B08 IFB Atch 10 - 20190327_Draft Reach B I-5 Window GDR_022620.pdf

Reach B I-5 Window Geotechnical Data Report American River Common Features Project Geotechnical Support, Natomas Basin Reaches A, B, E-G and Riverside Canal, Sacramento and Sutter Counties, California

U.S. Army Corps of Engineers

Contract No. W91238-16-D-0018 Task Order W9123818F0118

March 27, 2019

DRAFT

AECOM

2020 L Street, Suite 400 Sacramento, CA 95811 aecom.com

March 27, 2019

Khaled Chowdhury, Ph.D, PE, GE U.S. Army Corps of Engineers, Sacramento District 1325 J Street Sacramento CA 95814

Reach B I-5 Window Geotechnical Data Report American River Common Features Project Geotechnical Support, Natomas Basin Reaches A, B, E G and Riverside Canal, Sacramento and Sutter Counties, California

Dear Dr. Chowdhury, AECOM Technical Services, Inc. is pleased to present the attached Reach B, I-5 Window Geotechnical Data Report for the American River Common Features Project. This report is a deliverable under Task 5 of Task Order W9123818F0118.

We appreciate the opportunity to be of service to the U.S. Army Corps of Engineers. Please contact the undersigned if you have any questions.

Sincerely, AECOM Technical Services, Inc.

Shawn Orgill, PE Senior Engineer

Reach B I-5 Window Geotechnical Data Report

Contract No. W91238-16-D-0018 Task Order W9123818F0118

U.S. Army Corps of Engineers AECOM i

Table of Contents

1. Introduction

1.1 Overview

1.2 Purpose and Scope

1.3 Authorization

1.4 Coordinate System and Levee Stationing

2. Background Information

2.1 Non-Federal Sponsor, Maintenance Agency, and Stakeholders

2.2 Geologic and Geomorphic Setting

2.3 Construction History

2.3.1 Original Construction

2.3.2 Post-Construction Improvements

2.4 Performance History

3. Current Subsurface Investigation

3.1 Rationale for Explorations

3.2 Permitting and Utility Clearance

3.3 Biological and Cultural Clearance

3.4 Field Exploration

3.4.1 Exploration Locations

3.4.2 Hand Auger Borings

3.4.3 Sampling and Classification

3.4.4 Exploration and Sample Identification

3.4.5 Backfilling and Surface Restoration

3.5 Laboratory Testing

4. Historical Field Explorations

4.1 Wahler Associates Explorations (1989)

4.2 URS Explorations (2001 and 2007)

4.3 Kleinfelder Explorations (2005, 2008-2009)

5. Subsurface Conditions

5.1 Geologic Plans and Profiles

5.2 Groundwater Conditions

6. Acknowledgements and Limitations

6.1 Acknowledgements

6.2 Limitations

7. References

Reach B I-5 Window Geotechnical Data Report

Contract No. W91238-16-D-0018 ii

Appendices

Appendix A Geologic Plans and Profiles Appendix B Hand Auger Boring Logs (Current Investigation) Appendix C Laboratory Test Results (Current Investigation) Appendix D Historical Wahler Associates Boring Logs, and Laboratory Test Results Appendix E Historical URS Boring Logs and Laboratory Test Results Appendix F Historical Kleinfelder CPT Signature Plots, Boring Logs, and Laboratory Test Results Appendix G Kleinfelder Piezometer Report Summary

Figures

Figure 1. Vicinity Map Figure 2. Natomas Basin Reaches Figure 3. Natomas Basin Reach B Map Figure 4. Typical Cross Section from Original Levee Construction Figure 5. Piezometer Location Map

Tables

Table 1. Exploration Locations – Current Hand Auger Investigation Table 2. Historical Exploration Locations

Acronyms and Abbreviations

AECOM AECOM Technical Services, Inc.

ARCF American River Common Features bgs below ground surface DWR California Department of Water Resources GDR Geotechnical Data Report Kleinfelder Kleinfelder, Inc.

NAD83 North American Datum of 1983 NAVD88 North American Vertical Datum of 1988 NGVD29 National Geodetic Datum of 1929 NLIP Natomas Levee Improvement Program RD 1000 Reclamation District 1000 SAFCA Sacramento Area Flood Control Agency SPT Standard Penetration Test SRFCP Sacramento River Flood Control Project SUALRP Sacramento Urban Area Levee Reconstruction Project URS URS Corporation USACE U.S. Army Corps of Engineers WRDA Water Resources Development Act

Reach B I-5 Window Geotechnical Data Report Contract No. W91238-16-D-0018

1. Introduction

This Geotechnical Data Report (GDR) presents the results of a geotechnical investigation by AECOM Technical Services, Inc. (AECOM) for the Reach B I-5 Window completed in November, 2018 and summarizes results of previous pertinent investigations. This GDR will be used in support of geotechnical problem identifications, alternatives evaluations, and geotechnical design of improvements to a portion of the Sacrament East levee on the southwestern portion of the Natomas Basin in Sacramento, California.

The investigation work presented in this GDR represents that hand auger explorations and historical explorations performed within a roughly 2,000 feet gap in the existing cutoff wall improvement near Interstate 5 (herein referred to as the I-5 Window). The Natomas Basin is located in Sacramento and Sutter counties and is surrounded by levee embankments (Figure 1). The Natomas Basin is bounded to the north by the Natomas Cross Canal, to the west by the Sacramento River, to the south by American River, and to the east by the Natomas East Main Drainage Canal and the Pleasant Grove Creek Canal.

For planning purposes, the U.S. Army Corps of Engineers (USACE) has divided the levee segments surrounding the Natomas Basin into nine reaches; Reaches A to I. USACE’s planning reaches are shown on Figure 2.

The I-5 Window is located along the east (left) bank of the Sacramento River within Reach B, between Station 435+00 and Station 455+50 and is approximately 2,000 feet long. Levee improvement measures have been implemented in the area upstream and downstream of the I-5 Window under the Natomas Levee Improvement Program (NLIP) by the Sacramento Area Flood Control Agency (SAFCA) from 2010 to 2011. Figure 3 shows the extent of the Reach B I-5 Window Study Area.

1.1 Overview

The I-5 Window Study Area levee is a part of the Sacramento River Flood Control Project (SRFCP). The SRFCP is an integrated system of levees, overflow bypass channels, and dams that were designed and constructed by federal, State, and local interests. The 1986 high water event exposed numerous performance deficiencies in the SRFCP. To address these deficiencies in the Sacramento area, USACE proposed quick implementation of a levee improvement project along the Sacramento River levee that protects the Natomas Basin, downtown Sacramento, Sacramento International Airport, and the Pocket area. USACE also proposed consideration of a comprehensive program of levee improvements along the diversion channels around Natomas, combined with a flood control dam near Auburn, to control flows in the lower American River. However, the flood control dam portion later was removed from this program.

