18. ML 3 Draft Site Characterization Report for Dam_.pdf

DRAFT SITE CHARACTERIZATION

REPORT

MILLER LAKE DAM

BEALE AFB

YUBA COUNTY, CALIFORNIA

PREPARED FOR

DOKKEN ENGINEERING, INC.

FOLSOM, CALIFORNIA

MAY 10, 2017

PROJECT NO. S1307-05-01

Project No. S1307-05-01 May 10, 2017

DRAFT VIA ELECTRONIC MAIL

Richard Liptak, PE Dokken Engineering 110 Blue Ravine Road, Suite 200 Folsom, California 95630

Subject: DRAFT CHARACTERIZATION REPORT

MILLER LAKE DAM

BEALE AIR FORCE BASE

YUBA COUNTY, CALIFORNIA

Dear Mr. Liptak:

In accordance with your authorization, we have prepared this site characterization report for the Miller Lake Dam Lake Dam at Beale Air Force Base (AFB) located east of Yuba City/Marysville in Yuba County, California.

The purpose of this report is to provide a brief characterization of the geologic, seismic, and geotechnical conditions at the site. Analysis, conclusions, and recommendations for the proposed repairs at the site are presented in separate reports.

Please contact us if you have any questions concerning the contents of this report. We look forward to reviewing the project plans as they develop further and providing geotechnical engineering and engineering geology consultation as needed.

Sincerely, GEOCON CONSULTANTS, INC.

Ronald E. Loutzenhiser, PE, GE Jeremy J. Zorne, PE, GE Senior Engineer Senior Engineer

John C. Pfeiffer, PG, CEG Senior Geologist

TABLE OF CONTENTS

DRAFT SITE CHARACTERIZATION REPORT PAGE

EXECUTIVE SUMMARY

1.0 INTRODUCTION

1.1 Scope of Services

1.2 Report Organization

2.0 PROJECT DESCRIPTION

2.1 Background

2.2 Existing Dam

2.3 Proposed Improvements

3.0 LITERATURE REVIEW SUMMARY

4.0 FIELD EXPLORATION PROGRAM SUMMARY

5.0 SOIL AND GEOLOGIC CONDITIONS

5.1 Regional and Local Geology

5.2 Embankment Fill (Qf)

5.3 Alluvium (Qa)

5.4 Mehrten Formation (MPvc)

5.5 Ione Formation (Ei)

5.6 Groundwater/Seepage

6.0 GEOLOGIC HAZARDS AND SEISMICITY

6.1 Mapped Geologic Hazard Zones

6.2 Active Faults

6.3 Standard Response Spectra and Effective Peak Ground Acceleration

6.4 Liquefaction

6.5 Lateral Spreading

6.6 Unsaturated Seismic Settlement

7.0 SUMMARY OF LABORATORY TESTING PROGRAM AND TEST RESULTS

8.0 CLOSURE

TABLE OF CONTENTS (CONTINUED)

FIGURES

Figure 1, Vicinity Map Figure 2, Site Plan Figure 3, Proposed Repair Plan Figure 4, Topographic and Geologic Map Figure 5, Cross-Section A-A’ (Longitudinal) Figure 6, Cross-Section B-B’ (Transverse)

APPENDIX A

FIELD EXPLORATION

Figure A1, Key to Logs Exploratory Boring Logs

APPENDIX B

LABORATORY TESTING PROGRAM

APPENDIX C

HAMMER ENERGY ANALYSIS

Geocon Project No. S1307-05-01 - 1 - May 10, 2017

DRAFT SITE CHARACTERIZATION REPORT

EXECUTIVE SUMMARY

This report presents a brief characterization of the geologic, seismic, and geotechnical conditions at the Miller Lake Dam at Beale Air Force Base (AFB) located east of Yuba City/Marysville in Yuba County, California.

Soil and geologic conditions at the site consist of existing dam embankment fill overlying a minor amount of stream channel alluvium further underlain by formational material consisting of Eocene-age Ione Formation siltstone and sandstone and Tertiary-age Mehrten Formation Conglomerate. Fill materials generally consist of a mixture of sandy and gravelly clay and clayey sands and gravels with variable cobble content. Cobble content of the embankment fill is variable and estimated to be on the order of up to 10 to 20% based on drilling observations. Formational material generally consists of elastic silt, sandy and gravelly clay, clayey gravel, clayey sand, and silty gravel. Cobble content of the formational material is variable and estimated to be on the order of up to 20% based on drilling observations. Preliminary X- Ray diffraction test results indicate the fine-grained (clay) soils are generally composed of kaolinite, with typically minor to moderate expansion potential.

The site is not located in any currently established official geologic hazard zones (e.g. liquefaction, active faulting, landslides) established by the California Geological Survey (CGS) or the local agency specific plan. No active or potentially active faults with the potential for surface fault rupture are known to pass directly beneath the site. Therefore, the potential for surface rupture due to active faulting occurring beneath the site during the design life of the proposed project is considered low.

The site may be subjected to low to moderate ground shaking during an earthquake on regional active faults. The effective Peak Ground Acceleration (PGS) ranges from 0.077g for the Operating Basis Earthquake (OBE) event hazard level (50% probability of exceedance in 100 years or 144-year return period) to 0.152g for the Maximum Design Earthquake (MDE) hazard level (10% probability of exceedance in 100 years or 949-year return period. The site is not subject to significant secondary seismic hazards such as liquefaction, lateral spreading, and unsaturated seismic settlement.

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1.0 INTRODUCTION

This report provides a brief characterization of the geologic, seismic, and geotechnical conditions at the Miller Lake Dam at Beale Air Force Base (AFB) located east of Yuba City/Marysville in Yuba County, California. The approximate site location is shown on the Vicinity Map, in Figure 1. A recent aerial photograph of the site and near vicinity is presented on the Site Plan, Figure 2.

Information contained in this report is based on our field investigation program performed during the period of April 3 through 13, 2017 and subsequent laboratory testing program. Additional pending design-level reports for this project include: 1) Seepage and Stability Analyses Report and 2) Material

Approval Submittal.

1.1 Scope of Services

Our geologic and geotechnical investigation included the following scope of services:

Attended a kickoff meeting at the site on March 31, 2017 with representatives of the designer (Dokken Engineering), Geocon, and the Air Force. The purpose of the meeting was to discuss project specifics and develop a collaborative geotechnical exploration and analysis plan for the project.

Provided information on Geocon and subcontractor personnel using the Entry Access Listing (EAL) procedure for required security background checks.

Performed a limited geologic literature review to aid in evaluating the geologic conditions present at the sites.

Prepared and submitted a Drilling Program Plan (DPP) in general accordance with the guidelines of ER 1110-1-1807. An Activity Hazard Analysis was also prepared as part of the DPP. The DPP was approved on April 4, 2017.

Performed a site reconnaissance to review project limits, determine exploration equipment access and mark out exploratory boring and test pit locations for subsequent utility clearance.

Notified subscribing utility companies via Underground Service Alert (USA) a minimum of two business days (as required by law) prior to performing exploratory borings at the site. Beale AFB personnel reviewed the proposed boring locations and marked out any potential utility or underground structure conflicts.

Retained the services of Gregg Drilling, Inc. a California C57-licensed drilling subcontractor to perform exploratory borings.

