HomeMy WebLinkAboutLD21-3700Permit Number: LD21-3700
LD - Onsite Improvements/ Commercial/Industrial Development
Issued: 02/24/2025
Expired: 09/08/2025
Job Address: Parcel Map 38166
Legal Description:
City of Temecula - Land Development Division
41000 Main Street - Temecula, CA 92590
Mailing Address: P.O. Box 9033 Temecula, CA 92589-9033
Phone: (951) 308-6395 Fax: (951) 694-6475
ANY NOTICE OR NOTICES REQUIRED TO BE GIVEN PURSUANT TO THIS PERMIT SHALL BE SERVED
ON THE OTHER PARTY BY FIRST CLASS MAIL, POSTAGE PREPAID, AT THE FOLLOWING ADDRESS:
Joel Waymire
2514 Jamacha Road, Suite 502-31
El Cajon, CA 92019
Applicant:
Contractor:
Description of Work: The City Engineer hereby authorizes the Property Owner and Applicant (if different from
Property Owner) (hereinafter collectively referred to a "Permittee") to do the following work including backfilling,
compaction, surfacing and/or as outlined in the description of work below:
Description:
Parcel Map 38166 - Lantern Crest Precise Grading Plan
Perform grading in accordance with approved Grading Plans dated . A pre-grading conference is required
48 hours (minimum) in advance of any work done under this permit with the grading contractor and
City Inspector. A pre-grade meeting is required 48 hours prior to any work. Permittee shall contact e-mail
LDinspections@TemeculaCA.gov to schedule a meeting. Any field changes to the plan shall be approved by
the City Engineer. All required permits and inspections by Building and Safety for walls, etc. shall be completed
prior to any releases and/or other permits issued or released. Traffic and dust control shall be reviewed and
approved by the inspector.
Permitee Date
City Engineer or Authorized Representative Date
02/24/2025
Page 1 of 1
DATE:3/17/2023 Job ID:
JURISDICTION:Temecula
PERMIT NUMBER:
REVIEW #:
TM-LD21-3700.e
PROJECT NAME:
PROJECT ADDRESS:
TM21-1049
3
Grading plan
Track, Temecula
☒Interwest did not advise the applicant that the construction documents have been reviewed. The Jurisdiction
shall provide all notifications to the applicant.
☐Interwest did advise the applicant that the construction documents have been reviewed.
Contact Name:
Email:
Contact Company:
Telephone #:
Date Contacted: Contact By:
Erich Kuchar - Accessibility - ekuchar@esgil.com - (858) 560-1468
Interwest
☒RECOMMENDED FOR APPROVAL YES NO☐
The reviewed construction documents substantially comply with the jurisdiction’s building codes.
☐There are Conditions of Approval and/or Redlines identified below:
☐RESUBMITTAL REQUIRED YES NO☒
The reviewed construction documents require revision and resubmittal. Please review the Resubmittal Instructions
section of this transmittal. The plan review corrections are a separate PDF document titled with the permit number,
sent in the same email as this transmittal.
☒Plan review corrections have been sent to the following jurisdiction contacts:
Emails hidden upon request
The paper plans are being held at Interwest until corrected plans are submitted for recheck.
☒The plans were provided electronically.
☐The plans were provided in paper or other format.
Additional Remarks:
Enclosures:
Please contact the individual reviewer(s) listed on the plan comment letter between 9:00 A.M. and 4:00 P.M., M-F,
with any questions.
By:
Interwest - 9320 Chesapeake Dr, Suite 208, San Diego, CA 92123
City of Temecula
WATER QUALITY MANAGEMENT PLAN (WQMP)
LANTERN CREST TEMECULA
PA19-1452, LD21-3700
SOUTHEAST CORNER OF DATE STREET & YNEZ ROAD
APN’s: 916-400-043, 044, 062, 064 & 065
PREPARED BY:
Name Polaris Development Consultants, Inc.
Address 2514 Jamacha Road, Suite 502-31
El Cajon, CA 92019
Phone (619) 248-2932
Email joel@polarisdc.com
PREPARED FOR:
Name Lantern Crest at Temecula, LLC.
Address 800 Lantern Crest Way
Santee, CA 92071
Phone (619) 449-0249
Email mgrant@mgrantcompanies.com
OCTOBER 7, 2024
APPROVED BY: _______________________
APPROVAL DATE: _____________________
PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 9
Template Date: September 26, 2019 Preparation Date: November 3, 2022
Provide details regarding the proposed project site drainage conveyance network, including
storm drains, concrete channels, swales, detention facilities, stormwater treatment facilities,
natural or constructed channels, and the method for conveying offsite flows through or around
the proposed project site. Identify all discharge locations from the proposed project site along
with a summary of the conveyance system size and capacity for each of the discharge
locations. Provide a summary of pre- and post-project drainage areas and design flows to each
of the runoff discharge locations. Reference the drainage study for detailed calculations.
Describe proposed site drainage patterns:
The proposed project will collect runoff in grated inlets within the drive aisles and convey the
runoff in underground pipes to the biofiltration basin in the southwest corner of the site. Runoff
will percolate through the basin soil matrix and into the native soil. Large storm flows that cannot
be infiltrated into the native soil will be captured in an underdrain and/or an overflow inlet, which
will convey the runoff to the west into the existing storm drain in Date Street. A small amount of
runoff at the easterly entry will be captured and treated with pervious pavers. The runoff on
Equity Drive on the south side of the project cannot be treated in the biofiltration area due to its
lower elevation, so it will be treated with an inlet filter. To offset this uncaptured area, a portion
of the runoff from the existing pavement on the south side of Ynez Road and the east side of
Date Street will be captured and directed into the biofiltration area. This off-site area of Ynez
Road and Date Street will be equal to or greater than the area of DMA #4.
Step 1.3: Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence stormwater
management design, such as zoning requirements including setbacks and open space, or local
codes governing minimum street width, sidewalk construction, allowable pavement types, and
drainage requirements.
No constraints.
PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 11
Template Date: September 26, 2019 Preparation Date: November 3, 2022
Step 2: Strategy for Meeting PDP Performance Requirements
PDPs must implement BMPs to control pollutants in stormwater that may be discharged from a
project (see Chapter 5). PDPs subject to hydromodification management requirements must
implement flow control BMPs to manage hydromodification (see Chapter 6). Both stormwater
pollutant control and flow control can be achieved within the same BMP(s). Projects triggering
the 50% rule must address stormwater requirements for the entire site.
Structural BMPs must be verified by the City at the completion of construction. This may include
requiring the project owner or project owner's representative and engineer of record to certify
construction of the structural BMPs (see Chapter 1.12). Structural BMPs must be maintained
into perpetuity, and the City must confirm the maintenance (see Chapter 7).
Provide a narrative description of the general strategy for pollutant control and flow control at
the project site in the box below. This information must describe how the steps for selecting and
designing stormwater pollutant control BMPs presented in Chapter 5.1 of the BMP Design
Manual were followed, and the results (type of BMPs selected). For projects requiring flow
control BMPs, indicate whether pollutant control and flow control BMPs are integrated or
separate. At the end of this discussion, provide a summary of all the BMPs within the project
including the type and number.
Describe the general strategy for BMP implementation at the site.
The project site is exempt from hydromodification, so only pollutant control BMP's will be
provided. The site is currently graded so that most of the site drains to the southwest corner and
the runoff is collected and conveyed into the public storm drain system in Date Street. The
proposed BMP design consists of a biofiltration basin in the southwest corner of the site that will
provide the required pollutant control for DMA’s 1 and 5, and pervious pavers that will provide
pollutant control for DMA 2. DMA 3 is a self-mitigating area. The runoff on Equity Drive on the
south side of the project cannot be treated in the biofiltration area due to its lower elevation, so it
will be treated with an inlet filter. To offset this uncaptured area, a portion of the runoff from the
existing pavement on the south side of Ynez Road and the east side of Date Street (DMA #5)
will be captured and directed into the biofiltration area. This off-site area of Ynez Road and Date
Street will be equal to or greater than the area of DMA #4.
(Continue on following page as necessary.)
BF-2 Nutrient Sensitive Media Design
E-134 July 2018
E.19 BF-2 Nutrient Sensitive Media Design
Some studies of biofiltration with underdrains have observed export of nutrients, particularly
inorganic nitrogen (nitrate and nitrite) and dissolved phosphorus. This has been observed to be a
short-lived phenomenon in some studies or a long term issue in some studies. The composition of
the soil media, including the chemistry of individual elements is believed to be an important factor in
the potential for nutrient export. Organic amendments, often compost, have been identified as the
most likely source of nutrient export. The quality and stability of organic amendments can vary
widely.
The biofiltration media specifications contained in the County of San Diego Low Impact
Development Handbook: Appendix G - Biofiltration Soil Specification (June 2014, unless
superseded by more recent edition) and the City of San Diego Low Impact Development Design
Manual (page B-18) (July 2011, unless superseded by more recent edition) were developed with
consideration of the potential for nutrient export. These specifications include criteria for individual
component characteristics and quality in order to control the overall quality of the blended mixes.
As of the publication of this manual, the June 2014 County of San Diego specifications provide
more detail regarding mix design and quality control.
The City and County specifications noted above were developed for general purposes to meet
permeability and treatment goals. In cases where the BMP discharges to receiving waters with
nutrient impairments or nutrient TMDLs, the biofiltration media should be designed with the
specific goal of minimizing the potential for export of nutrients from the media. Therefore, in
addition to adhering to the City or County media specifications, the following guidelines should be
followed:
1. Select plant palette to minimize plant nutrient needs
A landscape architect or agronomist should be consulted to select a plant palette that minimizes
nutrient needs. Utilizing plants with low nutrient needs results in less need to enrich the biofiltration
soil mix. If nutrient quantity is then tailored to plants with lower nutrient needs, these plants will
generally have less competition from weeds, which typically need higher nutrient content. The
following practices are recommended to minimize nutrient needs of the plant palette:
Utilize native, drought-tolerant plants and grasses where possible. Native plants
generally have a broader tolerance for nutrient content, and can be longer lived in
leaner/lower nutrient soils.
Start plants from smaller starts or seed. Younger plants are generally more tolerant of
lower nutrient levels and tend to help develop soil structure as they grow. Given the lower
cost of smaller plants, the project should be able to accept a plant mortality rate that is
somewhat higher than starting from larger plants and providing high organic content.
