April 12, 2023
Arik Bord
ECORP Consulting, Inc.
Via Email to: [email protected]
Re: Manteca Well 29,2023-051.01 Project, San Joaquin County Dear Mr. Bord:
A record search of the Native American Heritage Commission (NAHC) Sacred Lands File (SLF) was completed for the information you have submitted for the above referenced project. The results were negative. However, the absence of specific site information in the SLF does not indicate the absence of cultural resources in any project area. Other sources of cultural resources should also be contacted for information regarding known and recorded sites.
Attached is a list of Native American tribes who may also have knowledge of cultural resources in the project area. This list should provide a starting place in locating areas of potential adverse impact within the proposed project area. I suggest you contact all of those indicated; if they cannot supply information, they might recommend others with specific knowledge. By contacting all those listed, your organization will be better able to respond to claims of failure to consult with the appropriate tribe. If a response has not been received within two weeks of notification, the Commission requests that you follow-up with a telephone call or email to ensure that the project information has been received.
If you receive notification of change of addresses and phone numbers from tribes, please notify me. With your assistance, we can assure that our lists contain current information.
If you have any questions or need additional information, please contact me at my email address: [email protected].
Sincerely,
Pricilla Torres-Fuentes
Cultural Resources Analyst
Attachment
STATE OF CALIFORNIA
April 12, 2023
Arik Bord
ECORP Consulting, Inc.
CHAIRPERSON
Laura Miranda
Luiseño
VICE CHAIRPERSON
Reginald Pagaling
Chumash
SECRETARY
Sara Dutschke
Miwok
COMMISSIONER
Isaac Bojorquez
Ohlone-Costanoan
COMMISSIONER
Buffy McQuillen
Yokayo Pomo, Yuki,
Nomlaki
COMMISSIONER
Wayne Nelson
Luiseño
COMMISSIONER
Stanley Rodriguez
Kumeyaay
COMMISSIONER
[VAVANT]
COMMISSIONER
[VACANT]
EXECUTIVE SECRETARY
Raymond C.
Hitchcock
Miwok/Nisenan
NAHC HEADQUARTERS
1550 Harbor Boulevard
Suite 100
West Sacramento,
California 95691
(916) 373-3710
[email protected]
NAHC.ca.gov
ATTACHMENT 3
Buena Vista Rancheria of MeWuk Indians
Rhonda Morningstar Pope,
Chairperson
1418 20th Street, Suite 200
Sacramento, CA, 95811
Phone: (916) 491 - 0011
Fax: (916) 491-0012
[email protected]
Me-Wuk
California Valley Miwok Tribe
AKA Sheep Rancheria of Me-Wuk
Indians of CA,
P.O. Box 395
West Point, CA, 95255
Phone: (209) 293 - 4179
[email protected]
Miwok
California Valley Miwok Tribe
14807 Avenida Central
La Grange, CA, 95329
Phone: (209) 931 - 4567
Fax: (209) 931-4333
Miwok
Ione Band of Miwok Indians
Sara Dutschke, Chairperson
9252 Bush Street
Plymouth, CA, 95669
Phone: (209) 245 - 5800
[email protected]
Miwok
Muwekma Ohlone Indian Tribe
of the SF Bay Area
Monica Arellano, Vice
Chairwoman
20885 Redwood Road, Suite 232
Castro Valley, CA, 94546
Phone: (408) 205 - 9714
[email protected]
Costanoan
North Valley Yokuts Tribe
Timothy Perez,
P.O. Box 717
Linden, CA, 95236
Phone: (209) 662 - 2788
[email protected]
Costanoan
Northern Valley
Yokut
North Valley Yokuts Tribe
Katherine Perez, Chairperson
P.O. Box 717
Linden, CA, 95236
Phone: (209) 887 - 3415
[email protected]
Costanoan
Northern Valley
Yokut
Tule River Indian Tribe
Kerri Vera, Environmental
Department
P. O. Box 589
Porterville, CA, 93258
Phone: (559) 783 - 8892
Fax: (559) 783-8932
[email protected]
Yokut
Tule River Indian Tribe
Joey Garfield, Tribal Archaeologist
P. O. Box 589
Porterville, CA, 93258
Phone: (559) 783 - 8892
Fax: (559) 783-8932
joey.garfield@tulerivertribensn.gov
Yokut
Tule River Indian Tribe
Neil Peyron, Chairperson
P.O. Box 589
Porterville, CA, 93258
Phone: (559) 781 - 4271
Fax: (559) 781-4610
[email protected]
Yokut
Wilton Rancheria
Jesus Tarango, Chairperson
9728 Kent Street
Elk Grove, CA, 95624
Phone: (916) 683 - 6000
Fax: (916) 683-6015
[email protected]
Miwok
Wilton Rancheria
Dahlton Brown, Director of
Administration
9728 Kent Street
Elk Grove, CA, 95624
Phone: (916) 683 - 6000
[email protected]
Miwok
1 of 2
This list is current only as of the date of this document. Distribution of this list does not relieve any person of statutory responsibility as defined in Section 7050.5 of the Health and Safety Code, Section 5097.94 of the Public Resource Section 5097.98 of the Public Resources Code.
This list is only applicable for contacting local Native Americans with regard to cultural resources assessment for the proposed Manteca Well 29, 2023-051.01 Project, San Joaquin County.
PROJ-2023-
001914
04/12/2023 02:02 PM
Native American Heritage Commission
Native American Contact List
San Joaquin County
4/12/2023
ATTACHMENT 3
Wilton Rancheria
Steven Hutchason, THPO
9728 Kent Street
Elk Grove, CA, 95624
Phone: (916) 683 - 6000
Fax: (916) 863-6015
shutchason@wiltonrancheriansn.gov
Miwok
Wuksache Indian Tribe/Eshom
Valley Band
Kenneth Woodrow, Chairperson
1179 Rock Haven Ct.
Salinas, CA, 93906
Phone: (831) 443 - 9702
[email protected]
Foothill Yokut
Mono
Confederated Villages of Lisjan
Nation
Corrina Gould, Chairperson
10926 Edes Avenue
Oakland, CA, 94603
Phone: (510) 575 - 8408
[email protected]
Bay Miwok
Ohlone
Delta Yokut
Confederated Villages of Lisjan
Nation
Deja Gould, Language Program
Manager
10926 Edes Ave
Oakland, CA, 94603
Phone: (510) 575 - 8408
[email protected]
Bay Miwok
Ohlone
Delta Yokut
Confederated Villages of Lisjan
Nation
Cheyenne Gould, Tribal Cultural
Resource Manager
10926 Edes Ave
Oakland, CA, 94603
Phone: (510) 575 - 8408
[email protected]
Bay Miwok
Ohlone
Delta Yokut
2 of 2
This list is current only as of the date of this document. Distribution of this list does not relieve any person of statutory responsibility as defined in Section 7050.5 of the Health and Safety Code, Section 5097.94 of the Public Resource Section 5097.98 of the Public Resources Code.
This list is only applicable for contacting local Native Americans with regard to cultural resources assessment for the proposed Manteca Well 29, 2023-051.01 Project, San Joaquin County.
