTECHNICAL DATA

PART 1 - GENERAL

1.1 BORING NOTES

A. Data shown on boring logs is for the Bidders’ information. Bidder should be cognizant that materials between borings can vary from that shown on logs. Final and complete identification of all materials between borings can be verified only by Site excavation.

Bidder shall assume full responsibility for excavating all materials encountered during construction regardless of density or groundwater condition.

B. The boring logs are an exact copy of the originals made by photo process reproduction. This information was obtained for design purposes and is made available to Bidders so they may have the same information the designers used. This information is not intended as a substitute for Bidder’s personal investigations, interpretations, or judgment. Bidder may make his own soils investigation, but he must first obtain Government’s approval. Failure of Bidder to conduct his own investigation or to analyze available data shall not relieve Bidder of any responsibility in excavating difficult materials.

C. Water levels indicated on the boring logs are subject to seasonal and/or annual variations.

D. The original investigation report is available for Bidder’s inspection at Government’s office.

1.2 ATTACHMENTS

A. Geotechnical Report: Geotechnical Engineering Report – Proposed BLM La Posa WW Lagoons La Posa South LTVA, Quartzsite, Arizona; Prepared by Terracon and dated October 30, 2019; Terracon Project No. 65195142

END OF SECTION 003132

GEOTECHNICAL DATA 003132 - 2

REPORT COVER PAGE

Geotechnical Engineering Report

Proposed BLM La Posa WW Lagoons La Posa South LTVA

Quartzsite, Arizona

October 30, 2019 Terracon Project No. 65195142

Prepared for:

SEH, Inc.

Pueblo, Colorado

Prepared by:

Terracon Consultants, Inc.

4685 South Ash Avenue, Suite H-4 Tempe, Arizona

Terracon Consul tants, Inc. 4685 S. Ash Avenue Ste. H-4 Tempe, Ar izona 85282 P (480) 897 8200 F (480) 897 1133 terracon.com

REPORT COVER LET TER T O SIGN

October 30, 2019

SEH, Inc.

503 North Main Street, Suite 225 Pueblo, Colorado 81003

Attn: Mr. Jimmie Hayson Phone: (719) 423-7403 Email: jhayson@sehinc.com

Re: Geotechnical Engineering Report Proposed BLM La Posa WW Lagoons La Posa South LTVA Quartzsite, Arizona Terracon Project No. 65195142

Dear Mr. Hayson:

Terracon Consultants, Inc. (Terracon) has completed the Geotechnical Engineering services for the above referenced project. This study was performed in general accordance with Terracon Proposal No. P65195152 Revision No. 1 dated September 14, 2019. This report presents the findings of the subsurface exploration and provides geotechnical engineering recommendations concerning earthwork and the design and construction of foundations for the proposed project.

We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report or if we may be of further service, please contact us.

Sincerely, Terracon Consultants, Inc.

Eddy F. Ramirez, P.E. Donald R. Clark, P.E.

Geotechnical Project Manager Sr. Consultant/Sr. Principal

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REPORT TOPICS

INTRODUCTION

PROJECT DESCRIPTION

SITE CONDITIONS

EXPLORATION AND TESTING PROCEDURES

GEOTECHNICAL CHARACTERIZATION

CORROSIVITY

SEISMIC CONSIDERATIONS

GEOTECHNICAL OVERVIEW

SHALLOW FOUNDATIONS

LATERAL EARTH PRESSURES

FLOOR SLABS

EARTHWORK

GENERAL COMMENTS

MAP 1 LANDSCAPE

Note: This report was originally delivered in a web-based format. Orange Bold text in the report indicates a referenced section heading. The PDF version also includes hyperlinks which direct the reader to that section and clicking on the GeoReport logo will bring you back to this page. For more interactive features, please view your project online at client.terracon.com.

ATTACHMENTS

SITE LOCATION AND EXPLORATION PLANS

EXPLORATION RESULTS

(General Notes, Unified Soil Classification System, Boring Logs, and Laboratory Testing Results)

Note: Refer to each individual Attachment for a listing of contents.

http://client.terracon.com/

Proposed BLM La Posa WW Lagoons ■ Quartzsite, Arizona October 30, 2019 ■ Terracon Project No. 65195142

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REPORT SUMMARY

Topic 1 Overview Statement 2

Project Description

We understand the proposed project will consist of a new waste water treatment system, waste water lagoons, water well and well/pump house, water well, 15,000-gallon water storage tank and associated distribution lines, RV dump and fill stations, and electrical distribution.

Geotechnical Characterization

The subsurface conditions at the site generally consist of loose to very dense sand with variable amounts of silt, clay, and gravel, and medium dense to very dense poorly graded gravel with variable amounts of silt, clay, and sand to a depth of approximately 5 to 14 feet, followed by dense to very dense sand with variable amounts of silt, clay, and gravel and hard lean clay with sand to the full depth of exploration of 60½ feet.