Paid required fees and obtained a subsurface exploration permits from the Yuba County Environmental Health Department (YCEHD).

Performed geologic mapping at the site by a California Certified Engineering Geologist (CEG).

Performed 15 exploratory borings (M1 through M15) located in a zig-zag pattern along the crest of the dam. The borings were spaced at approximate 100-foot intervals along the existing dam and were alternately offset towards the upstream and downstream edges of the crown. Boring depths ranged from approximately 3 to 61 feet.

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Obtained representative disturbed and undisturbed soil samples from the exploratory borings consisting of continuous sampling using a sequence of 3-inch outside diameter (OD), 2.5-inch OD, and 2-inch OD (Standard Penetration Test) split spoon samplers per 5 foot sampling interval. Bulk samples were also collected.

Logged the borings in accordance with the Unified Soil Classification System (USCS). Field logging was performed by a California registered Professional Geologist (PG).

Upon completion, backfilled borings with neat cement grout per YCEHD/USACE requirements.

Performed laboratory tests to evaluate pertinent index and engineering parameters.

Prepared this report summarizing the results of our investigation.

1.2 Report Organization

The approximate site location is shown on the Vicinity Map, Figure 1. Current site configuration and approximate locations of exploratory borings are shown on the Site Plan, Figure 2. Proposed repairs are shown on the Proposed Repair Plan, Figure 3. Topography and surficial geology are shown on the Topographic and Geologic Map, Figure 4. A longitudinal geologic cross-section is presented as Cross-Section A-A’, Figure 5. A transverse geologic cross-section is presented as Cross-Section B-B’, Figure 6. Details of our field exploration program including exploratory boring logs are presented in Appendix A. Details of our laboratory testing program and test results are summarized in Appendix B. A copy of the most recent hammer energy analysis for the drill rig used on this project is included as Appendix C.

2.0 PROJECT DESCRIPTION

2.1 Background

The U.S. Army Corps of Engineers (USACE) performed an inspection of Miller Lake Dam in April 2016 and concluded that the dam was in failed to poor condition and recommended corrective actions of existing deficiencies to assure safe operation and performance. USACE performed another inspection in February 2017 and concluded that the dam is threatened due to the severely deteriorated outlet works.

USACE recommended removal and replacement of the low-level intake structure with gate valve and access bridge and outlet works prior to the next wet season.

We understand that the Hazard Potential Classification for the dam is low based on Table B1 in Appendix B of the United States Army Corps of Engineers (USACE) ER 1110-2-1806 (Earthquake

Design and Evaluation for Civil Works Projects).

2.2 Existing Dam

Details of the existing Miller Lake Dam are based on our field observations, limited information available from the Air Force, and review of information prepared by Dokken Engineering. Specific

Geocon Project No. S1307-05-01 - 4 - May 10, 2017 design, construction, or as-built information for the dam is not available as we understand that these documents were destroyed in a structure fire. We understand that as a federal dam located on a Beale AFB, the Miller Lake Dam is under the regulation and authority of the USACE and is not subject to regulation by the California Division of Safety of Dams. For the purposes of this report, “right” and “left” are referenced looking downstream.

Miller Lake Dam is an earth fill dam located on Beale AFB property approximately one-half mile south of Hammonton Smartsville Road and approximately 1½ miles east of Doolittle Drive. The dam is located in gently rolling terrain typical of the western margin of the Sierra Nevada Foothill region. The approximately 1,300-foot-long earth fill dam was constructed in 1962 across a seasonal creek and ranges in height up to 24 feet. The crest is approximately 27 feet wide and is situated at an elevation of approximately 194 feet referenced to the North American Vertical Datum of 1988 (NAVD 88). The slope inclination of the upstream dam face varies from approximately 1.5H:1V (horizontal:vertical) in the upper portion to 3H:1V in the lower portion of the slope. The slope inclination of the downstream dam face is approximately 1.9H:1V. Rock slope protection is generally present on the upstream and downstream faces of the dam.

When full to the spillway crest (elevation 189.5 feet NAVD 88), the dam impounds approximately 580 acre-feet of water. The dam includes three spillways and an outlet works structure. The primary spillway is a three-cell reinforced concrete box culvert in the left abutment with the invert approximately 4½ feet below the dam crest. The secondary spillway is a three-foot diameter corrugated metal pipe (CMP) in the right abutment. A supplementary spillway was added after dam overtopping events in the 1990’s and consists of a 75-foot long concrete weir structure about 2½ feet below the dam crest near the left abutment.

The reinforced concrete outlet works is located near the center of the dam and consists of a control tower in the lake and associated 18-inch diameter reinforced concrete pipe (RCP) extending under/through the dam.

Features of the Miller Lake Dam are shown on the Site Plan, Figure 2. Topography based on a recent survey by UNICO Engineering is shown on the Topographic and Geologic Map, Figure 4. The dam cross-section geometry (longitudinal and transverse) is shown on Figures 5 and 6.

2.3 Proposed Improvements

As demonstrated by recent overtopping events, the hydraulic capacity of the existing spillways and outlet works is insufficient for the design flows and the outlet works is currently non-functional (clogged) and is experiencing seepage and potential internal erosion around the structure. We understand that the proposed improvements include replacement of the main and secondary spillways as well as the outlet works. The main and secondary spillways will be replaced with multi-cell, precast box culverts. Modifications to the supplementary spillway are not proposed at this time. The outlet works is to be replaced. The proposed improvements may be constructed in one or two construction seasons. The proposed improvements are shown on the Proposed Repair Plan, Figure 3.

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3.0 LITERATURE REVIEW SUMMARY

Specific design, construction, or as-built information for the dam is not available as we understand that these documents were destroyed in a structure fire. Therefore, our literature review was limited to published geologic literature, regulatory design guidance documents, and related information.

Following is a list of references:

1. Air Force Design Guides/Standards, Air Force Engineering Technical Letters, Air Force

Handbooks, Air Force Instructions, Policies and Guidance for Air Force Design and Construction, Air Force Regulations.

2. California Department of Transportation, Standard Plans, 2015.

3. Federal Emergency Management Agency (FEMA) Technical Manual (FEMA 484), Conduits through Embankment Dams.

4. Saucedo, G.J., and Wagner, D.L., Geologic Map of the Chico Quadrangle, California, California Geological Survey, Regional Geologic Map Series, Map No. 7A, scale 1:250,000, 1992.

5. Unpublished reports, aerial photographs, and maps on file with Geocon.

6. USACE EM 1110-1-1804, Engineering and Design, Geotechnical Investigations.

7. USACE EM 1110-2-1901, Engineering and Design, Seepage Analysis and Control for Dams.

8. USACE EM 1110-2-1902, Engineering and Design, Slope Stability.

9. USACE EM 1110-2-1906, Engineering and Design, Laboratory Soils Testing.

10. USACE EM 1110-2-1911, Engineering and Design, Construction Control for Earth and Rock-Fill Dams.

11. USACE EM 1110-2-1913, Engineering and Design, Design and Construction of Levees.

12. USACE EM 1110-2-2300, Engineering and Design, General Design and Construction Considerations for Earth and Rock-Fill Dams.