PROJ-2023-
001914
04/12/2023 02:02 PM
Native American Heritage Commission
Native American Contact List
San Joaquin County
4/12/2023
ATTACHMENT 3
Draft Initial Study/Mitigated Negative Declaration
APPENDIX D
Total Construction-Related Gasoline Usage
ECORP Consulting, Inc. 2023
ATTACHMENT 3
Proposed Project
Total Construction-Related Gasoline Usage
Action Carbon Dioxide Equivalents (CO2e) in Metric Tons1 Conversion of Metric Tons to Kilograms2 Construction Equipment Emission Factor2 Total Gallons Consumed During Construction Year One: 5,517 Sources:
1 ECORP Consulting. 2022. Air Quality and Greenhouse Gas Emissions Assessment: Well 29 TCP Treatment Project 2 Climate Registry. 2016. General Reporting Protocol for the Voluntary Reporting Program version 2.1. January 2016. http://www.theclimateregistry.org/wp-content/uploads/2014/11/General-Reporting-Protocol-Version-2.1.pdf Project Construction 056 56,000 10.15
Table 1. Construction Year One
Construction
ATTACHMENT 3
Draft Initial Study/Mitigated Negative Declaration
APPENDIX E
Geotechnical Report
Blackburn Consulting, 2023
ATTACHMENT 3
Prepared for:
10569 Old Placerville Road
Sacramento, CA 95827
Prepared by:
11521 Blocker Drive, Ste 110.
Auburn, CA 95603
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP
Treatment Project
Manteca, CA
August 2023
ATTACHMENT 3
Auburn Office:
11521 Blocker Drive, Ste 110
Auburn, CA 95603 Fresno (530) 887-1494
(530) 887-1494 West Sacramento (916) 375-8706
August 2, 2023
File No. 4228.003X
HydroScience Engineers
Mr. Bill Slenter, PE
10569 Old Placerville Road
Sacramento, CA 95827
[email protected]
Subject: GEOTECHNICAL REPORT, REV 2
City of Manteca Well 29 TCP Treatment Project
Manteca, California
Dear Mike,
Blackburn Consulting (Blackburn) is pleased to submit this Geotechnical Report for the City of Manteca’s Well 29 TCP Treatment Project in Manteca, California. We prepared this report based on our November 9, 2022, proposal. Our report contains a summary of subsurface conditions and geotechnical design/construction recommendations. This revised report includes updated seismic design parameters based on updated risk category provided by HydroScience Engineers.
Thank you for selecting Blackburn to be on your design team. Please call if you have questions or require additional information.
Sincerely,
BLACKBURN CONSULTING
Robert C. Pickard, PG, CEG Haze M. Rodgers, PE, GE
Project Manager Director of Geotechnical Services
Copies: Kennedy/Jenks Consultants, Inc. (PDF)
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
i
Table of Contents
1 INTRODUCTION.....................................................................................................................................1 Purpose .........................................................................................................................................1 Scope of Services...........................................................................................................................1 Site and Project Description..........................................................................................................1 2 SITE GEOLOGY AND SUBSURFACE CONDITIONS...................................................................................3 Site Geology ..................................................................................................................................3 Faulting..........................................................................................................................................3 Exploratory Borings and Soil Conditions.......................................................................................3 Groundwater................................................................................................................................. 4 3 LABORATORY TESTS ..............................................................................................................................4 4 CONCLUSIONS AND RECOMMENDATIONS...........................................................................................5 2022 California Building Code Seismic Parameters......................................................................5 Liquefaction Evaluation.................................................................................................................6 Seismic Settlement Evaluation......................................................................................................6 Settlement Evaluation...................................................................................................................7 Grading..........................................................................................................................................7 Excavations............................................................................................................................7 Original Ground and Subgrade Preparation, and Loose Soil Mitigation...............................8 Fill and Compaction...............................................................................................................9 Over-optimum Soil Moisture ................................................................................................9 Utility Trenches...........................................................................................................................10 Trench Excavation Stability .................................................................................................10 Trench Dewatering..............................................................................................................10 Backfill.................................................................................................................................10 Shallow Mat Foundations...........................................................................................................10 Concrete Pavement.....................................................................................................................11 Concrete Flatwork.......................................................................................................................12 Soil Corrosivity ............................................................................................................................12 5 RISK MANAGEMENT............................................................................................................................12 6 LIMITATIONS .......................................................................................................................................13 ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
ii
CONTENTS (cont.)
FIGURES
Figure 1: Vicinity Map
Figure 2: Site Plan
APPENDIX A
Boring Log Legend Boring Logs
APPENDIX B
Laboratory Test Results
APPENDIX C
Important Information about This Geotechnical Engineering Report, Geoprofessional Business Association, 2019
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
1 1 INTRODUCTION
Purpose
Blackburn Consulting prepared this geotechnical report for design and construction of the City of Manteca’s Well 29 TCP Treatment Project in Manteca, California (Project). Our report contains a summary of the surface and subsurface conditions encountered and geotechnical design/construction recommendations.
Blackburn prepared this report for HydroScience Engineers (HydroScience) and the City of Manteca for design and construction of the project. Do not use or rely upon the report for different locations or improvements without Blackburn’s written consent.
Scope of Services
To prepare this report, Blackburn:
• Discussed the project with Bill Slenter, PE and Austin Poulson with HydroScience. • Reviewed the project plans1 provided by HydroScience. • Observed the subsurface conditions in 2 borings drilled in the vicinity of the proposed improvements on March 9, 2023.
• Performed laboratory tests on soil samples obtained from the exploratory borings.
Site and Project Description
The project site is located east of El Portal Avenue on the west side of Yosemite Park adjacent to the existing Well 29 in Manteca, California. The approximate site location on Figure 1 - Vicinity Map. The project includes construction of six 12-foot diameter GAC treatment vessels supported by an at grade reinforced mat foundation and associated piping. Two tank locations are being considered. The primary tank site is the existing concrete basketball court north of Well 29. The alternate tank site is in the irrigated lawn east of Well 29. A reinforced concrete access road is planned from El Portal to the north side of the primary tank site. Photos 1 and 2 below show surface conditions during our subsurface exploration. 1 Figure A, Well 29 GAC Treatment Plan by HydroScience; Survey Boundary, Well 29 GAC Treatment Plan by HydroScience emailed March 14, 2023; Drinking Water Treatment System Moderl 12 DWC, Cone, 8” Piping General Arrangement, November 15, 2022 by CalgonCarbon
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
2 Photo 1: Primary tank site looking southwest. Well 29 located in block building.
Photo 2: Alternative tank site looking south. Existing Well 29 is located on the right of photo.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
3 We understand that significant grading is not anticipated and limited to minor cuts and fills. Figure 2 displays the site and proposed project improvements.
2 SITE GEOLOGY AND SUBSURFACE CONDITIONS
Site Geology
The project site is located in the Great Valley Geomorphic Province. The Great Valley Province includes the Sacramento and San Joaquin Valleys and is bound by the Sierra Nevada on the east and the Coast Ranges on the west.
The relatively flat surface of the Sacramento Valley is underlain by alluvial, lacustrine, and marine sedimentary deposits that have accumulated as the structural trough (Great Valley) formed and the adjacent mountain ranges were elevated. The thickness of the sediments varies from a thin veneer along the valley margins to thousands of feet at the axis of the trough. The main axis of the trough is oriented north-south along the valley’s main drainage (over 20 miles east of the site).
We reviewed published mapping2 and observed the site is underlain by Quaternary dune sand.
Faulting
The Fault Activity Map of California (Jennings and Bryant, 2010)3 and the Geologic Map of the Sacramento Quadrangle (Wagner et al., 1981) do not identity Historic or Holocene age faults (displacement within the last 11,700 years) within or adjacent to the site. Faults with Historic or Holocene (last 11,700 years) rupture are often considered "active." The closest mapped fault to the site is the Quaternary Vernalis fault located approximately 6.8 miles southwest of the site.
The site does not lie within or adjacent to an Alquist–Priolo Earthquake Fault Zone (Bryant and Hart, 2007).4 Exploratory Borings and Soil Conditions
To explore the subsurface conditions, Blackburn’s drilling subcontractor, Taber Drilling (Taber), drilled two borings (B-23-1 and B-23-2) on March 9, 2023, to depths ranging from 11.5 to 51.5 feet below existing ground surface (bgs). Blackburn’s engineer, Luke Morrell, PE, observed the borings. Figure 2 shows the approximate boring locations.
Taber drilled the borings using 4 to 6-inch diameter solid stem augers above the groundwater and mud rotary below the groundwater. Luke obtained soil samples at various intervals using both 3.0-inch.
O.D. Modified California samplers (equipped with 2.4-inch diameter brass liners) and 2–inch O.D. 2 “Geologic Map of the San Francisco-San Jose Quadrangle, California”; Regional Geologic Map Series; Map No. 5A; California Division of Mines and Geology; D.L. Wagner, E.J. Bortugno, R.D. McJunkin, 1991. 3 Jennings, C.W., and Bryant, W.A., 2010, Fault Activity Map of California, California Geological Survey, California Geologic Data Map Series, Map No. 6.