Groundwater was not encountered to a maximum boring depth of 15½ feet.

Shallow Foundations

Shallow Foundations Shallow spread footings and concrete ring wall foundations can be utilized for the support of planned structures and water storage tanks on the project.

■ Maximum allowable bearing pressure = 3,000 psf with a minimum 18-inch embedment depth is recommended.

■ Expected settlements: 1 inch or less total, ¾ inch or less differential

■ Shallow foundations and concrete ring wall foundations should be supported on approved undisturbed native soils or compacted engineered fill, if required to raise site grades.

Mat/Slab Foundations Mat/slab foundations can be utilized for the proposed project.

■ Maximum allowable bearing pressure =3,000 psf with a minimum 12-inch embedment depth is recommended.

■ Expected settlements: 1 inch or less total

■ Mat/slab foundations should be supported on approved undisturbed native soils or compacted engineered fill, if required to raise site grades

Earthwork

■ No site preparation is required below shallow spread footings, concrete ring wall foundations, and mat/slab foundations. We recommend shallow spread footings, concrete ring wall foundations, and mat/slab foundations be supported on undisturbed native soils or engineered fill if required to raise site grades.

■ Subgrade soils beneath interior floor slabs and exterior slabs should be scarified, moisture conditioned and compacted to a minimum depth of 10 inches.

Slopes Compacted fill or excavation slopes constructed at 3H:1V side slopes and a maximum depth on the order of 5 feet below grade are considered safe for all soils on the site.

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Topic 1 Overview Statement 2

Erosion Considerations

Based on the engineering properties of the soils encountered in the test borings, the Erosion Index (ER) Factor (based on published data) for these soils is considered to be in the range of 4 to 6 (on a scale of 0 to 10). Based on this ER Index, moderate erosion would be predictable under high velocity water discharge on slopes or due to wave action in ponds. However, the interior slope face of embankments within the proposed ponds will be lined; therefore, the liners should provide adequate erosion control on the face of the embankment slopes. Consideration for erosion control on the exterior embankment slopes are provided in the report.

Seismic Considerations

Based on the site soil properties, the site is classified as Site Class D in accordance with Chapter 20 of ASCE 7 as required by the 2012/2015 IBC

General Comments

This section contains important information about the limitations of this geotechnical engineering report.

1. If the reader is reviewing this report as a pdf, the topics above can be used to access the appropriate section of the report by simply clicking on the topic itself.

2. This summary is for convenience only. It should be used in conjunction with the entire report for design purposes.

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INTRODUC TION

Geotechnical Engineering Report Proposed BLM La Posa WW Lagoons

La Posa South LTVA Quartzsite, Arizona

Terracon Project No. 65195142 October 30, 2019

INTRODUCTION

This report presents the results of our subsurface exploration and geotechnical engineering services performed for the proposed BLM La Posa WW Lagoons project to be located La Posa South LTVA in Quartzsite, Arizona. The purpose of these services is to provide information and geotechnical engineering recommendations relative to:

■ Subsurface soil conditions ■ Foundation design and construction

■ Groundwater conditions ■ Seismic site classification per IBC

■ Site preparation and earthwork ■ Lateral earth pressures

■ Excavation considerations

The geotechnical engineering scope of services for this project included the advancement of 7 test borings to depths ranging from approximately 19½ to 60½ feet below the existing ground surface, two percolation tests at a depth of approximately 4 feet below existing ground surface, laboratory testing from samples collected from our field exploration, geotechnical engineering analysis, and preparation of this report.

Maps showing the site and boring locations are shown on the attached Site Location and Exploration Plan sections, respectively. A log of each boring is included in the Exploration Results section of this report. The results of the laboratory testing performed on soil samples obtained from the site during the field exploration are included on the boring logs and as separate graphs in the Exploration Results section of this report.

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PROJECT DESCRIPTION

Item Description

Project Description

We understand the proposed project will consist of new waste water treatment system, waste water lagoons, water well and well/pump house, water well, 15,000-gallon water storage tank and associated distribution lines, RV dump and fill stations, and electrical distribution.

Proposed Structures

We anticipate the new well/pump house will be a wood-frame structure supported on shallow spread footings. We anticipate the waste water treatment system will consist of concrete structures supported on shallow spread footings and/or mat foundations. We anticipate the new water tank will be either a polyethylene or corrugated steel panels supported by a reinforced concrete ring wall foundation.