13. USACE EM 1110-2-2902, Engineering and Design, Conduits, Culverts, and Pipes.

14. USACE ER 1110-1-1807, Engineering and Design, Drilling in Earth Embankment Dams and Levees.

15. USACE ER 1110-2-1806, Engineering and Design, Earthquake Design and Evaluation for Civil Works Projects.

16. USACE, Miller Lake Dam, NID CA 10119, Beale Air Force Base, California, Periodic Inspection, April 2016.

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4.0 FIELD EXPLORATION PROGRAM SUMMARY

Our field investigation program was performed during the period of April 3 through 13, 2017 and consisted of drilling 15 exploratory borings (M1 through M15) at the approximate locations shown on the Site Plan, Figure 2 and Topographic and Geologic Map, Figure 4.

Table 4.0 summarizes the details of our exploratory borings. Location information (latitude, longitude, and elevation) was provided by the project surveyor, UNICO Engineering, Inc. (UNICO). Elevations are based on NAVD 88 as adjusted to National Geodetic Survey Permanent Identifier (NGS PID) KS0774 with an elevation of 93.73 feet. Latitude and longitude are based on the North American Datum of 1983 (NAD83) California Zone 2 Epoch 2010.00 as adjusted to NGS PID DL9191, KS0774, and DL 9143.

TABLE 4.0

SUMMARY OF EXPLORATORY BORINGS – MILLER LAKE DAM

Exploratory borings were performed using a truck-mounted Marl M-10 drill rig equipped with 8-inch outside diameter (OD) hollow stem augers. Soil samples were collected continuously using a sequence of 3-inch outside diameter (OD), 2.5-inch OD, and 2-inch OD Standard Penetration Test (SPT) split spoon samplers per 5-foot boring interval to the total depths explored. Sampling was accomplished using a 140-pound, automatic hammer with a 30-inch drop. The automatic hammer has an overall energy transfer ratio (ETR) of 76% per the most recent energy analysis for this hammer (Appendix C).

The 3-inch OD and 2.5-inch OD samplers were equipped with 6-inch-long brass sample tubes to facilitate sample removal and laboratory testing. The SPT sampler had a uniform inside diameter that did not allow for sample liners. The number of blows required to drive the samplers (blow counts) the last 12 inches of the 18-inch sample drive (or portion thereof) are reported on the boring logs.

Boring ID Approximate Boring Location

Boring Depth (feet) Latitude

(degrees North) Longitude

(degrees West) Elevation

(feet NAVD 88) M1 39.10109884 -121.2411612 198.4 39.5 M2 39.10102317 -121.2411109 194.3 39.5 M3 39.10093558 -121.2410278 193.5 39.5 M4 39.10085597 -121.240947 193.8 39.9 M5 39.10077164 -121.2408936 194.1 61.4 M6 39.10068314 -121.2408013 194.0 38.9 M7 39.10060326 -121.2407542 193.7 38.8 M8 39.10051801 -121.2406601 192.9 37.0 M9 39.10041495 -121.240593 193.6 32.5

M10 39.10032017 -121.2404935 193.0 25.5 M11 39.10022287 -121.2404127 193.5 15.5 M12 39.09598146 -121.2402389 193.7 9.0 M13 39.09593902 -121.2401791 194.7 3.0 M14 39.10072285 -121.2408501 194.0 45.2 M15 39.10081591 -121.2409279 193.7 49.5

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The blow counts presented on the logs are raw, uncorrected values. The borings were logged by a California registered Professional Geologist (PG). Upon completion, the borings were backfilled borings with neat cement grout per YCEHD/USACE requirements. Draft exploratory borings logs are presented in Appendix A.

5.0 SOIL AND GEOLOGIC CONDITIONS

Soil and geologic conditions at the site consist of existing dam embankment fill overlying a minor amount of stream channel alluvium further underlain by formational material consisting of Eocene-age Ione Formation claystone and Tertiary-age Mehrten Formation Conglomerate. Surface geology at site is presented on the Topographic and Geologic Map, Figure 4. Geologic cross-sections (longitudinal and transverse to the dam) are presented as Cross-Sections A-A’ and B-B’, Figures 5 and 6, respectively. Soil descriptions provided below include the Unified Soil Classification System (USCS) symbol where applicable. Table 5 summarizes the approximate thickness of the dam embankment/elevation of formational material contact encountered in our borings.

TABLE 5

DAM EMBANKMENT THICKNESS

5.1 Regional and Local Geology

The site is near the approximate margin of the Great Valley and Sierra Nevada geomorphic provinces.

The Great Valley (Sacramento and San Joaquin Valleys) of California is a long, sediment-filled structural depression or down-warped trough, with the axis of the trough beneath the west side of the valley. In general, the southern portion of the Sacramento Valley is underlain by Quaternary continental deposits (alluvial deposits) and late Tertiary age marine and continental sedimentary rocks.

The Sierra Nevada is a tilted fault block nearly 400 miles long with a high, rugged, multiple-scarp east

Boring ID Boring Elevation

(feet MSL)

Approximate Dam Embankment Thickness

(feet)

Approximate Formational Material Elevation

(feet MSL) M1 198.4 2 196.4 M2 194.3 10 184.3 M3 193.5 17.5 176.0 M4 193.8 35 158.8 M5 194.1 36 158.1 M6 194.0 32.5 161.5 M7 193.7 32.5 161.3 M8 192.9 26.5 166.4 M9 193.6 21 172.6

M10 193.0 19.8 173.2 M11 193.5 11 182.5 M12 193.7 0.5 193.2 M13 194.7 0 194.7 M14 194.0 30 164.0 M15 193.7 31.5 162.2

Geocon Project No. S1307-05-01 - 8 - May 10, 2017 face contrasting with the gentle western slope that disappears under the sediments of the Great Valley.

The site is in a region where both the Sierran bedrock and overlying Great Valley sedimentary deposits are exposed.

Regional geologic mapping (California Geological Survey [CGS], 1992) depicts the site underlain by sedimentary materials of the Eocene-age Ione Formation (Ei). Based on our subsurface investigation and geologic reconnaissance, the site is underlain predominantly by Ione Formation materials and volcanic cobble conglomerate of the Tertiary-age Mehrten Formation (MPvc). We also encountered Quaternary-age alluvium (Qa) underlying the dam at the axis of the drainage. The general geologic setting of the site is depicted on Figure 4.

5.2 Embankment Fill (Qf)

Miller Lake Dam is constructed of fill material (see Figure 2) presumably derived from nearby excavations. The fill material is predominantly clayey gravel with sand (GC), clayey sand with gravel (SC), and lean clay (CL) with gravel, all with varying cobble content. It appears to be derived from the adjacent deposits of Mehrten Formation and Ione Formation sediments. Based on our investigation, the dam does not appear to contain different material zones or drainage zones.

5.3 Alluvium (Qa)

Alluvium at the site is unconsolidated sediment deposited by the creek that was impounded by Miller Lake Dam. It consists predominantly of silty clay with sand and silty sand with gravel. We encountered approximately 5 feet of alluvium underlying the embankment fill material in one boring (Boring M4), where it was underlain by completely weathered siltstone of the Ione Formation. We also observed alluvium in the active drainage downstream from the dam, where it overlies Mehrten and Ione Formation materials (Figures 4 and 5).