The levee stabilization portion of the program was referred to as the Sacramento Urban Area Levee Reconstruction Project (SUALRP) and employed two measures to address the seepage issues: drained stability berms and shallow cutoff walls. Construction of these improvements, covering approximately 33 miles of the Sacramento River east levee, was initiated in 1990 and completed in 1993. Following completion of the SUALRP, levee improvements related to overtopping concerns or levee height deficiencies around the Natomas Basin and other diversion channels were constructed by SAFCA.

SAFCA’s work was substantially completed in 1996. That same year, a Supplemental Information Report that identified the ongoing risk of flooding in the Sacramento area was completed by USACE. Based on the Supplemental Information Report, Congress then directed USACE to initiate improvements to the levees along the American River and to study the residual risk of flooding from the levees along the Sacramento River east levee downstream from the Natomas Cross Canal. These improvements were considered a common element of any long-term effort to provide flood protection to Sacramento, and the project was referred to as the American River Common Features (ARCF) Project. The ARCF Project was authorized by the Water Resources Development Act (WRDA) (Public Law 104-303) of 1996.

The storms of 1997 again produced high water events along the Sacramento and American Rivers. The improved levees around the Natomas Basin passed these flows without the signs of distress observed in 1986. However, the flood caused breaches of some SRFCP levees along the Feather River and Sutter Bypass upstream from Natomas. The USACE post-flood assessment concluded that underseepage may have contributed to these levee failures. To address the risk of underseepage in the Sacramento area, USACE recommended a broader scope for the ARCF Project, advocating construction of deep seepage cutoff walls through the levees along the lower American River and calling for an assessment of the need for similar measures along the east levee of the Sacramento River in the Natomas Basin. These recommendations were authorized by Congress in Section 366 of the WRDA of 1999 (Public Law 106 53). The WRDA of 1999 also authorized improvements to the Natomas Cross Canal south levee.

After determining that project remedial features specific to the Natomas Basin were likely to exceed the authorized project cost, USACE initiated a General Reevaluation Report (USACE, 2015) in 2002, focusing on the Natomas Basin portion of the project. The Natomas Post-Authorization Change Report and Interim General Reevaluation Report (USACE, 2010) was completed and approved in 2010. An expansion of the Natomas Basin portion of the ARCF Project was authorized in Section 7002 of the Water Resources Reform and Development Act of 2014 (Public Law 113-121).

Following a review of USACE guidelines for evaluating levee performance, the Sacramento District re-assessed the levees surrounding the Sacramento area. In 2006, the Federal Emergency Management Agency withdrew certification of the levee system surrounding the Natomas Basin.

At the same time that USACE initiated efforts associated with the General Reevaluation Report (USACE, 2015) for the Natomas Basin, SAFCA initiated the Natomas Levee Evaluation Study, which became the NLIP. The purpose of the NLIP was to provide 200-year level of protection for the Natomas Basin through structural improvements to the levees surrounding the basin. As part of NLIP, improvements were constructed for a portion of Reach B upstream and downstream of the Study Area included in this GDR.

Following the ARCF Project authorization by the Water Resources Reform and Development Act of 2014, USACE has undertaken a design level study of the I-5 Window Study Area. This GDR is a deliverable under Task 5 of the Statement of Work for Task Order W9123818F0118, titled Geotechnical Engineering Services, American River Common Features Project, Natomas Basin, Reaches A, B, E, F, G, and Riverside Canal, Sacramento and Sutter Counties, CA (USACE, 2018).

1.2 Purpose and Scope

Field investigation for this GDR entailed collecting geotechnical information to supplement existing data.

The new and existing geotechnical data will be used in support of USACE’s final design for the Natomas Basin I-5 Window area.

AECOM’s scope of work for this GDR included:

Reviewing existing historical geotechnical information and summarizing pertinent data in an inventory.

Performing 9 hand auger borings along the slope and toe of an existing landside stability berm

Performing geotechnical laboratory testing of selected samples collected from the hand auger borings.

Updating USACE’s existing plans and profiles with exploration data collected as part of this GDR.

Preparing this GDR.

1.3 Authorization

USACE authorized the work described in this GDR under Contract W91238-16-D-0018 Task Order W9123818F0118.

1.4 Coordinate System and Levee Stationing

Unless noted otherwise, all elevation references in this GDR are in feet based on the North American Vertical Datum of 1988 (NAVD88). The horizontal datum is the North American Datum of 1983 (NAD83).

Survey data, elevations and horizontal coordinates are in feet based on California State Plane, Zone 2.

Some historical information is provided in National Geodetic Datum of 1929 (NGVD29). The conversion factor from NGVD29 to NAVD88 is +2.28 feet. The levee stationing is a project-specific stationing system provided by USACE. The upstream (northern) limit for the Reach B I-5 Window Study Area is at Station 435+00, about 800 feet northwest of the west bound I-5 lanes. The downstream (southern) limit for this portion of the Study Area is at Station 455+00+00 about 950 feet downstream of east bound lanes of I-5.

The levee stationing is shown on Figure 3.

Figure 1. Vicinity Map

Figure 2. Natomas Basin Reaches

Figure 3. Natomas Basin Reach B Map

2. Background Information

2.1 Non-Federal Sponsor, Maintenance Agency, and Stakeholders The Central Valley Flood Protection Board is the non-federal sponsor for the Reach B I-5 Window Study Area levee. Reclamation District 1000 (RD 1000) is the local maintaining agency. SAFCA was formed in 1989 through a joint powers agreement executed by the City of Sacramento, the County of Sacramento, the County of Sutter, the American River Flood Control District, and RD 1000 to provide increased flood protection along the American and Sacramento Rivers. SAFCA and RD 1000 participate as part of the project delivery team for the Reach B Study Area levee.

2.2 Geologic and Geomorphic Setting

The Reach B I-5 Window Study Area is near the confluence of two major rivers, the Sacramento River and American River. The geomorphic maps of the Reach B Study Area are overlain on the plan view of the plan and profiles (Appendix A).