Proposed Waste Water Lagoons

Based on the information provided, we understand the planned construction will include 2 evaporation ponds. The maximum depth and planned side slope configurations of the evaporation ponds are unknown at the time this report was prepared. We anticipate the side slopes of the ponds will be approximately 3H:1V (horizontal: vertical). The ponds will be lined; however, details of the lining were not available.

Maximum Loads (assumed)

Load information for planned structures was not provided for the proposed project; therefore, the following are assumed maximum loads for the project.

Well/pump house structure

■ Columns: 50 kips

■ Walls: 2 to 4 kips per linear foot (klf)

■ Slabs: 150 pounds per square foot (psf)

Waste Water Treatment System

■ Columns: 100 kips

■ Walls: 4 to 5 kips per linear foot (klf)

■ Slabs: 150 pounds per square foot (psf)

15,000 Gallon Water Tank:

■ Total Weight: 125.5 kips

Grading/Slopes Topographically the site has a gentle slope across the ground surface;

however, we anticipated cuts and fills on the order of up to 2 to 4 feet may be required to bring the site to planned construction grade.

Below-Grade Structures

None are planned.

Free-Standing Retaining Walls

None are planned.

Pavements New gravel surface parking and access roads will be constructed. However, surfacing recommendations have been excluded from our scope of services.

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SITE CONDITIONS

The following description of site conditions is derived from our site visit in association with the field exploration and our review of publicly available geologic and topographic maps.

Item Description

Parcel Information The project site is located at the La Posa South LTVA in Quartzsite, Arizona.

See the attached Site Location and Exploration Plan for additional site information.

Existing Improvements The project site consists of native desert and is currently undeveloped.

Current Ground Cover The site is covered with bare soil and desert vegetation.

Existing Topography Based on information provided from Google Earth Pro, the site slopes down from the southeast to the northwest. There is approximately 25 feet in topographic relief across the site.

EXPLORATION AND TESTING PROCEDURES

Field Exploration

A total of 9 borings were drilled at the project site on September 4 and 5, 2019. The approximate boring locations at the project site are shown on the Exploration Plan, and the location and depth of the borings are summarized in the following table:

Number of Borings Boring ID Number Boring Depth (feet) Planned Location

5 B-1 thru B-4 20½ Waste Water Lagoons

2 B-5 and B-6 60½ Water Storage Tank/Pump House

1 B-7 19½ RV Dump Station

2 P-1 and P-2 4 Waste Water Lagoons (Percolation Testing)

Boring Layout and Elevations: Terracon personnel provided the boring layout. Coordinates were obtained by Terracon with a handheld GPS unit (estimated horizontal accuracy of about ±10 feet). If elevations and a more precise boring layout are desired, we recommend the borings be surveyed.

Subsurface Exploration Procedures: The borings were advanced with a truck-mounted D-120 drill rig utilizing 8-inch outside diameter hollow-stem augers. At selected intervals, samples of the subsurface materials were taken at each boring location by driving split-spoon (SPT) or ring-lined

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Responsive ■ Resourceful ■ Reliable 4 barrel samplers in general accordance with ASTM Standards. In the split-barrel sampling procedure, a standard 2-inch outer diameter split-barrel sampling spoon is driven into the ground by a 140-pound automatic hammer falling a distance of 30 inches. The number of blows required to advance the sampling spoon the last 12 inches of a normal 18-inch penetration is recorded as the Standard Penetration Test (SPT) resistance value. The SPT resistance values, also referred to as N-values, are indicated on the boring logs at the test depths. A 3-inch O.D. and 2.5-inch I.D. ring lined sampler was used for sampling at selected intervals in the soil borings. Ring-lined, split-barrel sampling procedures are similar to standard split spoon sampling procedure; however, blow counts are typically recorded for 6-inch intervals for a total of 12 inches of penetration. Bulk samples of subsurface materials were obtained from all the borings. Groundwater was not encountered during drilling and sampling. For safety purposes, all borings were backfilled with auger cuttings after their completion.

Our exploration team prepared field boring logs as part of the drilling operations. The sampling depths, penetration distances, and other sampling information were recorded on the field boring logs. These field logs included visual classifications of the materials encountered during drilling and our interpretation of the subsurface conditions between samples. The samples were placed in appropriate containers and taken to our soil laboratory for testing and classification by a geotechnical engineer. Final boring logs were prepared from the field logs. The final boring logs represent the geotechnical engineer's interpretation of the field logs and include modifications based on observations and tests of the samples in our laboratory.

Percolation Test Results

As part of the field exploration, Terracon performed two percolation tests at the location of the planned pond areas in general accordance with ADEQ requirements. The percolation tests were performed by drilling a 12-inch diameter percolation hole to a depth of approximately 4 feet below the existing ground surface. The percolation hole was cleaned, lined with a 10-inch PVC casing, and pre-soaked before testing. The annulus between the casing and the hole was backfilled and hand tamped with soil cuttings. After pre-soaking was completed, the hole was filled to a predetermined level. Then the percolation test was performed by measuring the amount of time for the water elevation to drop 1 inch. The percolation rates measured were reported in minutes per inch. The stabilized percolation rate is shown in the following table. The PVC casing was pulled out of the ground and backfilled with the soil cuttings upon completion.