4 Bryant, W.A., and Hart, E.W., 2007 (Interim Revision), Fault-Rupture Hazard Zones in California: California Department of Conservation, Division of Mines and Geology, Special Publication 42.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
4 Standard Penetration (SPT) samplers. Taber used a safety semi-automatic hammer, weighing 140- pounds and falling approximately 30-inches per blow, to drive samplers. Luke also collected bulk samples at various depths within the borings. Luke transported the samples to our lab for testing.
Taber backfilled the holes with neat cement grout. A representative from San Joaquin County’s Department of Environmental Health observed Taber backfill boring BC-23-1.
We encountered approximately 4 feet of loose silty sandy overlying interbedded layers of medium dense silty sands and sands, and very stiff to hard silt and clay with varying amounts of sand to 51.5 feet (maximum depth explored). Refer to our boring logs (Appendix A) for more specific subsurface conditions.
Groundwater
We observed groundwater in borehole BC-23-1 at approximately 23 feet bgs during drilling (approximate elevation 10 feet5
). Taber continued drilling BC-23-1 using the mud-rotary method. We did not observe groundwater in boreholes BC-23-2.
We reviewed groundwater level data available at the California Department of Water Resources website (https://gis.water.ca.gov/app/gicima/). Seasonal groundwater depths range from about 20 to 30 feet below existing grade (approximate elevation 3 to 13 feet5) near the site.
Groundwater and perched water levels can fluctuate due to changes in precipitation, waterway levels , irrigation, pumping of wells, and other factors.
3 LABORATORY TESTS
We performed lab tests on representative soil samples taken from the exploratory borings for:
• Unit weight and moisture content tests for in-situ soil consistency determination. • #200 wash sieve analysis for soil classification.
• Plasticity index for soil classification and soil expansion potential. • Soil corrosivity (pH, resistivity, sulfate, and chlorides) for soil corrosion characteristics. • Direct shear test for soil strength.
We present laboratory test results in Appendix B and include the unit weight, moisture content on the boring logs in Appendix A.
5 Elevation estimated based on USGS 7.5’ Topographic Map, Manteca, 1952, revised 1994, vertical datum National Geodetic Vertical Datum of 1929.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
5 4 CONCLUSIONS AND RECOMMENDATIONS
2022 California Building Code Seismic Parameters
Blackburn used the SEAOC/OSHPD Seismic Design Maps Tool to determine our recommended 2022 California Building Code (CBC) seismic design parameters are considered:
• ASCE 7-16 Reference Standard
• Risk Category IV
• Site Class D – Stiff Soil
• Latitude: 37.792726 Longitude: -121.232613
• Structure meets one or more of the exceptions identified in ASCE 7-16 Section 11.4.8.
These inputs were selected based on the subsurface conditions encountered near the pump station.
Table 4 presents our recommended 2019 CBC seismic design parameters. * Blackburn calculated values assuming the exception for a ground motion hazard analysis per ASCE 7- 16, 11.4.8.
** Recommended SM1 and SD1 values are increased by 50% from mapped values in accordance with ASCE 7-16 Supplement 3 Section 11.4.8 Exception.
Blackburn should be notified if the assumptions listed above are incorrect. Blackburn should perform a sitespecific response analysis for final design if the proposed design does not meet the exception noted above.
Table 4: 2022 CBC Seismic Design Parameters
Ss – Acceleration Parameter 0.798
S1 – Acceleration Parameter 0.301
Fa – Site Coefficient 1.2
Fv – Site Coefficient 1.999*
SMS – Adjusted MCE Spectral Response Acceleration Parameter 0.958 SM1 – Adjusted MCE Spectral Response Acceleration Parameter 0.903* SDS – Design Spectral Response Acceleration Parameter 0.638 SD1 – Design Spectral Response Acceleration Parameter 0.602* PGA 0.333
PGAM- MCE PGA adjusted for site effects 0.421
TL – Long Period Transition Period 8
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
6 Liquefaction Evaluation
Soil liquefaction can occur when saturated, relatively loose sand and low-plasticity soft fine-grained saturated soil are subject to ground shaking strong enough to generate adequate excess pore pressure to separate soil particles. This separation and subsequent pore pressure dissipation can lead to decreased soil shear strength and settlement.
The liquefaction susceptibility of a soil deposit is a function of the soil grain size, relative density, percent fines (clay and silt), plasticity of the fines, degree of saturation, age of deposit, and earthquake ground motion. Blackburn used the simplified procedure outlined by Youd et al. (2001)6 to evaluate the potential for soil liquefaction to occur at the site.
Blackburn performed a probabilistic seismic–hazard deaggregation using the USGS Unified Hazard web tool (https://earthquake.usgs.gov/hazards/interactive/) to evaluate the site-to-fault distance and Maximum Moment Magnitude (Mmax) of earthquake scenarios that have significant contributions to the projects seismic hazard for our liquefaction evaluation. The deaggregated results for the PGA show site-to-fault distances ranging from approximately 16 to 24 miles and earthquake magnitudes ranging from 6.46 to 7.16 have significant contributions to the sites seismic hazard. We evaluated the various combinations of fault distance and earthquake magnitude for our liquefaction evaluation. We used a Peak Ground Acceleration (PGAM) of 0.421 g for the site and a ground water depth of 20 feet (approximate elevation of 14 feet), to represent anticipated high ground water levels at the site.
Using the above parameters, Blackburn evaluated liquefaction potential at the site using the subsurface data for Boring BC-23-1. Our evaluation indicates that the medium dense poorly graded sand at a depth of 33.5 to 43.5 feet and the very stiff lean clay at 43.5 to 48.5 feet is potentially liquefiable (safety factor not greater than 1.0).
Seismic Settlement Evaluation
Blackburn used methods outlined by Idriss and Boulanger (2008) 7 to estimate post-liquefaction
settlement. The method follows the approach developed by Ishihara and Yoshimine (1992) that relates volumetric strain, SPT (N1)60cs, and the factor of safety against liquefaction to estimate the postliquefaction settlement of a liquefied layer.
Our analysis of Boring BC-21-1 data yielded a total potential post-liquefaction settlement of about 1.2 inches within the liquefiable layers of soil from 33.5 to 48.5 feet below existing grade. However, the actual amount of settlement at the surface from these layers will be less due the thickness and strength of the overlying soil layers.
6 Youd, T. L., et al, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 127, No. 10, October 2001, pp. 817-833. 7 Idriss, I. M. and Boulanger, R. W., "Soil Liquefaction During Earthquakes," Earthquake Engineering Research Institute, pages 140-142 and 152-158, 2008.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
7 We used Pradel’s8 method to estimate settlement in dry sand to evaluate settlement of sand layers overlying the saturated soils. Our analysis shows that the sands overlying the groundwater may settle approximately 0.15 inches during the design earthquake.
Settlement Evaluation
Blackburn used RocScience Settle3 software and soil data from boring BC-23-1 to evaluate immediate settlement and long-term consolidation. To develop our model, we used the following parameters:
• Loading:
o Assumed 2-foot-thick mat thickness (pressure = 300 psf). o Six 12 foot diameter circular tanks distributed.
o Tank Pressure of 800 psf.
• Soil Parameters:
o For immediate settlement we determined modulus values Es based on published values and SPT correlation equations from Bowles9 and FHWA10.
o For consolidation settlement we determined consolidation parameters (Cc, Cr, void ratio, and OCR) from published values and SPT correlations 1112.
To limit immediate settlement of the upper 4 feet of loose sands over-excavate and recompact the soil within the footprint of the concrete mat foundation supporting the GAC tanks to a depth of 2.5 feet below the bottom of the foundations (approximately 4 feet below existing grade). Our Settle3 analysis shows immediate settlement of approximately 1 inch will occur within approximately the first year after construction and longterm consolidation settlement of approximately 0.25 inches will occur over subsequent years. We expect differential settlement of approximately 0.5 inches across the length of the mat foundation.
Grading
Where referenced in this report, use ASTM D 1557 test method to determine relative compaction and optimum moisture. Compacted soil is not suitable (even if it meets relative compaction requirements) if it is unstable and pumps or flexes excessively under construction equipment loads.