The Reach B Study Area levee is in the Sacramento Valley in the northern part of the Great Valley geomorphic province. The Great Valley geomorphic province is a large, elongated structural trough that contains a thick sequence of predominantly sedimentary formations that range in age from Jurassic (206 to 144 million years old) to Recent. From the late Triassic Period until the late Jurassic, this area was part of the continental shelf and ocean floor on which the marine Great Valley sequence was deposited. By the early Pleistocene Epoch (about 1.8 million years ago), after uplift of the Coast Ranges, the present boundaries of the Great Valley were well developed, and deposition changed from marine to mostly continental. Surficial units within the project area are predominantly Pleistocene and Holocene alluvial deposits.

Within the Sacramento area, the Sacramento and American rivers have been confined by manmade levees since the early 1900s. The levee in this study area was generally constructed on Holocene-age alluvial and fluvial sediments deposited by the current and historical Sacramento River. Pleistocene deposits are mapped nearby and underlie Holocene deposits.

Historical overbank deposits comprise the majority of sediments beneath Reach B I-5 Window Study Area levee. The river along the Sacramento River East Levee includes the watersheds of both the Feather and Sacramento rivers, and thus was often prone to flooding. Because of this flooding and associated sedimentation, the banks of the river are comprised of silty sand deposits that form natural levees. The natural levees are a geomorphic landform comprised of individual deposits. Here the levee primarily overlies natural levee deposits, including crevasse splay (map units: Rcs, Hcs), and overbank (map units:

Rob, Hob) deposits. Overbank deposits are slightly finer-grained sand, silt, and clay deposited via sheet flow when the river is at flood-stage and overtops natural and artificial levees. The depositional process associated with these map units results in laterally and vertically discontinuous sediments in the shallow subsurface.

Surficial geologic mapping and geomorphic analysis shows a complex distribution of fluvial and alluvial deposits at the surface, near-surface, and subsurface in the Reach B I-5 Window Study Area. The surface distribution of sediment is, generally, a function of lateral distance from the river channel and topographic elevation. Sediments are relatively coarse proximal to the river, and relatively finer distal to the river in low-lying areas. The subsurface distribution of sandy and gravelly deposits is probably a function of former river positions or meander belts on the landscape.

Migration of the Sacramento River has created paleochannels in these Holocene deposits. More recently, flooding events have created natural levees consisting of generally coarse materials at the banks of the rivers. Crevasse splays consisting of coarse to fine material developed where natural levees breached. In general, progressively finer-grained materials are deposited farther from the river bank forming backwater deposits.

In general, the levee in the Reach B Study Area is constructed on the natural floodplain of the Sacramento River, and are commonly located at or near the top of the bank of the river. These materials commonly are loose and unconsolidated. Holocene and younger deposits typically overlie Pleistocene alluvium. Thus, in the subsurface beneath the levee, sediments of Modesto-age (and older) channels and floodplain may be present. The gross stratigraphy beneath the Sacramento River floodplain consists of fluvial sediments that generally form a fining-upward sequence from gravel and sand, sand and silty sand, to silt and sandy silt. The relative compaction of these sediments decreases upward, becoming progressively looser and softer closer to the ground surface. In many instances, the present-day levee overlies both wide and narrow abandoned channels. The abandoned channels may contain locally coarser-grained material that extends beneath the levee in different trends (e.g., oblique, orthogonal).

2.3 Construction History

2.3.1 Original Construction

Natomas Consolidated of California, a private mining and dredging company, began construction of the Natomas Basin levees along the Sacramento River in 1909 with the purpose of reclaiming and selling thousands of acres of new farmland. The work involved constructing a 40-mile-long perimeter levee system using five large clam shell dredging machines named the Thor, Hercules, Samson, Ajax, and Vulcan, and by using a large suction dredge called the Natomas. Work on the Natomas Basin levees began in 1912, and was completed by the end of 1915. Upon completion, the district’s new levee system resulted in reclamation of approximately 53,000 acres in the Natomas Basin.

During the original construction, dragline scrapers excavated a core trench and formed retaining dikes to hold the dredged levee core materials. The core was filled with materials from the bottom of the river by a suction dredge. The suction dredge Natomas pumped materials into the excavation until the desired elevation was achieved. This practice was favored when the levee alignment was located out of reach of a long-boom clam shell dredge. Figure 4 shows a schematic of a composite levee section with two retaining dikes and inner core trench. This levee construction procedure was used in the Sacramento River East Levee in Natomas. Based on the available information, the cutoff trench was about 12.5 feet deep; approximately 35 feet wide at the top and 28.5 feet wide at the bottom.

Figure 4. Typical Cross Section from Original Levee Construction

2.3.2 Post-Construction Improvements

In 1991, the USACE constructed a landside drained stability berm about 10 feet wide and 5 feet tall under the SUALRP.

2.4 Performance History

Historical past performance records document significant flood events along the Reach B Study Area in the 1938, 1963, 1986, and 1997 flood seasons. Historical seepage was reported throughout the Reach B Study Area and shown on seepage maps from 1963 and 1965 prepared by the State of California Department of Water Resources (DWR). In addition, during the 1986 high water event, multiple instances of slope stability distress related to through seepage were observed on the landside slope. However, no specific information (e.g., location, severity, etc.) about the distress is available. No breaches or erosion have been reported.

3. Current Subsurface Investigation

AECOM performed field investigations for the Reach B I-5 Window Study Area in November 2018. During this investigation, AECOM performed 9 hand augers to depths ranging from 3.5 feet to 5 feet below ground surface (bgs).

3.1 Rationale for Explorations

Exploration locations were selected by USACE at targeted locations to:

Characterize the existing stability berm fill and foundation blanket materials;

Collect samples of embankment and blanket material for geotechnical index property testing; this information will be used to support design of improvements.

3.2 Permitting and Utility Clearance

AECOM obtained the following approvals prior the start of Reach B I-5 Window Study Area hand auger field explorations:

Drilling permits from the Sacramento County Environmental Management Department Environmental Compliance Division

Encroachment permit from the County of Sacramento

Temporary Use Permit and Hold Harmless Agreement from RD 1000

AECOM visually inspected each planned exploration location for the presence of overhead and underground utilities. The locations were then staked and marked with white paint. Underground Service Alert was contacted a minimum of 48 hours prior to the start of exploration activities. An Underground Service Alert ticket number (including clearance date, expiration date and call-back-to-extend date) was obtained for each planned exploration location and was documented in the project file.

3.3 Biological and Cultural Clearance

Geotechnical investigation activities could potentially affect special-status species, wetlands, and sensitive natural communities that are protected under state, federal, and local laws, ordinances, and regulations. USACE performed a desktop study that included reviewing the California Natural Diversity Database and a field reconnaissance of the Reach B I-5 Window Study Area alignment to identify sensitive biological resources that might be affected in areas of exploration activities. No special biological restrictions were identified by USACE for this work.

