Geotechnical_Report.pdf

Terracon Consul tants, Inc. 11849 West Execut ive Dr ive, Suite G Boise, Idaho 83713 P [208] 323 9520 F [208] 323 9592 terracon.com

July 1, 2021

Six Mile Engineering, PA 704 E. United Heritage Court, Suite 204 Meridian, Idaho 83642

Attn: Ms. Leah G. Kelsey, P.E., PTOE E: Leah.Kelsey@sixmile.com

Re: Geotechnical Engineering Letter Report Summary of Piezometers and Infiltration Rate Tests Cloverdale Rd, Victory Rd to Overland Rd Boise, Ada County, Idaho ACHD Project No. 521021, ACHD Purchase Order No. 63055853 Terracon Project No. 62215009

Dear Ms. Kelsey:

This letter report summarizes the results of Terracon’s services for the referenced project. The Ada County Highway District (ACHD) plans to widen Cloverdale Road to five lanes between Victory Road and Overland Road intersection. The proposed project will include stormwater management improvements. The purpose of Terracon’s services described in this letter is to provide geotechnical information for the proposed stormwater improvements.

Terracon’s services included installing three piezometers and performing infiltration rate testing at three locations that were provided to us. Site Location and Exploration Plan maps are attached to this letter report.

Field Exploration Borings P-1, P-2, and P-3 were drilled to explore subsurface conditions and to install piezometers in the three areas identified for proposed stormwater facility. The piezometers extended to depths of about 17½ feet beneath the existing ground surface. Additional borings, labeled I-1, I-2, I-2(B), I-2(C), and I-3, were drilled near the locations of piezometers P-1, P-2, and P-3, respectively, for use as infiltration rate test holes, and they extended to depths ranging from about 4 to 10 feet below the existing ground surface.

Terracon’s scope of services included performing infiltration tests at the locations of P-1/I-1 and P-3/I-3 in borings using falling head test methods within ACHD’s right-of-way. At the location of P-2/I-2, our scope included performing a small-scale pilot infiltration test in a backhoe test pit within private property. However, we understand that ACHD was unable to receive permission to access the private property at that location. Therefore, Terracon was asked to perform the test

Geotechnical Engineering Letter Report Summary of Piezometers and Infiltration Rate Tests ■ Boise, ID July 1, 2021 ■ ACHD Project No. 201889 Terracon Project No. 62215009

Responsive ■ Resourceful ■ Reliable 2 at the location of P-2/I-2 using the borehole method. This test method is not included in the methods described in Appendix B of Section 8200 of the ACHD Policy manual. However, it is a test that can be performed where space is limited and it can be performed at greater depths. We understand the borehole test method will be accepted for this project

Due to high groundwater and soils that appeared unfavorable for infiltration at the location of boring P-2/I-2, additional percolation test borings were drilled and performed (borings I-2(B) and I-2(C)).

The general piezometer and feasibility infiltration test locations were provided to us by Six Mile Engineering, PA (6ME) and adjusted by Terracon based on locations of overhead and buried utilities, shoulder width, and traffic safety. The locations of the borings are shown on the attached Exploration Plan. The boring locations were determined in the field using a recreational grade GPS having an approximate accuracy of about 20 feet. The locations of the borings should be considered accurate only to the degree implied by the means and methods used to define them.

If elevations or more accurate locations are needed, the borings should be surveyed by the project surveyor. A Terracon field engineer recorded logs of the borings during the drilling operations.

Copies of the boring logs are attached.

Disturbed soil samples were obtained from the borings at various depths using a 2-inch-outside-diameter split-spoon sampler driven in general accordance with the standard penetration test (SPT). The result of the SPT is an N-value. The N-value is the number of blows from a 140-pound hammer falling from a height of 30 inches that are required to drive the split-spoon sampler the last 12 inches of an 18-inch interval (or the distance indicated). N-values are shown on the boring logs. Descriptions of the materials encountered are presented on the boring logs.

The N-value provides a reasonable qualitative estimate of the relative in-place density of non-cemented sandy type materials. However, the N-value only provides an indication of the relative stiffness of cohesive materials, since the penetration resistance of these soils may be affected by the moisture content. Considerable care must be exercised in interpreting the N-value in gravelly soils, particularly where the size of the gravel particles exceeds the inside diameter of the sampling spoon.