Percolation Test Results

Test Hole Depth (feet) Soil Classification Infiltration Rate

(minutes/inch)

P-1 4 Silty Clayey Gravel with Sand 18

P-2 4 Silty Clayey Gravel with Sand 28

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It should be noted that siltation and vegetation growth along with other factors may affect the percolation rates within the proposed pond areas.

Laboratory Testing

Samples retrieved during the field exploration were taken to the laboratory for further observation by the project geotechnical engineer and were classified in accordance with the Unified Soil Classification System (USCS) as shown in Exploration Results section of this report. At that time, the field descriptions were confirmed or modified as necessary and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials.

General laboratory tests were conducted on selected soil samples and the test results are presented in the Exploration Results section of this report. These results were used for the geotechnical engineering analyses, and the development of foundation recommendations.

Laboratory tests were performed in general accordance with the applicable ASTM, local or other accepted standards.

Selected soil samples obtained from the site were tested for the following engineering properties:

n Atterberg Limits n Sieve Analysis n Moisture Content n Dry Density n Consolidation n Moisture Density Relationship n Remolded Swell n Direct Shear n Soluble Sulfate n pH n Soluble Chloride n Minimum Resistivity

GEOTECHNICAL CHARACTERIZATION

Geology

The project site is located in the Basin and Range physiographic province (1Cooley, 1967) of the North American Cordillera (2Stern, et al, 1979) of the southwestern United States. The southern portion of the Basin and Range province is situated along the southwestern flank of the Colorado Plateau and is bounded by the Sierra Nevada Mountains to the west. Formed during middle and late Tertiary time (100 to 15 million years ago), the Basin and Range province is dominated by fault-controlled topography. These mountain ranges and valleys have evolved from generally complex movements and associated erosional and depositional processes.

1 Cooley, M.E., 1967, Arizona Highway Geologic Map, Arizona Geological Society.

2 Stern, C.W., et al, 1979, Geological Evolution of North America, John Wiley & Sons, Santa Barbara, California.

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Typically, the ranges in these areas are of small areal extent but protrude significantly above adjacent wide alluviated plains and valleys. The basin rims are formed by the mountain ranges which consist of sedimentary, igneous and metamorphic materials which have been subjected to recurrent faulting and tilting, and in some places volcanic and intrusive events. As a result of erosion, the valleys have experienced partial infilling with sedimentary material which has been deposited as alluvial fans. Occasionally, the valleys may become interlocking as a result of coalescing alluvial fans which are referred to as bajadas.

Based on available U.S. Geological Survey (USGS) geological maps, surficial geologic conditions mapped at the site consist of Quaternary surficial deposits. This unit consists of unconsolidated to strongly consolidated alluvial and eolian deposits, including coarse, poorly sorted alluvial fan and terrace deposits on middle and upper piedmonts and along large drainages; sand, silt and clay on alluvial plains and playas; and wind-blown sand deposits.

Subsurface Profile

Specific conditions encountered at each boring location are indicated on the individual boring logs presented in the Exploration Results section of this report. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Based on conditions encountered in the borings, subsurface conditions at each project site can be generalized as follows:

Description Approximate Depth to Bottom of Stratum (feet) Material Description Relative Density /

Consistency

Stratum 1 5 to 14

Sand with variable amounts of silt, clay, and gravel, Gravel with variable amounts of silt, clay, and sand

Loose to Very Dense

Stratum 2 60½

(maximum depth explored)

Sand with variable amounts of silt, clay, and gravel, Lean Clay with Sand

Dense to Very Dense / Hard

Laboratory tests were conducted on selected soil samples obtained from the project site and the test results are presented in the Exploration Results section of this report. Test results indicate the near surface sand and gravel soils exhibit non-plastic to low plasticity characteristics.

When water was added to a sample of laboratory compacted on-site near surface silty clayey sand soils, the compacted soils exhibited low expansive potential when subjected to light loading conditions such as those imposed by lightly loaded mat/slab foundations.

In response to wetting of relatively undisturbed samples while supporting typical foundation loads, the near surface soils exhibited low hydro-compaction (collapse) potential at in-situ moisture

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Direct shear tests were performed on undisturbed samples obtained during the field exploration and the results indicated peak friction angles of 48 and 54 degrees and cohesion values of 0 and 48 psf at the maximum shear stress. Residual friction angles corresponding to maximum displacement under direct shear testing were 46 and 52 degrees with a cohesion value of 0 psf.