AECOM evaluated the presence of potentially sensitive cultural resources, or prehistoric/historical archaeological resources. The evaluation included a record search of files maintained at the North Central Information Center of the California Historical Resources Information System at California State University, Sacramento and a pedestrian survey of the entire stretch of levee within the current project area. AECOM provided USACE a letter report that summarized the results of the record search and the pedestrian survey. USACE personnel corresponded with local Native American tribes regarding the presence of sensitive historical tribal sites. An AECOM archaeological monitor provided a briefing to the field loggers and field crews on actions required if cultural resources were observed or suspected. Daily field surveys were also conducted by the AECOM cultural monitor prior to mobilization to each exploration site. The AECOM cultural monitor inspected the cuttings from the hand augers and soil samples obtained for the presence of sensitive material, and maintained records for all exploration locations. Cultural resource evaluation results are confidential, and the explorations avoided any potentially sensitive areas.

AECOM submitted daily reports on the monitoring activities to USACE for the duration of the geotechnical investigation.

3.4 Field Exploration

Nine hand auger explorations were performed by AECOM on November 14, 2018 in the Reach B I-5 Window Study area, on the landside seepage berm and along the toe of the berm.

3.4.1 Exploration Locations

Locations and ground surface elevations for the hand auger borings are provided in Table 1. The locations were surveyed by MHM in December 2018.

3.4.2 Hand Auger Borings

Hand auger borings were performed at 9 locations in the Reach B Study Area by AECOM in November 2018. The hand auger borings were advanced to depths ranging from 3.5 to 5 feet bgs.

Classification of soil materials, samples collected, and laboratory analysis results are presented on the hand auger boring logs in Appendix B.

3.4.3 Sampling and Classification

An AECOM geologist logged samples from each exploration in the field in general conformance with ASTM D2488. The logs were subsequently reviewed and updated as needed per ASTM D2487 (Unified Soil Classification System) based on laboratory testing results of select samples.

For hand auger borings, bag samples were collected at 1 to 2 foot intervals. Samples were collected in a gallon Ziploc bag and sealed to prevent moisture loss.

Table 1. Exploration Locations – Current Hand Auger Investigation

Exploration ID Exploration Location Date Completed

Type Approximate Surface Elevation (ft, NAVD88)

Station (ft) Approximate Coordinates (California State Plane, Zone 2)

Total Depth (ft)

Approximate Offset (ft) from centerline

Northing (ft) Easting (ft)

4F-17-01 Landside Stability Berm Toe 2018 Hand Auger 30.3 442+25 2007399.49 6668922.16 5.00 68.27

4F-17-02 Landside Stability Berm Toe 2018 Hand Auger 28.8 443+03 2007342.84 6668975.46 5.00 66.30

4F-17-03 Landside Stability Berm Slope 2018 Hand Auger 33.8 443+01 2007331.60 6668960.89 5.00 48.04

4F-17-04 Landside Stability Berm Toe 2018 Hand Auger 27.1 444+40 2007241.90 6669068.59 3.50 61.48

4F-17-05 Landside Stability Berm Slope 2018 Hand Auger 31.7 444+39 2007232.73 6669056.67 3.50 46.57

4F-17-06 Landside Stability Berm Toe 2018 Hand Auger 26.9 444+95 2007205.20 6669109.29 5.00 64.59

4F-17-07 Landside Stability Berm Toe 2018 Hand Auger 26.8 445+91 2007136.69 6669175.83 5.00 63.69

4F-17-08 Landside Stability Berm Slope 2018 Hand Auger 32.6 445+91 2007121.39 6669160.84 5.00 42.28

4F-17-09 Landside Stability Berm Toe 2018 Hand Auger 26.7 447+04 2007056.12 6669255.58 5.00 63.70

3.4.4 Exploration and Sample Identification

At field program startup, each exploration was assigned a unique number by USACE to differentiate it from previously completed exploration programs. Table 1 presents exploration numbering for this investigation.

Samples were identified and labeled with the applicable exploration and sample numbers. Descriptions of exploration numbering and sample identification protocols are provided below.

Explorations were identified according to the following protocol:

Samples were numbered according to the following protocol:

Each sample was assigned a unique number. The samples were numbered chronologically (i.e., the first sample recovered from a given boring was given the number S01, the second S02, and so forth).

Samples follow the same numbering sequence, regardless of type of sample. A one-letter descriptor at the end of the sample identified the sample type. For the hand auger borings, soil samples were placed in bags, therefore, “B” is the sample type for bag.

3.4.5 Backfilling and Surface Restoration

Following completion of the hand auger borings, the locations were backfilled with a hydrated mixture of bentonite chips and native soil to match existing grade.

3.5 Laboratory Testing

Laboratory testing was performed on selected samples collected from the hand auger borings. Laboratory testing was performed by Geocon Consultants, Inc. of Rancho Cordova, California. Laboratory test results are provided in C. The laboratory testing included:

Index Tests

─ Sieve Analyses (ASTM D6913)

─ Hydrometer (ASTM D 7928)

─ Atterberg Limits (ASTM D4318)

─ Moisture Content (ASTM D2216)

4F=Hand Auger 2 Digit Borehole Number

4F-17-01

Fiscal Year Performed = 2017

S02_01_02B

S=Sample

2-Digit Sample Number

Sample Position – Top of Interval

Bottom of Sample Interval

B=Bag Sample

4. Historical Field Explorations

Multiple field investigations were previously performed in the Reach B I-5 Window Study area by Kleinfelder, Inc. (Kleinfelder), URS Corporation (URS), USACE, and Wahler Associates, Inc. Past investigations included the completion of soil borings, CPTs, and associated laboratory tests on soil samples. These investigations are summarized in this section. Historical explorations and explorations from AECOM’s current hand auger investigation are both summarized on the geologic plans and profiles (Appendix A). Previous investigations in the Reach B I-5 Window Study Area are discussed below, from oldest to most recent.

4.1 Wahler Associates Explorations (1989)

In 1989, Wahler Associates advanced one hollow stem soil boring to a depth of 30 feet on the levee crest in the Reach B I-5 Window Study Area (Wahler, 1989). Laboratory testing was performed on selected samples collected from this boring and included:

Index Tests

─ Sieve Analyses

─ Atterberg Limits

─ Moisture Content

The location of the Wahler Associates boring is provided in Table 2, and on Plan and Profiles in Appendix A, Boring log and laboratory data is provided in Appendix D.