Excavations
The soil encountered in our explorations should be excavatable with conventional earthmoving equipment (e.g., scrapers, dozers, backhoes, and hydraulic excavators) to typical excavation depths. 8 Pradel, D, “Procedure to Evaluate Earthquake-Induced Settlements in Dry Sand, Journal of Geotechnical and Geoenvironmental Engineering”, April 1998
9 Bowles, J.E., “Foundation Analysls and Design”, 5th Edition, 1997 10 FHWA, “Soil and Foundations – Volume 1, Table 5-16” December 2006 11 Koppula, D.D., “Statistical estimation of compression index”, Geotechnical Testing Journal, Vol 4, Iss: 2, May 31, 1981
12 Kulhawy, F.H. and Mayne, P.W., “Manual for Estimating Soil Properties for Foundation Design”, EPRI EL-6800, 1990.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
8 On a preliminary basis, use temporary excavation sloping and shoring for Type C soil (Federal Register, 29 CFR, Part 1926, Subpart P; Occupational Safety and Health Standards – Excavations). We base this soil type on the hard fine-grained soils and medium dense to dense granular soils encountered in our borings. For Type C soil conditions, temporary excavations may be sloped at 1.5(H) to 1(V). Even with proper sloping, some sloughing of side slopes may occur.
All excavations must be sloped, shored, and/or shielded in accordance with current Cal/OSHA requirements. The contractor is responsible for site safety, final excavation and shoring design (including OSHA soil type determination) and construction, based on actual excavation conditions (including trench spoils, equipment, stockpiles, etc.) encountered during construction. The contractor is also responsible for the protection of existing facilities and improvements. At the time of construction, the contractor must evaluate and adjust accordingly excavation sloping/shoring methods based on:
• The impact of construction traffic vibrations.
• Actual soil conditions exposed in the open excavations. • Seepage and/or groundwater conditions.
• Surcharges adjacent to excavations.
• Proximity of excavations to existing structures.
• Other factors that may promote excavation wall instability or cause excavation related damage to existing facilities and improvements.
Original Ground and Subgrade Preparation, and Loose Soil Mitigation Prior to site grading, remove vegetation, debris, abandoned utilities, soft or unstable areas, or other deleterious materials.
Strip the site to a depth of approximately 2 inches to remove surface vegetation and associated organics where present. Do not use strippings to fill in building, pavement, or other structural areas. Consult the landscape architect to determine if strippings are acceptable for use as fill in landscape areas.
Over-excavate and recompact the soil within the footprint of the concrete mat foundation supporting the GAC tanks to a depth of 2.5 feet below the bottom of the foundations (approximately 4 feet below existing grade). The over-excavation and recompaction should extend at least 5 feet laterally beyond the edge of the foundations except for the south side of the pad where existing facilities will not make this possible.
Excavation sides may need to be sloped due to lose sand sloughing in approximately the upper 4 feet of excavations. Sloughed soil should be removed and/or recompacted. Scarify and compact the exposed subgrade at the bottom of the over-excavated area as recommended below. Soil that sloughs into excavations should be removed prior to subgrade preparation and foundation construction. Sloughed soil can be incorporated into fill layers provided the layers below have been compacted adequately and the resulting fill thickness can be compacted. Place and compact fill in accordance with Section 4.4.4 of this report.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
9 Process and compact the exposed native subgrade as follow:
1. Scarify the subgrade to a depth of 8 inches.
2. Moisture conditions the scarified soil to 1% to 3% above the optimum moisture content.
3. Compact scarified subgrade to a minimum of 90% relative compaction based on ASTM D 1557 test procedure.
Blackburn must observe all excavations prior to backfill placement to verify that competent bearing materials have been exposed.
Fill and Compaction
The on-site soil may be used as fill provided it is free of debris and visible concentrations of vegetation and has a maximum particle size of 4 inches. Refer to Section 4.4.3 for restrictions on using on-site strippings as fill.
Imported fill must meet the following requirements:
• No concentrations of organics, debris, and other deleterious materials, • Maximum particle size of 1-inch, with at least 50 percent passing the No. 4 Sieve and at least 20 percent passing the No. 200 Sieve, and
• Expansion index less than 25, per ASTM D4829.
Place and compact on-site soil and imported fill as follows:
1. Place fill in loose lifts no thicker than 8 inches prior to compaction.
2. Moisture condition fill to –1% to 2% above the optimum moisture content.
3. Compact fill to at least 95% relative compaction within mat foundation excavation (mat plus 5 feet beyond edge see Section 4.4.3) , and within the upper 12-inches of concrete pavement subgrade.
4. Compact all other fill to at least 90% relative compaction.
CLSM may also be used as backfill. CLSM must meet the requirements of Section 19-3.02G (Controlled Low-Strength Material) of the 2015 Caltrans Standard Specifications, except the 28-day compressive strength shall be between 50 psi and 200 psi.
Over-optimum Soil Moisture
Over-optimum (wet) soil conditions can make proper compaction difficult or impossible. Wet soil is commonly encountered during the winter and spring months, in excavations where groundwater or perched ground water is encountered, or at any time of year within and adjacent to landscape areas or beneath existing pavement.
In general, wet soil can be mitigated by:
• Discing the soil during prolonged periods of dry weather, • Remove and replacement with drier material,
• Lime or cement treatment or stabilization using aggregate and stabilization fabric or grid.
If wet, unstable soil is encountered, retain Blackburn to observe the conditions and provide specific mitigation recommendations.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
10 Utility Trenches
Trench Excavation Stability
Vertical trenches in the loose silty sands identified in the upper 4 feet may not be stable and sloughing of excavation side slopes may occur. The contractor is responsible for the selection, design, and installation of necessary shoring. Refer to Section 4.4.1 for excavation sloping and shoring considerations. Soil that sloughs into excavations should be removed prior to subgrade preparation and foundation construction. Sloughed soil can be incorporated into fill layers provided the layers below have been compacted adequately and the resulting fill thickness can be compacted.
Trench Dewatering
We do not anticipate that open cut trenches will encounter the static groundwater table. Perched ground water could be encountered in excavations during the winter and spring months. In general, we anticipate that sump pumps can be used to dewater open cut trench excavations if perched water is encountered.
Backfill
On-site native soil can be used as trench backfill outside the pipe bedding and pipe zone limits provided it is free of significant concentrations of organics, debris, and other deleterious materials. Trench backfill and/or CLSM must meet the requirements of Section 4.4.4.
Place trench backfill in maximum 12-inch thick loose lifts, moisture condition at 1% to 2% above the optimum moisture content. City of Manteca Standards specify the upper 2.5 feet of trench backfill be compacted to 95% relative compaction. Trench backfill below the upper 2.5 feet is to compacted to 90% relative compaction. Jetting is not acceptable for compaction.
Soil excavated during trenching may have a moisture content well over optimum, especially during the winter and spring months, within or adjacent to landscape areas, beneath pavements or if perched water is encountered. In this case, it will be necessary to dry back the soil prior to use as backfill.
Although we do not anticipate soft unsuitable pipe foundation subgrade at any location, notify the project engineer and Blackburn to review conditions and provide specific mitigation recommendations if encountered. Typical mitigation may include replacement of unsuitable subgrade with ¾-inch minus crushed rock (6-12 inches thick), enclosed in geotextile filtration fabric to achieve a stable and nonyielding subgrade suitable for pipe placement and backfilling.
Shallow Mat Foundations
Provided our site grading recommendations (Section 4.4) are performed a stiffened mat foundation is suitable to support the proposed GAC tanks.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
11 • Embed the mat foundations a minimum of 18 inches below the surface on the engineered fill as specified in section 4.4.3 and 4.4.4.
• Size the mat not to exceed an allowable bearing pressure of 1,100 pounds per square foot (psf).
This value may be increased by one-third for transient loads with the alternative basic load combinations in Section 1605.2 (2022 CBC) that include wind or seismic loads. • Considering a uniform bearing pressure, use a Modulus of Subgrade Reaction, ks, of 7 kips per cubic foot (kcf) in the center of the mat, 8 kcf along the mat edge, 11 kcf at the mat corners, and 15 kcf below the tanks. The load-deformation (settlement) behavior of soil is non-linear and complex. Blackburn should review preliminary estimated bearing pressures and settlements from the structural calculations of the mat to confirm the values are consistent with the geotechnical calculations and subgrade moduli’ provided. Blackburn will provide updated subgrade moduli if values are significantly different. • For mat foundations designed in accordance with the recommendations above, we estimate total immediate settlement of approximately 1 inch and differential settlement of approximately 1/2-inch across the length of the mat foundation. We expect an additional long-term consolidation settlement of 0.25 inches.