2. Minimize excess nutrients in media mix
BF-2 Nutrient Sensitive Media Design
E-135 July 2018
Once the low-nutrient plant palette is established (item 1), the landscape architect and/or
agronomist should be consulted to assist in the design of a biofiltration media to balance the
interests of plant establishment, water retention capacity (irrigation demand), and the potential for
nutrient export. The following guidelines should be followed:
The mix should not exceed the nutrient needs of plants. In conventional landscape
design, the nutrient needs of plants are often exceeded intentionally in order to provide a
factor of safety for plant survival. This practice must be avoided in biofiltration media as
excess nutrients will increase the chance of export. The mix designer should keep in mind
that nutrients can be added later (through mulching, tilling of amendments into the surface),
but it is not possible to remove nutrients, once added.
The actual nutrient content and organic content of the selected organic amendment
source should be determined when specifying mix proportions. Nutrient content (i.e.,
C:N ratio; plant extractable nutrients) and organic content (i.e, % organic material) are
relatively inexpensive to measure via standard agronomic methods and can provide
important information about mix design. If mix design relies on approximate assumption
about nutrient/organic content and this is not confirmed with testing (or the results of prior
representative testing), it is possible that the mix could contain much more nutrient than
intended.
Nutrients are better retained in soils with higher cation exchange capacity. Cation
exchange capacity can be increased through selection of organic material with naturally high
cation exchange capacity, such as peat or coconut coir pith, and/or selection of inorganic
material with high cation exchange capacity such as some sands or engineer ed minerals (e.g.,
low P-index sands, zeolites, rhyolites, etc). Including higher cation exchange capacity
materials would tend to reduce the net export of nutrients. Natural silty materials also
provide cation exchange capacity; however potential impacts to permeability need to be
considered.
Focus on soil structure as well as nutrient content. Soil structure is loosely defined as the
ability of the soil to conduct and store water and nutrients as well as the degree of aeration
of the soil. Soil structure can be more important than nutrient content in plant survival and
biologic health of the system. If a good soil structure can be created with very low amounts
of organic amendment, plants survivability should still be provided. While soil structure
generally develops with time, biofiltration media can be designed to promote earlier
development of soil structure. Soil structure is enhanced by the use of amendments with
high humus content (as found in well-aged organic material). In addition, soil structure can
be enhanced through the use of organic material with a distribution of particle sizes (i.e., a
more heterogeneous mix).
Consider alternatives to compost. Compost, by nature, is a material that is continually
evolving and decaying. It can be challenging to determine whether tests previously done on a
given compost stock are still representative. It can also be challenging to determine how the
properties of the compost will change once placed in the media bed. More stable materials
BF-2 Nutrient Sensitive Media Design
E-136 July 2018
such as aged coco coir pith, peat, biochar, shredded bark, and/or other amendments should
be considered.
With these considerations, it is anticipated that less than 10 percent organic amendment by volume
could be used, while still balancing plant survivability and water retention. If compost is used,
designers should strongly consider utilizing less than 10 percent by volume.
3. Design with partial retention and/or internal water storage
An internal water storage zone, as described in Fact Sheet PR-1 is believed to improve retention of
nutrients. For lined systems, an internal water storage zone worked by providing a zone that
fluctuates between aerobic and anaerobic conditions, resulting in nitrification/denitrification. In
soils that will allow infiltration, a partial retention design (PR-1) allows significant volume reduction
and can also promote nitrification/denitrification.
Acknowledgment: This fact sheet has been adapted from the Orange County Technical Guidance
Document (May 2011). It was originally developed based on input from: Deborah Deets, City of
Los Angeles Bureau of Sanitation, Drew Ready, Center for Watershed Health, Rick Fisher, ASLA,
City of Los Angeles Bureau of Engineering, Dr. Garn Wallace, Wallace Laboratories, Glen Dake,
GDML, and Jason Schmidt, Tree People. The guidance provided herein does not reflect the
individual opinions of any individual listed above and should not be cited or otherwise attributed to
those listed.
Refer to maintenance information provided in the Biofiltration (BF-1) Fact Sheet. Adjust
maintenance actions and reporting if required based on the specific media design.
Maintenance Overview
City of Temecula
STRUCTURAL BMP VERIFICATION PACKAGE
Project Information
Project Name Lantern Crest at Temecula
Record ID (e.g., grading/improvement plan
number)
LD21-3700
Project Address
East side of Date Street, south of Ynez Road
Assessor's Parcel Number(s) (APN(s)) 916-400-43, 44, 62, 64 & 65
Project Watershed
(Complete Hydrologic Unit, Area, and
Subarea Name with Numeric Identifier)
Santa Margarita
902.3 Murrieta
Responsible Party for Construction Phase
Developer's Name Lantern Crest at Temecula, LLC
Address
800 Lantern Crest Way
Santee, CA 92071
Email Address Mgrant@mgrantcompanies.com
Phone Number 619-449-0249
Engineer of Work Polaris Development Consultants, Inc.
Engineer's Phone Number 619-248-2932
Responsible Party for Ongoing Maintenance
Owner's Name(s)* Lantern Crest at Temecula, LLC
Address
800 Lantern Crest Way
Santee, CA 92071
Email Address Mgrant@mgrantcompanies.com
Phone Number 619-449-0249
*Note: If a corporation or LLC, provide information for principal partner or Agent for Service of
Process. If an HOA, provide information for the Board or property manager at time of project
closeout.
Submit to LDInspections@TemeculaCA.gov
2 STRUCTURAL BMP VERIFICATION INFORMATION
Template Date: August 14th, 2022 Preparation Date: _May 23, 2024_______
Stormwater Structural Pollutant Control & Hydromodification Control BMPs*
(List all from WQMP)
Description/Type of
Structural BMP
Plan
Sheet
# BMP ID#
Maintenance
Agreement
Recorded Doc
# Revisions
Biofiltration Basin 7 BMP #1
Pervious Pavers BMP #2
Filter Insert 8 BMP #3
Note: If this is a partial verification of Structural BMPs, provide a list and map denoting
Structural BMPs that have already been submitted, those for this submission, and those
anticipated in future submissions.
3 STRUCTURAL BMP VERIFICATION INFORMATION
Template Date: August 14th, 2022 Preparation Date: _May 23, 2024_______
Provide the following items for each Structural BMP selected
DMA ID No. Structural BMP ID No. Construction Plan Sheet No.
Structural BMP Verification Checklist: complete and include the Construction Verification and
Maintenance checklists from the associated fact sheets found in appendix E for selected
Structural BMP(s) along with the following items:
☐ Photograph of each completed Structural BMP.
☐ Photograph(s) of each Structural BMP during the construction process to illustrate
proper construction as described in the Structural BMP Fact sheets.
☐ Certificates of compliance for materials as required in the Structural BMP Fact sheets.
☐ Infiltration Tests as required in the Structural BMP Fact sheets.
☐ All DMAs draining to the structural BMP have been permanently stabilized and cleaned
of all trash and debris.
☐ All drainage systems draining to the structural BMP have been inspected and cleaned
and are free of trash and debris.
Purpose:
☐ Pre-treatment/forebay for another structural BMP
☐ Pollutant control only
☐ Combined pollutant control and hydromodification control
☐ Other (describe in discussion section below)
Who will be the final owner of this BMP?
☐ HOA ☐ Property Owner ☐ City
☐ Other (describe)
Who will maintain this BMP into perpetuity?
☐ HOA ☐ Property Owner ☐ City
☐ Other (describe)
Discussion (as needed):
By signing below, I certify that the Structural BMP(s) for this project have been constructed and
all BMPs are in substantial conformance with the approved plans and applicable regulations. I
understand the City reserves the right to inspect the above BMPs to verify compliance with the
approved plans and City Ordinances. Should it be determined that the BMPs were not
constructed to plan or code, corrective actions may be necessary before permits can be closed.
Professional Engineer's Printed Name:
Professional Engineer's Signed Name:
Date:
4 STRUCTURAL BMP VERIFICATION INFORMATION
Template Date: August 14th, 2022 Preparation Date: _May 23, 2024_______
City of Temecula Certification
City - OFFICIAL USE ONLY:
For City Inspector: Verification Package #: __________
City Inspector:
Date Project has/expects to close:
Date verification received from EOW:
By signing below, City Inspector concurs that every noted Structural BMP has been installed per
plan.
City Inspector’s Signature: _______________________________ Date:
For Land Development Staff:
Date Received from City Inspector:
Land Development Submittal Reviewer:
Land Development Reviewer concurs that the information provided for the following Structural
BMPs is acceptable to enter into the Structural BMP Maintenance verification inventory:
List acceptable Structural BMPs:
Land Development Reviewer’s Signature: Date:
UPDATE GEOTECHNICAL
INVESTIGATION
LANTERN CREST MULTI-FAMILY
DEVELOPMENT
SOUTHEAST OF YNEZ ROAD AND
DATE STREET
TEMECULA, CALIFORNIA
PREPARED FOR
THE GRANT COMPANIES
RAMONA, CALIFORNIA
MARCH 27, 2020
PROJECT NO. T2903-22-01
78-075 Main Street #G -203 ■ La Quinta, California 92253 ■ Telephone 760.565.2002 ■ Fax 951.304.2392
Project No. T2903-22-01
March 27, 2020
The Grant Companies
8520 Railroad Avenue
Santee, California 92071
Attention: Mr. Michael Grant
Subject: UPDATE GEOTECHNICAL INVESTIGATION
LANTERN CREST MULTI-FAMILY DEVELOPMENT
SOUTHEAST OF YNEZ ROAD AND DATE STREET
TEMECULA, CALIFORNIA
Dear Mr. Grant:
In accordance with your authorization of our Proposal IE-2540 dated February 14, 2018, Geocon West,
Inc. (Geocon) herein submits the results of our updated geotechnical investigation for the for planning
and design of the Lantern Crest multi-family development planned for approximately 13-acres located
immediately southeast of the intersection of Ynez Road and Date Street in Temecula, California.
The accompanying report presents our findings, conclusions and recommendations pertaining to the
geotechnical aspects of the proposed development. Based on the results of this study, we opine the site
is considered suitable for the proposed development provided the recommendations of this report are
followed.
Should you have questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON WEST, INC.