4.2 URS Explorations (2001 and 2007)

In 2001, URS performed 2 mud rotary soil borings in the landside field in the Reach B I-5 Window Study Area (URS, 2002). The borings were drilled to depths ranging from 40 to 50 feet bgs. Then in 2007, URS completed three mud rotary borings, one on the landside toe and two borings in the landside field, in the Reach B I-5 Window Study Area (URS, 2008). The borings were advanced to depths ranging from 61.5 feet to 101.5 feet. Laboratory testing was performed on selected samples collected from these borings and included:

Index Tests

─ Sieve Analyses

─ Hydrometer Analyses

─ Atterberg Limits

─ Moisture Content

─ Dry Unit Weight

Falling Head Tests

Permeability Tests

The locations of the URS borings are provided in Table 2, and on Plan and Profiles in Appendix A. The boring logs and the laboratory results from these explorations are provided in Appendix D.

4.3 Kleinfelder Explorations (2005, 2008-2009)

In 2005, Kleinfelder drilled one boring along the landside toe, to a depth of 81.5 feet, in the Reach B I-5 Window Study Area). Later, in 2008, Kleinfelder performed two mud rotary soil borings along the landside toe in the Reach B I-5 Window Study Area (Kleinfelder, 2010). These 2008 borings were drilled to depths ranging from 81.5 to 116.5 feet bgs. In 2009, Kleinfelder drilled 8 mud rotary borings along the landside field and on the levee crest, to depths ranging from 66.0 feet to 103.00 feet. Laboratory testing was performed on selected samples collected from these borings and included:

Index Tests

─ Sieve Analyses

─ Atterberg Limits

─ Moisture Content

─ Dry Unit Weight

Strength Tests

─ Consolidated Undrained

─ Triaxial Compression

─ Direct Shear

Falling Head Tests

In addition, Kleinfelder performed 13 CPT soundings in 2009, along the levee crest, landside toe and landside field in the Reach B I-5 Window Study Area. The CPT soundings were advanced by John Sarmiento and Associates using a 20-ton CPT rig to depths ranging from 65.12 to 110.01 feet bgs. The locations of the Kleinfelder borings and CPTs are provided in Table 2, and on Plan and Profiles provided in Appendix A. The boring logs, CPT logs, and laboratory data from these explorations are provided in Appendix F.

Table 2. Historical Exploration Locations

Exploration ID Exploration Type

Depth (ft)

Location Date Completed

Drilling / CPT Contractor Approximate Surface Elevation (ft)

Approximate Station (ft)

Offset (ft)*

Coordinates (California State Plane, Zone 2)

Northing (ft) Easting (ft)

RD1000-DH-11-2 Boring 30.00 Levee Crest 1989 PC Exploration 41.7 451+01 7.89 2006734.90 6669495.00

2F-01-54 Boring 50.00 Landside Field 2001 Westex 28.7 437+64 153.78 2007787.05 6668668.02

2F-01-55 Boring 40.00 Landside Field 2001 Westex 27.2 438+00 298.67 2007857.06 6668800.01

SRB-27 Boring 81.50 Landside Toe 2005 Kleinfelder 38.4 448+50 30.14 2006928.56 6669334.62

URS071000_438+00R Boring 101.50 Landside Field 2007 Taber Consultants 32.2 437+97 -105.13 2007589.00 6668498.00

URS071000_451+00F Boring 68.00 Landside Field 2007 Taber Consultants 25.1 452+09 190.25 2006786.00 6669701.00

URS071000_451+00T Boring 61.50 Landside Toe 2007 PC Exploration 24.5 450+99 88.56 2006793.00 6669551.00

SRE-08- 89 Boring 81.50 Landside toe 2008 Kleinfelder 25.1 453+33 77.58 2006618.86 6669707.92

SRE-08- 90 Boring 116.50 Landside toe 2008 Kleinfelder 30.5 442+29 65.61 2007395.00 6668922.86

CPT-09-106 CPT 95.07 Levee Crest 2009 John Sarmiento and Associates 41.5 435+99 -0.28 2007806.91 6668444.48

CPT-09-107 CPT 95.08 Levee Crest 2009 John Sarmiento and Associates 41.9 442+90 0.00 2007305.73 6668918.90

CPT-09-108 CPT 92.02 Levee Crest 2009 John Sarmiento and Associates 41.8 444+00 0.00 2007227.55 6668996.28

CPT-09-109 CPT 95.03 Levee Crest 2009 John Sarmiento and Associates 41.7 445+00 0.00 2007156.48 6669066.63

CPT-09-155 CPT 70.21 Landside toe 2009 John Sarmiento and Associates 30.4 439+23 49.23 2007600.97 6668698.04

CPT-09-156 CPT 70.04 Landside Field 2009 John Sarmiento and Associates 27.3 440+36 156.26 2007595.51 6668852.30

CPT-09-158 CPT 70.06 Landside Field 2009 John Sarmiento and Associates 26.3 444+42 150.87 2007303.38 6669133.51

CPT-09-159 CPT 65.12 Landside Field 2009 John Sarmiento and Associates 26.4 445+47 141.76 2007222.83 6669200.41

CPT-09-61 CPT 108.52 Levee Crest 2009 John Sarmiento and Associates 41.5 440+00 -0.30 2007511.86 6668715.28

CPT-09-62 CPT 106.02 Levee Crest 2009 John Sarmiento and Associates 41.7 442+00 0.00 2007369.70 6668855.59

CPT-09-63 CPT 90.09 Landside Toe 2009 John Sarmiento and Associates 29.2 446+50 55.82 2007088.74 6669212.21

CPT-09-64 CPT 103.05 Levee Crest 2009 John Sarmiento and Associates 41.7 448+00 0.00 2006943.34 6669277.59

CPT-09-65 CPT 110.01 Levee Crest 2009 John Sarmiento and Associates 41.7 452+00 0.00 2006659.02 6669559.01

SRE-09- 28 Boring 86.50 Levee Crest 2009 Kleinfelder 41.5 438+00 -0.18 2007657.00 6668578.00

SRE-09- 29 Boring 60.00 Landside Field 2009 Kleinfelder 27.2 437+97 299.94 2007860.30 6668798.80

Exploration ID Exploration Type

Depth (ft)

Location Date Completed

Drilling / CPT Contractor Approximate Surface Elevation (ft)

Approximate Station (ft)

Offset (ft)*

Coordinates (California State Plane, Zone 2)

Northing (ft) Easting (ft)

SRE-09- 48 Boring 81.50 Landside Field 2009 Kleinfelder 28.2 440+42 231.66 2007643.29 6668911.00

SRE-09- 49 Boring 81.50 Landside Field 2009 Kleinfelder 27.0 440+51 389.14 2007747.04 6669029.76