Groundwater Conditions

Groundwater was not observed in any of the test borings at the time of our field exploration, nor when checked upon completion of drilling. These observations represent groundwater conditions at the time of the field exploration and may not be indicative of other times, or the conditions at other locations. Groundwater conditions can change with varying seasonal and weather conditions, and other factors.

Based on information obtained from the Arizona Department of Water Resources – Groundwater Data website (https://gisweb.azwater.gov/waterresourcedata/GWSI.aspx), the depth to regional groundwater near the project site was measured to be approximately 38 feet below the ground surface at an Arizona Department of Water Resources (ADWR) monitored well sites (Local I.D.:

B-04-19 33CCA) located approximately 3,000 feet northwest of the project site.

CORROSIVITY

The following table lists the results of laboratory soluble sulfate, soluble chloride, electrical resistivity, and pH testing. The values may be used to estimate potential corrosive characteristics of the on-site soils with respect to contact with the various underground materials which will be used for project construction.

Corrosivity Test Results Summary

Location Sample Depth (feet)

Soil Description pH Electrical Resistivity

(Ω-cm)

Soluble Sulfate Content (ppm)

Soluble Chloride Content (ppm)

B-4 0 – 5 Silty Sand with Gravel 8.2 173 402 2,083

B-5 0 – 5 Silty Clayey Sand 8.3 253 354 558

B-7 0 – 5 Silty Clayey Sand with Gravel 8.1 94 273 2,375

Results of soluble sulfate testing indicate that samples of the on-site soils tested classify as S0 according to Table 19.3.1.1 of Section 318 of the American Concrete Institute (ACI) Building Code https://gisweb.azwater.gov/waterresourcedata/GWSI.aspx

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Requirements for Structural Concrete. Concrete should be designed in accordance with the provisions of the ACI Building Code Requirements for Structural Concrete, Section 318, Chapter 19.

These values should be used to help determine potential corrosive characteristics of the on-site soils with respect to contact with the various underground materials which will be used for project construction. Refer to Summary of Laboratory Results contained in Exploration Results section for the complete results of the corrosivity testing performed on the site soils in conjunction with this geotechnical exploration. The corrosion information presented is specific to the samples tested. If the actual soils that will be in contact with the structures at the site are different than those tested, then additional corrosion testing should be performed. Terracon is not a corrosion engineer, and our scope of work was limited to performing corrosion laboratory tests on selected samples, presenting these results, and providing a brief comparison of the results to selected criteria. A qualified corrosion engineer should be consulted if corrosion of underground utilities and structures is a concern.

SEISMIC CONSIDERATIONS

The seismic design requirements for buildings and other structures are based on Seismic Design Category. Site Classification is required to determine the Seismic Design Category for a structure.

The Site Classification is based on the upper 100 feet of the site profile defined by a weighted average value of either shear wave velocity, standard penetration resistance, or undrained shear strength in accordance with Section 20.4 of ASCE 7 and the International Building Code (IBC).

Based on the soil properties encountered at the site and as described on the exploration logs and results, it is our professional opinion that the Seismic Site Classification is D. Subsurface explorations at this site were extended to a maximum depth of 60½ feet. The site properties below the boring depth to 100 feet were estimated based on our experience and knowledge of geologic conditions of the general area. Additional deeper borings or geophysical testing may be performed to further evaluate the conditions below the current boring depths and evaluate if a different seismic site classification for the site is appropriate.

GEOTECHNICAL OVERVIEW

The project site appears suitable for the proposed construction based upon geotechnical conditions encountered in the borings, and provided our recommendations contained in this report are properly implemented in the design and construction. The following is a summary of the key geotechnical considerations for this project:

October 30, 2019 ■ Terracon Project No. 65195142

Responsive ■ Resourceful ■ Reliable 9 n The on-site near surface at the project site soils generally consist of sand and gravel with variable amounts of silt and clay. Field penetration test results near shallow foundation depths indicate that the relative density of the near surface sand and gravel soils is generally loose to very dense.

n Shallow spread footings, concrete ring wall foundations, and mat/slab foundations bearing on approved native undisturbed soils are recommended for support of the proposed structures, tanks, and equipment. The base of all foundation excavations should be free of water and loose soil, prior to placing concrete. Extremely wet, loose or disturbed material in the bottom of the foundation excavations should be removed before foundation concrete is placed. Should the soils at bearing level become excessively disturbed or saturated, the affected soil should be removed prior to placing concrete.

n The on-site soils are considered suitable for use as engineered fill in all construction areas.

n We anticipate the embankment side slopes in the evaporation ponds will be constructed at a slope ratio of 3H:1V. Compacted fill or excavation slopes constructed at these planned slope ratios and a maximum depth on the order of 5 feet below grade are considered safe for all soils on the site.