Luke Weidman
Staff Geologist, GIT 891
Shawn Foy Weedon
GE 2714
LW:PDT:LAB:SFW:hd
(Email) Addressee
Geocon Project No. T2903-22-01 - i - March 27, 2020
TABLE OF CONTENTS
1. PURPOSE AND SCOPE ...................................................................................................................... 1
2. SITE AND PROJECT DESCRIPTION ................................................................................................ 2
3. GEOLOGIC SETTING ......................................................................................................................... 3
4. GEOLOGIC MATERIALS .................................................................................................................. 3
4.1 Previously Placed Fill (Qpf) ....................................................................................................... 3
4.2 Quaternary Alluvium (Qal) ......................................................................................................... 3
5. GEOLOGIC STRUCTURE .................................................................................................................. 4
6. GROUNDWATER ............................................................................................................................... 4
7. GEOLOGIC HAZARDS ...................................................................................................................... 4
7.1 Surface Fault Rupture ................................................................................................................. 4
7.2 Seismicity ................................................................................................................................... 6
7.3 Ground Rupture .......................................................................................................................... 6
7.4 Liquefaction and Seismic Settlement ......................................................................................... 6
7.5 Expansive Soil ............................................................................................................................ 7
7.6 Hydrocompression ...................................................................................................................... 7
7.7 Landslides ................................................................................................................................... 7
7.8 Rock Fall Hazards....................................................................................................................... 7
7.9 Slope Stability ............................................................................................................................. 7
7.10 Tsunamis and Seiches ................................................................................................................. 8
7.11 Regional Subsidence ................................................................................................................... 8
8. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 9
8.1 General ........................................................................................................................................ 9
8.2 Soil Characteristics ................................................................................................................... 10
8.3 Grading ..................................................................................................................................... 11
8.4 Earthwork Grading Factors ....................................................................................................... 13
8.5 Utility Trench Backfill .............................................................................................................. 14
8.6 Seismic Design Criteria ............................................................................................................ 14
8.7 Foundation and Concrete Slabs-On-Grade ............................................................................... 16
8.8 Exterior Concrete Flatwork ...................................................................................................... 18
8.9 Conventional Retaining Walls .................................................................................................. 20
8.10 Lateral Design ........................................................................................................................... 23
8.11 Preliminary Pavement Recommendations ................................................................................ 24
8.12 Temporary Excavations ............................................................................................................ 26
8.13 Site Drainage and Moisture Protection ..................................................................................... 27
8.14 Plan Review .............................................................................................................................. 27
LIMITATIONS AND UNIFORMITY OF CONDITIONS
LIST OF REFERENCES
TABLE OF CONTENTS (Continued)
Geocon Project No. T2903-22-01 - ii - March 27, 2020
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geologic Map
APPENDIX A
EXPLORATORY EXCAVATIONS
APPENDIX B
LABORATORY TESTING
APPENDIX C
LABORATORY TEST RESULTS AND BORING LOGS, LEIGHTON, 2018
APPENDIX D
RECOMMENDED GRADING SPECIFICATIONS
Geocon Project No. T2903-22-01 - 1 - March 27, 2020
UPDATE GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of Geocon’s update geotechnical investigation for the proposed
multi-family development to be located on approximately 13-acres located southeast of the intersection of
Ynez Road and Date Street in Temecula, California (see Vicinity Map, Figure 1).
The purpose of this investigation is to evaluate subsurface soil and geologic conditions at the site and,
based on the conditions encountered, provide recommendations pertaining to the geotechnical aspects of
developing the property.
The scope of the investigation included reviewing available geotechnical reports near the site,
performing subsurface exploration, laboratory testing, engineering analyses, and preparing this report.
A summary of the information reviewed for this study is presented in the List of References.
The field exploration included excavating 10 geotechnical test pits (TP-1 through TP-10) utilizing a
rubber-tire backhoe equipped with a 24-inch bucket. We performed nuclear density tests at -1, -3, and
-5 feet below existing grades to measure in-situ compaction and moisture content per ASTM D 6938.
Appendix A presents a discussion of the field investigation and logs of the excavations.
The approximate locations of the exploratory test pits are presented on the Geologic Map, Figure 2.
We performed laboratory tests on soil samples obtained from the exploratory excavations to
evaluate pertinent physical and chemical properties for engineering analysis. The results of the
laboratory testing are presented in Appendix B. We also performed percolation testing onsite on
February 24, 2020 and reported under a separate cover. Appendix C presents the boring logs and
laboratory test data from the previous investigation performed by Leighton & Associates.
We used the Conceptual Grading Plan prepared by Polaris Development Consultants; Inc. for the
background of our Geologic Map, Figure 2. Elevations were obtained from Google Earth. Geocon does
not practice in the field of land surveying and is not responsible for the accuracy of such topographic
information.
The recommendations presented herein are based on analysis of the data obtained during the investigation
and Geocon’s experience with similar soil and geologic conditions.
Geocon Project No. T2903-22-01 - 2 - March 27, 2020
2. SITE AND PROJECT DESCRIPTION
The proposed multi-family project is a development that is located southeast of the intersection of
Ynez Road and Date Street, east of Interstate 15, in the City of Temecula, California. The site is
generally flat with elevations ranging from approximately 1,089 feet above mean sea level (MSL) to
1,097 feet above MSL at longitude 33.5337 and latitude -117.1641.
A portion of the property was sheet-graded with geotechnical observation and testing provided by
Leighton & Associates, Inc. (Leighton, 2008). Leighton also performed a geotechnical update report
for the project in 2016 where in they described the previous grading operations . The property is
currently vacant and covered in sparse vegetation consisting of annual weeds and grasses as shown in
the Existing Site Plan.
Existing Site Plan
Based on the existing and surrounding grades, we expect proposed grades will be one to six feet lower
than existing grades and minimal grading will be necessary, exclusive of remedial earthwork.
Due to the preliminary nature of the design currently, wall and column loads were not available.
We expect column loads for the proposed structures will be up to 100 kips, and wall loads will be up to
5 kips per linear foot. Once the design phase and foundation loading configuration proceeds to a more
finalized plan, the recommendations within this report should be reviewed and revised, if necessary.
If project details differ significantly from those described herein, we should be contacted for review
and possible revision to this report.
Geocon Project No. T2903-22-01 - 3 - March 27, 2020
3. GEOLOGIC SETTING
The project site is in the Temecula Valley within the Peninsular Ranges Geomorphic Province.
The Peninsular Ranges are bounded on the north by the Transverse Ranges (San Gabriel and
San Bernardino Mountains) and on the east by the San Andreas Fault.
More specifically, the site lies just southwest of the boundary of two structural blocks, the Santa Ana
Mountains block, and the Perris Block. These two structural blocks are separated by the Elsinore fault
zone. The Temecula Valley is a topographic depression that is bounded on the east by the Wildomar
branch of the Elsinore fault zone and on the west by the Willard branch of the Elsinore faul t zone.
Locally, the site is underlain by young (Holocene and late Pleistocene) alluvial deposits and siltstone
and sandstone of the Pauba Formation.
4. GEOLOGIC MATERIALS
Site geologic materials encountered consist of previously placed fill overlying the Pauba Formation to
the maximum depths of our explorations of 17 feet. The lateral extent of the materials encountered is
shown on the Geologic Map, Figure 2. The descriptions of the soil and geologic conditions are shown
on the test pits logs presented in Appendix A and the boring logs presented in Appendix C.
4.1 Previously Placed Fill (Qpf)
Previously placed fill exists across the site. The fill materials are thicker in the western portion of the
property and are relatively thin (2 feet or less) in the central and eastern portion of the property. Based
on a previous geotechnical investigation (Leighton, 2016), we expect the previously placed fill varies
in depth from 1 foot to 34 feet on site. Fill was observed to be a foot thick within TP-1 through TP-3,
TP-6, and TP-8. Within TP-7 and TP-9, fill was observed to the maximum depths explored (5 feet).
The Leighton Boring LB-3 encountered fill with a thickness of about 25 feet. The fill on site consists of
light brown to brown, silty sand that is generally medium dense to dense and damp with trace amounts
of gravel, grass, and roots. In-place tests taken with a nuclear density gauge showed dry density of the
material to range from 110.9 to 117.7 pounds per cubic foot (pcf) and moisture content to range from
10 to 12.6 percent.
4.2 Quaternary Alluvium (Qal)
We observed Quaternary Alluvium within TP-4 to the maximum depths explored (5 feet).
The Leighton Borings LB-1 and LB-2 indicate the alluvium extends to 25 feet deep. The alluvium
consists of medium dense, moist, dark brown, silty sand. Trace amounts of grass and roots were found
within the top foot. In place tests taken with a nuclear density gauge showed dry density of the material
to range from 102.9 to 108.4 pcf and moisture content to range from 9.8 to 11.3 percent.
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4.4 Pauba Formation (Qp)
The Pauba Formation was observed at or near the surface on most of the property. The engineering
properties of the Pauba Formation are similar to older alluvium in the general area. As encountered, the
Pauba Formation excavates as a medium dense to dense, light brown to dark brown, silty sand with
varying amounts of coarse sand. Within TP-6, the Pauba Formation excavated as a damp, reddish
brown, cohesionless, poorly-graded, coarse sand. In place tests taken with a nuclear density gauge
showed dry density of the material to range from 95.5 to 122.1 pcf and moisture content to range from
4.3 to 15.2 percent.
5. GEOLOGIC STRUCTURE
The Temecula Valley formed as a result of extensional faulting during the Miocene Epoch (between
5 and 24 million years before present). Subsequent faulting then changed from predominately
extension to predominately strike-slip (Harden 1998). Regionally, the Pauba Formation dips less than
10 degrees northeast and strikes to the northwest.
6. GROUNDWATER
We did not encounter groundwater during our subsurface exploration. It is not uncommon for shallow
seepage conditions to develop where none previously existed when sites are irrigated or infiltration is
implemented. Seepage is dependent on seasonal precipitation, irrigation, land use, among other factors,
and varies as a result. Proper surface drainage will be important to future performance of the project.
Riverside County Well #07S03W26J001S, located 0.65 miles away, shows current groundwater level to
be approximately 285 feet below the existing ground surface.
7. GEOLOGIC HAZARDS
7.1 Surface Fault Rupture
The numerous faults in southern California include active, potentially active, and inactive faults.
The criteria for these major groups are based on criteria developed by the California Geological
Survey (CGS) for the Alquist -Priolo Earthquake Fault Zone Program (Bryant and Hart, 1997).
By definition, an active fault is one that has had surface displacement within Holocene time (about
the last 11,700 years). A potentially active fault has demonstrated surface displacement during
Quaternary time (approximately the last 1.6 million years), but has had no known Holocene
movement. Faults that have not moved in the last 1.6 million years are considered inactive.
The site is not within a currently established State of California Alquist -Priolo Earthquake Fault
Zone (CGS, 2018) or a Riverside County Fault Hazard Zone for surface fault rupture hazards
(Riverside County RCIT, 2017). Active or potentially active faults with the potential for surface fault
rupture are not known to pass directly beneath the site (Jennings and Bryant, 2010). Therefore, the
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potential for surface rupture due to faulting occurring at the site during the design life of the
proposed development is considered low. However, the site is in the seismically active southern
California region, and could be subjected to moderate to strong grou nd shaking in the event of an
earthquake on one of the many active southern California faults.