5.4 Mehrten Formation (MPvc)

At the site, the Tertiary-age Mehrten Formation deposits are a volcanic cobble conglomerate consisting of moderately cemented, rounded andesitic cobble in a reddish-yellow sandstone/siltstone (sandy/clayey) matrix. The cobble conglomerate contained rounded to subrounded gravel and cobble, with trace boulders up to approximately 2 feet in maximum dimension. We generally encountered auger refusal on the Mehrten Formation materials after drilling approximately 3 to 10 feet into the cobble conglomerate using a Marl M-10 drill rig equipped with 8-inch-diameter hollow-stem augers. However, we drilled 15 feet into the conglomerate in one boring (M14) before encountering auger refusal. In Boring M15, we drilled 10 feet through the Mehrten Formation conglomerate and encountered the underlying Ione Formation siltstone.

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5.5 Ione Formation (Ei)

Ione Formation deposits at the site consist primarily of white to yellowish-brown or yellowish-gray, highly weathered siltstone and sandstone. The Ione Formation materials excavate variously as weak, blocky elastic silt (MH) with gravel and sand, lean clay (CL), or silty/sandy clay (CL), or silty clayey sand (SC). At the location of Boring M5, the Ione Formation sandstone was loose to medium dense immediately below the Mehrten Formation.

5.6 Groundwater/Seepage

At the time of our investigation, April 3 through 13, 2017, the water surface elevation in Miller Lake ranged from approximately 170.9 feet to 172.5 feet. We encountered groundwater in our borings at various depths during drilling as summarized in Table 5.6.

TABLE 5.6

GROUNDWATER SUMMARY

Note: 1. Groundwater depth at the time of drilling, measured to the nearest ½-foot.

Based on the conditions observed in our exploratory borings, it appears that the impounded water in the lake seeps through the dam cross-section. At a minimum, groundwater/seepage should be anticipated during excavation into the lower portion of the dam cross-section particularly during and following the period when the dam is impounding water. Given that the proposed repairs will require excavation and construction at the lowest portion of the dam, dewatering will likely be necessary.

Boring ID Date Boring Depth

(feet)

Approximate Groundwater Depth1

(feet)

Approximate Groundwater Elevation

(feet MSL) M1 April 6-7, 2017 39.5 -- -- M2 April 10, 2017 39.5 -- -- M3 April 10-11, 2017 39.5 -- -- M4 April 3, 2017 39.9 28 165.8 M5 April 3-4, 2017 61.4 33 161.1 M6 April 4, 2017 38.9 28½ 165.5 M7 April 5, 2017 38.8 32½ 161.3 M8 April 5, 2017 37.0 -- -- M9 April 11, 2017 32.5 27 166.6

M10 April 11, 2017 25.5 -- -- M11 April 12, 2017 15.5 -- -- M12 April 6, 2017 9.0 -- -- M13 April 6, 2017 3.0 -- -- M14 April 13, 2017 45.2 27 167.0 M15 April 13, 2017 49.5 27 166.7

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It should be noted that fluctuations in the level of groundwater may occur due to variations in rainfall, temperature, and other factors. Depth to groundwater can also vary significantly due to localized pumping, irrigation practices, and seasonal fluctuations. Therefore, it is possible that groundwater may be encountered during construction.

6.0 GEOLOGIC HAZARDS AND SEISMICITY

6.1 Mapped Geologic Hazard Zones

The site is not located in any currently established official geologic hazard zones (e.g. liquefaction, active faulting, landslides) established by the California Geological Survey (CGS) or the local agency specific plan.

6.2 Active Faults

The numerous faults in Northern California include active, potentially active, and inactive faults.

The criteria for these major groups are based on criteria developed by the California Division of Mines and Geology (CDMG, now CGS) for the Alquist-Priolo Earthquake Fault Zone (APEFZ) Program (Hart, 1999). By definition, an active fault is one that has had surface displacement within the last 11,000 years. A potentially active fault has demonstrated surface displacement during Quaternary time (approximately the last 1.6 million years) but has had no known movement within the past 11,000 years. Faults that have not moved in the last 1.6 million years are considered inactive.

The site is not located within a currently established APEFZ. Based on our reconnaissance, evidence obtained in exploratory borings, and our review of geologic maps and reports, no active or potentially active faults with the potential for surface fault rupture are known to pass directly beneath the site.

Therefore, the potential for surface rupture due to active faulting occurring beneath the site during the design life of the proposed project is considered low. The site, however, is located in a seismically active area and could be subjected to ground shaking in the event of an earthquake on one of the many active Northern California faults.

In order to evaluate the distance of known active faults within 60 miles of the site, we reviewed local and regional geologic maps and used the computer program EQFAULT, (Version 3, Blake, 2000).

Principal references used within EQFAULT are Jennings (1975), Anderson (1984) and Wesnousky (1986). Results are summarized in Table 6.2.

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TABLE 6.2

REGIONAL ACTIVE FAULTS

Fault Name Distance from Site (miles)

Maximum Moment Magnitude (MW)

Foothills Fault System 1.4 6.5 Great Valley 3 44.1 6.8 Great Valley 2 47.6 6.4 Great Valley 1 48.0 6.7 Great Valley 4 50.0 6.6 Mohawk – Honey Lake Zone 53.7 7.3

6.3 Standard Response Spectra and Effective Peak Ground Acceleration

Ground shaking refers to propagation of seismic waves to the ground surface as a result of an earthquake. The intensity of ground shaking is a function of the earthquake’s magnitude, distance from the epicenter, depth below the surface, and subsurface conditions. Areas underlain with unconsolidated, saturated sediments are more prone to significant ground shaking than areas underlain by bedrock.

Seismic ground shaking hazards are commonly characterized through the horizontal Peak Ground Acceleration (PGA) or the Modified Mercalli Index (MMI) scale associated with a scenario or characteristic earthquake event. PGA is expressed in terms of the acceleration (g) due to the earth’s gravity.

We evaluated the standard response spectra and effective PGA in accordance with the procedures presented in the EM 1110-2-6053 (May 2007). The analyses were performed for the Operating Basis Earthquake (OBE) hazard level which is defined as the level of ground motion with a 50% probability of exceedance in 100 years (return period of 144 years) at 5% damping. The analyses were also performed for the Maximum Design Earthquake (MDE) hazard level which is defined as the level of ground motion with a 10% probability of exceedance in 100 years (return period of 949 years) at 5 percent damping. The definition of the MDE hazard level was defined based on the consideration of the “low” hazard potential classification evaluated per ER 1110-2-1806 Table B-1 (May 2016).

The effective PGA was evaluated as the ratio of the spectral acceleration at 0.2 seconds and a constant value of 2.5, as recommended by EM 1110-2-6053. Results are summarized in Table 6.3.