• To resist lateral movement, use a coefficient of friction of 0.40 and ultimate passive earth pressure of 340 psf per foot of depth. The allowable passive earth pressure can be increased by one-third for transient loads where used with the alternative basic load combinations in Section 1605.2 (2022 CBC) that include wind or seismic loads. • Clean excavations of debris and loose soil prior to placing concrete. • Slope the ground surface away from the mat foundations at a minimum of 2 percent for a distance of at least 5 feet.
• Blackburn must observe all excavations prior to reinforcement placement to verify that competent bearing materials have been exposed.
Concrete Pavement
Considering the subsurface conditions encountered in the borings and the anticipated size/weight of the proposed trucks we recommend the subgrade beneath the access road be prepared in accordance with Section 4.4.3 and 4.4.4. Design the access road concrete pavement in accordance with ACI 330R-08.
Use a Subgrade Reaction, ks, of 180 pounds per cubic inch.
We recommend a minimum concrete pavement section of 7.0 inches of concrete over a minimum 6.0 inches of Class 2 Aggregate Base. The concrete should have a minimum 28-day compressive strength of 4,000 psi.
AB should conform to Caltrans Class 2 requirements. Moisture condition and compact AB to a minimum 95% relative compaction. Prior to placing concrete, the aggregate base should be stable under the weight of a loaded water truck. Mitigate unstable areas as recommended by Blackburn.
Construct steel reinforcement and joints in accordance with ACI 330R-08 guidelines to help control shrinkage cracking.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
12 Concrete Flatwork
Exterior flatwork for pedestrian traffic only such as sidewalks and patios may be placed directly on the prepared subgrade without rock underlayment. The subgrade should be free of debris, uniformly compacted to 90% ASTM D1557 before the concrete is placed. Flatwork must be properly jointed to allow for slab shrinkage and movement. ACI provides recommendations on slab jointing based on slab thickness, location, and use.
Soil Corrosivity
Table 2 presents the soil corrosivity test results.
Table 2: Soil Corrosivity Test Results
Boring
No.
Sample
No.
Depth
(ft.) pH
Minimum
Resistivity
(ohm-cm)
Chloride
Content
(ppm)
Sulfate
Content
(ppm)
BC-23-1 1B 2.0-2.5 7.70 4,820 3.7 0.8
Based on the above test results, structural concrete in contact with the ground should meet the concrete and reinforcing steel requirements of the American Concrete Institute’s Building Code Requirements for Structural Concrete (ACI 318-14) for exposure class S0 (sulfates) and exposure class C1 (chlorides).
The above test results indicate that the soil at the site is corrosive to steel and other metals. We are not corrosion consultants and cannot evaluate the potential corrosion impacts to metallic elements embedded in or in contact with the ground. Retain a corrosion consultant to provide specific corrosion protection recommendations if buried metallic elements are used at the site. 5 RISK MANAGEMENT
Our experience and that of our profession clearly indicates that the risks of costly design, construction, and maintenance problems can be significantly lowered by retaining the geotechnical engineer of record to provide additional services during design and construction. For this project, retain Blackburn to:
• Review preliminary structural calculations for the mat to confirm the estimated bearing pressures and settlement are consistent with the geotechnical conditions. If calculated bearing pressure and estimated settlements are significantly different, Blackburn will provide updated recommended subgrade moduli.
• Review and provide comments on the civil and structural plans and specifications prior to construction. • Attend a preconstruction meeting with the owner, general contractor, earthwork contractor and underground contractor prior to site clearing, grubbing and demolition of existing structures to review geotechnical recommendations, testing requirements and project schedule. • Observe removal of underground utilities, foundations, vegetation (root balls and roots) and other underground features in accordance with the project plans, specifications and this Geotechnical Report including loose soil generated from the removal.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 2
City of Manteca - Well 29 TCP Treatment Project
August 2, 2023
13 • Monitor construction to check and document our report assumptions. At a minimum, Blackburn should monitor (and tests were applicable) bottom of excavations beneath tank pad and access road, fill placement and compaction, foundation excavations, and pavement subgrade and aggregate base compaction.
• Update this report if design changes occur, 2 years or more elapses between this report and construction, and/or site conditions have changed.
If we are not retained to perform the above applicable services, we are not responsible for any other party’s interpretation of our report, and subsequent addendums, letters, and discussions. 6 LIMITATIONS
Blackburn performed services in accordance with generally accepted geotechnical engineering principles and practices currently used in this area. Where referenced, we used ASTM or Caltrans standards as a general (not strict) guideline only. We do not warranty our services.
Blackburn based this report on the current site conditions. We assume the soil and groundwater conditions encountered in our borings are representative of the subsurface conditions across the site.
Actual conditions between these locations could be different.
Our scope did not include evaluation of on-site hazardous material, flood potential, aerial photograph review, or biological pollutants. Please contact Blackburn if you would like an evaluation of one or more of these potential issues.
Appendix A presents our exploratory boring logs. The lines designating the interface between soil types are approximate. The transition between soil types may be abrupt or gradual. Our recommendations are based on the final logs, which represent our interpretation of the field logs, laboratory test results, and general knowledge of the site and geological conditions.
Refer to Appendix C (Important Information about This Geotechnical Engineering Report, Geoprofessional Business Association, 2019) for additional limitations regarding this report.
Modern design and construction is complex, with many regulatory sources/restrictions, involved parties, construction alternatives, etc. It is common to experience changes and delays. The owner should set aside a reasonable contingency fund based on complexities and cost estimates to cover changes and delays.