n It is anticipated that shallow excavations for the proposed construction can be accomplished with conventional earthmoving equipment.

n Based on the engineering properties of the soils encountered in the test borings, the Erosion Index (ER) Factor (based on published data) for these soils is considered to be in the range of 4 to 6 (on a scale of 0 to 10). Based on this ER Index, moderate erosion would be predictable under high velocity water discharge on slopes or due to wave action in ponds. However, the interior slope face of embankments within the proposed ponds will be lined; therefore, the liners should provide adequate erosion control on the face of the embankment slopes. Consideration for erosion control on the exterior embankment slopes are provided in the report.

n Based on the site soil properties, the site is classified as Site Class D in accordance with Chapter 20 of ASCE 7 as required by the 2012 International Building Code.

Geotechnical engineering recommendations for foundation systems, support of pond liners, embankments, and other earth connected phases of the project are outlined below. The recommendations contained in this report are based upon the results of field and laboratory testing (included in the Exploration Results section), engineering analyses, and our current understanding of the proposed project.

The General Comments section provides an understanding of the report limitations.

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SHALLOW FOUNDATIONS

If the project site has been prepared in accordance with the requirements noted in Earthwork, the following design parameters are applicable for shallow foundations for proposed project.

Design Parameters – Spread Footings and Concrete Ring Wall Foundations, Design Item Description/Recommendations

Maximum Net Allowable

Bearing Pressure 1,2 3,000 psf

Minimum Embedment Depth Below finished grade 3 18 inches

Bearing Material Spread footings and concrete ring wall foundations may be supported on undisturbed native soils or engineered fill if required to raise site grades.

Minimum footing dimensions Isolated Column Footings: 24 inches Continuous Wall Footings: 18 inches

Estimated total settlement 2 1 inch or less

Estimated differential settlement 2 ¾ of the total settlement

1. The maximum net allowable bearing pressure is the pressure in excess of the minimum surrounding overburden pressure at the foundation base elevation. The allowable bearing pressure may be increased by one-third when considering the alternative load combinations of Section 1605.3.2 of the 2012 International Building Code, however, it should not be increased when loads are determined by the basic allowable stress design load combinations of Section 1605.3.1.

2. Values provided are for maximum loads noted in the Project Description.

3. Finished grade is defined as the lowest adjacent grade within 5 feet of the foundation for perimeter (or exterior) footings or concrete ring wall foundations and finished floor level for interior footings.

Footings, foundations, and walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities in walls is recommended.

Foundation excavations should be observed by the geotechnical engineer. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required.

Mat/Slab Foundations

The proposed structures may be supported on mat/slab foundations. The following design parameters are applicable for mat/slab foundations. Specific attention should be given to positive drainage away from the structures.

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Design Item Description/Recommendations Foundation Type Mat/Slab Foundations

Maximum Design Contact Stress1 Any practical value up to 3,000 psf

Bearing Material Mat/slab foundations may be supported on undisturbed native soils or engineered fill if required to raise site grades

Design Modulus of Subgrade Reaction, k 250 pci

Minimum Width 4 feet

Modulus Correction Factor2 kc=k((b+1)/2b)

Minimum Embedment Depth 12 inches

Total Estimated Settlement 1 inch or less

Differential Settlement ¾-inch over 4 feet

1.The maximum net allowable bearing pressure is the pressure in excess of the minimum surrounding overburden pressure at the foundation base elevation. The allowable bearing pressure may be increased by one-third when considering the alternative load combinations of Section 1605.3.2 of the 2012 International Building Code, however, it should not be increased when loads are determined by the basic allowable stress design load combinations of Section 1605.3.1.

2. It is common to reduce the k-value to account for dimensional effects of large loaded areas. Where kc is the corrected or design modulus value and b is the mat width (short dimension) or tributary loaded area.

Mat/slab foundations should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities in walls is recommended.

Foundation excavations should be observed by the geotechnical engineer. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required.

Foundation Construction Considerations

As noted in Earthwork section of this report, foundation excavations should be evaluated and approved under the direction of the Geotechnical Engineer. The base of all foundation excavations should be free of water and loose soil, prior to placing concrete. Concrete should be placed soon after excavating to reduce bearing soil disturbance. Care should be taken to prevent wetting or drying of the bearing materials during construction. Extremely wet, loose or disturbed material in the bottom of the footing excavations should be removed before foundation concrete is placed. Should the soils at bearing level become excessively disturbed or saturated, the affected soil should be removed prior to placing concrete.

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LATERAL EARTH PRESSURES

Design Parameters

The lateral earth pressure recommendations herein are applicable to the design of foundations and rigid retaining walls subject to slight rotation, such as cantilever, or gravity type concrete walls.