SRE-09- 50 Boring 73.00 Landside Field 2009 Kleinfelder 25.7 444+23 216.41 2007363.44 6669166.28

SRE-09- 51 Boring 103.00 Landside Field 2009 Kleinfelder 29.0 444+16 357.32 2007467.19 6669261.84

SRE-09- 52 Boring 66.00 Landside Field 2009 Kleinfelder 26.0 445+90 193.14 2007228.29 6669267.30

SRE-09- 53 Boring 98.00 Landside Field 2009 Kleinfelder 24.0 445+92 365.94 2007348.43 6669391.52

* Positive offsets are to the landside of the levee centerline, Negative offsets are to the waterside of the levee centerline

5. Subsurface Conditions

5.1 Geologic Plans and Profiles

Subsurface soil conditions are summarized on geologic plans and profiles (Appendix A). USACE provided draft geologic plans and profiles for the Reach B I-5 Window Study Area including the historical field explorations described in Section 4. As part of this GDR, AECOM updated the geologic plans and profiles to include data collected during the current subsurface investigation identified in Section 3.

The geotechnical explorations are presented on the geologic plans and profiles in a simplified “stick-log” format. Soil borings are shown in a profile view and show selected field test and laboratory test data, including soil type, standard penetration test (SPT) blow counts, sampler type, fines content, and plasticity index. For historical explorations where hammer energy efficiency information is available, SPT blow counts corrected for hammer system efficiency and sampler dimensions (N60 values) are shown. For historical explorations where hammer efficiency information is not available, uncorrected field SPT blow counts (Nf) are shown. CPT data is shown, including friction ratio and tip resistance.

The profiles in Appendix A are presented along with a plan view of the levee, showing exploration locations, the levee alignment and stationing, levee miles, geologic mapping, and road crossings.

5.2 Groundwater Conditions

Groundwater conditions in the I-5 Window section of the Reach B Study area fluctuate based on several factors, including the Sacramento River Stages, rainfall, irrigation practices, and other factors. Historical groundwater data in the area is limited and include limited piezometer monitoring.

Groundwater depths were measured by Kleinfelder at the I-5 Well, located south of the I-5 overpass near Station 449+00, during both the 2016-2017 flood season and the 2017-2018 flood season. Groundwater elevations ranged from a low of 8.9 feet (November 30, 2016) to a high of 25.0 feet (February 20, 2017) during the 2016-17 flood season, and 8.9 feet (December 17, 2017) to 15.2 feet (April 13, 2018) during the 2017-18 flood season. The groundwater readings are provided in the NAVD88. The location of the I-5 well is shown on Figure 5. Groundwater readings are graphically represented in the Piezometer Reading Summary for the 2016-2017 Flood Season (Kleinfelder 2017), and the 2017-2018 Flood Season (Kleinfelder 2018), provided in Appendix G.

It is common for the groundwater level to be at or near the landside ground surface during elevated river stage in the adjacent Sacramento River. Artesian conditions are also possible. In addition, wet soil conditions will persist following elevated river conditions and/or irrigation near the levee.

Figure 5. Piezometer Location Map

6. Acknowledgements and Limitations

6.1 Acknowledgements

AECOM’s key team members for preparation of this report are listed below:

Juan Sorensen, PE, GE: Task Order Manager

Shawn Orgill, PE: Deputy Task Order Manager

Mehrzad Maghsoudlou, PG: Field Investigations Lead

Rich Millet, PE, GE: Senior Technical Reviewer

Francke Walberg, PE: Independent Technical Review

Diana Ewing: Cultural Resources

Tiffany Carrasco-Cabana: GIS Specialist

David Pieczynski: Senior Geologist

KC Coon: Data Management

Subcontractors used by AECOM for this work include:

Geocon, Incorporated: Laboratory Testing

This report was prepared in coordination with USACE, SAFCA, DWR, RD 1000, and Kleinfelder. AECOM would like to thank them for support for this GDR.

USACE

John Hoge, PE: Project Manager

John Powderly, PE: Project Manager

Mark Boedtker, PE: Technical Lead

Khaled Chowdhury, PhD, PE, GE: Geotechnical Lead

Sandy Knapp, PE: Geotechnical Engineering

George Hu, PE: Geotechnical Engineering

Joseph Waltz, PE: Geotechnical Engineering

Robin Rosenau: Environmental Lead

Robert Gudino: Cultural Resources Lead

SAFCA

John Bassett, PE: Director of Engineering

DWR

Sean Smith: Project Manager

RD 1000

Paul Devereux, PE: General Manager

Donald Caldwell: Superintendent

Kleinfelder

Tim Williams, PE, GE

Becky Money, PE, GE

6.2 Limitations

The geotechnical analyses, associated data, and report preparation have been performed in accordance with the standard of care commonly practiced in the engineering profession. Standard of care is defined as the ordinary diligence exercised by fellow practitioners in this area performing the same services under similar circumstances during the same time period.

Discussions of subsurface conditions summarized in this report are based on subsurface soil and groundwater conditions at limited exploration locations and at limited times. In addition, in non-homogenous subsurface conditions such as were encountered in the Reach B Study Area, water levels may represent an average level. Variations in subsurface conditions almost certainly exist between exploration locations and between times, and AECOM may not be able to discern or present all adverse conditions in the levee and its foundation.

No warranty, express or implied, is made in the furnishing of this report. AECOM makes no warranty, express or implied, that actual encountered site and subsurface conditions will exactly conform to the conditions described herein, or that interpretations and recommendations in this report will be sufficient for all construction planning aspects of the work. A sufficient number of additional explorations necessary to verify subsurface conditions should be performed rather than relying solely on the information presented in this report. AECOM does not attest to the accuracy, completeness, or reliability of geotechnical borings and other subsurface data by others that are included or referenced in this report.

AECOM has not performed independent validation or verification of data by others.

Data presented in this report are time-sensitive in that they apply only to locations and conditions existing at the time of the exploration or collection of the data. Data should not be applied to any other projects in or near the area of this study; nor should they be applied at a future time without appropriate verification.

This report is for the use and benefit of USACE and their consultants in connection with the execution of the Natomas Basin Reach B Study Area levee improvement project. Use by any other party is at their own discretion and risk.

7. References

Kleinfelder. 2006a. Problem Identification Report Sacramento River East Levee Natomas Basin Evaluation Reclamation District 1000. February.

———. 2006b. Piezometer Reading Summary, Sacramento and American Rivers, Sacramento and Sutter Counties, California. December.