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 1
City of Manteca - Well 29 TCP
Treatment Project
Manteca, CA
August 2023
FIGURES
Figure 1: Vicinity Map
Figure 2: Site Plan
ATTACHMENT 3
7/11/2023 4228_003 FIG 1 Vic Map.dwg
Figure 1
August 2023
File No. 4228.003
DISTANCE, FEET
0 2500 5000 7500 10000
SCALE: 1"= 5,000'
VICINITY MAP
City of Manteca Well 29 TCP Treatment
San Joaquin County, California
PROJECT
LOCATION
ATTACHMENT 3
7/11/2023 4228_003 FIG 2 Site Plan.dwg Figure 2 August 2023 File No. 4228.003 Source: Well 29 GAC Treatment, CEQA Figure A, HydroScience
L E G E N D
SITE PLAN
City of Manteca Well 29 TCP Treatment
San Joaquin County, California
Distance, feet
0 15 30 45 60
Approximate Location of SCALE: 1"= 30' BC-23-001 Blackburn Boring BC-23-2
BC-23-1
Alternate Site Improvement
Location
El Portal Avenue
Yosemite Park
ATTACHMENT
3 GEOTECHNICAL REPORT, REV 1
City of Manteca - Well 29 TCP
Treatment Project
Manteca, CA
August 2023
APPENDIX A
Boring Log Legend Boring Logs
ATTACHMENT 3
(ASTM D 2435)
(ASTM D 5333)
(ASTM D 698 & 1557, CTM 216)
(CTM 643,
CTM 417, CTM 422)
(ASTM D 4767)
(ASTM D 3080)
(ASTM D 4829)
(ASTM D 2216)
(ASTM D 2974)
(ASTM D 5084)
(ASTM D 6913 & 7928)
(ASTM D 4318)
(ASTM D 5731)
(CTM 301)
(CTM 217)
(AASHTO T100)
(ASTM D 4943)
(ASTM D 4546)
(ASTM D 2166)
(ASTM D 7012)
(ASTM D 2850)
(ASTM D 7263)
(AASHTO T223 / ASTM D 2573)
PAGE 1
California Sampler (2" ID)
Modified California Sampler (2.4" ID)
8/5/2019 Boring Legend for Reports 2019.dwg
BORING RECORD LEGEND
ATTACHMENT 3
PAGE 2
8/5/2019 Boring Legend for Reports 2019.dwg
BORING RECORD LEGEND
Extrudes between fingers when squeezed
ATTACHMENT 3
CR
DS
77 49
105
104
103
103
96 3
2 6
4 11
35 16
20 21
8 14
19 7
9 10
10 15
20 4
8 11
3 9
16 1
2 3
4 5
6 7
8 approximately 3-inch thick layer of TOPSOIL
SILTY SAND (SM); loose; very dark grayish brown; moist; nonplastic; mostly fine SAND; some fines
little fines
dense; light gray; dry; strong cementation; [HARDPAN]
SANDY SILT (ML); hard; mottled light gray and light brown; moist; low plasticity; some fine SAND
SILTY SAND (SM); medium dense; reddish brown with golden specks; moist; nonplastic; mostly fine SAND; little to some fines
grayish brown; low plasticity; some fines
Well-graded SAND (SW); medium dense; light yellowish
brown; dry; mostly fine to medium SAND; trace fines
mottled light yellowish brown and white
Lean CLAY with SAND (CL); very stiff; grayish brown; moist; medium plasticity; little to some fine SAND
SILTY SAND (SM); medium dense; brown with golden specks; moist; nonplastic; some fines
wet
dark gray; low plasticity; mostly fine to medium SAND; mostly fines
switched to mud rotary at 26.5 ft bgs
Lean CLAY (CL); very stiff; dark bluish gray; moist; medium plasticity; few fine SAND
90 100
100
55 80
60 100
85 7
9 9
3 29
3.25 1.5
OPERATOR'S NAME
Chad
LOCATION (Lat/Long or North/East and Datum)
37.79275° / -121.23249°
EQUIPMENT
CME 55 Crawler
DRILLING ROD TYPE AND DIAMETER / BUCKET WIDTH
BACKFILL AND COMPLETION AFTER (DATE)
Tremie neat cement grout
EXCAVATION METHOD
Solid-Stem Auger/Mud Rotary
HOLE ID
BC-23-1
CONTRACTOR
Taber
DURING
23.0 COMPLETION DATE
3-9-23
BEGIN DATE
3-9-23
GROUND WATER
READINGS
SAMPLER TYPE(S) AND SIZE(S) (ID)
SPT (1.4"), MCAL (2.4")
HELPER'S NAME
Caleb, Frank
HAMMER TYPE
Safety semi-automatic drop (140#/ 30")
LOGGED BY
LDM
CASING TYPE AND DIAMETER(in)
Steel, 6-inch
HAMMER EFFICIENCY, ERi
BOREHOLE DIAMETER
4 in
TOTAL DEPTH
51.5 ft
LOCATION (Offset, Station, Line) SURFACE ELEVATION
ELEVATION (ft)
Plasticity Index Additional Lab Tests Drilling Method
Laboratory Data
(continued) % <#200
CHECKED BY
RCP
SHEET
1 of 2
DEPTH (ft) Material Graphics
Sample LocationSample NumberBlows per 6 in.N60 (ASTM)Dry Density(pcf)
DESCRIPTION
PROJECT NAME
City of Manteca Well 29 TCP Treatment
FILE NO.
4228.003
CLIENT
Hydroscience
COUNTY
SJ
PREPARED BY
LDM
ROUTE POSTMILE Nfield / Push Pressure Recovery (%) Moisture Content (%) Liquid Limit Shear Strength Test
HOLE ID
BC-23-1 Pocket Pentrometer BCI LOG FOR SOIL TEMPLATE.GPJ LIBRARY_2022.GLB 4/5/23 8 46
41 33
19 35
19 25
0 1
2 3
4 5
6 7
8 9
10 11
12 13
14 15
16 17
18 19
20 21
22 23
24 25
26 27
28 29
30 ATTACHMENT 3
4 7
9 1
10 14
6 10
24 6
7 9
13 15
13 9
10 11
12 13
Lean CLAY (CL) (continued).
Poorly-graded SAND (SP); medium dense; brown; moist to
wet; fine through coarse SAND; trace fines
light gray
material from bottom tube fell out of sampler
coarse SAND to fine GRAVEL in drill cuttings
SANDY Lean CLAY (CL); very stiff; brown; moist; low to
medium plasticity; some fine SAND
SILTY SAND (SM); medium dense; brown; wet; nonplastic;
mostly fine to medium SAND; little fines
sampler shoe contains low plasticity; some fines
Bottom of exploration at 51.5 ft below ground surface (bgs) Tremie neat cement grout
Groundwater encountered at 23 ft bgs
Bulk A obtained from 0.25 to 5.0 ft bgs
100
85 65
65 85
3.0 3.0
ELEVATION (ft)
Plasticity Index Additional Lab Tests Drilling Method
Laboratory Data % <#200
CHECKED BY SHEET
2 of 2
DEPTH (ft) Material Graphics
Sample LocationSample NumberBlows per 6 in.N60 (ASTM)Dry Density(pcf)
DESCRIPTION
PROJECT NAME
City of Manteca Well 29 TCP Treatment
FILE NO.
4228.003
CLIENT
Hydroscience
COUNTY
SJ
PREPARED BY
LDM
ROUTE POSTMILE Nfield / Push Pressure Recovery (%) Moisture Content (%) Liquid Limit Shear Strength Test
HOLE ID
BC-23-1 Pocket Pentrometer BCI LOG FOR SOIL TEMPLATE.GPJ LIBRARY_2022.GLB 3/10/23 16 24
34 16
28 30
31 32
33 34
35 36
37 38
39 40
41 42
43 44
45 46
47 48
49 50
51 52
53 54
55 56
57 58
59 60
61 62
63 64
65 66
ATTACHMENT 3
4 4
5 33
50/2"
13 15
18 6
7 9
1 2
3 4
approximately 3-inch thick layer of TOPSOIL
SILTY SAND (SM); loose; light brown; moist; nonplastic; mostly fine SAND; little to some fines
dense to very dense; mottled light gray and light brown; dry; nonplastic to low plasticity; some fines; strong cementation; [HARDPAN]
moist; low plasticity; increasing fines content; no cementation medium dense
Poorly-graded SAND (SP); medium dense; mottled white and light yellowish brown; moist; medium SAND; trace fines
Bottom of exploration at 11.5 ft below ground surface (bgs) Top pour neat cement grout
Groundwater not encountered
Bulk A obtained from 0.25 to 5.0 ft bgs
100
100
80 85
3.0 OPERATOR'S NAME
Chad
LOCATION (Lat/Long or North/East and Datum)
EQUIPMENT
CME 55 Crawler
DRILLING ROD TYPE AND DIAMETER / BUCKET WIDTH
BACKFILL AND COMPLETION AFTER (DATE)
Top pour neat cement grout
EXCAVATION METHOD
Solid-Stem Auger
HOLE ID
BC-23-2
CONTRACTOR
Taber
DURING
Not encountered
COMPLETION DATE
3-9-23
BEGIN DATE
3-9-23
GROUND WATER
READINGS
SAMPLER TYPE(S) AND SIZE(S) (ID)
SPT (1.4"), MCAL (2.4")
HELPER'S NAME
Caleb, Frank
HAMMER TYPE
Safety semi-automatic drop (140#/ 30")
LOGGED BY
LDM
CASING TYPE AND DIAMETER(in)
HAMMER EFFICIENCY, ERi
BOREHOLE DIAMETER
4 in
TOTAL DEPTH
11.5 ft
LOCATION (Offset, Station, Line) SURFACE ELEVATION
ELEVATION (ft)
Plasticity Index Additional Lab Tests Drilling Method
Laboratory Data % <#200
CHECKED BY SHEET
1 of 1
DEPTH (ft) Material Graphics
Sample LocationSample NumberBlows per 6 in.N60 (ASTM)Dry Density(pcf)
DESCRIPTION
PROJECT NAME
City of Manteca Well 29 TCP Treatment
FILE NO.