The piezometers were constructed by placing slotted PVC pipe in the boring. The annular space between the wall of the borehole and the pipe was backfilled with sand. A bentonite seal was placed above this sand backfill and a flush-mount cover was set in concrete over the top of the piezometer. Abandonment of the piezometers was not included in our scope of services.

July 1, 2021 ■ ACHD Project No. 201889 Terracon Project No. 62215009

Responsive ■ Resourceful ■ Reliable 3

Soil Conditions Soil conditions encountered at the exploration locations are indicated on the attached logs.

Stratification boundaries on the logs represent the approximate locations of changes in soil types;

in-situ, the transition between materials may be gradual.

Moisture content and gradation analysis tests were performed on samples selected by Terracon.

Test results are contained on the boring logs and on a separate graph.

Groundwater The borings were monitored during drilling for the presence of groundwater. Groundwater was not encountered in the piezometers when they were drilled and installed on April 15, 2021. At the time of the later mobilization to install the infiltration tests at the location of P-2/I-2 groundwater was encountered at a shallower elevation in boring I-2 than in the nearby piezometer P-2, possibly due to a perched groundwater condition, associated with the nearby canal, in soil layers above the slotted portion of the piezometer’s pipe. A summary of the measured groundwater levels are presented below.

Fluctuations in groundwater depth may occur due to seasonal variations in the amount of irrigation, rainfall, runoff, amount of water in the nearby canal, and other factors not evident at the time the borings were performed. Evaluation of these factors is beyond the scope of this exploration. We understand that future groundwater measurements will be recorded by ACHD.

Infiltration Rate Testing Infiltration rate tests were performed in borings I-1, I-2(B), I-2(C), and I-3. Due to groundwater encountered in boring I-2, a percolation test was not performed in that boring. Each infiltration test was performed in a 5-inch diameter solid pipe that was placed within the test boring. Bentonite was placed in the annular space around the pipe to act as a seal. Each test hole was presoaked the day prior to testing. The tests were performed with a head of water of approximately 24 inches. The test results are summarized in the following table with the infiltration rate reported in inches per hour.

Date Piezometer / Boring

P-1 P-2 I-2 P-3 4/15/2021 Not Encountered Not Encountered - Not Encountered 5/27/2021 - 11.6 6.5 - 6/11/2021 17.0 11.7 - Not Encountered

1. Boring I-2 was drilled for infiltration testing on 5/27/2021. Due to groundwater encountered in the boring, a infiltration test was not performed and the boring was backfilled on the same day.

July 1, 2021 ■ ACHD Project No. 201889 Terracon Project No. 62215009

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Infiltration Test Boring

Approximate Depth of Test 1 Soil Type at Depth of Test

Measured Infiltration

Rate I-1 10 Well-Graded Sand with Silt and Gravel (SW-SM) >20

I-2(B) 2 4 Fill, Mixture of clay with sand and gravel 0

I-2(C) 2 5½ Sandy Silt (ML) <0.25

I-3 7½ 3 Silty Sand with Gravel (SM) 10

1. Depth below the existing ground surface.

2. Due to water encountered in boring I-2 at a depth of about 6½ feet, infiltration tests at this location were performed above the encountered water.

3. Within boring P-3, a layer of sandy silt was encountered from a depth of about 9½ feet to 13½ feet. It is our opinion this sandy silt layer will likely have a lower infiltration rate than the silty sand with gravel that was tested in boring I-3 and would limit the performance of an infiltration facility set above this layer. Therefore, at the location of I-3, infiltration facilities should extend into the gravel with sand layer encountered at a depth of about 13½ feet below the existing ground surface in boring P-3.

These results represent the tests at the depths and locations indicated, as described above. The actual infiltration rates used should be determined by the designer by applying an appropriate factor of safety. In accordance with the ACHD Policy Manual, the minimum factor of safety selected should be 2. With time, the bottoms of infiltration systems tend to plug with organics, sediments, and other debris. Long-term maintenance will likely be required to remove these deleterious materials to help reduce decreases in the actual infiltration rate. In addition, the infiltration rate may be affected by the following factors, which should be considered when selecting the factor of safety:

Test Procedures: The feasibility infiltration tests were performed through a 5-inch diameter pipe.