Earth Pressure Design Case1 Design Recommenations2,4

Active Case 35 psf/ft

Passive Case 375 psf/ft At-Rest Case 55 psf/ft

Coefficient of Base Friction 0.453

Total Unit Weight 115 pcf

1. For active earth pressure, wall must rotate about base, with top lateral movements 0.002 H to 0.004 H, where H is wall height. For passive earth pressure, wall must move horizontally to mobilize resistance.

2. The design values are based on utilizing on-site soils as backfill placed and compacted as outlined in the

Earthwork section of this report. Compaction of each lift adjacent to walls should be accomplished with hand-operated tampers or other lightweight compactors.

3. The coefficient of base sliding should be reduced to 0.30 when used in conjunction with passive pressure.

4. The lateral earth pressures herein do not include any factor of safety, they assume drained conditions and a horizontal backfill, and they are not applicable for submerged soils/hydrostatic loading. Additional recommendations may be necessary if such conditions are to be included in the design.

FLOOR SLABS

Floor slabs (non-pavement areas) should be designed based on the following geotechnical recommendations:

Floor Slab Design Parameters

Item Description Interior floor system Slab-on-grade concrete.

Subbase 4 inches of compacted aggregate base course materials

Floor slab support A minimum of 10 inches of engineered fill placed in accordance with the Earthwork section of this report.

Modulus of subgrade reaction1 250 pounds per square inch per inch (psi/in) for point loads

1. Modulus of subgrade reaction is an estimated value based upon our experience with the subgrade condition, the requirements noted in Earthwork section of this report, and the floor slab support as noted in this table.

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Additional floor slab design and construction recommendations are as follows:

n Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement.

n Control joints should be provided in slabs to control the location and extent of cracking.

n Other design and construction considerations, as outlined in the ACI Design Manual, Section 302.1R are recommended.

n Some differential movement of a slab-on-grade floor system is possible on long-term settlement of the underlying materials. To reduce potential slab movements, the subgrade soils should be prepared as outlined in the Earthwork section of this report.

n The use of a vapor retarder or barrier should be considered beneath concrete slabs on grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab designer and slab contractor should refer to ACI 302 and ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder/barrier.

Floor Slab Construction Considerations

Finished subgrade within and for at least 10 feet beyond the floor slab should be protected from traffic, rutting, or other disturbance and maintained in a relatively moist condition until floor slabs are constructed. If the subgrade should become damaged or desiccated prior to construction of floor slabs, the affected material should be removed and engineered fill should be added to replace the resulting excavation. Final conditioning of the finished subgrade should be performed immediately prior to placement of the floor slab support course.

The Geotechnical Engineer should approve the condition of the floor slab subgrades immediately prior to placement of the floor slab support course, reinforcing steel and concrete. Attention should be paid to high traffic areas that were rutted and disturbed earlier, and to areas where backfilled trenches are located.

EARTHWORK

The following presents recommendations for site preparation, excavation, subgrade preparation and placement of engineered fills as well as erosion control and slope configurations on the project. The recommendations presented for design and construction of earth supported elements including foundations, floor slabs, pond liners, and embankments are contingent upon following the recommendations outlined in this section.

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Earthwork on each project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during the construction of each project.

Site Preparation

Strip and remove existing vegetation, and other deleterious materials from proposed structures, tanks, equipment, and pond areas. Exposed surfaces should be free of mounds and depressions which could prevent uniform compaction. The sites should be initially graded to create a relatively flat surface to receive fill, and to provide for a relatively uniform thickness of fill beneath the proposed structures, tanks, equipment, and ponds.

Although evidence of fills or underground facilities such as septic tanks, cesspools, basements, and utilities was not observed during the site reconnaissance at each project site, such features could be encountered during construction. If unexpected fills or underground facilities are encountered, such features should be removed, and the excavation thoroughly cleaned prior to backfill placement and/or construction

Subgrade Preparation

Shallow spread footings, concrete ring wall foundations, and mat/slab foundations bearing on approved undisturbed native soils are recommended for support of the proposed structures, tanks, and equipment. If unsuitable bearing materials are encountered during construction at the base of the planned foundation excavations, the unsuitable material should be removed to the extents recommended by the geotechnical engineer. The proposed foundations could either bear directly on deeper approved native undisturbed soils or the deepened excavations could be backfilled to planned foundation bearing depth with engineered fill or with lean concrete placed in the excavations.

Subgrade soils beneath interior floor slabs and exterior slabs should be scarified, moisture conditioned and compacted to a minimum depth of 10 inches. The moisture content and compaction of subgrade soils should be maintained until slab construction.