The closest active fault to the site is the Wildomar fault located approximately 2 miles southeast of the
site. Faults within a 50-mile radius of the site are listed in Table 7.1.
TABLE 7.1
ACTIVE FAULTS WITHIN 50 MILES OF THE SITE
Fault Name Maximum Magnitude
(Mw)
Approximate Distance
from Site (mi) Direction from Site
Wildomar 6.8 2 SE
Glen Ivy North 6.8 15 NW
Casa Loma 6.9 19 NE
Clark 7.2 27 E
Elsinore (Glen Ivy) 6.8 28 NW
Elsinore (Julian) 7.1 33 SE
Coyote Creek 6.8 33 E-SE
San Gorgonio Pass 7.0 35 NE
Chino 6.7 41 NW
Earthquake Valley 6.5 42 SE
Coyote Mountain 6.8 43 E-SE
San Jacinto 6.7 44 N
Whittier 6.8 45 NW
Pinto Mountain 7.2 46 NE
Rose Canyon 7.2 48 S
North Branch 7.1 48 W-NW
Cucamonga 6.8 49 SE
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7.2 Seismicity
As with all southern California, the site has experienced historic earthquakes from various regional
faults. The seismicity of the region surrounding the site was formulated based on research of an
electronic database of earthquake data. Historic earthquakes in southern California of magnitude
6.0 and greater, their magnitude, distance, and direction from the site are listed in Table 7.2.
TABLE 7.2
HISTORIC EARTHQUAKE EVENTS WITH RESPECT TO THE SITE
Earthquake Date of
Earthquake Magnitude
Distance to
Epicenter
(Miles)
Direction
to
Epicenter (Oldest to Youngest)
Near Redlands July 23, 1923 6.3 33 NNW
Long Beach March 10, 1933 6.4 47 W
Tehachapi July 21, 1952 7.5 146 NW
San Fernando February 9, 1971 6.6 93 NW
Whittier Narrows October 1, 1987 5.9 64 WNW
Sierra Madre June 28, 1991 5.8 69 NW
Landers June 28, 1992 7.3 62 NE
Big Bear June 28, 1992 6.4 50 NNE
Northridge January 17, 1994 6.7 92 WNW
Hector Mine October 16, 1999 7.1 90 NE
Ridgecrest China Lake Fault July 5, 2019 7.1 156 NNW
7.3 Ground Rupture
Ground surface rupture occurs when movement along a fault is sufficient to cause a gap or rupture
where the upper edge of the fault zone intersects the earth surface. The potential for ground rupture is
considered to be very low due to the absence of active or potentially active faults at the subject site.
7.4 Liquefaction and Seismic Settlement
Liquefaction is a phenomenon in which loose, saturated, relatively cohesionless soil deposits lose shear
strength during strong ground motions. Primary factors controlling liquefaction include intensity and
duration of ground motion, gradation characteristics of the subsurface soils, in-situ stress conditions,
and the depth to groundwater. Seismically induced settlement may occur whether the potential for
liquefaction exists or not.
The current standard of practice as outlined in the Recommended Procedures for Implementation of
DMG Special Publication 117, Guidelines for Analyzing and Mitigating Liquefaction in California
(SCEC, 1999) requires a liquefaction analysis to a depth of 50 feet below the lowest portion of the
proposed structure. Liquefaction typically occurs in areas where the soils below the water table are
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composed of poorly consolidated, fine- to medium-grained, primarily sandy soil. In addition to the
requisite soil conditions, the ground acceleration and duration of the earthquake must also be of a
sufficient level to induce liquefaction.
According to the Riverside County Information Technology public web data (RCIT, 2018), the site is
not located within an area mapped as having a potential for liquefaction.
Based on our evaluations, total seismic dry settlement on the order of 1 inch and differential seismic
settlement on the order of ½ inch along 40 feet are anticipated to occur during seismic event.
7.5 Expansive Soil
The geologic units near the ground surface at the site generally consist of sand, silt, and clay.
Laboratory testing on samples collected by others (Leighton, 2016) indicated the site soils generally
possess a low to “very low” to “medium” expansion potential (expansion index of 90 or less).
7.6 Hydrocompression
Hydrocompression is the tendency of unsaturated soil structure to collapse upon wetting resulting in
the overall settlement of the affected soil and overlying foundations or improvements supported
thereon. Potentially compressible soils underlying the site are typically r emoved and recompacted
during remedial site grading. However, if compressible soil is left in -place, a potential for settlement
due to hydrocompression of the soil exists.
Due to the previous grading (Leighton 2008), we consider the potential for hydrocompression on this
site to be very low.
7.7 Landslides
The property is flat lying with no hills on or near the site. There are no known landslides near the site,
nor is the site in the path of any known or potential landslides. Therefore, landslides are not a design
consideration for the project.
7.8 Rock Fall Hazards
There are no hills ascending from the site, therefore, rock fall hazards are not a design consideration for
this project.
7.9 Slope Stability
No appreciable slopes are anticipated to be constructed within this site, therefore, slope failure is not a
design consideration.
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7.10 Tsunamis and Seiches
A tsunami is a series of long period waves generated in the ocean by a sudden displacement of large
volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or offshore
slope failures. The site is located 24 miles from a coastal area at an elevation of approximately 1094
feet above MSL. Therefore, tsunamis are not considered a significant hazard at the site.
A seiche is a run-up of water within a lake or embayment triggered by fault- or landslide-induced
ground displacement. The site not located adjacent to a body of water, therefore, seiches are not a
design consideration for the site.
7.11 Regional Subsidence
According to the Riverside County Information Technology public web data (RCIT, 2018), the site is
not located within an area mapped as having a potential for subsidence. Therefore, we consider
potential for subsidence on this site to be very low.
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8. CONCLUSIONS AND RECOMMENDATIONS
8.1 General
8.1.1 We opine soil or geologic conditions were not encountered during the investigation that
would preclude the proposed development of the project provided the recommendations
presented herein are followed and implemented during construction.
8.1.2 Potential geologic hazards at the site include seismic shaking and expansive soil of near
surface soils.
8.1.3 Upper portion previously placed fill, alluvium, and Pauba Formation are not considered
suitable for the support of additional compacted fill or settlement -sensitive improvements.
Remedial grading of the surficial soil will be required as discussed herein. The site soils are
suitable for re-use as engineered fill provided the recommendations of this report are followed.
8.1.4 The laboratory tests done by others (Leighton, 2016) indicate that the site soils should be
considered to have a “very low” to “medium” expansion potential. Highly expansive soils
will potentially be encountered at the site and they should be exported from the site or
selectively graded and placed in the deeper fill areas to allow for the placement of less
expansive material at the finish pad grade.
8.1.5 Groundwater was not encountered during our subsurface exploration. Riverside County
groundwater Well #07S03W26J001S located 0.65 miles to the southeast shows current
groundwater level to be at least 285 feet below the existing ground surface.
8.1.6 The moisture content of the site soils varies significantly across the site. Significant moisture
conditioning of the soils, including drying of the soils, should be expected before they can be
used as compacted fill.
8.1.7 Sand with little or no cohesion is present at the site and may be subject to caving in
un-shored excavations. Temporary excavations should be performed with care.
8.1.8 Buildings and the associated ancillary structures may be supported on a shallow conventional
foundations system following remedial grading. Overexcavation and recompaction of the site
soils must be observed and approved by a representative of Geocon.
8.1.9 Proper drainage should be maintained in order to preserve the engineering properties of the
compacted fill in planned improvement areas. Recommendations for site drainage are
provided herein.
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8.1.10 Once design or civil grading plans are made available, the recommendations within this
preliminary report should be reviewed and revised, as necessary. Additionally, as the project
design progresses toward a final design, changes in the design, location, or elevation of any
proposed improvements should be reviewed by this office. Geocon should be contacted to
evaluate the necessity for review and possible revision of this report.
8.2 Soil Characteristics
8.2.1 The in-situ soils at the site should generally be excavatable with moderate effort using
conventional earth moving equipment in proper functioning order.
8.2.2 The soil encountered in the field investigation is considered to be “non-expansive” and
“expansive” (expansion index [EI] of 20 or less and greater than 20, respectively) as defined
by 2019 California Building Code (CBC) Section 1803.5.3. Table 7.1 presents soil
classifications based on the expansion index. We expect a majority of the soil encountered
possess a “very low” to “medium” expansion potential (EI of 90 or less).
TABLE 8.2.2
SOIL CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) Expansion Classification 2019 CBC Expansion Classification
0 – 20 Very Low Non-Expansive
21 – 50 Low
Expansive 51 – 90 Medium
91 – 130 High
Greater Than 130 Very High
8.2.3 Laboratory testing, performed by others (Leighton, 2016), on a representative sample of site
material to measure the percentage of water-soluble sulfate content. Results from these tests
indicate that the site materials tested possess a water-soluble sulfate content of 0.003 percent
(33 parts per million [ppm]), that corresponds to an exposure class of “S0” to concrete
structures as defined by 2019 CBC Section 1904.3 and ACI 318. Table 8.2.3 presents a
summary of concrete requirements set forth by 2019 CBC Section 1904.3 and ACI 318.
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TABLE 8.2.3
REQUIREMENTS FOR CONCRETE EXPOSED TO
SULFATE-CONTAINING SOLUTIONS
Exposure
Class
Water-Soluble Sulfate
(SO4) Percent
by Weight
Cement Type
(ASTM C 150)
Maximum Water
to Cement Ratio
by Weight1
Minimum
Compressive
Strength (psi)
S0 SO4<0.10 No Type
Restriction n/a 2,500
S1 0.10<SO4<0.20 II 0.50 4,000
S2 0.20<SO4<2.00 V 0.45 4,500
S3 SO4>2.00 V+Pozzolan or
Slag 0.45 4,500
1 Maximum water to cement ratio limits do not apply to lightweight concrete
8.2.4 The presence of water-soluble sulfates is not a visually discernible characteristic; therefore,
other soil samples from the sites could yield different concentrations. Additionally, over time
landscaping activities along the access roads or from nearby developments (i.e., addition of
fertilizers and other soil nutrients) may affect the concentration.
8.2.5 Laboratory testing indicates the site soils have a minimum electrical resistivity of
3,220 ohm-cm, possess 21 parts per million (ppm) chloride, 33 ppm sulfate, and have a pH
of 7.52. As shown in Table 8.2.5, the site is not classified as “corrosive”; however, moderate
corrosively potential of soil is anticipated.