Infiltration rates in large storm water infiltration systems may be different than measured in the relatively small test area.

Water Quality: The infiltration tests were performed with clear water, whereas the storm water will likely not be clear, but may contain organics, fines, and grease/oil. The presence of these deleterious materials will tend to decrease the rate that water percolates through the infiltration system. Design of the storm water infiltration system should account for the presence of these materials and should incorporate structures/devices to remove these deleterious materials.

Soil Variability: Based on the soils encountered in our exploration, we expect the infiltration rates of the soils could be different than measured in the field due to variations in fines content, soil type, and cementation. The design elevation and size of the proposed infiltration system should account for this expected variability in the infiltration rate.

July 1, 2021 ■ ACHD Project No. 201889 Terracon Project No. 62215009

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Closure The information presented in this report is based upon the data obtained from the borings drilled at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided.

The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken.

This report has been prepared for the exclusive use of Six Mile Engineering and the Ada County Highway District for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.

We appreciate the opportunity to work with you on this project. Please call our office if you have any questions regarding this letter.

Sincerely, Terracon Consultants, Inc.

Mohsen Amirmojahedi, PhD, E.I. Ryan J. Olsen, P.E.

Project Professional Geotechnical Department Manager

Attachments:

A-1 Site Location Diagram A-2 Exploration Plan Diagram A-3 Boring Logs A-4 Grain Size Distribution

July 1, 2021 ■ ACHD Project No. 201889 Terracon Project No. 62215009

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A-5 General Notes A-6 Unified Soil Classification System

SITE LOCATION

Cloverdale Rd, Victory Rd to Overland Rd ■ Boise, ID

June 14, 2021 ■ ACHD Project No. 201889

Terracon Project No. 62215009

TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVE (2021). DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS

NOT INTENDED FOR CONSTRUCTION PURPOSES

SITE

EXPLORATION PLAN

EXPLORATION PLAN

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS

NOT INTENDED FOR CONSTRUCTION PURPOSES

AERIAL PHOTOGRAPHY PROVIDED

BY MICROSOFT BING MAPS (2021)

3-5-4 N=9

5-5-6 N=11

15-14-21 N=35

13-15-16 N=31

1.3

1.1

1.5

1 103.6

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

LEAN CLAY (CL), dark brown, stiff

SILTY SAND (SM), trace gravel, weak cemented particles, light brown, dense

SILTY SAND WITH GRAVEL (SM), light brown

WELL GRADED SAND WITH SILT AND GRAVEL (SW-SM), with cobbles, light brown, dense

Boring Terminated at 10 Feet

2.0

4.5

7.5

8.5

10.0

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5882° Longitude: -116.3343°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring completed as infiltration rate test.

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. I-1

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 04-15-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 04-15-2021

11849 W Executive Dr Ste G Boise, ID

WATER LEVEL OBSERVATIONS

No free water observed

S A

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4-10-8 N=18

2-2-2 N=4

0-2-4 N=6

7-27-44 N=71

1.2

1.3

1.1

1.3

18.8

21.4

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

SANDY LEAN CLAY (CL), dark brown, soft to medium stiff

CLAYEY SAND (SC), trace gravel, brown, medium stiff

SILTY SAND WITH GRAVEL (SM), brown, loose to medium dense with cobbles, very dense

Boring Terminated at 9.5 Feet

3.0

4.5

6.0

9.5

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5844° Longitude: -116.3342°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. I-2

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 05-27-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 05-27-2021

11849 W Executive Dr Ste G Boise, ID

7.5 ft while drilling

6.5 ft after drill

WATER LEVEL OBSERVATIONS

S A

M P

LE

T

Y

7-8-14 N=22

2-2-3 N=5

1.5

0.5

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

Boring Terminated at 4 Feet 4.0

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5844° Longitude: -116.3342°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring completed as infiltration rate test.

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. I-2 (B)

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 05-27-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 05-27-2021

11849 W Executive Dr Ste G Boise, ID

WATER LEVEL OBSERVATIONS

No free water observed

S A

M P

LE

T

Y

10-5-18 N=23

5-6-3 N=9

1-2-2 N=4

1.1

0.6

1.3

6123.3 30-23-7

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

SANDY SILT (ML), dark brown, soft to medium stiff

Boring Terminated at 5.5 Feet

4.5

5.5

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5842° Longitude: -116.3342°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring completed as infiltration rate test.