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TABLE 6.3a

PEAK GROUND ACCELERATION (PGA)

OBE1 MDE2

0.077g 0.153g Notes:

1. OBE = Operating Basis Earthquake (50% probability of exceedance in 100 years, 144-year return period)

2. MDE = Maximum Design Earthquake (10% probability of exceedance in 100 years, 949-year return period)

The evaluation of the standard response spectra for the OBE and MDE hazard levels was based on the USGS National Hazard Mapping Project 2008 NEHRP maps. The 2008 NEHRP maps present uniform hazard, probabilistic geometric mean spectral accelerations. The spectral accelerations at peak ground acceleration, 0.2 seconds, and 1.0 seconds were evaluated using the USGS online BETA Unified Hazard Tool, 2008 Conterminous U.S. 2008 (v3.2.x) edition. The spectral accelerations were taken at a Site Class B (shear wave velocity of 760 meters per second) for hazard levels of 2 percent in 50 years (return period of 2,475 years) and 10 percent in 50 years (return period of 475 years). The values were adjusted to the OBE and MDE hazard levels and then further adjusted for site class following the procedures outlined in EM 1110-2-6053. Based on the conditions encountered in our borings, the soil underlying the site was modeled as Site Class “C”. Standard horizontal response spectra for the OBE and MDE hazard levels were constructed following the definitions of EM 1110-2-6053 and are presented in Table 6.3b.

TABLE 6.3b

RESPONSE SPECTRA

Period (sec) OBE1 MDE2

PGA 0.077g 0.153g

0.1 0.171g 0.352g

0.2 0.192g 0.379g

0.3 0.192g 0.379g

0.5 0.192g 0.379g 1 0.117g 0.216g 2 0.06g 0.11g

Notes:

1. OBE = Operating Basis Earthquake (50% probability of exceedance in 100 years, 144-year return period)

2. MDE = Maximum Design Earthquake (10% probability of exceedance in 100 years, 949-year return period)

6.4 Liquefaction

Liquefaction is a phenomenon in which saturated cohesionless soils are subject to a temporary loss of shear strength due to pore pressure buildup under the cyclic shear stresses associated with intense earthquakes. Primary factors that trigger liquefaction are: moderate to strong ground shaking (seismic source), relatively clean, loose granular soils (primarily poorly graded sands and silty sands), and

Geocon Project No. S1307-05-01 - 13 - May 10, 2017 saturated soil conditions (shallow groundwater). Due to the increasing overburden pressure with depth, liquefaction of granular soils is generally limited to the upper 50 feet of a soil profile. Based on the subsurface conditions at the site, we do not consider liquefaction to be a hazard for the site.

6.5 Lateral Spreading

Based on the lack of significant liquefaction potential at the site, we do not consider lateral spreading to be a hazard for the site.

6.6 Unsaturated Seismic Settlement

Strong seismic shaking can induce settlement of unsaturated, loose sandy soil. Based on the subsurface conditions at the site, we do not consider unsaturated seismic settlement to be a significant hazard for the site.

7.0 SUMMARY OF LABORATORY TESTING PROGRAM AND TEST RESULTS

Our laboratory testing program generally focused on evaluating the index and engineering properties of the dam embankment material and underlying foundation materials per the general recommendations of EM 1110-1-1804 and EM 1110-2-1906. Our in-house laboratory is accredited by the USACE. We performed the following laboratory tests:

Visual sample classification;

In-situ Moisture/Density, American Society for Testing and Materials (ASTM) D2216 or D4643;

Grain Size Distribution, ASTM D1140 and D422;

Hydrometer Analysis, ASTM D422;

Atterberg Limits, ASTM D4318;

X-Ray Diffraction Analysis (XRD);

Organic Content, ASTM D2974;

Maximum Dry Density/Optimum Moisture Content, ASTM D698;

Double Hydrometer, ASTM D4221, or Pinhole Test, ASTM D4647;

Permeability, Flexible-Wall, ASTM D5084 (Intact/Remolded Samples);

Unconfined Compressive Strength, ASTM D2166;

Consolidated-Undrained Triaxial 3-Point, ASTM D4767 (Intact/Remolded Samples);

Unconsolidated-Undrained Triaxial Staged, ASTM D2850 (Intact/Remolded Samples);

pH and Resistivity, CTM 643;

Sulfate Content, CTM 417; and Chloride Content, CTM 422.

Geocon Project No. S1307-05-01 - 14 - May 10, 2017

Laboratory test results are presented in Appendix B. Laboratory testing is still underway at the time of this draft report; complete laboratory test results will be included in the final report for this project.

8.0 CLOSURE

This report is intended to provide a brief characterization of the geologic, seismic, and geotechnical conditions at the site. Analysis, conclusions, and recommendations for the proposed repairs at the site are presented in separate reports.

Conditions at the site can change with the passage of time, whether due to natural processes or the works of man on this or adjacent sites. Additionally, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated partially or wholly by changes outside our control.

Therefore, this report is subject to review and should not be relied upon after a period of three years.

Our professional services were performed, our findings obtained, and our recommendations prepared in accordance with generally accepted geotechnical engineering principles and practices used in this area at this time. No warranty is provided, express or implied.

Gavin Mandry

B

Smartville

Hammonton-

R d.

Simpson

McGowan Pkwy.

Marysville

Olivehurst

Beale

AFB

Beale AFB Aero Club

Yuba County Airport

Gavin Mandry Dr.

Dr.

Doolittle

Rd.

Rd

Be ale

Rd.

Rd.

St

B

La ug hl in

Smartville

Hammonton-

Beale

Erie

Rd.

Bl vd

R d.

Ar bo ga

R iv er Fe at he r

Ln.

Simpson

Erie

McGowan Pkwy.

70 65

Marysville

Olivehurst

Beale

AFB

Beale AFB Aero Club

Yuba County Airport

Fe at he r

Ri ve r

River

Yu ba

R d.Miller

Lake Dam Miller

Lake Dam

N 0 2

Scale in Miles

Miller Lake Dam Yuba County, California

VICINITY MAP

May 2017 Figure 1S1307-05-01

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 2

3 1 6 0 G O L D VA L L E Y D R – S U I T E 8 0 0 – R A N C H O C O R D O VA , C A 9 5 7 4 2

Miller Lake Dam Yuba County, California

SITE PLAN

May 2017 Figure 2S1307-05-01

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 2

3 1 6 0 G O L D VA L L E Y D R – S U I T E 8 0 0 – R A N C H O C O R D O VA , C A 9 5 7 4 2

M1

M2

M3 M4

M15 M14 M6

M7

M8

M9

M10 M11

M12 M13M5

M1

M2

M3 M4

M15 M14 M6

M7

M8

M9

M10 M11

M12 M13M5

0 100

Approx. Scale in Feet

MILLER

LAKE

Miller Lake Dam

Spillway

Graded Rock Channel Outlet

Graded Rock Channel Outlet

MILLER

LAKE

LEGEND:

Approximate Boring Location

Approximate Extents of Fill

B1

Miller Lake Dam

Spillway

Graded Rock Channel Outlet

Graded Rock Channel Outlet

California

PROPOSED REPAIR PLAN

May 2017 Figure 3S1307-05-01

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 2

N

California

TOPOGRAPHIC AND GEOLOGIC MAP

May 2017 Figure 4S1307-05-01

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 2

3 1 6 0 G O L D VA L L E Y D R – S U I T E 8 0 0 – R A N C H O C O R D O VA , C A 9 5 7 4 2

LEGEND:

Approximate Boring Location (Geocon 2017)

Approximate Cross-Section Locations (Figures 5 and 6)