TABLE 8.2.5
CALTRANS CORROSION GUIDELINES
Corrosion
Exposure
Resistivity
(ohm-cm) Chloride (ppm) Sulfate (ppm) pH
Corrosive <1,100 500 or greater 1,500 or greater 5.5 or less
8.2.6 Geocon does not practice in the field of corrosion engineering. Therefo re, further evaluation
by a corrosion engineer may be performed if improvements that could be susceptible to
corrosion are planned.
8.3 Grading
8.3.1 Grading should be performed in accordance with the Recommended Grading Specifications
contained in Appendix D and the Grading Ordinances of the City of Temecula.
8.3.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the City inspector, owner or developer, grading contractor, civil engineer, and geotechnical
engineer in attendance. Special soil handling and/or the grading plans can be discussed at
that time.
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8.3.3 Site preparation should begin with the removal of deleterious material, debris, buried trash,
and vegetation. The depth of removal should be such that material exposed in cut areas or
soil to be used as fill is relatively free of organic matter. Material generated during stripping
and/or site demolition should be exported from the site. Rock over 6 inches in diameter
should be screened and removed, and not used in the engineered fill.
8.3.4 The upper portion of previously placed fill, alluvium, and Pauba Formation within a 1:1
(horizontal to vertical) projection of the limits of grading should be removed to expose
competent fill (with a dry density of at least 90 percent of the laboratory maximum dry
density); alluvium, or Pauba Formation with a relative compaction of at least 85 percent,
based on ASTM D1557, or is at least 3 feet and extend 2 feet below the bottom of the
footings, whichever is greater. Based on our findings, we expect that surficial soils will
require remedial excavation and proper compaction. Areas of loose, dry, or compressible
soils may require deeper excavation and processing prior to fill placement. The engineering
geologist should evaluate the actual depth of removal during grading operations.
8.3.5 Removals in pavement and walkway areas should extend at least 2 feet below subgrade.
Where overexcavation and compaction is to be conducted, the excavations should be
extended laterally a minimum distance of 5 feet beyond the building footprint or for a
distance equal to the depth of removal, whichever is greater. Patios and building
appurtenances should be considered a part of the building footprint when determining the
limits of lateral excavation. The bottom of the excavations should be scarified to a depth of
at least 1 foot, moisture conditioned to 0 to 2 percent above optimum moisture content, and
properly compacted.
8.3.6 Based on the depth of the previously placed fill, deeper removals may be needed. Removals
should be extended to H/3 (where H is the maximum depth of fill within building footprint)
and within a 1:1 projection of the building. H/3 recommendations include the previously
placed fill/alluvium and previously placed fill/Pauba Formation contacts.
8.3.7 Recommendations for alternative grading techniques such as slot cutting or shoring, or
deepened footings adjacent existing roads and structures can be provided as needed.
8.3.8 The fill placed within 4 feet of proposed foundations should possess a “very low” to “low”
expansion potential (EI of 50 or less).
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8.3.9 If perched groundwater or saturated materials are encountered during remedial grading,
extensive drying and mixing with dryer soil may be required, if the saturated material is to be
utilized as fill material in achieving finished grades. The excavated materials should then be
moisture conditioned to 0 to 2 percent above optimum moisture content, prior to placement
as compacted fill.
8.3.10 The site should be brought to finish grade elevations with fill compacted in layers. Layers of
fill should be no thicker than will allow for adequate bonding and compaction.
Fill, including backfill and scarified ground surfaces, should be compacted to a dry density
of at least 90 percent of the laboratory maximum dry density, at 0 to 2 percent above
optimum moisture content as determined by ASTM D 1557. Fill materials placed below
optimum moisture content may require additional moisture conditioning prior to placing
additional fill. Earthwork should be observed, and compacted fill tested by representatives of
Geocon.
8.3.11 If needed, import fill should consist of granular materials with a “very low” to “medium”
expansion potential (EI of 90 or less), non-corrosive, generally free of deleterious material,
and contain rock no larger than 6 inches. Geocon should be notified of the import soil source
and should be afforded the opportunity to perform laboratory testing of the import soil prior
to its arrival at the site to evaluate its suitability as fill material.
8.4 Earthwork Grading Factors
8.4.1 Estimates of shrinkage factors are based on empirical judgments comparing the material in
its existing or natural state as encountered in the exploratory excavations to a compacted
state. Variations in natural soil density and in compacted fill density render shrinkage value
estimates as rough approximations. As an example, the contractor can compact the fill to a
dry density of 90 percent or higher of the laboratory maximum dry density. Thus, the
contractor has an approximately 10 percent range of control over the fill volume. Based on
the densities measured in the test pits and our experience with similar site soils, the
shrinkage of previously placed fill, alluvium, and Pauba Formation is expected to be on the
order of 0 to 7 percent, when site soils are compacted to at least 90 percent of the laboratory
maximum dry density. This estimate is for preliminary quantity estimates only. Due to the
variations in the actual shrinkage/bulking factors, a balance area should be provided to
accommodate variations.
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8.5 Utility Trench Backfill
8.5.1 Utility trenches should be properly backfilled in accordance with the requirements of the
City of Temecula and the latest edition of the Standard Specifications for Public Works
Construction (Greenbook). The pipes should be bedded with well-graded crushed rock or
clean sands (Sand Equivalent greater than 30) to a depth of at least one foot over the pipe.
The bedding material must be inspected and approved in writing by a qualified representative
of Geocon. The use of well-graded crushed rock is only acceptable if used in conjunction
with filter fabric to prevent the gravel from having direct contact with soil. The remainder of
the trench backfill may be derived from onsite soil or approved import soil. Backfill of utility
trenches should not contain rocks greater than 3 inches in diameter. The use of 2-sack slurry
and controlled low strength material (CLSM) are also acceptable as backfill. However,
consideration should be given to the possibility of differential settlem ent where the slurry
ends and earthen backfill begins. These transitions should be minimized and additional
stabilization should be considered at these transitions.
8.5.2 Trench excavation bottoms must be observed and approved in writing by th e Geotechnical
Engineer, prior to placing bedding materials, fill, gravel, or concrete.
8.5.3 Utility trench backfill should be placed in layers no thicker than will allow for adequate
bonding and compaction. Utility backfill should be compacted to a dry density of at least
90 percent of the laboratory maximum dry density and moisture conditioned to 0 to 2 percent
above optimum moisture content as determined by ASTM D 1557. Backfill at the finish
subgrade elevation of new pavements should be compacted to at least 95 percent of the
maximum dry density. Backfill materials placed below the recommended moisture content
may require additional moisture conditioning prior to placing additional fill.
8.6 Seismic Design Criteria
8.6.1 Table 8.6.1 summarizes summarizes site-specific design criteria obtained from the 2019
California Building Code (CBC; Based on the 2018 International Building Code [IBC] and
ASCE 7-16), Chapter 16 Structural Design, Section 1613 Earthquake Loads. We used the
computer program U.S. Seismic Design Maps, provided by the Structural Engineers
Association (SEA) to calculate the seismic design parameters. The short spectral response
uses a period of 0.2 second. We evaluated the Site Class based on the discu ssion in Section
1613.2.2 of the 2019 CBC and Table 20.3-1 of ASCE 7-16. The values presented herein are
for the risk-targeted maximum considered earthquake (MCER). Sites designated as Site Class
D, E and F may require additional analyses if requested by the project structural engineer and
client.
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TABLE 8.6.1
2019 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2019 CBC Reference
Site Class D Section 1613.2.2
MCER Ground Motion Spectral Response
Acceleration – Class B (short), SS 1.577g Figure 1613.2.1(1)
MCER Ground Motion Spectral Response
Acceleration – Class B (1 sec), S1 0.589g Figure 1613.2.1(2)
Site Coefficient, FA 1.000 Table 1613.2.3(1)
Site Coefficient, FV 1.711* Table 1613.2.3(2)
Site Class Modified MCER Spectral Response
Acceleration (short), SMS 1.577g Section 1613.2.3 (Eqn 16-36)
Site Class Modified MCER Spectral Response
Acceleration – (1 sec), SM1 1.08g* Section 1613.2.3 (Eqn 16-37)
5% Damped Design
Spectral Response Acceleration (short), SDS 1.051g Section 1613.2.4 (Eqn 16-38)
5% Damped Design
Spectral Response Acceleration (1 sec), SD1 0.72g* Section 1613.2.4 (Eqn 16-39)
*Note: Using the code-based values presented in this table, in lieu of a performing a ground motion hazard analysis, requires
the exceptions outlined in ASCE 7-16 Section 11.4.8 be followed by the project structural engineer. Per Section 11.4.8 of
ASCE/SEI 7-16, a ground motion hazard analysis should be performed for projects for Site Class “E” sites with Ss greater
than or equal to 1.0g and for Site Class “D” and “E” sites with S1 greater than 0.2g. Section 11.4.8 also provides exceptions
which indicates that the ground motion hazard analysis may be waived provided the exceptions are followed.
8.6.2 Table 8.6.2 presents the mapped maximum considered geometric mean (MCEG) seismic
design parameters for projects located in Seismic Design Categories of D through F in
accordance with ASCE 7-16.
TABLE 8.6.2
ASCE 7-16 PEAK GROUND ACCELERATION
Parameter Value ASCE 7-16 Reference
Mapped MCEG Peak Ground Acceleration, PGA 0.702g Figure 22-7
Site Coefficient, FPGA 1.100 Table 11.8-1
Site Class Modified MCEG Peak Ground
Acceleration, PGAM 0.772g Section 11.8.3 (Eqn 11.8-1)
8.6.3 The Maximum Considered Earthquake Ground Motion (MCE) is the level of ground motion
that has a 2 percent chance of exceedance in 50 years, with a statistical return period of
2,475 years. According to the 2019 California Building Code and ASCE 7-16, the MCE is
to be utilized for the evaluation of liquefaction, lateral spreading, seismic settlements, and it
is our understanding that the intent of the building code is to maintain “Life Safety” during
a MCE event.
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8.6.4 Deaggregation of the MCE peak ground acceleration was performed using the USGS online
BETA Unified Hazard Tool, 2014 (updated) Conterminous U.S. Dynamic edition.
The result of the deaggregation analysis indicates that the predominant earthquake
contributing to the MCE peak ground acceleration is characterized as a 7.71 magnitude
event occurring at a hypocentral distance of 1.74 kilometers from the site.
8.6.5 Conformance to the criteria in the herein for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or grou nd failure will not occur if
a large earthquake occurs. The primary goal of seismic design is to protect life, not to avoid
all damage, since such design may be economically prohibitive.