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. I-2 (C)

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 05-27-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 05-27-2021

11849 W Executive Dr Ste G Boise, ID

WATER LEVEL OBSERVATIONS

No free water observed

S A

M P

LE

T

Y

1-2-4 N=6

2-5-6 N=11

13-14-13 N=27

1.1

1.4 1521.7

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

SANDY SILT (ML), brown, stiff

SILTY SAND WITH GRAVEL (SM), gravel sized pieces in sample are strongly cemented particles, light brown, medium dense, cemented zones

Boring Terminated at 7.5 Feet

3.5

5.0

7.5

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

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ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5806° Longitude: -116.3343°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring completed as infiltration rate test.

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. I-3

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 04-15-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 04-15-2021

11849 W Executive Dr Ste G Boise, ID

WATER LEVEL OBSERVATIONS

No free water observed

S A

M P

LE

T

Y

4-7-9 N=16

4-5-6 N=11

22-23-26 N=49

18-23-24 N=47

13-21-31 N=52

50/5"

0.6

1.4

1.5

0.9

1.2

0.4

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

LEAN CLAY (CL), brown, stiff

SILTY SAND (SM), trace gravel, light brown, dense

SILTY SAND WITH GRAVEL (SM), light brown, dense

WELL GRADED GRAVEL WITH SILT AND SAND (GW-GM), with cobbles, light brown, very dense

Boring Terminated at 17.5 Feet

2.0

4.5

7.5

8.5

17.5

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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LT

S

R E

C O

V E

R Y

F t.)

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5882° Longitude: -116.3342°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring completed as piezometer.

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. P-1

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 04-15-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 04-15-2021

11849 W Executive Dr Ste G Boise, ID

No free water observed while drilling

No free water observed on 4/16/2021

17 ft on 6/11/2021

WATER LEVEL OBSERVATIONS

S A

M P

LE

T

Y

4-10-15 N=25

3-3-3 N=6

1-3-3 N=6

23-50/5"

23-34-50 N=84

24-50/3"

0.9

0.8

0.9

1.5

0.6

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

CLAYEY SAND (SC), trace gravel, brown, loose

SILTY SAND WITH GRAVEL (SM), with cobbles, brown and white, very dense

INTERBEDDED SANDY LEAN CLAY LENSES FROM 9 TO 13 FT

POORLY GRADED GRAVEL WITH SILT AND SAND (GP-GM), with cobbles, brown and white, very dense

Boring Terminated at 17.5 Feet

4.5

6.5

13.0

17.5

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

T

G E

O S

M A

R T

L O

G -N

O W

E

LL

C

LO

V

E R

D A

LE

R

D , V

I.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

/1

/2

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

F

IE

LD

T

E S

T R

E S

U

LT

S

R E

C O

V E

R Y

F t.)

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5844° Longitude: -116.3342°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring completed as piezometer.

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. P-2

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 04-15-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 04-15-2021

11849 W Executive Dr Ste G Boise, ID

No free water observed while drilling

11.6 ft on 5/27/2021

11.7 ft on 6/11/2021

WATER LEVEL OBSERVATIONS

S A

M P

LE

T

Y

2-2-2 N=4

2-2-2 N=4

8-11-12 N=23

15-17-15 N=32

11-13-13 N=26

27-20-47 N=67

0.9

1.5

1.5

1.5

FILL - MIXTURES OF SANDY LEAN CLAY AND CLAYEY SAND WITH

VARIABLE AMOUNTS OF GRAVEL , brown

SANDY SILT (ML), brown, stiff

SILTY SAND WITH GRAVEL (SM), gravel sized pieces in sample are strongly cemented particles, brown, medium dense, cemented zones dense, grades less silt

SANDY SILT (ML), with cemented particles, brown, very stiff

POORLY GRADED GRAVEL WITH SILT AND SAND (GP-GM), light brown, very dense

Boring Terminated at 17.5 Feet

4.5

5.5

9.5

13.5

17.5

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

T

G E

O S

M A

R T

L O

G -N

O W

E

LL

C

LO

V

E R

D A

LE

R

D , V

I.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

/1

/2

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

F

IE

LD

T

E S

T R

E S

U

LT

S

R E

C O

V E

R Y

F t.)