4228.003
CLIENT
Hydroscience
COUNTY
SJ
PREPARED BY
LDM
ROUTE POSTMILE Nfield / Push Pressure Recovery (%) Moisture Content (%) Liquid Limit Shear Strength Test
HOLE ID
BC-23-2 Pocket Pentrometer BCI LOG FOR SOIL TEMPLATE.GPJ LIBRARY_2022.GLB 3/10/23 9 50/2''
33 16
0 1
2 3
4 5
6 7
8 9
10 11
12 13
14 15
16 17
18 19
20 21
22 23
24 25
26 27
28 29
30 ATTACHMENT 3
GEOTECHNICAL REPORT, REV 1
City of Manteca - Well 29 TCP
Treatment Project
Manteca, CA
August 2023
APPENDIX B
Laboratory Test Results
ATTACHMENT 3
DIRECT SHEAR TEST REPORT
Blackburn Consulting
W. Sacramento, CA
Client: Hydroscience
Project: City of Manteca Well 29 TCP Treatment
Source of Sample: BC-23-01 Depth: 2.5-3'
Sample Number: 1C
Proj. No.: 4228.X003 Date Sampled:
Sample Type: CalMod
Description: SILTY SAND, very dark grayish
brown
Assumed Specific Gravity= 2.7
Remarks:
Figure
Sample No.
Water Content, %
Dry Density, pcf
Saturation, %
Void Ratio
Diameter, in.
Height, in.
Water Content, %
Dry Density, pcf
Saturation, %
Void Ratio
Diameter, in.
Height, in.
Normal Stress, psf
Fail. Stress, psf
Strain, %
Ult. Stress, psf
Strain, %
Strain rate, in./min. Initial At Test Shear Stress, psf 0 500
1000
1500
2000
2500
3000
Strain, %
0 10 20 30 40
1 2
3 Vertical Deformation, in.
0.045
0.03 0.015
0 -0.015
-0.03
-0.045
Strain, %
0 5.5 11 16.5 22
Dilation Consol. 1
2 3 Fail. Stress, psf
0 2000
4000
6000
Normal Stress, psf
0 2000 4000 6000
C, psf
f, deg
Tan(f)
Results
91.2 24.9
0.46 1
7.4 104.1
32.3 0.6186
2.400
1.000
18.7 106.1
85.8 0.5885
2.400
0.981
1000.0
487.0
2.9 0.003
2 7.3
106.0
33.6 0.5896
2.400
1.000
18.2 107.9
87.6 0.5615
2.400
0.982
2000.0
1152.3
5.0 0.003
3 7.4
106.1
33.9 0.5892
2.400
1.000
17.7 109.3
88.3 0.5419
2.400
0.970
3000.0
1413.3
6.0 0.003
ATTACHMENT 3
Particle Size Distribution Report PERCENT FINER
0 10
20 30
40 50
60 70
80 90
100
GRAIN SIZE - mm.
100 10 1 0.1 0.01 0.001 0.0001
% +3" Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
76.5 6 in. 3 in. 2 in. 1½ in. 1 in. ¾ in.
½ in. 3/8 in. #4#10 #20 #30 #40 #60 #100 #140 #200
SIEVE SIZE PERCENT SPEC.* PASS?
OR DIAMETER FINER PERCENT (X=NO)
Atterberg Limits
Coefficients
Classification
Remarks
Source of Sample: BC-23-01 Depth: 21-21.5'
Sample Number: 7C Date:
Client:
Project:
Project No: Figure
Soil Description
Lean CLAY with SAND, brown
#200 76.5
Hydroscience
City of Manteca Well 29 TCP Treatment
4228.X003
PL= LL= PI=
D90= D85= D60= D50= D30= D15= D10= Cu
= Cc= USCS= AASHTO=
* (no specification provided)
Blackburn Consulting
W. Sacramento, CA
ATTACHMENT 3
Particle Size Distribution Report PERCENT FINER
0 10
20 30
40 50
60 70
80 90
100
GRAIN SIZE - mm.
100 10 1 0.1 0.01 0.001 0.0001
% +3" Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
48.6 6 in. 3 in. 2 in. 1½ in. 1 in. ¾ in.
½ in. 3/8 in. #4#10 #20 #30 #40 #60 #100 #140 #200
SIEVE SIZE PERCENT SPEC.* PASS?
OR DIAMETER FINER PERCENT (X=NO)
Soil Description
Atterberg Limits
Coefficients
Classification
Remarks
Source of Sample: BC-23-01 Depth: 25.5-26'
Sample Number: 8B Date:
Client:
Project:
Project No: Figure
SILTY SAND, very dark grey
#200 48.6
Hydroscience
City of Manteca Well 29 TCP Treatment
4228.X003
PL= LL= PI=
D90= D85= D60= D50= D30= D15= D10= Cu
= Cc= USCS= AASHTO=
* (no specification provided)
Blackburn Consulting
W. Sacramento, CA
ATTACHMENT 3
Particle Size Distribution Report PERCENT FINER
0 10
20 30
40 50
60 70
80 90
100
GRAIN SIZE - mm.
100 10 1 0.1 0.01 0.001 0.0001
% +3" Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
1.2 6 in. 3 in. 2 in. 1½ in. 1 in. ¾ in.
½ in. 3/8 in. #4#10 #20 #30 #40 #60 #100 #140 #200
SIEVE SIZE PERCENT SPEC.* PASS?
OR DIAMETER FINER PERCENT (X=NO)
Soil Description
Atterberg Limits
Coefficients
Classification
Remarks
Source of Sample: BC-23-01 Depth: 40.5-41'
Sample Number: 11B Date:
Client:
Project:
Project No: Figure
Poorly-graded SAND, grayish brown
#200 1.2
SP
Hydroscience
City of Manteca Well 29 TCP Treatment
4228.X003
PL= LL= PI=
D90= D85= D60= D50= D30= D15= D10= Cu
= Cc= USCS= AASHTO=
* (no specification provided)
Blackburn Consulting
W. Sacramento, CA
ATTACHMENT 3
Particle Size Distribution Report PERCENT FINER
0 10
20 30
40 50
60 70
80 90
100
GRAIN SIZE - mm.
100 10 1 0.1 0.01 0.001 0.0001
% +3" Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
79.7 6 in. 3 in. 2 in. 1½ in. 1 in. ¾ in.
½ in. 3/8 in. #4#10 #20 #30 #40 #60 #100 #140 #200
SIEVE SIZE PERCENT SPEC.* PASS?
OR DIAMETER FINER PERCENT (X=NO)
Atterberg Limits
Coefficients
Classification
Remarks
Source of Sample: BC-23-01 Depth: 45-46.5'
Sample Number: 12 Date:
Client:
Project:
Project No: Figure
Soil Description
Lean CLAY with SAND, very dark grayish brown
#200 79.7
Hydroscience
City of Manteca Well 29 TCP Treatment
4228.X003
PL= LL= PI=
D90= D85= D60= D50= D30= D15= D10= Cu
= Cc= USCS= AASHTO=
* (no specification provided)
Blackburn Consulting
W. Sacramento, CA
ATTACHMENT 3
LIQUID AND PLASTIC LIMITS TEST REPORT PLASTICITY INDEX
0 10
20 30
40 50
60 LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
CL or OL
CH or OH
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
4 7 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client: Remarks:
Project:
Blackburn Consulting
W. Sacramento, CA Figure
Source of Sample: BC-23-01 Depth: 30.5-31' Sample Number: 9B Lean CLAY, dark greenish grey 43 18 25
4228.X003 Hydroscience
City of Manteca Well 29 TCP Treatment
ATTACHMENT 3
ATTACHMENT 3
GEOTECHNICAL REPORT, REV 1
City of Manteca - Well 29 TCP
Treatment Project
Manteca, CA
August 2023
APPENDIX C
Important Information about This Geotechnical Engineering Report, Geoprofessional Business Association, 2019
ATTACHMENT 3
Geotechnical-Engineering Report
Important Information about This
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
While you cannot eliminate all such risks, you can manage them. The following information is provided to help.
The Geoprofessional Business Association (GBA)
has prepared this advisory to help you – assumedly
a client representative – interpret and apply this
geotechnical-engineering report as effectively as
possible. In that way, you can benefit from a lowered
exposure to problems associated with subsurface
conditions at project sites and development of
them that, for decades, have been a principal cause
of construction delays, cost overruns, claims,
and disputes. If you have questions or want more
information about any of the issues discussed herein,
contact your GBA-member geotechnical engineer.