8.7 Foundation and Concrete Slabs-On-Grade
8.7.1 The foundation recommendations presented herein are for the proposed buildings subsequent
to the recommended grading. We understand that future buildings will be supported on
conventional shallow foundations with a concrete slab-on-grade deriving support in newly
placed engineered fill.
8.7.2 Foundations for the structures may consist of either continuous strip footings and/or isolated
spread footings. Conventionally reinforced continuous footings should be at least 18 inches
wide and extend at least 24 inches below lowest adjacent pad grade. Isolated spread footings
should have a minimum width of 24 inches and should extend at least 24 inches below
lowest adjacent pad grade. The foundations should be embedded in accordance with the
recommendations herein and the Wall/Column Footing Dimension Detail.
Wall/Column Footing Dimension Detail
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8.7.3 From a geotechnical engineering standpoint, concrete slabs-on-grade for the structure should
be at least 4 inches thick and be reinforced with at least No. 3 steel reinforcing bars placed
24 inches on center in both directions. The concrete slab-on-grade recommendations are
based on soil support characteristics only. The project structural engineer should evaluate the
structural requirements of the concrete slab for supporting equipment and storage loads.
A thicker concrete slab may be required for heavier loading conditions. To reduce the effects
of differential settlement on the foundation system, thickened slabs and/or an increase in
steel reinforcement can provide a benefit to reduce concrete cracking
8.7.4 Following remedial grading, foundations for the buildings may be designed for an
allowable soil bearing pressure of 2,500 psf (dead plus live load). The allowable bearing
pressure may be increased by one -third for transient loads due to wind or seismic forces.
8.7.5 Based on a footing of 6.5 feet, the maximum expected static settlement for the planned
structures, supported on conventional foundation systems with the allowable bearing
pressures, and deriving support in engineered fill is estimated to be 1 inch and to occur
below the heaviest loaded structural element. Settlement of the foundation system.
Differential settlement is not expected to exceed ½ inch over a horizontal distance of 40 feet.
8.7.6 Once the design and foundation loading configuration proceeds to a more finalized plan, the
estimated settlements within this report should be reviewed and revised, if necessary.
8.7.7 Steel reinforcement for continuous footings should consist of at least four No. 4 steel
reinforcing bars placed horizontally in the footings, two near the top and two near the
bottom. Steel reinforcement for the spread footings should be designed by the project
structural engineer.
8.7.8 Foundation excavation bottoms must be observed and approved in writing by a qualified
representative of Geocon, prior to placement of reinforcing steel or concrete.
8.7.9 Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture-
sensitive materials should be underlain by a vapor retarder. The vapor retarder design should
be consistent with the guidelines presented in the American Concrete Institute’s (ACI) Guide
for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-06).
The vapor retarder used should be specified by the project architect or developer based
on the type of floor covering that will be installed and if the struct ure will possess a
humidity-controlled environment.
8.7.10 The bedding sand thickness should be evaluated by the project foundation engineer,
architect, and/or developer. However, we should be contacted to provide recommendations if
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the bedding sand is thicker than 4 inches. Placement of 3 inches and 4 inches of sand is
common practice in southern California for 5-inch and 4-inch thick slabs, respectively.
The foundation engineer should provide appropriate concrete mix design criteria and curing
measures that may be utilized to assure proper curing of the slab to reduce the potential for
rapid moisture loss and subsequent cracking and/or slab curl. We suggest that the foundation
design engineer present the concrete mix design and proper curing methods on the
foundation plans. It is critical that the foundation contractor understands and follows the
recommendations presented on the foundation plans.
8.7.11 Special subgrade presaturation is not deemed necessary prior to placing concr ete; however,
the exposed foundation and slab subgrade soil should be moisturized to maintain a moist
condition of at least 2 percent above optimum moisture content.
8.7.12 The recommendations of this report are intended to reduce the potential for cracking of slabs
due to expansive soil (if present), differential settlement of existing soil or soil with varying
thicknesses. However, even with the incorporation of the recommendations presented herein,
foundations, walls, and slabs-on-grade placed on such conditions may still exhibit some
cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage
cracks is independent of the supporting soil characteristics. Their occurrence may be reduced
and/or controlled by limiting the slump of the concrete, proper concrete placement and
curing, and by the placement of crack control joints at periodic intervals, in p articular where
re-entrant slab corners occur.
8.7.13 Geocon should be consulted to provide additional design parameters as required by the
structural engineer.
8.7.14 Foundation excavation bottoms must be observed and approved in writing by the
Geotechnical Engineer, prior to placing fill, steel, gravel or concrete.
8.8 Exterior Concrete Flatwork
8.8.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the recommendations presented in Table 8.8.1. The recommended steel
reinforcement would help reduce the potential for cracking.
TABLE 8.8.1
MINIMUM CONCRETE FLATWORK RECOMMENDATIONS
Expansion
Index, EI Minimum Steel Reinforcement* Options Minimum
Thickness
EI < 90 6x6-W2.9/W2.9 (6x6-6/6) welded wire mesh 4 Inches No. 3 Bars 18 inches on center, Both Directions
*In excess of 8 feet square.
Geocon Project No. T2903-22-01 - 19 - March 27, 2020
8.8.2 The subgrade soil should be properly moisturized and compacted prior to the placement of
steel and concrete. The subgrade soil should be compacted to a dry density of at least
90 percent of the laboratory maximum dry density near to slightly above optimum moisture
content in accordance with ASTM D 1557.
8.8.3 Even with the incorporation of the recommendations of this report, the exterior concrete
flatwork has a potential to experience some uplift due to expansive soil beneath grade.
The steel reinforcement should overlap continuously in flatwork to reduce the potential for
vertical offsets within flatwork. Additionally, flatwork should be structurally connected to
the curbs, where possible, to reduce the potential for offsets between the curbs and the
flatwork.
8.8.4 Concrete flatwork should be provided with crack control joints to reduce and/or control
shrinkage cracking. Crack control spacing should be determined by the project structural
engineer based upon the slab thickness and intended usage. Criteria of the American
Concrete Institute (ACI) should be taken into consideration when establishing crack control
spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compact ed
in accordance with criteria presented in the grading section prior to concrete placement.
Subgrade soil should be properly compacted and the moisture content of subgrade soil
should be verified prior to placing concrete. Base materials will not be requi red below
concrete improvements.
8.8.5 Where exterior flatwork abuts the structure at entrant or exit points, the exterior slab should
be dowelled into the structure’s foundation stemwall. This recommendation is intended to
reduce the potential for differential elevations that could result from differential settlement or
minor heave of the flatwork. Dowelling details should be designed by the project structural
engineer.
8.8.6 The recommendations presented herein are intended to reduce the potential for cracking of
exterior slabs as a result of differential movement. However, even with the incorporation of
the recommendations presented herein, slabs-on-grade will still crack. The occurrence of
concrete shrinkage cracks is independent of the soil supporting characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, the use
of crack control joints and proper concrete placement and curing. Crack control joints should
be spaced at intervals no greater than 12 feet. Literature provided by the Portland Concrete
Association (PCA) and American Concrete Institute (ACI) present recommendations for
proper concrete mix, construction, and curing practices, and should be incorporated into
project construction.
Geocon Project No. T2903-22-01 - 20 - March 27, 2020
8.9 Conventional Retaining Walls
8.9.1 Retaining walls should be designed using the values presented in Table 8.9.1. Soil with an
expansion index (EI) of greater than 90 should not be used as backfill material behind
retaining walls.
TABLE 8.9.1
RETAINING WALL DESIGN RECOMMENDATIONS
Parameter Value
Active Soil Pressure, A (Fluid Density, Level Backfill) 40 pcf
Active Soil Pressure, A (Fluid Density, 2:1 Sloping Backfill) 55 pcf
Seismic Pressure, S 15H psf
At-Rest/Restrained Walls Additional Uniform Pressure (0 to 8 Feet High) 7H psf
At-Rest/Restrained Walls Additional Uniform Pressure (8+ Feet Hig h) 13H psf
Expected Expansion Index for the Subject Property EI<50 / 90
H equals the height of the retaining portion of the wall
8.9.2 The project retaining walls should be designed as shown in the Retaining Wall Loading
Diagram.
Retaining Wall Loading Diagram
Geocon Project No. T2903-22-01 - 21 - March 27, 2020
8.9.3 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals the
height of the retaining portion of the wall) at the top of the wall. Where walls are restrained
from movement at the top (at-rest condition), an additional uniform pressure should be
applied to the wall. For retaining walls subject to vehicular loads within a horizontal distance
equal to two-thirds the wall height, a surcharge equivalent to 2 feet of fill soil should be
added.
8.9.4 The structural engineer should determine the Seismic Design Category for the project in
accordance with Section 1613.3.5 of the 2019 CBC or Section 11.6 of ASCE 7-10.
For structures assigned to Seismic Design Category of D, E, or F, retaining walls that
support more than 6 feet of backfill should be designed with seismic lateral pressure in
accordance with Section 1803.5.12 of the 2019 CBC. The seismic load is dependent on the
retained height where H is the height of the wall, in feet, and the calculated loads result in
pounds per square foot (psf) exerted at the base of the wall and zero at the top of the wall.
8.9.5 Retaining walls should be designed to ensure stability against overturning sliding, and
excessive foundation pressure. Where a keyway is extended below the wall base with the
intent to engage passive pressure and enhance sliding stability, it is not necessary to consider
active pressure on the keyway.
8.9.6 Drainage openings through the base of the wall (weep holes) should not be used where the
seepage could be a nuisance or otherwise adversely affect the property adja cent to the base
of the wall. The recommendations herein assume a properly compacted granular (EI of 90 or
less) free-draining backfill material with no hydrostatic forces or imposed surcharge load.
The retaining wall should be properly drained as shown in the Typical Retaining Wall
Drainage Detail. If conditions different than those described are expected, or if specific
drainage details are desired, Geocon Incorporated should be contacted for additional
recommendations.
Typical Retaining Wall Drainage Detail
Geocon Project No. T2903-22-01 - 22 - March 27, 2020
8.9.7 The retaining walls may be designed using either the active and restrained (at-rest) loading
condition or the active and seismic loading condition as suggested by the structural engineer.
Typically, it appears the design of the restrained condition for retaining wall loading may be
adequate for the seismic design of the retaining walls. However, the active earth pr essure
combined with the seismic design load should be reviewed and also considered in the design
of the retaining walls.
8.9.8 In general, wall foundations should be designed in accordance with Table 8.9.8.
The proximity of the foundation to the top of a slope steeper than 3:1 could impact the
allowable soil bearing pressure. Therefore, retaining wall foundati ons should be deepened
such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of
the slope.