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

ATTERBERG

LIMITS

LL-PL-PI

LOCATION See Exploration Plan

Latitude: 43.5806° Longitude: -116.3343°

G R

A P

H

IC

L O

G

DEPTH

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring completed as piezometer.

Notes:

Project No.: 62215009

Drill Rig: CME 75

BORING LOG NO. P-3

Six Mile EngineeringCLIENT:

Boise, ID

Driller: HazTech

Boring Completed: 04-15-2021

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

Elevations not obtained

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

Cloverdale Rd Meridian, ID

SITE:

Boring Started: 04-15-2021

11849 W Executive Dr Ste G Boise, ID

No free water observed while drilling

No free water observed on 4/16/2021

No free water observed on 6/11/2021

WATER LEVEL OBSERVATIONS

S A

M P

LE

T

Y

0.0010.010.1110100

30 40 501.5 2006 810 1441 3/4 1/2 60

GRAIN SIZE IN MILLIMETERS

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

H T

HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

4 3/8 3 100 1403 2

GRAIN SIZE DISTRIBUTION

ASTM D422 / ASTM C136

6 16 20

PROJECT NUMBER: 62215009

SITE: Cloverdale Rd Meridian, ID

PROJECT: Cloverdale Rd, Victory Rd to Overland Rd

CLIENT: Six Mile Engineering Boise, ID

11849 W Executive Dr Ste G Boise, ID

LA

B

O R

A T

O R

Y T

E S

T S

A R

E N

O T

V A

LI

D

IF

S

E P

A R

A T

E D

F R

O M

O R

IG

IN

A L

R E

P O

R T

G R

A

IN

S

IZ

E : U

S C

S -2

C

LO

V

E R

D A

LE

R

D , V

I.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

/1

/2

SILT OR CLAY

I-1

I-2

I-3 mediumcoarse coarsefine fine

COBBLES

GRAVEL SAND

WELL-GRADED SAND with SILT and GRAVEL (SW-SM)

SILTY SAND with GRAVEL (SM)

SILTY SAND with GRAVEL (SM)

1.39 37.678.5 - 10

8 - 9.5

6 - 7.5

3.6

21.7

I-1

I-2

I-3

9.8

15.1

15.3

8.5 - 10

8 - 9.5

6 - 7.5

32.9

36.8

16.7

57.3

48.2

68.0

37.5

2.926

3.456

1.641

0.562

0.342

0.278

0.078

Boring ID Depth WC (%) LL PL PI Cc Cu

%Clay%Fines%Silt%Sand%Gravel Boring ID Depth D100 D60 D30 D10

USCS Classification

%Cobbles 0.0

0.0

0.0

Cloverdale Rd, Victory Rd to Overland Rd Meridian, ID

0.25 to 0.50

> 4.00

2.00 to 4.00

1.00 to 2.00

0.50 to 1.00 less than 0.25

Unconfined Compressive Strength Qu, (tsf)

Standard Penetration Test

N

(HP)

(T)

(DCP)

UC

(PID)

(OVA)

Standard Penetration Test Resistance (Blows/Ft.)

Hand Penetrometer

Torvane

Dynamic Cone Penetrometer

Unconfined Compressive Strength

Photo-Ionization Detector

Organic Vapor Analyzer

SAMPLING WATER LEVEL FIELD TESTS

GENERAL NOTES

DESCRIPTION OF SYMBOLS AND ABBREVIATIONS

Water levels indicated on the soil boring logs are the levels measured in the borehole at the times indicated. Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations.

Water Initially Encountered

Water Level After a Specified Period of Time

Water Level After a Specified Period of Time

Cave In Encountered

Exploration point locations as shown on the Exploration Plan and as noted on the soil boring logs in the form of Latitude and Longitude are approximate. See Exploration and Testing Procedures in the report for the methods used to locate the exploration points for this project. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area.