M1

M1 M2

M3

M4

M15 M5 M14

M6

M7

M8

M9

M10 M11 M12

M13

MILLER

LAKE

M1 M2

M3

M4

M15 M5 M14

M6

M7

M8

M9

M10 M11 M12

M13

A A'

A'A'

0 100

Scale in Feet

N

36" CMP

Culvert

18" RCP

Culvert

Box Culvert

Concrete

36" CMP

Culvert

18" RCP

Culvert

Box Culvert

Concrete

MILLER

LAKE

Water Level ~ 171' on 5/4/17

Water Level ~ 171' on 5/4/17

Qa MPvc

Qfe

Qfe

Qfe

MPvc

MPvc

MPvc

MPvc

Ei

Ei Qa

MPvc

Qfe

Qfe

Qfe

MPvc

MPvc

MPvc

MPvc

Ei

Ei

B B

B

B

AA

EMBANKMENT FILL

ALLUVIUM

MEHRTEN FORMATION

IONE FORMATION

QfeQfe

Qa

MPvc

Ei

Qa

MPvc

Ei

California

CROSS-SECTION A – A' (LONGITUDINAL)

May 2017 Figure 5S1307-05-01

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 2

3 1 6 0 G O L D VA L L E Y D R – S U I T E 8 0 0 – R A N C H O C O R D O VA , C A 9 5 7 4 2

A A' Northwest Southeast

0 100

Horizontal Scale in Feet

Ve rt ic al

Sc al e in

F ee t

LEGEND:

Boring Location

Total Depth (Ft.)

Geologic Contact

M

Lithologic Contact

TD=

El ev at io n in

F ee t ( M

SL

El ev at io n in

F ee t ( M

SL

IONE FORMATION

Hard Silt/Clay and Very Dense Sand and Gravel

IONE FORMATION

Hard Silt/Clay and Very Dense Sand and Gravel

MEHRTEN FORMATION

Cobble Conglomerate

MEHRTEN FORMATION

Cobble Conglomerate

M

TD=39.5'

TD=39.5' TD=39.5' TD=39.9'

TD=39.5'

M

TD=39.5'

M

TD=39.5'

M

TD=39.9'

TD=49.5'

TD=38.9'

TD=61.4'

M

TD=49.5'

M

M

TD=38.9'

M

TD=61.4'

TD=38.8'

TD=37.0'

TD=32.5'

TD=25.5'

TD=15.5'

M

TD=38.8'

M

TD=37.0'

M

TD=32.5'

M

TD=25.5'

M

TD=15.5'

TD=9.0'

TD=3.0'

M

TD=9.0'

M

TD=3.0'

Dam Road Concrete Spillway

Box Culvert

ALLUVIUM

Soft Clay and Dense Sand

ALLUVIUM

Soft Clay and Dense Sand

Note: 10X Vertical Exaggeration

EMBANKMENT FILL

ALLUVIUM

MEHRTEN FORMATION

IONE FORMATION

QfeQfe

Qa

MPvc

Ei

Qa

MPvc

Ei

TD=45.2'TD=45.2'

??Loose to Medium Dense Clayey Sand

Loose to Medium Dense Clayey Sand

36" CMP

Culvert

36" CMP

Culvert DAM EMBANKMENT

Stiff Clay with Sand, Gravel, and

Cobbles

DAM EMBANKMENT

Stiff Clay with Sand, Gravel, and

Cobbles

DAM EMBANKMENT

Stiff Clay with Sand, Gravel, and

Cobbles

DAM EMBANKMENT

Stiff Clay with Sand, Gravel, and

Cobbles

18" RCP

Culvert

18" RCP

Culvert

California

CROSS-SECTION B – B' (TRANSVERSE)

May 2017 Figure 6S1307-05-01

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 2

3 1 6 0 G O L D VA L L E Y D R – S U I T E 8 0 0 – R A N C H O C O R D O VA , C A 9 5 7 4 2

B Southwest

B' Northeast

0 20

Horizontal Scale in Feet

Ve rt ic al

Sc al e in

F ee t

LEGEND:

Boring Location

Total Depth (Ft.)

Geologic Contact

M

Groundwater

TD=

El ev at io n in

F ee t ( M

SL

El ev at io n in

F ee t ( M

SL

Note: 2X Vertical Exaggeration

M

1.9H:1V

1.5H:1V

3.0H:1V

20H:1V

MILLER LAKE

7.5H:1V

5H:1VOutlet Pipe

Outlet Structure

EMBANKMENT FILL

MEHRTEN FORMATION

QfeQfe

MPvcMPvc

EMBANKMENT FILL

MEHRTEN FORMATION MEHRTEN FORMATION

54/11"

67/10"

4/4/17 19

93/10" 88/11"

TD=38.9'

Assumed Outlet Pipe Alignment

EMBANKMENT FILL

MEHRTEN FORMATION MEHRTEN FORMATION

54/11"

67/10"

4/4/17 19

93/10" 88/11"

TD=38.9'

Assumed Outlet Pipe Alignment

APPENDIX A

APPENDIX A

FIELD EXPLORATION

Our field investigation program was performed during the period of April 3 through 13, 2017 and consisted of drilling 15 exploratory borings (M1 through M15) at the approximate locations shown on the Site Plan, Figure 2 and Topographic and Geologic Map, Figure 4.

Table A summarizes the details of our exploratory borings. Location information (latitude, longitude, and elevation) was provided by the project surveyor, UNICO Engineering, Inc. (UNICO). Elevations are based on the North American Vertical Datum of 1988 (NAVD 88) as adjusted to National Geodetic Survey Permanent Identifier (NGS PID) KS0774 with an elevation of 93.73 feet. Latitude and longitude are based on the North American Datum of 1983 (NAD83) California Zone 2 Epoch

2010.00 as adjusted to NGS PID DL9191, KS0774, and DL 9143.

TABLE A1

SUMMARY OF EXPLORATORY BORINGS – MILLER LAKE DAM

Exploratory borings were performed using a truck-mounted Marl M-10 drill rig equipped with 8-inch outside diameter (OD) hollow stem augers. Soil samples were collected continuously using a sequence of 3-inch outside diameter (OD), 2.5-inch OD, and 2-inch OD Standard Penetration Test (SPT) split spoon samplers per 5-foot boring interval to the total depths explored. Sampling was accomplished using a 140-pound, automatic hammer with a 30-inch drop. The automatic hammer has an overall energy transfer ratio (ETR) of 76% per the most recent energy analysis for this hammer (Appendix C). The 3-inch OD and 2.5-inch OD samplers were equipped with 6-inch-long brass sample tubes to facilitate sample removal and laboratory testing. The SPT sampler had a uniform inside diameter that did not allow for sample liners. The number of blows required to drive the

Boring ID Approximate Boring Location

Boring Depth (feet) Latitude

(degrees North) Longitude

(degrees West) Elevation

(feet MSL) M1 39.10109884 -121.2411612 198.4 39.5 M2 39.10102317 -121.2411109 194.3 39.5 M3 39.10093558 -121.2410278 193.5 39.5 M4 39.10085597 -121.240947 193.8 39.9 M5 39.10077164 -121.2408936 194.1 61.4 M6 39.10068314 -121.2408013 194.0 38.9 M7 39.10060326 -121.2407542 193.7 38.8 M8 39.10051801 -121.2406601 192.9 37.0 M9 39.10041495 -121.240593 193.6 32.5

M10 39.10032017 -121.2404935 193.0 25.5 M11 39.10022287 -121.2404127 193.5 15.5 M12 39.09598146 -121.2402389 193.7 9.0 M13 39.09593902 -121.2401791 194.7 3.0 M14 39.10072285 -121.2408501 194.0 45.2 M15 39.10081591 -121.2409279 193.7 49.5 samplers (blow counts) the last 12 inches of the 18-inch sample drive (or portion thereof) are reported on the boring logs. The blow counts presented on the logs are raw, uncorrected values.