Active engagement in GBA exposes geotechnical
engineers to a wide array of risk-confrontation
techniques that can be of genuine benefit for
everyone involved with a construction project.
Understand the Geotechnical-Engineering Services
Provided for this Report
Geotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from eld exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or a
ected by construction activities.
e culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project.
ese reports may be
titled investigations, explorations, studies, assessments, or evaluations.
Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions.
Geotechnical-Engineering Services are Performed
for Specific Purposes, Persons, and Projects,
and At Specific Times
Geotechnical engineers structure their services to meet the speci c needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a di
erent civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client.
Likewise, geotechnical-engineering services are performed for a speci c project and purpose. For example, it is unlikely that a geotechnicalengineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project.
Do not rely on this report if your geotechnical engineer prepared it:
• for a di
erent client;
• for a di
erent project or purpose;
• for a di
erent site (that may or may not include all or a portion of the original site); or
• before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like
oods, droughts, earthquakes,
or groundwater
uctuations.
Note, too, the reliability of a geotechnical-engineering report can be a
ected by the passage of time, because of factors like changed subsurface conditions; new or modi ed codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis aer the passage of time – if any is required at all – could prevent major problems.
Read this Report in Full
Costly problems have occurred because those relying on a geotechnicalengineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full.
You Need to Inform Your Geotechnical Engineer
About Change
Your geotechnical engineer considered unique, project-speci c factors when developing the scope of study behind this report and developing the con rmation-dependent recommendations the report conveys.
Typical changes that could erode the reliability of this report include those that a
ect:
• the site’s size or shape;
• the elevation, con guration, location, orientation,
function or weight of the proposed structure and
the desired performance criteria;
• the composition of the design team; or
• project ownership.
As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. e geotechnical engineer who prepared this report cannot accept ATTACHMENT 3
responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered.
Most of the “Findings” Related in This Report
Are Professional Opinions
Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those speci c
locations where sampling and testing is performed.
e data derived from
that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may di
er – maybe signi cantly – from those indicated in
this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed.
This Report’s Recommendations Are
Confirmation-Dependent
e recommendations included in this report – including any options or alternatives – are con rmation-dependent. In other words, they are not nal, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can nalize the recommendations only a
er observing actual subsurface conditions
exposed during construction. If through observation your geotechnical engineer con rms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. e geotechnical engineer who prepared this report cannot assume responsibility or liability for con
rmation-dependent recommendations if you
fail to retain that engineer to perform construction observation.
This Report Could Be Misinterpreted
Other design professionals’ misinterpretation of geotechnicalengineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to:
• confer with other design-team members;
• help develop speci cations;
• review pertinent elements of other design professionals’ plans and speci cations; and
• be available whenever geotechnical-engineering guidance is needed.
You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform constructionphase observations.
Give Constructors a Complete Report and Guidance
Some owners and design professionals mistakenly believe they can shi unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about speci c project requirements, including options selected from the report, only from the design drawings and speci cations. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the nancial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect.
Read Responsibility Provisions Closely
Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines.
is happens in part because soil and rock on
project sites are typically heterogeneous and not manufactured materials with well-de ned engineering properties like steel and concrete. at
lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes.
To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions.
Your geotechnical engineer should respond fully and frankly.
Geoenvironmental Concerns Are Not Covered
e personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – di
er signi cantly from those used to perform a
geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental ndings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to nd environmental risk-management guidance.
Obtain Professional Assistance to Deal with
Moisture Infiltration and Mold
While your geotechnical engineer may have addressed groundwater, water in ltration, or similar issues in this report, the engineer’s services were not designed, conducted, or intended to prevent migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance de ciencies.
Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be su cient to prevent moisture in
ltration. Confront the risk of moisture in
ltration by
including building-envelope or mold specialists on the design team.
Geotechnical engineers are not building-envelope or mold specialists.
Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s speci c written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind.
Any other rm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation.
Telephone: 301/565-2733
e-mail: [email protected] www.geoprofessional.org ATTACHMENT 3
Draft Initial Study/Mitigated Negative Declaration
APPENDIX F
Roadway Construction Noise Model
ECORP Consulting, Inc. 2023
ATTACHMENT 3
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 5/9/2023
Case Description: Demolition
Description Affected Land Use
Demolition Residential
Equipment
Spec Actual Receptor
Impact Lmax Lmax Distance
Description Device Usage(%) (dBA) (dBA) (feet)
Flat Bed Truck No 40 74.3 170
Flat Bed Truck No 40 74.3 170
Tractor No 40 84 170
Dump Truck No 40 76.5 170
Calculated (dBA)
Equipment *Lmax Leq
Flat Bed Truck 63.6 59.6
Flat Bed Truck 63.6 59.6
Tractor 73.4 69.4
Dump Truck 65.8 61.8
Total 73.4 70.8
*Calculated Lmax is the Loudest value.
ATTACHMENT 3
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 5/9/2023
Case Description: Grading
Description Affected Land Use
Grading Residential
Equipment
Spec Actual Receptor
Impact Lmax Lmax Distance
Description Device Usage(%) (dBA) (dBA) (feet)
Flat Bed Truck No 40 74.3 170
Tractor No 40 84 170
Calculated (dBA)
Equipment *Lmax Leq
Flat Bed Truck 63.6 59.6
Tractor 73.4 69.4
Total 73.4 69.8
*Calculated Lmax is the Loudest value.
ATTACHMENT 3
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 5/9/2023
Case Description: Underground Piping & Electrical
Description Affected Land Use
Underground Piping & Electrical Residential
Equipment
Spec Actual Receptor
Impact Lmax Lmax Distance
Description Device Usage(%) (dBA) (dBA) (feet)
Flat Bed Truck No 40 74.3 170
Flat Bed Truck No 40 74.3 170
Tractor No 40 84 170
Crane No 16 80.6 170
Dump Truck No 40 76.5 170
Roller No 20 80 170
Calculated (dBA)
Equipment *Lmax Leq
Flat Bed Truck 63.6 59.6
Flat Bed Truck 63.6 59.6
Tractor 73.4 69.4
Crane 69.9 62
Dump Truck 65.8 61.8
Roller 69.4 62.4
Total 73.4 71.9
*Calculated Lmax is the Loudest value.
ATTACHMENT 3
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 5/9/2023
Case Description: Paving
Description Affected Land Use
Paving Residential
Equipment
Spec Actual Receptor
Impact Lmax Lmax Distance
Description Device Usage(%) (dBA) (dBA) (feet)
Flat Bed Truck No 40 74.3 170
Flat Bed Truck No 40 74.3 170
Concrete Mixer Truck No 40 78.8 170
Concrete Mixer Truck No 40 78.8 170
Calculated (dBA)
Equipment *Lmax Leq
Flat Bed Truck 63.6 59.6
Flat Bed Truck 63.6 59.6
Concrete Mixer Truck 68.2 64.2
Concrete Mixer Truck 68.2 64.2
Total 68.2 68.5
*Calculated Lmax is the Loudest value.
ATTACHMENT 3
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 5/9/2023
Case Description: Miscellaneous Activities
Description Affected Land Use
Miscellaneous Activities Residential
Equipment
Spec Actual Receptor
Impact Lmax Lmax Distance
Description Device Usage(%) (dBA) (dBA) (feet)
Flat Bed Truck No 40 74.3 170
Flat Bed Truck No 40 74.3 170
Calculated (dBA)
Equipment *Lmax Leq
Flat Bed Truck 63.6 59.6
Flat Bed Truck 63.6 59.6
Total 63.6 62.7
*Calculated Lmax is the Loudest value.
ATTACHMENT 3
www.ecorpconsul
Ɵng.com
ROCKLIN, CA
(916) 782‐9100
CHICO, CA
(530) 805‐2585
FLAGSTAFF, AZ
(858) 232‐9602
REDLANDS, CA
(909) 307‐0046
SAN DIEGO, CA
(858) 275‐4040
SANTA ANA, CA
(714) 648‐0630
SANTA FE, NM
(714) 222‐5932
ATTACHMENT 3