LOCATION AND ELEVATION NOTES

Soil classification as noted on the soil boring logs is based Unified Soil Classification System. Where sufficient laboratory data exist to classify the soils consistent with ASTM D2487 "Classification of Soils for Engineering Purposes" this procedure is used. ASTM D2488 "Description and Identification of Soils (Visual-Manual Procedure)" is also used to classify the soils, particularly where insufficient laboratory data exist to classify the soils in accordance with ASTM D2487.

In addition to USCS classification, coarse grained soils are classified on the basis of their in-place relative density, and fine-grained soils are classified on the basis of their consistency. See "Strength Terms" table below for details. The ASTM standards noted above are for reference to methodology in general. In some cases, variations to methods are applied as a result of local practice or professional judgment.

DESCRIPTIVE SOIL CLASSIFICATION

The soil boring logs contained within this document are intended for application to the project as described in this document. Use of these soil boring logs for any other purpose may not be appropriate.

RELEVANCE OF SOIL BORING LOG

STRENGTH TERMS

Standard Penetration or N-Value

Blows/Ft.

Descriptive Term (Density)

Hard

15 - 30Very Stiff> 50Very Dense

8 - 15Stiff30 - 50Dense

4 - 8Medium Stiff10 - 29Medium Dense

2 - 4Soft4 - 9Loose

0 - 1Very Soft0 - 3Very Loose

(50% or more passing the No. 200 sieve.)

Consistency determined by laboratory shear strength testing, field visual-manual procedures or standard penetration resistance

> 30

Descriptive Term (Consistency)

Standard Penetration or N-Value

Blows/Ft.

(More than 50% retained on No. 200 sieve.)

Density determined by Standard Penetration Resistance

CONSISTENCY OF FINE-GRAINED SOILSRELATIVE DENSITY OF COARSE-GRAINED SOILS

UNIFIED SOIL CLASSIFICATION SYSTEM

UNIFIED SOI L CLASSI FICATI ON SYSTEM

Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification

Group Symbol Group Name B

Coarse-Grained Soils:

More than 50% retained on No. 200 sieve

Gravels:

More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels:

Less than 5% fines C

Cu ³ 4 and 1 £ Cc £ 3 E GW Well-graded gravel F

Cu < 4 and/or [Cc<1 or Cc>3.0] E GP Poorly graded gravel F

Gravels with Fines:

More than 12% fines C

Fines classify as ML or MH GM Silty gravel F, G, H

Fines classify as CL or CH GC Clayey gravel F, G, H

Sands:

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

Clean Sands:

Less than 5% fines D

Cu ³ 6 and 1 £ Cc £ 3 E SW Well-graded sand I

Cu < 6 and/or [Cc<1 or Cc>3.0] E SP Poorly graded sand I

Sands with Fines:

More than 12% fines D

Fines classify as ML or MH SM Silty sand G, H, I

Fines classify as CL or CH SC Clayey sand G, H, I

Fine-Grained Soils:

50% or more passes the No. 200 sieve

Silts and Clays:

Liquid limit less than 50

Inorganic:

PI > 7 and plots on or above “A” line J

CL Lean clay K, L, M

PI < 4 or plots below “A” line J ML Silt K, L, M

Organic:

Liquid limit - oven dried

< 0.75 OL Organic clay K, L, M, N

Liquid limit - not dried Organic silt K, L, M, O

Silts and Clays:

Liquid limit 50 or more

Inorganic:

PI plots on or above “A” line CH Fat clay K, L, M

PI plots below “A” line MH Elastic Silt K, L, M

Organic:

Liquid limit - oven dried

< 0.75 OH Organic clay K, L, M, P

Liquid limit - not dried Organic silt K, L, M, Q

Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-inch (75-mm) sieve.

B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name.

C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay.

D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay.

E Cu = D60/D10 Cc =

DxD

)(D

F If soil contains ³ 15% sand, add “with sand” to group name.

G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

H If fines are organic, add “with organic fines” to group name.

I If soil contains ³ 15% gravel, add “with gravel” to group name.

J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.

K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant.

L If soil contains ³ 30% plus No. 200 predominantly sand, add

“sandy” to group name.

MIf soil contains ³ 30% plus No. 200, predominantly gravel, add

“gravelly” to group name.

NPI ³ 4 and plots on or above “A” line.

OPI < 4 or plots below “A” line.

P PI plots on or above “A” line.

QPI plots below “A” line.