The borings were logged by a California registered Professional Geologist (PG). Upon completion, the borings were backfilled borings with neat cement grout per YCEHD/USACE requirements. Draft exploratory borings logs are presented in Appendix A.

COMPACTION CURVE (ASTM D1557)

CORROSION ANALYSIS (CTM 422, 643, 417)

DIRECT SHEAR (ASTM D3080)

EXPANSION INDEX (ASTM D4829)

GRAIN SIZE ANALYSIS (ASTM D422)

MOISTURE CONTENT (ASTM D2216)

PLASTICITY INDEX (ASTM D4318)

LABORATORY TEST KEY

CP –

CR –

DS –

EI –

GSA –

MC –

PI –

R-VALUE (CTM 301)

SAND EQUIVALENT (CTM 217)

CONSOLIDATED UNDRAINED

TRIAXIAL (ASTM D4767)

UNCONSOLIDATED UNDRAINED

TRIAXIAL (ASTM D2850)

R –

SE –

TXCU –

TXUU –

UNCONFINED COMPRESSIVE

STRENGTH (ASTM D2166)

UC –

3" O.D.

2" O.D., 1.4" I.D.

3" O.D., 2.4" I.D.

KEY TO LOGS Figure A1

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 2

M1-0.5

M1-1.0

M1-Bulk

M1-2.0

M1-3.0

M1-5.5

M1-6.0

M1-6.5

M1-7.0

M1-7.5

M1-8-9.5

M1-10.5

M1-11.0

M1-11.5

M1-12.0

M1-13.0

NR

M1-17.0

M1-17.5

M1-18-19.5

M1-20.0

M1-20.5

M1-21.0

M1-21.5

M1-22.0

M1-22.5

M1-23.0

68/11"

80/10"

85/9"

50/6"

50/3"

84/10"

65/11"

DAM EMBANKMENT

Hard, moist, light yellowish brown, Elastic SILT

IONE FORMATION

Highly weathered SILTSTONE, weak Excavates as: Hard, moist, light yellowish brown, Elastic SILT with sand, moderately cemented

- becomes highly cemented

- becomes very stiff

- becomes hard, yellowish gray, less cemented

- with white layer

Hard, moist, yellowish gray, Elastic SILT with gravel and sand

- with weathered rock

- becomes very stiff

- becomes hard

- with whitish gray, orange and white

88.3

78.3

98.0

99.7

99.7

109.6

MH

MH

MH

6.3

9.6

31.9

30.2

21.6

21.1

14.3

24.2

17.3

L

IT

H O

L O

G Y

ENG./GEO.

HAMMER TYPEEQUIPMENT

MATERIAL DESCRIPTION

(B L

O W

S /F

T

R E

S

IS

T A

N C

E

SOIL

SAMPLE

DEPTH

NO.

P E

N E

T R

A T

IO

N

IN

D R

Y D

E N

S

IT

Y

Log of Boring, page 1 of 2

ELEV. (MSL.) DATE COMPLETED 4/7/2017

GEOTECH SAMPLER 3 S1307-05-01 MILLER LAKE DAM.GPJ 05/09/17

SAMPLE SYMBOLS

... SAMPLING UNSUCCESSFUL

(P .C

.F

G R

O U

N D

W A

T E

R

... DISTURBED OR BAG SAMPLE

BORING M1

Automatic Marl M-10 Drill Rig with

8" HSA

DRILLER

C O

N T

E N

T

... STANDARD PENETRATION TEST

... DRIVE SAMPLE (2.0 INCH I.D.)

M O

IS

T

U R

E

Gregg Drilling

FEET (USCS)

Sean Dixon

... WATER TABLE OR SEEPAGE

CLASS

... DRIVE SAMPLE (2.4 INCH I.D.)

NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF

SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.

PROJECT NO. S1307-05-01 PROJECT NAME Miller Lake Dam - Beale AFB

Boeschen C Typewritten Text

Boeschen C Typewritten Text

Boeschen C Typewritten Text

Boeschen C Typewritten Text

Boeschen C Typewritten Text

M1-25.0

M1-25.5

M1-26.0

M1-26.5

M1-27.0

M1-27.5

M1-28.0

M1-30.0

M1-30.5

M1-31.0

M1-31.5

M1-32.0

M1-32.5

M1-33.0

M1-35.0

M1-35.5

M1-36.0

M1-36.5

M1-37.0

M1-37.5

M1-38.0

83/9"

69/11"

82/10"

83/11"

78/10"

Elastic SILT with gravel and sand (cont.)

BORING TERMINATED AT 39.5 FEET

GROUNDWATER NOT ENCOUNTERED

BACKFILLED WITH NEAT CEMENT GROUT

AND SOIL CUTTINGS

101.4

98.1

102.5

102.1

105.5

MH

20.7

22.5

20.9

20.2

21.3

21.9

L

IT

H O

L O

G Y

ENG./GEO.

HAMMER TYPEEQUIPMENT

MATERIAL DESCRIPTION

(B L

O W

S /F

T

R E

S

IS

T A

N C

E

SOIL

SAMPLE

DEPTH

NO.

P E

N E

T R

A T

IO

N

IN

D R

Y D

E N

S

IT

Y

Log of Boring, page 2 of 2

ELEV. (MSL.) DATE COMPLETED 4/7/2017

GEOTECH SAMPLER 3 S1307-05-01 MILLER LAKE DAM.GPJ 05/09/17

SAMPLE SYMBOLS

... SAMPLING UNSUCCESSFUL

(P .C

.F

G R

O U

N D

W A

T E

R

... DISTURBED OR BAG SAMPLE

BORING M1

Automatic Marl M-10 Drill Rig with

8" HSA

DRILLER

C O

N T

E N

T

... STANDARD PENETRATION TEST

... DRIVE SAMPLE (2.0 INCH I.D.)

M O

IS

T

U R

E

Gregg Drilling

FEET (USCS)

Sean Dixon

... WATER TABLE OR SEEPAGE

CLASS

... DRIVE SAMPLE (2.4 INCH I.D.)

NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF

SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.