TABLE 8.9.8
SUMMARY OF RETAINING WALL FOUNDATION RECOMMENDATIONS
Parameter Value
Minimum Retaining Wall Foundation Width 12 inches
Minimum Retaining Wall Foundation Depth 12 Inches
Minimum Steel Reinforcement Per Structural Engineer
Allowable Bearing Capacity 2,000 psf
Estimated Total Settlement 1 Inch
Estimated Differential Settlement ½ Inch in 40 Feet
8.9.9 The recommendations presented herein are generally applicable to the design of rigid
concrete or masonry retaining walls. In the event that other types of walls (such as
mechanically stabilized earth [MSE] walls, soil nail walls, or soldier pile walls) are planned,
Geocon Incorporated should be consulted for additional recommendations.
8.9.10 Unrestrained walls will move laterally when backfilled and loading is applied. The amount
of lateral deflection is dependent on the wall height, the type of soil used for backfill, and
loads acting on the wall. The retaining walls and improvements above the retaining walls
should be designed to incorporate an appropriate amount of lateral deflection as determined
by the structural engineer.
Geocon Project No. T2903-22-01 - 23 - March 27, 2020
8.9.11 Soil contemplated for use as retaining wall backfill, including import materials, should be
identified in the field prior to backfill. At that time, Geocon Incorporated should obtain
samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures may
be necessary if the backfill soil does not meet the required expansion index or shear strength.
City or regional standard wall designs, if used, are based on a specific active lateral earth
pressure and/or soil friction angle. In this regard, on-site soil to be used as backfill may or
may not meet the values for standard wall designs. Geocon Incorporated should be consulted
to assess the suitability of the on-site soil for use as wall backfill if standard wall designs will
be used.
8.10 Lateral Design
8.10.1 Table 8.10.1 should be used to help design the proposed structures and improvements to
resist lateral loads for the design of footings or shear keys. The allowable passive pressure
assumes a horizontal surface extending at least 5 feet, or three times the surface generating
the passive pressure, whichever is greater. The upper 12 inches of material in areas not
protected by floor slabs or pavement should not be included in design for passive resistance.
TABLE 8.10.1
SUMMARY OF LATERAL LOAD DESIGN RECOMMENDATIONS
Parameter Value
Passive Pressure Fluid Density 250 pcf
Coefficient of Friction (Concrete and Soil) 0.3
Coefficient of Friction (Along Vapor Barrier) 0.2 to 0.25*
*Per manufacturer’s recommendations.
8.10.2 The passive and frictional resistant loads can be combined for design purposes.
The lateral passive pressures may be increased by one-third when considering
transient loads due to wind or seismic forces.
Geocon Project No. T2903-22-01 - 24 - March 27, 2020
8.11 Preliminary Pavement Recommendations
8.11.1 We calculated the flexible pavement sections in general conformance with the Caltrans
Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) Based on the
soil classifications, we used an assumed R-value of 30 for the preliminary pavement design
recommendations. Preliminary flexible pavement sections are presented in Table 8.12.1 and
are based on a range of Traffic Indices specified in Standard 115 of the City Temecula
Department of Public Works, Improvement Standard Drawings for Public Works
Construction. The civil engineer should evaluate the final traffic indices for pavements.
The final pavement design should be based on R-value testing of soils at subgrade.
Streets should be designed in accordance with the City of Temecula Department of Public
Works, Improvement Standard Drawings for Public Works Construction, when final Traffic
Indices (TI’s) and R-value test results of subgrade soil are completed.
TABLE 8.11.1
PRELIMINARY FLEXIBLE PAVEMENT SECTIONS
Road Classification/Use
Assumed
Subgrade
R-Value
Asphalt
Concrete
(Inches)
Aggregate Base
Materials
(Inches)
Residential Cul-de-sac / Parking
(TI = 5.0) 30 3 6
Minor Collector
(TI = 5.5) 30 3½ 7
Major Collector
(TI = 7.5) 30 4½ 11
Minor Arterial
(TI = 8.0) 30 5 11
Primary Arterial
(TI = 8.5) 30 5½ 12
Major Arterial
(TI = 9.0) 30 6 12
8.11.2 The upper 12 inches of the subgrade soil should be compacted to a dry density of at least
95 percent of the laboratory maximum dry density, at 0 to 2 percent optimum moisture
content, and be in accordance with the City of Temecula Department of Public Works,
Improvement Standard Drawings for Public Works Construction.
8.11.3 The aggregate base materials and asphalt concrete materials should conform to
Section 200-2.2 and Section 203-6, respectively, of the Greenbook. Base materials should be
compacted to a dry density of at least 95 percent of the laboratory maximum dry density near
to slightly above optimum moisture content. Asphalt concrete should be compacted to a
density of 95 percent of the laboratory Hveem density in accordance with ASTM D 2726.
Geocon Project No. T2903-22-01 - 25 - March 27, 2020
8.11.4 A rigid Portland cement concrete (PCC) pavement section should be placed in driveway
aprons and cross gutters. We calculated the rigid pavement section in general conformance
with the procedure recommended by the American Concrete Institute report ACI 330R-08
Guide for Design and Construction of Concrete Parking Lots using the parameters presented
in Table 8.11.4.
TABLE 8.11.4
RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value
Modulus of subgrade reaction, k 100 pci
Modulus of rupture for concrete, MR 500 psi
Traffic Category, TC A and C
Average daily truck traffic, ADTT 10 and 100
8.11.5 Based on the criteria presented herein, the PCC pavement sections should have a minimum
thickness as presented in Table 8.11.5.
TABLE 8.11.5
RIGID PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Access Lanes (TC=A) 6.5
Entrance / Driveway Aprons (TC=C) 7.0
8.11.6 The PCC pavement should be placed over subgrade soil that is compacted to a dry density of
at least 95 percent of the laboratory maximum dry density, at 0 to 2 percent above optimum
moisture content. This pavement section is based on a minimum concrete compressive
strength of approximately 3,000 psi (pounds per square inch). Base material will not be
required beneath concrete improvements.
8.11.7 A thickened edge or integral curb should be constructed on the outside of concrete slabs
subjected to wheel loads. The thickened edge should be 1.2 times the slab thickness or a
minimum thickness of 2 inches, whichever results in a thicker edge, and taper back to the
recommended slab thickness 4 feet behind the face of the slab (e.g., a 9-inch-thick slab
would have an 11-inch-thick edge). Reinforcing steel will not be necessary within the
concrete for geotechnical purposes with the possible exception of dowels at construction
joints as discussed herein.
Geocon Project No. T2903-22-01 - 26 - March 27, 2020
8.11.8 In order to control the location and spread of concrete shrinkage cracks, crack-control joints
(weakened plane joints) should be included in the design of the concrete pavement slab in
accordance with the referenced ACI report.
8.11.9 Performance of the pavements is highly dependent on providing positive surface drainage
away from the edge of the pavement. Ponding of water on or adjacent to the pavement
surfaces will likely result in pavement distress and subgrade failure. Drainage from
landscaped areas should be directed to controlled drainage structures. Landscape areas
adjacent to the edge of asphalt pavements are not recommended due to the potential for
surface or irrigation water to infiltrate the underlying permeable aggregate base and cause
distress. Where such a condition cannot be avoided, consideration should be given to
incorporating measures that will significantly reduce the potential for subsurface water
migration into the aggregate base. If planter islands are planned, the perimeter curb should
extend at least 6 inches below the level of the base materials.
8.12 Temporary Excavations
8.12.1 The recommendations included herein are provided for stable excavations. It is the
responsibility of the contractor and their competent person to ensure all excavations,
temporary slopes and trenches are properly constructed and maintained in accordance with
applicable OSHA guidelines in order to maintain safety and the stability of the excavations
and adjacent improvements. These excavations should not be allowed to become saturated or
to dry out. Surcharge loads should not be permitted to a distance equal to the height of the
excavation from the top of the excavation. The top of the excavation should be a minimum
of 15 feet from the edge of existing improvements. Excavations steeper than those
recommended or closer than 15 feet from an existing surface improvement should be shored
in accordance with applicable OSHA codes and regulations.
8.12.2 The stability of the excavations is dependent on the design and construction of the shoring
system and site conditions. Therefore, Geocon Incorporated cannot be responsible for site
safety and the stability of the proposed excavations.
Geocon Project No. T2903-22-01 - 27 - March 27, 2020
8.13 Site Drainage and Moisture Protection
8.13.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2019 CBC 1804.4 or other applicable
standards. In addition, surface drainage should be directed away from the top of slopes into
swales or other controlled drainage devices. Roof and pavement drainage should be directed
into conduits that carry runoff away from the proposed structure.
8.13.2 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water is allowed to infiltrate the soil for prolonged periods of time.
8.13.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement’s subgrade and base course.
We recommend that area drains to collect excess irrigation water and transmit it to drainage
structures or impervious above-grade planter boxes be used. In addition, where landscaping
is planned adjacent to the pavement, we recommend construction of a cutoff wall along the
edge of the pavement that extends at least 6 inches below the bottom of the base material.
8.13.4 If not properly constructed, there is a potential for distress to improvements and properties
located hydrologically down gradient or adjacent to infiltration areas. Factors such as the
amount of water to be detained, its residence time, and soil permeability have an important
effect on seepage transmission and the potential adverse impacts that may occur if the storm
water management features are not properly designed and constructed. We have not
performed a hydrogeology study at the site. Down-gradient and adjacent structures may be
subjected to seeps, movement of foundations and slabs, or other impacts as a result of wat er
infiltration.
8.14 Plan Review
8.14.1 Geocon should be provided the opportunity to review the grading and foundation plans for
the project prior to final submittal, to verify that the plans have been prepared in substantial
conformance with the recommendations of this report. Additional analyses may be required
after review of the project plans.
Geocon Project No. T2903-22-01 March 27, 2020
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The recommendations of this report pertain only to the site investigated and are based upon the
assumption that the soil conditions do not deviate from those disclosed in the investigation.
If any variations or undesirable conditions are encountered during construction, or if the
proposed construction will differ from that anticipated herein, Geocon should be notified so
that supplemental recommendations can be given. The evaluation or identification of the
potential presence of hazardous materials was not part of the scope of services provided by
Geocon.
2. This report is issued with the understanding that it is the responsibility of the owner, or of their
representative, to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors carry out
such recommendations in the field.