Fill Material Types

All fill materials should be inorganic soils free of vegetation, debris, and fragments larger than four inches in size. Pea gravel or other similar non-cementitious, poorly-graded materials should not be used as fill or backfill without the prior approval of the geotechnical engineer.

Clean on-site soils or approved imported materials may be used as fill material for the following:

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Fill Type 1 USCS Classification Acceptable Location for Placement

On-Site Soils SM, SC-SM, GP-GM, GP-GC

The near-surface on-site soils are considered suitable for use as engineered fill.

Low Volume Change:

Imported Material Varies All locations and elevations

1. Controlled, compacted fill should consist of approved materials that are free of organic matter, debris, and oversized materials. A sample of each material type should be submitted to the geotechnical engineer for evaluation.

Imported soils for use as fill material (if required) on the project should conform to low volume change materials as indicated in the following specifications:

Percent Finer by Weight Gradation (ASTM C 136)

4" No. 4 Sieve ..................................................................................... 50-100 No. 200 Sieve ............................................................ 15 (min) to 45 (max) n Liquid Limit ....................................................................... 30 (max) n Plasticity Index ................................................................. 12 (max) n Maximum expansive potential (%)* ............................................ 1.5

*Measured on a sample compacted to approximately 95 percent of the ASTM D698 maximum dry density at about 3 percent below optimum water content. The sample is confined under a 100 psf surcharge and submerged/inundated.

Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift.

Fill lifts should not exceed 10 inches loose thickness.

Fill Compaction Requirements

Engineered fill should meet the following compaction and moisture requirements:

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Material Type and Location

Per the Standard Proctor Test (ASTM D 698)

Compaction Requirement

Range of Moisture Contents for Compaction (referenced from optimum moisture content) Minimum Maximum

On-site and imported soils:

Beneath foundations 95 -2% +3% Beneath floor slabs 95 -2% +3%

Embankment fills and general site grading 95 -2% +3% Aggregate base (beneath concrete slabs or mat/slab foundations)

95 -2% +3%

Miscellaneous backfill 95 -3% +3%

1. The moisture content and compaction should be measured for each lift of engineered fill during placement.

Should the results of the in-place density tests indicate the specified moisture or compaction limits have not been met, the area represented by the test should be reworked and retested as required until the specified moisture and compaction requirements are achieved.

Utility Trench Backfill

Utility trenches are a common source of water infiltration and migration. Utility trenches penetrating beneath the structures, tanks, and equipment should be effectively sealed to restrict water intrusion and flow through the trenches, which could migrate below the structures, tanks, and equipment. The trench should provide an effective trench plug that extends at least 5 feet from the face of the structure exterior. The plug material should consist of cementitious flowable fill or low permeability clay. The trench plug material should be placed to surround the utility line.

If used, the clay trench plug material should be placed and compacted to comply with the water content and compaction recommendations for structural fill stated previously in this report.

Erosion Considerations

Erosion considerations for the project, based on geotechnical considerations, have been based on predicted erosion rating of the soils (as classified by various departments of transportation), and general guidelines provided in the ADOT Erosion and Pollution Control Manual (2012).

Based on the engineering properties of the soils encountered in the test borings, the Erosion Index (ER) Factor (based on published data) for these soils is considered to be in the range of 4 to 6 (on a scale of 0 to 10). Soils with an ER Index in the range of 4 to 6 are described as “Moderately cohesive to friable soil.” Based on this ER Index, moderate erosion would be predictable under high velocity water flow discharge of the face of embankment slopes or wave action. As currently planned, the interior slopes on the embankments within the proposed ponds

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Depending on design flow velocities of discharge of storm water on exterior embankment slopes (where liners will not be constructed), the engineering properties of the materials at the site indicate that some form of permanent erosion control should be considered in the final design unless periodic maintenance is undertaken with respect to the slopes.

Based on an ER Index of 4 to 6, recommended considerations for erosion control measures, considering discharge velocity, are summarized as follows:

Preliminary Considerations for Erosion Control

Water Velocity (fps) Recommended Slope Protection

2 or less Vegetated or exposed soil

2 to 5 Soil mats

5 to 8 Permanent soil reinforcing mats

8 or greater Shotcrete, grouted rip-rap or soil cement

Slopes

We anticipate the embankment side slopes in the evaporation ponds will be constructed at a slope ratio of 3H:1V. Compacted fill or excavation slopes constructed at this planned slope ratio and a maximum depth on the order of 5 feet below grade is considered safe for all soils on the site.

If steeper slopes are required for site development, stability analyses should be completed to design the grading plan.

The face of all slopes should be compacted to the minimum specification for fill embankments.

Alternately, fill slopes can be over-built and trimmed to compacted material.

Grading and Drainage

Positive drainage…