———. 2010. Geotechnical Data Report, Sacramento River East Levee, SREL 2 (Reaches 5 through 9), Natomas Levee Improvement Program, Sacramento and Sutter Counties, California. January.

———. 2018a. Piezometer Reading Summary, 2016-2017 Flood Season Natomas Cross Canals, Sacramento and American Rivers, Sacramento and Sutter Counties, California. February.

———. 2018b. Piezometer Reading Summary, 2017-2018 Flood Season Natomas Cross Canals Sacramento and American Rivers Sacramento and Sutter Counties, California. June.

URS. 2000. Revised Geotechnical Report, Volume 1 – Main Report: American River Watershed Project (Common Features), California, Sacramento River East Side Levee and Berm Raising. February.

———. 2002. Landside and Waterside Explorations Report, American River Watershed project (Common Features), Sacramento River East Side and Berm Raising, Sacramento, California.

March.

———. 2008. Subsurface Investigation Report for Sacramento River East Levee, Natomas General Re-evaluation Report, American River Watershed Project (Common Features), California. June.

USACE. 2010. Post-Authorization Change Report and Interim General Reevaluation Report, American River Watershed Common Features Project, Natomas Basin, Sacramento and Sutter Counties, California. August.

———. 2015. American River Watershed Common Features General Reevaluation Report. February.

———. 2018. Geotechnical Engineering Services, American River Common Features Project, Natomas Basin, Reaches A, B, E, F, G, and Riverside Canal, Sacramento and Sutter Counties, CA. August.

———. Wahler and Associates, 1990. Sacramento Urban Area Levee Reconstruction Project, California, Natomas North. July.

Appendix A Geologic Plans and Profiles

Appendix A includes the following information:

A-1 Plan and Profile Index and Legend A-2 Plan and Profile Station 435+00 to Station 445+00 A-3 Plan and Profile Station 445+00 to Station 455+00

§̈¦5

§̈¦5 §̈¦5

§̈¦5

N Bayou Rd

N Bayou Rd

Garden Hwy

Garden Hwy

N Bayou Rd

Garden Hwy

Old River Rd Sacramento River

\\G

IS

D at aD el iv er ab le

\N

AT

S _G

E R

_V 1\

TO

C

_N

AT

S _G

E R

_V 1\

P la te s\

M X

D \N

AT

S

G E

R 1V

1P P

N P

IN

D

E X.

m xd

8.

.2

SA

C

YOLO

NAPA

SOLANO

COLUSA

PLACER

YUBA

SUTTER

SACRAMENTO

NEVADA

EL DORADO

AMADOR

SAN JOAQUIN

BUTTE

CALAVERAS

Davis

Roseville

Sacramento

Placerville

DETAIL AREA

AMERICAN RIVER COMMON FEATURES PROJECT,

NATOMAS BASIN, I-5 WINDOW

Appendix A

Plan and Profile Index and Legend

0 400

Feet 1 inch = 200 feet

Ä.

ML

SC

CL

CH

CH

CL

CL

SM

SP-SM

(*=N60) Blow Count qt 5000Rf,%10

Boring Information

CPT Information

2F -1

7-

G S

E le v.

4.

ft O ffs et

: 1 0.

ft

C P

T-

-0

G S

E le v.

4.

ft O ffs et

: 1 0.

ft

Levee Crown

N(60)ASTM blowcount, blows/foot

USCS Classification

Levee Crown

Friction Ratio, Rf ,%

Corrected Tip Resistance, qt, tsf

Group Names Graphic Graphic Group NamesGraphic Group Names

GROUP SYMBOLS AND NAMES

Lean Clay (CL) Lean Clay with Sand (CL) Fat Clay (CH)

Silty Clay (CL-ML) Silty Clay with Sand (CL-ML) Silt (ML)

Silt with Sand (ML) Sandy Silt (ML) Elastic Silt (MH)

Poorly Graded Sand (SP) Poorly Graded Sand with Clay (SP-SC)

Poorly Graded Sand with Silt

(SP-SM)

Well-Graded Sand with Silt

(SW-SM)

Clayey Sand (SC) Silty Sand (SM)

Poorly Graded Gravel (GP) Well-Graded Gravel with Silt and Sand (GW-GM)

Note: Soils were classified in the field in general accordance with ATM D2488-06, Standard Practice for Description and Identification of Soils (Visual Manual Procedure). Where laboratory testing was performed, classifications were modified in general accordance with ASTM D2487-06, Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System).

Borderline symbols, two group symbols separated by a slash, may be used in field visual classification when (1) percentage of fines is estimated to be between 45% and 55%, (2) percentages of sand and gravel are estimated to be about the same, (3) soil could be either well graded or poorly graded, (4) soil could be either a silt or a clay, or (5) fine-grained soil has properties indicating that it is at the boundary between low and high plasticity.

PLAN LEGEND

!( Levee Mile

Explorations

Ç(# Historic CPT

!A Historic Boring

!ë Hand Auger

Levee Alignment

PROFILE LEGEND

Approximate Elevation of Bottom of Cutoff Wall

Landside Ditch Invert

Landside Levee Toe

Levee Crest

INDEX LEGEND

Levee Alignment

Plan Extent with Plate Number

LM 8.5

Surficial Geology was mapped at 1:20,000.

Surficial Geology

Geologic Units

Water, as mapped from 1937* aerial photographs; date (if shown) indicates year of historical dataset used to map.W

Holocene crevasse splay deposits; fine to coarse sand and silt with clay, with minor lenses of gravel deposited from breaching of natural levees.

Hob

H ol oc en e

Historical overbank deposits; sand, silt, and clay with trace fine gravel, deposited during high-stage water flow that overtopped channel banks.

Rob

H is to ric al

SAMPLER TYPES

Standard Penetration Test

Modified California

Punch Core

Sonic Core

Shelby Tube

Dry Core

Bag Sample

Bulk/Grab Sample

E

LE

VA

TI

O N

, F ee t ( N

AV

D

8) E

LE

VATIO

N , Feet (N

AV

D

88)

Distance, feet

0 25 50 75 100

El ev at io n, fe et

-20

-40

-60

-80

-100

-20

-40

-60

-80

-100

STATIONING, Feet

435+00 436+00 437+00 438+00 439+00 440+00 441+00 442+00 443+00 444+00 445+00

100 100

12* 12***

23*

53*

44*

46*

26*

FILL

ML

SM

ML

SM

SP-SM

SP

SC

SP-SM

SM

CH

CL

SM

CL

CH

CL

CH

CL

MH

CL

8+

R

G S

E le v.

2.