PROJECT NO. S1307-05-01 PROJECT NAME Miller Lake Dam - Beale AFB

M2-1.0

M2-Bulk

M2-2.0

M2-2.5

M2-3-4.5

M2-5.0

M2-5.5

M2-6.5

M2-8.5-10

M2-10.0

M2-10.5

M2-12.0

M2-12.5

M2-13-14.5

M2-15.5

M2-16.0

M2-17.0

M2-18-19.5

M2-20.5

M2-21.0

M2-22.0

M2-22.5

M2-23-24.5

91/7"

88/11"

94/11"

93/10"

83/10"

83/9"

94/10"

DAM EMBANKMENT

Hard, moist, reddish brown, Sandy lean CLAY with gravel and cobbles

- becomes very stiff

- becomes hard

- becomes very stiff

- becomes hard

- with abundant gravel

IONE FORMATION

Highly weathered SILTSTONE, weak Excavates as: Very dense, moist, gray and brown, Clayey

SAND

Very stiff, moist, light yellowish brown, Elastic SILT

- becomes hard

98.5

99.1

98.1 112.9

106.0

100.8

102.4

CL

SC

MH

13.5

10.3

23.1

17.8

18.3 18.3

17.2

27.9

19.8

L

IT

H O

L O

G Y

ENG./GEO.

HAMMER TYPEEQUIPMENT

MATERIAL DESCRIPTION

(B L

O W

S /F

T

R E

S

IS

T A

N C

E

SOIL

SAMPLE

DEPTH

NO.

P E

N E

T R

A T

IO

N

IN

D R

Y D

E N

S

IT

Y

Log of Boring, page 1 of 2

ELEV. (MSL.) DATE COMPLETED 4/10/2017

GEOTECH SAMPLER 3 S1307-05-01 MILLER LAKE DAM.GPJ 05/09/17

SAMPLE SYMBOLS

... SAMPLING UNSUCCESSFUL

(P .C

.F

G R

O U

N D

W A

T E

R

... DISTURBED OR BAG SAMPLE

BORING M2

Automatic Marl M-10 Drill Rig with

8" HSA

DRILLER

C O

N T

E N

T

... STANDARD PENETRATION TEST

... DRIVE SAMPLE (2.0 INCH I.D.)

M O

IS

T

U R

E

Gregg Drilling

FEET (USCS)

Sean Dixon

... WATER TABLE OR SEEPAGE

CLASS

... DRIVE SAMPLE (2.4 INCH I.D.)

NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF

M2-25.5

M2-26.0

M2-27.0

M2-27.5

M2-28-29.5

M2-30.5

M2-31.0

M2-32.0

M2-32.5

M2-33-34.5

M2-35.5

M2-36.0

M2-37.0

M2-37.5

M2-38-39.5

74/11"

77/11"

Elastic SILT (cont.)

- becomes gray

BORING TERMINATED AT 39.5 FEET

GROUNDWATER NOT ENCOUNTERED

BACKFILLED WITH NEAT CEMENT GROUT

AND SOIL CUTTINGS

108.9

99.8

106.7

103.4

105.5

107.8

MH

19.4

21.7

21.6

19.5

21.0

18.9

L

IT

H O

L O

G Y

ENG./GEO.

HAMMER TYPEEQUIPMENT

MATERIAL DESCRIPTION

(B L

O W

S /F

T

R E

S

IS

T A

N C

E

SOIL

SAMPLE

DEPTH

NO.

P E

N E

T R

A T

IO

N

IN

D R

Y D

E N

S

IT

Y

Log of Boring, page 2 of 2

ELEV. (MSL.) DATE COMPLETED 4/10/2017

GEOTECH SAMPLER 3 S1307-05-01 MILLER LAKE DAM.GPJ 05/09/17

SAMPLE SYMBOLS

... SAMPLING UNSUCCESSFUL

(P .C

.F

G R

O U

N D

W A

T E

R

... DISTURBED OR BAG SAMPLE

BORING M2

Automatic Marl M-10 Drill Rig with

8" HSA

DRILLER

C O

N T

E N

T

... STANDARD PENETRATION TEST

... DRIVE SAMPLE (2.0 INCH I.D.)

M O

IS

T

U R

E

Gregg Drilling

FEET (USCS)

Sean Dixon

... WATER TABLE OR SEEPAGE

CLASS

... DRIVE SAMPLE (2.4 INCH I.D.)

NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF

M3-1.0

M3-Bulk

M3-2.5

M3-3-4.5

M3-5.5

M3-6.0

M3-7.5

M3-8-9.5

M3-10.5

M3-11.0

M3-12.0

M3-12.5

M3-13.0

M3-15.5

M3-16.0

M3-17.0

M3-17.5

M3-18-18.5

M3-20.5

M3-21.0

M3-22.0

M3-22.5

M3-23-24.5

62/9"

83/6"

92/11"

92/9"

DAM EMBANKMENT

Very stiff, moist, reddish brown, Sandy lean CLAY with gravel and cobbles

- becomes hard

- becomes very stiff

- becomes hard, dark brown

IONE FORMATION

Highly Weathered SILTSTONE, weak Excavates as: Hard, moist, light yellowish brown and gray, Elastic SILT

94.5

105.2

97.4

107.7

CL

MH

12.8

17.2 11.7

25.8

15.1

16.1

18.1

13.3

21.1

18.2

L

IT

H O

L O

G Y

ENG./GEO.

HAMMER TYPEEQUIPMENT

MATERIAL DESCRIPTION

(B L

O W

S /F

T

R E

S

IS

T A

N C

E

SOIL

SAMPLE

DEPTH

NO.

P E

N E

T R

A T

IO

N

IN

D R

Y D

E N

S

IT

Y

Log of Boring, page 1 of 2

ELEV. (MSL.) DATE COMPLETED 4/11/2017

GEOTECH SAMPLER 3 S1307-05-01 MILLER LAKE DAM.GPJ 05/09/17

SAMPLE SYMBOLS

... SAMPLING UNSUCCESSFUL

(P .C

.F

G R

O U

N D

W A

T E

R

... DISTURBED OR BAG SAMPLE

BORING M3

Automatic Marl M-10 Drill Rig with

8" HSA

DRILLER

C O

N T

E N

T

... STANDARD PENETRATION TEST

... DRIVE SAMPLE (2.0 INCH I.D.)

M O

IS

T

U R

E

Gregg Drilling

FEET (USCS)

Sean Dixon

... WATER TABLE OR SEEPAGE

CLASS

... DRIVE SAMPLE (2.4 INCH I.D.)

NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF

M3-25.0

M3-25.5

M3-27.0

M3-27.5

M3-28-29.5

M3-30.5

M3-31.0

M3-32.0

M3-32.5

M3-33-34.5

M3-35.5

M3-36.0

M3-37.0

M3-37.5

M3-38-39.5

Elastic SILT (cont.)

Hard, moist, reddish brown, Lean CLAY

Hard, moist, light yellowish brown, Elastic SILT

BORING TERMINATED AT 39.5 FEET

GROUNDWATER NOT ENCOUNTERED

BACKFILLED WITH NEAT CEMENT GROUT

AND SOIL CUTTINGS

108.3

102.4

106.6

106.3

103.1

94.7

MH

CL

MH

20.1

20.7

21.0

21.0

22.9

23.9

L

IT

H O

L O

G Y

ENG./GEO.

HAMMER TYPEEQUIPMENT

MATERIAL DESCRIPTION

(B L

O W

S /F

T

R E

S

IS

T A

N C

E

SOIL

SAMPLE

DEPTH

NO.

P E

N E

T R

A T

IO

N

IN

D R

Y D

E N

S

IT

Y

Log of…