3. The findings of this report are valid as of the date of this report. However, changes in t he
conditions of a property can occur with the passage of time, whether they are due to natural
processes or the works of man on this or adjacent properties. In addition, changes in applicable
or appropriate standards may occur, whether they result from legislation or the broadening of
knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by
changes outside our control. Therefore, this report is subject to review and should not be relied
upon after a period of three years.
4. The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations prese nted for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
Geocon Project No. T2903-22-01 Mach 26, 2020
LIST OF REFERENCES
1. Abrahamson, N., and Silva, W., 2008, Summary of the Abrahamson & Silva NGA
Ground-Motion Relations, Earthquake Spectra, Volume 24, No. 1, pages 67–97;
Earthquake Engineering Research Institute.
2. American Concrete Institute, 2014, Building Code Requirements for Structural Concrete and
Commentary on Building Code Requirements for Structural Concrete, prepared by the American
Concrete Institute Committee 318, dated September.
3. American Concrete Institute, 2011, Building Code Requirements for Structural Concrete, Report
by ACI Committee 318.
4. American Concrete Institute, 2008, Guide for Design and Construction of Concrete Parking
Lots, Report by ACI Committee 330.
5. ASCE 7-16, 2011, Minimum Design Loads for Buildings and Other Structures,
Second Printing, April 6.
6. Boore, D. M. and G. M Atkinson, 2008, Ground-Motion Prediction for the Average Horizontal
Component of PGA, PGV, and 5%-Damped PSA at Spectral Periods Between 0.01 and 10.0 S,
Earthquake Spectra, Volume 24, Issue 1, pages 99-138, dated February.
7. California Building Standards Commission, 2019, California Building Code (CBC),
California Code of Regulations Title 24, Part 2.
8. California Department of Conservation, 1996, Division of Mines and Geology, Probabilistic
Seismic Hazard Assessment for the State of California, Open File Report 96-08.
9. California Department of Transportation (Caltrans), 2018, Division of Engineering Services,
Materials Engineering and Testing Services, Corrosion Branch, Corrosion Guidelines,
Version 3.0, dated March.
10. Caltrans, 2015, Standard Specifications.
11. California Geological Survey (CGS), 2003, Earthquake Shaking Potential for California,
from USGS/CGS Seismic Hazards Model, CSSC No. 03-02.
12. California Geological Survey (CGS), 2003, Probabilistic Seismic Hazards Mapping-Ground
Motion Page, CGS Website: www.conserv.ca.gov/cgs/rghm/pshamap.
13. California Geological Survey (CGS), 2018, Earthquake Zones of Required Investigation
Murrieta Quadrangle, CGS Website:
https://gmw.conservation.ca.gov/SHP/EZRIM/Maps/MURRIETA_EZRIM.pdf.
14. California Geological Survey, Seismic Shaking Hazards in California, 2003, Based on the
USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 10% probability of being
exceeded in 50 years; (revised April).
http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html
15. California Geological Survey, 2008, Special Publication 117A, Guidelines for Evaluating and
Mitigating Seismic Hazards in California, Revised and Re-adopted September 11.
LIST OF REFERENCES (Continued)
Geocon Project No. T2903-22-01 March 27, 2020
16. Campbell, K. W. and Y. Bozorgnia, 2008, NGA Ground Motion Model for the Geometric Mean
Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra
for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication in the NGA
Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, dated February.
17. Chiou, Brian S. J. and Robert R. Youngs, 2008, A NGA Model for the Average Horizontal
Component of Peak Ground Motion and Response Spectra, preprint for article to be published in
NGA Special Edition for Earthquake Spectra, dated Spring.
18. Riverside County, 2019, Well Record Log for Well #07S03W26J001S.
19. FEMA, 2017, Online Flood Hazard Maps, http://www.esri.com/hazards/index.html.
20. Harden, D.R., California Geology, Prentice-Hall, Inc., 479 pp., dated 1998.
21. Hart, E.W., and Bryant, W. A., 1997, Fault- Rupture Hazards Zones in California: Alquist-Priolo
Earthquake Fault Zoning Act with Index to Fault Zone Maps, CGS Special Publication 42,
revised 2018.
22. Jennings, Charles W. and Bryant, William A., 2010, Fault Activity Map of California, California
Division of Mines and Geology Map No. 6.
23. Kennedy, M.P., Morton, D.M., Alvarez, R.M., and Morton, Greg, 2003, Preliminary Geologic
Map of the Murrieta 7.5' Quadrangle, Riverside County, California: U.S. Geological Survey,
Open-File Report OF-2003-189, scale 1:24,000
24. Leighton and Associates, 2008, Update As-graded Report, Lots 39 through 52, Tract 29639-2,
Service Commercial, Harveston, City of Temecula, California, Project No. 110231 -073, dated
June 23, 2008.
25. Leighton and Associates, 2016, Geotechnical Exploration Report West Living - Harveston
Temecula, California, Project No. 11362.003, dated November 9, 2016.
26. Legg, M. R., J. C. Borrero, and C. E. Synolakis,2002, Evaluation of Tsunami Risk to Southern
California Coastal Cities, NEHRP Professional Fellowship Report, dated January.
27. OSHPD, 2018, Seismic Design Maps, https://seismicmaps.org, accessed April 21, 2018.
28. Polaris Development Consultants, Inc., Conceptual Grading Plan Lantern Crest Temecula, dated
November 3 2019.
29. Public Works Standards, Inc., 2015, Standard Specifications for Public Works Construction
“Greenbook,” Published by BNi Building News.
30. Riverside County Land Information System, 2019
https://gis.countyofriverside.us/Html7Viewer/?viewer=MMC_Public
31. Southern California Earthquake Data Center, 2013, 3D Velocity Model for Southern California
Version 4, Caltech Dataset. doi:10.7909/C3WD3xH1.
32. US Geological Survey, 2017, Seismic Design Maps Web Application,
http://earthquake.usgs.gov/designmaps/us/application.php, accessed April 21.
SOURCE: Google Earth, 2020
VICINITY MAP
LANTERN CREST TEMECULA
DATE STREET AND YNEZ ROAD
TEMECULA, CALIFORNIA
MARCH 2020 PROJECT NO. T2903-22-01 FIG. 1LCW
SCALE: 1” = 1000’
0’ 1000’ 2000’
PROJECT LOCATION
N
PROJECT NO. T2903-22-01 FIG. 2
LANTERN CREST TEMECULA
DATE STREET AND YNEZ ROAD
TEMECULA, CALIFORNIA
GEOLOGIC MAP
LCW
Source: Polaris Development Consultants, Inc., Conceptual Grading Plan
Lantern Crest Temecula, dated November 3 2019
GEOCON LEGEND
Locations are approximate
MARCH 2020
……. PERCOLATION
TEST LOCATION
(GEOCON, 2020)
P-4
P-2
…….TEST PIT
LOCATION
TP-10
TP-1
TP-2
TP-3
……. PROJECT
EXTENTS
Qp ……. PAUBA FORMATION
Qpf ……. PREVIOUSLY PLACED
FILL
……. GEOLOGIC CONTACT
Qpf
Qpf
Qp
TP-6
TP-5
TP-4
TP-9
P-3P-4
Qal
Qp
QpTP-10
LB-8
……. BORING LOCATION
(LEIGHTON 2016)
LB-5
LB-6
LB-2
LB-3
LB-1
LB-7
LB-8
P-1
Qal
Qp
P-1
LB-4
TP-7
TP-8
……. QUATERNARY ALLUVIUM
*Surficial soils less than 2 feet
APPENDIX A
Geocon Project No. T2903-22-01 - A-1- March 27, 2020
APPENDIX A
EXPLORATORY EXCAVATIONS
Geocon performed the field investigation on February 24, 2020, which included the excavation of nine
test pits (TP-1 through TP-9) to depths of approximately 5 feet, to observe the subsurface geological
conditions at the site and collect bulk samples for laboratory testing.
We took nuclear density tests on in-situ material to measure dry density and moisture content at -1, -3,
and -5 feet below existing grades.
Bulk samples were collected and transported to our laboratory for testing. Results of laboratory testing
is presented in Appendix B.
The soil conditions encountered in the borings were visually examined, classified and logged in general
accordance with the Unified Soil Classification System (USCS). Logs of the test pits are presented on
Figures A-1 through A-9 in Appendix A. The logs depict the soil and geologic conditions encountered
and the depth at which samples were obtained. The approximate locations of the test pits are depicted
on the Geologic Map, Figure 2.
98.6
101.4
98.1
SM
SM 12.3
11.7
12.4
PREVIOUSLY PLACED FILL (Qpf)
Silty SAND, loose, damp, light brown; fine to coarse sand; trace gravel;
organics
PAUBA FORMATION (Qp)
Silty SAND, dense, moist, light brown; fine to medium sand
- Relatuve compaction 83%
- Thin sand lens; relative compaction 85%
- Relative compaction 83%
Total Depth = 5'
Groundwater not encountered
Backfilled with cuttings 02/24/2020
CO
N
T
E
N
T
(
%
)
... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
Figure A-1,
Log of Test Pit TP-1, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
T2903-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
1090
BACKHOE BUCKET 24"
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
02/24/2020
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
TEST PIT TP-1
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2903-22-01
102.6
102.3
98.1
SM
SM 13.2
7.0
4.3
PREVIOUSLY PLACED FILL (Qpf)
Silty SAND, medium dense, damp, light brown; fine to medium sand;
trace gravel; organics
PAUBA FORMATION (Qp)
Silty SAND, dense, moist, light brown; fine to medium sand
-Relative compaction 86%
- Becomes pale brown; relative compaction 86%
-Relative compaction 83%
- Becomes a poorly graded sand; loose; dry
Total Depth = 5'
Groundwater not encountered
Backfilled with cuttings 02/24/2020
CO
N
T
E
N
T
(
%
)
... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
Figure A-2,
Log of Test Pit TP-2, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
T2903-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
1091
BACKHOE BUCKET 24"
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
02/24/2020
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
TEST PIT TP-2
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2903-22-01
TP3@1-5'122.1
109.6
106.1
SM
SM 10.3
9.0
9.4
PREVIOUSLY PLACED FILL (Qpf)
Silty SAND, loose, damp, dark brown; fine to coarse sand; organics
PAUBA FORMATION (Qp)
Silty SAND, dense, moist, brown; fine to coarse sand; relative
compaction 91%
- Relative compaction 81%
- Relative compaction 79%
Total Depth = 5'
Groundwater not encountered
Backfilled with cuttings 02/24/2020
CO
N
T
E
N
T
(
%
)
... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
Figure A-3,
Log of Test Pit TP-3, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
T2903-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
1090
BACKHOE BUCKET 24"
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
02/24/2020
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
TEST PIT TP-3
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2903-22-01