O ffs et : 1

TD Elev. -69.34 ft

Blow Count (* = N60) qt

TD Elev. -42.73 ft

C P

T-

-1

G S

E le v.

7.

O ffs et

Rf,% qt

TD Elev. -43.76 ft

C P

T-

-1

G S

E le v.

6.

O ffs et

Rf,%

SR

E-

- 2

G S

E le v.

7.

O ffs et

TD Elev. -32.82 ft

CONCRETE

SR

E-

- 4

G S

E le v.

8.

O ffs et

TD Elev. -53.33 ft

2F -0

1-

G S

E le v.

7.

O ffs et

TD Elev. -12.75 ft

Blow Count (* = N60)

ASPHALT

ML

SM

ML

SM

ML

SM

SP-SM

SP

SP-SM

SP

Blow Count (* = N60)

SC

SM

CL

SM

CL

SM

SP

SM

ML

SM

SP

SP-SM

SP

CL

Blow Count (* = N60)

SC

CL

SC

CL

SP-SC

ML

SC

CL

ML

SC

CL

SC

CL

SC

CL

SP-SC

2F -0

1-

G S

E le v.

8.

O ffs et

TD Elev. -21.31 ft

Blow Count (* = N60) qt

TD Elev. -53.18 ft

C P

T-

-1

G S

E le v.

1.

O ffs et : 4

.3

Rf,% qt

TD Elev. -50.22 ft

C P

T-

-1

G S

E le v.

1.

O ffs et : 1

.0

Rf,%qt

TD Elev. -66.97 ft

C P

T-

-6

G S

E le v.

1.

O ffs et

1.

Rf,%

SR

E-

- 9

G

S E le v.

0.

O ffs et

.6

TD Elev. -85.96 ft

SR

E-

- 2

G

S E le v.

1.

O ffs et

: 6 .4

TD Elev. -44.96 ft qt

TD Elev. -53.57 ft

C P

T-

-1

G S

E le v.

1.

O ffs et : 8

.5

Rf,%

ASPH

CL

SP

SP-SM

CL

ML

SM

SP-SM

SW-SM

SM

SP-SM

GW-GM

GP

CH

Blow Count (* = N60)

CONC

CEMENT

SP

SM

ML

SM

ML

SP-SM

CH

CL

Blow Count (* = N60)

ASPH

59 ML

CL

ML

G S

E le v.

0.

ft

O ffs et : 6

8.

ft

4F -1

7-

% Fines

TD Elev. 25.33 ft

ML

CL

G S

E le v.

8.

ft

O ffs et : 6

6.

ft

4F -1

7-

% Fines

TD Elev. 23.75 ft

CL-ML

G S

E le v.

3.

ft

O ffs et : 4

8.

ft

4F -1

7-

% Fines

TD Elev. 28.80 ft 73

ML

CL

G S

E le v.

7.

ft

O ffs et : 6

1.

ft

4F -1

7-

% Fines

TD Elev. 22.11 ft

SM

G S

E le v.

1.

ft

O ffs et : 4

6.

ft

4F -1

7-

% Fines

TD Elev. 28.15 ft 41 ML

SM

CL

G S

E le v.

6.

ft

O ffs et : 6

4.

ft

4F -1

7-

% Fines

TD Elev. 21.92 ft

U R

S0

SR

E-

- 5

G S

E le v.

5.

O ffs et

TD Elev. -47.27 ft

SM

CL

CL

ML

SM

ML

SM

SP-SM

CH

CL

Blow Count (* = N60)Rf,% 010

TD Elev. -40.16 ft qt

C P

T-

-1

G S

E le v.

0.

ft

O ffs et : 4

9.

ft

Rf,% 010

TD Elev. -64.44 ft qt

C P

T-

-6

G S

E le v.

2.

ft

O ffs et : 0

.0 ft

LEVEE CREST

LANDSIDE LEVEE

TOE

AMERICAN RIVER COMMON FEATURES PROJECT,

NATOMAS BASIN, REACH B

Appendix A

Plan and Profile

F:

\P ro je ct \U

S A

C E

\N at om as

S up po rt\

I5 _B rid ge

\0 2_

M ap s\

_R ep or t_

M ap s\ I5

B rid ge _P nP .m xd

/1 5/ ti ffa ny .c ar ra sc o-ca b

S A

C

Ç(#

Ç(# Ç(# Ç(#

Ç(#

Ç(# Ç(#

Ç(#

Ç(#

Ç(# Ç(#

Ç(#

!A!A

!A

!A

A

!A

!A

!A

!ë !ë

!ë !ë

!ë

!ë !ë

!ë

2F-01-54

CPT-09-62CPT-09-61

CPT-09-60

SRE-09- 52

CPT-09-63

SRE-09- 28

SRE-08- 90

CPT-09-159

CPT-09-158

CPT-09-156

CPT-09-155

CPT-09-109CPT-09-108CPT-09-107

CPT-09-106

URS071000_438+00R

SRE-09- 29

( 113 feet)

2F-01-55 ( 116 feet)

SRE-09- 48

( 39 feet)

SRE-09- 49

( 198 feet)

SRE-09- 51

( 172 feet)

SRE-09- 50

( 37 feet)

SRE-09- 53

( 180 feet)

4F-17-08

4F-17-074F-17-06

4F-17-05

4F-17-04

4F-17-03

4F-17-024F-17-01

§̈¦5

§̈¦5

8.5

440+00

435+00

445+00

L a n d s i d e

W a t e r s i d e

L

Rob Rob

W 1937

Hob

Hob

Rob

§̈¦5Sacram ento River

Y o l o C o u n t y

S a c r a m e n t o C o u n t y

Station 435+00 to Station 445+00

Ä.Plate Extent

1 inch = 50 feet

0 50

Feet

NOTES:

1. Elevations and locations of levee crown, landside toe, and waterside toe are approximate. These elevations are based on LiDAR data obtained by DWR’s CVFPP (Central Valley Flood Protection Program).

2. Where water was present in the ditch at the time LiDAR was flown, the ditch bottom was estimated.

3. Stick logs represent general soil conditions encountered at the time of exploration. For more detailed information on the materials encountered, refer to boring and CPT logs in the Geotechnical Data Report. No warranty is provided regarding the continuity of soil conditions between individual explorations.

4. When reported, N60 (ASTM), refers to N60 (ASTM) = N field * Hammer Efficiency (%). See Geotechnical Data Report for hammer efficiency data for individual borings.

5. Historical boring locations and profiles are based on available information.

6. USCS classification labels are not presented on the profiles for soil lenses (thickness less than 1.5 feet).

7. The information provided in these plans and stick-log plates has been compiled…